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Sample records for hoplias malabaricus bloch

  1. Differential chromosomal markers between sympatric karyomorphs of the fish Hoplias malabaricus (Bloch, 1794 (Characiformes: Erythrinidae

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    Renata Rosa

    2010-12-01

    Full Text Available Cytogenetic analyses were performed on Hoplias malabaricus (Bloch, 1794 from the Taquari River, Parana River drainage, revealing two sympatric karyomorphs. One karyomorph was characterized by 2n = 40 m/sm and 2n = 39 m/sm chromosomes for females and males, respectively, and an X1X1X2X2/X1X2Y sex chromosome system. In the second karyomorph, specimens showed 2n = 42 m/sm chromosomes, without sex-related heteromorphism. Both karyomorphs were characterized by a distribution of heterochromatin in the pericentromeric and telomeric regions. In addition to the differences in the diploid numbers and the sex chromosomes, the GC-rich sites and the nucleolar organizer regions also showed clear differences between the karyomorphs. Coupled with the occurrence of unique chromosomal features within each karyomorph, the fact that hybrids have not been identified in the sampled population provides additional support of the existence of a species complex in H. malabaricus.

  2. Phylogeography and RAPD-PCR variation in Hoplias malabaricus (Bloch, 1794 (Pisces, Teleostei in southeastern Brazil

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    Dergam Jorge A.

    2002-01-01

    Full Text Available In the Rio Doce basin of southeastern Brazil, the freshwater fish Hoplias malabaricus (trahira is a widespread predatory characin and one of the few resilient native fishes in a highly impacted lake system. In order to test for genetic differentiation in populations within this basin and for biogeographic relationships among populations of this species in other basins, a study was conducted using RAPD-PCR analysis of Rio Doce samples (N = 63 and phylogeographic analyses with mitochondrial DNA (mtDNA haplotypes, including the Rio Grande and Macacu river basins. In the Rio Doce basin, the patterns of genetic similarity of RAPD-PCR markers (individual fingerprinting and Nei?s genetic distance suggest the existence of two genetically different groups, one composed of the lacustrine populations Carioca and Dom Helvécio, and the other of riverine and the remaining lacustrine populations. The differences in the RAPD-PCR patterns may be explained by the existence of sub-basins within this lacustrine system. A maximum parsimony tree of cytochrome b fragment (383 base pairs supports the view that trahiras of the Rio Doce share a complex biogeographic history with those of neighboring basins. The phylogeographic patterns may be explained by a common history of the watersheds of the Rio Doce, Paraíba do Sul, and Rio Grande basins, corroborating the hypothesis of a Plio-Pleistocene separation of these drainage systems, forming the Mantiqueira "divortium aquarium".

  3. Morphometric evaluation of the spermatogenesis in trahira Hoplias malabaricus (Bloch (Characiformes, Erythrinidae Avaliação morfométrica da espermatogênese da traíra Hoplias malabaricus (Bloch (Characiformes, Erythrinidae

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    Paula M. Bizzott

    2007-01-01

    Full Text Available The Erythrinidae trahira, Hoplias malabaricus (Bloch, 1794, is widespread throughout South America river basins. We determined Sertoli cell supporting capacity (ratio of primary spermatocytes: Sertoli cells and spermatids: Sertoli cells, meiotic index (ratio of spermatids: primary spermatocytes and the number of spermatogonial mitotic generations of this fish. The fish were captured in the Igarapava reservoir, Grande River, Alto Paraná River basin, Brazil. Testis fragments of three sexually mature trahiras were fixed in 5% buffered glutaraldehyde solution and embedded in glycol methacrylate. Serial sections of 2 and 3 µm in thickness were stained with 0.5% toluidine blue. Histological counts from cysts of primary spermatocytes and spermatids revealed, respectively, 326 ± 99 and 468 ± 73 nuclei of these cells. Sertoli cell supporting capacity was considerably higher for spermatids (113.3 ± 16:1 when compared to primary spermatocytes (71 ± 5:1. Between eight and ten spermatogonial generations were formed to give rise to primary spermatocytes. These values were within the generation range of those already found in freshwater teleosts of external fertilization. Correlation between the number of Sertoli cells and primary spermatocytes per cyst, and Sertoli cells and spermatids per cyst were statistically significant (p A traíra, Hoplias malabaricus (Bloch, 1794, da família Erythrinidae, encontra-se espalhada pelas bacias fluviais da América do Sul. Determinou-se a capacidade de suporte das células de Sertoli (espermatócitos primários: células de Sertoli e espermátides: células de Sertoli, índice meiótico (espermátides: espermatócitos primário e o número de gerações mitóticas de espermatogônias desse peixe. Os indivíduos foram capturados no reservatório de Igarapava, rio Grande, bacia do Alto Paraná, Brasil. Fragmentos dos testículos de três traíras sexualmente maduras foram fixados em glutaraldeído a 5%, e inclu

  4. Feeding of Hoplias aff. malabaricus (Bloch, 1794 and Oligosarcus robustus Menezes, 1969 in a lagoon under estuarine influence, Pelotas, RS

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    Fabiano Corrêa

    2009-09-01

    Full Text Available The objective of the present paper was to study the diets of Hoplias aff. malabaricus and Oligosarcus robust in “Pequena Lagoon” and evaluate the importance of estuarine organisms in the feeding of freshwater fish. A total of twelve food categories were identified and it was established that the fish resource was the most frequent in the diet of both species. Euryhaline fish such as Mugil platanus mullets and Odontesthes argentinensis silversides were common items in the diets of these two species, which included not only freshwater fish but also euryhaline fish from the adjacent estuarine zone, integrating both resources in the food chain.

  5. Efeito dos conservantes sobre a densidade calórica em músculos de Hoplias aff. malabaricus (Bloch, 1794 (Osteichthyes, Erythrinidae Effect of preservatives on caloric density in the muscles of Hoplias aff. malabaricus (Bloch, 1794 (Osteichthyes, Erythrinidae

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    Milena Morimoto

    2002-05-01

    Full Text Available A conservação de amostras para a determinação dos valores calóricos em estudos de bioenergética de peixes tem se apresentado, na literatura, com uma variedade de métodos. Com o intuito de identificar o efeito de conservantes sobre os resultados obtidos com as diferentes técnicas de conservação, foram coletados exemplares adultos de Hoplias aff. malabaricus (Osteichthyes, Erythrinidae na planície de inundação do rio Paraná. De cada exemplar, foram retiradas 5 amostras da musculatura, as quais foram submetidas aos seguintes tratamentos: formol (4%, álcool (70%, congelamento (-10oC, nitrogênio líquido (-180oC e estufa à 60oC (amostra controle. Depois de 30 dias, todas as amostras foram secas em estufa à 60oC e posteriormente procedeu-se à determinação calórica de cada uma das amostras em bomba calorimétrica. Detectaram-se diferenças significativas entre os tratamentos (ANOVA: N=206; F=50,28; pThe preservation of samples for caloric values determination in bioenergetic studies of fish has been presented literature with a variety of methods. To identify the effect of preservatives over the results obtained with different preservation techniques, adult individuals of Hoplias aff. malabaricus (Osteichthyes, Erythrinidae were collected in Paraná river floodplain. From each fish, five samples were extracted from its dorsal muscle and submitted each sample for a different treatment: ice (-10ºC, formaldehyde (4%, alcohol (70%, liquid nitrogen (-180oC and a control sample immediately oven dried (60oC. After 30 days, the treatments were oven dried (60oC and caloric values of each sample were determined in a caloric bomb. Significant differences among the treatments were found (ANOVA: n = 206; F = 50.28; p < 0.001. Some evaluations of the effects of each treatment were presented for further comparisons with the results published in literature.

  6. Biogeography and comparative cytogenetics between two populations of Hoplias malabaricus (Bloch, 1794 (Ostariophysi: Erythrinidae from coastal basins in the State of Bahia, Brazil

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    Uedson Pereira Jacobina

    Full Text Available The species Hoplias malabaricus is a predator fish found in nearly all cis-Andean basins. From a cytogenetic point of view, this species comprises, at least, seven differentiated karyomorphs. Several localities have been formerly analyzed in Brazil, however, some regions, such as Bahia State, remain underrepresented. Recently, the Brazilian Environment Ministry classified both Itapicuru and Contas river basins (entirely located within Bahia territory as priority conservation areas, whose biodiversity status lacks enough information. Therefore, the goal of the present work was to characterize, cytogenetically, populations of H. malabaricus from both basins, by using conventional staining, Ag-NOR and C-banding techniques. All specimens presented a diploid number of 2n = 40 with metacentric/submetacentric chromosomes, without differences between sexes, thereby representing the so-called "karyomorph F". The first metacentric pair presented a remarkably larger size in relation to the other pairs. The NORs were multiple, comprising the terminal region on long arms of two chromosomal pairs in both populations. However, the C-banding pattern was somewhat distinguishable between samples. Although sharing heterochromatic blocks at centromeric region of all chromosomes, the population from Itapicuru River basin appeared to have some more conspicuous blocks than those observed in the population from Contas River basin. The similar karyotype observed in both populations suggests a common geological history between them. The present results represent an advance in the knowledge about the cytogenetic pattern of H. malabaricus populations from poorly studied basins.

  7. Avaliação de metazoarios parasitos de Hoplias malabaricus (Bloch, 1794) (Pisces: Erythrinidae) como potenciais indicadores de qualidade ambiental

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    Lincoln Lima Correa

    2009-01-01

    Resumo: Este estudo teve como objetivo a associação entre os índices hematológicos de Hoplias malabaricus (traíra), o parasitismo por monogeneas e outras espécies de metazoários e os fatores ambientais. O estudo ocorreu nas lagoas do CEPTA/ICMBio, localizada no município de Pirassununga, SP (21º55'55"S e 47º22'37"W), no período de fevereiro de 2008 a março de 2009 em 187 traíras. Verificou-se que os parâmetros sanguíneos não sofreram alterações significativas em relação ao estágio de maturaçã...

  8. Reproductive dynamics and population structure of Hoplias aff. malabaricus (Bloch, 1794 (Characiformes, Erythrinidae in the dam lake of the Taperoá River Basin, Paraíba

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    Maria Cristina Crispim

    2009-06-01

    Full Text Available This work aims to verify the reproductive dynamics and growth of the Hoplias aff. malabaricus species in the Taperoá II dam lake (07º11’44”S, 07º13’44”S, located in the basin of the River Taperoá in the Cariri region of Paraiba. Sixty-seven individuals were collected (August-December 2002, January-February, May and June 2003 by means of gillnets and cast nets. The interference of the rain regimen in the reproductive behavior and the structure of growth of the species were observed after the macrocospic analysis of the gonads of the collected units.

  9. Primeiro relato de larvas de Eustrongylides sp. (Nematoda: Dioctophymatidae) em Hoplias malabaricus (Characiformes: Erythrinidae) no Estado de Rondônia, Amazônia Ocidental, Brasil

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    Meneguetti, Dionatas Ulisses de Oliveira; Laray, Marcos Paulo de Oliveira; Camargo, Luís Marcelo Aranha

    2013-01-01

    O presente artigo descreve o primeiro relato de larvas de Eustrongylides sp. em Hoplias malabaricus Bloch, 1794 (Characiformes: Erythrinidae) no Estado de Rondônia, Amazônia Ocidental, Brasil, sendo mais um parasita com a possibilidade de contaminar humanos no Estado.

  10. Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes

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    M. R. Aquino-Silva

    Full Text Available Kinetic properties and thermal stabilities of Hoplias malabaricus liver and skeletal muscle unfractionated malate dehydrogenase (MDH, EC 1.1.1.37 and its isolated isoforms were analyzed to further study the possible sMDH-A* locus duplication evolved from a recent tandem duplication. Both A (A1 and A2 and B isoforms had similar optima pH (7.5-8.0. While Hoplias A isoform could not be characterized as thermostable, B could as thermolabile. A isoforms differed from B isoform in having higher Km values for oxaloacetate. The possibly duplicated A2 isoform showed higher substrate affinity than the A1. Hoplias duplicated A isoforms may influence the direction of carbon flow between glycolisis and gluconeogenesis.

  11. Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes

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    Aquino-Silva M. R.

    2003-01-01

    Full Text Available Kinetic properties and thermal stabilities of Hoplias malabaricus liver and skeletal muscle unfractionated malate dehydrogenase (MDH, EC 1.1.1.37 and its isolated isoforms were analyzed to further study the possible sMDH-A* locus duplication evolved from a recent tandem duplication. Both A (A1 and A2 and B isoforms had similar optima pH (7.5-8.0. While Hoplias A isoform could not be characterized as thermostable, B could as thermolabile. A isoforms differed from B isoform in having higher Km values for oxaloacetate. The possibly duplicated A2 isoform showed higher substrate affinity than the A1. Hoplias duplicated A isoforms may influence the direction of carbon flow between glycolisis and gluconeogenesis.

  12. A new sympatric region for distinct karyotypic forms of Hoplias malabaricus (Pisces, Erythrinidae

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    G. G. Born

    Full Text Available Specimens of Hoplias malabaricus from Lagoa Carioca, an isolated lake of the Rio Doce State Park (state of Minas Gerais, Brazil, were cytogenetically studied. The diploid number was found to be constant, i.e., 2n = 42 chromosomes, although two karyotypic forms were found: karyotype A, characterized by 22M + 20SM chromosomes, observed only in a male specimen, and karyotype B, characterized by 24M + 16SM + 2ST and 24M + 17SM + 1ST chromosomes in female and male specimens, respectively. This sex difference found in karyotype B is related to an XX/XY sex chromosome system. Another female specimen of H. malabaricus, also carrying karyotype A, had previously been found in the same lake. The available data indicate that two sympatric cytotypes of H. malabaricus exist in the Lagoa Carioca, with cytotype A occurring at a lower frequency and differing from cytotype B by undifferentiated sex chromosomes.

  13. Ureotelism is inducible in the neotropical freshwater Hoplias malabaricus (Teleostei, Erythrinidae

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    G. Moraes

    Full Text Available Increased environmental pH decreases ammonia transport through the gills, impairing nitrogenous waste. The consequent toxicity is usually drastic to most fishes. A few species are able to synthesize urea as a way to detoxify plasma ammonia. We studied three teleosts of the family Erythrinidae living in distinct environments, and assumed the biochemical behaviors would be different in spite of their being closely related species. Adult fish collected in the wild were submitted to alkaline water and the urea excretion rate was determined. The specific activity of urea cycle enzymes was determined in liver samples of fish from neutral waters. The studied species Hoplias lacerdae, Hoplerithrynus unitaeniatus, and Hoplias malabaricus are ureogenic. Urea synthesis is not a metabolic way to detoxify ammonia in H. lacerdae and Hoplerithrynus unitaeniatus exposed to an alkaline environment. The plasma ammonia profile of both species showed two distinct biochemical responses. Urea excretion of H. malabaricus was high in alkaline water, and the transition to ureotelism is proposed. The nitrogen excretion rate of H. malabaricus was among the highest values reported and the high urea excretion leads us to include this species as ureotelic in alkaline water.

  14. Tooth morphology, implantation and replacement system of Hoplias malabaricus (Teleostei, Characiformes, Erythrinidae

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    RM. Hassunuma

    Full Text Available The oropharyngeal cavity of Hoplias malabaricus, an ichthyophagous freshwater fish, is anatomically adapted to predation. Macroscopic and microscopic analyses were conducted in order to study the morphology and system of implantation and replacement of teeth. The results showed that this teleost has conical and caniniform teeth, with an orthodentin crown covered by an enameloid cap and a vascularised orthodentin in the root. With regard to the implantation system, there is a junction between the tooth and the bone tissue, as a typical physiological dental ankylosis. The teeth are replaced by a resorption process of multinucleated giant cells that actively eliminate the dentin and bone tissue.

  15. CRECIMIENTO Y MORTALIDAD DEL MONCHOLO (Hoplias malabaricus EN LA CIÉNAGA GRANDE DE LORICA, COLOMBIA

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    Glenys Tordecilla-Petro,

    2005-12-01

    Full Text Available Para estimar los parámetros de crecimiento y mortalidad del moncholo (Hoplias malabaricus Bloch 1794en la Ciénaga Grande de Lorica (CGL se aplicó el análisis de frecuencia de tallas (ELEFAN a la informacióncolectada entre enero y diciembre 2000. Los valores estimados para L¥, K y t0 fueron 48.1 (± 0.09 cm.,0.29 (+ 0.01 año-1 y -0.50 años, respectivamente, con temperatura media anual de 28 °C y límites deconfianza del 95%. Las estimaciones para L¥ y K indican que es un pez de longevidad y tasa de crecimientomedios. La mortalidad total (Z fue estimada en 2.31 (± 0.23 año-1, la mortalidad natural (M en 0.70año–1, la mortalidad por captura (F se calculó en 1.61 año –1, y la tasa de explotación (E=F/Z 0.70. Latalla de su primera captura (Lc es de 29.4 cm., LT, y su talla media de captura (TMC es de 30.0 cm., LT.Como la especie no presenta migración reproductiva, permanece en la CGL, siendo capturada en laausencia de las especies reofílicas tradicionalmente capturadas, la presión pesquera aumenta sobre ella,alcanzando niveles de sobrepesca. La construcción y operación de la hidroeléctrica Urrá (HU y lacontaminación orgánica e inorgánica durante el año 2000 afectaron la dinámica poblacional de los pecesde la Cuenca del río Sinú, por lo que es necesario que se agilice el ordenamiento de su pesquería en elmediano plazo considerando que el moncholo es la tercera especie en la composición de la captura en lacuenca.

  16. Cytogenetics and biogeography: considerations about the natural origin of Hoplias malabaricus (Characiformes, Erythrinidae on the Iguaçu river

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    Vicari Marcelo Ricardo

    2006-01-01

    Full Text Available Hoplias malabaricus (trahyra is a widespread fish species over the Neotropical region with diversified inter-populational karyotypes (cytotypes, which may correspond to a species complex. Despite the wide distribution in the South American basins, some authors have questioned its natural origin in the Iguaçu river, an important Brazilian river basin which is characterized by several endemic fish species. We have analyzed the karyotype of H. malabaricus from different collection sites of this river, by conventional and banding methods. Our results, in addition to our previous data concerning geographic distribution of the cytotypes, contribute to better understand the origin of H. malabaricus on the Iguaçu river, reinforcing the proposition that it is a natural fish species in this river basin.

  17. Cytogenetic and DNA barcoding reveals high divergence within the trahira, Hoplias malabaricus (Characiformes: Erythrinidae from the lower Amazon River

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    Diego Ferreira Marques

    Full Text Available Molecular and cytogenetic data have provided evidence of cryptic speciation in the widespread South American trahira, Hoplias malabaricus. In the present study, karyotypes and DNA barcode sequences of specimens from seven populations inhabiting the lower Amazon River were analyzed in order to characterize the levels of genetic divergence within a single karyomorph. All the specimens presented karyotypes with 2n = 40 chromosomes (20m+20sm that were consistent with the species' C karyomorph. The DNA barcodes revealed six haplogroups, with clear divergence between populations from Brazil and Argentina. The results support the species complex hypothesis and indicate that a single karyomorph of H. malabaricus may harbor more than one species

  18. Pola Resistensi Salmonella typhi yang Diisolasi dari Ikan Serigala (Hoplias malabaricus terhadap Antibiotik

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    Waode Santa Monica

    2013-11-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE The purpose of this study was to know the resistant pattern of Salmonella typhi (S. typhi isolated from wolf fish (Hoplias malabaricus to antibiotics in Bali Safari and Marine Park. S. typhi was isolated from fecal swab collected from the illness fish. The S. typhi was confirmed with MicrogenTM GN A ID test’s method. The antibiotic sensitivity of the S. typhi was tested using streptomycin, gentamicin, penicillin, vancomycin, and chloramphenicol according to the Kirby bouer method. The results showed that the isolate of S. typhi was resistant to penicillin and vancomycin, but sensitive to streptomycin, gentamicin, and chloramphenicol. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; text-align:justify; line-height:150%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

  19. Amino acids and carbohydrates absorption by Na+-dependent transporters in the pyloric ceca of Hoplias malabaricus (Erythrinidae

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    Vieira Vania Lucia Pimentel

    2001-01-01

    Full Text Available Information about amino acids and carbohydrate absorption in fish is important to formulate an adequate diet to obtain optimal growth. Therefore, the objective of this study was to investigate if Na+-dependent transporters are involved on the absorption of glycine, L-glutamine, L-leucine, L-lysine, L-proline, L-alanine, and the carbohydrates fructose and glucose in the pyloric ceca of Hoplias malabaricus. The pyloric ceca were mounted in a system of continuous perfusion "in vitro". Amino acids and carbohydrates were placed on the mucosal side at concentrations of 10, 20, and 40mM. The serosal side of the pyloric ceca was positive in relation to the mucosal side. The addition of glycine, L-glutamine, L-leucine, L-lysine, L-proline (all tested concentrations, and glucose (at concentrations of 20 and 40mM increased the positivity of the serosal side, indicating the presence of Na+-dependent transporters in the absorption of these substances. L-alanine and fructose did not change the positivity of the serosal side. The pyloric ceca seem to be the main site of nutrient absorption in the digestive tract of H. malabaricus.

  20. Blood parameter analysis and morphological alterations as biomarkers on the health of Hoplias malabaricus and Geophagus brasiliensis

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    Silvia Romão

    2006-05-01

    Full Text Available This study aimed to assess the influence of the environment on fish health. Samples of Hoplias malabaricus and Geophagus brasiliensis, were collected from three different environments: area I was urban and areas II and III were rural. Analyses of red blood cell count, microhematocrit, hemoglobin concentration, white blood cell count and differential white cell count in blood smear were carried out. Mean corpuscular volume and mean corpuscular hemoglobin concentration were calculated. To analyze morphological alterations, gills, liver, kidney and gonads were submitted to routine histological processing. Individuals collected from area III had slightly lower blood indices than collected from area I . Severe kidney changes, degeneration of and crystallization within kidney tubules were observed. In area I, crystallization was observed in 92% of the specimens of G. brasiliensis. These results suggested that such alterations were related with poor water circulation in the place.Este trabalho teve como objetivo avaliar a influência do ambiente sobre a higidez dos peixes. Animais, das espécies Hoplias malabaricus e Geophagus brasiliensis foram coletados em três ambientes distintos, sendo ambiente I região urbana e ambientes II e III em região rural. Foram realizadas análises do número total de eritrócitos por microlitro de sangue, microhematócrito, taxa de hemoglobina, porcentagem de leucócito e contagem diferencial de leucócitos em extensão sanguínea. Calcularam-se os índices hematimétricos absolutos: volume corpuscular médio e concentração de hemoglobina corpuscular média. Para análises das alterações morfológicas, brânquias, fígado, gônadas e rim seguiram processamento histológico de rotina. Foram observados índices hematológicos ligeiramente menores em indivíduos coletados no ambiente III em relação aos animais coletados no ambiente I. As análises histológicas de brânquias, fígado e gônadas das espécies G

  1. Genetic damage induced by trophic doses of lead in the neotropical fish Hoplias malabaricus (Characiformes, Erythrinidae as revealed by the comet assay and chromosomal aberrations

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    Marta Margarete Cestari

    2004-01-01

    Full Text Available The effects of clastogenic or mutagenic agents have rarely been studied in neotropical fish species exposed to contaminated water. In this study, the genetic damage caused by lead in the widely distributed South American fish, Hoplias malabaricus, was assessed using the comet (SCGE assay and by testing for chromosomal aberrations. Eighteen specimens were acclimatized to laboratory conditions and then chronically exposed to contaminated food by feeding prey (Cyprinus sp. injected intraperitoneally with doses of inorganic lead adjusted to give a contamination level of 21 mg of Pb2+.g-1 net weight of H. malabaricus. Three fish were sampled for chromosomal analysis after four doses (18 days and another three after eight doses (41 days of lead and the results then compared with three untreated controls kept under lead-free conditions. An additional six treated fish and three controls were sampled for the comet assay after 13 doses (64 days. Exposure to lead significantly increased the frequency of chromosomal aberrations and the frequency of tailed cell nuclei, the latter indicating DNA damage. These results show that H. malabaricus is a useful biological model for screening the clastogenic effects of lead and possibly other xenobiotics. The genetic damage seen here illustrates the need to investigate the potential effects of heavy metals on fish species in South America.

  2. Hematological and histopathological changes in Hoplias malabaricus from the São Francisco River, Brazil caused by larvae of Contracaecum sp. (Nematoda, Anisakidae

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    Corrêa L. L.

    2015-06-01

    Full Text Available Until now studies in Brazil of the pathological action of Contracaecum sp. larvae in Hoplias malabaricus have been rare. The aim of the present study was to analyze and describe histopathological changes in the stomach of H. malabaricus caused by different intensities of infection by larvae of Contracaecum sp., and the hematological effects of such infection. The mean intensity of infection by L3 larvae of Contracaecum sp. correlated positively with Hematocrit percentage (Hct% and correlated negatively with mean corpuscular volume (MCV. These findings are possibly related to the passage of larvae from the stomach to the mesentery, potentially due to hemorrhaging t. Fish with high infection intensity had larvae of Contracaecum sp in the submucosal of the stomach, which caused destruction of Type I and Type III collagen (finer and more delicate collagen fibers which do not form beams and are permeated by fundamental substances around the parasite. Microscopic analysis showed that crypts were arranged regularly throughout the stomach mucosal, varying in number, size and depth, depending on the region of the stomach.

  3. Population structure and stock assessment of Hoplias malabaricus (Characiformes: Erythrinidae caught by artisanal fishermen in river-reservoir transition area in Brazil

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    José Luís Costa Novaes

    2011-03-01

    Full Text Available Hoplias malabaricus is a viable economic alternative for artisanal fishermen who used to live on the banks of rivers that now are dammed in Brazil. In order to preserve the species’ natural stock, the main objectives of this study were to obtain bio-ecological information on this species reproduction, feeding dynamics and the description of the extent of its exploitation in river-reservoir transition area in Brazil. This way, from January to December 2005, different fishery catches were made with gill nets by artisanal fishermen, and a total of 426 individual H. malabaricus were obtained and sampled. From each specimen, the following biometric and biological data were analyzed: standard length, total weight, stomach contents, reproductive data such as sex, weight and gonadal maturation stage; with these data we estimated sex ratio, reproduction period and feeding habits. To assess growth parameters and infer on the degree of exploitation, the standard length frequency data were analysed using the FISAT (ELEFAN I computer program. Data revealed a sex ratio of 0.8:1 (M:F, that reproduction occurs all year around, being more intense during spring and summer; it also showed that H. malabaricus is piscivorous. The growth parameters and mortality were estimated at: L∞=35.18cm, k=0.32 year, longevity=9.3 years, Z=1.25 years, M=0.63 year and F=0.62 year. The weight-length relationship was: ln Wt=-3.1663+2.7456 ln Lp. The yield-per-recruit analysis produced the following values: E=0.496, Emax=0.916, E0.1=0.701 and E0.5=0.378. Overall, our data suggest that the stock of H. malabaricus is not yet overfished in the studied area. Rev. Biol. Trop. 59 (1: 71-83. Epub 2011 March 01.Hoplias malabaricus representa una alternativa económica viable para los pescadores artesanales que viven a la orilla de ríos que actualmente cuentan con represas en Brasil. El objeto del presente estudio fue evaluar la dinámica de la reproducción, alimentación, crecimiento

  4. Molecular biogeography of the Neotropical fish Hoplias malabaricus (Erythrinidae:Characiformes in the Iguaçu, Tibagi, and Paraná Rivers

    Directory of Open Access Journals (Sweden)

    Jorge A. Dergam

    1998-12-01

    Full Text Available Hoplias malabaricus, the common trahira, extended its range into the Iguaçu River sometime in the last decades. To determine levels of genetic differentiation in neighboring basins of this nominal taxon, as well as to unveil the source of the invading population, we analyzed patterns of similarity of RAPD-PCR genomic markers of samples from Paraná, Iguaçu and Tibagi Rivers. The high genetic diversity of samples from the Paraná and Tibagi Rivers suggested strong population structuring or even the occurrence of undescribed species. All alleles of the sample from the headwaters of Tibagi River were present in the sample from the Iguaçu River, which suggests that the former population or another population with similar genetic makeup, may be the source of the trahiras of the Iguaçu River.Hoplias malabaricus, a traíra, colonizou o Rio Iguaçu nas últimas décadas. Numa tentativa de determinar os níveis de diferenciação genética deste taxon nominal em bacias vizinhas, assim como a origem da população colonizadora, foram analisados os padrões de similaridade de marcadores genômicos do tipo randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR de amostras dos rios Paraná, Iguaçu, e Tibagi. As amostras do Paraná e do Tibagi apresentaram elevados índices de diversidade genética, os quais sugerem a ocorrência de espécies diferentes nestes rios. Todos os alelos presentes na população da cabeceira do rio Tibagi ocorreram também na amostra do rio Iguaçu. Esta semelhança permite-nos sugerir que a população da cabeceira do rio Tibagi (ou alguma população com características genéticas semelhantes possa ser a origem da população amostrada no rio Iguaçu.

  5. Efeito dos conservantes sobre a densidade calórica em músculos de Hoplias aff. malabaricus (Bloch, 1794) (Osteichthyes, Erythrinidae) Effect of preservatives on caloric density in the muscles of Hoplias aff. malabaricus (Bloch, 1794) (Osteichthyes, Erythrinidae)

    National Research Council Canada - National Science Library

    Milena Morimoto; Evanilde Benedito-Cecilio

    2002-01-01

    ... bioenergética de peixes tem se apresentado, na literatura, com uma variedade de métodos. Com o intuito de identificar o efeito de conservantes sobre os resultados obtidos com as diferentes técnicas de...

  6. Feeding and morphological analysis of the digestive tract of four species of fish (Astyanax altiparanae, Parauchenipterus galeatus, Serrasalmus marginatus and Hoplias aff. malabaricus from the upper Paraná River floodplain, Brazil

    Directory of Open Access Journals (Sweden)

    D. Peretti

    Full Text Available The present study is inspired by the great wealth of species exhibited by the ichthiofauna. Not only concepts and techniques of ecology deserve attention, but also knowledge in other biological areas, such as zoology and anatomy, are necessary. The intention of the present work is to discover the morphology of fish through the study of the digestive tract morphology, associating it to diet data, in order to better understand the biology of four fish species of the upper Paraná River floodplain. The samples were collected quarterly in the year 2000 with gillnets of different meshes. The stomach content was analyzed under a stereoscopic microscope and the frequencies of occurrence (FO and volumetric (FV and the alimentary index (IAi were calculated. Various morphologic characteristics were analyzed and schematized using a light chamber. The species were grouped into two trophic guilds - insectivores (Astyanax altiparanae and Parauchenipterus galeatus and piscivores (Serrasalmus marginatus and Hoplias aff. malabaricus. The first two, although consumers of insects, preyed on different alimentary groups, notably Hymenoptera in the case of A. altiparanae and Coleoptera in the case of P. galeatus. Serrasalmus marginatus and H. aff. malabaricus consumed mainly fishes. However, only pieces of prey were usually found in the stomach content of the first species, whereas whole fishes were found in the stomach content of the second. Astyanax altiparanae exhibited characteristics that allowed it to obtain food in several compartments of the water column. Similarly P. galeatus consumed food resources that were available in all aquatic compartments, although the abilities to capture, to manipulate and to absorb food differed, as shown by the importance of teeth plates and pharyngeal teeth. Serrasalmus marginatus and H. aff. malabaricus, although resembling each other in many aspects of the digestive tract morphology, differed in the strategies used to capture

  7. The effects of temperature on gastric emptying time of malabar blood snapper (Lutjanus malabaricus, Bloch & Schneider 1801) using X-radiography technique

    Science.gov (United States)

    Mazumder, Sabuj Kanti; Ghaffar, Mazlan Abd.; Das, Simon Kumar

    2015-09-01

    Water temperature can influence the metabolic rate of ectothermal animal such as, fish. This study aims to investigate the gastric emptying time (GET) of malabar blood snapper (L. malabaricus) at different temperature (22, 26, 30, 34°C) fed with commercial diet pellet. The gastric emptying times at different temperatures were determined X-radiographically, using barium sulfate (BaSO4) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-8 h after feeding at all temperature. The fastest GET (18 h) was obsereved at 30°C, whereas the longest (28 h) GET was seen at 22°C. GET was increased with increasing temperature up to 30°C whereas decreased at extreme (34°C) and stress temperature (22°C). The findings of this study suggest to culture L. malabaricus at 26-30°C with commercial diet pellet as this temperature ranges escalate the faster digestion process which may contribute faster growth rate of this commercially important fish species. Overall, the data obtained from this study may have important consequences for optimization of commercial production of malabar blood snapper.

  8. The effects of temperature on gastric emptying time of malabar blood snapper (Lutjanus malabaricus, Bloch & Schneider 1801) using X-radiography technique

    Energy Technology Data Exchange (ETDEWEB)

    Mazumder, Sabuj Kanti, E-mail: sabujsau@gmail.com [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Ghaffar, Mazlan Abd., E-mail: magfish05@yahoo.com [Marine Ecosystem Research Centre (EKOMAR), Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Institute of Tropical Aquaculture, University of Malaysia Terengganu, 21030 Kuala Terengganu (Malaysia); Das, Simon Kumar, E-mail: skdas-maa@yahoo.com [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Marine Ecosystem Research Centre (EKOMAR), Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-09-25

    Water temperature can influence the metabolic rate of ectothermal animal such as, fish. This study aims to investigate the gastric emptying time (GET) of malabar blood snapper (L. malabaricus) at different temperature (22, 26, 30, 34°C) fed with commercial diet pellet. The gastric emptying times at different temperatures were determined X-radiographically, using barium sulfate (BaSO{sub 4}) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-8 h after feeding at all temperature. The fastest GET (18 h) was obsereved at 30°C, whereas the longest (28 h) GET was seen at 22°C. GET was increased with increasing temperature up to 30°C whereas decreased at extreme (34°C) and stress temperature (22°C). The findings of this study suggest to culture L. malabaricus at 26-30°C with commercial diet pellet as this temperature ranges escalate the faster digestion process which may contribute faster growth rate of this commercially important fish species. Overall, the data obtained from this study may have important consequences for optimization of commercial production of malabar blood snapper.

  9. Efeitos ecotoxicológicos das saxitoxinas em Hoplias malabaricus

    OpenAIRE

    Silva, Cesar Aparecido da

    2012-01-01

    Resumo: Floracoes de cianobacterias podutoras de saxitoxinas (STXs), como a Cylindrospermopsis raciborskii, tem se tornado um grave problema ambiental, especialmente no sul do Brasil, onde a especie ja e dominante em reservatorio de abastecimento publico. As STXs sao neurotoxinas que atuam bloquendo os canais de sodio (Na+) dos neuronios, o que pode levar a morte por parada respiratoria. Entretanto, a bioacumulacao deste tipo de substancia na cadeia trofica e seus efeitos ecotoxicologicos, pr...

  10. Marc bloch

    OpenAIRE

    Restrepo A., Luis Antonio

    2011-01-01

    Lucien Fevre (1878-1956) y Marc Bloch ( 1866-1944), se conocieron cuando fueron profesores de la Universidad de Estrasburgo, mientras escribían y publicaban algunos de sus primeros grandes libros, por ejemplo, Los reyes taumaturgos de Bloch en 1924, Martin Lutero.

  11. Mutagenic effects of tributyltin and inorganic lead (Pb II on the fish H. malabaricus as evaluated using the comet assay and the piscine micronucleus and chromosome aberration tests

    Directory of Open Access Journals (Sweden)

    Marcos Vinícius M. Ferraro

    2004-01-01

    Full Text Available Genotoxicity studies on toxic metals and their organic compounds are very important, especially so in the investigation of the effects of these compounds on the aquatic environments where they tend to accumulate. The use of endemic aquatic organisms as biological sentinels has proved useful to environmental monitoring. We assessed the mutagenic potential of tributyltin (TBT and inorganic lead (PbII using samples of the fish Hoplias malabaricus (commonly called traíra using the comet assay and the piscine micronucleus and chromosome aberration tests. Eighteen H. malabaricus were acclimatized in three individual aquariums, each containing six fish, six fish being exposed to 0.3 mg/g of body weight (bw of TBT, six to 21 mg/g bw of PbII and six being used as controls. Exposure to TBT and PbII was achieved by feeding the fish every five days with Astyanax (a small fish that is part of the normal diet of H. malabaricus which had been injected with solutions of TBT, PbII or with water (the control group. After two months the H. malabaricus were sacrificed and their peripheral blood collected and subjected to the comet and micronucleus assays, the chromosome aberration assay being conducted using kidney-tissue. Although the comet assay showed now mutagenic effects at the lead concentrations used but encountered results with TBT, the micronucleus and chromosome aberrations assays both indicated that TBT and PbII are potentially mutagenic (p < 0.01, the micronucleus assay showing morphological alterations of the nucleus.

  12. Bloch — Sulzberger syndrome

    Directory of Open Access Journals (Sweden)

    Slesarenko N.A.

    2015-09-01

    Full Text Available Five clinical observations in pediatric patients with Bloch — Sulzberger syndrome are presented. The observation had been performed for six months. The differential diagnosis depending on the stage of the disease was done. The article contains variants of treating patients of this category.

  13. Botanical Knowledge in Early Modern Malabar and the Netherlands : A Review of Van Reede's Hortus Malabaricus

    NARCIS (Netherlands)

    Singh, Anjana

    2015-01-01

    This essay is a case study about information gathering and knowledge production in early modern Malabar and the Netherlands with the aim to review the historiography about the making of the Hortus Malabaricus. It focuses on the making of the twelve volumes of the Hortus Malabaricus and analyses the

  14. A theory of generalized Bloch oscillations

    DEFF Research Database (Denmark)

    Duggen, Lars; Lew Yan Voon, L. C.; Lassen, Benny

    2016-01-01

    Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact cal...... oscillations. We stipulate that the presented theory of generalized Bloch oscillations can be extended to other systems such as acoustics and photonics.......Bloch oscillations of electrons are shown to occur for cases when the energy spectrum does not consist of the traditional evenly-spaced ladders and the potential gradient does not result from an external electric field. A theory of such generalized Bloch oscillations is presented and an exact...... calculation is given to confirm this phenomenon. Our results allow for a greater freedom of design for experimentally observing Bloch oscillations. For strongly coupled oscillator systems displaying Bloch oscillations, it is further demonstrated that reordering of oscillators leads to destruction of Bloch...

  15. Marc Bloch y el compromiso del intelectual

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Aguirre Rojas

    2004-07-01

    Full Text Available Herewith is discussed Marc Bloch's work as well as his political engagement by presenting his intellectual formation and his contribution to 20 th Century historiography. We enhance the genesis of Bloch's historical work by his approach to Emile Durkheim's and Henri Berr's thought. It is also analysed Bloch's resistance against Nazism and his brutal assassination.

  16. Felix Bloch (1905–1983)

    Indian Academy of Sciences (India)

    IAS Admin

    His doctoral thesis (1928) established the quantum theory of solids, using Bloch waves. Soon after, with Grueneisen, he gave the first comprehensive theory of the temperature dependent resistivity of metals, deriving a formula named after both of them. The transition separating two magnetic domains with different ...

  17. Possible uses of the layered structure found in the scales of Hoplia coerulea (Coleoptera)

    Science.gov (United States)

    Vigneron, Jean-Pol; Rassart, Marie; Simonis, Priscilla; Colomer, Jean-Francois; Bay, Annick

    2009-08-01

    The male of the beetle Hoplia coerulea is known for its spectacular blue-violet iridescence. The blue coloration is caused by the presence of an interesting photonic structure inside the scales which cover the dorsal parts of the insect's body. This structure can be described as the stacking of chitin plates supporting arrays of parallel rods. The change of colour of this structure with humidity is investigated, as well as its response to some other external conditions, such as mechanical strain.

  18. First Bloch eigenvalue in high contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Briane, Marc, E-mail: mbriane@insa-rennes.fr [Institut de Recherche Mathématique de Rennes, INSA de Rennes (France); Vanninathan, Muthusamy, E-mail: vanni@math.tifrbng.res.in [TIFR-CAM, Bangalore (India)

    2014-01-15

    This paper deals with the asymptotic behavior of the first Bloch eigenvalue in a heterogeneous medium with a high contrast εY-periodic conductivity. When the conductivity is bounded in L{sup 1} and the constant of the Poincaré-Wirtinger weighted by the conductivity is very small with respect to ε{sup −2}, the first Bloch eigenvalue converges as ε → 0 to a limit which preserves the second-order expansion with respect to the Bloch parameter. In dimension two the expansion of the limit can be improved until the fourth-order under the same hypotheses. On the contrary, in dimension three a fibers reinforced medium combined with a L{sup 1}-unbounded conductivity leads us to a discontinuity of the limit first Bloch eigenvalue as the Bloch parameter tends to zero but remains not orthogonal to the direction of the fibers. Therefore, the high contrast conductivity of the microstructure induces an anomalous effect, since for a given low-contrast conductivity the first Bloch eigenvalue is known to be analytic with respect to the Bloch parameter around zero.

  19. A New Essential Norm Estimate of Composition Operators from Weighted Bloch Space into -Bloch Spaces

    Directory of Open Access Journals (Sweden)

    René E. Castillo

    2013-01-01

    Full Text Available Let be any weight function defined on the unit disk and let be an analytic self-map of . In the present paper, we show that the essential norm of composition operator mapping from the weighted Bloch space to -Bloch space is comparable to where for ,   is a certain special function in the weighted Bloch space. As a consequence of our estimate, we extend the results about the compactness of composition operators due to Tjani (2003.

  20. Claude Bloch scientific works, oeuvre scientifique

    CERN Document Server

    Bloch, Claude; De Dominicis, Cyrano; Gillet, Vincent; Messiah, Albert

    1975-01-01

    Claude Bloch: Scientific Works Oeuvre Scientifique covers the collection of scientific works of Claude Bloch. The book includes topics on field theories with non-localized interaction and notes on the symmetry properties of nuclear wave functions. It also covers theory of nuclear level density; the theory of imperfect fermi gases; the structure of nuclear matter; and the canonical form of an antisymmetric tensor and its application to the theory of superconductivity.

  1. Scale coloration change following water absorption in the beetle Hoplia coerulea (Coleoptera)

    Science.gov (United States)

    Rassart, Marie; Simonis, Priscilla; Bay, Annick; Deparis, Olivier; Vigneron, Jean Pol

    2009-09-01

    The blue scales on the cuticle of the male beetle Hoplia coerulea can absorb water, with the consequence that these scales, which have been shown to be responsible for the beetle’s bright blue coloration, reversibly turn to emerald green with increasing water contents. Optical measurements are shown, by analytic photonic-crystal models, to be compatible with the full filling of the scales structures with water. The natural mechanism shows the way to produce a very efficient hygrochromic material: a medium which significantly changes color when its water contents are modified.

  2. The Ising-Bloch transition in degenerate optical parametric oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Arjona, Isabel [Departament d' Optica, Universitat de Valencia, Dr Moliner 50, 46100 Burjassot (Spain); Silva, Fernando [Departament d' Optica, Universitat de Valencia, Dr Moliner 50, 46100 Burjassot (Spain); Valcarcel, German J de [Departament d' Optica, Universitat de Valencia, Dr Moliner 50, 46100 Burjassot (Spain); Roldan, Eugenio [Departament d' Optica, Universitat de Valencia, Dr Moliner 50, 46100 Burjassot (Spain); Sanchez-Morcillo, VIctor J [Departament de FIsica Aplicada, Universitat Politecnica de Valencia, Carretera Nazaret-Oliva S/N, 46730 Grao de Gandia (Spain)

    2004-05-01

    Domain walls in type I degenerate optical parametric oscillators are numerically investigated. Both steady Ising and moving Bloch walls are found, bifurcating one into another through a nonequilibrium Ising-Bloch transition. Bloch walls are found that connect either homogeneous or roll planforms. Secondary bifurcations affecting Bloch wall movement are characterized that lead to a transition from a steady drift state to a temporal chaotic movement as the system is moved far from the primary Ising-Bloch bifurcation. Two kinds of routes to chaos are found, both involving tori: the usual Ruelle-Takens and an intermittent scenario.

  3. Bloch-Messiah theorem at finite temperature

    Science.gov (United States)

    Tanabe, K.; Sugawara-Tanabe, K.

    1991-03-01

    The Bloch-Messiah theorem is extended to the thermal Hartree-Fock-Bogoliubov (THFB) theory by making use of the thermo field dynamics. This enables us to define the correct order parameter describing the superconducting phase at finite temperature, and demonstrates consistency of the THFB formalism.

  4. Quantum state transfer via Bloch oscillations

    Science.gov (United States)

    Tamascelli, Dario; Olivares, Stefano; Rossotti, Stefano; Osellame, Roberto; Paris, Matteo G. A.

    2016-01-01

    The realization of reliable quantum channels, able to transfer a quantum state with high fidelity, is a fundamental step in the construction of scalable quantum devices. In this paper we describe a transmission scheme based on the genuinely quantum effect known as Bloch oscillations. The proposed protocol makes it possible to carry a quantum state over different distances with a minimal engineering of the transmission medium and can be implemented and verified on current quantum technology hardware. PMID:27189630

  5. Taking a peek at Bloch oscillations

    Science.gov (United States)

    Morsch, Oliver

    2016-11-01

    Bloch oscillations arise when matter waves inside a periodic potential, such as a crystal lattice, are accelerated by a constant force. Keßler et al (2016 New J. Phys. 18 102001) have now experimentally tested a method that allows one to observe those oscillations continuously, without a destructive measurement on the matter wave. Their approach could help to make cold atom-based accelerometers and gravimeters more precise.

  6. On Rabi oscillations between Bloch bands

    OpenAIRE

    Plötz, Patrick

    2010-01-01

    We study Rabi oscillations between the bands of an arbitrary biased superlattice in a tight-binding model. We reduce the problem to an equation of Whittaker--Hill type and, in absence of any known solutions in closed form, discuss different approximations to describe the oscillations between the Bloch bands. We identify regimes of weak and strong inter-band coupling and compare predictions for these Rabi oscillations to numerical results.

  7. Theory of Magnetization in Bloch Electron Systems

    Science.gov (United States)

    Ogata, Masao

    2017-04-01

    The exact formulas for magnetization and magnetic susceptibility are derived for Bloch electrons in terms of Bloch wave functions. They are extensions of the previous work to general cases where the spin-orbit interaction as well as the Zeeman term is included, the potential is noncentrosymmetric, and the time-reversal symmetry is broken. The obtained magnetization for Bloch electrons is a natural generalization of the free-electron magnetic moment including the effect of the spin-orbit interaction. The obtained susceptibility has six contributions and the physical meaning of each term is clarified. The new formula contains the Landau-Peierls, Pauli, and Van Vleck susceptibilities, the atomic diamagnetism, and contributions from the "Berry curvature". In the atomic limit, the obtained formula reduces to two contributions: the atomic diamagnetism and a generalized form of the Van Vleck susceptibility modified by the spin-orbit interaction. It is also found that, in general cases, the Pauli, Van Vleck (interband), and Berry curvature susceptibilities are closely related to common magnetization matrix elements, which is in sharp contrast to previous studies. A general form of the off-diagonal magnetic susceptibility is also derived.

  8. Magnetic confinement of repelling Bloch walls

    Science.gov (United States)

    Magyari, E.; Thomas, H.

    1992-01-01

    In a ferromagnet with orthorhombic magneto-crystalline anisotropy, two repelling 180° domain walls (π kinks) can be pushed together to form a 360° domain wall (2π kink) by applying a magnetic field in the easy direction. We show that such a magnetically confined static 360° plane domain wall with Bloch-like structure, connecting two semi-infinite domains with parallel spin orientation, is linearly stable only below a critical strength Bc of the applied field. At B = Bc it becomes unstable with respect to a mode with spin component along the hard direction.

  9. On history and salvation in Emmanuel Levinas and Ernst Bloch

    African Journals Online (AJOL)

    p1243322

    clearly noticeable in what Bloch claims with respect to Goethe. “Goethe … imagined not only the cosmic survival of his essence but precisely also immortality in his work which had become historical and which would remain behind as historical” (PH 1163, italics added). Bloch's texts, however, provides also for the possibility ...

  10. SOME SOLITON PROPERTIES OF COLLIDING VERTICAL BLOCH LINES

    OpenAIRE

    Sukiennicki, A.; Kosiński, R.; Źebrowski, J.

    1988-01-01

    The collisions of two vertical Bloch lines are studied numerically. It is found that soliton like properties of the Bloch lines are obtained for a nonzero damping constant if the power input is large enough to balance the effect of dissipation.

  11. Spin wave vortex from the scattering on Bloch point solitons

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho-Santos, V.L., E-mail: vagson.carvalho@usach.cl [Instituto Federal de Educação, Ciência e Tecnologia Baiano - Campus Senhor do Bonfim, Km 04 Estrada da Igara, 48970-000 Senhor do Bonfim, Bahia (Brazil); Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Elías, R.G., E-mail: gabriel.elias@usach.cl [Departamento de Física, Universidad de Santiago de Chile and CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Nunez, A.S., E-mail: alnunez@dfi.uchile.cl [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Casilla 487-3, Santiago (Chile)

    2015-12-15

    The interaction of a spin wave with a stationary Bloch point is studied. The topological non-trivial structure of the Bloch point manifests in the propagation of spin waves endowing them with a gauge potential that resembles the one associated with the interaction of a magnetic monopole and an electron. By pursuing this analogy, we are led to the conclusion that the scattering of spin waves and Bloch points is accompanied by the creation of a magnon vortex. Interference between such a vortex and a plane wave leads to dislocations in the interference pattern that can be measurable by means of magnon holography.

  12. Engineered surface Bloch waves in graphene-based hyperbolic metamaterials.

    Science.gov (United States)

    Xiang, Yuanjiang; Guo, Jun; Dai, Xiaoyu; Wen, Shuangchun; Tang, Dingyuan

    2014-02-10

    A kind of tunable hyperbolic metamaterial (HMM) based on the graphene-dielectric layered structure at near-infrared frequencies is presented, and the engineered surface Bloch waves between graphene-based HMM and isotropic medium are investigated. Our calculations demonstrate that the frequency and frequency range of surface Bloch waves existence can be tuned by varying the Fermi energy of graphene sheets via electrostatic biasing. Moreover, we show that the frequency range of surface Bloch waves existence can be broadened by decreasing the thickness of the dielectric in the graphene-dielectric layered structure or by increasing the layer number of graphene sheets.

  13. Slow light by Bloch surface wave tunneling.

    Science.gov (United States)

    Koju, Vijay; Robertson, William M

    2014-06-30

    We demonstrate a slow light configuration that makes use of Bloch Surface Waves as an intermediate excitation in a double-prism tunneling configuration. This method is simple compared to the more usual technique for slowing light using the phenomenon of electromagnetically induced transparency in atomic gases or doped ionic crystals operated at temperatures below 4 K. Using a semi-numerical approach, we show that a 1D photonic crystal, a multilayer structure composed of alternating layers of TiO(2) and SiO(2), can be used to slow down light by a factor of up to 400. The results also show that better control of the speed of light can be achieved by changing the number of bilayers and the air-gap thickness appropriately.

  14. Reexamination of Bloch-Messiah reduction

    Science.gov (United States)

    Cariolaro, Gianfranco; Pierobon, Gianfranco

    2016-06-01

    The Bloch-Messiah (BM) reduction allows the decomposition of an arbitrarily complicated Gaussian unitary into a very simple scheme in which linear optical components are separated from nonlinear ones. It is based on the combined application of the eigendecomposition (EID) and singular value decomposition (SVD) of the two matrices associated to the Bogoliubov transformation of the given Gaussian unitary, with the constraint that the unitary matrices appearing in the SVDs must verify a stringent condition, called in the paper "rotation condition". Thus, for a correct evaluation of the BM reduction, one has to choose, among the possible SVD pairs, the pair that meets this condition. The paper develops an approach to this problem, which is based on the introduction of a balancing matrix in the SVDs to fulfill the rotation condition. The theory is illustrated with a few application examples.

  15. Anatomy of the buccopharyngeal cavity of trairão, Hoplias Lacerdae Miranda Ribeiro, 1908 (Characiformes, Erythrinidae

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Reis Raposo Maciel

    2009-09-01

    Full Text Available We studied the buccopharyngeal cavity anatomy of 20 male and female trairão, Hoplias lacerdae (Miranda Ribeiro, 1908 specimens, with 24.41cm average standard-length, fixed in 4% formalin aqueous solution and/or diaphanized and colored with alizarin and alcian blue. The anatomical characteristics of the H. lacerdae buccopharyngeal cavity are: thin lips adherent to the respective maxilla; oral dentition consisting of canine and conical teeth, implanted in the premaxillary, maxillary and dentary arches, and conical teeth in the ectopterygoid and accessory ectopterygoid; smooth tongue, with free apex; dentigerous plates, with conical teeth covering gill arches on the external and internal faces; few gill rakes in gill arch I, with denticles; pharyngeal dental apparatus developed, with conical teeth implanted in the II, III and IV pharyngobranchial and V ceratobranchial cartilage; mucosal layer without significant relief. These characteristics confirm the trairão as being carnivorous in habit, preferentially ictiophagous.

  16. Bio-inspired approach of the fluorescence emission properties in the scarabaeid beetle Hoplia coerulea (Coleoptera): Modeling by transfer-matrix optical simulations

    Science.gov (United States)

    Van Hooijdonk, Eloise; Berthier, Serge; Vigneron, Jean-Pol

    2012-12-01

    Scales of the scarabaeid beetle Hoplia coerulea (Coleoptera) contain fluorescent molecules embedded in a multilayer structure. The consequence of this source confinement is a modification of the fluorescence properties, i.e., an enhancement or inhibition of the emission of certain wavelengths. In this work, we propose a bio-inspired approach to this problem. In other words, we use numerical simulations based on the one-dimensional transfer-matrix formalism to investigate the influence of a Hoplia-like system on emission characteristics and, from the results, we deduce potential technical applications. We reveal that depending on the choice of some parameters (layer thickness, dielectric constant, and position of the emitting source in the structure), it is possible to enhance or inhibit the fluorescence emission for certain wavelengths. This observation could be of great interest to design new optical devices in the field of optoelectronic, solar cells, biosensors, etc.

  17. Orbital Magnetism of Bloch Electrons I. General Formula

    Science.gov (United States)

    Ogata, Masao; Fukuyama, Hidetoshi

    2015-12-01

    We derive an exact formula of orbital susceptibility expressed in terms of Bloch wave functions, starting from the exact one-line formula by Fukuyama in terms of Green's functions. The obtained formula contains four contributions: (1) Landau-Peierls susceptibility, (2) interband contribution, (3) Fermi surface contribution, and (4) contribution from occupied states. Except for the Landau-Peierls susceptibility, the other three contributions involve the crystal-momentum derivatives of Bloch wave functions. Physical meaning of each term is clarified. The present formula is simplified compared with those obtained previously by Hebborn et al. Based on the formula, it is seen first of all that diamagnetism from core electrons and Van Vleck susceptibility are the only contributions in the atomic limit. The band effects are then studied in terms of linear combination of atomic orbital treating overlap integrals between atomic orbitals as a perturbation and the itinerant feature of Bloch electrons in solids are clarified systematically for the first time.

  18. Weighted Composition Operators from Hardy Spaces into Logarithmic Bloch Spaces

    Directory of Open Access Journals (Sweden)

    Flavia Colonna

    2012-01-01

    Full Text Available The logarithmic Bloch space Blog⁡ is the Banach space of analytic functions on the open unit disk 𝔻 whose elements f satisfy the condition ∥f∥=sup⁡z∈𝔻(1-|z|2log⁡  (2/(1-|z|2|f'(z|<∞. In this work we characterize the bounded and the compact weighted composition operators from the Hardy space Hp (with 1≤p≤∞ into the logarithmic Bloch space. We also provide boundedness and compactness criteria for the weighted composition operator mapping Hp into the little logarithmic Bloch space defined as the subspace of Blog⁡ consisting of the functions f such that lim⁡|z|→1(1-|z|2log⁡  (2/(1-|z|2|f'(z|=0.

  19. Skyrmion clusters from Bloch lines in ferromagnetic films

    KAUST Repository

    Garanin, Dmitry A.

    2017-12-29

    Conditions under which various skyrmion objects emerge in experiments on thin magnetic films remain largely unexplained. We investigate numerically centrosymmetric spin lattices in films of finite thickness with ferromagnetic exchange, magnetic anisotropy, and dipole-dipole interaction. Evolution of labyrinth domains into compact topological structures on application of the magnetic field is found to be governed by the configuration of Bloch lines inside domain walls. Depending on the combination of Bloch lines, the magnetic domains evolve into individual skyrmions, biskyrmions, or more complex topological objects. While the geometry of such objects is sensitive to the parameters, their topological charge is uniquely determined by the topological charge of Bloch lines inside the magnetic domain from which the object emerges.

  20. Time resolved optical Bloch oscillations in porous silicon superlattice structures

    Energy Technology Data Exchange (ETDEWEB)

    Ghulinyan, Mher; Gaburro, Zeno; Pavesi, Lorenzo [Department of Physics, University of Trento and INFM, 38050 Povo (Trento) (Italy); Oton, Claudio J. [Department of Physics, University of Trento and INFM, 38050 Povo (Trento) (Italy); Department of Fundamental Physics, University of La Laguna, La Laguna 38204 Tenerife (Spain); Sapienza, Riccardo; Costantino, Paola; Wiersma, Diederik S. [European Laboratory for Nonlinear Spectroscopy and INFM, 50019 Sesto Fiorentino (Florence) (Italy)

    2005-06-01

    We report on the observation of time resolved Bloch oscillations of light waves in optical superlattice structures. The structures are series of coupled microcavities, which are grown in porous silicon with high control of optical parameters. A controlled linear gradient of refractive index along the growth direction was maintained to tilt the photonic band gap of the superlattice. This is in perfect analogy to the tilted electronic miniband structure of a semiconductor in an electric field. In this way an optical Wannier-Stark ladder of equidistant optical modes was formed. Their frequency separation defines the period of the photon Bloch oscillations. The experimental results are in excellent agreement with transfer matrix calculations. The observed phenomenon is the optical counterpart of the well known electronic Bloch oscillations. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Bloch-wave engineering of quantum dot-micropillars for cavity quantum electrodynamics experiments

    DEFF Research Database (Denmark)

    Lermer, Matthias; Gregersen, Niels; Dunzer, Florian

    2012-01-01

    We have employed Bloch-wave engineering to realize submicron diameter ultra-high quality factor GaAs/AlAs micropillars (MPs). The design features a tapered cavity in which the fundamental Bloch mode is subject to an adiabatic transition to match the Bragg mirror Bloch mode. The resulting reduced...

  2. Super Bloch oscillations in the Peyrard–Bishop–Holstein model

    Energy Technology Data Exchange (ETDEWEB)

    Herrero-Gómez, C. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Díaz, E., E-mail: elenadg@fis.ucm.es [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Domínguez-Adame, F. [GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain)

    2012-01-09

    Recently, polarons in the Peyrard–Bishop–Holstein model under DC electric fields were established to perform Bloch oscillations, provided the charge–lattice coupling is not large. In this work, we study this model when the charge is subjected to an applied field with both DC and AC components. Similarly to what happens in the rigid lattice, we find that the carrier undergoes a directed motion or coherent oscillations when the AC field is resonant or detuned with respect to the Bloch frequency, respectively. The electric density current and its Fourier spectrum are also studied to reveal the frequencies involved in the polaron dynamics. -- Highlights: ► We study the Peyrard–Bishop–Holstein model under superimposed DC and AC fields. ► The detuning between the driven and the Bloch frequency sets the polaron dynamics. ► The carrier displays super Bloch oscillations for the non-resonant cases. ► The Morse potential sets the lattice motion which is decoupled of the carrier one. ► The nonlinear coupling leads to a distortion of the wave packet at long times.

  3. Improved Reading Gate For Vertical-Bloch-Line Memory

    Science.gov (United States)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.

    1994-01-01

    Improved design for reading gate of vertical-Bloch-line magnetic-bubble memory increases reliability of discrimination between binary ones and zeros. Magnetic bubbles that signify binary "1" and "0" produced by applying sufficiently large chopping currents to memory stripes. Bubbles then propagated differentially in bubble sorter. Method of discriminating between ones and zeros more reliable.

  4. Bloch-Like Oscillations in Finite Quantum Structures

    DEFF Research Database (Denmark)

    Duggen, Lars; Willatzen, Morten; Lassen, Benny

    ) and derive rather general mathematical relations between quantum systems that allow the existence of Bloch oscillations. References: [1]: G. Corrielli, A. Crespi, G. Della Valle, S. Longhi, and R. Osellame, Nature Communications 4, 1555 (2013) [2]: H. Sanchis-Alepuz, Y. A. Kosevich, and J. Sanchez-Dehesa...

  5. Feeding habits of the catfish Synodontis schall (Bloch & Schneider ...

    African Journals Online (AJOL)

    Synodontis schall (Bloch & Schneider) is an abundant fish in Lake Chamo, but its feeding ecology is not well-known to guide its management. Diet composition and ... Diatoms, zooplankton and insects constituted 89.8% of the volume of food eaten by juveniles, but their importance declined with the size of fish. Importance of ...

  6. Acoustic Bloch Wave Propagation in a Periodic Waveguide

    Science.gov (United States)

    1991-07-24

    matrix (Ramo, Whinnery, and Van Duzer , 1965). Given the amplitudes of the two travelling waves in a single cell, then, we can find the amplitudes of...harmonics (Ramo, Whinnery, and Van Duzer , 1965). ; is interesting to note that because the range of the sum index n in Eq. 2.53 includ negative integers...34backwar. wave structures" (Ramo, Whinnery, and Van Duzer , 1965). 2.4.3 The Convolution Representation The apparent simplicity of the Bloch wave function

  7. On history and salvation in Emmanuel Levinas and Ernst Bloch

    Directory of Open Access Journals (Sweden)

    Salomon J. Terreblanche

    2008-01-01

    Full Text Available This article explores the tension between history and salvation as theme in contemporary social and humanist philosophy. Special reference is made to Emmanuel Levinas’ work in order to delineate the scope of the questions involved, and to critically elucidate the position on history, death and hope in new-Marxist philosopher Ernst Bloch. The article then illuminates Levinas’ phenomenological account of fecundity, parenthood, patience and institutional justice as hopeful moments that are contained in his philosophy on history

  8. Protection of qubit-coherence on a Bloch sphere

    Science.gov (United States)

    Zong, Xiao-Lan; Chu, Wen-Jing; Yang, Ming; Yang, Qing; Cao, Zhuo-Liang

    2017-07-01

    Single qubit pure state is a fundamental resource in quantum information and quantum computation. Therefore, it is of great importance to protect the coherence of single qubits against decoherence. In this letter, we demonstrate that decoherence caused by spontaneous emission can be effectively suppressed by adding a universal static external field. In order to have an intuitive view to the protection effects and its physical mechanisms, we study the coherence evolution of a single qubit on a Bloch sphere. We can clearly see that different external resonant drivings can rotate the Bloch vector around different axes, and the steady-state solution of the master equation (under protection) are visualized on the Bloch sphere. Furthermore, the frequency detuning between the qubit system and the driving is taken into account, and the results show that our protection scheme still works fine in the detuned cases and the smaller the detuning is, the better the protection effect is. In addition, this protocol can protect the coherence of single qubit states with a wide range of driving parameters, and help people to design simple coherence protection schemes for qubit states. The simplicity and the abundance of the current scheme may warrant its experimental realization.

  9. Utopie am Abgrund. Anmerkungen zum Aufstieg Ernst Blochs - Utopia in the abyss. Remarks on the rise of Ernst Bloch

    Directory of Open Access Journals (Sweden)

    Bernhard Streck

    2012-10-01

    Full Text Available The essay wants to deconstruct the genre of utopias so popular in the 20th century political writings. Human history shows manifold respect to stories about non-existent worlds which mix reality and non-reality, but outside the area of Abrahamitic beliefs there was rarely hope for a future. The secular version of such eschatological teachings begins with Karl Marx in the 19th century and culminates in the prophetic as well as revolutionary writings of Ernst Bloch around the terrible wars of the 20th century. This philosopher succeeded in both parts of post-war Germany and is still venerated inside and outside the academias. Compared with the so-called dystopias of Max Weber, Aldous Huxley or George Orwell the political visions of Bloch lack any sense of reality and seem to be quite useless to the understanding of present tendencies in world politics.

  10. Properties of Floquet-Bloch space harmonics in 1D periodic magneto-dielectric structures

    DEFF Research Database (Denmark)

    Breinbjerg, O.

    2012-01-01

    Recent years have witnessed a significant research interest in Floquet-Bloch analysis for determining the homogenized permittivity and permeability of metamaterials consisting of periodic structures. This work investigates fundamental properties of the Floquet-Bloch space harmonics in a 1......-dimensional magneto-dielectric lossless structure supporting a transverse-electric-magnetic Floquet-Bloch wave; in particular, the space harmonic permittivity and permeability, as well as the space harmonic Poynting vector....

  11. Operational matrix approach for approximate solution of fractional model of Bloch equation

    Directory of Open Access Journals (Sweden)

    Harendra Singh

    2017-04-01

    Full Text Available In present paper operational matrix of integration for Laguerre polynomial is used to solve fractional model of Bloch equation in nuclear magnetic resonance (NMR. The operational matrix converts the Bloch equation in a system of linear algebraic equations. Solving system we obtain the approximate solutions for fractional Bloch equation. Results are compared with existing methods and exact solution. Graphs are plotted for different fractional values of time derivatives.

  12. Bipolaron assisted Bloch-like oscillations in organic lattices

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Luiz Antonio, E-mail: ribeirojr@unb.br [International Center for Condensed Matter Physics, University of Brasília, P.O. Box 04531, 70.919-970, Brasília, DF (Brazil); University of Brasília, UnB Faculty of Planaltina, 73.345-010, Planaltina, DF (Brazil); Ferreira da Cunha, Wiliam; Magela e Silva, Geraldo [Institute of Physics, University of Brasília, 70.919-970, Brasília (Brazil)

    2017-06-15

    The transport of a dissociated bipolaron in organic one-dimensional lattices is theoretically investigated in the scope of a tight-binding model that includes electron-lattice interactions and an external electric field. Remarkably, the results point to a physical picture in which the dissociated bipolaron propagates as a combined state of two free-like electrons that coherently perform spatial Bloch oscillations (BO) above a critical field strength. It was also obtained that the BO's trajectory presents a net forward motion in the direction of the applied electric field. The impact of dynamical disorder in the formation of electronic BOs is determined.

  13. Traffic restrictions on Routes Bloch, Maxwell and Bohr

    CERN Multimedia

    TS Department

    2008-01-01

    Excavation and pipework is being carried out in the framework of the transfer of the waste water treatment plant for the effluents from the surface treatment workshops from Building 254 to Building 676, currently under construction. This work may encroach onto Routes Bloch, Maxwell and Bohr and disrupt the flow of traffic. Users are requested to comply with the road signs that will be erected. The work is expected to last until the beginning of December 2008. Thank you for your understanding. TS/CE and TS/FM Groups Tel.7 4188 or 16 4314

  14. Lie-Poisson bifurcations for the Maxwell-Bloch equations

    Energy Technology Data Exchange (ETDEWEB)

    David, D.

    1990-01-01

    We present a study of the set of Maxwell-Bloch equations on R{sup 3} from the point of view of Hamiltonian dynamics. These equations are shown to be bi-Hamiltonian, on the one hand, and to possess several inequivalent Lie-Poisson structures, on the other hand, parametrized by the group SL(2,R). Each structure is characterized by a particular distinguished function. The level sets of this function provide two-dimensional surfaces onto which the motion takes various symplectic forms. 4 refs.

  15. Bloch electrons in 2D periodic electric and magnetic fields; Bloch-Elektronen in 2D periodischen elektrischen und magnetischen Feldern

    Energy Technology Data Exchange (ETDEWEB)

    Naundorf, B.

    2001-06-01

    The following topics were dealt with: electrons in periodic potentials, Bloch states, Landau states, wave packets, Harper equation, uncoupled Landau band states, matrix elements and matrix equations, periodic electric and magnetic fields (WL)

  16. Bloch-Redfield equations for modeling light-harvesting complexes.

    Science.gov (United States)

    Jeske, Jan; Ing, David J; Plenio, Martin B; Huelga, Susana F; Cole, Jared H

    2015-02-14

    We challenge the misconception that Bloch-Redfield equations are a less powerful tool than phenomenological Lindblad equations for modeling exciton transport in photosynthetic complexes. This view predominantly originates from an indiscriminate use of the secular approximation. We provide a detailed description of how to model both coherent oscillations and several types of noise, giving explicit examples. All issues with non-positivity are overcome by a consistent straightforward physical noise model. Herein also lies the strength of the Bloch-Redfield approach because it facilitates the analysis of noise-effects by linking them back to physical parameters of the noise environment. This includes temporal and spatial correlations and the strength and type of interaction between the noise and the system of interest. Finally, we analyze a prototypical dimer system as well as a 7-site Fenna-Matthews-Olson complex in regards to spatial correlation length of the noise, noise strength, temperature, and their connection to the transfer time and transfer probability.

  17. Bloch-Zener oscillations in a tunable optical honeycomb lattice

    Energy Technology Data Exchange (ETDEWEB)

    Uehlinger, Thomas; Greif, Daniel; Jotzu, Gregor; Esslinger, Tilman [Institute for Quantum Electronics, ETH Zurich, 8093 Zurich (Switzerland); Tarruell, Leticia [Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland and LP2N, Universite Bordeaux 1, IOGS, CNRS, 351 cours de la Liberation, 33405 Talence (France)

    2013-12-04

    Ultracold gases in optical lattices have proved to be a flexible tool to simulate many different phenomena of solid state physics [1, 2]. Recently, optical lattices with complex geometries have been realized [3, 4, 5, 6, 7], paving the way to simulating more realistic systems. The honeycomb structure has recently become accessible in an optical lattice composed of mutually perpendicular laser beams. This lattice structure exhibits topological features in its band structure – the Dirac points. At these points, two energy bands intersect linearly and the particles behave as relativistic Dirac fermions. In optical lattices, Bloch oscillations [8] resolved both in time and in quasi-momentum space can be directly observed. We make use of such Bloch-Zener oscillations to probe the vanishing energy gap at the Dirac points as well as their position in the band structure. In small band gap regions, we observe Landau-Zener tunneling [7, 9] to the second band and the regions of maximum transfer can be identified with the position of the Dirac points.

  18. Leaky Bloch-like surface waves in the radiation-continuum for sensitivity enhanced biosensors via azimuthal interrogation.

    Science.gov (United States)

    Koju, Vijay; Robertson, William M

    2017-06-12

    Dielectric multilayer structures with a grating profile on the top-most layer adds an additional degree of freedom to the phase matching conditions for Bloch surface wave excitation. The conditions for Bloch surface wave coupling can be achieved by rotating both polar and azimuthal angles. The generation of Bloch surface waves as a function of azimuthal angle has similar characteristics to conventional grating coupled Bloch surface waves. However, azimuthally generated Bloch surface waves have enhanced angular sensitivity compared to conventional polar angle coupled modes, which makes them appropriate for detecting tiny variations in surface refractive index due to the addition of nano-particles such as protein molecules.

  19. From Bloch to random lasing in ZnO self-assembled nanostructures

    DEFF Research Database (Denmark)

    Garcia-Fernandez, Pedro David; Cefe, López

    2013-01-01

    In this paper, we present measurements on UV lasing in ZnO ordered and disordered nanostructures. Bloch lasing is achieved in the ordered structures by exploiting very low group-velocity Bloch modes in ZnO photonic crystals. In the second case, random lasing is observed in ZnO photonic glasses. We...... study the lasing threshold in both cases and its dependence on the structural parameters. Finally, we present the transition from Bloch to random lasing by deliberately doping a ZnO inverse photonic crystal with a controlled amount of lattice vacancies effectively converting it into a translationally...

  20. The Optical Bloch oscillation in chirped one-dimensional superconducting photonic crystal

    Science.gov (United States)

    Zhang, Zhengren; Long, Yang; Zhang, Liwei; Yin, Pengfei; Xue, Chunhua

    2017-09-01

    We exploit theoretically the propagation properties of electromagnetic waves in nanoscale one-dimensional superconducting photonic crystal. The Wannier Stark ladders can be formed in the photonic crystal by varying the thickness of the dielectric layers linearly across the structure. The dynamics behavior of a Gaussian pulse transmitting through the structure is simulated theoretically. We find that photons undergo Bloch oscillations inside tilted photonic bands and the Bloch oscillations are sensitive to the change of temperature in the range of 3-8 K. It is demonstrated that our structure is possible to realize tunable optical Bloch oscillations by controlling the temperature of superconducting material.

  1. Bloch-Messiah reduction of Gaussian unitaries by Takagi factorization

    Science.gov (United States)

    Cariolaro, Gianfranco; Pierobon, Gianfranco

    2016-12-01

    The Bloch-Messiah (BM) reduction allows the decomposition of an arbitrarily complicated Gaussian unitary into a very simple scheme in which linear optical components are separated from nonlinear ones. The nonlinear part is due to the squeezing possibly present in the Gaussian unitary. The reduction is usually obtained by exploiting the singular value decomposition (SVD) of the matrices appearing in the Bogoliubov transformation of the given Gaussian unitary. This paper discusses a different approach, where the BM reduction is obtained in a straightforward way. It is based on the Takagi factorization of the (complex and symmetric) squeeze matrix and has the advantage of avoiding several matrix operations of the previous approach (polar decomposition, eigendecomposition, SVD, and Takagi factorization). The theory is illustrated with an application example in which the previous and present approaches are compared.

  2. DAGON: a 3D Maxwell-Bloch code

    Science.gov (United States)

    Oliva, Eduardo; Cotelo, Manuel; Escudero, Juan Carlos; González-Fernández, Agustín.; Sanchís, Alberto; Vera, Javier; Vicéns, Sergio; Velarde, Pedro

    2017-05-01

    The amplification of UV radiation and high order harmonics (HOH) in plasmas is a subject of raising interest due to its different potential applications in several fields like environment and security (detection at distance), biology, materials science and industry (3D imaging) and atomic and plasma physics (pump-probe experiments). In order to develop these sources, it is necessary to properly understand the amplification process. Being the plasma an inhomogeneous medium which changes with time, it is desirable to have a full time-dependent 3D description of the interaction of UV and XUV radiation with plasmas. For these reasons, at the Instituto de Fusíon Nuclear we have developed DAGON, a 3D Maxwell-Bloch code capable of studying the full spationtemporal structure of the amplification process abovementioned.

  3. Kalb-Ramond field localization on the Bloch brane

    Science.gov (United States)

    Cruz, W. T.; Maluf, R. V.; Almeida, C. A. S.

    2013-08-01

    This work deals with new results on the Kalb-Ramond (KR) field localization in brane-world models. We consider a five-dimensional warped spacetime with an embedded 4D thick brane which is generated by two real scalar fields coupled with gravity (the so called Bloch brane). We find a KR field zero mode localized with the inclusion of the dilaton coupling. Analyzing the massive spectrum, we detected a series of resonant modes that arise from the solutions of the Schrödinger-like equation for KR field. The effects of the brane thickness and of the dilaton coupling over the resonance structures are determined. Such analysis is extended to the resonance lifetimes of the massive modes, allowing a better understanding on the localization mechanism of the model.

  4. Entanglement and the three-dimensionality of the Bloch ball

    Energy Technology Data Exchange (ETDEWEB)

    Masanes, Ll., E-mail: ll.masanes@gmail.com [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Müller, M. P. [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, D-69120 Heidelberg (Germany); Pérez-García, D. [Departamento de Analisis Matematico and IMI, Universidad Complutense de Madrid, 28040 Madrid (Spain); Augusiak, R. [ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels, Barcelona (Spain)

    2014-12-15

    We consider a very natural generalization of quantum theory by letting the dimension of the Bloch ball be not necessarily three. We analyze bipartite state spaces where each of the components has a d-dimensional Euclidean ball as state space. In addition to this, we impose two very natural assumptions: the continuity and reversibility of dynamics and the possibility of characterizing bipartite states by local measurements. We classify all these bipartite state spaces and prove that, except for the quantum two-qubit state space, none of them contains entangled states. Equivalently, in any of these non-quantum theories, interacting dynamics is impossible. This result reveals that “existence of entanglement” is the requirement with minimal logical content which singles out quantum theory from our family of theories.

  5. Bloch-surface-waves based photonic devices studied by leakage radiation microscopy

    Science.gov (United States)

    Gulkin, D. N.; Abrashitova, K. A.; Safronov, K. R.; Kokareva, N. G.; Antropov, I. M.; Bessonov, V. O.; Fedyanin, A. A.

    2017-09-01

    The Bloch-surface-wave photonic devices were for the first time manufactured by the two-photon polymerization lithography. Bloch-surface-wave modes excitation and propagation were visualized by the leakage radiation microscopy. The mode structure of the guided light was characterized by the back-focal-plane imaging. It was demonstrated that the photonic devices are able to guide light in multimode regime.

  6. Bloch wave deafness and modal conversion at a phononic crystal boundary

    OpenAIRE

    Vincent Laude; Rayisa P. Moiseyenko; Sarah Benchabane; Nico F. Declercq

    2011-01-01

    International audience; We investigate modal conversion at the boundary between a homogeneous incident medium and a phononic crystal, with consideration of the impact of symmetry on the excitation of Bloch waves. We give a quantitative criterion for the appearance of deaf Bloch waves, which are antisymmetric with respect to a symmetry axis of the phononic crystal, in the frame of generalized Fresnel formulas for reflection and transmission at the phononic crystal boundary. This criterion is u...

  7. Philippe Bloch: Reducing distance between experiments and CERN

    CERN Multimedia

    2009-01-01

    With its unique combination of several hundred staff members and thousands of users from around the world sharing offices and physics data and profiting from mutually beneficial exchanges of know-how and expertise, the PH Department is a good example of a successful worldwide collaboration, set up as it was to construct and run the Laboratory’s physics experiments. The PH Depart-ment has always played host to thousands of users that contribute to CERN experiments and work on them, and whose numbers are set to grow in the years to come. With his long-standing experience as a user and then as the head of the CERN group within the CMS collaboration, Philippe Bloch, the new PH Department Head, is in favour of closer links between the Department and the experiments. "I think that the PH management should have a direct link to the experiments, and to do so we are holding regular management team meetings comprising members of the Department’s management and the e...

  8. Haematological studies of climbing perch (Anabas testudineus Bloch

    Directory of Open Access Journals (Sweden)

    Sukasem, N.

    2005-02-01

    Full Text Available Some blood parameters of the climbing perch (Anabas testudineus Bloch i.e. red (RBC and white (WBC blood cell count, percent haematocrit (HTC, hemoglobin, plasma protein as well as hepatosomatic index (HSI were studied. There were no statistically significant difference (p>0.05 in average body weight and length of fish from the earthen pond and net cage culture, which were 16.85±1.46 g and 16.24±2.42 g, respectively, for the weight and 10.02±0.25 and 9.74±0.37 cm, respectively, for the length. Haematologicalstudies revealed that RBC, WBC including percent HTC levels of the fish from earthen pond and net cage were not significantly different (> 0.05. Whereas hemoglobin and serum protein concentration of the fish sampling from net cage were higher than those sampled from the earthen pond (p<0.05, with value of 12.21± 0.91 g/dl and 11.12±0.85 g/dl for hemoglobin and 4.61±0.50 mg/dl and 3.87±0.62 mg/dl for serum protein, respectively. HSI of the fish cultured in the earthen pond was significantly (p<0.05 higher than that of fish reared in net cage, with value of 1.93±0.12% and 1.66±0.12%, respectively.

  9. Development of Formaldehyde Biosensor for Determination of Formalin in Fish Samples; Malabar Red Snapper (Lutjanus malabaricus and Longtail Tuna (Thunnus tonggol

    Directory of Open Access Journals (Sweden)

    Bohari Noor Aini

    2016-06-01

    Full Text Available Electrochemical biosensors are widely recognized in biosensing devices due to the fact that gives a direct, reliable, and reproducible measurement within a short period. During bio-interaction process and the generation of electrons, it produces electrochemical signals which can be measured using an electrochemical detector. A formaldehyde biosensor was successfully developed by depositing an ionic liquid (IL (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][Otf], gold nanoparticles (AuNPs, and chitosan (CHIT, onto a glassy carbon electrode (GCE. The developed formaldehyde biosensor was analyzed for sensitivity, reproducibility, storage stability, and detection limits. Methylene blue was used as a redox indicator for increasing the electron transfer in the electrochemical cell. The developed biosensor measured the NADH electron from the NAD+ reduction at a potential of 0.4 V. Under optimal conditions, the differential pulse voltammetry (DPV method detected a wider linear range of formaldehyde concentrations from 0.01 to 10 ppm within 5 s, with a detection limit of 0.1 ppm. The proposed method was successfully detected with the presence of formalin in fish samples, Lutjanus malabaricus and Thunnus Tonggol. The proposed method is a simple, rapid, and highly accurate, compared to the existing technique.

  10. Experimental and theoretical demonstration of acoustic Bloch oscillations in porous silicon structures

    Energy Technology Data Exchange (ETDEWEB)

    Lazcano, Z.; Arriaga, J., E-mail: arriaga@ifuap.buap.mx [Instituto de Física, Benemérita Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110-A, Ciudad Universitaria, 72570 Puebla (Mexico); Aliev, G. N. [Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2014-04-21

    We report the theoretical calculations and the experimental demonstration of acoustic Bloch oscillations and Wannier-Stark ladders in linear tilted multilayer structures based on porous silicon. The considered structures consist of layers with constant porosity alternated by layers with a linear gradient in the parameter η=1/v{sub L}{sup 2} along the growth direction in order to tilt the acoustic band gap. The purpose of this gradient is to mimic the tilted electronic miniband structure of a superlattice semiconductor under an external electric field. In this way, acoustic Wannier-Stark ladders of equidistant modes are formed and they were experimentally confirmed in the transmission spectrum around 1.2 GHz. Their frequency separation defines the period of the acoustic Bloch oscillations. We fabricated three different structures with the same thicknesses but different values in the η parameter to observe the effect on the period of the Bloch oscillations. We measured the acoustic transmission spectra in the frequency domain, and by using the Fourier transform, we obtained the transmission in the time domain. The transmission spectra of the fabricated samples show acoustic Bloch oscillations with periods of 27, 24, and 19 ns. The experimental results are in good agreement with the transfer matrix calculations. The observed phenomenon is the acoustic counterpart of the well known electronic Bloch oscillations.

  11. Integral type operators from normal weighted Bloch spaces to QT,S spaces

    Directory of Open Access Journals (Sweden)

    Yongyi GU

    2016-08-01

    Full Text Available Operator theory is an important research content of the analytic function space theory. The discussion of simultaneous operator and function space is an effective way to study operator and function space. Assuming that  is an analytic self map on the unit disk Δ, and the normal weighted bloch space μ-B is a Banach space on the unit disk Δ, defining a composition operator C∶C(f=f on μ-B for all f∈μ-B, integral type operator JhC and CJh are generalized by integral operator and composition operator. The boundeness and compactness of the integral type operator JhC acting from normal weighted Bloch spaces to QT,S spaces are discussed, as well as the boundeness of the integral type operators CJh acting from normal weighted Bloch spaces to QT,S spaces. The related sufficient and necessary conditions are given.

  12. Bloch wave deafness and modal conversion at a phononic crystal boundary

    Directory of Open Access Journals (Sweden)

    Vincent Laude

    2011-12-01

    Full Text Available We investigate modal conversion at the boundary between a homogeneous incident medium and a phononic crystal, with consideration of the impact of symmetry on the excitation of Bloch waves. We give a quantitative criterion for the appearance of deaf Bloch waves, which are antisymmetric with respect to a symmetry axis of the phononic crystal, in the frame of generalized Fresnel formulas for reflection and transmission at the phononic crystal boundary. This criterion is used to index Bloch waves in the complex band structure of the phononic crystal, for directions of incidence along a symmetry axis. We argue that within deaf frequency ranges transmission is multi-exponential, as it is within frequency band gaps.

  13. Observation of Bloch oscillations in complex PT-symmetric photonic lattices

    CERN Document Server

    Wimmer, Martin; Christodoulides, Demetrios; Peschel, Ulf

    2016-01-01

    Light propagation in periodic environments is often associated with a number of interesting and potentially useful processes. If a crystalline optical potential is also linearly ramped, light can undergo periodic Bloch oscillations, a direct outcome of localized Wannier-Stark states and their equidistant eigenvalue spectrum. Even though these effects have been extensively explored in conservative settings, this is by no means the case in non-Hermitian photonic lattices encompassing both amplification and attenuation. Quite recently, Bloch oscillations have been predicted in parity-time-symmetric structures involving gain and loss in a balanced fashion. While in a complex bulk medium, one intuitively expects that light will typically follow the path of highest amplification, in a periodic system this behavior can be substantially altered by the underlying band structure. Here, we report the first experimental observation of Bloch oscillations in parity-time-symmetric mesh lattices. We show that these revivals ...

  14. Shapes displayed with durations in the microsecond range do not obey Bloch's law of temporal summation.

    Science.gov (United States)

    Greene, Ernest; Ogden, R Todd

    2013-01-01

    Shape patterns were displayed with simultaneous brief flashes from a light-emitting diode array. Flash durations in the microsecond range and luminous intensities were adjusted to vary the degree of successful shape recognition. Four experiments were conducted to test whether Bloch's law would apply in this task. Bloch's law holds that for very brief flashes the perceptual threshold is determined by the total number of photons being delivered, i.e., there is reciprocity of intensity and duration. The present results did not find that effectiveness of flashes was based on the total quantity of photons, as predicted by Bloch's law. Additionally, the evidence points to a visual mechanism that has ultra-high temporal precision that either registers the rate of photon flux or the duration of flashes.

  15. Shapes Displayed with Durations in the Microsecond Range Do Not Obey Bloch's Law of Temporal Summation

    Directory of Open Access Journals (Sweden)

    Ernest Greene

    2013-09-01

    Full Text Available Shape patterns were displayed with simultaneous brief flashes from a light-emitting diode array. Flash durations in the microsecond range and luminous intensities were adjusted to vary the degree of successful shape recognition. Four experiments were conducted to test whether Bloch's law would apply in this task. Bloch's law holds that for very brief flashes the perceptual threshold is determined by the total number of photons being delivered, i.e., there is reciprocity of intensity and duration. The present results did not find that effectiveness of flashes was based on the total quantity of photons, as predicted by Bloch's law. Additionally, the evidence points to a visual mechanism that has ultra-high temporal precision that either registers the rate of photon flux or the duration of flashes.

  16. Photonic Bloch-dipole-Zener Oscillations in Binary Parabolic Optical Waveguide Arrays

    CERN Document Server

    Zheng, Ming Jie; Yu, Kin Wah

    2011-01-01

    We have studied the propagation and Zener tunneling of light in the binary parabolic optical waveguide array (BPOWA), which consists of two evanescently coupled dissimilar optical waveguides. Due to Bragg reflections, BPOWA attains two minibands separated by a minigap at the zone boundary. Various coherent superpositions of optical oscillations and Zener tunneling occur for different parameters on the phase diagram. In particular, Bloch-Zener oscillation and a different type of Bloch-dipole-Zener oscillation are obtained by the field-evolution analysis. The results may have potential applications in optical splitting and waveguiding devices and shed light on the coherent phenomena in optical lattices.

  17. Bloch-wave engineered submicron-diameter quantum-dot micropillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Reitzenstein, Stephan

    2013-01-01

    The semiconductor micropillar is attractive for cavity QED experiments. For strong coupling, the figure of merit is proportional to Q/√V, and a design combining a high Q and a low mode volume V is thus desired. However, for the standard submicron diameter design, poor mode matching between the ca...... the cavity and the DBR Bloch mode limits the Q. We present a novel adiabatic design where Bloch-wave engineering is employed to improve the mode matching, allowing the demonstration of a record-high vacuum Rabi splitting of 85 μeV and a Q of 13600 for a 850 nm diameter micropillar....

  18. Generalized Floquet theory: application to dynamical systems with memory and Bloch's theorem for nonlocal potentials.

    Science.gov (United States)

    Traversa, Fabio L; Di Ventra, Massimiliano; Bonani, Fabrizio

    2013-04-26

    Floquet theory is a powerful tool in the analysis of many physical phenomena, and extended to spatial coordinates provides the basis for Bloch's theorem. However, in its original formulation it is limited to linear systems with periodic coefficients. Here, we extend the theory by proving a theorem for the general class of systems including linear operators commuting with the period-shift operator. The present theorem greatly expands the range of applicability of Floquet theory to a multitude of phenomena that were previously inaccessible with this type of analysis, such as dynamical systems with memory. As an important extension, we also prove Bloch's theorem for nonlocal potentials.

  19. Spin-dependent semiconductor Bloch equations: Microscopic theory of Bir-Aronov-Pikus spin relaxation

    Science.gov (United States)

    Lechner, C.; Rössler, U.

    2005-10-01

    Semiconductor Bloch equations, in their extension including the spin degree of freedom of the carriers, are capable to describe spin dynamics on a microscopic level. In the presence of free holes, electron spins can flip simultaneously with hole spins due to electron-hole exchange interaction. This mechanism named after Bir, Aronov, and Pikus is described here by using the extended semiconductor Bloch equations [Phys. Status Solidi B 234, 385 (2002)] and considering carrier-carrier interaction beyond the Hartree-Fock truncation. As a result we derive microscopic expressions for spin-relaxation and spin-dephasing rates.

  20. Metazoários parasitos de seis espécies de peixes do Reservatório de Lajes, Estado do Rio de Janeiro, Brasil Metazoan parasites of six fishes species from Lajes Reservoir in the State of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Aline R. Paraguassú

    2007-09-01

    Full Text Available Entre abril de 2002 e julho de 2003, foram necropsiados 231 espécimes de peixes: 39 Astyanax bimaculatus (Linnaeus, 1758, 79 A. fasciatus (Cuvier, 1819, 23 Hypostomus affinis (Steindachner, 1877, 26 Hoplias malabaricus (Bloch, 1794, 30 Loricariichthys castaneus (Castelnau, 1855 e 34 Trachelyopterus striatulus (Steindachner, 1876 provenientes do Reservatório de Lajes (22º42' - 22º50'S, 43º53' 44º05'O, Estado do Rio de Janeiro, Brasil, para estudo das suas comunidades parasitárias. A maioria dos espécimes de H. affinis (95,6% e H. malabaricus (84,6% estavam parasitados por pelo menos uma espécie de metazoário. Em A. bimaculatus, A. fasciatus, L. castaneus e T. striatulus 41%, 39,2%, 56,7% e 14,7% dos espécimes estavam parasitados, respectivamente. Foram coletadas oito diferentes espécies de metazoários parasitos: 2 em A. bimaculatus, 3 em A. fasciatus, 3 em H. affinis, 4 em H. malabaricus, 4 em L. castaneus e 1 em T. striatulus. As comunidades de metazoários parasitos das seis espécies de peixes estudadas apresentaram típico padrão de distribuição agregada. Foram observados dois casos de correlação negativa entre a abundância e a prevalência parasitárias e o comprimento total dos hospedeiros. A comunidade parasitária de L. castaneus apresentou os maiores valores de intensidade média, índice de dispersão e diversidade. As comunidades parasitárias dos peixes estudados apresentaram escassez de correlação entre a abundância, riqueza parasitária e diversidade com o comprimento total dos hospedeiros. Os baixos valores de riqueza e diversidade das comuni-dades parasitárias podem ser atribuídos as características oligotróficas do Reservatório de Lajes.From April 2002 to July 2003, 231 freshwater fishes from Lajes Reservoir in the State of Rio de Janeiro, Brazil (22º42' - 22º50'S, 43º53' - 44º05'W were necropsied to study their community metazoan parasites: 39 Astyanax bimaculatus (Linnaeus, 1758, 79 A. fasciatus

  1. Computational Modeling of Bloch Surface Waves in One-Dimensional Periodic and Aperiodic Multilayer Structures

    Science.gov (United States)

    Koju, Vijay

    Photonic crystals and their use in exciting Bloch surface waves have received immense attention over the past few decades. This interest is mainly due to their applications in bio-sensing, wave-guiding, and other optical phenomena such as surface field enhanced Raman spectroscopy. Improvement in numerical modeling techniques, state of the art computing resources, and advances in fabrication techniques have also assisted in growing interest in this field. The ability to model photonic crystals computationally has benefited both the theoretical as well as experimental communities. It helps the theoretical physicists in solving complex problems which cannot be solved analytically and helps to acquire useful insights that cannot be obtained otherwise. Experimentalists, on the other hand, can test different variants of their devices by changing device parameters to optimize performance before fabrication. In this dissertation, we develop two commonly used numerical techniques, namely transfer matrix method, and rigorous coupled wave analysis, in C++ and MATLAB, and use two additional software packages, one open-source and another commercial, to model one-dimensional photonic crystals. Different variants of one-dimensional multilayered structures such as perfectly periodic dielectric multilayers, quasicrystals, aperiodic multilayer are modeled, along with one-dimensional photonic crystals with gratings on the top layer. Applications of Bloch surface waves, along with new and novel aperiodic dielectric multilayer structures that support Bloch surface waves are explored in this dissertation. We demonstrate a slow light configuration that makes use of Bloch Surface Waves as an intermediate excitation in a double-prism tunneling configuration. This method is simple compared to the more usual techniques for slowing light using the phenomenon of electromagnetically induced transparency in atomic gases or doped ionic crystals operated at temperatures below 4K. Using a semi

  2. Characterization of Modified Look Locker (MOLLI) using Bloch Simulations and Corroboration with Scan Measurements

    NARCIS (Netherlands)

    Gai, N.D.; Stehning, C.; Nacif, M.; Bluemke, D.

    2012-01-01

    This manuscript shows that Bloch simulations provide a convenient way for predicting response of a modified Look Locker (MOLLI) T1 mapping sequence to various parameters that affect T1 accuracy of the technique. In particular, the effect of T2 on accuracy is shown. Phantom- and first in vivo

  3. The Contributions of Felix Bloch and W. V. Houston to the Electron Theory of Metals

    Science.gov (United States)

    Rorschach, H. E., Jr.

    1970-01-01

    Discusses the contributions of Bloch and Houston to the electron theory of metals. Contains (1) a biographical note on W. V. Houston, (2) a review of the development of the electron theory of metals, and (3) a discussion of gravitationally induced electric fields. Bibliography. (LC)

  4. Bloch oscillations and accelerated Bose–Einstein condensates in an optical lattice

    Energy Technology Data Exchange (ETDEWEB)

    Sacchetti, Andrea, E-mail: andrea.sacchetti@unimore.it

    2017-01-30

    Highlights: • Discrete nonlinear Schrödinger model for accelerated BECs in optical lattices. • Numerical computation of wavefunction BECs dynamics. • Correlation between nonlinearity and the oscillating period of the BEC's center of mass. • Discussion of the validity of the Bloch Theorem for accelerated BECs in an optical lattice. - Abstract: We discuss the method for the measurement of the gravity acceleration g by means of Bloch oscillations of an accelerated BEC in an optical lattice. This method has a theoretical critical point due to the fact that the period of the Bloch oscillations depends, in principle, on the initial shape of the BEC wavepacket. Here, by making use of the nearest-neighbor model for the numerical analysis of the BEC wavefunction, we show that in real experiments the period of the Bloch oscillations does not really depend on the shape of the initial wavepacket and that the relative uncertainty, due to the fact that the initial shape of the wavepacket may be asymmetrical, is smaller than the one due to experimental errors. Furthermore, we also show that the relation between the oscillation period and the scattering length of the BEC's atoms is linear; this fact suggests us a new experimental procedure for the measurement of the scattering length of atoms.

  5. Don Bloch's vision for Collaborative Family Health Care: Progress and next steps.

    Science.gov (United States)

    Peek, C J

    2015-06-01

    Don Bloch is the central figure in the origin story for the field of collaborative family health care; the journal Families, Systems, & Health; and for the Collaborative Family Healthcare Association (CFHA). He exerted extraordinary intellectual and practical leadership for all 3. He convened a national working session in 1994 that took stock of the field and set out next steps, one of which was to create the interprofessional organization dedicated to collaborative family health care that is now CFHA. As part of honoring Don Bloch's contributions to the field and this journal, this article sets out tenets of his original vision and traces next steps toward this vision generated by national groups between 1994 and 2014, showing what is the same or different over these 20 years, and especially what this means for the field going forward. Precepts of Don Bloch's original vision are drawn from his writings, including the briefing papers he prepared for the national Wingspread group convened in 1994, which also set out next steps for the field. These steps are then compared with next developmental steps for the field generated by CFHA conference attendees in 2004 and again in 2014, after reviewing the history of the organization and the field. Much of Don Bloch's vision has remained relevant to health care transformation, with a number of areas showing significant accomplishment and acceptance, whereas others remain aspirational, and a few others arguably being more difficult to achieve now than when Don articulated them. (c) 2015 APA, all rights reserved).

  6. Proof of the extended Bloch-Messiah theorem in the thermal Hartree-Fock-Bogoliubov theory

    Science.gov (United States)

    Tanabe, K.; Sugawara-Tanabe, K.

    1990-09-01

    It is shown that an application of the thermo field dynamics (TFD) to the thermal Hartree-Fock-Bogoliubov (THFB) theory leads to the extended form of the Bloch-Messiah theorem for the finite temperature formalism. The generalized density matrix defined on the enlarged operator space including tilded into account the thermal fluctuation of fermion number for the system under consideration.

  7. Electronic energy band parameters of CsCl evaluated on core Bloch states and plane waves

    Energy Technology Data Exchange (ETDEWEB)

    Syrotyuk, S.V. [Semiconductor Electronics Department, National University ' Lviv Polytechnic' , S. Bandera str. 12, Lviv 79013 (Ukraine); Chornodolskyy, Ya.M. [Physics Department, Ivan Franko National University of Lviv, Kyryla i Mefodiya str. 8, Lviv 79005 (Ukraine)], E-mail: chornodolsky@ukr.net; Stryganyuk, G.B. [HASYLAB at DESY, Notkestr. 85, Hamburg 22607 (Germany); Voloshinovskii, A.S. [Physics Department, Ivan Franko National University of Lviv, Kyryla i Mefodiya str. 8, Lviv 79005 (Ukraine); Rodnyi, P.A. [St. Petersburg State Polytechnical University, Polytekhnicheskaya 29, St. Petersburg 195251 (Russian Federation)

    2007-04-15

    Electronic energy bands of CsCl crystal have been calculated within the mixed basis approach with using the core Bloch states and plane waves. The calculated energy parameters of the crystal are in the satisfactory agreement with the experimental data obtained from the analysis of the core-valence luminescence spectra. The obtained results form a base for calculation of CVL spectra parameters.

  8. Beam splitter and combiner based on Bloch oscillations in spatially modulated waveguide arrays

    CERN Document Server

    Zhang, Yiqi; Zhong, Weiping; Wen, Feng; Guo, Yang; Guo, Yao; Lu, Keqing; Zhang, Yanpeng

    2014-01-01

    We numerically investigate the light beam propagation in periodic waveguide arrays which are elaborately modulated with certain structures. We find that the light beam may split, coalesce, deflect, and be localized during propagation in these spatially modulated waveguide arrays. All the phenomena originate from Bloch oscillations, and supply possible method for fabricating on-chip beam splitters and beam combiners.

  9. Populating the Large-Wavevector Realm: Bloch Volume Plasmon Polaritons in Hyperbolic and Extremely Anisotropic Metamaterials

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Babicheva, Viktoriia; Orlov, A. A.

    2014-01-01

    Optics of hyperbolic metamaterials is revisited in terms of large-wavevector waves, evanescent in isotropic media but propagating in presence of extreme anisotropy. Identifying the physical nature of these waves as Bloch volume plasmon polaritons, we derive their existence conditions and outline...

  10. Comprehensive solutions to the Bloch equations and dynamical models for open two-level systems

    Science.gov (United States)

    Skinner, Thomas E.

    2018-01-01

    The Bloch equation and its variants constitute the fundamental dynamical model for arbitrary two-level systems. Many important processes, including those in more complicated systems, can be modeled and understood through the two-level approximation. It is therefore of widespread relevance, especially as it relates to understanding dissipative processes in current cutting-edge applications of quantum mechanics. Although the Bloch equation has been the subject of considerable analysis in the 70 years since its inception, there is still, perhaps surprisingly, significant work that can be done. This paper extends the scope of previous analyses. It provides a framework for more fully understanding the dynamics of dissipative two-level systems. A solution is derived that is compact, tractable, and completely general, in contrast to previous results. Any solution of the Bloch equation depends on three roots of a cubic polynomial that are crucial to the time dependence of the system. The roots are typically only sketched out qualitatively, with no indication of their dependence on the physical parameters of the problem. Degenerate roots, which modify the solutions, have been ignored altogether. Here the roots are obtained explicitly in terms of a single real-valued root that is expressed as a simple function of the system parameters. For the conventional Bloch equation, a simple graphical representation of this root is presented that makes evident the explicit time dependence of the system for each point in the parameter space. Several intuitive, visual models of system dynamics are developed. A Euclidean coordinate system is identified in which any generalized Bloch equation is separable, i.e., the sum of commuting rotation and relaxation operators. The time evolution in this frame is simply a rotation followed by relaxation at modified rates that play a role similar to the standard longitudinal and transverse rates. These rates are functions of the applied field, which

  11. Total phenolic content and in-vitro antioxidant activities from methanolic extract of alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

    Digital Repository Service at National Institute of Oceanography (India)

    Sanaye, S.V.; Pise, N.M.; Pawar, A.P.; Parab, P.P.; Sreepada, R.A.; Pawar, H.B.; Murugan, A.

    Alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785) is one of the heavily traded and expensive ingredient in traditional Chinese medicines and there were no reports on its antioxidant activities Total phenolic content (TPC) and in...

  12. Magneto-optical switching of Bloch surface waves in magnetophotonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Romodina, M.N.; Soboleva, I.V.; Fedyanin, A.A., E-mail: fedyanin@nanolab.phys.msu.ru

    2016-10-01

    Bloch-surface-wave (BSW) excitation controlled by Faraday rotation in one-dimensional magnetophotonic crystals is presented. Dispersion curves of the Bloch surface wave and waveguide modes of magnetophotonic crystals consisting of silicon dioxide and bismuth-substituted yttrium-iron-garnet (Bi:YIG) quarter-wavelength-thick layers are calculated using Berreman's 4×4 transfer matrix method. Enhanced Faraday rotation observed in the magnetophotonic crystals in the spectral vicinity of the BSW resonance enables the magneto-optical switching of BSWs. The excitation of the BSWs at the magnetophotonic crystal surface for p-polarized incident light is induced by magneto-optical activity in the Bi:YIG layers.

  13. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    Science.gov (United States)

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-01-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization. PMID:26238042

  14. Quantum Theory of Conducting Matter Newtonian Equations of Motion for a Bloch Electron

    CERN Document Server

    Fujita, Shigeji

    2007-01-01

    Quantum Theory of Conducting Matter: Newtonian Equations of Motion for a Bloch Electron targets scientists, researchers and graduate-level students focused on experimentation in the fields of physics, chemistry, electrical engineering, and material sciences. It is important that the reader have an understanding of dynamics, quantum mechanics, thermodynamics, statistical mechanics, electromagnetism and solid-state physics. Many worked-out problems are included in the book to aid the reader's comprehension of the subject. The Bloch electron (wave packet) moves by following the Newtonian equation of motion. Under an applied magnetic field B the electron circulates around the field B counterclockwise or clockwise depending on the curvature of the Fermi surface. The signs of the Hall coefficient and the Seebeck coefficient are known to give the sign of the major carrier charge. For alkali metals, both are negative, indicating that the carriers are "electrons." These features arise from the Fermi surface difference...

  15. Modeling Dzyaloshinskii-Moriya Interaction at Transition Metal Interfaces: Constrained Moment versus Generalized Bloch Theorem

    KAUST Repository

    Dong, Yao-Jun

    2017-10-29

    Dzyaloshinskii-Moriya interaction (DMI) at Pt/Co interfaces is investigated theoretically using two different first principles methods. The first one uses the constrained moment method to build a spin spiral in real space, while the second method uses the generalized Bloch theorem approach to construct a spin spiral in reciprocal space. We show that although the two methods produce an overall similar total DMI energy, the dependence of DMI as a function of the spin spiral wavelength is dramatically different. We suggest that long-range magnetic interactions, that determine itinerant magnetism in transition metals, are responsible for this discrepancy. We conclude that the generalized Bloch theorem approach is more adapted to model DMI in transition metal systems, where magnetism is delocalized, while the constrained moment approach is mostly applicable to weak or insulating magnets, where magnetism is localized.

  16. An optimum Hamiltonian for non-Hermitian quantum evolution and the complex Bloch sphere

    Energy Technology Data Exchange (ETDEWEB)

    Nesterov, Alexander I., E-mail: nesterov@cencar.udg.m [Departamento de Fisica, CUCEI, Universidad de Guadalajara, Av. Revolucion 1500, Guadalajara, CP 44420, Jalisco (Mexico)

    2009-09-28

    For a quantum system governed by a non-Hermitian Hamiltonian, we studied the problem of obtaining an optimum Hamiltonian that generates nonunitary transformations of a given initial state into a certain final state in the smallest time tau. The analysis is based on the relationship between the states of the two-dimensional subspace of the Hilbert space spanned by the initial and final states and the points of the two-dimensional complex Bloch sphere.

  17. Reflectors and resonators for high-k bulk Bloch plasmonic waves in multilayer hyperbolic metamaterials

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Lavrinenko, Andrei

    2012-01-01

    We propose proof-of-concept designs of Bragg reflectors and Fabry-Pe´rot resonators for large wave vector waves (Bloch bulk plasmon polaritons) in multilayer metal-dielectric hyperbolic metamaterials. The designs are based on hybrid multilayers having both subwavelength and wavelength......-scale structuring. This multiscale approach is shown to be a promising platform for using bulk plasmonic waves in complex multilayer metamaterials as a new kind of information carriers....

  18. Norm equivalence and composition operators between Bloch/Lipschitz spaces of the ball

    Directory of Open Access Journals (Sweden)

    Stević Stevo

    2006-01-01

    Full Text Available For , let and denote, respectively, the -Bloch and holomorphic -Lipschitz spaces of the open unit ball in . It is known that and are equal as sets when . We prove that these spaces are additionally norm-equivalent, thus extending known results for and the polydisk. As an application, we generalize work by Madigan on the disk by investigating boundedness of the composition operator from to .

  19. Real-time protein aggregation monitoring with a Bloch surface wave-based approach

    Science.gov (United States)

    Santi, Sara; Barakat, Elsie; Descrovi, Emiliano; Neier, Reinhard; Herzig, Hans Peter

    2014-05-01

    The misfolding and aggregation of amyloid proteins has been associated with incurable diseases such as Alzheimer's or Parkinson's disease. In the specific case of Alzheimer's disease, recent studies have shown that cell toxicity is caused by soluble oligomeric forms of aggregates appearing in the early stages of aggregation, rather than by insoluble fibrils. Research on new strategies of diagnosis is imperative to detect the disease prior to the onset of clinical symptoms. Here, we propose the use of an optical method for protein aggregation dynamic studies using a Bloch surface wave based approach. A one dimension photonic crystal made of a periodic stack of silicon oxide and silicon nitride layers is used to excite a Bloch surface wave, which is sensitive to variation of the refractive index of an aqueous solution. The aim is to detect the early dynamic events of protein aggregation and fibrillogenesis of the amyloid-beta peptide Aβ42, which plays a central role in the onset of the Alzheimer's disease. The detection principle relies on the refractive index changes caused by the depletion of the Aβ42 monomer concentration during oligomerization and fibrillization. We demonstrate the efficacy of the Bloch surface wave approach by monitoring in real-time the first crucial steps of Aβ42 oligomerization.

  20. Coherent amplification and noise in gain-enhanced nanoplasmonic metamaterials: a Maxwell-Bloch Langevin approach.

    Science.gov (United States)

    Pusch, Andreas; Wuestner, Sebastian; Hamm, Joachim M; Tsakmakidis, Kosmas L; Hess, Ortwin

    2012-03-27

    Nanoplasmonic metamaterials are an exciting new class of engineered media that promise a range of important applications, such as subwavelength focusing, cloaking, and slowing/stopping of light. At optical frequencies, using gain to overcome potentially not insignificant losses has recently emerged as a viable solution to ultra-low-loss operation that may lead to next-generation active metamaterials. Maxwell-Bloch models for active nanoplasmonic metamaterials are able to describe the coherent spatiotemporal and nonlinear gain-plasmon dynamics. Here, we extend the Maxwell-Bloch theory to a Maxwell-Bloch Langevin approach-a spatially resolved model that describes the light field and noise dynamics in gain-enhanced nanoplasmonic structures. Using the example of an optically pumped nanofishnet metamaterial with an embedded laser dye (four-level) medium exhibiting a negative refractive index, we demonstrate the transition from loss-compensation to amplification and to nanolasing. We observe ultrafast relaxation oscillations of the bright negative-index mode with frequencies just below the THz regime. The influence of noise on mode competition and the onset and magnitude of the relaxation oscillations is elucidated, and the dynamics and spectra of the emitted light indicate that coherent amplification and lasing are maintained even in the presence of noise and amplified spontaneous emission. © 2012 American Chemical Society

  1. Adele Bloch-Bauer (1881-1925): Possible diagnoses for Gustav Klimt's Lady in Gold.

    Science.gov (United States)

    da Mota, Licia Maria H; Neubarth, Fernando; de Carvalho, Jozélio F; Diniz, Leonardo R; Aires, Rodrigo B; Dos Santos-Neto, Leopoldo L

    2016-08-01

    One of the most famous works by the Austrian symbolist painter Gustav Klimt and one of the most widely reproduced works of art worldwide, Adele Bloch-Bauer I which portrays the beautiful wife of Austrian magnate Ferdinand Bloch-Bauer. Adele was the only woman painted by Klimt on more than one occasion. Apart from the beauty and value of the painting, the daring sea of gold that surrounds Adele and the gentle intimacy with which her fragile figure is portrayed have shrouded the history of this painting in mystery. Beyond speculation as to a special bond between artist and model, observation of the painting with a keener, clinical gaze yields evidence of potential illness in the model: facial erythema which, if not produced artificially by makeup, could represent a malar rash; pallor or cyanosis of the hands; and her draped fingers, which seemingly attempt to hide a deformity. This paper seeks to provide a biographical review both of the painter, Gustav Klimt, and of the subject, Adele Bloch-Bauer; to analyse Klimt's two portrayals of her in a search for evidence of a potential intimate relationship between artist and muse and, finally, to compile clinical evidence of possible diagnoses for the Lady in Gold. © The Author(s) 2016.

  2. Bloch oscillations of ultracold atoms and measurement of the fine structure constant; Oscillations de Bloch d'atomes ultrafroids et mesure de la constante de structure fine

    Energy Technology Data Exchange (ETDEWEB)

    Clade, P

    2005-10-15

    From a measurement of the recoil velocity of an atom absorbing a photon, it is possible to deduce a determination of the ratio h/m between the Planck constant and the mass of the atoms and then to deduce a value of the fine structure constant alpha. To do this measurement, we use the technique of Bloch oscillations, which allows us to transfer a large number of recoils to atoms. A velocity sensor, based on velocity selective Raman transition, enables us to measure the momentum transferred to the atoms. A measurement with a statistical uncertainty of 4.4 10{sup -9}, in conjunction with a careful study of systematic effects (5 10{sup -9}), has led us to a determination of alpha with an uncertainty of 6.7 10{sup -9}: {alpha}{sup -1}(Rb) = 137.03599878 (91). This uncertainty is similar to the uncertainty of the best determinations of alpha based on atom interferometry. (author)

  3. Identification of Bloch-modes in hollow-core Photonic Crystal Fiber cladding

    DEFF Research Database (Denmark)

    Couny, F.; Benabid, F.; Roberts, John

    2007-01-01

    length of fiber. A detailed study of the modes near the edges of the band gap shows that it is formed by the influence of three types of resonator: the glass interstitial apex, the silica strut which joins the neighboring apexes, and the air hole. The cladding electromagnetic field which survives......We report on the experimental visualization of the cladding Bloch-modes of a hollow-core photonic crystal fiber. Both spectral and spatial field information is extracted using the approach, which is based on measurement of the near-field and Fresnel-zone that results after propagation over a short...

  4. Maurice Halbwachs e Marc Bloch em torno do conceito de memória coletiva

    Directory of Open Access Journals (Sweden)

    Eliza Bachega Casadei

    2010-05-01

    Full Text Available

    After noting that the concept of “collective memory” has become increasingly important for many areas of Humanities, this paper proposes the study of discussions between the inventor of the term, Maurice Halbwachs and historian Marc Bloch around this theme. Halbwachs was pioneer when he took away the memory of a sphere merely individual and Bloch added the problem of collective memories’ transmission. The purpose of this paper is to rescue this debate and study how it influenced the subsequent developments around the theme.

    A partir da constatação de que o conceito de “memória coletiva” tem se tornado cada vez mais importante para diversas áreas das Ciências Humanas, o presente artigo propõe o estudo da discussão entre o inventor do termo, Maurice Halbwachs e o historiador Marc Bloch em torno desta temática. Ao passo em que Halbwachs estabelece, pioneiramente, um trabalho que retira a memória de uma esfera meramente individual, Bloch acrescenta a problemática da transmissão das lembranças coletivas. O objetivo do presente texto é resgatar esse debate, bem como estudar como ele influenciou nos desdobramentos posteriores em torno do tema.

  5. Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

    DEFF Research Database (Denmark)

    Cartar, William; Mørk, Jesper; Hughes, Stephen

    2017-01-01

    We present a powerful computational approach to simulate the threshold behavior of photonic-crystal quantum-dot (QD) lasers. Using a finite-difference time-domain (FDTD) technique, Maxwell-Bloch equations representing a system of thousands of statistically independent and randomly positioned two...... by matching the cavity quality factors and resonance properties. We also demonstrate how to obtain the correct point-dipole radiative decay rate from Fermi's golden rule, which is captured naturally by the FDTD method. Our numerical simulations predict that the pump threshold plateaus around cavity lengths...

  6. LDRD final report on Bloch Oscillations in two-dimensional nanostructure arrays for high frequency applications.

    Energy Technology Data Exchange (ETDEWEB)

    Lyo, Sungkwun Kenneth; Pan, Wei; Reno, John Louis; Wendt, Joel Robert; Barton, Daniel Lee

    2008-09-01

    We have investigated the physics of Bloch oscillations (BO) of electrons, engineered in high mobility quantum wells patterned into lateral periodic arrays of nanostructures, i.e. two-dimensional (2D) quantum dot superlattices (QDSLs). A BO occurs when an electron moves out of the Brillouin zone (BZ) in response to a DC electric field, passing back into the BZ on the opposite side. This results in quantum oscillations of the electron--i.e., a high frequency AC current in response to a DC voltage. Thus, engineering a BO will yield continuously electrically tunable high-frequency sources (and detectors) for sensor applications, and be a physics tour-de-force. More than a decade ago, Bloch oscillation (BO) was observed in a quantum well superlattice (QWSL) in short-pulse optical experiments. However, its potential as electrically biased high frequency source and detector so far has not been realized. This is partially due to fast damping of BO in QWSLs. In this project, we have investigated the possibility of improving the stability of BO by fabricating lateral superlattices of periodic coupled nanostructures, such as metal grid, quantum (anti)dots arrays, in high quality GaAs/Al{sub x}Ga{sub 1-x}As heterostructures. In these nanostructures, the lateral quantum confinement has been shown theoretically to suppress the optical-phonon scattering, believed to be the main mechanism for fast damping of BO in QWSLs. Over the last three years, we have made great progress toward demonstrating Bloch oscillations in QDSLs. In the first two years of this project, we studied the negative differential conductance and the Bloch radiation induced edge-magnetoplasmon resonance. Recently, in collaboration with Prof. Kono's group at Rice University, we investigated the time-domain THz magneto-spectroscopy measurements in QDSLs and two-dimensional electron systems. A surprising DC electrical field induced THz phase flip was observed. More measurements are planned to investigate this

  7. Optical surface edge Bloch modes: low-loss subwavelength-scale 2D light localization

    CERN Document Server

    Su, Shu-Yu

    2012-01-01

    Edge modes of a finite-size woodpile can appear within a complete bandgap on an edge. The mode area is as small as 0.066 squared half-in-vacuum-wavelengths, and the propagation loss is small. The field maxima occur at a dielectric-vacuum interface, like at a metal-dielectric interface for surface plasmon modes. The edge mode is a subwavelength-scale 2D light localization mode in non-metallic materials. Analysis of two-mode co-directional coupling between identical surface Bloch modes suggests that a large photonic crystal or surface designing would be needed for suppressing the evanescent field coupling in the woodpile.

  8. Motives and algebraic cycles a celebration in honour of Spencer J. Bloch

    CERN Document Server

    Jeu, Rob de; Lewis, James D

    2009-01-01

    Spencer J. Bloch has, and continues to have, a profound influence on the subject of Algebraic K-Theory, Cycles and Motives. This book, which is comprised of a number of independent research articles written by leading experts in the field, is dedicated in his honour, and gives a snapshot of the current and evolving nature of the subject. Some of the articles are written in an expository style, providing a perspective on the current state of the subject to those wishing to learn more about it. Others are more technical, representing new developments and making them especially interesting to res

  9. Proof of an entropy conjecture for Bloch coherent spin states and its generalizations

    DEFF Research Database (Denmark)

    H. Lieb, Elliott; Solovej, Jan Philip

    2014-01-01

    Wehrl used Glauber coherent states to define a map from quantum density matrices to classical phase space densities and conjectured that for Glauber coherent states the mininimum classical entropy would occur for density matrices equal to projectors onto coherent states. This was proved by Lieb...... in 1978 who also extended the conjecture to Bloch SU(2) spin-coherent states for every angular momentum $J$. This conjecture is proved here. We also recall our 1991 extension of the Wehrl map to a quantum channel from $J$ to $K=J+1/2, J+1, ...$, with $K=\\infty$ corresponding to the Wehrl map to classical...

  10. Wannier-Bloch approach to localization in high harmonics generation in solids

    CERN Document Server

    Osika, Edyta N; Ortmann, Lisa; Suárez, Noslen; Pérez-Hernández, Jose Antonio; Szafran, Bartłomiej; Ciappina, Marcelo F; Sols, Fernando; Landsman, Alexandra S; Lewenstein, Maciej

    2016-01-01

    Emission of high-order harmonics from solids provides a new avenue in attosecond science. On one hand, it allows to investigate fundamental processes of the non-linear response of electrons driven by a strong laser pulse in a periodic crystal lattice. On the other hand, it opens new paths toward efficient attosecond pulse generation, novel imaging of electronic wave functions, and enhancement of high-order harmonic generation (HHG) intensity. A key feature of HHG in a solid (as compared to the well-understood phenomena of HHG in an atomic gas) is the delocalization of the process, whereby an electron ionized from one site in the periodic lattice may recombine with any other. Here, we develop an analytic model, based on the localized Wannier wave functions in the valence band and delocalized Bloch functions in the conduction band. This Wannier-Bloch approach assesses the contributions of individual lattice sites to the HHG process, and hence addresses precisely the question of localization of harmonic emission...

  11. Rabi-Bloch oscillations in spatially distributed systems: Temporal dynamics and frequency spectra

    Science.gov (United States)

    Levie, Ilay; Kastner, Raphael; Slepyan, Gregory

    2017-10-01

    We consider one-dimensional chains of two-level quantum systems coupled via tunneling. The chain is driven by the superposition of dc and ac fields in the strong coupling regime. Based on the fundamental principles of electrodynamics and quantum theory, we have developed a generalized model of quantum dynamics for such interactions, free of rotating-wave approximation. The system of equations of motion was studied numerically. We analyzed the dynamics and spectra of the inversion density, dipole current density, and tunneling current density. In the case of resonant interaction with the ac component, the particle dynamics exhibits itself in the oscillatory regime, which may be interpreted as a combination of Rabi and Bloch oscillations with their strong mutual influence. Such scenario for an obliquely incident ac field dramatically differs from the individual picture of both types of oscillations due to the interactions. This effect is counterintuitive because of the existence of markedly different frequency ranges for such two types of oscillations. These dynamics manifest themselves in multiline spectra in different combinations of Rabi and Bloch frequencies. The effect is promising as a framework of a new type of spectroscopy in nanoelectronics and electrical control of nanodevices.

  12. Solving the Bloch equation with periodic excitation using harmonic balancing: application to Rabi modulated excitation.

    Science.gov (United States)

    Tahayori, Bahman; Johnston, Leigh A; Layton, Kelvin J; Farrell, Peter M; Mareels, Iven M Y

    2015-10-01

    In waveform design for magnetic resonance applications, periodic continuous-wave excitation offers potential advantages that remain largely unexplored because of a lack of understanding of the Bloch equation with periodic continuous-wave excitations. Using harmonic balancing techniques the steady state solutions of the Bloch equation with periodic excitation can be effectively solved. Moreover, the convergence speed of the proposed series approximation is such that a few terms in the series expansion suffice to obtain a very accurate description of the steady state solution. The accuracy of the proposed analytic approximate series solution is verified using both a simulation study as well as experimental data derived from a spherical phantom with doped water under continuous-wave excitation. Typically a five term series suffices to achieve a relative error of less than one percent, allowing for a very effective and efficient analytical design process. The opportunities for Rabi frequency modulated continuous-wave form excitation are then explored, based on a comparison with steady state free precession pulse sequences.

  13. Transport of Photonic Bloch Wave in Arrayed Two-Level Atoms.

    Science.gov (United States)

    Chang, Chih-Chun; Lin, Lee; Chen, Guang-Yin

    2018-01-24

    In a quantum system of arrayed two-level atoms interacting with light, the interacted (dressed) photon is propagating in a periodic medium and its eigenstate ought to be of Bloch type with lattice symmetry. As the energy of photon is around the spacing between the two atomic energy levels, the photon will be absorbed and is not in the propagating mode but the attenuated mode. Therefore an energy gap exists in the dispersion relation of the photonic Bloch wave of dressed photon in addition to the nonlinear behaviors due to atom-light interactions. There follows several interesting results which are distinct from those obtained through a linear dispersion relation of free photon. For example, slow light can exist, the density of state of dressed photon is non-Lorentzian and is very large around the energy gap; the Rabi oscillations become monotonically decreasing in some cases; and besides the superradiance occurs at long wavelengths, the spontaneous emission is also very strong near the energy gap because of the high density of state.

  14. Bloch Waves in Minimal Landau Gauge and the Infinite-Volume Limit of Lattice Gauge Theory.

    Science.gov (United States)

    Cucchieri, Attilio; Mendes, Tereza

    2017-05-12

    By exploiting the similarity between Bloch's theorem for electrons in crystalline solids and the problem of Landau gauge fixing in Yang-Mills theory on a "replicated" lattice, we show that large-volume results can be reproduced by simulations performed on much smaller lattices. This approach, proposed by Zwanziger [Nucl. Phys. B412, 657 (1994)NUPBBO0550-321310.1016/0550-3213(94)90396-4], corresponds to taking the infinite-volume limit for Landau-gauge field configurations in two steps: first for the gauge transformation alone, while keeping the lattice volume finite, and second for the gauge-field configuration itself. The solutions to the gauge-fixing condition are then given in terms of Bloch waves. Applying the method to data from Monte Carlo simulations of pure SU(2) gauge theory in two and three space-time dimensions, we are able to evaluate the Landau-gauge gluon propagator for lattices of linear extent up to 16 times larger than that of the simulated lattice. This approach is reminiscent of the Fisher-Ruelle construction of the thermodynamic limit in classical statistical mechanics.

  15. Anomalous diffusion expressed through fractional order differential operators in the Bloch-Torrey equation.

    Science.gov (United States)

    Magin, Richard L; Abdullah, Osama; Baleanu, Dumitru; Zhou, Xiaohong Joe

    2008-02-01

    Diffusion weighted MRI is used clinically to detect and characterize neurodegenerative, malignant and ischemic diseases. The correlation between developing pathology and localized diffusion relies on diffusion-weighted pulse sequences to probe biophysical models of molecular diffusion-typically exp[-(bD)]-where D is the apparent diffusion coefficient (mm(2)/s) and b depends on the specific gradient pulse sequence parameters. Several recent studies have investigated the so-called anomalous diffusion stretched exponential model-exp[-(bD)(alpha)], where alpha is a measure of tissue complexity that can be derived from fractal models of tissue structure. In this paper we propose an alternative derivation for the stretched exponential model using fractional order space and time derivatives. First, we consider the case where the spatial Laplacian in the Bloch-Torrey equation is generalized to incorporate a fractional order Brownian model of diffusivity. Second, we consider the case where the time derivative in the Bloch-Torrey equation is replaced by a Riemann-Liouville fractional order time derivative expressed in the Caputo form. Both cases revert to the classical results for integer order operations. Fractional order dynamics derived for the first case were observed to fit the signal attenuation in diffusion-weighted images obtained from Sephadex gels, human articular cartilage and human brain. Future developments of this approach may be useful for classifying anomalous diffusion in tissues with developing pathology.

  16. Bloch Waves in Minimal Landau Gauge and the Infinite-Volume Limit of Lattice Gauge Theory

    Science.gov (United States)

    Cucchieri, Attilio; Mendes, Tereza

    2017-05-01

    By exploiting the similarity between Bloch's theorem for electrons in crystalline solids and the problem of Landau gauge fixing in Yang-Mills theory on a "replicated" lattice, we show that large-volume results can be reproduced by simulations performed on much smaller lattices. This approach, proposed by Zwanziger [Nucl. Phys. B412, 657 (1994), 10.1016/0550-3213(94)90396-4], corresponds to taking the infinite-volume limit for Landau-gauge field configurations in two steps: first for the gauge transformation alone, while keeping the lattice volume finite, and second for the gauge-field configuration itself. The solutions to the gauge-fixing condition are then given in terms of Bloch waves. Applying the method to data from Monte Carlo simulations of pure SU(2) gauge theory in two and three space-time dimensions, we are able to evaluate the Landau-gauge gluon propagator for lattices of linear extent up to 16 times larger than that of the simulated lattice. This approach is reminiscent of the Fisher-Ruelle construction of the thermodynamic limit in classical statistical mechanics.

  17. Nonlinear Bloch waves and current states of exciton-polariton condensates

    Science.gov (United States)

    Chestnov, I. Yu.; Yulin, A. V.; Alodjants, A. P.; Egorov, O. A.

    2016-09-01

    The formation of nonlinear Bloch states in open driven-dissipative systems of exciton-polaritons loaded into a weak-contrast 1D periodic lattice is studied numerically and analytically. The condensate is described within the framework of mean-field theory by the coupled equations for the order parameter and for the density of incoherent excitons. The stationary nonlinear solutions having the structure of Bloch waves are studied in detail. It is shown that there is a bifurcation leading to the appearance of a family of essentially nonlinear states. The special feature of these solutions is that its current does not vanish when the quasimomentum of the state approaches the values equal to half of the lattice constant. To explain the bifurcations found in numerical simulations a simple perturbative approach is developed. The stability of the nonlinear states is examined by linear spectral analysis and by direct numerical simulations. An experimental scheme allowing the observation of the discussed nonlinear current states is suggested and studied by numerical simulations.

  18. Wannier-Bloch Approach to Localization in High-Harmonics Generation in Solids

    Directory of Open Access Journals (Sweden)

    Edyta N. Osika

    2017-05-01

    Full Text Available Emission of high-order harmonics from solids provides a new avenue in attosecond science. On the one hand, it allows us to investigate fundamental processes of the nonlinear response of electrons driven by a strong laser pulse in a periodic crystal lattice. On the other hand, it opens new paths toward efficient attosecond pulse generation, novel imaging of electronic wave functions, and enhancement of high-order harmonic-generation (HHG intensity. A key feature of HHG in a solid (as compared to the well-understood phenomenon of HHG in an atomic gas is the delocalization of the process, whereby an electron ionized from one site in the periodic lattice may recombine in any other. Here, we develop an analytic model, based on the localized Wannier wave functions in the valence band and delocalized Bloch functions in the conduction band. This Wannier-Bloch approach assesses the contributions of individual lattice sites to the HHG process and hence precisely addresses the question of localization of harmonic emission in solids. We apply this model to investigate HHG in a ZnO crystal for two different orientations, corresponding to wider and narrower valence and conduction bands, respectively. Interestingly, for narrower bands, the HHG process shows significant localization, similar to harmonic generation in atoms. For all cases, the delocalized contributions to HHG emission are highest near the band-gap energy. Our results pave the way to controlling localized contributions to HHG in a solid crystal.

  19. Ising and Bloch domain walls in a two-dimensional parametrically driven Ginzburg-Landau equation model with nonlinearity management

    DEFF Research Database (Denmark)

    Gaididei, Yu. B.; Christiansen, Peter Leth

    2008-01-01

    We study a parametrically driven Ginzburg-Landau equation model with nonlinear management. The system is made of laterally coupled long active waveguides placed along a circumference. Stationary solutions of three kinds are found: periodic Ising states and two types of Bloch states, staggered and...

  20. A 2D multi-term time and space fractional Bloch-Torrey model based on bilinear rectangular finite elements

    Science.gov (United States)

    Qin, Shanlin; Liu, Fawang; Turner, Ian W.

    2018-03-01

    The consideration of diffusion processes in magnetic resonance imaging (MRI) signal attenuation is classically described by the Bloch-Torrey equation. However, many recent works highlight the distinct deviation in MRI signal decay due to anomalous diffusion, which motivates the fractional order generalization of the Bloch-Torrey equation. In this work, we study the two-dimensional multi-term time and space fractional diffusion equation generalized from the time and space fractional Bloch-Torrey equation. By using the Galerkin finite element method with a structured mesh consisting of rectangular elements to discretize in space and the L1 approximation of the Caputo fractional derivative in time, a fully discrete numerical scheme is derived. A rigorous analysis of stability and error estimation is provided. Numerical experiments in the square and L-shaped domains are performed to give an insight into the efficiency and reliability of our method. Then the scheme is applied to solve the multi-term time and space fractional Bloch-Torrey equation, which shows that the extra time derivative terms impact the relaxation process.

  1. Permittivity and Permeability for Floquet-Bloch Space Harmonics in Infinite 1D Magneto-Dielectric Periodic Structures

    DEFF Research Database (Denmark)

    Breinbjerg, Olav; Yaghjian, Arthur D.

    2014-01-01

    -Bloch space harmonics. We discuss how space harmonic permittivity and permeability can be expressed in seemingly different though equivalent forms, and we investigate these parameters of the zeroeth order space harmonic for a particular 1D periodic structure that is based on a previously reported 3D periodic...

  2. Notes on the genus Amphiprion Bloch & Schneider, 1801 (Teleostei: Pomacentridae) and its host sea anemones in the Seychelles

    NARCIS (Netherlands)

    Hartog, den J.C.

    1997-01-01

    The genus Amphiprion Bloch & Schneider, 1801, is represented in the Seychelles by two species, A. akallopisos Bleeker, 1853, and the endemic A. fuscocaudatus Allen, 1972. Throughout its distributional range Amphiprion akallopisos has exclusively been recorded to associate with the clownfish anemones

  3. Boundedness and compactness of a new product-type operator from a general space to Bloch-type spaces

    Directory of Open Access Journals (Sweden)

    Stevo Stević

    2016-09-01

    Full Text Available Abstract We characterize the boundedness and compactness of a product-type operator, which, among others, includes all the products of the single composition, multiplication, and differentiation operators, from a general space to Bloch-type spaces. We also give some upper and lower bounds for the norm of the operator.

  4. Desenvolvimento morfológico das larvas de Hoplias lacerdae Miranda Ribeiro, 1908 (Characiformes, Erythrinidae, da eclosão até a metamorfose, relacionado com a capacidade de capturar alimento exógeno

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Reis Raposo Maciel

    2009-06-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p103 Para a realização deste trabalho foram utilizados 510 exemplares de Hoplias lacerdae, com um a 30 dias após a eclosão, com o objetivo de estudar as características morfológicas, mesoscópicas, que capacitam essa espécie, nas fases iniciais do seu desenvolvimento, a apresentarem estruturas adaptadas para se locomoverem e capturarem alimento exógeno. As larvas vitelínicas com 11 dias após a eclosão têm potencialidade para capturar alimento exógeno, ou seja, presas, mesmo antes da absorção total do vitelo, o que acontece com 12 dias. Nesta fase apresentam: boca aberta com um dia após a eclosão e posição terminal aos quatro dias; aos sete dias demonstram flexão da notocorda, proporcionando maior eficiência locomotora, bem como apresenta neste período nadadeiras peitorais desenvolvidas, as quais facilitam o equilíbrio e direcionamento na coluna d’água; e aos oito dias visualizou-se a formação das nadadeiras dorsal e anal, porém as nadadeiras pélvicas foram visualizadas aos 11 dias.

  5. The Bloch wave operator: generalizations and applications: Part I. The time-independent case

    Energy Technology Data Exchange (ETDEWEB)

    Killingbeck, John P [Mathematics Department, University of Hull, Hull HU6 7RX (United Kingdom); Jolicard, Georges [Observatoire de Besancon (UMR-CNRS 6091), Universite de Franche-Comte, 41 bis, Avenue de l' Observatoire, 25000 Besancon (France)

    2003-05-23

    This is part 1 of a two-part review on wave operator theory and methods. The basic theory of the time-independent wave operator is presented in terms of partitioned matrix theory for the benefit of general readers, with a discussion of the links between the matrix and projection operator approaches. The matrix approach is shown to lead to simple derivations of the wave operators and effective Hamiltonians of Loewdin, Bloch, Des Cloizeaux and Kato as well as to some associated variational forms. The principal approach used throughout stresses the solution of the nonlinear equation for the reduced wave operator, leading to the construction of the effective Hamiltonians of Bloch and of Des Cloizeaux. Several mathematical techniques which are useful in implementing this approach are explained, some of them being relatively little known in the area of wave operator calculations. The theoretical discussion is accompanied by several specimen numerical calculations which apply the described techniques to a selection of test matrices taken from the previous literature on wave operator methods. The main emphasis throughout is on the use of numerical methods which use iterative or perturbation algorithms, with simple Pade approximant methods being found sufficient to deal with most of the cases of divergence which are encountered. The use of damping factors and relaxation parameters is found to be effective in stabilizing calculations which use the energy-dependent effective Hamiltonian of Loewdin. In general the computations suggest that the numerical applications of the nonlinear equation for the reduced wave operator are best carried out with the equation split into a pair of equations in which the Bloch effective Hamiltonian appears as a separate entity. The presentation of the theoretical and computational details throughout is accompanied by references to and discussion of many works which have used wave operator methods in physics, chemistry and engineering. Some of

  6. Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

    Science.gov (United States)

    Cartar, William; Mørk, Jesper; Hughes, Stephen

    2017-08-01

    We present a powerful computational approach to simulate the threshold behavior of photonic-crystal quantum-dot (QD) lasers. Using a finite-difference time-domain (FDTD) technique, Maxwell-Bloch equations representing a system of thousands of statistically independent and randomly positioned two-level emitters are solved numerically. Phenomenological pure dephasing and incoherent pumping is added to the optical Bloch equations to allow for a dynamical lasing regime, but the cavity-mediated radiative dynamics and gain coupling of each QD dipole (artificial atom) is contained self-consistently within the model. These Maxwell-Bloch equations are implemented by using Lumerical's flexible material plug-in tool, which allows a user to define additional equations of motion for the nonlinear polarization. We implement the gain ensemble within triangular-lattice photonic-crystal cavities of various length N (where N refers to the number of missing holes), and investigate the cavity mode characteristics and the threshold regime as a function of cavity length. We develop effective two-dimensional model simulations which are derived after studying the full three-dimensional passive material structures by matching the cavity quality factors and resonance properties. We also demonstrate how to obtain the correct point-dipole radiative decay rate from Fermi's golden rule, which is captured naturally by the FDTD method. Our numerical simulations predict that the pump threshold plateaus around cavity lengths greater than N =9 , which we identify as a consequence of the complex spatial dynamics and gain coupling from the inhomogeneous QD ensemble. This behavior is not expected from simple rate-equation analysis commonly adopted in the literature, but is in qualitative agreement with recent experiments. Single-mode to multimode lasing is also observed, depending on the spectral peak frequency of the QD ensemble. Using a statistical modal analysis of the average decay rates, we also

  7. A utopia concreta e o ainda-não-consciente na obra de Ernst Bloch

    OpenAIRE

    Viana, Francisco Antonio Marques

    2015-01-01

    O pensamento de Ernst Bloch é complexo, sua obra é extensa e, em geral, tem sido analisado pelas suas feições messiânicas, utópicas, místicas ou ainda pela sua possível repercussão na América Latina e pelo ângulo da esperança. Esta tese, investiga a filosofia blochiana como fonte de renovação e extensão do marxismo, em dois momentos interligados a uma mesma ideia: a revolução socialista, iluminada pela libertação do homem do modo de produção capitalista e a construção da vida melhor. O primei...

  8. Sub- and superluminal kink-like waves in the kinetic limit of Maxwell-Bloch equations

    Energy Technology Data Exchange (ETDEWEB)

    Janowicz, Maciej [Instytut Fizyki Polskiej Akademii Nauk, Aleja Lotnikow 32/46, 02-668 Warszawa (Poland); Holthaus, Martin, E-mail: mjanow@ifpan.edu.pl [Institut fuer Physik, Carl von Ossietzky Universitaet, D-26111 Oldenburg (Germany)

    2011-01-14

    Running-wave solutions to three systems of partial differential equations describing wave propagation in atomic media in the kinetic limit have been obtained. Those systems include approximations to (i) standard two-level Maxwell-Bloch equations; (ii) equations describing processes with saturated absorption in three-level systems and (iii) equations describing processes with reversed saturation in four-level systems. It has been shown that in all three cases kink-like solitary waves can emerge if the dynamical equation for the intensity includes a linear contribution to the Lambert-Beer law. Those solitary waves can propagate with either sub- or superluminal velocity of the edge of the kink, and in a direction which can be either the same as or opposite to that of the carrier wave. In addition, simple qualitative information about the behaviour of waves near the wavefronts has been obtained.

  9. Experimental demonstration of critical coupling of whispering gallery mode cavities on a Bloch surface wave platform.

    Science.gov (United States)

    Vosoughi Lahijani, B; Badri Ghavifekr, H; Dubey, R; Kim, M-S; Vartiainen, I; Roussey, M; Herzig, H P

    2017-12-15

    We experimentally demonstrate critical coupling of whispering gallery mode (WGM) disk resonators implemented on a Bloch surface wave platform using scanning near-field optical microscopy. The studied structure is a 60 nm thick TiO2 WGM disk cavity (radius of 100 μm) operating within the C-band telecommunication wavelength. An extinction ratio of 26 dB and a quality factor of 2200 are measured. Such a high extinction ratio verifies the critical coupling of the WGM resonator. This result paves the way to planar optical signal processing devices based on the proposed geometry, for which a critical coupling condition is a guarantee of optimum performance.

  10. Dynamics of Peregrine combs and Peregrine walls in an inhomogeneous Hirota and Maxwell-Bloch system

    Science.gov (United States)

    Wang, Lei; Wang, Zi-Qi; Sun, Wen-Rong; Shi, Yu-Ying; Li, Min; Xu, Min

    2017-06-01

    Under investigation in this paper is an inhomogeneous Hirota-Maxwell-Bloch (IHMB) system which can describe the propagation of optical solitons in an erbium-doped optical fiber. The breather multiple births (BMBs) are derived with periodically varying group velocity dispersion (GVD) coefficients. Under large periodic modulations in the GVD coefficient of IHMB system, the Peregrine comb (PC) solution is produced, which can be viewed as the limiting case of the BMBs. When the amplitude of the modulation satisfies a special condition, the Peregrine wall (PW) that can be regarded as an intermediate state between rogue wave and PC is obtained. The effects of the third-order dispersion on the spatiotemporal characteristics of PCs and PWs are studied. Our results may be useful for the experimental control and manipulation of the formation of generalized Peregrine rogue waves in inhomogeneous erbium-doped optical fiber.

  11. Bloch surface waves confined in one dimension with a single polymeric nanofibre

    Science.gov (United States)

    Wang, Ruxue; Xia, Hongyan; Zhang, Douguo; Chen, Junxue; Zhu, Liangfu; Wang, Yong; Yang, Erchan; Zang, Tianyang; Wen, Xiaolei; Zou, Gang; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

    2017-02-01

    Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor-memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes.

  12. Optical Bloch oscillation and Zener tunneling in the fractional Schrödinger equation.

    Science.gov (United States)

    Zhang, Yiqi; Wang, Rong; Zhong, Hua; Zhang, Jingwen; Belić, Milivoj R; Zhang, Yanpeng

    2017-12-19

    We demonstrate optical Bloch oscillation (OBO) and optical Zener tunneling (OZT) in the fractional Schrödinger equation (FSE) with periodic and linear potentials, numerically and theoretically. We investigate in parallel the regular Schrödinger equation and the FSE, by adjusting the Lévy index, and expound the differences between the two. We find that the spreading of the OBO decreases in the fractional case, due to the diminishing band width. Increasing the transverse force, due to the linear potential, leads to the appearance of OZT, but this process is suppressed in the FSE. Our results indicate that the adjustment of the Lévy index can effectively control the emergence of OBO and OZT, which can inspire new ideas in the design of optical switches and interconnects.

  13. Galerkin finite element method for two-dimensional space and time fractional Bloch-Torrey equation

    Science.gov (United States)

    Zhao, Yue; Bu, Weiping; Zhao, Xuan; Tang, Yifa

    2017-12-01

    In this paper, we consider the Galerkin finite element method for the two-dimensional space and time fractional Bloch-Torrey equation (2D-STFBTE). Utilizing the L 2 -1σ formula to discretize temporal Caputo derivative, we obtain the local truncation error with O (τ 3 - α) in the temporal direction, where α is the order of time fractional derivative. Furthermore, the semi-discrete form for the problem is given and, the stability and convergence of the semi-discrete variational formulation are rigorously proved in L2 norm and fractional norm respectively. Then, we derive a fully discrete scheme for the 2D-STFBTE and investigate its convergence theoretically. Finally, extensive numerical results based on linear piecewise polynomials verify the theoretical results and show the effectiveness of the proposed scheme.

  14. The Harmonic Bloch and Besov Spaces on the Real Unit Ball by an Oscillation

    Directory of Open Access Journals (Sweden)

    Xi Fu

    2016-01-01

    Full Text Available Let B be the real unit ball in Rn and f∈CN(B. Given a multi-index m=(m1,…,mn of nonnegative integers with |m|=N, we set the quantity supx∈B,y∈E(x,r,x≠y(1-|x|2α(1-|y|2β|∂mf(x-∂mf(y|/|x-y|γ[x,y]1-γ,  x≠y, where 0≤γ≤1 and α+β=N+1. In terms of it, we characterize harmonic Bloch and Besov spaces on the real unit ball. This generalizes the main results of Yoneda, 2002, into real harmonic setting.

  15. A Bloch modal approach for engineering waveguide and cavity modes in two-dimensional photonic crystals

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    -normal modes. As opposed to spatial discretization methods like the nite-dierence time-domain method and the nite element method, the present approach satises automatically the outgoing wave boundary condition in the propagation direction which represents a signicant advantage of our new method. The scheme......In open nanophotonic structures, the natural modes are so-called quasi-normal modes satisfying an outgoing wave boundary condition. We present a new scheme based on a modal expansion technique, a scattering matrix approach and Bloch modes of periodic structures for determining these quasi...... uses no external excitation and determines the quasi-normal modes as unity eigenvalues of the cavity roundtrip matrix. We demonstrate the method and the quasi-normal modes for two types of two-dimensional photonic crystal structures, and discuss the quasi-normal mode eld distributions and Q...

  16. Sub-cycle control of terahertz high-harmonic generation by dynamical Bloch oscillations

    CERN Document Server

    Schubert, O; Langer, F; Urbanek, B; Lange, C; Huttner, U; Golde, D; Meier, T; Kira, M; Koch, S W; Huber, R

    2016-01-01

    Ultrafast charge transport in strongly biased semiconductors is at the heart of highspeed electronics, electro-optics, and fundamental solid-state physics. Intense light pulses in the terahertz (THz) spectral range have opened fascinating vistas: Since THz photon energies are far below typical electronic interband resonances, a stable electromagnetic waveform may serve as a precisely adjustable bias. Novel quantum phenomena have been anticipated for THz amplitudes reaching atomic field strengths. We exploit controlled THz waveforms with peak fields of 72 MV/cm to drive coherent interband polarization combined with dynamical Bloch oscillations in semiconducting gallium selenide. These dynamics entail the emission of phase-stable high-harmonic transients, covering the entire THz-to-visible spectral domain between 0.1 and 675 THz. Quantum interference of different ionization paths of accelerated charge carriers is controlled via the waveform of the driving field and explained by a quantum theory of inter- and in...

  17. A Bloch-Torrey Equation for Diffusion in a Deforming Media

    Energy Technology Data Exchange (ETDEWEB)

    Rohmer, Damien; Gullberg, Grant T.

    2006-12-29

    Diffusion Tensor Magnetic Resonance Imaging (DTMRI)technique enables the measurement of diffusion parameters and therefore,informs on the structure of the biological tissue. This technique isapplied with success to the static organs such as brain. However, thediffusion measurement on the dynamically deformable organs such as thein-vivo heart is a complex problem that has however a great potential inthe measurement of cardiac health. In order to understand the behavior ofthe Magnetic Resonance (MR)signal in a deforming media, the Bloch-Torreyequation that leads the MR behavior is expressed in general curvilinearcoordinates. These coordinates enable to follow the heart geometry anddeformations through time. The equation is finally discretized andpresented in a numerical formulation using implicit methods, in order toget a stable scheme that can be applied to any smooth deformations.Diffusion process enables the link between the macroscopic behavior ofmolecules and themicroscopic structure in which they evolve. Themeasurement of diffusion in biological tissues is therefore of majorimportance in understanding the complex underlying structure that cannotbe studied directly. The Diffusion Tensor Magnetic ResonanceImaging(DTMRI) technique enables the measurement of diffusion parametersand therefore provides information on the structure of the biologicaltissue. This technique has been applied with success to static organssuch as the brain. However, diffusion measurement of dynamicallydeformable organs such as the in-vivo heart remains a complex problem,which holds great potential in determining cardiac health. In order tounderstand the behavior of the magnetic resonance (MR) signal in adeforming media, the Bloch-Torrey equation that defines the MR behavioris expressed in general curvilinear coordinates. These coordinates enableus to follow the heart geometry and deformations through time. Theequation is finally discretized and presented in a numerical formulationusing

  18. Anachronism in the writing of History: ¿Error or Possibility? Some reflections about the concept of time in Carlo Ginzburg, Marc Bloch and Georges Didi-Huberman

    National Research Council Canada - National Science Library

    Maria Eugenia Chaves Maldonado

    2016-01-01

    In his unfinished and posthumously published book Apologie pour l’histoire, Marc Bloch bestowed on future historians a seminal legacy of critical reflections on the concept of time as the object of historical analysis...

  19. An Optomechanical Elevator: Transport of a Bloch Oscillating Bose–Einstein Condensate up and down an Optical Lattice by Cavity Sideband Amplification and Cooling

    Directory of Open Access Journals (Sweden)

    B. Prasanna Venkatesh

    2015-12-01

    Full Text Available In this paper we give a new description, in terms of optomechanics, of previous work on the problem of an atomic Bose–Einstein condensate interacting with the optical lattice inside a laser-pumped optical cavity and subject to a bias force, such as gravity. An atomic wave packet in a tilted lattice undergoes Bloch oscillations; in a high-finesse optical cavity the backaction of the atoms on the light leads to a time-dependent modulation of the intracavity lattice depth at the Bloch frequency which can in turn transport the atoms up or down the lattice. In the optomechanical picture, the transport dynamics can be interpreted as a manifestation of dynamical backaction-induced sideband damping/amplification of the Bloch oscillator. Depending on the sign of the pump-cavity detuning, atoms are transported either with or against the bias force accompanied by an up- or down-conversion of the frequency of the pump laser light. We also evaluate the prospects for using the optomechanical Bloch oscillator to make continuous measurements of forces by reading out the Bloch frequency. In this context, we establish the significant result that the optical spring effect is absent and the Bloch frequency is not modified by the backaction.

  20. Simulação de sinais de RMN através das equações de Bloch

    Directory of Open Access Journals (Sweden)

    Tiago Bueno Moraes

    2014-01-01

    Full Text Available The aim of this paper was to present a simple and fast way of simulating Nuclear Magnetic Resonance signals using the Bloch equations. These phenomenological equations describe the classical behavior of macroscopic magnetization and are easily simulated using rotation matrices. Many NMR pulse sequences can be simulated with this formalism, allowing a quantitative description of the influence of many experimental parameters. Finally, the paper presents simulations of conventional sequences such as Single Pulse, Inversion Recovery, Spin Echo and CPMG.

  1. Comment on ``Enhanced transmission of light through a gold film due to excitation of standing surface-plasmon Bloch waves"

    OpenAIRE

    Weiner, J.

    2007-01-01

    The purpose of this comment is first to correct a misapprehension of the role played by composite wave diffraction on surface-wave generation at subwavelength structures and second to point out that periodic Bloch structures are unnecessary for the efficient production of the surface plasmon polariton (SPP) guided mode either as traveling or standing waves. Guided surface waves originate from simple slit or groove edges illuminated under normal incidence, and one-dimensional (1-D) surface cav...

  2. The Bloch wave operator: generalizations and applications: II. The time-dependent case

    Energy Technology Data Exchange (ETDEWEB)

    Jolicard, Georges [Observatoire de Besancon (UMR-CNRS 6091), Universite de Franche-Comte, 41 bis, Avenue de l' Observatoire, 25000 Besancon (France); Killingbeck, John P [Observatoire de Besancon (UMR-CNRS 6091), Universite de Franche-Comte, 41 bis, Avenue de l' Observatoire, 25000 Besancon (France); Mathematics Department, University of Hull, Hull HU6 7RX (United Kingdom)

    2003-10-10

    Part II of the review shows how the stationary Bloch wave operator of part I can be suitably modified to give a time-dependent wave operator. This operator makes it possible to use a relatively small active space in order to describe the dynamical processes which occur in quantum mechanical systems which have a time-dependent Hamiltonian. A close study is made of the links between the time-dependent and time-independent wave operators at the adiabatic limit; the analysis clarifies the way in which the wave operator formalism allows the time evolution of a system or a wave packet to be described in terms of a fast evolution inside the active space together with weak transitions out of this space which can be treated by perturbation methods. Two alternative wave operator equations of motion are derived and analysed. The first one is a non-linear differential equation in the usual Hilbert space; the second one is a differential equation in an extended Hilbert space with an extra time variable added and becomes equivalent to the usual Bloch equation when the Floquet Hamiltonian is taken in place of the ordinary Hamiltonian. A study is made of the close relationships between the time-dependent wave operator formalism, the Floquet theory and the (t, t') theory. Some original methods of solution of the two forms of wave operator equation are proposed and lead to new techniques of integration for the time-dependent Schroedinger equation (e.g., the generalized Green equation procedure). Mixed procedures involving both the time-independent and time-dependent wave operators are shown to be applicable to the internal eigenstate problem for large complex matrices. A detailed account is given of the description of inelastic and photoreactive processes by means of the time-dependent wave operator formalism, with particular attention to laser-molecule interactions. The emphasis is on projection operator techniques, with special attention being given to the method of selection

  3. Quantum transport and the Wigner distribution function for Bloch electrons in spatially homogeneous electric and magnetic fields

    Science.gov (United States)

    Iafrate, G. J.; Sokolov, V. N.; Krieger, J. B.

    2017-10-01

    The theory of Bloch electron dynamics for carriers in homogeneous electric and magnetic fields of arbitrary time dependence is developed in the framework of the Liouville equation. The Wigner distribution function (WDF) is determined from the single-particle density matrix in the ballistic regime, i.e., collision effects are excluded. In the theory, the single-particle transport equation is established with the electric field described in the vector potential gauge, and the magnetic field is treated in the symmetric gauge. No specific assumptions are made concerning the form of the initial distribution in momentum or configuration space. The general approach is to employ the accelerated Bloch state representation (ABR) as a basis so that the dependence upon the electric field, including multiband Zener tunneling, is treated exactly. Further, in the formulation of the WDF, we transform to a new set of variables so that the final WDF is gauge invariant and is expressed explicitly in terms of the position, kinetic momentum, and time. The methodology for developing the WDF is illustrated by deriving the exact WDF equation for free electrons in homogeneous electric and magnetic fields resulting in the same form as given by the collisionless Boltzmann transport equation (BTE). The methodology is then extended to the case of electrons described by an effective Hamiltonian corresponding to an arbitrary energy band function; the exact WDF equation results for the effective Hamiltonian case are shown to approximate the free electron results when taken to second order in the magnetic field. As a corollary, in these cases, it is shown that if the WDF is a wave packet, then the time rate of change of the electron quasimomentum is given by the Lorentz force. In treating the problem of Bloch electrons in a periodic potential in the presence of homogeneous electric and magnetic fields, the methodology for deriving the WDF reveals a multiband character due to the inherent nature of

  4. Cytotoxic and genotoxic affects of acid mine drainage on fish Channa punctata (Bloch).

    Science.gov (United States)

    Talukdar, B; Kalita, H K; Basumatary, S; Saikia, D J; Sarma, D

    2017-10-01

    The investigation deals with the effects of Acid Mine Drainage (AMD) of coal mine on fish Channa punctata (Bloch) by examining the incidence of haematological, morphological, histological changes and DNA fragmentation in tissues of C. punctata in laboratory condition. For this study fishes were exposed to 10% of AMD for a period of 30 days. The fusion of the primary and secondary gill lamellae, distortion, loss of alignment, deposition of worn out tissues and mucous on the surface of the lamella in the gills; degeneration of morphological architecture, loss of alignment of tubules, mucous deposition in the kidney; cellular damage, cellular necrosis, extraneous deposition on the surface, pore formation in the liver are some important changes detected by scanning electron microscopy. Fishes of AMD treated group showed gradual significant decrease in TEC, Hb and, increase in TLC and DLC as compared to that of the control. DNA fragmentation observed in kidney of fishes from treated group indicates an intricate pollutant present in the AMD. The high incidence of morphological and histological alterations, haematological changes along with DNA breakage in C. punctata is an evidence of the cytotoxic and genotoxic potential of AMD of coal mines. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Establishment of a cell line from kidney of seabass, Lates calcarifer (Bloch

    Directory of Open Access Journals (Sweden)

    Phromkunthong, W.

    2003-01-01

    Full Text Available Primary cell culture from caudal fin and kidney of seabass (Lates calcarifer Bloch using tissue explant method were cultured in three different medias with various salt concentrations. Only seabass kidney (SK cells grew well in Leibovitze's-15 medium containing 8 g/l of NaCl supplemented with 10 % fetal bovine serum at an optimum temperature of 25 oC. Over a period of 24 months, SK cells were subcultured over than 75 passages and exhibited epithelial-like cells. The chromosome number of SK cells was 42. The cells were found to be free from bacterial, fungal and mycoplasma contamination. Seabass cells can be kept at -80 oC and/or in liquid nitrogen (-196 oC for at least 24 months with a survival rate of 83.20 and 74.50 %, respectively. Nine fish viruses were tested for their infectivity and this SK cells were susceptible to sand goby virus (SGV, chub reovirus (CRV, snake-head rhabdovirus (SHRV, red seabream iridovirus (RSIV, seabass iridovirus (SIV and grouper iridovirus-2 (GIV-2.

  6. Exact solutions to the fractional time-space Bloch-Torrey equation for magnetic resonance imaging

    Science.gov (United States)

    Bueno-Orovio, Alfonso; Burrage, Kevin

    2017-11-01

    The quantification of anomalous diffusion is increasingly being recognised as an advanced modality of analysis for the evaluation of tissue microstructure in magnetic resonance imaging (MRI). One powerful framework to account for anomalous diffusion in biological and structurally heterogeneous tissues is the use of diffusion operators based on fractional calculus theory, which generalises the physical principles of standard diffusion in homogeneous media. However, their non-locality makes analytical solutions often unavailable, limiting the applicability of these modelling and analysis techniques. In this paper, we derive compact analytical signal decays for practical MRI sequences in the anisotropic fractional Bloch-Torrey setting, as described by the space fractional Laplacian and importantly the time Caputo derivative. The attained solutions convey relevant characteristics of MRI in biological tissues not replicated by standard diffusion, including super-diffusive and sub-diffusive regimes in signal decay and the diffusion-driven incomplete refocusing of spins at the end of the sequence. These results may therefore have significant implications for advancing the current interpretation of MRI, and for the estimation of tissue properties based on exact solutions to underlying diffusive processes.

  7. A Bloch-based procedure for dispersion analysis of lattices with periodic time-varying properties

    Science.gov (United States)

    Vila, Javier; Pal, Raj Kumar; Ruzzene, Massimo; Trainiti, Giuseppe

    2017-10-01

    We present a procedure for the systematic estimation of the dispersion properties of linear discrete systems with periodic time-varying coefficients. The approach relies on the analysis of a single unit cell, making use of Bloch theorem along with the application of a harmonic balance methodology over an imposed solution ansatz. The solution of the resulting eigenvalue problem is followed by a procedure that selects the eigen-solutions corresponding to the ansatz, which is a plane wave defined by a frequency-wavenumber pair. Examples on spring-mass superlattices demonstrate the effectiveness of the method at predicting the dispersion behavior of linear elastic media. The matrix formulation of the problem suggests the broad applicability of the proposed technique. Furthermore, it is shown how dispersion can inform about the dynamic behavior of time-modulated finite lattices. The technique can be extended to multiple areas of physics, such as acoustic, elastic and electromagnetic systems, where periodic time-varying material properties may be used to obtain non-reciprocal wave propagation.

  8. Abner Doubleday, Marc Bloch, and the cultural significance of baseball in rural America.

    Science.gov (United States)

    Vaught, David

    2011-01-01

    In 1907 baseball's promoters decreed that Civil War hero Abner Doubleday created the game in the village of Cooperstown, New York, in 1839. Baseball thus acquired a distinctly rural American origin and a romantic pastoral appeal. Skeptics have since presented irrefutable evidence that America's pastime was neither born in the United States nor was a product of rural life. But in their zeal to debunk the myth of baseball's rural beginnings, historians have fallen prey to what Annales School founder Marc Bloch famously called the "idol of origins," and all but neglected the very real phenomenon of rural baseball itself. The claim that baseball has always been "a city game for city men" does not stand up to empirical scrutiny anymore than the Doubleday myth itself, as this address demonstrates with three case studies -- Cooperstown in the 1830s, Davisville, California, in the 1880s, and Milroy, Minnesota, in the 1950s. Baseball may have been a source of rural nostalgia for city people, but it was the sport of choice for farmers and a powerful cultural agent.

  9. Photonic lattices in organic microcavities: Bloch states and control of lasing

    Science.gov (United States)

    Mischok, Andreas; Brückner, Robert; Fröb, Hartmut; Lyssenko, Vadim G.; Leo, Karl

    2015-09-01

    Organic microcavities comprising the host:guest emitter system Alq3:DCM offer an interesting playground to experimentally study the dispersion characteristics of laterally patterned microlasers due to the broad emission spectrum and large oscillator strength of the organic dye. By structuring of metallic or dielectric sublayers directly on top of the bottom mirror, we precisely manipulate the mode structure and influence the coherent emission properties of the device. Embedding silver layers into a microcavity leads to an interaction of the optical cavity-state in the organic layer and the neighboring metal which red-shifts the cavity resonance, creating a Tamm-plasmon-polariton state. A patterning of the metal can in turn be exploited to fabricate deep photonic wells of micron-size, efficiently confining light in lateral direction. In periodic arrays of silver wires, we create a Kronig-Penney-like optical potential in the cavity and in turn observe optical Bloch states spanning over several photonic wires. We modify the Kronig-Penney theory to analytically describe the full far-field emission dispersion of our cavities and show the emergence of either zero- , π-, or 2π- phase-locking in the system. By investigating periodic SiO2 patterns, we experimentally observe stimulated emission from the ground and different excited discrete states at room temperature and are able to directly control the laser emission from both extended and confined modes of the photonic wires at room-temperature.

  10. Effects of the projectile electronic structure on Bethe-Bloch stopping parameters for Ag

    Energy Technology Data Exchange (ETDEWEB)

    Moussa, D., E-mail: djamelmoussa@gmail.co [USTHB, Faculte de Physique, B.P. 32, 16111 Bab-Ezzouar, Algiers (Algeria); Damache, S. [Division de Physique, CRNA, 02 Bd. Frantz Fanon, B.P. 399 Alger-gare, Algiers (Algeria); Ouichaoui, S., E-mail: souichaoui@gmail.co [USTHB, Faculte de Physique, B.P. 32, 16111 Bab-Ezzouar, Algiers (Algeria)

    2010-06-15

    Energy losses of protons and alpha particles in silver have been accurately measured under the same experimental conditions over the velocity range E{sub lab}=(0.192-2.595) MeV/amu using the transmission method. Deduced S(E) stopping powers are compared to most accurate ones from the literature, to values generated by the SRIM-2008 computer code and to ICRU-49 compilation. They were analyzed in the framework of modified Bethe-Bloch theory for extracting Ag target mean excitation and ionization potential, I, and Barkas effect parameter, b. Values of (466{+-}5) eV and 1.20{+-}0.01 for these two parameters were inferred from the proton S(E) data while the alpha particle data yielded values of (438{+-}4) eV and 1.38{+-}0.01, respectively. The (I, b) stopping parameters thus exhibit opposite variations as the projectile charge increases, similarly as we have found previously for nickel . This can be ascribed only to an effect of the projectile electronic structure at low velocities. The obtained results are discussed in comparison to previous ones reported in the literature.

  11. DEVELOPMENTS OF DIGESTIVE TRACT IN LARVAE OF CLIMBING PERCH, Anabas testudineus (Bloch

    Directory of Open Access Journals (Sweden)

    Yulintine Yulintine

    2010-12-01

    Full Text Available Climbing perch, Anabas testudineus (Bloch is a potential species for aquaculture in Kalimantan, Indonesia and belongs to Anabantidae family. The development of its digestive tract was evaluated on larvae reared under culture conditions of 28oC-30oC, from hatching to 30 days after hatching using histological and morphological methods. The larvae were kept in six 100-L tanks. They were fed with rotifers and microalgae from day 2nd after hatching to day 10th; Artemia nauplii from day 7th to day 15th; Artemia meta-nauplii from day 15th to day 20th; and Tubifex worm from day 20th onwards. The development of digestive tract in climbing perch followed the general pattern described for other species. Shortly after hatching, its digestive system was found to be consisted of an undifferentiated straight tube laying dorsally to the yolk sac. At first feeding (day 2nd, both mouth and anus had opened and the yolk sac was partially absorbed. On day 3, the digestive tract was fully differentiated into buccopharynx, esophagus, intestine and rectum. The two pyloric caeca appeared on day 25th after hatching, indicating the transition from larval to juvenile stage and acquisition of an adult type of digestion.

  12. The peripheral olfactory organ in the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801

    Directory of Open Access Journals (Sweden)

    Laura Ghigliotti

    2015-11-01

    Full Text Available The Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801 is the largest predatory fish in Arctic waters. The socio-economic significance of Greenland shark is demonstrated by its impact on the fishing cultures in Greenland, Scandinavia and Iceland for centuries. The fundamental biology and ecological role of Greenland shark, on the other hand, is virtually unknown. Although knowledge of its life history is limited, increasing evidence indicates that the Greenland shark may undertake long-distance migrations and perform vertical movements from the surface to the deep sea. It is an omnivorous species feeding on carrion and a wide variety of pelagic and bottom-dwelling organisms ranging from invertebrates to mammals, and including active species such as fishes and seals. Accordingly, Greenland shark should be recognized as a top predator, with a strong potential to influence the trophic dynamics of the Arctic marine ecosystem. The sensory biology of Greenland shark is scarcely studied, and considering the importance of olfaction in chemoreception, feeding and other behavioral traits, we examined the architecture of the peripheral olfactory organ where olfactory cues are received from the environment – the olfactory rosette. The structural organization of the olfactory rosette, in terms of histological features of the sensory epithelium, number of primary lamellae and total sensory surface area, provides a first proxy of the olfactory capability of Greenland shark. Based on own results and published studies, the overall morphology of the olfactory rosette is viewed in context of the functional and trophic ecology among other elasmobranch species.

  13. Emergence of quasiparticle Bloch states in artificial crystals crafted atom-by-atom

    Directory of Open Access Journals (Sweden)

    Jan Girovsky, Jose L. Lado, Floris E. Kalff, Eleonora Fahrenfort, Lucas J. J. M. Peters, Joaquín Fernández-Rossier, Alexander F. Otte

    2017-06-01

    Full Text Available The interaction of electrons with a periodic potential of atoms in crystalline solids gives rise to band structure. The band structure of existing materials can be measured by photoemission spectroscopy and accurately understood in terms of the tight-binding model, however not many experimental approaches exist that allow to tailor artificial crystal lattices using a bottom-up approach. The ability to engineer and study atomically crafted designer materials by scanning tunnelling microscopy and spectroscopy (STM/STS helps to understand the emergence of material properties. Here, we use atom manipulation of individual vacancies in a chlorine monolayer on Cu(100 to construct one- and two-dimensional structures of various densities and sizes. Local STS measurements reveal the emergence of quasiparticle bands, evidenced by standing Bloch waves, with tuneable dispersion. The experimental data are understood in terms of a tight-binding model combined with an additional broadening term that allows an estimation of the coupling to the underlying substrate.

  14. An Update on the Invasion of Weakfish Cynoscion regalis (Bloch & Schneider, 1801 (Actinopterygii: Sciaenidae into Europe

    Directory of Open Access Journals (Sweden)

    Pedro Morais

    2017-10-01

    Full Text Available New information on weakfish introduction vectors, its invasive status, distribution, and use as a fishing resource arose after the publication of “The transatlantic introduction of weakfish Cynoscion regalis (Bloch & Schneider, 1801 (Sciaenidae, Pisces into Europe” by Morais and Teodósio (2016. Currently, the first known report of weakfish in Europe dates back to September 2009, with a specimen captured in the Schelde estuary (Belgium/The Netherlands. This fact suggests that weakfish could have been introduced into Europe via multiple and independent ballast water introduction events, and not through a point-source introduction event with subsequent dispersion as previously hypothesized. It is also unlikely that Schelde weakfish migrated southwards to colonize Iberian aquatic ecosystems. Weakfish have established a population in the Gulf of Cádiz region and have already reached an invasive status in the Sado estuary (Portugal. Weakfish were also captured in several other locations along the Portuguese coast, including the Tagus and Mira estuaries at least since 2013 or 2014, and the Ria Formosa lagoon in 2017. Tagus anglers caught weakfish specimens of ~1 kg and ~40 cm in November 2016, which corresponds to fish of 3+ years of age in the native range. The presence of weakfish in the Tagus estuary is still fairly unknown to local anglers. Sado weakfish has already been sold in local fish markets in southern Portugal for 3 to 10 € kg−1. However, we consider that the weakfish sale price is underrated in comparison with other wild species (e.g., meagre, seabass, gilthead seabream. Increasing sale price will convince fishers to use weakfish as a new fishing resource; however, it is necessary to promote the species among consumers and evaluate consumers’ preference in respect to other species. A putative biological threat might turn into a new valuable fishing resource by implementing adequate management solutions.

  15. Nutritional evaluation of the moonfish Mene maculata (Bloch & Schneider, 1801 from Parangipettai, southeast coast of India

    Directory of Open Access Journals (Sweden)

    Palanivel Bharadhirajan

    2014-01-01

    Full Text Available Objective: To assess the nutritions in Mene maculata (Bloch & Schneider, 1801 (M. maculata. Methods: Fishes (14-16 cm were obtained from the landings at Parangipettai for the evaluation of biochemical composition. The present study deals with biochemical composition such as protein, carbohydrate, lipid, amino acids fatty acids, vitamins and minerals which were evaluated in the moonfish. Results: The results of proximate composition in M. maculata showed that the percentage of protein was high in the tissue (23.16%, followed by the carbohydrate (1.3% and lipid (2.62%. Totally 20 essential and nonessential amino acids were present at the rate of 46.72% and 43.91%. In the analysis, the fatty acid profile by gas chromatography revealed the presence of higher amount of saturated fatty acid (palmitic acid 22.17% than monounsaturated fatty acid (oleic acid 14.51% and polyunsaturated fatty acid (alpha linolenic acid 16.07%. Vitamins were detected in M. maculata. Among them, vitamin A was found in higher levels (124.5 mg/g, whereas vitamin B6 was noticed as lower levels (0.34 mg/g. In the present study, totally 5 macro minerals and 2 trace minerals were reported. The macro mineral calcium (156.7 mg/g was found at the highest level and other minerals such as sodium (31.98 mg/g, potassium (21.33 mg/g, copper (1.43 mg/g and magnesium (0.341 mg/g were also detected in the moonfish. Conclusions: The result showed that the moonfish M. maculata tissue is a valuable food recipe for human consumption, due to its high quality protein and well-balanced amino acids.

  16. Several Growth Characteristics of an Invasive Cyprinid Fish (Carassius gibelio Bloch, 1782

    Directory of Open Access Journals (Sweden)

    Sait BULUT

    2013-05-01

    Full Text Available Age composition, length-weight relationships, growth, and condition factors of the gibel carp (Carassius gibelio Bloch, 1782 were determined using specimens collected from Seyitler Reservoir between July 2005 to June 2006. A total of 149 gibel carp were observed and examined. The age composition of the samples ranged between I and VII years of age. It has been determined than 82.55% of the obtained samples are comprised of females, 16.11% is comprised of males and 1.34% is comprised of immature. The population is dominated by females able to reproduce gynogenetically. The mean fork lengths and mean weights of the population were 14.8-32.5 cm and 43.1-807.3 g respectively. The length-weight relation were calculated as W = 0.0696 L2.132, r=0.838 for females, for males W = 0.2942 L2.6417 r=0.784 and W = 0.0274 L2.9382, r=0.813 for all samples. The mean Fulton Condition Factor was calculated as 2.342 for females, 2.064 for males and 2.276 for all samples. Age-length and age-weight relations were determined according to von Bertalanffy growth equation formula. Growth parameters of the population were Lt = 48.09 [1-e-0.093(t+0.29], and Wt=2323.62 [1-e-0.093(t+0.29]2.9382. The growth performance index value (Ø´ was computed as 5.37 for all specimens.

  17. Stability and convergence of an implicit numerical method for the space and time fractional Bloch-Torrey equation.

    Science.gov (United States)

    Yu, Qiang; Liu, Fawang; Turner, Ian; Burrage, Kevin

    2013-05-13

    Fractional-order dynamics in physics, particularly when applied to diffusion, leads to an extension of the concept of Brownian motion through a generalization of the Gaussian probability function to what is termed anomalous diffusion. As magnetic resonance imaging is applied with increasing temporal and spatial resolution, the spin dynamics is being examined more closely; such examinations extend our knowledge of biological materials through a detailed analysis of relaxation time distribution and water diffusion heterogeneity. Here, the dynamic models become more complex as they attempt to correlate new data with a multiplicity of tissue compartments, where processes are often anisotropic. Anomalous diffusion in the human brain using fractional-order calculus has been investigated. Recently, a new diffusion model was proposed by solving the Bloch-Torrey equation using fractional-order calculus with respect to time and space. However, effective numerical methods and supporting error analyses for the fractional Bloch-Torrey equation are still limited. In this paper, the space and time fractional Bloch-Torrey equation (ST-FBTE) in both fractional Laplacian and Riesz derivative form is considered. The time and space derivatives in the ST-FBTE are replaced by the Caputo and the sequential Riesz fractional derivatives, respectively. Firstly, we derive an analytical solution for the ST-FBTE in fractional Laplacian form with initial and boundary conditions on a finite domain. Secondly, we propose an implicit numerical method (INM) for the ST-FBTE based on the Riesz form, and the stability and convergence of the INM are investigated. We prove that the INM for the ST-FBTE is unconditionally stable and convergent. Finally, we present some numerical results that support our theoretical analysis.

  18. Antes, desde y para el exilio. Herencia de esta época (1935/1962 de Ernst Bloch

    Directory of Open Access Journals (Sweden)

    Salmerón Infante, Miguel

    2009-10-01

    Full Text Available The first edition of Erbschaft dieser Zeit was published in Zurich in 1935, during Ernst Bloch’s five-year period of emigration from Nazi-Germany in various European capitals before his final emigration to America for ten years in 1938. In this book Bloch made a courageous stand in defence of the artistic avant-garde against the dogmatic advocates of socialist realism. His particularly adversary was Georg Lukács. But of course one of the most fascinating aspects of the book is that is also reads as a contemporary observation of the rise of the Nazis. Erbschaft is undoubtedly the major work of Weimar Germany Exile.La primera edición de Erbschaft dieser Zeit fue publicada en 1935 en Zurich, durante la emigración de Ernst Bloch de la Alemania nazi por un período de cinco años en el que residió en varias capitales europeas antes de su marcha definitiva a América en 1938, donde vivió diez años. En este libro Bloch hace una encorajinada defensa de la vanguardia artística contra los abogados del realismo socialista. Su adversario específico era Georg Lukács. Pero sin duda alguna uno de los aspectos más fascinantes de este libro es que puede leerse como una observación contemporánea de la ascensión al poder de los nazis. Erbschaft es indudablemente la obra clave del exilio de la Alemania de Weimar.

  19. Web-based description of the space radiation environment using the Bethe-Bloch model

    Science.gov (United States)

    Cazzola, Emanuele; Calders, Stijn; Lapenta, Giovanni

    2016-01-01

    Space weather is a rapidly growing area of research not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary, bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We give a new approach to presenting the topic by developing a web-based application that combines some of the fundamental concepts from these two fields into a single tool that can be used in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to rapidly assess the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions (ACE, GOES-13, GOES-15) to produce a first order approximation of the radiation dose an astronaut would receive during a mission of exploration in deep space (i.e. far from the Earth’s shielding magnetic field and from the radiation belts). DREADCode is based on an easy-to-use GUI interface available online from the European Space Weather Portal (www.spaceweather.eu/dreadcode). The core of the radiation transport computation to produce the radiation dose from the observed fluence of radiation observed by the spacecraft fleet considered is based on a relatively simple approximation: the Bethe-Bloch equation. DREADCode also assumes a simplified geometry and material configuration for the shields used to compute the dose. The approach is approximate and sacrifices some important physics on the altar of rapid execution time, which allows a real-time operation scenario. There is no intention here to produce an operational tool for use in space science and engineering. Rather, we present an educational tool at undergraduate level that uses modern web-based and programming methods to learn some of the most important

  20. KONSERVASI GENETIK IKAN BETOK (Anabas testudineus Bloch 1792 DI PERAIRAN RAWA, KALIMANTAN SELATAN

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    Slamat Slamat

    2016-05-01

    Full Text Available Penelitian ini dilakukan dengan menggunakan sample ikan betok (Anabas testudineus Bloch 1972 yang berasal dari perairan rawa Kalimantan Selatan, dengan tujuan untuk mendeskripsikan keragaman  genetik dan aspek konservasinya dengan metode amplifikasi mtDNA. Proses amplifikasi mtDNA ikan betok terjadi di daerah D Loop.  Hasil analisis mt-DNA D Loop ikan betok menunjukkan bahwa, analisis keseimbangan populasi Hardy-Weinberg  berkisar antara 0,02 - 0,09, sedangkan haplotipe tertinggi terdapat pada rawa monoton (0,9384, kemudian tadah hujan (0,7111 dan pasang surut (0,6.  Heterozigositas ditemukan unik pada populasi rawa monoton (BAAAA dan rawa pasang surut (BAACA dan umum di temukan di ketiga ekosistem rawa (AAABA.  Ikan betok di bagi menjadi dua stok populasi yaitu populasi rawa monoton dan pasang surut serta stok tadah hujan.  Konsep utama dalam konservasi genetik adalah fitness population dimana populasi dipertahankan minimal 500 ekor/kawasan. Untuk meningkatkan keragaman genetik ikan betok, dilakukan dengan cara introduksi individu-individu baru yang memiliki keragaman genetik yang lebih tinggi kedalam populasi lokal, restocking dan membuat kawasan suaka yang dilindungi oleh Dinas Perikanan setempat bersama-sama dengan masyarakat di sekitar perairan rawa tersebut.   The research was conducted using climbing perch samples originated from the swampy waters of the southern Borneo, and the objektive of this study to investigate the genetic diversity and the conservation aspect using mtDNA amplification method.  mtDNA amplification process occurs in the D Loop region.  The results of the analysis of D-Loop mtDNA of climbing perch showed that, the analysis of Hardy-Weinberg equilibrium population ranged from 0.02 to 0.09, while the highest haplotypes found in swamp bogs (monotonic (0.9384 then rainfed (0.7111 and tides (0.6. Heterozygosity was found uniquely in the swamp monotonic population (BAAAA and marsh tides (BAACA and common in all

  1. Plasmonic Photonic-Crystal Slabs: Visualization of the Bloch Surface Wave Resonance for an Ultrasensitive, Robust and Reusable Optical Biosensor

    Directory of Open Access Journals (Sweden)

    Alexander V. Baryshev

    2014-12-01

    Full Text Available A one-dimensional photonic crystal (PhC with termination by a metal film—a plasmonic photonic-crystal slab—has been theoretically analyzed for its optical response at a variation of the dielectric permittivity of an analyte and at a condition simulating the molecular binding event. Visualization of the Bloch surface wave resonance (SWR was done with the aid of plasmon absorption in a dielectric/metal/dielectric sandwich terminating a PhC. An SWR peak in spectra of such a plasmonic photonic crystal (PPhC slab comprising a noble or base metal layer was shown to be sensitive to a negligible variation of refractive index of a medium adjoining to the slab. As a consequence, the considered PPhC-based optical sensors exhibited an enhanced sensitivity and a good robustness in comparison with the conventional surface-plasmon and Bloch surface wave sensors. The PPhC biosensors can be of practical importance because the metal layer is protected by a capping dielectric layer from contact with analytes and, consequently, from deterioration.

  2. Full-angle Negative Reflection with An Ultrathin Acoustic Gradient Metasurface: Floquet-Bloch Modes Perspective and Experimental Verification

    KAUST Repository

    Liu, Bingyi

    2017-07-01

    Metasurface with gradient phase response offers new alternative for steering the propagation of waves. Conventional Snell\\'s law has been revised by taking the contribution of local phase gradient into account. However, the requirement of momentum matching along the metasurface sets its nontrivial beam manipulation functionality within a limited-angle incidence. In this work, we theoretically and experimentally demonstrate that the acoustic gradient metasurface supports the negative reflection for full-angle incidence. The mode expansion theory is developed to help understand how the gradient metasurface tailors the incident beams, and the full-angle negative reflection occurs when the first negative order Floquet-Bloch mode dominates. The coiling-up space structures are utilized to build desired acoustic gradient metasurface and the full-angle negative reflections have been perfectly verified by experimental measurements. Our work offers the Floquet-Bloch modes perspective for qualitatively understanding the reflection behaviors of the acoustic gradient metasurface and enables a new degree of the acoustic wave manipulating.

  3. Mathematical Development and Computational Analysis of Harmonic Phase-Magnetic Resonance Imaging (HARP-MRI) Based on Bloch Nuclear Magnetic Resonance (NMR) Diffusion Model for Myocardial Motion.

    Science.gov (United States)

    Dada, Michael O; Jayeoba, Babatunde; Awojoyogbe, Bamidele O; Uno, Uno E; Awe, Oluseyi E

    2017-09-13

    Harmonic Phase-Magnetic Resonance Imaging (HARP-MRI) is a tagged image analysis method that can measure myocardial motion and strain in near real-time and is considered a potential candidate to make magnetic resonance tagging clinically viable. However, analytical expressions of radially tagged transverse magnetization in polar coordinates (which is required to appropriately describe the shape of the heart) have not been explored because the physics required to directly connect myocardial deformation of tagged Nuclear Magnetic Resonance (NMR) transverse magnetization in polar geometry and the appropriate harmonic phase parameters are not yet available. The analytical solution of Bloch NMR diffusion equation in spherical geometry with appropriate spherical wave tagging function is important for proper analysis and monitoring of heart systolic and diastolic deformation with relevant boundary conditions. In this study, we applied Harmonic Phase MRI method to compute the difference between tagged and untagged NMR transverse magnetization based on the Bloch NMR diffusion equation and obtained radial wave tagging function for analysis of myocardial motion. The analytical solution of the Bloch NMR equations and the computational simulation of myocardial motion as developed in this study are intended to significantly improve healthcare for accurate diagnosis, prognosis and treatment of cardiovascular related deceases at the lowest cost because MRI scan is still one of the most expensive anywhere. The analysis is fundamental and significant because all Magnetic Resonance Imaging techniques are based on the Bloch NMR flow equations.

  4. A redescription of the South American Catfish Loricariichthys maculatus (Bloch, 1794), with designation of the lectotype and restriction of its type locality (Pisces, Siluriformes, Loricariidae)

    NARCIS (Netherlands)

    Isbrücker, I.J.H.

    1971-01-01

    The type species of the genus Loricariichthys Bleeker, 1862, Loricariichthys maculatus (Bloch, 1794), is redescribed from two syntypes, one of which is designated the lectotype. The same specimen is also designated the neotype for Plecostomus cataphracta Gronovius (ed. Gray), 1854 (non Loricaria

  5. Pisces, Perciformes, Eleotridae, Dormitator maculatus (Bloch, 1792: Distribution extension for Patos-Mirim lagoon system, state of Rio Grande do Sul, Brazil.

    Directory of Open Access Journals (Sweden)

    Volcan, M. V.

    2010-01-01

    Full Text Available We present here the record of Dormitator maculatus (Bloch, 1792 to the Patos-Mirim lagoon system, RioGrande do Sul, Brazil. This is also the southernmost occurrence in South America, extending species range ca. 150 km fromthe previously known localities.

  6. A força da tradição: a persistência do antigo regime historiográfico na obra de Marc Bloch The power of tradition: the persistence of historic old regime in Marc Bloch's Oeuvre

    Directory of Open Access Journals (Sweden)

    Tiago de Melo Gomes

    2006-12-01

    Full Text Available Este artigo se foca na obra de Marc Bloch, em especial em seu livro tido como mais importante, A Sociedade Feudal (1939, argumentando que mesmo no trabalho de um dos mais importantes do século XX ainda é possível encontrar elementos associados a uma historiografia mais tradicional.This article is focused on Marc Bloch's oeuvre, especially in his so-called masterpiece, Feudal Society (1939, arguing that even in the work of one of the most important historians of the century, we can find important elements of the traditional historiography.

  7. El anacronismo en la historia: ¿error o posibilidad? A propósito de las reflexiones sobre el tiempo en Carlo Ginzburg, Marc Bloch y Georges Didi-Huberman

    National Research Council Canada - National Science Library

    María Eugenia Chaves Maldonado

    2016-01-01

      In his unfinished and posthumously published book Apologie pour l'histoire, Marc Bloch bestowed on future historians a seminal legacy of critical reflections on the concept of time as the object of historical analysis...

  8. Caracterização da piscicultura na região do Vale do Ribeira - SP Characterization of fish farming in the Ribeira Valley region - SP

    Directory of Open Access Journals (Sweden)

    Daniela Castellani

    2005-02-01

    Full Text Available Este trabalho buscou caracterizar a piscicultura na Região do Vale do Ribeira quanto aos sistemas de manejo. Estudaram-se quarenta e duas pisciculturas sendo que, destas, 36 praticam o sistema semi-intensivo e seis o sistema intensivo, com os seguintes objetivos: engorda de peixes, produção de alevinos e pesque-pagues. Foram listadas 41 espécies de peixes cultivadas. Apenas 6 espécies são nativas da Bacia do Rio Ribeira de Iguape: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier e Valenciennes, 1928, jundiá (Rhamdia quelen Quoy e Gaimard, 1824, cascudo (Hypostomus sp Marschall, 1873 e cará (Geophagus brasiliensis Quoy e Gaimard, 1824. Em 95% das pisciculturas foram verificadas fugas de peixes exóticos e alóctones dos cultivos. A tilápia nilótica (Oreochromis niloticus Linneaus, 1758 foi a espécie mais freqüente em escapes, e também é a segunda mais cultivada pelos piscicultores, perdendo somente para o pacu (Piaractus mesopotamicus Halmberg, 1887. Foi possível verificar mediante o cálculo da conversão alimentar, que há um desperdício anual de cerca de 32% da ração utilizada nos cultivos pesquisados. A piscicultura encontra-se em plena expansão nesta região, e já representa a atividade agropecuária mais importante após a bananicultura.The aim of this work was to characterize the fish farming in the Ribeira de Iguape Basin, southern São Paulo State (Brazil, in relation to the management systems. Forty two farms were studied. A semi-intensive system is used by 36 farmers, while an intensive system is used only by 6 studied farmers. Their objectives were raising fish, juvenile fish production and sportive fishery. Forty one fish species were found to be cultivated, but only six were native species from Ribeira Valley: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier and Valenciennes, 1928, jundi

  9. A Bloch equation approach to intensity dependent optical spectra of light harvesting complex II: excitation dependence of light harvesting complex II pump-probe spectra.

    Science.gov (United States)

    Richter, Marten; Renger, Thomas; Knorr, Andreas

    2008-01-01

    On the basis of the recent progress in the resolution of the structure of the antenna light harvesting complex II (LHC II) of the photosystem II, we propose a microscopically motivated theory to predict excitation intensity-dependent spectra. We show that optical Bloch equations provide the means to include all 2( N ) excited states of an oligomer complex of N coupled two-level systems and analyze the effects of Pauli Blocking and exciton-exciton annihilation on pump-probe spectra. We use LHC Bloch equations for 14 Coulomb coupled two-level systems, which describe the S (0) and S (1) level of every chlorophyll molecule. All parameter introduced into the Hamiltonian are based on microscopic structure and a quantum chemical model. The derived Bloch equations describe not only linear absorption but also the intensity dependence of optical spectra in a regime where the interplay of Pauli Blocking effects as well as exciton-exciton annihilation effects are important. As an example, pump-probe spectra are discussed. The observed saturation of the spectra for high intensities can be viewed as a relaxation channel blockade on short time scales due to Pauli blocking. The theoretical investigation is useful for the interpretation of the experimental data, if the experimental conditions exceed the low intensity pump limit and effects like strong Pauli Blocking and exciton-exciton annihilation need to be considered. These effects become important when multiple excitations are generated by the pump pulse in the complex.

  10. STUDIES REGARDING THE INFLUENCE OF TOPSIN M 70 PU FUNGICIDE ON CARASSIUS AURATUS GIBELIO BLOCH L. 1758

    Directory of Open Access Journals (Sweden)

    Bogdan Mihai Udroiu

    2015-12-01

    Full Text Available The main objective of this study is to see how the metylthiophanate fungicide influences the energetic metabolism and the breathing rhythm at Carassius auratus gibelio Bloch L. 1758. Experimental samples were subjected to under-lethal concentrations of 3.75mg/l, 7.5mg/l, 15mg/l and 30mg/l methyl-thiophanate fungicide from 24 to 336 hours. The physiologic parameter with the highest growth rate was the oxygen consumption, which, at the concentration of 7.5mg/l grew by 40.3% in 6 hours, compared to the witness values, registering the value of 179.52 mg oxygen/l/h compared to 127.95 mg oxygen/l/h. Also, the breathing rhythm grew at the concentration of 7.5 mg/l by 24.76% in 6 hours, compared to the witness values. At the concentration of 30mg/l, both physiologic parameters decreased. So, after 6 hours, the oxygen consumption decrease up to 31.38% from the witness values, registering the value of 51.503mg oxygen/l/h compared to 164.09mg oxygen/l/h, and the breathing rhythm decreased to 84.3% compared to the witness martor.

  11. Magnetic susceptibility of Dirac fermions, Bi-Sb alloys, interacting Bloch fermions, dilute nonmagnetic alloys, and Kondo alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buot, Felix A., E-mail: fbuot@gmu.edu [Computational Materials Science Center, George Mason University, Fairfax, VA 22030 (United States); TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines); C& LB Research Institute, Carmen, Cebu 6005 (Philippines); Otadoy, Roland E.S.; Rivero, Karla B. [TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines)

    2017-03-01

    Wide ranging interest in Dirac Hamiltonian is due to the emergence of novel materials, namely, graphene, topological insulators and superconductors, the newly-discovered Weyl semimetals, and still actively-sought after Majorana fermions in real materials. We give a brief review of the relativistic Dirac quantum mechanics and its impact in the developments of modern physics. The quantum band dynamics of Dirac Hamiltonian is crucial in resolving the giant diamagnetism of bismuth and Bi-Sb alloys. Quantitative agreement of the theory with the experiments on Bi-Sb alloys has been achieved, and physically meaningful contributions to the diamagnetism has been identified. We also treat relativistic Dirac fermion as an interband dynamics in uniform magnetic fields. For the interacting Bloch electrons, the role of translation symmetry for calculating the magnetic susceptibility avoids any approximation to second order in the field. The expressions for magnetic susceptibility of dilute nonmagnetic alloys give a firm theoretical foundation of the empirical formulas used in fitting experimental results. The unified treatment of all the above calculations is based on the lattice Weyl-Wigner formulation of discrete phase-space quantum mechanics. For completeness, the magnetic susceptibility of Kondo alloys is also given since Dirac fermions in conduction band and magnetic impurities exhibit Kondo effect.

  12. HÁBITOS ALIMENTARIOS DE LA MAYUPA (Sternopygus macrurus Bloch & Schneider, 1801 EN EL RÍO SINÚ, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Javier Barrera-Chica

    2009-12-01

    Full Text Available Objetivo. Estudiar los hábitos alimentarios de la Mayupa (Sternopygus macrurus Bloch & Schneider, 1801 en el río Sinú, Colombia. Materiales y métodos. El contenido estomacal se evaluó con el coeficiente de vacuidad, grado de llenado, grado de digestión, frecuencia de ocurrencia, frecuencia numérica, gravimetría, indice de importancia relativa (IIR y la relación longitud intestinal (LI-longitud total (LT. Resultados. Solo pocos estómagos se encontraron vacíos (CV =6.9% y el 60.0% de las presas se encontraron frescas. Se identificaron cuatro ítems alimentarios: peces, crustáceos, material vegetal y otros. Peces fue el ítem más frecuente (76.9%, abundante (48.3%, con mayor composición por peso (81.9% y con mayor importancia relativa (63.2%. Conclusiones. Los resultados obtenidos permiten inferir que la Mayupa es un pez de hábitos alimentarios carnívoros, con preferencia por los peces.

  13. Pemaparan merkuri nitrat (Hg (No32 dengan konsentrasi berbeda pada jaringan hati benih ikan kakap putih (Lates calcarifer Bloch: tinjauan histologi

    Directory of Open Access Journals (Sweden)

    Munawar Khalil

    2013-12-01

    Full Text Available Tujuan penelitian ini adalah untuk mempelajari pengaruh logam berat merkuri nitrat (Hg(NO32 pada struktur histologis hati benih ikan kakap putih (Lates calcarifer Bloch yang dipelihara di air laut. Analisis struktur jaringan hati dilakukan melalui teknik histologi. Hasil penelitian menunjukkan bahwa Hg(NO32 memberikan efek negatif pada hati benih ikan. Pada jaringan hati, (Hg(NO32 menyebabkan kerusakan atrophy, necrosis, lapisan antar sel hati berpisah, perlemakan hati, pembengkakan sel yang tidak beraturan, degenerasi pada vacuola, terbentuknya ruang antar sel, hepatitis, sirrhosis dan terdapatnya akumulasi logam berat Hg(NO32 dalam jaringan hati.

  14. Electron-spin relaxation in bulk III-V semiconductors from a fully microscopic kinetic spin Bloch equation approach

    Science.gov (United States)

    Jiang, J. H.; Wu, M. W.

    2009-03-01

    Electron spin relaxation in bulk III-V semiconductors is investigated from a fully microscopic kinetic spin Bloch equation approach where all relevant scatterings, such as, the electron-nonmagnetic-impurity, electron-phonon, electron-electron, electron-hole, and electron-hole exchange (the Bir-Aronov-Pikus mechanism) scatterings are explicitly included. The Elliott-Yafet mechanism is also fully incorporated. This approach offers a way toward thorough understanding of electron spin relaxation both near and far away from the equilibrium in the metallic regime. The dependences of the spin relaxation time on electron density, temperature, initial spin polarization, photo-excitation density, and hole density are studied thoroughly with the underlying physics analyzed. We find that these dependences are usually qualitatively different in the nondegenerate and degenerate regimes. In contrast to the previous investigations in the literature, we find that: (i) In n -type materials, the Elliott-Yafet mechanism is less important than the D’yakonov-Perel’ mechanism, even for the narrow band-gap semiconductors such as InSb and InAs. (ii) The density dependence of the spin relaxation time is nonmonotonic and we predict a peak in the metallic regime in both n -type and intrinsic materials. (iii) In intrinsic materials, the Bir-Aronov-Pikus mechanism is found to be negligible compared with the D’yakonov-Perel’ mechanism. We also predict a peak in the temperature dependence of spin relaxation time which is due to the nonmonotonic temperature dependence of the electron-electron Coulomb scattering in intrinsic materials with small initial spin polarization. (iv) In p -type III-V semiconductors, the Bir-Aronov-Pikus mechanism dominates spin relaxation in the low-temperature regime only when the photoexcitation density is low. When the photoexcitation density is high, the Bir-Aronov-Pikus mechanism can be comparable with the D’yakonov-Perel’ mechanism only in the moderate

  15. Hybrid Bloch brane

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Lima, Elisama E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

    2017-02-15

    This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios. (orig.)

  16. BIOLOGICAL CHARACTERISTICS OF PRUSSIAN CARP (CARASSIUS AURATUS GIBELIO (BLOCH, 1782 COMMERCIAL STOCK OF THE DNIEPER-BUG ESTUARY

    Directory of Open Access Journals (Sweden)

    К. Heina

    2017-09-01

    Full Text Available Purpose. To provide the biological assessment of the silver Prussian carp (Carassius auratus gibelio (Bloch, 1782 commercial stock of the Dnieper-Bug estuary in the conditions of the transformed Dnieper river flow. Methodology. During the analysis of the biological state of the Prussian carp commercial stock, the main attention was given to the dynamics of age and sexual structure, length-weight growth rate, absolute fecundity and condition factor. The basic data were collected during the work of control-observation stations of the Institute of Fisheries in the Dnieper-Bug estuary during the current century. The collection and processing of ichthyological materials were performed in accordance with the generally accepted methodologies. Findings. The analysis showed that during the current century, the age structure of the Prussian carp of the Dnieper-Bug estuary was the most labile among other commercial cyprinids. It was found that as a result of an increase in the right wing of the age series, there was a gradual increase of the mean weighted age of its commercial stock. At the beginning of studies (2001-2002, the core of the stock was formed by age-3-6 fish (up ; however in subsequent years, a displacement of dominant groups toward the dominance of age-4-7 fish (more than 80% of the total stock was observed. At the same time, the relative number of age-3 fish (recruits was at a relatively high level – up to 10.6%. The linear growth varied more intensively until the age-5, but it reduced with ageing and did not show high variability. The body weight most variable was in age-4 fish (Cv=9.62%. The noted insignificant deviations in the body weight growth rate of the right wing of the age series was due to stable predominance of females in the stock structure, which were characterized by a variability of the mean weight as a result of different development of gonads. The dynamics of the age-related changes in the condition factor indicated on a

  17. La conciencia de la libertad (La filosofía moral como filosofía de la historia en Ernst Bloch

    Directory of Open Access Journals (Sweden)

    Gimbernat, José Antonio

    1991-10-01

    Full Text Available Not available.

    A partir del concepto hegeliano de «progreso en la conciencia de la libertad », se puede hacer una lectura de la filosofía moral de Bloch como filosofía de la historia. Ello conduce a una reino reinterpretación libre y materialista de Hegel y a una recuperación de la moral en el marxismo. En diálogo con Kant se hace posible descubrir el potencial utópico del énfasis subjetivo de la moral. El objetivo del reino de la libertad marxiano es la clave de una historización política de la libertad, heredada en parte de la tradición liberal, lo que exige a su vez una nueva definición del concepto de progreso.

  18. Anachronism in the writing of History: ¿Error or Possibility? Some reflections about the concept of time in Carlo Ginzburg, Marc Bloch and Georges Didi-Huberman

    Directory of Open Access Journals (Sweden)

    Maria Eugenia Chaves Maldonado

    2016-01-01

    Full Text Available In his unfinished and posthumously published book Apologie pour l’histoire, Marc Bloch bestowed on future historians a seminal legacy of critical reflections on the concept of time as the object of historical analysis. During the last decades, the concept of time in History has experienced a renewed interest by professional historians, in particular in reference to the category of anachronism. The Italian historian Carlo Ginzburg and the French art historian Georges Didi-Huberman are among those engaged in this debate. This article offers a reading of two works by these historians with the purpose of underlying the fundamental influence that Marc Bloch’s ideas on time had in Ginzburg and Didi-Hubermans’ critical interventions.

  19. 3-D micromagnetic simulation of a Bloch line between C-sections of a 180 deg. domain wall in a left brace 1 0 0 right brace iron film

    CERN Document Server

    Huo, S; Tucker, J W; Rainforth, W M; Davies, H A

    2000-01-01

    The micromagnetic structure and energy of a Bloch line (BL) in an asymmetric 180 deg. Bloch domain wall in a 60 nm left brace 1 0 0 right brace iron film have been calculated. In the wall cross-sections on either side of the BL, the flux of magnetisation transverse to that of the domains was 'C' shaped, roughly normal to the plane of the film in its interior but bending nearly parallel to the surfaces as they are approached. The sense of this transverse flux is reversed at the BL. The energy of this BL was calculated to be considerably lower than the energies reported earlier for BLs in walls having 'S' shaped transverse flux cross-sections.

  20. RÉGIMEN ALIMENTARIO DE SIETE ESPECIES ÍCTICAS EN EL EMBALSE DE LA HIDROELÉCTRICA URRÁ (CÓRDOBA, COLOMBIA

    OpenAIRE

    V.J. Atencio-García; E. Kerguelén-Durango; E. Cura Dorado; R. Rosado Carcamo; A. Vallejo; M. Valderrama

    2005-01-01

    El objeto del estudio fue evaluar el régimen alimentario de siete especies de peces que se han establecidoen el embalse de la Hidroeléctrica Urrá (HU). Se analizaron 453 estómagos, distribuidos así: 115 deperico (Tracheolypterus badeli cf), 111 de cacucho (Panaque gibbosus), 108 de yalúa (Cyphocharaxmagdalenae), 89 de mojarra amarilla (Caquetaia kraussii) , 11 de moncholo (Hoplias malabaricus), 10 debarbul ( Pimelodus clarias) y 9 de doncella ( Ageneoisus pardales) . Los contenidos estomacale...

  1. Régimen alimentario de siete especies ícticas en el embalse de la hidroeléctrica Urrá (Córdoba, Colombia)

    OpenAIRE

    Atencio-García, V.J.; Kerguelén-Durango, E.; Cura Dorado, E.; Rosado Carcamo, R.; Vallejo, A.; Valderrama, M.

    2005-01-01

    El objeto del estudio fue evaluar el régimen alimentario de siete especies de peces que se han establecido en el embalse de la Hidroeléctrica Urrá (HU). Se analizaron 453 estómagos, distribuidos así: 115 de perico (Tracheolypterus badeli cf), 111 de cacucho (Panaque gibbosus), 108 de yalúa (Cyphocharax magdalenae), 89 de mojarra amarilla (Caquetaia kraussii) , 11 de moncholo (Hoplias malabaricus), 10 de barbul ( Pimelodus clarias) y 9 de doncella ( Ageneoisus pardales) . Los contenidos estoma...

  2. The fish fauna in tropical rivers: The case of the Sorocaba river basin, SP, Brazil

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    Welber Senteio Smith

    2003-09-01

    Full Text Available A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tietê River, located in the State of São Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twenty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In relation to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representative species in relation to average weight. Largest standard length were recorded for Sternopygus macrurus, Steindachnerina insculpta, Eigenmannia aff. virescens and Cyprinus carpioSe realizó un análisis de las especies de peces de la cuenca del Río Sorocaba, el principal tributario de la margen izquierda del Río Tietê, localizado en el estado de Sao Paulo, Brasil. Las especies fueron recolectadas con redes agalleras. Luego de la identificación de los especímenes, fue determinada su abundancia relativa, peso, y longitud estandar. Hasta el presente, no hay ningún otro estudio que analice estos aspectos en dicha cuenca hidrográfica. Fueron recolectados 55 especies, distribuidas en 18 familias y 6 ordenes. Los Characiformes estuvieron representados por 28 especies, Siluriformes por 17 especies, Gymnotiformes por 3 especies, Perciformes y Cyprinodontiformes por 2 especies, y

  3. Characterization of anomalous relaxation using the time-fractional Bloch equation and multiple echo T2*-weighted magnetic resonance imaging at 7 T.

    Science.gov (United States)

    Qin, Shanlin; Liu, Fawang; Turner, Ian W; Yu, Qiang; Yang, Qianqian; Vegh, Viktor

    2017-04-01

    To study the utility of fractional calculus in modeling gradient-recalled echo MRI signal decay in the normal human brain. We solved analytically the extended time-fractional Bloch equations resulting in five model parameters, namely, the amplitude, relaxation rate, order of the time-fractional derivative, frequency shift, and constant offset. Voxel-level temporal fitting of the MRI signal was performed using the classical monoexponential model, a previously developed anomalous relaxation model, and using our extended time-fractional relaxation model. Nine brain regions segmented from multiple echo gradient-recalled echo 7 Tesla MRI data acquired from five participants were then used to investigate the characteristics of the extended time-fractional model parameters. We found that the extended time-fractional model is able to fit the experimental data with smaller mean squared error than the classical monoexponential relaxation model and the anomalous relaxation model, which do not account for frequency shift. We were able to fit multiple echo time MRI data with high accuracy using the developed model. Parameters of the model likely capture information on microstructural and susceptibility-induced changes in the human brain. Magn Reson Med 77:1485-1494, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  4. A study in the computation time required for the inclusion of strain field effects in Bloch-wave simulations of TEM diffraction contrast images

    Energy Technology Data Exchange (ETDEWEB)

    Dulong, B.J. [Department of Physics, Acadia University, Wolfville, N.S., B4P 2R6 (Canada); Haynes, R.D. [Department of Mathematics and Statistics, Acadia University, Wolfville, N.S., B4P 2R6 (Canada); Robertson, M.D. [Department of Physics, Acadia University, Wolfville, N.S., B4P 2R6 (Canada)], E-mail: michael.robertson@acadiau.ca

    2008-04-15

    As transmission electron microscopy (TEM) imaging techniques continue to become more quantitative, interpretation of the experimental images demands that accurate image simulations be computed incorporating all important aspects of the image including: compositional, crystallographic and microscope effects, as well as contrast due to strain fields arising from stresses created by lattice misfit or defects. Incorporation of the effects of strain fields in the simulation of diffraction-contrast TEM images in the Bloch-wave formalism requires the integration of a system of first-order differential equations in order to modify the excitation amplitudes and produce contrast in the image. This integration is computationally demanding with the time for integration scaling as the cube of the number of beams included in the calculation. In order to investigate the computational requirements of the integration, a variety of numerical integration packages were evaluated with respect to timing and accuracy in the simulation of quantum dot, spherical inclusion and screw dislocation images. It was determined that a class of Adams-multistep methods can provide a decrease in computation time ranging from 2 to 4 as compared to the standard Runge-Kutta 4(5) approach depending on the simulation conditions.

  5. A study in the computation time required for the inclusion of strain field effects in Bloch-wave simulations of TEM diffraction contrast images.

    Science.gov (United States)

    Dulong, B J; Haynes, R D; Robertson, M D

    2008-04-01

    As transmission electron microscopy (TEM) imaging techniques continue to become more quantitative, interpretation of the experimental images demands that accurate image simulations be computed incorporating all important aspects of the image including: compositional, crystallographic and microscope effects, as well as contrast due to strain fields arising from stresses created by lattice misfit or defects. Incorporation of the effects of strain fields in the simulation of diffraction-contrast TEM images in the Bloch-wave formalism requires the integration of a system of first-order differential equations in order to modify the excitation amplitudes and produce contrast in the image. This integration is computationally demanding with the time for integration scaling as the cube of the number of beams included in the calculation. In order to investigate the computational requirements of the integration, a variety of numerical integration packages were evaluated with respect to timing and accuracy in the simulation of quantum dot, spherical inclusion and screw dislocation images. It was determined that a class of Adams-multistep methods can provide a decrease in computation time ranging from 2 to 4 as compared to the standard Runge-Kutta 4(5) approach depending on the simulation conditions.

  6. Comparative histological and histochemical studies on the pancreas of Labeo rohita (Hamilton, 1822, Mystus vittatus (Bloch, 1790 and Notopterus notopterus (Pallas, 1769

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    Padmanabha Chakrabarti

    2015-01-01

    Full Text Available The histological analysis, disposition and histochemical localization of tryptophan were investigated in the pancreas to compare the cellular organization and histochemical characterization in the pancreas of Labeo rohita (Hamilton, 1822, Mystus vittatus (Bloch, 1790 and Notopterus notopterus (Pallas, 1769 having different feeding habits. Histological analysis demonstrated that the exocrine pancreatic tissues were dispersed within the hepatic parenchyma and spleen in L. rohita. Thin septa of connective tissue separated parenchyma of liver and also the spleen from exocrine pancreatic cells. However, in M. vittatus, the discrete pancreatic tissue formed distinct oval or elongated acini interspersed with small area of islet of Langerhans and blood vessels. In N. notopterus, the rhomboidal acinar cells of discrete pancreatic tissue intercalated with comparatively clear and large islet of Langerhans. The exocrine acinar cells in all the three species were provided with prominent nuclei and densely packed zymogen granules. Histochemical localization revealed that the zymogen granules of exocrine acinar cells of all species exhibited varied intensities of tryptophan reaction, the precursor of various pancreatic enzymes which may be related to the food and feeding habits of the fishes under study.

  7. A new genus of proteocephalid tapeworm (Cestoda) from the marbled swamp eel Synbranchus marmoratus Bloch (Synbranchiformes: Synbranchidae) in the River Paraná basin, Argentina.

    Science.gov (United States)

    Arredondo, Nathalia J; Alves, Philippe Vieira; Gil de Pertierra, Alicia A

    2017-05-05

    Synbranchiella gen. n. is proposed to accommodate Synbranchiella mabelae sp. n. (Proteocephalidae: Monticelliinae) from the intestine of the marbled swamp eel Synbranchus marmoratus Bloch, in the River Colastiné, a tributary of the middle River Paraná in Argentina. The new genus is placed in the Monticelliinae because of the cortical position of the genital organs. It differs from all known monticelliine genera by the following combination of characters: (i) scolex robust, with a conical apex, without metascolex; (ii) biloculate suckers with a conspicuous septum separating unequally-sized loculi and a robust non-adherent area, lacking free posterior margin; (iii) vitelline follicles in two narrow lateral bands, extended throughout the nearly entire proglottid length; (iv) vagina always anterior to the cirrus-sac, with an inconspicuous vaginal sphincter; (v) a genital pore pre-equatorial. Scanning electron microscopy revealed three types of microtriches on the tegument surface: acicular and capiliform filitriches and gladiate spinitriches. A phylogenetic analysis of the large subunit nuclear ribosomal RNA gene (lsrDNA, D1-D3 domains) confirms that S. mabelae represents an independent lineage within a large clade comprised mainly from Neotropical taxa parasitising catfishes. This is the second proteocephalidean cestode described from a Neotropical synbranchiform fish host.

  8. Darboux transformation and soliton solutions for the generalized coupled variable-coefficient nonlinear Schrödinger-Maxwell-Bloch system with symbolic computation

    Science.gov (United States)

    Guo, Rui; Tian, Bo; Lü, Xing; Zhang, Hai-Qiang; Liu, Wen-Jun

    2012-04-01

    In an inhomogeneous nonlinear light guide doped with two-level resonant atoms, the generalized coupled variable-coefficient nonlinear Schrödinger-Maxwell-Bloch system can be used to describe the propagation of optical solitons. In this paper, the Lax pair and conservation laws of that model are derived via symbolic computation. Furthermore, based on the Lax pair obtained, the Darboux transformation is constructed and soliton solutions are presented. Figures are plotted to reveal the following dynamic features of the solitons: (1) Periodic mutual attractions and repulsions of four types of bound solitons: of two one-peak bright solitons; of two one-peak dark solitons; of two two-peak bright solitons and of two two-peak dark solitons; (2) Two types of elastic interactions of solitons: of two bright solitons and of two dark solitons; (3) Two types of parallel propagations of parabolic solitons: of two bright solitons and of two dark solitons. Those results might be useful in the study of optical solitons in some inhomogeneous nonlinear light guides.

  9. Impact of Salinity on the Incubation Rate and the Performance during the Nursery Phase of Square Head Climbing Perch (Anabas testudineus Bloch, 1792

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    Le, DV.

    2016-01-01

    Full Text Available Square head climbing perch (Anabas testudineus Bloch, 1792 is a high quality fish without small bones. It grows in a wide range of temperatures (10-42 oC, pH (3.5-9.5 and salinity (up to 16%. As regards climate change, this species may become important for aquaculture in the Tam Giang-Cau Hai lagoon near Hue city. To optimise the quality of fingerlings, we analyzed the effect of salinity levels on hatching and nursing in three subsequent experiments. Fertilization, hatching, survival and growth rates for 30 days were determined at salinity levels 0%, 5%, 7%, 13% and 15%. Water temperature and pH varied between 22-29.5 oC and 7.3-7.8, respectively. Between 0-5%, fertilization ratio was 77% to 83% and highest at 5%, but this dropped to 0% when salinity increased; hatching ratio was larger than 90%, but decreased to 0% at 13-15%. Between 0-11%, hatching time of fertilized eggs was not affected by salinity levels. The ratio of deformation gradually increased above 5%. After hatching at either 0 or 5%, survival ratios for square head climbing perch were above 13% up to 5%, but dropped to 0% at 9%. The growth after 30 days of nursing was higher at 5 and 7% compared with that of 0 and 3%.

  10. Redescription of Henneguya chaudhuryi (Bajpai & Haldar, 1982) (Myxosporea: Myxobolidae), infecting the gills of the freshwater fish Channa punctata (Bloch) (Perciformes: Channidae) in India.

    Science.gov (United States)

    Chaudhary, Anshu; Molnár, Kálmán; Gupta, Abhishek; Cech, Gábor; Singh, Hridaya S; Székely, Csaba

    2017-03-01

    During a survey of myxosporean parasites of freshwater fishes in Meerut, Uttar Pradesh (UP), India, spores of Henneguya chaudhuryi (Bajpai & Haldar, 1982) were found in the gill lamellae of the spotted snakehead fish Channa punctata (Bloch) (Perciformes: Channidae). This species was described lacking several characteristics in the original description, which makes challenging the accurate diagnosis. Here, we supplemented its description based on morphological, histological and molecular data. Plasmodia of H. chaudhuryi are oval, measuring 60-100 × 40-68 µm, located intralamellarly. Mature spores are elongate, measuring 10.5-13.2 × 3.6-4.2 µm, with two slightly unequal polar capsules with 6-7 filamental turns and two straight, equal caudal appendages, 10-17 µm long. Scanning electron microscopy revealed a flat surface. The 18S rDNA sequence for H. chaudhuryi did not show a close relationship with those of any other Henneguya spp., represented in the GenBank.

  11. RESEARCHES REGARDING THE CHANGES OF SOME PHYSIOLOGICAL PARAMETERS AT THE PRUSSIAN CARP (Carassius auratus gibelio Bloch 1782 UNDER THE ACTION OF THE DUAL GOLD 960 EC HERBICIDE

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    Elena Diana Biţu

    2016-12-01

    Full Text Available Herbicides are chemical substances with selective toxic action (limited for some vegetal species or general (for any species, used to fight against weeds in the crops, fruit and grapes-growing fields, parks etc. The administration of herbicides though has complex effects on the biocenosis. In the aquatic environment, they have proved to be toxic not only for the aimed plants, but also for numerous species of animals. The deterioration of the aquatic environment is accentuated by the fact that plants that had died due to the treatment decompose themselves in a rapid manner, leading to the decrease of the oxygen level in the water, the final consequence being the increase in the death rate of the animals. This paper has studied the action of the Dual Gold 960 EC herbicide in different concentrations on some physiological indicators for the Prussian carp (Carassiusauratusgibelio Bloch 1782. The herbicide has had an inhibitive effect on the researched parameters for all the used concentrations.

  12. In vitro larvicidal activity of geraniol and citronellal against Contracaecum sp (Nematoda: Anisakidae

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    L.A. Barros

    2009-10-01

    Full Text Available Human infection with fish parasites can result from the ingestion of incompletely cooked or raw fish, giving origin to parasitic diseases such as anisakiasis, caused by parasites of the Anisakidae family. The present study assessed the in vitro larvicidal effect of two monoterpene compounds, geraniol and citronellal, against Contracaecum sp (Nematoda: Anisakidae. Four hundred live larvae of Contracaecum sp obtained from "traíra" fish (Hoplias malabaricus, Bloch, 1974 were analyzed on 40 Petri dishes (10 larvae each with the compounds to be tested. The final concentrations tested for each compound were 250, 125, 62.5, and 31.2 µg/mL and the evaluation was carried out at five different times (2, 4, 8, 24, and 48 h. The larvicidal action of geraniol and citronellal was statistically superior (P < 0.005 to the control (1% ethanol at concentrations of 250 and 31.2 µg/mL (geraniol and 250, 125, and 62.5 μg/mL (citronellal. However, no larvicidal activity was observed at concentrations of 125 and 62.5 µg/mL for geraniol and 31.2 µg/mL for citronellal. When the larvicidal action of geraniol was compared to that of citronellal, the former was found to be statistically superior (P < 0.05 to the latter at concentrations of 250 and 31.2 μg/mL. On the other hand, citronellal was statistically superior (P < 0.005 to geraniol at concentrations of 125 and 62.5 μg/mL. The larval mortality rate in terms of time (hours was higher for geraniol with the passing of time at the 250 μg/mL concentration. At this concentration (in 48 h the best larvicidal effect was observed with 90% lethality. The larvae were considered to be dead using no motility and loss of structural integrity as parameters. The data indicate that natural terpene compounds should be more explored for antihelminthic activity and can be useful for other studies about anisakiasis treatment.

  13. Response to the ration levels on growth, body composition, energy, and protein maintenance requirement of the Indian catfish (Heteropneustes fossilis-Bloch 1974).

    Science.gov (United States)

    Ahmed, Imtiaz

    2010-12-01

    An 8-week growth study was conducted to determine the effect of ration level, energy, and protein maintenance requirement of catfish, Heteropneustes fossilis-Bloch, fingerling (7.90±0.55 cm; 3.10±0.28 g) by feeding casein-gelatin-based purified diet (40% CP; 3.61 kcal g-1 GE) at six ration levels 1-6% of BW/day, at 0800 and 1700 h, in triplicate, with 20 fish per trough fitted with water flow-through system of volume 55 L. Maximum live weight gain, best feed conversion ratio (FCR), best specific growth rate (SGR), and highest protein efficiency ratio (PER) were evident for ration levels of 4-5% body weight. However, second-degree polynomial regression analysis for weight gain, FCR, PER, protein, and energy retention data indicated that the break-points occurred at 5.08, 4.18, 4.05, 4.16, and 4.17% BW/day, respectively. Significantly (P0.05) low at higher rations. Protein and energy retention values also produced significant (Pfeeding in the range of 4 to 4.5% BW/day, corresponding to 1.60-1.80 g protein and 14.46-16.27 kcal energy g100 g(-1) of the diet/day is optimum for the growth and efficient feed utilization of H. fossilis, while 2-3% ration levels (0.80-1.20 g protein and 7.23-10.84 kcal energy) suggest that these amounts approximate to the maintenance requirement of this fish.

  14. Structure of the parasites communities in two Erythrinidae fish from Amazon river system (Brazil

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    Natália Milhomem Alcântara

    Full Text Available This study compared the parasite communities of Hoplias malabaricus and Hoplerythrinus unitaeniatus from Amazon river system. Hoplias malabaricus were infected by Ichthyophthirius multifiliis, Piscinoodinium pillulare, Tetrahymena sp., Urocleidoides eremitus, Braga patagonica, metacercariae of Clinostomum marginatum, Procamallanus(Spirocamallanus inopinatus, larvae of Contracaecum sp. and larvae of Nomimoscolex matogrossensis. Hoplerythrinus unitaeniatus were also infected by these same species of protozoans, nematodes, digeneans and cestodes, except for Tetrahymena sp. and B. patagonica, which were replaced by Argulus pestifer, Urocleidoides sp., Whittingtonocotylecaetei, Whittingtonocotyle jeju and Gorytocephalus spectabilis. For both hosts, I. multifiliis and P. pillulare were the predominant parasites. Most of the parasites presented an overdispersion. Parasite species richness, Brillouin diversity, evenness and Berger-Parker dominance were similar for the two hosts. The length and weight of H. malabaricusshowed a positive correlation with the abundance of U. eremitusand Contracaecum sp., while the weight of H. unitaeniatus showed a positive correlation with the abundance of I. multifiliis. The diversity of ectoparasites seemed to be influenced by the behavior of these two hosts. This was shown by the similar parasite communities and was characterized by low species diversity, low evenness and low richness, and by a high prevalence of ectoparasites.

  15. PATHOMORPHOLOGICAL AND CYTOMETRIC PARAMETERS OF BLOOD RED CELLS OF AGE-2 PRUSSIAN CARP (CARASSIUS AURATUS GIBELIO (BLOCH, 1782 IN THE CONDITIONS OF INTOXICATION WITH COPPER IONS

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    T. Sharamok

    2017-09-01

    Full Text Available Purpose. To detect the effect of elevated copper ion concentrations (10 aquaculture Maximum Permissible Limits on morphological and cytometric parameters of erythrocytes of age-2 Prussian carp (Carassius gibelio Bloch, 1782 in experimental and natural conditions. Methodology. During the work, summarized results of studies performed in 2015-2016 were used. Morphological and cytometric parameters of Prussian carp erythrocytes were determined in the conditions of natural habitats (Zaporizhzhia reservoir and an experiment. Copper ion concentration both in the experiment and natural conditions was similar and was 0.01 mg/L (10 aquaculture Maximum Permissible Limits. Experimental studies were performed during 21 days. In the control aquarium, fish were kept in the settled tap water; while in the experimental aquaria, intoxication of fish with copper ions was modelled by introducing CuSO4 in water. Blood smears were examined under 40x and 100 x magnifications with the use of microphotography (digital camera Sciencelab T500 5.17 M. Findings. The performed hematological studies showed that under the conditions of experimental chronic intoxication with copper ions (0.01 mg/L, age-2 Prussian carp had an increase in the share of immature forms of erythrocytes, increase in the number of erythrocytes with pathological signs (cell wall destruction, atypical forms, increase in the nucleus-cytoplasm ration, but the difference in cytometric parameters of erythrocytes between experimental and control fish was not significant. When comparing the morphometric parameters of erythrocytes of fish kept in experimental and natural conditions with similar copper ion concentrations (0.01 mg/L, a significant increase in the nucleus areas of mature erythrocytes was detected and, correspondingly, an increase in the nucleus-cytoplasm ratio of erythrocytes (by almost 30% in fish in experimental conditions compared to fish, which lived in the Zaporizhzhia reservoir. An increase

  16. The taxonomic status of Japanese threadfin bream Nemipterus japonicus (Bloch, 1791) (Perciformes: Nemipteridae) with a redescription of this species from the south china sea based on morphology and DNA barcodes

    Science.gov (United States)

    Ning, Ping; Sha, Zhongli; Hebert, Paul D. N.; Russell, Barry

    2015-02-01

    Because of its importance as a food source, Nemipterus japonicus (Bloch, 1791) (Nemipteridae) or Japanese threadfin bream is the best studied of these taxa, and numerous investigations have examined its fisheries, its biology and biochemistry. Despite such intensive work, the taxonomic status of N. japonicus has never been seriously questioned and it is regarded as a common species, widely distributed throughout the Indo-Western Pacific Ocean. In fact, Bloch's description of the type specimen of N. japonicus has ambiguous collection data and lacks a designation for the type locality, though it is probably Java. In this paper, DNA barcode results based on COI gene support the existence of two geographically separated lineages of the Japanese threadfin bream, both being an Indian Ocean and western Pacific lineage, with 2.7% sequence divergence, and the results indicate a possible existing of some cryptic species. The two lineages also possess a diagnostic difference in their belly color, with specimens in the South China Sea having a silver belly, while those from the Indian Ocean isolate specimen have a yellow coloration. Based upon new collections from the South China Sea, this species from the western Pacific is morphologically redescribed and its details of DNA barcode diversity are shown for the future investigations.

  17. Diploposthe laevis (Bloch Jacobi (Eucestoda, Hymenolepididae from Netta peposaca (Vieillot (Aves: Anatidae: first record for the Neotropical Region and a new host Diploposthe laevis (Bloch Jacobi (Eucestoda: Hymenolepididae em Netta peposaca (Vieillot (Aves, Anatidae: primeiro registro para Região Neotropical e novo hospedeiro

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    Eliane F. da Silveira

    2008-03-01

    Full Text Available One hundred eight rosy-billed pochards, Netta peposaca (Vieillot, 1816, collected in Brazil and Argentina were examined for endoparasites. Collection sites included the municipalities of Santa Vitória do Palmar and Jaguarão, Rio Grande do Sul State, Brazil (wintering site and Alvear, Corrientes Province, northern Argentina (nesting site. Birds were frozen in dry ice after collection. During necropsy they were categorized according to sex and maturation, either adult or juvenile. The cestode Diploposthe laevis (Bloch Jacobi, 1896 was found (prevalence 68.5%, mean infection was 2. The mean prevalence of D. laevis in Alvear (25.9% was higher than found in Jaguarão and Santa Vitória do Palmar, Rio Grande do Sul (19%, and could be related to the nesting site and to the period when the birds may ingest a higher amount of food. This is the first record of a species of the genus Diploposthe in anatideans from South America, and the first record of the species in N. peposaca. Details of the cirrus pouch and vagina were described based on histological sections.Com o objetivo de conhecer a helmintofauna do marrecão, Netta peposaca (Vieillot, 1816, na América do Sul, 108 aves foram amostradas. Os pontos de captura foram os municípios de Santa Vitória do Palmar e Jaguarão, no Estado do Rio Grande do Sul, sul do Brasil (pólo de invernia, e em Alvear, Província de Corrientes, região norte da Argentina (pólo de nidificação, entre 2002 e 2004. As aves foram congeladas em gelo seco logo após o abate. Durante o procedimento de necropsia tiveram o sexo identificado, e foram classificadas de acordo com estado de maturação sexual, em juvenil e adulto. O cestóide Diploposthe laevis (Bloch Jacobi, 1896 foi encontrado com prevalência média de 68,5% e intensidade média de infecção de dois espécimes por hospedeiro. A prevalência média de D. laevis em Alvear (25,9% foi maior do que a encontrada em Jaguarão e Santa Vitória do Palmar, Rio Grande

  18. mRNA’S SECONDARY STRUCTURE FOR HAPLOTYPES OF THE GENE WHICH DETERMINS THE CYTOCHROME’S B SYNTHESIS, FOR CARASSIUS AURATUS GIBELIO BLOCH. 1783 INDIVIDUALS SAMPLED FROM MOVILENI AND IASI POPULATIONS

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    Lucian Gorgan

    2007-08-01

    Full Text Available : In present paper, the main purpose was to establish the mRNA’s secondary structure for the gene which determines the cytochrome’s b synthesis, for Carassius auratus gibelio Bloch. 1783 individuals, having the origin in two different populations - Movileni and Iaşi, as well as those structures’s comparison, with similar models of the same gene, taken from the GenBank, for different species and subspecies of Carassius genera. Thus, regions from mtDNA were sequenced for 10 individuals of each analyzed population, based on a purified DNA matrix, using a method with phenol : chloroform : izoamyl alcohol (25:24:1. Those genes were subsequently amplified and sequenced using two complementary universal primers, obtaining both complementary chains, which ulterior formed a unique strand.MRNA’s secondary structure transcription and modeling was made using the GeneQuest module of LaserGene’s program.

  19. Compuestos organoclorados residuales en dos especies ícticas de la Ciénaga Grande del Bajo Sinú, Córdoba, Colombia

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    Edineldo Lans C

    2011-04-01

    Full Text Available Objetivo. Determinación de niveles de pesticidas organoclorados (POCs en especies ícticas, procedentes de la Ciénaga Grande del Bajo Sinú, Materiales y métodos. Se usó un cromatógrafo de gases (Perkin Elmer Autosystem XL con detector captura de electrones y columna capilar 5% de difenil y 95% de dimetilpolisiloxano, de 30 m, 0.25 mm de diámetro interno y 0.25 μm de espesor de película. Las especies estudiadas fueron: bocachico (Prochilodus magdalenae y moncholo (Hoplias malabaricus, durante las estaciones seca y húmeda. Resultados. El porcentaje de recuperación de los pesticidas determinados se registró entre 80 y 84%, mientras que los límites de detección y cuanficación fueron 0.02 a 0.18 ng/g y 0.2 a 1.8 ng/g respectivamente. La desviación estándar relativa permaneció por debajo del 7% en todos los casos. De los pesticidas organoclorados investigados, en las dos especies se detectaron el a-clordano, endrín y aldrín. Se observó que a medida que aumenta el peso y el tamaño del pez, aumenta la concentración de los plaguicidas en una de las especies. Los niveles de concentración de los POCs estuvieron en el intervalo de 0.35-3.75 y 0.48-5.49 ng/g para el moncholo (Hoplias malabaricus and bocachico (Prochilodus magdalenae respectivamente. Conclusiones. La frecuencia de aparición de POCs y los niveles detectados en las especies podrían ser consecuencia de actividades antropogénicas realizadas en los alrededores de la ciénaga. La correlación entre las medidas biométricas y la concentración depende de la especie íctica. Las concentraciones encontradas en las especies estudiadas, Hoplias malabaricus y Prochilodus magdalenae no representan toxicidad letal inmediata.

  20. Ecologie des poissons capitaines: Polydactylus quadrifilis (Cuvier, 1829, Galeoides decadactylus (Bloch, 1795 et Pentanemus quinquarius (Linné, 1758 de la pêcherie artisanale maritime de Grand-Lahou (Côte d'Ivoire

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    Konan Kouassi, S.

    2013-01-01

    Full Text Available The Ecology of Polynemids: Poydactylus quadrifilis (Cuvier, 1829, Galeoides decadactylus (Bloch, 1795 and Pentanemus quinquarius (Linné, 1758 of the Artisanal Marine Fisheries of Grand Lahou (Ivory Coast. The ecology of Polynemids (Poydactylus quadrifilis, Galeoides decadactylus and Pentanemus quinquarius has been studied starting from the unloads of the artisanal marine fisheries of Grand Lahou (Ivory Coast. The temperature of the littoral is high during June and May with an average of 27,55±0,8 °C such as between November and December (29,30±0,1 °C. It is low between July and September (24,5±1,5 °C. On the other hand, salinity has its higher average values (35±0,8 g/l during the cold periods (July at September and lowest during the hot period, from October to January (33,9±0,3 g/l. The physiological needs of Polynemids cause seasonal migrations of the juveniles and adults. Hence the crossing of the estuary of the lagoon during the cold period, from June to August by the juveniles of Polydactylus quadrifilis and Galeoides decadactylus. For Polydactylus quadrifilis the annual recruitment of young specimens is identical to that of the adults, which is contrary to that of Galeoides decadactylus and Pentanemus quinquarius.

  1. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

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    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna

    2015-09-01

    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish.

  2. Chemical composition of lipids from native and exotic fish in reservoirs of the state of Ceará, Brazil

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    Selene Maia de Morais

    2016-08-01

    Full Text Available Current study analyzes the chemical composition of lipids in fish commonly found in the dams of the state of Ceará, Brazil, namely Pterygoplichthys pardalis (bodó, Hoplias malabaricus (traira, Cichla ocellaris (tucunaré, Prochilodus brevis (curimatã and Oreochomis niloticus (tilapia. The animals were collected during the summer and Folch extraction procedure was used for the extraction of lipids, whilst Iupac methodology (International Union of Pure and Applied Chemistry [Iupac], 1987 was used to methylate the fatty acids. Methyl esters were analyzed by GC/MS and the different components in fish oil were identified. Palmitic acid, C16:0 (35.71-45.02%, was the saturated fatty acid with the highest percentage, while oleic acid, C18:1Δ9 (10.62-25.29% had the highest percentage among the unsaturated fatty acids. The chemical composition of analyzed freshwater fish lipids revealed low levels of polyunsaturated fatty acids.

  3. Ichthyofauna from the Emas National Park region: composition and structure

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    E. Benedito-Cecilio

    Full Text Available The relationship between habitats and the ichthyofauna composition in the Parque Nacional das Emas (PNE and adjacent areas (the Araguaia and Sucuriú rivers are provided and could be applied in determining the Park's future zoning. Samples of the ichthyofauna and limnological parameters were obtained during both dry (September 1999 and wet (December 1999 seasons. Ichthyofauna collections resulted in the capture of 4,740 specimens of 22 species. The most abundant species in the Araguaia River during the two sampling seasons were Astyanax sp. 2 and Hasemania sp. In the Sucuriú River and PNE, Astyanax scabripinnis cf. paranae and Hoplias aff. malabaricus were the most frequent species. The largest number of species and diversity index were recorded for the Araguaia River. However, sound management policies require more detailed studies on the fish communities of the Cerrado biome.

  4. Records of new localities and hosts for crustacean parasites in fish from the eastern Amazon in northern Brazil.

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    Oliveira, Marcos Sidney Brito; Corrêa, Lincoln Lima; Oliveira Ferreira, Drielly; Neves, Lígia Rigor; Tavares-Dias, Marcos

    2017-06-01

    The aim of this study was to investigate parasites crustacean fauna in Arapaima gigas, Cichla monoculus, Cichla ocellaris, Cichla jariina, Satanoperca jurupari, Leporinus friderici, Leporinus fasciatus, Hoplias malabaricus, Phractocephalus hemioliopterus, Serrasalmus altispinis, Pseudoplatystoma tigrinum and Potamotrygon motoro of the State Amapá and Pará, in northern Brazil. A total of 242 parasites, including Argulus elongatus, Argulus multicolor,Argulus juparanaensis, Argulus nattereri, Dolops discoidalis, Dolops longicauda, Braga patagonica, Braga fluviatilis, Livoneca guianensis and undetermined Lernaeidae, were collected from these hosts. The Argulus species had the greatest richness among the community of parasitic crustaceans. There was a low abundance of parasites among the hosts, other than D. discoidalis, was most abundant in the integument of A. gigas and P. tigrinum. Finally, the present study reported nine new hosts for the crustacean parasite species and expanded knowledge of the occurrence of some parasite species in the Jari River basin, in eastern Amazon.

  5. Conspecific and heterospecific alarm substances induce behavioral responses in juvenile catfish Rhamdia quelen

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    Carina Vogel

    2017-04-01

    Full Text Available ABSTRACT The recognition of chemical information indicating the presence of a predator is very important for prey survival. In this study we tested antipredator behavioral response of juvenile silver catfish (Rhamdia quelen against predator odor released by two different potential predators, Hoplias malabaricus and the snake Helicops infrataeniatus, and alarm cues and disturbance cues released by conspecifics and by non-predator species, Megaleporinus obtusidens and Astyanax lacustris. We used juvenile catfish that were naive to predators. The trials consisted of a 10-min prestimulus and a 10-min post-stimulus observation period. The behavioral response displayed by silver catfish exposed to alarm cues comprised a decrease in shelter use and an increase in locomotion, and also a longer latency period before feeding. Our results showed that juvenile silver catfish can perceive chemical cues released by predators, heterospecifics and conspecifics.

  6. Freqüência alimentar na larvicultura do trairão (Hoplias lacerdae Effects of feeding frequency on larval rearing of trairao (Hoplias lacerdae

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    Ronald Kennedy Luz

    2005-10-01

    Full Text Available O experimento foi realizado com o objetivo de se desenvolver estratégias de manejo alimentar durante a larvicultura de trairão. Larvas com oito dias de vida foram contadas individualmente e alojadas na densidade de 30 larvas/L em 20 unidades experimentais com volume útil de 5 L cada. As larvas foram submetidas a quatro tratamentos de freqüência alimentar: F1 - uma vez ao dia; F2 - duas vezes ao dia; F3 - três vezes ao dia; F4 - quatro vezes ao dia, cada um com cinco repetições. A alimentação foi fornecida na mesma quantidade em todos os tratamentos. Para avaliação do crescimento dos animais, foram realizadas biometrias a cada cinco dias. Após 15 dias sob os tratamentos, quando os animais estavam com 23 dias de vida, o experimento foi encerrado, avaliando-se também as taxas de sobrevivência, de mortalidade, de canibalismo e de resistência ao estresse. Na primeira avaliação biométrica, aos 13 dias de vida, não foram encontradas diferenças significativas no crescimento das larvas submetidas às diferentes freqüências alimentares. No entanto, aos 18 e 23 dias de vida, os animais do tratamento F1 apresentaram as menores médias de comprimento e peso. Não foi encontrado efeito significativo da freqüência alimentar sobre as taxas de crescimento específico durante a larvicultura. As diferentes freqüências de alimentação impostas não influenciaram as taxas de sobrevivência, de mortalidade, de canibalismo e de resistência ao estresse, destacando-se as elevadas taxas de sobrevivência (acima de 93% obtidas durante o período de larvicultura. Portanto, pelo menos durante a criação inicial (até 23 dias de vida, as larvas de trairão podem receber manejo mais simplificado, com fornecimento de alimento apenas duas vezes ao dia, sem prejuízo ao desenvolvimento e à produção de animais.The effects of feeding management strategies on larval rearing of trairao were evaluated in this trial. Eight-d old larvae were counted and stocked in 20 experimental containers (units with volume of 5 L each, with constant aeration and temperature. The stocking density was 30 larvae/L. The following treatments (feeding frequency were used: F1 - once a day, F2 - twice a day, F3 - three times a day, F4 - four times a day, each with five replicates. Feeding rate was equal for all treatments. In order to evaluate the animal growth, some samples were collected every five days. At the end of the experiment, after 23 days, the survival, mortality, rates of cannibalism and stress resistance were also evaluated. No significant difference was observed among the growth parameters at 13 days. However, after 18 and 23 days, F1 treatment showed the lowest length and weight averages. No differences of larval specific growth rate due to the feeding frequencies were observed. No effects of feeding frequency on rates of survival, mortality, cannibalism and stress resistance were detected. The survival rates showed the highest values (93% during the experiment. Thus, trairao larvae can be fed only twice a day, with no changes on growth, at least during the initial rearing (first 23 days.

  7. Anatomy of the bucco-pharyngeal cavity of Salminus brasiliensis (Cuvier, 1817 (Pisces, Characidae, Salmininae

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    Eliane Menin

    2006-03-01

    Full Text Available The bucco-pharyngeal cavity of Salminus brasiliensis, an ichthyophagous species of fresh water, is anatomically adapted to predation. The wide buccal rift, the oral-aboral enlargement of the buccal cavity and the reduced thickness of the pharyngeal mastigatory apparatus favor the capture and deglutition of larger prey. In function of the oral and pharyngeal dentition type, pre-digestive food preparation does not occur. The pointed and curved teeth, together with the tongue which is relatively mobile, prevent the prey’s escape from the buccopharyngeal cavity. The passage of the food is facilitated by the absence of pronounced folds in the mucous membrane of this cavity and by the disposition of the oral and pharyngeal teeth. The characteristics of flat and thin lips, developed oral dentition, relatively mobile tongue, mucous membrane without folds, pharynx with denticules disposed in dentigerous areas and plates, and short and sharp gill-rackers are anatomical adaptations which are shared by S. brasiliensis and other ichthyophagous Characiformes species such as Salminus maxillosus, Salminus hilarii, Hoplias malabaricus, Hoplias lacerdae, Acestrorhynchus lacustris and Acestrorhynchus britskii. However, different to the mentioned species, except other Salmininae, S. brasiliensis possesses oral teeth of an unique type, present only in the jawbones and distributed in two series.

  8. T1-refBlochi: high resolution 3D post-contrast T1 myocardial mapping based on a single 3D late gadolinium enhancement volume, Bloch equations, and a reference T1.

    Science.gov (United States)

    Hu, Chenxi; Sinusas, Albert J; Huber, Steffen; Thorn, Stephanie; Stacy, Mitchel R; Mojibian, Hamid; Peters, Dana C

    2017-08-18

    High resolution 3D T1 mapping is important for assessment of diffuse myocardial fibrosis in left atrium or other thin-walled structures. In this work, we investigated a fast single-TI 3D high resolution T1 mapping method that directly transforms a 3D late gadolinium enhancement (LGE) volume to a 3D T1 map. The proposed method, T1-refBlochi, is based on Bloch equation modeling of the LGE signal, a single-point calibration, and assumptions that proton density and T2* are relatively uniform in the heart. Several sources of error of this method were analyzed mathematically and with simulations. Imaging was performed in phantoms, eight swine and five patients, comparing T1-refBlochi to a standard spin-echo T1 mapping, 3D multi-TI T1 mapping, and 2D ShMOLLI, respectively. The method has a good accuracy and adequate precision, even considering various sources of error. In phantoms, over a range of protocols, heart-rates and T1 s, the bias ±1SD was -3 ms ± 9 ms. The porcine studies showed excellent agreement between T1-refBlochi and the multi-TI method (bias ±1SD = -6 ± 22 ms). The proton density and T2* weightings yielded ratios for scar/blood of 0.94 ± 0.01 and for myocardium/blood of 1.03 ± 0.02 in the eight swine, confirming that sufficient uniformity of proton density and T2* weightings exists among heterogeneous tissues of the heart. In the patients, the mean T1 bias ±1SD in myocardium and blood between T1-refBlochi and ShMOLLI was -9 ms ± 21 ms. T1-refBlochi provides a fast single-TI high resolution 3D T1 map of the heart with good accuracy and adequate precision.

  9. Zymosan-induced immune challenge modifies the stress response of hypoxic air-breathing fish (Anabas testudineus Bloch): Evidence for reversed patterns of cortisol and thyroid hormone interaction, differential ion transporter functions and non-specific immune response.

    Science.gov (United States)

    Simi, S; Peter, Valsa S; Peter, M C Subhash

    2017-09-15

    Fishes have evolved physiological mechanisms to exhibit stress response, where hormonal signals interact with an array of ion transporters and regulate homeostasis. As major ion transport regulators in fish, cortisol and thyroid hormones have been shown to interact and fine-tune the stress response. Likewise, in fishes many interactions have been identified between stress and immune components, but the physiological basis of such interaction has not yet delineated particularly in air-breathing fish. We, therefore, investigated the responses of thyroid hormones and cortisol, ion transporter functions and non-specific immune response of an obligate air-breathing fish Anabas testudineus Bloch to zymosan treatment or hypoxia stress or both, to understand how immune challenge modifies the pattern of stress response in this fish. Induction of experimental peritonitis in these fish by zymosan treatment (200ngg(-1)) for 24h produced rise in respiratory burst and lysozomal activities in head kidney phagocytes. In contrast, hypoxia stress for 30min in immune-challenged fish reversed these non-specific responses of head kidney phagocytes. The decline in plasma cortisol in zymosan-treated fish and its further suppression by hypoxia stress indicate that immune challenge suppresses the cortisol-driven stress response of this fish. Likewise, the decline in plasma T3 and T4 after zymosan-treatment and the rise in plasma T4 after hypoxia stress in immune-challenged fish indicate a critical role for thyroid hormone in immune-stress response due to its differential sensitivity to both immune and stress challenges. Further, analysis of the activity pattern of ion-dependent ATPases viz. Na(+)/K(+)-ATPase, H(+)/K(+)-ATPase and Na(+)/NH4(+)-ATPase indicates a functional interaction of ion transport system with the immune response as evident in its differential and spatial modifications after hypoxia stress in immune-challenged fish. The immune-challenge that produced differential pattern

  10. Cross-species chromosome painting tracks the independent origin of multiple sex chromosomes in two cofamiliar Erythrinidae fishes

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    Trifonov Vladimir

    2011-06-01

    Full Text Available Abstract Background The Erythrinidae fish family is characterized by a large variation with respect to diploid chromosome numbers and sex-determining systems among its species, including two multiple X1X2Y sex systems in Hoplias malabaricus and Erythrinus erythrinus. At first, the occurrence of a same sex chromosome system within a family suggests that the sex chromosomes are correlated and originated from ancestral XY chromosomes that were either homomorphic or at an early stage of differentiation. To identify the origin and evolution of these X1X2Y sex chromosomes, we performed reciprocal cross-species FISH experiments with two sex-chromosome-specific probes designed from microdissected X1 and Y chromosomes of H. malabaricus and E. erythrinus, respectively. Results Our results yield valuable information regarding the origin and evolution of these sex chromosome systems. Our data indicate that these sex chromosomes evolved independently in these two closed related Erythrinidae species. Different autosomes were first converted into a poorly differentiated XY sex pair in each species, and additional chromosomal rearrangements produced both X1X2Y sex systems that are currently present. Conclusions Our data provide new insights into the origin and evolution of sex chromosomes, which increases our knowledge about fish sex chromosome evolution.

  11. Habitat preferences of common native fishes in a tropical river in Southeastern Brazil

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    Marcus Rodrigues da Costa

    Full Text Available We determined in this study the habitat preferences of seven native fish species in a regulated river in Southeastern Brazil. We tested the hypothesis that fishes differ in habitat preference and that they use stretches of the river differing in hydraulic characteristics and substrate type. We surveyed fishes in four 1-km long river stretches encompassing different habitat traits, where we also measured water depth, velocity, and substrate type. We investigated preference patterns of four Siluriformes (Loricariichthys castaneus, Hoplosternum littorale, Pimelodus maculatus, and Trachelyopterus striatulus and three Characiformes (Astyanax aff. bimaculatus, Oligosarcus hepsetus, and Hoplias malabaricus, representing approximately 70% of the total number of fishes and 64% of the total biomass. We classified fishes into four habitat guilds: (1 a slow-flowing water guild that occupied mud-sand substrate, composed of two Siluriformes in either shallow ( 8 m, L. castaneus waters; (2 a run-dwelling guild that occurs in deep backwaters with clay-mud substrate, composed of the Characiformes A. aff. bimaculatus and O. hepsetus; (3 a run-dwelling guild that occurs in sandy and shallow substrate, composed of T. striatulus; and (4 a fast-flowing guild that occurs primarily along shorelines with shallow mud bottoms, composed of H. malabaricus and P. maculatus. Our hypothesis was confirmed, as different habitat preferences by fishes appear to occur in this regulated river.

  12. Biochemical responses of two Erythrinidae fish to environmental ammonia

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    G. Moraes

    Full Text Available The non-ionized form of ammonia is very toxic to many aquatic species. It is especially important in several aspects of fish biology. A large range of organismal strategies for coping with environmental stressors is usually observed in living organisms. Among those, the responses for managing chemical stressors are well studied. The present work compares biochemical responses of two evolutionarily close species, Hoplias malabaricus and Hoplerythrinus unitaeniatus, exposed to environmental ammonia. Adult fish were submitted to 1.0 mg/L of ammonium chloride for 24 hours, and plasma ammonia and urea levels were determined. The activities of OUC enzymes OCT and ARG, and the accessory enzyme GS, were quantified in liver extract and are expressed below in mumol/min/mg of wet tissue. Increases in OUC enzymes (GS from 1.14 to 2.43, OCT from 0.81 to 1.72, and ARG from 3.15 to 4.23, plasma ammonia (from 0.95 to 1.42 mmol/L, and plasma urea (from 0.82 to 1.53 mmol/L were observed (p < 0.05 in H. malabaricus exposed to 1 mg/L of ammonia chloride. The GS in H. unitaeniatus increased from 1.43 to 1.84, however the OCT, ARG, and plasma urea from H. unitaeniatus did not change. These data indicate that each species responds differently to the same environmental stressor.

  13. Eğirdir Gölü'nde Gümüşi Havuz Balığı, Carassius gibelio (Bloch, 1782 Avcılığında Kullanılan Monofilament Fanyalı Ağların Seçiciliği

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    Bayram KORKMAZ

    2014-09-01

    Full Text Available In this study, it has been investigated that the characteristics of the selectivity of monofilament trammel nets having 50, 55, 60 mm bar length. This study was carried out on prussian carp Carassius gibelio (Bloch,1782 caught in Lake Eğirdir. An indirect method developed by Holt (1963 was used for determining the selectivity parameters. Common selection factor as SF=4.753 and common standard deviation as SD=2.347 were calculated for monofilament trammel nets. Common selection factor used of the optimum catch lengths of prussian carp in 50, 55 and 60 mm bar length were 23.77; 26.14 and 28.52 cm respectively. The optimum catch lengths were compared with lenghts at first maturity of prussian carp in Lake Eğirdir. Trammel nets of this study do not cause the overfishing on the prussian carp stock

  14. Rȇve er action : Bloch, Heidegger et Levinas (Dream and Action. Bloch, Heidegger and Levinas

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    Jan Bierhanzl

    2016-06-01

    Full Text Available In this paper, I seek to rehabilitate the category of possibility and possibility’s conversion into action that Ernst Bloch’s concept of ‘concrete utopia’ represents, in particular as he elaborated this concept in the first and third volumes of his masterpiece, The Principle of Hope. What’s at issue here in concrete terms is the articulation of wishing or of will in the form of utopian subjectivity, and the conversion of wishing and will into choice and action. One may wish many things, the choices are many, but only one of them may be wanted. How then can the indecision that is inherent to wishing be linked to an idea of decision making and acting that is not at odds with future-oriented wishing? We shall start here with a Heideggerian critique of ‘pure wishful thinking’ and draw on Bloch’s reading of this notion in an attempt to defend future-oriented wishing as expressed in utopian thought and reconcile it with a philosophy of action.

  15. Directory of Open Access Journals (Sweden)

    Kleisson S. Souza

    2013-01-01

    Full Text Available The present study was based on the analysis of spraints (n = 294 collected between December 2005 and November 2007. The importance of each type of prey was determined by absolute and relative frequency. Niche breadth was also estimated. The results were reported as mean (± SD of relative frequencies. Fish were the main prey found in spraints (57.8 ± 7.0%. Fish from Callichthyidae family were the main prey, followed by Cichlidae, the species Hoplias malabaricus and the family Characidae. The frequencies of other fish and taxa were lower than 13.9% (absolute frequency and 5.6% (relative frequency. Despite significant seasonal variations, (P = 0.001, niche breadth values were low in all seasons (0.39 ± 0.11. Therefore, Lontra longicaudis presented a narrow niche breadth as a result of consistent fish predation. Based on these data, fish with rapid movement presenting territorial behavior and benthic fish with slow movements are the most consumed. Seasonal fluctuations are caused by the increase of secondary prey in the diet during some seasons.O presente estudo foi baseado na análise das fezes (n = 294, coletadas entre dezembro de 2005 e novembro de 2007. A importância de cada tipo de presa foi determinada pela frequência absoluta e relativa. A amplitude de nicho também foi estimada. Os resultados foram reportados como média (± DP da frequência relativa. Peixes foram a principal presa encontrada nas fezes (57,8 ± 7,0%. Peixes da família Callichthyidae foram a principal presa, seguido por Cichlidae, e espécies Hoplias malabaricus e Characidae. A frequência de outros peixes e a taxa foram menores do que 13,9% (frequência absoluta e 5,6% (frequência relativa. Apesar das variações sasonais significativas, (P = 0,001 os valores de amplitude de nicho foram baixos em todas as estações baixos (0,39 ± 0,11. Portanto, Lontra longicaudis apresentou uma amplitude de nicho estreita, como resultado de uma predação consistente em peixes

  16. Morphometric parameters comparisons of the digestive tract of four teleosts with different feeding habits Comparações de parâmetros morfométricos do trato digestório de quatro teleósteos com diferentes hábitos alimentares

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    Alexssandro Geferson Becker

    2010-04-01

    Full Text Available The present study compared some morphometric parameters of the digestive tract of four teleosts with different feeding habits: traira (Hoplias malabaricus, carnivore, silver catfish (Rhamdia quelen, omnivore, hassar (Hoplosternum littorale, omnivore, and grass carp (Ctenopharyngodon idella, herbivore. The digestive tract was removed from fish collected from nature and fixed for some morphometric analyses, such as: intestinal quotient, intestinal area quotient, vilosity height, digestive somatic index, and hepatosomatic index. Grass carp showed the highest values of intestinal quotient and height vilosity. On the other hand, the intestinal area quotient was higher in traira than in the other species. The intestinal quotient can be used to estimate the feeding habit, and the intestinal area quotient, vilosity height and the relationships between digestive tract length and fish weight or digestive tract weight can provide important additional information to analyze the feeding habits.O presente estudo comparou alguns parâmetros morfométricos do trato digestório de quatro teleósteos com diferentes hábitos alimentares: traira (Hoplias malabaricus, carnivoro, jundiá (Rhamdia quelen, omnivoro, tamoatá (Hoplosternum littorale, omnivoro e carpa capim (Ctenopharyngodon idella, herbivoro. O trato digestório foi removido dos peixes coletados da natureza e em seguida fixado para algumas análises morfométricas, tais como: quociente intestinal, quociente da área intestinal, altura da vilosidade, índice digestivo somático e índice hepatossomático. Os maiores valores para o quociente intestinal e a altura das vilosidades foram encontrados em carpa capim. Por outro lado, o quociente da área intestinal foi maior na traira do que nas outras espécies. O quociente intestinal pode ser utilizado para estimar o hábito alimentar, e o quociente da área intestinal, a altura da vilosidade e as relações entre o comprimento do trato digestório e o peso

  17. First record of the Indo-Pacific areolate grouper Epinephelus areolatus (Forsskål, 1775) (Perciformes: Epinephelidae) in the Mediterranean Sea.

    Science.gov (United States)

    Rothman, Shevy B S; Stern, Nir; Goren, Menachem

    2016-01-25

    The number of alien species in the Mediterranean Sea is steadily increasing and it seems that the pace has been accelerating since the turn of the century (Galil et al. 2014). In 2015 alone five additional fish species have been reported, Epinephelus geoffroyi (Klunzinger, 1870) (Golani et al. 2015); Stolephorus indicus (van Hasselt, 1823) (Fricke et al. 2015); Sardinella gibbosa (Bleeker, 1849) (Stern et al. 2015); Mobula japanica (Müller & Henle, 1841) (Capapé et al. 2015); and Cryptocentrus caeruleopunctatus (Rüppell, 1830) (Rothman & Goren 2015). Among the ca. 100 alien fish species reported from the Mediterranean to date (Galil & Goren 2014), five Indo-Pacific species belong to the genus Epinephelus Bloch, 1793: Epinephelus coioides (Hamilton, 1822), Epinephelus fasciatus (Forsskål, 1775), Epinephelus malabaricus (Bloch and Schneider, 1804) Epinephelus merra Bloch, 1793 (Golani et al. 2013a) and Epinephelus geoffroyi (Klunzinger, 1870) (Golani et al. 2015). Additional alien Epinephelus species reported from the Mediterranean are excluded for various reasons (Golani et al. 2013b). Here we report the finding of a sixth Indo-Pacific species of this genus along the Mediterranean coast of Israel.

  18. Spatial pattern of a fish assemblage in a seasonal tropical wetland: effects of habitat, herbaceous plant biomass, water depth, and distance from species sources

    Directory of Open Access Journals (Sweden)

    Izaias M Fernandes

    Full Text Available The influence of habitat, biomass of herbaceous vegetation, depth and distance from permanent water bodies on the structure of fish assemblages of a seasonal floodplain was evaluated using data collected along 22 transects in an area of 25 km² in the floodplain of Cuiabá River, Pantanal, Brazil. Each transect was sampled for fish using throw traps and gillnets during the flood period of 2006. Multivariate multiple regression analysis and multivariate analysis of covariance indicated that depth was the only variable that affected the structure of the fish assemblage, both for quantitative data (abundance and qualitative data (presence-absence. Species such as Neofundulus parvipinnis and Laetacara dorsigera were more abundant in shallower sites (below 25 cm, while Serrasalmus maculatus and Metynnis mola were found mostly in the deepest areas (over 55 cm. However, species such as Hoplias malabaricus and Hoplerythrinus unitaeniatus occurred at all sampled depths. Although the distribution of most species was restricted to a few sites, there was a positive relationship between species richness and depth of the water body. Surprisingly, the replacement of native vegetation by exotic pasture did not affect the fish assemblage in the area, at the probability level considered.

  19. Genotoxic and mutagenic evaluation of water samples from a river under the influence of different anthropogenic activities.

    Science.gov (United States)

    Batista, Nelson Jorge Carvalho; de Carvalho Melo Cavalcante, Ana Amélia; de Oliveira, Maria Geci; Medeiros, Eugênia Cristina Nascimento; Machado, Joseane Lustosa; Evangelista, Sebastiana Ribeiro; Dias, Johnny F; Dos Santos, Carla E I; Duarte, Anaí; da Silva, Fernanda R; da Silva, Juliana

    2016-12-01

    Pollution of aquatic ecosystems is associated with the discharge of mostly industrial and urban effluents, which may cause loss of biodiversity and damage to public health. This study aims to evaluate the toxicity and mutagenicity of water samples collected in the Corrente River, a major waterway in the river basin district of Pedro II, Piauí (Brazil). This river is exposed to intense anthropogenic influence from urban, automotive mechanical and family farm waste, and it is used as the main source of water supply by the population. Water samples were collected during the rainy and dry seasons, at four sites in the Corrente River, and evaluated by physicochemical, microbiological and inorganic elements analyses. The samples were evaluated for mutagenicity using the Allium cepa test (toxicity, chromosomal aberration and micronucleus tests) and fish (Tilapia rendalli and Hoplias malabaricus). The physicochemical, microbiological and inorganic results show a large contribution to the pollution loads at collection points in the town of Pedro II, demonstrating the influence of urban pollution. The Al, Si, Ti, Cr, Ni and Cu contents were determined by PIXE. These same Corrente River water samples demonstrated mutagenic effect for A. cepa and fish, as well as toxicity in the A. cepa test. The observations of mutagenic effect may suggest that the complex mixture of agents is comprised of both clastogenic and aneugenic agents. This study also showed the need for constant monitoring in places with environmental degradation caused by urban sewage discharges. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Reproductive strategies and genetic variability in tropical freshwater fish

    Directory of Open Access Journals (Sweden)

    Maria Dolores Peres Lassala

    2007-01-01

    Full Text Available We estimated the genetic variability of nine fish species from the Brazilian upper Paraná River floodplain (Astyanax altiparanae, Hoplias malabaricus, Leporinus lacustris, Loricariichthys platymetopon, Parauchenipterus galeatus, Pimelodus maculatus, Rhaphiodon vulpinus, Roeboides paranensis and Serrasalmus marginatus based on data for 36 putative allozyme loci obtained using corn starch gel electrophoresis of 13 enzymatic systems: aspartate aminotransferase (EC 2.6.1.1, acid phosphatase (EC 3.1.3.2, esterase (EC 3.1.1.1, glycerol-3-phosphate dehydrogenase (EC 1.1.1.8, glucose-6-phosphate dehydrogenase (EC 1.1.1.49, glucose-6-phosphate isomerase (EC 5.3.1.9, Iditol dehydrogenase (EC 1.1.1.14, isocitrate dehydrogenase - NADP+ (EC 1.1.1.42, L-lactate dehydrogenase (EC 1.1.1.27, malate dehydrogenase (EC 1.1.1.37, malate dehydrogenase-NADP+ (EC 1.1.1.40, phosphoglucomutase (EC 5.4.2.2 and superoxide dismutase, (EC 1.15.1.1. The mean expected heterozygosity varied from zero to 0.147. When data from the literature for 75 species of tropical fish were added to the nine species of this study, the heterozygosity values differed significantly among the groups of different reproductive strategies. The highest mean heterozygosity was for the non-migratory without parental care, followed by the long-distance migratory, and the lowest mean was for the non-migratory with parental care or internal fecundation.

  1. Potential risks of natural mercury levels to wild predator fish in an Amazon reservoir.

    Science.gov (United States)

    da Silva, Grazyelle Sebrenski; Filipak Neto, Francisco; Silva de Assis, Helena Cristina; Bastos, Wanderley Rodrigues; de Oliveira Ribeiro, Ciro Alberto

    2012-08-01

    Mercury (Hg) is a toxic metal that bioaccumulates in aquatic organisms and along food chain. Many studies have reported the problem of mercury exposure in aquatic systems from Amazon basin, but very few have focused on the potential risks to wild fish. The present study reports the bioaccumulation of mercury and alterations in target organs of the predator fish Hoplias malabaricus (traíra) from Samuel reservoir, Amazon basin, Northern Brazil. About 18% of fish had mercury levels in muscle exceeding the safe limit for ingestion through food, established by WHO (0.5 μg Hg g(-1)). Fish were separated in two groups according to mercury bioaccumulation in liver (0.2 μg Hg g(-1)-group II) for biomarker comparisons. Catalase activity and number of macrophage centers were statistically higher in group II, confirming the potential of Hg to interfere with redox balance and to recruit defense cells to the liver. Conversely, erythrocyte nuclear alterations were less frequent in group II, indicating a more rigorous selection of erythrocytes or hormesis pattern of response. Glutathione S-transferase activity, lipid peroxidation, and histopathological analyses were not statistically different in the liver and gills of both groups. Comparison of lipid peroxidation levels of these fish with others captured in Southern Brazil during another study and the high incidence of morphological alterations in the liver and gills suggest that the bioaccumulation of mercury during continuous exposure is posing potential risks to the species.

  2. Total mercury concentrations in fish from Urrá reservoir (Sinú river, Colombia. Six years of monitoring

    Directory of Open Access Journals (Sweden)

    José Marrugo-Negrete

    2015-09-01

    Full Text Available Objective. The aim of this study was to monitor the total mercury (T-Hg concentrations in fish from the Urrá reservoir, after impoundment. Materials and methods. Five fish species at different trophic levels were sampled from 2004 to 2009 and analyzed by cold-vapor atomic absorption spectroscopy for T-Hg concentrations in muscle tissue. Water quality parameters were evaluated. Results. The highest (1.39±0.69 μg/g ww and lowest (0.15±0.02 μg/g ww T-Hg concentrations were detected in Hoplias malabaricus (piscivorous and Cyphocharax magdalenae (iliophagous/detritivorous respectively, whereas Leporinus muyscorum (omnivorous had an intermediate level (0.40±0.11 μg/g ww. The organic matter content in the water increased with time and depth, whereas dissolved oxygen and pH decreased. A covariance analysis (with fish length as a covariate shows a steady increase of T-Hg levels in all the studied species after impoundment. Conclusions. The T-Hg concentrations in the evaluated fish species, increased after impoundment. The water quality variables showed conditions favoring Hg methylation and its biomagnification, this last was evident in the fish food chain of the reservoir.

  3. Eficacia del control de larvas de vectores de la malaria con peces larvívoros nativos en San Martín, Perú

    Directory of Open Access Journals (Sweden)

    Elmer Rojas P

    2004-01-01

    Full Text Available Objetivo: Determinar la eficacia del control larvario de vectores de la malaria con peces larvívoros nativos en San Martín, Perú. Material y métodos: Estudio experimental que se llevó a cabo en las localidades de Yumbatos, Alianza y San Juan de Shanusi con ocho criaderos cada uno, identificándose las especies nativas Rivulus urophtalmus "chuina" y Pyrrulina brevis "achualillo" comparados con la eficacia ejercida por Poecilia reticulata "guppy". Se midieron variables como temperatura, pH, concentración de electrolitos en el agua, densidad de los peces y presencia de otros depredadores. Resultados: Los peces nativos alcanzaron una eficacia de 98% en el control de larvas de Anopheles, cuando se mantuvieron en densidades entre 10 y 15 peces/m²; estos peces alcanzan longitudes hasta de 8 cm, y tienen similar o mayor voracidad que Poecilia reticulata. Asimismo, se evidenció la existencia de peces depredadores, Hoplias malabaricus "fasaco" y Simbranchus marmoratus "atinga", los que se alimentan de estos peces pequeños. Conclusiones: Los peces nativos son eficaces para el control de larvas de Anopheles; asimismo, se deben tener en cuenta la existencia de otras especies depredadoras, así como la limpieza de la maleza de los criaderos para incrementar la eficacia del control.

  4. Effects of anti-inflammatory drugs in primary kidney cell culture of a freshwater fish.

    Science.gov (United States)

    Ribas, João Luiz Coelho; da Silva, Cesar A; de Andrade, Lucas; Galvan, Gabrieli Limberger; Cestari, Marta Margarete; Trindade, Edvaldo S; Zampronio, Aleksander R; de Assis, Helena C Silva

    2014-09-01

    The non-steroidal anti-inflammatory drugs are emerging contaminants in aquatic ecosystems. This study aimed to evaluate toxic effects of some representative drugs of this pharmaceutical group on primary culture of monocytic lineage of Hoplias malabaricus anterior kidney. The effects of diclofenac, acetaminophen and ibuprofen in cell viability, lipopolysaccharide (LPS)-induced NO production and genotoxicity were evaluated. Cytometry analysis CD11b(+) cells showed 71.5% of stem cells, 19.5% of macrophages and 9% of monocytes. Cell viability was lower in the ficoll compared to percoll separation. LPS-induced NO production by these cells was blocked after treatment with dexamethasone and NG-Methyl-L-Arginine (L-NMMA). Exposure of the cells to diclofenac (0.2-200 ng/mL), acetaminophen (0.025-250 ng/mL) ibuprofen (10-1000 ng/mL) reduced basal NO production and inhibited LPS-induced NO production at all concentrations after 24 h of exposure. Genotoxicity occurred at the highest concentration of diclofenac and at the intermediary concentration of acetaminophen. Genotoxicity was also observed by ibuprofen. In summary, the pharmaceuticals influenced NO production and caused DNA damage in monocytic cells suggesting that these drugs can induce immunosuppression and genotoxicity in fish. Copyright © 2014. Published by Elsevier Ltd.

  5. EVALUATION OF FISH FAUNA STOCKS IN DAMS IN SOSSEGO MIME IN CANAÃ OF CARAJÁS (EASTERN AMAZON, CAPTURED WITH THE USE OF CAST NET BEFORE THE DEPOSIT OF TAILINGS

    Directory of Open Access Journals (Sweden)

    Ivan Furtado Junior

    2016-12-01

    Full Text Available This study aims to estimate the biomass of fish stocks in the area of the dam formed by tailings of Sossego mine in Canaã dos Carajás, captured with the use of cast nets for fish. The prospecting work was carried out during the period from 29 February to 6 March 2004, 6 months after closing the dam and immediately before the disposal of waste. The average values estimated for the capture per unit area covered by cast nets (CPUA and biomass were 8.4 g m-² and 16,922.7 kg, respectively. The most representative groups of fish were minnows, with 67.7% and discus with 24.8% of the total estimated biomass. The species caught were: Moenkhausia cf. sanctaefilomenae (redeye tetra fish, Tetragonopterus cf. argenteus (white tetra fish, Tetragonopterus chalceus (red tetra fish, Aequidens viridis (cichlasoma bimaculatum Crenicichla cincta (jacunda Hoplerythrinus unitaeniatus (jeju Curimata inornata (branquinha and Hoplias malabaricus (trahira. Keywords: fishing survey; yield per unit area; biomass; tailings dam.

  6. Effects of river damming in Neotropical piscivorous and omnivorous fish: feeding, body condition and abundances

    Directory of Open Access Journals (Sweden)

    Larissa Strictar Pereira

    Full Text Available ABSTRACT The increase in abundance of small-sized fishes is common after a reservoir is formed. There is an increase in the consumption of fish, from typically piscivorous fish to opportunistic species that take advantage of abundant resources. This study aims to evaluate the effects of diet changes induced by damming on the feeding activity and condition factor of typically piscivorous (Hoplias aff. malabaricus and Oligosarcus longirostris and opportunistic (Astyanax lacustris (ex Astyanax altiparanae and Pimelodus britskii . Sampling was conducted before and after the impoundment in the Iguaçu River in the region of Salto Caxias, Paraná State, Brazil. Stomach contents were analysed by the volumetric method. Feeding activity and body condition were inferred by the mean stomach repletion index and the mean condition factor. Typically piscivorous species presented a general tendency of decreased feeding activity and increased condition factor, while opportunistic species, presented a decrease in condition and feeding activity in the most affected sites. The increase in the condition factor of piscivorous fish suggests that these species benefit by the increased abundance of small size prey fish. Some opportunist species that do not have adjustments for the piscivorous diet, regardless of the intensity of consumption and resource availability, can suffer negative reflex when adopting a piscivorous diet.

  7. Evaluation of pathogenic fungi occurrence in traumatogenic structures of freshwater fish

    Directory of Open Access Journals (Sweden)

    Fabio Caetano Oliveira Leme

    2011-04-01

    Full Text Available INTRODUCTION: Fungal infections in human skin, such as sporotrichosis, can occur after fish induced trauma. This work aimed to identify fungi in freshwater fish that are pathogenic to humans. METHODS: Extraction of dental arches from Serrassalmus maculatus (piranha and Hoplias malabaricus (wolf fish, stings from Pimelodus maculatus (mandis catfish, dorsal fin rays from Plagioscion spp. (corvina and Tilapia spp., for culture in Mycosel agar. Some cultures were submitted to DNA extraction for molecular identification by sequencing ITS-5.8S rDNA. RESULTS: Cultures identified most yeast as Candida spp., while sequencing also permitted the identification of Phoma spp. and Yarrowia lipolytica. CONCLUSIONS: While the search for S. schenckii was negative, the presence of fungus of the genera Phoma and Candida revealed the pathogenic potential of this infection route. The genus Phoma is involved in certain forms of phaeohyphomycosis, a subcutaneous mycosis caused by dematiaceous fungi, with reports of infections in human organs and systems. Traumatizing structures of some freshwater fish present pathogenic fungi and this may be an important infection route that must be considered in some regions of Brazil, since there are a large number of a fisherman in constant contact with traumatogenic fish.

  8. The effects of different predator species on antipredator behavior in the Trinidadian guppy, Poecilia reticulata

    Science.gov (United States)

    Botham, M. S.; Kerfoot, C. J.; Louca, V.; Krause, J.

    2006-09-01

    Different types of predators often elicit different antipredator responses in a common type of prey. Alternatively, some prey species may adopt a general response, which provides limited protection from many different types of predator. The Trinidadian guppy, Poecilia reticulata, is faced with a wide range of different predators throughout its range and is known to display varying levels of antipredator behavior depending on the predator assemblage. Pike cichlids, Crenicichla frenata, are regarded as the primary aquatic guppy predator in streams in the northern mountain range in Trinidad. As such, they are seen to be responsible for many of the differences in morphology, life history traits, and behavior between guppy populations from areas with few predators and those from areas with many pike cichlids. In this study we investigated how guppies responded when faced with different predator species using three common aquatic predators. We exposed shoals of ten guppies to one out of four treatments: no predator (control), pike cichlid, acara cichlid ( Aequidens pulcher), and wolf fish ( Hoplias malabaricus); and we made behavioral observations on both focal individuals and the shoal as a whole. Guppies showed significantly greater levels of predator inspection and shoaling behavior, foraged less, spent more time in the surface water, and stayed in significantly larger shoals when faced with pike cichlids than in other treatments. We discuss these results in the context of multiple predator effects.

  9. Inventario rápido de la ictiofauna en la cuenca del Bajo Pachitea, Perú

    Directory of Open Access Journals (Sweden)

    Vanessa E. Palacios

    2013-03-01

    Full Text Available El presente trabajo informa sobre la diversidad de peces en la Cuenca del Bajo Pachitea. En julio de 2005 un inventario rápido en 31 estaciones (14 ríos, 13 quebradas y 4 lagunas fue realizado. El área comprendió entre Honoria (456195E, 8830474N y Zúngaro (486747E, 8965585N entre los departamentos de Ucayali y Huánuco. Para la colecta se utilizaron redes de arrastre a la orilla, obteniéndose un total de 3967 individuos. Se identificaron 116 especies reunidos en 25 familias y 8 órdenes. La mayor riqueza la tuvieron Characiformes (59%, Siluriformes (22% y Perciformes (12%. Se registraron especies de consumo humano como: Cichla monoculus, Prochilodus nigricans, Salminus hilari, Hoplias malabaricus, Liposarcus sp., Plagioscion squamosissimus; peces ornamentales: Heros severus, Corydoras stenocephalus, Mesonauta festivus, Pyrrhulina brevis. El análisis de riqueza por tipo de hábitat indica que las quebradas fueron las que presentaron mayor número de especies (64 especies, seguidas por ríos (54 y lagunas (45. Los hábitats con mayor abundancia fueron los ríos (1934 individuos, seguidos por quebradas (1745 y lagunas (253.

  10. Composition operators between Bloch type spaces and Zygmund ...

    Indian Academy of Sciences (India)

    1Hubei Province Key Laboratory of Intelligent Robot, School of Science, Wuhan. Institute of Technology, Wuhan 430073, China. 2Wuhan Institute of Physics and Mathematics, The Chinese Academy of Science,. Wuhan 430071, China. E-mail: daijineng@163.com; ouyang@wipm.ac.cn. MS received 1 September 2009; ...

  11. Optical Control of Plasmonic Bloch Modes on Periodic Nanostructures

    NARCIS (Netherlands)

    Gjonaj, B.; Aulbach, Jochen; Johnson, P.M.; Mosk, Allard; Kuipers, L.; Lagendijk, Aart

    2012-01-01

    We study and actively control the coherent properties of surface plasmon polaritons (SPPs) optically excited on a nanohole array. Amplitude and phase of the optical excitation are externally controlled via a digital spatial light modulator (SLM) and SPP interference fringe patterns are designed and

  12. ( ucleus rofeno (Bloch s assay ofos to ) using y

    African Journals Online (AJOL)

    SAM

    et al., 2011a). Fishes are considered as sensitive organism in toxicity studies and can play a significant role in assessing potential risks associated with contamination in aquatic environment by environmental contaminants. Fishes can respond to mutagens at low concentrations of toxicants in a manner similar to higher ...

  13. Equivalent moduli of continuity, Bloch's theorem for pluriharmonic ...

    Indian Academy of Sciences (India)

    where C is a positive constant which depends only on f (see [13]). Dyakonov [8] characterized the holomorphic functions in ω in terms of their modulus. Later in Theorems A and B of [22], Pavlovic came up with a relatively simple proof of the results of Dyakonov. Recently, many authors considered this topic and generalized.

  14. Generalization of the Bloch-Messiah-Zumino theorem

    Science.gov (United States)

    Dobaczewski, J.

    2000-07-01

    It is shown how to construct a basis in which two arbitrary complex antisymmetric matrices C and C' acquire simultaneously canonical forms. The present construction is not restricted by any conditions on the properties of the C+C' matrix. Canonical bases pertaining to the generator-coordinate-method treatment of many-fermion systems are discussed.

  15. Biochemical composition of the alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

    Science.gov (United States)

    Sanaye, Sushant Vilas; Pawar, Ashwini Pandurang; Rivonker, Chandrasheker Umanath; Sreepada, Rayadurga Anantha; Ansari, Zakir Ali; Ram, Anirudh

    2017-11-01

    Considering the economic importance in traditional Chinese medicine (TCM) and lack of baseline information, we evaluated the proximate composition, fatty acid and amino acid profiles, trace element content and C:N ratio in the alligator pipefish, Syngnathoides biaculeatus. Amongst proximate principals, a crude protein formed the major biochemical component ((58.9±2.2)% dry weight). Mean percent concentrations (dry weight) of other components such as a total lipid (TL), ash and nitrogen-free extract measured were, (1.8±0.2)%, (19.2±2.2)% and (20.1±0.45)%, respectively. The fatty acid profile revealed the presence of 27 saturated fatty acids (SFA) with 13 straight-chained and 14 branched-chained, 28 unsaturated fatty acids (UFA) with 14 monounsaturated and 14 polyunsaturated and nine other minor fatty acids. Mean percent contributions of total SFAs and UFAs to TL were found to be (55.41±0.24)% and (44.05±0.25)%, respectively. Altogether, 16 different amino acids with an equal number of essential (EAA) and non-essential (NAA) ones were identified. Percent contributions by EAA and NAA to the total amino acid content were 38.11% and 61.89%, respectively. Trace metal concentrations in S. biaculeatus were generally low and their distribution followed the order, Mg>Fe>Zn>Mn>Cu>Cr>Ni>Hg>Co. The C:N ratio was (4.37±0.04)%. The profile of major biochemical constituents in alligator pipefish, S. biaculeatus revealed its potential use in TCM as well as a nutritional diet for human consumption. The results of the study would also form the basis for formulation and optimization of diets for the culture of S. biaculeatus.

  16. Bloch Electron in a Magnetic Field and the Ising Model

    Science.gov (United States)

    Krasovsky, I. V.

    2000-12-01

    The spectral determinant det\\(H-ɛI\\) of the Azbel-Hofstadter Hamiltonian H is related to Onsager's partition function of the 2D Ising model for any value of magnetic flux Φ = 2πP/Q through an elementary cell, where P and Q are coprime integers. The band edges of H correspond to the critical temperature of the Ising model; the spectral determinant at these (and other points defined in a certain similar way) is independent of P. A connection of the mean of Lyapunov exponents to the asymptotic (large Q) bandwidth is indicated.

  17. Clipboard: Etroplus suratensis (Bloch), the State Fish of Kerala

    Indian Academy of Sciences (India)

    Permanent link: http://www.ias.ac.in/article/fulltext/jbsc/037/06/0925-0931. Keywords. Etroplus suratensis; breeding; raceway; enclosure farming; sanctuary. Author Affiliations. K G Padmakumar1 L Bindu1 P S Manu1. Kerala Agricultural University, Regional Agricultural Research Station, Kumarakom, Kerala 686 566, India ...

  18. On history and salvation in Emmanuel Levinas and Ernst Bloch

    African Journals Online (AJOL)

    p1243322

    introduces a future which is novel and that cannot be captured in, or reduced to, an all-encompassing synthesis. ... each other in time, and each instant has a novel quality, such that discontinuity is allowed for within ... remain a subject in which every adventure would revert into the adventure of a fate”.22. Let us now look in ...

  19. Equivalent moduli of continuity, Bloch's theorem for pluriharmonic ...

    Indian Academy of Sciences (India)

    Department of Mathematics, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China; Department of Mathematics and Computational Science, Hengyang Normal University, Hengyang, Hunan 421008, People's Republic of China; Department of Mathematics, Indian Institute of Technology Madras, ...

  20. ( ucleus rofeno (Bloch s assay ofos to ) using y

    African Journals Online (AJOL)

    SAM

    EC50) with product name CELCRON (manufactured by EXCEL. Crop Care Ltd. ... a sim valid this indire. MN i. 2003 genot pollut riment period e fish speci mentioned t ol groups at analysis in ol and expos ficant in the f the highest M at 96 h (3.65.

  1. Biochemical composition of the alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785)

    Science.gov (United States)

    Sanaye, Sushant Vilas; Pawar, Ashwini Pandurang; Rivonker, Chandrasheker Umanath; Sreepada, Rayadurga Anantha; Ansari, Zakir Ali; Ram, Anirudh

    2016-12-01

    Considering the economic importance in traditional Chinese medicine (TCM) and lack of baseline information, we evaluated the proximate composition, fatty acid and amino acid profiles, trace element content and C:N ratio in the alligator pipefish, Syngnathoides biaculeatus. Amongst proximate principals, a crude protein formed the major biochemical component ((58.9±2.2)% dry weight). Mean percent concentrations (dry weight) of other components such as a total lipid (TL), ash and nitrogen-free extract measured were, (1.8±0.2)%, (19.2±2.2)% and (20.1±0.45)%, respectively. The fatty acid profile revealed the presence of 27 saturated fatty acids (SFA) with 13 straight-chained and 14 branched-chained, 28 unsaturated fatty acids (UFA) with 14 monounsaturated and 14 polyunsaturated and nine other minor fatty acids. Mean percent contributions of total SFAs and UFAs to TL were found to be (55.41±0.24)% and (44.05±0.25)%, respectively. Altogether, 16 different amino acids with an equal number of essential (EAA) and non-essential (NAA) ones were identified. Percent contributions by EAA and NAA to the total amino acid content were 38.11% and 61.89%, respectively. Trace metal concentrations in S. biaculeatus were generally low and their distribution followed the order, Mg>Fe>Zn>Mn>Cu>Cr>Ni>Hg>Co. The C:N ratio was (4.37±0.04)%. The profile of major biochemical constituents in alligator pipefish, S. biaculeatus revealed its potential use in TCM as well as a nutritional diet for human consumption. The results of the study would also form the basis for formulation and optimization of diets for the culture of S. biaculeatus.

  2. La pesca artesanal en la Cuenca del Plata (Argentina y sus implicancias en la conservación de la biodiversidad Artisanal fish at del Plata basin (Argentina and its implications for the biodiversity conservation

    Directory of Open Access Journals (Sweden)

    Juan Miguel Iwaszkiw

    2011-06-01

    Full Text Available El objetivo del presente trabajo es considerar distintos aspectos que surgen del análisis de las exportaciones pesqueras provenientes de la pesca comercial artesanal de la Cuenca del Plata, Argentina. Se trata de identificar aquellos impactos vinculados a las prácticas pesqueras sobre las poblaciones naturales involucradas y los compromisos relacionados con la conservación de la biodiversidad de la ictiofauna de la cuenca. Se analizan 17 años de datos de las pesquerías comerciales artesanales correspondientes al tramo argentino del río Paraná sobre registros oficiales de los productos pesqueros exportados para distintas especies durante el período 1994-2010. Los registros de los productos exportados expresados en toneladas en peso (ton se refieren particularmente a especies autóctonas de gran tamaño e interés comercial como el sábalo (Prochilodus lineatus, la boga (Leporinus obtusidens, la tararira (Hoplias malabaricus, el surubí (Pseudoplatystoma spp., el dorado (Salminus brasiliensis y el patí (Luciopimelodus pati, además de varias especies acompañantes en las capturas como bagres, armados y pejerreyes (Odontesthes bonariensis. Las exportaciones pesqueras muestran un incremento sumamente importante con un total de 331.517 ton para el período 1994-2010. La especie blanco de la pesquería es el sábalo con 88,77 % de las exportaciones totales y le siguen en orden de importancia la tararira con el 4,16 %, la boga con el 3,70 %, el patí con un 1,35 % y otras especies de menor captura. Los países de destino de los productos pesqueros son Brasil, Colombia, Bolivia y Nigeria, entre otros. Sin embargo, desde el 2003, Colombia compra en promedio el 50 % del total de las exportaciones pesqueras de la Argentina. El análisis de los datos históricos de las exportaciones pesqueras (1994-2010 evidencia la necesidad de implementar medidas mas claras sobre el control y manejo de los recursos pesqueros y las posibles implicancias derivadas

  3. Evaluation of pathogenic fungi occurrence in traumatogenic structures of freshwater fish Avaliação da ocorrência de fungos patogênicos em estruturas traumatogênicas de peixes fluviais

    Directory of Open Access Journals (Sweden)

    Fabio Caetano Oliveira Leme

    2011-04-01

    Full Text Available INTRODUCTION: Fungal infections in human skin, such as sporotrichosis, can occur after fish induced trauma. This work aimed to identify fungi in freshwater fish that are pathogenic to humans. METHODS: Extraction of dental arches from Serrassalmus maculatus (piranha and Hoplias malabaricus (wolf fish, stings from Pimelodus maculatus (mandis catfish, dorsal fin rays from Plagioscion spp. (corvina and Tilapia spp., for culture in Mycosel agar. Some cultures were submitted to DNA extraction for molecular identification by sequencing ITS-5.8S rDNA. RESULTS: Cultures identified most yeast as Candida spp., while sequencing also permitted the identification of Phoma spp. and Yarrowia lipolytica. CONCLUSIONS: While the search for S. schenckii was negative, the presence of fungus of the genera Phoma and Candida revealed the pathogenic potential of this infection route. The genus Phoma is involved in certain forms of phaeohyphomycosis, a subcutaneous mycosis caused by dematiaceous fungi, with reports of infections in human organs and systems. Traumatizing structures of some freshwater fish present pathogenic fungi and this may be an important infection route that must be considered in some regions of Brazil, since there are a large number of a fisherman in constant contact with traumatogenic fish.INTRODUÇÃO: Infecções fúngicas na pele humana (como a esporotricose podem se manifestar após traumatismos por peixes. O objetivo deste trabalho é procurar fungos patogênicos para o homem em peixes fluviais. MÉTODOS: Extração de arcadas dentárias Serrassalmus maculatus (piranha e Hoplias malabaricus (traíra, ferrões de Pimelodus maculatus (mandis, raios da nadadeira dorsal de Plagioscion spp. (corvina e Tilapia spp. para a realização do cultivo em agar Mycosel. Algumas culturas foram submetidas à extração de DNA para a identificação molecular pelo seqüenciamento da região ITS-5.8S do rDNA. RESULTADOS: As culturas mostraram que a maioria das

  4. Food resources used by three species of fish in the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Márcio J. da Silva

    2010-01-01

    Full Text Available Temporary and semi-permanent aquatic habitats in semi-arid Brazil have been reported as important sites supporting a diverse fish fauna. As such, they must be able to trophically sustain fish species that feed at different trophic levels. This study aims to describe the diets of Astyanax aff. bimaculatus, Hoplias malabaricus and Prochilodus brevis in aquatic systems in semi-arid Brazil, providing evidence of the importance of these habitats as supporters of large consumers like fish. The diet of the three species studied was diverse, feeding on a range of food items, from microalgae to fish. Despite that, a few items were more important to each of the study species. These results and the relatively high rates of stomach fullness indicate that a diverse and abundant food range is available in the study sites, but species seem to select some food resources. The present study provides evidence that despite being highly variable, intermittent and semi-permanent aquatic systems in semi-arid Brazil are able to trophically sustain large consumers.Os ambientes aquáticos temporários e semi-permanentes do semiárido brasileiro tem sido mostrados como importantes sítios que possuem uma diversa fauna de peixes. Desta forma, esses ambientes devem ser capazes de sustentar, do ponto de vista trófico, populações de peixes que se alimentam em diversos níveis tróficos. O presente estudo tem como objetivo descrever o hábito alimentar de Astyanax aff. bimaculatus, Hoplias malabaricus e Prochilodus brevis em ambientes aquáticos do semiárido brasileiro, fornecendo evidências da importância desses habitats para manutenção da diversidade de consumidores como os peixes. A composição da dieta das espécies estudadas foi diversificada, já que alimentaram-se de uma variedade de classes de itens, desde microalgas até peixes. Apesar disso, alguns itens foram mais importantes para cada uma das três espécies. Estes resultados, e as altas taxas de reple

  5. Effects of experimental infections with larvae of Eustrongylides ignotus Jäegerskiold, 1909 and Contracaecum multipapillatum (Drasche, 1882 Baylis, 1920 in rabbits Efeitos de infecções experimentais em coelhos com larvas de Eustrongylides ignotus Jäegerskiold, 1909 e Contracaecum multipapillatum (Drasche, 1882 Baylis, 1920

    Directory of Open Access Journals (Sweden)

    L.A. Barros

    2004-06-01

    Full Text Available Rabbits were infected per os with 10 Eustrongylides ignotus L4 and with 50 Contracaecum multipapillatum L3 per rabbit, recovered from naturally infected freshwater fishes (Hoplias malabaricus in order to evaluate the patogenicity of these two nematode species in mammalian host. Two rabbits (20% infected with E. ignotus died before the fourth day post-inoculation (one after 51 and the other after 78 hours. Six rabbits (60% were inappetent until the fifth day following experimental inoculation. No clinical signs in rabbits inoculated with C. multipapillatum were observed; nevertheless, eight (80% animals were positive for this nematode species. Rabbits inoculated with E. ignotus, had gastric congestion with hematoma of the gastric wall in 60% of the cases. Peritoneum was congested in 20% of the animals with the presence of peritoneal abscess in 10% of the cases. All inoculated animals showed hyperemia of the gastric mucosa with hemorrhagic gastritis due to infections with E. ignotus. In C. multipapillatum inoculated animals, the hyperemia was followed by disruption of the epithelial mucosa in the sites of parasite attachment. In the gastric mucosa, miscellaneous leukocitary infiltrates, with multifocal necrosis reaching the submucosa in the infections with C. multipapillatum were observed under bright field microscopy. Perforating lesions in several organs, mainly in the gastric wall, pancreas and liver, always in the presence of a mixed inflammatory process, intensely fibrous, with hemorrhage and necrosis were observed in animals infected with E. ignotus.Coelhos foram infectados experimentalmente per os com 10 larvas L4 de Eustrogylides ignotus (n= 10 e 50 L3 de Contracaecum multipapillatum (n= 50 coletados em traíras (Hoplias malabaricus naturalmente parasitadas a fim de se avaliar a patogenicidade induzida por essas espécies de nematóides em mamíferos. Dois coelhos (20% infectados com E. ignotus morreram antes do quarto dia p

  6. Mercury pollution by gold mining in a global biodiversity hotspot, the Choco biogeographic region, Colombia.

    Science.gov (United States)

    Palacios-Torres, Yuber; Caballero-Gallardo, Karina; Olivero-Verbel, Jesus

    2018-02-01

    Mercury (Hg) is a harmful pollutant released into the environment from gold mining activities, representing a risk to human health and the ecosystems. The aim of this study was to assess the levels of total Hg (T-Hg) in human hair, fish, sediments and air; and to determine fish consumption-based risks for T-Hg ingestion in the Choco biogeographic region, a global biodiversity hotspot located at the Colombian Pacific. Mercury concentrations in hair were measured in two locations, Quibdo, the state capital, and Paimado, a riverine community. The median T-Hg value in human hair in Quibdo was 1.26 μg/g (range: 0.02-116.40 μg/g), whereas in Paimado it was 0.67 μg/g (range: 0.07-6.47 μg/g). Mercury levels in examined locations were weakly associated with height (ρ = 0.145, P = 0.024). Air T-Hg levels in Quibdo were high inside gold shops being up to 200.9-fold greater than the background. Mercury concentrations in fish from Atrato River were above WHO limit (0.5 μg/g), with highest levels in Pseudopimelodus schultzi, Ageneiosus pardalis, Sternopygus aequilabiatus, Rhamdia quelen and Hoplias malabaricus, whereas the lowest appeared in Cyphocharax magdalenae and Hemiancistrus wilsoni. Based on fish consumption, these last two species offer low risk to human health. Sediment samples from fifty different sites of Atrato River showed low T-Hg concentrations, with little variability between stations. However, contamination factors revealed a moderate pollution in 44% of sampling sites along the river. In conclusion, Hg pollution is widespread in the Biogeographic Choco and governmental actions must be taken to protect the population and preserve its biodiversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. The Canal da Piracema at Itaipu Dam as a fish pass system

    Directory of Open Access Journals (Sweden)

    Sérgio Makrakis

    Full Text Available The Canal da Piracema is the longest (nearly 10 km fish pass system in the world. The construction of this fish pass was somehow controversial, because it connected two distinct ichthyofaunistic provinces. This study evaluated the ichthyofauna present in the Canal da Piracema and the abundance and distribution of long-distance migratory fish species along this fish pass system (evaluated possible selectivity. The Canal da Piracema was shown to be difficult to sample because of its environmental heterogeneity: artificial ponds, ladders and nature-like fish pass. To solve this problem, we used several fishing gears, adequate for the several biotopes present (unstructured and structured littoral were sampled with seining nets and electrofishing; lentic were sampled with gillnets and longlines (deeper areas; and rapid water areas were sampled with cast nets. The ichthyofauna of the Canal da Piracema followed the pattern for South America and the Paraná River, with a predominance of Characiformes and Siluriformes. The most representative families were Characidae, Anostomidae, Pimelodidae and Loricariidae. We captured 116 species (17 were long-distance migratory during the period studied. Small-sized species were predominant in unstructured and structured littoral areas, especially Bryconamericus exodon and Apareiodon affinis.The most abundant species was Hypostomus spp. in lentic areas, followed by Iheringichthys labrosus. Hoplias aff. malabaricus predominated in deeper lentic areas. Long-distance migratory species were abundant in rapid waters; they were Prochilodus lineatus and Leporinus elongatus. The sharp reduction in the number of species, including migratory ones, is an indication that the Canal da Piracema is selecting the species that ascend it. Therefore, the search for information on the efficiency of the various fish passes present in the Canal da Piracema is fundamental, to facilitate upward movements of fish. If this is reached, this

  8. MEMORIAS III Encuentro Científico de Estudiantes de Biología

    Directory of Open Access Journals (Sweden)

    Acta Biológica Colombiana

    2003-12-01

    de biomasa por una colonia de atta laevigatasmith 1958 (hymenoptera: formicidae en los Llanos Orientales (Puerto López, Meta, Colombia / Manejo ex situde crías de crocodylus intermedius(crocodylidae, una experiencia como estudiante de práctica académica / Caracterización del llamado de advertencia de colostethus bocagei(amphibia: dendrobatidae en el municipio de Ibagué, Colombia / Caracterización del llamado de advertencia de colostethus bocagei(amphibia: dendrobatidae en el municipio de Ibagué, Colombia / Uso etnomédico de algunas especies vegetales del departamento del Chocó, Colombia / Morfología y herbivoría en las especies del género tococa(melastomataceae con mirmecomacios / Fauna Asociada a la Medicina Tradicional del Departamento Del Chocó, Colombia / Hongos alucinógenos: el desconocimiento cultural de su consumo / Relación insecto-hongo: desarrollo de dípteros en panaeolus foenisecii (basidiomycotina-agariclaes / Estudio preliminar de algunos aspectos biológicos de hoplias malabaricusbloch 1794 (Quicharo en la microcuenca de Cabí, Chocó, Colomba / Composición y estructura de la vegetación terrestre aledaña al Río Gaira (Departamento Del Magdalena, Colombia / Relaciones de herbivoría por insectos sobre Lantana sp. (Verbenacea, Piper sp.(Piperaceae y Miconia sp.(Asteraceae en Moniquirá (Boyacá, Colombia.

  9. Feeding biology of the hottentot, Pachymetopon blochH (Val.), with ...

    African Journals Online (AJOL)

    1987-10-13

    Oct 13, 1987 ... trends were marked. A progressive change in diet occurs with fish size, larger individuals consuming progressively more algae. The hottentot diet differs from those of a number of co-occuring sparids in being far more generalized. Hottentot feed throughout the diel cycle, although feeding activity is markedly ...

  10. Stratégies de reproduction du poisson-chat Synodontis schall (Bloch ...

    African Journals Online (AJOL)

    La reproduction du poisson-chat Synodontis schall a été étudiée en milieux lacustre et fluviatile, respectivement dans les rivières Bia et Agnébi. Le caractère permanent de l\\'eau, dans le lac a favorisé une plus grande période de reproduction de l\\'espèce dans la retenue, contrairement aux zones fluviatiles sujettes à des ...

  11. Hepatic Cytochrome P450 as Biomarkers of Cypermethrin Toxicity in Freshwater Teleost, Channa punctatus (Bloch

    Directory of Open Access Journals (Sweden)

    Dawa Bhutia

    2015-02-01

    Full Text Available In this study, Channa punctatus was treated with sub-lethal concentration of cypermethrin (6.6 µg/L for 5, 10 and 15 days and its effect on total CYP 450 and the activity of hepatic CYP450 isoforms measured. Total CYP450 content and CYP1A mediated EROD activity was significantly induced (p<0.05 in all three treated groups compared to control whereas only 15 days treated group showed significant induction in CYP2B mediated N,Ndimethylaniline demethylase activity. CYP2E1 mediated aniline hydroxylase activity showed only a marginal increase while there was inhibition of CYP3A4 mediated erythromycin demethylase activity. Liver somatic index (LSI also showed a marginal increase in all the treated groups. Results showed differential induction of CYP1A, CYP2B, CYP2E1 and inhibition of CYP3A4 isoform due to cypermethrin treatment in C. punctatus. The study clearly showed CYP1A isoform as the most responsive and important biomarker for monitoring the aquatic pollution.

  12. Dental treatment considerations for a pediatric patient with incontinentia pigmenti (Bloch-Sulzberger syndrome)

    Science.gov (United States)

    Chen, Amy Yi-Ling; Chen, Kevin

    2017-01-01

    Incontinentia pigmenti (IP) is a uncommon gene disorder, heritage with X-linked dominant mode. IP patients have a characteristic dentition varying from marked hypodontia to delayed eruption and conical crowns on both dentitions. A 5½-year-old girl, whose mother and younger sister were also diagnosed with IP, has the whirling-like pigmented skin lesion over her trunk and four extremities. Four primary teeth and multiple permanent tooth germs were found to be congenital missing. Dental considerations of further treatment were discussed with her parents including the preservation of primary molars, possible interim prosthesis in mixed or permanent dentition, full mouth rehabilitation with orthodontic and prosthodontic combined treatment, and implant therapy in adulthood. Early and longitudinal involvement of pediatric dentist to deal with the dental complications of IP can not only solve the esthetic problem and oral function but also maintain the oral health of children with IP to adulthood. PMID:28729805

  13. Near-field imaging of light propagation in photonic crystal waveguides: Explicit role of Bloch harmonics

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Volkov, V.S.; Søndergaard, Thomas

    2002-01-01

    We employ a collection scanning near-field optical microscope (SNOM) to image the propagation of light at telecommunication wavelengths along straight and bent regions of silicon-on-insulator photonic crystal waveguides (PCWs) formed by removing a single row of holes in the triangular 410-nm...

  14. Enhanced Spontaneous Emission of Bloch Oscillation Radiation from a Single Energy Band

    Science.gov (United States)

    2006-06-30

    Schomburg, S. Brandl, O. Kus, K. F. Renk , M. C. Wanke, S. J. Allen, A. A. Ignatov, V. Ustinov, A. Zhukov, and P. S. Kop’ev, Appl. Phys. Lett. 77, 1259 (2000...J. Grenzer, S. Brandl, I. Lingott, A. A. Ignatov, K. F. Renk , D. G. Pavel’ev, Yu. Koschurinov, B. Ya. Melzer, V. M. Ustinov, S. V. Ivanov, A. Zhukov...Rodwell, Phys. Rev. Lett. 76, 2973 1996. 9 S. Vinnerl, E. Schomburg, S. Brandl, O. Kus, K. F. Renk , M. C. Wanke, S. J. Allen, A. A. Ignatov, V

  15. Classification of "Quaternionic" Bloch-Bundles. Topological Quantum Systems of Type AII

    Science.gov (United States)

    De Nittis, Giuseppe; Gomi, Kiyonori

    2015-10-01

    We provide a classification of type AII topological quantum systems in dimension d = 1, 2, 3, 4. Our analysis is based on the construction of a topological invariant, the FKMM-invariant, which completely classifies "Quaternionic" vector bundles ( a.k.a. "symplectic" vector bundles) in dimension . This invariant takes value in a proper equivariant cohomology theory and, in the case of examples of physical interest, it reproduces the familiar Fu-Kane-Mele index. In the case d = 4 the classification requires a combined use of the FKMM-invariant and the second Chern class. Among the other things, we prove that the FKMM-invariant is a bona fide characteristic class for the category of "Quaternionic" vector bundles in the sense that it can be realized as the pullback of a universal topological invariant.

  16. Kuhu kadus antropoloogia? : ehk vajadus "inimloomuse" järele / Maurice Bloch ; tlk. Maarja Kaaristo

    Index Scriptorium Estoniae

    Bloch, Maurice

    2007-01-01

    Antropoloogia kui distsipliini akadeemilisest ajaloost, sotsiaal- ja kultuuriantropoloogia hariduse puudujääkidest. Antropoloogia põhilistest uurimisteemadest ja uurimisteooriatest: difusionismist, evolutsionismist ning funktsionalismist

  17. Electronic states in crystals of finite size quantum confinement of bloch waves

    CERN Document Server

    Ren, Shang Yuan

    2017-01-01

    This book presents an analytical theory of the electronic states in ideal low dimensional systems and finite crystals based on a differential equation theory approach. It provides precise and fundamental understandings on the electronic states in ideal low-dimensional systems and finite crystals, and offers new insights into some of the basic problems in low-dimensional systems, such as the surface states and quantum confinement effects, etc., some of which are quite different from what is traditionally believed in the solid state physics community. Many previous predictions have been confirmed in subsequent investigations by other authors on various relevant problems. In this new edition, the theory is further extended to one-dimensional photonic crystals and phononic crystals, and a general theoretical formalism for investigating the existence and properties of surface states/modes in semi-infinite one-dimensional crystals is developed. In addition, there are various revisions and improvements, including us...

  18. Antimicrobial activity of different tissues of snakehead fish Channa striatus (Bloch

    Directory of Open Access Journals (Sweden)

    Pravin Kumar N

    2012-05-01

    Full Text Available Objective: The aim of this study was to identify the presence of antimicrobial activity in different organs/tissues (gills, blood, skin, liver, intestine, kidney, tissue and ovary extract of snakehead fish Channa striatus. Methods: A total of 48 fractions from the organs and tissue extracts were obtained by solid-phase extraction and the fractions were assayed for antimicrobial activity. The screening of antimicrobial activity for all the fractions were tested against 8 human pathogens including Gram positive (Methicillin-resistant Staphylococcus aureus (MRSA, Staphylococcus aureus, Bacillus cereus and Gram negative bacteria (Salmonella enteritidis, Shigella flexneri, Acinetobacter baumanni, Escherichia coli, Klebsiella pneumoniae using the British Society for Antimicrobial Chemotherapy (BSAC standardized disc susceptibility test method. The activity was measured in terms of zone of inhibition in mm. Results: The results indicated that, among the 8 organs/tissues tested only blood and gills extract fractions (40 and 60 % ACN fraction showed inhibition against Escherichia coli and 60 % ACN fraction of gill extract showed inhibition against Salmonella enteritidis. Protein profile analysis by SDS-PAGE showed that antimicrobial activity of the partially purified blood and gill tissue extracts might be due to low molecular weight peptides. Conclusions: The present study showed that, gill and blood extracts of Channa striatus can be a potential source of an antimicrobial protein for specific human pathogens.

  19. Optimization of artificial fertilization in the stinging catfish Heteropneustes fossilis (Bloch).

    Science.gov (United States)

    Christopher, J Godwin; Murugesan, A G; Sukumaran, N

    2011-02-01

    Determination of optimum sperm requirement in artificial breeding helps to improve the fertilization efficiency, sperm economy and minimize the sacrificing of males for milt. Quantification of sperm cells was done by spectrophotometer at 420 nm followed by haemocytometer counting. Best correlation (r2 = 0.97) was recorded. The minimum number of sperm required for optimal fertilization success in Heteropneustes fossilis was determined. An average fertilization success of 78-93% was recorded at 8 × 103 to 8 × 107 sperm per egg. The optimum contact duration of gametes was 5 minutes. The highest fertilization rate of 98.18% was recorded at 8 × 107 spermatozoa.egg-1.

  20. Bloch-Wave Engineered Submicron Diameter Micropillars with Quality Factors Exceeding 10,000

    DEFF Research Database (Denmark)

    Hofling, S.; Lermer, M.; Gregersen, Niels

    2011-01-01

    Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed.......Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed....

  1. Reducing disorder-induced losses for slow light photonic crystal waveguides through Bloch mode engineering

    DEFF Research Database (Denmark)

    Mann, Nishan; Combrié, Sylvian; Colman, Pierre

    2013-01-01

    We present theory and measurements ofdisorder-induced losses for low loss 1.5 mmlong slow light photonic crystal waveguides. A recent class of dispersion engineered waveguides increases the bandwidth of slow light and shows lower propagation losses for the same group index. Our theory and experim...

  2. Controlled Population of Floquet-Bloch States via Coupling to Bose and Fermi Baths

    Directory of Open Access Journals (Sweden)

    Karthik I. Seetharam

    2015-12-01

    Full Text Available External driving is emerging as a promising tool for exploring new phases in quantum systems. The intrinsically nonequilibrium states that result, however, are challenging to describe and control. We study the steady states of a periodically driven one-dimensional electronic system, including the effects of radiative recombination, electron-phonon interactions, and the coupling to an external fermionic reservoir. Using a kinetic equation for the populations of the Floquet eigenstates, we show that the steady-state distribution can be controlled using the momentum and energy relaxation pathways provided by the coupling to phonon and Fermi reservoirs. In order to utilize the latter, we propose to couple the system and reservoir via an energy filter which suppresses photon-assisted tunneling. Importantly, coupling to these reservoirs yields a steady state resembling a band insulator in the Floquet basis. The system exhibits incompressible behavior, while hosting a small density of excitations. We discuss transport signatures and describe the regimes where insulating behavior is obtained. Our results give promise for realizing Floquet topological insulators.

  3. Complete mitochondrial genome of freshwater shark Wallago attu (Bloch & Schneider) from Indus River Sindh, Pakistan.

    Science.gov (United States)

    Laghari, Muhammad Younis; Lashari, Punhal; Xu, Peng; Zhao, Zixia; Jiang, Li; Narejo, Naeem Tariq; Xin, Baoping; Sun, Xiaowen; Zhang, Yan

    2016-01-01

    Complete mitochondrial genome of fresh water giant catfish, Wallago attu, was isolated by LA PCR (TakaRa LAtaq, Dalian, China); and sequenced by Sanger's method to obtain the complete mitochondrial genome. The complete mitogenome was 15,639 bp in length and contains 13 typical vertebrate protein-coding genes, 2 rRNA and 22 tRNA genes. The whole genome base composition was estimated to be 31.17% A, 28.15% C, 15.55% G and 25.12% T. The complete mitochondrial genome of catfish, W. attu, provides the fundamental tools for genetic breeding.

  4. Effect of three diets in the experimental culture of the common snook (Centropomus undecimalis Bloch, 1792

    Directory of Open Access Journals (Sweden)

    Carmen Polonía R

    2017-09-01

    Full Text Available Objective. To evaluate the effect of three diets on the growth of juvenile common snook (Centropomus undecimalis maintained in freshwater ponds Materials and methods. 108 juvenile of common snook were homogenous and randomly distributed in a pond, divided into 9 corrals of 50 m2. Three diets were applied (D1: commercial food for trout, 45% protein; D2: commercial food for cobia, 50% protein and D3: fresh fish, 17.52% protein. The experimental treatments were assigned in triplicate and diets were supplied in two daily doses. Biometrics were performed every 20 days to assess: weight, size, Length-Weight correlation, Feed Conversion Factor (FCA, Condition Factor (K, Specific Growth Rate (SGR and survival; during 120 days. The results were evaluated with a one-way ANOVA, when differences (p<0.05 were found the means were compared by test Median Mood, otherwise a pos-hoc test was performed (Tukey HSD. Results. Applying the test of Mood Median significant differences were found, showing the highest growth with D2, where values of SGR=0.65±0.09 g/day; FCA=3.76 and K=0.81±0.06. Survival was D1=51.4%, D2=50% and D3=77.8% without inferring statistically among the different diets. Conclusions. The culture of this species in freshwater ponds with commercial food for cobia, is viable in terms of growth and weight gain.

  5. Web-based description of the space radiation environment using the Bethe-Bloch model

    CERN Document Server

    Cazzola, Emanuele; Lapenta, Giovanni

    2015-01-01

    Space weather is a rapidly growing area not only in scientific and engineering applications but also in physics education and in the interest of the public. We focus especially on space radiation and its impact on space exploration. The topic is highly interdisciplinary bringing together fundamental concepts of nuclear physics with aspects of radiation protection and space science. We present a new approach to presenting the topic by developing a web-based tool that combines some of the fundamental concepts from these two fields in a single tool that can be developed in the context of advanced secondary or undergraduate university education. We present DREADCode, an outreach or teaching tool to asses rapidly the current conditions of the radiation field in space. DREADCode uses the available data feeds from a number of ongoing space missions to produce a first order approximation of the dose an astronaut would receive during a mission of exploration in deep space. DREADcode is based on a intuitive GUI interfa...

  6. Mechanical Properties of Laminate Materials: From Surface Waves to Bloch Oscillations

    DEFF Research Database (Denmark)

    Liang, Z.; Willatzen, Morten; Christensen, Johan

    2015-01-01

    We propose hitherto unexplored and fully analytical insights into laminate elastic materials in a true condensed-matter-physics spirit. Pure mechanical surface waves that decay as evanescent waves from the interface are discussed, and we demonstrate how these designer Scholte waves are controlled...... by the geometry as opposed to the material alone. The linear surface wave dispersion is modulated by the crystal filling fraction such that the degree of confinement can be engineered without relying on narrow-band resonances but on effective stiffness moduli. In the same context, we provide a theoretical recipe......, and we demonstrate this numerically for structures with millimeter and centimeter dimensions in the kilohertz to megahertz range. Analytical predictions agree entirely with full wave simulations showing how elastodynamics can mimic quantum-mechanical condensed-matter phenomena....

  7. A teratologia múltipla: Robert Bloch e o seu bestiário

    Directory of Open Access Journals (Sweden)

    Alcebíades Diniz Miguel

    2008-10-01

    Full Text Available Howard Phillips Lovecraft acreditava que os povos, para criarem obras fantásticas de terror sobrenatural, deveriam ter certa “inclinação” para o deslumbramento diante do irracional, afirmando que a França e seu povo, por exemplo, seriam racionais demais para tanto. O escritor cita os judeus no rol dos povos possuidores de uma mitologia, com seus golems, dybbuks e outras criaturas, capaz de inspirar o terror sobrenatural.

  8. Discontinuous Galerkin Approximations for Computing Electromagnetic Bloch Modes in Photonic Crystals

    NARCIS (Netherlands)

    Lu, Zhongjie; Cesmelioglu, A.; van der Vegt, Jacobus J.W.; Xu, Y.

    We analyze discontinuous Galerkin finite element discretizations of the Maxwell equations with periodic coefficients. These equations are used to model the behavior of light in photonic crystals, which are materials containing a spatially periodic variation of the refractive index commensurate with

  9. Histopathology biomarker responses in Asian sea bass, Lates calcarifer (Bloch exposed to copper

    Directory of Open Access Journals (Sweden)

    A. Maharajan

    2016-10-01

    Full Text Available Copper is a trace element necessary for the normal growth and metabolism of living organisms. If exceeds its limit it becomes pollutant and causes pathological effects. Asian sea bass (Lates calcarifer was exposed to sublethal concentrations of copper for 28 days and histopathological alterations were noticed in the gill, liver, muscle and intestine. Epithelial necrosis, hypertrophy, rupture of gill epithelium and haemorrhage at primary lamellae were observed after 7 days of exposure. Lifting of epithelium, oedema and fusion of adjacent secondary lamellae were conspicuous at 28 days of exposure. The experimental liver tissue showed reduction in the size of hepatocytes, vacuolisation, and hypertrophy. The intestine displayed fused microvilli, sloughing of mucus membrane and swollen cells. Muscle bundles with severe oedema and their thickening and separation were more pronounced in sublethal treatment of copper in the muscle. Several histopathological changes observed in various fish organs would serve a useful purpose in evaluating the toxic effects of copper. The present study clearly demonstrated that all the treated body organs exhibited significant damage with response; amongst the body organs the liver is an important target organ for copper toxicity in L. calcarifer and this species could be possibly used as a model organism for toxicity studies.

  10. GROWTH AND EXPLOITATION STATUS (Channa striata Bloch, 1793 IN LUBUK LAMPAM FLOODPLAINS, SOUTH SUMATERA

    Directory of Open Access Journals (Sweden)

    Zulkarnaen Fahmi

    2013-06-01

    Full Text Available Due to the economic importance of C. striata in Lubuk Lampam floodplains (Indonesia, this study is aimed to estimate the biological and population parameters required for proposing a future plan to sustain and manage this valuable fish resource. The growth, mortality and explotation ratio of Channa striata estimated by employing FiSATProgramme are reported. The parameters of Von Bertalanffy growth model of 1,529 sample fishes were estimated as K= 0.36/ year, L” = 72.98 cm and to = -0.52 year. The coefficients of total mortality (Z, natural mortality (M and fishing mortality (F were 1.72, 0.73 and 0.99 year-1 respectively. Relative yield per recruit analysis shows that the presentexploitation rate (E was 0.58. Yield per recruit can be maximized at the exploitation ratio of 0.5 and Lc/Linf values of 0.3. The Yield per recruit and biomass per recruit models indicated that, the fisheries status of C. striata in Lubuk Lampam floodplains exceed the limit reference point (Fmax, thus stock of this species in Lubuk Lampam floodplains is indicated being driving down.Reduction in fishing effort and increase number of selective fishing gears are suggested to sustain the fishery of Channa striata in Lubuk Lampam floodplains.

  11. Pisces, Ophidiiformes, Ophidiidae, Brotula barbata (Bloch & Schneider, 1801: First record off Ceará,northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Paiva, C. C.

    2010-01-01

    Full Text Available Brotula barbata is recorded for the first time from Ceará, northeastern Brazil. The species was previouslyknown in the western Atlantic from North Carolina to southeastern Brazil, but there are some gaps between these regions.A single specimen was collected from a traditional line fishing fleet operating in the Mucuripe Sea, Ceará, during August2007. We noticed a meristic difference between the specimen examined and the information from the literature. Howeverthis difference did not make the identification difficult. The new record of B. barbata fills geographic distribution gaps ofthis species in the western Atlantic.

  12. Caloric densities of ingested food of Etroplus suratensis (Bloch) grown in a culture pond

    Digital Repository Service at National Institute of Oceanography (India)

    Sumitra-Vijayaraghavan; Krishnakumari, L.; Dhawan, R.M.; Royan, J.P.

    Analyses of stomach contents of E.suratensis indicated that it is principally a phytoplankton-detritus feeder. Biochemical analyses of the ingested food showed that of the total consumed food, 44% was contributed by ash content, while 56...

  13. Evaluacion del contenido de aminoacidos en guabina , bloch 1794, capturadas en el embalse hipereutrofico de Suata

    National Research Council Canada - National Science Library

    Acuna, Julymar; Gonzalez, Ernesto Jose; de los Angeles Alvarez, Maria; Penaherrera, Carlos; Barrero, Marinela

    2011-01-01

    ... esenciales para humanos, tales como, lisina, metionina, cisteina, treonina y triptofano [23, 29, 32]. Los productos pesqueros son particularmente buena fuente de lisina, que se encuentra en muy bajas proporciones en los cereales, el producto alimenticio mas importante en el mundo. Una reduccion en el suministro de lisina en la dieta puede conducir a p...

  14. Effects of stocking density on growth and production performance of indigenous stinging catfish, Heteropneustes fossilis (Bloch

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    A.H.M. Kohinoor

    2012-12-01

    Full Text Available An on-farm experiment was undertaken in nine earthen ponds to evaluate the growth and production potentials of stinging catfish shing, Heteropneustes fossilis for the period of six months from March to August 2010. Three stocking densities such as 1,25,000 (T1, 1,87,500 (T2 and 2,50,000 ha-1 (T3 were tested with three replications each. Fish were fed with commercial pelleted feed containing 35% crude protein. After six months rearing, the mean harvesting weights of shing were 69.42±6.20, 58.74±3.85 and 49.50±4.52g in T1, T2 and T3, respectively. Significant (P<0.05 highest mean harvesting weight was found in T1. The best survival was found in T1 (87% among the treatments. The calculated mean production of shing (H. fossilis in three treatments such as T1, T2 and T3 were 7549±52, 9031±71 and 8786±60 kg ha-1, respectively, which were significantly different (p<0.05 from each other.

  15. Ontogeny of the digestive tract in butter catfish Ompok bimaculatus (Bloch) larvae.

    Science.gov (United States)

    Pradhan, P K; Jena, J K; Mitra, G; Sood, N; Gisbert, E

    2012-12-01

    The ontogeny of the digestive tract was studied histologically in butter catfish Ompok bimaculatus from hatching to 30 days post-hatching (dph). At hatching, the digestive tract of butter catfish consisted of a straight tube with a smooth lumen dorsally attached to the yolk sac. Between 1 and 2 dph, the mouth opened, oral valves were visible and canine-like teeth and taste buds were detected. During this period, intestine was differentiated into the anterior and posterior intestine, and the digestive accessory glands were also developed. Exogenous feeding started at 2 dph, and there was a 2-day mixed endogenous-exogenous feeding period. Most of the yolk sac reserves were consumed between 2 and 3 dph, and by 5 dph, the yolk sac was completely depleted and no longer visible in histological sections. Between 3 and 4 dph, several vacuoles (neutral lipids) were observed in the intestine and also in hepatocytes, indicating a functional absorption of nutrients from food. At 8 dph, differentiation of gastric glands was noticed, and by 9-11 dph, there were abundant gastric tubular glands arranged along numerous longitudinal folds. During the same period, pyloric sphincter appeared as an epithelial fold that separated the stomach from the anterior intestine. From 12 dph to the end of the study at 30 dph, no noticeable histological modifications were observed. The development of gastric glands is considered as the last major events in digestive tract development and their presence designates the end of larval period and the onset of the juvenile period. Hence, it is suggested that, butter catfish larvae have a morphologically complete digestive tract by 12 dph. These findings on the development of the digestive system in butter catfish may lead to a better understanding of the ontogeny and would be useful to improve the larval rearing techniques of this promising catfish species for freshwater aquaculture diversification.

  16. Near-field imaging of light propagation in photonic crystal waveguides: Explicit role of Bloch harmonics

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Volkov, V.S.; Søndergaard, Thomas

    2002-01-01

    We employ a collection scanning near-field optical microscope (SNOM) to image the propagation of light at telecommunication wavelengths along straight and bent regions of silicon-on-insulator photonic crystal waveguides (PCWs) formed by removing a single row of holes in the triangular 410-nm...... PCW bends, bend loss is evaluated and found to noticeably increase with the increase of the light wavelength from similar to1 dB at 1520 nm to similar to6 dB at 1570 nm. We analyze light intensity variations along PCWs measured with the SNOM at different distances from the sample surface. Considering...

  17. A comparison of adrenergic stress responses in three tropical teleosts exposed to acute hypoxia.

    Science.gov (United States)

    Perry, S F; Reid, S G; Gilmour, K M; Boijink, C L; Lopes, J M; Milsom, W K; Rantin, F T

    2004-07-01

    Experiments were performed to assess the afferent and efferent limbs of the hypoxia-mediated humoral adrenergic stress response in selected hypoxia-tolerant tropical fishes that routinely experience environmental O(2) depletion. Plasma catecholamine (Cat) levels and blood respiratory status were measured during acute aquatic hypoxia [water Po(2) (Pw(O(2))) = 10-60 mmHg] in three teleost species, the obligate water breathers Hoplias malabaricus (traira) and Piaractus mesopotamicus (pacu) and the facultative air breather Hoplerythrinus unitaeniatus (jeju). Traira displayed a significant increase in plasma Cat levels (from 1.3 +/- 0.4 to 23.3 +/- 15.1 nmol/l) at Pw(O(2)) levels below 20 mmHg, whereas circulating Cat levels were unaltered in pacu at all levels of hypoxia. In jeju denied access to air, plasma Cat levels were increased markedly to a maximum mean value of 53.6 +/- 19.1 nmol/l as Pw(O(2)) was lowered below 40 mmHg. In traira and jeju, Cat release into the circulation occurred at abrupt thresholds corresponding to arterial Po(2) (Pa(O(2))) values of approximately 8.5-12.5 mmHg. A comparison of in vivo blood O(2) equilibration curves revealed low and similar P(50) values (i.e., Pa(O(2)) at 50% Hb-O(2) saturation) among the three species (7.7-11.3 mmHg). Thus Cat release in traira and jeju occurred as blood O(2) concentration was reduced to approximately 50-60% of the normoxic value. Intravascular injections of nicotine (600 nmol/kg) elicited pronounced increases in plasma Cat levels in traira and jeju but not in pacu. Thus the lack of Cat release during hypoxia in pacu may reflect an inoperative or absent humoral adrenergic stress response in this species. When allowed access to air, jeju did not release Cats into the circulation at any level of aquatic hypoxia. The likeliest explanation for the absence of Cat release in these fish was that air breathing, initiated by aquatic hypoxia, prevented Pa(O(2)) values from falling to the critical threshold required

  18. RÉGIMEN ALIMENTARIO DE SIETE ESPECIES ÍCTICAS EN EL EMBALSE DE LA HIDROELÉCTRICA URRÁ (CÓRDOBA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    V.J. Atencio-García

    2005-12-01

    Full Text Available El objeto del estudio fue evaluar el régimen alimentario de siete especies de peces que se han establecidoen el embalse de la Hidroeléctrica Urrá (HU. Se analizaron 453 estómagos, distribuidos así: 115 deperico (Tracheolypterus badeli cf, 111 de cacucho (Panaque gibbosus, 108 de yalúa (Cyphocharaxmagdalenae, 89 de mojarra amarilla (Caquetaia kraussii , 11 de moncholo (Hoplias malabaricus, 10 debarbul ( Pimelodus clarias y 9 de doncella ( Ageneoisus pardales . Los contenidos estomacales se evaluaronmediante frecuencia de ocurrencia (FO, frecuencia numérica (FN y el método gravimétrico (G. Sedeterminó la importancia de cada presa mediante el índice de categorización de presa (ICP y lasuperposición de dietas se analizó mediante el Índice de Morosita (IM. La distribución porcentual de loscontenidos estomacales de la yalúa mostró que el 95.5% correspondió al ítem detritus y el restante 4.5%a microlagas (Clorofitas y Bacillariofitas y protozoarios/rotíferos. La dieta del cacucho la conformaron enun 70.9% microalgas (Cianofitas, Clorofitas y Bacilariofitas y protozoarios/rotíferos y el restante 29.1%correspondieron al ítem detritus. Barbul (FO = 50%, FN = 46.2% y perico se alimentaron principalmentede insectos (FO = 73.9%, FN = 86.4%. La mojarra amarilla (FO = 87.1%, FN = 83.3%, doncella(FO = 92.3%, FN = 92.0% y moncholo (FO = 90.9%, FN = 90.9% prefieren peces como cachanita(Roeboides dayi y sardinas ( Astianax sp. Los resultados sugieren que yalúa es detritívoro iliófago, cacuchoes detritívoro, perico y barbul son carnívoros insectívoros y doncella, moncholo y mojarra amarilla soncarnívoros piscívoros.

  19. Infección por Gnathostoma (Spirurida: Gnathostomatidae en Hoplias microlepis: prevalencia, correlación con la talla del pez, huéspedes e implicaciones para salud pública en Ecuador

    Directory of Open Access Journals (Sweden)

    Juan José Alava

    2009-12-01

    Conclusiones. La gnathostomiasis sigue siendo prevalente en la zona costera de Ecuador y el agente patógeno es aún encontrado en el huésped intermediario. Diversos mamíferos neotropicales estarían actuando como huésped reservorio definitivo en el ciclo biológico de Gnathostoma en Ecuador.

  20. The distribution and abundance of wetland ichthyofauna,and exploitation of the fisheries in the Godineau Swamp,Trinidad -Case study

    Directory of Open Access Journals (Sweden)

    Himawatee Ramsundar

    2005-05-01

    Full Text Available The Godineau (South OropucheSwamp (3171 haon the southwestern coast of Trinidad (10 º13- 15 ’N,61 º30-32 ’Wis heavily impacted by anthropogenic activities including fishing,oil exploration, drainage manipulation and wetland clearance.To reduce the negative effects of these activities and to manage the swamp more sustainably,more quantitative information is needed on the ecology of the wetland and the activities that occur within it.This study focuses on the distribution of the fish resources and exploited fisheries as a basis for more informed management directives. Sampling was conducted during 2002,in April-May (for dry seasonand July-September (for wet season sampling.Ichthyofauna was sampled both day and night using trammel nets and a push seine.Fishing activities were assessed using a questionnaire and informal discussions with fishers.The wetland supports over 29 species of fish distributed over the freshwater,estuarine and saline zones (n=1454. Species distribution is seasonal,with evidence of the wetland being used as a spawning ground. Species richness and species diversity (Shannon-Weiner Indexfor the wetland ranged over 2-11 and 0.162-0.967,respectively, in the dry season and 2-7 and 0.036-0.903,respectively,in the wet season.Communities inhabiting the saline and estuarine zones of the wetland were dominated by a single species,Hexanematichthys bonillai .Percent Similarity Indices were 41.8%for freshwater, 72.7%for estuarine and 79.8%for estuarine-saline communities. The commercial species accounted for 18%of total catch sampled and consisted of Centropomus undecimalis, Megalops atlanticus ,Hoplosternum littorale ,Hoplias malabaricus ,Ophioscion punctatissimus and Macrodon ancyclodon .Full-time and part-time fishers,including recreational fishers,accounted for 14.3%and 85.7%, respectively of all fishers surveyed (n=56.A conservative estimate of the revenue earned directly at point of sale for fish and shellfish,is approximately

  1. Feeding ecology of stream-dwelling fishes from a coastal stream in the Southeast of Brazil

    Directory of Open Access Journals (Sweden)

    Rosana Mazzoni

    2007-07-01

    Full Text Available The relationship between ontogenetic variation of intestine length and feeding habits of five stream-dwelling fish species from the Ubatiba River were investigated. Analysed data were based on two size categories (juveniles and adults and two food categories (animal and vegetal. Diet composition of each size category revealed that Astyanax janeiroensis and Geophagus brasiliensis changed food preference throughout ontogeny and switched from omnivorous/carnivorous to omnivorous/herbivorous and from omnivorous/carnivorous to omnivorous, respectively. These changes were followed by ontogenetic changes in the Intestinal Coefficient (IC. No ontogenetic differences were registered for IC and food categories consumed by Hoplias malabaricus but significant differences in the size of consumed preys as well as positive correlation between fish size (predator and prey size was observed. Food items (within animal category consumed by the adult Pimelodella lateristriga were mainly based on allochthonous arthropods whereas juvenile individuals fed with the same intensity on allochthonous and autochthonous arthropods; both juveniles and adult individuals of Mimagoniates microlepis were mainly allochthonous feeders. Mean IC values of Pimelodella lateristriga and Mimagoniates microlepis did not change along body growth. Although changes in food category consumption were not common among all the studied species, changes in the resource exploitation strategy was a rule among them, except for Mimagoniates microlepis.Foi investigada a relação entre as variações ontogenéticas do comprimento do intestino e os hábitos alimentares de cinco espécies de peixes do rio Ubatiba, RJ. Os dados analisados foram baseados em duas categorias de tamanho (jovens e adultos de cada espécie e duas categorias de alimento (animal e vegetal. A composição da dieta de cada categoria de tamanho revelou que Astyanax janeiroensis e Geophagus brasiliensis mudaram a prefer

  2. New combinationsand a new name for Sri Lankan Coleus species (Labiatae)

    NARCIS (Netherlands)

    Willemse, R.H.

    1979-01-01

    Seven Coleus species, of which six occur in Sri Lanka and one in East Africa, are transferred to Plectranthus. The following new names are published: P. grandis (Cramer) Willemse, P. inflatus (Benth.) Willemse, P. malabaricus ( (Benth.) Willemse, var. malabaricus and var. leptostachys (Benth.)

  3. Poecilancistrium caryophyllum (Diesing, 1850 (Cestoda, Trypanorhyncha, parasito de Macrodon ancylodon (Bloch & Schneider, 1801 do litoral Norte do Brasil Poecilancistrium caryophyllum (Diesing, 1850 (Cestoda, Trypanorhyncha, parasite of Macrodon ancylodon (Bloch & Schneider, 1801 from the Northern littoral of Brazil

    Directory of Open Access Journals (Sweden)

    Silvio Abner Lameira de Oliveira

    2009-12-01

    Full Text Available O objetivo desta pesquisa foi registrar a presença de cestoides Trypanorhyncha, suas prevalências e intensidades de infecção, na musculatura e serosa abdominal parietal de 50 exemplares de Macrodon ancylodon, capturados no litoral Norte do Brasil e beneficiados em Belém, Estado do Pará, durante o período de junho de 2004 a janeiro de 2005. A musculatura e serosa abdominal dos peixes foram examinadas em mesa de inspeção candling table após o filetamento das amostras. Oito peixes encontravam-se parasitados por plerocercoides da espécie Poecilancistrium caryophyllum, com prevalência de 16% e intensidade média de infecção de um plerocerco por peixe, tendo como único sítio de infecção a musculatura. A espécie Poecilancistrium caryophyllum é, pela primeira vez, registrada para M. ancylodon.The aim of this research was to report the presence of Trypanorhyncha cestodes, their prevalence and mean intensity in the muscles musculature and abdominal serose in commercial fish processed in Belém, Pará State. Fifty specimens of M. ancylodon were captured in the North Coast of Brazil. The musculature and adjacent abdominal serose of fish were analized in a "candling table" after filleted. Eight specimens were parasitized by plerocercoids of Poecilancistrium caryophyllum, with a prevalence of 16% and mean intensity of infection of one plerocercus per fish, varying from the unique site of infection was the musculature. The species P. caryophyllum is reported by the first time on M. ancylodon.

  4. Assessment of pollution of river Ganges by tannery effluents using genotoxicity biomarkers in murrel fish, Channa punctatus (Bloch).

    Science.gov (United States)

    Nagpure, N S; Srivastava, Rashmi; Kumar, Ravindra; Dabas, Anurag; Kushwaha, Basdeo; Kumar, Pavan

    2015-07-01

    River pollution due to rapid industrialization and anthropogenic activities adversely affects the aquatic organisms, especially fish. Here, we assessed the genotoxicity, mutagenicity and bioaccumulative aspects of tannery effluents in freshwater murrel, Channa punctatus, an inhabitant of river Ganges. Test specimens were collected from three different polluted sites of the river within and nearby Kanpur area during different seasons and blood samples of these specimens were processed for comet assay and micronucleus test as genotoxicity biomarkers. A significantly (P industry) above the maximum permissible limits as prescribed by World Health Organization (WHO). The findings of the present analysis indicated contamination of river Ganges with tannery effluents which induce genotoxicity in fish with seasonal variation.

  5. Florence Hulak. Sociétes et mentalités. La science historique de Marc Bloch.

    Directory of Open Access Journals (Sweden)

    Renán Silva

    2016-01-01

    Full Text Available Hay obras de análisis histórico (y esta lo es, aunque en el campo de la epistemología de la historia que pueden resumirse fácilmente, bien sea por su contenido renovador, bien sea por sus equívocos y errores, o bien sea por su propio carácter rutinario (una más entre una cadena de libros previsibles en su enfoque y en sus resultados. Hay otras obras que solicitan, de quien se ocupa de ellas y trata de presentarlas ante una comunidad de lectores alejada de su lugar de producción y de recepción iniciales del texto, tan solo un sobrevuelo inicial, una mención de sus temas y propósitos centrales, un énfasis repetido sobre su significado e importancia, para animar a los lectores a que se interesen en el debate planteado por el libro de referencia y, sobre todo, a que no se deje pasar de largo una oportunidad de discusión que puede servir para refinar el planteamiento de problemas de los que se habla de manera repetida con actitud poco reflexiva, repetitiva y rutinaria. Creo que este es el caso del libro reciente de Florence Hulak, Sociétés et mentalités que queremos presentar aquí, a través de una reseña centrada simplemente en sus grandes temas, dejando para otros momentos el debate preciso (textos en mano y con multiplicadas referencias, ejemplos, contra ejemplos y argumentaciones sobre puntos concretos de los planteamientos de la autora.

  6. Accumulation effects in modulation spectroscopy with high-repetition-rate pulses: Recursive solution of optical Bloch equations

    Science.gov (United States)

    Osipov, Vladimir Al.; Pullerits, Tõnu

    2017-10-01

    Application of the phase-modulated pulsed light for advance spectroscopic measurements is the area of growing interest. The phase modulation of the light causes modulation of the signal. Separation of the spectral components of the modulations allows to distinguish the contributions of various interaction pathways. The lasers with high repetition rate used in such experiments can lead to appearance of the accumulation effects, which become especially pronounced in systems with long-living excited states. Recently it was shown that such accumulation effects can be used to evaluate parameters of the dynamical processes in the material. In this work we demonstrate that the accumulation effects are also important in the quantum characteristics measurements provided by modulation spectroscopy. In particular, we consider a model of quantum two-level system driven by a train of phase-modulated light pulses, organized in analogy with the two-dimensional spectroscopy experiments. We evaluate the harmonics' amplitudes in the fluorescent signal and calculate corrections appearing from the accumulation effects. We show that the corrections can be significant and have to be taken into account at analysis of experimental data.

  7. Ammonium sulphate induced stress related alterations in the respiratory epithelium of the airbreathing organ of the catfish Heteropneustes fossilis (Bloch)

    Digital Repository Service at National Institute of Oceanography (India)

    Paul, V.I.; Banerjee, T.K.

    In this paper, histopathological changes in the inner lining of the accessory respiratory organ of Heteropneustes fossilis following exposure to sublethal concentration (0.2 gl sup(-1)) of ammonium sulphate (3 mg l sup(-1) total ammonia-N) has been...

  8. Spatial morphometric plasticity of spirlin Alburnoides bipunctatus (Bloch, 1782 phenotype from the Nišava River, Serbia, Danube basin

    Directory of Open Access Journals (Sweden)

    Živković, D.

    2011-09-01

    Full Text Available Variation of 22 morphometric and 4 meristic characters of the species Alburnoides bipuuctatus from Nišava River were analyzed. Specimens were collected from four sampling stations along the putative mesohabitat gradient of river influence and were grouped into the categories with similar total length. Morphometric characters varied immensely between different mesohabitats outlining morphometric plasticity. Among several morphometry features that were influenced by different mesohabitats the most observable differences were noted for: postocular distance, anal fin height, minimal body height and preanal length. Regarding the meristic features, number of soft rays in the anal fin did varied significantly among sampling stations while fourth hard ray in the anal fin for this species was reported for the first time ever. Pharyngeal teeth formula of spirlin also showed variability across different mesohabitats. In conclusion, it appears that spirlin express a big morphological plasticity in relation to spatial and mesohabitat distribution and there is a possibility that spirlin from Nišava River is a complex of neospecies in formation/morphotypes/ecotypes rather than a single population.

  9. A new distributional record of alligator pipefish, Syngnathoides biaculeatus (Bloch, 1785) along Goa, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sanaye, S.V.; Rivonker, C.U.; Ansari, Z.A.; Sreepada, R.A.

    re´gulations hormonales de l’incubation chez un Verte`bre male: recherches sur la reproduction de l’Hippocampe. PhD thesis, l’Universite´ de Bordeaux, France. (1967). 36 Tipton K & Bell S S., Foraging patterns of two syngnathid fishes: importance... of harpacticoid copepods. Mar Ecol Prog Ser., 47 (1988) 31–43. 37 Do H H, Truong S K & Ho T H., Feeding behaviour and food of seahorses in Vietnam. In Proceedings of the 3rd International Conference on the Marine Biology of the South China Sea edited...

  10. Toxicity of puffer fish: two species (Lagocephalus laevigatus, linaeus 1766 and Sphoeroides spengleri, Bloch 1785 from the Southeastern Brazilian coast

    Directory of Open Access Journals (Sweden)

    J. S. Oliveira

    2003-01-01

    Full Text Available In Brazil, where puffer fish are considered poisonous, there are few documented cases on human consumption and consequent poisoning. In this study, toxicity of two puffer fish species from the Brazilian coast was examined. Specimens of Sphoeroides spengleri and Lagocephalus laevigatus were caught in São Sebastião Channel (North coast of São Paulo State, Brazil between January 1996 and May 1997. Acidic ethanol extracts from muscle and skin plus viscera were tested for mice acute toxicity using the standard method of Kawabata. Polar extracts of S. spengleri showed high toxicity up to 946 MU/g. Extracts from L. laevigatus showed very low levels of toxicity, never exceeding 1.7 MU/g. All extracts from both species blocked amielinic nerve fiber evoked impulses of crustacean legs; this effect reverted on washing similar to the standard tetrodotoxin TTX. The aqueous extract solutions were partially purified using an ionic exchange column (Amberlit GC-50 followed by treatment with activated charcoal (Norit-A. The presence of TTX and their analogs in the semi-purified extracts were confirmed by HPLC and mass spectrometry (MALDI-TOF.

  11. Rohdella amazonica n. sp. (Aspidogastrea: Aspidogastridae) from the Amazoninan banded puffer fish Colomesus psittacus (Bloch & Schneider, 1801).

    Science.gov (United States)

    Giese, E G; Silva, M V O; Videira, M N; Furtado, A P; Matos, E R; Gonçalves, E C; Melo, F T V; Santos, J N

    2015-05-01

    Aspidogastreans are commonly found infecting freshwater and marine molluscs, teleosts fishes and freshwater turtles. The subclass comprises four families - Rugogastridae Schell 1973, Stichocotylidae Faust & Tang 1936, Multicalycidae Gibson & Chinabut 1984 and Aspidogastridae Poche 1907 - and it is characterized by the presence of a ventral adhesive disc divided into rows of alveoli. In the current work, using light and scanning electron microscopy and molecular approaches, a new species of Aspidogastridae of the genus Rohdella Gibson & Chinabut, 1984, is described as a parasite of Colomesus psittacus in Brazil. The new taxon is distinguishable by the presence of oesophageal glands, teguments covered by ciliated papillae, and the position and shape of the hermaphroditic duct. The present work describes the third species of the genus Rohdella, thereby adding new morphological and molecular data regarding Aspidogastridae.

  12. Some remarks on the South American Pimelodid catfish usually known by the name of Phractocephalus Hemiliopterus (Bloch & Schneider) (Pimelodidae, Siluriformes)

    NARCIS (Netherlands)

    Boeseman, M.

    1983-01-01

    The present note draws attention to the first substantiated Phractocephalus record from Surinam, to the customary incorrect spellings of the specific name since Cuvier, 1829 and to an unexpected ontogenetic change in the striking colour pattern of this species.

  13. Quantum Analysis of a Microcavity-Tuned Bloch Oscillator for Tunable Spontaneous Emission and Absorption of Terahertz Radiation

    Science.gov (United States)

    2007-06-20

    interface impurities with randomly distributed interface roughness, it can be shown7 that fkk ′ (t) is expressed as fkk ′ (t) = VKK′ e − i h̄ [η(K)−η(K...only the term with ly = 1 need be retained in Eqs. (10) and (11). Then, in utilizing fkk ′ (t) from Eq. (9) in Eq. (6), and anticipating the ensemble...average over the randomly distributed interface roughness coordinates, which renders the ensemble average over the fkk ′ (t) term on the right-hand

  14. A preliminary survey on parasitic occurrence in indigenous climbing perch, Anabas testudineus (Bloch, 1972 from West Bengal state of India

    Directory of Open Access Journals (Sweden)

    Basudev Mandal

    2016-08-01

    Full Text Available Objective: To describe the parasitic infestations of Anabas testudineus (A. testudineus collected from three different fish producing districts of West Bengal state in India. Methods: A total number of 75 specimens of A. testudineus were collected from different floodplain areas of West Bengal, India. These specimens were examined for parasites using established techniques after measuring basic morphometric parameters. Results: A total 165 individual of 20 parasites (13 ectoparasites and 7 endoparasites belonging to 7 phyla were recorded from 64 infected A. testudineus. Among the observed parasites, 8 were protozoan including 3 ciliates; 2 monogenic trematodes, 2 strigeidid trematodes, 1 nematode, 3 crustaceans, 3 myxozoans and 1 echinorhynchus acanthocephalan parasites. The quantitative abundance of parasites were highest in gill (37% followed by body outer layer (35% and intestine (28%. District wise quantitative count of parasites in different investigated organ from A. testudineus revealed that North 24 Parganas is highly infected followed by West Midnapore and East Midnapore. The highest prevalence (% and mean abundance of parasitic occurrence was observed in North 24 Parganas followed by West Midnapore and East Midnapore. The highest mean intensity was found at West Midnapore followed by North 24 Parganas and East Midnapore. Conclusions: Especially West Bengal state of India, inland culture and capture fishery mainly rural based and operated by poor farmers. Developing right kind of interventions and management practice can prevent adverse impact of diseases and assist poor farmers for sustainable production.

  15. Growth and survival of a diallel cross for five strains of climbing perch (Anabas testudineus Bloch, 1792 in Thailand

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    Nitikorn Piwpong

    2016-09-01

    Full Text Available A complete diallel cross experiment was conducted with five strains of climbing perch (Anabas testudineus representing three wild populations collected from main river basins in Thailand and two farm populations in southern Thailand. Growth performance was recorded from 794 individually tagged progeny of the 24 different strain combinations after a grow-out period of about 130 d in an earthen pond. Least squares means of body weight at harvest and absolute growth rates were computed for each strain combination. The Chumphon strain showed the highest growth performance (81.1 ± 1.1 g. The Surat Thani × Chumphon (the first strain represents the sire showed the highest survival (65.4± 25.50% among the purebreds and the crossbreds. The domesticated gene pool had much better growth in aquaculture than the wild gene pool. The correlation between the least squares means of body weight and the survival rates in the 24 strain combinations was 0.51 (p < 0.05. The mean heterosis of all crossbreds across traits was negative (−10.2± 22.7%. Heterosis appeared to decrease when different gene pools were crossed. This suggests that there may be outbreeding depression. The advantage of crossbred performance was clearly not shown in the study.

  16. Chronic exposure to sublethal hexavalent chromium affects organ histopathology and serum cortisol profile of a teleost, Channa punctatus (Bloch)

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Ashish K. [Department of Zoology, University of Allahabad, Allahabad-211002 (India); Mohanty, Banalata, E-mail: drbana_mohanty@rediffmail.com [Department of Zoology, University of Allahabad, Allahabad-211002 (India)

    2009-09-01

    Effects of chronic exposures (one and two months) to sublethal doses of hexavalent chromium (2 and 4 mg/L potassium dichromate) on organ histopathology and serum cortisol profile were investigated and their overall impact on growth and behavior of a teleost fish, Channa punctatus was elucidated. Histopathological lesions were distinct in the vital organs gill, kidney and liver. The gill lamellae became lifted, fused, and showed oedema. Hyperplasia and hypertrophy of lamellar epithelial cells were distinct with desquamation. Hypertrophy of epithelial cells of renal tubules and reduction in tubular lumens were observed in the trunk kidney. The atrophy of the head kidney interrenal cells and decreased serum cortisol level indicated exhaustion of interrenal activity. Hepatocyte vacuolization and shrinkage, nuclear pyknosis and increase of sinusoidal spaces were observed in the liver. Abnormal behavioral patterns and reduced growth rate were also noticed in the exposed fish. The chronic hexavalent chromium exposure thus by affecting histopathology of gill, kidney (including interrenal tissue) and liver could impair the vital functions of respiration, excretion, metabolic regulation and maintenance of stress homeostasis which in the long-run may pose serious threat to fish health and affect their population.

  17. DOE Zero Energy Ready Home Case Study: Amerisips Homes — Miller-Bloch Residence, Johns Island, SC

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-09-01

    For this DOE Zero Energy Ready Home that won a Custom Builder award in the 2014 Housing Innovation Awards, the builder uses structural insulated panels to construct the entire building shell, including the roof, walls, and floor of the home.

  18. Age, growth and mortality of dog snapper Lutjanus jocu (Bloch & Schneider, 1801 in the northeast coast of Brazil

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    Sérgio de Magalhães Rezende

    2004-06-01

    Full Text Available The age and growth of Lutjanus jocu was assessed through readings of growth marks in sagitta otoliths. From August 1996 to March 2000, fish were sampled (n=3.539 in the northeast portion of the Brazilian Exclusive Economic Zone. Sagitta otoliths were extracted from a sub sample of 216 individuals caught around the oceanic bank Sirius (03°59' s; 35°59' w and over continental shelf from Ceará (05°03's; 36°02'w to Bahía States (09°01's; 35°12'w. Opaque bands, presumed to be annual, were observed on whole (n= 210 and sectioned (n= 197 otoliths, showing ages from 0 to 20 and from 0 to 25 years respectively. The von Bertalanffy growth model was fit to length-at-age data resulting in the values of Li= 77.22 cm, K= 0.110 and t0= -3.73. Incremental widths from the first to twentieth opaque band on sectioned otoliths (n = 39 were used on back calculation of length-at-ages and the estimated values were Li= 71,20 cm, K= 0.112 e t0= -4.32. Otolith reading from sections is a reliable technique for aging L. jocu, which presented medium to high longevity and slow growth. Total mortality (Z estimated by the catch curve was 0.134 corresponding to an annual survival rate of 87.5%. The natural mortality (M estimated by the Ault et al. (1998 methodology was 0.12 for 25 years of longevity.Idade e crescimento do Lutjanus jocu foi determinada através da leitura de marcas de aposição em otólitos sagittae. 216 indivíduos, capturados no entorno da montanha oceânica Sirius e na plataforma continental do Ceará (05°03's; 36°02'w até a Bahia (09°01's; 35°12'w tiveram seus otólitos extraídos. Marcas opacas que provavelmente formam-se anualmente foram observadas em otólitos inteiros (n=210 e em otólitos seccionados (n=197 apresentando peixes com idades entre 0 a 20 e 25 anos respectivamente. O modelo de crescimento de Bertalanffy ajustado por métodos não lineares dos mínimos quadrados aos dados de idade e comprimento resultou em valores de Li= 77,22 cm, K= 0,110 and t0= -3,73. Medidas incrementais da 1ª a 20ª marca opaca em otólitos seccionados (n=39 foram usadas para retrocalcular os comprimentos e as respectivas idades resultando em valores de Li= 71,20 cm, K= 0,112 e t0= -4,32. Leitura de otólitos seccionados de L. jocu é uma técnica confiável para a determinação da idade e crescimento desta espécie, que apresentou longevidade de média a alta com crescimento lento. A taxa de mortalidade total (Z estimada através da curva de captura foi 0,134 correspondendo a 87,5% de sobrevivência anual. A mortalidade natural (M calculada pelo método de Ault et al. (1998 foi 0,12 para uma longevidade de 25 anos.

  19. Prism coupling method to excite and analyze Floquet-Bloch modes in linear and nonlinear waveguide arrays.

    Science.gov (United States)

    Rüter, Christian E; Wisniewski, J; Kip, Detlef

    2006-09-15

    We demonstrate an experimental method for the direct measurement of band structures of one-dimensional periodic optical media. With the help of a prism coupler that is used in a retroreflective scheme, the allowed bands of a waveguide array in lithium niobate are determined and the results are compared with numerical calculations. Furthermore, we demonstrate the suitability of this method to measure propagation constants of extended nonlinear modes inside the forbidden gap.

  20. JENIS PAKAN ALAMI LARVA IKAN BETOK (Anabas testudineus Bloch DI PERAIRAN RAWA MONOTON DANAU BANGKAU, KALIMANTAN SELATAN

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    Rukmini Rukmini

    2016-03-01

    Full Text Available Usaha pembenihan ikan merupakan alternatif pemecahan masalah untuk mengatasi kesenjangan antara ketersediaan dan kebutuhan benih dalam budidaya ikan. Keberhasilan usaha pembesaran ikan betok dibatasi oleh tingkat kelangsungan hidup larva bagi pertumbuhan dan jenis pakan alami larva ikan di habitatnya. Tujuan penelitian ini adalah untuk mengetahui jenis dan kelimpahan pakan alami yang dikonsumsi larva ikan betok di perairan rawa monoton Danau Bangkau Kalimantan Selatan. Penelitian dilaksanakan pada bulan Desember 2011-Januari 2012. Pengambilan sampel pakan dan larva dilakukan pada dua tempat yang berbeda pada kedalaman 30 cm. Hasil penelitian menunjukkan jenis plankton yang dikonsumsi oleh larva ikan betok berubah sesuai dengan ukuran bukaan mulut ikan dan kelimpahan plankton di perairan. Jenis plakton dominan yang dimakan oleh larva betok yaitu Mougeotia sp. 265 sel/L diikuti oleh Coconeis sp. 246 sel/L, Keratella sp. 174 sel/L, Chlorococcum sp. 110 sel/L, Brachionus sp. 98 sel/L, dan Navicula sp. 47 sel/L. Jenis plakton dominan yang dimakan berubah sesuai dengan umur larva.   Business seeding fish an alternative problem-solving to overcome the gap between availability and needs seeds. The success of the business of enlargement climbing fish bounded by the degree of continuity larvæ live for growth and a kind of natural fish larvae feed on their habitat. The purpose of this research was to know the type of plankton that were consumed by climbing perch fish larvae in the waters of the monotonous swamp of Danau Bangkau. The research was conducted from December, 2011- January, 2012. The sample feed and larvæ carried on two different places at the depth of 30 cm. The result showed plankton species consumed by climbing fish larvae change according to size openings mouth fish and abundance plankton in waters. A kind of plankton dominant which are eaten by the climbing larvæ  namely Mougeotia sp. 265 cells/L followed by Coconeis sp. 246 cells/L, Keratella sp. 174 cells/L, Chlorococcum sp. 110 cells/L, Brachionus sp. 98 cells/L, and Navicula sp. 47 cells/L. A kind of plankton dominant eaten changed in accordance with the age of larvæ.

  1. Cytochrome b gene reveals panmixia among Japanese Threadfin Bream, Nemipterus japonicus (Bloch, 1791) populations along the coasts of Peninsular Malaysia and provides evidence of a cryptic species.

    Science.gov (United States)

    Lim, Hong-Chiun; Ahmad, Abu Talib; Nuruddin, Ahmad Adnan; Mohd Nor, Siti Azizah

    2016-01-01

    We evaluated genetic differentiation among ten presumed Japanese threadfin bream, Nemipterus japonicus populations along the coast of Peninsular Malaysia based on the partial sequence of the mitochondrial cytochrome b gene (982 bp). Genetic divergences (Kimura-2 parameter) ranged from 0.5% to 0.8% among nine of the ten populations while these nine populations were 4.4% to 4.6% diverged from the Kuala Besar population located at the Northeast coast. The constructed Neighbour Joining (NJ) phylogenetic trees based on haplotypes showed the Kuala Besar population forming an isolated cluster. The Analysis of Molecular Variance (AMOVA) of the ten populations a priori assigned into four regions, revealed that most of the variation occurred within population with a fairly low but significant level of regional differentiation (FST = 0.07, p 0.05 and FCT = 0.07, p Malaysia were panmictic. However, the Kuala Besar population, although morphologically identical was composed of a genetically discrete taxon from the rest. These findings are important contributions in formulating sustainable fishery management policies for this important fishery in Peninsular Malaysia.

  2. Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch

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    Satish Kumar Srivastava

    2010-08-01

    Full Text Available The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L-1, respectively, in a semi static system with significant difference (p < 0.05 in LC10-90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ~10.600 mg·L-1, 1/8 LC50 = ~5.300 mg·L-1 and 1/10 LC50 = ~4.238 mg·L-1 induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD, catalase (CAT and glutathione reductase (GR responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes.

  3. Female morphology of Philometra hyderabadensis Rasheed, 1963 (Nematoda: Philometridae), a little-known parasite of the catfish Wallago attu Bloch & Schneider in India, as revealed by SEM observations

    Czech Academy of Sciences Publication Activity Database

    Moravec, František; Chavan, S. P.

    2012-01-01

    Roč. 83, č. 2 (2012), s. 117-122 ISSN 0165-5752 R&D Projects: GA ČR GBP505/12/G112 Institutional research plan: CEZ:AV0Z60220518 Keywords : Philometra * Wallago * India Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.260, year: 2012

  4. Biologia pesqueira das raias Dasyatis guttata (bloch & schneider, 1801) e Dasyatis Americana Hildebrand & Schroeder, 1928, no Estado do CearÃ

    OpenAIRE

    Guelson Batista da Silva

    2005-01-01

    As raias das espÃcies Dasyatis guttata e Dasyatis americana constituem importantes recursos pesqueiros no Estado do CearÃ. O objetivo geral desta DissertaÃÃo à estudar a biologia pesqueira dessas espÃcies com vistas ao uso das informaÃÃes como constituintes de eventuais medidas de gerenciamento de sua exploraÃÃo. Dentro desse contexto geral, foram abordados aspectos relacionados com a biometria e suas relaÃÃes morfomÃtricas, dieta alimentar e reproduÃÃo, quanto ao comprimento mÃdio na 1 matu...

  5. Molecular and cytogenetic analyses of cryptic species within the Synbranchus marmoratus Bloch, 1795 (Synbranchiformes: Synbranchidae grouping: species delimitations, karyotypic evolution and intraspecific diversification

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    Ricardo Utsunomia

    Full Text Available The fish species Synbranchus marmoratushas been reported to exist as a species complex due to high intraspecific karyotypic variability in spite of the difficulty or impossibility to distinguish them using morphological traits alone. The goal of this work was to use cytogenetic and molecular methods to determine the species delimitations and understand the karyoevolution ofS. marmoratususing samples collected from distinct Brazilian localities. Among the analyzed specimens, a large degree of cytogenetic variation related to diploid numbers and karyotype structure was observed, with karyotypes showing 2n=42, 44 and 46 chromosomes. In addition, using sequences of three mitochondrial genes, the phylogenetic relationships between every sample with a known karyotype were determined, which revealed significant nucleotide divergence among the karyomorphs. Also, the analyses indicate that chromosomal rearrangements occurred independently within the distinct lineages of S. marmoratuscomplex, which resulted in the appearance of distinct karyotypic variants in a non-linear fashion related to diploid numbers and in the appearance of similar non-homologous chromosomes. Finally, the integration of both molecular cytogenetic and phylogenetic approaches allowed the determination of specific chromosomes possibly involved in rearrangements and a better understanding about the evolutionary processes involved in the differentiation ofSynbranchusgenus.

  6. Screening probiotic candidates for a mixture of probiotics to enhance the growth performance, immunity, and disease resistance of Asian seabass, Lates calcarifer (Bloch), against Aeromonas hydrophila.

    Science.gov (United States)

    Lin, Hsueh-Li; Shiu, Ya-Li; Chiu, Chiu-Shia; Huang, Shih-Ling; Liu, Chun-Hung

    2017-01-01

    Six bacteria, including, Lactobacillus casei M15, Lac. plantarum D8, Lac. pentosus BD6, Lac. fermentum LW2, Enterococcus faecium 10-10, and Bacillus subtilis E20, and one yeast, Saccharomyces cerevisiae P13 were selected as probiotics for Asian seabass, Lates calcarifer, by tracking the growth performance and disease resistance of fish against Aeromonas hydrophila in the first trial. The probiotic efficiency screening results showed that B. subtilis E20 and Lac. pentosus BD6, and S. cerevisiae P13 and Lac. fermentum LW2 respectively improved either the growth performance or disease resistance. Therefore, these four probiotics were then selected to prepare a probiotics mixture, and this was incorporated in equal proportions into diets for Asian seabass at levels of 0 (control), and 106 (MD6), 107 (MD7), 108 (MD8), and 109 (MD9) colony-forming units (cfu) (kg diet)-1. A synergistic effect of the combined probiotics was investigated in this study, and the probiotics mixture was able to improve both the growth performance and health status of fish. After 56 days of feeding, fish fed the MD9 diet had a higher final weight and percentage of weight gain. In addition, protein contents in the dorsal muscle of fish fed the MD8 and MD9 diets were significantly higher compared to the control. For the pathogen challenge test, fish fed the MD7, MD8, and MD9 diets had significantly lower cumulative mortalities after A. hydrophila infection compared to those of fish fed the control and MD6 diets, which might have been due to increased respiratory bursts, decreased superoxide dismutase activity in leucocytes, and increased phagocytic activity. Therefore, we considered that the probiotics mixture could adequately provide probiotic efficiency for Asian seabass, and the diet containing 109 cfu (kg diet)-1 probiotic mixture is recommended to improve the growth and health status of Asian seabass. Copyright © 2016. Published by Elsevier Ltd.

  7. Some observations on the morphometry and biology of Psettodes erumei (Bloch) and Pseudorhombus arsius (Hamilton-Buchanan) from the Goa region

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    The metric and meristic characters of Psettodes erumei and Pseudorhombus arsius from the nearshore waters of Goa have been studied. The meristic characters of these two species showed considerable variations. However, the number of vertebrae in P...

  8. "Candidatus Similichlamydia laticola", a novel Chlamydia-like agent of epitheliocystis in seven consecutive cohorts of farmed Australian barramundi, Lates calcarifer (Bloch.

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    Megan C Stride

    Full Text Available Six consecutively hatched cohorts and one cohort of pre-hatch eggs of farmed barramundi (Lates calcarifer from south Australia were examined for Chlamydia-like organisms associated with epitheliocystis. To identify and characterise the bacteria, 59 gill samples and three pre-hatch egg samples were processed for histology, in situ hybridisation and 16S rRNA amplification, sequencing and comprehensive phylogenetic analysis. Cases of epitheliocystis were observed microscopically and characterised by membrane-enclosed basophilic cysts filled with a granular material that caused hypertrophy of the epithelial cells. In situ hybridisation with a Chlamydiales-specific probe lead to specific labelling of the epitheliocystis inclusions within the gill epithelium. Two distinct but closely related 16S rRNA chlamydial sequences were amplified from gill DNA across the seven cohorts, including from pre-hatch eggs. These genotype sequences were found to be novel, sharing 97.1 - 97.5% similarity to the next closest 16S rRNA sequence, Ca. Similichlamydia latridicola, from Australian striped trumpeter. Comprehensive phylogenetic analysis of these genotype sequences against representative members of the Chlamydiales order and against other epitheliocystis agents revealed these Chlamydia-like organisms to be novel and taxonomically placed them within the recently proposed genus Ca. Similichlamydia. Following Fredricks and Relman's molecular postulates and based on these observations, we propose the epitheliocystis agents of barramundi to be known as "Candidatus Similichlamydia laticola" (sp. nov..

  9. Genetic variation in the mitochondrial genome of the giant grouper Epinephelus lanceolatus (Bloch, 1790 and its application for the identification of broodstock

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    Seng S. Cheng

    2015-11-01

    Full Text Available Mitochondrial DNA (mtDNA markers are ideal for the validation of maternal inheritance and the identification of brood-stock in aquaculture breeding programs. The complete mitochondrial genomes of 11 species of grouper are currently available at the GenBank. This study was directed towards the characterization of mtDNA loci which can be applied for identification of interspecific F1 hybrids developed from Epinephelus fuscoguttatus and Epinephelus lanceolatus in aquaculture breeding programs. DNA was extracted from the fin clip of one specimen of E. lanceolatus which the source of sperm for the artificial spawning of the interspecific F1 hybrid E. fuscoguttatus × E. lanceolatus. Specific primers were designed to amplify the DNA after comparative analysis of the mtDNA genomes available at the GenBank. The primers were applied to test for cross-amplification in F1 hybrids as well as in the maternal parent E. fuscoguttatus (Forsskål, 1775 and the genetically related species Epinephelus coioides and Epinephelus corallicola (Valenciennes, 1828. DNA sequence analysis revealed that the Malaysian variety of E. lanceolatus exhibited variation at 11 of the 13 ORFs when compared to the variety from Taiwan. A distinct segmented duplication was observed in the D-loop region which was determined to be unique to the E. lanceolatus specimen obtained from Sabah, Malaysia. Cross amplification of mtDNA loci in the groupers E. fuscoguttatus, E. coioides, E. corallicola and the F1 hybrid of E. fuscoguttatus × E. lanceolatus revealed distinct profiles for each of the species with a clear indication that mtDNA were inherited from the maternal parent of the F1 hybrid.. mtDNA loci can be applied by fish breeders to determine interspecific hybridization events.

  10. Physiologic implications of inter-hormonal interference in fish: lessons from the interaction of adrenaline with cortisol and thyroid hormones in climbing perch (Anabas testudineus Bloch).

    Science.gov (United States)

    George, Nimta; Peter, Valsa S; Peter, M C Subhash

    2013-01-15

    Adrenaline and cortisol, the major stress hormones, are known for its direct control on stress response in fish. Likewise, as an important stress modifier hormone, thyroid hormone has also been implicated in stress response of fish. We tested whether the hypothesis on the phenomenon of inter-hormonal interference, a process that explains the hormonal interactions, operates in fish particularly between adrenaline, cortisol and thyroid hormones. To achieve this goal, indices of acid-base, osmotic and metabolic regulations were quantified after adrenaline challenge in propranolol pre-treated air-breathing fish (Anabas testudineus). Short-term adrenaline (10 ng g(-1)) injection for 30 min produced a rise in plasma cortisol without affecting plasma T(3) and T(4). On the contrary, blocking of adrenaline action with a non-selective blocker, propranolol (25 ng g(-1)) for 90 min reduced plasma cortisol along with plasma T(4) and that indicate a possible interference of these hormones in the absence of adrenaline challenge. Similarly, a reduction in plasma T(3) was found after adrenaline challenge in propranolol pre-treated fish and that suggests a functional synergistic interference of adrenaline with T(3). Adrenaline challenge in these fish, however, failed to abolish this propranolol effect. The remarkable systemic hypercapnia and acidosis by propranolol pre-treatment were reversed by adrenaline challenge, pointing to a direct action of adrenaline on acid-base indices probably by a mechanism which may not require β-adrenergic receptor systems. Interestingly, the prominent adrenaline-induced hyperglycemia, hyperlactemia and hyperuremea were not altered by propranolol treatment. Similarly, adrenaline challenge promoted and propranolol reduced the osmotic competencies of the gills, kidneys and liver of this fish as evident in the sodium and proton pump activities. The modified physiologic actions of adrenaline and its modified interaction with THs and cortisol in blocked fish indicate an interaction of adrenaline with cortisol and THs. Our physiologic evidences thus support the hypothesis of the phenomenon of inter-hormonal interference. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Food and feeding habits of king weakfish, Macrodon ancylodon (Bloch & Schneider, 1801 caught in the southern coast of Brazil (lat, 29º to 32ºs

    Directory of Open Access Journals (Sweden)

    Anastácio Afonso Juras

    1985-01-01

    Full Text Available Macrodon ancylodon was obtained from landings in Santos Port (São Paulo State of fish caught monthly by commercial vessels, on the southern coast of Brazil during September 1976 to August 1977. The measurements of total lenght, total weight determination of sex and maturity stages were made. The food items found in stomach contents were: shrimp (Artemesia longinaris, fishes (Paralonchurus brasiliensis, Macrodon ancylodon, Trichirus lepturus, Gadidae, Engraulidae, molluscs (Loliginidae, Bivalvia and Stomatopoda. Widening of food spectrum was observed in winter. The index of preponderance showed that immature females, immature and mature males fed predominantly on shrimp, while mature females fed mainly on fishes. During spring and summer (spawning season M. ancylodon exhibited relatively low percentage of full stomachs. Cannibalism was encountered more intensively for mature fish.

  12. Efficacy of exogenous hormone (GnRHa) for induced breeding of climbing perch Anabas testudineus (Bloch, 1792) and influence of operational sex ratio on spawning success.

    Science.gov (United States)

    Mandal, Babita; Kumar, Rajesh; Jayasankar, P

    2016-08-01

    The climbing perch, Anabas testudineus, is an air-breathing fish having great consumer preference as a food fish and is considered a prime candidate species for aquaculture. Spawning success is an important issue while using hormones for captive induced breeding. In the first experiment, a trial was conducted to assess the efficacy of a synthetic Gonadotropin Releasing Hormone analog (sGnRHa) on the spawning success of climbing perch. Female fish were administered six different doses each with a single intramuscular injection of sGnRHa hormone at 0.002 (TOD1), 0.005 (TOD2), 0.01 (TOD3), 0.015 (TOD4), 0.02 (TOD5), 0.03 (TOD6) μg/g body weight. Similarly, males were administered half of the hormone dose of females in all the respective treatment groups. The greatest (Pclimbing perch. For this study a different female to male ratio (1:1, 1:2, 1:3 and 1:4) and male to female ratio (1:1, 1:2 and 1:3) were used. There were a greater (Pclimbing perch. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Dietary amino acid L-tryptophan requirement of fingerling Indian catfish, Heteropneustes fossilis (Bloch), estimated by growth and haemato-biochemical parameters.

    Science.gov (United States)

    Ahmed, Imtiaz

    2012-08-01

    An 8-week feeding trial was conducted to determine the dietary tryptophan requirement of fingerling Indian catfish, Heteropneustes fossilis (6.10 ± 1.15 cm, 4.44 ± 0.50 g). Six isonitrogenous (40 g 100 g⁻¹) and isoenergetic (17.90 kJ g⁻¹) amino acid test diets were formulated with gradation of 0.1 g 100 g⁻¹ containing graded levels of L-tryptophan (0.04-0.54 g 100 g⁻¹, dry diet). Fish were stocked in triplicate groups, in 75-L circular trough with flow-through system and fed experimental diets at 4% BW/day twice daily. Maximum live weight gain (258%), best feed conversion ratio (FCR) (1.54) and protein efficiency ratio (PER) (1.62) were obtained in fish fed diet containing 0.34 g 100 g⁻¹ tryptophan. However, quadratic regression analysis of weight gain, FCR, PER and body protein deposition (BPD) data indicated requirements for dietary tryptophan at 0.37, 0.33, 0.32 and 0.33 g 100 g⁻¹ of dry diet, respectively. Significantly (P tryptophan diet. Ash content was not significantly different (P > 0.05) among treatments except for diets 0.04 and 0.14 g 100 g⁻¹. Excellent somatic and haematological indices values were obtained at the requirement level. Based on above results, it is recommended that the diet for H. fossilis should contain tryptophan at 0.32 g 100 g⁻¹, dry diet, corresponding to 0.80 g 100 g⁻¹ dietary protein for optimum growth and efficient feed utilization.

  14. Histological characteristic of interrenal and chromaffin cells in relation to ovarian activities in Mystus vittatus (Bloch during growth, maturation, spawning and post-spawning phases

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    Padmanabha Chakrabarti

    2016-09-01

    Full Text Available The histological status of adrenocortical tissues and the correlated seasonal changes in ovarian activities in Mystus vittatus was performed. The tubules and nests of interrenal and chromaffin cells were located in cephalic kidney around the main branches of posterior cardinal vein. Various female germ line cells were identified in the ovary based on size, distinctive features and histoarchitechture of the cells. However, on the basis of relative abundance and size of the different oocytes, the event of oogenesis has been found to occur in four distinct phases, including growth, maturation, spawning and post-spawning. The cytoplasmic features and the architecture of the interrenal and chromaffin cells varied during different phases of the reproductive cycle. During growth and maturation phases, the amount of cytoplasmic granules of interrenal cells increased than chromaffin cells that was in coincidence with the increase of early and late perinucleolar oocytes followed by highest frequency percentage of oocyte at stages IV and V. The cytoplasmic mass of interrenal cells was gradually elevated along with hypertrophied nuclei from the end of maturation and spawning phases also correlated with the increased frequency of mature oocytes. Therefore, gradual accumulation of cytoplasmic granules in the interrenal cells was noticed during post-spawning phase. The cytological variations in the interrenal and chromaffin cells harmonized with constitution of different ovarian cells during different reproductive phase in M. vittatus.

  15. Chronic stress due to high stocking density in open sea cage farming induces variation in biochemical and immunological functions in Asian seabass (Lates calcarifer, Bloch).

    Science.gov (United States)

    Sadhu, Narasimhulu; Sharma, S R Krupesha; Joseph, Shoji; Dube, Praveen; Philipose, K K

    2014-08-01

    Stocking density is an important factor in cage aquaculture of finfish. Effects of high stocking density (35 fish cubic m(-1)) on a range of biochemical and immunological parameters in Asian seabass reared in open sea floating net cages were compared to fish held in relatively low density (15 fish cubic m(-1)). The results revealed that chronic stress due to high stocking density induced variations in most of the parameters studied as evidenced by increased cortisol and glucose levels and decreased activity of lysozyme, myeloperoxidase and complement. Production of reactive oxygen species, total leucocyte count and total serum protein were also decreased, whereas anti-protease, alkaline phosphatase and acid phosphatase activities were increased in high stocking-density group when compared to low stocking-density group. Effects of chronic stress due to high stocking density were discussed in relation to variations in these parameters.

  16. The effect of temperature on the embryonic development of barramundi, the Australian strain of Lates calcarifer (Bloch using current hatchery practices

    Directory of Open Access Journals (Sweden)

    Valentin Thépot

    2015-11-01

    Full Text Available Lates calcarifer (barramundi or Asian seabass has been farmed since the 1970s, yet despite its widespread culture little has been documented on the species’ embryonic development and particularly how development relates to temperature. This is particularly the case for the Australian L. calcarifer genetic strain. Accordingly, embryonic development of fertilised barramundi eggs incubated at 26, 28, 30, 32, 34 and 36 °C were followed from the time of incubation until hatching and the timing to reach key developmental stages and temperature-induced hatching success established. Eggs incubated at 26 and 36 °C did not survive past the first two hours post-fertilisation. Development of the Australian strain of L. calcarifer was observed to proceed similarly to those documented from Asia, however, differences were observed in the timing of major embryonic events among the two strains. Incubation trials showed that eggs maintained at 30 °C had the highest hatch rate (86.7%. The findings of this study are discussed and put in a commercial context with potential future research to further improve practices at the hatchery level.

  17. Annual changes in serum calcium and inorganic phosphate levels and correlation with gonadal status of a freshwater murrel, Channa punctatus (Bloch

    Directory of Open Access Journals (Sweden)

    S.K. Srivastav

    1998-08-01

    Full Text Available Adult Channa punctatus murrels of both sexes (60-80 g were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960 and Fiske and Subbarow (1925, respectively. Gonads were fixed to judge the state of maturation of the fish. Males exhibited no change in serum calcium levels throughout the year in correlation with testicular maturation. However, serum phosphate levels exhibited a rise in correlation with the increased gonadosomatic index. Females showed marked seasonal changes in serum calcium and phosphate levels which were associated with ovarian maturation (vitellogenesis.

  18. Effects of hirami lemon, Citrus depressa Hayata, leaf meal in diets on the immune response and disease resistance of juvenile barramundi, Lates calcarifer (bloch), against Aeromonas hydrophila.

    Science.gov (United States)

    Shiu, Ya-Li; Lin, Hsueh-Li; Chi, Chia-Chun; Yeh, Shinn-Pyng; Liu, Chun-Hung

    2016-08-01

    The present study was conducted to evaluate the dietary supplementation of leaf meal from Citrus depressa Hayata on the growth, innate immune response, and disease resistance of juvenile barramundi, Lates calcarifer. Four diets were formulated to contain 0% (control), 1% (C1), 3% (C3), and 5% (C5) leaf meal, respectively. During a 56 d feeding trial, fish survival, growth performance, and feed efficiency were not significantly different among all groups. For immune response, respiratory burst, superoxide dismutase and lysozyme activities were not significantly different among all groups. However, fish fed the C5 diet for 56 d had significantly higher phagocytic activity. Also, fish fed C3 and C5 diets had significantly higher Mx gene expressions in spleens and head kidneys with nerve necrosis virus injections after 24 h. Disease resistance against Aeromonas hydrophila was increased by the C5 diet. In this study, barramundi fed on a diet containing 5% C. depressa Hayata leaf meal had significantly better innate immune response and disease resistance against A. hydrophila. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Diferenciação geográfica de Macrodon ancylodon (Bloch & Schneider, 1801 na costa brasileira, entre as latitudes 18º36'S e 32º10'S: etapa I The geographical differentiation of Macrodon ancylodon (Bloch & Schneider, 1801 in the Brazilian coast between Lat. 18º36'S and 32º10'S: phase I

    Directory of Open Access Journals (Sweden)

    Noriyoshi Yamaguti

    1979-06-01

    Full Text Available Multiple range tests according to Kramer, 1956 were performed on 3 meristic and 15 morphometric characters of "pescada-foguete" (Macrodon ancylodon samples collected off coast near Conceição da Barra (Espirito Santo State, Atafona, Macaé, Ubatuba cities, Bom Abrigo Island and Rio Grande do Sul State coast. It was also observed morphological differences in otoliths collected at each region. The number of statistical differences among samples and different morphological characteristics presented by otoliths suggested the existence of four populations along the studied area: (1 along Espírito Santo State coast; (2 near the region between Atafona and Macaé coasts; (3 along São Paulo, Paraná and north Santa Catarina States coasts and (4 along Rio Grande do Sul State coast. Probably the differentiation was caused by different environmental conditions observed among regions. Other papers about life history corroborate these results except for the Espírito Santo population about which there is no biological information up to the moment.

  20. Introduzione ad "Apologia della storia o Mestiere di storico" / Introduction to “Apologia for History or the Historian’s Craft”

    National Research Council Canada - National Science Library

    Marc Bloch

    2013-01-01

    Si ripubblica qui l’Introduzione ad Apologia della storia o Mestiere di storico di Marc Bloch nella nuova edizione curata dal figlio Etienne Bloch nel 1993 e tradotta per la prima volta in italiano nel 1998...

  1. Obituaries and biographical notes

    NARCIS (Netherlands)

    NN,

    1969-01-01

    Bailey, Irving Widmer (1884-1967) R.H. Wetmore, Phytomorphology 18 (1968) 294-298, phot. Dennstedt, A.W. H. Manitz, August Wilhelm Dennstedt’s Schlüssel zum Hortus Indicus Malabaricus. Taxon 17 (1968) 496-501, 2 tab.). — Rather extensive survey; validly published names are listed, as well as the

  2. Metazoários parasitos de seis espécies de peixes do Reservatório de Lajes, Estado do Rio de Janeiro, Brasil Metazoan parasites of six fishes species from Lajes Reservoir in the State of Rio de Janeiro, Brazil

    National Research Council Canada - National Science Library

    Aline R. Paraguassú; José L. Luque

    2007-01-01

    ... parasitárias. A maioria dos espécimes de H. affinis (95,6%) e H. malabaricus (84,6%) estavam parasitados por pelo menos uma espécie de metazoário. Em A. bimaculatus, A. fasciatus, L. castaneus e T. striatulus 41%, 39,2%, 56,7% e 14,7% dos...

  3. Análisis morfométrica y merística en sapo lusitánico Halobatrachus didactylus (Bloch and Schneider, 1801): Evidencia de fragmentación poblacional en la costa portuguesa

    OpenAIRE

    José Lino Costa; Pedro Raposo de Almeida; María José Costa

    2003-01-01

    Para investigar la hipótesis de fragmentación de las poblaciones portuguesas de sapo lusitánico Halobatrachus didactylus, se han analizado un total de 207 ejemplares de esta especie, provenientes de seis localidades distintas, a nivel de sus características morfométricas y merísticas. El estudio ha confirmado el aislamiento relativo de las poblaciones del Algarve y de sus homólogas de los estuarios de la costa occidental, demostrando estas últimas, de igual modo, un elevado grado de aislamien...

  4. Cultivo Integral de dos especies de escómbridos: Atún rojo del Atlántico (Thunnus thynnus, L. 1758) y Bonito Atlántico (Sarda sarda, Bloch 1793)

    OpenAIRE

    Ortega-García, A. (Aurelio)

    2015-01-01

    Los escómbridos comprenden una familia de peces pelágicos con un gran potencial para la acuicultura debido a su rápido crecimiento y alto valor comercial. Con la excepción del Atún rojo del pacífico (Thunnus orientalis), especie en la que se ha completado el ciclo vital, la acuicultura integral de las especies pertenecientes a la familia de los escómbridos o es inexistente o se basa en la captura de especímenes adultos. Esta tesis pretende establecer las bases de la reproducción y cultivo lar...

  5. Cultivo integral de dos especies de escómbridos : Atún rojo del Atlántico (Thunnus thynnus, L. 1758) y Bonito Atlántico (Sarda sarda, Bloch 1793)

    OpenAIRE

    Ortega García, Aurelio

    2015-01-01

    Scombridae comprise a family of pelagic fish species with a great potential for aquaculture due to fast growth rates and high commercial values. In the last years, it has been complete the life cycle in captivity of Pacific bluefin tuna (Thunnus orientalis), but with this exception, integral Aquaculture of species belonging to Scombriae does not exist or is capture-based. This thesis pretends to determine the basis for reproduction and larval rearing of two species of scombrids: Atlantic b...

  6. ESTRUCTURA DE LA MACROFAUNA DE INVERTEBRADOS PRESENTE EN LOS NIDOS DEL PEZ MALACANTHUS PLUMIERI (BLOCH, 1786 (PERCIFORMES: MALACANTHIDAE EN LA BAHÍA DE NENGUANGE, PARQUE NACIONAL NATURAL TAYRONA, MAR CARIBE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    GUTIÉRREZ-SALCEDO JOSÉ MANUEL

    2007-12-01

    Full Text Available Se realizó la caracterización de la estructura de invertebrados presentes en losmontículos de nidos del pez Malacanthus plumieri durante el segundo semestre de2003, en la bahía de Nenguange, con el fin de establecer diferencias entre dos gruposde nidos diferenciados por su profundidad (5 y 17 m. Se colectaron en total 1760individuos pertenecientes a 152 especies de siete Phyla, la mayoría de las cualesse encuentra asociadas a sustratos rocosos, arrecifes, fondos blandos y cascajo.Por medio de un análisis ecológico multivariado, se estableció la estructura de lacomunidad, además, se calcularon los principales atributos ecológicos tales comoriqueza, abundancia, diversidad, uniformidad y equidad para cada uno de los gruposde nidos establecidos previamente. La caracterización de la comunidad mostró lapresencia de 32 especies generalistas (presentes en los dos grupos de nidos de lascuales Brachycarpus biunguiculatus, Micropanope spinipes y Synalpheus fritzmuelleri tienen una frecuencia relativa superior al 70% cada una. En la franja de los 5 m deprofundidad se colectaron, además de las generalistas, 39 especies características (ej.Mithrax sculptus y Mithrax forceps y 38 especies representadas por un solo individuo.En la franja de los 17 m de profundidad se presentaron 19 especies características(ej. Munida angulata y Petrolisthes galathinus y 24 especies representadas porun solo individuo. Los atributos ecológicos evaluados no mostraron diferenciassignificativas entre las dos franjas batimétricas; el índice de correlación tampocomostró una influencia directa entre el perímetro de los montículos y la estructura dela comunidad

  7. Description of Poecilia (Acanthophacelus) wingei n. sp. from the Paría Peninsula, Venezuela, including notes on Acanthophacelus Eigenmann, 1907 and other subgenera of Poecilia Bloch and Schneider, 1801 (Teleostei, Cyprinodontiformes, Poeciliidae)

    NARCIS (Netherlands)

    Poeser, F.N.; Kempkes, M.; Isbrücker, I.J.H.

    2005-01-01

    The taxonomy of the common guppy, Poecilia reticulata Peters, 1859, is reviewed and the closely related Campoma guppy, P. wingei n. sp., is described. Formerly, the common guppy was not judged to be closely related to any other species of Poecilia, but the new species is the second species to be

  8. Wave propagation in structured materials as a platform for effective parameters retrieving

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Ha, S.; Sukhorukov, A. A.

    utilization of the Bloch-mode analysis5. The idea is to perform the Bloch mode expansion6 of the field inside the metamaterial slab when it is illuminated with a plane wave incident from vacuum. Then we determine the effective refractive index from the propagation constant of the dominating (fundamental......) Bloch mode. The Bloch and wave impedances are determined by definition as the proportionality coefficient between electric and magnetic fields of the fundamental Bloch mode volume or surface averaged over the unit cell1. The ratio of the surface averaged fields provides the value of the Bloch impedance...... and, respectively, enables the retrieval of wave EPs. The volume averaging provides the wave impedance, which is needed for the retrieval of the materials parameters. The main advantage of our method is its simple numerical realization. The first part of the method involves the extraction...

  9. Browse Author Index - African Journals Online

    African Journals Online (AJOL)

    Bloch, C.E. · Bloch, E.M. · Bloch, J.M. · Block, B · Blockman, M · Blockman, Marc · Blockman, Marc · Blom, D J · Blom, D J · Blom, MW · Bloom, Peter D · Blumberg, L · Blumberg, LH · Blumberg, Lucille · Blumenthal, N. J. · Blumenthal, R · Blumenthal, Ryan 401 - 450 of 740 Items >>. ISSN: 0256- ...

  10. Hydrophylax bahuvistara, a new species of fungoid frog (Amphibia: Ranidae from peninsular India

    Directory of Open Access Journals (Sweden)

    Anand D. Padhye

    2015-09-01

    Full Text Available Hydrophylax bahuvistara, a new species of fungoid frog, is described from peninsular India. It can be separated from its congeners based on a combination of characters including wider head, outline of snout in dorsal view truncated, finger and toe tips without lateroventral groove, foot moderately webbed, metatarsals of 4th and 5th toes closely set, outer metatarsal tubercle small, foot length less than or equal to half of snout vent length, dorsal parts of shank without glandular folds and sparse horny spinules, and heels touch each other when the legs are folded at right angles to the body.  Genetically, H. bahuvistara forms a monophyletic group with H. malabaricus as a sister clade separated by a raw distance of 4.0 to 4.5% in the 16s rRNA gene.  Morphometrically, H. bahuvistara forms a significantly different cluster from H. malabaricus and H. gracilis in Discriminant Analysis.  

  11. The Fundamental Group and Extensions of Motives of Jacobians of ...

    Indian Academy of Sciences (India)

    57

    2016-09-07

    Sep 7, 2016 ... [Blo84] Spencer Bloch. Algebraic cycles and values of L-functions. J. Reine Angew. Math., 350:94–108, 1984. [Blo00] Spencer J. Bloch. Higher regulators, algebraic K-theory, and zeta functions of elliptic curves, vol- ume 11 of CRM Monograph Series. American Mathematical Society, Providence, RI, 2000.

  12. From lanosterol to cholesterol: Structural evolution and differential effects on lipid bilayers

    DEFF Research Database (Denmark)

    Miao, Ling; Nielsen, Morten; Thewalt, J.

    2002-01-01

    Cholesterol is an important molecular component of the plasma membranes of mammalian cells. Its precursor in the sterol biosynthetic pathway, lanosterol, has been argued by Konrad Bloch (Bloch, K. 1965. Science. 150:19-28; 1983. CRC Crit Rev. Biochem. 14:47-92; 1994. Blonds in Venetian Paintings...

  13. Juudi naise pilt purustas hinnarekordi / Eda Post

    Index Scriptorium Estoniae

    Post, Eda, 1983-

    2006-01-01

    Miljardär Roland Lauderile kuuluv New Yorgi saksa ja austria kunsti muuseum Neue Galerie ostis 135 miljoni dollari eest austria kunstniku Gustav Klimti õlimaali "Kuldne Adele" Adele Bloch-Bauerist. Lähemalt maali valmimisest ja saatusest. Bloch-Baueri kunstikogu saatusest

  14. Properties of superposition operators acting between Bμ∗ and QK∗

    Directory of Open Access Journals (Sweden)

    Alaa Kamal

    2015-10-01

    Full Text Available In this paper we introduce natural metrics in the hyperbolic Bloch and QK-type spaces with respect to which these spaces are complete. Moreover, Lipschitz continuous, bounded and compact superposition operators Sϕ from the hyperbolic Bloch type space to the hyperbolic QK-type space are characterized by conditions depending only on the analytic symbol ϕ.

  15. Uso de biomarcador histopatológico em brânquias de Centropomus undecimalis (Bloch, 1972 na avaliação da qualidade da água do Parque Ecológico Laguna da Jansen, São Luís - MA

    Directory of Open Access Journals (Sweden)

    S.M. Cantanhêde

    2014-04-01

    Full Text Available Com o objetivo de analisar a intensidade das alterações histológicas em brânquias de Centropomus undecimalis para avaliar a qualidade da água do Parque Ecológico Laguna da Jansen, em São Luís, Estado do Maranhão, coletaram-se exemplares de peixes no período chuvoso de 2012 e amostras de água nos períodos seco de 2011 e chuvoso de 2012 para análises físico-química e bacteriológica. Os resultados mostraram que a maioria dos parâmetros físico-químicos e bacteriológicos estava de acordo com os valores estabelecidos pela Resolução do CONAMA nº 357 de 2005. As alterações histológicas observadas foram: elevação do epitélio lamelar; proliferação excessiva de células dos epitélios filamentar e lamelar causando fusão total ou parcial das lamelas; alteração da estrutura das lamelas; hiperplasia das células mucosas; ruptura do epitélio lamelar; espessamento descontrolado do tecido proliferativo filamentar e lamelar e aneurismas de vários tamanhos. Também foi observada a presença de parasito em alguns exemplares. O Índice de Alteração Histológica (IAH por indivíduo variou de 2 a 114. O valor médio do IAH obtido foi de 40,3, demonstrando que as brânquias dos indivíduos amostrados da espécie C. undecimalis apresentaram alterações de moderadas para severas no tecido. As alterações histológicas encontradas indicam que esses indivíduos desenvolveram mecanismos de defesa contra a ação de estressores presentes na água da laguna e a um provável desequilíbrio parasito-hospedeiro-ambiente associado à baixa qualidade do ambiente.

  16. High-Q submicron-diameter quantum-dot microcavity pillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Dunzer, Florian

    and allowing for a single localized mode inside the cavity. The fundamental Bloch mode experiences an adiabatic transition, leading to an improved mode matching and a reduced coupling to propagating Bloch modes in the DBRs. The central GaAs layer incorporating quantum dots is only 60 nm thick corresponding...... to ≈ λ/5, and regular cavity concepts are thus insufficient to explain the localization of the cavity mode, demonstrating the necessity of Bloch-wave formalism in the analysis of the design. We compare our adiabatic design to a reference incorporating a λ-spacer. A theoretical improvement of Q of two...

  17. The effects of next-to-nearest-neighbour hopping on Bose–Einstein ...

    Indian Academy of Sciences (India)

    - to-nearest-neighbour boson hopping (t ) energy on Bose–Einstein condensation in cubic lattices. We consider both non-interacting and repulsively interacting bosons moving in the lowest Bloch band. The interacting bosons are studied using ...

  18. Croissance et âge des poissons capitaines: Polydactylus quadrifilis ...

    African Journals Online (AJOL)

    Croissance et âge des poissons capitaines: Polydactylus quadrifilis (Cuvier, 1829), Galeoides decadactylus (Bloch, 1795) et Pentanemus quinquarius (Linné, 1758) de la pêcherie artisanale maritime de Grand-Lahou (Côte d'Ivoire)

  19. Wave propagation in metamaterials and effective parameters retrieving

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Ha, S.; Sukhorukov, A.

    2011-01-01

    as handsome for implementation. We set a goal to develop a method which is unambiguous but at the same time simple and straightforward. We assume that this can be done by observing the wave propagation inside a metamaterial slab thick enough to avoid transient effects. First, we formulated a retrieval method...... with a plane wave incident from vacuum. Then we determine the effective refractive index from the propagation constant of the dominating (fundamental) Bloch mode. The Bloch and wave impedances are determined by definition as the proportionality coefficient between the electric and magnetic fields...... complex wave effective parameters. Extending the method further we developed the approach to determine both wave and material effective parameters through the Bloch-mode analysis [3]. The idea is to perform the Bloch mode expansion [4] of the field inside the metamaterial slab when it is illuminated...

  20. Wide-angle beam splitting by use of positive-negative refraction in photonic crystals.

    Science.gov (United States)

    Luo, Ye; Zhang, Wei; Huang, Yidong; Zhao, Jianhui; Peng, Jiangde

    2004-12-15

    We present a positive-negative refraction effect in which, under certain conditions, an incident plane wave launched into a photonic crystal excites a positive-refracted Bloch wave and a negative-refracted Bloch wave simultaneously, both of which maintain the polarization. By utilizing this phenomenon, wide-angle beam splitting can be realized at the microscale level. Numerical simulations are employed to demonstrate this anomalous refraction behavior.

  1. H.E. Mr Leonid A. Skotnikov, Ambassador, Permanent Representative of the Russian Federation to the United Nations and other International Organisations in Geneva

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Photo 01: H.E. Mr Leonid A. Skotnikov, Ambassador of the Russian Federation to the United Nations and other International Organisations in Geneva (centre) with (from left to right) V. Kaftanov, Ph. Bloch, N. Koulberg, F. Grishaev Photo 02: H.E. Mr Leonid A. Skotnikov, Ambassador of the Russian Federation to the United Nations and other International Organisations in Geneva (centre) with Ph. Bloch (behind the Ambassador, V. Kaftanov) visiting the crystal laboratory in building 27.

  2. The Laughter as Hope Principle

    Directory of Open Access Journals (Sweden)

    Mateus Domingues da Silva

    2015-04-01

    Full Text Available The work aims to establish a parallel between the concept of laughter and the Hope Principle of Ernst Bloch, differentiating their relationship between the pursuit of individual happiness, said to be ideological, deceptive and precarious, and the pursuit of collective happiness, altruistic, that despite utopian it is also true and real, just for being selfless and real because, as a collective expression, indicating concretely and politically, is a real possibility.Keywords: Laughter, Hope Principle, Ernest Bloch, altruism.

  3. Weighted composition operators from Bergman-type spaces into ...

    Indian Academy of Sciences (India)

    Abstract. Let ϕ be an analytic self-map and u be a fixed analytic function on the open unit disk D in the complex plane C. The weighted composition operator is defined by. uCϕf = u · (f ◦ ϕ), f ∈ H(D). Weighted composition operators from Bergman-type spaces into Bloch spaces and little. Bloch spaces are characterized by ...

  4. Klimti tööd tagasi saanud juudi pere müüb need maha

    Index Scriptorium Estoniae

    2006-01-01

    Klimti maalide "Kasemets/Pöögimets" (1901), "Adele Bloch-Bauer II" (1912), "Õunapuu" (1912) ja "Majad Unterachis Attersee ääres" (1916) õiguspäraseks omanikuks tunnistati Ferdinand Bloch-Baueri vennatütar Maria Altmann. Maalid müüakse sügisel. Praegu asuvad maalid New Yorgis saksa ja austria kunsti muuseumis Neue Galerie's

  5. Infection of Anisakis sp. larvae in some marine fishes from the southern coast of Kulon Progo, Yogyakarta

    Directory of Open Access Journals (Sweden)

    SENNY HELMIATI

    2011-01-01

    Full Text Available Setyobudi E, Soeparno, Helmiati S (2011 Infection of Anisakis sp. larvae in some marine fishes from the southern coast of Kulon Progo, Yogyakarta. Biodiversitas 12: 34-37. The prevalence, intensity and distribution of Anisakis sp. larvae which infected some fishes at the southern coast of Kulon Progo District were investigated. Totally 95 fish specimens were collected during December 2007. Results of the present study indicated that the Anisakis sp. larvae infected various fish species i.e: Trichiurus lepturus, Parupeneus sp., Lutjanus malabaricus, Terapon jarbua and Caesio sp. Prevalence and mean intensity of infection showed the differences between fish species. The highest mean intensity of infection was found in L. malabaricus (7.71 larvae/infected host and T. Lepturus (3.18 larvae/infected host, while the lowest intensity of infection was found in Parupeneus sp., T. jarbua and Caesio sp. (1 larvae/infected host. Infected host organs were body cavities (peritoneum, digestive tract, gonads, and liver. Presence of this parasite may be harmful for consumer, however it can be used for several ecological studies as biological tags.

  6. Ferroelectricity of domain walls in rare earth iron garnet films.

    Science.gov (United States)

    Popov, A I; Zvezdin, K A; Gareeva, Z V; Mazhitova, F A; Vakhitov, R M; Yumaguzin, A R; Zvezdin, A K

    2016-11-16

    In this paper, we report on electric polarization arising in a vicinity of Bloch-like domain walls in rare-earth iron garnet films. The domain walls generate an intrinsic magnetic field that breaks an antiferroelectric structure formed in the garnets due to an exchange interaction between rare earth and iron sublattices. We explore 180° domain walls whose formation is energetically preferable in the films with perpendicular magnetic anisotropy. Magnetic and electric structures of the 180° quasi-Bloch domain walls have been simulated at various relations between system parameters. Singlet, doublet ground states of rare earth ions and strongly anisotropic rare earth Ising ions have been considered. Our results show that electric polarization appears in rare earth garnet films at Bloch domain walls, and the maximum of magnetic inhomogeneity is not always linked to the maximum of electric polarization. A number of factors including the temperature, the state of the rare earth ion and the type of a wall influence magnetically induced electric polarization. We show that the value of polarization can be enhanced by the shrinking of the Bloch domain wall width, decreasing the temperature, and increasing the deviations of magnetization from the Bloch rotation that are regulated by impacts given by magnetic anisotropies of the films.

  7. Mechanisms for the symmetric and antisymmetric switching of a magnetic vortex core: Differences and common aspects

    Science.gov (United States)

    Noske, Matthias; Stoll, Hermann; Fähnle, Manfred; Hertel, Riccardo; Schütz, Gisela

    2015-01-01

    Three-dimensional micromagnetic simulations of the switching of a magnetic vortex core in a cylindrical nanodisk are performed, for excitations with out-of-plane fields (symmetric switching) or with various types of time-dependent in-plane fields (asymmetric switching). Although the switching mechanisms are different in detail, all switching events must involve the movement of a Bloch point through the disk, because the switching leads to a change of the Skyrmion number which is a topological invariant as long as there is no action of a Bloch point. The momentary magnetization configurations are different in different layers of the disk. Because of the three-dimensionality it is often difficult to decide whether the asymmetric switching is caused by the splitting of the dip close to the vortex core into a vortex-antivortex pair, and the annihilation of the original vortex with the antivortex (whereby a Bloch point moves). It is suggested that there are situations for which such a switching occurs by the formation of a Bloch point in a configuration which is already similar to a vortex-antivortex configuration, but by a movement of this Bloch point before the formation of a complete pair and without the annihilation of the original vortex with an antivortex.

  8. Terahertz Luminescence and Electrical Characteristics of SiC Structures with Natural Superlattice in Strong Electric Fields

    Science.gov (United States)

    Sankin, V. I.; Andrianov, A. V.; Petrov, A. G.; Zakhar'in, A. O.; Nagalyuk, S. S.; Shkrebiy, P. P.

    2017-12-01

    Recently, the intense terahertz electroluminescence from monopolar n++-n--n+ structures of 8H-SiC natural superlattice at helium temperatures due to Bloch oscillations was found out. In the present work, we compare the THz emission and electrical characteristics of monopolar n++-n--n+ and bipolar n++- π-n+ 8H-SiC structures at 7 K. The bipolar n++- π-n+ 8H-SiC structures were analogous to those on which the negative differential conductivity effect was observed earlier for three polytypes (4H, 6H, and 8H) at T = 300 K. The obtained results allow one to draw a conclusion about common nature of the negative differential conductivity and THz emission effects in the natural superlattice of SiC caused by Bloch oscillations. These results give the proof of fundamental importance supporting the objectivity of postulates of the F. Bloch - C. Zener - G. N. Wannier theory

  9. The effect of thermal fluctuations on Holstein polaron dynamics in electric field

    Science.gov (United States)

    Voulgarakis, Nikolaos K.

    2017-08-01

    In this work, we have studied the effects of thermal fluctuations on the stability of polaron motion under the influence of an external electric field. Zero temperature calculations have been reported previously showing the existence of critical electric field, Ecr, where the system transitions from a stable polaron motion to a Bloch-like oscillation. In this study, we further report that for intermediate polaron sizes the lifetime of such Bloch-like oscillations decay with time due to excessive phonon emission. Our numerical simulations show that the value of Ecr is finite for small temperatures. However, Ecr rapidly decreases with increasing T and becomes practically zero for T > Tcr. In this small but finite temperature window, we report how temperature affects (a) the electric current density, and (b) the Bloch-like frequencies.

  10. Suplementação de vitamina C em dietas para juvenis de trairão

    OpenAIRE

    Ana Lúcia Salaro; Rodrigo Yutaka Dichoff Kasai; Antônio Policarpo Souza Carneiro; Céphora Maria Sabarense; Maria Cristina Ferrarini Nunes Soares Hage; Mateus Moraes Tavares; Jener Alexandre Sampaio Zuanon

    2013-01-01

    O objetivo deste trabalho foi avaliar o efeito da suplementação da dieta com vitamina C no desempenho produtivo, nas alterações morfológicas e no perfil de ácidos graxos da carcaça de juvenis de trairão (Hoplias lacerdae). Utilizou-se o delineamento inteiramente casualizado, com sete tratamentos (0, 17,5, 52,5, 87,5, 122,5, 175 e 350 mg kg-1 de vitamina C na ração) e quatro repetições. Ao final de 62 dias, foram avaliados: ganhos de peso e comprimento, taxas de sobrevivência e canibalismo, un...

  11. Control of Power in Parity-Time -Symmetric Lattices

    CERN Document Server

    Kozlov, Maksim

    2015-01-01

    We investigate wave transport properties of Parity-Time (PT) symmetric lattices that are periodically modulated along the direction of propagation. We demonstrate that in the regime of unbroken PT-symmetry the system Floquet-Bloch modes may interfere constructively leading to either controlled oscillations or linear power absorption and amplification occurring exactly at the phase transition point. The differential power response is effected by the overlap of the gain and loss system distribution with wave intensity pattern that is formed through Rabi oscillations engaging the coupled Floquet-Bloch modes.

  12. Identity Conflicts: A Doctrinal Change Needed?

    Science.gov (United States)

    2014-12-12

    differ from yesterday. ― Marc Bloch, Strange Defeat Introduction The purpose of this thesis is to examine whether the U.S. Army has accepted...Bloch, Marc. 1946. Strange Defeat: A Statement of Evidence Written in 1940. London: W. W. Norton. British Broadcasting Company (BBC). 2006. Iraqi...Raphael. 2010. “A Tale of Two Manuals.” Prism 2, no. 1: 87-100. Collier, Paul, and Anke Hoeffler. 1998. “On Economic Causes of Civil War.” Oxford

  13. Academician Mihail P. Kirpichnikov, Minister for Science and Technology, Russian Federation

    CERN Document Server

    Patrice Loïez

    2002-01-01

    Photo 01: Academician Mihail P. Kirpichnikov, Minister for Science and Technology, Russian Federation (white raincoat) visiting the CMS crystal laboratory with (from l. to r.) Ph. Bloch, N. Koulberg, L. Riabev, First Deputy-Minister, MINATOM; F. Grichaev and A.N. Skrinsky. Photo 02: Academician Mihail P. Kirpichnikov, Minister for Science and Technology, Russian Federation (centre) visiting the CMS crystal laboratory with (from l. to r.) N. Koulberg, M. Koutchina, L. Riabev, First Deputy-Minister, MINATOM; F. Grichaev, Ph. Bloch, A.N. Skrinsky, A. Petrov, V. Stanislavov.

  14. Mrs Hitler and her doctor.

    Science.gov (United States)

    Macleod, Sandy

    2005-12-01

    The doctor who attended the mother of Adolf Hitler in her terminal illness has been blamed as a cause of the Holocaust. The medical details recorded of this professional relationship are presented and discussed. Dr Bloch's medical care of Mrs Hitler was consistent with the prevailing medical practice of the management of fungating breast carcinoma. Indeed, the general practitioner's care and attention of the family appear to have been astute and supportive. There is nothing to suggest that Dr Bloch's medical care was other than competent. Doctors who have the (mis)fortune to professionally attend major figures of history may be unfairly viewed, despite their appropriate and adequate care.

  15. Control of power in parity-time symmetric lattices

    Science.gov (United States)

    Kozlov, Maksim; Tsironis, G. P.

    2015-10-01

    We investigate wave transport properties of parity-time (PT) symmetric lattices that are periodically modulated along the direction of propagation. We demonstrate that in the regime of unbroken PT-symmetry, the system Floquet-Bloch modes may interfere constructively leading to either controlled oscillations or power absorption and unlimited amplification occurring exactly at the phase-transition point. The differential power response is affected by the overlap of the gain and loss system distribution with wave intensity pattern that is formed through Rabi oscillations engaging the coupled Floquet-Bloch modes.

  16. Non-equilibrium analysis of the two-color operation in semiconductor quantum-well lasers

    Energy Technology Data Exchange (ETDEWEB)

    Baeumner, Ada; Koch, Stephan W. [Department of Physics and Material Science Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Moloney, Jerome V. [Arizona Center of Mathematical Science and College of Optical Science, University of Arizona, Tucson 85721, Arizona (United States)

    2011-04-15

    The relevance of hole burning for stable two-color operation in semiconductor quantum-well lasers is studied using a non-equilibrium laser model on the basis of the semiconductor Maxwell-Bloch equations. The field propagation is described via a traveling-wave method. The polarization dynamics is computed using the semiconductor Bloch equations for the microscopic transition and occupation probabilities. Numerical examples for single- and dual-mode operation are presented for a microresonator model system. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Symmetry characterization of electrons and lattice excitations

    Directory of Open Access Journals (Sweden)

    Schober H.

    2012-03-01

    Full Text Available Symmetry concerns all aspects of a physical system from the electronic orbitals to structural and magnetic excitations. In this article we will try to elaborate the fundamental connection between symmetry and excitations. As excitations are manyfold in physical systems it is impossible to treat them exhaustively. We thus concentrate on the two topics of Bloch electrons and phonons. These two examples are complementary in the sense that Bloch electrons describe single particles in an external periodic potential while phonons exemplify a decoupled system of interacting particles. The way we develop the argument gives as by-product a short account of molecular orbitals and molecular vibrations.

  18. Modeling of optical fields in laser microcavities using a modal method

    DEFF Research Database (Denmark)

    Gregersen, Niels

    2013-01-01

    of adiabatic transitions emerge as powerful design tools to control the optical mode. In the modal method, the eld is expanded on the eigenmodes of z-invariant layers and on the Bloch modes of periodic sections. Using mode matching at the interfaces, the method gives direct access to re ection and transmission...... coecients describing the scattering of the optical modes, and the method is thus highly suitable for Bloch-wave engineering of the low-V cavity. As example we have used the modal method to propose the high-Q submicron-diameter micropillar geometry implementing an adiabatic cavity design as illustrated...

  19. A Study to Determine Methods to Improve Patient Awareness at Moncrief Army Hospital, Fort Jackson, South Carolina

    Science.gov (United States)

    1980-04-01

    3Bloch, p. 54. 41bid., p. 53 5Cunningham, p. 68 6Ibid., p. 67. 7Bloch, p. 53. 8Christina Maslach , "Burned-Out," Human Behavior, September 1976, p. 17...Progresa, June 1972, pp. 42- 4 9.. Maslach , Christina. "Burned Out." Human Behavior, September 19.76, pp. 16-21. Sasser, Earl W. Jr. and Frank S...Health Services Command, Fort Sam Houston, Texas, July 1977. Veninga, Robert. "Administrator Burnout - Causes and Cures." Hospital Progress, February 1979

  20. Evaluation of Metabolic Enzymes in Response to Excel Mera 71, a Glyphosate-Based Herbicide, and Recovery Pattern in Freshwater Teleostean Fishes

    OpenAIRE

    Palas Samanta; Sandipan Pal; Aloke Kumar Mukherjee; Apurba Ratan Ghosh

    2014-01-01

    Metabolic enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated in Indian teleostean fishes, namely, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch), for an exposure to 30 days of Excel Mera 71 (17.2 mg/L), a glyphosate formulation, and subsequent depuration under Liv.52, a plant extract at a dose of 187.5 mg/d/250 L for the same period in the same tissues under laboratory condition. ALT activity was sign...

  1. A Higgs at 125.1 GeV and baryon mass spectra derived from a Common U(3) Lie group framework

    DEFF Research Database (Denmark)

    Trinhammer, Ole; Bohr, Henrik; Jensen, Mogens O Stibius

    2015-01-01

    Baryons are described by a Hamiltonian on an intrinsic U(3) Lie group configuration space with electroweak degrees of freedom originating in specific Bloch wave factors. By opening the Bloch degrees of freedom pairwise via a U(2) Higgs mechanism, the strong and electroweak energy scales become...... related to yield the Higgs mass 125.085+/-0.017 GeV and the usual gauge boson masses. From the same Hamiltonian we derive both the relative neutron to proton mass ratio and the N and Delta mass spectra. All compare rather well with the experimental values. We predict neutral flavour baryon singlets...

  2. Selection rule for Dirac-like points in two-dimensional dielectric photonic crystals

    KAUST Repository

    Li, Yan

    2013-01-01

    We developed a selection rule for Dirac-like points in two-dimensional dielectric photonic crystals. The rule is derived from a perturbation theory and states that a non-zero, mode-coupling integral between the degenerate Bloch states guarantees a Dirac-like point, regardless of the type of the degeneracy. In fact, the selection rule can also be determined from the symmetry of the Bloch states even without computing the integral. Thus, the existence of Dirac-like points can be quickly and conclusively predicted for various photonic crystals independent of wave polarization, lattice structure, and composition. © 2013 Optical Society of America.

  3. Taxonomic review of the tree frog genus Rhacophorus from the Western Ghats, India (Anura: Rhacophoridae), with description of ontogenetic colour changes and reproductive behavior.

    Science.gov (United States)

    Biju, S D; Kamei, Rachunliu G; Mahony, Stephen; Thomas, Ashish; Garg, Sonali; Sircar, Gargi; Suyesh, Robin

    2013-01-01

    A taxonomic revision of the Western Ghats species from the genus Rhacophorus is presented. Based on museum studies and new collections from localities spanning the known range of Western Ghats Rhacophorus, we review the four known species of this genus, their type specimens, current taxonomic status and their geographic distribution on the basis of morphological and molecular data. The holotypes of Rhacophorus calcadensis, R. lateralis and R. nialabaricus are redescribed. The previously unidentified holotype of Rhacophorus inalabaricus is herein fixed. Descriptions of ontogenetic colour change (OCC) in the Western Ghats Rhacophorus are provided and we conjecture the taxonomic utility of OCC. Additionally we provide observations on nesting behaviour of each species, and report multiple male participation during amplexus, oviposition and foam nest construction in R. lateralis and R. malabaricus.

  4. An update on the distribution pattern and endemicity of three lesser-known tree species in the Western Ghats, India

    Directory of Open Access Journals (Sweden)

    K. Sankara Rao

    2016-09-01

    Full Text Available The present communication reports an update on the distribution of three endemic tree species of the Western Ghats-Sri Lanka biodiversity hotspot, namely, Atuna indica (Bedd. Kosterm., Paracroton integrifolius (Airy Shaw N.P.Balakr. & Chakrab. and Phaeanthus malabaricus Bedd.  The discovery of these taxa in the Makutta Ghat of Kodagu District results in the extension of their northern range limits and further enriches the flora of Karnataka state by three more tree species.  Within the Western Ghats, these taxa were previously recorded only from the states of Kerala and Tamil Nadu, while Paracroton integrifolius (Airy Shaw N.P.Balakr. & Chakrab. has also been recorded from Sri Lanka.  Nomenclature updates, detailed descriptions, conservation status and relevant notes on the habitat, phenology and distribution localization are supplied.  Additionally, field photographs and scanned herbarium specimens are provided to facilitate easy identification of these taxa in the field. 

  5. 29 March 2011 - Ninth President of Israel S.Peres welcomed by CERN Director-General R. Heuer who introduces Council President M. Spiro, Director for Accelerators and Technology S. Myers, Head of International Relations F. Pauss, Physics Department Head P. Bloch, Technology Department Head F. Bordry, Human Resources Department Head A.-S. Catherin, Beams Department Head P. Collier, Information Technology Department Head F. Hemmer, Adviser for Israel J. Ellis, Legal Counsel E. Gröniger-Voss, ATLAS Collaboration Spokesperson F. Gianotti, Former ATLAS Collaboration Spokesperson P. Jenni, Weizmann Institute G. Mikenberg, CERN VIP and Protocol Officer W. Korda.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    During his visit he toured the ATLAS underground experimental area with Giora Mikenberg of the ATLAS collaboration, Weizmann Institute of Sciences and Israeli industrial liaison office, Rolf Heuer, CERN’s director-general, and Fabiola Gianotti, ATLAS spokesperson. The president also visited the CERN computing centre and met Israeli scientists working at CERN.

  6. Theoretical investigation of the excitonic semiconductor response for varying material thickness: Transition from quantum well to bulk

    DEFF Research Database (Denmark)

    Bischoff, Svend; Knorr, A; Koch, S.W.

    1997-01-01

    For semiconductor slabs with thicknesses varying from the two-dimensional to the three-dimensional limit the linear optical response is calculated numerically by solving the semiconductor Maxwell-Bloch equations. For short-pulse excitation the spatiotemporal dynamics of the electronic mode...

  7. Dynamical theory : Application to spin-echo resolved grazing incidence scattering from periodic structures

    NARCIS (Netherlands)

    Ashkar, R.; Schaich, W.L.; De Haan, V.O.; Van Well, A.A.; Dalgliesh, R.; Plomp, J.; Pynn, R.

    2011-01-01

    Neutron spin-echo resolved grazing incidence scattering (SERGIS) measurements performed on a silicon diffraction grating with a rectangular profile were shown in our previous publications to be well explained by dynamical theory calculations. The theory is based on a Bloch wave expansion of the

  8. Balts show strong notes in Grammy Awards

    Index Scriptorium Estoniae

    2005-01-01

    Los Angeleses 8. veebr. Grammy Awards nominantide seas läti laulja Elina Garanca, dirigendid Paavo Järvi (Schumann "Cello Concerto" and Bloch's "Schelomo") ja Maris Jansons. Eelmisel aastal pälvis Grammy teos Sibelius "Cantatas" (esitajad Ellerheina tütarlastekoor Ester Loitme juhatusel, Eesti Rahvusmeeskoor, ERSO, dirigendid Ants Soots ja Paavo Järvi)

  9. Todorov, Levinas and anti-totalitarian humanism: A perspective on ...

    African Journals Online (AJOL)

    p1243322

    social ideals – Prophetic hope in Emmanuel Levinas and Ernst Bloch) completed at the. Institute of Philosophy, Katholieke Universiteit Leuven (Belgium) in 2005. ... utopias pursue the same obstinate dream: To realize a communion in collective life as perfect as that of conjugal symbiosis.” See also Joachim Fest, Der ...

  10. Download this PDF file

    African Journals Online (AJOL)

    Owner

    wrote of Lagos: Many of the much touted values of contemporary global capital and its prophetic organizational models of dispersal and discontinuity, federalism and flexibility, have .... dreaming and have few ambitions. (qtd in Nebandla 19). Other “impeded futures” (Bloch 33) are the result of the toll of AIDS or high levels of.

  11. Dynamical symmetry breaking of lambda- and vee-type three-level ...

    Indian Academy of Sciences (India)

    between the SU(N) symmetry and the N-level system in general, was investigated extensively in the recent past .... Proceeding in the same way, the semiclassical vee-type three-level system can be written as. HV = HV ...... dimensional Bloch equations and non-linear constants for different configurations of the three-level ...

  12. Introduction to spintronics

    CERN Document Server

    Bandyopadhyay, Supriyo

    2008-01-01

    The Early History of Spin Spin The Bohr Planetary Model and Space Quantization The Birth of "Spin" The Stern-Gerlach Experiment The Advent of Spintronics The Quantum Mechanics of Spin Pauli Spin Matrices The Pauli Equation and Spinors More on the Pauli Equation Extending the Pauli Equation - the Dirac Equation The Time Independent Dirac Equation Appendix The Bloch Sphere The Spinor and the "Qubit" The Bloch Sphere Concept Evolution of a Spinor Spin-1/2 Particle in a Constant Magnetic Field: Larmor Precession Preparing to Derive the Rabi Formula The Rabi Formula The Density Matrix The Density Matrix Concept: Case of a Pure State Properties of the Density Matrix Pure Versus Mixed State Concept of the Bloch Ball Time Evolution of the Density Matrix: Case of Mixed State The Relaxation Times T1 and T2 and the Bloch Equations Spin Orbit Interaction Spin Orbit Interaction in a Solid Magneto-Electric Sub-Bands in Quantum Confined Structures in the Presence of Spin-Orbit Interaction Dispersion Relations of Spin Resolv...

  13. Antropologie en geschiedenis

    NARCIS (Netherlands)

    Kuiper, Yme; Vries, P.H.H.

    1989-01-01

    Since the 1970s there has been a rapprochement in Academia between anthropology and history. Who were the most important advocates of this trend? Forerunners were the British anthropologist and Africanist E.E. Evans-Pritchard and the French historian Marc Bloch. Recent representatives of this trend

  14. Ethical Ideologies: Do They Affect Shopping Behaviors and Perceptions of Morality?

    Science.gov (United States)

    Cho, Hyeon; Yoo, Jeong-Ju; Johnson, Kim K. P.

    2005-01-01

    Counterfeiting is a serious problem facing several industries, including the medical, agricultural, and apparel industries (Bloch, Bush, & Campbell, 1993). The authors investigated whether ethical viewpoints affect perceptions of the morality of particular shopping behaviors, attitudes toward counterfeit products, and intentions to purchase such…

  15. South African Medical Journal - Vol 68, No 1 (1983)

    African Journals Online (AJOL)

    The dilemma of the creatine kinase cardiospecific iso-enzyme (CK-MB) in marathon runners · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. T. H. Diamond, R. Smith, A. P. Goldman, D. P. Myburgh, J.M. Bloch, F Visser, 37-41 ...

  16. Dispersive optical bistability in a nonideal Fabry-Perot cavity II. Numerical results on side-mode instabilities

    NARCIS (Netherlands)

    van Wonderen, A.J.; Suttorp, L.G.

    1991-01-01

    Instabilities in the nearest side-modes are predicted for dispersive optical bistability in a nonideal Fabry-Perot cavity. The results are based on a linear stability analysis of the Maxwell-Bloch equations. This analysis leads to a boundary value problem for a four-dimensional set of linear

  17. Optimally cloned binary coherent states

    DEFF Research Database (Denmark)

    Mueller, C. R.; Leuchs, G.; Marquardt, Ch

    2017-01-01

    Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive...

  18. Nonlinear emission from dark anapole modes and route to all-dielectric metamaterial near-field lasers

    KAUST Repository

    Gongora, J. S. Totero

    2016-08-29

    By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern

  19. Near-Field Nanolasers based on Nonradiating Anapole Modes

    KAUST Repository

    Gongora, J. S. Totero

    2016-05-31

    By employing ab-initio simulations of Maxwell-Bloch equations with a source of quantum noise, we study a new laser concept based on photonic dark-matter nanostructures that emit only in the near-field, with no far-field radiation pattern.

  20. Schrödinger operators on a periodically broken zigzag carbon ...

    Indian Academy of Sciences (India)

    In this paper, we study the spectra of Schrödinger operators on zigzag carbon nanotubes, which are broken by abrasion or during refining process. Throughout this paper, we assume that the carbon nanotubes are broken periodically and we deal with one of those models. Making use of the Floquet–Bloch theory, we ...

  1. A rigorous proof of the Landau-Peierls formula and much more

    DEFF Research Database (Denmark)

    Briet, Philippe; Cornean, Horia; Savoie, Baptiste

    2012-01-01

    We present a rigorous mathematical treatment of the zero-field orbital magnetic susceptibility of a non-interacting Bloch electron gas, at fixed temperature and density, for both metals and semiconductors/insulators. In particular, we obtain the Landau-Peierls formula in the low temperature...

  2. Biochemical composition and caloric content in the sand whiting Sillago sihama (Forsskal), from Zuari Estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Shamsan, E.F.; Ansari, Z.A.

    -44. Jafri, A. K. 1969. Seasonal changes in the biochemical composition of the freshwater cat fish Wallagoni attu (Bloch). Hydrobiologia Acta. 33(3&4): 497-505. Jayasree, V., A. H. Parulekar, A.H., S. Wahidulla, S. and Kamat, S.Y. 1994. Seasonal changes...

  3. Étude de quelques paramètres de la reproduction de Coryphaena ...

    African Journals Online (AJOL)

    Mullus surmuletus (poisson Mullidae) dans le Nord du golfe de Gascogne : Reproducteurs, larves et juvéniles. Thèse de Doctorat, Université de Bretagne. Occidentale, 177 p. Rey JC, Alot E, Ramos A. 1984. Synopsis biológica del bonito, Sardasarda (Bloch) del. Mediterráneo y Atlántico. Este. Collect. Vol. Sci. Pap. ICCAT,.

  4. Intentionality, morality, and the incest taboo in Madagascar

    Directory of Open Access Journals (Sweden)

    Paulo eSousa

    2016-04-01

    Full Text Available In a recent article (Astuti & Bloch, 2015, cognitive anthropologists Rita Astuti and Maurice Bloch claim that the Malagasy are ambivalent as to whether considerations of intentionality are relevant to moral judgments concerning incest and its presumed catastrophic consequences: when making moral judgments about those who commit incest, the Malagasy take into account whether the incest is intentional or not, but, when making moral judgments relating to incest’s catastrophic consequences, they do not take intentionality into account. Astuti & Bloch explain the irrelevance of intentionality in terms of incest entailing such a fundamental attack on the transcendental social order that the Malagasy become dumbfounded and leave aside considerations of intentionality. Finally, they claim that a similar dumbfound reaction is what is involved in the moral dumbfounding concerning incest that social psychologist Jonathan Haidt has found in the US. In this paper, we argue that (i Astuti & Bloch are unclear about many aspects of their claims (in particular, about the moral judgments at stake, (ii they do not provide sufficient evidence that considerations of intentionality are deemed irrelevant to moral judgments relating to incest’s presumed catastrophic consequences (and hence for the claim that the Malagasy are ambivalent, (iii their hypothesis that conceiving of incest as an attack on the transcendental social renders considerations of intentionality irrelevant lacks coherence, and (iv the extension of their explanatory account to the moral dumfounding of American students in Haidt’s well-known scenario of intentional incest is unwarranted.

  5. The Faraday effect revisited: General theory

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    2006-01-01

    of the strength of the magnetic field B. Then the linear term in B of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in B of the conductivity tensor is expressed in terms of zero magnetic field Bloch...

  6. Using Gait Dynamics to Estimate Load from a Body-Worn Accelerometer

    Science.gov (United States)

    2016-02-05

    Hidalgo Ltd., Cambridge, UK) physiological status monitor, positioned on the left side of the chest below the armpit. The Equivital EQ-02...Salisbury, E., & Paydarfar, D. (2011, November). Using physiological signals to predict apnea in preterm infants. In Signals, Systems and Computers...Indic, P., Bloch- Salisbury, E., & Paydarfar, D. (2013, May). Individualized apnea prediction in preterm infants using cardio-respiratory and movement

  7. Tools and methods for teaching magnetic resonance concepts and techniques

    DEFF Research Database (Denmark)

    Hanson, L.G.

    2012-01-01

    and MRI education. After a few minutes of use, any user with minimal experience of magnetism will be able to explain the basic magnetic resonance principle. A second piece of software, the Bloch Simulator, aims much further, as it can be used to demonstrate and explore a wide range of phenomena including...

  8. asking questions for higher order thinking in visual literacy

    African Journals Online (AJOL)

    ground of learners, lack of resources, poor teacher pedagogical content knowledge, lack of professional collaborative practices and poor instructional leadership (Christie,. 1998, 2008; Bloch, 2009) contribute to the literacy and education crisis. However, drawing on evidence from my role as quality assurer of a Grade 12 ...

  9. Quantum kinetic theory of the chiral anomaly

    Science.gov (United States)

    Sekine, Akihiko; Culcer, Dimitrie; MacDonald, Allan H.

    2017-12-01

    We present a general quantum kinetic theory of low-field magnetotransport in weakly disordered crystals that accounts fully for the interplay between electric-field-induced interband coherence, Bloch-state scattering, and an external magnetic field. The quantum kinetic equation we derive for the Bloch-state density matrix naturally incorporates the momentum-space Berry phase effects whose influence on Bloch-state wave-packet dynamics is normally incorporated into transport theory in an ad hoc manner. The Berry phase correction to the momentum-space density of states in the presence of an external magnetic field implied by semiclassical wave-packet dynamics is captured by our theory as an intrinsic density-matrix response to a magnetic field. We propose a simple and general procedure for expanding the linear response of the Bloch-state density matrix to an electric field in powers of magnetic field. As an illustration, we apply our theory to magnetotransport in Weyl semimetals. We show that the chiral anomaly (positive magnetoconductivity quadratic in magnetic field) that appears when separate Fermi surface pockets surround distinct Weyl points survives only when intervalley scattering is very weak compared to intravalley scattering.

  10. Paavo Järvi salvestis on Grammy nominent

    Index Scriptorium Estoniae

    2005-01-01

    Prantsuse Raadio Filharmooniaorkester Paavo Järvi dirigeerimisel ning norra tshellomängija Truls Mork kandideerivad tänavu süvamuusika kategoorias ning sümfooniaorkestri saatel esineva parima solisti alajaotuses plaadiga "Schumann: Cello Concerto; Bloch: Schelomo" USA muusikaauhinnale Grammy

  11. A Proposed Curriculum on Death and Dying for the Allied Health Student.

    Science.gov (United States)

    Dietrich, Marie C.

    1980-01-01

    This article summarizes the existing curricular models on death education for health professions students. A proposed course design for allied health professions students modified from Bloch's medical education objectives for a thanatology course is presented. The development of listening skills is given special emphasis. (Author/CT)

  12. Intentionality, Morality, and the Incest Taboo in Madagascar

    Science.gov (United States)

    Sousa, Paulo; Swiney, Lauren

    2016-01-01

    In a recent article (Astuti and Bloch, 2015), cognitive anthropologists Astuti and Bloch claim that the Malagasy are ambivalent as to whether considerations of intentionality are relevant to moral judgments concerning incest and its presumed catastrophic consequences: when making moral judgments about those who commit incest, the Malagasy take into account whether the incest is intentional or not, but, when making moral judgments relating to incest’s catastrophic consequences, they do not take intentionality into account. Astuti and Bloch explain the irrelevance of intentionality in terms of incest entailing such a fundamental attack on the transcendental social order that the Malagasy become dumbfounded and leave aside considerations of intentionality. Finally, they claim that a similar dumbfound reaction is what is involved in the moral dumbfounding concerning incest that social psychologist Jonathan Haidt has found in the US. In this article, we argue that (i) Astuti and Bloch are unclear about many aspects of their claims (in particular, about the moral judgments at stake), (ii) they do not provide sufficient evidence that considerations of intentionality are deemed irrelevant to moral judgments relating to incest’s presumed catastrophic consequences (and hence for the claim that the Malagasy are ambivalent), (iii) their hypothesis that conceiving of incest as an attack on the transcendental social renders considerations of intentionality irrelevant lacks coherence, and (iv) the extension of their explanatory account to the moral dumfounding of American students in Haidt’s well-known scenario of intentional incest is unwarranted. PMID:27092099

  13. IRAKI NEW.pmd

    African Journals Online (AJOL)

    Administrator

    their verbal facility and flowery expression. In other words, mastery of language was associated with great intelligence and wisdom, the very antechamber of power. Leaders were expected to be eloquent and verse in culture since language summed up a people's history and value systems (Bloch 1975 cited in Gal (1989).

  14. The multiplication operators on some analytic function spaces of the ...

    Indian Academy of Sciences (India)

    We give equivalent definitions of the multipliers of the space of functions of bounded mean oscillation, the Bloch space and their logarithmic counterparts. Author Affiliations. Benoît F Sehba1. African Institute of Mathematical Sciences, 6 Melrose Road, Muizenberg, Cape Town 7945, South Africa. Dates. Manuscript received ...

  15. 08 Ashcroft 03 WEB.pmd

    African Journals Online (AJOL)

    Owner

    2004-03-21

    Bloch,. The Principle of Hope 158). This may seem to be far too exalted a company for the Constitutional Court, but the point is that .... small museums dedicated to those like Mahatma Gandhi who refused to pay a fine in order to ...

  16. Local Unitary Invariants of Quantum States

    Science.gov (United States)

    Cui, Meiyu; Chang, Jingmei; Zhao, Ming-Jing; Huang, Xiaofen; Zhang, Tinggui

    2017-11-01

    We study the equivalence of mixed states under local unitary transformations. First we express quantum states in Bloch representation. Then based on the coefficient matrices, some invariants are constructed. This method and results can be extended to multipartite high dimensional system.

  17. A Review of Group Systems Theory

    Science.gov (United States)

    Connors, Joanie V.; Caple, Richard B.

    2005-01-01

    The ability to see interpersonal and group processes beyond the individual level is an essential skill for group therapists (Crouch, Bloch & Wanlass, 1994; Dies, 1994; Fuhriman & Burlingame, 1994). In addition to interpersonal therapy models (e.g., Sullivan and Yalom), there are a number of systems theory models that offer a broad array of…

  18. Optical transitions and Rabi oscillations in waveguide arrays.

    Science.gov (United States)

    Makris, K G; Christodoulides, D N; Peleg, O; Segev, M; Kip, D

    2008-07-07

    It is theoretically demonstrated that Rabi interband oscillations are possible in waveguide arrays. Such transitions can take place in optical lattices when the unit-cell is periodically modulated along the propagation direction. Under phase-matching conditions, direct power transfer between two Floquet-Bloch modes can occur. In the nonlinear domain, periodic oscillations between two different lattice solitons are also possible.

  19. Clipboard

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    he put his finger into the probe coil of his nuclear induction apparatus (Bloch et al 1946), but although this could be called the first biological NMR experiment it did not provide any biological information apart from confirming that human tissues are not harmed by intense magnetic fields.] It subsequently became clear that ...

  20. Debate, Research on E-Cigarettes Continues

    Science.gov (United States)

    Since they first began to be sold in North America in the mid-2000s, electronic cigarettes have been the subject of intense debate. NCI's Dr. Michele Bloch recently presented an update on some of the issues surrounding e-cigarettes.

  1. On the "Critique of Everyday Life" to "Metaphilosophy": Henri Lefebvre's Philosophical-Political Legacy of the Cultural Revolution

    Science.gov (United States)

    Sünker, Heinz

    2014-01-01

    Henri Lefebvre (1901-91), philosopher and sociologist, is, together with Theodor W. Adorno, Max Horkheimer, Walter Benjamin and Ernst Bloch, one of the most relevant representatives of the first generation in Western Marxism. His engagement with Marxism led him to analyse everyday life in post-war France in order to decipher the possibilities of,…

  2. A mirrorless photonic free-electron laser oscillator

    NARCIS (Netherlands)

    van der Slot, P.J.M.; Strooisma, A.; Denis, T.; Boller, Klaus J.

    2017-01-01

    Photonic crystals have been used to provide fundamental control over the interaction between light and matter, including stimulated emission. For example, in Bloch-mode lasers, the photonic crystal provides field enhancement through reduced group velocity and offers larger mode volumes through

  3. On the unambiguous determination of effective optical properties of periodic metamaterials: a one-dimensional case study

    DEFF Research Database (Denmark)

    Mortensen, Asger; Yan, Min; Sigmund, Ole

    2010-01-01

    We show how branch ambiguities in the extraction of effective parameters is arising as a direct consequence of the underlying Bloch state physics. The mutual importance of the different branches in general depends on the experimental context, and we show how the Fourier spectrum of the field insi...

  4. Unified Approach to Universal Cloning and Phase-Covariant Cloning

    OpenAIRE

    Hu, Jia-Zhong; Yu, Zong-Wen; Wang, Xiang-Bin

    2008-01-01

    We analyze the problem of approximate quantum cloning when the quantum state is between two latitudes on the Bloch's sphere. We present an analytical formula for the optimized 1-to-2 cloning. The formula unifies the universal quantum cloning (UQCM) and the phase covariant quantum cloning.

  5. On spectral properties of periodic polyharmonic matrix operators

    Indian Academy of Sciences (India)

    We consider a matrix operator = (-) + in , where ≥ 2, ≥ 1, 4 > + 1, and is the operator of multiplication by a periodic in matrix (). We study spectral properties of in the high energy region. Asymptotic formulae for Bloch eigenvalues and the corresponding spectral projections are constructed.

  6. Investigations into homogenization of electromagnetic metamaterials

    DEFF Research Database (Denmark)

    Clausen, Niels Christian Jerichau

    This dissertation encompasses homogenization methods, with a special interest into their applications to metamaterial homogenization. The first method studied is the Floquet-Bloch method, that is based on the assumption of a material being infinite periodic. Its field can then be expanded in term...

  7. Maximizing opto‐mechanical interaction using topology optimization

    DEFF Research Database (Denmark)

    Gersborg, Allan Roulund; Sigmund, Ole

    2011-01-01

    is performed on a periodic cell and the periodic modeling of the optical and mechanical fields have been carried out using transverse electric Bloch waves and homogenization theory in a plane stress setting, respectively. Two coupling effects are included being the photoelastic effect and the geometric effect...

  8. Fenthion induced toxicity and histopathological changes in gill ...

    African Journals Online (AJOL)

    Tersoo

    2015-06-23

    Jun 23, 2015 ... to the herbicide, glyphosate. Afr. J. Biotechnol. 5:2480-2487. Pandey S, Kumar R, Sharma S, Napure NS, Srivastava SK, Verma MS. (2005). Acute toxicity bioassays of mercuric chloride and malathion on air-breathing fish Channa punctatus (Bloch). Ecotoxicol. Environ. Saf. 61:114-120. Peter JV, Cherian ...

  9. Intentionality, Morality, and the Incest Taboo in Madagascar.

    Science.gov (United States)

    Sousa, Paulo; Swiney, Lauren

    2016-01-01

    In a recent article (Astuti and Bloch, 2015), cognitive anthropologists Astuti and Bloch claim that the Malagasy are ambivalent as to whether considerations of intentionality are relevant to moral judgments concerning incest and its presumed catastrophic consequences: when making moral judgments about those who commit incest, the Malagasy take into account whether the incest is intentional or not, but, when making moral judgments relating to incest's catastrophic consequences, they do not take intentionality into account. Astuti and Bloch explain the irrelevance of intentionality in terms of incest entailing such a fundamental attack on the transcendental social order that the Malagasy become dumbfounded and leave aside considerations of intentionality. Finally, they claim that a similar dumbfound reaction is what is involved in the moral dumbfounding concerning incest that social psychologist Jonathan Haidt has found in the US. In this article, we argue that (i) Astuti and Bloch are unclear about many aspects of their claims (in particular, about the moral judgments at stake), (ii) they do not provide sufficient evidence that considerations of intentionality are deemed irrelevant to moral judgments relating to incest's presumed catastrophic consequences (and hence for the claim that the Malagasy are ambivalent), (iii) their hypothesis that conceiving of incest as an attack on the transcendental social renders considerations of intentionality irrelevant lacks coherence, and (iv) the extension of their explanatory account to the moral dumfounding of American students in Haidt's well-known scenario of intentional incest is unwarranted.

  10. Prevalence of pre-cancerous lesions and cervical cancer in South ...

    African Journals Online (AJOL)

    Prevalence of pre-cancerous lesions and cervical cancer in South Africa - A multicentre study. S Fonn, B Bloch, M Mabina, S Carpenter, H Cronje, C Maise, M Bennun, G du Toit, E de Jonge, I Manana, G Lindeque ...

  11. Biochemical modulation in male specimens of Channa punctatus ...

    African Journals Online (AJOL)

    admin

    Biochemical modulation in male specimens of Channa punctatus (Bloch) under different habitats and seasons. C. P. Singh1, R. N. Ram2, Mohd. Danish2* and .... were analyzed using titrimetric method. (APHA, 1992) and temperature, pH, total dissolved solids and conductivity were measured using electronic digital meter.

  12. RAPD analysis for genetic diversity of two populations of Mystus ...

    African Journals Online (AJOL)

    ) was applied to analyze the genetic variation of the 2 populations of Mystus vittatus (Bloch) of Madhya Pradesh, India. 10 random 10-mer primers were primarily scored in 3 individuals from each of the 2 locations. Five primers, which gave ...

  13. Transverse wave propagation in photonic crystal based on holographic polymer-dispersed liquid crystal.

    Science.gov (United States)

    Fuh, Andy Ying-Guey; Li, Ming Shian; Wu, Shing Trong

    2011-07-04

    This study investigates the transversely propagating waves in a body-centered tetragonal photonic crystal based on a holographic polymer-dispersed liquid crystal film. Rotating the film reveals three different transverse propagating waves. Degeneracy of optical Bloch waves from reciprocal lattice vectors explains their symmetrical distribution.

  14. Comparison of spatial harmonics in infinite and finite Bragg stacks for metamaterial homogenization

    DEFF Research Database (Denmark)

    Clausen, Niels Christian Jerichau; Arslanagic, Samel; Breinbjerg, Olav

    2014-01-01

    Metamaterial homogenization may be based on the dominance of a single Floquet-Bloch spatial harmonic in an infinite periodic structure - with the dominance quantified in terms of the relative magnitude of the associated spatial harmonic Poynting vector. For the corresponding finite structure the ...

  15. Antiviral and antifungal activity of some dermaseptin S4 analogues

    African Journals Online (AJOL)

    ajl yemi

    2011-10-26

    Oct 26, 2011 ... 14(40): 22-25. Brand GD, Leite JR, Silva LP, Albuquerque S, Prates MV, Azevedo RB,. Carregaro V, Silva JS, Sá VC, Brandão RA, Bloch CJr (2002). Dermaseptins from Phyllomedusa oreades and Phyllomedusa distincta. Anti-trypanosoma cruzi activity without cytotoxicity to mammalian cells. J. Biol. Chem.

  16. The Effect of Major Organizational Policy on Employee Attitudes Toward Graduate Degrees

    Science.gov (United States)

    2006-03-01

    management skills development. Human Resource Management, 32(2-3), 325-351. Herzberg , Frederick , Mausner, Bernard, & Snyderman, Barabara Bloch (1959...Moreover, need for achievement from motivation theory ( Herzberg , Mausner, & Snyderman, 1959), which describes people who “set goals that are...employee attitudes (Feldman & Bolino, 2000). More specifically, motivation theory as developed by Herzberg et al. (1959) states that the needs of

  17. Dissipative photonic lattice solitons.

    Science.gov (United States)

    Ultanir, Erdem A; Stegeman, George I; Christodoulides, Demetrios N

    2004-04-15

    We show that discrete dissipative optical lattice solitons are possible in waveguide array configurations that involve periodically patterned semiconductor optical amplifiers and saturable absorbers. The characteristics of these low-power soliton states are investigated, and their propagation constant eigenvalues are mapped on Floquet-Bloch band diagrams. The prospect of observing such low-power dissipative lattice solitons is discussed in detail.

  18. Plasmonic fluorescence enhancement of DBMBF2 monomers and DBMBF2-toluene exciplexes using al-hole arrays

    NARCIS (Netherlands)

    Schmidt, T.M.; Bochenkov, V.E.; Espinoza, J.D.A.; Smits, E.C.P.; Muzafarov, A.M.; Kononevich, Y.N.; Sutherland, D.S.

    2014-01-01

    The optical properties of aluminum hole arrays fabricated via colloidal lithography were investigated. By tuning the hole diameter and hole spacing independently, their influence on the Bloch wave-surface plasmon polariton (BW-SPP) and localized surface plasmon resonances resonances (LSPR) could be

  19. An Early History

    Indian Academy of Sciences (India)

    NMR; basic theory; Bloch equations; spin echoes; Overhauser effect; double resonance; polarizaton transfer; FTNMR; solid state NMR; line narrowing; cross polarization. Author Affiliations. B D Nageswara Rao1. 1269, Walleye Common Fremont, CA 94536, USA. Resonance – Journal of Science Education. Current Issue ...

  20. Proceedings of the Tri-Service Conference on Corrosion Held in Atlantic City, New Jersey on 17-19 October 1989

    Science.gov (United States)

    1989-10-19

    importance of these goals is very evident in a recent report by Dr. Erich Bloch,(3 ) the Director of the National Science Foundation, in which he reviewed...1975. 11. D. Fromme , T. Peterson, G. Ross, and E. Peterson, Condulet Test Report, JAYCOR Report No. JTN-CS-5029, 19 September 1986. 12. L. 0. Hoeft and

  1. The Higgs mass derived from the U(3) Lie group

    DEFF Research Database (Denmark)

    Trinhammer, Ole; Bohr, Henrik; Jensen, Mogens O Stibius

    2015-01-01

    The Higgs mass value is derived from a Hamiltonian on the Lie group U(3) where we relate strong and electroweak energy scales. The baryon states of nucleon and delta resonances originate in specific Bloch wave degrees of freedom coupled to a Higgs mechanism which also gives rise to the usual gauge...

  2. Si3N4 grated waveguide optical cavity based sensors for bulk-index concentration, label-free protein, and mechano-optical gas sensing

    NARCIS (Netherlands)

    Pham Van So, P.V.S.; Dijkstra, Mindert; Hollink, Anton; de Ridder, R.M.; Pollnau, Markus; Hoekstra, Hugo

    A grated waveguide (GWG), which is a waveguide with a finite-length grated section, acts as an optical resonator, showing sharp fringes in the transmission spectrum near the stop-band edges of the grating. These oscillations are due to Fabry-Perot resonances of Bloch modes propagating in the cavity

  3. A Comparison of Implications in Orthomodular Quantum Logic—Morphological Analysis of Quantum Logic

    Directory of Open Access Journals (Sweden)

    Mitsuhiko Fujio

    2012-01-01

    Full Text Available Morphological operators are generalized to lattices as adjunction pairs (Serra, 1984; Ronse, 1990; Heijmans and Ronse, 1990; Heijmans, 1994. In particular, morphology for set lattices is applied to analyze logics through Kripke semantics (Bloch, 2002; Fujio and Bloch, 2004; Fujio, 2006. For example, a pair of morphological operators as an adjunction gives rise to a temporalization of normal modal logic (Fujio and Bloch, 2004; Fujio, 2006. Also, constructions of models for intuitionistic logic or linear logics can be described in terms of morphological interior and/or closure operators (Fujio and Bloch, 2004. This shows that morphological analysis can be applied to various non-classical logics. On the other hand, quantum logics are algebraically formalized as orhomodular or modular ortho-complemented lattices (Birkhoff and von Neumann, 1936; Maeda, 1980; Chiara and Giuntini, 2002, and shown to allow Kripke semantics (Chiara and Giuntini, 2002. This suggests the possibility of morphological analysis for quantum logics. In this article, to show an efficiency of morphological analysis for quantum logic, we consider the implication problem in quantum logics (Chiara and Giuntini, 2002. We will give a comparison of the 5 polynomial implication connectives available in quantum logics.

  4. Seaworthy Quantum Key Distribution Design and Validation (SEAKEY)

    Science.gov (United States)

    2015-08-07

    34 New Journal of Physics 13, 013003 (2011). [Scarani et al.] Valerio Scarani, Helle Bechmann-Pasquinucci, Nicolas J. Cerf , Miloslav Dušek, Norbert...Matthieu Bloch, Ra_ul Garc__a-Patr_on, Simon Fossier, Evgueni Karpov, Eleni Diamanti, Thierry Debuisschert, Nicolas J. Cerf , Rosa Tualle-Brouri, Steven

  5. Marine Science

    African Journals Online (AJOL)

    alike (Thresher, 1982; Nelson, 2006). The emperor angelfish, P. imperator Bloch, 1787, is among the most spectacularly colored and broadly recognized spe- cies of coral reef-associated fishes. Globally, the fam- ily comprises about 25% in volume of the estimated. 1472 aquarium species traded annually (Sadovy, 1992;.

  6. Browse Title Index

    African Journals Online (AJOL)

    Items 301 - 350 of 3974 ... A Garrib, N Stoops, A McKenzie, L Dlamini, T Govender, D Rohde, K Herbst. Vol 79, No 4 (1991), An evaluation of the national ... Vol 68, No 14 (1983), An evaluation of treatment modalities in cervical intra-epithelial neoplasia, Abstract PDF. J. Atad, B Bloch. Vol 86, No 7 (1996), An evaluative study of ...

  7. 7 Length-weight relationship

    African Journals Online (AJOL)

    Administrator

    The food and feeding habits of most commercially important marine fish species in Ghana had not been studied. The aim of the paper was to study the diet spectrum of two coastal fishes of Ghana; Galeoides decadactylus. (Polynemidae) Bloch, 1795 ... West African Journal of Applied Ecology, v. , 2013 ol. 21 (1) percentage ...

  8. Alien fish species in upper Sakarya River and their distribution ...

    African Journals Online (AJOL)

    However, the fact that the flood plains have been reclaimed, excessive hunting, destruction of the ecologic balance and invasion of the area by the alien fish species threatens the fish stocks in Sakarya River. In this study, we aimed to determine the dispersion area of Carassius gibelio (Bloch, 1782), Oreochromis niloticus ...

  9. CERN's 25th Anniversary

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    A ceremony in the Main Auditorium on 23 June 1979 to mark the 25th Anniversary of CERN. A photo of the five Director-Generals of CERN, from left to right: John Adams, Willi Jentschke, Felix Bloch, Viki Weisskopf and Leon van Hove.

  10. Data systems and computer science space data systems: Onboard memory and storage

    Science.gov (United States)

    Shull, Tom

    1991-01-01

    The topics are presented in viewgraph form and include the following: technical objectives; technology challenges; state-of-the-art assessment; mass storage comparison; SODR drive and system concepts; program description; vertical Bloch line (VBL) device concept; relationship to external programs; and backup charts for memory and storage.

  11. Physical education, sport and recreation: A triad pedagogy of hope ...

    African Journals Online (AJOL)

    Bloch (2009, 58), a previous advocate of Outcomes-based Education (OBE), states that schooling in SA is a national disaster. Quality holistic education that includes Physical Education (PE) and school sport should be the focal point of progress in developing countries. However, PE is worldwide in a political crisis and the ...

  12. Floquet projections of a Gaussian Wigner function in a Kronig-Penney potential

    Energy Technology Data Exchange (ETDEWEB)

    Maccari, L; Demeio, L [Dipartimento di Scienze Matematiche, Via Brecce Bianche, Universita Politecnica delle Marche, 60131 Ancona (Italy); Bordone, P, E-mail: maccari@dipmat.univpm.i [Physics Department, University of Modena and Reggio Emilia, Via Campi 213/A, I-41025 Modena (Italy)

    2009-11-15

    In this contribution, we apply the multiband model developed in [1] to a Kronig-Penney potential and calculate the Floquet projections of a Gaussian Wigner function in phase space. The Bloch functions are calculated numerically and then used in the expressions of the Wigner projections.

  13. Les innocents et les coupables; Essai d'exégese

    NARCIS (Netherlands)

    Gadourek-Backer, Johanna Carina Augusta

    1963-01-01

    Apres la publication des nouvelles, Camus consacra une grande partie de ses loisirs a la documentation requise pour les Reflexions sur la guillotine. Elles parurent en 1957, avec des contributions d'Arthur Koestler et de M. Bloch, dans un volume intitulé Réflexions sur la peine capitale. Le livre ne

  14. Temperature dependence of ferromagnetic resonance measurements in nanostructured line arrays

    Directory of Open Access Journals (Sweden)

    Raposo V.

    2014-07-01

    Full Text Available We report the effect of temperature on the ferromagnetic resonance (FMR spectra of nanostructured line arrays. Different temperature dependences are observed for permalloy an nickel based samples. The qualitative features of the temperature dependence of the resonance field and linewidth can be described by the usual expression of slow relaxing linewidth mechanism and Bloch equation.

  15. Depot Medroxyprogesterone Acetate (Depo-Provlera) as a Contrac ...

    African Journals Online (AJOL)

    Depot Medroxyprogesterone Acetate (Depo-Provlera) as a Contrac·eptive Preparation. Basil Bloch. Abstract. Experience with depot medroxyprogesterone acetate as a contraceptive preparation in 7 335 patients for a total of 38 714 months over a 3-year period is described. The discontinuation rate was 18.3% and the ...

  16. Quantum Phases and Collective Excitations of a Spin-Orbit-Coupled Bose-Einstein Condensate in a One-Dimensional Optical Lattice

    Science.gov (United States)

    Martone, G. I.

    2017-12-01

    The ground state of a spin-orbit-coupled Bose gas in a one-dimensional optical lattice is known to exhibit a mixed regime, where the condensate wave function is given by a superposition of multiple Bloch-wave components, and an unmixed one, in which the atoms occupy a single Bloch state. The unmixed regime features two unpolarized Bloch-wave phases, having quasimomentum at the center or at the edge of the first Brillouin zone, and a polarized Bloch-wave phase at intermediate quasimomenta. By calculating the critical values of the Raman coupling and of the lattice strength at the transitions among the various phases, we show the existence of a tricritical point where the mixed, the polarized and the edge-quasimomentum phases meet, and whose appearance is a consequence of the spin-dependent interaction. Furthermore, we evaluate the excitation spectrum in the unmixed regime and we characterize the behavior of the phonon and the roton modes, pointing out the instabilities occurring when a phase transition is approached.

  17. Q-derivatives, coherent states and squeezing

    Science.gov (United States)

    Celeghini, E.; Demartino, S.; Desiena, S.; Rasetti, M.; Vitiello, G.

    1994-01-01

    We show that the q-deformation of the Weyl-Heisenberg (q-WH) algebra naturally arises in discretized systems, coherent states, squeezed states and systems with periodic potential on the lattice. We incorporate the q-WH algebra into the theory of (entire) analytical functions, with applications to theta and Bloch functions.

  18. Page 1 1216 C S Sundar 2. Positron annihilation spectroscopy The ...

    Indian Academy of Sciences (India)

    ... potential of ions and electrons exists in a periodic Bloch state. Due to strong Coulomb repulsion from the positive- ion cores, the positron density distribution has a maximum in the interstitial regions y n. SAMPLE .28 M W t RANGE Nu so FET Me m EECTRON to ENS TY). OOPPER BROANNG. (Elect Ron MoeNTUM) t ar.

  19. Exotic galilean symmetry, non-commutativity & the Hall effect

    OpenAIRE

    Horvathy, P.

    2005-01-01

    The ``exotic'' particle model associated with the two-parameter central extension of the planar Galilei group can be used to derive the ground states of the Fractional Quantum Hall Effect. Similar equations arise for a semiclassical Bloch electron. Exotic Galilean symmetry is also be shared by Chern-Simons field theory of the Moyal type.

  20. Umesh V Waghmare | Speakers | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    These ideas apply quite well to dynamical structure of a crystal, as described by the dispersion of its phonons or vibrational waves. The speakers group has shown an interesting relationship between Wannier functions and non-Abelian Berry phases of Bloch electrons, which is centrally relevant to the nontrivial electronic ...

  1. Incontinentia pigmenti

    Directory of Open Access Journals (Sweden)

    Hegde Sundeep

    2006-05-01

    Full Text Available Incontinentia pigmenti or Bloch-Sulzberger syndrome, is a rare X linked dominant disorder with characteristic skin, hair, eye, dental and neurological abnormalities commonly affecting females. This article reports the clinical features and management of a 11 year old girl diagnosed with Incontinentia pigmenti.

  2. Küünarnukk purustas 1,7 miljardit maksva maali / Aadu Hiietamm

    Index Scriptorium Estoniae

    Hiietamm, Aadu, 1954-

    2006-01-01

    Kunstikoguja Steve Wynn lõhkus Las Vegases kogemata Picasso maali "La Reve" ("Unistus"), mille ta oli otsustanud maha müüa 139 miljoni dollari eest. Senine rekordhind - 135 miljonit dollarit - maksti Gustav Klimti portreemaali "Adele Bloch-Bauer I" eest

  3. Infrared phenomena in quantum electrodynamics : I. The physical one-electron states in the infrared region

    NARCIS (Netherlands)

    Haeringen, W. van

    In view of remaining obscurities and difficulties in existing treatments of the infrared divergences in quantum electrodynamics this problem has been considered anew. The approximate model introduced in 1937 by Bloch and Nordsieck is rediscussed. It is explicitly shown to be a good substitute for

  4. An active learning approach to education in MRI technology for the biomedical engineering curriculum

    DEFF Research Database (Denmark)

    Hanson, L.G.

    (literally), since arm motions can to a limited extent be used to illustrate nuclear dynamics. Many students find this confusing, however, and students who do not grasp the meaning during lectures, are left in a bad position. For this reason, educational software was developed over the last decade (the Bloch...

  5. The Faraday effect revisited

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2009-01-01

    This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...

  6. In 1939, he became a naturalized citizen of the United States. Also ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Felix Bloch (1905-1983). Anil Kumar. Article-in-a-Box Volume 20 Issue 11 November 2015 pp 956-958. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/11/0956-0958. Author Affiliations.

  7. Dynamic analysis of atomic magnetometer and co-magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shihu, E-mail: 65980623@qq.com; Yu, Linke; Wang, Wei

    2016-03-01

    Some unsteady-state solutions of Bloch equation which well-describe the behavior of a magnetometer are obtained. These solutions are in accord with the experimental result of alkali-metal magnetometer and co-magnetometer gyroscope. Many interesting phenomena can be also achieved via the solutions. First, the measuring direction of a magnetometer changes with the variation of external magnetic field along z axis. And it could be used for measuring high frequency magnetic field. Then it can be extended that the co-magnetometer without compensated field can get better performance than simple atomic magnetometer due to the effect of polarized noble gas. Finally, we discussed the limits (bandwidth and so on) of atomic magnetometer and co-magnetometer with the Bloch equation of spins. These phenomena, which have not been mentioned before, may contribute to the development of atomic magnetometer and co-magnetometer gyroscope.

  8. The role of electron capture and energy exchange of positively charged particles passing through matter

    CERN Document Server

    Ulmer, W

    2011-01-01

    The conventional treatment of the Bethe-Bloch equation for protons accounts for electron capture at the end of the projectile track by the small Barkas correction. This is only a possible way for protons, whereas for light and heavier charged nuclei the exchange of energy and charge along the track has to be accounted for by regarding the projectile charge q as a function of the residual energy. This leads to a significant modification of the Bethe-Bloch equation, otherwise the range in a medium is incorrectly determined. The LET in the Bragg peak domain and distal end is significantly influenced by the electron capture. A rather significant result is that in the domain of the Bragg peak the superiority of carbon ions is reduced compared to protons.

  9. Integridad y desprecio. Motivos básicos de una concepción de la moral desde la teoría del reconocimiento

    Directory of Open Access Journals (Sweden)

    Hünneth, Axel

    1992-05-01

    Full Text Available Not available.

    Si se admite con Emst Bloch que la completa integridad del hombre, su dignidad, sólo se alcanza estableciendo una adecuada protección ante los distintos modos de ofensa y de desprecio personal, entonces eso significa a la inversa que la integridad de la persona humana depende constitutivamente de la experiencia de reconocimiento intersubjetivo. El presente texto quiere aclarar esa conexión premisa propia de una teoría normativa del reconocimiento recíproco, entre desprecio e integridad humana que Bloch sugirió pero no desarrolló, para así poder introducir una tesis fuerte de sociología moral: la experiencia del desprecio personal representa un impulso moral en el proceso de desarrollo de la sociedad, pues el progreso moral es el resultado de la lucha por el reconocimiento.

  10. Rabi oscillations of surface plasmon polaritons in graphene-pair arrays.

    Science.gov (United States)

    Wang, Feng; Qin, Chengzhi; Wang, Bing; Ke, Shaolin; Long, Hua; Wang, Kai; Lu, Peixiang

    2015-11-30

    We investigate the Bloch mode conversion of surface plasmon polaritons in a periodic array of graphene pairs with each consisting of two separated parallel graphene sheets. The employment of graphene pair as a unit cell in the array yields two Bloch modes belonging to different bands. By periodically modulating the permittivity of dielectrics between graphene along the propagation direction, the interband transitions occur and the modes will alternatively couple to each other, similar to traditional Rabi oscillations in quantum systems. The indirect Rabi oscillations can also be observed through introducing transverse modulation momentum. The period of Rabi oscillations can be optimized by taking advantage of the flexible tunability of graphene. The study suggests that the structure have applications in optical switches and mode converters operating on deep-subwavelength scale.

  11. Tunneling dynamics of Bose—Einstein condensates with higher-order interactions in optical lattice

    Science.gov (United States)

    Tie, Lu; Xue, Ju-Kui

    2011-12-01

    The nonlinear Landau—Zener tunneling and nonlinear Rabi oscillations of Bose—Einstein condensate (BEC) with higher-order atomic interaction between the Bloch bands in an accelerating optical lattice are discussed. Within the two-level model, the tunneling probability of BEC with higher-order atomic interaction between Bloch bands is obtained. We finds that the tunneling rate is closely related to the higher-order atomic interaction. Furthermore, the nonlinear Rabi oscillations of BEC with higher-order atomic interaction between the bands are discussed by imposing a periodic modulation on the level bias. Analytical expressions of the critical higher-order atomic interaction for suppressing/enhancing the Rabi oscillations are obtained. It is shown that the critical value strongly depends on the modulation parameters (i.e., the modulation amplitude and frequency) and the strength of periodic potential.

  12. Effective Zeeman splitting in bent lateral heterojunctions of graphene and hexagonal boron nitride: A new mechanism towards half-metallicity

    Science.gov (United States)

    Yue, Ling; Seifert, Gotthard; Chang, Kai; Zhang, Dong-Bo

    2017-11-01

    Low-dimensional half-metallic (HM) systems are invaluable for future spintronics. Yet a definitive experimental demonstration of HM characteristic in two-dimensional (2D) materials remains elusive. Here, we reveal that in recently synthesized graphene/hexagonal boron nitride (G /h BN ) lateral heterojunctions, pronounced HM can be achieved by applying an in-plane bending. We demonstrate with generalized Bloch theorem that bending has strong influence on interfacial spin states, mimicking the Zeeman effect, which consequently leads to the desired HM phase with a sizable HM gap and excellent magnetic stability. Given recent experimental advances in fabrication of G /h BN heterostructures, this strain-driven HM phase may be practically accessible. The generalized Bloch theorem coupled with self-consistent charge density-functional tight binding is useful to model 2D structures under fundamental deformations, thus may boost the study of strain tunable electronic property of low-dimensional materials with inhomogeneous strain patterns.

  13. Optimal Decay of Wannier functions in Chern and Quantum Hall Insulators

    Science.gov (United States)

    Monaco, Domenico; Panati, Gianluca; Pisante, Adriano; Teufel, Stefan

    2018-01-01

    We investigate the localization properties of independent electrons in a periodic background, possibly including a periodic magnetic field, as e. g. in Chern insulators and in quantum Hall systems. Since, generically, the spectrum of the Hamiltonian is absolutely continuous, localization is characterized by the decay, as {|x| → ∞} , of the composite (magnetic) Wannier functions associated to the Bloch bands below the Fermi energy, which is supposed to be in a spectral gap. We prove the validity of a localization dichotomy in the following sense: either there exist exponentially localized composite Wannier functions, and correspondingly the system is in a trivial topological phase with vanishing Hall conductivity, or the decay of any composite Wannier function is such that the expectation value of the squared position operator, or equivalently of the Marzari-Vanderbilt localization functional, is {+ ∞} . In the latter case, the Bloch bundle is topologically non-trivial, and one expects a non-zero Hall conductivity.

  14. Composite right/left-handed coplanar waveguide band-pass filter using capacitively-coupled zeroth-order resonators

    Science.gov (United States)

    Li, C.; Liu, K.-Y.; Li, F.

    2007-05-01

    Design and performance of a coplanar waveguide (CPW) bandpass filter (BPF) using composite right/left-handed (CRLH) zeroth-order resonators have been studied. The unit cell of the CRLH CPW consists of a series interdigital capacitor and two shunt stub inductors embedded between two sections of CPWs. The Bloch analysis is applied based on the S parameters to derive the characteristics of the eigen modes (Bloch modes), from which the right/left-handed frequency band and the zeroth-order resonant frequency are clearly determined. Then, the susceptance slope parameter of the resonator is extracted and the admittance (J-) inverters are introduced to synthesize a capacitively coupled CPW BPF. The measured performance agrees with the simulated one. They show that the size of the filter is greatly reduced (more than 60%) when compared to a conventional structure.

  15. Phase transitions in thick branes endorsed by entropic information

    Directory of Open Access Journals (Sweden)

    W.T. Cruz

    2017-09-01

    Full Text Available The so-called configurational entropy (CE framework has proved to be an efficient instrument to study nonlinear scalar field models featuring solutions with spatially-localised energy, since its proposal by Gleiser and Stamapoulos. Therefore, in this work, we apply this new physical quantity in order to investigate the properties of degenerate Bloch branes. We show that it is possible to construct a configurational entropy measure in functional space from the field configurations, where a complete set of exact solutions for the model studied displays both double and single-kink configurations. Our study shows a rich internal structure of the configurations, where we observe that the field configurations undergo a quick phase transition, which is endorsed by information entropy. Furthermore, the Bloch configurational entropy is employed to demonstrate a high organisational degree in the structure of the configurations of the system, stating that there is a best ordering for the solutions.

  16. Evaluation of Metabolic Enzymes in Response to Excel Mera 71, a Glyphosate-Based Herbicide, and Recovery Pattern in Freshwater Teleostean Fishes

    Science.gov (United States)

    Samanta, Palas; Pal, Sandipan; Mukherjee, Aloke Kumar; Ghosh, Apurba Ratan

    2014-01-01

    Metabolic enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated in Indian teleostean fishes, namely, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch), for an exposure to 30 days of Excel Mera 71 (17.2 mg/L), a glyphosate formulation, and subsequent depuration under Liv.52, a plant extract at a dose of 187.5 mg/d/250 L for the same period in the same tissues under laboratory condition. ALT activity was significantly increased (P  ALT > ALP, in A. testudineus, while H. fossilis showed the following trend: ALT > AST > ALP. Therefore, these parameters could be used as indicators of herbicidal pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern. PMID:25013782

  17. Transitionless driving on adiabatic search algorithm

    Science.gov (United States)

    Oh, Sangchul; Kais, Sabre

    2014-12-01

    We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.

  18. Frequency conversion induced by time-space modulated media

    Science.gov (United States)

    Yi, Kaijun; Collet, Manuel; Karkar, Sami

    2017-09-01

    Time-space modulated media are realized by periodically modulating parameters of the media in both time and space. In this paper, we study frequency conversion induced by time-space modulated media. Two types of frequency conversion are theoretically and numerically demonstrated; their underlying mechanisms are explained by considering the unusual properties of Bloch modes. We find that the first type of conversion is induced by energy transmission between different orders of Bloch modes, which can be observed when waves inside time-space modulated media are reflected by boundaries. The second type is caused by the Bragg scattering effect occurring inside time-space modulated media; it can be observed when external waves are reflected by time-space modulated media. The frequency can be up or down converted, and the difference caused by the conversion depends on the modulation frequency, which is tunable. Therefore, these frequency conversion phenomena could be exploited to manipulate waves' frequencies for particular purposes.

  19. Evaluation of Metabolic Enzymes in Response to Excel Mera 71, a Glyphosate-Based Herbicide, and Recovery Pattern in Freshwater Teleostean Fishes

    Directory of Open Access Journals (Sweden)

    Palas Samanta

    2014-01-01

    Full Text Available Metabolic enzymes such as alanine aminotransferase (ALT, aspartate aminotransferase (AST, and alkaline phosphatase (ALP were evaluated in Indian teleostean fishes, namely, Anabas testudineus (Bloch and Heteropneustes fossilis (Bloch, for an exposure to 30 days of Excel Mera 71 (17.2 mg/L, a glyphosate formulation, and subsequent depuration under Liv.52, a plant extract at a dose of 187.5 mg/d/250 L for the same period in the same tissues under laboratory condition. ALT activity was significantly increased (P ALT > ALP, in A. testudineus, while H. fossilis showed the following trend: ALT > AST > ALP. Therefore, these parameters could be used as indicators of herbicidal pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern.

  20. Trapping of light with angular orbital momentum above the light cone

    Directory of Open Access Journals (Sweden)

    E. Bulgakov

    2017-01-01

    Full Text Available We consider bound states in the radiation continuum (BSC above the light cone in an one-dimensional periodic array of dielectric spheres in air. The BSCs are classified by orbital angular momentum m, Bloch wave vector β directed along the array, and polarization. The most simple symmetry protected BSCs have m = 0, β = 0 and occur in a wide range of the radius of spheres and dielectric constant. More sophisticated BSCs with m ̸= 0, β = 0 exist only for a selected radius of the spheres at a fixed dielectric constant. We also show the existence of robust Bloch BSCs with β ̸=0, m = 0. The BSCs with m = 0 can be easily detected by the collapse of Fano resonance in scattering of a plane wave. In response to a plane wave with circular polarization the BSCs with m ̸= 0 give rise to Poynting vector spiralling around the array.

  1. Phase transitions in thick branes endorsed by entropic information

    Science.gov (United States)

    Cruz, W. T.; Dantas, D. M.; Correa, R. A. C.; Almeida, C. A. S.

    2017-09-01

    The so-called configurational entropy (CE) framework has proved to be an efficient instrument to study nonlinear scalar field models featuring solutions with spatially-localised energy, since its proposal by Gleiser and Stamapoulos. Therefore, in this work, we apply this new physical quantity in order to investigate the properties of degenerate Bloch branes. We show that it is possible to construct a configurational entropy measure in functional space from the field configurations, where a complete set of exact solutions for the model studied displays both double and single-kink configurations. Our study shows a rich internal structure of the configurations, where we observe that the field configurations undergo a quick phase transition, which is endorsed by information entropy. Furthermore, the Bloch configurational entropy is employed to demonstrate a high organisational degree in the structure of the configurations of the system, stating that there is a best ordering for the solutions.

  2. Wave propagation phenomena in metamaterials for retrieving of effective parameters

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Ha, S.

    2011-01-01

    into account propagation of eigen-waves in multilayered structures (thicknesses 10-100 unit cells). Thus, the question of pa-rameters convergence is naturally resolved in our approach. The method has been tested on complex three-dimensional structures like a split-cube-in-carcass and with circular polarized...... waves on chiral MMs [1, 2]. Elaborating our approach the new method has been established, where the unit-cell volume and face field averaging procedures define wave and input (Bloch) impedances correspond-ingly. The first part of the method involves the extraction of the dominating (fundamental) Bloch...... between constitutive elements, multipoles resonances, multimode or photonic crystal (diffraction type) regimes. There are also technical limitations of the retrieval methods connected with very strong losses, branching ambiguity, convergence to bulk parameters, etc. Moreover, most of the simple methods...

  3. Sorption isotherm measurements by NMR.

    Science.gov (United States)

    Leisen, Johannes; Beckham, Haskell W; Benham, Michael

    2002-01-01

    An experimental setup is described for the automated recording of sorption isotherms by NMR experiments at precisely defined levels of relative humidity (RH). Implementation is demonstrated for a cotton fabric; Bloch decays. T1 and T2* relaxation times were measured at predefined steps of increasing and decreasing relative humidities (RHs) so that a complete isotherm of NMR properties was obtained. Bloch decays were analyzed by fitting to relaxation functions consisting or a slow- and a fast-relaxing component. The fraction of slow-relaxing component was greater than the fraction of sorbed moisture determined from gravimetric sorption data. The excess slow-relaxing component was attributed to plasticized segments of the formerly rigid cellulose matrix. T1 and T2* sorption isotherms exhibit hysteresis similar to gravimetric sorption isotherms. However, correlating RH to moisture content (MC) reveals that both relaxation constants depend only on MC, and not on the history of moisture exposure.

  4. Is biomedical nuclear magnetic resonance limited by a revisitable paradigm in physics?

    Science.gov (United States)

    de Certaines, J D

    2005-12-14

    The history of nuclear magnetic resonance (NMR) can be divided generally into two phases: before the Second World War, molecular beam methods made it possible to detect the whole set of spins. However, these methods were destructive for the sample and had a very low precision. The publications of F. Bloch and E. Purcell in 1946 opened up a second phase for NMR with the study of condensed matter, but at the expense of an enormous loss in theoretical sensitivity. During more than half a century, the method of Bloch and Purcell, based on inductive detection of the NMR signal, has allowed many developments in biomedicine. But, curiously, this severely constraining limitation on sensitivity has not been called into question during this half-century, as if the pioneers of the pre-war period had been forgotten.

  5. An active learning approach to education in MRI technology for the biomedical engineering curriculum

    DEFF Research Database (Denmark)

    Hanson, L.G.

    (literally), since arm motions can to a limited extent be used to illustrate nuclear dynamics. Many students find this confusing, however, and students who do not grasp the meaning during lectures, are left in a bad position. For this reason, educational software was developed over the last decade (the Bloch...... techniques but can also be used for student exercises which may significantly improve the understanding of MRI concepts. The presentation demonstrates software made for the first few minutes of MRI education but focuses mostly on the educational value of the more advanced Bloch Simulator. It is explored how...... sense expressed in the math is in focus. Unfortunately, the nuclear dynamics happen in four dimensions, and are therefore not well suited for illustration on blackboard. 3D movies are more appropriate, but they do not encourage active learning. The typical solution employed by educators is hand waving...

  6. Reactively sputtered epitaxial γ′-Fe4N films: Surface morphology, microstructure, magnetic and electrical transport properties

    KAUST Repository

    Mi, Wenbo

    2013-10-01

    Epitaxial γ′-Fe4N films with (1 0 0) and (1 1 0) orientations have been fabricated by reactive sputtering; these films were characterized by X-ray θ-2θ and φ scans, pole figures and high-resolution transmission electron microscopy. The film surface is very smooth as the film is less than 58 nm thick. The films exhibit soft ferromagnetism, and the saturation magnetization decreases with an increase in temperature, following Bloch\\'s spin wave theory. The films also exhibit a metallic conductance mechanism. Below 30 K, magnetoresistance (MR) is positive and increases linearly with the applied field in the high-field range. In the low-field range, MR increases abruptly. Above 30 K, MR is negative, and its value increases linearly with the applied field.

  7. Asymptotic behavior for a dissipative plate equation in $R^N$ with periodic coefficients

    Directory of Open Access Journals (Sweden)

    Eleni Bisognin

    2008-03-01

    Full Text Available In this work we study the asymptotic behavior of solutions of a dissipative plate equation in $mathbb{R}^N$ with periodic coefficients. We use the Bloch waves decomposition and a convenient Lyapunov function to derive a complete asymptotic expansion of solutions as $to infty$. In a first approximation, we prove that the solutions for the linear model behave as the homogenized heat kernel.

  8. Bibliography of Technical Publications and Papers

    Science.gov (United States)

    1974-07-01

    for single recovery parachute systems. Vol II. Calculation procedures and computer pro- gram. 74-9-ADII, December 1973 (AD 779 528). 61. MURPHY, A. L...tenderness. J. Agric. Food Chem., 21(5): 880-883 (1973). 117, HARRIS, N. E., I. BLOCH, and A. S. HENICK. Method for deter- mining almonds in chocolate candy...and A. W. BAKER. Status of the radappertization of meats. J. Milk & Food Technol., 37: 86-93 (1974). 15 FOOD LABORATORY Journal Articles (continued

  9. From Methodical Battle to Shock and Awe: How to Guard Against the Next Great Idea

    Science.gov (United States)

    2012-05-11

    terre francaise (1935-1939) (Paris: Imprimerie nationale, 1980), 289, quoted in Doughty, Seeds of Disaster, 3. 5 Ibid. 6 Marc Bloch, Strange...Secretary Rumsfeld wanted to recast the military into a leaner force to meet the challenges of the 21st century. Based on briefings on the revolution of...Military Revolution (Cambridge, MA: Cambridge University Press, 2010), 112. Colonel John Boyd was a fighter pilot and Air Force iconoclast famous

  10. Cancer stem cells, the ultimate targets in cancer therapy

    OpenAIRE

    Shabbir A; Esfandyari T; Farassati F

    2018-01-01

    Ahmed Shabbir,1 Tuba Esfandyari,2 Faris Farassati1,3,4 1Midwest Biomedical Research Foundation, Kansas City Veterans Affairs Medical Center, 2Department of Medicine, School of Medicine, The University of Kansas, 3Saint Luke’s Cancer Institute, 4Saint Luke’s Marion Bloch Neuroscience Institute, Saint Luke’s Health System, Kansas City, MO, USAThe concept of cancer stem cells (CSCs) is currently of significant interest due to its important implications in our under...

  11. Cancer stem cells, the ultimate targets in cancer therapy

    OpenAIRE

    Shabbir A; Esfandyari T; Farassati F

    2018-01-01

    Ahmed Shabbir,1 Tuba Esfandyari,2 Faris Farassati1,3,4 1Midwest Biomedical Research Foundation, Kansas City Veterans Affairs Medical Center, 2Department of Medicine, School of Medicine, The University of Kansas, 3Saint Luke’s Cancer Institute, 4Saint Luke’s Marion Bloch Neuroscience Institute, Saint Luke’s Health System, Kansas City, MO, USAThe concept of cancer stem cells (CSCs) is currently of significant interest due to its important implications in our understanding of ...

  12. Clinical Assessment of the Noise Immune Stethoscope aboard a U.S. Navy Carrier

    Science.gov (United States)

    2011-11-01

    HEARTIIX(’G SOt:(’DS AcnuzL1aton’Jt subject diagnosis (drde): V.Jw.lopathy: Al!AR AS MLMR MS Cardiomyopathy : ischemic dilated PR PS MVP T11R VSD...the device to be moderately helpful in making clinical diagnosis and decisions in noisy environments. Small enrollment numbers prohibit definitive...inventor, Rene Laennec, skillfully noted that the sounds of intrathoracic organs can prove valuable for assessment and diagnosis (Bloch, 1993

  13. Superluminal propagation of solitary kinklike waves in amplifying media.

    Science.gov (United States)

    Janowicz, Maciej; Mostowski, Jan

    2006-04-01

    It is shown that solitary-wave, kinklike structures can propagate superluminally in two- and four-level amplifying media with strongly damped oscillations of coherences. This is done by solving analytically the Maxwell-Bloch equations in the kinetic limit. It is also shown that the true wave fronts--unlike the pseudo wave fronts of the kinks--must propagate with velocity c, so that no violation of special relativity is possible. The conditions of experimental verification are discussed.

  14. Eelworms in wild hoofed mammals of Ukraine

    Directory of Open Access Journals (Sweden)

    Y. Dovgyi

    2011-08-01

    Full Text Available Strongylata, Rhabditata and Ascaridata eelworms were found in wild hoofs (roe deers and wild boars in Ukraine. Strongylata are presented by Globocephalus sp., Dictyocaulus viviparous (Bloch, D. еckerti Skrjabin, Muellerius sp., Cystocaulus sp., Protostrongylus sp., Haemonchus contortus Rundolphi, Marshallagia marshalli (Ransom, Nematodirus oiratianus Rajevskaja, Trichostrongylus axei (Cobbold, Bunostomum phlebotomum (Railliet, Oesophagostomum venulosus (Rudolphi, O. dentatm (Rudolphi and Chabertia ovina (Raill.. The helmints Strongyloides papillosus Wedl, S. ransomi Scwartz et Al. and Ascaris suum (Goeze were identified for Rhabditata and Ascaridata.

  15. AUCUN OEIL NE L’A VU. SUR UNE FORCE ÉTRANGE D’AGIR POUR LES CHOSES LOINTAINES D’APRÈS LEVINAS (No eye sees that. On strange power to act in favor of things of distant future according to Levinas

    Directory of Open Access Journals (Sweden)

    Jan Bierhanzl

    2015-06-01

    Full Text Available The topic of our paper is utopia, understood as temporally (and not spatialy invisible, as well as its importance for thinking through what Emmanuel Levinas, inspired by Ernst Bloch, call “work” (« œuvre » in french and what will – as we shall see – have to be distinguished from action in the proper sense of the word.

  16. Slow light based on material and waveguide dispersion

    DEFF Research Database (Denmark)

    Nielsen, Torben Roland; Lavrinenko, Andrei; Mørk, Jesper

    2009-01-01

    We study slow light pulse propagation in a photonic crystal structure consisting of a dispersive and absorptive dielectric material and compare it with the constant wave case. The group index and the trasmission are investigated for the example of an ensemble of semiconductor quantum dots embedde...... in a photonic crystal waveguide by FDTD Maxwell-Bloch simulations. The total group index scales linearly with the material based group index whicle the transmission has a power dependency on the material based absorption coefficient....

  17. EMERGING INFECTIOUS DISEASES. Actions Needed to Address the Challenges of Responding to Zika Virus Disease Outbreaks

    Science.gov (United States)

    2017-05-01

    fever, West Nile, and Japanese encephalitis viruses , among others.9 The virus was first identified in the Zika Forest in Uganda, Africa in 1947, from...notifications of the Zika virus . 15Arboviruses are any of a group of viruses that are transmitted by mosquitoes, ticks, or other arthropods (an animal...in response to antigens such as viruses . 28Anna R. Plourde and Evan M. Bloch, “A Literature Review of Zika Virus ,” Emerging Infectious Diseases

  18. ESR powder line shape calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vitko, J. Jr.; Huddleston, R.E.

    1976-05-01

    A program has been developed for computing the ESR spectrum of a collection of randomly oriented spins subject only to an electronic Zeeman interaction and having a Lorentzian single crystal line shape. Other single crystal line shapes, including numerical solutions of the Bloch equations, can be accommodated with minor modifications. The program differs in several features from those existing elsewhere, thus enabling one to study saturation effects, over-modulation effects, both absorptive and dispersive signals, and second and higher order derivative signals.

  19. Phase-space quantum mechanics study of two identical particles in an external oscillatory potential

    Science.gov (United States)

    Nieto, Luis M.; Gadella, Manuel

    1993-01-01

    This simple example is used to show how the formalism of Moyal works when it is applied to systems of identical particles. The symmetric and antisymmetric Moyal propagators are evaluated for this case; from them, the correct energy levels of energy are obtained, as well as the Wigner functions for the symmetric and antisymmetric states of the two identical particle system. Finally, the solution of the Bloch equation is straightforwardly obtained from the expressions of the Moyal propagators.

  20. Pseudempleurosoma haywardi sp. nov. (Monogenea: Ancyrocephalidae (sensu lato) Bychowsky & Nagibina, 1968): An endoparasite of croakers (Teleostei: Sciaenidae) from Indonesia

    OpenAIRE

    Stefan Theisen; Harry W Palm; Al-Jufaili, Sarah H.; Sonja Kleinertz

    2017-01-01

    An endoparasitic monogenean was identified for the first time from Indonesia. The oesophagus and anterior stomach of the croakers Nibea soldado (Lacépède) and Otolithes ruber (Bloch & Schneider) (n = 35 each) sampled from the South Java coast in May 2011 and Johnius amblycephalus (Bleeker) (n = 2) (all Sciaenidae) from Kedonganan fish market, South Bali coast, in November 2016, were infected with Pseudempleurosoma haywardi sp. nov. Prevalences in the first two croakers were 63% and 46%, respe...