WorldWideScience

Sample records for lepidochelys olivacea electronic

  1. Light and scanning electron microscopic studies on the esophageal spines in the Pacific ridley turtle, Lepidochelys olivacea.

    Science.gov (United States)

    Yoshie, S; Honma, Y

    1976-02-01

    The peculairly specialized esophagus of the Pacific ridley turtle, Lepidochelys olivacea, was described by light and scanning electron microscopic studies. The esophagus is lined by a stratified squamous epithelium with remarkable keratinization, and its major part forms a number of large spines which have been called "pharyngeal teeth." The epithelium consists of three strate: stratum germinativum, stratum spinosum and stratum corneum. The surface of the spine is covered by a scaly keratin of possibly sloughing cells, and the cornified layer on the spine is very thick (more than 100 mu), reaching 3 to 7 times the depth of the corresponding layer in other parts. This peculiar structure in the marine turtle without toothed jaws prabably is used for breaking food into small pieces.

  2. huevo de tortuga lora (lepidochelys olivacea

    Directory of Open Access Journals (Sweden)

    M\\u00F3nica Pereira-Zamora

    2007-01-01

    Full Text Available Penetración de Vibrio mimicus a través de la cáscara del huevo de tortuga lora (Lepidochelys olivacea. El objetivo de esta investigación consistió en determinar la capacidad de penetración del Vibrio mimicus a través de la cáscara del huevo. La investigación se realizó en el Centro Nacional de Ciencia y Tecnología de Alimentos en el año 2000. Se inoculó la superfi cie de la cáscara con la bacteria y se procedió a incubar las muestras por 72 horas a 25ºC. Después de este período se observaron las muestras bajo el microscopio electrónico. Los resultados obtenidos demuestran que el Vibrio mimicus se reproduce en la superfi cie externa de la cáscara del huevo de tortuga lora, y no es capaz de penetrarla después de las 72 horas de incubación a 25ºC. Por lo tanto, cualquier tratamiento que se aplique con el fi n de reducir la contaminación con el vibrio y mejorar la inocuidad de los huevos, debe aplicarse en su exterior.

  3. Schistosomus Reflexus Syndrome in Olive Ridley Sea Turtles ( Lepidochelys olivacea).

    Science.gov (United States)

    Bárcenas-Ibarra, A; Rojas-Lleonart, I; Lozano-Guzmán, R I; García-Gasca, A

    2017-01-01

    The olive ridley sea turtle ( Lepidochelys olivacea), considered the most abundant sea turtle species, is listed as vulnerable on the International Union for Conservation of Nature Red List. The most important nesting areas are located in the Eastern Pacific, and congenital malformations have been previously reported in this species. The present study was conducted in a single population at El Verde beach, one of the most important nesting beaches for the species in the northwestern Mexican Pacific. The study was based on embryos that had been incubated in a controlled environment. Schistosomus reflexus syndrome (SRS) was observed in 124 of 20 257 olive ridley embryos (0.6%), comprising 124 of 400 (31%) cases of congenital malformations over a 7-month period. Affected embryos had malformations of the carapace, bridge, or plastron, resulting in exposure of the abdominal or thoracic viscera, as well as spinal malformation and abnormal positioning of limbs adjacent to the head with subsequent ankylosis. SRS phenotypes (although lethal) varied from mild to severe, although most cases were severe. SRS was mostly associated with congenital malformations in the neck (short neck, 80%), tail (anury, 38%), and flippers (different types of dysmelias, 53%). In most cases of severe SRS, ankyloses were present. Documenting these findings could be important to identify the cause of the developmental defects, and identification of the cause of the defects may be of significance to the population and to our efforts to manage this and other populations at risk.

  4. First report of an olive ridley (Lepidochelys olivacea inside the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    O. REVUELTA

    2015-04-01

    Full Text Available We report the first confirmed occurrence of a Lepidochelys olivacea in the Mediterranean Sea based on the study of an individual stranded on a beach, located in the town of Oropesa del Mar (40º05ʹ32ʺN, 0º08ʹ02ʺE, Castellón province, East Spain, in May 2014. Morphological and genetic analyses were used to confirm the identification of the species. The individual had a sequence that matched the 470 bp Lepidochelys olivacea haplotype F (Genbank accession number: AF051773, found in several Atlantic populations. This becomes one of the northernmost known occurrences of olive ridleys in the world and is the first reports of this species in the Mediterranean Sea.

  5. Overlapping genetic codes for overlapping frameshifted genes in Testudines, and Lepidochelys olivacea as special case.

    Science.gov (United States)

    Seligmann, Hervé

    2012-12-01

    Mitochondrial genes code for additional proteins after +2 frameshifts by reassigning stops to code for amino acids, which defines overlapping genetic codes for overlapping genes. Turtles recode stops UAR → Trp and AGR → Lys (AGR → Gly in the marine Olive Ridley turtle, Lepidochelys olivacea). In Lepidochelys the +2 frameshifted mitochondrial Cytb gene lacks stops, open reading frames from other genes code for unknown proteins, and for regular mitochondrial proteins after frameshifts according to the overlapping genetic code. Lepidochelys' inversion between proteins coded by regular and overlapping genetic codes substantiates the existence of overlap coding. ND4 differs among Lepidochelys mitochondrial genomes: it is regular in DQ486893; in NC_011516, the open reading frame codes for another protein, the regular ND4 protein is coded by the frameshifted sequence reassigning stops as in other turtles. These systematic patterns are incompatible with Genbank/sequencing errors and DNA decay. Random mixing of synonymous codons, conserving main frame coding properties, shows optimization of natural sequences for overlap coding; Ka/Ks analyses show high positive (directional) selection on overlapping genes. Tests based on circular genetic codes confirm programmed frameshifts in ND3 and ND4l genes, and predicted frameshift sites for overlap coding in Lepidochelys. Chelonian mitochondria adapt for overlapping gene expression: cloverleaf formation by antisense tRNAs with predicted anticodons matching stops coevolves with overlap coding; antisense tRNAs with predicted expanded anticodons (frameshift suppressor tRNAs) associate with frameshift-coding in ND3 and ND4l, a potential regulation of frameshifted overlap coding. Anaeroby perhaps switched between regular and overlap coding genes in Lepidochelys. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Spirorchiid Infection in Olive Ridley Turtle, Lepidochelys olivacea (Eschscholtz, 1829) (Testudines: Cheloniidae), from Brazil.

    Science.gov (United States)

    Jerdy, H; Ribeiro, R B; Silva, M A; Medina, R M; Werneck, M R; Carvalho, E C Q

    2016-04-01

    The Olive Ridley turtle, Lepidochelys olivacea (Eschscholtz, 1829) (Testudines: Cheloniidae), is 1 of the 5 species of sea turtle found along the coast of Brazil. Little is known regarding infection by species of the family Spirorchiidae in the host, as only 1 report exists. This case report describes granulomas in different tissues associated to type 1 and 3 spirorchiid eggs in 5 L. olivacea from the Brazilian coast. The occurrence of the eggs was considered an incidental finding and may have contributed to the debility and death of the hosts. This is the second report of tissue lesions due to spirorchids eggs in this host and the first occurrence in Olive Ridley turtle from the Brazilian coast.

  7. Trace elements in blood of sea turtles Lepidochelys olivacea in the Gulf of California, Mexico.

    Science.gov (United States)

    Zavala-Norzagaray, A A; Ley-Quiñónez, C P; Espinosa-Carreón, T L; Canizalez-Román, A; Hart, C E; Aguirre, A A

    2014-11-01

    This study determined the concentrations of heavy metals in blood collected from Pacific Ridley sea turtles (Lepidochelys olivacea) inhabiting the coast of Guasave, Mexico, in the Gulf of California. The highest reported metal concentration in blood was Zn, followed by Se. Of nonessential toxic metals, As was reported in higher percentage compared to Cd. The concentrations of metals detected were present as follows: Zn > Se > Mn > As > Ni > Cd > Cu. Cd concentration in blood is higher in our population in comparison with other populations of L. olivacea, and even higher in other species of sea turtles. Our study reinforces the usefulness of blood for the monitoring of the levels of contaminating elements, and is easily accessible and nonlethal for sea turtles.

  8. Multiple paternity and female-biased mutation at a microsatellite locus in the olive ridley sea turtle (Lepidochelys olivacea)

    NARCIS (Netherlands)

    Hoekert, W.E.J.; Neufeglise, N.; Schouten, A.D.; Menken, S.B.J.

    2002-01-01

    Multiple paternity in the olive ridley sea turtle (Lepidochelys olivacea) population nesting in Suriname was demonstrated using two microsatellite loci, viz., Ei8 and Cm84. The large number of offspring sampled per clutch (70 on average, ranging from 15 to 103) and the number of alleles found at the

  9. Relocations of sea turtle nests of Lepidochelys olivacea, Dermochelys coriacea and Chelonia mydas in the Galibi Nature Reserve, Suriname

    NARCIS (Netherlands)

    Schouten, A.D.; Weijerman, M.; Tienen, van L.H.G.; Hoekert, W.E.J.

    1997-01-01

    SCHOUTEN, A.D., WEIJERMAN, M., VAN TIENEN, L.H.G. & W.E.J. HOEKERT, 1997. Relocations of Sea Turtle nests of Lepidochelys olivacea, Dermochelys coriace and Chelonia mydas in the Galibi Nature Reserve, Suriname. Studies Nat. Hist. Caribbean Region 73, Amsterdam, 1997: 63-69. Relocation of nests of

  10. Distribution and Feeding Behavior of Omorgus suberosus (Coleoptera: Trogidae) in Lepidochelys olivacea Turtle Nests.

    Science.gov (United States)

    Baena, Martha L; Escobar, Federico; Halffter, Gonzalo; García-Chávez, Juan H

    2015-01-01

    Omorgus suberosus (Fabricius, 1775) has been identified as a potential predator of the eggs of the turtle Lepidochelys olivacea (Eschscholtz, 1829) on one of the main turtle nesting beaches in the world, La Escobilla in Oaxaca, Mexico. This study presents an analysis of the spatio-temporal distribution of the beetle on this beach (in areas of high and low density of L. olivacea nests over two arrival seasons) and an evaluation, under laboratory conditions, of the probability of damage to the turtle eggs by this beetle. O. suberosus adults and larvae exhibited an aggregated pattern at both turtle nest densities; however, aggregation was greater in areas of low nest density, where we found the highest proportion of damaged eggs. Also, there were fluctuations in the temporal distribution of the adult beetles following the arrival of the turtles on the beach. Under laboratory conditions, the beetles quickly damaged both dead eggs and a mixture of live and dead eggs, but were found to consume live eggs more slowly. This suggests that O. suberosus may be recycling organic material; however, its consumption of live eggs may be sufficient in some cases to interrupt the incubation period of the turtle. We intend to apply these results when making decisions regarding the L. olivacea nests on La Escobilla Beach, one of the most important sites for the conservation of this species.

  11. Energetics during hatchling dispersal of the olive ridley turtle Lepidochelys olivacea using doubly labeled water.

    Science.gov (United States)

    Clusella Trullas, Susana; Spotila, James R; Paladino, Frank V

    2006-01-01

    Studies of metabolism are central to the understanding of the ecology, behavior, and evolution of reptiles. This study focuses on one phase of the sea turtle life cycle, hatchling dispersal, and gives insight into energetic constraints that dispersal imposes on hatchlings. Hatchling dispersal is an energetically expensive phase in the life cycle of the olive ridley turtle Lepidochelys olivacea. Field metabolic rates (FMRs), determined using the doubly labeled water (DLW) method, for L. olivacea hatchlings digging out of their nest chamber, crawling at the sand surface, and swimming were five, four, and seven times, respectively, the resting metabolic rate (RMR). The cost of swimming was 1.5 and 1.8 times the cost of the digging and crawling phases, respectively, and we estimated that if L. olivacea hatchlings swim at frenzy levels, they can rely on yolk reserves to supply energy for only 3-6 d once they reach the ocean. We compared our RMR and FMR values by establishing an interspecific RMR mass-scaling relationship for a wide range of species in the order Testudines and found a scaling exponent of 1.06. This study demonstrates the feasibility of using the DLW method to estimate energetic costs of free-living sea turtle hatchlings and emphasizes the need for metabolic studies in various life-history stages.

  12. Dimorphic DNA methylation during temperature-dependent sex determination in the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Venegas, Daniela; Marmolejo-Valencia, Alejandro; Valdes-Quezada, Christian; Govenzensky, Tzipe; Recillas-Targa, Félix; Merchant-Larios, Horacio

    2016-09-15

    Sex determination in vertebrates depends on the expression of a conserved network of genes. Sea turtles such as Lepidochelys olivacea have temperature-dependent sex determination. The present work analyses some of the epigenetic processes involved in this. We describe sexual dimorphism in global DNA methylation patterns between ovaries and testes of L. olivacea and show that the differences may arise from a combination of DNA methylation and demethylation events that occur during sex determination. Irrespective of incubation temperature, 5-hydroxymethylcytosine was abundant in the bipotential gonad; however, following sex determination, this modification was no longer found in pre-Sertoli cells in the testes. These changes correlate with the establishment of the sexually dimorphic DNA methylation patterns, down regulation of Sox9 gene expression in ovaries and irreversible gonadal commitment towards a male or female differentiation pathway. Thus, DNA methylation changes may be necessary for the stabilization of the gene expression networks that drive the differentiation of the bipotential gonad to form either an ovary or a testis in L. olivacea and probably among other species that manifest temperature-dependent sex determination. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Distribution and Feeding Behavior of Omorgus suberosus (Coleoptera: Trogidae in Lepidochelys olivacea Turtle Nests.

    Directory of Open Access Journals (Sweden)

    Martha L Baena

    Full Text Available Omorgus suberosus (Fabricius, 1775 has been identified as a potential predator of the eggs of the turtle Lepidochelys olivacea (Eschscholtz, 1829 on one of the main turtle nesting beaches in the world, La Escobilla in Oaxaca, Mexico. This study presents an analysis of the spatio-temporal distribution of the beetle on this beach (in areas of high and low density of L. olivacea nests over two arrival seasons and an evaluation, under laboratory conditions, of the probability of damage to the turtle eggs by this beetle. O. suberosus adults and larvae exhibited an aggregated pattern at both turtle nest densities; however, aggregation was greater in areas of low nest density, where we found the highest proportion of damaged eggs. Also, there were fluctuations in the temporal distribution of the adult beetles following the arrival of the turtles on the beach. Under laboratory conditions, the beetles quickly damaged both dead eggs and a mixture of live and dead eggs, but were found to consume live eggs more slowly. This suggests that O. suberosus may be recycling organic material; however, its consumption of live eggs may be sufficient in some cases to interrupt the incubation period of the turtle. We intend to apply these results when making decisions regarding the L. olivacea nests on La Escobilla Beach, one of the most important sites for the conservation of this species.

  14. Ultrastructure and characteristics of eggshells of the olive ridley turtle (Lepidochelys olivacea) from Gahirmatha, India.

    Science.gov (United States)

    Sahoo, G; Mohapatra, B K; Sahoo, R K; Mohanty-Hejmadi, P

    1996-01-01

    The structure of a chelonian eggshell is of prime importance for the developing embryo. It acts as a protective covering as well as mediator in the exchange of heat and water. The fresh eggshell of the olive ridley (Lepidochelys olivacea) turtle displays a variety of structural forms in their aragonite framework. Its netted substrate, loose texture and poorly organised crystallites favour the easy exchange of air and water during its development. The shell consists mostly of calcium in carbonate form and K, Mg, Fe, Ni, Pb, Zn, Co, Cr, Cu, Mn and Cd in traces. Ba and Sr in traces are also a feature of the thermal analysis graph. Phosphorous was not detected in the shell and its absence eliminates an earlier suggestion of it being a key factor in the development of aragonite crystals in the inorganic structure of marine turtle eggshells. Its combustion characteristics, which have not been previously reported, are recorded.

  15. [Cloacal and nasal bacterial flora of Lepidochelys olivacea (Testudines: Cheloniidae) from the North Pacific Coast of Costa Rica].

    Science.gov (United States)

    Santoro, Mario; Orrego, Carlos Mario; Hernández Gómez, Giovanna

    2006-03-01

    Cloacal and nasal bacterial flora of Lepidochelys olivacea (Testudines: Cheloniidae) from the North Pacific coast of Costa Rica. The aerobic cloacal and nasal bacterial flora of 45 apparently healthy female olive ridley sea turtles (Lepidochelys olivacea) was studied at Nancite nesting beach, in Santa Rosa National Park (Costa Rican North Pacific) during July and August 2002. Bacterial samples were obtained by inserting sterile swabs directly into the cloaca and the nasal cavities of the turtles. Ninety-nine aerobic bacterial isolates, including 10 Gram-negative and 5 Gram-positive bacteria, were recovered. The most common bacteria cultured were Aeromonas spp. (13/45) and Citrobacter freundi (6/45) from cloacal samples and Bacillus spp. (32/45), Staphylococcus aureus (6/45) and Corynebacterium spp. (5/45) from nasal ducts. The results of the present study showed that the aerobic bacterial flora of nesting female olive ridleys was composed of several potential human and animal microbe pathogens.

  16. Developmental cardiovascular physiology of the olive ridley sea turtle (Lepidochelys olivacea).

    Science.gov (United States)

    Crossley, Dane Alan; Crossley, Janna Lee; Smith, Camilla; Harfush, Martha; Sánchez-Sánchez, Hermilo; Garduño-Paz, Mónica Vanessa; Méndez-Sánchez, José Fernando

    2017-09-01

    Our understanding of reptilian cardiovascular development and regulation has increased substantially for two species the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina) during the past two decades. However, what we know about cardiovascular maturation in many other species remains poorly understood or unknown. Embryonic sea turtles have been studied to understand the maturation of metabolic function, but these studies have not addressed the cardiovascular system. Although prior studies have been pivotal in characterizing development, and factors that influence it, the development of cardiovascular function, which supplies metabolic function, is unknown in sea turtles. During our investigation we focused on quantifying how cardiovascular morphological and functional parameters change, to provide basic knowledge of development in the olive ridley sea turtle (Lepidochelys olivacea). Embryonic mass, as well as mass of the heart, lungs, liver, kidney, and brain increased during turtle embryo development. Although heart rate was constant during this developmental period, arterial pressure approximately doubled. Further, while embryonic olive ridley sea turtles lacked cholinergic tone on heart rate, there was a pronounced beta adrenergic tone on heart rate that decreased in strength at 90% of incubation. This beta adrenergic tone may be partially originating from the sympathetic nervous system at 90% of incubation, with the majority originating from circulating catecholamines. Data indicates that olive ridley sea turtles share traits of embryonic functional cardiovascular maturation with the American alligator (Alligator mississippiensis) but not the common snapping turtle (Chelydra serpentina). Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Levels of perfluorinated acids (PFCAs) in different tissues of Lepidochelys olivacea sea turtles from the Escobilla beach (Oaxaca, Mexico).

    Science.gov (United States)

    Pasanisi, Eugenia; Cortés-Gómez, Adriana A; Pérez-López, Marcos; Soler, Francisco; Hernández-Moreno, David; Guerranti, Cristiana; Martellini, Tania; Fuentes-Mascorro, Gisela; Romero, Diego; Cincinelli, Alessandra

    2016-12-01

    Lepidochelys olivacea is the most abundant and globally distributed sea turtle species in the world and thus, monitoring this species for persistent organic pollutants, such as perfluorinated chemicals, is fundamental for their protection. This study was the first to evaluate the occurrence of five PFCAs (PFOA, PFNA, PFDA, PFUnA, PFDoA) in liver and blood samples of Olive Ridley turtle population from the Escobilla beach (Oaxaca, Mexico). PFDA and PFUnA were the predominant PFCs in blood samples (detected in 93% and 84% of samples, respectively) and were also present in the highest concentrations. Liver samples showed higher PFCA concentrations than whole blood samples, with PFNA and PFDA the most abundant PFCs congeners in liver samples, detected in 65% and 47% of the samples, respectively. The measured levels of contaminants in the blood samples of Lepidochelys olivacea sea turtles were compared to the levels reported in the literature for other turtle species. While linear significant correlations between PFNA, PFDA and PFUnA concentrations in blood samples and curved carapace lengths were determined, no correlation was found for PFOA, supporting the hypothesis that sea turtles could have a higher ability to eliminate this perfluorinated chemical from their blood than other PFCAs. However, we do not know if the concentrations are species or sampling areas dependent. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Correlation among thermosensitive period, estradiol response, and gonad differentiation in the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Merchant-Larios, H; Ruiz-Ramirez, S; Moreno-Mendoza, N; Marmolejo-Valencia, A

    1997-09-01

    Reptile embryos with temperature sex determination have a thermosensitive period (TSP). The finding that exogenous estradiol (E2) overcomes the effect of male-promoting temperature led to the idea that temperature may regulate estrogen concentration in the gonad during TSP. Since interspecific variations in TSP and in the effect of exogenous E2 exist, we undertook a study in the olive ridley Lepidochelys olivacea. Four parameters were correlated: the TSP (time dimension), the thermosensitive stages (rate of development), gonad development (histological aspect), and the estradiol response. Two kinds of experiments were performed: (1) Eggs were shifted once, at different stages of development, from a male-promoting temperature to a female-temperature (or vice versa) for the remainder of development. (2) Eggs at male-promoting temperature were treated once with 6 or 12 microg of estradiol (E2) at various times of incubation. Sex ratio was established around hatching in each experimental series. We found that the temporal dimension of the TSP was around 7 days (Days 20-27 of incubation) at a male-promoting or a female-promoting temperature. The rate of development of the whole embryo and gonadal growth was faster at female-promoting temperature than at male-promoting temperature. Formation of the genital ridge began at stage 21-22 and histological differentiation of the gonads occurred around stage 26-27. Although these stages coincided with the TSP, at male-promoting temperature the thermosensitive stages occurred earlier (from stages 20-21 to stages 23-24) than at female-promoting temperature (from stages 23-24 to stages 26-27). Thus, at male promoting-temperature, sex was determined in embryos with incipient or undifferentiated gonads. In contrast, E2 treatment continued to feminize the gonads of embryos at a male-promoting temperature beyond the TSP up to stage 25-26, but the E2-induced ovaries were significantly smaller than temperature-induced ovaries. It is

  19. Flora bacteriana cloacal y nasal de Lepidochelys olivacea (Testudines: Cheloniidae en el pacífico norte de Costa Rica

    Directory of Open Access Journals (Sweden)

    Mario Santoro

    2006-03-01

    Full Text Available Con el objetivo de determinar la flora normal aerobia, cloacal y nasal de la tortuga lora (Lepidochelys olivacea , entre los meses de julio y agosto del 2002,se colectaron muestras bacteriológicas de 45 quelonios aparentemente sanos,durante el desove en Playa Nancite,Parque Nacional Santa Rosa, Costa Rica, a través del uso de hisopos estériles que se introdujeron en la cloaca y en uno de los conductos nasales. De las muestras recolectadas se obtuvieron e identificaron un total de 99 aislamientos, incluyendo 10 grupos de Gram-negativos y 5 de Gram-positivos. De cada tortuga se obtuvo un promedio de 0.7 bacterias de la cloaca y 1.4 de las cavidades nasales. Las bacterias más frecuente halladas fueron Aeromonas spp.(13/45 y Citrobacter freundi (6/45 en la cloaca, y Bacillus spp. (32/45,Staphylococcus aureus (6/45y Corynebacterium spp.(5/45en las cavidades nasales. En este investigación, la flora microbiana de las tortugas lora resultó constituida por microorganismos potencialmente patógenos para el ser humano y las tortugas.Cloacal and nasal bacterial flora of Lepidochelys olivacea (Testudines: Cheloniidae from the North Pacific coast of Costa Rica.The aerobic cloacal and nasal bacterial flora of 45 apparently healthy female olive ridley sea turtles (Lepidochelys olivacea was studied at Nancite nesting beach,in Santa Rosa National Park (Costa Rican North Pacificduring July and August 2002.Bacterial samples were obtained by inserting sterile swabs directly into the cloaca and the nasal cavities of the turtles.Ninety-nine aerobic bacterial isolates, including 10 Gram-negative and 5 Gram-positive bacteria, were recovered.The most common bacteria cultured were Aeromonas spp. (13/45 and Citrobacter freundi (6/45from cloacal samples and Bacillus spp.(32/45, Staphylococcus aureus (6/45and Corynebacterium spp.(5/45from nasal ducts.The results of the present study showed that the aerobic bacterial flora of nesting female olive ridleys was composed of

  20. Identifikasi Gen Aerolysin dan Sensitivitas Antibiotik Aeromonas Hydrophila Penyebab Kematian Tukik (Lepidochelys olivacea di Pulau Serangan, Bali

    Directory of Open Access Journals (Sweden)

    Rima Ratnanggana Prasetya

    2017-06-01

    Full Text Available The purpose of this study was to evaluate the pathogene of Aeromonas hydrophila genes (Aerolysin as the cause of Lepidochelys olivacea death and to perform the antibiotic sensitivity test for antibiotic that often used in order to provide the best antibiotic treatment in the field case. The method used was the identification test using primary cultures on Tryptic Soy Agar (TSA and Mac Conkey Agar (MCA medium, then followed by Gram staining, oxidase, catalase, and biochemical tests. Then, aerolysin genes detection was performed by using Polymerase Chain Reaction (PCR method, while oxytetracycline, chloramphenicol, streptomycin, and kanamycin were tested for their sensitivity. From five samples of dead Lepidochelys olivacea, bleeding on the liver and intestine were observed. The identification result of bacteria was found A. hydrophila, and identified the gene encoding aerolysin. The antibiotic sensitivity test showed a sensitive category of A. hydrophila with a sensitivity level were oxytetracycline, chloramphenicol, kanamycin, and streptomycin. The main cause of Lepidochelys olivacea death in Turtle Conservation and Education Centre, Serangan Island, Bali was A. hydrophila which contains aerolysin genes, in which oxytetracycline seems to be the most effective drug for the treatment. ABSTRAK Tujuan dari penelitian ini adalah membuktikan adanya gen patogen (Aerolysin pada Aeromonas hydrophila sebagai penyebab kematian tukik penyu abu-abu serta mengetahui kepekaan obat antibiotic yang sering digunakan sehingga dapat memberikan terapi yang tepat pada kasus di lapangan. Metode penelitian yang digunakan adalah uji identifikasi menggunakan kultur primer pada media Tryptic Soy Agar (TSA dan Mac Conkey Agar (MCA, dilanjutkan uji pewarnaan Gram, uji oksidase, uji katalase, dan uji biokimiawi. Setelah itu dilakukan deteksi gen aerolysin menggunakan metode Polymerase Chain Reaction (PCR, serta dilakukan uji sensitivitas antibiotik oxytetracycline

  1. Mercury in blood and eggs of the sea turtle Lepidochelys olivacea from a nesting colony in Oaxaca, Mexico.

    Science.gov (United States)

    Páez-Osuna, F; Calderón-Campuzano, M F; Soto-Jiménez, M F; Ruelas-Inzunza, J

    2011-06-01

    Mercury concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico; 25 female turtles were sampled, a total of 250 eggs were collected during the season 2005-2006. Higher concentrations were found in yolk fraction, while in blood and albumen mean levels were below of 0.0010μg g(-1) dry wt. On the basis of one nesting season, the maternal transfer of Hg via eggs-laying was estimated in 2.0±1.1%. According to international norms, the health of this population and its habitats is acceptable for Hg and corresponds to baseline levels of a nearly pristine environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. The use of spirometry to evaluate pulmonary function in olive ridley sea turtles (Lepidochelys olivacea) with positive buoyancy disorders.

    Science.gov (United States)

    Schmitt, Todd L; Munns, Suzanne; Adams, Lance; Hicks, James

    2013-09-01

    This study utilized computed spirometry to compare the pulmonary function of two stranded olive ridley sea turtles (Lepidochelys olivacea) presenting with a positive buoyancy disorder with two healthy captive olive ridley sea turtles held in a large public aquarium. Pulmonary function test (PFT) measurements demonstrated that the metabolic cost of breathing was much greater for animals admitted with positive buoyancy than for the normal sea turtles. Positively buoyant turtles had higher tidal volumes and significantly lower breathing-frequency patterns with significantly higher expiration rates, typical of gasp-type breathing. The resulting higher energetic cost of breathing in the diseased turtles may have a significant impact on their long-term survival. The findings represent a method for clinical respiratory function analysis for an individual animal to assist with diagnosis, therapy, and prognosis. This is the first study, to our knowledge, to evaluate objectively sea turtles presenting with positive buoyancy and respiratory disease using pulmonary function tests.

  3. Histological and ultrastructural study of the lingual epithelium of the juvenile Pacific ridley turtle, Lepidochelys olivacea (Chelonia, Cheloniidae).

    Science.gov (United States)

    Iwasaki, S; Wanichanon, C; Asami, T

    1996-06-01

    Histological and ultrastructural studies ot the dorsal lingual epithelium of the juvenile Pacific ridley turtle, Lepidochelys olivacea, were performed by light and electron microscopy, and the results were compared to those of freshwater turtles in order to clarify the relationship between the histological and cellular differences of the lingual epithelium and the habitat of the turtles. The tongue of the juvenile Pacific ridley turtle is triangular with a round apex when viewed from above, but it appears flattened in lateral view. Scanning electron microscopy (SEM) revealed no lingual papillae on the dorsal surface of the tongue. Instead, transverse plicae are found on the surface of the body and the radix. The surface of the apex is smooth. Microridge-like structures are present on the surfaces of the cells, and the cell margins are thickened. The mucosal epithelium is keratinized, stratified squamous with a relatively thick layer of desquamating cells. Cells of the basal and deep intermediate layers appear elliptical in shape; and their nuclei are elliptical and centrally located. Numerous desmosomes join the processes of adjacent cells; and hemidesmosomes anchor the basal cells to the basal lamina. The cytoplasm of these cells contains mitochondria, free ribosomes, rough endoplasmic reticulum, vacuoles, and bundles of tonofilaments. Cells and their nuclei in the intermediate layer display gradual flattening. In the shallow intermediate layer, the cells are significantly flattened, with nuclei condensed or absent. The cytoplasm contains many tonofibrils or bundles of tonofilaments, free ribosomes and keratohyalin granules, with numerous ribosomes attached to their surfaces. A few collapsed mitochondria are visible. Cell membranes of the shallow intermediate cells are smooth and attached to those of adjacent cells by desmosomes. The keratinized layer is located on top of the shallow intermediate layer, and consists of significantly flattened cells lacking nuclei

  4. Metals and metalloids in whole blood and tissues of Olive Ridley turtles (Lepidochelys olivacea) from La Escobilla Beach (Oaxaca, Mexico)

    International Nuclear Information System (INIS)

    Cortés-Gómez, Adriana A.; Fuentes-Mascorro, Gisela; Romero, Diego

    2014-01-01

    Highlights: • We evaluate the concentrations of inorganic pollutants in Olive Ridley turtles. • Information can be used to monitoring the pollutants in habitats of sea turtles. • The renal cadmium levels is the highest ever reported worldwide for any sea turtle species. • Pb levels have declined in recent years in this population. - Abstract: Concentrations of eight metals and metalloids (Pb, Cd, Cu, Zn, Mn, Se, Ni and As) were evaluated from 41 nesting females (blood) and 13 dead (tissues) Olive Ridley turtles (Lepidochelys olivacea), a species classified as vulnerable and also listed in Appendix I of the Convention of International Trade in Endangered Species (CITES). The mean blood, liver and kidney lead concentration were 0.02 ± 0.01, 0.11 ± 0.08 and 0.06 ± 0.03 μg g −1 ww respectively, values lower than other turtle species and locations, which it could be due to the gradual disuse of leaded gasoline in Mexico and Central America since the 1990s. Mean concentration of cadmium was 0.17 ± 0.08 (blood), 82.88 ± 36.65 (liver) and 150.88 ± 110.99 μg g −1 (kidney). To our knowledge, the mean renal cadmium levels found is the highest ever reported worldwide for any sea turtle species, while other six elements showed a concentration similar to other studies in sea turtles

  5. Phylogeography of olive ridley turtles (Lepidochelys olivacea) on the east coast of India: implications for conservation theory.

    Science.gov (United States)

    Shanker, K; Ramadevi, J; Choudhury, B C; Singh, L; Aggarwal, R K

    2004-07-01

    Orissa, on the east coast of India, is one of the three mass nesting sites in the world for olive ridley turtles (Lepidochelys olivacea). This population is currently under threat as a result of fishery-related mortality; more than 100 000 olive ridleys have been counted dead in the last 10 years in Orissa. In general, the globally distributed olive ridley turtle has received significantly less conservation attention than its congener, the Kemp's ridley turtle (L. kempi), because the latter is recognized as a distinct species consisting of a single endangered population. Our study of mitochondrial DNA haplotypes suggests that the ridley population on the east coast of India is panmictic, but distinct from all other populations including Sri Lanka. About 96% of the Indian population consisted of a distinct 'K' clade with haplotypes not found in any other population. Nested clade analysis and conventional analysis both supported range expansions and/or long-distance colonization from the Indian Ocean clades to other oceanic basins, which suggested that these are the ancestral source for contemporary global populations of olive ridley turtles. These data support the distinctiveness of the Indian Ocean ridleys, suggesting that conservation prioritization should be based on appropriate data and not solely on species designations.

  6. 17β-Estradiol modulates cell proliferation of medullary cords during ovarian differentiation of the Lepidochelys olivacea sea turtle.

    Science.gov (United States)

    Díaz-Hernández, Verónica; Vázquez-Gómez, Alma; Marmolejo-Valencia, Alejandro; Montaño, Luis Manuel; Merchant-Larios, Horacio

    2017-11-15

    In turtles undergoing temperature sex determination (TSD), bipotential gonads express Sox9 in medullary cords at both female- (FPT) and male-producing temperatures (MPT). Subsequently, when the sex fate of medullary cords becomes dimorphic, at FPT, Sox9 is downregulated, whereas at MPT, its expression is maintained. Medullary cords in the ovary turn into ovarian lacuna, whereas in the testis they differentiate as seminiferous cords. When embryos of Lepidochelys olivacea sea turtle are incubated at MPT and treated with estradiol, Sox9 expression persists in the medullary cords in the form of tiny ovotestis-like formations. The perturbed development of the treated gonads is due to a significant decrease in the number of proliferating cells. This suggests that the disturbed effect caused by exogenous estradiol may be due to a conflict between the gene networks regulated by temperature and the increased level of endogenous estrogens, induced by the treatment. Here, we decided to use fadrozole and fulvestrant, an aromatase inhibitor and an estrogen-receptor antagonist, respectively, to provide insights into the role played by endogenous estrogens in regulating the cell proliferation of the two main gonadal compartments: the medullary cords and the cortex. Comparing cell proliferation patterns, our current results suggest that the endogenous estrogens are involved in determining the sex fate of medullary cords, by repressing proliferation. Interestingly, our results showed that endogenous estradiol levels are unnecessary for the thickening of the ovarian cortex. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Differential expression of SOX9 in gonads of the sea turtle Lepidochelys olivacea at male- or female-promoting temperatures.

    Science.gov (United States)

    Moreno-Mendoza, N; Harley, V R; Merchant-Larios, H

    1999-11-01

    In mouse and chick embryos, the SOX9 gene is down-regulated in genetic females whereas in genetic males it remains in the Sertoli cells. We studied the distribution of SOX9 protein in developing genital ridges of embryos of the sea turtle Lepidochelys olivacea incubated at male- or female-promoting temperatures, using the antibody for detection. At stages 22-24, cells in medullary cords show SOX9 positive nuclei, while coelomic epithelial cells appear negative. At stage 25 however, most medullary cells are SOX9 negative and at the female-promoting temperature, and from stage 26 onwards, SOX9 protein is not detected. At the male-promoting temperature, medullary cords remain SOX9-positive at all stages. These results suggest that SOX9 is up-regulated in Sertoli cells irrespective of primary sex-determining switch. Sex is irreversibly determined at stage 24 or 26 at the male- or female-promoting temperature, respectively (Merchant-Larios et al.,'97). The present results suggest that there is a correlation between SOX9 expression and sex determination in the olive ridley. At the male-promoting temperature, Sertoli cells expressing SOX9 become committed at stage 24 and male sex is determined, whereas at the female-promoting temperature, SOX9 is down-regulated at stage 26 and female sex is determined. J. Exp. Zool. 284:705-710, 1999. Copyright 1999 Wiley-Liss, Inc.

  8. Systemic mycosis caused by Trichophyton spp. in an olive ridley sea turtle (Lepidochelys olivacea): an immunohistochemical study.

    Science.gov (United States)

    Oros, J; Calabuig, P; Arencibia, A; Camacho, M; Jensen, He

    2011-03-01

    A sub-adult female olive ridley sea turtle (Lepidochelys olivacea) was found floating off the coast of Gran Canaria, Canary Islands, Spain. The turtle was lethargic and weak, and died one day after it was found. Necropsy was performed and selected samples of lung and liver were routinely processed for histopathological and immunohistological studies. Grossly, round, ulcerative lesions were observed on the rear flippers. The liver, spleen, coelomic wall, gastric serosa, lungs and urinary bladder were covered by various amounts of fibrin and small granulomas. Histopathologically, a severe fibrinous and granulomatous polyserositis (liver, spleen, stomach, urinary bladder, coelomic wall), severe fibrinous pleuritis and severe multifocal granulomatous pneumonia were diagnosed. Numerous fungal hyphae were observed associated with the lesions. Specific monoclonal and heterologously absorbed polyclonal antibodies served as the primary reagents for identification of aspergillosis, candidiasis, fusariosis, geotricosis, dermatophytosis, scedosporiosis, and zygomycosis. All hyphae were identified as Trichophyton spp., because a strong and uniform reactivity was obtained only with an heterologously absorbed polyclonal antibody raised against somatic antigens of Trichophyton spp. Systemic mycosis caused by Trichophyton spp. There are no known previous reports of Trichophyton spp. causing skin disease or systemic mycotic infection in sea turtles. The usefulness of immunohistochemistry for identifying fungi in sea turtles is reinforced.

  9. Multiple paternity and female-biased mutation at a microsatellite locus in the olive ridley sea turtle (Lepidochelys olivacea).

    Science.gov (United States)

    Hoekert, W E J; Neuféglise, H; Schouten, A D; Menken, S B J

    2002-08-01

    Multiple paternity in the olive ridley sea turtle (Lepidochelys olivacea) population nesting in Suriname was demonstrated using two microsatellite loci, viz., Ei8 and Cm84. The large number of offspring sampled per clutch (70 on average, ranging from 15 to 103) and the number of alleles found at the two loci (18 and eight alleles, respectively) enabled unambiguous assessment of the occurrence of multiple paternity. In two out of 10 clutches analysed, the offspring had been sired by at least two males, which was confirmed at both loci. In both clutches, unequal paternity occurred: 73% and 92% of the offspring had been sired by the primary male. The probability of detecting multiple paternity was 0.903, and therefore there is a small chance that multiple paternity occurred but remained undetected in some of the eight clutches that appeared to be singly sired. Analysis of 703 offspring revealed a high mutation rate for locus Ei8 (micro = 2.3 x 10(-2)) with all 33 mutations occurring in maternal alleles. In particular, one allele of 274 bp mutated at a high frequency in a clutch to which the mother contributed the allele, but in another clutch where the father contributed the same allele, no such mutations were observed. Inferred allele-specific mutation rates for Ei8 and expected numbers of mutations per clutch confirmed that maternal alleles for Ei8 are more likely to mutate in the olive ridley sea turtle than paternal alleles. Possible explanations are discussed.

  10. Metals and metalloids in whole blood and tissues of Olive Ridley turtles (Lepidochelys olivacea) from La Escobilla Beach (Oaxaca, Mexico).

    Science.gov (United States)

    Cortés-Gómez, Adriana A; Fuentes-Mascorro, Gisela; Romero, Diego

    2014-12-15

    Concentrations of eight metals and metalloids (Pb, Cd, Cu, Zn, Mn, Se, Ni and As) were evaluated from 41 nesting females (blood) and 13 dead (tissues) Olive Ridley turtles (Lepidochelys olivacea), a species classified as vulnerable and also listed in Appendix I of the Convention of International Trade in Endangered Species (CITES). The mean blood, liver and kidney lead concentration were 0.02 ± 0.01, 0.11 ± 0.08 and 0.06 ± 0.03 μ gg(-1) ww respectively, values lower than other turtle species and locations, which it could be due to the gradual disuse of leaded gasoline in Mexico and Central America since the 1990s. Mean concentration of cadmium was 0.17 ± 0.08 (blood), 82.88 ± 36.65 (liver) and 150.88 ± 110.9 9μg g(-1) (kidney). To our knowledge, the mean renal cadmium levels found is the highest ever reported worldwide for any sea turtle species, while other six elements showed a concentration similar to other studies in sea turtles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Estructura de tallas de tortuga pico de loro Lepidochelys olivacea (Testudines: Cheloniidae en Tumbes, Perú

    Directory of Open Access Journals (Sweden)

    Manuel Vera

    2012-11-01

    Full Text Available En el presente trabajo se analizó la estructura de tallas de ejemplares de tortuga pico de loro Lepidochelys olivacea, varados y capturados incidentalmente en las playas de Tumbes, Perú (3º38’9,5”S – 80º36’2,48”W y 3º57’21,3”S – 80º57’45,72”W, desde noviembre de 2006 a octubre de 2011. El área de estudio se dividió en tres zonas contiguas, limitadas por las quebradas más activas (Bocapán, El Rubio y Peña Negra. Se registraron 39 ejemplares (74,4% varados y 25,6% capturados incidentalmente, cuyas tallas variaron de 45 a 75 cm LCC (62,5±5,7 cm LCC. El 64,1% correspondió a individuos sub-adultos (<65 cm LCC; n= 25. Espacialmente la mayor cantidad de registros ocurrieron en las zonas 3 y 2, en las cuales porcentajes superiores al 60% se consideraron sub-adultos; mientras que en la zona 1, el 83% fue adulto. Temporalmente en la época lluviosa se registró la mayoría de las observaciones (59%, en la cual el 78,3% de ejemplares se consideró sub–adulto; siendo mayor que en la época seca (43,8%. Las tallas presentaron diferencias significativas entre zonas y épocas climáticas. Se corroboró el patrón de distribución latitudinal por estados de madurez aparente (más adultos en el norte. La presencia del componente adulto indicaría que el litoral de Tumbes sería una potencial zona de anidamiento de L. olivacea, con mayores probabilidades de ovoposición en época seca, corroborada por los eventos de anidamiento recientes.

  12. Nesting ecology of the olive ridley sea turtle (Lepidochelys olivacea) (Cheloniidae) at el Valle Beach, northern pacific, Colombia

    International Nuclear Information System (INIS)

    Karla G Barrientos Munoz; Cristian Ramirez Gallego; Vivian Paez

    2014-01-01

    The olive ridley (Lepidochelys olivacea) is the most common sea turtle to nest in Colombia. El valle beach is considered the most important nesting beach for this species in South America. Intensive direct capture of nesting females and egg poaching for consumption and local commercial purposes has been a common practice for years. We conducted an analysis of the nesting ecology of the olive ridley on el valle beach in the northern pacific of Colombia in 2008. A total of 164 clutches were transferred to an artificial hatchery for protection. The peak of nesting occurred from the second half of August until the end of September, accounting for 64.6 % of all nests. Along the beach, the section most frequently used was section 3, with 26 % of the nests. The nests were laid mainly in zone 3.69 %. We encountered 55 nesting females and marked 46 of them. Mean CCL was 64.9 ± 2.4 cm and mean CCW was 68.6 ± 2.6 cm. females laid on average of 87.3 ± 14.2 eggs per clutch. We recorded two nesting events per female, with a mean inter-nesting period of 18.8 ± 4.2 days. The reproductive output for the season was 181.5 ± 34.8 eggs / female. Mean hatching success was 81.1 ± 12.1 % and mean emergence success was 77.6 ± 12.7 %. The incubation period was 65 ± 4.7 days. Our study is a valuable contribution to knowledge of the reproductive ecology of the olive ridley population regionally and globally.

  13. Timing of SOX9 downregulation and female sex determination in gonads of the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Torres-Maldonado, L; Moreno-Mendoza, N; Landa, A; Merchant-Larios, H

    2001-09-15

    The SRY-related gene SOX9 is involved in the differentiation of Sertoli cells in male gonads of vertebrates with different kinds of sex determination. In the olive ridley Lepidochelys olivacea, a species with temperature sex determination (TSD), the SOX9 protein is expressed at stages 21-24 in medullary cells in gonads of embryos incubated at both male-(MPT) or female-promoting temperatures (FPT). However, at FPT the expression of SOX9 protein decreases at stage 25 and disappears at stage 26, suggesting this as the critical period for SOX9 regulation by temperature. Here, we used reverse transcriptase polymerase chain reaction (RT-PCR) to detect SOX9 transcripts in gonads of embryos switched from MPT to FPT at stage 23 and sampled at days 6-14. Simultaneously, groups of embryos were switched back to MPT and gonadal sex was established. SOX9 transcripts were detected at days 6-12 of switching, when embryos reached stage 25 and were no longer detected at day 14, when the embryos were at stage 26. Embryos switched back to MPT at days 6 or 8 formed testes, whereas embryos switched at days 10 or 14 developed ovaries. Results suggest that at MPT the male sex-determining pathway that maintains SOX9 expression in male gonads is established at stage 24. In contrast, at FPT, the female sex-determining pathway involved in downregulation of SOX9 in female gonads occurs within two days at stage 25. J. Exp. Zool. 290:498-503, 2001. Copyright 2001 Wiley-Liss, Inc.

  14. Diatoms and Other Epibionts Associated with Olive Ridley (Lepidochelys olivacea) Sea Turtles from the Pacific Coast of Costa Rica.

    Science.gov (United States)

    Majewska, Roksana; Santoro, Mario; Bolaños, Federico; Chaves, Gerardo; De Stefano, Mario

    2015-01-01

    Although the sea turtles have long been familiar and even iconic to marine biologists, many aspects of their ecology remain unaddressed. The present study is the first of the epizoic diatom community covering the olive ridley turtle's (Lepidochelys olivacea) carapace and the first describing diatoms living on sea turtles in general, with the primary objective of providing detailed information on turtle epibiotic associations. Samples of turtle carapace including the associated diatom biofilm and epizoic macro-fauna were collected from Ostional beach (9° 59´ 23.7´´ N 85° 41´ 52.6´´ W), Costa Rica, during the arribada event in October 2013. A complex diatom community was present in every sample. In total, 11 macro-faunal and 21 diatom taxa were recorded. Amongst diatoms, the most numerous were erect (Achnanthes spp., Tripterion spp.) and motile (Haslea sp., Navicula spp., Nitzschia spp., Proschkinia sp.) forms, followed by adnate Amphora spp., while the most common macro-faunal species was Stomatolepas elegans (Cirripedia). Diatom densities ranged from 8179 ± 750 to 27685 ± 4885 cells mm-2. Epizoic microalgae were either partly immersed or entirely encapsulated within an exopolymeric coat. The relatively low diatom species number, stable species composition and low inter-sample dissimilarities (14.4% on average) may indicate a mutualistic relationship between the epibiont and the basibiont. Dispersal of sea turtle diatoms is probably highly restricted and similar studies will help to understand both diatom diversity, evolution and biogeography, and sea turtle ecology and foraging strategies.

  15. Diatoms and Other Epibionts Associated with Olive Ridley (Lepidochelys olivacea Sea Turtles from the Pacific Coast of Costa Rica.

    Directory of Open Access Journals (Sweden)

    Roksana Majewska

    Full Text Available Although the sea turtles have long been familiar and even iconic to marine biologists, many aspects of their ecology remain unaddressed. The present study is the first of the epizoic diatom community covering the olive ridley turtle's (Lepidochelys olivacea carapace and the first describing diatoms living on sea turtles in general, with the primary objective of providing detailed information on turtle epibiotic associations. Samples of turtle carapace including the associated diatom biofilm and epizoic macro-fauna were collected from Ostional beach (9° 59´ 23.7´´ N 85° 41´ 52.6´´ W, Costa Rica, during the arribada event in October 2013. A complex diatom community was present in every sample. In total, 11 macro-faunal and 21 diatom taxa were recorded. Amongst diatoms, the most numerous were erect (Achnanthes spp., Tripterion spp. and motile (Haslea sp., Navicula spp., Nitzschia spp., Proschkinia sp. forms, followed by adnate Amphora spp., while the most common macro-faunal species was Stomatolepas elegans (Cirripedia. Diatom densities ranged from 8179 ± 750 to 27685 ± 4885 cells mm-2. Epizoic microalgae were either partly immersed or entirely encapsulated within an exopolymeric coat. The relatively low diatom species number, stable species composition and low inter-sample dissimilarities (14.4% on average may indicate a mutualistic relationship between the epibiont and the basibiont. Dispersal of sea turtle diatoms is probably highly restricted and similar studies will help to understand both diatom diversity, evolution and biogeography, and sea turtle ecology and foraging strategies.

  16. Diatoms and Other Epibionts Associated with Olive Ridley (Lepidochelys olivacea) Sea Turtles from the Pacific Coast of Costa Rica

    Science.gov (United States)

    Majewska, Roksana; Santoro, Mario; Bolaños, Federico; Chaves, Gerardo; De Stefano, Mario

    2015-01-01

    Although the sea turtles have long been familiar and even iconic to marine biologists, many aspects of their ecology remain unaddressed. The present study is the first of the epizoic diatom community covering the olive ridley turtle’s (Lepidochelys olivacea) carapace and the first describing diatoms living on sea turtles in general, with the primary objective of providing detailed information on turtle epibiotic associations. Samples of turtle carapace including the associated diatom biofilm and epizoic macro-fauna were collected from Ostional beach (9° 59´ 23.7´´ N 85° 41´ 52.6´´ W), Costa Rica, during the arribada event in October 2013. A complex diatom community was present in every sample. In total, 11 macro-faunal and 21 diatom taxa were recorded. Amongst diatoms, the most numerous were erect (Achnanthes spp., Tripterion spp.) and motile (Haslea sp., Navicula spp., Nitzschia spp., Proschkinia sp.) forms, followed by adnate Amphora spp., while the most common macro-faunal species was Stomatolepas elegans (Cirripedia). Diatom densities ranged from 8179 ± 750 to 27685 ± 4885 cells mm-2. Epizoic microalgae were either partly immersed or entirely encapsulated within an exopolymeric coat. The relatively low diatom species number, stable species composition and low inter-sample dissimilarities (14.4% on average) may indicate a mutualistic relationship between the epibiont and the basibiont. Dispersal of sea turtle diatoms is probably highly restricted and similar studies will help to understand both diatom diversity, evolution and biogeography, and sea turtle ecology and foraging strategies. PMID:26083535

  17. Molecular oxidative stress markers in olive ridley turtles (Lepidochelys olivacea) and their relation to metal concentrations in wild populations.

    Science.gov (United States)

    Cortés-Gómez, Adriana A; Morcillo, Patricia; Guardiola, Francisco A; Espinosa, Cristobal; Esteban, María A; Cuesta, Alberto; Girondot, Marc; Romero, Diego

    2018-02-01

    Due to their longevity and extensive migration areas, marine turtles are able to accumulate diverse contaminants over many years and as a consequence they represent an interesting bioindicator species for marine ecosystem pollution. Metals provoke toxicological effects in many aquatic animal species, but marine turtles have been under-investigated in this area. Thus, we have determined the presence of certain inorganic elements (As, Cd, Cu, Ni, Pb, Se and Zn) in olive ridley turtles (Lepidochelys olivacea) and related them to metallothionein (MT), superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) transcription and/or enzymatic activities. Gene expression of sod, cat and gr was found to be higher in blood than liver or kidney but most of the significant relationships were found in liver, not only for gene expression but also for enzyme activities. This must be related to the role the liver has as the first filter organ. Several positive relationships of sod, cat and gr gene expression in the different tissues were found in this population, as well as very high Cd concentrations. This could mean that these turtles are adapting to the metals-production of ROS and damage through a high transcription of these antioxidants. Multiple positive relationships with GR seem to be part of its compensatory effect due to the decrease of SOD production against the high and chronic exposure to certain xenobiotics. CAT, on the other hand, seems not to be used much, and glutathione detoxification of H 2 O 2 may be more important in this species. Finally, despite the very high Cd concentrations found in this population, no significant relationship was found in any tissue with metallothionein gene expression. These results, along with very high Cd concentrations and a negative relationship with Cu, lead us to consider some kind of disruption in mt gene expression in these turtles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Formation of the genital ridges is preceded by a domain of ectopic Sox9-expressing cells in Lepidochelys olivacea.

    Science.gov (United States)

    Díaz-Hernández, Verónica; Marmolejo-Valencia, Alejandro; Harfush, Martha; Merchant-Larios, Horacio

    2012-01-01

    Bipotential gonads represent the structural framework from which alternative molecular sex determination networks have evolved. Maintenance of Sox9 expression in Sertoli cells is required for the structural and functional integrity of male gonads in mammals and probably in most amniote vertebrates. However, spatial and temporal patterns of Sox9 expression have diversified along evolution. Species with temperature sex determination are an interesting predictive model since one of two alternative developmental outcomes, either ovary or testis occurs under controlled laboratory conditions. In the sea turtle Lepidochelys olivacea, Sox9 is expressed in the medullary cords of bipotential gonads when incubated at both female- or male-promoting temperature (FT or MT). Sox9 is then turned off in presumptive ovaries, while it remains turned on in testes. In the current study, Sox9 was used as a marker of the medullary cell lineage to investigate if the medullary cords originate from mesothelial cells at the genital ridges where Sox9 is upregulated, or, if they derive from a cell population specified at an earlier developmental stage, which maintains Sox9 expression. Using immunofluorescence and in situ hybridization, embryos were analyzed prior to, during and after gonadal sex determination. A T-shaped domain (T-Dom) formed by cytokeratin (CK), N-cadherin (Ncad) and SOX9-expressing cells was found at the upper part of the hindgut dorsal mesentery. The arms of the T-Dom were extended to both sides towards the ventromedial mesonephric ridge before the thickening of the genital ridges, indicating that they contained gonadal epithelial cell precursors. Thereafter, expression of Sox9 was maintained in medullary cords while it was downregulated at the surface epithelium of bipotential gonads in both FT and MT. This result contrasts with observations in mammals and birds, in which Sox9 upregulation starts at a later stage in the inner cells underlying the Sox9-negative surface

  19. NESTING ECOLOGY OF THE OLIVE RIDLEY SEA TURTLE (Lepidochelys olivacea (CHELONIIDAE AT EL VALLE BEACH, NORTHERN PACIFIC, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Karla G. Barrientos-Muñoz

    2014-09-01

    Full Text Available En Colombia, la tortuga golfina (Lepidochelys olivacea es la más común de las tortugas anidantes. La playa El Valle es considerada la más importante para anidación en Suramérica. La intensa captura de hembras y saqueo de huevos para consumo y comercio local ha sido una práctica común por años. Realizamos un análisis de la ecología de anidación de la tortuga golfina en la Playa El Valle, Pacifico Norte, durante la temporada de 2008. Un total de 164 nidadas fueron transferidas a viveros de protección. El pico de anidación ocurrió durante la segunda quincena de agosto y septiembre con un 64,63 % de las posturas. A lo largo de la playa, el sector 3 presento la mayor frecuencia de anidación con 26 %. Los nidos fueron desovados principalmente en la zona 3, con 69 %. Encontramos 55 hembras y 46 fueron marcadas. El LCC fue (promedio± DE: 64,9 ± 2,4 cm y ACC fue (promedio ± DE: 68,6 ± 2,6 cm. Las hembras desovaron 87,3 ± 14,2 huevos por nidada. Registramos dos eventos de anidación por hembra, con un intervalo de (promedio ± DE: 18,8 ± 4,2 días. El producto reproductivo fue (promedio ± DE: 181,5 ± 34,8 huevos por hembra. El promedio en éxito de eclosión fue 81,1 ±12,1 % y de emergencia 77,6 ± 12,7 %. El período de incubación fue (promedio ± DE: 65 ± 4,7 días. Nuestros datos son una valiosa contribución al conocimiento de la ecología reproductiva de la población de tortugas golfina regional y globalmente.

  20. The sea-finding behavior of hatchling olive ridley sea turtles, Lepidochelys olivacea, at the beach of San Miguel (Costa Rica)

    Science.gov (United States)

    Stapput, Katrin; Wiltschko, Wolfgang

    2005-05-01

    Newly hatched olive ridley sea turtles (Lepidochelys olivacea) were tested for their directional preferences in a sand-filled circular arena in total darkness. Hatchlings that had crawled about 5 m on the beach, toward the sea preferred the southwesterly direction that would have brought them to the water line, whereas hatchlings that had been denied this experience headed eastward, a direction of unclear origin. These data suggest that a short crawl across the natural beach can set the direction in which the young turtles subsequently move. The crawling experience was sufficient to acquire the compass course that they later follow, probably with the help of a magnetic compass, not only in the water, but already while still on land.

  1. Metal contents of marine turtle eggs (Chelonia mydas; Lepidochelys olivacea) from the tropical eastern pacific and the implications for human health.

    Science.gov (United States)

    Ross, David A; Guzmán, Héctor M; Van Hinsberg, Vincent J; Potvin, Catherine

    2016-10-02

    Concentrations of eight elements were measured in Chelonia mydas and Lepidochelys olivacea eggs collected along the Pacific coast of Panama. Manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and mercury (Hg) concentrations were similar to previous reports of these species from around the world, while lead (Pb) was lower than previous reports. Cd posed the highest health risk to people who regularly eat the eggs, with average consumption rates leading to target hazard quotients (THQ) of up to 0.35 ± 0.15. Our conclusions indicate that current turtle egg consumption in isolated, coastal Pacific communities may pose a health concern for young children, and that youth and young adults should limit their consumption of turtle eggs to reduce their total intake of nonessential metals.

  2. The sea-finding behavior of hatchling olive ridley sea turtles, Lepidochelys olivacea, at the beach of San Miguel (Costa Rica).

    Science.gov (United States)

    Stapput, Katrin; Wiltschko, Wolfgang

    2005-05-01

    Newly hatched olive ridley sea turtles (Lepidochelys olivacea) were tested for their directional preferences in a sand-filled circular arena in total darkness. Hatchlings that had crawled about 5 m on the beach, toward the sea preferred the southwesterly direction that would have brought them to the water line, whereas hatchlings that had been denied this experience headed eastward, a direction of unclear origin. These data suggest that a short crawl across the natural beach can set the direction in which the young turtles subsequently move. The crawling experience was sufficient to acquire the compass course that they later follow, probably with the help of a magnetic compass, not only in the water, but already while still on land.

  3. Penetración de vibrio mimicus a través de la cáscara del huevo de tortuga lora (lepidochelys olivacea)

    OpenAIRE

    M\\u00F3nica Pereira-Zamora; Francisco Hern\\u00E1ndez-Chavarr\\u00EDa; Eric Wong-Gonz\\u00E1lez

    2007-01-01

    Penetración de Vibrio mimicus a través de la cáscara del huevo de tortuga lora (Lepidochelys olivacea). El objetivo de esta investigación consistió en determinar la capacidad de penetración del Vibrio mimicus a través de la cáscara del huevo. La investigación se realizó en el Centro Nacional de Ciencia y Tecnología de Alimentos en el año 2000. Se inoculó la superfi cie de la cáscara con la bacteria y se procedió a incubar las muestras por 72 horas a 25°C. Después de este período se observaron...

  4. Acetylcholinesterase-positive innervation is present at undifferentiated stages of the sea turtle Lepidochelis olivacea embryo gonads: implications for temperature-dependent sex determination.

    Science.gov (United States)

    Gutiérrez-Ospina, G; Jiménez-Trejo, F J; Favila, R; Moreno-Mendoza, N A; Granados Rojas, L; Barrios, F A; Díaz-Cintra, S; Merchant-Larios, H

    1999-07-19

    In embryos of different reptile species, incubation temperature triggers a cascade of endocrine events that lead to gonad sex differentiation. The cellular and molecular mechanisms by which temperature sets in motion this process are still controversial. Here, we begin evaluating the possible participation of the nervous system in temperature-dependent sex determination by showing the existence and origin of acetylcholinesterase (AchE)-positive nerve fibers in undifferentiated gonads of the Lepidochelys olivacea (L. olivacea) sea turtle putative male and female embryos, along the thermosensitive period for sex determination (TPSD; stages 20-27). AChE-positive nerve bundles and fibers were readily visualized until developmental stage 24 and thereafter. DiI injections and confocal imaging showed that some of these gonadal nerves arise from the lower thoracic and upper lumbar spinal cord levels, and might thus be sensory in nature. Because the vertebrate spinal cord is capable of integrating by itself thermoregulatory responses with no intervention of uppermost levels of the central nervous system, we also evaluated spinal cord maturation during the TPSD. The maturation of the spinal cord was more advanced in putative female than in male embryos, when sex determination is taking place for each sex; this process starts and ends earlier in male than in female embryos. Together these observations open the possibility that the spinal cord and the innervation derived from it could play a direct role in driving or modulating the process of temperature-dependent gonad sex determination and/or differentiation, particularly in female L. olivacea embryos.

  5. Expression profiles of Dax1, Dmrt1, and Sox9 during temperature sex determination in gonads of the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Torres Maldonado, L C; Landa Piedra, A; Moreno Mendoza, N; Marmolejo Valencia, A; Meza Martínez, A; Merchant Larios, H

    2002-10-15

    Sex determination is controlled either by genetic or environmental factors. In mammals Sry initiates determination but no homologue of this gene exists in non-mammalian species. Other genes of the mammalian sex-determining pathway have been identified in gonads of different vertebrates. Sox9, Dax1, and Dmrt1 are expressed at the onset of gonadal development in birds and reptiles. In the sea turtle Lepidochelys olivacea, a species with temperature sex determination (TSD), Sox9 is expressed in undifferentiated gonads at male- (MPT) or female-promoting temperatures (FPT). At MPT, Sox9 remains expressed in male gonads, but at FPT it is downregulated coinciding with the onset of the ovarian morphologic differentiation and female sex determination. At MPT however, male sex is determined early than at FPT in still undifferentiated gonads suggesting that other genes maintain Sox9 expression in testis. Here we used RT-PCR to study the expression profiles of Dax1, Dmrt1, and Sox9 in gonads of embryos of L. olivacea incubated at MPT or at FPT. The profiles were correlated with sex determination during and after the temperature-sensitive period (TSP). Dax1 maintained similar levels at both temperatures during the TSP. The Dax1 expression level increased significantly in ovaries compared to testes at stage 27, once they were morphologically distinct. The expression levels of Dmrt1 were higher at MPT than at FPT at all stages, in contrast with Sox9 levels which were similar at both temperatures at stages 23-25. Together, current results suggest that, whereas Dax1 is not involved in TSD in L. olivacea, upregulation of Dmrt1 and downregulation of Sox9 may play a role in male and female sex determination, respectively.

  6. Response of diencephalon but not the gonad to female-promoting temperature with elevated estradiol levels in the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Salame-Mendez, A; Herrera-Munoz, J; Moreno-Mendoza, N; Merchant-Larios, H

    1998-03-01

    Although temperature sex determination is well known in several reptile species, the physiological mechanism underlying this process remains to be elucidated. In the current work, we analyzed the levels of testosterone (T) and estradiol (E2) in the gonads; two brain regions--telencephalon (Te) and diencephalon/mesencephalon (Di)--and the serum of developing embryos of the olive ridley Lepidochelys olivacea incubated at male- or female-promoting temperatures. Conversion of pregnenolone (P5) to T and T to E2 were studied in the gonads and brain. The analyses were performed during three periods: the thermosensitive period (TSP), histologically undifferentiated gonads (UDG), and differentiated gonads (DG). In the gonads, serum, and brain, T concentrations were higher at the female-promoting temperature during the three periods, whereas in the gonads and serum, E2 levels were similar at the female and male-promoting temperature. In Di, the concentration of E2 was significantly higher at the female-promoting temperature. Biotransformation of P5 to T in gonadal tissues were slightly higher at the female-promoting temperature in TSP and increased during UDG and DG. Conversion of T to E2, however, was similar at the two temperatures during the three periods. In the brain, the Di showed a higher efficiency for transforming T to E2 at the female-promoting temperature. Our present results do not allow us to decide whether the diencephalon is the cause or the effect, but they conclusively demonstrate that, in L. olivacea, this region of the brain senses temperature during sex determination.

  7. The influence of oceanographic features on the foraging behavior of the olive ridley sea turtle Lepidochelys olivacea along the Guiana coast

    Science.gov (United States)

    Chambault, Philippine; de Thoisy, Benoît; Heerah, Karine; Conchon, Anna; Barrioz, Sébastien; Dos Reis, Virginie; Berzins, Rachel; Kelle, Laurent; Picard, Baptiste; Roquet, Fabien; Le Maho, Yvon; Chevallier, Damien

    2016-03-01

    The circulation in the Western Equatorial Atlantic is characterized by a highly dynamic mesoscale activity that shapes the Guiana continental shelf. Olive ridley sea turtles (Lepidochelys olivacea) nesting in French Guiana cross this turbulent environment during their post-nesting migration. We studied how oceanographic and biological conditions drove the foraging behavior of 18 adult females, using satellite telemetry, remote sensing data (sea surface temperature, sea surface height, current velocity and euphotic depth), simulations of micronekton biomass (pelagic organisms) and in situ records (water temperature and salinity). The occurrence of foraging events throughout migration was located using Residence Time analysis, while an innovative proxy of the hunting time within a dive was used to identify and quantify foraging events during dives. Olive ridleys migrated northwestwards using the Guiana current and remained on the continental shelf at the edge of eddies formed by the North Brazil retroflection, an area characterized by low turbulence and high micronekton biomass. They performed mainly pelagic dives, hunting for an average 77% of their time. Hunting time within a dive increased with shallower euphotic depth and with lower water temperatures, and mean hunting depth increased with deeper thermocline. This is the first study to quantify foraging activity within dives in olive ridleys, and reveals the crucial role played by the thermocline on the foraging behavior of this carnivorous species. This study also provides novel and detailed data describing how turtles actively use oceanographic structures during post-nesting migration.

  8. Analysis of epibiont data in relation with the Debilitated Turtle Syndrome of sea turtles in Chelonia mydas and Lepidochelys olivacea from Concepción coast, Chile

    Directory of Open Access Journals (Sweden)

    Italo Fernández

    2015-11-01

    Full Text Available Epibionts on the surface of the skin and shell of a specimen of Chelonia mydas and three Lepidochelys olivacea found floating on the coast of Concepción, Chile, between June 2010 and December 2012, were analyzed. These epibionts were analyzed during the clinical inspection and the tissue changes related to its settlement, with filamentous algae around, were observed. Subsequently, the epibionts were identified by morphological observation. The knowledge about theses epibionts in Chile is reviewed and the potential occurrence of Debilitated Turtle Syndrome (DTS in these turtles is discussed. The presence of sea turtles in the Chilean coast is considered a casual event, so there is little information on this issue. We propose it is necessary to carry out more studies on the association between turtles and epibionts because their identification, colonizing reptiles’ surface may give relevant information to a better understanding of different diseases, including DTS, that affect these marine reptiles and facilitates the development of strategies intended to recover their populations.

  9. Hatchlings of the Marine Turtle Lepidochelys olivacea Display Signs of Prenatal Stress at Emergence after Being Incubated in Man-Made Nests: A Preliminary Report

    Directory of Open Access Journals (Sweden)

    Ma. A. Herrera-Vargas

    2017-12-01

    Full Text Available Egg translocation and incubation in man-made nests (MMN are common conservation practices through marine turtle hatcheries worldwide. These measures have been associated with reduced hatching rates, altered hatchling sex ratio, fetal dysmorphic anatomical features, and feeble hatchlings health. Previous studies have shown that MMN and natural nests (NN provide different incubatory conditions. Therefore, incubatory challenges imposed by MMN conditions on fetal development could induce stress responses affecting hatchlings functional morphology later on life. There is no evidence of incubatory stress associated with conservation measures in turtle fetuses or hatchlings. Thus, in this paper we tested the hypothesis that MMN incubation exposes turtle fetuses to stressing conditions. Given that the hypothalamic-pituitary-interrenal axis begins functioning by day 11 of incubation in reptiles, our experiments explored the effects of incubatory conditions, rather than those associated with translocation, on fetal stress responses. We showed that Lepidochelys olivacea hatchlings incubated in MMN displayed reduced body weight, hypertrophic inter-renal glands, testicular hypotrophy and hypotrophic dorso-medial cortical pyramidal neurons, when compared with hatchlings emerging from NN. Furthermore, MMN hatchlings had higher serum levels of corticosterone at emergence, and displayed an attenuated acute stress response after traversing the beach. Therefore, the relocation of nests to protect them could negatively impact the health and survival of sea turtles. Thus, this action should only be undertaken when no alternative is available.

  10. Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: Concentration, isotopic composition and maternal transfer

    International Nuclear Information System (INIS)

    Paez-Osuna, F.; Calderon-Campuzano, M.F.; Soto-Jimenez, M.F.; Ruelas-Inzunza, J.R.

    2010-01-01

    Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the 'arribada' event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95 ± 0.18 μg g -1 ) and egg samples (yolk, 0.80 ± 0.10 μg g -1 ; albumen, 1.08 ± 0.20 μg g -1 ; eggshell, 1.05 ± 0.20 μg g -1 ) were comparable or even lower than those found in other sea turtles. The isotope ratios ( 206 Pb/ 207 Pb and 206 Pb/ 208 Pb) in blood (1.183 ± 0.0006 and 2.452 ± 0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188 ± 0.005 and 2.455 ± 0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.

  11. Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: concentration, isotopic composition and maternal transfer.

    Science.gov (United States)

    Páez-Osuna, F; Calderón-Campuzano, M F; Soto-Jiménez, M F; Ruelas-Inzunza, J R

    2010-03-01

    Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the "arribada" event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95+/-0.18microgg(-1)) and egg samples (yolk, 0.80+/-0.10microg g(-1); albumen, 1.08+/-0.20microg g(-1); eggshell, 1.05+/-0.20microg g(-1)) were comparable or even lower than those found in other sea turtles. The isotope ratios ((206)Pb/(207)Pb and (206)Pb/(208)Pb) in blood (1.183+/-0.0006 and 2.452+/-0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188+/-0.005 and 2.455+/-0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment. Copyright 2009 Elsevier Ltd. All rights reserved.

  12. The Distribution and Conservation Status of Green Turtles (Chelonia mydas) and Olive Ridley Turtles (Lepidochelys olivacea) on Pulau Pinang beaches (Malaysia), 1995–2009

    Science.gov (United States)

    Salleh, Sarahaizad Mohd; Yobe, Mansor; Sah, Shahrul Anuar Mohd

    2012-01-01

    The Green Turtle (Chelonia mydas) and Olive Ridley Turtle (Lepidochelys olivacea) are the only sea turtles with recorded landings in the Pulau Pinang coastal area. The Green Turtle has been the most abundant and widely distributed sea turtle in this area since it was first surveyed in 1995. Statistical analysis by the Pulau Pinang Department of Fisheries on the distribution of sea turtles from 2001 through 2009 has identified Pantai Kerachut and Telok Kampi as the most strongly preferred beaches for Green Turtle landings, with records for almost every month in every year. Green Turtle tracks and nests have also been found along the coast of Pulau Pinang at Batu Ferringhi, Tanjong Bungah, Pantai Medan, Pantai Belanda, Telok Kumbar, Gertak Sanggul, Moonlight Beach, Telok Duyung, Telok Aling, Telok Bahang and Telok Katapang. The Olive Ridley Turtle is present in smaller numbers; landing and nesting have only been recorded on a few beaches. There are no previous records of Olive Ridley landings at Pantai Kerachut and Telok Kampi, but tracks and nests have been found at Telok Kumbar, Tanjong Bungah, Pantai Medan, Telok Duyung and Gertak Sanggul. A Turtle Conservation Centre has been established at Pantai Kerachut to protect these species from extinction in Pulau Pinang. This paper presents details of the records and distribution of sea turtles in Pulau Pinang from 1995 through 2009. PMID:24575226

  13. Hox gene expression in the embryonic genital system of the sea turtle Lepidochelys olivacea (Eschscholt, 1829), a species with temperature-dependent sex determination.

    Science.gov (United States)

    Sifuentes-Romero, Itzel; Merchant-Larios, Horacio; García-Gasca, Alejandra

    2010-09-01

    Hox genes are conserved transcription factors which regulate embryonic morphogenesis and differentiation. For the first time, we examined the quantitative and spatial expression of two Hox 5' genes, HoxD11 and HoxA13, in the developing genital system of the olive ridley Lepidochelys olivacea, a species with temperature-dependent sex determination. Quantitative and spatial expression patterns of both genes suggest a role in the female pathway rather than the male pathway. For instance, both genes, especially HoxA13, were expressed in the undifferentiated gonad during the thermosensitive period at a female promoting temperature, and downregulated in the differentiated gonad. By contrast, expression of both genes was low in gonads incubated at a male promoting temperature and did not change significantly in the differentiated gonad. Furthermore, we found high expression levels of HoxA13 in the paramesonephric duct at the male promoting temperature but not at the female promoting temperature, suggesting a role for this Hox gene in the partial regression of the Müllerian duct in males. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Trace metals (Cd, Cu, Ni, and Zn) in blood and eggs of the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico.

    Science.gov (United States)

    Páez-Osuna, Federico; Calderón-Campuzano, María F; Soto-Jiménez, Martín F; Ruelas-Inzunza, Jorge R

    2010-11-01

    Trace metals (Cd, Cu, Ni, and Zn) concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico. Twenty-five female turtles were sampled, a total of 250 eggs were collected during the "arribada" event of the 2005-2006 season. Zn concentrations were highest in the yolk [72.3 ± 10.9 μg/g dry weight (dw)] and blood (58.4 ± 4.7 μg/g dw), whereas Ni concentrations were highest in the shell (48.5 ± 12.9 μg/g dw). The mean concentrations of Cu, and Cd in the analyzed tissues were lower than those reported in other sea turtle species. However, Zn and Ni concentrations in the yolk and shell, respectively, had the same distribution pattern observed at loggerhead and green turtles. On the basis of one nesting season, the maternal transfer and/or the excretion rates of trace metals via eggs-laying, estimated in terms of metal burdens in whole body, were 0.2, 7.8, 3.4, and 21.5% for Cd, Cu, Zn, and Ni, respectively.

  15. The Distribution and Conservation Status of Green Turtles (Chelonia mydas) and Olive Ridley Turtles (Lepidochelys olivacea) on Pulau Pinang beaches (Malaysia), 1995-2009.

    Science.gov (United States)

    Salleh, Sarahaizad Mohd; Yobe, Mansor; Sah, Shahrul Anuar Mohd

    2012-05-01

    The Green Turtle (Chelonia mydas) and Olive Ridley Turtle (Lepidochelys olivacea) are the only sea turtles with recorded landings in the Pulau Pinang coastal area. The Green Turtle has been the most abundant and widely distributed sea turtle in this area since it was first surveyed in 1995. Statistical analysis by the Pulau Pinang Department of Fisheries on the distribution of sea turtles from 2001 through 2009 has identified Pantai Kerachut and Telok Kampi as the most strongly preferred beaches for Green Turtle landings, with records for almost every month in every year. Green Turtle tracks and nests have also been found along the coast of Pulau Pinang at Batu Ferringhi, Tanjong Bungah, Pantai Medan, Pantai Belanda, Telok Kumbar, Gertak Sanggul, Moonlight Beach, Telok Duyung, Telok Aling, Telok Bahang and Telok Katapang. The Olive Ridley Turtle is present in smaller numbers; landing and nesting have only been recorded on a few beaches. There are no previous records of Olive Ridley landings at Pantai Kerachut and Telok Kampi, but tracks and nests have been found at Telok Kumbar, Tanjong Bungah, Pantai Medan, Telok Duyung and Gertak Sanggul. A Turtle Conservation Centre has been established at Pantai Kerachut to protect these species from extinction in Pulau Pinang. This paper presents details of the records and distribution of sea turtles in Pulau Pinang from 1995 through 2009.

  16. Cloning and expression of the estrogen receptor-alpha (Esr1) from the Harderian gland of the sea turtle (Lepidochelys olivacea).

    Science.gov (United States)

    Chávez, Bertha; Ramos, Luis; Merchant-Larios, Horacio; Vilchis, Felipe

    2009-06-01

    The effects of estradiol on the Harderian gland (HG) are believed to be partially regulated by the transcriptional regulation of the estrogen-related genes via estrogen receptor (ER). In reptiles, however, it has not been well established whether the HG contains or expresses steroid nuclear receptors. As a first step toward investigating the molecular mechanisms of estrogen signalling in the HG, we isolated the cDNA for ERalpha in the sea turtle Lepidochelys olivacea. ERalpha was cloned using RT-PCR coupled with 5' and 3' RACE procedures. The cDNA contains a complete open reading frame encoding 588 amino acid residues. Comparative analysis of this amino acid sequence showed moderate to strong conservation of the ERalpha (Esr1) gene within divergent vertebrate groups. In transfection studies, the cloned ER displayed high affinity K(d)=0.25nM and high specificity for 17beta-estradiol. Binding assays using sucrose density gradients demonstrated a specific 7-7.5 S binding component in the HG cytosolic fractions. RT-qPCR analysis showed significant ERalpha mRNA expression in the liver, HG, lung and brain. Altogether, these results provide evidence for the expression of intracellular ERs in the HG of the sea turtle and suggest that ERalpha may be an important modulator of the estrogen-mediated response in the HG of reptiles.

  17. The characterization of cytosolic glutathione transferase from four species of sea turtles: loggerhead (Caretta caretta), green (Chelonia mydas), olive ridley (Lepidochelys olivacea), and hawksbill (Eretmochelys imbricata).

    Science.gov (United States)

    Richardson, Kristine L; Gold-Bouchot, Gerardo; Schlenk, Daniel

    2009-08-01

    Glutathione s-transferases (GST) play a critical role in the detoxification of exogenous and endogenous electrophiles, as well as the products of oxidative stress. As compared to mammals, GST activity has not been extensively characterized in reptiles. Throughout the globe, most sea turtle populations face the risk of extinction. Of the natural and anthropogenic threats to sea turtles, the effects of environmental chemicals and related biochemical mechanisms, such as GST catalyzed detoxification, are probably the least understood. In the present study, GST activity was characterized in four species of sea turtles with varied life histories and feeding strategies: loggerhead (Caretta caretta), green (Chelonia mydas), olive ridley (Lepidochelys olivacea), and hawksbill (Eretmochelys imbricata). Although similar GST kinetics was observed between species, rates of catalytic activities using class-specific substrates show inter- and intra-species variation. GST from the spongivorous hawksbill sea turtle shows 3-4.5 fold higher activity with the substrate 4-nitrobenzylchloride than the other 3 species. GST from the herbivorous green sea turtle shows 3 fold higher activity with the substrate ethacrynic acid than the carnivorous olive ridley sea turtle. The results of this study may provide insight into differences in biotransformation potential in the four species of sea turtles and the possible health impacts of contaminant biotransformation by sea turtles.

  18. Análisis del éxito de incubación de la tortuga lora (Lepidochelys olivacea) en función del manejo de los nidos. Península de Osa, Costa Rica

    OpenAIRE

    Malmierca Pérez, Atenea

    2018-01-01

    En este trabajo de final de grado se expone un análisis del éxito de incubación (éxito de eclosión y éxito de emergencia) de la tortuga lora (Lepidochelys olivacea) en las playas Carate y La Leona (Península de Osa, Costa Rica), según los diferentes métodos de manejo de nidos realizados (nidos in situ, nidos reubicados en playa y nidos reubicados en el vivero). El objetivo principal de este trabajo es ver si tanto el manejo de los nidos, como la temperatura de la arena y el recubrimiento h...

  19. Anidación y manejo de la tortuga golfina (Lepidochelys olivacea en la playa La Cuevita, Bahía Solano, Chocó, Colombia

    Directory of Open Access Journals (Sweden)

    Hinestroza, Lina María

    2001-02-01

    Full Text Available Durante la estación de anidación de 1999, documentamos algunos aspectos del comportamiento de anidación de la colonia de Lepidochelys olivacea que desova en la playa La Cuevita en el Pacífico colombiano. Adicionalmente, evaluamos los resultados del programa de maneje por transferencia y protección de nidos para esta estación reproductiva y lo comparamos con años anteriores. Todos los nidos depositados en esta playa que no logran ser transferidos al corral de protección. son depredados por humanos, al igual que una buena proporción de las hembras anidantes. Trasladamos 365 nidos (30197 huevos, de los 377 desoves registrados. El promedio del LCC de las hembras fue de 66 cm (SD= 2,47 y el promedio del número de huevos por nido fue de 102 (SD= 23,04. A diferencia de la estación de 1998, en la presente estación se presentó un pico de anidación evidente y la preferencia de anidación fue en la Lona media de la playa, seguida por la zona de lavado. El éxito de eclosión estimado con base en 304 de los 365 nidos transferidos fue de 71.4% y el éxito reproductivo de 71.8%. Las causas principales de mortalidad dentro del tortugario fueron: escaso o noto desarrollo embrionario. infestación de larvas de moscas en toda o parte de la nidada. asfixia de los neonatos por compactación de la arena. y picaduras por parte de hormigas. El intervalo de temperaturas de incubación estuvo entre los 28,9°C y los 29,4°C, con un promedio de 29.1°C, presentando 51 días de incubación. La evaluación de las proporciones sexuales neonatales de los nidos transferidos fue de 6: 1 en favor de los machos. Nuestros resultados indican que playa La Cuevita es un importante sitio de anidación de Lepidochelys olivacea en Sudamérica. Sin embargo, se deben seguir evaluando las estrategias de manejo empleadas para permitir la eclosión in situ de nidadas, mediante el control de las tasas de depredación humana, e intentar adelantar estudios para determinar

  20. Expression of aromatase in the embryonic brain of the olive ridley sea turtle (Lepidochelys olivacea), and the effect of bisphenol-A in sexually differentiated embryos.

    Science.gov (United States)

    Gómez-Picos, Patsy; Sifuentes-Romero, Itzel; Merchant-Larios, Horacio; Hernández-Cornejo, Rubí; Díaz-Hernández, Verónica; García-Gasca, Alejandra

    2014-01-01

    Brain aromatase participates in several biological processes, such as regulation of the reproductive-endocrine axis, memory, stress, sexual differentiation of the nervous system, male sexual behavior, and brain repair. Here we report the isolation and expression of brain aromatase in olive ridley sea turtle (Lepidochelys olivacea) embryos incubated at male- and female-promoting temperatures (MPT and FPT, respectively), at the thermosensitive period (TSP) and the sex-differentiated period. Also, aromatase expression was assessed in differentiated embryos exposed to bisphenol-A (BPA) during the TSP. BPA is a monomer of polycarbonate plastics and is considered an endocrine-disrupting compound. Normal aromatase expression was measured in both forebrain and hindbrain, showing higher expression levels in the forebrain of differentiated embryos at both incubation temperatures. Although no significant differences were detected in the hindbrain, expression was slightly higher at MPT. BPA did not affect aromatase expression neither in forebrains or hindbrains from embryos incubated at MPT, whereas at FPT an inverted U-shape curve was observed in forebrains with significant differences at lower concentrations, whereas in hindbrains a non-significant increment was observed at higher concentrations. Our data indicate that both incubation temperature and developmental stage are critical factors affecting aromatase expression in the forebrain. Because of the timing and location of aromatase expression in the brain, we suggest that brain aromatase may participate in the imprinting of sexual trends related to reproduction and sexual behavior at the onset of sex differentiation, and BPA exposure may impair aromatase function in the female forebrain.

  1. p-Nitrophenyl Acetate Esterase Activity and Cortisol as Biomarkers of Metal Pollution in Blood of Olive Ridley Turtles (Lepidochelys olivacea).

    Science.gov (United States)

    Cortés-Gómez, Adriana A; Tvarijonaviciute, Asta; Teles, Mariana; Cuenca, Rafaela; Fuentes-Mascorro, Gisela; Romero, Diego

    2017-10-17

    This study was designed to determine the concentrations of p-nitrophenyl acetate esterase activity (EA) and cortisol in serum of marine Olive Ridley turtles (Lepidochelys olivacea) from a Mexican Pacific population ("La Escobilla" beach) and to evaluate the possible relationship of inorganic elements with these biomarkers. EA, cortisol, and selected chemical elements (Cd, Pb, Ti, Sr, Se, Al, As, and Zn) were measured in the blood of 44 sea turtles from the Eastern Pacific (Southeast Mexico). Serum EA ranged from 0.4 to 3.9 UI mL -1 , and cortisol concentrations ranged from 0.07 to 2.5 μL dL -1 . A strong negative correlation between EA and cortisol was observed (r = - 0.59, p < 0.01), and significant correlations also were found between EA and important metals, such as Cd (r = - 0.31, p < 0.05) and Pb (r = - 0.27, p < 0.05), and elements of growing concern like Ti (r = - 0.37, p < 0.01) or Al (r = - 0.34, p < 0.05) and between cortisol and Sr (r = 0.29, p < 0.05), Se (r = - 0.38, p < 0.01), and As (r = - 0.26, p < 0.05). These results suggest that turtles chronically exposed to different inorganic elements (such as Pb and Cd), driving to a highly consume of esterase and to a prolonged cortisol elevation. The obtained results indicate the usefulness of these biomarkers in the assessment of inorganic elements pollution in this species.

  2. Basal and stress-induced corticosterone levels in olive ridley sea turtles (Lepidochelys olivacea) in relation to their mass nesting behavior.

    Science.gov (United States)

    Valverde, R A; Owens, D W; MacKenzie, D S; Amoss, M S

    1999-11-01

    Adrenocortical responsiveness to turning stress was examined in wild, reproductively-active olive ridley sea turtles (Lepidochelys olivacea) in relation to their mass nesting (arribada) behavior. We hypothesized that the high sensitivity threshold (HST) observed in ovipositing sea turtles is associated with a diminished sensitivity of the hypothalamo-pituitary-adrenal (HPA) axis to stressful stimuli in arribada females. We tested this hypothesis by determining whether arribada females exhibited an increased activation threshold of the HPA axis to an imposed stressor (turning stress). Mean basal corticosterone (B) and glucose levels were below 1.0 ng/ml and 60 mg/dl, respectively. Basal B remained unchanged throughout a 24-hr period in basking females. Most animals responded to turning stress with elevated mean B levels (up to 6.5 ng/ml after 6 hr) and no increase in circulating glucose. Nearly 50% of females (and none of the males) were refractory to the stimulation. Males exhibited the most rapid response, with B levels significantly elevated by 20 min over basal levels. Among females, arribada and solitary nesters exhibited a slower rate of response than basking, non-nesting animals. These results demonstrate that olive ridleys exhibit stress-induced changes in circulating B which are slower than those observed in most reptilian and in mammalian, avian, and piscine species. Furthermore, the presence of refractory females and the relatively slower increase in B in arribada and solitary nesters indicate a hyporesponsiveness of the HPA axis to turning stress in nesting olive ridleys. The hyporesponsiveness may be part of a mechanism to facilitate arribada nesting. J. Exp. Zool. 284:652-662, 1999. Copyright 1999 Wiley-Liss, Inc.

  3. [Chemical composition of eggs of the Olive Ridley Lepidochelys olivacea (Testudines: Cheloniidae) and it's potential as a food source].

    Science.gov (United States)

    Castro-González, María Isabel; Pérez-Gil Romo, Fernando

    2011-12-01

    The Olive Ridley is a worldwide distributed species with high nesting production per season, and in La Escobilla Oaxaca, México, there is a 70% of non-hatched eggs that are lost. In order to evaluate their potential use as a source for human and animal food products, their chemical composition was analyzed. Lyophilized egg samples from 25 turtles were obtained and were analyzed following the analytical methods for fatty acids, protein, fat, ash, moisture, amino acids, vitamins, cholesterol and microbiological agents. The analytical composition obtained was (g/100g): moisture (4.7), ash (3.8), protein (53.7), and fat (47.4). The essential amino acid (g aa/100g protein) content was: Ile (4.4), Lys (6.6), Leu (7.4), Met+Cys (8.8), Phe+Tyr (10.8). The vitamin content was: retinol (340 microg/100g), cholecalciferol (5.91 microg/100g) and 8.6 mg/100 tocopherol, 0.3 mg/100g thiamine and 1.1 mg/100g riboflavin. The total lipid content (TL), fatty acids (FA), and cholesterol (Chol) were divided into three groups based on the weight of the turtle: (TL) (44.3-48.7-49.1g/100g) and (Chol) (518.4-522.5 mg/100g-728.7). A total of 17 Saturated FA (SFA), 8 Monounsaturated FA (MUFA) and 11 Polyunsaturated FA (PUFA) were identified. The most abundant SFA (mg/100g) were: C14:0 (445-772), C16:0 (485-1263); MUFA: C16:1 (456-716), C18:1n-9c (904-1754), and PUFA: C20:4n-6 (105-217); two n-3 fatty acids were identified EPA (48-103) and DHA (97-189).There were significant differences (Fisher, p olivacea eggs are an option for its inclusion in the development of food products as they can be used as a high quality biological protein and n-3 fatty acid source for fortification and enrichment.

  4. Composición química del huevo de Tortuga Golfina Lepidochelys olivacea (Testudines: Cheloniidae y su potencial como recurso alimenticio

    Directory of Open Access Journals (Sweden)

    María Isabel Castro-González

    2011-12-01

    Full Text Available Por su potencial como fuente alimenticia, se analizó la composición química de huevo de Lepidochelys olivácea en La Escobilla, Oaxaca, México. El Instituto de Ciencias del Mar y Limnología de la Universidad Nacional Autónoma de México proporcionó 250 muestras de huevo liofilizado de 25 tortugas, que se analizaron siguiendo métodos oficiales para humedad, cenizas, proteína, grasa, lípidos totales(LT y análisis microbiológicos; además de ácidos grasos(AG por cromatografía de gases, aminoácidos(AA, vitaminas y colesterol(col por HPLC. Los resultados fueron los siguientes: (g/100g humedad(4.7, cenizas(3.8, proteína(53.7 y grasa(47.4. AA esenciales (g aa/100g Proteína: Ile (4.4, Lys(6.6, Leu(7.4, Met+Cys (8.8, Phe+Tyr (10.8; retinol (340μg/100g, colecalciferol (5.9 μg/100g, tocoferol (8.6, tiamina (0.3 y riboflavina (1.1 (mg/100g. Y los de (LT, (AG y (Col se concentraron en tres grupos por peso de tortuga: (LT (44.3-48.7-49.1g/100g, (Col (518.4-522.5-728.7 mg/100g. Entonces se identificaron 17 AGSaturados, 8 AGMonoinsaturados y 11 AGPoliinsaturados. Los AGS más abundantes (mg/100g: C16:0 (485-1263, AGM: C16:1 (456-716, C18:1n-9c (904- 1754 y AGP: C20:4n-6 (105-217, EPA (48-103 y HA (97-189. También, existió diferencia significativa (Fisher, p<0.05 para (Col, AG totales, AGS, AGM, AGP y AG n-3 (EPA+DHA. No se detectó presencia de agentes microbiológicos. El huevo liofilizado de L. olivacea es una opción para el desarrollo de productos alimenticios por su proteína de alto valor biológico y ácidos grasos n-3.

  5. Composición química del huevo de Tortuga Golfina Lepidochelys olivacea (Testudines: Cheloniidae y su potencial como recurso alimenticio

    Directory of Open Access Journals (Sweden)

    María Isabel Castro-González

    2011-12-01

    Full Text Available Por su potencial como fuente alimenticia, se analizó la composición química de huevo de Lepidochelys olivácea en La Escobilla, Oaxaca, México. El Instituto de Ciencias del Mar y Limnología de la Universidad Nacional Autónoma de México proporcionó 250 muestras de huevo liofilizado de 25 tortugas, que se analizaron siguiendo métodos oficiales para humedad, cenizas, proteína, grasa, lípidos totales(LT y análisis microbiológicos; además de ácidos grasos(AG por cromatografía de gases, aminoácidos(AA, vitaminas y colesterol(col por HPLC. Los resultados fueron los siguientes: (g/100g humedad(4.7, cenizas(3.8, proteína(53.7 y grasa(47.4. AA esenciales (g aa/100g Proteína: Ile (4.4, Lys(6.6, Leu(7.4, Met+Cys (8.8, Phe+Tyr (10.8; retinol (340μg/100g, colecalciferol (5.9 μg/100g, tocoferol (8.6, tiamina (0.3 y riboflavina (1.1 (mg/100g. Y los de (LT, (AG y (Col se concentraron en tres grupos por peso de tortuga: (LT (44.3-48.7-49.1g/100g, (Col (518.4-522.5-728.7 mg/100g. Entonces se identificaron 17 AGSaturados, 8 AGMonoinsaturados y 11 AGPoliinsaturados. Los AGS más abundantes (mg/100g: C16:0 (485-1263, AGM: C16:1 (456-716, C18:1n-9c (904- 1754 y AGP: C20:4n-6 (105-217, EPA (48-103 y HA (97-189. También, existió diferencia significativa (Fisher, pChemical composition of eggs of the Olive Ridley Lepidochelys olivacea (Testudines: Cheloniidae and it’s potential as a food source. The Olive Ridley is a worldwide distributed species with high nesting production per season, and in La Escobilla Oaxaca, México, there is a 70% of non-hatched eggs that are lost. In order to evaluate their potential use as a source for human and animal food products, their chemical composition was analyzed. Lyophilized egg samples from 25 turtles were obtained and were analyzed following the analytical methods for fatty acids, protein, fat, ash, moisture, amino acids, vitamins, cholesterol and microbiological agents. The analytical composition obtained

  6. Identification and evaluation of semiochemicals for the biological control of the beetle Omorgus suberosus (F.) (Coleoptera: Trogidae), a facultative predator of eggs of the sea turtle Lepidochelys olivacea (Eschscholtz).

    Science.gov (United States)

    Cortez, Vieyle; Verdú, José R; Ortiz, Antonio J; Halffter, Gonzalo

    2017-01-01

    The beetle Omorgus suberosus (F.) is a facultative predator of eggs of the olive ridley turtle Lepidochelys olivacea (Eschscholtz). Laboratory and field investigations were conducted in order to characterize volatile attractants of O. suberosus and to explore the potential for application of these volatiles in a selective mass trapping method. Headspace sorptive extraction (HSSE) coupled to thermo-desorption gas chromatography-mass spectrometry (TD-GC-MS) analysis of the volatile constituents from beetles or turtle nests revealed 24 potential compounds. However, electroantennographic (EAG) measurements revealed antennal sensitivity only to indole, linoleic acid, trimethylamine, dimethyl sulphide, dimethyl disulphide and ammonia. Behavioural tests showed that these compounds are highly attractive to O. suberosus. Field trapping experiments revealed that indole and ammonia were more attractive than the other volatile compounds and showed similar attractiveness to that produced by conventional baits (chicken feathers). The use of a combined bait of indole and NH3 would therefore be the most effective trap design. The data presented are the first to demonstrate effective massive capture of O. suberosus using an attractant-based trapping method. These findings have potential for the development of an efficient mass trapping method for control of this beetle as part of efforts towards conservation of L. olivacea at La Escobilla in Oaxaca, Mexico.

  7. Identification and evaluation of semiochemicals for the biological control of the beetle Omorgus suberosus (F. (Coleoptera: Trogidae, a facultative predator of eggs of the sea turtle Lepidochelys olivacea (Eschscholtz.

    Directory of Open Access Journals (Sweden)

    Vieyle Cortez

    Full Text Available The beetle Omorgus suberosus (F. is a facultative predator of eggs of the olive ridley turtle Lepidochelys olivacea (Eschscholtz. Laboratory and field investigations were conducted in order to characterize volatile attractants of O. suberosus and to explore the potential for application of these volatiles in a selective mass trapping method. Headspace sorptive extraction (HSSE coupled to thermo-desorption gas chromatography-mass spectrometry (TD-GC-MS analysis of the volatile constituents from beetles or turtle nests revealed 24 potential compounds. However, electroantennographic (EAG measurements revealed antennal sensitivity only to indole, linoleic acid, trimethylamine, dimethyl sulphide, dimethyl disulphide and ammonia. Behavioural tests showed that these compounds are highly attractive to O. suberosus. Field trapping experiments revealed that indole and ammonia were more attractive than the other volatile compounds and showed similar attractiveness to that produced by conventional baits (chicken feathers. The use of a combined bait of indole and NH3 would therefore be the most effective trap design. The data presented are the first to demonstrate effective massive capture of O. suberosus using an attractant-based trapping method. These findings have potential for the development of an efficient mass trapping method for control of this beetle as part of efforts towards conservation of L. olivacea at La Escobilla in Oaxaca, Mexico.

  8. Physiological and Behavioral Adjustments Relative to Catecholamine Levels During Nesting in Olive Ridley (Lepidochelys Olivacea and Hawksbill (Eretmochelys Imbricata Sea Turtles in Masirah Island, Oman.

    Directory of Open Access Journals (Sweden)

    A.Y.A AlKindi

    2003-06-01

    Full Text Available Plasma adrenaline (ADR and noradrenaline (NA levels were measured for the first time in natural populations of hawksbill (Eretmochelys imbricata and olive ridley (Lipedochelys olivacea in Masirah Island, Arabian Sea; one of the few protected nesting grounds remaining in the world for these two endangered species. Plasma ADR and NA levels were assessed in individuals after they oviposited eggs and completed nesting exercises, and in individuals which were still searching for suitable nesting sites. Blood samples were taken from the cervical sinuses from two groups (oviposited and non-oviposited, which spent at least 1.5 h on the nesting grounds. The duration of the nesting period varied between 1.5 and 2.0 h for both species. There was no significant difference between oviposited and non-oviposited turtles in both species. As the turtles move onto the nesting grounds, their heavy weight compresses the thoracic region making terrestrial breathing laborious and difficult. During phases of nesting, the turtles undergo brief bursts of strenuous and exhaustive exercise which usually lasts less than one minute followed by a brief recovery period which is less than the exercise phase. Reptiles in general, particularly turtles, are intermittent breathers and after bursts of exercise, they appear to develop hypoxia, hypercapnia and acidemia, which are characteristic of anaerobic metabolism. The data reveals that catecholamine levels remain stable in both species during phases of nesting and may play an important role in combating stress as well as mobilizing energy reserves. The high plasma lactate and CO2 levels in olive and hawksbill turtles may signify anaerobic metabolism during exercise. Glucose levels remain unchanged throughout nesting in both species. There was no significant difference in the lactate and glucose values in the two species. The physiological and the behavioral adjustments in this study showed remarkable similarities in the two

  9. Contribución al conocimiento de los hábitos alimenticios de Lepidochelys olivacea y Chelonia mydas agassizi (Reptilia, Cheloniidae en el Pacífico Mexicano

    Directory of Open Access Journals (Sweden)

    Gustavo Casas-Andreu

    1980-12-01

    Full Text Available The results of a study on the feeding habits of L. olivacea and C. mydas agassizi from the Pacific coast, located at 19ºN and 105ºW, are presented. A preference for feeding on crustacea was observed on L. olivacea, proving to be essentially a carnivorous specie. In the case of C. m. agassizi a certain balance between algae and animal feeding was appreciated, beeing the plants in a greater volume and animals more diversified. Related to animal preying C m. agassizi bucal structure, seems to be adapted toward the retention of animals captured with algae. Apparently there is no competition for food between both species,, given that L. olivacea feeds on organisms from sandy bottoms, while C. m, agassizi feeds on arrecifal or rocky bottoms.

  10. La tortue marine au Cameroun, genre Lepidochelys : nidification ...

    African Journals Online (AJOL)

    Ce document présente les données recueillies sur Lepidochelys olivacea le long des côtes de la réserve de Campo-Ma'an au Cameroun. Les études menées de 1998 à 2005 ont consisté en un recensement des espèces venant pondre sur les plages et une délimitation des périodes de pontes. Des mesures ont été ...

  11. Genotoxic Biomarkers in Erythrocytes of Lepidochelys olivacea (Cheloniidae from Colombia

    Directory of Open Access Journals (Sweden)

    Victor Hugo Quiroz Herrera

    2017-09-01

    Full Text Available This research was conducted in the municipality of Bahia Solano, Colombia, and had as a goal to detect damage erythrocytes circulating with nuclear lesions in fifty-five Olive Ridley adult females using acridine orange immunostain, and correlate its frequencies with some physiological and biometric parameters. We determine a micronucleated erythrocytes (MNE frequency of 0.6 ± 0.6 and nuclear buds (NBE of 2.1 ± 1.9. We not found any relationship between the nuclear lesions with physiological or biometric parameters evaluated (Pearson and Kruskal-Wallis, p<0.05. We define a significative statistical difference (p=0.035 between both nuclear lesions frequencies. This results show nuclear damages in erythrocytes of Olive Ridley sea turtle for the first time in Colombia as an outcome of genotoxic stress. Also contributes key information for future research in the ecotoxicology area for endangered marine species.

  12. Global phylogeography of the ridley sea turtles (Lepidochelys spp.) as inferred from mitochondrial DNA sequences.

    Science.gov (United States)

    Bowen, B W; Clark, A M; Abreu-Grobois, F A; Chaves, A; Reichart, H A; Ferl, R J

    The Kemp's ridley sea turtle (Lepidochelys kempi) is restricted to the warm temperate zone of the North Atlantic Ocean, whereas the olive ridley turtle (L. olivacea) is globally distributed in warm-temperate and tropical seas, including nesting colonies in the North Atlantic that nearly overlap the range of L. kempi. To explain this lopsided distribution, Pritchard (1969) proposed a scenario in which an ancestral taxon was divided into Atlantic and Pacific forms (L. kempi and L. olivacea, respectively) by the Central American land bridge. According to this model, the olive ridley subsequently occupied the Pacific and Indian Oceans and recently colonized the Atlantic Ocean via southern Africa. To assess this biogeographic model, a 470 bp sequence of the mtDNA control region was compared among 89 ridley turtles, including the sole L. kempi nesting population and 7 nesting locations across the range of L. olivacea. These data confirm a fundamental partition between L. olivacea and L. kempi (p = 0.052-0.069), shallow separations within L. olivacea (p = 0.002-0.031), and strong geographic partitioning of mtDNA lineages. The most divergent L. olivacea haplotype is observed in the Indo-West Pacific region, as are the central haplotypes in a parsimony network, implicating this region as the source of the most recent radiation of olive ridley lineage. The most common olive ridley haplotype in Atlantic samples is distinguished from an Indo-West Pacific haplotype by a single nucleotide substitution, and East Pacific samples are distinguished from the same haplotype by two nucleotide substitutions. These shallow separations are consistent with the recent invasion of the Atlantic postulated by Pritchard (1969), and indicate that the East Pacific nesting colonies were also recently colonized from the Indo-West Pacific region. Molecular clock estimates place these invasions within the last 300,000 years.

  13. Notes on the zoogeography of the Atlantic sea turtles of the genus Lepidochelys

    Directory of Open Access Journals (Sweden)

    Archie Carr

    2002-06-01

    Full Text Available The sea turtle Lepidochelys kempi has an extensive range in coastal waters of the United States, and in parts of Florida is abundant as a seasonal resident. All known populations are sexually immature, and the breeding area of the species is not known. The present paper suggests the necessity of assuming a distant origin for the North American population, examines fragmentary evidence bearing on the coronary assumption of migratory movement, and somewhat hesitantly proposes the coast of northwestern Africa as a possible site of nesting. Spreading into American waters may occur via the Gulf Stream system. New records extend the range of the genus to northern Mauretania and into the MediterraneanLa tortuga marina Lepidochelys kempi tiene amplia distribución en el litoral de los Estados Unidos, y abunda como visitante en la costa occidental de Florida, si bien en la costa oriental hay un trecho desde Melbourne hasta Miami en que no ha sido registrada. Tampoco ha sido registrada en las Bahamas ni en las Antillas, aunque un ejemplar recogido en Cuba, mencionado por AGUAYO (1 parece ser la especie africana L. olivacea, que se debe considerar como visitante y ocasional de esas islas; también existe por 10 menos un ejemplar registrado en las cercanías de Bermuda, y queda la posibilidad de que la "batalí" de Trinidad sea una u otra especie de Lepidochelys. L. olivacea, que se debe considerar como visitante y ocasional de esas islas; también existe por lo menos un ejemplar registrado en las cercanías de Bermuda, y queda la posibilidad de que la "batalí" de Trinidad sea una u otra especie de Lepidochelys. Todas las poblaciones conocidas en aguas norteamericanas son sexualmente inmaturas, y no se conoce el criadero de la especie. En este trabajo el autor sugiere la necesidad de suponer un punto de origen distante para estas poblaciones; examina los fragmentos disponibles de evidencia que apoyan la suposición corolaria de movimientos migratorios, y

  14. Ontogeny of energetics in leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) sea turtle hatchlings.

    Science.gov (United States)

    Jones, T Todd; Reina, Richard D; Darveau, Charles-A; Lutz, Peter L

    2007-06-01

    Changes in activity related oxygen consumption were measured in leatherback and olive ridley sea turtle hatchlings over their first month after emergence from the nest. Leatherbacks emerged with 75-90 KJ of energy in the residual yolk for growth and activity whereas olive ridleys emerged with 45 KJ. In leatherbacks (n=8), resting mass-specific oxygen consumption rates decreased by 53% over the first post-hatching month (0.34+0.03 mL O(2) h(-1) g(-1) to 0.16+0.01 mL O(2) h(-1) g(-1), respectively), while for ridleys (n=8) the fall was 35% (0.20+0.03 mL O(2) h(-1) g(-1) to 0.13+0.01 mL O(2) h(-1) g(-1), respectively). Olive ridley factorial aerobic scope doubled (1.93+0.30 to 3.97+0.51) over the first month but there was no significant increase in leatherback factorial aerobic scope (1.39+0.21 to 1.60+0.13). Leatherback hatchlings gained on average 20% initial body mass (7.68+1.66 g) over the first week, with 70 to 80% of this increase due to water accumulation. Olive ridleys gained 14% (1.83+0.16 g) in initial mass over the first week of age. We propose that the differences in aerobic scope and energy reserves are related to differences in early life ecological stratagems of these species.

  15. ÁCIDO ACÉTICO EN HUEVO DE TORTUGA (Lepidochelys olivacea

    Directory of Open Access Journals (Sweden)

    M\\u00F3nica Pereira-Zamora

    2010-01-01

    Full Text Available Este estudio se realizó en el Ce ntro Na cional de Cie ncia y Tecnología de Alimentos en el año 2000, con el fin de determinar la reducción de Vibrio mimicus en huevo de tortuga lora utilizando calor o ácido acético. Para ellos se determinó el tiempo de coagulación a diferentes temperaturas o niveles de pH con el fin de seleccionar los que podían utilizarse para la reducción del patógeno sin afectar las cualidades sensoriales del huevo crudo. Los huevos inoculados con Vibrio mimicus con cargas superiores a 6,0 log10UFC/g, fueron tratados con las diferentes alternativas de inmersión en agua caliente o soluciones de ácido acético por un tiempo determinado. Los tratamientos con calor (45, 55 ó 65ºC por 20 minutos lograron reducciones entre 1,4 y > 6,0 log10UFC/g, mientras que la inmersión en ácido acético (pH 3,0; 3,5; 4,0 ó 4;5 por una hora sólo logró reducciones entre 0,2 y 1,5 log10UFC/g causadas probablemente por la neutralización observada del pH en el tiempo.

  16. Density-dependent effects on hatching success of the olive ridley turtle, Lepidochelys olivacea.

    Science.gov (United States)

    Honarvar, Shaya; O'Connor, Michael P; Spotila, James R

    2008-08-01

    Historically, the olive ridley arribada at Playa Nancite, Costa Rica, was one of the largest olive ridley arribadas in the eastern Pacific with 70,000 nesting females in a year. Recently the Nancite arribada drastically declined. We hypothesized that the population decline at Playa Nancite could have been due to low hatching success as a result of the high density of nests on the beach, such that recruitment to the population was insufficient to balance losses. To test this hypothesis, we examined density-dependent effects on hatching success and their underlying mechanisms by experimentally manipulating nest densities in experimental plots on the nesting beach. We set up four nest-density treatments in five experimental blocks. We measured effects of density on hatching success, CO(2) and O(2) concentrations and temperature both within nests and in sand adjacent to nests frequently during incubation. Experimental nest densities affected hatching success with the highest density having the lowest hatching success. Higher nest density led to lower O(2) levels and higher CO(2) levels in the nest with greater changes in the latter part of the incubation. Highest temperatures occurred in high-density areas. Temperatures were lower in sand surrounding the nest than in the nest. Effects of density on temperature, CO(2) and O(2) were confirmed at a naturally high-density nesting beach, Playa La Flor, Nicaragua. Long-term failure in production of hatchlings due to historic high densities may have contributed to the decline of arribadas on Playa Nancite. Thus, density-dependent population control would have operated at the embryonic life stage in this population of olive ridley turtles.

  17. Comparative Study of Plasma Parameters in Olive Ridley (Lepidochelys Olivacea and Hawksbill (Eretmochelys Imbricata During Nesting

    Directory of Open Access Journals (Sweden)

    A.Y.A. Alkindi

    2002-06-01

    Full Text Available The aim of this study is to investigate the role of plasma level parameters during nesting activity and provide data potentially useful to future studies on the dynamics of reproductive and stress hormones in the most endangered sea turtle species in the world. Plasma parameters in the sea turtles, olive ridley (Lipodochelys oliveacea and hawksbill (Eretmochelys imbricata from Masirah Island, Oman, were analyzed relative to nesting stress. To date, no study has been conducted on plasma parameter levels in sea turtles during nesting. Field observations were conducted under ideal temperature conditions. At the time of sampling, there was no significant difference for cloacal, sand, air or water temperature for the two species. Electrolytes (Cl¯, Ca++, K+, Na+ and Mg++, cholesterol, urea, uric acid and osmolarity were measured during nesting. Both species were observed to spend between 1.5 and 2.00 hours on the nesting grounds. Some had successful oviposition and completed all nesting phases, while others with incomplete nesting phases failed to oviposit their  eggs. Under both conditions, the turtles of both species had an exhaustive and stressful nesting exercise. Plasma parameter values, both intra-specifically and inter-specifically, were not significantly different for oviposited and non-oviposited turtles. This may indicate that both species have the same physiological adjustment relative to plasma parameters whether or not the turtles oviposited their eggs.

  18. Microsphaeropsis olivacea keratitis and consecutive endophthalmitis.

    Science.gov (United States)

    Shah, C V; Jones, D B; Holz, E R

    2001-01-01

    To report a case of fungal keratitis with consecutive endophthalmitis caused by Microsphaeropsis olivacea. Case report. A 51-year-old man developed fungal keratitis and consecutive endophthalmitis after sustaining a penetrating injury to the right eye. Cultures of the aqueous humor yielded M. olivacea. Infection resolved after intraocular fungal debridement, intravitreous amphotericin B, and aggressive topical natamycin and oral fluconazole. Persistent, low-grade smoldering corneal and intraocular inflammation required topical corticosteroid therapy. M. olivacea is an exceedingly rare ocular pathogen. The intraocular portion of the infection responded quickly to intravitreal antifungal treatment; however, the course was prolonged by smoldering corneal inflammation. Prompt recognition of intraocular spread and aggressive treatment may be beneficial in fungal infections caused by unusual organisms with uncertain virulence.

  19. Nesting Habitat Suitability for Olive Ridley Turtles (Lepidochelys Olivacea at the Gahirmatha Rookery, Odisha Coast of India

    Directory of Open Access Journals (Sweden)

    Satyaranjan BEHERA

    2013-12-01

    Full Text Available The changes in the beach dynamics at Gahirmatha sea turtle rookery along Odisha coast of India have forced the olive ridley turtles to nests in a non-conducive environment. In the recent past, non-availability of nesting beach due to erosion was hypothesized to be one of the major reasons for non-occurrence of arribada at Gahirmatha. This paper reviews the current status of nesting habitat for olive ridley turtles at Gahirmatha and suggests onshore and offshore developmental activities close to Gahirmatha rookery should be monitored efficiently so that future arribada at this rookery should not be troubled due to habitat destruction.

  20. Perbandingan Laju Pertumbuhan Tukik Penyu Lekang (Lepidochelys olivacea dengan Pemberian Pakan Ikan Tongkol, Udang Rebon Kering dan Pakan Campuran

    Directory of Open Access Journals (Sweden)

    Cornelia Coraima Lazaren

    2017-09-01

    Full Text Available The population of olive ridley has declined in Indonesia, so that efforts are needed to preserve this turtle population through conservation. In conservation of olive ridley, the selection of the precise feed will affect for a good growth. Feed that has high protein content one of them is dried rebon shrimp and tongkol fish. The utilization of feed from dried rebon shrimp and tongkol fish, especially mix feed of these two feeds for olive ridley baby is still very limited information. This research aims to determine the comparison growth rate of olive ridley with a feeding of tongkol fish, dried rebon shrimp and mixed feed also to know the percentage of feed efficiency. The research was conducted for six weeks at the conservation center TCEC Serangan, Bali. The design method used was Completely Randomized Design (CDR with one control and three treatments, each treatment getting five repetitions. ANOVA analysis was used to analyze the mean differences between groups and the calculation of feed efficiency was performed to see the percentage of feed that was most efficient in the body of the hatch. The results showed different feeds gave different growth rates. The high protein on mixed feeds has produced the highest growth rates compared with dried rebon shrimp and tongkol fish feed. Similarly, the percentage efficiency of mixed feed is more efficient compared with dried rebon shrimp and tongkol fish feed.

  1. Isotopic effects of different preservation methods on scales of olive ridley sea turtles (Lepidochelys olivacea) from the Mexican Central Pacific.

    Science.gov (United States)

    Carpena-Catoira, Carla; Ortega-Ortiz, Christian D; Elorriaga-Verplancken, Fernando R

    2016-09-08

    Stable isotope analysis can be used to obtain information on olive ridley sea turtles in the Mexican Central Pacific (MCP). Tissue samples such as scale, muscle, and blood are usually not analyzed immediately and are preserved in different substances such as ethanol, formalin, sodium chloride, the ideal being liquid nitrogen. Due to logistical reasons, that preservation method cannot always be used. The objective of the present study was to evaluate the efficiency of DMSO as a preservation agent for later stable isotope analysis. Forty-eight paired scale samples of olive ridley were collected in MCP waters and preserved in DMSO and liquid nitrogen. We determined their δ 13 C and δ 15 N values using a Carlo Erba 1108 elemental analyzer coupled to a ThermoFinnigan Delta Plus XP isotope ratio mass spectrometer (precision = ±0.2‰ for each stable isotope). The mean isotopic ratios of each preservation method were compared. Significant differences were observed between the isotopic ratios of samples in the two preservatives. Samples preserved in DMSO resulted in more negative isotopic values those in liquid nitrogen, and a correction factor was calculated' The correction factor was -2.1‰ for δ 13 C values and -0.8‰ for δ 15 N values. DMSO is not equivalent to liquid nitrogen for the preservation of olive ridley scales to be used for isotopic analysis. If DMSO has to be used for logistical reasons a replicate sample should also be collected to be able to estimate a correction factor. This article is protected by copyright. All rights reserved.

  2. Temperature regulates SOX9 expression in cultured gonads of Lepidochelys olivacea, a species with temperature sex determination.

    Science.gov (United States)

    Moreno-Mendoza, N; Harley, V R; Merchant-Larios, H

    2001-01-15

    Although sex determination starts in the gonads, this may not be the case for species with temperature sex determination (TSD). Since temperature affects the whole embryo, extragonadal thermosensitive cells may produce factors that induce gonadal sex determination as a secondary event. To establish if gonads of a species with TSD respond directly to temperature, pairs of gonads were cultured, one at female-promoting temperature (FPT) and the contralateral at male-promoting temperature (MPT). Histological and immunohistochemical detection of SOX9 revealed that the response to temperature of isolated gonads was similar to that of the gonads of whole embryos. While gonads cultured at MPT maintained SOX9 expression, it was downregulated in gonads at FPT. Downregulation of SOX9 took longer in gonads cultured at stage 23 than in gonads cultured at stage 24, suggesting that a developmental clock was already established at the onset of culture. To find out if sex commitment occurs in vitro, gonads were switched from FPT to MPT at different days. Results showed that the ovarian pathway was established after 4 days of culture. The present demonstration that gonads have an autonomous temperature detector that regulates SOX9 expression provides a useful starting point from which the molecular pathways underlying TSD can be elucidated. Copyright 2001 Academic Press.

  3. Perbandingan Laju Pertumbuhan Tukik Penyu Lekang (Lepidochelys olivacea) dengan Pemberian Pakan Ikan Tongkol, Udang Rebon Kering dan Pakan Campuran

    OpenAIRE

    Cornelia Coraima Lazaren; I Wayan Gede Astawa Karang; Elok Faiqoh

    2017-01-01

    The population of olive ridley has declined in Indonesia, so that efforts are needed to preserve this turtle population through conservation. In conservation of olive ridley, the selection of the precise feed will affect for a good growth. Feed that has high protein content one of them is dried rebon shrimp and tongkol fish. The utilization of feed from dried rebon shrimp and tongkol fish, especially mix feed of these two feeds for olive ridley baby is still very limited information. This res...

  4. SOBREVIVENCIA DE Vibrio mimicus EN LA CLARA Y EN LA YEMA DEL HUEVO DE TORTUGA LORA (Lepidochelys olivacea)

    OpenAIRE

    M\\u00F3nica Pereira-Zamora; Eric Wong-Gonz\\u00E1lez

    2008-01-01

    En el año 2000, en el Centro Nacional de Ciencia y Tecnología de Alimentos de la Universidad de Costa Rica, se estudió la sobrevivencia de Vibrio mimicus en la clara y yema del huevo de tortuga lora. Se inocularon muestras de clara o yema con el vibrio (aproximadamente 2,5 x 104 UFC/g) y se determinó la carga inicial y final al cabo de 18 horas de incubación a 25°C. De forma análoga se trabajó una muestra control en agua peptonada alcalina(APA) como medio óptimimo de crecimiento para el vibri...

  5. PEMELIHARAAN LARVA KEPITING BAKAU, Scylla olivacea DENGAN PENAMBAHAN BIOFLOK

    Directory of Open Access Journals (Sweden)

    Gunarto Gunarto

    2014-06-01

    Full Text Available Abstrak lengkap dapat dilihat pada Full PDF   Tujuan penelitian ini adalah untuk mengetahui efek penambahan bioflok pada pemeliharaan larva kepiting bakau Scylla olivacea terutaman pada sintasan dan perkembangan larva hingga mencapai stadia krablet.

  6. Development and fine structure of sclerotia and spores of the actinomycete Chainia olivacea.

    Science.gov (United States)

    Sharples, G P; Williams, S T

    1976-01-01

    Sclerotia and spores of Chainia olivacea were studied by transmission and scanning electron microscopy. Sclerotia formed by repeated branching of several hyphea. Branch tips were delimited by septa and increased in size, becoming filled with lipid-like inclusions. In mautre sclerotia, empty cells and intra-hyphal growth were observed. An electron-dense fibrillar material was deposited between hyphae and on the sclerotium surface. The similarities between these and the sclerotia of certain fungi are discussed. Spores were formed in a manner similar to that in Streptomyces species. Large inter-sporal pads were formed during ingrowth of the septa delimiting the spores.

  7. Microsphaeropsis olivacea as an etiological agent of human skin infection.

    Science.gov (United States)

    Guarro, J; Mayayo, E; Tapiol, J; Aguilar, C; Cano, J

    1999-04-01

    Microsphaeropsis olivacea is reported as the agent of a case of human skin infection in an otherwise healthy woman. This fungus has not been reported previously as causing disease in humans. It was identified on the basis of its production of pycnidia and conidial structures typical of the Coelomycetes, and by its light brown, ellipsoid to cylindrical and thick walled conidia. The in vitro inhibitory activity of amphotericin B, fluconazole, flucytosine, itraconazole, ketoconazole and miconazole was determined.

  8. 75 FR 81201 - 2011 Annual Determination for Sea Turtle Observer Requirement

    Science.gov (United States)

    2010-12-27

    ... endangered. Loggerhead (Caretta caretta), green (Chelonia mydas), and olive ridley (Lepidochelys olivacea.... waters are listed as either endangered or threatened under the ESA. Kemp's ridley (Lepidochelys kempii...

  9. 77 FR 36571 - Endangered Species; Receipt of Applications for Permit

    Science.gov (United States)

    2012-06-19

    ... turtle (Lepidochelys olivacea) for the purpose of scientific research. Samples are collected from live or... (Lepidochelys kempii), hawksbill sea turtle (Eretmochelys imbricata), leatherback sea turtle (Dermochelys...

  10. 78 FR 24432 - Receipt of Applications for Endangered Species Permits

    Science.gov (United States)

    2013-04-25

    ... (Lepidochelys kempii), hawksbill (Eretmochelys imbricata), leatherback (Dermochelys coriacea), green (Chelonia mydas), loggerhead (Caretta caretta), and olive ridley (Lepidochelys olivacea) sea turtles for...

  11. 77 FR 75999 - 2013 Annual Determination for Sea Turtle Observer Requirement

    Science.gov (United States)

    2012-12-26

    ... (Lepidochelys olivacea) sea turtles are listed as threatened, except for breeding colony populations of green... (Lepidochelys kempii), loggerhead (Caretta caretta; North Pacific distinct population segment), leatherback...

  12. 50 CFR 224.101 - Enumeration of endangered marine and anadromous species.

    Science.gov (United States)

    2010-10-01

    ... imbricata); Kemp's ridley turtle (Lepidochelys kempii); Leatherback turtle (Dermochelys coriacea); Olive ridley turtle (Lepidochelys olivacea) breeding colony population on the Pacific coast of Mexico. Note to...

  13. 75 FR 32811 - Emergency Issuance of Endangered Species Permits

    Science.gov (United States)

    2010-06-09

    ... olive ridley (Lepidochelys olivacea) sea turtles for veterinary treatment or euthanasia under certain... receive and retain, for greater than 45 days, Kemp's Ridley (Lepidochelys kempii), hawksbill (Eretmochelys...

  14. 76 FR 37327 - Endangered Species; File No. 16253

    Science.gov (United States)

    2011-06-27

    ... form for a permit to take green (Chelonia mydas), Kemp's ridley (Lepidochelys kempii), hawksbill (Eretmochelys imbricata), leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), and...

  15. 78 FR 77428 - 2014 Annual Determination for Sea Turtle Observer Requirement

    Science.gov (United States)

    2013-12-23

    ... population segment), green (Chelonia mydas), and olive ridley (Lepidochelys olivacea) sea turtles are listed... or threatened under the ESA. Kemp's ridley (Lepidochelys kempii), loggerhead (Caretta caretta; North...

  16. A new variety of Chainia olivacea from marine sediment off Gulf of Mannar.

    Science.gov (United States)

    Ellaiah, P; Kalyan, D; Rao, V S; Rao, B V

    1997-01-01

    A new variety of Chainia olivacea was isolated from marine sediment off Gulf of Mannar. The morphological, cultural, physiological and biochemical characters were studied, compared to known species and identified as a new variety of Chainia olivacea. Antibiotic activity of the strain was tested against both Gram positive and Gram negative bacteria as well as fungi and yeasts. Sodium chloride tolerance was also tested.

  17. Ultrastructure of the mature spermatozoon of the bivalve Estellarca olivacea (Mollusca: Bivalvia: Arcidae) and its phylogenetic implications.

    Science.gov (United States)

    Zhu, Jun-Quan; Yang, Wan-Xi

    2009-03-01

    Ultrastructure of mature spermatozoa of Estellarca olivacea was studied by transmission electron microscopy and its phylogenetic implications are discussed for the first time in this paper. The mature spermatozoon is composed of a head which contains a cone-shaped acrosome, a round nucleus and a tail region. The subacrosomal space is less electron dense which contains a homogeneous material. No axial rod and a basal plate were observed in subacrosomal space. No anterior invagination exists in the nucleus, but an inverted shallow V-shaped posterior invagination is visible. Nuclear lacunae could be seen clearly although the nucleus is highly condensed. Within the mid-piece of the spermatozoon there exist five spherical mitochondria while the long whip-like end portion is composed of an axoneme with the typical 9+2 structure. The spermatozoon of Estellarca olivacea is a product of the evolution of the reproductive system of the family Arcidae. Whether the particular acrosome, subacrosomal space, or the highly condensed nucleus might be adaptations of high fertilization rate in the particular environment of this species is discussed.

  18. Parasites of the Great Plains narrowmouth toad (Gastrophryne olivacea) from northern Texas.

    Science.gov (United States)

    McAllister, C T; Upton, S J

    1987-10-01

    Forty-nine adult and 14 immature Great Plains narrowmouth toads (Gastrophryne olivacea) from Johnson and Somervell Counties of northcentral Texas were examined for parasites. Sixty-four percent of the toads were infected with one or more species of parasites. New host records are reported for an isosporan similar to Isospora neos, and for Cylindrotaenia americana. The most common parasite in G. olivacea was the nematode, Cosmocercoides dukae. Prevalence was high among the adult G. olivacea (82%); however, none of the immature toads were infected.

  19. Ascoma development and phylogeny of an apothecioid dothideomycete, Catinella olivacea.

    Science.gov (United States)

    Greif, Matthew D; Gibas, Connie Fe C; Tsuneda, Akihiko; Currah, Randolph S

    2007-11-01

    Catinella olivacea is a discomycetous fungus often found fruiting within cavities in rotting logs. Because this habitat would lack the air currents upon which discomycete species normally rely for the dispersal of their forcibly ejected ascospores, we suspected an alternative disseminative strategy might be employed by this species. An examination of the development of the discomycetous ascomata in pure culture, on wood blocks, and on agar showed that the epithecium was gelatinous at maturity and entrapped released ascospores in a slimy mass. We interpreted this as an adaptation for ascospore disperal by arthropods. Developmental data also showed that C. olivacea was unusual among other discomycetes in the Helotiales (Leotiomycetes). For example, the ascoma developed from a stromatic mass of meristematically dividing cells and involved the formation of a uniloculate cavity within a structure better considered an ascostroma than an incipient apothecium. Furthermore, the ascus had a prominent ocular chamber and released its ascospores through a broad, bivalvate slit. These features, along with phylogenetic analyses of large subunit and small subunit rDNA, indicated that this unusual apothecial fungus is, surprisingly, more closely affiliated with the Dothideomycetes than the Leotiomycetes.

  20. Final Environmental Impact Statement for the Kauai Acoustic Thermometry of Ocean Climate Project and Its Associated Marine Mammal Research Program: Vol 1

    Science.gov (United States)

    1995-05-01

    Eretmochelys imbricata), and olive ridley ( Lepidochelys olivacea ). Hawksbills and leatherbacks are listed at the federal and state levels as endangered (DLNR...schauinslandi green sea turtle Chelonia mydas leatherback sea turtle Dermochelys coriacea olive ridley sea turtle Lepidochelys olivacea hawksbill sea...Dermochelys coriacea), and olive ridley sea turtle ( Lepidochelys olivacea ); and the following threatened species: loggerhead sea turtle (Caretta caretta

  1. Mobile Launch Platform (MLP) Environmental Assessment

    Science.gov (United States)

    2004-06-28

    Lepidochelys olivacea ) (see Exhibit 3-14). Exhibit 3-14. Federally Listed Threatened or Endangered Species within the USAKA Coastal Area Common...sea turtle Dermochelys coriacea Endangered Loggerhead sea turtle Caretta caretta Threatened Olive ridley sea turtle Lepidochelys olivacea Threatened...turtle Dermochelys coriacea Endangered Hawksbill sea turtle Eretmochelys imbricata Endangered Olive ridley sea turtle Lepidochelys olivacea Threatened

  2. Metabolites from Microsphaeropsis olivacea, an endophytic fungus of Pilgerodendron uviferum.

    Science.gov (United States)

    Hormazabal, Emilio; Schmeda-Hirschmann, Guillermo; Astudillo, Luis; Rodríguez, Jaime; Theoduloz, Cristina

    2005-01-01

    Seven compounds belonging to different structural skeletons were isolated from Microsphaeropsis olivacea grown in liquid and solid media. The enalin derivative 7-hydroxy-2,4-dimethyl-3(2H)-benzofuranone is reported for the first time, while additional spectroscopic information is provided for the acetates of botrallin and ulocladol. The activity of the isolated compounds was assessed towards the enzyme acetylcholinesterase (AChE) and their cytotoxicity against human lung fibroblasts. Graphislactone A and botrallin presented a moderate activity towards AChE, with IC50 of 8.1 and 6.1 microg/ml (27 and 19 microM, respectively). Under the same experimental conditions, the IC50 of the standard inhibitor galanthamine was 3 microg/ml. The cytotoxicity of both compounds was > 1000 and 330 microM, respectively. None of the compounds was promising as antibacterial or antifungic against phytopathogenic fungi and bacteria. Botrallin and graphislactone A were detected in the liquid potato-dextrose and yeast extract/malt extract/dextrose as well as on a solid substrate (rice). Butyrolactone I was obtained from the fungus growing on solid medium.

  3. Characterization of the circulating hemocytes in mud crab (Scylla olivacea) revealed phenoloxidase activity.

    Science.gov (United States)

    Mangkalanan, Seksan; Sanguanrat, Piyachat; Utairangsri, Tanatchaporn; Sritunyalucksana, Kallaya; Krittanai, Chartchai

    2014-05-01

    This study focused on an isolation and characterization of the circulating hemocytes in mud crab, Scylla olivacea. Isolation of specific cell types of hemocytes from crab hemolymph was accomplished by using 60% Percoll density gradient centrifugation. Four separated bands of the hemocytes were successfully obtained. Characterization of these isolated hemocytes by light microscope using trypan blue-rose bengal staining, rose bengal-hematoxilin staining, and phase contrast revealed four distinct types of hemocyte cells. Using their specific morphology and granularity, they were identified as hyaline cell (HC), small granular cell (SGC), large granular cell (LGC) and mixed granular cell (MGC). Transmission electron microscopy (TEM) revealed more details on specific cell size, size of cytoplasmic granule, and nuclear to cytoplasmic ratio, and confirmed the classification. Relative abundance of these cells types in the hemolymph of an adult crab were 15.50±8.22% for HC, 55.50±7.15% for SGC, 13.50±5.28% for LGC, and 15.50±3.50% for MGC. Proteomic analysis of protein expression for each specific cell types by two-dimensional electrophoresis identified two highly abundant proteins, prophenoloxidase (ProPO) and peroxinectin in LGC. Determination of phenoloxidase (PO) activity in each isolated cell types using in vitro and in situ chemical assays confirmed the presence of PO activity only in LGC. Based on an increased PO activity of crab hemolymph during the course of White Spot Syndrome Virus (WSSV) infection, these results suggest that prophenoloxidase pathway was employed for host defense mechanism against WSSV and it may link to the role of large granular hemocyte. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Comparative genomics of Coniophora olivacea reveals different patterns of genome expansion in Boletales.

    Science.gov (United States)

    Castanera, Raúl; Pérez, Gúmer; López-Varas, Leticia; Amselem, Joëlle; LaButti, Kurt; Singan, Vasanth; Lipzen, Anna; Haridas, Sajeet; Barry, Kerrie; Grigoriev, Igor V; Pisabarro, Antonio G; Ramírez, Lucía

    2017-11-16

    Coniophora olivacea is a basidiomycete fungus belonging to the order Boletales that produces brown-rot decay on dead wood of conifers. The Boletales order comprises a diverse group of species including saprotrophs and ectomycorrhizal fungi that show important differences in genome size. In this study we report the 39.07-megabase (Mb) draft genome assembly and annotation of C. olivacea. A total of 14,928 genes were annotated, including 470 putatively secreted proteins enriched in functions involved in lignocellulose degradation. Using similarity clustering and protein structure prediction we identified a new family of 10 putative lytic polysaccharide monooxygenase genes. This family is conserved in basidiomycota and lacks of previous functional annotation. Further analyses showed that C. olivacea has a low repetitive genome, with 2.91% of repeats and a restrained content of transposable elements (TEs). The annotation of TEs in four related Boletales yielded important differences in repeat content, ranging from 3.94 to 41.17% of the genome size. The distribution of insertion ages of LTR-retrotransposons showed that differential expansions of these repetitive elements have shaped the genome architecture of Boletales over the last 60 million years. Coniophora olivacea has a small, compact genome that shows macrosynteny with Coniophora puteana. The functional annotation revealed the enzymatic signature of a canonical brown-rot. The annotation and comparative genomics of transposable elements uncovered their particular contraction in the Coniophora genera, highlighting their role in the differential genome expansions found in Boletales species.

  5. Multilocus sequencing reveals multiple geographically structured lineages of Coniophora arida and C. olivacea (Boletales) in North America.

    Science.gov (United States)

    Kauserud, Håvard; Shalchian-Tabrizi, Kamran; Decock, Cony

    2007-01-01

    Coniophora arida and C. olivacea (Coniophoraceae, Boletales) are widespread wood-decay fungi in temperate and boreal regions, occurring both in buildings and natural environments. Genetic variation and geographic structure among isolates of C. arida and C. olivaceae were investigated in this study, with an emphasis on North America. Multilocus sequencing of three DNA regions revealed three main lineages in C. arida and six in C. olivacea, some of which might represent cryptic species. Most of the lineages are present in North America, mainly in allopatry, suggesting recent or ongoing geographic speciation. One of the C. arida isolates included a high number of heterozygous sites and might represent a hybrid between two cryptic C. arida lineages. The data indicate out-crossing reproductive modes in both C. arida and C. olivacea. Together with other recent investigations of Coniophora species our data suggest that the genus comprises a significant number of cryptic species and is much more diverse than previously deduced from morphological characteristics.

  6. A new record of Scylla olivacea (Dcapoda, Bachyura, Prtunidae) from Goa, central west coast of India – A comparative diagnosis

    Digital Repository Service at National Institute of Oceanography (India)

    Padate, V.P.; Rivonker, C.U.; Anil, A

    Taxonomic studies on mud crabs (Scylla) reveal considerable ambiguity in species identification owing to overlap of morphological characters. Present study consists a new record of Scylla olivacea along with a comparative diagnosis with S. serrata...

  7. Head-started Kemp’s ridley turtle (Lepidochelys kempii) nest recorded in Florida: Possible implications

    Science.gov (United States)

    Shaver, Donna J.; Lamont, Margaret M.; Maxwell, Sharon; Walker, Jennifer Shelby; Dillingham, Ted

    2016-01-01

    A head-started Kemp’s ridley sea turtle (Lepidochelys kempii) was documented nesting on South Walton Beach, Florida on 25 May 2015. This record supports the possibility that exposure to Florida waters after being held in captivity through 1–3 yrs of age during the head-starting process may have influenced future nest site selection of this and perhaps other Kemp’s ridley turtles. Such findings could have important ramifications for marine water experimentation and release site selection for turtles that have been reared in captivity.

  8. REINFORCEMENT AND REPRODUCTIVE CHARACTER DISPLACEMENT IN GASTROPHRYNE CAROLINENSIS AND G. OLIVACEA (ANURA: MICROHYLIDAE): A REEXAMINATION.

    Science.gov (United States)

    Loftus-Hills, Jasper J; Littlejohn, Murray J

    1992-08-01

    Tape-recorded advertisement calls of Gastrophryne carolinensis and G. olivacea, obtained in Texas and southern Louisiana, were analyzed by means of an analogue audiospectrograph. Samples were grouped into four areas: allopatric and sympatric for G. carolinensis, and combined adjacent allopatric/shallow sympatric, and sympatric for G. olivacea. Three attributes of the advertisement call (call duration, pulse rate, and dominant frequency) were investigated, with water temperature at the calling site as the independent variable. Values for dominant frequency do not overlap between species, across the full range of recording temperatures, and those of sympatric G. carolinensis are displaced away from those of both groups of G. olivacea (which are very similar)-thus indicating a pattern of geographic variation consistent with reproductive character displacement. There is considerable overlap in the values for duration and for pulse rate of each species when considered alone, but there is only slight overlap of the scatters of points for the pairs of values. For both species, no consistent patterns of correlation were detected between the three attributes of the call and the snout-vent length of the emitter, thus reducing the likelihood that the divergence in calls is due to pleiotropic effects of body size. © 1992 The Society for the Study of Evolution.

  9. Taxonomy of Nephroselmis viridis sp. nov. (Nephroselmidophyceae, Chlorophyta), a sister marine species to freshwater N. olivacea.

    Science.gov (United States)

    Yamaguchi, Haruyo; Suda, Shoichiro; Nakayama, Takeshi; Pienaar, Richard N; Chihara, Mitsuo; Inouye, Isao

    2011-01-01

    The genus Nephroselmis (Nephroselmidophyceae), which had been placed in the Prasinophyceae, is one of the primitive green flagellates that are important to our understanding of the early evolution of green plants. We studied a new species of Nephroselmis isolated from Japan, Fiji and South Africa. This species has been known for a long time as undescribed species 'N. viridis.' N. viridis possesses some ultrastructural characters shared with only the freshwater type species N. olivacea, including a disc-like structure beneath the pyrenoid and bipolar spiny body scales with 1-5-8-5-1 spines. Molecular phylogenetic analysis based on 18S rDNA also supports a sister relationship between N. viridis and N. olivacea. However, N. viridis is distinguishable from N. olivacea by the shape of its starch sheath, its scales, its pigment composition and its habitat. In this paper, we designate the formal description of N. viridis sp. nov. We also describe variability in the 18S rDNA introns of various N. viridis strains. This detailed study of N. viridis provides some insights into the evolution of Nephroselmis.

  10. Multilocus ISSR Markers Reveal Two Major Genetic Groups in Spanish and South African Populations of the Grapevine Fungal Pathogen Cadophora luteo-olivacea

    NARCIS (Netherlands)

    Gramaje, D.; Leon, M.; Santana, M.; Crous, P.W.; Armengol, J.

    2014-01-01

    Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied.

  11. Multilocus ISSR markers reveal two major genetic groups in Spanish and South African populations of the grapevine fungal pathogen Cadophora luteo-olivacea

    NARCIS (Netherlands)

    Gramaje, David; León, Maela; Santana, Marcela; Crous, Pedro W; Armengol, Josep

    2014-01-01

    Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied.

  12. Foraging dynamics and pollination efficiency of Apis mellifera and Xylocopa olivacea on Luffa aegyptiaca Mill (Cucurbitaceae in southern Ghana

    Directory of Open Access Journals (Sweden)

    Mensah, Ben

    2011-05-01

    Full Text Available As a result of different levels of pollination efficiency of pollinators, knowledge on appropriate pollinators of a plant has become important, especially in the management and conservation of both the pollinators and the plants. In this study, the pollination efficiency of Apis mellifera and Xylocopa olivacea, important pollinators of Luffa aegyptiaca, were assessed in the southern coastal part of Ghana from June 2009 to September 2010. Pollination efficiency of A. mellifera and X. olivacea was estimated in terms of fruit set and fruit size. Further, data on daily and seasonal nectar dynamics of Luffa aegyptiaca were collected. In the early mornings (0600-0700, X. olivacea was the most frequent visitor (0.47 min-1 on the female flowers compared to A. mellifera (0.13 min-1. The mean nectar (sugar concentration in the dry season was 36.58 ± 0.55 %, which was higher than the 34.03 ± 0.38 % obtained for the rainy season (F = 14.986; df = 2; P χ2 = 14.33, df = 1, P X. olivacea had a mean weight of 428.7g and were 1.5 times heavier than fruits from flowers visited by A. mellifera (286.76 g. X. olivacea was more efficient than A. mellifera in terms of number of fruit set per single visit. This study has provided some knowledge on pollination ecology of L. aegyptiaca, which can be exploited to improve fruit production in commercially grown vine crops.

  13. Environmental Impact Analysis Process. Final Environmental Assessment Construction and Operation of Revised PACBAR III Radar Station Saipan, CNMI

    Science.gov (United States)

    1987-06-25

    Lepidochelys olivacea T Monitor Lizard (Iguana) Varanos indicus P (3) _____________________ (1) P CNMI Protected (Limited...Turtle Enetmochelys imbricata E Leatherback Turtle Dermochelys coriacea E Ridley Turtle Lepidochelys kempii E

  14. 77 FR 41198 - Endangered Species; Marine Mammals; Receipt of Applications for Permit

    Science.gov (United States)

    2012-07-12

    ... turtle (Chelonia mydas), and olive ridley sea turtle (Lepidochelys olivacea) for the purpose of... and incidentally captured, and captive-held animals of Kemp's ridley sea turtle (Lepidochelys kempii...

  15. 78 FR 5481 - Endangered Species; Marine Mammals; Receipt of Applications for Permit

    Science.gov (United States)

    2013-01-25

    ... imbricata), green sea turtle (Chelonia mydas), Kemp's ridley sea turtle (Lepidochelys kempii), and olive ridley sea turtle (Lepidochelys olivacea) for the purpose of scientific research. Samples are to be...

  16. Pacific Missile Range Facility Intercept Test Support. Environmental Assessment/Overseas Environmental Assessment

    Science.gov (United States)

    2010-04-01

    imbricata Hawksbill sea turtle E Lepidochelys olivacea Olive ridley sea turtle T Birds Oceanodroma castro Band-rumped storm-petrel C Phoebastria albatrus...mydas Green sea turtle T Dermochelys coriacea Leatherback sea turtle E Eretmochelys imbricata Hawksbill sea turtle E Lepidochelys olivacea Olive...Hawaiian Islands: the green, hawksbill, loggerhead (Caretta caretta), olive ridley ( Lepidochelys olivacea ), and leatherback sea turtles. 3-82 PMRF

  17. Replacement of F-15 Aircraft with F-22A Aircraft Hickam Air Force Base, Hawaii Environmental Assessment

    Science.gov (United States)

    2007-09-01

    Endangered Olive ridley turtle Lepidochelys olivacea Threatened 3.7 Cultural Resources 3.7.1 Definition of Resource Cultural resources are... Lepidochelys olivacea Threatened Adults from western and Eastern Pacific may converge in Hawaiian waters. Nesting in Hawaii extremely rare. Adults feed on...Pacific_Loggerhead_Recovery_Plan.pdf _____ . 1998e. Recovery Plan for U.S. Pacific Populations of the Olive Ridley Turtle ( Lepidochelys olivacea ). NOAA National Marine

  18. Final Environmental Impact Statement/Environmental Impact Report for the California Acoustic Thermometry of Ocean Climate Project and its associated Marine Mammal Research Program. Volume 1

    Science.gov (United States)

    1995-04-01

    Lepidochelys olivacea ), and loggerhead (Caretta caretta) turtles (Eckert, pers. comm., 1990). These species are known to occur in proximity to the MBNMS, with...Olive Ridley Turtle LepIdochelys olivacea FT Loggerhead Turtle Caretta caretta FT Fish Winter-Run Chinook Salmon I Oncorhyncus ishawytcha SF, FE FE...M. Robles. 1989. V informe de trabajo "Investigacion y conservation de las tortugas laud (Dermochelys coriacea) y golfima ( Lepidochelys olivacea ) en

  19. Final Environmental Assessment for Hypersonic Technology Vehicle 2 Flight Tests

    Science.gov (United States)

    2009-04-28

    Dermochelys imbricata), loggerhead sea turtles (Caretta caretta), and olive ridley sea turtles ( Lepidochelys olivacea ), as well as blue whales...Recovery Plan for U.S. Pacific Populations of the Olive Ridley Turtle ( Lepidochelys olivacea ). National Marine Fisheries Service, Silver Spring, MD...5yeaneview.pdf ---. 2007e. Olive Ridley Turtle ( Lepidochelys olivacea ). 5-Year Review: Summary and Evaluation. 64 pp. http://www.nmfs.noaa.gov/pr/pdfs

  20. Missile Defense Agency Ballistic Missile Defense System (BMDS): Programmatic Environmental Impact Statement. Volume 2. Appendices A - J

    Science.gov (United States)

    2007-01-01

    The loggerhead (Caretta caretta), Kemp’s ridley ( Lepidochelys kempi), green (Chelonia mydeas), Olive ridley ( Lepidochelys olivacea ), green (Chelonia...Name) Threatened (T) or Endangered (E) Atlantic Ridley Turtle ( Lepidochelys kempi) E Reptiles and Amphibians American Crocodile (Crocodylus...leatherback (Dermochelys coriacea), loggerhead (Caretta caretta), and Atlantic Ridley turtle ( Lepidochelys kempi). No Federally listed threatened and

  1. Oyster Shell Dredging in Atchafalaya Bay and Adjacent Waters, Louisiana. Draft Environmental Impact Statement and Appendixes,

    Science.gov (United States)

    1987-04-01

    Rabalais and Rabalais 1980. Hughes, G.R. 1972. The olive ridley sea-turtle ( Lepidochelys olivacea ) in South-east Africa. Biol. Cons. 4(2):128-134. In... Lepidochelys kenpi (Garman 1880), undoubtedly the most endangered marine turtle tod with notes on the current status of Lepidochelys olivacea ). Bull. Maryland...Kemp’s (Atlantic) ridley turtle ( Lepidochelys kemi) and the loggerhead sea turtle (Caretta caretta). Neither species has been sighted in the immediate

  2. Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis

    Science.gov (United States)

    2012-04-01

    al. (2010) Lepidochelys kempii Kemp’s ridley turtle 6.25 McVey and Wibbels (1984) and Caillouet, Koi et al. (1986) Lepidochelys olivacea Olive...Ridley Lepidochelys olivacea in Captivity." Bulletin of Central Marine Fisheries Research Institute 35: 46-54. Reeves, R. R., B. S. Stewart, et al...Kemp’s Ridley Sea Turtles ( Lepidochelys kempii) Following Release. NOAA Technical Memorandum NMFS- SEFSC-186: 34. Caldwell, D. K. and M. C. Caldwell

  3. Identification of genes associated with reproduction in the Mud Crab (Scylla olivacea) and their differential expression following serotonin stimulation.

    Science.gov (United States)

    Kornthong, Napamanee; Cummins, Scott F; Chotwiwatthanakun, Charoonroj; Khornchatri, Kanjana; Engsusophon, Attakorn; Hanna, Peter J; Sobhon, Prasert

    2014-01-01

    The central nervous system (CNS) is often intimately involved in reproduction control and is therefore a target organ for transcriptomic investigations to identify reproduction-associated genes. In this study, 454 transcriptome sequencing was performed on pooled brain and ventral nerve cord of the female mud crab (Scylla olivacea) following serotonin injection (5 µg/g BW). A total of 197,468 sequence reads was obtained with an average length of 828 bp. Approximately 38.7% of 2,183 isotigs matched with significant similarity (E value olivacea.

  4. The natural diet of the mud crab Scylla olivacea (Herbst, 1896) in Pichavaram mangroves, India.

    Science.gov (United States)

    Viswanathan, C; Raffi, S M

    2015-11-01

    Food and feeding habits of mud crab Scylla olivacea (Herbst, 1896) in Pichavaram mangroves was investigated quantitatively and qualitatively for a period of two years from June 2010 to May 2012. Gut contents from 1737 specimens comprising 843 males and 894 females in the size range between 45 mm and 148 mm were examined. Crustaceans form the predominant food item in a majority of size groups in terms of percentage wet weight and frequency of occurrence, while molluscs showed a preference in few size groups. The other dietary items includes fishes, detritus, mud and sand and miscellaneous. Gut content analysis revealed no significant variation between the quantities of food consumed by both sexes. Feeding intensity was higher in juveniles and subadults of both sexes than that of adults, revealing a greater preference to feed on fast moving prey such as crustaceans and fishes. The results of the present study indicate that S. olivacea in Pichavaram mangroves exhibited a clear preference for crustaceans.

  5. Infestation of parasitic rhizocephalan barnacles Sacculina beauforti (Cirripedia, Rhizocephala in edible mud crab, Scylla olivacea

    Directory of Open Access Journals (Sweden)

    Khor Waiho

    2017-06-01

    Full Text Available Screening of mud crab genus Scylla was conducted in four locations (Marudu Bay, Lundu, Taiping, Setiu representing Malaysia. Scylla olivacea with abnormal primary and secondary sexual characters were prevalent (approximately 42.27% of the local screened S. olivacea population in Marudu Bay, Sabah. A total of six different types of abnormalities were described. Crabs with type 1 and type 3 were immature males, type 2 and type 4 were mature males, type 5 were immature females and type 6 were mature females. The abdomen of all crabs with abnormalities were dented on both sides along the abdomen’s middle line. Abnormal crabs showed significant variation in their size, weight, abdomen width and/or gonopod or pleopod length compared to normal individuals. The mean body weight of abnormal crabs (type 1–5 were higher than normal crabs with smaller body size, while females with type 6 abnormality were always heavier than the normal counterparts at any given size. Sacculinid’s externa were observed in the abdomen of crabs with type 4 and type 6 abnormalities. The presence of embryos within the externa and subsequent molecular analysis of partial mitochondrial COI region confirmed the rhizocephalan parasite as Sacculina beauforti. Future in-depth descriptions of the life cycle and characteristics of S. beauforti are recommended as it involves a commercially important edible crab species and the effect on human health from the consumption of crabs is of crucial concern.

  6. PENGARUH HORMON ECDYSON TERHADAP SINTASAN DAN PERIODE MOULTING PADA LARVA KEPITING BAKAU Scylla olivacea

    Directory of Open Access Journals (Sweden)

    Sutia Budi

    2018-01-01

    Full Text Available Kepiting Bakau Scylla olivacea merupakan salah satu komoditas perikanan yang memiliki nilai ekonomis yang sangat tinggi. Kendala yang dihadapi dalam kegiatan perbenihan kepiting bakau adalah masih tingginya tingkat mortalitas. Tujuan penelitan untuk mengevaluasi pengaruh hormon ecdyson terhadap sintasan dan periode moulting pada larva kepiting bakau Scylla olivacea. Penelitian dilakukan di Unit Stasiun Pembenihan Kepiting Maranak Balai Riset Perikanan Budidaya Air Payau dan Penyuluhan Perikanan (BRPBAP3 Maros, Provinsi Sulawesi Selatan. Hewan uji berupa larva kepiting bakau Scylla spp. stadia zoea. Pakan uji dalam penelitian berupa rotifer dan Artemia yang dilakukan pengkayaan dengan hormon ecdyson. Wadah penelitian berupa akuarium 110 L berjumlah 12 buah yang diisi dengan air sebanyak 100 L, air bersalinitas 28-30 ppt dengan kepadatan larva sebanyak 50 ekor/L. Perlakuan yang diuji adalah berbagai dosis hormon ecdyson dalam pakan, yakni A= 0 mg/L; B= 0,5 mg/L; C= 1 mg/L; dan D= 1,5 mg/L; dengan tiga kali ulangan. Parameter yang diukur adalah sintasan dan periode moulting. Hasil penelitian menunjukkan bahwa perlakuan dosis hormon ecdyson memberikan pengaruh yang baik terhadap sintasan dan periode moulting larva kepiting bakau. Mud crab, Scylla olivacea is one of highly valued and sought-after fishery commodities. Despite its high economic value, mud crab culture still faces a problem in producing high-quality seed which is high mortality rate post-spawning. The study aim was to evaluate the effect of the Ecdyson hormone on the survival rate and molting period of the mud crab larvae. The study was conducted at the Maranak Crab Seedling, BRPBAP3 Maros, South Sulawesi Province. The trial used mud crabs larvae that were in zoea stage. The trial feed was given in the form of Rotifer and Artemia enriched with the Ecdyson hormone. Twelve 110-liter aquaria were filled with 100 L of 28-30 ppt of seawater. The stocking density of mud crab seed was 50

  7. Tendencia poblacional y éxito de eclosión de las anidaciones masivas de tortugas lora (Lepidochelys olivacea Eschscholtz 1829) en el Refugio Nacional de Vida Silvestre de Ostional, Guanacaste

    OpenAIRE

    Chaves Cordero, Gerardo Antonio

    2007-01-01

    Tesis (magíster scientiae en biología)--Universidad de Costa Rica. Sistema de Estudios de Posgrado, 2007. UCR::Investigación::Sistema de Estudios de Posgrado::Ciencias Básicas::Maestría Académica en Biología

  8. Lipase-mediated production of defensive toxins in the marine mollusc Oxynoe olivacea.

    Science.gov (United States)

    Cutignano, Adele; Notti, Valentina; d'Ippolito, Giuliana; Coll, Anna Domenech; Cimino, Guido; Fontana, Angelo

    2004-11-07

    Metabolites related to caulerpenyne (1), a toxic sesquiterpene featured by two enol-acetate residues, play a major role in the chemical defence of both algae of the genus Caulerpa and a few molluscs of the order Sacoglossa. Here we report the direct evidence that cell-free preparations of Oxynoe olivacea, a Mediterranean sacoglossan, transform efficiently the algal metabolite 1 to oxytoxin-2 (3), the main defensive metabolite of the mollusc. The process implies two distinct hydrolytic activities, here named LIP-1 and LIP-2, able to operate either hydrolysis of the acetyl residue at C-1 or concerted elimination of the acetyl groups at C-4 and C-13. Incubation experiments with tissue homogenates of O. olivacea or with commercially available lipases suggest a two-step mechanism that involves, in vitro, an unstable metabolite characterized as preoxytoxin-2 (4). The course of the entire process can be easily monitored by reverse phase HPLC/ESI-MS, as well as by NMR measurements, which provides direct evidence of the enzymatic mechanism leading to the formation of this last compound (4). In agreement with the literature, both fresh and frozen tissues of Mediterranean Caulerpa prolifera also have the capability to transform 1 into aldehydic derivatives, namely oxytoxin-1 (2) and oxytoxin-2 (3), through hydrolysis of the acetyl groups. However, differently from experiments with mollusc homogenates, the conversion is not complete and caulerpenyne (1) can be detected in the algal suspension for a few hours. HPLC/ESI-MS monitoring of this transformation suggests that the hydrolytic route involves different activities in the mollusc and seaweed.

  9. Rapid range expansion in the Great Plains narrow-mouthed toad (Gastrophryne olivacea) and a revised taxonomy for North American microhylids.

    Science.gov (United States)

    Streicher, Jeffrey W; Cox, Christian L; Campbell, Jonathan A; Smith, Eric N; de Sá, Rafael O

    2012-09-01

    We investigated genetic variation within the Great Plains narrow-mouthed toad, Gastrophryne olivacea, across its geographic range in the United States and Mexico. An analysis of mitochondrial DNA (mtDNA) from 105 frogs revealed remarkably low levels of genetic diversity in individuals inhabiting the central United States and northern Mexico. We found that this widespread matrilineal lineage is divergent (ca. 2% in mtDNA) from haplotypes that originate from the western United States and western coast of Mexico. Using a dataset that included all five species of Gastrophryne and both species of the closely related genus Hypopachus, we investigated the phylogenetic placement of G. olivacea. This analysis recovered strong support that G. olivacea, the tropically distributed G. elegans, and the temperately distributed G. carolinensis constitute a monophyletic assemblage. However, the placement of G. pictiventris and G. usta render Gastrophryne paraphyletic with respect to Hypopachus. To complement our mitochondrial analysis, we examined a small fragment of nuclear DNA and recovered consistent patterns. In light of our findings we recommend (1) the resurrection of the nomen G. mazatlanensisTaylor (1943) for the disjunct western clade of G. olivacea and (2) the tentative placement of G. pictiventris and G. usta in Hypopachus. To explore possible scenarios leading to low levels of genetic diversity in G. olivacea, we used mismatch distributions and Bayesian Skyline plots to examine historic population expansion and demography. Collectively these analyses suggest that G. olivacea rapidly expanded in effective population size and geographic range during the late Pleistocene or early Holocene. This hypothesis is consistent with fossil data from northern localities and contemporary observations that suggest ongoing northern expansion. Given our findings, we suspect that the rapid range expansion of G. olivacea may have been facilitated by ecological associations with open

  10. The ontogeny of morphological defenses in Kemp's ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtles.

    Science.gov (United States)

    Salmon, Michael; Higgins, Benjamin; Stewart, Joshua; Wyneken, Jeanette

    2015-08-01

    Marine turtles are large reptiles that compensate for high juvenile mortality by producing hundreds of hatchlings during a long reproductive lifespan. Most hatchlings are taken by predators during their migration to, and while resident in, the open ocean. Their survival depends upon crypticity, minimizing movement to avoid detection, and foraging efficiently to grow to a size too difficult for predators to either handle or swallow. While these behavioral antipredator tactics are known, changes in morphology accompanying growth may also improve survival prospects. These have been only superficially described in the literature. Here, we compare the similarities and differences in presumed morphological defenses of growing loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) posthatchlings, related species that differ in growth rate, timing of habitat shift (the return from oceanic to neritic locations), and size at maturity. In both species, vertebral spination and carapace widening increase disproportionally as small turtles grow, but later in ontogeny, the spines regress, sooner in ridley than in loggerhead turtles. Carapace widening occurs in both species but loggerheads are always longer than they are wide whereas in Kemp's ridley turtles, the carapace becomes as wide as long. Our analysis indicates that these changes are unrelated to when each species shifts habitat but are related to turtle size. We hypothesize that the spines function in small turtles as an early defense against gape-limited predators, but changes in body shape function throughout ontogeny-initially to make small turtles too wide to swallow and later by presenting an almost flat and hardened surface that large predators (such as a sharks) are unable to grasp. The extremely wide carapace of the Kemp's ridley may compensate for its smaller adult size (and presumed greater vulnerability) than the loggerhead. © 2015 Wiley Periodicals, Inc.

  11. Ophthalmic variables in rehabilitated juvenile Kemp's ridley sea turtles (Lepidochelys kempii).

    Science.gov (United States)

    Gornik, Kara R; Pirie, Christopher G; Marrion, Ruth M; Wocial, Julika N; Innis, Charles J

    2016-03-15

    To determine central corneal thickness (total corneal thickness [TCT], epithelial thickness [ET], and stromal thickness [ST]), anterior chamber depth (ACD), and intraocular pressure (IOP) in Kemp's ridley sea turtles (Lepidochelys kempii). Prospective cross-sectional study. 25 healthy rehabilitated juvenile Kemp's ridley sea turtles. PROCEDURES; Body weight and straight-line standard carapace length (SCL) were recorded. All turtles underwent a complete anterior segment ophthalmic examination. Central TCT, ET, ST, and ACD were determined by use of a spectral-domain optical coherence tomography device. Intraocular pressure was determined with a rebound tonometer; the horse setting was used to measure IOP in all 25 turtles, and the undefined setting was also used to measure IOP in 20 turtles. For each variable, 3 measurements were obtained bilaterally. The mean was calculated for each eye and used for analysis purposes. The mean ± SD body weight and SCL were 3.85 ± 1.05 kg (8.47 ± 2.31 lb) and 29 ± 3 cm, respectively. The mean ± SD TCT, ET, ST, and ACD were 288 ± 23 μm, 100 ± 6 μm, 190 ± 19 μm, and 581 ± 128 μm, respectively. Mean ± SD IOP was 6.5 ± 1.0 mm Hg when measured with the horse setting and 3.8 ± 1.1 mm Hg when measured with the undefined setting. Results provided preliminary reference ranges for objective assessment of ophthalmic variables in healthy juvenile Kemp's ridley sea turtles.

  12. Final Environmental Impact Statement Evolved Expendable Launch Vehicle Program

    Science.gov (United States)

    1998-04-01

    turtle Chelonia mydas T - Loggerhead sea turtle Caretta caretta T - Pacific Ridley sea turtle Lepidochelys olivacea T - Leatherback sea turtle...turtle Lepidochelys olivacea Gopher snake Pituophis melanoleucus Pacific chorus frog Psuedacris regilla California red-legged frog Rana aurora...coriacea E E Atlantic (Kemp’s) Ridley sea turtle Lepidochelys kempi E E Hawksbill sea turtle Eretmochelys imbricata imbricata E E Birds Wood stork

  13. Environmental Impact Analysis Process. Supplement to Final Environmental Impact Statement Space Shuttle Program, Vandenberg AFB, California

    Science.gov (United States)

    1983-07-01

    ridley sea turtle ( Lepidochelys olivacea ) are occasionally found in the area and are listed as threatened. Section 7 of the BSA requires federal agencies... Lepidochelys olivacea ) are occasionally found in the area and are listed as threatened. Section 7 of the ESA requires federal agencies to consider...turtle (Eretmochelys imbricata brissa) Green sea turtle (Chelonia sydas) Loggerhead sea turtle (Caretta caretta) Pacific Ridley sea turtle ( Lepidochelys

  14. Environmental Analysis of U.S. Navy Shipboard Solid Waste Discharges: Addendum to the Report of Findings.

    Science.gov (United States)

    1999-02-01

    Ridley turtle, Lepidochelys olivacea , and the leatherback sea turtle, Dermochelys coriacea, are also rare in the Red Sea. The olive Ridley apparently...the green turtle, Chelonia mydas; the loggerhead turtle, Caretta caretta; the olive Ridley turtle, Lepidochelys olivacea ; and the leatherback...assessed based on their potential for exposure to solid wastes. Kemp’s (Atlantic) Ridley Sea Turtle ( Lepidochelys kempii). Adults are restricted to the Gulf

  15. Oyster Shell Dredging in Atchafalaya Bay and Adjacent Waters, Louisiana. Volume 1. Final Environment Impact Statement and Appendixes.

    Science.gov (United States)

    1987-11-01

    1972. The olive ridley sea-turtle ( Lepidochelys olivacea ) in South-east Africa. Biol. Cons. 4(2):128-134. In Frazier 1980. Joyce, J.C. 1982. Protecting...turtle today (with notes on the current status of Lepidochelys olivacea ). Bull. Maryland Herp. Soc. 13:170-192. Not cited in text, but included as...dredging activities, Kemp’s (Atlantic) ridley turtle ( Lepidochelys kempi) and the loggerhead sea turtle (Caretta caretta). Neither species has been sighted

  16. Clam Shell Dredging in Lakes Pontchartrain and Maurepas, Louisiana. Volume 1. Final Environmental Impact Statement and Appendixes

    Science.gov (United States)

    1987-11-01

    Lepidochelys olivacea ) in South-east Africa. Biol. Cons. 4(2):128-134. In Frazier 1980. Joyce, J.C. 1982. Protecting sea turtles while dredging. Military...turtle today (with notes on the current status of Lepidochelys olivacea ). Bull. Maryland Herp. Soc. 13:170-192. * Not cited in text, but included as...that may be potentially impacted by the proposed activity are the Kemp’s (Atlantic) ridley sea turtle, Lepidochelys kempi, which is endangered, and

  17. Environmental Assessment/Overseas Environmental Assessment for the F-35 Joint Strike Fighter Initial Operational Test and Evaluation

    Science.gov (United States)

    2009-09-01

    Lepidochelys olivacea ). At least 34 species of cetaceans have been identified in the SCB. At least nine species generally can be found in the...couperi Eastern indigo snake Threatened Eretmochelys imbricata imbricata Hawksbill turtle Endangered Lepidochelys kempii Kemp’s ridley turtle...imbricata Hawksbill turtle Endangered Lepidochelys kempii Kemp’s ridley turtle Endangered Birds Calidris canutus Red knot Candidate Charadrius

  18. Assessment of ground transportation stress in juvenile Kemp’s ridley sea turtles (Lepidochelys kempii)

    Science.gov (United States)

    Hunt, Kathleen E.; Innis, Charles J.; Kennedy, Adam E.; McNally, Kerry L.; Davis, Deborah G.; Burgess, Elizabeth A.; Merigo, Constance

    2016-01-01

    Sea turtle rehabilitation centres frequently transport sea turtles for long distances to move animals between centres or to release them at beaches, yet there is little information on the possible effects of transportation-related stress (‘transport stress’) on sea turtles. To assess whether transport stress is a clinically relevant concern for endangered Kemp’s ridley sea turtles (Lepidochelys kempii), we obtained pre-transport and post-transport plasma samples from 26 juvenile Kemp’s ridley sea turtles that were transported for 13 h (n = 15 turtles) or 26 h (n = 11 turtles) by truck for release at beaches. To control for effects of handling, food restriction and time of day, the same turtles were also studied on ‘control days’ 2 weeks prior to transport, i.e. with two samples taken to mimic pre-transport and post-transport timing, but without transportation. Blood samples were analysed for nine clinical health measures (pH, pCO2, pO2, HCO3, sodium, potassium, ionized calcium, lactate and haematocrit) and four ‘stress-associated’ parameters (corticosterone, glucose, white blood cell count and heterophil-to-lymphocyte ratio). Vital signs (heart rate, respiratory rate and cloacal temperature) were also monitored. Corticosterone and glucose showed pronounced elevations due specifically to transportation; for corticosterone, this elevation was significant only for the longer transport duration, whereas glucose increased significantly after both transport durations. However, clinical health measures and vital signs showed minimal or no changes in response to any sampling event (with or without transport), and all turtles appeared to be in good clinical health after both transport durations. Thus, transportation elicits a mild, but detectable, adrenal stress response that is more pronounced during longer durations of transport; nonetheless, Kemp’s ridley sea turtles can tolerate ground transportation of up to 26 h in good health. These

  19. Neuronal classification and distribution in the central nervous system of the female mud crab, Scylla olivacea.

    Science.gov (United States)

    Kornthong, Napamanee; Tinikul, Yotsawan; Khornchatri, Kanjana; Saeton, Jirawat; Magerd, Sirilug; Suwansa-Ard, Saowaros; Kruangkum, Thanapong; Hanna, Peter J; Sobhon, Prasert

    2014-03-01

    The mud crab, Scylla olivacea, is one of the most economically valuable marine species in Southeast Asian countries. However, commercial cultivation is disadvantaged by reduced reproductive capacity in captivity. Therefore, an understanding of the general and detailed anatomy of central nervous system (CNS) is required before investigating the distribution and functions of neurotransmitters, neurohormones, and other biomolecules, involved with reproduction. We found that the anatomical structure of the brain is similar to other crabs. However, the ventral nerve cord (VNC) is unlike other caridian and dendrobrachiate decapods, as the subesophageal (SEG), thoracic and abdominal ganglia are fused, due to the reduction of abdominal segments and the tail. Neurons in clusters within the CNS varied in sizes, and we found that there were five distinct size classes (i.e., very small globuli, small, medium, large, and giant). Clusters in the brain and SEG contained mainly very small globuli and small-sized neurons, whereas, the VNC contained small-, medium-, large-, and giant-sized neurons. We postulate that the different sized neurons are involved in different functions. Copyright © 2013 Wiley Periodicals, Inc.

  20. Underreplication of a polytene chromosome arm in the chironomid Prodiamesa olivacea.

    Science.gov (United States)

    Zacharias, H

    1979-04-05

    The genome of Prodiamesa olivacea (Diptera, Chironomidae) has a 2 CDNA content of 0.25 pg. Mitotic metaphases reveal 3 pairs of chromosomes: 2 metacentric ones and one submetacentric. The latter comprises 20.8% of total Feulgen DNA. During larval polytenization the complemental portion of the 3rd falls to 6.5%. Concomitantly the polytene 3rd chromosome is much shorter than expected. It has no constriction and is shaped like a ball sector. -- Underreplication is understood as suppression of DNA syntheses mainly in the long arm of the 3rd chromosome at the first to third endoreplicative cycle. Most of the dense heterochromatin seen in the apex of the 3rd polytene element is not itself underreplicated; it conceals the underreplicated long arm of this chromosome. -- In ovarian nurse cells which are closely connected with the germ line the longer heterochromatic arm of the 3rd polyneme chromosome is fully replicated. -- Underreplication is discussed in the context of "dna silencing".

  1. Haemoproteus cyanomitrae sp. nov. (Haemosporida: Haemoproteidae) from a widespread African songbird, the olive sunbird, Cyanomitra olivacea.

    Science.gov (United States)

    Iezhova, Tatjana A; Valkiūnas, Gediminas; Loiseau, Claire; Smith, Thomas B; Sehgal, Ravinder N M

    2010-02-01

    Haemoproteus ( Parahaemoproteus ) cyanomitrae n. sp. (Haemosporida: Haemoproteidae) was found in the olive sunbird, Cyanomitra olivacea (Nectariniidae), in rain forests of tropical Africa. It is described based on the morphology of its blood stages and a segment of the mitochondrial cytochrome b gene (GenBank accession FJ404696), which can be used for molecular identification and diagnosis of this species. Fully grown gametocytes of new parasite are similar to many other species of haemoproteids of passeriform birds, so are not easily distinguishable from many of them at this stage of their development. Haemoproteus cyanomitrae can be readily distinguished from the majority of described species of avian haemoproteids, primarily due to its growing dumbbell-shaped gametocytes and advanced halteridial gametocytes, both of which do not touch the envelope of infected erythrocytes along their entire margin. Pigment granules are most frequently clamped in 1, or several, groups in gametocytes, with larger group of pigment granules usually located close to one end of the gametocyte; asymmetric position of pigment granules in gametocytes a characteristic feature of this parasite. Illustrations of blood stages of the new species are given, and phylogenetic analysis identifies DNA lineages closely related to this parasite, which is widespread in African rain forests, but has been recorded only in the olive sunbird so far. It is probable that H. cyanomitrae is transmitted throughout the range of the olive sunbird in Africa.

  2. Transcriptome Analysis and Differential Gene Expression on the Testis of Orange Mud Crab, Scylla olivacea, during Sexual Maturation.

    Directory of Open Access Journals (Sweden)

    Khor Waiho

    Full Text Available Adequate genetic information is essential for sustainable crustacean fisheries and aquaculture management. The commercially important orange mud crab, Scylla olivacea, is prevalent in Southeast Asia region and is highly sought after. Although it is a suitable aquaculture candidate, full domestication of this species is hampered by the lack of knowledge about the sexual maturation process and the molecular mechanisms behind it, especially in males. To date, data on its whole genome is yet to be reported for S. olivacea. The available transcriptome data published previously on this species focus primarily on females and the role of central nervous system in reproductive development. De novo transcriptome sequencing for the testes of S. olivacea from immature, maturing and mature stages were performed. A total of approximately 144 million high-quality reads were generated and de novo assembled into 160,569 transcripts with a total length of 142.2 Mb. Approximately 15-23% of the total assembled transcripts were annotated when compared to public protein sequence databases (i.e. UniProt database, Interpro database, Pfam database and Drosophila melanogaster protein database, and GO-categorised with GO Ontology terms. A total of 156,181 high-quality Single-Nucleotide Polymorphisms (SNPs were mined from the transcriptome data of present study. Transcriptome comparison among the testes of different maturation stages revealed one gene (beta crystallin like gene with the most significant differential expression-up-regulated in immature stage and down-regulated in maturing and mature stages. This was further validated by qRT-PCR. In conclusion, a comprehensive transcriptome of the testis of orange mud crabs from different maturation stages were obtained. This report provides an invaluable resource for enhancing our understanding of this species' genome structure and biology, as expressed and controlled by their gonads.

  3. Transcriptome Analysis and Differential Gene Expression on the Testis of Orange Mud Crab, Scylla olivacea, during Sexual Maturation.

    Science.gov (United States)

    Waiho, Khor; Fazhan, Hanafiah; Shahreza, Md Sheriff; Moh, Julia Hwei Zhong; Noorbaiduri, Shaibani; Wong, Li Lian; Sinnasamy, Saranya; Ikhwanuddin, Mhd

    2017-01-01

    Adequate genetic information is essential for sustainable crustacean fisheries and aquaculture management. The commercially important orange mud crab, Scylla olivacea, is prevalent in Southeast Asia region and is highly sought after. Although it is a suitable aquaculture candidate, full domestication of this species is hampered by the lack of knowledge about the sexual maturation process and the molecular mechanisms behind it, especially in males. To date, data on its whole genome is yet to be reported for S. olivacea. The available transcriptome data published previously on this species focus primarily on females and the role of central nervous system in reproductive development. De novo transcriptome sequencing for the testes of S. olivacea from immature, maturing and mature stages were performed. A total of approximately 144 million high-quality reads were generated and de novo assembled into 160,569 transcripts with a total length of 142.2 Mb. Approximately 15-23% of the total assembled transcripts were annotated when compared to public protein sequence databases (i.e. UniProt database, Interpro database, Pfam database and Drosophila melanogaster protein database), and GO-categorised with GO Ontology terms. A total of 156,181 high-quality Single-Nucleotide Polymorphisms (SNPs) were mined from the transcriptome data of present study. Transcriptome comparison among the testes of different maturation stages revealed one gene (beta crystallin like gene) with the most significant differential expression-up-regulated in immature stage and down-regulated in maturing and mature stages. This was further validated by qRT-PCR. In conclusion, a comprehensive transcriptome of the testis of orange mud crabs from different maturation stages were obtained. This report provides an invaluable resource for enhancing our understanding of this species' genome structure and biology, as expressed and controlled by their gonads.

  4. Oxytoxins, bioactive molecules produced by the marine opisthobranch mollusc Oxynoe olivacea from a diet-derived precursor.

    Science.gov (United States)

    Cimino, G; Crispino, A; Di Marzo, V; Gavagnin, M; Ros, J D

    1990-07-15

    The ethereal extract of the mucous secretion from the opisthobranch mollusc Oxynoe olivacea was examined and found to contain two novel ichthyotoxic compounds, named oxytoxin 1 and 2 (1,2). The structures of 1 and 2 are closely related to the metabolites previously isolated from the alga Caulerpa prolifera. The activity of the most stable compound was studied in order to investigate the possibility of a further biological role for these metabolites, which represent an uncommon example of bioactive molecules produced in vivo from a dietary precursor.

  5. PENGGUNAAN TEPUNG DAUN MURBEI (Morus alba L DALAM PAKAN PEMBESARAN KEPITING BAKAU, Scylla olivacea

    Directory of Open Access Journals (Sweden)

    Kamaruddin Kamaruddin

    2018-01-01

    Full Text Available Salah satu bahan nabati yang perlu dievaluasi sebagai bahan pakan untuk kepiting bakau adalah daun murbei yang mengandung protein cukup tinggi dan hormone ecdisterone yang penting untuk proses molting krustase. Tujuan penelitian ini adalah untuk mendapatkan dosis optimum penggunaan tepung daun murbei dalam pakan pembesaran kepiting bakau, Scylla olivacea. Juvenil kepiting bakau yang digunakan terdiri atas 3 kelompok ukuran bobot yaitu (i 36±1,9 g; (ii 45±1,5 g; dan (iii 63±3,9 g. Perlakuan yang dicobakan adalah enam pakan dengan kandungan tepung daun murbei yang berbeda yaitu: 0%(DM0; 10% (DM10; 12,5% (DM12,5; 15% (DM15; 17,5% (DM17,5; dan 20% (DM20. Wadah penelitian yang digunakan berupa kotak kepiting (crab box sebanyak 90 buah, diisi sebanyak 1 ekor/boks, dan didisain dengan rancangan acak kelompok. Pemberian pakan uji dilakukan dua kali sehari pukul 08.00 dan pukul 17.00 sebanyak 3-4% dari biomassa per hari. Hasil penelitian menunjukkan bahwa laju pertumbuhan spesifik (bobot, lebar karapas, dan panjang karapas, serta sintasan kepiting, rasio konversi pakan, dan efisiensi protein pakan, tidak berbeda nyata (P>0,05 antar perlakuan. Namun kandungan tepung daun murbei dalam pakan di atas 15% menurunkan nilai koefisien kecernaan total pakan, dan kandungan tepung murbei di atas 17,5% menurunkan nilai kecernaan protein pakan. Berdasarkan respon pertumbuhan dan nilai kecernaan pakan, tepung daun murbei dapat dimanfaatkan hingga 15% dalam pakan pembesaran kepiting bakau. One of plant ingredients suitable to be evaluated as a feed ingredient for mud crab is mulberry leaves which contains protein and ecdisteron. The purpose of this study is to obtain the optimum dose of mulberry leaf meal in grow-out diet for mud crab Scylla olivacea. Juvenile mud crabs were used consisting of 3 groups of weight size ie. (i36±1.9 g; (ii 45±1.5 g; and (iii 63±3.9 g. The treatments were six diets containing different levels of mulberry leaf at 0% (DM0; 10% (DM10

  6. Characterization of the kidney transcriptome of the South American olive mouse Abrothrix olivacea.

    Science.gov (United States)

    Giorello, Facundo M; Feijoo, Matias; D'Elía, Guillermo; Valdez, Lourdes; Opazo, Juan C; Varas, Valeria; Naya, Daniel E; Lessa, Enrique P

    2014-06-08

    The olive mouse Abrothrix olivacea is a cricetid rodent of the subfamily Sigmodontinae that inhabits a wide range of contrasting environments in southern South America, from aridlands to temperate rainforests. Along its distribution, it presents different geographic forms that make the olive mouse a good focal case for the study of geographical variation in response to environmental variation. We chose to characterize the kidney transcriptome because this organ has been shown to be associated with multiple physiological processes, including water reabsorption. Transcriptomes of thirteen kidneys from individuals from Argentina and Chile were sequenced using Illumina technology in order to obtain a kidney reference transcriptome. After combining the reads produced for each sample, we explored three assembly strategies to obtain the best reconstruction of transcripts, TrinityNorm and DigiNorm, which include its own normalization algorithms for redundant reads removal, and Multireads, which simply consist on the assembly of the joined reads. We found that Multireads strategy produces a less fragmented assembly than normalization algorithms but recovers fewer number of genes. In general, about 15000 genes were annotated, of which almost half had at least one coding sequence reconstructed at 99% of its length. We also built a list of highly expressed genes, of which several are involved in water conservation under laboratory conditions using mouse models. Based on our assembly results, Trinity's in silico normalization is the best algorithm in terms of cost-benefit returns; however, our results also indicate that normalization should be avoided if complete or nearly complete coding sequences of genes are desired. Given that this work is the first to characterize the transcriptome of any member of Sigmodontinae, a subfamily of cricetid rodents with about 400 living species, it will provide valuable resources for future ecological and evolutionary genomic analyses.

  7. Mitochondrial DNA diversity of mud crab Scylla olivacea (Portunidae) in Peninsular Malaysia: a preliminary assessment.

    Science.gov (United States)

    Rosly, Hurul Adila-Aida Mohamad; Nor, Siti Azizah Mohd; Yahya, Khairun; Naim, Darlina Md

    2013-11-01

    A primary factor in population management and wildlife conservation is the delineation of population units derived from descriptions of population genetic structure. Yet, predicting factors that influence the patterns of gene flow in a population particularly at landscape scales remains a major challenge in evolutionary biology. Here we report a population genetic study of the mud crab Scylla olivacea examined based on a 542 bp segment of the mitochondrial DNA cytochrome c oxidase I gene among 91 individuals from six localities in the west and east coast of Peninsular Malaysia. In total 55 unique haplotypes were distinguished with 45 private haplotypes and a single common haplotype shared among all populations studied. The other ten haplotypes were shared among various populations. The sharing of this haplotype reflects the connection of the mangrove areas between east and west coast of Peninsular Malaysia. High haplotype diversity (h = 0.968 ± 0.021; mean ± SD) and low nucleotide diversity (π = 0.120 ± 0.015; mean ± SD) were displayed, which may be indicative of genetic bottleneck events. No significant phylogenetic lineages were recognized using neighbour-joining and maximum parsimony methods. Hierarchical AMOVA analysis indicated that 99.33 % of the genetic variation was contained within populations and 0.67 % occurred among populations, suggesting no geographical patterning among populations studied, supported by F st test. Mismatch distribution analysis showed that the observed distribution of the pairwise mutation differences among haplotypes was multimodal, which is not concordant with a sudden range expansion scenario. However, neutrality tests showed non-significant negative values suggesting that the populations studied may have experienced past population growth, but the expansion may have been restricted to separate local areas that resulted in the non-significant negative Fu's Fs and Tajima's D value. Overall, this present preliminary study was

  8. Prediction of Scylla olivacea (Crustacea; Brachyura) peptide hormones using publicly accessible transcriptome shotgun assembly (TSA) sequences.

    Science.gov (United States)

    Christie, Andrew E

    2016-05-01

    The aquaculture of crabs from the genus Scylla is of increasing economic importance for many Southeast Asian countries. Expansion of Scylla farming has led to increased efforts to understand the physiology and behavior of these crabs, and as such, there are growing molecular resources for them. Here, publicly accessible Scylla olivacea transcriptomic data were mined for putative peptide-encoding transcripts; the proteins deduced from the identified sequences were then used to predict the structures of mature peptide hormones. Forty-nine pre/preprohormone-encoding transcripts were identified, allowing for the prediction of 187 distinct mature peptides. The identified peptides included isoforms of adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin B, allatostatin C, bursicon β, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone/molt-inhibiting hormone, diuretic hormone 31, eclosion hormone, FMRFamide-like peptide, HIGSLYRamide, insulin-like peptide, intocin, leucokinin, myosuppressin, neuroparsin, neuropeptide F, orcokinin, pigment dispersing hormone, pyrokinin, red pigment concentrating hormone, RYamide, short neuropeptide F, SIFamide and tachykinin-related peptide, all well-known neuropeptide families. Surprisingly, the tissue used to generate the transcriptome mined here is reported to be testis. Whether or not the testis samples had neural contamination is unknown. However, if the peptides are truly produced by this reproductive organ, it could have far reaching consequences for the study of crustacean endocrinology, particularly in the area of reproductive control. Regardless, this peptidome is the largest thus far predicted for any brachyuran (true crab) species, and will serve as a foundation for future studies of peptidergic control in members of the commercially important genus Scylla. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Multilocus ISSR markers reveal two major genetic groups in Spanish and South African populations of the grapevine fungal pathogen Cadophora luteo-olivacea.

    Science.gov (United States)

    Gramaje, David; León, Maela; Santana, Marcela; Crous, Pedro W; Armengol, Josep

    2014-01-01

    Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa) were studied. Inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR) generated 55 polymorphic loci from four ISSR primers selected from an initial screen of 13 ISSR primers. The ISSR markers revealed 40 multilocus genotypes (MLGs) in the global population. Minimum spanning network analysis showed that the MLGs from South Africa clustered around the most frequent genotype, while the genotypes from Spain were distributed all across the network. Principal component analysis and dendrograms based on genetic distance and bootstrapping identified two highly differentiated genetic clusters in the Spanish and South African C. luteo-olivacea populations, with no intermediate genotypes between these clusters. Movement within the Spanish provinces may have occurred repeatedly given the frequent retrieval of the same genotype in distant locations. The results obtained in this study provide new insights into the population genetic structure of C. luteo-olivacea in Spain and highlights the need to produce healthy and quality planting material in grapevine nurseries to avoid the spread of this fungus throughout different grape growing regions.

  10. Multilocus ISSR markers reveal two major genetic groups in Spanish and South African populations of the grapevine fungal pathogen Cadophora luteo-olivacea.

    Directory of Open Access Journals (Sweden)

    David Gramaje

    Full Text Available Cadophora luteo-olivacea is a lesser-known fungal trunk pathogen of grapevine which has been recently isolated from vines showing decline symptoms in grape growing regions worldwide. In this study, 80 C. luteo-olivacea isolates (65 from Spain and 15 from South Africa were studied. Inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR generated 55 polymorphic loci from four ISSR primers selected from an initial screen of 13 ISSR primers. The ISSR markers revealed 40 multilocus genotypes (MLGs in the global population. Minimum spanning network analysis showed that the MLGs from South Africa clustered around the most frequent genotype, while the genotypes from Spain were distributed all across the network. Principal component analysis and dendrograms based on genetic distance and bootstrapping identified two highly differentiated genetic clusters in the Spanish and South African C. luteo-olivacea populations, with no intermediate genotypes between these clusters. Movement within the Spanish provinces may have occurred repeatedly given the frequent retrieval of the same genotype in distant locations. The results obtained in this study provide new insights into the population genetic structure of C. luteo-olivacea in Spain and highlights the need to produce healthy and quality planting material in grapevine nurseries to avoid the spread of this fungus throughout different grape growing regions.

  11. Study on Carapace Width Growth Band Counts Relationship of Orange Mud Crab, Scylla olivacea (Herbst, 1796) from Terengganu Coastal Waters, Malaysia.

    Science.gov (United States)

    Hasyima Ismail, N; Amin Safwan, A; Fairuz Fozi, N; Megat, F H; Muhd Farouk, H; Kamaruddin, S A; Ikhwanuddin, M; Ambak, M A

    2017-01-01

    Orange mud crab Scylla olivacea is one of the most important fisheries resources. A new development in ageing technique of crustaceans has been introduced. The detection of growth band deposited in hard structure of gastric mill in the cardiac stomach are found retained after moulting process can be used as age indicator and growth estimation. This study was carried out to determine the comparison between carapace width and growth band count of S. olivacea in Malaysia. Samples were collected from Setiu Wetlands, Terengganu, Malaysia from February until August, 2016. Samples were categorized based on their morphological measurements. The mesocardiac and zygocardiac ossicles in the gastric mill of S. olivacea was dissected out and preserved in solutions and underwent a cross sectioning process. A total of 76 of wild S. olivacea ranging from 6.56 to 12.84 cm in carapace width were analysed. The growth band counts were examined for each individual and ranging from 1 to 3 band counts. A positive linear relation was observed between CW and GBC with r2 = 0.5178, polivacea in Setiu Wetlands, Terengganu, Malaysia.

  12. Characterization of Cadophora luteo-olivacea and C. melinii isolates obtained from grapevines and environmental samples from grapevine nurseries in Spain

    Directory of Open Access Journals (Sweden)

    David GRAMAJE

    2011-12-01

    Full Text Available Fifty-eight Cadophora luteo-olivacea and three C. melinii isolates were recovered from grapevines showing black vascular streaking and decline symptoms characteristic of Petri disease, and from different stages of the grapevine nursery process in Spain. The isolates were studied by means of phenotypical characterization, DNA analysis and pathogenicity tests. The morphological characters studied included conidiophore, phialide and conidial morphology. Colony characters and pigment production on MEA, PDA and OA were also examined. Phenotypical data were subjected to cluster analysis, which clearly separated C.luteo-olivacea isolates into four groups. Mating tests were performed on all possible combinations for each Cadophora species but no sexual fruiting bodies were produced. Partial sequences of the nuclear ribosomal internal transcribed spacer (ITS, beta-tubulin (BT and the elongation factor 1a (EF were analysed, but no genetic variation occurred within the C. luteo-olivacea isolates or within the C. melinii isolates in any of the regions studied. Pathogenicity tests were conducted on 1-year-old grapevine cuttings of four different rootstocksusing four C. luteo-olivacea isolates and one isolate of C. melinii. All Cadophora isolates except the C.melinii isolate caused significantly longer lesions in the xylem of grapevine rootstocks than in the controls.

  13. Identification of genes associated with reproduction in the Mud Crab (Scylla olivacea and their differential expression following serotonin stimulation.

    Directory of Open Access Journals (Sweden)

    Napamanee Kornthong

    Full Text Available The central nervous system (CNS is often intimately involved in reproduction control and is therefore a target organ for transcriptomic investigations to identify reproduction-associated genes. In this study, 454 transcriptome sequencing was performed on pooled brain and ventral nerve cord of the female mud crab (Scylla olivacea following serotonin injection (5 µg/g BW. A total of 197,468 sequence reads was obtained with an average length of 828 bp. Approximately 38.7% of 2,183 isotigs matched with significant similarity (E value < 1e-4 to sequences within the Genbank non-redundant (nr database, with most significant matches being to crustacean and insect sequences. Approximately 32 putative neuropeptide genes were identified from nonmatching blast sequences. In addition, we identified full-length transcripts for crustacean reproductive-related genes, namely farnesoic acid o-methyltransferase (FAMeT, estrogen sulfotransferase (ESULT and prostaglandin F synthase (PGFS. Following serotonin injection, which would normally initiate reproductive processes, we found up-regulation of FAMeT, ESULT and PGFS expression in the female CNS and ovary. Our data here provides an invaluable new resource for understanding the molecular role of the CNS on reproduction in S. olivacea.

  14. Infestation of parasitic rhizocephalan barnaclesSacculina beauforti(Cirripedia, Rhizocephala) in edible mud crab,Scylla olivacea.

    Science.gov (United States)

    Waiho, Khor; Fazhan, Hanafiah; Glenner, Henrik; Ikhwanuddin, Mhd

    2017-01-01

    Screening of mud crab genus Scylla was conducted in four locations (Marudu Bay, Lundu, Taiping, Setiu) representing Malaysia. Scylla olivacea with abnormal primary and secondary sexual characters were prevalent (approximately 42.27% of the local screened S. olivacea population) in Marudu Bay, Sabah. A total of six different types of abnormalities were described. Crabs with type 1 and type 3 were immature males, type 2 and type 4 were mature males, type 5 were immature females and type 6 were mature females. The abdomen of all crabs with abnormalities were dented on both sides along the abdomen's middle line. Abnormal crabs showed significant variation in their size, weight, abdomen width and/or gonopod or pleopod length compared to normal individuals. The mean body weight of abnormal crabs (type 1-5) were higher than normal crabs with smaller body size, while females with type 6 abnormality were always heavier than the normal counterparts at any given size. Sacculinid's externa were observed in the abdomen of crabs with type 4 and type 6 abnormalities. The presence of embryos within the externa and subsequent molecular analysis of partial mitochondrial COI region confirmed the rhizocephalan parasite as Sacculina beauforti . Future in-depth descriptions of the life cycle and characteristics of S. beauforti are recommended as it involves a commercially important edible crab species and the effect on human health from the consumption of crabs is of crucial concern.

  15. Pathogenicity and molecular detection of Uruguayan isolates of Greeneria uvicola and Cadophora luteo-olivacea associated with grapevine trunk diseases

    Directory of Open Access Journals (Sweden)

    Fernando NAVARRETE

    2011-12-01

    Full Text Available Normal 0 21 MicrosoftInternetExplorer4 Species from different fungal genera have been indicated as responsible for the development of trunk diseases of grapevines. Greeneria uvicola is responsible for the bitter rot of Vitis vinifera grape bunchesnear harvest, and can also attack other Vitis species. In Uruguay, G. uvicola was isolated from dead arm affected grapevines and as an endophyte from healthy canes. Cadophora luteo-olivacea is a phialophora-likeascomycete with a wide distribution that was isolated from asymptomatic wood tissues in Vitis and Petridisease-affected nursery plants in Uruguay. Pathogenicity of isolates of both species was evaluated on Vitis vinifera cv. Tannat and Cabernet Sauvignon, and rootstocks SO4 and 3309C. Specific primers were developed for the ITS rDNA region for both species. Number of plants showing discoloration, length of discoloration, number of re-isolations and amplifications confirmed the pathogenicity of G. uvicola isolates. Pathogenicityof the isolate of C. luteo-olivacea obtained from symptomatic tissues is discussed. Specific primers can be usedto detect the presence of these fungi in asymptomatic tissues.

  16. Molecular evolution in space and through time: mtDNA phylogeography of the Olive Sunbird (Nectarinia olivacea/obscura) throughout continental Africa.

    Science.gov (United States)

    Bowie, Rauri C K; Fjeldså, Jon; Hackett, Shannon J; Crowe, Timothy M

    2004-10-01

    This study constitutes the first investigation of the phylogeographic structure of a forest bird distributed throughout the montane and lowland forest biomes of Africa. The key objective was to investigate the importance of Pleistocene climatic cycles on avian diversification across Africa. The Olive Sunbird is a relatively large polytypic sunbird widely distributed throughout evergreen, montane and coastal forests in Africa. Recently, it was split into two species, the Eastern Olive Sunbird (Nectarinia olivacea) and the Western Olive Sunbird (Nectarinia obscura), based on morphological grounds. Analyses of a 395bp fragment of the mtDNA NADH subunit 3 gene with flanking tRNA sequences, from 196 individuals of N. olivacea and 86 from N. obscura indicate that genetic divergence levels are low (1.0-2.4%) across some 9000km, from Ghana in the northwest of Africa to KwaZulu-Natal in eastern South Africa. Neither currently recognized Olive Sunbird species were monophyletic using either parsimony or likelihood tree-building methods. Phi(ST) values suggested that there was less variation partitioned among species than between most neighboring regions. Genetic diversity within the N. olivacea/obscura complex was dominated by three star-like phylogenies linked to each other by a single mutational step and two subnetworks (IV and V) separated from the core star-like phylogenies (subnetworks I, II, and III) by five to six mutational steps. The dominant evolutionary mechanism shaping genetic variation within the N. olivacea/obscura complex as identified by nested-clade analyses, appears to be one of range expansion possibly out of East Africa associated with a period of forest expansion during the mid-Pleistocene, some 1.1-0.7 million years ago. Mismatch profiles suggested that secondary contact has occurred between eastern and western lineages within the Ufipa Escarpment and possibly Zimbabwe, as well as between eastern lineages in the Kenyan Highlands and northern Eastern Arc

  17. Effect of Water Salinity on the External Morphology of Ovarian Maturation Stages of Orange Mud Crab, Scylla olivacea (Herbst, 1796) in Captivity.

    Science.gov (United States)

    Amin-Safwan, A; Muhd-Farouk, H; Nadirah, M; Ikhwanuddin, M

    Mud crab from the genus Scylla are considered as one of the most demanded seafood items nowadays as their flesh has high quality, tasty and higher growth rate thus support and boosted expansion in aquaculture sector especially in Malaysia. Present study was designed to focus on the effect of water salinity on the ovarian maturation of orange mud crab, Scylla olivacea based on morphological characteristics. Samples were collected from Setiu wetlands, Terengganu, Malaysia from July-September, 2015. Ovarian maturation of S. olivacea was classified into four stages based on previous study which were: Immature (Stage 1), early mature (Stage 2), late mature (Stage 3) and fully mature (Stage 4). Morphologically as the ovary develop the colouration start to change from translucent or whitish in colour and sometimes creamy to pale yellow, follow by light orange and lastly reddish orange. Stage 1 ovary was translucent and whitish in colour, stage 2 ovary was pale yellow in colour, stage 3 was light orange and stage 4 ovary was reddish orange in colour. Gonad Somatic Index (GSI) of S. olivacea remained low at stage 1 and 2 and began to increase started at stage 3. This present study involved three different salinities treatments, which treatment 1 (10 ppt), treatment 2 (20 ppt) and treatment 3 (30 ppt). Treatment 2 produce the highest number of stage 4 ovarian maturation based on colouration and the highest GSI recorded, follow by treatment 1 and lastly treatment 3. This present study proved that salinity does affected the ovarian maturation of S. olivacea in captivity and provides important information regarding the effect of water salinity on ovarian maturation for further studies on reproductive biology of this species.

  18. Development of SCAR primers for the detection of the postharvest pathogens of kiwifruit and pome fruit Cadophora luteo-olivacea and C. malorum

    Directory of Open Access Journals (Sweden)

    DAVIDE SPADARO

    2012-01-01

    Full Text Available 800x600 Normal 0 14 false false false IT X-NONE X-NONE MicrosoftInternetExplorer4 In recent years a postharvest disease of kiwifruit, characterized by skin pitting appearing after 3 or more months of storage, and caused by C. luteo-olivacea, has been reported in most Italian packinghouses. Forty-four strains isolated from kiwifruit harvested in Italy during the period 2001-2009 were tested for their pathogenicity on kiwifruit, apple and pear. The pathogenicity tests showed that different isolates of C. luteo-olivacea were pathogenic on the three fruit species stored at 1°C for 120 days with various degree of virulence. A PCR-based method to identify the pathogen species in kiwifruit was developed. Sequencing of the internal transcribed spacer (ITS1, 5.8S gene and ITS2 region of the rDNA (ITS showed high similarity with the species C. malorum, agent of side rot of apples and pears. Variation within the ITS was used to design one reverse primer common to both species and two species specific forward primers to specifically identify isolates of C. luteo-olivacea and C. malorum. Both SCAR (sequence characterized amplified region primer pairs showed to be specific for either Cadophora species when cross-tested and assessed on other species of Cadophora or on species of typical postharvest pathogens of kiwifruit, apple and pear.

  19. Are the Mediterranean ascoglossan molluscs Oxynoe olivacea and Lobiger serradifalci suitable agents for a biological control against the invading tropical alga Caulerpa taxifolia?

    Science.gov (United States)

    Thibaut, T; Meinesz, A

    2000-05-01

    The Mediterranean ascoglossan Oxynoe olivacea and Lobiger serradifalci, which are scarce in meadows of their usual food the alga Caulerpa prolifera, have become adapted to feeding on the invading tropical alga Caulerpa taxifolia. Grazing rates are low (O. olivacea destroys only a 5-cm C. taxifolia frond in 3-7 d). The grazing rates are a function of temperature. Despite a high spawning frequency (0.25 egg-mass.day-1) and a large number of eggs released per spawning event (O. olivacea: from 2,545 to 29,128 eggs.spawning-1; L. serradifalci: from 12,112 to 48,448 eggs.spawning-1), the recruitment on Caulerpa meadows is usually low due to the hazardous pelagic development of the larvae. The possible use of these molluscs as agents of biological control against C. taxifolia appears to be possible only through an artificial enhancement of their populations after cultivation of the veligers and release of juveniles during the winter season. This means of control is discussed and compared with the possible use of tropical ascoglossan species.

  20. Zeeschildpadden in Suriname: de lederschildpad als ‘flagship species’

    NARCIS (Netherlands)

    Hilterman, M.; Goverse, E.

    2004-01-01

    Vijf van de zeven soorten zeeschildpadden komen voor in Suriname en buurlanden Guyana en Frans Guyana. De lederschildpad (Dermochelys coriacea), soepschildpad (Chelonia mydas), olijfkleurige dwergsch lidpad (Lepidochelys olivacea) en karetschilpad (Eretmochelys imbricata) leggen er hun eieren, de

  1. Southwest Mississippi Tributaries Study Area Environmental Inventory; Wildlife Resources.

    Science.gov (United States)

    1985-09-01

    Piranqa rubra) x Scarlet tanager (P. olivacea ) x Grosbeaks, cardinals, buntings - Northern cardinal (Cardinalis cardinalis) x x Blue grosbeak (Guiraca...Chelonia mydas) Atlantic loggerhead turtle (Caretta caretta) Atlantic ridley turtle ( Lepidochelys kempi) Black-knobbed sawback turtle (Graptemys

  2. Environmental Compliance Assessment System (ECAS). North Carolina Supplement

    Science.gov (United States)

    1994-09-01

    Ridley Turtle Lepidochelys kempii E Hawksbill Turtle Eretmochelys imbricala E Leatherback Turtle Dernwchelys coriacea T American Alligator Alligator...boschianum T Dwarf Filmy-fern Trichomanes petersii T Mottled Trillium Trillium discolor T Dwarf Bladderwort Utricularia olivacea E = Endangered T

  3. Habitat selection and ecological speciation in Galápagos warbler finches (Certhidea olivacea and Certhidea fusca).

    Science.gov (United States)

    Tonnis, Brandon; Grant, Peter R; Grant, B Rosemary; Petren, Kenneth

    2005-04-22

    We investigated phylogeographic divergence among populations of Galápagos warble finches. Their broad distribution, lack of phenotypic differentiation and low levels of genetic divergence make warbler finches an appropriate model to study speciation in allopatry. A positive relationship between genetic and geographical distance is expected for island taxa. Warbler finches actually showed a negative isolation by distance relationship, causing us to reject the hypothesis of distance-limited dispersal. An alternative hypothesis, that dispersal is limited by habitat similarity, was supported. We found a positive correlation between genetic distances and differences in maximum elevation among islands, which is an indicator of ecological similarity. MtDNA sequence variation revealed monophyletic support for two distinct species. Certhidea olivacea have recently dispersed among larger central islands, while some Certhidea fusca have recently dispersed to small islands at opposite ends of the archipelago. We conclude that females have chosen to breed on islands with habitats similar to their natal environment. Habitat selection is implicated as an important component of speciation of warbler finches, which is the earliest known divergence of the adaptive radiation of Darwin's finches. These results suggest that small populations can harbour cryptic but biologically meaningful variation that may affect longer term evolutionary processes.

  4. The complete mitochondrial DNA sequences of Nephroselmis olivacea and Pedinomonas minor. Two radically different evolutionary patterns within green algae.

    Science.gov (United States)

    Turmel, M; Lemieux, C; Burger, G; Lang, B F; Otis, C; Plante, I; Gray, M W

    1999-09-01

    Green plants appear to comprise two sister lineages, Chlorophyta (classes Chlorophyceae, Ulvophyceae, Trebouxiophyceae, and Prasinophyceae) and Streptophyta (Charophyceae and Embryophyta, or land plants). To gain insight into the nature of the ancestral green plant mitochondrial genome, we have sequenced the mitochondrial DNAs (mtDNAs) of Nephroselmis olivacea and Pedinomonas minor. These two green algae are presumptive members of the Prasinophyceae. This class is thought to include descendants of the earliest diverging green algae. We find that Nephroselmis and Pedinomonas mtDNAs differ markedly in size, gene content, and gene organization. Of the green algal mtDNAs sequenced so far, that of Nephroselmis (45,223 bp) is the most ancestral (minimally diverged) and occupies the phylogenetically most basal position within the Chlorophyta. Its repertoire of 69 genes closely resembles that in the mtDNA of Prototheca wickerhamii, a later diverging trebouxiophycean green alga. Three of the Nephroselmis genes (nad10, rpl14, and rnpB) have not been identified in previously sequenced mtDNAs of green algae and land plants. In contrast, the 25,137-bp Pedinomonas mtDNA contains only 22 genes and retains few recognizably ancestral features. In several respects, including gene content and rate of sequence divergence, Pedinomonas mtDNA resembles the reduced mtDNAs of chlamydomonad algae, with which it is robustly affiliated in phylogenetic analyses. Our results confirm the existence of two radically different patterns of mitochondrial genome evolution within the green algae.

  5. Distribution of serotonin and dopamine in the central nervous system of the female mud crab, Scylla olivacea (Herbst).

    Science.gov (United States)

    Khornchatri, Kanjana; Kornthong, Napamanee; Saetan, Jirawat; Tinikul, Yotsawan; Chotwiwatthanakun, Charoonroj; Cummins, Scott F; Hanna, Peter J; Sobhon, Prasert

    2015-03-01

    In crustaceans serotonin (5-HT) and dopamine (DA) are neurotransmitters that play roles in the modulation of numerous physiological functions, including reproduction. However, in the mud crab, Scylla olivacea, the distributions of 5-HT and DA in the CNS have not yet been investigated. The aim of our study was to map the distributions of these two neurotransmitters in the central nervous system (CNS) of the female of this crab during the late stage of ovarian development. We found 5-HT immunoreactivity (-ir) and DA-ir in many parts of the CNS, including the eyestalk, brain, and thoracic ganglia. In the eyestalk, 5-HT-ir was localized in the medulla terminalis (MT), hemi-ellipsoid body (HB), and protocerebral tract (PT), whereas DA-ir was present in neuronal cluster 1, the LG neuropils, and PT. In the brain, 5-HT-ir and DA-ir were detected in cells and fibers of neuronal clusters 6, 7, 8, 9, 10, 11, 14, and 15. In the ventral nerve cord, 5-HT-ir was present in neurons of the abdominal ganglia, whereas DA was only present in fibers. These spatial distributions of 5-HT and DA suggest that they may be involved in the neuromodulation of important physiological functions, including ovarian maturation, as shown in other non-crab decapods. Copyright © 2014 Elsevier GmbH. All rights reserved.

  6. The Biophysical Characteristics Of Hatching Habitat Of Lekang Turtle (Lepidhochelys olivacea) Eggs In Turtle Conservation And Education Center, Bali

    Science.gov (United States)

    Suryono; Ario, R.; Wibowo, E.; Handoyo, G.

    2018-02-01

    Lekang turtle (Lepidhochelys olivacea) is one of the fauna that is protected as an endangered population. This marine reptile was able to migrate in great distance along the Indian Ocean, the Pacific Ocean, and South East Asia. Its existence has long been threatened, either by nature or human activities that endangered the population directly or indirectly. The decreasing number of sea turtle population that nest in Bali area is one indication of the reducing number of Lekang turtle in Indonesia. If left unchecked, it will result in the loss of Lekang turtle. This study aims to determine the successful percentage of conservation techniques and Lekang turtle hatching eggs (olive ridley sea turtle) in TCEC, Bali. The method used in this research is the method of observation or direct observation done in the field. Data collection is done by direct observation in the field. The results showed that the turtle breeding site is located in an area that is less strategic because too far from the sea, so that the temperature and humidity cannot be stable. Water content is most an important factor in the growth of embryo and egg hatching. This will lead to the decrease of hatching percentage of turtle eggs.

  7. Author Details

    African Journals Online (AJOL)

    La tortue marine au Cameroun, genre Lepidochelys : nidification, biometrie de Lepidochelys olivacea (Eschscholtz, 1829) (Reptilia, Cheloniidae) dans la réserve de faune de Campo (Sud Cameroun) Abstract PDF · Vol 6, No 2 (2012) - Articles Monitoring the green turtle population Chelonia mydas (Linné, 1758) in the ...

  8. Overseas Environmental Baseline Guidance Document

    Science.gov (United States)

    2007-05-01

    tropical and temperate seas and oceans Sea turtle, olive ridley Lepidochelys olivacea Circumglobal in tropical and temperate seas Skink, Round Island...Scientific Name T&E Fauna Listed Overseas Sea turtle, Kemp’s ridley Lepidochelys kempii Tropical and temperate seas in Atlantic Basin, incl. Gulf of

  9. Author Details

    African Journals Online (AJOL)

    La tortue marine au Cameroun, genre Lepidochelys : nidification, biometrie de Lepidochelys olivacea (Eschscholtz, 1829) (Reptilia, Cheloniidae) dans la réserve de faune de Campo (Sud Cameroun) Abstract PDF · Vol 4, No 4 (2010) - Articles Impacts des eaux polluées sur la croissance, les teneurs en chlorophylles et ...

  10. Abstracts of Manuscripts Submitted in 1988 for Publication

    Science.gov (United States)

    1989-01-01

    ALLOPATRIC Lepidochelys olivacea ), or for juveniles and POPULATIONS OF THE subadults of the larger species, blood may be LEATHERBACK SEA TURTLE, obtained...Broadus III, Director population dynamics. For small species, such as GENETIC VARIABILITY IN TWO the ridley turtles ( Lepidochelys kemDi and SEASONALLY

  11. Characterization of the kidney transcriptome of the long-haired mouse Abrothrix hirta (Rodentia, Sigmodontinae and comparison with that of the olive mouse A. olivacea.

    Directory of Open Access Journals (Sweden)

    Lourdes Valdez

    Full Text Available To understand how small mammals cope with the challenge of water homeostasis is a matter of interest for ecologists and evolutionary biologists. Here we take a step towards the understanding of the transcriptomic functional response of kidney using as a model the long-haired mouse (Abrothrix hirta a species that distributes across Patagonian steppes and Austral temperate rainforests in Argentina and Chile. Specifically, we i characterize the renal transcriptome of A. hirta, and ii compare it with that-already available-of the co-generic and co-distributed A. olivacea. Renal mRNA transcripts from 16 specimens of A. hirta from natural populations were analyzed. Over 500 million Illumina paired-end reads were assembled de novo under two approaches, an individual assembly for each specimen, and a single in-silico normalized joint assembly including all reads from all specimens. The total number of annotated genes was similar with both strategies: an average of 14,956 in individual assemblies and 14,410 in the joint assembly. Overall, 15,463 distinct genes express in the kidney of A. hirta. Transcriptomes of A. hirta and A. olivacea were similar in terms of gene abundance and composition: 95.6% of the genes of A. hirta were also found in A. olivacea making their functional profiles also similar. However, differences in the transcriptome of these two species were observed in the set of highly expressed genes, in terms of private genes for each species and the functional profiles of highly expressed genes. As part of the novel transcriptome characterization, we provide distinct gene lists with their functional annotation that would constitute the basis for further research on these or any other species of the subfamily Sigmodontinae, which includes about 400 living species distributed from Tierra del Fuego to southern United States.

  12. Characterization of the kidney transcriptome of the long-haired mouse Abrothrix hirta (Rodentia, Sigmodontinae) and comparison with that of the olive mouse A. olivacea.

    Science.gov (United States)

    Valdez, Lourdes; Giorello, Facundo; Feijoo, Matías; Opazo, Juan C; Lessa, Enrique P; Naya, Daniel E; D'Elía, Guillermo

    2015-01-01

    To understand how small mammals cope with the challenge of water homeostasis is a matter of interest for ecologists and evolutionary biologists. Here we take a step towards the understanding of the transcriptomic functional response of kidney using as a model the long-haired mouse (Abrothrix hirta) a species that distributes across Patagonian steppes and Austral temperate rainforests in Argentina and Chile. Specifically, we i) characterize the renal transcriptome of A. hirta, and ii) compare it with that-already available-of the co-generic and co-distributed A. olivacea. Renal mRNA transcripts from 16 specimens of A. hirta from natural populations were analyzed. Over 500 million Illumina paired-end reads were assembled de novo under two approaches, an individual assembly for each specimen, and a single in-silico normalized joint assembly including all reads from all specimens. The total number of annotated genes was similar with both strategies: an average of 14,956 in individual assemblies and 14,410 in the joint assembly. Overall, 15,463 distinct genes express in the kidney of A. hirta. Transcriptomes of A. hirta and A. olivacea were similar in terms of gene abundance and composition: 95.6% of the genes of A. hirta were also found in A. olivacea making their functional profiles also similar. However, differences in the transcriptome of these two species were observed in the set of highly expressed genes, in terms of private genes for each species and the functional profiles of highly expressed genes. As part of the novel transcriptome characterization, we provide distinct gene lists with their functional annotation that would constitute the basis for further research on these or any other species of the subfamily Sigmodontinae, which includes about 400 living species distributed from Tierra del Fuego to southern United States.

  13. Environmental Compliance Assessment and Management Program

    Science.gov (United States)

    1994-04-01

    alba rothschildi REPTIES Pacific Green Sea Turtle - Chelonia mydas agassizi Olive (Pacific) Ridley Sea Turtle Lepidochelys olivacea PLANTS Haleakala...Eretmochelys imbricata bissa Pacific Leatherback Sea Turtle Dermochelys coriacea schlegelii Olive Ridley Sea Turtle jL~epidochelys olivacea MOLLUSK Oahu

  14. Mating behaviour of the orange mud crab, Scylla olivacea: The effect of sex ratio and stocking density on mating success

    Directory of Open Access Journals (Sweden)

    Khor Waiho

    2015-11-01

    Full Text Available Mud crabs from the genus Scylla have high commercial value and are considered as one of the highly sought luxury seafood items. Thorough understanding about their biology and mating behaviour is vital in providing important information for a sustainable exploitation and future incorporation into the aquaculture industry. The mating process of S. olivacea lasted 82.0 ± 10.8 h was divided into four phases: precopulation, molting, copulation, and postcopulation. Courtship displays and fighting were shown by mature males while they were courting females. Precopulatory position lasted for 55.2 ± 10.8 h before the pairs disengaged for the female to molt. The molting process was 4.6 ± 0.3 h. Copulation (mean duration was 6.6 ± 0.5 h occurred while the female’s exoskeleton was still soft. Postcopulatory guarding lasted for 13.6 ± 0.6 h. Separation of the mating pairs indicates the end of postcopulation phase. Mating success percentage was unaffected by sex ratio, but inversely affected by stocking density. Cumulative mortality increased with increasing stocking density and unequal sex ratios. Postcopulatory guarding duration was significantly shorter in treatment with 1 male:2 females ratio and treatment with the lowest stocking density (2 crabs m−2. We proposed rearing of mud crab broodstocks for mating purpose using sex ratio of 1 male:2 females and stocking density of 6 crabs m−2 to maximize output (successful mating pairs while maintaining low mortality percentage and shorter postcopulatory guarding duration.

  15. The complete chloroplast DNA sequence of the green alga Nephroselmis olivacea: insights into the architecture of ancestral chloroplast genomes.

    Science.gov (United States)

    Turmel, M; Otis, C; Lemieux, C

    1999-08-31

    Green plants seem to form two sister lineages: Chlorophyta, comprising the green algal classes Prasinophyceae, Ulvophyceae, Trebouxiophyceae, and Chlorophyceae, and Streptophyta, comprising the Charophyceae and land plants. We have determined the complete chloroplast DNA (cpDNA) sequence (200,799 bp) of Nephroselmis olivacea, a member of the class (Prasinophyceae) thought to include descendants of the earliest-diverging green algae. The 127 genes identified in this genome represent the largest gene repertoire among the green algal and land plant cpDNAs completely sequenced to date. Of the Nephroselmis genes, 2 (ycf81 and ftsI, a gene involved in peptidoglycan synthesis) have not been identified in any previously investigated cpDNA; 5 genes [ftsW, rnE, ycf62, rnpB, and trnS(cga)] have been found only in cpDNAs of nongreen algae; and 10 others (ndh genes) have been described only in land plant cpDNAs. Nephroselmis and land plant cpDNAs share the same quadripartite structure-which is characterized by the presence of a large rRNA-encoding inverted repeat and two unequal single-copy regions-and very similar sets of genes in corresponding genomic regions. Given that our phylogenetic analyses place Nephroselmis within the Chlorophyta, these structural characteristics were most likely present in the cpDNA of the common ancestor of chlorophytes and streptophytes. Comparative analyses of chloroplast genomes indicate that the typical quadripartite architecture and gene-partitioning pattern of land plant cpDNAs are ancient features that may have been derived from the genome of the cyanobacterial progenitor of chloroplasts. Our phylogenetic data also offer insight into the chlorophyte ancestor of euglenophyte chloroplasts.

  16. Sperm Viability Assessment over elapsing time maintained at 2 degrees C of orange mud crab, Scylla olivacea (Herbst, 1796).

    Science.gov (United States)

    Ikhwanuddin, M; Muhd-Farouk, H; Memon, A J; Wendy, W; Abol-Munafi, A B

    2014-09-01

    The aim of this study was to evaluate how long the fresh sperm maintained at 2 degrees C would be utilized for fishery management. The study was conducted every 2 h to assess the sperm viability of orange mud crab Scylla olivacea. Evaluations were conducted as 3 treatments; T1, T2 and T3. In T1, the live specimens were sacrificed; for T2, only spermatophores were extracted and for T3 spermatophore extraction followed by homogenization to create a sperm suspension. All samples were stored with ice in an insulated box was keep fresh longer at 2 degrees C. The time '0' referred the immediate collection of sperm after the specimen was sacrificed. Spermatophore viability was determined using the sperm suspension by eosin-nigrosin staining method. Sperm viability for the fresh sample at time zero was 97.36 ± 0.53%. Viability of the sperm significantly decreased in the 2nd h in all treatments, T1 was 44.66 ± 0.54 to 4.2 ± 0.22% at 16 and 18th h, T2 was 36.56 ± 0.5 to 2.69 ± 0.06% at the 12 and 14th h and T3 was 33.69 ± 1.26 to 6.4 ± 0.29% at 8 and 10th h. In comparison, T1 showed significantly higher than other treatments (p < 0.05). Extremely low viability percentages were recorded in T3. This study also proved that the time elapse had significant impact on the percentage of viable sperm count.

  17. Molecular cloning and differential expression pattern of two structural variants of the crustacean hyperglycemic hormone family from the mud crab Scylla olivacea.

    Science.gov (United States)

    Tsai, Kuo-Wei; Chang, Su-Jung; Wu, Hsin-Ju; Shih, Hsin-Yi; Chen, Chun-Hao; Lee, Chi-Ying

    2008-10-01

    Two full-length cDNA sequences encoding a crustacean hyperglycemic hormone (CHH) precursor were cloned from tissues of the mud crab Scylla olivacea. Sco-CHH (S. olivacea CHH) was cloned from eyestalk ganglia, whereas Sco-CHH-L (S. olivacea CHH-like peptide) was cloned from extra-eyestalk tissues (pericardial organ and thoracic ganglia). Each conceptually translated precursor is expected to be processed into a signal peptide, a CHH precursor-related peptide (CPRP), and a mature CHH or CHH-like peptide. The two precursors are identical in amino acid sequence through the 40th residue of the mature peptide, but different from each other substantially in the C-terminus. Both CHH variants contain the six highly conserved cysteine residues characteristic of the CHH family peptides, and share higher sequence identities with other brachyuran CHH sequences than with those of other taxonomic groups. As determined by reverse transcription-polymerase chain reaction (RT-PCR), the transcripts of Sco-CHH and Sco-CHH-L were present in eyestalk ganglia and several extra-eyestalk tissues (the thoracic ganglia, pericardial organ, brain, circumesophageal connectives, and gut). Sco-CHH was the predominant form in eyestalk ganglia, while Sco-CHH-L was the predominant form in several extra-eyestalk tissues. Neither transcript was expressed in the muscle, hepatopancreas, ovary, testis, heart, or gill. Antisera were raised against synthetic peptides corresponding to a stretch of sequence-specific to the C-terminus of Sco-CHH or Sco-CHH-L. Western blot analyses of tissues expressing Sco-CHH and Sco-CHH-L detected a Sco-CHH immunoreactive protein in the sinus gland, and a Sco-CHH-L immunoreactive protein in the pericardial organ. Immunohistochemical analyses of the eyestalk ganglia localized both Sco-CHH and Sco-CHH-L immunoreactivity to the sinus gland, and only Sco-CHH immunoreactivity to the X-organ somata; analyses of the pericardial organs also localized both Sco-CHH and Sco

  18. Aggressive displacement of Xylocopa nigrita carpenter bees from flowers of Lagenaria sphaerica (Cucurbitaceae by territorial male Eastern Olive Sunbirds (Cyanomitra olivacea in Tanzania

    Directory of Open Access Journals (Sweden)

    Jeff Ollerton

    2013-05-01

    Full Text Available Male Eastern Olive Sunbirds (Cyanomitra olivacea and Xylocopa nigrita carpenter bees in Tanzania both utilise the flowers of male plants of Lagenaria sphaerica (Cucurbitaceae as a source of nectar. The sunbirds set up territories defending this nectar resource. Observations of interactions between the sunbirds and the carpenter bees show that the bees are aggressively displaced from flowers when spotted by the birds. Only the bees can be considered as legitimate pollinators as the birds do not contact the anthers of the male flowers and were never seen visiting nectarless female flowers of Lagenaria sphaerica. Such territory defence may have implications for the frequency of movement and composition of pollen being transferred from male to female flowers which warrants further research.

  19. Inferring contemporary levels of gene flow and demographic history in a local population of the leaf beetle Gonioctena olivacea from mitochondrial DNA sequence variation.

    Science.gov (United States)

    Mardulyn, Patrick; Milinkovitch, Michel C

    2005-05-01

    We have studied mitochondrial DNA variation in a local population of the leaf beetle species Gonioctena olivacea, to check whether its apparent low dispersal behaviour affects its pattern of genetic variation at a small geographical scale. We have sampled 10 populations of G. olivacea within a rectangle of 5 x 2 km in the Belgian Ardennes, as well as five populations located approximately along a straight line of 30 km and separated by distances of 3-12 km. For each sampled individual (8-19 per population), a fragment of the mtDNA control region was polymerase chain reaction-amplified and sequenced. Sequence data were analysed to test whether significant genetic differentiation could be detected among populations separated by such relatively short distances. The reconstructed genealogy of the mitochondrial haplotypes was also used to investigate the demographic history of these populations. Computer simulations of the evolution of populations were conducted to assess the minimum amount of gene flow that is necessary to explain the observed pattern of variation in the samples. Results show that migration among populations included in the rectangle of 5 x 2 km is substantial, and probably involves the occurrence of dispersal flights. This appears difficult to reconcile with the results of a previous ecological field study that concluded that most of this species dispersal occurs by walking. While sufficient migration to homogenize genetic diversity occurs among populations separated by distances of a few hundred metres to a few kilometres, distances greater than 5 km results in contrast in strong differentiation among populations, suggesting that migration is drastically reduced on such distances. Finally, the results of coalescent simulations suggest that the star-like genealogy inferred from the mtDNA sequence data is fully compatible with a past demographic expansion. However, a metapopulation structure alone (without the need to invoke a population expansion

  20. Characterization of red pigment concentrating hormone (RPCH) in the female mud crab (Scylla olivacea) and the effect of 5-HT on its expression.

    Science.gov (United States)

    Kornthong, Napamanee; Chotwiwatthanakun, Charoonroj; Chansela, Piyachat; Tinikul, Yotsawan; Cummins, Scott F; Hanna, Peter J; Sobhon, Prasert

    2013-05-01

    Red pigment concentrating hormone (RPCH) is a member of the chromatophorotropic hormones and, in crustaceans, it is synthesized in the eyestalk. We have isolated a full-length cDNA for a RPCH preprohormone gene (Scyol-RPCH) from the eyestalks of female mud crabs, Scylla olivacea. The open reading frame consists of 642 nucleotides, and encodes a deduced 108 amino acid precursor protein, which includes a signal peptide, the RPCH (pQLNFSPGWamide), and an associated peptide. We show that the mud crab RPCH peptide exhibits 100% identity with 15 other decapods. Expression of Scyol-RPCH within adult mud crab takes place in the eyestalk, brain, and ventral nerve cord, comprising subesophageal ganglion, thoracic ganglion, and abdominal ganglion. In situ hybridization demonstrates specific expression within neuronal clusters 1, 2, 3, and 4 of the eyestalk X-organ, clusters 6, 8, 9, 10, and 17 of the brain, and in neuronal clusters of the ventral nerve cord. We found that administration of 5-HT up-regulates RPCH gene expression in the eyestalk, suggesting that RPCH may play a role as a downstream hormone of 5-HT. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Trypanosoma naviformis sp. nov. (Kinetoplastidae: Trypanosomatidae) from widespread African songbirds, the Olive sunbird (Cyanomitra olivacea) and Yellow-whiskered greenbul (Andropadus latirostris).

    Science.gov (United States)

    Sehgal, Ravinder N M; Iezhova, Tatjana A; Marzec, Timothy; Valkiūnas, Gediminas

    2015-10-29

    Trypanosoma naviformis n. sp. is described from the African olive sunbird Cyanomitra olivacea in Ghana based on the morphology of its hematozoic trypomastigotes and partial sequences of the small subunit ribosomal RNA gene. This parasite belongs to the group of small non-striated avian trypanosomes (< 30 µm in length in average) with the kinetoplast situated close to the posterior end of the body. Trypanosoma naviformis can be distinguished from other small avian trypanosomes due to its poorly visible flagellum, central position of its nucleus, and the symmetrically (in relation to the nucleus) narrowing of both ends of the hematozoic trypomastigotes, which are boat-like in shape. Illustrations of trypomastigotes of the new species are given, and SSU rDNA lineages associated with this parasite are documented. This parasite has been reported in Ghana and Cameroon and was also found in the yellow-whiskered greenbul, Andropadus latirostris in these countries. It appears to be widespread in its range given the distribution of these bird species in Africa.

  2. New host and distribution records for Aplectana hamatospicula (Ascaridida: Cosmocercidae) in Gastrophryne olivacea (Anura: Microhylidae) from the Great Plains U.S.A.

    Science.gov (United States)

    Vhora, M Suhail; Bolek, Matthew G

    2013-06-01

    Aplectana hamatospicula is a nematode that parasitizes the large intestine of anurans, and has been reported from bufonids, eleutherodactylids, hylids, microhylids, and ranids from North and Central America. Aplectana hamatospicula was first described, over 70 yr ago, from Hyla eximia and Bufo peltocephalus from Mexico and Cuba, respectively, and reported from Gastrophryne carolinensis from Florida. Since then there have been no reports of this nematode in North America north of Mexico. The life cycle of A. hamatospicula is not known, and there is limited information on Aplectana spp. from North America. During 2010-2011, we collected 351 anurans of 8 species from 4 locations in Stillwater, Payne County, Oklahoma, U.S.A., and examined them for the presence of Aplectana spp. Of the 8 species of anurans surveyed, A. hamatospicula infected only the Great Plains narrowmouth toad (Gastrophryne olivacea). The prevalence of A. hamatospicula was 85.7% (12/14) with a mean abundance of 28.4 + 24.0 and a mean intensity of 33.1 + 22.8 worms per infected toad. We provide new morphological measurements for male and female A. hamatospicula along with new locality records for this nematode in North America.

  3. Environmental Assessment for Employment of a Mobile Laser Evaluator System (LES-M) for the 20th Fighter Wing at Shaw Air Force Base, South Carolina

    Science.gov (United States)

    2004-05-01

    scarlet tanagers (Piranga olivacea ). The concentration of migrants occurs mainly along the coast, although several species of raptors such as...turtle Lepidochelys kempii* E Known -·-··· leatherback sea turtle Der.mochetvscoriacea• E , nown oggerhead sea turtle ,Caretta caretta T nown i...americana E Known Piping plover Charadrius melodus tr CH Known . ... _ Kemp’s ridley sea turtle Lepidoche /ys kempii* !- E Known -~ ... eatherback

  4. Characterization of sea turtles aggregations in Uruguay (Southwestern Atlantic Ocean): the ecology of the green turtle in temperate waters

    OpenAIRE

    Vélez Rubio, Gabriela Manuela

    2017-01-01

    Introducción Actualmente existen siete especies de tortugas marinas. Estas son la tortuga laúd o siete quillas (Dermochelys coriacea) como única especie representante de la familia Dermochelyidae, y las seis especies vivientes de la familia Cheloniidae: la tortuga carey (Eretmochelys imbricata), la tortuga lora (Lepidochelys kempii), la tortuga olivácea (Lepidochelys olivacea), la tortuga boba o cabezona (Caretta caretta), la tortuga verde (Chelonia mydas) y la tortuga aplanada (Natator d...

  5. Functional Assessment of Residues in the Amino- and Carboxyl-Termini of Crustacean Hyperglycemic Hormone (CHH) in the Mud Crab Scylla olivacea Using Point-Mutated Peptides.

    Science.gov (United States)

    Liu, Chun-Jing; Huang, Shiau-Shan; Toullec, Jean-Yves; Chang, Cheng-Yen; Chen, Yun-Ru; Huang, Wen-San; Lee, Chi-Ying

    2015-01-01

    To assess functional importance of the residues in the amino- and carboxyl-termini of crustacean hyperglycemic hormone in the mud crab Scylla olivacea (Sco-CHH), both wild-type and point-mutated CHH peptides were produced with an amidated C-terminal end. Spectral analyses of circular dichroism, chromatographic retention time, and mass spectrometric analysis of the recombinant peptides indicate that they were close in conformation to native CHH and were produced with the intended substitutions. The recombinant peptides were subsequently used for an in vivo hyperglycemic assay. Two mutants (R13A and I69A rSco-CHH) completely lacked hyperglycemic activity, with temporal profiles similar to that of vehicle control. Temporal profiles of hyperglycemic responses elicited by 4 mutants (I2A, F3A, D12A, and D60A Sco-CHH) were different from that elicited by wild-type Sco-CHH; I2A was unique in that it exhibited significantly higher hyperglycemic activity, whereas the remaining 3 mutants showed lower activity. Four mutants (D4A, Q51A, E54A, and V72A rSco-CHH) elicited hyperglycemic responses with temporal profiles similar to those evoked by wild-type Sco-CHH. In contrast, the glycine-extended version of V72A rSco-CHH (V72A rSco-CHH-Gly) completely lost hyperglycemic activity. By comparing our study with previous ones of ion-transport peptide (ITP) and molt-inhibiting hormone (MIH) using deleted or point-mutated mutants, detail discussion is made regarding functionally important residues that are shared by both CHH and ITP (members of Group I of the CHH family), and those that discriminate CHH from ITP, and Group-I from Group-II peptides. Conclusions summarized in the present study provide insights into understanding of how functional diversification occurred within a peptide family of multifunctional members.

  6. Functional Assessment of Residues in the Amino- and Carboxyl-Termini of Crustacean Hyperglycemic Hormone (CHH in the Mud Crab Scylla olivacea Using Point-Mutated Peptides.

    Directory of Open Access Journals (Sweden)

    Chun-Jing Liu

    Full Text Available To assess functional importance of the residues in the amino- and carboxyl-termini of crustacean hyperglycemic hormone in the mud crab Scylla olivacea (Sco-CHH, both wild-type and point-mutated CHH peptides were produced with an amidated C-terminal end. Spectral analyses of circular dichroism, chromatographic retention time, and mass spectrometric analysis of the recombinant peptides indicate that they were close in conformation to native CHH and were produced with the intended substitutions. The recombinant peptides were subsequently used for an in vivo hyperglycemic assay. Two mutants (R13A and I69A rSco-CHH completely lacked hyperglycemic activity, with temporal profiles similar to that of vehicle control. Temporal profiles of hyperglycemic responses elicited by 4 mutants (I2A, F3A, D12A, and D60A Sco-CHH were different from that elicited by wild-type Sco-CHH; I2A was unique in that it exhibited significantly higher hyperglycemic activity, whereas the remaining 3 mutants showed lower activity. Four mutants (D4A, Q51A, E54A, and V72A rSco-CHH elicited hyperglycemic responses with temporal profiles similar to those evoked by wild-type Sco-CHH. In contrast, the glycine-extended version of V72A rSco-CHH (V72A rSco-CHH-Gly completely lost hyperglycemic activity. By comparing our study with previous ones of ion-transport peptide (ITP and molt-inhibiting hormone (MIH using deleted or point-mutated mutants, detail discussion is made regarding functionally important residues that are shared by both CHH and ITP (members of Group I of the CHH family, and those that discriminate CHH from ITP, and Group-I from Group-II peptides. Conclusions summarized in the present study provide insights into understanding of how functional diversification occurred within a peptide family of multifunctional members.

  7. Environmental Assessment for Hypersonic Technology Vehicle 2 Flight Tests

    Science.gov (United States)

    2009-04-01

    turtle Caretta caretta T Olive ridley sea turtle Lepidochelys oliveacea T Leatherback sea turtle Dermochelys coriacea E Notes: MMPA = Protected...Turtles Green Sea Turtle Chelonia mydas T, RS Loggerhead Sea Turtle Caretta caretta T, RS Olive Ridley Sea Turtle Lapidochelys olivacea T, RS...Lapidochelys olivacea T, RS Leatherback Sea Turtle Dermochelys coriacea E, RS Hawksbill Sea Turtle Eretmochelys imbricata E, RS Fish Napoleon

  8. Final Environmental Assessment/Overseas Environmental Assessment Joint Strile Fighter System Development and Demonstration Developmental Test Program

    Science.gov (United States)

    2007-01-01

    turtle–E (Dermochelys coriacea) U U Y Y Green turtle–T/E (Chelonia mydas) Y Y Y Y Olive ridley turtle–T ( Lepidochelys olivacea ) U U U U Fish...Hawksbill sea turtle E A L L L Lepidochelys kempii Kemp’s Ridley sea turtle E L L L L Caretta caretta Loggerhead sea turtle T M M M M Source: DoN...coriacea E E Kemp’s Ridley Sea Turtle Lepidochelys kempii E E Loggerhead Sea Turtle 135 Caretta caretta T T Eastern Spiny Softshell Apalone s

  9. Structural and functional comparisons and production of recombinant crustacean hyperglycemic hormone (CHH) and CHH-like peptides from the mud crab Scylla olivacea.

    Science.gov (United States)

    Chang, Chih-Chun; Tsai, Kuo-Wei; Hsiao, Nai-Wan; Chang, Cheng-Yen; Lin, Chih-Lung; Watson, R Douglas; Lee, Chi-Ying

    2010-05-15

    Sco-CHH and Sco-CHH-L (CHH-like peptide), two structural variants of the crustacean hyperglycemic hormone family identified in the mud crab (Scylla olivacea), are presumably alternatively spliced gene products. In this study, Sco-CHH and Sco-CHH-L were isolated from the tissues using high performance liquid chromatography. Identity of the native peptides was confirmed using mass spectrometric (MS) analyses of purified materials and of trypsin-digested peptide fragments. Additionally, characterizations using circular dichroism (CD) spectrometry revealed that the 2 peptides have similar CD spectral profiles, showing they are composed mainly of alpha-helices, and are similarly thermo-stable with a melting temperature of 74-75 degrees C. Results of bioassays indicated that Sco-CHH exerted hyperglycemic and molt-inhibiting activity, whereas Sco-CHH-L did not. Further, recombinant Sco-CHH-Gly (rSco-CHH-Gly, a glycine extended Sco-CHH) and Sco-CHH-L (rSco-CHH-L) were produced using an Escherichia coli expression system, refolded, and purified. rSco-CHH-Gly was further alpha-amidated at the C-terminal end to produce rSco-CHH. MS analyses of enzyme-digested peptide fragments of rSco-CHH-Gly and rSco-CHH-L showed that the two peptides share a common disulfide bond pattern: C7-C43, C23-C39, and C26-C52. Circular dichroism analyses and hyperglycemic assay revealed that rSco-CHH and rSco-CHH-L resemble their native counterparts, in terms of CD spectral profiles, melting curve profiles, and biological activity. rSco-CHH-Gly has a lower alpha-helical content (32%) than rSco-CHH (47%), a structural deviation that may be responsible for the significant decrease in the biological activity of rSco-CHH-Gly. Finally, modeled structure of Sco-CHH and Sco-CHH-L indicated that they are similarly folded, each with an N-terminal tail region and 4 alpha-helices. Putative surface residues located in corresponding positions of Sco-CHH and Sco-CHH-L but with side chains of different properties

  10. Download this PDF file

    African Journals Online (AJOL)

    Atlantic hawksbill Eretmoche/ys imbricata. (Chelonidae) and the Atlantic leather back. Demochelys coriacea (Demochelydae). Other species include Atlantic logger head Caretta caretta, Atlantic green turtle Che/onia myo'as,. Atlantic ridley turtle Lepidochelys kempii and Olive ridley turtle L. Olivacea all of which belong to ...

  11. Studies on transplantation of marine turtle nests at Karachi coast (Sindh), Pakistan

    International Nuclear Information System (INIS)

    Firdous, F.

    2011-01-01

    Egg clutches of two species of marine turtles, namely Chelonia mydas and Lepidochelys olivacea, were collected during 1974 to 1997 and transplanted to the protected enclosures. The emerging hatching were released to the natural environment. The experiment helped to produce an average of 19495.5 hatch lings per year of green and 1174.5 per year of olive ridley turtles. (author)

  12. The Environmental Assessment and Management (TEAM) Guide: Mississippi Supplement

    Science.gov (United States)

    2010-03-01

    Yes Yes 3 Pelecanus occidentalis Brown Pelican Yes Yes 2 Picoides borealis Red-Cockaded Woodpecker Yes Yes 2 Piranga olivacea Scarlet Tanager Yes...Kingsnake Yes 3 Lampropeltis triangulum syspila Red Milk Snake Yes Yes 2 Lepidochelys kempii Kemp’s or Atlantic Ridley Yes Yes 1 Macrochelys

  13. Impact of protective shark nets on sea turtles in KwaZulu-Natal ...

    African Journals Online (AJOL)

    Few hawksbills Eretmochelys imbricata and olive ridleys Lepidochelys olivacea were caught in the shark nets. Fewer sea turtles are caught by shark nets than by longlines and because the nesting populations of loggerheads, green turtles and leatherbacks are either stable or increasing in the South-West Indian Ocean, ...

  14. Environmental Compliance Assessment System (ECAS) - Oregon Supplement

    Science.gov (United States)

    1994-04-01

    AMPHIBIANS and REPTILES Chelonia mydas Green sea turtle E Dermochelys coriacca Leatherback sea turtle E Caretta caretta Loggerhead sea turtle T Lepidochelys ... olivacea Pacific ridley sea turtle T I1 -7 Appendix 11-1 (continued) SCIENTIFIC NAME COMMON NAME STATUS FISH Gila bocolor ssp. Hutton spring tui chub

  15. Body temperature of the loggerhead sea turtle Caretta caretta and ...

    African Journals Online (AJOL)

    Lepidochelys olivacea L respectively, after emerging from water of 27,SoC to nest. (Mrosovsky &. Pritchard 1971). Smaller but significant temperature differentials have been reported for green and hawksbill turtles by Hirth (1962). Records of body temperatures of free-ranging animals are scarce; the only record being.

  16. Environmental Assessment for Conventional Strike Missile Demonstration

    Science.gov (United States)

    2010-08-01

    E Loggerhead sea turtle Caretta caretta T Olive ridley sea turtle Lepidochelys oliveacea T Leatherback sea turtle Dermochelys coriacea E Notes...Sea Turtle Lapidochelys olivacea T, RS Leatherback Sea Turtle Dermochelys coriacea E, RS Hawksbill Sea Turtle Eretmochelys imbricata E, RS Birds

  17. Final Environmental Assessment for Minuteman III Modification

    Science.gov (United States)

    2004-12-30

    imbricata E - Loggerhead sea turtle Caretta caretta T - Olive ridley sea turtle Lepidochelys oliveacea T - Leatherback sea turtle Dermochelys... olivacea T Leatherback Sea Turtle Dermochelys coriacea E Hawksbill Sea Turtle Eretmochelys imbricata E Mollusks Observed at Illeginni Island Top-Snail

  18. An Evaluation of Sea Turtle Populations and Survival Status on Vieques Island.

    Science.gov (United States)

    1982-06-22

    individual was seen and identified with certainty during I the 19S0-81 survey. 3 Neither species of Lepidochelys has ever been released from Vieques...though one individual of L. olivacea is known from Puerto Rico. 3 (Caldwell and Erdman 1969) I I II 3. STUDY PERSONNEL I Peter C.H. Pritchard, M.A

  19. 633-IJBCS-Article-Hyacinthe Angoni

    African Journals Online (AJOL)

    DR GATSING

    ), la tortue olivâtre (Lepidochelys olivacea), la tortue verte (Chelonia mydas), la tortue imbriquée (Eretmochelys imbricata). La tortue Chelonia mydas et. Eretmochelys imbricata, vivent autour des rochers colonisés par des algues et des.

  20. 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

  1. Report of Enodiotrema megachondrus (Looss, 1899 Looss, 1901 (Digenea: Plagiorchiidae in a green turtle Chelonia mydas Linnaeus, 1758 (Testudines, Cheloniidae from Brazil

    Directory of Open Access Journals (Sweden)

    Werneck M. R.

    2016-12-01

    Full Text Available This paper describes the occurrence of Enodiotrema megachondrus (Looss, 1899 Looss, 1901 in a juvenile green sea turtle (Chelonia mydas Linnaeus, 1758 found on the coast of Brazil. This parasite has been described in Caretta caretta from Egypt, France, the Mediterranean Sea, the Madeira Archipelago, the Adriatic Sea and the USA, in C. mydas from Egypt and the USA, in Eretmochelys imbricata from Cuba, in Lepidochelys olivacea from Mexico and Costa Rica and in Lepidochelys kempii from USA. This note represents the first report of E. megachondus in a green sea turtle in the South-West Atlantic Ocean.

  2. Environmental Impact Research Program. Life History and Environmental Requirements of Loggerhead Sea Turtles.

    Science.gov (United States)

    1986-01-01

    Lepidochelys kempii," Biol- .ogy and Conservation of Sea Turtles, K. A. Bjorndal, ed., Smithsonian Institu- tion...1977. "Kemp’s Ridley. Lepidochelys kempii (Garmaan 1880), Undoubtedly the Most Endangered Marine Turtle Today (with Notes on the Current . Status of...Lepidochetys olivacea )," Bulletin of the Maryland Herpetological Society, Vol 13, No. 3, pp 170-192. .% 44 ’.r.d 0 ? -,~’ yd’~ - .4. * *1 .4 4 .11 A -4.. .4 www ha .4. A h$i. *1 .4U I -1 ’I,. 4. p

  3. Plastic debris ingestion by sea turtle in Paraíba, Brazil.

    Science.gov (United States)

    Mascarenhas, Rita; Santos, Robson; Zeppelini, Douglas

    2004-08-01

    Coastal gill net entanglement and debris intake are important threats to the survival of sea turtles. Two sea turtles (Lepidochelys olivacea and Chelonia mydas) were found stranded along the coast of Paraíba. After necropsy, plastic debris were found in the stomach. The debris is described. This is the first record of this sort of problem for the Paraíba littoral.

  4. Sources of Vibrio mimicus contamination of turtle eggs.

    Science.gov (United States)

    Acuña, M T; Díaz, G; Bolaños, H; Barquero, C; Sánchez, O; Sánchez, L M; Mora, G; Chaves, A; Campos, E

    1999-01-01

    Vibrio mimicus contamination of sand increased significantly during the arrival of the olive ridley sea turtles (Lepidochelys olivacea) at Ostional anidation beach, Costa Rica. Statistical analysis supports that eggs are contaminated with V. mimicus by contact with the sand nest. V. mimicus was isolated from eggs of all nests tested, and ctxA+ strains were found in 31% of the nests, all of which were near the estuary.

  5. Patterns and inferred processes associated with sea turtle strandings in Paraíba State, Northeast Brazil

    OpenAIRE

    Poli, C.; Lopez, LCS.; Mesquita, DO; Saska, C.; Mascarenhas, R.

    2014-01-01

    This study analysed sea turtle strandings on the coast of Paraíba State, Northeastern Brazil, from August 2009 to July 2010. A total of 124 strandings were recorded in this period: green turtle Chelonia mydas (n = 106), hawksbill Eretmochelys imbricata (n = 15), olive ridley Lepidochelys olivacea (n = 2) and loggerhead Caretta caretta (n = 1). Of all turtles for which the Curved Carapace Length (CCL) was measured (n = 122), only 12 individuals (9.7%) were adults. Twenty individuals had synthe...

  6. 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 to ... more about: The latest news and events about electronic cigarettes on this FDA page Electronic cigarette basics on ...

  7. Electronic technology

    International Nuclear Information System (INIS)

    Kim, Jin Su

    2010-07-01

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

  8. 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.

  9. 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.

  10. Electron radiography

    Science.gov (United States)

    Merrill, Frank E.; Morris, Christopher

    2005-05-17

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

  11. Molecular Data for the Sea Turtle Population in Brazil

    Directory of Open Access Journals (Sweden)

    Sibelle Torres Vilaça

    2013-01-01

    Full Text Available We report here a dataset comprising nine nuclear markers for the Brazilian population of Cheloniidae turtles: hawksbills (Eretmochelys imbricata, loggerheads (Caretta caretta, olive ridleys (Lepidochelys olivacea, and green turtles (Chelonia mydas. Because hybridization is a common phenomenon between the four Cheloniidae species nesting on the Brazilian coast, we also report molecular markers for the hybrids E. imbricata × C. caretta, C. caretta × L. olivacea, and E. imbricata × L. olivacea and for one hybrid E. imbricata × C. mydas and one between three species C. mydas × E. imbricata × C. caretta. The data was used in previous studies concerning (1 the description of frequent hybrids C. caretta × E. imbricata in Brazil, (2 the report of introgression in some of these hybrids, and (3 population genetics. As a next step for the study of these hybrids and their evolution, genome-wide studies will be performed in the Brazilian population of E. imbricata, C. caretta, and their hybrids.

  12. Electron detector

    International Nuclear Information System (INIS)

    Hashimoto, H.; Mogami, A.

    1975-01-01

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

  13. Electron/electron acoustic instability

    International Nuclear Information System (INIS)

    Gary, S.P.

    1987-01-01

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

  14. 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)

  15. 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

  16. 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.

  17. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  18. Electronic Commerce

    OpenAIRE

    Slavko Đerić

    2016-01-01

    Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks...

  19. Electronic Publishing.

    Science.gov (United States)

    Lancaster, F. W.

    1989-01-01

    Describes various stages involved in the applications of electronic media to the publishing industry. Highlights include computer typesetting, or photocomposition; machine-readable databases; the distribution of publications in electronic form; computer conferencing and electronic mail; collaborative authorship; hypertext; hypermedia publications;…

  20. ELECTRONIC SIGNATURES

    African Journals Online (AJOL)

    10332324

    (a) facilitate ecommerce;2. (b) remove and prevent barriers to electronic communications in South Africa;3. (c) ensure that electronic transactions in the Republic conform to the highest international standards;4. (d) promote the development of electronic transactions services which are responsive to the needs of users and ...

  1. 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

  2. Sticker electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-09-08

    Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces. The stickers can be wrappable, placed on surfaces, glued on walls or mirrors or wood or stone, and have electronics (112, 122, 132) which may or may not be ultrathin. Packaging for the electronic sticker can use polymer on cellulose manufacturing and/or three dimensional (3-D) printing. The electronic stickers may provide lighting capability, sensing capability, and/or recharging capabilities.

  3. 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....

  4. The electron and the electronics

    International Nuclear Information System (INIS)

    Sanchez Balmaseda, M.

    1997-01-01

    The aim of this work is to present a brief report of those historical events that originated and contributed to the scientific area of Electronics. The main discovering and investigations in both Vacuum Electronics and Semiconductor Electronics are reviewed. (Author) 12 refs

  5. 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.

  6. Electron spectroscopy

    International Nuclear Information System (INIS)

    Hegde, M.S.

    1979-01-01

    An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

  7. Balaenophilus manatorum (Ortíz, Lalana and Torres, 1992) (Copepoda: Harpacticoida) from loggerhead sea turtles, Caretta caretta, from Japan and the western Mediterranean: amended description and geographical comparison.

    Science.gov (United States)

    Aznar, F Javier; Badillo, F Javier; Mateu, Paula; Raga, J Antonio

    2010-04-01

    The ectoparasitic harpacticoid copepod, Balaenophilus manatorum (Ortíz, Lalana and Torres, 1992) (syn. Balaenophilus umigamecolus Ogawa, Matsuzaki and Misaki, 1997), has been reported on 3 species of marine turtles from the Pacific and the Mediterranean and from the West Indian manatee off Cuba in the Caribbean. The 3 available descriptions of this species were made using light microscopy. In this paper, we provide an amended description of B. manatorum using scanning electronic microscopy (SEM) for specimens in the collection from which B. umigamecolus was originally described. This material was collected from 1 loggerhead sea turtle, Caretta caretta, from Japan. The use of SEM allowed us to add several new microcharacters to the original description but, more importantly, allowed us to correct a number of the traits originally described. Some of the corrections could affect the interpretation of putative homology and variability of characters among populations of B. manatorum. A SEM comparison of specimens of B. manatorum from loggerheads from Japan and the western Mediterranean suggested the existence of morphological stasis between these populations. However, there were apparent meristic differences with a recently published description of this species from olive ridleys, Lepidochelys olivacea, in Mexico. Although B. manatorum is currently considered as a single, widespread taxon, the possibility that it actually represents a species complex deserves further attention.

  8. 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

  9. 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.

  10. 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.

  11. Electronics Industry

    National Research Council Canada - National Science Library

    Bell, Robert; Carroll-Garrison, Martina; Donovan, Daniel; Fisher, John; Guemmer, Paul; Harms, Robert; Kelly, Timothy; Love, Mattie; McReynolds, James; Ward, Ralph

    2006-01-01

    .... Government action to preserve strategic access to semiconductor producers is clearly needed to ensure DoD electronic systems can be built without compromising sensitive technology, though every...

  12. Isolated electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ekstrom, Ph.; Winwland, D.

    1981-08-01

    The problem of electron g-factor measurement by means of an isolated electron is considered. The technique of the experiment performed at the Washington university is described. A single electron is enclosed in a homogeneous magnetic field which is superimposed by an electric field. The electric field configuration represents a Penning trap. The trap together with the enclosed electron forms an ''atom'' of macroscopic dimensions. The electron trajectory in the trap consists of three components. The electron quickly rotates over small loops (cyclotron motion), the centre of these loops slowly moves over a large circle (magistron motion). Meanwhile the electron oscillates back and forth along the trap axis. The electron motion in the atom field is quantized and the transitions between various types of motions correspond to definite radiation frequencies. At the anomal frequency the transition with spin flip is registered and the electron g-factor is measured. The value g=2.0023193044 is obtained with a probable error less than a unit of the last decimal digit.

  13. The electron

    International Nuclear Information System (INIS)

    Hestenes, David; Weingartshofer, Antonio

    1991-01-01

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

  14. Electronic marketplaces

    OpenAIRE

    TALAFOUSOVÁ, Jana

    2011-01-01

    This thesis describes the principles of electronic and Internet marketplaces. For analyzing the status of the use of electronic marketplaces and online polling was done with the actual marketplace and society, which is a member of the marketplace. Proposal that trade through the market is prepared for a particular company, which previously traded through the marketplace.

  15. 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.

  16. Power electronics

    Indian Academy of Sciences (India)

    Kishore Chatterjee

    reference material for power electronics engineers, students and academicians. We thank the editors of Sadhana for inviting us to guest-edit this special issue on power electronics. July 2017. KISHORE CHATTERJEE. Department of Electrical Engineering,. Indian Institute of Technology,. Bombay, Powai, Mumbai 400076, ...

  17. Electronic Commerce and Electronic Business

    Indian Academy of Sciences (India)

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

    This special issue is motivated by the recent upsurge of research activity in the areas of electronic commerce and electronic business both in India and all over the world. The current research activity is quite intensive in the use of mathematical tools such as cryptography, game theory, mechanism design, optimization, ...

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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....

  5. Electron Scattering

    International Nuclear Information System (INIS)

    Li, Xiaodong; Lee, Kyong Sei; Shaw, J.J.; Bahri, C.

    1990-01-01

    Electron scattering is one of the best probes available to us to probe the nucleus. It has revealed to us, with unprecedented accuracy, the charge and current distributions of nuclei. It has provided us with positive evidence for meson exchange currents. It was used to 'discover' the quark and it revealed to us that nucleons may be modified in the nuclear environment (EMC Effect). In short, electron scattering has revolutionized the study of nuclear physics. Several recent developments will insure that electron beams which will soon become availabe at CEBAF, Bates and elsewhere will make high-precision coincidence experiments possible. As the technology is becoming available, we are just beginning to exploit polarization degrees of freedom in our experiments. In this paper, we will introduce the formalism of electron scattering, review what we have learned in the past and look ahead toward the future

  6. 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....

  7. Paper electronics.

    Science.gov (United States)

    Tobjörk, Daniel; Österbacka, Ronald

    2011-05-03

    Paper is ubiquitous in everyday life and a truly low-cost substrate. The use of paper substrates could be extended even further, if electronic applications would be applied next to or below the printed graphics. However, applying electronics on paper is challenging. The paper surface is not only very rough compared to plastics, but is also porous. While this is detrimental for most electronic devices manufactured directly onto paper substrates, there are also approaches that are compatible with the rough and absorptive paper surface. In this review, recent advances and possibilities of these approaches are evaluated and the limitations of paper electronics are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 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

  9. Electron Emitters

    National Research Council Canada - National Science Library

    Tzeng, Yonhua

    2002-01-01

    When two carbon-nanotube coated electrodes are placed at a small distance from each other, electron emission from carbon nanotubes allows a DC or AC electrical current to flow between these two electrodes...

  10. 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...

  11. Electronic spectroscopies

    OpenAIRE

    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 directly chemical since the outer shell electrons of the TMI are probed and provide information about the oxidation state and coordination environment of TMI on surfaces. Furthermore, the DRS technique ca...

  12. Electronic commerce

    OpenAIRE

    Zvolánková, Pavla

    2010-01-01

    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.

  13. Spin Electronics

    Science.gov (United States)

    2003-08-01

    applications, a ferromagnetic metal may be used as a source of spin-polarized electronics to be injected into a semiconductor, a superconductor or a...physical phenomena in II-VI and III-V semiconductors. In II-VI systems, the Mn2+ ions act to boost the electron spin precession up to terahertz ...conductors, proximity effect between ferromagnets and superconductors , and the effects of spin injection on the physical properties of the

  14. 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...

  15. 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.

  16. 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

  17. 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...

  18. 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...

  19. Electronic Commerce

    Indian Academy of Sciences (India)

    2000-11-30

    Nov 30, 2000 ... applications of internet are exchange of electronic mail, ex- change of files (text as well as multimedia), storing information in a form which allows other computers connected to the internet to access it and remote logging into a computer and using it to run programs. For two computers in different locations to.

  20. Electronic Commerce

    Indian Academy of Sciences (India)

    Electronic commerce usually uses a public switched telephone network (PSTN) and is often between entities which are not known to one another. Ensuring security of communication between the entities participating in e-commerce is hence an important requirement. Apart from ensuring the security of messages on the ...

  1. Nuclear electronics

    International Nuclear Information System (INIS)

    Friese, T.

    1981-09-01

    A short survey is given on nuclear radiation detectors and nuclear electronics. It is written for newcomers and those, who are not very familiar with this technique. Some additional information is given on typical failures in nuclear measurement systems. (orig.) [de

  2. Power electronics

    Indian Academy of Sciences (India)

    Kishore Chatterjee

    Power electronics plays an important role in the processing, conditioning and utilization of electric power. From ubiquitous ... An induction motor drive based on a modular multilevel converter (MMC) is presented ... dynamic voltage restorer and the control of an induction motor drive having an active front end converter.

  3. 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…

  4. Electronics department

    International Nuclear Information System (INIS)

    1979-01-01

    This report summarizes the activities in 1978 of some of the groups within the Electronics Department. The work covered includes plant protection and operator studies, reliability techniques, application of nuclear techniques to mineral exploration, applied laser physics, computing and, lastly, research instrumentation. (author)

  5. Electronic Commerce

    Indian Academy of Sciences (India)

    nance, Vol.6, No.2, 6-13, 2001. SERIES I ARTICLE. Electronic Commerce. 5. Cash Transactions. V Rajaraman. In this article we will discuss payment by cash for e-com- merce transactions and micro payments for services re- ceived via the internet. Introduction. In the previous part, we discussed payment by credit cards and.

  6. Cryogenic electronics

    Energy Technology Data Exchange (ETDEWEB)

    Fourches, N.; Abbon, P.; Delagnes, E.; Le Meur, L.P.

    1995-04-01

    This study presents the cryogenic electronics, which is used in high energy physics with appropriate device. It discuss their ability to hardening against ionization radiation and neutrons. Some partial results on the operation of microelectronics devices at cryogenic temperature are given. (TEC). 33 refs., 13 figs.

  7. Electronic Commerce

    Indian Academy of Sciences (India)

    2000-11-30

    Nov 30, 2000 ... Electronic Commerce. 2. E-Commerce System Architecture. V Rajaraman is with the. J awaharlal Nehru Centre for Advanced Scientific. Research and the Indian. Institute of Science,. Bangalore. Several generations of scientists and engineers in India have learnt computer science using his lucidly.

  8. Electronic Commerce

    Indian Academy of Sciences (India)

    In the first part of this series we stated that in business to business e-commerce, electronic documents are exchanged be- tween business partners by using either a private network or a public switched network. We also stated that in order to inter- pret them correctly we need a standard notation which is agreed to by both ...

  9. 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.

  10. 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...... transistors (Part 2). The synthetic protocols rely on stepwise Sonogashira coupling reactions. Conductivity studies on various OPE-based molecular wires reveal that mere OPE compounds have a higher electrical resistance compared to the cruciform based wires (up to 9 times higher). The most spectacular result...

  11. A molecular phylogeny for marine turtles: trait mapping, rate assessment, and conservation relevance.

    Science.gov (United States)

    Bowen, B W; Nelson, W S; Avise, J C

    1993-06-15

    Nucleotide sequences from the cytochrome b gene of mitochondrial DNA were employed to resolve phylogenetic controversies and to assess molecular evolutionary rates in marine turtles (Chelonioidea). Findings of special relevance to conservation biology include discovery of a distant relationship between Natator and other cheloniid species, the paraphyly of Chelonia mydas with respect to Chelonia agassizi, and genetic distinctiveness of Lepidochelys kempi from Lepidochelys olivacea. A longstanding debate in evolutionary ecology was resolved by phylogenetic mapping of dietary habits, which indicates that the spongivore Eretmochelys imbricata evolved from a carnivorous rather than a herbivorous ancestor. Sequence divergences at intergeneric and interfamilial levels, when assessed against fossil-based separation times, support previous suggestions (from microevolutionary comparisons) that mitochondrial DNA in marine turtles evolves much more slowly than under the "conventional" vertebrate clock. This slow pace of nucleotide replacement is consistent with recent hypotheses linking substitution rate to generation length and metabolic pace.

  12. Automotive electronics

    Energy Technology Data Exchange (ETDEWEB)

    Basshuysen, R. van [ed.; Baun, R. [comp.

    2000-10-01

    Electronic equipment is indispensable in modern motor cars for active and passive safety, exhaust and consumption monitoring or comfort. Electric and electronic systems today account for nearly 20 percent of the production cost of a normal passenger car, with an upward trend. Infotainment equipment is a growing market, which gets center stage in this issue. Further subjects discussed are current electronic and mechatronic applications as well as new developments in data transmission, development tools and constructional elements. [German] Ohne Elektronik sind moderne Automobile nicht mehr vorstellbar. Ob aktive oder passive Sicherheit, Abgas, Verbrauch oder Komfort - der Fortschritt im Autombil ist eng verknuepft mit der Einfuehrung neuer elektronischer Systeme und Komponenten. Obwohl meist nicht sehr auffaellig in einer Black-box verpackt, liegen die anteiligen Herstellungskosten fuer die Elektrik und Elektronik bei einem Mittelklassefahrzeug schon bei knapp 20 Prozent. Tendenz: Weiter steigend. Waehrend die Segnungen von ABS, ESP oder Motormanagement fuer den Kunden unsichtbar bleiben, tritt die Elektronik mit den Infotainment-Systemen ins Rampenlicht. Hochwertige Audio-Anlagen im Doppel-DIN-Format und grosse Farbbildschirme sitzen an prominenter Stelle im Armaturenbrett. Elektronische Systeme werden damit fuer den Kunden sichtbar, greifbar und erlebbar. Doch je mehr Funktionen integriert werden, desto wichtiger wird eine einfache Bedienung, die den Fahrer moeglichst wenig vom Verkehrsgeschehen ablenkt. Das ist leider keine Selbstverstaendlichkeit: Eine klare, einfache Bedienung wurde in der Vergangenheit schon bei so manchem simplen Cassetten-Radio schmerzlich vermisst. Infotainment im Automobil ist ein Wachstumsmarkt - und das Schwerpunkt-Thema der vorliegenden zweiten Ausgabe von 'Automotive Electronics'. Darueber hinaus beschaeftigt sich auch diese Ausgabe mit aktuellen Elektronik- und Mechatronik-Anwendungen und berichtet ueber neue Entwicklungen

  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. 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.

  15. Evolutionary distinctiveness of the endangered Kemp's ridley sea turtle.

    Science.gov (United States)

    Bowen, B W; Meylan, A B; Avise, J C

    1991-08-22

    The endangered Kemp's ridley sea turtle (Lepidochelys kempi) nests almost exclusively at a single locality in the western Gulf of Mexico, whereas the olive ridley (L. olivacea) nests globally in warm oceans. Morphological similarities between kempi and olivacea, and a geographical distribution that "...makes no sense at all under modern conditions of climate and geography", raise questions about the degree of evolutionary divergence between these taxa. Analysis of mitochondrial (mt) DNA restriction sites shows that Kemp's ridley is distinct from the olive ridley in matriarchal phylogeny, and that the two are sister taxa with respect to other marine turtles. Separation of olive and the Kemp's ridley lineages may date to formation of the Isthmus of Panama, whereas the global spread of the olive ridley lineage occurred recently. In contrast to recent examples in which molecular genetic assessments challenged systematic assignments underlying conservation programmes, our mtDNA data corroborate the taxonomy of an endangered form.

  16. Crucero de evaluación del recurso merluza y otros dermesales BIC José Olaya Balandra 9806-07 de Puerto Pizarro a Huarmey

    OpenAIRE

    Zeballos Flor, Jorge; Samamé, Manuel; Romero, Miguel

    1998-01-01

    Presenta la composición especiólogica por lance de pesca realizado durante el Crucero BIC José Olaya Balandra 9806-07, del 27 de junio al 13 de julio de 1998. El análisis se realizó identificando los grupos taxonómicos y los pesos por especies. En total se registraron 126 especies: 96 peces, 19 crustáceos, 3 moluscos, 6 equinodermos, un cnidario y una "tortuga loro" Lepidochelys olivacea como pesca accidental. La captura total en el área estudiada fue de 24.192,86 kg, de los cuales 24.0...

  17. [Identification of turtle shell, tortoise plastron and their counterfeit products].

    Science.gov (United States)

    Wang, Z Z; Lin, J M; Ye, G M; Quan, S C; Hu, J H

    2000-05-01

    To identify the commercial Chinese medicines turtle shell and tortoise plastron. Morphological identification and differential thermal analysis (DTA). 2 kinds of counterfeit turtle shell and 3 kinds of counterfeit tortoise plastron were found, and their morphological and DTA identification features were proposed. Sea turtle shells presently on the market are sham commodities of turtle shell, which derive from Lissemys punctata and Pelochelys bibroni indigenous to south Asia, while plastrons of Ocadia sinensis, Chelonia mydas and Lepidochelys olivacea are counterfeit products of tortoise plastron. Turtle shells, tortoise plastrons and their counterfeit products may be exactly distinguished by morphological and DTA features.

  18. trans-6-Hexadecenoic acid in the Atlantic leatherbackDermochelys coriacea coriacea L. and other marine turtles.

    Science.gov (United States)

    Hooper, S N; Ackman, R G

    1970-03-01

    Depot fat from the Atlantic leatherback turtle (Dermochelys coriacea coriacea L.) was shown to contain ≈3% oftrans-6-hexadecenoic acid. Structural details were elucidated through comparative aspects of isolation techniques, NMR, IR, hydrogenation, oxidative fission, etc., and confirmed by similarity of properties with those of a sample of fatty acid of this structure isolated from the seed oil ofPicramnia sellowii. One additional leather-back turtle oil sample, and depot fat from two other marine turtles, the loggerhead (Caretta caretta caretta) and ridley (Lepidochelys olivacea kempi) contained this acid, that from the ridley in a lower proportion. No corresponding C18 acid was detected in the leatherback oil.

  19. Detectors - Electronics

    International Nuclear Information System (INIS)

    Bregeault, J.; Gabriel, J.L.; Hierle, G.; Lebotlan, P.; Leconte, A.; Lelandais, J.; Mosrin, P.; Munsch, P.; Saur, H.; Tillier, J.

    1998-01-01

    The reports presents the main results obtained in the fields of radiation detectors and associated electronics. In the domain of X-ray gas detectors for the keV range efforts were undertaken to rise the detector efficiency. Multiple gap parallel plate chambers of different types as well as different types of X → e - converters were tested to improve the efficiency (values of 2.4% at 60 KeV were reached). In the field of scintillators a study of new crystals has been carried out (among which Lutetium orthosilicate). CdTe diode strips for obtaining X-ray imaging were studied. The complete study of a linear array of 8 CdTe pixels has been performed and certified. The results are encouraging and point to this method as a satisfying solution. Also, a large dimension programmable chamber was used to study the influence of temperature on the inorganic scintillators in an interval from -40 deg. C to +150 deg. C. Temperature effects on other detectors and electronic circuits were also investigated. In the report mentioned is also the work carried out for the realization of the DEMON neutron multidetector. For neutron halo experiments different large area Si detectors associated with solid and gas position detectors were realized. In the frame of a contract with COGEMA a systematic study of Li doped glasses was undertaken aiming at replacing with a neutron probe the 3 He counters presently utilized in pollution monitoring. An industrial prototype has been realised. Other studies were related to integrated analog chains, materials for Cherenkov detectors, scintillation probes for experiments on fundamental processes, gas position sensitive detectors, etc. In the field of associated electronics there are mentioned the works related to the multidetector INDRA, data acquisition, software gamma spectrometry, automatic gas pressure regulation in detectors, etc

  20. 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

  1. Nuclear electronics

    International Nuclear Information System (INIS)

    Lucero B, E.

    1989-01-01

    The rapid technical development of Colombia over the past years, resulted among others, a considerable increase in the number of measuring instrumentation and testing laboratories, scientific research and metrology centers, in industry, agriculture, public health, education on the nuclear field, etc. IAN is a well organized institution with qualified management, trained staff and reasonably equipped laboratories to carry out tasks as: Metrology, standardization, quality control and maintenance and repair of nuclear instruments. The government of Colombia has adopted a policy to establish and operate through the country maintenance and repair facilities for nuclear instrumentation. This policy is reflected in the organization of electronic laboratories in Bogota-IAN

  2. 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

  3. 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

  4. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    The global electrical energy consumption is still rising and there is an urgent demand to increase the power capacity. It is expected that the power capacity has to be doubled within 20 years. The production, distribution and use of energy should be as efficient as possible and incentives to save...... 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...

  5. 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.

  6. 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

  7. Scanning transmission electron microscope

    NARCIS (Netherlands)

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the

  8. 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.

  9. Electron Beam Generation in Tevatron Electron Lenses

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  10. Electron beam generation in Tevatron electron lenses

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  11. Mobile electrons in electron-attaching liquids

    International Nuclear Information System (INIS)

    Nyikos, L.

    1981-01-01

    Based on recent observations of mobile electrons in electron-attaching liquids some ideas are presented concerning the nature of the fas carrier. To explain the observed phenomena quantum chemical calculations and modified percolation theory are applied. (author)

  12. 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.

  13. Electronics for LHC Experiments

    International Nuclear Information System (INIS)

    2004-01-01

    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

  14. Electronic Design Automation Using Object Oriented Electronics

    OpenAIRE

    Walid M. Aly; Mohamed S. Abuelnasr

    2010-01-01

    Problem statement: Electronic design automation is the usage of computer technology and software tools for designing integrated electronic system and creating electrical schematics. Approach: An approach is presented for modeling of various electronic and electric devices using object oriented design, aiming on building a library of devices (classes) which can be used for electronic design automation. Results: The presented library was implemented using Java programming language to form an El...

  15. 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...

  16. Introduction to Electronics course

    CERN Multimedia

    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...

  17. Introduction to electronics

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    Electronics in HEP experiments: specificities and evolution The Art of Electronics: is there something beyond Ohm's law? Basic building blocks of Analog electronics: quickly understanding a schematic Charge preamps, current preamps and future preamps, shaping and the rest Electronics noise: fundamental and practical Evolution of technology: ASICs, FPGAs...

  18. Seeing with Electrons

    Indian Academy of Sciences (India)

    Seeing with Electrons. A K Raychaudhuri. In this article we briefly review the application of electrons in the field of microscopy. Two types of microscopes are discussed, the electron microscope and the tunneling microscope. It is emphasized that in both the applications the electron behaves as a quantum mechanical object.

  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. In Situ Transmission Electron Microscopy for Electronics

    OpenAIRE

    Arita, Masashi; Hamada, Kouichi; Takahashi, Yasuo; Sueoka, Kazuhisa; Shibayama, Tamaki

    2015-01-01

    Electronic devices are strongly influenced by their microstructures. In situ transmission electron microscopy (in situ TEM) with capability to measure electrical properties is an effective method to dynamically correlate electric properties with microstructures. We have developed tools and in situ TEM experimental procedures for measuring electronic devices, including TEM sample holders and sample preparation methods. The method was used to study metallic nanowire by electromigration, magn...

  1. 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.

  2. 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

  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. 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.

  6. Energy electron analyzers raster electron microscope

    International Nuclear Information System (INIS)

    Dremova, N.N.; Raj, Eh.I.; Robinson, V.N.

    1995-01-01

    Spectrometers of back-scattered and secondary electrons used in a raster electron microscope designed to study multilayer structures and potential relief at the solid-state body surface, are described. Their possible applications are demonstrated using microelectronics devices as an example

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Electron scattering from pyrimidine

    International Nuclear Information System (INIS)

    Colmenares, Rafael; Fuss, Martina C; García, Gustavo; Oller, Juan C; Muñoz, Antonio; Blanco, Francisco; Almeida, Diogo; Limão-Vieira, Paulo

    2014-01-01

    Electron scattering from pyrimidine (C 4 H 4 N 2 ) was investigated over a wide range of energies. Following different experimental and theoretical approaches, total, elastic and ionization cross sections as well as electron energy loss distributions were obtained.

  12. ELSA electron stretcher devices

    International Nuclear Information System (INIS)

    1979-10-01

    The use of an electron stretcher ring at the Bonn electron synchrotron is discussed. The construction of the proposed ring is described, and the costs are estimated. Possible experiments using this ring are discussed. (HSI)

  13. Chapter 9: Electronics

    International Nuclear Information System (INIS)

    Grupen, Claus; Shwartz, Boris A.

    2006-01-01

    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

  14. Electron Paramagnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    IAS Admin

    ARTICLE. Electron Paramagnetic Resonance Spectroscopy. Biological Applications. B G Hegde. Recently, electron paramagnetic resonance (EPR) spectros- copy has emerged as a powerful tool to study the structure and dynamics of biological macromolecules such as proteins, protein aggregates ... research interests are.

  15. Electronic Health Records

    Science.gov (United States)

    ... Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español Electronic Health Records KidsHealth / For Teens / Electronic Health Records ...

  16. Electron microscopy for Engineers

    International Nuclear Information System (INIS)

    Jones, I P

    2009-01-01

    This paper reviews the application of (mainly) Transmission Electron Microscopy (TEM) in an engineering context. The first two sections are TEM and chemical in nature; the final three sections are more general and include aspects of Scanning Electron Microscopy (SEM).

  17. 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.

  18. 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.

  19. Electronic Science Seminar

    Directory of Open Access Journals (Sweden)

    Geidarov P.Sh.

    2015-09-01

    Full Text Available The structure of electronic scientific seminar, which provides a high level of quality of the objectivity in the evaluation of scientific papers, including dissertations, is described. Conditions for the implementation of electronic scientific seminar are also considered.

  20. Paleoclassical electron heat transport

    International Nuclear Information System (INIS)

    Callen, J.D.

    2005-01-01

    Radial electron heat transport in low collisionality, magnetically-confined toroidal plasmas is shown to result from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature equilibrates along magnetic field lines a long length L, which is the minimum of the electron collision length and a maximum effective half length of helical field lines. Thus, the diffusing field lines induce a radial electron heat diffusivity M ≅ L/(πR 0q ) ∼ 10 >> 1 times the magnetic field diffusivity η/μ 0 ≅ ν e (c/ω p ) 2 . The paleoclassical electron heat flux model provides interpretations for many features of 'anomalous' electron heat transport: magnitude and radial profile of electron heat diffusivity (in tokamaks, STs, and RFPs), Alcator scaling in high density plasmas, transport barriers around low order rational surfaces and near a separatrix, and a natural heat pinch (or minimum temperature gradient) heat flux form. (author)

  1. 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.

  2. Joint Services Electronics Program.

    Science.gov (United States)

    1983-09-30

    Compound Semiconductors." 4 ......... I-*. Univesity of California. Berkeley Electronics Research Laboratory Joint Services Electronics Program August 15...reduction techniques [SCH-66,MCG- 73,HAM-75], for essentially i educing the proportionality constant. A significant portion of the probabilistic literature

  3. 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.)

  4. 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

  5. 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

  6. Electron-attachment processes

    International Nuclear Information System (INIS)

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

    1982-01-01

    Topics covered include: (1) modes of production of negative ions, (2) techniques for the study of electron attachment processes, (3) dissociative electron attachment to ground-state molecules, (4) dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), (5) molecular parent negative ions, and (6) negative ions formed by ion-pair processes and by collisions of molecules with ground state and Rydberg atoms

  7. Electron Cyclotron Resonances in Electron Cloud Dynamics

    International Nuclear Information System (INIS)

    Celata, Christine; Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

    2008-01-01

    We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code 'POSINST' was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ∼(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed

  8. 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.

  9. Electron Induction Linacs

    Science.gov (United States)

    Caporaso, George J.; Chen, Yu-Jiuan

    Electron induction linacs have been used for over four decades for a variety of applications. As discussed in Chap. 8, these include basic studies in magnetically confined fusion, transport of intense electron beams in various gases, the generation of electromagnetic radiation from free electron lasers, radiation processing of materials and food, and flash X-ray radiography sources.

  10. Electronic recordkeeping: An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Deken, J.M.

    2000-01-19

    This paper begins with a brief overview of records and archival management before the advent of the electronic era; then describe the ways in which the definitions and constructs of archives and records management have been altered in the electronic environment; and outlines the various approaches to the challenges of electronic recordkeeping that are currently being investigated and applied.

  11. 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.

  12. 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

  13. 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. 

  14. 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.

  15. Nuclear markers reveal a complex introgression pattern among marine turtle species on the Brazilian coast.

    Science.gov (United States)

    Vilaça, Sibelle T; Vargas, Sarah M; Lara-Ruiz, Paula; Molfetti, Érica; Reis, Estéfane C; Lôbo-Hajdu, Gisele; Soares, Luciano S; Santos, Fabrício R

    2012-09-01

    Surprisingly, a high frequency of interspecific sea turtle hybrids has been previously recorded in a nesting site along a short stretch of the Brazilian coast. Mitochondrial DNA data indicated that as much as 43% of the females identified as Eretmochelys imbricata are hybrids in this area (Bahia State of Brazil). It is a remarkable find, because most of the nesting sites surveyed worldwide, including some in northern Brazil, presents no hybrids, and rare Caribbean sites present no more than 2% of hybrids. Thus, a detailed understanding of the hybridization process is needed to evaluate natural or anthropogenic causes of this regional phenomenon in Brazil, which could be an important factor affecting the conservation of this population. We analysed a set of 12 nuclear markers to investigate the pattern of hybridization involving three species of sea turtles: hawksbill (E. imbricata), loggerhead (Caretta caretta) and olive ridley (Lepidochelys olivacea). Our data indicate that most of the individuals in the crossings L. olivacea × E. imbricata and L. olivacea × C. caretta are F1 hybrids, whereas C. caretta × E. imbricata crossings present F1 and backcrosses with both parental species. In addition, the C. caretta × E. imbricata hybridization seems to be gender and species biased, and we also found one individual with evidence of multispecies hybridization among C. caretta × E. imbricata × Chelonia mydas. The overall results also indicate that hybridization in this area is a recent phenomenon, spanning at least two generations or ~40 years. © 2012 Blackwell Publishing Ltd.

  16. 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

  17. High brightness electron accelerator

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity. 5 figs

  18. Electron reconstruction in CMS

    CERN Document Server

    Baffioni, Stephanie; Ferri, Federico; Futyan, David; Meridiani, Paolo; Puljak, Ivica; Rovelli, Chiara; Salerno, Roberto; Sirois, Yves

    2006-01-01

    The reconstruction of the energy and momentum of isolated electrons in CMS combining tracking and electromagnetic calorimetry information is described. The emphasis is put on primary electrons with transverse momentum below 50 GeV/c. The energy deposited in the electromagnetic calorimeter is measured in superclusters which collect bremsstrahlung photons emitted along the electron trajectory in the tracker volume. The electron tracks are built from seeds in the pixel detector found via a cluster-driven pixel hit matching algorithm, followed by a reconstruction of trajectories in the silicon strip tracker with a Gaussian Sum Filter. Electrons are classified using observables sensitive to the pattern of bremsstrahlung emission and electromagnetic showering in the tracker material. Energy scale corrections depending on the electron class are applied to the supercluster and estimates of associated errors are obtained. The electron energy is deduced from a weighted combination of the corrected supercluster energy a...

  19. 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. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Seeing with electrons

    International Nuclear Information System (INIS)

    Nellist, P.

    2006-01-01

    Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

  1. 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...

  2. 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 ...

  3. 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.

  4. ELECTRON COOLING OF RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    BEN-ZVI, I.; LITVINENKO, V.; BARTON, D.; ET AL.

    2005-05-16

    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.

  5. 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.

  6. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Electronic Publishing or Electronic Information Handling?

    Science.gov (United States)

    Heck, A.

    The current dramatic evolution in information technology is bringing major modifications in the way scientists communicate. The concept of 'electronic publishing' is too restrictive and has often different, sometimes conflicting, interpretations. It is thus giving way to the broader notion of 'electronic information handling' encompassing the diverse types of information, the different media, as well as the various communication methodologies and technologies. New problems and challenges result also from this new information culture, especially on legal, ethical, and educational grounds. The procedures for validating 'published material' and for evaluating scientific activities will have to be adjusted too. 'Fluid' information is becoming a common concept. Electronic publishing cannot be conceived without link to knowledge bases nor without intelligent information retrieval tools.

  8. 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.

  9. Interoperability for electronic ID

    OpenAIRE

    Zygadlo, Zuzanna

    2009-01-01

    Electronic Business, including eBanking, eCommerce and eGovernmental services, is today based on a large variety of security solutions, comprising electronic IDs provided by a broad community of Public Key Infrastructure (PKI) vendors. Significant differences in implementations of those solutions introduce a problem of lack of interoperability in electronic business, which have not yet been resolved by standardization and interoperability initiatives based on existing PKI trust models. It i...

  10. 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

  11. 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

  12. 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

  13. Electron microscopy of surfaces

    International Nuclear Information System (INIS)

    Venables, J.A.

    1981-01-01

    Electron beam techniques used to study clean surfaces and surface processes on a microscopic scale are reviewed. Recent experimental examples and possible future developments are discussed. Special emphasis is given to (i) transmission diffraction and microscopy techniques, including atomic imaging; (ii) Auger microscopy on bulk and thin film samples; (iii) secondary electron microscopy, especially low energy secondaries for work-function imaging and photoelectron imaging; and (iv) reflection electron microscopy and diffraction. (orig.)

  14. 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.

  15. Electron microscopy and diffraction

    International Nuclear Information System (INIS)

    Gjoennes, J.; Olsen, A.

    1986-01-01

    This report is a description of research activities and plans at the electron microscopy laboratorium, Physics Department, University of Oslo. Since the first electron microscope was installed in 1968, the research has covered inorganic structures, physical metallurgy, as well as theory of electron scattering and the development of methods in this field. The current plans involve efforts in the development of crystallographic and spectroscopic methods

  16. New electronics stuff chemistry

    International Nuclear Information System (INIS)

    Byeon, Su Il

    2003-04-01

    The first part of this book is about equilibrium electrochemistry on electric thermo dynamic equilibrium state of electrochemistry, crystal defect of solid, thermodynamics on defect electron and election in semiconductor, Gawani potential, volta potential and equilibrium potential and thermodynamics application in Gawani battery. The second part deals with dynamic electrochemistry electrode reaction kinetics and corrosion potential in normal state, diffusion and transport of ion and electron and current impedance spectroscopy. It also mentions industrial electrochemistry and laboratory works in electronics chemistry course.

  17. Physical foundations of electron microscopy

    International Nuclear Information System (INIS)

    Alexander, H.

    1997-01-01

    The following topics were dealt with: Physical foundations, dynamic theory of diffraction contrasts, dynamic theory of electron diffraction, electron diffraction on crystals with defects, high-resolution electron microscopy, analytical electron microscopy

  18. Stationary Electron Atomic Model

    Science.gov (United States)

    Pressler, David E.

    1998-04-01

    I will present a novel theory concerning the position and nature of the electron inside the atom. This new concept is consistant with present experimental evidence and adheres strictly to the valence-shell electron-pair repulsion (VSEPR) model presently used in chemistry for predicting the shapes of molecules and ions. In addition, I will discuss the atomic model concept as being a true harmonic oscillator, periodic motion at resonant frequency which produces radiation at discrete frequencies or line spectra is possible because the electron is under the action of two restoring forces, electrostatic attraction and superconducting respulsion of the electron's magnetic field by the nucleus.

  19. 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.

  20. 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

  1. The auroral electron accelerator

    International Nuclear Information System (INIS)

    Bryant, D.A.; Hall, D.S.

    1989-01-01

    A model of the auroral electron acceleration process is presented in which the electrons are accelerated resonantly by lower-hybrid waves. The essentially stochastic acceleration process is approximated for the purposes of computation by a deterministic model involving an empirically derived energy transfer function. The empirical function, which is consistent with all that is known of electron energization by lower-hybrid waves, allows many, possibly all, observed features of the electron distribution to be reproduced. It is suggested that the process occurs widely in both space and laboratory plasmas. (author)

  2. 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

  3. 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

  4. Electronics Environmental Benefits Calculator

    Science.gov (United States)

    The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase, use and disposal of electronics.The EEBC estimates the environmental and economic benefits of: Purchasing Electronic Product Environmental Assessment Tool (EPEAT)-registered products; Enabling power management features on computers and monitors above default percentages; Extending the life of equipment beyond baseline values; Reusing computers, monitors and cell phones; and Recycling computers, monitors, cell phones and loads of mixed electronic products.The EEBC may be downloaded as a Microsoft Excel spreadsheet.See https://www.federalelectronicschallenge.net/resources/bencalc.htm for more details.

  5. 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...

  6. 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.

  7. 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

  8. 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...

  9. 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

  10. 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

  11. 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

  12. 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,...

  13. Electron Beam Lithography

    Science.gov (United States)

    Harriott, Lloyd R.

    1997-04-01

    Electron beams have played a significant role in semiconductor technology for more than twenty years. Early electron beam machines used a raster scanned beam spot to write patterns in electron-sensitive polymer resist materials. The main application of electron beam lithography has been in mask making. Despite the inherently high spatial resolution and wide process margins of electron beam lithography, the writing rate for semiconductor wafers has been too slow to be economically viable on a large scale. In the late 1970's, variable shape electron beam writing was developed, projecting a rectangular beam whose size can be varied for each "shot" exposure of a particular pattern, allowing some integrated circuits to be made economically where a variety of "customized" patterns are desired. In the cell or block projection electron beam exposure technique, a unit cell of a repetitive pattern is projected repeatedly to increase the level of parallelism. This can work well for highly repetitive patterns such as memory chips but is not well suited to complex varying patterns such as microprocessors. The rapid progress in the performance of integrated circuits has been largely driven by progress in optical lithography, through improvements in lens design and fabrication as well as the use of shorter wavelengths for the exposure radiation. Due to limitations from the opacity of lens and mask materials, it is unlikely that conventional optical printing methods can be used at wavelengths below 193 nm or feature sizes much below 180 nm. One candidate technology for a post-optical era is the Scattering with Angular Limitation Projection Electron-beam Lithography (SCALPEL) approach, which combines the high resolution and wide process latitude inherent in electron beam lithography with the throughput of a parallel projection system. A mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated with high energy (100 ke

  14. Electron scattering from tetrahydrofuran

    International Nuclear Information System (INIS)

    Fuss, M C; Sanz, A G; García, G; Muñoz, A; Oller, J C; Blanco, F; Do, T P T; Brunger, M J; Almeida, D; Limão-Vieira, P

    2012-01-01

    Electron scattering from Tetrahydrofuran (C 4 H 8 O) was investigated over a wide range of energies. Following a mixed experimental and theoretical approach, total scattering, elastic scattering and ionization cross sections as well as electron energy loss distributions were obtained.

  15. 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.

  16. Advances in Opto Electronics

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Advances in Opto Electronics. Optoelectronics is where electronics was 15 years back. All Optical Amplifiers and Semiconductor Amplifiers. Fastest Semiconductor (InP) switch is at 170GHz- where is terrabit ? MEMS based switches that route traffic at wavelength level ...

  17. Radiative electron capture

    International Nuclear Information System (INIS)

    Biggerstaff, J.A.; Appleton, B.R.; Datz, S.; Moak, C.D.; Neelavathi, V.N.; Noggle, T.S.; Ritchie, R.H.; VerBeek, H.

    1975-01-01

    Some data are presented for radiative electron capture by fast moving ions. The radiative electron capture spectrum is shown for O 8+ in Ag, along with the energy dependence of the capture cross-section. A discrepancy between earlier data, theoretical prediction, and the present data is pointed out. (3 figs) (U.S.)

  18. Physics and Electronics

    Science.gov (United States)

    2012-03-05

    Optoelectronics, Nanoelectronics, Terahertz Light Sources • Dr. Gernot Pomrenke •Multi-Modal Sensing • Dr. Kitt Reinhardt • GHz-THz Speed Electronics...systems & non-linear dynamics for counter DEW Complex electronics and fundamental quantum processes •new superconductors for power •non-linear

  19. Basic Electronics I.

    Science.gov (United States)

    Robertson, L. Paul

    Designed for use in basic electronics programs, this curriculum guide is comprised of twenty-nine units of instruction in five major content areas: Orientation, Basic Principles of Electricity/Electronics, Fundamentals of Direct Current, Fundamentals of Alternating Current, and Applying for a Job. Each instructional unit includes some or all of…

  20. Electron pairing without superconductivity

    Science.gov (United States)

    Levy, Jeremy

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. Support from AFOSR, ONR, ARO, NSF, DOE and NSSEFF is gratefully acknowledged.

  1. 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...

  2. Electron tunneling in chemistry

    International Nuclear Information System (INIS)

    Zamaraev, K.I.; Khajrutdinov, R.F.; Zhdanov, V.P.; Molin, Yu.N.

    1985-01-01

    Results of experimental and theoretical investigations are outlined systematically on electron tunnelling in chemical reactions. Mechanism of electron transport to great distances is shown to be characteristic to chemical compounds of a wide range. The function of tunnel reactions is discussed for various fields of chemistry, including radiation chemistry, electrochemistry, chemistry of solids, chemistry of surface and catalysis

  3. 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...

  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...

  5. 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.

  6. 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)

  7. Electrons in Molecules

    Indian Academy of Sciences (India)

    “What are electrons doing in molecules?” This is a deceptively simple question that scientists have been trying to answer for more than eighty years. With the advent of quantum mechanics in 1926, it became clear that we must understand the dynamics of electronic motion in atoms, molecules and solids in order to explain ...

  8. INDRA. Electronic Architecture

    International Nuclear Information System (INIS)

    Ganil Team.

    1993-01-01

    The INDRA multidetector electronics is described. The system is a set of 17 rings consisting of 96 ionization chambers and 180 silicon detectors plus 324 cesium iodide and 12 Phoswich scintillators. Their integrated electronic lines, the trigger modules, the control and data acquisition units are presented briefly. (R.P.) 6 figs

  9. 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.

  10. The Hydrated Electron

    Science.gov (United States)

    Herbert, John M.; Coons, Marc P.

    2017-05-01

    Existence of a hydrated electron as a byproduct of water radiolysis was established more than 50 years ago, yet this species continues to attract significant attention due to its role in radiation chemistry, including DNA damage, and because questions persist regarding its detailed structure. This work provides an overview of what is known in regards to the structure and spectroscopy of the hydrated electron, both in liquid water and in clusters [Formula: see text], the latter of which provide model systems for how water networks accommodate an excess electron. In clusters, the existence of both surface-bound and internally bound states of the excess electron has elicited much debate, whereas in bulk water there are questions regarding how best to understand the structure of the excess electron's spin density. The energetics of the equilibrium species e-(aq) and its excited states, in bulk water and at the air/water interface, are also addressed.

  11. Electronically cloaked nanoparticles

    Science.gov (United States)

    Shen, Wenqing

    The concept of electronic cloaking is to design objects invisible to conduction electrons. The approach of electronic cloaking has been recently suggested to design invisible nanoparticle dopants with electronic scattering cross section smaller than 1% of the physical cross section (pi a2), and therefore to enhance the carrier mobility of bulk materials. The proposed nanoparticles have core-shell structures. The dopants are incorporated inside the core, while the shell layer serves both as a spacer to separate the charge carriers from their parent atoms and as a cloaking shell to minimize the scattering cross section of the electrons from the ionized nanoparticles. Thermoelectric materials are usually highly doped to have enough carrier density. Using invisible dopants could achieve larger thermoelectric power factors by enhancing the electronic mobility. Core-shell nanoparticles show an advantage over one-layer nanoparticles, which are proposed in three-dimensional modulation doping. However designing such nanoparticles is not easy as there are too many parameters to be considered. This thesis first shows an approach to design hollow nanoparticles by applying constrains on variables. In the second part, a simple mapping approach is introduced where one can identify possible core-shell particles by comparing the dimensionless parameters of chosen materials with provided maps. In both parts of this work, several designs with realistic materials were made and proven to achieve electronic cloaking. Improvement in the thermoelectric power factor compared to the traditional impurity doping method was demonstrated in several cases.

  12. 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.

  13. Dose calculation for electrons

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    1995-01-01

    The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)

  14. Electron Cooling of RHIC

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Barton, D.S.; Beavis, D.B.; Blaskiewicz, M.; Brennan, J.M.; Burrill, A.; Calaga, R.; Cameron, P.; Chang, X.Y.; Connolly, R.; Eidelman, Yu.I.; Fedotov, A.V.; Fischer, W.; Gassner, D.M.; Hahn, H.; Harrison, M.; Hershcovitch, A.; Hseuh, H.-C.; Jain, A.K.; Johnson, P.D.J.; Kayran, D.; Kewisch, J.; Lambiase, R.F.; Litvinenko, V.; MacKay, W.W.; Mahler, G.J.; Malitsky, N.; McIntyre, G.T.; Meng, W.; Mirabella, K.A.M.; Montag, C.; Nehring, T.C.N.; Nicoletti, T.; Oerter, B.; Parzen, G.; Pate, D.; Rank, J.; Rao, T.; Roser, T.; Russo, T.; Scaduto, J.; Smith, K.; Trbojevic, D.; Wang, G.; Wei, J.; Williams, N.W.W.; Wu, K.-C.; Yakimenko, V.; Zaltsman, A.; Zhao, Y.; Abell, D.T.; Bruhwiler, D.L.; Bluem, H.; Burger, A.; Cole, M.D.; Favale, A.J.; Holmes, D.; Rathke, J.; Schultheiss, T.; Todd, A.M.M.; Burov, A.V.; Nagaitsev, S.; Delayen, J.R.; Derbenev, Y.S.; Funk, L. W.; Kneisel, P.; Merminga, L.; Phillips, H.L.; Preble, J.P.; Koop, I.; Parkhomchuk, V.V.; Shatunov, Y.M.; Skrinsky, A.N.; Koop, I.; Parkhomchuk, V.V.; Shatunov, Y.M.; Skrinsky, A.N.; Sekutowicz, J.S.

    2005-01-01

    We report progress on the R and 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 and 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.agsrhichome.bnl.gov/eCool/

  15. Electron Cooling of RHIC

    Energy Technology Data Exchange (ETDEWEB)

    I. Ben-Zvi; D.S. Barton; D.B. Beavis; M. Blaskiewicz; J.M. Brennan; A. Burrill; R. Calaga; P. Cameron; X.Y. Chang; R. Connolly; Yu.I. Eidelman; A.V. Fedotov; W. Fischer; D.M. Gassner; H. Hahn; M. Harrison; A. Hershcovitch; H.-C. Hseuh; A.K. Jain; P.D.J. Johnson; D. Kayran; J. Kewisch; R.F. Lambiase; V. Litvinenko; W.W. MacKay; G.J. Mahler; N. Malitsky; G.T. McIntyre; W. Meng; K.A.M. Mirabella; C. Montag; T.C.N. Nehring; T. Nicoletti; B. Oerter; G. Parzen; D. Pate; J. Rank; T. Rao; T. Roser; T. Russo; J. Scaduto; K. Smith; D. Trbojevic; G. Wang; J. Wei; N.W.W. Williams; K.-C. Wu; V. Yakimenko; A. Zaltsman; Y. Zhao; D.T. Abell; D.L. Bruhwiler; H. Bluem; A. Burger; M.D. Cole; A.J. Favale; D. Holmes; J. Rathke; T. Schultheiss; A.M.M. Todd; A.V. Burov; S. Nagaitsev; J.R. Delayen; Y.S. Derbenev; L. W. Funk; P. Kneisel; L. Merminga; H.L. Phillips; J.P. Preble; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; I. Koop; V.V. Parkhomchuk; Y.M. Shatunov; A.N. Skrinsky; J.S. Sekutowicz

    2005-05-16

    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.agsrhichome.bnl.gov/eCool/.

  16. 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...

  17. 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

  18. Microscopy with slow electrons

    International Nuclear Information System (INIS)

    Frank, L.; Muellerova, I.; Delong, A.

    1994-01-01

    Low energy microscopy is treated as the low energy limit of electron microscopy as a whole in all its basic branches, i.e., the emission, transmission and scanning microscopy. The instrumental and methodological aspects are briefly discussed. They include the interaction of electrons with a solid, the contrast formation mechanisms, the instrumentation problems, and actual progress achieved in all three types of microscopy from the point of view of lowering the energy of electrons, impacting or leaving the specimen, down to the low energy range below 5 keV and the very low energy range below 50 eV. (author) 62 refs., 27 figs., 3 tabs

  19. 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

  20. Free-electron lasers

    International Nuclear Information System (INIS)

    Brau, C.A.

    1990-01-01

    Free-electron lasers represent an altogether new and exciting class of coherent optical sources. Making use of a simple and elegant gain medium - an electron beam in a magnetic field - they have already demonstrated broad wavelength tunability and excellent optical-beam quality. For the future they offer the possibility of generating the greatest focused power ever achieved by a laser. But even before this is achieved, the unique advantages of free-electron lasers, especially their tunability, will make them useful for a variety of important applications in science, medicine, and industry. (author)

  1. 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.

  2. 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

  3. 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

  4. 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

  5. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  6. 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

  7. 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.

  8. Modern dictionary of electronics

    CERN Document Server

    Graf, Rudolf F

    1999-01-01

    Included in this fully revised classic are well over 28,000 terms, phrases, acronyms, and abbreviations from the ever-expanding worlds of consumer electronics, optics, microelectronics, computers, communications, and medical electronics. From the basic elements of theory to the most cutting-edge circuit technology, this book explains it all in both words and pictures.For easy reference, the author has provided definitions for standard abbreviations and equations as well as tables of SI (International System of Units) units, measurements, and schematic symbolsModern Dictionary of Electronics is

  9. Single Electron Tunneling

    International Nuclear Information System (INIS)

    Ruggiero, Steven T.

    2005-01-01

    Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

  10. Electron collisions with biomolecules

    International Nuclear Information System (INIS)

    McKoy, V; Winstead, C

    2008-01-01

    We report on results of recent studies of collisions of low-energy electrons with nucleobases and other DNA constituents. A particular focus of these studies has been the identification and characterization of resonances that play a role in electron attachment leading to strand breaks in DNA. Comparison of the calculated resonance positions with results of electron transmission measurements is quite encouraging. However, the higher-lying π* resonances of the nucleobases appear to be of mixed elastic and core-excited character. Such resonant channel coupling raises the interesting possibility that the higher π*resonances in the nucleobases may promote dissociation of DNA by providing doorway states to triplet excited states.

  11. 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

  12. 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.

  13. 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.

  14. Electron capture and loss

    International Nuclear Information System (INIS)

    Horsdal Pedersen, E.

    1978-01-01

    Two limiting cases of electron capture leading to the formation of heavy ions with inner-shell vacancies are discussed. The first case is electron capture by fast (v>v 0 ) light ions in heavy targets. This process results, with a large probability, in the formation of inner-shell vacancies in the target. The second case is electron capture by, highly heavy charged ions in light targets, resulting in fast beam particles with K-shell vacancies which decay by means of polarised x rays. It is possible to get a quantitative understanding of the importance of capture from inner shells of the target in fast collisions between light projectiles and heavy targets and of the polarisation of x rays following electron capture by heavy, highly charged particles in light targets by a consideration of the matrix element in the Brinkman-Kramers approximation. (JIW)

  15. 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...

  16. High brightness electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, R.L.

    1995-07-01

    High energy physics accelerators and free electron lasers put increased demands on the electron beam sources. This paper describes the present research on attaining intense bright electron beams using photoinjectors. Recent results from the experimental programs will be given. The performance advantages and difficulties presently faced by researchers will be discussed, and the following topics will be covered. Progress has been made in photocathode materials, both in lifetime and quantum efficiency. Cesium telluride has demonstrated significantly longer lifetimes than cesium antimonide at 10{sup {minus}8} torr. However, the laser system is more difficult because cesium telluride requires quadrupled YLF instead of the doubled YLF required for cesium antimonide. The difficulty in using photoinjectors is primarily the drive laser, in particular the amplitude stability. Finally, emittance measurements of photoinjector systems can be complicated by the non-thermal nature of the electron beam. An example of the difficulty in measuring beam emittance is given.

  17. Electron beam curing paint

    International Nuclear Information System (INIS)

    Maruyama, Tsutomu

    1991-04-01

    Electron beam curing (EBC) type paint is paint that is specially prepared so that it can be cured and dried by electron beam irradiation. Electron beam irradiation achieves hardly any curing and drying of ordinary normal-temperature drying type paint or heat-drying type paint. The main type of paint in which an electron beam produces a curing reaction is one in which a radical polymerization reaction takes place under irradiation. The use of this EBC painting - drying system has been considered for a variety of fields since it has a number of special features such as the fact that the paint dries instantaneously, no heat is applied and no solvent is used. (Author)

  18. 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.

  19. Advances in electron dosimetry

    International Nuclear Information System (INIS)

    Harder, D.

    1980-04-01

    Starting from the two most important interactions of electrons with matter, energy loss and scattering, a review is given of a number of effects which are important in electron dosimetry. For determining the absorbed dose in a phantom by means of ionization chambers, imformation is required on the electron spectrum at the location of the measurement, on the stopping powers of different materials and on disturbances such as the displacement of the effective point of measurements from the centre of the chamber. By means of figures and photographs of electron traces in bubble chambers, the origin of the formation of the absorbed dose maximum in a phantom is explained. It is shown, how by multiple scattering, the similarity of dose distributions in different media can be explained and how by Monte-Carlo calculations absorbed dose distributions in the surroundings of inhomogeneities (e.g. cavities) in a phantom can be determined. (orig.) [de

  20. Electron linac injector developments

    International Nuclear Information System (INIS)

    Fraser, J.S.

    1986-01-01

    There is a continuing demand for improved injectors for electron linacs. Free-electron laser (FEL) oscillators require pulse trains of high brightness and, in some applications, high average power at the same time. Wakefield-accelerator and laser-acceleration experiments require isolated bunches of high peak brightness. Experiments with alkali-halide photoemissive and thermionic electron sources in rf cavities for injector applications are described. For isolated pulses, metal photocathodes (illuminated by intense laser pulses) are being employed. Reduced emittance growth in high-peak-current electron injectors may be achieved by linearizing the cavity electric field's radial component and by using high field strengths at the expense of lower shunt impedance. Harmonically excited cavities have been proposed for enlarging the phase acceptance of linac cavities and thereby reducing the energy spread produced in the acceleration process. Operation of injector linacs at a subharmonic of the main linac frequency is also proposed for enlarging the phase acceptance

  1. 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.

  2. Magnetic electron scattering

    International Nuclear Information System (INIS)

    Peterson, G.A.

    1989-01-01

    We briefly review some of the motivations, early results, and techniques of magnetic elastic and inelastic electron-nucleus scattering. We then discuss recent results, especially those acquired at high momentum transfers. 50 refs., 19 figs

  3. Elastic magnetic electron scattering

    International Nuclear Information System (INIS)

    Sick, I.

    1985-01-01

    The paper surveys the field of elastic magnetic electron scattering. Magnetic scattering as a configuration analyzer; magnetic form factors of high multipole order; absolute spectroscopic factors; and non-nucleonic constituents; are all discussed. (U.K.)

  4. Electronic personal dosemeters

    International Nuclear Information System (INIS)

    Marshall, T.O.; Bartlett, D.T.; Burgess, P.H.; Cranston, C.S.; Higginbottom, D.J.; Sutton, K.W.

    1990-01-01

    Personal dosimetry services approved by their national authorities for category A workers, invariably use passive dosemeters incorporating photographic film or thermoluminescent detectors. However, the performance characteristics of electronic dosemeters has improved substantially over the past decade to such an extent that in the opening lecture of the Solid State Dosimetry Conference at Oxford in 1986 the development of an electronic 'smart card' based on a silicon detector was briefly discussed. This idea has been taken up and at least one development programme is in progress aimed at the production of an electronic dosemeter suitable for use as a legal device. The more important performance requirements of personal dosemeters for this purpose are discussed and the earlier electronic dosemeter designs and the latest devices under development to meet this specification are compared. (author)

  5. ORELA electron guns

    International Nuclear Information System (INIS)

    Christian, O.W.; Lewis, T.A.

    1981-09-01

    The most recent information concerning the production and performance of ORELA electron guns is presented. Included are descriptions of procedures for gun fabrication, cathode conditioning and high voltage processing. Highlights of the performance characteristics are also included

  6. 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,...

  7. Electronic Falling Body Simulator

    Science.gov (United States)

    Goodman, John M.

    1975-01-01

    Describes an analog electronic simulator for the motion of an object projected horizontally in a vertical acceleration field. The device features adjustable values for the horizontal speeds and "gravity." Trajectories are displayed on an oscilloscope. (Author/CP)

  8. PNC - Electron linac concept

    International Nuclear Information System (INIS)

    Tani, S.; Nakamura, H.

    1997-01-01

    The possibility of using an electron accelerator for the transmutation of fission products, particularly Cs-137 and Sr-90, through photonuclear reactions is studied at the Power Reactor and Nuclear Fuel Development Corporation (PNC)

  9. 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...

  10. 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......; a method of preparing a zinc oxide electron transporting layer, which method comprises: i) coating a substrate with the coating ink of the present invention to form a film; ii) drying the film; and iii) heating the dry film to convert the zinc acetate substantially to ZnO; a method of preparing an organic...... photovoltaic device or an organic LED having a zinc oxide electron transport layer, the method comprising, in this order: a) providing a substrate bearing a first electrode layer; b) forming an electron transport layer according to the following method: i) coating a coating ink comprising an ink according...

  11. 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.

  12. PREFACE: Spin Electronics

    Science.gov (United States)

    Dieny, B.; Sousa, R.; Prejbeanu, L.

    2007-04-01

    Conventional electronics has in the past ignored the spin on the electron, however things began to change in 1988 with the discovery of giant magnetoresistance in metallic thin film stacks which led to the development of a new research area, so called spin-electronics. In the last 10 years, spin-electronics has achieved a number of breakthroughs from the point of view of both basic science and application. Materials research has led to several major discoveries: very large tunnel magnetoresistance effects in tunnel junctions with crystalline barriers due to a new spin-filtering mechanism associated with the spin-dependent symmetry of the electron wave functions new magnetic tunnelling barriers leading to spin-dependent tunnelling barrier heights and acting as spin-filters magnetic semiconductors with increasingly high ordering temperature. New phenomena have been predicted and observed: the possibility of acting on the magnetization of a magnetic nanostructure with a spin-polarized current. This effect, due to a transfer of angular momentum between the spin polarized conduction electrons and the local magnetization, can be viewed as the reciprocal of giant or tunnel magnetoresistance. It can be used to switch the magnetization of a magnetic nanostructure or to generate steady magnetic excitations in the system. the possibility of generating and manipulating spin current without charge current by creating non-equilibrium local accumulation of spin up or spin down electrons. The range of applications of spin electronics materials and phenomena is expanding: the first devices based on giant magnetoresistance were the magnetoresistive read-heads for computer disk drives. These heads, introduced in 1998 with current-in plane spin-valves, have evolved towards low resistance tunnel magnetoresistice heads in 2005. Besides magnetic recording technology, these very sensitive magnetoresistive sensors are finding applications in other areas, in particular in biology. magnetic

  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. Electron attachment cross sections obtained from electron attachment spectroscopy

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  15. 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.

  16. ELECTRONIC BUSINESS IN BUSINESS

    OpenAIRE

    Lucian Constantin Gabriel Budacia; Elisabeta Andreea Budacia

    2008-01-01

    The management of a business in the digital economy is based on a management process called digital management. Business in the digital economy integrates information technologies and communications within its activities and may be partially or totally electronic. Management of the business is carried out using information systems that support for the substantiation and decisions. Business electronic involve a complete change in how the customer is viewed in relation to the organization; requ...

  17. 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

  18. 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

  19. Electricity electron measurement

    International Nuclear Information System (INIS)

    Kim, Sang Jin; Sung, Rak Jin

    1985-11-01

    This book deals with measurement of electricity and electron. It is divided into fourteen chapters, which depicts basic of electricity measurement, unit and standard, important electron circuit for measurement, instrument of electricity, impedance measurement, power and power amount measurement, frequency and time measurement, waveform measurement, record instrument and direct viewing instrument, super high frequency measurement, digital measurement on analog-digital convert, magnetic measurement on classification by principle of measurement, measurement of electricity application with principle sensors and systematization of measurement.

  20. 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.

  1. Weakly oval electron lense

    International Nuclear Information System (INIS)

    Daumenov, T.D.; Alizarovskaya, I.M.; Khizirova, M.A.

    2001-01-01

    The method of the weakly oval electrical field getting generated by the axially-symmetrical field is shown. Such system may be designed with help of the cylindric form coaxial electrodes with the built-in quadrupole duplet. The singularity of the indicated weakly oval lense consists of that it provides the conducting both mechanical and electronic adjustment. Such lense can be useful for elimination of the near-axis astigmatism in the electron-optical system

  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. Joint Services Electronics Program.

    Science.gov (United States)

    1986-09-30

    electronic multi-dimensional signal processing, (3) electronic time-variant signal processing, and (4) digital time series analysis with applications to...Variant Signal Processing ............... 19 Res. Unit IE85-3 Digital Time Series Analysis with Applications to Nonlinear Wave Phenomena...Boewering, Physics Scott Levinson, ECE T.L. Boyd, Physics Bin-Wah Lin, ECE Robert Brecha , Physics Jorge Castro Luengo, Physics Mike Bruce, Physics * Henry

  4. 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)....

  5. 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.

  6. 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

  7. 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.

  8. Nuclear electronics laboratory manual

    International Nuclear Information System (INIS)

    1984-05-01

    The Nuclear Electronics Laboratory Manual is a joint product of several electronics experts who have been associated with IAEA activity in this field for many years. The manual does not include experiments of a basic nature, such as characteristics of different active electronics components. It starts by introducing small electronics blocks, employing one or more active components. The most demanding exercises instruct a student in the design and construction of complete circuits, as used in commercial nuclear instruments. It is expected that a student who completes all the experiments in the manual should be in a position to design nuclear electronics units and also to understand the functions of advanced commercial instruments which need to be repaired or maintained. The future tasks of nuclear electronics engineers will be increasingly oriented towards designing and building the interfaces between a nuclear experiment and a computer. The manual pays tribute to this development by introducing a number of experiments which illustrate the principles and the technology of interfacing

  9. Electron-electron attraction in an engineered electromechanical system

    Science.gov (United States)

    Széchenyi, Gábor; Pályi, András; Droth, Matthias

    2017-12-01

    Two electrons in a quantum dot repel each other: their interaction can be characterized by a positive interaction energy. From the theory of superconductivity, we also know that mechanical vibrations of the crystal lattice can make the electron-electron interaction attractive. Analogously, if a quantum dot interacts with a mechanical degree of freedom, the effective interaction energy can be negative; that is, the electron-electron interaction might be attractive. In this work, we propose and theoretically study an engineered electromechanical system that exhibits electron-electron attraction: a quantum dot suspended on a nonlinear mechanical resonator, tuned by a bottom and a top gate electrode. We focus on the example of a dot embedded in a suspended graphene ribbon, for which we identify conditions for electron-electron attraction. Our results suggest the possibility of electronic transport via tunneling of packets of multiple electrons in such devices, similar to that in superconducting nanostructures, but without the use of any superconducting elements.

  10. 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

  11. Analytics on Transmission Electron Microscopy

    International Nuclear Information System (INIS)

    Keum, Dong Hwa; Kim, Geung Ho; Lee, Hwak Ju and others

    1996-06-01

    This book gives descriptions of transmission electron microscopy, which deals with electron microscopy and materials science, history of electron microscopy, application of analytics on transmission electron microscopy, machine requirement of transmission electron microscopy like electron gun and TEM image and function, crystal diffraction, electron diffraction, Kikuchi's diffraction figure, analysis of diffraction figure, contrast of TEM image like absorption contrast, and phase contrast, Fresnel's diffraction and TEM contrast, thickness fringe, column approximation, analysis of diffraction contrast, image simulation, and electron energy loss spectrometry.

  12. 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.

  13. Electron Accumulative Molecules.

    Science.gov (United States)

    Buades, Ana B; Sanchez Arderiu, Víctor; Olid-Britos, David; Viñas, Clara; Sillanpää, Reijo; Haukka, Matti; Fontrodona, Xavier; Paradinas, Markos; Ocal, Carmen; Teixidor, Francesc

    2018-02-28

    With the goal to produce molecules with high electron accepting capacity and low reorganization energy upon gaining one or more electrons, a synthesis procedure leading to the formation of a B-N(aromatic) bond in a cluster has been developed. The research was focused on the development of a molecular structure able to accept and release a specific number of electrons without decomposing or change in its structural arrangement. The synthetic procedure consists of a parallel decomposition reaction to generate a reactive electrophile and a synthesis reaction to generate the B-N(aromatic) bond. This procedure has paved the way to produce the metallacarboranylviologen [M(C 2 B 9 H 11 )(C 2 B 9 H 10 )-NC 5 H 4 -C 5 H 4 N-M'(C 2 B 9 H 11 )(C 2 B 9 H 10 )] (M = M' = Co, Fe and M = Co and M' = Fe) and semi(metallacarboranyl)viologen [3,3'-M(8-(NC 5 H 4 -C 5 H 4 N-1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] (M = Co, Fe) electron cumulative molecules. These molecules are able to accept up to five electrons and to donate one in single electron steps at accessible potentials and in a reversible way. By targeted synthesis and corresponding electrochemical tests each electron transfer (ET) step has been assigned to specific fragments of the molecules. The molecules have been carefully characterized, and the electronic communication between both metal centers (when this situation applies) has been definitely observed through the coplanarity of both pyridine fragments. The structural characteristics of these molecules imply a low reorganization energy that is a necessary requirement for low energy ET processes. This makes them electronically comparable to fullerenes, but on their side, they have a wide range of possible solvents. The ET from one molecule to another has been clearly demonstrated as well as their self-organizing capacity. We consider that these molecules, thanks to their easy synthesis, ET, self-organizing capacity, wide range of solubility, and easy processability, can

  14. 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.

  15. 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.

  16. Electron Interactions in Graphene

    Science.gov (United States)

    Kim, Philip

    2011-03-01

    Electrons confined in two dimensions (2D) can exhibit strongly correlated states. Recent experimental discovery of integer and fractional quantum Hall effect in graphene amplified interest in correlated 2D electronic systems, owning to presence of the unusual topological phase associated with zero effective mass of charge carriers. In this talk, we will discuss the role of the many-body effects due to the electron-electron interaction in graphene manifested in electron transport phenomena. In particular, we will discuss the nature unusual spontaneous symmetry breaking Landau levels graphene under the extreme quantum condition, the appearance of unique low density insulating states and fractional quantum Hall states. Employing extremely high quality samples obtained by suspending graphene and graphene on atomically flat defect free insulating substrate such as hexa-bron nitride, we now investigate various broken symmetry states under high magnetic field. The nature of these broken symmetry state can be explained generally considering underlying SU(4) symmetry in the single particle level of the Landau levels.

  17. Politics Under Electronic Simultaneity

    Directory of Open Access Journals (Sweden)

    Valery P. Terin

    2014-01-01

    Full Text Available In contradistinction to the book and the other typographic products, the electronic media operates on a 24-hour-a-day basis evoking simultaneity as the guiding mode of perception and thinking for all those under its influence. The discovery of this fact manifested itself in the formation and development of the managerial technologies operating by means of the electronic information environment and following the principle of simultaneity in the first place. Thus, at the end of the 1960s already the election campaigns in the U.S.A. began to operate on the basis of the final cause as the guiding principle of the country's mass consciousness motivating to carry out each particular event as if already rejoicing at the victory. With this in mind, there emerged a problem of applying this approach with its enormous managerial potential elsewhere. To add, simultaneity as a norm of perception and thinking turned out to be increasingly important with the advent of the electrical telegraph and the press relying on its short disconnected messages instantaneously arriving from all parts of the world. All the other media, which emerged in the wake of this development, has served to fortify this mode of thought as governing in the electronic information environment. The potential of the electronically operating global managerial technologies is quickly growing. The article also deals with the information overload and pattern recognition problem understood in managerial terms as well as mythologization and demythologization processes as they are necessitated by the electronic media coverage worldwide.

  18. 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.

  19. 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.

  20. 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.

  1. Wireless Biological Electronic Sensors.

    Science.gov (United States)

    Cui, Yue

    2017-10-09

    The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

  2. 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...

  3. Foil Electron Multiplier

    Science.gov (United States)

    Funsten, Herbert O.; Baldonado, Juan R.; Dors, Eric E.; Harper, Ronnie W.; Skoug, Ruth M.

    2006-03-28

    An apparatus for electron multiplication by transmission that is designed with at least one foil having a front side for receiving incident particles and a back side for transmitting secondary electrons that are produced from the incident particles transiting through the foil. The foil thickness enables the incident particles to travel through the foil and continue on to an anode or to a next foil in series with the first foil. The foil, or foils, and anode are contained within a supporting structure that is attached within an evacuated enclosure. An electrical power supply is connected to the foil, or foils, and the anode to provide an electrical field gradient effective to accelerate negatively charged incident particles and the generated secondary electrons through the foil, or foils, to the anode for collection.

  4. ELECTRON EMISSION REGULATING MEANS

    Science.gov (United States)

    Brenholdt, I.R.

    1957-11-19

    >An electronic regulating system is described for controlling the electron emission of a cathode, for example, the cathode in a mass spectrometer. The system incorporates a transformer having a first secondary winding for the above-mentioned cathode and a second secondary winding for the above-mentioned cathode and a second secondary winding load by grid controlled vacuum tubes. A portion of the electron current emitted by the cathode is passed through a network which develops a feedback signal. The system arrangement is completed by using the feedback signal to control the vacuum tubes in the second secondary winding through a regulator tube. When a change in cathode emission occurs, the feedback signal acts to correct this change by adjusting the load on the transformer.

  5. Electronics a systems approach

    CERN Document Server

    Storey, Neil

    2017-01-01

    Electronics plays a central role in our everyday lives. It is at the heart of almost all of today's essential technology, from mobile phones to computers and from cars to power stations. As such, all engineers, scientists and technologists need to have a fundamental understanding of this exciting subject, and for many this will just be the beginning. Now in its sixth edition, Electronics: A Systems Approach provides an outstanding introduction to this fast-moving and important field. Comprehensively revised and updated to cover the latest developments in the world of electronics, the text continues to use Neil Storey's established and well-respected systems approach. It introduces the basic concepts first before progressing to a more advanced analysis, enabling you to contextualise what a system is designed to achieve before tackling the intricacies of designing or analysing its various components with confidence. This book is accompanied by a website which contains over 100 video tutorials to help explain ke...

  6. 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

  7. 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

  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. 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

  10. 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

  11. Auroral electron acceleration

    International Nuclear Information System (INIS)

    Bryant, D.A.

    1989-10-01

    Two theories of auroral electron acceleration are discussed. Part 1 examines the currently widely held view that the acceleration is an ordered process in a quasi-static electric field. It is suggested that, although there are many factors seeming to support this theory, the major qualifications and uncertainties that have been identified combine to cast serious doubt over its validity. Part 2 is devoted to a relatively new interpretation in terms of stochastic acceleration in turbulent electric fields. This second theory, which appears to account readily for most known features of the electron distribution function, is considered to provide a more promising approach to this central question in magnetospheric plasma physics. (author)

  12. 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

  13. 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

  14. Electronic health record

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2011-01-01

    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...

  15. Electronic health records

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2011-01-01

    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...

  16. Innovations in electronic services

    Directory of Open Access Journals (Sweden)

    Dagmara Wach

    2011-12-01

    Full Text Available Summarry Existence in electronic business has become increasingly difficult. High competition and considerable financial resources needed to enter electronic market are the problems of most micro and small sized enterprises, starting or developing their business. Nevertheless, there is a market niche for them, which can ensure success and grant partial financing of the business. This niche are small web projects, providing the customer with personalized service, hitting his tastes and meeting immediate needs. A projects that large websites are unable to perform. Financial sourcing of those projects comes from EU subsidies, in the framework of the Działanie 8.1. PO IG, 2007-2013.

  17. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1972-01-01

    Electronic Devices and Circuits, Volume 3 provides a comprehensive account on electronic devices and circuits and includes introductory network theory and physics. The physics of semiconductor devices is described, along with field effect transistors, small-signal equivalent circuits of bipolar transistors, and integrated circuits. Linear and non-linear circuits as well as logic circuits are also considered. This volume is comprised of 12 chapters and begins with an analysis of the use of Laplace transforms for analysis of filter networks, followed by a discussion on the physical properties of

  18. Precision electron polarimetry

    International Nuclear Information System (INIS)

    Chudakov, E.

    2013-01-01

    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. 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

  19. Corrosion in Electronics

    DEFF Research Database (Denmark)

    Ambat, Rajan; Gudla, Helene Virginie Conseil; Verdingovas, Vadimas

    2017-01-01

    and high density packing combined with the use of several materials, which can undergo electrochemical corrosion in the presence of water film formed due to humidity exposure and bias conditions on the PCBA surface. This article provides a short review of the corrosion reliability issues of electronics due...... to the use of electronics under varying humidity conditions. Important PCBA aspects, which are fundamental to the corrosion cell formation under humid conditions, are discussed. Effect of hygroscopic residues from the process and service and their role in assisting water film build up and corrosion...... is presented. Various failure modes resulting from the corrosion and influence factors are discussed including humid and gaseous conditions....

  20. 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.

  1. The ATLAS TRT electronics

    Science.gov (United States)

    ATLAS TRT Collaboration; Abat, E.; Addy, T. N.; Åkesson, T. P. A.; Alison, J.; Anghinolfi, F.; Arik, E.; Arik, M.; Atoian, G.; Auerbach, B.; Baker, O. K.; Banas, E.; Baron, S.; Bault, C.; Becerici, N.; Beddall, A.; Beddall, A. J.; Bendotti, J.; Benjamin, D. P.; Bertelsen, H.; Bingul, A.; Blampey, H.; Bocci, A.; Bochenek, M.; Bondarenko, V. G.; Bychkov, V.; Callahan, J.; Capeáns Garrido, M.; Cardiel Sas, L.; Catinaccio, A.; Cetin, S. A.; Chandler, T.; Chritin, R.; Cwetanski, P.; Dam, M.; Danielsson, H.; Danilevich, E.; David, E.; Degenhardt, J.; Di Girolamo, B.; Dittus, F.; Dixon, N.; Dogan, O. B.; Dolgoshein, B. A.; Dressnandt, N.; Driouchi, C.; Ebenstein, W. L.; Eerola, P.; Egede, U.; Egorov, K.; Evans, H.; Farthouat, P.; Fedin, O. L.; Fowler, A. J.; Fratina, S.; Froidevaux, D.; Fry, A.; Gagnon, P.; Gavrilenko, I. L.; Gay, C.; Ghodbane, N.; Godlewski, J.; Goulette, M.; Gousakov, I.; Grigalashvili, N.; Grishkevich, Y.; Grognuz, J.; Hajduk, Z.; Hance, M.; Hansen, F.; Hansen, J. B.; Hansen, P. H.; Hare, G. A.; Harvey, A., Jr.; Hauviller, C.; High, A.; Hulsbergen, W.; Huta, W.; Issakov, V.; Istin, S.; Jain, V.; Jarlskog, G.; Jeanty, L.; Kantserov, V. A.; Kaplan, B.; Kapliy, A. S.; Katounin, S.; Kayumov, F.; Keener, P. T.; Kekelidze, G. D.; Khabarova, E.; Khristachev, A.; Kisielewski, B.; Kittelmann, T. H.; Kline, C.; Klinkby, E. B.; Klopov, N. V.; Ko, B. R.; Koffas, T.; Kondratieva, N. V.; Konovalov, S. P.; Koperny, S.; Korsmo, H.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; LeBihan, A.-C.; LeGeyt, B. C.; Levterov, K.; Lichard, P.; Lindahl, A.; Lisan, V.; Lobastov, S.; Loginov, A.; Loh, C. W.; Lokwitz, S.; Long, M. C.; Lucas, S.; Lucotte, A.; Luehring, F.; Lundberg, B.; Mackeprang, R.; Maleev, V. P.; Manara, A.; Mandl, M.; Martin, A. J.; Martin, F. F.; Mashinistov, R.; Mayers, G. M.; McFarlane, K. W.; Mialkovski, V.; Mills, B. M.; Mindur, B.; Mitsou, V. A.; Mjörnmark, J. U.; Morozov, S. V.; Morris, E.; Mouraviev, S. V.; Muir, A. M.; Munar, A.; Nadtochi, A. V.; Nesterov, S. Y.; Newcomer, F. M.; Nikitin, N.; Novgorodova, O.; Novodvorski, E. G.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olivito, D.; Olszowska, J.; Ostrowicz, W.; Passmore, M. S.; Patrichev, S.; Penwell, J.; Perez-Gomez, F.; Peshekhonov, V. D.; Petersen, T. C.; Petti, R.; Placci, A.; Poblaguev, A.; Pons, X.; Price, M. J.; Røhne, O.; Reece, R. D.; Reilly, M. B.; Rembser, C.; Romaniouk, A.; Rousseau, D.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Söderberg, M.; Savenkov, A.; Saxon, J.; Scandurra, M.; Schegelsky, V. A.; Scherzer, M. I.; Schmidt, M. P.; Schmitt, C.; Sedykh, E.; Seliverstov, D. M.; Shin, T.; Shmeleva, A.; Sivoklokov, S.; Smirnov, S. Yu; Smirnova, L.; Smirnova, O.; Smith, P.; Sosnovtsev, V. V.; Sprachmann, G.; Subramania, S.; Suchkov, S. I.; Sulin, V. V.; Szczygiel, R. R.; Tartarelli, G.; Thomson, E.; Tikhomirov, V. O.; Tipton, P.; Valls Ferrer, J. A.; Van Berg, R.; Vassilakopoulos, V. I.; Vassilieva, L.; Wagner, P.; Wall, R.; Wang, C.; Whittington, D.; Williams, H. H.; Zhelezko, A.; Zhukov, K.

    2008-06-01

    The ATLAS inner detector consists of three sub-systems: the pixel detector spanning the radius range 4cm-20cm, the semiconductor tracker at radii from 30 to 52 cm, and the transition radiation tracker (TRT), tracking from 56 to 107 cm. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift tubes (or straws) and of electron identification based on transition radiation from fibres or foils interleaved between the straws themselves. This paper describes the on and off detector electronics for the TRT as well as the TRT portion of the data acquisition (DAQ) system.

  2. 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.

  3. Electron localization in water clusters

    International Nuclear Information System (INIS)

    Landman, U.; Barnett, R.N.; Cleveland, C.L.; Jortner, J.

    1987-01-01

    Electron attachment to water clusters was explored by the quantum path integral molecular dynamics method, demonstrating that the energetically favored localization mode involves a surface state of the excess electron, rather than the precursor of the hydrated electron. The cluster size dependence, the energetics and the charge distribution of these novel electron-cluster surface states are explored. 20 refs., 2 figs., 1 tab

  4. TRANSIENT ELECTRONICS CATEGORIZATION

    Science.gov (United States)

    2017-08-24

    building transience into critical electronic systems is not new. Anyone who watched the 1970’s television series Mission Impossible is familiar with the...Madou, “MEMS fabrication”, in The MEMS Handbook , CRC Press, New York, NY, Ch. 16, pp1-183, (2002). 20 K. R. Williams, K. Gupta, and M. Wasilik

  5. 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.

  6. Electronics Book II.

    Science.gov (United States)

    Johnson, Dennis; And Others

    This manual, the second of three curriculum guides for an electronics course, is intended for use in a program combining vocational English as a second language (VESL) with bilingual vocational education. Ten units cover the electrical team, Ohm's law, Watt's law, series resistive circuits, parallel resistive circuits, series parallel circuits,…

  7. Joint Services Electronics Program.

    Science.gov (United States)

    1987-12-31

    Graduate Students: R. J. Brecha, M. G. Raizen, Min Xiao, L. A. Orozco, L. A. Wu, W. David Lee, Heung Choo , Silvania Pereira A. RESEARCH OBJECTIVES: The...P.O. Box 12211 Dr. Donn V. Campbell % Research Triangle Park, NC 27709-2211 U.S. Army Communications-Electronics Command Dr. Jimmie R. Suttle ATTN

  8. electronic and structural investigations

    Indian Academy of Sciences (India)

    2018-03-30

    Mar 30, 2018 ... Indian Academy of Sciences https://doi.org/10.1007/s12034-018-1572-8. Milling effect on the photo-activated properties of TiO2 nanoparticles: electronic and structural investigations. YOUCEF MESSAI1,2, BERTRAND VILENO2,4, DAVID MARTEL3, PHILIPPE TUREK2,4 and. DJAMEL EDDINE MEKKI1,∗.

  9. Electrons in Condensed Matter

    Indian Academy of Sciences (India)

    help conduct electrical current, as described below, and the high electrical conductivity of metals such as aluminium is ascribed to their having a high density of ..... electron interactions and some disorder are essential to the observation of these unique quantum phenomena. Laughlin predicted that the lowest stable excited ...

  10. Japan's electronic packaging technologies

    Science.gov (United States)

    Tummala, Rao R.; Pecht, Michael

    1995-01-01

    The JTEC panel found Japan to have significant leadership over the United States in the strategic area of electronic packaging. Many technologies and products once considered the 'heart and soul' of U.S. industry have been lost over the past decades to Japan and other Asian countries. The loss of consumer electronics technologies and products is the most notable of these losses, because electronics is the United States' largest employment sector and is critical for growth businesses in consumer products, computers, automobiles, aerospace, and telecommunications. In the past there was a distinction between consumer and industrial product technologies. While Japan concentrated on the consumer market, the United States dominated the industrial sector. No such distinction is anticipated in the future; the consumer-oriented technologies Japan has dominated are expected to characterize both domains. The future of U.S. competitiveness will, therefore, depend on the ability of the United States to rebuild its technological capabilities in the area of portable electronic packaging.

  11. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the ...

  12. Electronic Load Bank

    Science.gov (United States)

    Huston, Steven W.

    1992-01-01

    Electronic load-bank circuit provides pulsed or continuous low-resistance load to imitate effect of short circuit on Ni/H2 or other electrochemical power cells. Includes safety/warning feature and taps for measurement of cell-output voltage and current.

  13. Electron injection in microtron

    International Nuclear Information System (INIS)

    Axinescu, S.

    1977-01-01

    A review of the methods of injecting electrons in the microtron is presented. A special attention is paid to efficient injection systems developed by Wernholm and Kapitza. A comparison of advantages and disadvantages of both systems is made in relation to the purpose of the microtron. (author)

  14. 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.

  15. Electron Device Contact Studies.

    Science.gov (United States)

    1980-08-01

    including foreign nations. This technical report has been reviewed and is approved for publication. MILLARD C. # IyR , PrFoject Engineer Electronic...potential ED - Ec = TD = donor potential (for Sn in GaAs nD = 5.82 meV [351 Given values for Cs and T, the computer programs find the simultaneous

  16. Electronic document interchange

    Science.gov (United States)

    Erwin, Jim

    1993-01-01

    The operational impact of various storage formats related to electronic publishing of documents in the NASA Scientific and Technical Information (STI) Program is discussed. Questions are raised about the development of full text, surrogate, and hybrid storage formats. It appears that the eventual configuration will contain a mix of storage formats based on user demand.

  17. Electron beam processing system

    International Nuclear Information System (INIS)

    Kashiwagi, Masayuki

    2004-01-01

    Electron beam Processing Systems (EPS) are used as useful and powerful tools in many industrial application fields such as the production of cross-linked wire, rubber tire, heat shrinkable film and tubing, curing, degradation of polymers, sterilization and environmental application. In this paper, the feature and application fields, the selection of machine ratings and safety measures of EPS will be described. (author)

  18. Electron hopping through proteins

    Czech Academy of Sciences Publication Activity Database

    Warren, J. J.; Ener, M. E.; Vlček, Antonín; Winkler, J. R.; Gray, H. B.

    2012-01-01

    Roč. 256, 21-22 (2012), s. 2478-2487 ISSN 0010-8545 R&D Projects: GA MŠk(CZ) ME10124 Institutional support: RVO:61388955 Keywords : electron transfer * multistep tunneling * hopping maps Subject RIV: CG - Electrochemistry Impact factor: 11.016, year: 2012

  19. Basic Electronics II.

    Science.gov (United States)

    Willison, Neal A.; Shelton, James K.

    Designed for use in basic electronics programs, this curriculum guide is comprised of 15 units of instruction. Unit titles are Review of the Nature of Matter and the P-N Junction, Rectifiers, Filters, Special Semiconductor Diodes, Bipolar-Junction Diodes, Bipolar Transistor Circuits, Transistor Amplifiers, Operational Amplifiers, Logic Devices,…

  20. 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...