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Sample records for bivalvia mollusca searching

  1. Comparative genomics of vesicomyid clam (Bivalvia: Mollusca chemosynthetic symbionts

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    Girguis Peter R

    2008-12-01

    Full Text Available Abstract Background The Vesicomyidae (Bivalvia: Mollusca are a family of clams that form symbioses with chemosynthetic gamma-proteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a reduced gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. Recently, two vesicomyid symbiont genomes were sequenced, illuminating the possible nutritional contributions of the symbiont to the host and making genome-wide evolutionary analyses possible. Results To examine the genomic evolution of the vesicomyid symbionts, a comparative genomics framework, including the existing genomic data combined with heterologous microarray hybridization results, was used to analyze conserved gene content in four vesicomyid symbiont genomes. These four symbionts were chosen to include a broad phylogenetic sampling of the vesicomyid symbionts and represent distinct chemosynthetic environments: cold seeps and hydrothermal vents. Conclusion The results of this comparative genomics analysis emphasize the importance of the symbionts' chemoautotrophic metabolism within their hosts. The fact that these symbionts appear to be metabolically capable autotrophs underscores the extent to which the host depends on them for nutrition and reveals the key to invertebrate colonization of these challenging environments.

  2. Nervous system development in the Pacific oyster, Crassostrea gigas (Mollusca: Bivalvia).

    Science.gov (United States)

    Yurchenko, Olga V; Skiteva, Olga I; Voronezhskaya, Elena E; Dyachuk, Vyacheslav A

    2018-01-01

    have not been observed previously in molluscs. Finally, we performed a morphology-based comparative analysis of neuronal structures among bivalve, conchiferan, and aculiferan species. We described the development of the nervous system during the larval development in Crassostrea gigas . These data greatly advance the currently limited understanding of neurodevelopment in bivalves and mollusks, which has hampered the generation of a ground pattern reconstruction of the last common ancestor of Mollusca. Our morphological data support phylogenomic data indicating a closer Bivalvia-Gastropoda sister group relationship than the Bivalvia-Scaphopoda (Diasoma) group relationship.

  3. The Histopathology of the Infection of Tilapia rendalli and Hypostomus regani (Osteichthyes by Lasidium Larvae of Anodontites trapesialis (Mollusca, Bivalvia

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    Ângela Teresa Silva-Souza

    2002-04-01

    Full Text Available It is described the histopathology of the infection of Tilapia rendalli (Osteichthyes, Perciformes, Cichlidae and Hypostomus regani (Osteichthyes, Siluriformes, Loricariidae by lasidium larvae of Anodontites trapesialis (Mollusca, Bivalvia, Mycetopodidae. The larvae were encysted within the epidermis of the host, being surrounded by a thin hyaline membrane, 3-6 µm thick, of parasite origin. A proliferative host cell reaction did not occur. The histopathology of the infection shows that the lesions induced by the parasites are minimal. However, the numerous small lesions produced by the release of the larvae may provide optimal conditions for the infection by opportunistic pathogens, namely fungus, which may eventually cause the death of the host.

  4. MOLLUSCA' BIODIVERSITY (GASTROPODA AND BIVALVIA AS A BIO INDICATOR OF QUALITY OF WATER IN THE COASTAL ISLAND OF TUNDA ISLAND, BANTEN

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    Indria Wahyuni

    2017-07-01

    Full Text Available The research has been done on Juli 2017 in the coastal region of Tunda Island. This study aims to determine the Biodiversity of Mollusca (Gastropoda and Bivalvia As Bioindicator of Water Quality In Coastal Area of Tunda Island, Banten. Sampling consists of 2 observation stations, namely the mangrove coastal area (3 transects and the seagrass coastal area (2 transects determined by purposive sampling. The observation of each station is done by using the quadratic transect method with 100 m transect line distance, and in each transect line there are 5 observation plots measuring 1m2 x 1m2. The data analysis includes density, biodiversity, bio-indicators of water quality based on diversity index. Result of research on 5 transect found 45 type Mollusca which represent 2 class, that is Gastropoda class of 29 species Gastropoda joined in 14 Family. As for Bivalvia class found 16 species incorporated in 9 families. The total density of Mollusca is 541.2 ind / m2 which consists of 392.4 ind / m2 for Gastropoda class and 148.8 ind / m2 for Bivalvia class. Mollusca diversity was calculated using the diversity index of Shannon-Wienner (H '. The results of diversity index ranged from 3.1356 - 3.3314 with high category. Bioindicator of aquatic quality using diversity index indicates that the coastal area of Tunda Island belongs to a very mildly polluted category.

  5. Molecular phylogenetic analysis supports a Gondwanan origin of the Hyriidae (Mollusca: Bivalvia: Unionida) and the paraphyly of Australasian taxa.

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    Graf, Daniel L; Jones, Hugh; Geneva, Anthony J; Pfeiffer, John M; Klunzinger, Michael W

    2015-04-01

    The freshwater mussel family Hyriidae (Mollusca: Bivalvia: Unionida) has a disjunct trans-Pacific distribution in Australasia and South America. Previous phylogenetic analyses have estimated the evolutionary relationships of the family and the major infra-familial taxa (Velesunioninae and Hyriinae: Hyridellini in Australia; Hyriinae: Hyriini, Castaliini, and Rhipidodontini in South America), but taxon and character sampling have been too incomplete to support a predictive classification or allow testing of biogeographical hypotheses. We sampled 30 freshwater mussel individuals representing the aforementioned hyriid taxa, as well as outgroup species representing the five other freshwater mussel families and their marine sister group (order Trigoniida). Our ingroup included representatives of all Australian genera. Phylogenetic relationships were estimated from three gene fragments (nuclear 28S, COI and 16S mtDNA) using maximum parsimony, maximum likelihood, and Bayesian inference, and we applied a Bayesian relaxed clock model calibrated with fossil dates to estimate node ages. Our analyses found good support for monophyly of the Hyriidae and the subfamilies and tribes, as well as the paraphyly of the Australasian taxa (Velesunioninae, (Hyridellini, (Rhipidodontini, (Castaliini, Hyriini)))). The Hyriidae was recovered as sister to a clade comprised of all other Recent freshwater mussel families. Our molecular date estimation supported Cretaceous origins of the major hyriid clades, pre-dating the Tertiary isolation of South America from Antarctica/Australia. We hypothesize that early diversification of the Hyriidae was driven by terrestrial barriers on Gondwana rather than marine barriers following disintegration of the super-continent. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Evaluation of uptake and chronic toxicity of virgin polystyrene microbeads in freshwater zebra mussel Dreissena polymorpha (Mollusca: Bivalvia).

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    Magni, Stefano; Gagné, François; André, Chantale; Della Torre, Camilla; Auclair, Joëlle; Hanana, Houda; Parenti, Camilla Carla; Bonasoro, Francesco; Binelli, Andrea

    2018-08-01

    Microplastics (MPs), plastic debris smaller than 5mm, are widely found in both marine and freshwater ecosystems. However, few studies regarding their hazardous effects on inland water organisms, have been conducted. For this reason, the aim of our research was the evaluation of uptake and chronic toxicity of two mixtures (MIXs) of virgin polystyrene microbeads (PMs) of 10μm and 1μm in size (MIX 1, with 5×10 5 of 1μmsizePMs/L and 5×10 5 of 10μmsizePMs/L, and MIX 2 with 2×10 6 of 1μmsizePMs/L and 2×10 6 of 10μmsizePMs/L) on freshwater zebra mussel Dreissena polymorpha (Mollusca: Bivalvia) during 6 exposure days. The PM uptake in the mussel body and hemolymph was assessed using confocal microscopy, while the chronic toxicity of PMs was evaluated on exposed mussels using a comprehensive battery of biomarkers of cellular stress, oxidative damage and neuro- genotoxicity. Confocal microscopy analyses showed that MPs concentrated in the gut lumen of exposed mussels, absorbed and transferred firstly in the tissues and then in the hemolymph. The results revealed that PMs do not produce oxidative stress and genetic damage, with the exception of a significant modulation of catalase and glutathione peroxidase activities in mussels exposed to MIX 1. Regarding neurotoxicity, we observed only a significant increase of dopamine concentration in mussels exposed to both MIXs, suggesting a possible implication of this neurotransmitter in an elimination process of accumulated PMs. This research represents a first study about the evaluation of virgin MP toxicity in zebra mussel and more research is warranted concerning the long term neurological effects of virgin MPs. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

  7. Comparative morphology among representatives of main taxa of Scaphopoda and basal protobranch Bivalvia (Mollusca

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    Luiz Ricardo L. Simone

    2009-01-01

    Full Text Available This study deals with detailed morphology and anatomy of 4 species of Scaphopoda and 5 species of protobranch Bivalvia. Both classes are traditionally grouped in the taxon Diasoma, which has been questioned by different methodologies, such as molecular and developmental. This study is developed under a phylogenetic methodology with the main concern in performing it in an intelligible and testable methodology. The analyzed Scaphopoda species came from the Brazilian coast and belong to the family Dentaliidae [(1 Coccodentalium carduus; (2 Paradentalium disparile] and Gadiliidae; [(3 Polyschides noronhensis, n. sp. from Fernando de Noronha Archipelago; (4 Gadila braziliensis]. These species represent the main branches of the class Scaphopoda. From protobranch bivalves, representatives of the families Solemyidae [(5 Solemya occidentalis, from Florida; S. notialis, n. sp. from S.E. Brazil], Nuculanidae [(6 Propeleda carpentieri from Florida], and Nuculidae [(7 Ennucula puelcha, from south Brazil] are included. These species represent the main branches of the basal Bivalvia. The descriptions on the anatomy of S. occidentalis and of P. carpentieri are published elsewhere. The remaining are included here, for which a complete taxonomical treatment is performed. Beyond these species, representatives of other taxa are operationally included as part of the ingroup (indices are then shared with them, as a procedure to test the morphological monophyly of Diasoma. These taxa are: two lamellibranch bivalves [(8 Barbatia - Arcidae; (9 Serratina - Tellinidae; both published elsewhere;, and Propilidium (10 Patellogastropoda, and (11 Nautilus, basal Cephalopoda, based on basal taxa. The effective outgroups are (12 Neopilina (Monoplacophora and (13 Hanleya (Polyplacophora. The phylogenetic analysis based on morphology revealed that the taxon Diasoma is supported by 14 synapomorphies, and is separated from Cyrtosoma (Gastropoda + Cephalopoda. Although they are not

  8. Molecular phylogeny of pearl oysters and their relatives (Mollusca, Bivalvia, Pterioidea

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    Tëmkin Ilya

    2010-11-01

    Full Text Available Abstract Background The superfamily Pterioidea is a morphologically and ecologically diverse lineage of epifaunal marine bivalves distributed throughout the tropical and subtropical continental shelf regions. This group includes commercially important pearl culture species and model organisms used for medical studies of biomineralization. Recent morphological treatment of selected pterioideans and molecular phylogenetic analyses of higher-level relationships in Bivalvia have challenged the traditional view that pterioidean families are monophyletic. This issue is examined here in light of molecular data sets composed of DNA sequences for nuclear and mitochondrial loci, and a published character data set of anatomical and shell morphological characters. Results The present study is the first comprehensive species-level analysis of the Pterioidea to produce a well-resolved, robust phylogenetic hypothesis for nearly all extant taxa. The data were analyzed for potential biases due to taxon and character sampling, and idiosyncracies of different molecular evolutionary processes. The congruence and contribution of different partitions were quantified, and the sensitivity of clade stability to alignment parameters was explored. Conclusions Four primary conclusions were reached: (1 the results strongly supported the monophyly of the Pterioidea; (2 none of the previously defined families (except for the monotypic Pulvinitidae were monophyletic; (3 the arrangement of the genera was novel and unanticipated, however strongly supported and robust to changes in alignment parameters; and (4 optimizing key morphological characters onto topologies derived from the analysis of molecular data revealed many instances of homoplasy and uncovered synapomorphies for major nodes. Additionally, a complete species-level sampling of the genus Pinctada provided further insights into the on-going controversy regarding the taxonomic identity of major pearl culture species.

  9. Molecular phylogeny of pearl oysters and their relatives (Mollusca, Bivalvia, Pterioidea)

    Science.gov (United States)

    2010-01-01

    Background The superfamily Pterioidea is a morphologically and ecologically diverse lineage of epifaunal marine bivalves distributed throughout the tropical and subtropical continental shelf regions. This group includes commercially important pearl culture species and model organisms used for medical studies of biomineralization. Recent morphological treatment of selected pterioideans and molecular phylogenetic analyses of higher-level relationships in Bivalvia have challenged the traditional view that pterioidean families are monophyletic. This issue is examined here in light of molecular data sets composed of DNA sequences for nuclear and mitochondrial loci, and a published character data set of anatomical and shell morphological characters. Results The present study is the first comprehensive species-level analysis of the Pterioidea to produce a well-resolved, robust phylogenetic hypothesis for nearly all extant taxa. The data were analyzed for potential biases due to taxon and character sampling, and idiosyncracies of different molecular evolutionary processes. The congruence and contribution of different partitions were quantified, and the sensitivity of clade stability to alignment parameters was explored. Conclusions Four primary conclusions were reached: (1) the results strongly supported the monophyly of the Pterioidea; (2) none of the previously defined families (except for the monotypic Pulvinitidae) were monophyletic; (3) the arrangement of the genera was novel and unanticipated, however strongly supported and robust to changes in alignment parameters; and (4) optimizing key morphological characters onto topologies derived from the analysis of molecular data revealed many instances of homoplasy and uncovered synapomorphies for major nodes. Additionally, a complete species-level sampling of the genus Pinctada provided further insights into the on-going controversy regarding the taxonomic identity of major pearl culture species. PMID:21059254

  10. A massive ingression of the alien species Mytilus edulis L. (Bivalvia: Mollusca into the Mediterranean Sea following the Costa Concordia cruise-ship disaster

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    E. CASOLI

    2016-03-01

    Full Text Available The Costa Concordia cruise-ship disaster occurred just off the coast of Italy on January 13th, 2012, and entailed the largest marine salvage operation in history. The salvage employed vessels from different European harbours, providing an unexpected means for transporting alien species into the Mediterranean. In this work we identified mussel species using fragments length polymorphism of a nuclear locus and report the first evidence of the transport of the blue mussel, Mytilus edulis Linnaeus, 1758 (Bivalvia: Mollusca, into the Mediterranean Sea, as a part of the fouling community of the hull of an accommodation barge arrived from a NE Atlantic location in October 2012. Furthermore, we describe the rapid growth of this species, under the ASV Pioneer, until its almost total extinction during the summer of 2013, which left a covering of mussel shells on the underlying Posidonia oceanica (Linnaeus Delile, 1813. meadow. This high mortality rate indicated that M. edulis had been exposed to high stress conditions, probably due to different salinity, temperature, and oligotrophic conditions from its place of origin, and there was no spawning event or known settlement on the nearest infralittoral natural habitats. This event reminds us of how the Mediterranean Sea is constantly under alien-species pressure, due to human activities.

  11. The influence of fish cage culture on δ{sup 13}C and δ{sup 15}N of filter-feeding Bivalvia (Mollusca)

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    Benedito, E.; Takeda, A.M., E-mail: eva@nupelia.uem.br [Universidade Estadual de Maringa (UEM), PR (Brazil). Nucleo de Pesquisas em Limnologia, Ictiologia e Aquicultura; Figueroa, L. [Universidade Estadual de Maringa (UEM), PR (Brazil). Pos-Graduacao em Ecologia de Ambientes Aquaticos Continentais; Manetta, GI. [Universidade Estadual de Maringa (UEM), PR (Brazil). Pos-Graduacao em Biologia Comparada

    2013-11-15

    The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ{sup 13}C and δ{sup 15}N in Corbicula fluminea (Mollusca; Bivalvia) and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP). Samples of specimens of the bivalve filter C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C) for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) isotopic value analysis in a mass spectrometer. There were significant differences in the δ{sup 13}C and δ{sup 15}N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ{sup 13}C and δ{sup 15}N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem. (author)

  12. (Lamark) (Mollusca: Bivalvia)

    African Journals Online (AJOL)

    Figure 2 Mean monthly surface water temperature and salinity values ..... Excluding the effect of the flood, the progression of the .... Growth and metabolism of Mactra lilacea. Abstract ... tolerance and osmoregulation in some estuarine bivalves.

  13. The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae).

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    Vierna, J; Jensen, K T; Martínez-Lage, A; González-Tizón, A M

    2011-08-01

    The linkage between 5S ribosomal DNA and other multigene families has been detected in many eukaryote lineages, but whether it provides any selective advantage remains unclear. In this work, we report the occurrence of linked units of 5S ribosomal DNA (5S rDNA) and U1 small nuclear DNA (U1 snDNA) in 10 razor shell species (Mollusca: Bivalvia: Pharidae) from four different genera. We obtained several clones containing partial or complete repeats of both multigene families in which both types of genes displayed the same orientation. We provide a comprehensive collection of razor shell 5S rDNA clones, both with linked and nonlinked organisation, and the first bivalve U1 snDNA sequences. We predicted the secondary structures and characterised the upstream and downstream conserved elements, including a region at -25 nucleotides from both 5S rDNA and U1 snDNA transcription start sites. The analysis of 5S rDNA showed that some nontranscribed spacers (NTSs) are more closely related to NTSs from other species (and genera) than to NTSs from the species they were retrieved from, suggesting birth-and-death evolution and ancestral polymorphism. Nucleotide conservation within the functional regions suggests the involvement of purifying selection, unequal crossing-overs and gene conversions. Taking into account this and other studies, we discuss the possible mechanisms by which both multigene families could have become linked in the Pharidae lineage. The reason why 5S rDNA is often found linked to other multigene families seems to be the result of stochastic processes within genomes in which its high copy number is determinant.

  14. Pectinoidea (Mollusca: Bivalvia) from Iceland

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    Dijkstra, H.H.; Waren, A.; Gudmundsson, G.

    2009-01-01

    The Icelandic pectinoid fauna is reviewed, based on material from the benthic survey programme BIOICE and 17 species are recorded. Similipecten oskarssoni is proposed as a replacement name for Pecten groenlandicus var. minor Locard, 1898 (Propeamussiidae), which is considered a valid species.

  15. Fauna Europaea: MolluscaBivalvia

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    Rafael Araujo

    2015-07-01

    European freshwater bivalves belong to the Orders Unionoida and Cardiida. All the European unionoids are included in the superfamily Unionoidea, the freshwater mussels or naiads. The European cardiids belong to the following three superfamilies: Cardioidea, Cyrenoidea and Dreissenoidea. Among the Unionoidea there are the most imperilled animal groups on the planet while the Cardioidea includes the cosmopolitan genus Pisidium, the Cyrenoidea the Asiatic clam (Corbicula fluminea and the Dreissenoidea the famous invasive zebra mussel (Dreissena polymorpha. Basic information is summarized on their taxonomy and biology. Tabulations include a complete list of the current estimated families, genera and species.

  16. Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Daniele

    2012-07-01

    The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of Sao Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in Sao Paulo coast are located in the geographical areas 23 Masculine-Ordinal-Indicator 37'S - 45 Degree-Sign 24' W (Caraguatatuba) and 23 Masculine-Ordinal-Indicator 57'S - 46 Masculine-Ordinal-Indicator 20' W (Santos). The collection of organisms

  17. Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Daniele

    2012-07-01

    The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of Sao Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in Sao Paulo coast are located in the geographical areas 23 Masculine-Ordinal-Indicator 37'S - 45 Degree-Sign 24' W (Caraguatatuba) and 23 Masculine-Ordinal-Indicator 57'S - 46 Masculine-Ordinal-Indicator 20' W (Santos). The collection of organisms was performed in all

  18. Comunidad de moluscos asociados al mejillón verde Perna viridis (Mollusca: Bivalvia y sus relaciones tróficas en la costa norte de la Península de Araya, Estado Sucre, Venezuela

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    Sioliz Villafranca

    2006-12-01

    Full Text Available Perna viridis es un bivalvo procedente del Indo-Pacífico que habita en la zona intermareal y ha invadido varios ecosistemas de la costa norte del estado Sucre, Venezuela. Con la finalidad de realizar un estudio sobre las comunidades de moluscos asociadas a esta especie y sus relaciones tróficas, se llevaron a cabo muestreos bimensuales entre octubre/97 y agosto/98, en un banco natural de mejillones a dos metros de profundidad en la costa norte de la península de Araya (10°40’N -48°63’W. Los organismos fueron recolectados delimitando el área con una cuadrícula de 0.25 m². Se identificaron los organismos hasta la categoría de especies utilizando claves específicas para moluscos y bibliográficamente se les determinó categoría trófica.Se capturó un total de 1 235 individuos de P. viridis y asociados a la especie 3 163 especímenes pertenecientes al phylum Mollusca, contenidos en tres clases: Bivalvia,Gastropoda y Polyplacophora. Éstas estuvieron representadas por 50 especies correspondientes a 10 órdenes, 24 familias; para los gasterópodos se contabilizaron 25 especies, para los bivalvos 22 y tres para los poliplacóforos. Del total de las especies, 40% fueron filtradoras, 26% carnívoras, 24% herbívoras y el 10% restante presentó dos categorías.De las filtradoras las más representativas fueron: Perna perna, Musculus lateralis, Crassostrea rhizophorae y Ostrea equestris; en el grupo de los carnívoros dominaron tres especies de la familia Columbellidae:Mitrella lunata, Anachis obesa y Nitidella ocellata y para el grupo de los herbívoros destacaron dos especies de la familia Fisurellidae: Diodora cayenensis y D. minuta. Se registraron dos especies filtradoras-detritívoras, y tres especies herbívoras-filtradoras representantes del género C repidula. El alto porcentaje de filtradores sería un indicativo de que dentro de este sistema probablemente hay una mayor disponibilidad de fracciones alimenticias para este grupo

  19. Genetic Population Structure and Demographic History of the Widespread Common Shipworm Teredo navalis Linnaeus 1758 (Mollusca: Bivalvia: Teredinidae in European Waters Inferred from Mitochondrial COI Sequence Data

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    Ronny Weigelt

    2017-06-01

    Full Text Available The first documented scientific reports of the common marine shipworm Teredo navalis (Bivalvia for Central European waters date back to the time between 1700 and 1730 in the Netherlands. During the following centuries there were several irregular mass occurrences reported for both the North Sea and the Baltic Sea. These events were accompanied by massive destruction of wooden ships and coastal protection structures. In this study, the first population analysis of T. navalis is presented with the aim to detect the genetic population structure in the waters of Central Europe. The mtDNA COI (cytochrome c oxidase subunit I locus was found as suitable molecular marker and hence a 675 bp gene fragment was studied. A total of 352 T. navalis specimens from 13 different sampling sites distributed across Central Europe were examined. Subsequently, various population genetic indices including FST values and an AMOVA analysis were applied for the description of the population structure. To visualize the distribution of haplotypes at the different sampling sites two median-joining networks were calculated. In addition, the past demographic structure of the T. navalis population was analyzed, among others by calculating Tajima's D, Fu's F and the mismatch distribution. Finally, all computations of the population genetic indices could not reveal differentiated populations or any kind of distinct population structure in T. navalis. The network analyses revealed “star-like” patterns without differentiated substructures or demes. Therefore, it can be assumed that a sudden expansion of this species took place without any indications of neither a bottleneck nor a founder effect for the study area. The results of this study support the concept of a regional panmictic population in the waters of Central Europe with unhindered migration of individuals (e.g., via pelagic larvae between the various sampling sites as reflected by a high gene flow.

  20. Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil

    International Nuclear Information System (INIS)

    Seo, Daniele

    2012-01-01

    The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of São Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in São Paulo coast are located in the geographical areas 23º 37'S - 45° 24' W (Caraguatatuba) and 23º 57'S - 46º 20' W (Santos). The collection of organisms was performed in all seasons of the year, beginning in spring 2008 and ending in winter 2009. The samples

  1. Perfil de lípidos y ácidos grasos de Perna viridis, mejillón verde (Mollusca: Bivalvia en el oriente venezolano y la costa oeste de Trinidad

    Directory of Open Access Journals (Sweden)

    Tamar Koftayan

    2011-03-01

    Full Text Available Los lípidos totales fueron extraídos, identificados y cuantificados por gravimetría, mediante TLC/FID (sistema Iatroscan. Los ácidos grasos de los lípidos totales, fosfolípidos y triacilgliceroles fueron identificados y cuantificados por cromatografía de gases. Las mayores concentraciones de lípidos totales se presentaron en las muestras de Los Cedros, La Brea y Chaguaramas con valores de 7.92, 7.74 y 7.53%; respectivamente y los valores mínimos en las de La Restinga (6.08%. En la composición lípidica, las muestras de Chacopata presentaron la menor concentración de fosfolípidos (48.86% y los máximos valores de colesterol (38.87% y triacilgliceroles (12.26%, y las muestras de La Esmeralda y Río Caribe exhibieron concentraciones máximas de fosfolípidos (88.71-84.93%, respectivamente y mínimas de colesterol (6.50-4.42%. En los lípidos totales, los ácidos grasos saturados se encontraron entre 15.04 y 65.55%, con máximos en muestras de La Esmeralda y mínimos en Chacopata y los poliinsaturados estuvieron entre 7.80 y 37.18%, con máximos valores en la Brea y mínimos en la Esmeralda. En los fosfolípidos, la concentración de ácidos grasos saturados estuvo entre 38.81 y 48.68% para las muestras de Chaguaramas y Chacopata, respectivamente; los ácidos grasos poliinsaturados se encontraron entre no detectado y 34.51%, con altas concentraciones en muestras de Los Cedros (27.97% y Chaguaramas (34.51%. En los triacilgliceroles, la composición de ácidos grasos saturados variaron entre 14.27 y 53.80%, con baja concentración en Chacopata y alta concentración en La Restinga; los ácidos grasos poliinsaturados estuvieron entre 4.66 y 35.55%, con valores menores en las muestras de Chacopata (4.66% y mayores en Chaguaramas. El consumo frecuente de Perna viridis es recomendable, debido a su alto contenido de fosfolípidos y ácidos grasos insaturados.Lipid and fatty acid profile of Perna viridis, Green Mussel (Mollusca: Bivalvia in

  2. Ocorrência do bivalve exótico Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, no Brasil Occurrence of exotic bivalve Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, in Brazil

    Directory of Open Access Journals (Sweden)

    José R. B. de Souza

    2005-12-01

    Full Text Available O molusco Mytilopsis leucophaeta (Conrad, 1831, natural da América do Norte, foi localizado no litoral de Pernambuco, Brasil, em 2004, trazido provavelmente por água de lastro de navios. Na região, sua distribuição atualmente abrange zonas estuarinas adjacentes ao Porto do Recife. Os organismos foram encontrados restritos à região entre-marés, formando agregados densos com até 176.800 ind./m².The mussel Mytilopsis leucophaeta (Conrad, 1831 is native to North America. It was found at Pernambuco Coast, northeastern Brazil, in 2004, probably brought by ships' ballast water. The distribution of this species has been now spread to estuarial area near Recife Harbour. They showed a clumped distribution with a maximum of 176,800 ind./m² only in the intertidal zone.

  3. Systematic reviews on the Mesodesmatidae (Mollusca, Bivalvia) I. The Genus Monterosatus Beu, 1971

    NARCIS (Netherlands)

    Rooij-Schuiling, de L.A.

    1977-01-01

    In trying to identify a small Mesodesma from West Irian, New Guinea, much material in the collections of several museums was studied. As a guide for the identification I at first used the revision of the Mesodesmatidae by Lamy (1914), which is based exclusively on the collections of the Parisian

  4. A biomechanical model of rock drilling in the piddock Barnea candida (Bivalvia; Mollusca)

    NARCIS (Netherlands)

    Nederlof, R.; Muller, M.

    2012-01-01

    The bivalve Barnea candida (Pholadacea) makes its burrow in clay, soft rock and peat. Barnea has developed a number of adaptations to accommodate this lifestyle. Four muscles enable burrowing. These are situated around a dorsal pivot in such a way that the piddock is able to rotate the shells around

  5. Using DNA barcoding to differentiate invasive Dreissena species (Mollusca, Bivalvia

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    Jonathan Marescaux

    2013-12-01

    Full Text Available The zebra mussel (Dreissena polymorpha and the quagga mussel (Dreissena rostriformis bugensis are considered as the most competitive invaders in freshwaters of Europe and North America. Although shell characteristics exist to differentiate both species, phenotypic plasticity in the genus Dreissena does not always allow a clear identification. Therefore, the need to find an accurate identification method is essential. DNA barcoding has been proven to be an adequate procedure to discriminate species. The cytochrome c oxidase subunit 1 mitochondrial gene (COI is considered as the standard barcode for animals. We tested the use of this gene as an efficient DNA barcode and found that it allow rapid and accurate identification of adult Dreissena individuals.

  6. Using DNA barcoding to differentiate invasive Dreissena species (Mollusca, Bivalvia).

    Science.gov (United States)

    Marescaux, Jonathan; Van Doninck, Karine

    2013-12-30

    The zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena rostriformis bugensis) are considered as the most competitive invaders in freshwaters of Europe and North America. Although shell characteristics exist to differentiate both species, phenotypic plasticity in the genus Dreissena does not always allow a clear identification. Therefore, the need to find an accurate identification method is essential. DNA barcoding has been proven to be an adequate procedure to discriminate species. The cytochrome c oxidase subunit I mitochondrial gene (COI) is considered as the standard barcode for animals. We tested the use of this gene as an efficient DNA barcode and found that it allow rapid and accurate identification of adult Dreissena individuals.

  7. The Recent Pectinoidea of the New Zealand region (Mollusca: Bivalvia: Propeamussiidae, Pectinidae and Spondylidae)

    NARCIS (Netherlands)

    Dijkstra, H.H.; Marshall, B.A.

    2008-01-01

    The Recent Pectinoidea of the New Zealand region are reviewed. Eight new species are described from the New Zealand Exclusive Economic Zone: Parvamussium cancellorum, Cyclochlamys austrina, Cc. delli, Cc. irregularis, Cc. munida, Cc. pileolus, Cyclopecten fluctuosus, and Catillopecten tasmani. Nine

  8. The sensorial structures of Spondylus americanus Hermann,1781 (Mollusca: Bivalvia, Spondylidae

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    Marina Gomes Viana

    2007-09-01

    Full Text Available Adult animals of Spondylus americanus were analyzed and specialized sensorial structures, the sensorial papillae and the eyes, were characterized. The sensorial papillae were projections on the edge of the mantle in form of light brown fingers which had function of percepting stimulus coming from the medium. They were constituted by loose conjunctive tissues with longitudinal muscular fibers and externally covered by ciliated cubic epithelium, which presented high amount of melanocytes that gave the coloration of the papillae. The eyes were more complex, being on small stalks histologically similar to the papillae. They exhibited a circular formate and had a metallic blue color. Theses structures were constituted by a corneo epithelium, cornea, lens, retina, basal stalk, periocular band and optical nerve. The eyes were distributed asymmetrically to both valves related with the sedentarism of the species. Right valve presented a smaller number of eyes when compared to left one.Foram examinados exemplares adultos de Spondylus. americanus Hermann, 1781 e estruturas especializadas na percepção de estímulos foram caracterizadas: as papilas sensoriais e os ocelos. As papilas sensoriais são projeções do bordo manto em forma de dedos de cor castanha e com a função de perceber estímulos vindo do meio, são constituídas por tecido conjuntivo frouxo contendo fibras musculares longitudinais e revestidas externamente por epitélio cúbico ciliado, o qual apresenta grande quantidade de melanócitos, que dão a coloração das papilas. Os ocelos são mais complexos, estando sobre pequenos pedúnculos histologicamente semelhante às papilas, têm formato circular e possui cor azul metálica. Constituí-se por um epitélio córneo, córnea, lente, retina, pedúnculo basal, banda periocular e nervo óptico. Os ocelos distribuem-se assimetricamente por ambas as valvas, o que está relacionado com o sedentarismo da espécie. A valva direita apresenta menor número de ocelos quando comparada a esquerda.

  9. Caloric variability of Corbicula fluminea (Mollusca, Bivalvia in Rosana Reservoir, Brazil

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    Yara Moretto Bagatini

    2007-01-01

    Full Text Available The purpose of the present study was to investigate temporal and longitudinal variation of caloric density of Corbicula fluminea in Rosana Reservoir. Significant differences concerning the caloric density of C. fluminea were observed throughout the year at the three reservoir sites. The caloric density variation during the year was probably related to reproductive activity, which demanded higher allocation of energy in certain period. The food source used by this species might be an important factor in the caloric value temporal and spatial variation of C. fluminea in Rosana Reservoir.O objetivo deste estudo foi investigar a variação temporal e longitudinal da densidade calórica de C. fluminea no reservatório de Rosana. Diferenças significativas na densidade calórica de C. fluminea foram observadas ao longo do ano e nas três estações do reservatório. A variação na densidade calórica de C. fluminea, durante o ano, provavelmente foi relacionada à atividade reprodutiva, que exige uma maior alocação de energia em determinado período. O recurso alimentar utilizado por esta espécie pode ser um importante fator na variação temporal e espacial do valor calórico de C. fluminea no reservatório de Rosana.

  10. The effect of temperature and body size on filtration rates of Limnoperna fortunei (Bivalvia, Mytilidae under laboratory conditions

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    Débora Pestana

    2009-02-01

    Full Text Available The golden mussel (Limnoperna fortunei, Mollusca: Bivalvia is an invasive species that has been causing considerable environmental and economic problems in South America. In the present study, filtration rates of L. fortunei were determined in the laboratory under different temperatures (10, 15, 20, 25, 28, and 30 ºC and two types of food (Algamac-2000® and the chlorophycean alga Scenedesmus sp.. There was a statistically significant relationship between time and filtration rates in the experiment using Scenedesmus sp., regardless of temperature. However, this pattern was absent in the experiment using Algamac, suggesting that the relationship between filtration rates and temperature might depend on the size of the filtered particles. In addition, there was no correlation between filtration rates and either shell size or condition index (the relationship between the weight and the length of a mussel. The filtration rate measured in the present study (724.94 ml/h was one of the highest rates recorded among invasive bivalves to date. Given that the colonies of the golden mussel could reach hundreds of thousands of individuals per square meter, such filtration levels could severely impact the freshwater environments in its introduced range.

  11. De weekdieren van de Nederlandse brakwatergebieden (Mollusca)

    NARCIS (Netherlands)

    Kuijper, W.J.

    2000-01-01

    The molluscs of the brackish waters in the Netherlands (Mollusca) The Netherlands is a river delta rich in brackish waters. The organisms in these waters need to be adapted to extreme conditions, especially large fluctuations in chlorinity. However, several species occur optimally in this habitat.

  12. Notes on Loricata (Mollusca) 11-14

    NARCIS (Netherlands)

    Kaas, P.

    1985-01-01

    Four new species of chitons (Mollusca, Polyplacophora) are described, viz Leptochiton (L.) dispersus and L. (L.) permodestus from Transkei, L. (L.) meiringae from the eastern Cape Province, S Africa (note 11) and Ischnochiton (Stenosemus) vanbellei from the Mediterranean Sea (note 14). New records

  13. [Species composition and distribution of medical mollusca in Shanghai City].

    Science.gov (United States)

    Guo, Yun-hai; Lv, Shan; Gu, Wen-biao; Liu, He-xiang; Wu, Ying; Zhang, Yi

    2015-02-01

    To investigate the species diversity and distribution of medical mollusca in Shanghai City. From August 2012 to October 2013, all kinds of habitats in 8 districts and counties in Shanghai City, namely Jiading, Qingpu, Baoshan, Minhang, Songjiang, Jinshan, Chongming, Pudong, were selected for the field survey according to the distribution characteristics of the river system, and all the specimens of medical mollusca in the investigation sites were collected and classified by morphological identification. Meanwhile, the species composition, habitats as well as the fauna of the medical mollusca collected were analyzed. A total of 5,211 specimens were collected, which belonged to 2 classes, 14 families, 18 genera and 25 species, including Oncomelania hupensis hupensis, Pomacea canaliculata, Parafossarulus striatulus, Alocinma longicornis, Physa acuta, Galba pervia, Hippeutis cantori, etc. The species numbers of medical mollusca in Chongming, Jinshan, Pudong new area and Qingpu districts (counties) were 22, 22, 21 and 20, respectively, which were more than those of other areas. The habitat analysis suggested that the species numbers in the river and wetland were the most, both of which were 14 species. The main faunas of the medical mollusca in Shanghai were the cosmopolitan and oriental species. The freshwater gastropod species are paucity in Shanghai City, but almost of them can be served as the intermediate hosts of certain parasites to transmit snail-related parasitic diseases, so the surveillance of medical mollusca should be strengthened.

  14. Metabolism of 60Co in mollusca

    International Nuclear Information System (INIS)

    Nakahara, Motokazu

    1983-01-01

    After mollusca were bred in 60 Co-labeled sea water or were given 60 Co-labeled feed for certain hours, their tissues including the liver were removed as experimental samples. 60 Co metabolism was observed by the Sephadex gel filtration profile. A gel chromatogram of the liver in gastropoda showed a marked peak of 60 Co on the high-molecular side. Although the peak was observed on both high- and low-molecular sides in pelecypoda, it was more marked on the high-molecular side than on the low-molecular side. In cephalopoda, the peak pattern was similar to that in the other mollusca, but the proportion of low-molecular components was comparatively large. The gel filtration profile of 60 Co in various tissues of cephalopoda revealed the incorporation of 60 Co into the high-molecular components in blood, three peaks in the kidneys, and the incorporation of 60 Co into the low-molecular components in the branchial heart. The metabolism of 60 Co was dependent upon the chemical form of Co in gastropoda, and organic 60 Co was specifically observed in the high-molecular components. (Namekawa, K.)

  15. Accumulation of cesium-137 by useful mollusca

    International Nuclear Information System (INIS)

    Suzuki, Yuzuru; Nakahara, Motokazu; Nakamura, Ryoichi

    1978-01-01

    There are few data available on the radioactive contamination of marine mollusca, especially cephalopoda. Therefore, in this paper, data obtained on the radioactive contamination of cephalopoda were compared with those on pelecypoda and gastropoda. The uptake and elimination experiments were carried out by means of radioisotope tracer methods, and the concentration factors of 137 Cs due to radioactive fallout were estimated. The contamination of cephalopoda was also compared with those of other marine organisms in terms of concentration factor. The activity ratios in the organs or tissues of octopus were in the range of 3.5 and 12.8 on the 14th day after the beginning of exposure and those of squid were in the range of 8.8 and 10.9 on the 6th day after the commencement of the experiment. The biological half time was 90 days for octopus from the observation over 75 days, while it was 31 days for clam from the results of 75 days' experiment. The concentration factors of 137 Cs due to radioactive fallout were in the range of 3 and 23 for cephalopoda, 7 and 28 for pelecypoda and 24 and 30 for gastropoda, respectively. It was concluded that no difference in the concentration factors was clearly observable among the classes of mollusca, but the values were substantially similar to those of crustaceans and slightly lower than those of marine fish. (auth.)

  16. The effects of mercury exposure on the surface morphology of gill filaments in Perna perna (Mollusca: Bivalvia)

    CSIR Research Space (South Africa)

    Gregory, MA

    1999-01-01

    Full Text Available each animal were analysed for mercury using an atomic absorption spectrometer. Mercury concentration increased from 0.13 (pre-immersion) to 87 mu g/g after day 24. Surface morphology remained normal for all animals in tank 2 and for those exposed to Hg...

  17. Seasonal variation in the abundance and distribution of Anomalocardia flexuosa (Mollusca, Bivalvia, Veneridae in an estuarine intertidal plain

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    Jacqueline S. Silva-Cavalcanti

    2018-02-01

    Full Text Available Spatial and temporal density and biomass of the infaunal mollusk Anomalocardia flexuosa (Linnaeus, 1767 evaluated a tidal plain at Goiana estuary (Northeast Brazil. Three hundred and sixty core samples were taken during an annual cycle from three intertidal habitats (A, B and C. Shell ranged from 2.20 to 28.48 mm (15.08 ± 4.08 mm. Recruitment occurred more intensely from January to March. Total (0–1,129 g m−2 differed seasons (rainy and dry, with highest values in the early rainy season (221.0 ± 231.44 g m−2; and lowest values in the late dry season (57.34 ± 97 g m−2. The lowest occurred during the late rainy (319 ± 259 ind m−2 and early dry (496 ± 607 ind m−2 seasons. Extreme environmental situations (e.g., river flow, salinity and water temperature at the end of each season also affected density ranges (late dry: 0–5,798 ind m−2; late rainy: 0–1,170 ind m−2. A. flexuosa in the Goiana estuary presented a dominance of juvenile individuals (shell length < 20 mm, with high biomass main the recruitment period. Average shell length, density and biomass values suggest overfishing of the stock unit. A. flexuosa is an important food and income resource along its whole distribution range. The species was previously also known as Anomalocardia brasiliana (Gmelin, 1791.

  18. Effect of zinc and benzene on respiration and excretion of mussel larvae (Perna perna (Linnaeus, 1758 (Mollusca; Bivalvia

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    RADLVC. Jorge

    Full Text Available The presence of pollutants in the ocean may affect different physiological parameters of animals. Oxygen consumption and ammonia excretion were evaluated in D-shaped larvae of mussels (Perna perna exposed to zinc sulphate (ZnSO4 and benzene (C6H6. When compared to the control group, both pollutants presented a significant reduction in oxygen consumption. A reduction in the ammonia excretion was also observed, both for ZnSO4 and C6H6 and also in the oxygen consumption. The results indicate that anaerobic metabolism may occur at the beginning of P. perna mussels development, as observed in veliger larvae. The O:N ratio under experimental conditions showed low values indicating that catabolism in veliger larvae was predominantly proteic.

  19. Isolation and Characterization of the First Microsatellite Markers for the Endangered Relict Mussel Hypanis colorata (Mollusca: Bivalvia: Cardiidae

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    Luis Ovidiu Popa

    2011-01-01

    Full Text Available Hypanis colorata (Eichwald, 1829 (Cardiidae: Lymnocardiinae is a bivalve relict species with a Ponto-Caspian distribution and is under strict protection in Romania, according to national regulations. While the species is depressed in the western Black Sea lagoons from Romania and Ukraine, it is also a successful invader in the middle Dniepr and Volga regions. Establishing a conservation strategy for this species or studying its invasion process requires knowledge about the genetic structure of the species populations. We have isolated and characterized nine polymorphic microsatellite markers in H. colorata. The number of alleles per locus ranged from 4 to 28 and the observed heterozygosity ranged from 0.613 to 1.000. The microsatellites developed in the present study are highly polymorphic and they should be useful for the assessment of genetic variation within this species.

  20. Recrutamento larval e crescimento de teredinidae (mollusca-bivalvia em região entremarés de manguezais

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    Sônia Godoy Bueno Carvalho Lopes

    1997-01-01

    Full Text Available O recrutamento larval e o crescimento de Teredinidae na região entremarés do manguezal da Praia Dura, Ubatuba, SP, foi acompanhado durante doze meses (08/84 a 08/85 utilizando coletores construídos com madeira de mangue. O tempo decorrido para se detectar a presença dos primeiros Teredinidae foi de aproximadamente sete meses após o início do experimento e o número de indivíduos por coletor foi muito reduzido no período de amostragem. Esses resultados contrastam com os obtidos por outros autores que instalaram coletores em ambiente marinho, mas são semelhantes aos obtidos por autores que instalaram coletores em regiões estuarinas do litoral brasileiro. Essas diferenças nos resultados talvez possam ser explicadas pelo fato da salinidade ser mais baixa e mais variável nos estuários que no ambiente marinho. A análise dos dados sobre o recrutamento larval, permite concluir que a espécie mais abundante foi Nausitora fustieula (Jeffreys, 1860, com principal época de instalação em março e taxa inicial de crescimento de 1,86 mm/day. As outras espécies de Teredinidae, Bankiaflmbriatula Moll & Roch, 1931, Bankia roehi Moll, 1931 e Neoteredo reynei (Bartsch, 1920, apresentaram pequeno número de indivíduos e em função disso, não foi possível determinar suas épocas de instalação e respectivas taxas de crescimento.The larval settlement and growth of Teredinidae in the intertidal region of the Praia Dura mangrove, Ubatuba, SP, were undertaken during one year (08/84 to 08/85 using colectors made from mangrove wood. The presence of the first Teredinidae was detected approximately seven month after the inicial experiment and the number of specimens per coletor was small during the sampling period. These results contrast with those obtained by other authors working in a marine environment, but are similar to those obtained in experiments developed in Brazilian estuaries. The differences between data obtained in marine and estuarine environments, might be explained by the lower and more variable salinity gradient in estuaries. Larval settlement data revealed that the most abundant species was Nausitora fustieula (Jeffreys,1860, which settles on wood prefrerably in March, and has an initial growth rate of 1.86 mm/day. The other Teredinidae species Banida fimbriatula Moll & Roch, 1931, Bankia rochi Moll, 1931 and Neoteredo reynei (Bartsch, 1920, occurred in a very small number of specimens and therefore, their time of settlement and growth rates could not be determined.

  1. Comparative studies on the histology and ultrastructure of the siphons of two species of Tellinidae (Mollusca: Bivalvia from Brazil

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    João E.V.V. Vitonis

    2012-06-01

    Full Text Available Despite the great importance of the siphons for infaunal bivalves, only a few studies have examined their tissues using histology techniques or scanning electron microscopy. In the present study, the siphons of Tellina lineata Turton, 1819 and Macoma biota Arruda & Domaneschi, 2005 were investigated. The siphon walls are composed by a series of muscle sheets of longitudinal ("L", circular ("C" and radial ("R" fibers, with a clear pattern common to both species: there is a main median longitudinal layer (Lm, and two peripheral circular layers, one inner (Ci and one outer (Co, near the epithelia. A median circular layer (Cm separates an internal (Lmi from an outer (Lmo median longitudinal layer. Further, the Co is split by a thin outer longitudinal layer (Lo, forming Coi and Coo layers, the former being obliquely oriented. Thin radial fibers (R delimit clear packages of Lmi and Lmo fibers. In each siphon, there are six longitudinal nerve cords, running within the Lmi layer, adjacent to the Cm. The inhalant and exhalant siphons of M. biota are very similar in structure, but the Lmo of the exhalant siphon is almost twice as thick as its Lmi, while in the inhalant siphon these layers have similar thicknesses; the Coi is very thick, especially in the exhalant siphon. The inhalant siphon of T. lineata is very similar to that of M. biota, differing only with respect to the thickness of the Coi, which in the former species is not as well developed as in the latter. The Lmo of the exhalant siphon of T. lineata is by far the most developed layer, with the Lmi represented only by uniseriate small cells; in the vicinities of the nerve cords, the Cm is split in two layers. The epithelia of both siphons of M. biota and T. lineata bear ciliated receptors, which were difficult to observe as they were frequently covered with mucus. It was possible to observe that cilia are present in both species, differing in length and in the number per receptor between the inhalant and exhalant siphons, and between the species. Detailed comparisons among the siphons of M. biota and T. lineata and other bivalve species are very difficult, because of at least two reasons. First, each investigator has used different methods to prepare and observe the siphons through histological sections; and second, different nomenclatural schemes are used to describe the musculature of the siphons, causing confusion when the same layers are compared among different species. In order to unify the nomenclature of tissue layers of the bivalve siphons, we now propose a scheme to name these layers based on topological homology.

  2. In situ distribution and characterization of the organic content of the oyster shell Crassostrea gigas (Mollusca, Bivalvia).

    Science.gov (United States)

    Dauphin, Yannicke; Ball, Alexander D; Castillo-Michel, Hiram; Chevallard, Corinne; Cuif, Jean-Pierre; Farre, Bastien; Pouvreau, Stéphane; Salomé, Murielle

    2013-01-01

    Cultivation of commercial oysters is now facing the possible influence of global change in sea water composition, commonly referred to as "ocean acidification". In order to test the potential consequence of the predicted environmental changes, a cultivation experiment was carried out. The left and right valves of the oyster shell Crassostrea gigas differ in their structure; moreover, lenses of non compact layers are irregular. The shell layers of juvenile C. gigas are studied using a variety of highly spatially resolved techniques to establish their composition and structure. Our results confirm the presence of three different calcitic structural types. The role of the lenses of chalky layers is not yet deciplered. Despite a common mineralogy, the elemental composition of the layers differs. The sulphur aminoacids and sulphated polysaccharide contents of the intracrystalline and intercrystalline matrices differ, as well as those of the structural types. The possible different sensitivity of these structures to environmental changes is still unknown. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Symbiotic relationship between the carapid fish Onuxodon fowleri (Ophidiiformes: Carapidae and the pearl oyster Pinctada margaritifera (Mollusca: Bivalvia: Pteriidae

    Directory of Open Access Journals (Sweden)

    Orphal Colleye

    2018-03-01

    Full Text Available At Makemo Atoll (French Polynesia, the carapid fish Onuxodon fowleri lives in symbiosis with the black-lip pearl oyster Pinctada margaritifera. Although the symbiont seems to live inside its host bivalve by using it as a shelter, additional data are still needed to better understand the exact nature of this association. For this purpose, we implemented an approach using stable isotope ratios of carbon (13C/12C and nitrogen (15N/14N. The δ13C and δ15N values were measured in tissues of the pearl oyster (gonads, gills, mantle and muscles, white muscle tissue from the fish and other food sources. This stable isotope approach was also complemented by the analysis of stomach contents in the carapid fish. Overall, the isotopic compositions measured in the present study support a commensal relationship between O. fowleri and P. margaritifera. In addition, our isotopic data bring new information about another guest living inside P. margaritifera, namely the palaemonid shrimp Conchodytes meleagrinae. Based on the δ13C and δ15N values, it appears that the shrimp might feed on the bivalve gonads.

  4. Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia : Mollusca)

    NARCIS (Netherlands)

    Cavanaugh, Colleen M.; Abbott, Marilyn S.; Veenhuis, Marten

    1988-01-01

    The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large

  5. Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia: Mollusca).

    Science.gov (United States)

    Cavanaugh, C M; Abbott, M S; Veenhuis, M

    1988-10-01

    The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP(2)Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large subunit of RbuP(2)Case from tobacco (Nicotiana tabacum) cross-reacted on immunoblots with a protein of similar molecular mass occurring in extracts of the symbiont-containing gill tissue of S. velum. No cross-reactivity was detected in symbiont-free tissue extracts. The antiserum also cross-reacted in immunoblots with proteins of Thiobacillus neapolitanus, a free-living sulfuroxidizing chemoautotroph whose RbuP(2)Case has been well characterized. In protein A-gold immunoelectron microscopy studies, this antiserum consistently labeled the symbionts but not surrounding host gill tissue, indicating that the symbionts are responsible for the RbuP(2)Case activity.

  6. Microsatellite loci for dreissenid mussels (Mollusca: Bivalvia: Dreissenidae) and relatives: markers for assessing exotic and native populations.

    Science.gov (United States)

    Feldheim, Kevin A; Brown, Joshua E; Murphy, Douglas J; Stepien, Carol A

    2011-07-01

    We developed and tested 14 new polymorphic microsatellite loci for dreissenid mussels, including the two species that have invaded many freshwater habitats in Eurasia and North America, where they cause serious industrial fouling damage and ecological alterations. These new loci will aid our understanding of their genetic patterns in invasive populations as well as throughout their native Ponto-Caspian distributions. Eight new loci for the zebra mussel Dreissena polymorpha polymorpha and six for the quagga mussel D. rostriformis bugensis were compared with new results from six previously published loci to generate a robust molecular toolkit for dreissenid mussels and their relatives. Taxa tested include D. p. polymorpha, D. r. bugensis, D. r. grimmi, D. presbensis, the 'living fossil'Congeria kusceri, and the dark false mussel Mytilopsis leucophaeata (the latter also is invasive). Overall, most of the 24 zebra mussel (N = 583) and 13 quagga mussel (N = 269) population samples conformed to Hardy-Weinberg equilibrium expectations for the new loci following sequential Bonferroni correction. The 11 loci (eight new, three previously published) evaluated for D. p. polymorpha averaged 35.1 alleles and 0.72 mean observed heterozygosity per locus, and 25.3 and 0.75 for the nine loci (six new, three previously published) developed for D. r. bugensis. All but three of these loci successfully amplified the other species of Dreissena, and all but one also amplified Congeria and Mytilopsis. All species and populations tested were significantly divergent using the microsatellite data, with neighbour-joining trees reflecting their evolutionary relationships; our results reveal broad utility for resolving their biogeographic, evolutionary, population and ecological patterns. © 2011 Blackwell Publishing Ltd.

  7. Biomonitoring study of an estuarine coastal ecosystem, the Sacca di Goro lagoon, using Ruditapes philippinarum (Mollusca: Bivalvia)

    International Nuclear Information System (INIS)

    Sacchi, Angela; Mouneyrac, Catherine; Bolognesi, Claudia; Sciutto, Andrea; Roggieri, Paola; Fusi, Marco; Beone, Gian Maria; Capri, Ettore

    2013-01-01

    Coastal lagoons are constantly subjected to releases of chemical pollutants, and so organisms may be exposed to such toxicants. This study investigated through a multivariate approach the physiological status of bivalve Ruditapes philippinarum, farmed in Sacca di Goro lagoon. Biomarkers at different levels of biological organization (catalase, superoxide dismutase, genotoxicity, reburrowing behavior) were evaluated at three sites exposed to different environmental conditions. A seasonal trend was observed, and micronucleus frequency was significantly lowest at the relatively pristine reference site. Enzymatic activity toward oxyradicals be quite efficient since variations in responsiveness were not consistent. However, behavioral impairment was observed in reburrowing rates. Sediment concentrations showed low PAH levels and high natural levels of trace metals Cr and Ni. DistLM statistical analysis revealed a non-significant relationship between selected biomarkers and xenobiotics. Therefore other potentially toxic compounds in admixture at low doses may be involved in driving differing spatial distribution of physiological impairment. -- Highlights: ► Health status assessment of bivalve Ruditapes philippinarum, from lagoon of Sacca di Goro. ► Multiparametric approach (chemical analysis, biochemical and behavioral biomarkers). ► Impairments of burrowing kinetics in the contaminated site. ► Micronucleus genotoxicity test to detect effects of contaminants complex mixture. ► Multiple stress of chemicals in estuarine costal ecosystem. -- The bivalve Ruditapes philippinarum as a bioindicator in monitoring pollution of estuaries

  8. Anatomy and systematics of Anodontites Elongatus (Swainson from Amazon and Parana Basins, Brazil (Mollusca, Bivalvia, Unionoida, Mycetopodidae

    Directory of Open Access Journals (Sweden)

    Luiz Ricardo L Simone

    1997-12-01

    Full Text Available The anatomy of Anodontiies elongatus (Swainson, 1823, a rare species restricted to the Amazon and Parana Basins, is described by first time, showing a group of conchological and anatomical characters exclusive of this species that may be analyzed to identify it. Diagnosis of A. elongatus: shell long antero-posteriorly, umbones prominent, periostracum opaque and smooth, two posterior radial striae; middle fold of mantle edge veiy tall; gill long antero-posteriorly and short dorso-ventrally, extending about a half of it total length beyond visceral mass; palps proportionally small, several furrows in its outer surface; stomach without esophageal transversal ridjp, dorsal hood and gastric shield poorly developed, major typhlosole entering in ddd , posterior pouch of sa³ very-long; style sac reduced, without crystalline style; distal region of intestine and rectum with a well developed typhlosole, "T" in section, other intestinal regions without folds; gonad gonochoristic.

  9. Effect of heavy metals (Cu, Cd and Pb) on aspartate and alanine aminotransferase in Ruditapes philippinarum (Mollusca: Bivalvia)

    International Nuclear Information System (INIS)

    Blasco, J.; Puppo, J.

    1999-01-01

    The accumulation of cadmium, copper and lead and their effects on aspartate and alanine aminotransferases in digestive gland, gills, foot and soft body in the clam Ruditapes philippinarum were examined. The animals were exposed to different concentrations: Cd (200-600 μg·l -1 ), Pb (350-700 μg·l -1 ) and Cu (10-20 μg·l -1 ) for 7 days. The highest concentrations were found in digestive gland for cadmium and copper, and in gills for lead, and the lowest values were observed in the foot. Aspartate aminotransferase activity (AST), in general, was not inhibited by cadmium, lead or copper during the exposure. Only in clams exposed to cadmium (600 μg·l -1 , 7 days) and copper (20 μg·l -1 , 5 days) were observed significant differences (P -1 . A significant correlation (P<0.05) was observed between ALT and metal accumulation for cadmium, copper and lead in gills. In the case of soft body, only cadmium and lead showed a significant correlation. In summary, R. philippinarum can be considered a bioindicator species for cadmium and lead accumulation and ALT could be useful as biomarker of sublethal stress for these metals in soft tissues and gills. Only gills can be considered an adequate target tissue for copper. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Cytogenetic characterisation of the razor shells Ensis directus (Conrad, 1843) and E. minor (Chenu, 1843) (Mollusca: Bivalvia)

    Science.gov (United States)

    González-Tizón, Ana M.; Rojo, Verónica; Vierna, Joaquín; Jensen, K. Thomas; Egea, Emilie; Martínez-Lage, Andrés

    2013-03-01

    The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric-submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric-submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua.

  11. Molecular discrimination of Perna (Mollusca: Bivalvia) species using the polymerase chain reaction and species-specific mitochondrial primers

    DEFF Research Database (Denmark)

    Blair, D.; Waycott, M.; Byrne, L.

    2006-01-01

    This work was prompted by the need to be able to identify the invasive mussel species, Perna viridis, in tropical Australian seas using techniques that do not rely solely on morphology. DNA-based molecular methods utilizing a polymerase chain reaction (PCR) approach were developed to distinguish...

  12. Aspects of the biology of Mya arenaria and Ensis spp. (Mollusca; Bivalvia) in the Irish Sea and adjacent areas

    OpenAIRE

    Cross, Maud E.

    2014-01-01

    This study was undertaken to investigate the general biology, including the reproductive cycle and health status, of two clam taxa in Irish waters, with particular reference to the Irish Sea area. Monthly samples of the soft shell clam, Mya arenaria, were collected from Bannow Bay, Co. Wexford, Ireland, for sixteen months, and of the razor clam, Ensis spp. from the Skerries region (Irish Sea) between June 2010 and September 2011. In 2010, M. arenaria in Bannow Bay matured over the summer mont...

  13. The Effects of Mercury Exposure on the Surface Morphology of Gill Filaments in Perna perna (Mollusca: Bivalvia)

    International Nuclear Information System (INIS)

    Gregory, M.A.; George, R.C.; Marshall, D.J.; Anandraj, A.; McClurg, T.P.

    1999-01-01

    This study investigated the possibility that changes in the surface morphology of mussel (Perna perna) gill filaments may be used to indicate the relative toxicity of pollutants in the marine environment. Healthy, adult P. perna were collected and immersed in 2 free-flow tanks. Mercury was added to seawater as it entered tank 1 to achieve a constant level of 50 μg/l -1 over 24 days. Uncontaminated seawater was circulated over the mussels in tank 2 (control) for the same period. A 25 mm 2 area of gill filament was removed from each of the 5 specimens before and after 24 days immersion in tank 2, and after immersion for 1, 2, 4, 8, 16 and 24 days in tank 1. These were examined using a scanning electron microscope. The remaining soft tissues from each animal were analysed for mercury using an atomic absorption spectrometer. Mercury concentration increased from 0.13 (pre-immersion) to 87 μg/g after day 24. Surface morphology remained normal for all animals in tank 2 and for those exposed to Hg for up to 8 days. However, from 16 to 24 days exposure there was a gradual increase in the diameters of microvilli, a depletion of abfrontal cilia, an increase in abnormal, perhaps necrotic cells and an unusual increase in the number of cilia on the lateral surfaces. These results confirm that P. perna is an efficient bio-accumulator and suggest that their gill pathomorphology may be a useful indicator of toxicity

  14. De nauwe korfslak Vertigo angustior in Nederland (Mollusca: Gastropoda)

    NARCIS (Netherlands)

    Bruyne, de R.

    2002-01-01

    The narrow whorlsnail Vertigo angustior in the Netherlands (Mollusca: Gastropoda) In June and July 2001, a special survey was held in several coastal areas in the province of Zuid- Holland, the Netherlands. The main objective was retrieving additional data on the occurrence of Vertigo angustior

  15. Overwinteringsgedrag van de nauwe korfslak Vertigo angustior (Mollusca)

    NARCIS (Netherlands)

    Boesveld, A.

    2005-01-01

    Overwintering habits of the land snail Vertigo angustior (Mollusca) During a mollusc survey in 2004 en 2005 in the province of Zuid-Holland special attention was paid to Vertigo angustior. The species was observed overwintering in large groups, up to hundreds of specimens together, between mosses

  16. Bibliographie der Flussperlmuschel Margaritifera Margaritifera (Linnaeus, 1758) [Mollusca: Pelecypoda

    NARCIS (Netherlands)

    Jungbluth, J.H.; Coomans, H.E.; Grohs, H.

    1985-01-01

    Bibliography of the freshwater Pearlmussel Margaritifera margaritifera (Linnaeus, 1758) [Mollusca: Pelecypoda] The freshwater pearlmussel, described by Linnaeus as Mya margaritifera is one of the most important molluscs existing. It belongs with only a few congeneric fossil and recent species to the

  17. A radioactivity study of mollusca distributed along the Syrian coast

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Ammar, I.; Mamish, S.; Haleem, M. A.

    2008-01-01

    In the present work, radioactivity has been studied in several Mollusca collected from four selected sites (Al Basset, Latakia, Banise and Tartous) along the Syrian coast. Concentration Factors (CF) of radionuclides (Lead-210, Polonium-210, Uranium Isotopes, Potassium-40 and Cesium-137) in mussels and shells of Mollusca have been calculated in order to determine the species that could be used as Bioindicators for these isotopes. Statistical analysis of the results using the box plot method showed that the mussels of Spondylus gaederopus spinosus and Chama pacifica can be used as biomonitor for the studied radionuclides in addition to shell of Strombus decorus persicus and Spondylus gaederopus spinosus. While the mussels of Brachidonta variabilis and Spondylus gaederopus spinosus have shown good selectivity for Cd and Pb and Pinctada radiate for Zn and Thais haemostoma for Cu. In addition, the migrant Mullusca from the Red Sea, Strombus decoruspersicus, can be used as biomonitor for lead, Zn and Cu, Cd, while the shell of Thais haemostoma for lead. However, the importance of the results of the present study that are considered as a baseline data for radionuclides in Mullusca distributed along the Syria coast and it is the only study in the eastern Mediterranean basin, that defined the Mollusca species which could be use as biomonitors for radionuclides. (Authors)

  18. A radioactivity study of mollusca distributed along the Syrian coast

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Ammar, I.; Mamish, S.; Haleem, M. A.

    2006-10-01

    In the present work, radioactivity has been studied in several Mollusca collected from four selected sites(Al Basset, Lattakia, Banise and Tartous) along the Syrian coast. Concentration Factors (CF) of radionuclides (Lead-210, Polonium-210, Uranium Isotopes, Potassium-40 and Cesium-137) in mussels and shells of Mollusca have been calculated in order to determine the species that could be used as Bioindicators for these isotopes. Statistical analysis of the results using the box plot method showed that the mussels of Spondylus spinosus and Chama pacifica can be used as biomonitor for the studied radionuclides in addition to shell of Strombus persicus and Spondylus spinosus. While the mussels of Brachidonta variabilis and Spondylus spinosus have shown good selectivity for Cd and Pb and Pinctada radiate for Zn and Thais haemostoma for Cu. In addition, the migrant Mullusca from the Red Sea, Strombus persicus, can be used as biomonitor for lead, Zn and Cu, Cd, while the shell of Thais haemostoma for lead. However, the importance of the results of the present study that are considered as a baseline data for radionuclides in Mullusca distributed along the Syria coast and it is the only study in the eastern Mediterranean basin, that defined the Mollusca species which could be use as biomonitors for radionuclides. (Authors)

  19. Types of Cenozoic Mollusca from Java in the Martin Collection of Naturalis

    NARCIS (Netherlands)

    Leloux, J.; Wesselingh, F.P.

    2009-01-01

    An updated type catalogue of the Martin Collection (fossil Mollusca, predominantly from the Cenozoic of Java, Indonesia) is presented. Type specimen data, updated locality data, and illustrations are given.

  20. DIVERSITAS DAN KERAPATAN MANGROVE, GASTROPODA DAN BIVALVIA DI ESTUARI PERANCAK, BALI

    OpenAIRE

    Susiana; Ali, Syamsu Alam; Rukminasari, Nita

    2011-01-01

    Penelitian ini bertujuan membandingkan diversitas dan kerapatan mangrove dengan kepadatan gastropoda dan bivalvia di mangrove alami dan rehabilitasi. Pengukuran ekosistem mangrove menggunakan transek kuadrat 10 m x 10 m. Kelimpahan dan kepadatan gastropoda dan bialvia menggunakan transek kuadrat berukuran 1 m x 1 m. Analisis nMDS, cluster untuk melihat hubungan karekteristik mangrove alami dan rehabilitasi dianalisis secara deskriptif dan analisis regresi untuk mendetermi...

  1. Distribución del género Diplodon (Mollusca: Bivalvia: Hyriidae en territorio Argentino mediante el uso de Colecciones Biológicas

    Directory of Open Access Journals (Sweden)

    Santiago Hernán Torres

    2013-10-01

    Full Text Available Los bivalvos nacaríferos dulciacuícolas (“náyades”, son especies infaunales, endémicas de la RegiónNeotropical, pertenecientes a las familias Hyriidae (Swaison, 1840 y Etheriidae (Swaison, 1840. La alteración del ambiente y la competencia con especies invasoras como Corbicula fluminea (Müller, 1774 y Limnoperna fortunei (Dunker, 1857, impactan sobre las poblaciones naturales. En esta comunicación, se presenta el inicio de un Proyecto de investigación sobre la distribución geográfica de las especies del género Diplodon en la Argentina. Estas especies son un componente importante de la infauna de los cuerpos lóticos y lénticos, viviendo en fondos limosos, limo-arenosos, excepcionalmente en sustratos duros, con un régimen nutricio filtrador, teniendo un papel importante como recicladores de materia orgánica. Conocer la distribución de los bivalvos pertenecientes al género Diplodon en el territorio Argentino permitirá el reconocimiento de potenciales áreas prioritarias para su conservación. Sobre la base de la bibliografía disponible y los ejemplares de las especies del genero Diplodon depositados en la Colección Malacológica del Museo de La Plata (FCNyM-UNLP, se confeccionó una matriz de datos que incluye la identificación del ejemplar, la colección en que se encuentra depositado, el número de catálogo, la localidad y la fecha de colecta. Cada localidad fue ubicada mediante el uso de cartas geográficas de Argentina y revisiones bibliográficas en imágenes satelitales de GoogleEarth, asignando las coordenadas para cada punto. Como resultado del trabajo se obtiene la distribución de estas especies nativas y se discute el grado de solapamiento con las dos especies de bivalvos invasores y el impacto de actividades humanas. 

  2. Reproductive activity and biochemical composition of the pullet carpet shell Venerupis senegalensis (Gmelin, 1791 (Mollusca: Bivalvia from Ria de Aveiro (northwestern coast of Portugal

    Directory of Open Access Journals (Sweden)

    Sandra Joaquim

    2011-06-01

    Full Text Available The present study characterizes the reproductive cycle of Venerupis senegalensis (=V. pullastra from Ria de Aveiro (Portugal as well as its nutrient storage and exploitation strategy. The reproductive cycle followed a seasonal cycle that correlated negatively with sea surface temperature, and comprised a ripe stage in winter followed by a spawning period that began in late winter and ended in the early summer. This extended spawning may be an advantageous strategy for the species because it ensures a continuous supply of settlers. Gametogenesis began in late summer/early autumn and intensified with the decrease in temperature during autumn. The condition index increased even during the spawning period, which indicates that there is rapid recovery and that reserves are accumulated during late summer and used later in the gametogenic process. Proteins did not contribute significantly to gametogenesis and the glycogen pattern is typical of conservative species, since gametogenesis depends largely on the amount of glycogen stored. The lipid storage and utilization cycle showed that gametogenesis took place in autumn/winter and that energy reserves were accumulated in summer.

  3. Evaluation of magnesium and manganese in Perna perna mussels (Linnaeus, 1758: mollusca, bivalvia) collected in the cost of the state of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiko; Cathartino, Marilia G.M.; Moreira, Edson G.; Sousa, Eduinetty C.P.M. de

    2011-01-01

    The objective of the present study was to evaluate magnesium and manganese concentrations in Perna perna mussels by applying instrumental neutron activation analysis (INAA). The mussels were collected seasonally from September 2008 to July 2009 at Cocanha Beach in the city of Caraguatatuba (clean region), and at two sites in Santos Bay (Ponta de Itaipu and Palmas Island). The mussel samples were cleaned, grinded, homogenized, lyophilized and then analyzed by INAA. The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 10 s, under a thermal neutron flux of 6.6 x 10 12 n cm -2 s -1 in the nuclear research reactor of IPEN-CNEN/SP. The measurements of the gamma radioactivity of the samples and standards were carried out using a hyperpure semiconductor Ge detector, coupled to Digital Spectral Analyzer. The elemental concentrations were calculated by the comparative method. For quality control of analytical results, certified reference materials NIST SRM 1566b oyster tissue and NRC DORM-2 Dogfish Muscle were analyzed and their results indicated good accuracy. The element concentrations in mussels on dry mass basis varied from 2734 ± 205 to 5138 ± 507 mg kg -1 for Mg and from 7.35±0.57 to 29.06±3.35 mg kg -1 for Mn. The results obtained in mussel analysis indicated that the samples collected in Itaipu in the winter season presented higher accumulation of Mg than the other sites. For Mn, the highest concentrations were obtained for the mussels collected in Palmas in summer time. (author)

  4. Threatened freshwater and terrestrial molluscs (Mollusca, Gastropoda et Bivalvia of Santa Catarina State, Southern Brazil: check list and evaluation of regional threats

    Directory of Open Access Journals (Sweden)

    2011-06-01

    Full Text Available A total of nineteen continental native mollusc species are confirmed for the Santa Catarina State (SC(organized in ten Genera and seven Families, one aquatic Prosobranchia/Caenogastropoda (Ampullariidae,six Pulmonata terrestrial gastropods (one Ellobiidae, three Megalobulimidae and two micro-snails –Charopidae and Streptaxidae and twelve freshwater mussels (eight Mycetopodidae and four Hyriidae. Thesespecies are designated by the International Union for Conservation of the Nature – IUCN as follows: seven as"Vulnerable", six "In Danger" and six “Without Category Established”. The general regional threats that thesespecies are subjected to are briefly analyzed.

  5. Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna Mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coast of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiki; Catharino, Marilia G.M.; Moreira, Edson G.; Sousa, Eduinetty C.P.M. de

    2013-01-01

    In this study the content of Br, Cl, K, Mg, Mn and V was evaluated in samples of Perna perna mussels collected in coastal regions of Sao Paulo (Ponta de Itaipu and Palmas Island, in Santos) subjected to anthropogenic contamination, to compare these values with those of mussels from reference site of Cocanha Beach (in Caraguatatuba). The mussels were collected seasonally from September 2008 to July 2009. They were cleaned, ground, homogenized, lyophilized and then analyzed by Instrumental Neutron Activation Analysis (INAA). The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 8 and 10 s, under a thermal neutron flux of 6.6 x 10 12 n cm -2 s -1 in the IEA-R1 nuclear research reactor. For quality control of analytical results, certified reference materials NIST 1566b Oyster Tissue and NIST 2876 Mussel Tissue were analyzed and their results indicated good accuracy. The ranges of concentrations (dry basis) of the elements obtained in mussels collected for the four seasons of the year were: 173.80 to 358.99 mg kg -1 for Br; 45658 ± 1811 to 109166 ± 824 mg kg -1 for Cl; 7043 ± 856 to 12506 ± 675 mg kg -1 for K; 2774 ± 211 to 5691 ± 717 mg kg -1 for Mg; 7.01 ± 0.30 to 29.74 ± 3.32 mg kg -1 for Mn and 0.77 ± 0.02 to 3.43 ± 0.28 mg kg -1 for V. The seasonal and spatial variations of these element concentrations were in this study. (author)

  6. Evaluation of magnesium and manganese in Perna perna mussels (Linnaeus, 1758: mollusca, bivalvia) collected in the cost of the state of Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiko; Cathartino, Marilia G.M.; Moreira, Edson G., E-mail: mbvascon@ipen.b, E-mail: mitiko@ipen.b, E-mail: emoreira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sousa, Eduinetty C.P.M. de, E-mail: edvinett@usp.b [Universidade de Sao Paulo (IO/USP), SP (Brazil). Inst. Oceanografico. Lab. de Ecotoxicologia Marinha e Microfitobentos

    2011-07-01

    The objective of the present study was to evaluate magnesium and manganese concentrations in Perna perna mussels by applying instrumental neutron activation analysis (INAA). The mussels were collected seasonally from September 2008 to July 2009 at Cocanha Beach in the city of Caraguatatuba (clean region), and at two sites in Santos Bay (Ponta de Itaipu and Palmas Island). The mussel samples were cleaned, grinded, homogenized, lyophilized and then analyzed by INAA. The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 10 s, under a thermal neutron flux of 6.6 x 10{sup 12} n cm{sup -2} s{sup -1} in the nuclear research reactor of IPEN-CNEN/SP. The measurements of the gamma radioactivity of the samples and standards were carried out using a hyperpure semiconductor Ge detector, coupled to Digital Spectral Analyzer. The elemental concentrations were calculated by the comparative method. For quality control of analytical results, certified reference materials NIST SRM 1566b oyster tissue and NRC DORM-2 Dogfish Muscle were analyzed and their results indicated good accuracy. The element concentrations in mussels on dry mass basis varied from 2734 {+-} 205 to 5138 {+-} 507 mg kg{sup -1} for Mg and from 7.35{+-}0.57 to 29.06{+-}3.35 mg kg{sup -1} for Mn. The results obtained in mussel analysis indicated that the samples collected in Itaipu in the winter season presented higher accumulation of Mg than the other sites. For Mn, the highest concentrations were obtained for the mussels collected in Palmas in summer time. (author)

  7. Characterization of nine microsatellite markers and development of multiplex PCRs for the Chinese huge musel Anodonta (Sinanodonta) woodiana Lea, 1834 (Mollusca, Bivalvia)

    Czech Academy of Sciences Publication Activity Database

    Popa, O. P.; Bartáková, Veronika; Bryja, Josef; Reichard, Martin; Popa, L. O.

    2015-01-01

    Roč. 60, June (2015), s. 234-237 ISSN 0305-1978 R&D Projects: GA ČR GA13-05872S Institutional support: RVO:68081766 Keywords : Invasive species * SSRs * Population genetics * Unionidae Subject RIV: EG - Zoology Impact factor: 0.988, year: 2015

  8. Molecular resolution of the family Dreissenidae (Mollusca: Bivalvia) with emphasis on Ponto-Caspian species, including first report of Mytilopsis leucophaeata in the Black Sea basin.

    Science.gov (United States)

    Therriault, Thomas W; Docker, Margaret F; Orlova, Marina I; Heath, Daniel D; MacIsaac, Hugh J

    2004-03-01

    Considerable uncertainty exists in determination of the phylogeny among extant members of the Dreissenidae, especially those inhabiting the Ponto-Caspian basin, as multiple systematic revisions based on morphological characteristics have failed to resolve relationships within this group of bivalves. In this study we use DNA sequence analyses of two mitochondrial gene fragments, 16S rRNA and cytochrome c oxidase subunit I (COI), to determine phylogenetic relationships among Dreissena rostriformis, D. bugensis, D. polymorpha, D. stankovici, Congeria kusceri, and Mytilopsis leucophaeata. Dreissena stankovici was determined to represent a sister taxa to D. polymorpha and both are more closely related to other extant Dreissena species than Congeria or Mytilopsis. Sequence divergence between D. rostriformis and D. bugensis was relatively low (0.3-0.4%), suggesting that these two taxa constitute a single species. However, environmental differences suggest two races of D. rostriformis, a brackish water race (rostriformis) and a freshwater race (bugensis). Spread of bugensis-type individuals into habitats in the Caspian Sea that are occupied by rostriformis-type individuals may create novel hybridization opportunities. Species-specific molecular markers also were developed in this study since significant intraspecific variation in morphological features complicates dreissenid identification. Using two gene fragments (nuclear 28S and 16S), we identified restriction fragment length polymorphisms (RFLPs) that distinguish among D. rostriformis/bugensis, D. polymorpha, and D. stankovici and revealed the presence of a cryptic invader to the Black Sea basin, Mytilopsis leucophaeata. This is the first report of this North American native in southern Europe.

  9. Population structure, biomass and production of the West African lucinid Keletistes rhizoecus (Bivalvia, Mollusca) in Sivibilagbara swamp at Bodo Creek, Niger Delta, Nigeria

    NARCIS (Netherlands)

    Zabbey, N.; Hart, A. I.; Wolff, W. J.

    2010-01-01

    The West African lucinid bivalve Keletistes rhizoecus (Oliver, Basteria 50:47-64, 1986) is only known from the Niger Delta in Nigeria. Due to inaccessibility of its habitat population biology, growth parameters, biomass, and annual secondary production are unknown. The danger of oil pollution

  10. Cell proliferation and apoptosis in gill filaments of the lucinid Codakia orbiculata (Montagu, 1808) (Mollusca: Bivalvia) during bacterial decolonization and recolonization.

    Science.gov (United States)

    Elisabeth, Nathalie H; Gustave, Sylvie D D; Gros, Olivier

    2012-08-01

    The shallow-water bivalve Codakia orbiculata which harbors gill-endosymbiotic sulfur-oxidizing γ-proteobacteria can lose and acquire its endosymbionts throughout its life. Long-term starvation and recolonization experiments led to changes in the organization of cells in the lateral zone of gill filaments. This plasticity is linked to the presence or absence of gill-endosymbionts. Herein, we propose that this reorganization can be explained by three hypotheses: (a) a variation in the number of bacteriocytes and granule cells due to proliferation or apoptosis processes, (b) a variation of the volume of these two cell types without modification in the number, and (c) a combination of both number and cell volume variation. To test these hypotheses, we analyzed cell reorganization in terms of proliferation and apoptosis in adults submitted to starvation and returned to the field using catalyzed reporter deposition fluorescence in situ hybridization, immunohistochemistry, and structural analyses. We observed that cell and tissue reorganization in gills filaments is due to a variation in cell relative abundance that maybe associated with a variation in cell apparent volume and depends on the environment. In fact, bacteriocytes mostly multiply in freshly collected and newly recolonized individuals, and excess bacteriocytes are eliminated in later recolonization stages. We highlight that host tissue regeneration in gill filaments of this symbiotic bivalve can occur by both replication of existing cells and division of undifferentiated cells localized in tissular bridges, which might be a tissue-specific multipotent stem cell zone. Copyright © 2012 Wiley Periodicals, Inc.

  11. Chaetogaster limnaei (annelida: oligochaeta) as a parasite of the zebra mussel Dreissena polymorpha, and the quagga mussel Dreissena bugensis (mollusca: bivalvia).

    Science.gov (United States)

    Conn, D B; Ricciardi, A; Babapulle, M N; Klein, K A; Rosen, D A

    1996-01-01

    Dreissenid mussels, Dreissena polymorpha and D. bugensis, were found to be infected by the naidid oligochaete Chaetogaster limnaei at four sites in the St. Lawrence River. This is the first report of this species infecting dreissenids anywhere in the world. Most worms inhabited the mantle cavity, where they caused erosion of the mantle and gill epithelia as determined by histopathological examination. Others penetrated various tissues; one had invaded the ovary and was feeding on oocytes and ovarian tissues. Of 606 mussels examined, 166 (27.4%) harbored at least 1 C. limnaei. The prevalence varied between 1% and 80%, depending on the collection site and date. The worms were slightly but significantly more prevalent in D. bugensis than in D. polymorpha. The intensity ranged from 1 to 18 worms per infected host. Variations in prevalence and intensity were not related to the size or sex of the host, but the data did suggest some seasonality.

  12. [Lipid and fatty acid profile of Perna viridis, green mussel (Mollusca: Bivalvia) in different areas of the Eastern Venezuela and the West Coast of Trinidad].

    Science.gov (United States)

    Koftayan, Tamar; Milano, Jahiro; D'Armas, Haydelba; Salazar, Gabriel

    2011-03-01

    The species Perna viridis is a highly consumed species, which fast growth makes it an interesting aquaculture alternative for Venezuelan and Trinidad coasts. With the aim to contribute with its nutritional value information, this study analyzed lipid and fatty acid contents from samples taken in five locations from Eastern Venezuela and three from Trinidad West Coast. Total lipids were extracted and quantified, from a pooled sample of 100 organisms per location, by standard gravimetric methods, and their identification and quantification was done by TLC/FID (Iatroscan system). Furthermore, the esterified fatty acids of total lipid, phospholipids and triacylglycerols were identified and quantified by gas chromatography. Eastern Venezuela samples from Los Cedros, La Brea and Chaguaramas showed the highest total lipid values of 7.92, 7.74 and 7.53, respectively, and the minimum values were obtained for La Restinga (6.08%). Among lipid composition, Chacopata samples showed the lowest phospholipid concentration (48.86%) and the maximum values for cholesterol (38.87%) and triacylglycerols (12.26%); besides, La Esmeralda and Rio Caribe samples exhibited maximum phospholipids (88.71 and 84.93 respectively) and minimum cholesterol (6.50 and 4.42%) concentrations. Saturated fatty acids represented between 15.04% and 65.55% within total lipid extracts, with maximum and minimum values for La Esmeralda and Chacopata, respectively. Polyunsaturated results resulted between 7.80 and 37.18%, with higher values in La Brea and lower values in La Esmeralda. For phospholipids, saturated fatty acids concentrations varied between 38.81 and 48.68% for Chaguaramas and Chacopata samples, respectively. In the case of polyunsaturated fatty acids, these varied between non detected and 34.51%, with high concentrations in Los Cedros (27.97%) and Chaguaramas (34.51%) samples. For the triacylglycerols, the saturated fatty acids composition oscillated between 14.27 and 53.80% with low concentrations for Chacopata and high concentration for La Restinga; the polyunsaturated fatty acids were between 4.66 and 35.55% with lower values for Chacopata and higher values for Chaguaramas samples. P. viridis is recommended for human being consumption, according to the high content of unsaturated fatty acids found for this species.

  13. Analysis of trace elements in the shells of short-necked clam Ruditapes philippinarum (Mollusca: Bivalvia) with respect to reconstruction of individual life history

    International Nuclear Information System (INIS)

    Arakawa, Jumpei; Sakamoto, Wataru

    1998-01-01

    Strontium (Sr) concentration in the shells of short-necked clams collected at different locations (Shirahama, warm area and Maizuru, cold area, Japan) was analyzed by two methods, PIXE and EPMA. The Sr concentration of external surface of shell umbo, which was made during short term at early benthic phase, was analyzed by PIXE, and was ranged from 1000 to 3500 ppm for individuals. The Sr concentration of clams collected at Shirahama showed positive correlation with shell length (SL) in individuals with SL < 31 mm, whereas clams collected at Maizuru did not show significant correlation. This result may be caused from the difference of the spawning seasons between two areas. The Sr concentration of cross section of shell umbo, which develops thicker continuously during their life to form faint stratum structure, was analyzed by EPMA along the line across the stratum structure. Some surges and long term waving patterns of the Sr concentration were observed. These results suggest that the life histories of individual clams could be recorded in the shell umbo cross sections as variations of trace elements and analyses of trace elements could clarify the histories of individual clams. (author)

  14. Occurrence, population dynamics and habitat characterization of Mytella guyanensis (Lamarck, 1819 (Mollusca, Bivalvia in the Paraíba do Norte river estuary

    Directory of Open Access Journals (Sweden)

    Alberto Kioharu Nishida

    1995-01-01

    Full Text Available A survey of Mytellaguyanensis occurrence and population dynamics were performed in the Paraíba do Norte river estuary. The characterization and the influence of temperature, salinity and substrate, as well as the associated fauna and flora on the population were also examined. Mytella guyanensis lives buried in the substrate of the mangrove intertidal zone of the Paraíba do Norte river estuary, from the mouth to 24 km upriver. Average annual density of this bivalve species was 5.2 individuals per m², with a predominantly aggregated distribution. The most frequent size was between 4.5 and 5.5 cm in length. Analysis of the substrate demonstrated the presence of two types of substrates in relation to the percentage of silt and clay and the water content. Besides interfering in the population density, the substrate heterogeneity may be a decisive factor in aggregation. Eight species of crustacean decapods and one bivalve species were identified as associated fauna.A ocorrência de M, guyanensis no estuário do Rio Paraíba do Norte foi mapeada, determinando-se sua presença ao longo dos afluentes e ilhas aí existentes. O estudo da dinâmica da população foi realizado em área protegida da Ilha da Restinga, coletando-se os animais ao longo de 37 transecções. A cada mês foram feitos 60 lançamentos com um delimitador de 0,1 m², sobre uma ou mais transecções. Todo o substrato foi retirado juntamente com os exemplares de M. guyanensis e a fauna associada, até a profundidade de 10 cm. A triagem dos exemplares menores foi feita por peneiramento do substrato. O tipo de substrato foi anotado a cada lançamento. Dois tipos de substrato estão presentes na área: um substrato de tipo consistente, constituido por 89.7% de silte e argila e 10.3% de areia fina e outro de tipo não consistente contendo 74.5% de silte e argila e 25.5% de areia fina. O substrato de tipo não consistente apresenta quantidade de água significativamente maior que o de tipo consistente. Mytella guyanensis vive enterrada no solo numa profundidade máxima de 1,0 cm, sempre envolvida pelos filamentos do bisso. A densidade média anual observada para a espécie foi de 5,2 indivíduos por m²; a distribuição espacial predominante foi do tipo agregado, sofrendo interferência do tipo de substrato presente. Houve preferência de fixação da espécie pelo substrato do tipo consistente. Animais entre 4,5 e 5,5 cm de comprimento ocorrem o ano todo, sendo mais numerosos aqueles com comprimento entre 4,5 e 5,0 cm. A presença de formas jovens foi assinalada em baixa frequência em alguns meses do ano. A salinidade da água estuarina variou de acordo com o regime pluviométrico da região, permanecendo dentro dos níveis de tolerância da espécie. A fauna associada está representada por oito espécies de crustáceos e por uma de molusco bivalve.

  15. Bioaccumulation and elimination of 60 Co and 137 Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of 60 Co, retained in marine sediment by microbial activity

    International Nuclear Information System (INIS)

    Mayr, L.M.

    1984-05-01

    It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize 60 Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of 60 Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10 -3 ). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize 60 Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For 137 Cs the determined BF from water to the animal was 2.2. and, as in the case of 60 Co, the soft tissues concentrated more 137 Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of 60 Co or 137 Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained 60 Co longer (biological half-life = 117 days) than shells, whereas for 137 Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of 60 Co and 137 Cs BF S do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by 60 Co or 137 Cs should be monitored. (author)

  16. Intra-specific variability in life-history traits of Anadara tuberculosa (Mollusca: Bivalvia) in the mangrove ecosystem of the Southern coast of Ecuador.

    Science.gov (United States)

    Flores, Luis; Licandeo, Roberto; Cubillos, Luis A; Mora, Elba

    2014-06-01

    Anadara tuberculosa is one of the most important bivalves along the Western Pacific coast because of its commercial value. Nevertheless, the variability in growth, long-life span, natural mortality and reproductive parameters of this mangrove cockle has not yet been described. The aim of this study was to analyze these life-history traits in three areas of the Southern coast of Ecuador. Empirical and length-based methods were used to estimate these biological parameters. Body size data were collected from the commercial fishery between 2004 and 2011 in landing ports near to the Archipelago of Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) and Puerto Hualtaco (PH)]. The von Bertalanffy growth parameters for combined sex were estimated between 70.87 to 93.45mm for L(infinity) and 0.22 to 0.80/year for k. The growth indices (PHI') ranged from 3.17 to 3.85, while the overall growth performance (OGP) ranged from 5.03 to 5.82. The mean of long-life span (t(max)), size and age at maturity (L50% and t50%) were estimated in 7.71 +/- 2.53 years, 39.13 +/- 2.24mm and 1.46 +/- 0.56 years for PB; 9.51 +/- 2.85 years, 37.78 +/- 1.95mm and 1.37 +/- 0.41 years for PJ and 5.81 +/- 2.11 years, 39.73 +/- 3.31mm and 0.94 +/- 0.41 years for PH. Natural mortality (M) ranged from 0.46 to 1.28/year. We concluded that significant intra-specific variation was observed in a temporal scale in PHI' and OGP indices as well as L50% and M. Therefore, temporal changes in these life-history traits should be taken into account when assessing the status of the mangrove cockle fishery.

  17. Genetic diversity and population genetic analysis of Donax vittatus (Mollusca: Bivalvia) and phylogeny of the genus with mitochondrial and nuclear markers

    Science.gov (United States)

    Fernández-Pérez, Jenyfer; Froufe, Elsa; Nantón, Ana; Gaspar, Miguel B.; Méndez, Josefina

    2017-10-01

    In this study, the genetic diversity of Donax vittatus across the Iberian Peninsula was investigated using four mitochondrial (COI, Cytb, 16S F and M types) and three nuclear (H3, 18S and 28S) genes. These same molecular markers were also sequenced in D. semistriatus and D variegatus to address the phylogenetic relationships of the species of the genus Donax common along the European coasts. Our results showed high haplotype diversity in combination with a low nucleotide diversity and a star-shaped network with a predominant haplotype, indicating a recent population expansion for the examined sampling sites of D. vittatus. Furthermore, analyses of population differentiation performed with COI mitochondrial marker, including global FST estimation and pairwise FST values, indicated the non-existence of significant genetic structure in D. vittatus of Northwest Iberian populations. Because these localities show a high genetic similarity, we suggest that D. vittatus could be a potentially alternative exploitable resource, as complement to the D. trunculus fisheries, whose natural stocks have decreased dramatically in some areas. Furthermore, we present for the first time, evidence of DUI in the clams D. vittatus and D. semistriatus.

  18. Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna Mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coast of Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiki; Catharino, Marilia G.M.; Moreira, Edson G., E-mail: danyseo@uol.com.br, E-mail: mbvascon@ipen.br, E-mail: mitiko@ipen.br, E-mail: mgcatharino@uol.com.br, E-mail: emoreira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sousa, Eduinetty C.P.M. de, E-mail: edvinett@usp.br [Universidade de Sao Paulo (IO/USP), Sao Paulo, SP (Brazil). Instituto Oceanografico. Laboratorio de Ecotoxicologia Marinha e Microfitobentos

    2013-07-01

    In this study the content of Br, Cl, K, Mg, Mn and V was evaluated in samples of Perna perna mussels collected in coastal regions of Sao Paulo (Ponta de Itaipu and Palmas Island, in Santos) subjected to anthropogenic contamination, to compare these values with those of mussels from reference site of Cocanha Beach (in Caraguatatuba). The mussels were collected seasonally from September 2008 to July 2009. They were cleaned, ground, homogenized, lyophilized and then analyzed by Instrumental Neutron Activation Analysis (INAA). The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 8 and 10 s, under a thermal neutron flux of 6.6 x 10{sup 12} n cm{sup -2} s{sup -1} in the IEA-R1 nuclear research reactor. For quality control of analytical results, certified reference materials NIST 1566b Oyster Tissue and NIST 2876 Mussel Tissue were analyzed and their results indicated good accuracy. The ranges of concentrations (dry basis) of the elements obtained in mussels collected for the four seasons of the year were: 173.80 to 358.99 mg kg{sup -1} for Br; 45658 ± 1811 to 109166 ± 824 mg kg{sup -1} for Cl; 7043 ± 856 to 12506 ± 675 mg kg{sup -1} for K; 2774 ± 211 to 5691 ± 717 mg kg{sup -1} for Mg; 7.01 ± 0.30 to 29.74 ± 3.32 mg kg{sup -1} for Mn and 0.77 ± 0.02 to 3.43 ± 0.28 mg kg{sup -1} for V. The seasonal and spatial variations of these element concentrations were in this study. (author)

  19. Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae

    Directory of Open Access Journals (Sweden)

    Emily A. Glover

    2016-09-01

    Full Text Available A new shallow water species of the lucinid bivalve Pleurolucina is described from Curaçao in the southern Caribbean Sea and compared with known species of the genus from the western Atlantic and eastern Pacific Oceans. Although confused with the Floridian species P. leucocyma, it is most similar to the eastern Pacific P. undata. As in all studied lucinids, the new species possesses symbiotic bacteria housed in the ctenidia. The shell microstructure is unusual with repeated and intercalated conchiolin layers that have sublayers of ‘tulip-shaped’ calcareous spherules. Predatory drillings by naticid gastropods frequently terminate at the conchiolin layers.

  20. On six species of marine Mollusca from suriname, four of which are new

    NARCIS (Netherlands)

    Regteren, van C.O.

    1971-01-01

    Four new species are here described in order to have their descriptions published before "Seashells of Wia Wia" by D. J. Green & R. H. Hill and the second part of my paper on the Holocene and Recent marine Mollusca of Suriname will appear. Notes are added on two species for which names are used

  1. On fossil Mollusca from the island of Mandul, East-Borneo

    NARCIS (Netherlands)

    Beets, C.

    1950-01-01

    This paper presents the results of the examination of a fairly big collection of mollusca from the island of Mandul, north of Tarakan, East-Borneo. The material was collected by Dr. Van Holst Pellekaan while investigating the geology of Mandul in the service of the “Bataafsche Petroleum

  2. Bioaccumulation and elimination of {sup 60} Co and {sup 137} Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of {sup 60} Co, retained in marine sediment by microbial activity; Bioacumulacao e eliminacao de {sup 60}Co e {sup 137}Cs por anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilizacao de {sup 60}Co retido em sedimento marinho por atividade microbiana

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, L M

    1984-05-01

    It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize {sup 60} Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of {sup 60} Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10{sup -3}). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize {sup 60} Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For {sup 137} Cs the determined BF from water to the animal was 2.2. and, as in the case of {sup 60} Co, the soft tissues concentrated more {sup 137} Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of {sup 60} Co or {sup 137} Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained {sup 60} Co longer (biological half-life = 117 days) than shells, whereas for {sup 137} Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of {sup 60} Co and {sup 137} Cs BF{sub S} do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by {sup 60} Co or {sup 137} Cs should be monitored. (author).

  3. Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil Gametogenic cycle and reproductive behavior of Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae in the Subaé river estuary, Todos os Santos Bay, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Patrícia P. Silva

    2012-12-01

    Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818 in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis, gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M and 46.3% as females (F, without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.

  4. Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil Gametogenic cycle and reproductive behavior of Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae in the Subaé river estuary, Todos os Santos Bay, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Patrícia P. Silva

    2012-01-01

    Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818 in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis, gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M and 46.3% as females (F, without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.

  5. Biocenosis de Bivalvia y Polyplacophora del intermareal rocoso en playa Tlacopanocha, Acapulco, Guerrero, México Polyplacophora and Bivalvia biocenosis at rocky intertidal Tlacopanocha beach, Acapulco, Guerrero, Mexico

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    Lizeth Galeana-Rebolledo

    2012-11-01

    Full Text Available El Estado de Guerrero, México, tiene regiones marinas prioritarias para la conservación de su biodiversidad y la información acerca de la diversidad de moluscos es escasa, por lo que es necesario realizar inventarios de especies, estudios de ecología de poblaciones y comunidades. Este estudio se efectuó en el intermareal rocoso de la playa Tlacopanocha. Los objetivos fueron: determinar la riqueza, densidad y diversidad de especies; analizar la composición de especies y estructura de tallas. El área de muestreo fue de 10 m² y la unidad de muestreó fue de 1 m². Se identificaron 35 especies, de las cuales tres son nuevos registros para el intermareal rocoso de Guerrero: las familias mejor representadas en riqueza de especies fueron Ischnochitonidae y Arcidae, y en abundancia Chitonidae y Chamidae; la densidad fue de 31,60 ind m-2. Polyplacophora presentó 42,9% de especies dominantes y Bivalvia 19,0%. Chama corallina presentó la mayor talla en longitud y Chama sordida en ancho. La riqueza de especies de moluscos registrada se considera alta y corresponde a lo esperado para un sustrato rocoso en zona tropical. Polyplacophora presentó alta composición de especies, que podría ser resultado de la adaptación de los organismos a las condiciones dinámicas del intermareal rocoso. Los nuevos registros indican la importancia de los inventarios de especies y también del conocimiento de las poblaciones y comunidades de la fauna marina de Guerrero.The State of Guerrero, Mexico, has priority marine areas for conservation of its biodiversity, but information concerning diversity of mollusks is limited, so it is convenient to carry out species inventories, studies of populations and community ecology. This study was conducted in the intertidal rocky beach Tlacopanocha. The objectives were to determine richness, density and species diversity, analyze the species composition and size structure. The sampling area was 10 m² and the sampling unit was

  6. Some fossil species of Babylonia seen in ultraviolet light, with description of a new species (Mollusca, Gastropoda)

    NARCIS (Netherlands)

    Regteren, van C.O.; Gittenberger, E.

    1972-01-01

    When preparing a revision of the genus Babylonia for "Indo-Pacific Mollusca", edited by Dr. R. Tucker Abbott, we tried ultraviolet light to see the outline of the colour-pattern of some fossil species. Later on we saw the same method described by Mrs. Katherine Krueger (1971). Dr. H. E. Coomans of

  7. The mitochondrial genome of the sipunculid Phascolopsis gouldii supports its association with Annelida rather than Mollusca

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.; Staton, Joseph

    2001-09-01

    We have determined the sequence of about half (7470 nts) of the mitochondrial genome of the sipunculid Phascolopsis gouldii, the first representative of this phylum to be so studied. All of the 19 identified genes are transcribed from the same DNA strand. The arrangement of these genes is remarkably similar to that of the oligochaete annelid Lumbricus terrestris. Comparison of both the inferred amino acid sequences and the gene arrangements of a variety of diverse metazoan taxa reveals that the phylum Sipuncula is more closely related to Annelida than to Mollusca. This requires reinterpretation of the homology of several embryological features and of patterns of animal body plan evolution.

  8. Factors driving changes in freshwater mussel (Bivalvia, Unionida) diversity and distribution in Peninsular Malaysia.

    Science.gov (United States)

    Zieritz, Alexandra; Lopes-Lima, Manuel; Bogan, Arthur E; Sousa, Ronaldo; Walton, Samuel; Rahim, Khairul Adha A; Wilson, John-James; Ng, Pei-Yin; Froufe, Elsa; McGowan, Suzanne

    2016-11-15

    Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Determination of protein-carbonyls and ubiquitin-mediated proteolysis as biomarkers of oxidative-stress in bivalvia and anthozoa

    International Nuclear Information System (INIS)

    Walker, Stephen Thomas

    2002-01-01

    This study describes the investigation of biomarkers of oxidative-stress in the bivalves Mytilus edulis and Dosinia lupinus, together with host and symbiont tissues of the scleractinian Anthozoa Agaricia agaricites. The biomarkers used were assay of total (via spectrophotometry) and individual (via Western blotting; Oxyblot kit) protein-carbonyls (PC=Os) and content of ubiquitin protein conjugates (UPC) via Western blotting (Bivalvia and Anthozoa) and immunohistochemistry (Anthozoa only). Additional assays for Bivalvia were Trolox equivalent antioxidant capacity (TEAC); and post γ-irradiation survival rates. Experimental stressors for Bivalvia were increased seawater temperature, H 2 O 2 and 60 Co γ-radiation (latter two were used in vivo and in vitro). Comparisons of clean and polluted marine sites are included. Stressors used for Anthozoa were increased solar irradiation concomitant with elevated seawater temperature. Results and conclusions were as follows: individual samples showed considerable variation, pooling of samples improved consistency. Controls for both biomarkers had detectable background levels in each phylum, against which relatively small differences were assessed. In M. edulis, no measurable differences in PC=Os could be determined when elevated seawater temperature or dilute H 2 O 2 ( 2 O 2 (30% v/v) produced a small difference. 60 Co γ-radiation produced clearer differences via Oxyblot and spectrophotometric assays. Comparison of four different tissues from the two bivalves found considerable species-specific and tissue-specific differences. Post-irradiation mortality between species was significantly different (<0.001), D. lupinus was more susceptible than M. edulis. TEAC values generally showed a decrease following irradiation (except for digestive gland). UPCs were clearly different between tissues and between species. PC=Os can be detected by DNPH-reactivity/Western blotting assay in host A. agaricites. UPCs can be assayed via Western

  10. Determination of protein-carbonyls and ubiquitin-mediated proteolysis as biomarkers of oxidative-stress in bivalvia and anthozoa

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Stephen Thomas

    2002-07-01

    This study describes the investigation of biomarkers of oxidative-stress in the bivalves Mytilus edulis and Dosinia lupinus, together with host and symbiont tissues of the scleractinian Anthozoa Agaricia agaricites. The biomarkers used were assay of total (via spectrophotometry) and individual (via Western blotting; Oxyblot kit) protein-carbonyls (PC=Os) and content of ubiquitin protein conjugates (UPC) via Western blotting (Bivalvia and Anthozoa) and immunohistochemistry (Anthozoa only). Additional assays for Bivalvia were Trolox equivalent antioxidant capacity (TEAC); and post {gamma}-irradiation survival rates. Experimental stressors for Bivalvia were increased seawater temperature, H{sub 2}O{sub 2} and {sup 60}Co {gamma}-radiation (latter two were used in vivo and in vitro). Comparisons of clean and polluted marine sites are included. Stressors used for Anthozoa were increased solar irradiation concomitant with elevated seawater temperature. Results and conclusions were as follows: individual samples showed considerable variation, pooling of samples improved consistency. Controls for both biomarkers had detectable background levels in each phylum, against which relatively small differences were assessed. In M. edulis, no measurable differences in PC=Os could be determined when elevated seawater temperature or dilute H{sub 2}O{sub 2} (<30% v/v) stressors were used, nor with between-site comparisons. Concentrated H{sub 2}O{sub 2} (30% v/v) produced a small difference. {sup 60}Co {gamma}-radiation produced clearer differences via Oxyblot and spectrophotometric assays. Comparison of four different tissues from the two bivalves found considerable species-specific and tissue-specific differences. Post-irradiation mortality between species was significantly different (<0.001), D. lupinus was more susceptible than M. edulis. TEAC values generally showed a decrease following irradiation (except for digestive gland). UPCs were clearly different between tissues and

  11. Density, size structure, shell orientation and epibiontic colonization of the fan mussel Pinna nobilis L. 1758 (Mollusca: Bivalvia in three contrasting habitats in an estuarine area of Sardinia (W Mediterranean

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    Piero Addis

    2009-03-01

    Full Text Available We investigated the spatial distribution, size structure, shell orientation and valve colonization by epibionts of the endangered Mediterranean bivalve Pinna nobilis in three continuous but different habitats in the Gulf of Oristano (Sardinia, western Mediterranean. The sampling stations chosen were: an estuarine area (E of coastal salt-marshes characterized by unvegetated sea-bottoms; and two areas in a seagrass meadow characterized by an extensive Posidonia oceanica meadow (Mw and patched mixed meadows of P. oceanica and Cymodocea nodosa (Me. We found significant differences in mean densities among stations and the highest value was found in the estuarine area. Shell orientation showed that there was uniform circular distribution of specimens in the Mw station and a unimodal distribution in the Me and E stations, where specimens were set at 0°N and 10°NNE, which is a pattern related to sea drift. Shell epibiosis displayed differences between habitats. The highest valve colonization was in the estuary, with filamentous dark algae and Ostrea edulis reaching almost 90 percent of shell coverage. This study provides new information on habitat preferences and data for assessing local populations of P. nobilis that is useful for its conservation and improving the knowledge of its ecology.

  12. Annotations to the figured scallops (Mollusca, Bivalvia, Pectinidae) in Gualtieri’s “Index Testarum Conchyliorum”, deposited in the Museo di Storia Naturale e del Territorio at Calci (Pisa, Italy)

    NARCIS (Netherlands)

    Dijkstra, H.H.

    2016-01-01

    An overview is given of the Pectinidae types present in the Gualtieri collection. In Gualtieri (1742) 46 figures (pl. 73 - 15 figs, pl. 74 - 25 figs, pl. 98 – 2 figs, and pl. 99 – 4 figs) show specimens of Pectinidae. Linnaeus (1758) referred to 10 Pectinidae species figured by Gualtieri. Of these,

  13. Freshwater Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites Within the 9-Foot Navigation Channel Project for the St. Paul District, United States Army Corps of Engineers, 1977 - 1979. Volume II. Appendices.

    Science.gov (United States)

    1980-09-10

    as caz’nata A J T R H Ligwnia recta L. subrost rat a Carunculina parva Lampsilis terea L. higginsi L. radiata siliquoidea L. ovata ventricosa Plagio ...radiata siZiquc’idea 1 1 0.?2 X L. ovata ventricosa 2 2 0. 3 Plagio Za trique tra X Arcidens con fragosus 2 2 0.3 Lasmiqona camptlcnata L. cost ata L

  14. Fresh-Water Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites within the 9-Foot Channel Navigation Project on Behalf of the U.S. Army.

    Science.gov (United States)

    1978-06-16

    Deertoe Ohovaria olivaria *Hjckorynut Glassback Eggshell Long ’Solid Actinonaias carinata *Mucket Mouket Mougat A. elipsiformie *Ellipse Liqumia recta...Catservatuls end Iited States Nepartmet of Agriculture, Soil Ctsraemtioa Service, Jeferson City* Missourl. Pp. I-ISO. Seshoala, A. V. 1941. Tapoles as

  15. Cuantificación de metales pesados en Anadara tuberculosa(Mollusca:bivalvia del estero Huaylá de Puerto Bolívar, por espectrofotometría de absorción atómica

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    Collaguazo-Collaguazo, Yadira

    2017-09-01

    Full Text Available The presence of heavy metals in bivalve molluscs implies a serious problem for the consumers health of this type of food. Therefore, the objective of the present investigation was to determine the presence of heavy metals in Anadara tuberculosa, mollusc of commercial importance at Puerto Bolívar, Ecuador. Atomic absorption spectrophotometry was the method used to quantify the concentration of heavy metals. The concentration of six metals was determined: lead (Pb, arsenic (As, mercury (Hg, cadmium (Cd, chromium (Cr and cobalt (Co. The average values obtained, expressed in mg.kg-1 were: Pb (7.52 ± 0.46; As (1.55 ± 0.14; Hg (364.38 ± 91.39; Cd (1.68 ± 0.28; Cr (3,89 ± 1,82 and Co (2,71 ± 0,34 in A. tuberculosa The results show that Pb, As, Cd, and Hg exceed the maximum permissible limits, mercury exceeds by more than 100 times the limit value. The smaller size (3-4 cm studied mollusc, has the capacity to bioaccumulate higher concentration of Pb, Cd and Cr.

  16. The Mass-Dimension Relationships in the Mussels Mytilus Galloprovincialis (Mollusca, Bivalvia from Different Phenotypical Groups in Periphyton Populations near Odessa Coast, the North-Western Part of Black Sea

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    Govorin I. A.

    2016-06-01

    Full Text Available The data of the size-mass indices in the mussels Mytilus galloprovincialis (Lamarck, 1819 from three phenotypic groups - brown, dark violet (black and “zebra” (brown with radial black stripes shells in the periphyton settlements on the concrete traverses near Odessa coast, the North-western part of Black Sea (Ukraine, in March-November 2014-2015 are presented. A comparative evaluation has been made on the relationships of total mass of the mollusks, wet and dry mass of their soft body and mass of the shells on the one hand, and the size of animals (length of its shells on the other hand, in the each of phenotypical groups from the five marine beach areas. It is shown, that in the marine areas with different degrees of isolation from the open sea by coast-protection engineering constructions, the mussels from different phenotypes have almost the same size-mass characteristics. Only the dry weight of soft animal body, which indicated to fatness of mollusk and therefore demonstrated his biological prosperity in specific hydrological conditions, can serve as a reliable criterion which can mark the shellfish habitats with different gradients of environmental factors.

  17. Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil

    Directory of Open Access Journals (Sweden)

    Patrícia P. Silva

    Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.

  18. The Upper Miocene of the Rostov Dome (Eastern Paratethys: Implication of the chronostratigraphy and bivalvia-based biostratigraphy

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    Ruban Dmitry A.

    2005-01-01

    Full Text Available The Rostov Dome is located in the south of the Russian Platform. In the Late Miocene this area was embraced by the Eastern Paratethys. The implications of a recently developed Neogene chronostratigraphy to the studied area are discussed. The Sarmatian regional stage corresponds to the upper part of the Langhian, the entire Serravalian and the lower part of the Tortonian global stages; the Maeotian regional stage corresponds to the upper part of the Tortonian and the lowermost horizons of the Messinian global stages; the Pontian regional stage corresponds to most of the Messinian and the lowermost Zanclean global stages. A first Bivalvia-based bio-stratigraphic framework is proposed for the territory of the Rostov Dome. Five biozones were established within the Serravalian-Messinian: Tapes vitalianus, Cerastoderma fittoni-Cerastoderma subfittoni, Congeria panticapaea, Congeria amygdaloides navicula and Monodacna pseudocatillus-Prosodacna schirvanica.

  19. Variações no comprimento dos indivíduos de uma população do mexilhão dourado, Limnoperna fortunei (Mollusca: Bivalvia: Mytilidae, ao longo do ano, na Praia do Veludo, Lago Guaíba, Rio Grande do Sul, Brasil Length variation over a one-year period in specimens of the golden mussel, Limnoperna fortunei (Mollusca: Bivalvia: Mytilidae from Veludo Beach, Guaíba Lake, Rio Grande do Sul, Brazil

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    Cintia P. dos Santos

    2008-09-01

    Full Text Available The individual size of Limnoperna fortunei (Dunker, 1857 was evaluated twice a month, for a year, based on samples from Veludo Beach (30º12'35"S, 51º11'68"W in Guaiba Lake, southern Porto Alegre, Brazil. Physical and chemical data on water quality, such as temperature, transparency, depth, pH, dissolved oxygen, phosphorus, nitrogen, chlorophyll "a", and conductivity were also recorded. Adult samples were collected from underwater "sarandi" branches, Cephalanthus glabratus (Spreng K. Schum (Rubiaceae, an aquatic macrophyte available at each site. Adults placed on artificial substrates were also checked every six months. Data were analyzed by applying multivariate statistics techniques related to the physical and chemical variables of the water and the density of individuals to estimate the patterns of the individual growth over the year. The adults were separated into three groups according to length classes: G1, G2 and G3 (groups 1 through 3. These three groups are related to the differences in behavior, namely, the ability of locomotion and fixation capacity. Individuals from Group 1 (5 to 7 mm in length were the most abundant and were present in all the sampled months. Adults from artificial substrates were shown to display significant differences in seasonal growth and faster growth during spring and summer months.

  20. Ross Sea Mollusca from the Latitudinal Gradient Program: R/V Italica 2004 Rauschert dredge samples

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    Claudio Ghiglione

    2013-10-01

    Full Text Available Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP on board the R/V “Italica” in the Ross Sea (Antarctica in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500µm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data. Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species, 1,323 were Bivalvia (accounting for 36 species, 949 were Aplacophora (accounting for 7 species, 74 specimens were Scaphopoda (3 species, 38 were Monoplacophora (1 species and, finally, 10 specimens were Polyplacophora (1 species. This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA, Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project “BAMBi” (PNRA 2010/A1.10.

  1. Quitones (Mollusca: Polyplacophora de El Salvador, América Central

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    Cedar I García-Ríos

    2007-03-01

    Full Text Available En El Salvador se habían registrado los poliplacóforos Chaetopleura lurida (Sowerby, 1832; Ischnochiton guatemalensis (Thiele, 1910; Ceratozona angusta (Thiele, 1909; Chiton stokesii (Broderip, 1832 y Acantochitona exquisita (Pilsbry, 1893. Recolectamos quitones en aguas someras de El Salvador en julio del 2002, agragando a la lista a Lepidochitona beanii (Carpenter, 1857; Ischnochiton dispar (Sowerby, 1832; Stenoplax limaciformis (Sowerby, 1832; Callistochiton expressus (Carpenter, 1865; Acanthochitona arragonites (Carpenter, 1867; Acanthochitona ferreirai (Lyons, 1988 y Acanthochitona hirudiniformis (Sowerby, 1832. Ampliamos la distribución documentada de I. dispar hacia el norte y describimos brevemente una especie innominada de Lepidochitona.Chitons (Mollusca: Polyplacophora from El Salvador, Central America. Collections of 11 species of shallow water Polyplacophora from El Salvador were made in July 2002. Previously only five species had been documented in El Salvador: Chaetopleura lurida (Sowerby, 1832; Ischnochiton guatemalensis (Thiele, 1910; Ceratozona angusta (Thiele, 1909; Chiton stokesii (Broderip, 1832 and Acantochitona exquisita (Pilsbry, 1893. Of these, I. guatemalensis and A. exquisita were not collected in this census. Seven other species are reported here for El Salvador for the first time: Lepidochitona beanii (Carpenter, 1857; Ischnochiton dispar (Sowerby, 1832; Stenoplax limaciformis (Sowerby, 1832; Callistochiton expressus (Carpenter, 1865; Acanthochitona arragonites (Carpenter, 1867; A. ferreirai (Lyons, 1988 and A. hirudiniformis (Sowerby, 1832. The known geographic distribution of I. dispar is extended to the north. An un-named species of Lepidochitona is briefly described. Rev. Biol. Trop. 55 (1: 171-176. Epub 2007 March. 31.

  2. Mollusca from a species-rich deep-water Leptometra community in the Alboran Sea

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    Serge Gofas

    2014-12-01

    Full Text Available An exceptional species richness for Mollusca was found on Avempace bank (349-365 m, Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens with a high Shannon-Wiener diversity index (H’(log2=3.60. The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.

  3. Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia)

    Science.gov (United States)

    Kapan, Sevinç; Kabasakal, Sinem

    2016-04-01

    Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia) Sevinç KAPAN, Sinem KABASAKAL, Çanakkale Onsekiz Mart University, Engineering Faculty, Geological Engineering Department sevinckapan_yesilyurt@hotmail.com In this study, paleontology and stratigraphy of Neogene and Quaternary units around south of the Dardanelles have been examined using Gastropoda and Bivalvia fauna. In the investigation area, the base of the sediments that belongs to Neogene, consist of the volcanics which are formed with basalts, andesites and tuff. Neogene begins unconformity with basal conglomerate which are formed with basalt and tuff gravels. The measurable thickness of the Neogene sediments is approximately 200meters in total. First fossiliferius level which consist of Lymnocardium (Euxinicardium) nobile Sabba has showed similarities with the Pontian (Late Miocene) fauna of the Eastern Paratethys. The existence of Melanopsis and Psidium species indicate that the basin has been brackish water feeding by fresh water in the Early Pliocene. Theodoxus fluviatilis (Linne), Theodoxus (Calvertia) aff. imbricata Brusina, Theodoxus (Calvertia) licherdopoli scriptus (Stefanescu), Viviparus mammatus (Stefanescu), Valvata (Valavata) sulekiana Brusina, Valvata (Cincinna) crusitensis Fontannes, Hydrobia cf grandis Cobalcescu, Hydrobia ventrosa Monfort, Melanopsis (Melanopsis) cf. bergeroni Stefanescu, , Melanopsis (Melanopsis) sandbergeri rumana Tournouer, Melanopsis (Canthidomus) hybostoma anili Taner, Melanopsis (Canthidomus) hybostoma amaradica Fontannes, Melanopsis (Canthidomus) lanceolata Neumayr, Amphimelania fossariformis (Tournouer), Melanoides tuberculata monolithica (Bukowski), Radix (Radix) peregra (Müller), Planorbarius thiollierei (Michaud), Potamida (Potamida) craiovensis craiovensis (Tournouer), Potamida (Potamida) berbestiensis (Fontannes), Unio pristinus davilai Porumbaru, Unio subexquisitus Jatzko, Anadonta zmaji

  4. The Preliminary Study of Organochlorine Pesticide Residues on Sediments of Bivalvia Fishing Ground at Eastern Part of Coastal Semarang

    Science.gov (United States)

    Adhi Suryono, Chrisna; Subagyo; Setyati, Wilis Ari; Sri Susilo, Endang; Rochaddi, Baskoro; Triaji Mahendrajaya, Robertus

    2018-02-01

    This paper presents the occurrence level of organochlorine contamination in marine sediments of Semarang coastal areas as a fishing ground of Bivalvia. Five compounds (Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT) of contaminant have been determined in the sediments surface of Semarang coastal waters. The samples were then analyzed by using gas chromatography and followed by using the method of Standard Method Examination. The result showed that the average concentration of organochlorine pesticides Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT were 25.5, bellow detected, 7.1, 37.2, 28.6 μ g/L, respectively. The high concentration of pesticide showed on Endrin (65,84 ppb), pp-DDT (29,53 μ g/L), and heptachlor (25,45 μ g/L). The low concentrations were detected on aldrin (bellow detected) and endosulfan (0,92 μ g/L). The concentration of organochlorine pesticides in these areas might contribute on four rivers which deposited the sediment in these coastal waters

  5. Comparative studies on the morphometry and physiology of European populations of the lagoon specialist Cerastoderma glaucum (Bivalvia

    Directory of Open Access Journals (Sweden)

    Katarzyna Tarnowska

    2009-09-01

    Full Text Available Seasonal changes in the morphometric and physiological parameters of the cockle Cerastoderma glaucum (Bivalvia from the Baltic Sea (GD, the North Sea (LV, and the Mediterranean Sea (BL were investigated. The cockles from GD were much smaller than those from other populations due to osmotic stress. The female to male ratios did not differ significantly from 1:1. The northern populations (GD, LV had a monocyclic reproductive pattern, whereas the southern population (BL seemed to reproduce throughout the year. Seasonal changes in the contents of biochemical components appeared to be correlated with changes in trophic conditions and the reproductive cycle. Protein content was the highest in spring for all the populations. The highest lipid contents and lowest carbohydrate contents were noted in GD and BL in spring, while no marked differences were noted among seasons in LV (probably because the data from both sexes were pooled. Respiration rates in GD were the highest among the populations, which could have been due to osmotic stress. High metabolic rates expressed by high respiration rates in GD and LV in spring and autumn could have resulted from gamete development (in spring and phytoplankton blooms (in spring and autumn.

  6. The Pleurobemini (Bivalvia: Unionida) revisited: Molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species

    Science.gov (United States)

    Inoue, Kentaro; Hayes, David M.; Harris, John L.; Johnson, Nathan A.; Morrison, Cheryl L.; Eackles, Michael S.; King, Tim; Jones, Jess W.; Hallerman, Eric M.; Christian, Alan D.; Randklev, Charles R.

    2018-01-01

    The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterization of currently unrecognized taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 573 cox1 sequences from 110 currently recognized species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognized taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g., morphology, life history, ecology) are necessary before any taxonomic changes are formalized.

  7. Homology and homoplasy of swimming behaviors and neural circuits in the Nudipleura (Mollusca, Gastropoda, Opisthobranchia)

    Science.gov (United States)

    Newcomb, James M.; Sakurai, Akira; Lillvis, Joshua L.; Gunaratne, Charuni A.; Katz, Paul S.

    2012-01-01

    How neural circuit evolution relates to behavioral evolution is not well understood. Here the relationship between neural circuits and behavior is explored with respect to the swimming behaviors of the Nudipleura (Mollusca, Gastropoda, Opithobranchia). Nudipleura is a diverse monophyletic clade of sea slugs among which only a small percentage of species can swim. Swimming falls into a limited number of categories, the most prevalent of which are rhythmic left–right body flexions (LR) and rhythmic dorsal–ventral body flexions (DV). The phylogenetic distribution of these behaviors suggests a high degree of homoplasy. The central pattern generator (CPG) underlying DV swimming has been well characterized in Tritonia diomedea and in Pleurobranchaea californica. The CPG for LR swimming has been elucidated in Melibe leonina and Dendronotus iris, which are more closely related. The CPGs for the categorically distinct DV and LR swimming behaviors consist of nonoverlapping sets of homologous identified neurons, whereas the categorically similar behaviors share some homologous identified neurons, although the exact composition of neurons and synapses in the neural circuits differ. The roles played by homologous identified neurons in categorically distinct behaviors differ. However, homologous identified neurons also play different roles even in the swim CPGs of the two LR swimming species. Individual neurons can be multifunctional within a species. Some of those functions are shared across species, whereas others are not. The pattern of use and reuse of homologous neurons in various forms of swimming and other behaviors further demonstrates that the composition of neural circuits influences the evolution of behaviors. PMID:22723353

  8. Diversidad y microestructura de quitones (Mollusca: Polyplacophora del Caribe de Costa Rica

    Directory of Open Access Journals (Sweden)

    Cedar I García-Ríos

    2011-03-01

    Full Text Available Los poliplacóforos asociados a los arrecifes de coral en la costa caribeña de Costa Rica han sido poco estudiados. El examen del cascajo de coral acumulado en el sublitoral somero, en cuatro estaciones de colección, localizadas en la Provincia de Limón reveló una diversidad de quitones mayor a la documentada. Anteriormente se habían registrado ocho especies para el Caribe costaricense: Ischnochiton erythronotus (C.B. Adams, 1845; Ischnoplax pectinata (Sowerby 1840; Stenoplax boogii (Haddon, 1886; S. purpurascens (C.B. Adams, 1845; Acanthopleura granulata (Gmelin, 1791; Chiton marmoratus Gmelin, 1791; C. tuberculatus Linnaeus, 1758; Acanthochitona rhodea (Pilsbry, 1893. Otras cinco se registran aquí por primera vez: Callistochiton portobelensis Ferreira 1976; Ischnochiton kaasi Ferreira 1987; I. pseudovirgatus Kaas 1972; Acanthochitona balesae Abbott 1954; Cryptoconchus floridanus (Dall 1889.Diversity and microstructure of quitons (Mollusca: Polyplacophora from the Caribbean of Costa Rica. The polyplacophorans of the coral reef on the Caribbean coast of Costa Rica have been insufficiently studied. The examination of coral rubble accumulated in the shallow sublitoral waters on four collection stations in Provincia Limón revealed a higher diversity of chitons than was documented. From the country eight species were previously known: Ischnochiton erythronotus (C.B. Adams 1845; Ischnoplax pectinata (Sowerby 1840; Stenoplax boogii (Haddon 1886; S. purpurascens (C.B. Adams 1845; Acanthopleura granulate (Gmelin 1791; Chiton marmoratus Gmelin 1791; C. tuberculatus Linnaeus 1758 and Acanthochitona rhodea (Pilsbry 1893. This study added five more species that are reported here for the first time: Callistochiton portobelensis Ferreira 1976; Ischnochiton kaasi Ferreira 1987; I. pseudovirgatus Kaas 1972; Acanthochitona balesae Abbott 1954 and Cryptoconchus floridanus (Dall 1889. Rev. Biol. Trop. 59 (1: 129-136. Epub 2011 March 01.

  9. Volutidae (Mollusca: Gastropoda) of the Lakhra Formation (Earliest Eocene, Sindh, Pakistan): systematics, biostratigraphy and paleobiogeography.

    Science.gov (United States)

    Merle, Didier; Pacaud, Jean-Michel; Métais, Grégoire; Bartolini, Annachiara; Lashari, Rafiq A; Brohi, Imdad A; Solangi, Sarfraz H; Marivaux, Laurent; Welcomme, Jean-Loup

    2014-06-27

    The paleobiodiversity of the Volutidae (Mollusca: Gastropoda) of the Ranikot Group (Sindh, Pakistan) and particularly of the Lakhra Formation (SBZ 5 biozone, Earliest Eocene), is reconsidered on the basis of new material collected during recent field trips. Ten new species are described (Mitreola brohii sp. nov., Lyrischapa vredenburgi sp. nov., L. brevispira sp. nov., Athleta (Volutopupa) citharopsis sp. nov., A. (Volutocorbis) lasharii sp. nov., Volutilithes welcommei sp. nov., V. sindhiensis sp. nov., Pseudaulicina coxi sp. nov., Sindhiluta lakhraensis sp. nov. and Pakiluta solangii sp. nov.) and one species is in open nomenclature (Lyria sp.). Three new genera are described: Lyriopsis gen. nov. [Volutinae, ?Lyriini, type species: Lyriopsis cossmanni (Vredenburg, 1923)], Sindhiluta gen. nov. [Volutilithinae, type species: Sindhiluta lakhraensis n. sp.] and Pakiluta gen. nov. [?Volutodermatinae, type species: Pakiluta solangii n. sp.]. Two new combinations are proposed: Lyriopsis cossmanni (Vredenburg, 1923) comb. nov. and Athleta (Volutopupa) intercrenatus (Cossmann & Pissarro, 1909) comb. nov. Lectotypes are designated for Lyria cossmanni Vredenburg, 1923, L. feddeni Vredenburg, 1923, Volutospina noetlingi Cossmann & Pissarro, 1909, V. intercrenata Cossmann & Pissarro, 1909 and Athleta (Volutocorbis) victoriae Vredenburg, 1923. With 21 species, this volutid fauna is the most diverse recorded from the Tethys Ocean during Earliest Eocene time. The assemblage is characterized by a strong turnover marked by regional speciation and the appearance of many western Tethyan invaders. Although at the species level, the assemblage documents a strong provincialism, at the genus level, the high number of shared genera between Eastern Tethyan and Old World Tethyan realms begins a phase of long-term homogeneity of volutid assemblages from the Tethyan paleobiogeographic province.

  10. The Complete Sequence of the Mitochondrial Genome of the Chamberednautilus (Mollusca: Cephalopoda)

    Energy Technology Data Exchange (ETDEWEB)

    Boore, Jeffrey L.

    2005-12-01

    Background: Mitochondria contain small genomes that arephysically separate from those of nuclei. Their comparison serves as amodel system for understanding the processes of genome evolution.Although complete mitochondrial genome sequences have been reported formore than 600 animals, the taxonomic sampling is highly biased towardvertebrates and arthropods, leaving much of the diversity yetuncharacterized. Results: The mitochondrial genome of a cephalopodmollusk, the Chambered Nautilus, is 16,258 nts in length and 59.5 percentA+T, both values that are typical of animal mitochondrial genomes. Itcontains the 37 genes that are typical for animal mtDNAs, with 15 on oneDNA strand and 22 on the other. The arrangement of these genes can bederived from that of the distantly related Katharina tunicata (Mollusca:Polyplacophora) by a switch in position of two large blocks of genes andtranspositions of four tRNA genes. There is strong skew in thedistribution of nucleotides between the two strands. There are an unusualnumber of non-coding regions and their function, if any, is not known;however, several of these demark abrupt shifts in nucleotide skew,suggesting that they may play roles in transcription and/or replication.One of the non-coding regions contains multiple repeats of a tRNA-likesequence. Some of the tRNA genes appear to overlap on the same strand,but this could be resolved if the polycistron were cleaved at thebeginning of the downstream gene, followed by polyadenylation of theproduct of the upstream gene to form a fully paired structure.Conclusions: Nautilus sp. mtDNA contains an expected gene content thathas experienced few rearrangements since the evolutionary split betweencephalopods and polyplacophorans. It contains an unusual number ofnon-coding regions, especially considering that these otherwise often aregenerated by the same processes that produce gene rearrangements. Thisappears to be yet another case where polyadenylation of mitochondrialtRNAs restores

  11. Search Help

    Science.gov (United States)

    Guidance and search help resource listing examples of common queries that can be used in the Google Search Appliance search request, including examples of special characters, or query term seperators that Google Search Appliance recognizes.

  12. First record of Stibarobdella moorei (Annelida, Hirudinea, Piscicolidae) a marine leech parasitizing Octopus bimaculatus (Mollusca: Octopodidae) from the Mexican Pacific coast

    OpenAIRE

    López-Peraza D. J.; Hernández-Rodríguez M.; Barón-Sevilla B.; Bückle-Ramírez L. F.; Grano-Maldonado M. I.

    2017-01-01

    The occurrence of the parasitic marine leech Stibarobdella moorei (Oka, 1910) (Hirudinea: Piscicolidae) along the northwest Mexican Pacific coast is described for the first time. This ectoparasite was collected from the skin of the Octopus bimaculatus (Verril, 1983) (Mollusca: Octopodidae). Stibarobdella loricata (Hardig, 1924) is synonymized with S. moorei as this species resembles other species of the genus based on tubercle patterns and the presence of papillae and a marginal fringe on the...

  13. The Pleurobemini (Bivalvia: Unionida) revisited: Molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species

    Science.gov (United States)

    Inoue, Kentaro; Hayes, David M.; Harris, John L.; Johnson, Nathan A.; Morrison, Cheryl L.; Eackles, Michael S.; King, Tim; Jones, Jess W.; Hallerman, Eric M.; Christian, Alan D.; Randklev, Charles R.

    2018-01-01

    The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterisation of currently unrecognised taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 575 cox1 sequences from 110 currently recognised species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognised taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g. morphology, life history, ecology) are necessary before any taxonomic changes are formalised.

  14. Population dynamics of freshwater oyster Etheria elliptica (Bivalvia: Etheriidae in the Pendjari River (Benin-Western Africa

    Directory of Open Access Journals (Sweden)

    Akélé G.D.

    2015-01-01

    Full Text Available Etheria elliptica (Bivalvia: Etheriidae is the only freshwater oyster occurring in Africa. The current study provides the first data on the population structure, growth, age, mortality and exploitation status of this species in the Pendjari River. E. elliptica length-frequency data were collected monthly from January to December 2009 and analyzed with FiSAT software. Population parameters including the asymptotic length (L∞ and growth coefficient (K were assessed to evaluate the stock status. The recruitment pattern was modeled with a FiSAT routine. The asymptotic length (L∞ was 14.75 cm, while the growth coefficient (K was 0.38 year-1. The growth performance index (ø′ reached 1.92. Specimens of Etheria elliptica reached a mean size of 4.66 cm and 6.41 cm at the end of one year and 1.5 years, respectively. We estimated total mortality (Z, natural mortality (M and fishing mortality (F to be 2.90 year-1, 1.16 year-1 and 1.74 year-1, respectively. The recruitment pattern was continuous over the year with one major peak event during the rainy season (July. The exploitation rate (E = 0.60 revealed that the freshwater oyster was probably facing overexploitation due to lack of a minimum limit size and also due to an increase in the harvesting effort. Therefore, efficient management methods were urgently required to conserve the species. The return of empty shells into the water to increase the recruitment surface, rotation planning among harvesting sites and the imposition of a minimum limit size were recommendations made in order to ensure the sustainable exploitation of wild stocks.

  15. On some Indo-Pacific boring endolithic Bivalvia species introduced into the Mediterranean Sea with their host – spread of Sphenia rueppelli A. Adams, 1850

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    A. ZENETOS

    2010-06-01

    Full Text Available The study of the endolithic molluscs found on/in living alien Spondylusshells collected in the Gulf of Iskenderun (Turkey brought to light three more alien bivalvia species namely Petricola hemprichi, Gastrochaena cymbium and Sphenia rueppelli. The presence of Sphenia rueppellideserves attention as it constitutes the first record of this species as living in the Mediterranean Sea. The definitive establishment and spreading of these bivalves in the basin seems to be also attested by careful analysis of specimens sampled in other southern Turkish localities and previously retained in local private collections. The present records raise some questions on the vector of arrival of the species in the Mediterranean Sea that could be strictly connected with their hosts.

  16. Random searching

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2009-01-01

    There are a wide variety of searching problems from molecules seeking receptor sites to predators seeking prey. The optimal search strategy can depend on constraints on time, energy, supplies or other variables. We discuss a number of cases and especially remark on the usefulness of Levy walk search patterns when the targets of the search are scarce.

  17. Search Patterns

    CERN Document Server

    Morville, Peter

    2010-01-01

    What people are saying about Search Patterns "Search Patterns is a delight to read -- very thoughtful and thought provoking. It's the most comprehensive survey of designing effective search experiences I've seen." --Irene Au, Director of User Experience, Google "I love this book! Thanks to Peter and Jeffery, I now know that search (yes, boring old yucky who cares search) is one of the coolest ways around of looking at the world." --Dan Roam, author, The Back of the Napkin (Portfolio Hardcover) "Search Patterns is a playful guide to the practical concerns of search interface design. It cont

  18. Personalized Search

    CERN Document Server

    AUTHOR|(SzGeCERN)749939

    2015-01-01

    As the volume of electronically available information grows, relevant items become harder to find. This work presents an approach to personalizing search results in scientific publication databases. This work focuses on re-ranking search results from existing search engines like Solr or ElasticSearch. This work also includes the development of Obelix, a new recommendation system used to re-rank search results. The project was proposed and performed at CERN, using the scientific publications available on the CERN Document Server (CDS). This work experiments with re-ranking using offline and online evaluation of users and documents in CDS. The experiments conclude that the personalized search result outperform both latest first and word similarity in terms of click position in the search result for global search in CDS.

  19. Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda in the Museum für Naturkunde, Berlin

    Directory of Open Access Journals (Sweden)

    Abraham Breure

    2013-03-01

    Full Text Available The type status is described of 96 taxa classified within the superfamily Orthalicoidea and present in the Mollusca collection of the Museum für Naturkunde der Humboldt-Universität zu Berlin. Lectotypes are designated for the following taxa: Orthalicus elegans Rolle, 1895; Bulimus maranhonensis Albers, 1854; Orthalicus nobilis Rolle, 1895; Orthalichus tricinctus Martens, 1893. Orthalicus sphinx tresmariae is introduced as new name for Zebra sphinx turrita Strebel, 1909, not Z. quagga turrita Strebel, 1909. The following synonyms are established: Zebra crosseifischeri Strebel, 1909 = Orthalicus princeps fischeri Martens, 1893; Orthalicus isabellinus Martens, 1873 = O. bensoni (Reeve, 1849; Zebra zoniferus naesiotes Strebel, 1909 = Orthalicus undatus (Bruguière, 1789; Porphyrobaphe (Myiorthalicus dennisoni pallida Strebel, 1909 = Hemibulimus dennisoni (Reeve, 1848; Zebra delphinus pumilio Strebel, 1909 = Orthalicus delphinus (Strebel, 1909; Orthalicus (Laeorthalicus reginaeformis Strebel, 1909 = Corona perversa (Swainson, 1821; Bulimus (Eurytus corticosus Sowerby III, 1895 = Plekocheilus (Eurytus stuebeli Martens, 1885. The taxon Bulimus (Eudioptus psidii Martens, 1877 is now placed within the family Sagdidae, tentatively in the genus Platysuccinea. Appendices are included with an index to all the types of Orthalicoidea extant (including those listed by Köhler 2007 and a partial list of letters present in the correspondence archives.

  20. Assessing metal contamination from construction and demolition (C&D) waste used to infill wetlands: using Deroceras reticulatum (Mollusca: Gastropoda).

    Science.gov (United States)

    Staunton, John A; Mc Donnell, Rory J; Gormally, Michael J; Williams, Chris D; Henry, Tiernan; Morrison, Liam

    2014-11-01

    Large quantities of construction and demolition waste (C&D) are produced globally every year, with little known about potential environmental impacts. In the present study, the slug, Deroceras reticulatum (Mollusca: Gastropoda) was used as the first biomonitor of metals (Ag, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Ti, Tl, V and Zn) on wetlands post infilling with construction and demolition (C&D) waste. The bioaccumulation of As, Ba, Cd, Co, Sb, Se and Tl were found to be significantly elevated in slugs collected on C&D waste when compared to unimproved pastures (control sites), while Mo, Se and Sr had significantly higher concentrations in slugs collected on C&D waste when compared to known contaminated sites (mining locations), indicating the potential hazardous nature of C&D waste to biota. Identifying exact sources for these metals within the waste can be problematic, due to its heterogenic nature. Biomonitors are a useful tool for future monitoring and impact studies, facilitating policy makers and regulations in other countries regarding C&D waste infill. In addition, improving separation of C&D waste to allow increased reuse and recycling is likely to be effective in reducing the volume of waste being used as infill, subsequently decreasing potential metal contamination.

  1. Comunidades de quitones (Mollusca: Polyplacophora de la Bahía de La Paz, Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Cedar I García Ríos

    2007-03-01

    Full Text Available A las ocho especies de poliplacóforos registradas en Bahía de la Paz, Baja California Sur, México, o cerca de ella, agregamos a Lepidochitona beanii, Chaetopleura lurida, Stenoplax limaciformis, S. mariposa, Lepidozona clathrata, L. serrata y Acanthochitona arragonites. El análisis de las comunidades estudiadas usando técnicas de ordenación sugiere que podría relacionarse la exposición al oleaje con la riqueza y la diversidad de especies. La comunidad recolectada en condiciones intermedias de exposición al oleaje presentó mayor número de especies y mayor diversidad de acuerdo con el índice de Shannon.Polyplacophoran communities (Mollusca: Polyplacophora at Bahía de La Paz, Baja California Sur, México. Eight species of polyplacophorans have been reported from La Bahía de la Paz, Baja California Sur, Mexico. We add Lepidochitona beanii, Chaetopleura lurida, Stenoplax limaciformis, S. mariposa, Lepidozona clathrata, L. serrata and Acanthochitona arragonites, increasing the known number of species to 15. Ordination analysis of five chiton communities at the site suggests a correlation of wave exposure to species composition and diversity: communities with intermediate wave exposure have more species (richness and higher diversity (Shannon’s index. Rev. Biol. Trop. 55 (1: 177-182. Epub 2007 March. 31.

  2. Biochemical profile of Achatina fulica (Mollusca: Gastropoda) after infection by different parasitic loads of Angiostrongylus cantonensis (Nematoda, Metastrongylidae).

    Science.gov (United States)

    Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Amaral, Ludimila Santos; Mota, Esther Maria; Maldonado Júnior, Arnaldo; Pinheiro, Jairo; Garcia, Juberlan

    2015-01-01

    The effect of experimental infection by different parasitic loads of Angiostrongylus cantonensis (Nematode, Metastrongylidae) on the activities of the aminotransferases and concentration of total proteins, uric acid and urea in the hemolymph of Achatina fulica (Mollusca, Gastropoda) were investigated. There was a significant decrease in the concentration of total proteins in the exposed snails to 5000 or more larvae. This change was accompanied by an increase in the concentrations of urea and uric acid in the hemolymph, suggesting a higher rate of deamination of the amino acids. Besides this, variations in the activities of the aminotransferases were also observed, with the highest values recorded in the groups exposed to greater parasite load. These results suggest an increase in the use of total proteins, since there was increased formation of nitrogenous catabolites, in conformity with an increase in the aminotransferase activities. Infection was verified by the fact that L3 larvae recovered from the snails was proportion to the exposure dose of L1 larvae. Histopathological results also indicated presence of an inflammatory cell infiltrate, favoring an increase of both transaminases. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda) in the Museum für Naturkunde, Berlin.

    Science.gov (United States)

    Breure, Abraham S H

    2013-01-01

    The type status is described of 96 taxa classified within the superfamily Orthalicoidea and present in the Mollusca collection of the Museum für Naturkunde der Humboldt-Universität zu Berlin. Lectotypes are designated for the following taxa: Orthalicus elegans Rolle, 1895; Bulimus maranhonensis Albers, 1854; Orthalicus nobilis Rolle, 1895; Orthalichus tricinctus Martens, 1893. Orthalicus sphinx tresmariae is introduced as new name for Zebra sphinx turrita Strebel, 1909, not Zebra quagga turrita Strebel, 1909. The following synonyms are established: Zebra crosseifischeri Strebel, 1909 = Orthalicus princeps fischeri Martens, 1893; Orthalicus isabellinus Martens, 1873 = Orthalicus bensoni (Reeve, 1849); Zebra zoniferus naesiotes Strebel, 1909 = Orthalicus undatus (Bruguière, 1789); Porphyrobaphe (Myiorthalicus) dennisoni pallida Strebel, 1909 = Hemibulimus dennisoni (Reeve, 1848); Zebra delphinus pumilio Strebel, 1909 = Orthalicus delphinus (Strebel, 1909); Orthalicus (Laeorthalicus) reginaeformis Strebel, 1909 = Corona perversa (Swainson, 1821); Bulimus (Eurytus) corticosus Sowerby III, 1895 = Plekocheilus (Eurytus) stuebeli Martens, 1885. The taxon Bulimus (Eudioptus) psidii Martens, 1877 is now placed within the family Sagdidae, tentatively in the genus Platysuccinea. Appendices are included with an index to all the types of Orthalicoidea extant (including those listed by Köhler 2007) and a partial list of letters present in the correspondence archives.

  4. ON THE PALEOFAUNA INVERTEBRATES (MOLLUSCA, ARTROPODA; INSECTA OF DIATOMITE DEPOSITS OF SHAMB–1 LOCALITY (SISIAN SUITE, EARLY PLEISTOCENE, ARMENIA

    Directory of Open Access Journals (Sweden)

    М. A. Маrjanyan

    2016-01-01

    Full Text Available Aim. The study of fossil insects from diatomaceous sediments of Shamb-1 locality of Sisian Suite (Early Pleistocene. The collection of fossils plants and animals of Institute of Botany of NAS RA and authors' findings served as material for study.Methods. The material is processed and prepared for study by conventional methods in paleontology for prints and fossils of insects from diatomaceous sediments. There are 654 samples studied: 2 samples were with mollusks’ imprints and 652 samples with imprints of insects, from which preserved marks on 291samples allowed to identify them up to order, family, genus and species.Results. The studied material refers to the Mollusca and Arthropoda (Insecta types. Insects are represented by species of orders Orthoptera (2 fam., Homoptera (1 fam., Heteroptera (2 fam., Coleoptera (15 fam., Hymenoptera (2 fam., Diptera (1 fam.. Coleopteras dominate among them and are presented with following species of the family – Carabidae, Dytiscidae, Hydrophilidae, Histeridae, Staphylinidae, Silphidae, Elateridae, Buprestidae, Lampyridae, Scarabaeidae, Chrysomelidae, Tenebrionidae, Coccinellidae, Cerambycidae, Curculionidae.Main conclusions. An analysis of the taxonomic composition of paleofauna was done, which corresponds to the recent fauna and with considering modern ecological characteristics of systematical groups and species. In the investigated location of Shamb-1 a version is suggested about the palaeolandscapes and palaeoclimate in the Early Pleistocene.

  5. Search Advertising

    OpenAIRE

    Cornière (de), Alexandre

    2016-01-01

    Search engines enable advertisers to target consumers based on the query they have entered. In a framework with horizontal product differentiation, imperfect product information and in which consumers incur search costs, I study a game in which advertisers have to choose a price and a set of relevant keywords. The targeting mechanism brings about three kinds of efficiency gains, namely lower search costs, better matching, and more intense product market price-competition. A monopolistic searc...

  6. Faceted Search

    CERN Document Server

    Tunkelang, Daniel

    2009-01-01

    We live in an information age that requires us, more than ever, to represent, access, and use information. Over the last several decades, we have developed a modern science and technology for information retrieval, relentlessly pursuing the vision of a "memex" that Vannevar Bush proposed in his seminal article, "As We May Think." Faceted search plays a key role in this program. Faceted search addresses weaknesses of conventional search approaches and has emerged as a foundation for interactive information retrieval. User studies demonstrate that faceted search provides more

  7. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca.

    Science.gov (United States)

    Wiklund, Helena; Taylor, John D; Dahlgren, Thomas G; Todt, Christiane; Ikebe, Chiho; Rabone, Muriel; Glover, Adrian G

    2017-01-01

    We present the first DNA taxonomy publication on abyssal Mollusca from the Clarion-Clipperton Zone (CCZ), central Pacific ocean, using material collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area 'UK-1' in the eastern CCZ. This is the third paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Taxonomic data are presented for 21 species from 42 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 3 heterodont bivalves, 5 protobranch bivalves, 4 pteriomorph bivalves, 1 caudofoveate, 1 monoplacophoran, 1 polyplacophoran, 4 scaphopods and 2 solenogastres. Gastropoda were recovered but will be the subject of a future study. Seven taxa matched published morphological descriptions for species with deep Pacific type localities, and our sequences provide the first genetic data for these taxa. One taxon morphologically matched a known cosmopolitan species but with a type locality in a different ocean basin and was assigned the open nomenclature ' cf ' as a precautionary approach in taxon assignments to avoid over-estimating species ranges. One taxon is here described as a new species, Ledella knudseni sp. n. For the remaining 12 taxa, we have determined them to be potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

  8. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca

    Directory of Open Access Journals (Sweden)

    Helena Wiklund

    2017-10-01

    Full Text Available We present the first DNA taxonomy publication on abyssal Mollusca from the Clarion-Clipperton Zone (CCZ, central Pacific ocean, using material collected as part of the Abyssal Baseline (ABYSSLINE environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL polymetallic-nodule exploration area ‘UK-1’ in the eastern CCZ. This is the third paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Taxonomic data are presented for 21 species from 42 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 3 heterodont bivalves, 5 protobranch bivalves, 4 pteriomorph bivalves, 1 caudofoveate, 1 monoplacophoran, 1 polyplacophoran, 4 scaphopods and 2 solenogastres. Gastropoda were recovered but will be the subject of a future study. Seven taxa matched published morphological descriptions for species with deep Pacific type localities, and our sequences provide the first genetic data for these taxa. One taxon morphologically matched a known cosmopolitan species but with a type locality in a different ocean basin and was assigned the open nomenclature ‘cf’ as a precautionary approach in taxon assignments to avoid over-estimating species ranges. One taxon is here described as a new species, Ledella knudseni sp. n. For the remaining 12 taxa, we have determined them to be potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

  9. Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. Autonomous search

    CERN Document Server

    Hamadi, Youssef; Saubion, Frédéric

    2012-01-01

    Autonomous combinatorial search (AS) represents a new field in combinatorial problem solving. Its major standpoint and originality is that it considers that problem solvers must be capable of self-improvement operations. This is the first book dedicated to AS.

  11. Determination of shell deposition rates of Arctica islandica from the New York Bight using natural 228Ra and 228Th and bomb-produced 14C

    International Nuclear Information System (INIS)

    Turekian, K.K.; Cochran, J.K.; Nozaki, Y.; Thompson, I.; Jones, D.S.

    1982-01-01

    Shell deposition rates of specimens of Arctica islandica (Mollusca: Bivalvia) from the New York Bight were determined using natural 228 Ra and 228 Th and bomb 14 C. The specimens from deep (>55 m) offshore waters show annual growth banding. A shell obtained from the inner bight at <30-m depth seems to be younger than indicated by band counting

  12. The role of host specificity in explaining the invasion success of the freshwater mussel Anodonta woodiana in Europe

    Czech Academy of Sciences Publication Activity Database

    Douda, K.; Vrtílek, Milan; Slavík, O.; Reichard, Martin

    2012-01-01

    Roč. 14, č. 1 (2012), s. 127-137 ISSN 1387-3547 R&D Projects: GA AV ČR KJB600930802 Institutional research plan: CEZ:AV0Z60930519 Keywords : aquatic habitat * Bivalvia * host-parasite relationship * host specificity * Mollusca Subject RIV: EG - Zoology Impact factor: 2.509, year: 2012

  13. First record of Stibarobdella moorei (Annelida, Hirudinea, Piscicolidae a marine leech parasitizing Octopus bimaculatus (Mollusca: Octopodidae from the Mexican Pacific coast

    Directory of Open Access Journals (Sweden)

    López-Peraza D. J.

    2017-12-01

    Full Text Available The occurrence of the parasitic marine leech Stibarobdella moorei (Oka, 1910 (Hirudinea: Piscicolidae along the northwest Mexican Pacific coast is described for the first time. This ectoparasite was collected from the skin of the Octopus bimaculatus (Verril, 1983 (Mollusca: Octopodidae. Stibarobdella loricata (Hardig, 1924 is synonymized with S. moorei as this species resembles other species of the genus based on tubercle patterns and the presence of papillae and a marginal fringe on the oral sucker. The present finding throws new light on the biodiversity and host preference of the ectoparasite and suggests a successful migration to unusual host. The coast of the Pacific Ocean, particularly in the Bay of Los Angeles, Baja California, Mexico is a new geographical distribution area for S. moorei, and O. bimaculatus is a new host reported for this leech. The morphology of this ectoparasite is briefly described.

  14. Search strategies

    Science.gov (United States)

    Oliver, B. M.

    Attention is given to the approaches which would provide the greatest chance of success in attempts related to the discovery of extraterrestrial advanced cultures in the Galaxy, taking into account the principle of least energy expenditure. The energetics of interstellar contact are explored, giving attention to the use of manned spacecraft, automatic probes, and beacons. The least expensive approach to a search for other civilizations involves a listening program which attempts to detect signals emitted by such civilizations. The optimum part of the spectrum for the considered search is found to be in the range from 1 to 2 GHz. Antenna and transmission formulas are discussed along with the employment of matched gates and filters, the probable characteristics of the signals to be detected, the filter-signal mismatch loss, surveys of the radio sky, the conduction of targeted searches.

  15. Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda from Lebanon

    Directory of Open Access Journals (Sweden)

    F. CROCETTA

    2013-07-01

    Full Text Available A reviewed knowledge of the opisthobranch species from Lebanon (eastern Mediterranean Sea, based on literature records (scattered throughout various papers published over a period of more than 150 years and recently collected material (1999-2002 within the CEDRE framework and other samples, is presented, yielding a total number of 35 taxa recorded from the Lebanese shores identified to species level. Special emphasis has mainly been given to the alien species, for which scattered notes are also given. The known opisthobranch biota is composed of 22 native (~ 63%, 12 alien (~ 34% and one cryptogenic (~ 3% taxa. Eleven of these (Berthella aurantiaca, B. ocellata, Aplysia fasciata, Felimare picta, Felimida britoi, F. luteorosea, F. purpurea, Phyllidia flava, Dendrodoris grandiflora, D. limbata and Aeolidiella alderi constitute new records for the Lebanese fauna, whilst the examined material of a further seven species (Elysia grandifolia, Pleurobranchus forskalii, Aplysia dactylomela, Bursatella leachii, Syphonota geographica, Goniobranchus annulatus, Flabellina rubrolineata anecdotally cited from Lebanon on the basis of the samples here studied, is here first explained. One additional taxon belonging to the genus Haminoea has been identified to genus level only. Despite the searching effort poning the basis of the material analyzed here, data reported clearly suggest that strong investments are still needed for a better understanding of the eastern Mediterranean opisthobranch fauna.

  16. Internet Search Engines

    OpenAIRE

    Fatmaa El Zahraa Mohamed Abdou

    2004-01-01

    A general study about the internet search engines, the study deals main 7 points; the differance between search engines and search directories, components of search engines, the percentage of sites covered by search engines, cataloging of sites, the needed time for sites appearance in search engines, search capabilities, and types of search engines.

  17. Relación entre las capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en la Bahía de la Paz, Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Mariana Vázquez Hurtado

    2011-03-01

    Full Text Available La almeja chocolate Megapitaria squalida es un recurso pesquero con creciente importancia en el noroeste de México al registrarse un incremento en los volúmenes de captura. Sin embargo, esta pesquería ha observado variaciones importantes en las capturas que podrían estar relacionadas con factores ambientales. Se obtuvieron datos mensuales de producción de M. squalida durante 2002- 2005 y se estimaron series de tiempo de temperatura superficial del mar en la Bahía de La Paz B.C.S. a partir de imágenes mensuales derivadas del sensor MODIS-Aqua. Los resultados indican una relación positiva significativa entre la temperatura superficial del mar y los volúmenes de captura, razón por la cual nuestro trabajo tiene como objetivo estudiar las relaciones entre capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en La Bahía de la Paz, Baja California Sur, México.Megapitaria squalida (Bivalvia: Veneridae fishery landings and temperature relationship in Bahía de la Paz, México. The clam Megapitaria squalida is a fishing resource with increasing importance in Northwestern Mexico. Nevertheless, this fishery has shown important variations that could be related to environmental factors. To assess this, monthly landings of M. squalida were analyzed during 2002-2005 for Bahía de La Paz, B.C.S., and were related with monthly time series of sea surface temperature, derived from MODIS-Aqua Sensor. The results showed a positive and significant relationship between sea surface temperature and clam landings. The likely impact of anomalous conditions of sea temperature on this resource is discussed. Rev. Biol. Trop. 59 (1: 151-157. Epub 2011 March 01.

  18. Impact of zebra and quagga mussels (Dreissena spp.) on freshwater unionids (Bivalvia: Unionidae) in the Detroit River of the Great Lakes

    Science.gov (United States)

    Schloesser, D.W.; Kovalak, W.P.; Longton, G.D.; Ohnesorg, K.L.; Smithee, R.D.

    1998-01-01

    To assess the impact of zebra and quagga mussel (Dreissena spp.) infestation on unionids, unionids (Bivalvia: Unionidae) were sampled in the Detroit River in 1982-1983, before mussels invaded the river, and in 1992 and 1994, after mussels invaded the river. Live unionids at four stations along the southeastern shore accounted for 97% (20 species) of all shells collected in 1982-1983, whereas live unionids accounted for only 10% (13 species) in 1992. A similar decline in live unionids occurred at nine stations along the northwestern shore, except the decline occurred over the three sampling periods: in 1982-83, 84% (22 species) were live; in 1992, 65% (26 species) were live; and, in 1994, only 3% (13 species) were live. The difference in time to near-total mortality of unionids along the southeastern and northwestern shores is attributed to differences in the time of invasion and abundance of zebra mussel veligers in distinct water masses emanating from Lake St. Clair located immediately upstream of the Detroit River. Although individuals of all species of all unionid subfamilies declined between 1982 and 1992/1994, members of the subfamilies Anodontinae and Lampsilinae declined more than Ambleminae. Between 1986 and 1992/1994, five Anodontinae, three Lampsilinae and 0 Ambleminae species have been extirpated from the river due to dreissenid mussel infestation. Numbers of individuals of commonly found species declined more than numbers of individuals of uncommonly found species. However, the number of uncommon species declined 47% (17 to 9) along both the southeastern and northwestern shores, whereas common species remained the same (3 species) along the southeastern shore and declined only 40% (5 to 3 species) along the northwestern shore. This study, and others, suggest that high mortality of unionids can occur between 4 and 6 yr after initial invasion by dreissenids or up to 8 yr depending on water current patterns. Infestation-induced mortality of unionids in the

  19. Meta Search Engines.

    Science.gov (United States)

    Garman, Nancy

    1999-01-01

    Describes common options and features to consider in evaluating which meta search engine will best meet a searcher's needs. Discusses number and names of engines searched; other sources and specialty engines; search queries; other search options; and results options. (AEF)

  20. Variación estacional de la composición proximal del mejillón Tagelus peruvianus (Bivalvia: Solecurtidae del Golfo de Nicoya, Puntarenas, Costa Rica

    Directory of Open Access Journals (Sweden)

    Cristian Fonseca Rodríguez

    2011-12-01

    Full Text Available La extracción del mejillón Tagelus peruvianus representa una actividad económica complementaria de los pescadores artesanales, es una de las especies de mayor pesca y consumo ya que son una fuente importante de proteína, minerales y vitaminas esenciales para la población humana. Por lo tanto, se estudió la variación estacional de su composición proximal, índice de condición y contenido energético. Mensualmente, entre noviembre de 2007 y octubre de 2008, se recolectaron de 35 a 40 especímenes. La composición proximal se determinó siguiendo la metodología recomendada por la AOAC. Los resultados mostraron que el índice de condición disminuyó en los meses de diciembre, enero y mayo, lo que indica que hay dos periodos de desove y una fase de reposo gonadal. El componente principal del mejillón es la proteína (61.9±4.3%, seguido de carbohidratos (15.7±2.4%, cenizas (14.0±1.9% y lípidos (8.5±1.7%. El contenido calórico promedio fue de 5.0±0.1kcal/g. La disminución en los valores de proteínas, lípidos y calorías coinciden con los periodos de desove. Se puede concluir que T. peruvianus presenta valores nutricionales óptimos para el consumo humano, por su bajo contenido de grasa y su aceptable contenido proteico.Seasonal variation in proximate composition of mussels Tagelus peruvianus (Bivalvia: Solecurtidae from the Gulf of Nicoya, Puntarenas, Costa Rica. Marine bivalves are a very important food source for human consumption, and species that has not been of traditional use as a fishery resource are gaining interest. Seasonal variation in proximate composition, condition index and energy or caloric content of the mussel Tagelus peruvianus were studied in the Gulf of Nicoya, Puntarenas, Costa Rica. From November 2007 to October 2008, a total of 35 to 40 specimens per month were collected. The proximate composition using the AOAC methods was determined. Results showed that the condition index during December, January and May

  1. Efecto de bacterias probióticas en el cultivo larvario del ostión de placer Crassostrea corteziensis (Bivalvia: Ostreidae

    Directory of Open Access Journals (Sweden)

    Angel Isidro Campa-Córdova

    2011-03-01

    Full Text Available El ostión de placer u ostra del Cortés (Crassostrea corteziensis se considera como una especie con potencial para ser cultivada en gran escala. Sin embargo, al igual que en otros bivalvos, la alta mortalidad que se presenta durante la etapa larvaria y juvenil, es el principal problema que limita el desarrollo del cultivo en el laboratorio. Un método que está ganando aceptación en la acuicultura es el uso de bacterias probióticas para controlar patógenos microbianos. Este estudio analiza el efecto de estas bacterias en la supervivencia y talla final de larvas de ostión de placer Crassostrea corteziensis. Se utilizó una cepa de bacterias ácido lácticas (cepa NS61 aisladas N. subnodosus, así como de bacilos aislados de L. vannamei (Pseudomonas aeruginosa, cepa YC58 y de C. corteziensis (Burkholderia cepacia, cepa Y021. Las cepas se evaluaron por inmersión en cultivos larvarios de C. corteziensis a dos concentraciones diferentes, hasta completar el estadio pediveliger. Los organismos se trataron con bacterias ácido lácticas (Lb, una mezcla de bacilos (Lb en proporción 1:1 y un grupo control. La concentración de 1x10(4UFC/ml registró una mayor supervivencia con Lb y Mb respecto al grupo control. La supervivencia con Mb a una concentración de 1x10(5UFC/ml fue mayor que la del grupo control y del grupo tratado con Lb. Los resultados mostraron que las larvas de C. corteziensis tratadas con probióticos no incrementaron significativamente su talla respecto a las larvas del grupo control. Mientras que las tratadas con Lb a la concentración mayor, 1x10(5UFC/ml, mostraron una disminución de la supervivencia respecto a las tratadas con 1x10(4UFC/ml. Este estudio demostró el efecto benéfico de cepas probióticas utilizadas individualmente o en mezcla en el cultivo larvario de C. corteziensis.Effect of probiotic bacteria on survival and growth of Cortez oyster larvae, Crassostrea corteziensis (Bivalvia: Ostreidae. Disease control

  2. Seasonal variation in larval density of Limnoperna fortunei (Bivalvia, Mytilidae in the Iguaçu and Paraná rivers, in the region of Foz do Iguaçu, Paraná, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Débora Pestana

    2008-06-01

    Full Text Available The larval density of the invasive mussel Limnoperna fortunei (Bivalvia, Mytilidae was monitored from January 2005 to February 2006 at two points along the Paraná and the Iguaçu Rivers, near Foz do Iguaçu, PR, Brazil. The results indicated two density peaks in the Paraná River: a lower peak between March and June and a higher peak in October. In the Iguaçu River, the values were much lower, yet they also showed a peak between September and October. A reduction in the reproductive activity was observed in both the rivers between July and August. The average larval density at the collection point in the Paraná reached 948.5 larvae/m³, with a peak of 2,999.5 larvae/m³ in October. The present study represented the first quantification of the larval density of L. fortunei in the lower reaches of the Iguaçu River, downstream of the Iguaçu falls.A densidade larval do molusco invasor Limnoperna fortunei (Bivalvia, Mytilidae foi monitorada entre janeiro de 2005 e fevereiro de 2006 em dois pontos dos rios Paraná e Iguaçu, na região de Foz do Iguaçu, PR. Os resultados registraram dois picos de densidade no rio Paraná: entre março e junho e um maior em outubro. No rio Iguaçu, os valores foram muito inferiores, mas também com um pico entre setembro-outubro. Em ambos os rios foi verificada uma pausa reprodutiva entre os meses de julho-agosto. A densidade média de larvas de L. fortunei no ponto amostrado no rio Paraná chegou a 948.5 larvas/m³, com pico de 2.999,5 larvas/m³ em outubro. O presente estudo representa a primeira quantificação da densidade larval de L. fortunei no rio Iguaçu, a jusante das Cataratas do Iguaçu.

  3. Megafauna of the UKSRL exploration contract area and eastern Clarion-Clipperton Zone in the Pacific Ocean: Annelida, Arthropoda, Bryozoa, Chordata, Ctenophora, Mollusca.

    Science.gov (United States)

    Amon, Diva J; Ziegler, Amanda F; Drazen, Jeffrey C; Grischenko, Andrei V; Leitner, Astrid B; Lindsay, Dhugal J; Voight, Janet R; Wicksten, Mary K; Young, Craig M; Smith, Craig R

    2017-01-01

    There is growing interest in mining polymetallic nodules from the abyssal Clarion-Clipperton Zone (CCZ) in the tropical Pacific Ocean. Despite having been the focus of environmental studies for decades, the benthic megafauna of the CCZ remain poorly known. To predict and manage the environmental impacts of mining in the CCZ, baseline knowledge of the megafauna is essential. The ABYSSLINE Project has conducted benthic biological baseline surveys in the UK Seabed Resources Ltd polymetallic-nodule exploration contract area (UK-1). Prior to ABYSSLINE research cruises in 2013 and 2015, no biological studies had been done in this area of the eastern CCZ. Using a Remotely Operated Vehicle and Autonomous Underwater Vehicle (as well as several other pieces of equipment), the megafauna within the UK Seabed Resources Ltd exploration contract area (UK-1) and at a site ~250 km east of the UK-1 area were surveyed, allowing us to make the first estimates of megafaunal morphospecies richness from the imagery collected. Here, we present an atlas of the abyssal annelid, arthropod, bryozoan, chordate, ctenophore and molluscan megafauna observed and collected during the ABYSSLINE cruises to the UK-1 polymetallic-nodule exploration contract area in the CCZ. There appear to be at least 55 distinct morphospecies (8 Annelida, 12 Arthropoda, 4 Bryozoa, 22 Chordata, 5 Ctenophora, and 4 Mollusca) identified mostly by morphology but also using molecular barcoding for a limited number of animals that were collected. This atlas will aid the synthesis of megafaunal presence/absence data collected by contractors, scientists and other stakeholders undertaking work in the CCZ, ultimately helping to decipher the biogeography of the megafauna in this threatened habitat.

  4. How doctors search

    DEFF Research Database (Denmark)

    Lykke, Marianne; Price, Susan; Delcambre, Lois

    2012-01-01

    Professional, workplace searching is different from general searching, because it is typically limited to specific facets and targeted to a single answer. We have developed the semantic component (SC) model, which is a search feature that allows searchers to structure and specify the search to co...

  5. Sound Search Engine Concept

    DEFF Research Database (Denmark)

    2006-01-01

    Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

  6. Web Search Engines

    OpenAIRE

    Rajashekar, TB

    1998-01-01

    The World Wide Web is emerging as an all-in-one information source. Tools for searching Web-based information include search engines, subject directories and meta search tools. We take a look at key features of these tools and suggest practical hints for effective Web searching.

  7. submitter Searches at LEP

    CERN Document Server

    Kawagoe, Kiyotomo

    2001-01-01

    Searches for new particles and new physics were extensively performed at LEP. Although no evidence for new particle/physics was discovered, the null results set very stringent limits to theories beyond the standard model. In this paper, searches at LEP and anomalies observed in the searches are presented. Future prospect of searches at the new energy frontier machines is also discussed.

  8. Myanmar Language Search Engine

    OpenAIRE

    Pann Yu Mon; Yoshiki Mikami

    2011-01-01

    With the enormous growth of the World Wide Web, search engines play a critical role in retrieving information from the borderless Web. Although many search engines are available for the major languages, but they are not much proficient for the less computerized languages including Myanmar. The main reason is that those search engines are not considering the specific features of those languages. A search engine which capable of searching the Web documents written in those languages is highly n...

  9. Ordered Consumer Search

    OpenAIRE

    Armstrong, Mark

    2016-01-01

    The paper discusses situations in which consumers search through their options in a deliberate order, in contrast to more familiar models with random search. Topics include: network effects (consumers may be better off following the same search order as other consumers); the use of price and non-price advertising to direct search; the impact of consumers starting a new search with their previous supplier; the incentive sellers have to merge or co-locate with other sellers; and the incentive a...

  10. Relación entre las capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en la Bahía de la Paz, Baja California Sur, México

    Directory of Open Access Journals (Sweden)

    Mariana Vázquez Hurtado

    2011-03-01

    Full Text Available La almeja chocolate Megapitaria squalida es un recurso pesquero con creciente importancia en el noroeste de México al registrarse un incremento en los volúmenes de captura. Sin embargo, esta pesquería ha observado variaciones importantes en las capturas que podrían estar relacionadas con factores ambientales. Se obtuvieron datos mensuales de producción de M. squalida durante 2002- 2005 y se estimaron series de tiempo de temperatura superficial del mar en la Bahía de La Paz B.C.S. a partir de imágenes mensuales derivadas del sensor MODIS-Aqua. Los resultados indican una relación positiva significativa entre la temperatura superficial del mar y los volúmenes de captura, razón por la cual nuestro trabajo tiene como objetivo estudiar las relaciones entre capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en La Bahía de la Paz, Baja California Sur, México.

  11. The Search Performance Evaluation and Prediction in Exploratory Search

    OpenAIRE

    LIU, FEI

    2016-01-01

    The exploratory search for complex search tasks requires an effective search behavior model to evaluate and predict user search performance. Few studies have investigated the relationship between user search behavior and search performance in exploratory search. This research adopts a mixed approach combining search system development, user search experiment, search query log analysis, and multivariate regression analysis to resolve the knowledge gap. Through this study, it is shown that expl...

  12. Ciclo reproductivo del ostión de manglar Crassostrea rhizophorae (Bivalvia: Ostreidae en la Bahía de Camamu, Bahia, Brasil

    Directory of Open Access Journals (Sweden)

    Tiago Lenz

    2011-03-01

    Full Text Available El ostión de manglar es un importante recurso pesquero que se distribuye por toda la costa brasileña y una de las especies nativas con mayor potencial para maricultura. Este estudio tuvo como objetivo conocer las características reproductivas del ostión de manglar Crassostrea rhizophorae en el estero del Río Maraú, Bahía de Camamu, Bahia, Brasil. Las muestras fueran recolectadas mensualmente, entre agosto de 2006 y septiembre de 2007, en dos sitios. Las metodologías utilizadas fueron el análisis histológico de las gónadas y el cálculo de rendimiento de carne. La temperatura del agua durante el período de estudio varió de 23.5°C a 30°C y la salinidad osciló entre 15 y 35ups. La altura de los ostiones examinados varió de 27 a 102mm (n=437. Hubo predominancia de hembras en las poblaciones de ambos sitios. Los análisis de estadios gonádicos demostraron que el proceso de reproducción de C. rhizophorae en el estero del Río Maraú es continuo durante el año, sin período de reposo sexual. El rendimiento de carne (R fue de 8.0% a 17.7% (n=669. Los resultados de este estudio proveen informaciones para la captación de semilla e implantación de la ostricultura en la Bahía de Camamu.Reproductive cycle of the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae in Camamu Bay, Bahia, Brasil. The mangrove oyster Crassostrea rhizophorae is important fishery resource along the entire Brasilian coast with excellent potential for marine culture. The purpose of this paper was to examine the reproductive characteristics of the oyster of the Maraú river estuary in Camamu Bay, Bahia, Brasil. The samples were collected monthly, from September 2006 to August 2007, at two points (I and II in Camamu Bay. At each site 20 oysters were collected for histological analysis, fixed in Davidson’s solution, embedded in paraffin, dehydrated in an ethanol series, sectioned (7μm thick and stained with Harris hematoxylin and Eosin (HE

  13. Large Neighborhood Search

    DEFF Research Database (Denmark)

    Pisinger, David; Røpke, Stefan

    2010-01-01

    Heuristics based on large neighborhood search have recently shown outstanding results in solving various transportation and scheduling problems. Large neighborhood search methods explore a complex neighborhood by use of heuristics. Using large neighborhoods makes it possible to find better...... candidate solutions in each iteration and hence traverse a more promising search path. Starting from the large neighborhood search method,we give an overview of very large scale neighborhood search methods and discuss recent variants and extensions like variable depth search and adaptive large neighborhood...

  14. Search for neutral leptons

    International Nuclear Information System (INIS)

    Perl, M.L.

    1984-12-01

    At present we know of three kinds of neutral leptons: the electron neutrino, the muon neutrino, and the tau neutrino. This paper reviews the search for additional neutral leptons. The method and significance of a search depends upon the model used for the neutral lepton being sought. Some models for the properties and decay modes of proposed neutral leptons are described. Past and present searches are reviewed. The limits obtained by some completed searches are given, and the methods of searches in progress are described. Future searches are discussed. 41 references

  15. Cube search, revisited

    Science.gov (United States)

    Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth

    2015-01-01

    Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with “equivalent” 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063

  16. Tolerance to air exposure of the New Zealand mudsnail Potamopyrgus antipodarum (Hydrobiidae, Mollusca as a prerequisite to survival in overland translocations

    Directory of Open Access Journals (Sweden)

    Alvaro Alonso

    2012-08-01

    Full Text Available Spreading throughout a new ecosystem is the last step of an exotic species to become invasive. In the case of invasive aquatic molluscs, tolerance to air exposure is one of the main mechanisms allowing overland translocation and spreading. The mudsnail Potamopyrgus antipodarum (Hydrobiidae, Mollusca is native to New Zealand but it has spread worldwide, invading ecosystems in Europe, Australia, America and Asia. The aim of our study is to assess mudsnail tolerance to air exposure, which may contribute to the successful overland translocation of this species. We conducted a laboratory experiment with four levels of air exposure (9, 18, 24 and 36 hours in a controlled climatic chamber. Snails were placed for 60 seconds in a laboratory paper filter to remove surface snail water. Then they were placed back in empty vessels during the four periods of air exposure, except the control group, which was immediately returned to water. At the end of each period of air exposure all vessels were filled with water and the cumulative mortality was monitored after 24, 96, 168 and 264 hours of rehydration. The calculated Lethal Times (i.e. the time of air exposure (in hours necessary to cause the death of 50% (LT50 or 99% (LT99 of the population and their 95% confidence limits at 24, 96, 168 and 264 hours were 28.1 (25.2–31.9, 26.9 (24.2–30.1, 25.9 (23.4–28.9 and 25.9 (23.4–28.9 hours, respectively for LT50, and 49.6 (42.7–63.3, 45.6 (39.9–56.5, 43.2 (38.0–53.0 and 43.2 (38.0–53.0 hours, respectively for LT99. Therefore an air exposure time over 43 hours caused the death of all studied individuals during all monitoring periods. Extending the monitoring period beyond 24 hours did not significantly change lethal times. Therefore, we recommend exposing fishing tools or boats at open air during at least 53 hours as a low cost measure to control mudsnail spread in early stages of invasion.

  17. Professional and Regulatory Search

    Science.gov (United States)

    Professional and Regulatory search are designed for people who use EPA web resources to do their job. You will be searching collections where information that is not relevant to Environmental and Regulatory professionals.

  18. Search on Rugged Landscapes

    DEFF Research Database (Denmark)

    Billinger, Stephan; Stieglitz, Nils; Schumacher, Terry

    2014-01-01

    This paper presents findings from a laboratory experiment on human decision-making in a complex combinatorial task. We find strong evidence for a behavioral model of adaptive search. Success narrows down search to the neighborhood of the status quo, while failure promotes gradually more explorative...... for local improvements too early. We derive stylized decision rules that generate the search behavior observed in the experiment and discuss the implications of our findings for individual decision-making and organizational search....

  19. Integrated vs. Federated Search

    DEFF Research Database (Denmark)

    Løvschall, Kasper

    2009-01-01

    Oplæg om forskelle og ligheder mellem integrated og federated search i bibliotekskontekst. Holdt ved temadag om "Integrated Search - samsøgning i alle kilder" på Danmarks Biblioteksskole den 22. januar 2009.......Oplæg om forskelle og ligheder mellem integrated og federated search i bibliotekskontekst. Holdt ved temadag om "Integrated Search - samsøgning i alle kilder" på Danmarks Biblioteksskole den 22. januar 2009....

  20. Mapping online consumer search

    NARCIS (Netherlands)

    Bronnenberg, B.J.; Kim, J.; Albuquerque, P.

    2011-01-01

    The authors propose a new method to visualize browsing behavior in so-called product search maps. Manufacturers can use these maps to understand how consumers search for competing products before choice, including how information acquisition and product search are organized along brands, product

  1. The Information Search

    Science.gov (United States)

    Doraiswamy, Uma

    2011-01-01

    This paper in the form of story discusses a college student's information search process. In this story we see Kuhlthau's information search process: initiation, selection, exploration, formulation, collection, and presentation. Katie is a student who goes in search of information for her class research paper. Katie's class readings, her interest…

  2. Keyword Search in Databases

    CERN Document Server

    Yu, Jeffrey Xu; Chang, Lijun

    2009-01-01

    It has become highly desirable to provide users with flexible ways to query/search information over databases as simple as keyword search like Google search. This book surveys the recent developments on keyword search over databases, and focuses on finding structural information among objects in a database using a set of keywords. Such structural information to be returned can be either trees or subgraphs representing how the objects, that contain the required keywords, are interconnected in a relational database or in an XML database. The structural keyword search is completely different from

  3. First record of a nematode Metastrongyloidea (Aelurostrongylus abstrusus larvae) in Achatina (Lissachatina) fulica (Mollusca, Achatinidae) in Brazil.

    Science.gov (United States)

    Thiengo, Silvana C; Fernandez, Monica A; Torres, Eduardo J L; Coelho, Pablo M; Lanfredi, Reinalda M

    2008-05-01

    Achatina (Lissachatina) fulica was introduced in Brazil in the 1980s for commercial purposes ("escargot" farming) and nowadays, mainly by human activity, it is widespread in at least 23 out of 26 Brazilian states and Brasília, including the Amazonian region and natural reserves, where besides a general nuisance for people it is a pest and also a public health concern, since it is one of the natural intermediate host of Angiostrongylus cantonensis, ethiological agent of the meningoencephalitis in Asia. As Brazil is experiencing the explosive phase of the invasion, the Laboratório de Malacologia do Instituto Oswaldo Cruz/Fiocruz has been receiving samples of these molluscs for identification and search for Angiostrongylus cantonensis and Angiostrongylus costaricensis larvae. While examining samples of A. fulica different nematode larvae were obtained, including Aelurostrongylus, whose different species are parasites of felids, dogs, primates, and badger. Morphological and morphometric analyses presented herein indicated the species Aelurostrongylus abstrusus, as well as the occurrence of other nematode larvae (Strongyluris-like) found in the interior of the pallial cavity of A. fulica. This is the first report in Brazil of the development of A. abstrusus infective larvae in A. fulica evidencing the veterinary importance of this mollusc in the transmission of A. abstrusus to domestic cats. Since the spread of A. fulica is pointed out in the literature as one of the main causative spread of the meningoencephalitis caused by A. cantonensis the authors emphasize the need of sanitary vigilance of snails and rats from vulnerable areas for A. cantonensis introduction as the port side areas.

  4. University Students' Online Information Searching Strategies in Different Search Contexts

    Science.gov (United States)

    Tsai, Meng-Jung; Liang, Jyh-Chong; Hou, Huei-Tse; Tsai, Chin-Chung

    2012-01-01

    This study investigates the role of search context played in university students' online information searching strategies. A total of 304 university students in Taiwan were surveyed with questionnaires in which two search contexts were defined as searching for learning, and searching for daily life information. Students' online search strategies…

  5. [Advanced online search techniques and dedicated search engines for physicians].

    Science.gov (United States)

    Nahum, Yoav

    2008-02-01

    In recent years search engines have become an essential tool in the work of physicians. This article will review advanced search techniques from the world of information specialists, as well as some advanced search engine operators that may help physicians improve their online search capabilities, and maximize the yield of their searches. This article also reviews popular dedicated scientific and biomedical literature search engines.

  6. Adaptive Large Neighbourhood Search

    DEFF Research Database (Denmark)

    Røpke, Stefan

    Large neighborhood search is a metaheuristic that has gained popularity in recent years. The heuristic repeatedly moves from solution to solution by first partially destroying the solution and then repairing it. The best solution observed during this search is presented as the final solution....... This tutorial introduces the large neighborhood search metaheuristic and the variant adaptive large neighborhood search that dynamically tunes parameters of the heuristic while it is running. Both heuristics belong to a broader class of heuristics that are searching a solution space using very large...... neighborhoods. The tutorial also present applications of the adaptive large neighborhood search, mostly related to vehicle routing problems for which the heuristic has been extremely successful. We discuss how the heuristic can be parallelized and thereby take advantage of modern desktop computers...

  7. Supporting Book Search

    DEFF Research Database (Denmark)

    Bogers, Toine; Petras, Vivien

    2017-01-01

    of information needs. In this paper, we present a large-scale empirical comparison of the effectiveness of book metadata elements for searching complex information needs. Using a test collection of over 2 million book records and over 330 real-world book search requests, we perform a highly controlled and in......-depth analysis of topical metadata, comparing controlled vocabularies with social tags. Tags perform better overall in this setting, but controlled vocabulary terms provide complementary information, which will improve a search. We analyze potential underlying factors that contribute to search performance......, such as the relevance aspect(s) mentioned in a request or the type of book. In addition, we investigate the possible causes of search failure. We conclude that neither tags nor controlled vocabularies are wholly suited to handling the complex information needs in book search, which means that different approaches...

  8. ElasticSearch cookbook

    CERN Document Server

    Paro, Alberto

    2013-01-01

    Written in an engaging, easy-to-follow style, the recipes will help you to extend the capabilities of ElasticSearch to manage your data effectively.If you are a developer who implements ElasticSearch in your web applications, manage data, or have decided to start using ElasticSearch, this book is ideal for you. This book assumes that you've got working knowledge of JSON and Java

  9. Mastering ElasticSearch

    CERN Document Server

    Kuc, Rafal

    2013-01-01

    A practical tutorial that covers the difficult design, implementation, and management of search solutions.Mastering ElasticSearch is aimed at to intermediate users who want to extend their knowledge about ElasticSearch. The topics that are described in the book are detailed, but we assume that you already know the basics, like the query DSL or data indexing. Advanced users will also find this book useful, as the examples are getting deep into the internals where it is needed.

  10. Search engine optimization

    OpenAIRE

    Marolt, Klemen

    2013-01-01

    Search engine optimization techniques, often shortened to “SEO,” should lead to first positions in organic search results. Some optimization techniques do not change over time, yet still form the basis for SEO. However, as the Internet and web design evolves dynamically, new optimization techniques flourish and flop. Thus, we looked at the most important factors that can help to improve positioning in search results. It is important to emphasize that none of the techniques can guarantee high ...

  11. Mobile Search and Advertising

    OpenAIRE

    Lovitskii, Vladimir; McCaffery, Colin; Thrasher, Michael; Traynor, David; Wright, Peter

    2009-01-01

    Mobile advertising is a rapidly growing sector providing brands and marketing agencies the opportunity to connect with consumers beyond traditional and digital media and instead communicate directly on their mobile phones. Mobile advertising will be intrinsically linked with mobile search, which has transported from the internet to the mobile and is identified as an area of potential growth. The result of mobile searching show that as a general rule such search result exceed 1...

  12. Search and Disrupt

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders

    . However, incumbent sources engaged in capability reconfiguration to accommodate disruption improve search efforts in disruptive technologies. The paper concludes that the value of external sources is contingent on more than their knowledge. Specifically, interdependence of sources in search gives rise...... to influence from individual strategic interests on the outcomes. More generally, this points to the need for understanding the two-way influence of sources, rather than viewing external search as one-way knowledge accessing....

  13. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  14. Google Power Search

    CERN Document Server

    Spencer, Stephan

    2011-01-01

    Behind Google's deceptively simple interface is immense power for both market and competitive research-if you know how to use it well. Sure, basic searches are easy, but complex searches require specialized skills. This concise book takes you through the full range of Google's powerful search-refinement features, so you can quickly find the specific information you need. Learn techniques ranging from simple Boolean logic to URL parameters and other advanced tools, and see how they're applied to real-world market research examples. Incorporate advanced search operators such as filetype:, intit

  15. Optimization of partial search

    International Nuclear Information System (INIS)

    Korepin, Vladimir E

    2005-01-01

    A quantum Grover search algorithm can find a target item in a database faster than any classical algorithm. One can trade accuracy for speed and find a part of the database (a block) containing the target item even faster; this is partial search. A partial search algorithm was recently suggested by Grover and Radhakrishnan. Here we optimize it. Efficiency of the search algorithm is measured by the number of queries to the oracle. The author suggests a new version of the Grover-Radhakrishnan algorithm which uses a minimal number of such queries. The algorithm can run on the same hardware that is used for the usual Grover algorithm. (letter to the editor)

  16. Citation Searching: Search Smarter & Find More

    Science.gov (United States)

    Hammond, Chelsea C.; Brown, Stephanie Willen

    2008-01-01

    The staff at University of Connecticut are participating in Elsevier's Student Ambassador Program (SAmP) in which graduate students train their peers on "citation searching" research using Scopus and Web of Science, two tremendous citation databases. They are in the fourth semester of these training programs, and they are wildly successful: They…

  17. Constructing Effective Search Strategies for Electronic Searching.

    Science.gov (United States)

    Flanagan, Lynn; Parente, Sharon Campbell

    Electronic databases have grown tremendously in both number and popularity since their development during the 1960s. Access to electronic databases in academic libraries was originally offered primarily through mediated search services by trained librarians; however, the advent of CD-ROM and end-user interfaces for online databases has shifted the…

  18. INTERFACING GOOGLE SEARCH ENGINE TO CAPTURE USER WEB SEARCH BEHAVIOR

    OpenAIRE

    Fadhilah Mat Yamin; T. Ramayah

    2013-01-01

    The behaviour of the searcher when using the search engine especially during the query formulation is crucial. Search engines capture users’ activities in the search log, which is stored at the search engine server. Due to the difficulty of obtaining this search log, this paper proposed and develops an interface framework to interface a Google search engine. This interface will capture users’ queries before redirect them to Google. The analysis of the search log will show that users are utili...

  19. Vertical Search Engines

    OpenAIRE

    Curran, Kevin; Mc Glinchey, Jude

    2017-01-01

    This paper outlines the growth in popularity of vertical search engines, their origins, the differences between them and well-known broad based search engines such as Google and Yahoo. We also discuss their use in business-to-business, their marketing and advertising costs, what the revenue streams are and who uses them.

  20. African Environment: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  1. Mathematics Connection: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    , is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...

  3. Innovation: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  4. Human memory search

    NARCIS (Netherlands)

    Davelaar, E.J.; Raaijmakers, J.G.W.; Hills, T.T.; Robbins, T.W.; Todd, P.M.

    2012-01-01

    The importance of understanding human memory search is hard to exaggerate: we build and live our lives based on what whe remember. This chapter explores the characteristics of memory search, with special emphasis on the use of retrieval cues. We introduce the dependent measures that are obtained

  5. Zede Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  6. Searches for Supersymmetry

    CERN Document Server

    Ventura, Andrea; The ATLAS collaboration

    2017-01-01

    New and recent results on Supersymmetry searches are shown for the ATLAS and the CMS experiments. Analyses with about 36 fb$^{-1}$ are considered for searches concerning light squarks and gluinos, direct pair production of 3$^{rd}$ generation squarks, electroweak production of charginos, neutralinos, sleptons, R-parity violating scenarios and long-lived particles.

  7. Searches for Supersymmetry

    CERN Document Server

    Ventura, Andrea; The ATLAS collaboration

    2017-01-01

    New and recents results on Supersymmetry searches are shown for the ATLAS and the CMS experiments. Analyses with about 36 fb^-1 are considered for searches concerning light squarks and gluinos, direct pair production of 3rd generation squarks, electroweak production of charginos, neutralinos, sleptons, R-parity violating scenarios and long-lived particles.

  8. Philosophical Papers: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  9. Kiswahili: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. Sciences & Nature: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  11. Vulture News: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  12. Agronomie Africaine: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  13. Distributed Deep Web Search

    NARCIS (Netherlands)

    Tjin-Kam-Jet, Kien

    2013-01-01

    The World Wide Web contains billions of documents (and counting); hence, it is likely that some document will contain the answer or content you are searching for. While major search engines like Bing and Google often manage to return relevant results to your query, there are plenty of situations in

  14. ElasticSearch cookbook

    CERN Document Server

    Paro, Alberto

    2015-01-01

    If you are a developer who implements ElasticSearch in your web applications and want to sharpen your understanding of the core elements and applications, this is the book for you. It is assumed that you've got working knowledge of JSON and, if you want to extend ElasticSearch, of Java and related technologies.

  15. Africa Insight: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  16. Critical Arts: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. Ergonomics SA: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  18. Kenya Veterinarian: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  19. Counsellor (The): Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  20. Search for a planet

    International Nuclear Information System (INIS)

    Tokovinin, A.A.

    1986-01-01

    The problem of search for star planets is discussed in a popular form. Two methods of search for planets are considered: astrometric and spectral. Both methods complement one another. An assumption is made that potential possessors of planets are in the first place yellow and red dwarfs with slow axial rotation. These stars are the most numerous representatives of Galaxy population

  1. Nigerian Libraries: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Search of associative memory.

    NARCIS (Netherlands)

    Raaijmakers, J.G.W.; Shiffrin, R.M.

    1981-01-01

    Describes search of associative memory (SAM), a general theory of retrieval from long-term memory that combines features of associative network models and random search models. It posits cue-dependent probabilistic sampling and recovery from an associative network, but the network is specified as a

  3. African Zoology: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  4. Fractional charge search

    International Nuclear Information System (INIS)

    Innes, W.; Klein, S.; Perl, M.; Price, J.C.

    1982-06-01

    A device to search for fractional charge in matter is described. The sample is coupled to a low-noise amplifier by a periodically varying capacitor and the resulting signal is synchronously detected. The varying capacitor is constructed as a rapidly spinning wheel. Samples of any material in volumes of up to 0.05 ml may be searched in less than an hour

  5. Intermittent search strategies

    Science.gov (United States)

    Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

    2011-01-01

    This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

  6. Tales from the Field: Search Strategies Applied in Web Searching

    Directory of Open Access Journals (Sweden)

    Soohyung Joo

    2010-08-01

    Full Text Available In their web search processes users apply multiple types of search strategies, which consist of different search tactics. This paper identifies eight types of information search strategies with associated cases based on sequences of search tactics during the information search process. Thirty-one participants representing the general public were recruited for this study. Search logs and verbal protocols offered rich data for the identification of different types of search strategies. Based on the findings, the authors further discuss how to enhance web-based information retrieval (IR systems to support each type of search strategy.

  7. How Users Search the Library from a Single Search Box

    Science.gov (United States)

    Lown, Cory; Sierra, Tito; Boyer, Josh

    2013-01-01

    Academic libraries are turning increasingly to unified search solutions to simplify search and discovery of library resources. Unfortunately, very little research has been published on library user search behavior in single search box environments. This study examines how users search a large public university library using a prominent, single…

  8. Composite Differential Search Algorithm

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2014-01-01

    Full Text Available Differential search algorithm (DS is a relatively new evolutionary algorithm inspired by the Brownian-like random-walk movement which is used by an organism to migrate. It has been verified to be more effective than ABC, JDE, JADE, SADE, EPSDE, GSA, PSO2011, and CMA-ES. In this paper, we propose four improved solution search algorithms, namely “DS/rand/1,” “DS/rand/2,” “DS/current to rand/1,” and “DS/current to rand/2” to search the new space and enhance the convergence rate for the global optimization problem. In order to verify the performance of different solution search methods, 23 benchmark functions are employed. Experimental results indicate that the proposed algorithm performs better than, or at least comparable to, the original algorithm when considering the quality of the solution obtained. However, these schemes cannot still achieve the best solution for all functions. In order to further enhance the convergence rate and the diversity of the algorithm, a composite differential search algorithm (CDS is proposed in this paper. This new algorithm combines three new proposed search schemes including “DS/rand/1,” “DS/rand/2,” and “DS/current to rand/1” with three control parameters using a random method to generate the offspring. Experiment results show that CDS has a faster convergence rate and better search ability based on the 23 benchmark functions.

  9. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  10. Extirpation of freshwater mussels (Bivalvia: Unionidae) following the invasion of dreissenid mussels in an interconnecting river of the Laurentian Great Lakes

    Science.gov (United States)

    Schloesser, Don W.; Metcalfe-Smith, Janice L.; Kovalak, William P.; Longton, Gary D.; Smithee, Rick D.

    2006-01-01

    Previous (1992-1994) surveys for native freshwater mussels (Unionidae) along main channels of the Detroit River showed that unionids had been extirpated from all but four sites in the upper reaches of the river due to impacts of dreissenid mussels (Dreissena polymorpha and D. bugensis). These four sites were surveyed again in 1998 using the same sampling method (timed-random searches) to determine if they may serve as ''refugia'' where unionids and dreissenids co-exist. Two additional sites were sampled using additional methods (excavated-quadrat and line-transect searches) for comparison with unpublished data collected in 1987 and 1990. A total of four individuals of four species (Actinonaias ligamentina, Cyclonaias tuberculata, Lasmigona complanata and Pleurobema sintoxia) were found by timed-random searches at four sites in 1998 compared to 720 individuals of 24 species in 1992 and 39 individuals of 13 species in 1994. Excavated-quadrat and line-transect searches at the two additional sites yielded only one live specimen of Ptychobranchus fasciolaris compared to 288 individuals of 18 species in 1987 and 1990. Results of this study suggest that remaining densities of unionids in channels of the Detroit River are too low to support viable reproducing populations of any species. Therefore, we conclude that unionids have been extirpated from main channels of the Detroit River due to dreissenid infestation. As the Detroit River was one of the first water bodies in North America to be invaded by dreissenids, it is likely that unionids will also be extirpated from many other rivers and lakes across eastern North America over the next few decades. Resource agencies should be encouraged to implement active management programs to protect remaining unionid populations from zebra mussels.

  11. Magnetic monopole search experiments

    International Nuclear Information System (INIS)

    Stone, J.L.

    1986-01-01

    Experimental searches for the elusive magnetic monopole have extended over 50 years -- ever since Dirac showed that the existence of isolated magnetic charges could account for the observation of quantized electric charge. Early searches for Dirac's monopole were hampered since there was no indication of the expected monopole mass, velocity, or origin in the theory. Consequently, numerous experiments searched more or less blindly for relativistic low mass monopoles in the cosmic rays and in particle collisions at high energy accelerators. In this paper, the author reviews briefly the monopole properties which are relevant for their detection and summarize current experimental efforts using induction, ionization/excitation, and catalysis techniques

  12. Exotic searches at lep

    International Nuclear Information System (INIS)

    Seager, P.

    2001-01-01

    The search for exotic processes at LEP is presented. The Standard Model Higgs has as yet not been observed. This provides freedom to search for processes beyond the Standard Model and even beyond the minimal version of the supersymmetric extension to the Standard Model. This paper outlines the searches for charged Higgs bosons, fermiophobic Higgs bosons, invisibly decaying Higgs bosons, technicolor, leptoquarks, unstable heavy leptons and excited leptons. The results presented are those from the LEP collaborations using data taken up to a centre-of-mass energy of √s = 202 GeV. (author)

  13. Searching low and high

    DEFF Research Database (Denmark)

    Laursen, Keld; Salter, Ammon

    2003-01-01

    AbstractThis paper examines the factors that influence whether firms draw from universities in theirinnovative activities. The link between the universities and industrial innovation, and the role ofdifferent search strategies in influencing the propensity of firms to use universities is explored.......The results suggest that firms who adopt `open' search strategies and invest in R&D are morelikely than other firms to draw from universities, indicating that managerial choice matters inshaping the propensity of firms to draw from universities.Key words: University-industry links, innovation, external search...

  14. Modified harmony search

    Science.gov (United States)

    Mohamed, Najihah; Lutfi Amri Ramli, Ahmad; Majid, Ahmad Abd; Piah, Abd Rahni Mt

    2017-09-01

    A metaheuristic algorithm, called Harmony Search is quite highly applied in optimizing parameters in many areas. HS is a derivative-free real parameter optimization algorithm, and draws an inspiration from the musical improvisation process of searching for a perfect state of harmony. Propose in this paper Modified Harmony Search for solving optimization problems, which employs a concept from genetic algorithm method and particle swarm optimization for generating new solution vectors that enhances the performance of HS algorithm. The performances of MHS and HS are investigated on ten benchmark optimization problems in order to make a comparison to reflect the efficiency of the MHS in terms of final accuracy, convergence speed and robustness.

  15. ElasticSearch server

    CERN Document Server

    Rogozinski, Marek

    2014-01-01

    This book is a detailed, practical, hands-on guide packed with real-life scenarios and examples which will show you how to implement an ElasticSearch search engine on your own websites.If you are a web developer or a user who wants to learn more about ElasticSearch, then this is the book for you. You do not need to know anything about ElastiSeach, Java, or Apache Lucene in order to use this book, though basic knowledge about databases and queries is required.

  16. Marine mollusca of oxygen isotope stages of the last 2 million years in New Zealand. Part 1, Revised generic positions and recognition of warm-water and cool-water migrants

    International Nuclear Information System (INIS)

    Beu, A.G.

    2004-01-01

    Warm-water molluscs were transported to Wanganui Basin from the northeastern North Island during Pleistocene time as planktotrophic larvae. This is not possible at present, so their occurrence in Wanganui Basin correlates with breaches of the Auckland isthmus during high sea levels. The end of Nukumaruan time is clearly defined by the extinction of 29 genera of molluscs (most only locally) during this stage, including 15 at the end. The extinction likely was caused by the initial closure of the Auckland isthmus. Migrants to Wanganui from the northeastern North Island indicate that breaches of the isthmus during interglacials commenced in oxygen isotope stage (OIS) 25, just before the mid-Pleistocene transition (MPT). Appearances of taxa from Australia at Wanganui during OIS 17-9 therefore indicate that warm-water taxa were transported to New Zealand during interglacial maxima after the MPT. The migrants provide the first molluscan biostratigraphy at the OIS scale. The Castlecliffian/Nukumaruan boundary, at the base of Ototoka tephra at Ototoka Beach, Wanganui, falls within OIS 57, with an age of c. 1.63 Ma. It is also dated at 1.63 Ma by the position with respect to the geomagnetic polarity time-scale of three chemically indistinguishable tephra in ODP core 1123. This paper presents the first results of a reassessment of the taxonomy and time ranges of the fossil marine molluscan fauna that occupied New Zealand during the last 2 m.y. (latest Pliocene-Holocene). Time ranges are compiled in oxygen isotope stages rather than in the traditional 'local' (or regional) stages in use in New Zealand. This should provide precision in time ranges of the order of 40,000-100,000 yr, rather than the 0.34-1.3 m.y. duration of New Zealand local stages of the latest Neogene (Nukumaruan, Castlecliffian, and Haweran Stages). The reassessment is aimed also, though, at providing evidence from Mollusca of climate change over this period. Much useful information on paleoclimates can be

  17. Beyond MEDLINE for literature searches.

    Science.gov (United States)

    Conn, Vicki S; Isaramalai, Sang-arun; Rath, Sabyasachi; Jantarakupt, Peeranuch; Wadhawan, Rohini; Dash, Yashodhara

    2003-01-01

    To describe strategies for a comprehensive literature search. MEDLINE searches result in limited numbers of studies that are often biased toward statistically significant findings. Diversified search strategies are needed. Empirical evidence about the recall and precision of diverse search strategies is presented. Challenges and strengths of each search strategy are identified. Search strategies vary in recall and precision. Often sensitivity and specificity are inversely related. Valuable search strategies include examination of multiple diverse computerized databases, ancestry searches, citation index searches, examination of research registries, journal hand searching, contact with the "invisible college," examination of abstracts, Internet searches, and contact with sources of synthesized information. Extending searches beyond MEDLINE enables researchers to conduct more systematic comprehensive searches.

  18. Custom Search Engines: Tools & Tips

    Science.gov (United States)

    Notess, Greg R.

    2008-01-01

    Few have the resources to build a Google or Yahoo! from scratch. Yet anyone can build a search engine based on a subset of the large search engines' databases. Use Google Custom Search Engine or Yahoo! Search Builder or any of the other similar programs to create a vertical search engine targeting sites of interest to users. The basic steps to…

  19. Searching with Quantum Computers

    OpenAIRE

    Grover, Lov K.

    2000-01-01

    This article introduces quantum computation by analogy with probabilistic computation. A basic description of the quantum search algorithm is given by representing the algorithm as a C program in a novel way.

  20. Dark matter search

    International Nuclear Information System (INIS)

    Bernabei, R.

    2003-01-01

    Some general arguments on the particle Dark Matter search are addressed. The WIMP direct detection technique is mainly considered and recent results obtained by exploiting the annual modulation signature are summarized. (author)

  1. Searches at LEP

    CERN Document Server

    Junk, Tom

    2000-01-01

    Searches have been conducted for a broad range of new phenomena by the four experiments ALEPH, DELPHI, L3, and OPAL, at LEP2. Each experiment contributes approximately 150 pb-1 of e+e- annihilation data with a mean sqrt(s) of 205.9 GeV in 2000 to these searches (data prepared for the September 5 LEPC meeting). The statistical procedure for setting limits and evaluating the significance of excesses observed in the data is reviewed. Search results are presented for the Standard Model Higgs boson, the neutral Higgs bosons in the MSSM, charged Higgs bosons, invisibly decaying Higgs bosons produced by Higgs-strahlung, and fermiophobic Higgs bosons. Search results are briefly summarized for gauginos, stops, and staus. The photon recoil spectrum is checked for hints of new physics.

  2. Automated search for supernovae

    International Nuclear Information System (INIS)

    Kare, J.T.

    1984-01-01

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion

  3. Automated search for supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  4. Fuzzing and Vulnerabilities Search

    OpenAIRE

    Stanislav Evgenyevich Kirillov; Nikolai Petrovich Lavrentiev

    2013-01-01

    Fuzzing for vulnerabilities can be very effective if we know the input data format. This work contains description of network message format recovery algorithm and the usage of restored data model in fuzzing and vulnerabilities search.

  5. Fuzzing and Vulnerabilities Search

    Directory of Open Access Journals (Sweden)

    Stanislav Evgenyevich Kirillov

    2013-02-01

    Full Text Available Fuzzing for vulnerabilities can be very effective if we know the input data format. This work contains description of network message format recovery algorithm and the usage of restored data model in fuzzing and vulnerabilities search.

  6. Chemical Search Web Utility

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Chemical Search Web Utility is an intuitive web application that allows the public to easily find the chemical that they are interested in using, and which...

  7. Dark matter search

    Energy Technology Data Exchange (ETDEWEB)

    Bernabei, R [Dipto. di Fisica, Universita di Roma ' Tor Vergata' and INFN, sez. Roma2, Rome (Italy)

    2003-08-15

    Some general arguments on the particle Dark Matter search are addressed. The WIMP direct detection technique is mainly considered and recent results obtained by exploiting the annual modulation signature are summarized. (author)

  8. Searches for new physics

    International Nuclear Information System (INIS)

    Ellis, J.; Pauss, F.

    1989-01-01

    The CERN p bar p Collider has been the first accelerator to operate in a completely new energy domain, reaching center-of-mass energies an order of magnitude larger than those previously available with the intersecting Storage Rings (ISR) at CERN, or with the Positron-Electron Tandem Ring Accelerator (PETRA) at DESY and the Positron-Electron Project (PEP) at SLAC. Naturally there has been great interest in the searches for new physics in this virgin territory. Theorists have approached these searches from either or both of two rival points of view. Either they have had an a priori prejudice as to what new physics should be searched for, and what its signatures should be, or they have tried to interpret a posteriori some experimental observations. The basic building-blocks of new physics in the 100 GeV energy domain are jets j, charged leptons l, photons γ, and missing transverse energy E T . Therefore searches have been conducted in channels which are combinations of these elements. It also shows some of the main a priori theoretical prejudices which can be explored in each of these channels. The layout of the rest of this paper is as follows. There are sections discussing each of the major prejudices: the Standard Model supersymmetry; extra gauge degrees of freedom; composite models; and other possibilities. Each of these sections contains a description of the motivations and characteristics of the new physics to be searched for, followed by a review of the searches made up to now at the CERN p bar p Collider. Finally, it summarizes the lessons to be learnt so far from searches for new physics at the CERN p bar p Collider, and previews some of the prospects for the next rounds of collider searches at CERN and FNAL

  9. Spatial Search, Position Papers

    OpenAIRE

    Center for Spatial Studies, UCSB

    2014-01-01

    The Spatial Search specialist meeting in Santa Barbara (December 2014) brought together 35 academic and industry representatives from computational, geospatial, and cognitive sciences with interest in focused discussions on the development of an interdisciplinary research agenda to advance spatial search from scientific and engineering viewpoints. The position papers from participants represent the shared expertise that guided discussions and the formulation of research questions about proces...

  10. Search and imperative programming

    OpenAIRE

    Apt, Krzysztof; Schaerf, A.

    1996-01-01

    textabstractWe augment the expressive power of imperative programming in order to make it a more attractive vehicle for problems that involve search.The proposed additions are limited yet powerful and are inspired by the logic programming paradigm.We illustrate their use by presenting solutions to a number of classical problems, including the straight search problem, the knapsack problem, and the 8 queens problem. These solutions are substantially simpler than their counterparts written in th...

  11. Status of gluonium searches

    International Nuclear Information System (INIS)

    Heusch, C.A.; California Univ., Santa Cruz, CA

    1991-01-01

    Quantum chromodynamics predicts the existence of quarkless mesons. The search for these hadrons has been ingenious and persevering. A review is presented of the current status of research that considers all model-dependent theoretical prejudice when searching for specific states. Early hints for candidate states have been investigated in the light of recent data, mostly from the Mark III Collaboration, in radiative charmonium decay. No 'smoking-gun' candidate stands out. (R.P.) 25 refs., 20 figs., 2 tabs

  12. Monopole searches at ISABELLE

    International Nuclear Information System (INIS)

    Giacomelli, G.; Thorndike, A.

    1975-01-01

    A discussion is given which supports the continuance of the search for magnetic monopoles at ISABELLE, based on the following assumptions: (1) by 1982 monopoles have not been found; (2) this indicates that, if they exist, they are very massive; (3) other monopole properties are as they are usually assumed to be. An experiment to search for dense tracks is described, an outline is given of a monopole collector for induced current detection, and some discussion is given of the multigamma approach

  13. Global OpenSearch

    Science.gov (United States)

    Newman, D. J.; Mitchell, A. E.

    2015-12-01

    At AGU 2014, NASA EOSDIS demonstrated a case-study of an OpenSearch framework for Earth science data discovery. That framework leverages the IDN and CWIC OpenSearch API implementations to provide seamless discovery of data through the 'two-step' discovery process as outlined by the Federation for Earth Sciences (ESIP) OpenSearch Best Practices. But how would an Earth Scientist leverage this framework and what are the benefits? Using a client that understands the OpenSearch specification and, for further clarity, the various best practices and extensions, a scientist can discovery a plethora of data not normally accessible either by traditional methods (NASA Earth Data Search, Reverb, etc) or direct methods (going to the source of the data) We will demonstrate, via the CWICSmart web client, how an earth scientist can access regional data on a regional phenomena in a uniform and aggregated manner. We will demonstrate how an earth scientist can 'globalize' their discovery. You want to find local data on 'sea surface temperature of the Indian Ocean'? We can help you with that. 'European meteorological data'? Yes. 'Brazilian rainforest satellite imagery'? That too. CWIC allows you to get earth science data in a uniform fashion from a large number of disparate, world-wide agencies. This is what we mean by Global OpenSearch.

  14. Search Tips: MedlinePlus

    Science.gov (United States)

    ... of this page: https://medlineplus.gov/searchtips.html Search Tips To use the sharing features on this page, please enable JavaScript. How do I search MedlinePlus? The search box appears at the top ...

  15. Axion Searches, Old and New

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    Outline of the lecture: Constraints from laboratory searches and astrophysics, axion cosmology, the cavity detector of dark matter axions, solar axion searches, laser experiments, a telescope search, macroscopic forces mediated by axions.

  16. SEARCHES FOR SUPERSYMMETRY IN ATLAS

    CERN Document Server

    Xu, Da; The ATLAS collaboration

    2017-01-01

    A wide range of supersymmetric searches are presented. All searches are based on the proton- proton collision dataset collected by the ATLAS experiment during the 2015 and 2016 (before summer) run with a center-of-mass energy of 13 TeV, corresponding to an integrated lumi- nosity of 36.1 (36.7) fb-1. The searches are categorized into inclusive gluino and squark search, third generation search, electroweak search, prompt RPV search and long-lived par- ticle search. No evidence of new physics is observed. The results are intepreted in various models and expressed in terms of limits on the masses of new particles.

  17. Market Dominance and Search Quality in the Search Engine Market

    NARCIS (Netherlands)

    Lianos, I.; Motchenkova, E.I.

    2013-01-01

    We analyze a search engine market from a law and economics perspective and incorporate the choice of quality-improving innovations by a search engine platform in a two-sided model of Internet search engine. In the proposed framework, we first discuss the legal issues the search engine market raises

  18. SearchResultFinder: federated search made easy

    NARCIS (Netherlands)

    Trieschnigg, Rudolf Berend; Tjin-Kam-Jet, Kien; Hiemstra, Djoerd

    Building a federated search engine based on a large number existing web search engines is a challenge: implementing the programming interface (API) for each search engine is an exacting and time-consuming job. In this demonstration we present SearchResultFinder, a browser plugin which speeds up

  19. Children's Search Engines from an Information Search Process Perspective.

    Science.gov (United States)

    Broch, Elana

    2000-01-01

    Describes cognitive and affective characteristics of children and teenagers that may affect their Web searching behavior. Reviews literature on children's searching in online public access catalogs (OPACs) and using digital libraries. Profiles two Web search engines. Discusses some of the difficulties children have searching the Web, in the…

  20. Mastering Search Analytics Measuring SEO, SEM and Site Search

    CERN Document Server

    Chaters, Brent

    2011-01-01

    Many companies still approach Search Engine Optimization (SEO) and paid search as separate initiatives. This in-depth guide shows you how to use these programs as part of a comprehensive strategy-not just to improve your site's search rankings, but to attract the right people and increase your conversion rate. Learn how to measure, test, analyze, and interpret all of your search data with a wide array of analytic tools. Gain the knowledge you need to determine the strategy's return on investment. Ideal for search specialists, webmasters, and search marketing managers, Mastering Search Analyt

  1. Search for glueballs

    Energy Technology Data Exchange (ETDEWEB)

    Toki, W. [Colorado State Univ., Ft. Collins, CO (United States). Dept. of Physics

    1997-06-01

    In these Summer School lectures, the author reviews the results of recent glueball searches. He begins with a brief review of glueball phenomenology and meson spectroscopy, including a discussion of resonance behavior. The results on the f{sub o}(1500) and f{sub J}(1700) resonances from proton-antiproton experiments and radiative J/{Psi} decays are discussed. Finally, {pi}{pi} and {eta}{pi} studies from D{sub s} decays and exotic meson searches are reviewed. 46 refs., 40 figs.

  2. Upgrading Enterprise Search

    Energy Technology Data Exchange (ETDEWEB)

    McDunn, R

    2005-04-28

    This presentation will describe the process we went through this past year to upgrade our enterprise search tool from a very old version of Inktomi to the latest version of Verity Ultraseek. We started with requirements gathering and then compared requirements against several available products to determine which product to choose. After purchasing the product, we worked through several defined phases of implementation and customization, with initial rollout late January 2004. Finally, we will show you where we are today and describe future search plans.

  3. SUSY Searches at ATLAS

    CERN Document Server

    Mamuzic, Judita; The ATLAS collaboration

    2017-01-01

    Supersymmetry (SUSY) is considered one of the best motivated extensions of the Standard Model. It postulates a fundamental symmetry between fermions and bosons, and introduces a set of new supersymmetric particles at the electroweak scale. It addresses the hierarchy and naturalness problem, gives a solution to the gauge coupling unification, and offers a cold dark matter candidate. Different aspects of SUSY searches, using strong, electroweak, third generation production, and R-parity violation and long lived particles are being studied at the LHC. An overview of most recent SUSY searches results using the 13 TeV ATLAS RUN2 data will be presented.

  4. Quark search conference

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    In spite of (or perhaps because of) the present doctrine of total quark confinement held by the majority of particle theorists, experimental searches for free fractional charge and other anomalous stable particles in ordinary matter have been increasing in number during recent years, using a range of techniques of increasing sophistication and sensitivity. As a result, researchers in this area had a conference to themselves in June. About 40 participants and 150 observers gathered at San Francisco State University to report progress and discuss future plans, with representatives present from almost every group involved in quark searches

  5. Searching for supersymmetry scalelessly

    Energy Technology Data Exchange (ETDEWEB)

    Schlaffer, M. [DESY, Hamburg (Germany); Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Spannowsky, M. [Durham University, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Weiler, A. [Technische Universitaet Muenchen, Physik Department T75, Garching (Germany)

    2016-08-15

    In this paper we propose a scale invariant search strategy for hadronic top or bottom plus missing energy final states. We present a method which shows flat efficiencies and background rejection factors over broad ranges of parameters and masses. The resulting search can easily be recast into a limit on alternative models. We show the strength of the method in a natural SUSY setup where stop and sbottom squarks are pair produced and decay into hadronically decaying top quarks or bottom quarks and higgsinos. (orig.)

  6. Search Parameter Optimization for Discrete, Bayesian, and Continuous Search Algorithms

    Science.gov (United States)

    2017-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS SEARCH PARAMETER OPTIMIZATION FOR DISCRETE , BAYESIAN, AND CONTINUOUS SEARCH ALGORITHMS by...to 09-22-2017 4. TITLE AND SUBTITLE SEARCH PARAMETER OPTIMIZATION FOR DISCRETE , BAYESIAN, AND CON- TINUOUS SEARCH ALGORITHMS 5. FUNDING NUMBERS 6...simple search and rescue acts to prosecuting aerial/surface/submersible targets on mission. This research looks at varying the known discrete and

  7. The Evolution of Web Searching.

    Science.gov (United States)

    Green, David

    2000-01-01

    Explores the interrelation between Web publishing and information retrieval technologies and lists new approaches to Web indexing and searching. Highlights include Web directories; search engines; portalisation; Internet service providers; browser providers; meta search engines; popularity based analysis; natural language searching; links-based…

  8. Prices and heterogeneous search costs

    NARCIS (Netherlands)

    Luis Moraga-Gonzalez, Jose; Sandor, Zsolt; Wildenbeest, Matthijs R.

    2017-01-01

    We study price formation in a model of consumer search for differentiated products in which consumers have heterogeneous search costs. We provide conditions under which a pure-strategy symmetric Nash equilibrium exists and is unique. Search costs affect two margins-the intensive search margin (or

  9. Complete local search with memory

    NARCIS (Netherlands)

    Ghosh, D.; Sierksma, G.

    2000-01-01

    Neighborhood search heuristics like local search and its variants are some of the most popular approaches to solve discrete optimization problems of moderate to large size. Apart from tabu search, most of these heuristics are memoryless. In this paper we introduce a new neighborhood search heuristic

  10. Online Patent Searching: The Realities.

    Science.gov (United States)

    Kaback, Stuart M.

    1983-01-01

    Considers patent subject searching capabilities of major online databases, noting patent claims, "deep-indexed" files, test searches, retrieval of related references, multi-database searching, improvements needed in indexing of chemical structures, full text searching, improvements needed in handling numerical data, and augmenting a…

  11. Self-learning search engines

    NARCIS (Netherlands)

    Schuth, A.

    2015-01-01

    How does a search engine such as Google know which search results to display? There are many competing algorithms that generate search results, but which one works best? We developed a new probabilistic method for quickly comparing large numbers of search algorithms by examining the results users

  12. Standardization of Keyword Search Mode

    Science.gov (United States)

    Su, Di

    2010-01-01

    In spite of its popularity, keyword search mode has not been standardized. Though information professionals are quick to adapt to various presentations of keyword search mode, novice end-users may find keyword search confusing. This article compares keyword search mode in some major reference databases and calls for standardization. (Contains 3…

  13. Biased Predecessor Search

    DEFF Research Database (Denmark)

    Bose, Prosenjit; Fagerberg, Rolf; Howat, John

    2016-01-01

    We consider the problem of performing predecessor searches in a bounded universe while achieving query times that depend on the distribution of queries. We obtain several data structures with various properties: in particular, we give data structures that achieve expected query times logarithmic...

  14. Biased predecessor search

    DEFF Research Database (Denmark)

    Bose, Prosenjit; Fagerberg, Rolf; Howat, John

    2014-01-01

    We consider the problem of performing predecessor searches in a bounded universe while achieving query times that depend on the distribution of queries. We obtain several data structures with various properties: in particular, we give data structures that achieve expected query times logarithmic...

  15. Quantum Search and Beyond

    Science.gov (United States)

    2008-07-02

    mechanics leads to non-local paradoxical effects (physicists sometimes call this "spooky action at a distance"). Spatial searching is the problem where...resource of EPR pairs, and that they use the states |0L〉 = |00〉+ |11〉 (|1L〉 = |00〉 − |11〉) to encode a logical zero (one). Note that each of them can set

  16. In Search of Insight.

    Science.gov (United States)

    Kaplan, Craig A.; Simon, Herbert A.

    1990-01-01

    Attaining the insight needed to solve the Mutilated Checkerboard problem, which requires discovery of an effective problem representation (EPR), is described. Performance on insight problems can be predicted from the availability of generators and constraints in the search for an EPR. Data for 23 undergraduates were analyzed. (TJH)

  17. ChemSearch Journal

    African Journals Online (AJOL)

    Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. Journal Homepage Image. Chemsearch Journal is a peer – reviewed journal that publishes original research work, scientific papers and technical reports in all the field of Chemistry (pure science, agriculture, environmental science, ...

  18. Google Search Mastery Basics

    Science.gov (United States)

    Hill, Paul; MacArthur, Stacey; Read, Nick

    2014-01-01

    Effective Internet search skills are essential with the continually increasing amount of information available on the Web. Extension personnel are required to find information to answer client questions and to conduct research on programs. Unfortunately, many lack the skills necessary to effectively navigate the Internet and locate needed…

  19. Search for intervalmodels

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    1996-01-01

    Methods are presented that carry out sorting of data according to some criteria, and investigate the possibilities of finding intervals that give separate models relative to the given data. The methods presented are more reliable than related clustering methods, because the search is carried out...

  20. Pentaquark searches with ALICE

    CERN Document Server

    Bobulska, Dana

    2016-01-01

    In this report we present the results of the data analysis for searching for possible invariant mass signals from pentaquarks in the ALICE data. Analysis was based on filtered data from real p-Pb events at psNN=5.02 TeV collected in 2013. The motivation for this project was the recent discovery of pentaquark states by the LHCb collaboration (c ¯ cuud resonance P+ c ) [1]. The search for similar not yet observed pentaquarks is an interesting research topic [2]. In this analysis we searched for a s ¯ suud pentaquark resonance P+ s and its possible decay channel to f meson and proton. The ALICE detector is well suited for the search of certain candidates thanks to its low material budget and strong PID capabilities. Additionally we might expect the production of such particles in ALICE as in heavy-ion and proton-ion collisions the thermal models describes well the particle yields and ratios [3]. Therefore it is reasonable to expect other species of hadrons, including also possible pentaquarks, to be produced w...

  1. Searching for Movies

    DEFF Research Database (Denmark)

    Bogers, Toine

    2015-01-01

    Despite a surge in popularity of work on casual leisure search, some leisure domains are still relatively underrepresented. Movies are good example of such a domain, which is peculiar given the popularity of movie-centered websites and discovery services such as IMDB, RottenTomatoes, and Netflix...

  2. SUSY Search at LHC

    CERN Document Server

    Xu, Da; The ATLAS collaboration

    2018-01-01

    Despite the absence of experimental evidence, weak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk gives an overview of the most recent SUSY searches in ATLAS and CMS experiments using 13 TeV ATLAS Run2 data.

  3. Search and Recommendation

    DEFF Research Database (Denmark)

    Bogers, Toine

    2014-01-01

    In just a little over half a century, the field of information retrieval has experienced spectacular growth and success, with IR applications such as search engines becoming a billion-dollar industry in the past decades. Recommender systems have seen an even more meteoric rise to success with wide...

  4. Search and imperative programming

    NARCIS (Netherlands)

    K.R. Apt (Krzysztof); A. Schaerf

    1996-01-01

    textabstractWe augment the expressive power of imperative programming in order to make it a more attractive vehicle for problems that involve search.The proposed additions are limited yet powerful and are inspired by the logic programming paradigm.We illustrate their use by presenting solutions to a

  5. THE SEARCH FOR CLUES

    OpenAIRE

    Landy Gobes

    2010-01-01

    This article is the keynote address given at the 4th International Integrative Psychotherapy Association Conference in Lake Bled, Slovenia. The author describes her journey in therapy and her experiences as a client searching for clues and unraveling what was “missing”.

  6. Excited lepton search

    International Nuclear Information System (INIS)

    Behrend, H.J.; Buerger, J.; Criegee, L.; Fenner, H.; Field, J.H.; Franke, G.; Fuster, J.; Holler, Y.; Meyer, J.; Schroeder, V.; Sindt, H.; Timm, U.; Winter, G.G.; Zimmermann, W.; Bussey, P.J.; Campbell, A.J.; Dainton, J.B.; Hendry, D.; McCurrach, G.; Scarr, J.M.; Skillicorn, I.O.; Smith, K.M.; Blobel, V.; Poppe, M.; Spitzer, H.; Boer, W. de; Buschhorn, G.; Christiansen, W.; Grindhammer, G.; Gunderson, B.; Kiesling, C.; Kotthaus, R.; Kroha, H.; Lueers, D.; Oberlack, H.; Sack, B.; Schacht, P.; Shooshtari, G.; Wiedenmann, W.; Cordier, A.; Davier, M.; Fournier, D.; Gaillard, M.; Grivaz, J.F.; Haissinski, J.; Janot, P.; Journe, V.; Le Diberder, F.; Ros, E.; Spadafora, A.; Veillet, J.J.; Aleksan, R.; Cozzika, G.; Ducros, Y.; Jarry, P.; Lavagne, Y.; Ould Saada, F.; Pamela, J.; Pierre, F.; Zacek, J.; Alexander, G.; Bella, G.; Gnat, Y.; Grunhaus, J.

    1986-02-01

    Using the CELLO detector at PETRA we have searched for excited leptons by studying e + e - interactions which yield p + p - γγ, l + l - γ and γγ final states, where l = 3, μ or τ. We observe good agreement with QED and set new limits on e*, μ*, and τ* production. (orig.)

  7. The Pulsar Search Collaboratory

    Science.gov (United States)

    Rosen, R.; Heatherly, S.; McLaughlin, M. A.; Kondratiev, V. I.; Boyles, J. R.; Wilson, M.; Lorimer, D. R.; Lynch, R.; Ransom, S.

    2010-01-01

    The Pulsar Search Collaboratory (PSC) (NSF #0737641) is a joint project between the National Radio Astronomy Observatory and West Virginia University designed to interest high school students in science, technology, engineering, and mathematics related career paths by helping them to conduct authentic scientific research. The 3 year PSC program,…

  8. Entity associations for search

    NARCIS (Netherlands)

    Reinanda, R.

    2017-01-01

    In this thesis, we investigate the broad problem of computing entity associations for search. Specifically, we consider three types of entity association: entity-entity, entity-document, and entity-aspect associations. We touch upon various domains, starting with specific domains such as the

  9. Flexible digital library search

    NARCIS (Netherlands)

    Windhouwer, M.; Schmidt, A.; Zwol, van R.; Petkovic, M.; Blok, H.E.; Dahanayake, A.; Gerhardt, W.

    2003-01-01

    In this chapter the development of a specialised search engine for a digital library is described. The proposed system architecture consists of three levels: the conceptual, the logical and the physical level. The conceptual level schema enables by its exposure of a domain specific schema

  10. Measuring Personalization of Web Search

    DEFF Research Database (Denmark)

    Hannak, Aniko; Sapiezynski, Piotr; Kakhki, Arash Molavi

    2013-01-01

    are simply unable to access information that the search engines’ algorithm decidesis irrelevant. Despitetheseconcerns, there has been little quantification of the extent of personalization in Web search today, or the user attributes that cause it. In light of this situation, we make three contributions...... as a result of searching with a logged in account and the IP address of the searching user. Our results are a first step towards understanding the extent and effects of personalization on Web search engines today....

  11. Search features of digital libraries

    Directory of Open Access Journals (Sweden)

    Alastair G. Smith

    2000-01-01

    Full Text Available Traditional on-line search services such as Dialog, DataStar and Lexis provide a wide range of search features (boolean and proximity operators, truncation, etc. This paper discusses the use of these features for effective searching, and argues that these features are required, regardless of advances in search engine technology. The literature on on-line searching is reviewed, identifying features that searchers find desirable for effective searching. A selective survey of current digital libraries available on the Web was undertaken, identifying which search features are present. The survey indicates that current digital libraries do not implement a wide range of search features. For instance: under half of the examples included controlled vocabulary, under half had proximity searching, only one enabled browsing of term indexes, and none of the digital libraries enable searchers to refine an initial search. Suggestions are made for enhancing the search effectiveness of digital libraries, for instance by: providing a full range of search operators, enabling browsing of search terms, enhancement of records with controlled vocabulary, enabling the refining of initial searches, etc.

  12. Berkeley automated supernova search

    Energy Technology Data Exchange (ETDEWEB)

    Kare, J.T.; Pennypacker, C.R.; Muller, R.A.; Mast, T.S.; Crawford, F.S.; Burns, M.S.

    1981-01-01

    The Berkeley automated supernova search employs a computer controlled 36-inch telescope and charge coupled device (CCD) detector to image 2500 galaxies per night. A dedicated minicomputer compares each galaxy image with stored reference data to identify supernovae in real time. The threshold for detection is m/sub v/ = 18.8. We plan to monitor roughly 500 galaxies in Virgo and closer every night, and an additional 6000 galaxies out to 70 Mpc on a three night cycle. This should yield very early detection of several supernovae per year for detailed study, and reliable premaximum detection of roughly 100 supernovae per year for statistical studies. The search should be operational in mid-1982.

  13. Searching for Lorentz violation

    International Nuclear Information System (INIS)

    Allen, Roland E.; Yokoo, Seiichirou

    2004-01-01

    Astrophysical, terrestrial, and space-based searches for Lorentz violation are very briefly reviewed. Such searches are motivated by the fact that all superunified theories (and other theories that attempt to include quantum gravity) have some potential for observable violations of Lorentz invariance. Another motivation is the exquisite sensitivity of certain well-designed experiments and observations to particular forms of Lorentz violation. We also review some new predictions of a specific Lorentz-violating theory: If a fundamental energy m-bar c2 in this theory lies below the usual GZK cutoff E GZK , the cutoff is shifted to infinite energy; i.e., it no longer exists. On the other hand, if m-bar c2 lies above E GZK , there is a high-energy branch of the fermion dispersion relation which provides an alternative mechanism for super-GZK cosmic-ray protons

  14. Berkeley automated supernova search

    International Nuclear Information System (INIS)

    Kare, J.T.; Pennypacker, C.R.; Muller, R.A.; Mast, T.S.

    1981-01-01

    The Berkeley automated supernova search employs a computer controlled 36-inch telescope and charge coupled device (CCD) detector to image 2500 galaxies per night. A dedicated minicomputer compares each galaxy image with stored reference data to identify supernovae in real time. The threshold for detection is m/sub v/ = 18.8. We plan to monitor roughly 500 galaxies in Virgo and closer every night, and an additional 6000 galaxies out to 70 Mpc on a three night cycle. This should yield very early detection of several supernovae per year for detailed study, and reliable premaximum detection of roughly 100 supernovae per year for statistical studies. The search should be operational in mid-1982

  15. Search for Hidden Particles

    CERN Multimedia

    Solovev, V

    The SHiP Experiment is a new general-purpose fixed target facility at the SPS to search for hidden particles as predicted by a very large number of recently elaborated models of Hidden Sectors which are capable of accommodating dark matter, neutrino oscillations, and the origin of the full baryon asymmetry in the Universe. Specifically, the experiment is aimed at searching for very weakly interacting long lived particles including Heavy Neutral Leptons - right-handed partners of the active neutrinos; light supersymmetric particles - sgoldstinos, etc.; scalar, axion and vector portals to the hidden sector. The high intensity of the SPS and in particular the large production of charm mesons with the 400 GeV beam allow accessing a wide variety of light long-lived exotic particles of such models and of SUSY. Moreover, the facility is ideally suited to study the interactions of tau neutrinos.

  16. Exotics searches in ATLAS

    CERN Document Server

    Wang, Renjie; The ATLAS collaboration

    2017-01-01

    Many theories beyond the Standard Model predict new physics accessible by the LHC. The ATLAS experiment all have rigorous search programs ongoing with the aim to find indications for new physics involving state of the art analysis techniques. This talk reports on new results obtained using the pp collision data sample collected in 2015 and 2016 at the LHC with a centre-of-mass energy of 13 TeV.

  17. Optimal intermittent search strategies

    International Nuclear Information System (INIS)

    Rojo, F; Budde, C E; Wio, H S

    2009-01-01

    We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion

  18. Search Analytics for Your Site

    CERN Document Server

    Rosenfeld, Louis

    2011-01-01

    Any organization that has a searchable web site or intranet is sitting on top of hugely valuable and usually under-exploited data: logs that capture what users are searching for, how often each query was searched, and how many results each query retrieved. Search queries are gold: they are real data that show us exactly what users are searching for in their own words. This book shows you how to use search analytics to carry on a conversation with your customers: listen to and understand their needs, and improve your content, navigation and search performance to meet those needs.

  19. evaluating search effectiveness of some selected search engines

    African Journals Online (AJOL)

    Precision, relative recall and response time were considered for this ... a total of 24 search queries were sampled based on information queries, .... searching process and results, although there are other ... Q3.2 Software prototype model.

  20. Diphoton searches in ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00213273; The ATLAS collaboration

    2016-01-01

    Searches for new resonances decaying into two photons in the ATLAS experiment at the LHC are described. The analysis is based on $pp$ collision data corresponding to an integrated luminosity of 3.2 fb$^{-1}$ at $\\sqrt{s}$ = 13 TeV recorded in 2015. Two different searches are performed, one targeted for a spin-2 particle, using Randall-Sundrum graviton states as a benchmark model, and one optimized for a spin-0 particle. The most significant deviation from the background predictions is observed at a diphoton invariant mass around 750 GeV with local significances of 3.6 and 3.9 standard deviations in the searches optimized for a spin-2 and spin-0 particle, respectively. The global significances are estimated to be 1.8 and 2.0 standard deviations. The consistency between the data collected at 13 TeV and 8 TeV is also evaluated. Limits on the production cross-section for the two benchmark resonances are reported.

  1. Search for fractional charge

    International Nuclear Information System (INIS)

    Turner, R.E.

    1984-01-01

    A search was made for fractional charges of the form Z plus two-thirds e, where Z is an integer. It was assumed that the charges exist in natural form bound with other fractional charges in neutral molecules. It was further assumed that these neutral molecules are present in air. Two concentration schemes were employed. One sample was derived from the waste gases from a xenon distillation plant. This assumes that high mass, low vapor pressure components of air are concentrated along with the xenon. The second sample involved ionizing air, allowing a brief recombination period, and then collecting residual ions on the surface of titanium discs. Both samples were analyzed at the University of Rochester in a system using a tandem Van de Graff to accelerate particles through an essentially electrostatic beam handling system. The detector system employed both a Time of Flight and an energy-sensitive gas ionization detector. In the most sensitive mode of analysis, a gas absorber was inserted in the beam path to block the intense background. The presence of an absorber limited the search to highly penetrating particles. Effectively, this limited the search to particles with low Z and masses greater than roughly fifty GeV. The final sensitivities attained were on the order of 1 x 10 -20 for the ionized air sample and 1 x 10 -21 for the gas sample. A discussion of the caveats that could reduce the actual level of sensitivity is included

  2. MINOS Sterile Neutrino Search

    Energy Technology Data Exchange (ETDEWEB)

    Koskinen, David Jason [Univ. College London, Bloomsbury (United Kingdom)

    2009-02-01

    The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline accelerator neutrino experiment designed to measure properties of neutrino oscillation. Using a high intensity muon neutrino beam, produced by the Neutrinos at Main Injector (NuMI) complex at Fermilab, MINOS makes two measurements of neutrino interactions. The first measurement is made using the Near Detector situated at Fermilab and the second is made using the Far Detector located in the Soudan Underground laboratory in northern Minnesota. The primary goal of MINOS is to verify, and measure the properties of, neutrino oscillation between the two detectors using the v μ→ Vτ transition. A complementary measurement can be made to search for the existence of sterile neutrinos; an oft theorized, but experimentally unvalidated particle. The following thesis will show the results of a sterile neutrino search using MINOS RunI and RunII data totaling ~2.5 x 1020 protons on target. Due to the theoretical nature of sterile neutrinos, complete formalism that covers transition probabilities for the three known active states with the addition of a sterile state is also presented.

  3. Accelerated Profile HMM Searches.

    Directory of Open Access Journals (Sweden)

    Sean R Eddy

    2011-10-01

    Full Text Available Profile hidden Markov models (profile HMMs and probabilistic inference methods have made important contributions to the theory of sequence database homology search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs, the "multiple segment Viterbi" (MSV algorithm. The MSV algorithm computes an optimal sum of multiple ungapped local alignment segments using a striped vector-parallel approach previously described for fast Smith/Waterman alignment. MSV scores follow the same statistical distribution as gapped optimal local alignment scores, allowing rapid evaluation of significance of an MSV score and thus facilitating its use as a heuristic filter. I also describe a 20-fold acceleration of the standard profile HMM Forward/Backward algorithms using a method I call "sparse rescaling". These methods are assembled in a pipeline in which high-scoring MSV hits are passed on for reanalysis with the full HMM Forward/Backward algorithm. This accelerated pipeline is implemented in the freely available HMMER3 software package. Performance benchmarks show that the use of the heuristic MSV filter sacrifices negligible sensitivity compared to unaccelerated profile HMM searches. HMMER3 is substantially more sensitive and 100- to 1000-fold faster than HMMER2. HMMER3 is now about as fast as BLAST for protein searches.

  4. Search costs and efficiency : Do unemployed workers search enough?

    NARCIS (Netherlands)

    Gautier, Pieter A.; Moraga González, José; Wolthoff, Ronald P.

    Many labor market policies affect the marginal benefits and costs of job search. The impact and desirability of such policies depend on the distribution of search costs. In this paper, we provide an equilibrium framework for identifying the distribution of search costs and we apply it to the Dutch

  5. Subject search study. Final report

    International Nuclear Information System (INIS)

    Todeschini, C.

    1995-01-01

    The study gathered information on how users search the database of the International Nuclear Information System (INIS), using indicators such as Subject categories, Controlled terms, Subject headings, Free-text words, combinations of the above. Users participated from the Australian, French, Russian and Spanish INIS Centres, that have different national languages. Participants, both intermediaries and end users, replied to a questionnaire and executed search queries. The INIS Secretariat at the IAEA also participated. A protocol of all search strategies used in actual searches in the database was kept. The thought process for Russian and Spanish users is predominantly non-English and also the actual initial search formulation is predominantly non-English among Russian and Spanish users while it tends to be more in English among French users. A total of 1002 searches were executed by the five INIS centres including the IAEA. The search protocols indicate the following search behaviour: 1) free text words represent about 40% of search points on an average query; 2) descriptors used as search keys have the widest range as percentage of search points, from a low of 25% to a high of 48%; 3) search keys consisting of free text that coincides with a descriptor account for about 15% of search points; 4) Subject Categories are not used in many searches; 5) free text words are present as search points in about 80% of all searches; 6) controlled terms (descriptors) are used very extensively and appear in about 90% of all searches; 7) Subject Headings were used in only a few percent of searches. From the results of the study one can conclude that there is a greater reluctance on the part of non-native English speakers in initiating their searches by using free text word searches. Also: Subject Categories are little used in searching the database; both free text terms and controlled terms are the predominant types of search keys used, whereby the controlled terms are used more

  6. ’n Vergelyking van die Mollusca-diversiteit in die Mooirivier (Noordwes-Provinsie soos gevind met opnames wat gemaak is in 1963 en weer 50 jaar later

    Directory of Open Access Journals (Sweden)

    Cornelius T. Wolmarans

    2015-02-01

    Full Text Available Die hoogste getal gedokumenteerde uitsterwings van enige belangrike taksonomiese groepword aan die Mollusca toegedig. Faktore wat hoofsaaklik hiervoor verantwoordelik is, sluitonder meer omgewingsveranderinge en antropogeniese impakte in wat tot die tot niet gaanvan die habitat aanleiding gee. Daarbenewens is die bewaringstatus van minder as 2% van dieongeveer 7000 molluskspesies wêreldwyd bekend tot dusver nog nie behoorlik geassesseernie. Die doel van die huidige ondersoek wat in 2014 uitgevoer is, was om die molluskdiversiteitvan die Mooirivier met die resultate van 1963 te vergelyk. Dit is gedoen deur ’n opnameuit te voer van die molluskdiversiteit by dieselfde lokaliteite as in 1963. Twee opnames isgemaak tydens ’n vroeë- en laatlaagvloeiperiode in 2014 by agt lokaliteite wat met dié vandie 1963-opnames ooreenstem. Die pH, elektriese geleiding (EG en temperatuur is ook byelk van die lokaliteite gemeet. Die identiteit van die 14 slakspesies wat in 1963 gevind is, hetooreengestem met 14 van die 15 in 2014. Die uitheemse indringerspesie Physa acuta is tydensdie 2014-opname vir die eerste keer in hierdie rivier gevind, waarskynlik weens ’n toename inorganiese verryking. In die 1963-opname is Burnupia mooiensis en Pisidium langlyanum by diemeeste lokaliteite gevind, en in 2014 Gyraulus connollyi en Ferrissia cawstoni. Die meeste van diemolluske uit hierdie gebied wat voorheen op rekord gestel is, is in 2014 gevind. Die pH watin 2014 ’n geringe tot aansienlike verlaging getoon het, word aan mynversuring toegeskryfen het nie ’n merkbare invloed op die molluskdiversiteit gehad nie. Die hoër elektriesegeleiding wat tydens die 2014-opname gemeet is, het vanweë die verdraagsaamheid vanvarswatermolluske in hierdie verband, ook geen verandering in die molluskdiversiteit teweeggebring nie. Die temperatuur was in die laatlaagvloei deurgaans hoër. Ondanks die feit dathierdie studies vyf dekades uitmekaar gedoen is en antropogeniese impakte

  7. Intragenomic sequence variation at the ITS1 - ITS2 region and at the 18S and 28S nuclear ribosomal DNA genes of the New Zealand mud snail, Potamopyrgus antipodarum (Hydrobiidae: mollusca)

    Science.gov (United States)

    Hoy, Marshal S.; Rodriguez, Rusty J.

    2013-01-01

    Molecular genetic analysis was conducted on two populations of the invasive non-native New Zealand mud snail (Potamopyrgus antipodarum), one from a freshwater ecosystem in Devil's Lake (Oregon, USA) and the other from an ecosystem of higher salinity in the Columbia River estuary (Hammond Harbor, Oregon, USA). To elucidate potential genetic differences between the two populations, three segments of nuclear ribosomal DNA (rDNA), the ITS1-ITS2 regions and the 18S and 28S rDNA genes were cloned and sequenced. Variant sequences within each individual were found in all three rDNA segments. Folding models were utilized for secondary structure analysis and results indicated that there were many sequences which contained structure-altering polymorphisms, which suggests they could be nonfunctional pseudogenes. In addition, analysis of molecular variance (AMOVA) was used for hierarchical analysis of genetic variance to estimate variation within and among populations and within individuals. AMOVA revealed significant variation in the ITS region between the populations and among clones within individuals, while in the 5.8S rDNA significant variation was revealed among individuals within the two populations. High levels of intragenomic variation were found in the ITS regions, which are known to be highly variable in many organisms. More interestingly, intragenomic variation was also found in the 18S and 28S rDNA, which has rarely been observed in animals and is so far unreported in Mollusca. We postulate that in these P. antipodarum populations the effects of concerted evolution are diminished due to the fact that not all of the rDNA genes in their polyploid genome should be essential for sustaining cellular function. This could lead to a lessening of selection pressures, allowing mutations to accumulate in some copies, changing them into variant sequences.                   

  8. Switching strategies to optimize search

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2016-01-01

    Search strategies are explored when the search time is fixed, success is probabilistic and the estimate for success can diminish with time if there is not a successful result. Under the time constraint the problem is to find the optimal time to switch a search strategy or search location. Several variables are taken into account, including cost, gain, rate of success if a target is present and the probability that a target is present. (paper: interdisciplinary statistical mechanics)

  9. Search Engines for Tomorrow's Scholars

    Science.gov (United States)

    Fagan, Jody Condit

    2011-01-01

    Today's scholars face an outstanding array of choices when choosing search tools: Google Scholar, discipline-specific abstracts and index databases, library discovery tools, and more recently, Microsoft's re-launch of their academic search tool, now dubbed Microsoft Academic Search. What are these tools' strengths for the emerging needs of…

  10. Undergraduate Students' Information Search Practices

    Science.gov (United States)

    Nikolopoulou, Kleopatra; Gialamas, Vasilis

    2011-01-01

    This paper investigates undergraduate students' information search practices. The subjects were 250 undergraduate students from two university departments in Greece, and a questionnaire was used to document their search practices. The results showed that the Web was the primary information system searched in order to find information for…

  11. Dark Matter Searches at LHC

    CERN Document Server

    Terashi, Koji; The ATLAS collaboration

    2017-01-01

    This talk will present dark matter searches at the LHC in the PIC2017 conference. The main emphasis is placed on the direct dark matter searches while the interpretation of searches for SUSY and invisible Higgs signals for the dark matter is also presented.

  12. Search for scalar muons

    International Nuclear Information System (INIS)

    Bartel, W.; Becker, L.; Bowdery, C.; Cords, D.; Felst, R.; Haidt, D.; Knies, G.; Krehbiel, H.; Meinke, R.; Naroska, B.; Olsson, J.; Steffen, P.; Junge, H.; Schmidt, D.; Laurikainen, P.; Dietrich, G.; Hagemann, J.; Heinzelmann, G.; Kado, H.; Kleinwort, C.; Kuhlen, M.; Meier, K.; Petersen, A.; Ramcke, R.; Schneekloth, U.; Weber, G.; Allison, J.; Baines, J.; Ball, A.H.; Barlow, R.J.; Chrin, J.; Duerdoth, I.P.; Greenshaw, T.; Hill, P.; Loebinger, F.K.; Macbeth, A.A.; McCann, H.; Mills, H.E.; Murphy, P.G.; Stephens, K.; Warming, P.; Glasser, R.G.; Sechi-Zorn, B.; Skard, J.A.J.; Wagner, S.R.; Zorn, G.T.; Cartwright, S.L.; Clarke, D.; Marshall, R.; Middleton, R.P.; Whittaker, J.B.; Kawamoto, T.; Kobayashi, T.; Mashimo, T.; Minowa, M.; Takeda, H.; Takeshita, T.; Yamada, S.

    1984-12-01

    The supersymmetric partner of the muon was searched for in a systematic way. No candidate was found and 95% CL limits on its mass were given for different cases. If it is stable, the limit is 20.9 GeV/c 2 . If it decays into a muon and an invisible low mass particle, the limit is 20.3 GeV/c 2 . If it decays into a muon and an unstable neutral particle which decays further into a photon and an invisible massless particles, the limit is 19.2 GeV/c 2 . (orig.)

  13. Search for black holes

    International Nuclear Information System (INIS)

    Cherepashchuk, Anatolii M

    2003-01-01

    Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)

  14. Search for scalar mesons

    International Nuclear Information System (INIS)

    Pennington, M.R.

    1989-01-01

    The search for I = 0 0 ++ mesons is described. The crucial role played by the states in the 1 GeV region is highlighted. An analysis program that with unimpeachable data would produce definitive results on these is outlined and shown with present data to provide prima facie evidence for dynamics beyond that of the quark model. The authors briefly speculate on the current status of the lowest mass scalar mesons and discuss how experiment can resolve the unanswered issues. 30 references, 6 figures, 1 table

  15. A New Search for $ \

    CERN Multimedia

    Dore, U; Kodama, K; Ushida, N; Loverre, P F

    2002-01-01

    % WA95\\\\ \\\\ The question whether neutrino flavours mix at some level - and the related question whether neutrinos have non-zero mass - is one of the remaining great challenges of experimental physics. Neutrinos from supernovae, from the sun, from the earth's atmosphere, from nuclear reactors and from radioactive decays are currently under study; in this frame, experiments using accelerators play a privileged role because the well known neutrino source properties allow high precision measurements and background control.\\\\ \\\\The main goal of the CHORUS experiment is to search for neutrino oscillations in the $\

  16. ATLAS Exotic Searches

    CERN Document Server

    Bousson, Nicolas

    2012-01-01

    Thanks to the outstanding performance of the Large Hadron Collider (LHC) that delivered more than 2 fb^-1 of proton-proton collision data at center-of-mass energy of 7 TeV, the ATLAS experiment has been able to explore a wide range of exotic models trying to address the questions unanswered by the Standard Model of particle physics. Searches for leptoquarks, new heavy quarks, vector-like quarks, black holes, hidden valley and contact interactions are reviewed in these proceedings.

  17. Pentaquark Searches at Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Patrizia

    2007-01-01

    Since LEPS collaboration reported the first evidence for a S=+1 baryon resonance in early 2003 with a mass of 1.54 GeV, dubbed Θ+, more than ten experiments have confirmed this exotic state, among these two carried out at Jefferson Laboratory. At the same time, there are a number of experiments, mostly at high energies, that report null results. To try to clarify this situation, during the past year, The CLAS Collaboration at Jefferson Laboratory has undertaken a second generation high-statistics experimental program to search for exotics baryons. Here the preliminary results from these experiments are reported.

  18. Higgs Searches at DØ

    Science.gov (United States)

    Owen, Mark

    2009-09-01

    The Higgs boson is essential to achieve electroweak symmetry breaking in the Standard Model. Results on searches for the Higgs boson using data collected in pbar p collisions at √ s = 1.96 {TeV} with the DØ detector at the Fermilab Teva-tron collider are presented. The data, corresponding to integrated luminosities between 1 fb-1 and 2 fb-1 show no excess above the expected backgrounds and as such upper limits on the production cross section of Higgs bosons are set at the 95% confidence level.

  19. Optimal intermittent search strategies

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, F; Budde, C E [FaMAF, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC E-39005 Santander (Spain)

    2009-03-27

    We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion.

  20. Learning about Job Search

    DEFF Research Database (Denmark)

    Altmann, Steffen; Falk, Armin; Jäger, Simon

    strategies and the consequences of unemployment, and motivated them to actively look for new employment. We study the causal impact of the brochure by comparing labor market outcomes of treated and untreated job seekers in administrative data containing comprehensive information on individuals’ employment...... findings indicate that targeted information provision can be a highly effective policy tool in the labor market.......We conduct a large-scale field experiment in the German labor market to investigate how information provision affects job seekers’ employment prospects and labor market outcomes. Individuals assigned to the treatment group of our experiment received a brochure that informed them about job search...

  1. Search Engine Optimization

    CERN Document Server

    Davis, Harold

    2006-01-01

    SEO--short for Search Engine Optimization--is the art, craft, and science of driving web traffic to web sites. Web traffic is food, drink, and oxygen--in short, life itself--to any web-based business. Whether your web site depends on broad, general traffic, or high-quality, targeted traffic, this PDF has the tools and information you need to draw more traffic to your site. You'll learn how to effectively use PageRank (and Google itself); how to get listed, get links, and get syndicated; and much more. The field of SEO is expanding into all the possible ways of promoting web traffic. This

  2. Search Databases and Statistics

    DEFF Research Database (Denmark)

    Refsgaard, Jan C; Munk, Stephanie; Jensen, Lars J

    2016-01-01

    having strengths and weaknesses that must be considered for the individual needs. These are reviewed in this chapter. Equally critical for generating highly confident output datasets is the application of sound statistical criteria to limit the inclusion of incorrect peptide identifications from database...... searches. Additionally, careful filtering and use of appropriate statistical tests on the output datasets affects the quality of all downstream analyses and interpretation of the data. Our considerations and general practices on these aspects of phosphoproteomics data processing are presented here....

  3. Searching for uranium

    International Nuclear Information System (INIS)

    Spaargaren, F.A.

    1988-01-01

    In the not-so-distant past, the search for uranium usually followed a conceptual approach in which an unexplored terrain was selected because of its presumed similarities with one that is known to contain one or more deposits. A description, in general terms, is given of the methodology adopted during the different stages of the exploration programme, up to the point of a discovery. Three case histories prove that, in order to reach this point, a certain amount of improvisation and luck is usually required. (author)

  4. Searching for dark matter

    Science.gov (United States)

    Mateo, Mario

    1994-01-01

    Three teams of astronomers believe they have independently found evidence for dark matter in our galaxy. A brief history of the search for dark matter is presented. The use of microlensing-event observation for spotting dark matter is described. The equipment required to observe microlensing events and three groups working on dark matter detection are discussed. The three groups are the Massive Compact Halo Objects (MACHO) Project team, the Experience de Recherche d'Objets Sombres (EROS) team, and the Optical Gravitational Lensing Experiment (OGLE) team. The first apparent detections of microlensing events by the three teams are briefly reported.

  5. Dark Matter Searches

    International Nuclear Information System (INIS)

    Moriyama, Shigetaka

    2008-01-01

    Recent cosmological as well as historical observations of rotational curves of galaxies strongly suggest the existence of dark matter. It is also widely believed that dark matter consists of unknown elementary particles. However, astrophysical observations based on gravitational effects alone do not provide sufficient information on the properties of dark matter. In this study, the status of dark matter searches is investigated by observing high-energy neutrinos from the sun and the earth and by observing nuclear recoils in laboratory targets. The successful detection of dark matter by these methods facilitates systematic studies of its properties. Finally, the XMASS experiment, which is due to start at the Kamioka Observatory, is introduced

  6. Pentaquark Searches at JLab

    International Nuclear Information System (INIS)

    Rossi, P.

    2007-01-01

    Since LEPS collaboration reported the first evidence for a S=+1 baryon resonance in early 2003 with a mass of 1.54 GeV, dubbed Θ + , more than ten experiments have confirmed this exotic state, among these two carried out at Jefferson Laboratory. At the same time, there are a number of experiments, mostly at high energies, that report null results. To try to clarify this situation, during the past year, The CLAS Collaboration at Jefferson Laboratory has undertaken a second generation high-statistics experimental program to search for exotics baryons. Here the preliminary results from these experiments are reported

  7. Multimedia Search Engines : Concept, Performance, and Types

    OpenAIRE

    Sayed Rabeh Sayed

    2005-01-01

    A Research about multimedia search engines, it starts with definition of search engines at general and multimedia search engines, then explains how they work, and divided them into: Video search engines, Images search engines, and Audio search engines. Finally, it reviews a samples to multimedia search engines.

  8. Heuristic Search Theory and Applications

    CERN Document Server

    Edelkamp, Stefan

    2011-01-01

    Search has been vital to artificial intelligence from the very beginning as a core technique in problem solving. The authors present a thorough overview of heuristic search with a balance of discussion between theoretical analysis and efficient implementation and application to real-world problems. Current developments in search such as pattern databases and search with efficient use of external memory and parallel processing units on main boards and graphics cards are detailed. Heuristic search as a problem solving tool is demonstrated in applications for puzzle solving, game playing, constra

  9. Search For Trapped Antihydrogen

    CERN Document Server

    Andresen, Gorm B.; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D.; Bray, Crystal C.; Butler, Eoin; Cesar, Claudio L.; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C.; Gill, David R.; Hangst, Jeffrey S.; Hardy, Walter N.; Hayano, Ryugo S.; Hayden, Michael E.; Humphries, Andrew J.; Hydomako, Richard; Jonsell, Svante; Jorgensen, Lars V.; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M.; So, Chukman; Storey, James W.; Thompson, Robert I.; van der Werf, Dirk P.; Wilding, Dean; Wurtele, Jonathan S.; Yamazaki, Yasunori

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

  10. Searching for heavy leptons

    International Nuclear Information System (INIS)

    Perl, M.L.

    1979-11-01

    This frankly speculative paper discusses ways in which leptons heavier than the tau (if they exist) might be found. The status of the tau is briefly reviewed, and methods for searching for sequential charged leptons beyond the tau and other charged leptons at PEP, PETRA, and CESR are sketched. Charged leptons with mass greater than 20 GeV/c 2 might be found at proton accelerators in hadron-hadron, photon-hadron, or ν-hadron collisions. Unstable, neutral heavy leptons might have unique, conserved lepton number or nonunique lepton number. The most difficult leptons to detect are stable neutral heavy leptons; nevertheless, a possible detection method is suggested. The obvious solution to seeking the postulated leptons is an e + e - colliding beam storage ring with c.m. energy = several hundred GeV. Until such a machine is built, one can employ Z 0 → L + + L - ; the use of R/sub Z 0 / and GAMMA/sub Z 0 / in this connection is discussed. If heavier Z 0 's exist, the heavy lepton search can be extended to higher energies. Another solution for producing these leptons involves the use of clashing e + e - linear accelerators. Characteristics of storage rings are compared with those of clashing linacs; a general description is given of the proposed SLAC Linac-Collider, along with the physics that could be done at such a machine. 6 figures

  11. Stability of cascade search

    Energy Technology Data Exchange (ETDEWEB)

    Fomenko, Tatiana N [M. V. Lomonosov Moscow State University, Faculty of Computational Mathematics and Cybernetics, Moscow (Russian Federation)

    2010-10-22

    We find sufficient conditions on a searching multi-cascade for a modification of the set of limit points of the cascade that satisfy an assessing inequality for the distance from each of these points to the initial point to be small, provided that the modifications of the initial point and the initial set-valued functionals or maps used to construct the multi-cascade are small. Using this result, we prove the stability (in the above sense) of the cascade search for the set of common pre-images of a closed subspace under the action of n set-valued maps, n{>=}1 (in particular, for the set of common roots of these maps and for the set of their coincidences). For n=2 we obtain generalizations of some results of A. V. Arutyunov; the very statement of the problem comes from a recent paper of his devoted to the study of the stability of the subset of coincidences of a Lipschitz map and a covering map.

  12. One visual search, many memory searches: An eye-tracking investigation of hybrid search.

    Science.gov (United States)

    Drew, Trafton; Boettcher, Sage E P; Wolfe, Jeremy M

    2017-09-01

    Suppose you go to the supermarket with a shopping list of 10 items held in memory. Your shopping expedition can be seen as a combination of visual search and memory search. This is known as "hybrid search." There is a growing interest in understanding how hybrid search tasks are accomplished. We used eye tracking to examine how manipulating the number of possible targets (the memory set size [MSS]) changes how observers (Os) search. We found that dwell time on each distractor increased with MSS, suggesting a memory search was being executed each time a new distractor was fixated. Meanwhile, although the rate of refixation increased with MSS, it was not nearly enough to suggest a strategy that involves repeatedly searching visual space for subgroups of the target set. These data provide a clear demonstration that hybrid search tasks are carried out via a "one visual search, many memory searches" heuristic in which Os examine items in the visual array once with a very low rate of refixations. For each item selected, Os activate a memory search that produces logarithmic response time increases with increased MSS. Furthermore, the percentage of distractors fixated was strongly modulated by the MSS: More items in the MSS led to a higher percentage of fixated distractors. Searching for more potential targets appears to significantly alter how Os approach the task, ultimately resulting in more eye movements and longer response times.

  13. Policy implications for familial searching.

    Science.gov (United States)

    Kim, Joyce; Mammo, Danny; Siegel, Marni B; Katsanis, Sara H

    2011-11-01

    In the United States, several states have made policy decisions regarding whether and how to use familial searching of the Combined DNA Index System (CODIS) database in criminal investigations. Familial searching pushes DNA typing beyond merely identifying individuals to detecting genetic relatedness, an application previously reserved for missing persons identifications and custody battles. The intentional search of CODIS for partial matches to an item of evidence offers law enforcement agencies a powerful tool for developing investigative leads, apprehending criminals, revitalizing cold cases and exonerating wrongfully convicted individuals. As familial searching involves a range of logistical, social, ethical and legal considerations, states are now grappling with policy options for implementing familial searching to balance crime fighting with its potential impact on society. When developing policies for familial searching, legislators should take into account the impact of familial searching on select populations and the need to minimize personal intrusion on relatives of individuals in the DNA database. This review describes the approaches used to narrow a suspect pool from a partial match search of CODIS and summarizes the economic, ethical, logistical and political challenges of implementing familial searching. We examine particular US state policies and the policy options adopted to address these issues. The aim of this review is to provide objective background information on the controversial approach of familial searching to inform policy decisions in this area. Herein we highlight key policy options and recommendations regarding effective utilization of familial searching that minimize harm to and afford maximum protection of US citizens.

  14. Beyond the search surface: visual search and attentional engagement.

    Science.gov (United States)

    Duncan, J; Humphreys, G

    1992-05-01

    Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (Duncan & Humphreys, 1989) in which feature and conjunction search are basically similar. Here the latter account is noted to have 2 distinct levels: (a) a summary of search findings in terms of stimulus similarities, and (b) a theory of how visual attention is brought to bear on relevant objects. Working at the 1st level, Treisman found that even when similarities were calibrated and controlled, conjunction search was much harder than feature search. The theory, however, can only really be tested at the 2nd level, because the 1st is an approximation. An account of the findings is developed at the 2nd level, based on the 2 processes of input-template matching and spreading suppression. New data show that, when both of these factors are controlled, feature and conjunction search are equally difficult. Possibilities for unification of the alternative views are considered.

  15. Higgs searches with CMS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    The excellent performances of the LHC in the 2011 run are setting the grounds for the final chase of the Higgs boson. The CMS experiment is recording high quality data that are being thoroughly scrutinized. Several decay channels are investigated to probe the entire possible Higgs mass spectrum, from 110 to 600 GeV/c^2. The study of the first 1.5/fb of collected data places already tight limits and excludes large fractions of the Higgs mass range, leaving however still open the search in the theoretically favored low mass region. In this seminar we will report on the diverse CMS analyses that yield to such results describing the experimental challenges that each had to meet.

  16. Open Search Environments: The Free Alternative to Commercial Search Services

    Directory of Open Access Journals (Sweden)

    Adrian O'Riordan

    2014-06-01

    Full Text Available Open search systems present a free and less restricted alternative to commercial search services. This paper explores the space of open search technology looking in particular at the issue of interoperability. A description of current protocols and formats for engineering open search applications is presented. The suitability of these technologies and issues around their adoption and operation are discussed. This open search approach is especially proving a fitting choice in applications involving the harvesting of resources and information integration. Principal among the technological solutions are OpenSearch and SRU. OpenSearch and SRU implement a federated model to enable existing and new search engines and search clients communicate. Applications and instances where Opensearch and SRU can be combined are presented. Other relevant technologies such as OpenURL, Apache Solr, and OAI-PMH are also discussed. The deployment of these freely licensed open standards in digital library applications is now a genuine alternative to commercial or proprietary systems.

  17. Search 3.0: Present, Personal, Precise

    Science.gov (United States)

    Spivack, Nova

    The next generation of Web search is already beginning to emerge. With it we will see several shifts in the way people search, and the way major search engines provide search functionality to consumers.

  18. A Search Model of Discouragement

    DEFF Research Database (Denmark)

    Rosholm, Michael; Toomet, Ott

    Discouragement is a process occurring during an unemployment spell. As the spell prolongs, an individual gradually realises that the returns to search can no longer outweigh search costs, and hence she may eventually leave the labour force. This is analysed theoretically in a framework...... of unemployed search. We construct a search model, which is stationary from the point of view of the individual, but which has nonstationary features. Namely, the unemployed worker is occasionally hit by shocks leading to a decline in job offer arrival rates. These shocks can be due to stigmatisation...... or to psychological consequences of unemployement affecting search effectiveness. This model enables us to analyse the issue of discouragement, as the returns to search will gradually decline. Even so, the model is actually stationary from the point of view of the individual, which implies that many interesting...

  19. Clinician search behaviors may be influenced by search engine design.

    Science.gov (United States)

    Lau, Annie Y S; Coiera, Enrico; Zrimec, Tatjana; Compton, Paul

    2010-06-30

    Searching the Web for documents using information retrieval systems plays an important part in clinicians' practice of evidence-based medicine. While much research focuses on the design of methods to retrieve documents, there has been little examination of the way different search engine capabilities influence clinician search behaviors. Previous studies have shown that use of task-based search engines allows for faster searches with no loss of decision accuracy compared with resource-based engines. We hypothesized that changes in search behaviors may explain these differences. In all, 75 clinicians (44 doctors and 31 clinical nurse consultants) were randomized to use either a resource-based or a task-based version of a clinical information retrieval system to answer questions about 8 clinical scenarios in a controlled setting in a university computer laboratory. Clinicians using the resource-based system could select 1 of 6 resources, such as PubMed; clinicians using the task-based system could select 1 of 6 clinical tasks, such as diagnosis. Clinicians in both systems could reformulate search queries. System logs unobtrusively capturing clinicians' interactions with the systems were coded and analyzed for clinicians' search actions and query reformulation strategies. The most frequent search action of clinicians using the resource-based system was to explore a new resource with the same query, that is, these clinicians exhibited a "breadth-first" search behaviour. Of 1398 search actions, clinicians using the resource-based system conducted 401 (28.7%, 95% confidence interval [CI] 26.37-31.11) in this way. In contrast, the majority of clinicians using the task-based system exhibited a "depth-first" search behavior in which they reformulated query keywords while keeping to the same task profiles. Of 585 search actions conducted by clinicians using the task-based system, 379 (64.8%, 95% CI 60.83-68.55) were conducted in this way. This study provides evidence that

  20. LHCb Exotica and Higgs searches

    CERN Multimedia

    Lucchesi, Donatella

    2016-01-01

    The unique phase space coverage and features of the LHCb detector at the LHC makes it an ideal environment to probe complementary New Physics parameter regions. In particular, recently developed jet tagging algorithms are ideal for searches involving $b$ and $c$ jets. This poster will review different jet-related exotica searches together with the efforts in the search for a Higgs boson decaying to a pair of heavy quarks.

  1. Guided Search for Triple Conjunctions

    OpenAIRE

    Nordfang, Maria; Wolfe, Jeremy M

    2014-01-01

    A key tenet of Feature Integration Theory and related theories such as Guided Search (GS) is that the binding of basic features requires attention. This would seem to predict that conjunctions of features of objects that have not been attended should not influence search. However, Found (1998) reported that an irrelevant feature (size) improved the efficiency of search for a color × orientation conjunction if it was correlated with the other two features across the display compared to the cas...

  2. Policy implications for familial searching

    OpenAIRE

    Kim, Joyce; Mammo, Danny; Siegel, Marni B; Katsanis, Sara H

    2011-01-01

    Abstract In the United States, several states have made policy decisions regarding whether and how to use familial searching of the Combined DNA Index System (CODIS) database in criminal investigations. Familial searching pushes DNA typing beyond merely identifying individuals to detecting genetic relatedness, an application previously reserved for missing persons identifications and custody battles. The intentional search of CODIS for partial matches to an item of evidence offers law enforce...

  3. Dark Matter Searches at ATLAS

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The astrophysical evidence of dark matter provides some of the most compelling clues to the nature of physics beyond the Standard Model. From these clues, ATLAS has developed a broad and systematic search program for dark matter production in LHC collisions. These searches are now entering their prime, with the LHC now colliding protons at the increased 13 TeV centre-of-mass energy and set to deliver much larger datasets than ever before. The results of these searches on the first 13 TeV data, their interpretation, and the design and possible evolution of the search program will be presented.

  4. Searching for the productivity slowdown

    OpenAIRE

    Steiner, Viktor

    1990-01-01

    Searching for the productivity slowdown : some surprising findings from West- German manufacturing / by Gebhard Flaig and Viktor Steiner. - Augsburg, 1990. - 29 S. - (Volkswirtschaftliche Diskussionsreihe ; 45)

  5. Searching and Archiving : Exploring Online Search Behaviors of Researchers

    NARCIS (Netherlands)

    Vyas, Dhaval; de Groot, S.; van der Veer, Gerrit C.; Dainoff, Marvin J.

    2007-01-01

    Searching for relevant peer-reviewed material is an integral part of corporate and academic researchers. Researchers collect huge amount of information over the years and sometimes struggle organizing it. Based on a study with 30 academic researchers, we explore, in combination, different searching

  6. 29 CFR 4050.4 - Diligent search.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Diligent search. 4050.4 Section 4050.4 Labor Regulations... § 4050.4 Diligent search. (a) Search required. A diligent search must be made for each missing... § 4050.6. (b) Diligence. A search is a diligent search only if the search— (1) Begins not more than 6...

  7. The search for the top quark

    International Nuclear Information System (INIS)

    Barbaro-Galtieri, A.

    1989-03-01

    This paper discusses the following topics: top search in the near future, general remarks, top search at HERA, searching for the top quarks at the Z 0 machines, finding the top at Lep II, top search in UA2, top search in UA1, and top search at CDF. 58 refs., 38 figs

  8. Multitasking Web Searching and Implications for Design.

    Science.gov (United States)

    Ozmutlu, Seda; Ozmutlu, H. C.; Spink, Amanda

    2003-01-01

    Findings from a study of users' multitasking searches on Web search engines include: multitasking searches are a noticeable user behavior; multitasking search sessions are longer than regular search sessions in terms of queries per session and duration; both Excite and AlltheWeb.com users search for about three topics per multitasking session and…

  9. Search for interstellar methane

    International Nuclear Information System (INIS)

    Knacke, R.F.; Kim, Y.H.; Noll, K.S.; Geballe, T.R.

    1990-01-01

    Researchers searched for interstellar methane in the spectra of infrared sources embedded in molecular clouds. New observations of several lines of the P and R branches of the nu 3 band of CH4 near 3.3 microns give column densities in the range N less than 1(-2) times 10 to the minus 16th power cm(-2). Resulting abundance ratios are (CH4)/(CO) less than 3.3 times 10 to the minus 2nd power toward GL961 in NGC 2244 and less than 2.4 times 10 to the minus 3rd power toward GL989 in the NGC 2264 molecular cloud. The limits, and those determined in earlier observations of BN in Orion and GL490, suggest that there is little methane in molecular clouds. The result agrees with predictions of chemical models. Exceptions could occur in clouds where oxygen may be depleted, for example by H2O freezing on grains. The present observations probably did not sample such regions

  10. New particle searches

    International Nuclear Information System (INIS)

    Derrick, M.

    1985-01-01

    The Standard Model is a remarkable result of decades of work in particle physics, but it is clearly an incomplete representation of the world. Exploring possibilities beyond the Standard Model is a major preoccupation of both theorists and experimentalists. Despite the many suggestions that are extant about the missing links within the Standard Model as well as extensions beyond it, no hard experimental evidence exists. In particular, in more than five years of experimentation both at PETRA and PEP no new particles have been found that would indicate new physics. Several reasons are possible for these negative results: the particles may be too heavy; the experiments may not be looking in the proper way; the cross sections may be too small or finally the particles may not exist. A continuing PEP program, at high luminosity will ensure that the second and third reason continue to be addressed. The higher energy e + e - storage rings such as TRISTAN and LEP will extend the mass limits. High mass particles can also be produced at the CERN collider and soon with the Tevatron collider. A concise summary of the mass limits from the PETRA experiments has been given in a recent Mark J publication. The results shown provide a convenient yardstick against which to measure future search experiments

  11. Visual Representation Determines Search Difficulty: Explaining Visual Search Asymmetries

    Directory of Open Access Journals (Sweden)

    Neil eBruce

    2011-07-01

    Full Text Available In visual search experiments there exist a variety of experimental paradigms in which a symmetric set of experimental conditions yields asymmetric corresponding task performance. There are a variety of examples of this that currently lack a satisfactory explanation. In this paper, we demonstrate that distinct classes of asymmetries may be explained by virtue of a few simple conditions that are consistent with current thinking surrounding computational modeling of visual search and coding in the primate brain. This includes a detailed look at the role that stimulus familiarity plays in the determination of search performance. Overall, we demonstrate that all of these asymmetries have a common origin, namely, they are a consequence of the encoding that appears in the visual cortex. The analysis associated with these cases yields insight into the problem of visual search in general and predictions of novel search asymmetries.

  12. Zimbabwe Science News: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  13. Agro-Science: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  14. Online Searching at 9600 Baud.

    Science.gov (United States)

    Scott, Ralph Lee; Scott, Nancy Sue Schell

    1991-01-01

    Discusses online searching with the new 9600 baud rate and describes test searches on the BRS, Data-Star, LEXIS, and Dow Jones databases through three packet-switching networks: US Sprint, MEADNET, and TYMNET. Hardware and software are described, data communications equipment standards are discussed, and the impact of higher baud rates on pricing…

  15. IMTU Medical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  16. Mizan Law Review: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. Ethiopian Veterinary Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  18. Health SA Gesondheid: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  19. Malawi Medical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  20. Ethiopian Pharmaceutical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  1. Nigerian Food Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Scientific Medical Journal: Advanced Search

    African Journals Online (AJOL)

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  3. Visual search deficits in amblyopia.

    Science.gov (United States)

    Tsirlin, Inna; Colpa, Linda; Goltz, Herbert C; Wong, Agnes M F

    2018-04-01

    Amblyopia is a neurodevelopmental disorder defined as a reduction in visual acuity that cannot be corrected by optical means. It has been associated with low-level deficits. However, research has demonstrated a link between amblyopia and visual attention deficits in counting, tracking, and identifying objects. Visual search is a useful tool for assessing visual attention but has not been well studied in amblyopia. Here, we assessed the extent of visual search deficits in amblyopia using feature and conjunction search tasks. We compared the performance of participants with amblyopia (n = 10) to those of controls (n = 12) on both feature and conjunction search tasks using Gabor patch stimuli, varying spatial bandwidth and orientation. To account for the low-level deficits inherent in amblyopia, we measured individual contrast and crowding thresholds and monitored eye movements. The display elements were then presented at suprathreshold levels to ensure that visibility was equalized across groups. There was no performance difference between groups on feature search, indicating that our experimental design controlled successfully for low-level amblyopia deficits. In contrast, during conjunction search, median reaction times and reaction time slopes were significantly larger in participants with amblyopia compared with controls. Amblyopia differentially affects performance on conjunction visual search, a more difficult task that requires feature binding and possibly the involvement of higher-level attention processes. Deficits in visual search may affect day-to-day functioning in people with amblyopia.

  4. Next-Gen Search Engines

    Science.gov (United States)

    Gupta, Amardeep

    2005-01-01

    Current search engines--even the constantly surprising Google--seem unable to leap the next big barrier in search: the trillions of bytes of dynamically generated data created by individual web sites around the world, or what some researchers call the "deep web." The challenge now is not information overload, but information overlook.…

  5. Personalization in professional academic search

    NARCIS (Netherlands)

    Verberne, S.; Sappelli, M.; Sørensen, D.R.; Kraaij, W.

    2013-01-01

    In this paper, we investigated how academic search can profit from personalization by incorporating query history and background knowledge in the ranking of the results. We implemented both techniques in a language modelling framework, using the Indri search engine. For our experiments, we used the

  6. Tanzania Medical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  7. Kioo cha Lugha: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  8. Zimbabwe Veterinary Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  9. Nigerian Music Review: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. Semantic Search of Web Services

    Science.gov (United States)

    Hao, Ke

    2013-01-01

    This dissertation addresses semantic search of Web services using natural language processing. We first survey various existing approaches, focusing on the fact that the expensive costs of current semantic annotation frameworks result in limited use of semantic search for large scale applications. We then propose a vector space model based service…

  11. Tanzania Dental Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  12. Continuing Medical Education: Advanced Search

    African Journals Online (AJOL)

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  13. Ghana Mining Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  14. Thought and Practice: Advanced Search

    African Journals Online (AJOL)

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  15. Search Our Site With Google

    African Journals Online (AJOL)

    Search Our Site With Google. Journal Home > Search Our Site With Google. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  16. Law, Democracy & Development: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. African Research Review: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  18. Open Veterinary Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  19. Searches for supersymmetry at CMS

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: F. Giordano on behalf of the CMS Collaboration

    2017-11-15

    Among the most promising prospects for a theory of physics beyond the standard model is supersymmetry. In this talk, the latest results from the CMS experiment at the LHC on searches for supersymmetry produced through strong production and electroweak production channels are presented using 20/fb of data from the 8 TeV LHC run, with particular focus on gluino and stop searches.

  20. Perspectives in Education: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  1. Discovery and Innovation: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  2. Tropical Freshwater Biology: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  3. Nigerian Medical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  4. Tanzania Veterinary Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  5. Nigeria Agricultural Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  6. Evaluating aggregated search using interleaving

    NARCIS (Netherlands)

    Chuklin, A.; Schuth, A.; Hofmann, K.; Serdyukov, P.; de Rijke, M.

    2013-01-01

    A result page of a modern web search engine is often much more complicated than a simple list of "ten blue links." In particular, a search engine may combine results from different sources (e.g., Web, News, and Images), and display these as grouped results to provide a better user experience. Such a

  7. XML and Better Web Searching.

    Science.gov (United States)

    Jackson, Joe; Gilstrap, Donald L.

    1999-01-01

    Addresses the implications of the new Web metalanguage XML for searching on the World Wide Web and considers the future of XML on the Web. Compared to HTML, XML is more concerned with structure of data than documents, and these data structures should prove conducive to precise, context rich searching. (Author/LRW)

  8. Nigerian Dental Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  9. Madagascar Conservation & Development: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  10. ChemSearch Journal: Submissions

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... SCOPE: ChemSearch Journal is a peer-reviewed journal that publishes ... Authors whose papers have been accepted for publication will be notified in writing. ... The literature cited must be discussed to show the relationships between the ...

  11. Nigerian Medical Practitioner: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  12. Gender and Behaviour: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  13. Humanities Review Journal: Advanced Search

    African Journals Online (AJOL)

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  14. Searching for What I Want

    DEFF Research Database (Denmark)

    Liu, Fei; Xiao, Bo Sophia; Lim, Eric

    2016-01-01

    Inefficiencies associated with online information search are amplifying in the current era of big data. Despite growing scholarly interest in studying Internet users’ information search behaviour, there is a paucity of theory-guided investigation in this regard. In this paper, we draw on the theory...

  15. Searching Algorithm Using Bayesian Updates

    Science.gov (United States)

    Caudle, Kyle

    2010-01-01

    In late October 1967, the USS Scorpion was lost at sea, somewhere between the Azores and Norfolk Virginia. Dr. Craven of the U.S. Navy's Special Projects Division is credited with using Bayesian Search Theory to locate the submarine. Bayesian Search Theory is a straightforward and interesting application of Bayes' theorem which involves searching…

  16. Ghana Library Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. Diversity, intent, and aggregated search

    NARCIS (Netherlands)

    de Rijke, M.

    2014-01-01

    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous

  18. Searching for Roots / Pierre Gervasoni

    Index Scriptorium Estoniae

    Gervasoni, Pierre

    1997-01-01

    Uuest heliplaadist "Searching for Roots. Eduard Tubin: Symphonie no 11; Arvo Pärt: Nekrolog-Symphonie no 1; Erkki-Sven Tüür: Searching for Roots - Insula deserta - Zeitraum; Orchestre philharmonique royal de Stockholm, Paavo Järvi (direction)" Virgin Classics 5 45212 2 (distribue par EMI)

  19. Search for unstable photinos

    International Nuclear Information System (INIS)

    Mayer, P.

    1987-04-01

    We have searched in e + e - -annihilation for the photino, the partner of the photon, which is predicted by supersymmetry. Photinos can be pair produced in e + e - annihilation by the exchange of a scalar electron, the partner of the electron. It was assumed that the photino is unstable and decays in a photon and a lighter supersymmetric particle. This second particle leaves the detector unobserved. In the final state one sees then two photons with missing energy and missing momentum. The data were taken with the detector CELLO at the e + e - storage ring PETRA at DESY, Hamburg. The CMS energy was between 38.3 GeV and 46.8 GeV, the total luminosity was 38.3 pb -1 . The liquid argon lead calorimeter of CELLO, the most important part for this analysis, is specialised for the measurement of electromagnetic showers. It has a good space resolution and covers 96% of the solid angle of 4π. We have selected events with 2 photons in the central calorimeter, both with an energy of more than 2 GeV. The high background due to cosmic showers was reduced by accepting only events which were correlated to the time of the e + e - annihilation. Also the direction of the showers had to point to the interaction point. The applied cuts accepted the expected events with a probability P≅0.3. No event was found which was compatible with the production of unstable photinos. One can give limits on the mass of the photino, which depend on the mass of the scalar electron and on the decay path of the photino. In the simplest case, if all photinos decay at the interaction point, photinos with masses below 21 GeV are excluded (with a mass of the scalar electron below 40 GeV). (orig.) [de

  20. Searching for Suicide Information on Web Search Engines in Chinese

    Directory of Open Access Journals (Sweden)

    Yen-Feng Lee

    2017-01-01

    Full Text Available Introduction: Recently, suicide prevention has been an important public health issue. However, with the growing access to information in cyberspace, the harmful information is easily accessible online. To investigate the accessibility of potentially harmful suicide-related information on the internet, we discuss the following issue about searching suicide information on the internet to draw attention to it. Methods: We use five search engines (Google, Yahoo, Bing, Yam, and Sina and four suicide-related search queries (suicide, how to suicide, suicide methods, and want to die in traditional Chinese in April 2016. We classified the first thirty linkages of the search results on each search engine by a psychiatric doctor into suicide prevention, pro-suicide, neutral, unrelated to suicide, or error websites. Results: Among the total 352 unique websites generated, the suicide prevention websites were the most frequent among the search results (37.8%, followed by websites unrelated to suicide (25.9% and neutral websites (23.0%. However, pro-suicide websites were still easily accessible (9.7%. Besides, compared with the USA and China, the search engine originating in Taiwan had the lowest accessibility to pro-suicide information. The results of ANOVA showed a significant difference between the groups, F = 8.772, P < 0.001. Conclusions: This study results suggest a need for further restrictions and regulations of pro-suicide information on the internet. Providing more supportive information online may be an effective plan for suicidal prevention.

  1. Evidence-based Medicine Search: a customizable federated search engine.

    Science.gov (United States)

    Bracke, Paul J; Howse, David K; Keim, Samuel M

    2008-04-01

    This paper reports on the development of a tool by the Arizona Health Sciences Library (AHSL) for searching clinical evidence that can be customized for different user groups. The AHSL provides services to the University of Arizona's (UA's) health sciences programs and to the University Medical Center. Librarians at AHSL collaborated with UA College of Medicine faculty to create an innovative search engine, Evidence-based Medicine (EBM) Search, that provides users with a simple search interface to EBM resources and presents results organized according to an evidence pyramid. EBM Search was developed with a web-based configuration component that allows the tool to be customized for different specialties. Informal and anecdotal feedback from physicians indicates that EBM Search is a useful tool with potential in teaching evidence-based decision making. While formal evaluation is still being planned, a tool such as EBM Search, which can be configured for specific user populations, may help lower barriers to information resources in an academic health sciences center.

  2. Hybrid keyword search auctions

    KAUST Repository

    Goel, Ashish; Munagala, Kamesh

    2009-01-01

    Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer's estimate can use per-impression bids to correct the auctioneer's prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The hybrid

  3. Hybrid keyword search auctions

    KAUST Repository

    Goel, Ashish

    2009-01-01

    Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer\\'s estimate can use per-impression bids to correct the auctioneer\\'s prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The

  4. Spatial search by quantum walk

    International Nuclear Information System (INIS)

    Childs, Andrew M.; Goldstone, Jeffrey

    2004-01-01

    Grover's quantum search algorithm provides a way to speed up combinatorial search, but is not directly applicable to searching a physical database. Nevertheless, Aaronson and Ambainis showed that a database of N items laid out in d spatial dimensions can be searched in time of order √(N) for d>2, and in time of order √(N) poly(log N) for d=2. We consider an alternative search algorithm based on a continuous-time quantum walk on a graph. The case of the complete graph gives the continuous-time search algorithm of Farhi and Gutmann, and other previously known results can be used to show that √(N) speedup can also be achieved on the hypercube. We show that full √(N) speedup can be achieved on a d-dimensional periodic lattice for d>4. In d=4, the quantum walk search algorithm takes time of order √(N) poly(log N), and in d<4, the algorithm does not provide substantial speedup

  5. Classification of Automated Search Traffic

    Science.gov (United States)

    Buehrer, Greg; Stokes, Jack W.; Chellapilla, Kumar; Platt, John C.

    As web search providers seek to improve both relevance and response times, they are challenged by the ever-increasing tax of automated search query traffic. Third party systems interact with search engines for a variety of reasons, such as monitoring a web site’s rank, augmenting online games, or possibly to maliciously alter click-through rates. In this paper, we investigate automated traffic (sometimes referred to as bot traffic) in the query stream of a large search engine provider. We define automated traffic as any search query not generated by a human in real time. We first provide examples of different categories of query logs generated by automated means. We then develop many different features that distinguish between queries generated by people searching for information, and those generated by automated processes. We categorize these features into two classes, either an interpretation of the physical model of human interactions, or as behavioral patterns of automated interactions. Using the these detection features, we next classify the query stream using multiple binary classifiers. In addition, a multiclass classifier is then developed to identify subclasses of both normal and automated traffic. An active learning algorithm is used to suggest which user sessions to label to improve the accuracy of the multiclass classifier, while also seeking to discover new classes of automated traffic. Performance analysis are then provided. Finally, the multiclass classifier is used to predict the subclass distribution for the search query stream.

  6. Searching for Primordial Antimatter

    Science.gov (United States)

    2008-10-01

    Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot

  7. Is searching full text more effective than searching abstracts?

    Science.gov (United States)

    Lin, Jimmy

    2009-02-03

    With the growing availability of full-text articles online, scientists and other consumers of the life sciences literature now have the ability to go beyond searching bibliographic records (title, abstract, metadata) to directly access full-text content. Motivated by this emerging trend, I posed the following question: is searching full text more effective than searching abstracts? This question is answered by comparing text retrieval algorithms on MEDLINE abstracts, full-text articles, and spans (paragraphs) within full-text articles using data from the TREC 2007 genomics track evaluation. Two retrieval models are examined: bm25 and the ranking algorithm implemented in the open-source Lucene search engine. Experiments show that treating an entire article as an indexing unit does not consistently yield higher effectiveness compared to abstract-only search. However, retrieval based on spans, or paragraphs-sized segments of full-text articles, consistently outperforms abstract-only search. Results suggest that highest overall effectiveness may be achieved by combining evidence from spans and full articles. Users searching full text are more likely to find relevant articles than searching only abstracts. This finding affirms the value of full text collections for text retrieval and provides a starting point for future work in exploring algorithms that take advantage of rapidly-growing digital archives. Experimental results also highlight the need to develop distributed text retrieval algorithms, since full-text articles are significantly longer than abstracts and may require the computational resources of multiple machines in a cluster. The MapReduce programming model provides a convenient framework for organizing such computations.

  8. Indirect search for New Physics: complementarity to direct searches

    CERN Document Server

    Mahmoudi, F

    2013-01-01

    We present an overview on the interplay between direct searches for new physics at the LHC and indirect constraints from the flavour sector, with an emphasis on the implications of the recent LHCb results. The complementarity with the Higgs search results will also be addressed. We show the correlation and complementarity between the different sectors in the context of a few specific examples in supersymmetry.

  9. Is searching full text more effective than searching abstracts?

    Directory of Open Access Journals (Sweden)

    Lin Jimmy

    2009-02-01

    Full Text Available Abstract Background With the growing availability of full-text articles online, scientists and other consumers of the life sciences literature now have the ability to go beyond searching bibliographic records (title, abstract, metadata to directly access full-text content. Motivated by this emerging trend, I posed the following question: is searching full text more effective than searching abstracts? This question is answered by comparing text retrieval algorithms on MEDLINE® abstracts, full-text articles, and spans (paragraphs within full-text articles using data from the TREC 2007 genomics track evaluation. Two retrieval models are examined: bm25 and the ranking algorithm implemented in the open-source Lucene search engine. Results Experiments show that treating an entire article as an indexing unit does not consistently yield higher effectiveness compared to abstract-only search. However, retrieval based on spans, or paragraphs-sized segments of full-text articles, consistently outperforms abstract-only search. Results suggest that highest overall effectiveness may be achieved by combining evidence from spans and full articles. Conclusion Users searching full text are more likely to find relevant articles than searching only abstracts. This finding affirms the value of full text collections for text retrieval and provides a starting point for future work in exploring algorithms that take advantage of rapidly-growing digital archives. Experimental results also highlight the need to develop distributed text retrieval algorithms, since full-text articles are significantly longer than abstracts and may require the computational resources of multiple machines in a cluster. The MapReduce programming model provides a convenient framework for organizing such computations.

  10. Searching the ASRS Database Using QUORUM Keyword Search, Phrase Search, Phrase Generation, and Phrase Discovery

    Science.gov (United States)

    McGreevy, Michael W.; Connors, Mary M. (Technical Monitor)

    2001-01-01

    To support Search Requests and Quick Responses at the Aviation Safety Reporting System (ASRS), four new QUORUM methods have been developed: keyword search, phrase search, phrase generation, and phrase discovery. These methods build upon the core QUORUM methods of text analysis, modeling, and relevance-ranking. QUORUM keyword search retrieves ASRS incident narratives that contain one or more user-specified keywords in typical or selected contexts, and ranks the narratives on their relevance to the keywords in context. QUORUM phrase search retrieves narratives that contain one or more user-specified phrases, and ranks the narratives on their relevance to the phrases. QUORUM phrase generation produces a list of phrases from the ASRS database that contain a user-specified word or phrase. QUORUM phrase discovery finds phrases that are related to topics of interest. Phrase generation and phrase discovery are particularly useful for finding query phrases for input to QUORUM phrase search. The presentation of the new QUORUM methods includes: a brief review of the underlying core QUORUM methods; an overview of the new methods; numerous, concrete examples of ASRS database searches using the new methods; discussion of related methods; and, in the appendices, detailed descriptions of the new methods.

  11. Firm Search for External Knowledge

    DEFF Research Database (Denmark)

    Sofka, Wolfgang; Grimpe, Christoph

    2012-01-01

    ignored the institutional context that provides or denies access to external knowledge at the country level. Combining institutional and knowledge search theory, we suggest that the market orientation of the institutional environment and the magnitude of institutional change influence when firms begin......The innovation performance of modern firms is increasingly determined by their ability to search and absorb external knowledge. However, after a certain threshold firms "oversearch" their environment and innovation performance declines. In this paper, we argue that prior literature has largely...... to experience the negative performance effects of oversearch. Based on a comprehensive sample of almost 8,000 firms from ten European countries, we find that institutions matter considerably for firms' search activity. Higher market orientation of institutions increases the effectiveness of firms' search...

  12. A search for megamaser galaxies

    International Nuclear Information System (INIS)

    Norris, R.P.; Gardner, F.F.; Whiteoak, J.B.

    1989-01-01

    The results are reported of a search for OH megamaser emission from a sample of 32 galaxies selected from the IRAS Point Source Catalog on the basis of their infrared properties. For each galaxy (other than those few already observed elsewhere) we have obtained an optical redshift and have searched for both OH and H I emission. The search yielded one new OH megamaser galaxy and H I was detected towards nine objects. We conclude that there are unlikely to be any OH megamasers in the Southern Hemisphere with flux densities comparable to that of Arp 220 (280 mJy), although there may be a population of weaker megamasers. From the statistics of our search we conclude that no special conditions are required to explain the known OH megamasers other than those expected in a cool, dusty, active galaxy. (author)

  13. Four-Dimensional Golden Search

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-25

    The Golden search technique is a method to search a multiple-dimension space to find the minimum. It basically subdivides the possible ranges of parameters until it brackets, to within an arbitrarily small distance, the minimum. It has the advantages that (1) the function to be minimized can be non-linear, (2) it does not require derivatives of the function, (3) the convergence criterion does not depend on the magnitude of the function. Thus, if the function is a goodness of fit parameter such as chi-square, the convergence does not depend on the noise being correctly estimated or the function correctly following the chi-square statistic. And, (4) the convergence criterion does not depend on the shape of the function. Thus, long shallow surfaces can be searched without the problem of premature convergence. As with many methods, the Golden search technique can be confused by surfaces with multiple minima.

  14. Sandia National Laboratories: Search Results

    Science.gov (United States)

    Locations Contact Us Employee Locator Search Menu About Leadership Mission Social Media Community Diversity Social Media Careers View All Jobs Students & Postdocs Benefits & Perks Hiring Process Deployment Centers New Mexico Small Business Assistance Program Sandia's Economic Impact Sandia Science &

  15. The Search for Another Earth

    Indian Academy of Sciences (India)

    IAS Admin

    for our very existence in the universe. Although the search for ... confirmed planet orbiting around the solar-type star 51 Pegasi. ... for planets outside the solar system, termed as extraso- lar planets or ..... another Indian origin astrophysicist.

  16. Levy flights and random searches

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, E P [Laboratorio de Fisica Teorica e Computacional, Departamento de Fisica, Universidade Federal de Pernambuco, Recife-PE, 50670-901 (Brazil); Buldyrev, S V [Department of Physics, Yeshiva University, New York, 10033 (United States); Da Luz, M G E [Departamento de Fisica, Universidade Federal do Parana, Curitiba-PR, 81531-990 (Brazil); Viswanathan, G M [Instituto de Fisica, Universidade Federal de Alagoas, Maceio-AL, 57072-970 (Brazil); Stanley, H E [Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215 (United States)

    2009-10-30

    In this work we discuss some recent contributions to the random search problem. Our analysis includes superdiffusive Levy processes and correlated random walks in several regimes of target site density, mobility and revisitability. We present results in the context of mean-field-like and closed-form average calculations, as well as numerical simulations. We then consider random searches performed in regular lattices and lattices with defects, and we discuss a necessary criterion for distinguishing true superdiffusion from correlated random walk processes. We invoke energy considerations in relation to critical survival states on the edge of extinction, and we analyze the emergence of Levy behavior in deterministic search walks. Finally, we comment on the random search problem in the context of biological foraging.

  17. Search along persistent random walks

    International Nuclear Information System (INIS)

    Friedrich, Benjamin M

    2008-01-01

    Optimal search strategies and their implementations in biological systems are a subject of active research. Here we study a search problem which is motivated by the hunt of sperm cells for the egg. We ask for the probability for an active swimmer to find a target under the condition that the swimmer starts at a certain distance from the target. We find that success probability is maximal for a certain level of fluctuations characterized by the persistence length of the swimming path of the swimmer. We derive a scaling law for the optimal persistence length as a function of the initial target distance and search time by mapping the search on a polymer physics problem

  18. Adventures in search of auroras

    Science.gov (United States)

    Forsyth, Colin

    2016-09-01

    In her book Aurora: In Search of the Northern Lights, Melanie Windridge describes travelling around the Arctic Circle on a quest to see the biggest and best auroral displays and to understand the physics that drives them.

  19. Searches for Supersymmetry in ATLAS

    CERN Document Server

    Cervelli, Alberto; The ATLAS collaboration

    2017-01-01

    After the discovery of the Higgs boson in ATLAS first run of data taking, and due to the lack of observation of new physics, searches for new particles such as Supersymmetric states are one of the main area of interest for the general purpose detectors operating at LHC. In this talk we will present a review of the searches for Supersymmetric particles, performed by the ATLAS experiment

  20. SUSY searches at D0

    International Nuclear Information System (INIS)

    Sawyer, L.; Texas Univ., Arlington, TX

    1993-06-01

    Searches for evidence of supersymmetric particles, and other phenomena beyond the Standard Model, are well underway with the D0 detector at the Tevatron. The D0 detector has good central tracking, excellent energy and missing E T resolution, hermetic calorimetry, and wide muon coverage. Preliminary results from searches for gluino/squark production and first generation leptoquark production are presented, based on a small fraction of the data taken to date

  1. Housing Search and Consumption Adjustment,

    Science.gov (United States)

    1980-04-01

    bility have appeared in the literature (Speare et al., 1975; Hanushek and Quigley, 1978; Brummell, 1979). Although differing on specifics, these...divide into two types: formal models of the decision to move (Speare et al., 1975; Hanushek and Quigley, 1978) that recognize housing search as a trans...effort expended in searching for a new unit (Abt, 1978; Hanushek and Quigley, 1978; Cronin, 1978). Geographers refer to residential stress and resistance

  2. Content Based Searching for INIS

    International Nuclear Information System (INIS)

    Jain, V.; Jain, R.K.

    2016-01-01

    Full text: Whatever a user wants is available on the internet, but to retrieve the information efficiently, a multilingual and most-relevant document search engine is a must. Most current search engines are word based or pattern based. They do not consider the meaning of the query posed to them; purely based on the keywords of the query; no support of multilingual query and and dismissal of nonrelevant results. Current information-retrieval techniques either rely on an encoding process, using a certain perspective or classification scheme, to describe a given item, or perform a full-text analysis, searching for user-specified words. Neither case guarantees content matching because an encoded description might reflect only part of the content and the mere occurrence of a word does not necessarily reflect the document’s content. For general documents, there doesn’t yet seem to be a much better option than lazy full-text analysis, by manually going through those endless results pages. In contrast to this, new search engine should extract the meaning of the query and then perform the search based on this extracted meaning. New search engine should also employ Interlingua based machine translation technology to present information in the language of choice of the user. (author

  3. Visualization of Pulsar Search Data

    Science.gov (United States)

    Foster, R. S.; Wolszczan, A.

    1993-05-01

    The search for periodic signals from rotating neutron stars or pulsars has been a computationally taxing problem to astronomers for more than twenty-five years. Over this time interval, increases in computational capability have allowed ever more sensitive searches, covering a larger parameter space. The volume of input data and the general presence of radio frequency interference typically produce numerous spurious signals. Visualization of the search output and enhanced real-time processing of significant candidate events allow the pulsar searcher to optimally processes and search for new radio pulsars. The pulsar search algorithm and visualization system presented in this paper currently runs on serial RISC based workstations, a traditional vector based super computer, and a massively parallel computer. A description of the serial software algorithm and its modifications for massively parallel computing are describe. The results of four successive searches for millisecond period radio pulsars using the Arecibo telescope at 430 MHz have resulted in the successful detection of new long-period and millisecond period radio pulsars.

  4. Atypical feeding behavior of Long-tailed Ducks in the wake of a commercial fishing boat while clamming

    Science.gov (United States)

    Perry, Matthew; Osenton, Peter C.; White, Timothy P.

    2017-01-01

    A foraging group of Clangula hyemalis (Long-tailed Duck) was observed on 10 February 2010 diving behind a commercial boat that was clamming near Monomoy Island, Nantucket Sound, MA. We used a shotgun to collect 9 of the ducks, and our analyses of gizzard and gullet (esophagus and proventriculus) revealed 37 food items in the gizzard and 16 in the gullet. Mollusca were the dominant food in the gizzard (49%), whereas Crustacea were dominant in the gullet (57%). Crustacea were the second most important food in the gizzard (38%), whereas Mollusca were the second most important food in the gullet (31%). Relatively high volumes of the Amphipoda Caprella sp. (skeleton shrimp) and the Decopoda Crangon septemspinosa (Sand Shrimp) were recorded in the gullet and gizzard. Ensis directus (Atlantic Jackknife Clam) formed the greatest volume of Mollusca in the gizzard (15%) and in the gullet (15%). Long-tailed Ducks had fed on this Bivalvia and several other species of Mollusca that had no shell or broken shell when consumed. Many of the food organisms were apparently dislodged and some damaged by the clamming operation creating an opportunistic feeding strategy for the Long-tailed Ducks.

  5. Randomized Search Strategies With Imperfect Sensors

    National Research Council Canada - National Science Library

    Gage, Douglas W

    1993-01-01

    .... An important class of coverage applications are those that involve a search, in which a number of searching elements move about within a prescribed search area in order to find one or more target...

  6. Search Path Evaluation Incorporating Object Placement Structure

    National Research Council Canada - National Science Library

    Baylog, John G; Wettergren, Thomas A

    2007-01-01

    This report describes a computationally robust approach to search path performance evaluation where the objects of search interest exhibit structure in the way in which they occur within the search space...

  7. Searches for new particles at LEP

    International Nuclear Information System (INIS)

    Jimack, M.P.

    1991-01-01

    A review of searches for new particles at LEP is presented, including top b' quark searches; L ± , L 0 searches; searches for SUSY particles, the minimal standard mode Higgs boson; search for the h 0 (A 0 ); search for the H ± ; composite systems. No evidence for new physics has been seen, and mass limits are placed on new quarks and leptons, supersymmetric particles, Higgs particles and composite objects. (R.P.) 27 refs., 14 figs., 7 tabs

  8. Teknik Perangkingan Meta-search Engine

    OpenAIRE

    Puspitaningrum, Diyah

    2014-01-01

    Meta-search engine mengorganisasikan penyatuan hasil dari berbagai search engine dengan tujuan untuk meningkatkan presisi hasil pencarian dokumen web. Pada survei teknik perangkingan meta-search engine ini akan didiskusikan isu-isu pra-pemrosesan, rangking, dan berbagai teknik penggabungan hasil pencarian dari search engine yang berbeda-beda (multi-kombinasi). Isu-isu implementasi penggabungan 2 search engine dan 3 search engine juga menjadi sorotan. Pada makalah ini juga dibahas arahan penel...

  9. Personalizing Web Search based on User Profile

    OpenAIRE

    Utage, Sharyu; Ahire, Vijaya

    2016-01-01

    Web Search engine is most widely used for information retrieval from World Wide Web. These Web Search engines help user to find most useful information. When different users Searches for same information, search engine provide same result without understanding who is submitted that query. Personalized web search it is search technique for proving useful result. This paper models preference of users as hierarchical user profiles. a framework is proposed called UPS. It generalizes profile and m...

  10. New particle searches at CDF

    International Nuclear Information System (INIS)

    Nodulman, L.J.

    1995-09-01

    One of the fundamental roles of a general purpose detector exploring, by means of increasing luminosity, higher and higher mass reach, is to search for new particles and exotic phenomena. This is a continuing effort for the CDF collaboration, and will report on several searches using about 20 pb -1 from the 1992/93 run labelled open-quotes run 1aclose quotes and ∼50 of the 90 pb -1 so far from the current open-quotes run 1b.close quotes These are mostly preliminary analyses, typically using a total of 70 pb -1 . Our limits on SUSY using missing E T with jets as well as three leptons are discussed elsewhere; results from the D0 collaboration are similar. I will discuss searches for additional vector bosons Z' and W', second generation scalar leptoquarks, as well as a broad search for objects decaying into jet pairs, including b-tagged jet pairs. I will also describe two events which do not fit in comfortably with either the standard model or a phenomenologically motivated search

  11. Cover times of random searches

    Science.gov (United States)

    Chupeau, Marie; Bénichou, Olivier; Voituriez, Raphaël

    2015-10-01

    How long must one undertake a random search to visit all sites of a given domain? This time, known as the cover time, is a key observable to quantify the efficiency of exhaustive searches, which require a complete exploration of an area and not only the discovery of a single target. Examples range from immune-system cells chasing pathogens to animals harvesting resources, from robotic exploration for cleaning or demining to the task of improving search algorithms. Despite its broad relevance, the cover time has remained elusive and so far explicit results have been scarce and mostly limited to regular random walks. Here we determine the full distribution of the cover time for a broad range of random search processes, including Lévy strategies, intermittent strategies, persistent random walks and random walks on complex networks, and reveal its universal features. We show that for all these examples the mean cover time can be minimized, and that the corresponding optimal strategies also minimize the mean search time for a single target, unambiguously pointing towards their robustness.

  12. Correlations in the Grover search

    International Nuclear Information System (INIS)

    Cui Jian; Fan Heng

    2010-01-01

    The Grover search is a well-known quantum algorithm that outperforms any classical search algorithm. It is known that quantum correlations such as entanglement are responsible for the power of some quantum information protocols. But entanglement is not the only kind of quantum correlations. Other quantum correlations such as quantum discord are also useful to capture some important properties of the nonclassical correlation. Also there is no well-accepted and clear distinction between quantum correlations and classical correlations. In this paper, we systematically investigate several kinds of correlations including both quantum and classical in the whole process of the Grover search algorithm. These correlations are the concurrence, entanglement of formation, quantum discord, classical correlation and mutual information. The behaviors of quantum discord, classical correlation and mutual information are almost the same while the concurrence is different in the qubit-qubit case. For the qubit partition 1: n case, the behaviors of all correlations are qualitative the same. When the search is over, all kinds of correlations are zero, we argue that this is necessary for the final step in the search.

  13. Optimal Fungal Space Searching Algorithms.

    Science.gov (United States)

    Asenova, Elitsa; Lin, Hsin-Yu; Fu, Eileen; Nicolau, Dan V; Nicolau, Dan V

    2016-10-01

    Previous experiments have shown that fungi use an efficient natural algorithm for searching the space available for their growth in micro-confined networks, e.g., mazes. This natural "master" algorithm, which comprises two "slave" sub-algorithms, i.e., collision-induced branching and directional memory, has been shown to be more efficient than alternatives, with one, or the other, or both sub-algorithms turned off. In contrast, the present contribution compares the performance of the fungal natural algorithm against several standard artificial homologues. It was found that the space-searching fungal algorithm consistently outperforms uninformed algorithms, such as Depth-First-Search (DFS). Furthermore, while the natural algorithm is inferior to informed ones, such as A*, this under-performance does not importantly increase with the increase of the size of the maze. These findings suggest that a systematic effort of harvesting the natural space searching algorithms used by microorganisms is warranted and possibly overdue. These natural algorithms, if efficient, can be reverse-engineered for graph and tree search strategies.

  14. Guided search for triple conjunctions.

    Science.gov (United States)

    Nordfang, Maria; Wolfe, Jeremy M

    2014-08-01

    A key tenet of feature integration theory and of related theories such as guided search (GS) is that the binding of basic features requires attention. This would seem to predict that conjunctions of features of objects that have not been attended should not influence search. However, Found (1998) reported that an irrelevant feature (size) improved the efficiency of search for a Color × Orientation conjunction if it was correlated with the other two features across the display, as compared to the case in which size was not correlated with color and orientation features. We examined this issue with somewhat different stimuli. We used triple conjunctions of color, orientation, and shape (e.g., search for a red, vertical, oval-shaped item). This allowed us to manipulate the number of features that each distractor shared with the target (sharing) and it allowed us to vary the total number of distractor types (and, thus, the number of groups of identical items: grouping). We found that these triple conjunction searches were generally very efficient--producing very shallow Reaction Time × Set Size slopes, consistent with strong guidance by basic features. Nevertheless, both of the variables, sharing and grouping, modulated performance. These influences were not predicted by previous accounts of GS; however, both can be accommodated in a GS framework. Alternatively, it is possible, though not necessary, to see these effects as evidence for "preattentive binding" of conjunctions.

  15. High-speed data search

    Science.gov (United States)

    Driscoll, James N.

    1994-01-01

    The high-speed data search system developed for KSC incorporates existing and emerging information retrieval technology to help a user intelligently and rapidly locate information found in large textual databases. This technology includes: natural language input; statistical ranking of retrieved information; an artificial intelligence concept called semantics, where 'surface level' knowledge found in text is used to improve the ranking of retrieved information; and relevance feedback, where user judgements about viewed information are used to automatically modify the search for further information. Semantics and relevance feedback are features of the system which are not available commercially. The system further demonstrates focus on paragraphs of information to decide relevance; and it can be used (without modification) to intelligently search all kinds of document collections, such as collections of legal documents medical documents, news stories, patents, and so forth. The purpose of this paper is to demonstrate the usefulness of statistical ranking, our semantic improvement, and relevance feedback.

  16. Quantum walks and search algorithms

    CERN Document Server

    Portugal, Renato

    2013-01-01

    This book addresses an interesting area of quantum computation called quantum walks, which play an important role in building quantum algorithms, in particular search algorithms. Quantum walks are the quantum analogue of classical random walks. It is known that quantum computers have great power for searching unsorted databases. This power extends to many kinds of searches, particularly to the problem of finding a specific location in a spatial layout, which can be modeled by a graph. The goal is to find a specific node knowing that the particle uses the edges to jump from one node to the next. This book is self-contained with main topics that include: Grover's algorithm, describing its geometrical interpretation and evolution by means of the spectral decomposition of the evolution operater Analytical solutions of quantum walks on important graphs like line, cycles, two-dimensional lattices, and hypercubes using Fourier transforms Quantum walks on generic graphs, describing methods to calculate the limiting d...

  17. Organizational search and market orientation

    DEFF Research Database (Denmark)

    Sørensen, Hans Eibe; Stieglitz, Nils

    2008-01-01

      Market orientation has evolved into a key construct in the marketing and strategy literature. While much progress has been made in empirical research, the concept lacks a coherent theoretical foundation. Essentially, much prior research has pointed to the role of market-sensing capabilities...... to explain performance differentials among firms (Day, 1994). We open up the black box of market-sensing capabilities by treating the issue of choosing marketing attributes of products as a problem of organizational search. Despite much robust research on organizational search in the strategy......, with their effectiveness depending on organizational and environmental factors. We provide an elaborate outline of the multidimensional aspect of firms' responsive and proactive search processes. First, we highlight the role of organizational aspiration-levels for market orientation. We then investigate the mechanisms...

  18. Evaluation Framework for Search Instruments

    International Nuclear Information System (INIS)

    Warren, Glen A.; Smith, Leon E.; Cooper, Matt W.; Kaye, William R.

    2005-01-01

    A framework for quantitatively evaluating current and proposed gamma-ray search instrument designs has been developed. The framework is designed to generate a large library of ''virtual neighborhoods'' that can be used to test and evaluate nearly any gamma-ray sensor type. Calculating nuisance-source emissions and combining various sources to create a large number of random virtual scenes places a significant computational burden on the development of the framework. To reduce this burden, a number of radiation transport simplifications have been made which maintain the essential physics ingredients for the quantitative assessment of search instruments while significantly reducing computational times. The various components of the framework, from the simulation and benchmarking of nuisance source emissions to the computational engine for generating the gigabytes of simulated search scenes, are discussed

  19. Refining search terms for nanotechnology

    International Nuclear Information System (INIS)

    Porter, Alan L.; Youtie, Jan; Shapira, Philip; Schoeneck, David J.

    2008-01-01

    The ability to delineate the boundaries of an emerging technology is central to obtaining an understanding of the technology's research paths and commercialization prospects. Nowhere is this more relevant than in the case of nanotechnology (hereafter identified as 'nano') given its current rapid growth and multidisciplinary nature. (Under the rubric of nanotechnology, we also include nanoscience and nanoengineering.) Past efforts have utilized several strategies, including simple term search for the prefix nano, complex lexical and citation-based approaches, and bootstrapping techniques. This research introduces a modularized Boolean approach to defining nanotechnology which has been applied to several research and patenting databases. We explain our approach to downloading and cleaning data, and report initial results. Comparisons of this approach with other nanotechnology search formulations are presented. Implications for search strategy development and profiling of the nanotechnology field are discussed

  20. Dark Matter searches at ATLAS

    CERN Document Server

    Cortes-Gonzalez, Arely; The ATLAS collaboration

    2016-01-01

    If Dark Matter interacts weakly with the Standard Model it can be produced at the LHC. It can be identified via initial state radiation (ISR) of the incoming partons, leaving a signature in the detector of the ISR particle (jet, photon, Z or W) recoiling off of the invisible Dark Matter particles, resulting in a large momentum imbalance. Many signatures of large missing transverse momentum recoiling against jets, photons, heavy-flavor quarks, weak gauge bosons or Higgs bosons provide an interesting channel for Dark Matter searches. These LHC searches complement those from (in)direct detection experiments. Results of these searches with the ATLAS experiment, in both effective field theory and simplified models with pair WIMP production are discussed. Both 8TeV and 13TeV pp collision data has been used in these results.

  1. Refining search terms for nanotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Alan L. [Georgia Institute of Technology (United States); Youtie, Jan [Georgia Institute of Technology, Enterprise Innovation Institute (United States)], E-mail: jan.youtie@innovate.gatech.edu; Shapira, Philip [Georgia Institute of Technology (United States); Schoeneck, David J. [Search Technology, Inc. (United States)

    2008-05-15

    The ability to delineate the boundaries of an emerging technology is central to obtaining an understanding of the technology's research paths and commercialization prospects. Nowhere is this more relevant than in the case of nanotechnology (hereafter identified as 'nano') given its current rapid growth and multidisciplinary nature. (Under the rubric of nanotechnology, we also include nanoscience and nanoengineering.) Past efforts have utilized several strategies, including simple term search for the prefix nano, complex lexical and citation-based approaches, and bootstrapping techniques. This research introduces a modularized Boolean approach to defining nanotechnology which has been applied to several research and patenting databases. We explain our approach to downloading and cleaning data, and report initial results. Comparisons of this approach with other nanotechnology search formulations are presented. Implications for search strategy development and profiling of the nanotechnology field are discussed.

  2. Visual search of Mooney faces

    Directory of Open Access Journals (Sweden)

    Jessica Emeline Goold

    2016-02-01

    Full Text Available Faces spontaneously capture attention. However, which special attributes of a face underlie this effect are unclear. To address this question, we investigate how gist information, specific visual properties and differing amounts of experience with faces affect the time required to detect a face. Three visual search experiments were conducted investigating the rapidness of human observers to detect Mooney face images. Mooney images are two-toned, ambiguous images. They were used in order to have stimuli that maintain gist information but limit low-level image properties. Results from the experiments show: 1 although upright Mooney faces were searched inefficiently, they were detected more rapidly than inverted Mooney face targets, demonstrating the important role of gist information in guiding attention towards a face. 2 Several specific Mooney face identities were searched efficiently while others were not, suggesting the involvement of specific visual properties in face detection. 3 By providing participants with unambiguous gray-scale versions of the Mooney face targets prior to the visual search task, the targets were detected significantly more efficiently, suggesting that prior experience with Mooney faces improves the ability to extract gist information for rapid face detection. However, a week of training with Mooney face categorization did not lead to even more efficient visual search of Mooney face targets. In summary, these results reveal that specific local image properties cannot account for how faces capture attention. On the other hand, gist information alone cannot account for how faces capture attention either. Prior experience facilitates the effect of gist on visual search of faces, making faces a special object category for guiding attention.

  3. In Search of a Hero, in Search of Self

    Science.gov (United States)

    Jolley, Susan Arpajian

    2007-01-01

    In this article, the author vitalizes her British literature course by asking seniors to investigate, through an I-Search paper, the concept of heroism. Students research a historic or contemporary individual, drawing on their understanding of heroic literary figures previously studied, and interview family, community members, and others connected…

  4. Evaluating search effectiveness of some selected search engines ...

    African Journals Online (AJOL)

    With advancement in technology, many individuals are getting familiar with the internet a lot of users seek for information on the World Wide Web (WWW) using variety of search engines. This research work evaluates the retrieval effectiveness of Google, Yahoo, Bing, AOL and Baidu. Precision, relative recall and response ...

  5. SUSY searches at the Tevatron

    International Nuclear Information System (INIS)

    Chertok, Maxwell

    1998-01-01

    CDF and D0 have performed searches for Supersymmetry with data collected at √s = 1.8 TeV during the years 1992-95. These searches are based on detector signatures: events with appreciable missing transverse energy plus jets with or without dileptons can signal squark and gluino production; the spectacular signature of trilepton events can result from the production of charginos and neutralinos; and the inclusion of R parity violation can produce events with like-sign dileptons and no missing transverse energy. Results from these analyses are presented

  6. Search-User Interface Design

    CERN Document Server

    Wilson, Max

    2011-01-01

    Search User Interfaces (SUIs) represent the gateway between people who have a task to complete, and the repositories of information and data stored around the world. Not surprisingly, therefore, there are many communities who have a vested interest in the way SUIs are designed. There are people who study how humans search for information, and people who study how humans use computers. There are people who study good user interface design, and people who design aesthetically pleasing user interfaces. There are also people who curate and manage valuable information resources, and people who desi

  7. Goiania 1987: searching for radiation

    International Nuclear Information System (INIS)

    Clarke Binns, D.A.

    1998-01-01

    The founding of the Searching for Radiation Group following the radiation accident in Goiania, Brazil, in 1987, is described. Particulars on the equipment and detector used, the number of people monitored, the techniques used to gather information on the probable date of the accident, about possibly contaminated places and people are provided and communicating with the general public is addressed. The discussion is divided into three main parts: 1) how the Searching for Radiation Group was formed; 2) the participation of the state Health Secretariat and the street children in the Group and 3) the lessons learned. (author)

  8. Fault-ignorant quantum search

    International Nuclear Information System (INIS)

    Vrana, Péter; Reeb, David; Reitzner, Daniel; Wolf, Michael M

    2014-01-01

    We investigate the problem of quantum searching on a noisy quantum computer. Taking a fault-ignorant approach, we analyze quantum algorithms that solve the task for various different noise strengths, which are possibly unknown beforehand. We prove lower bounds on the runtime of such algorithms and thereby find that the quadratic speedup is necessarily lost (in our noise models). However, for low but constant noise levels the algorithms we provide (based on Grover's algorithm) still outperform the best noiseless classical search algorithm. (paper)

  9. Recent results on SUSY searches from CMS

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    The latest results on searches for Supersymmetry from CMS are reviewed. We present searches for direct stop production, searches in final states with four W bosons and multiple b-quarks, and searches for R-Parity violating SUSY. The results use up to 20/fb of data from the 8 TeV LHC run of 2012.

  10. Search engines that learn from their users

    NARCIS (Netherlands)

    Schuth, A.G.

    2016-01-01

    More than half the world’s population uses web search engines, resulting in over half a billion search queries every single day. For many people web search engines are among the first resources they go to when a question arises. Moreover, search engines have for many become the most trusted route to

  11. Improvement Of Search Process In Electronic Catalogues

    Directory of Open Access Journals (Sweden)

    Titas Savickas

    2014-05-01

    Full Text Available The paper presents investigation on search in electronic catalogues. The chosen problem domain is the search system in the electronic catalogue of Lithuanian Academic Libraries. The catalogue uses ALEPH system with MARC21 bibliographic format. The article presents analysis of problems pertaining to the current search engine and user expectations related to the search system of the electronic catalogue of academic libraries. Subsequent to analysis, the research paper presents the architecture for a semantic search system in the electronic catalogue that uses search process designed to improve search results for users.

  12. Optimal Labour Taxation and Search

    NARCIS (Netherlands)

    Boone, J.; Bovenberg, A.L.

    2000-01-01

    This paper explores the optimal role of the tax system in alleviating labour-market imperfections, raising revenue, and correcting the income distribution. For this purpose, the standard search model of the labour market is extended by introducing non-linear vacancy costs due to scarce

  13. Search Engine For Ebook Portal

    Directory of Open Access Journals (Sweden)

    Prashant Kanade

    2017-05-01

    Full Text Available The purpose of this paper is to establish the textual analytics involved in developing a search engine for an ebook portal. We have extracted our dataset from Project Gutenberg using a robot harvester. Textual Analytics is used for efficient search retrieval. The entire dataset is represented using Vector Space Model where each document is a vector in the vector space. Further for computational purposes we represent our dataset in the form of a Term Frequency- Inverse Document Frequency tf-idf matrix. The first step involves obtaining the most coherent sequence of words of the search query entered. The entered query is processed using Front End algorithms this includes-Spell Checker Text Segmentation and Language Modeling. Back End processing includes Similarity Modeling Clustering Indexing and Retrieval. The relationship between documents and words is established using cosine similarity measured between the documents and words in Vector Space. Clustering performed is used to suggest books that are similar to the search query entered by the user. Lastly the Lucene Based Elasticsearch engine is used for indexing on the documents. This allows faster retrieval of data. Elasticsearch returns a dictionary and creates a tf-idf matrix. The processed query is compared with the dictionary obtained and tf-idf matrix is used to calculate the score for each match to give most relevant result.

  14. Search for leptoquarks at CMS

    CERN Document Server

    Morse, David Michael

    2018-01-01

    A summary of the current experimental searches for leptoquarks with the CMS detector at the CERN LHC is presented, along with updates of new results from analyses performed using the full 2016 proton-proton dataset, corresponding to 35.9 fb$^{-1}$.

  15. Intelligent Search on XML Data

    NARCIS (Netherlands)

    Blanken, Henk; Grabs, T.; Schek, H-J.; Schenkel, R.; Weikum, G.; Unknown, [Unknown

    2003-01-01

    Recently, we have seen a steep increase in the popularity and adoption of XML, in areas such as traditional databases, e-business, the scientific environment, and on the web. Querying XML documents and data efficiently is a challenging issue; this book approaches search on XML data by combining

  16. The search for dark matter

    International Nuclear Information System (INIS)

    Smith, Nigel; Spooner, Neil

    2000-01-01

    Experiments housed deep underground are searching for new particles that could simultaneously solve one of the biggest mysteries in astrophysics and reveal what lies beyond the Standard Model of particle physics. Physicists are very particular about balancing budgets. Energy, charge and momentum all have to be conserved and often money as well. Astronomers were therefore surprised and disturbed to learn in the 1930s that our own Milky Way galaxy behaved as if it contained more matter than could be seen with telescopes. This puzzling non-luminous matter became known as ''dark matter'' and we now know that over 90% of the matter in the entire universe is dark. In later decades the search for this dark matter shifted from the heavens to the Earth. In fact, the search for dark matter went underground. Today there are experiments searching for dark matter hundreds and thousands of metres below ground in mines, road tunnels and other subterranean locations. These experiments are becoming more sensitive every year and are beginning to test various new models and theories in particle physics and cosmology. (UK)

  17. Higgs particle searches at LEP

    International Nuclear Information System (INIS)

    Martin, J.P.

    1996-01-01

    Results on searches for the Higgs particle performed by the four LEP experiments are received in the framework of the Standard Model, Two Doublet Model, and Minimal Supersymmetric Model. The combined mass lower limit for the standard Higgs boson is 66 GeV/c 2 at 95 % CL for a statistics of 14.6 Million hadronic Z decays. (authors)

  18. Indirect searches for dark matter

    Indian Academy of Sciences (India)

    The current status of indirect searches for dark matter has been reviewed in a schematic way here. The main relevant experimental results of the recent years have been listed and the excitements and disappointments that their phenomenological interpretations in terms of almost-standard annihilating dark matter have ...

  19. Animal Research International: Advanced Search

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH ... Animal Research International: Advanced Search ... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ... Journal of Biomedical Research, African Journal of Biotechnology, African Journal of Chemical Education ...

  20. SBA - Dynamic Small Business Search

    Science.gov (United States)

    Mobile View Print Exit Help DSBS Quick Market Search TM OnLine DSBS Welcome to the Dynamic Small Business relating to 8(a) Business Development, HUBZone or Small Disadvantaged Business status. The SBA strongly recommends that contracting officers diligently review a bidder's small business self-certification before

  1. Oromia Law Journal: Advanced Search

    African Journals Online (AJOL)

    ... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., archive ((journal OR conference) NOT theses); Search for an exact phrase by putting it in quotes; e.g., "open access publishing"; Exclude a word by prefixing it with - or NOT; e.g. online -politics or online NOT politics ...

  2. Haramaya Law Review: Advanced Search

    African Journals Online (AJOL)

    ... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., archive ((journal OR conference) NOT theses); Search for an exact phrase by putting it in quotes; e.g., "open access publishing"; Exclude a word by prefixing it with - or NOT; e.g. online -politics or online NOT politics ...

  3. Zebra: searching for rare diseases

    DEFF Research Database (Denmark)

    Dragusin, Radu; Petcu, Paula; Lioma, Christina

    2012-01-01

    disease diagnostic hypotheses in the domain of medical IR. In this work, we build upon an existing vertical medical search engine, Zebra, that is focused on rare disease diagnosis. In previous work, Zebra has been evaluated using real-life medical cases of rare and difficult diseases, and has been found...

  4. NBIC: Search Ballast Report Database

    Science.gov (United States)

    Smithsonian Environmental Research Center Logo US Coast Guard Logo Submit BW Report | Search NBIC Database developed an online database that can be queried through our website. Data are accessible for all coastal Lakes, have been incorporated into the NBIC database as of August 2004. Information on data availability

  5. The Search for Another Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 7. The Search for ... https://www.ias.ac.in/article/fulltext/reso/021/07/0641-0652 ... In the first part of this article, we shall describethe different astronomical methods through whichthe extrasolar planets of various kinds are discovered.In the second ...

  6. Fast business process similarity search

    NARCIS (Netherlands)

    Yan, Z.; Dijkman, R.M.; Grefen, P.W.P.J.

    2012-01-01

    Nowadays, it is common for organizations to maintain collections of hundreds or even thousands of business processes. Techniques exist to search through such a collection, for business process models that are similar to a given query model. However, those techniques compare the query model to each

  7. Information Diversity in Web Search

    Science.gov (United States)

    Liu, Jiahui

    2009-01-01

    The web is a rich and diverse information source with incredible amounts of information about all kinds of subjects in various forms. This information source affords great opportunity to build systems that support users in their work and everyday lives. To help users explore information on the web, web search systems should find information that…

  8. Single photon searches at PEP

    Energy Technology Data Exchange (ETDEWEB)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented.

  9. Single photon searches at PEP

    International Nuclear Information System (INIS)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented

  10. Discovery and Innovation: Advanced Search

    African Journals Online (AJOL)

    ... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., archive ((journal OR conference) NOT theses); Search for an exact phrase by putting it in quotes; e.g., "open access publishing"; Exclude a word by prefixing it with - or NOT; e.g. online -politics or online NOT politics ...

  11. Analytical Methods in Search Theory

    Science.gov (United States)

    1979-11-01

    X, t ) ,I pick g(x,t;E), *(x,tjc) and find the b necessary to satisfy the search equation. SOLUTION: This is an audience participation problem. It...Cnstotiaticon G11trant,’ ’I pp 2110 Path lestegsls,’ to pp., Jun IBM Iltetteol Pepsi pp., Ott 1313 (Tt o besubmitoet lot pubtinatteon l t Messino, Daidit

  12. Search for extraterrestrial intelligence (SETI)

    International Nuclear Information System (INIS)

    Morrison, P.; Billingham, J.; Wolfe, J.

    1977-01-01

    Findings are presented of a series of workshops on the existence of extraterrestrial intelligent life and ways in which extraterrestrial intelligence might be detected. The coverage includes the cosmic and cultural evolutions, search strategies, detection of other planetary systems, alternate methods of communication, and radio frequency interference. 17 references

  13. The Search for Cosmological Antimatter

    Science.gov (United States)

    Streitmatter, Robert E.

    2004-01-01

    For more than 40 years, experimentalists have searched in the cosmic radiation for evidence of antimatter which may have been created in the early Universe. The experimental evidence for cosmologically significant amounts of antimatter in the Universe is reviewed. There is no compelling evidence, either theoretical of experimental. However, the possibility is not completely ruled out.

  14. African Studies Monographs: Advanced Search

    African Journals Online (AJOL)

    ... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., archive ((journal OR conference) NOT theses); Search for an exact phrase by putting it in quotes; e.g., "open access publishing"; Exclude a word by prefixing it with - or NOT; e.g. online -politics or online NOT politics ...

  15. New generation of the multimedia search engines

    Science.gov (United States)

    Mijes Cruz, Mario Humberto; Soto Aldaco, Andrea; Maldonado Cano, Luis Alejandro; López Rodríguez, Mario; Rodríguez Vázqueza, Manuel Antonio; Amaya Reyes, Laura Mariel; Cano Martínez, Elizabeth; Pérez Rosas, Osvaldo Gerardo; Rodríguez Espejo, Luis; Flores Secundino, Jesús Abimelek; Rivera Martínez, José Luis; García Vázquez, Mireya Saraí; Zamudio Fuentes, Luis Miguel; Sánchez Valenzuela, Juan Carlos; Montoya Obeso, Abraham; Ramírez Acosta, Alejandro Álvaro

    2016-09-01

    Current search engines are based upon search methods that involve the combination of words (text-based search); which has been efficient until now. However, the Internet's growing demand indicates that there's more diversity on it with each passing day. Text-based searches are becoming limited, as most of the information on the Internet can be found in different types of content denominated multimedia content (images, audio files, video files). Indeed, what needs to be improved in current search engines is: search content, and precision; as well as an accurate display of expected search results by the user. Any search can be more precise if it uses more text parameters, but it doesn't help improve the content or speed of the search itself. One solution is to improve them through the characterization of the content for the search in multimedia files. In this article, an analysis of the new generation multimedia search engines is presented, focusing the needs according to new technologies. Multimedia content has become a central part of the flow of information in our daily life. This reflects the necessity of having multimedia search engines, as well as knowing the real tasks that it must comply. Through this analysis, it is shown that there are not many search engines that can perform content searches. The area of research of multimedia search engines of new generation is a multidisciplinary area that's in constant growth, generating tools that satisfy the different needs of new generation systems.

  16. SEARCH

    International Development Research Centre (IDRC) Digital Library (Canada)

    Chaitali Sinha

    Como en el caso de la salud, cuya competencia va más allá del Ministerio ... en cuenta que un desarrollo que vaya más allá de una conciencia básica .... Las presentaciones electrónicas se deberán enviar en formato PDF o Microsoft Word.

  17. I-SG : Interactive Search Grouping - Search result grouping using Independent Component Analysis

    DEFF Research Database (Denmark)

    Lauritsen, Thomas; Kolenda, Thomas

    2002-01-01

    We present a computational simple and efficient approach to unsupervised grouping the search result from any search engine. Along with each group a set of keywords are found to annotate the contents. This approach leads to an interactive search trough a hierarchial structure that is build online....... It is the users task to improve the search, trough expanding the search query using the topic keywords representing the desired groups. In doing so the search engine limits the space of possible search results, virtually moving down in the search hierarchy, and so refines the search....

  18. Social Search: A Taxonomy of, and a User-Centred Approach to, Social Web Search

    Science.gov (United States)

    McDonnell, Michael; Shiri, Ali

    2011-01-01

    Purpose: The purpose of this paper is to introduce the notion of social search as a new concept, drawing upon the patterns of web search behaviour. It aims to: define social search; present a taxonomy of social search; and propose a user-centred social search method. Design/methodology/approach: A mixed method approach was adopted to investigate…

  19. People searching for people: analysis of a people search engine log

    NARCIS (Netherlands)

    Weerkamp, W.; Berendsen, R.; Kovachev, B.; Meij, E.; Balog, K.; de Rijke, M.

    2011-01-01

    Recent years show an increasing interest in vertical search: searching within a particular type of information. Understanding what people search for in these "verticals" gives direction to research and provides pointers for the search engines themselves. In this paper we analyze the search logs of

  20. A hybrid search algorithm for swarm robots searching in an unknown environment.

    Science.gov (United States)

    Li, Shoutao; Li, Lina; Lee, Gordon; Zhang, Hao

    2014-01-01

    This paper proposes a novel method to improve the efficiency of a swarm of robots searching in an unknown environment. The approach focuses on the process of feeding and individual coordination characteristics inspired by the foraging behavior in nature. A predatory strategy was used for searching; hence, this hybrid approach integrated a random search technique with a dynamic particle swarm optimization (DPSO) search algorithm. If a search robot could not find any target information, it used a random search algorithm for a global search. If the robot found any target information in a region, the DPSO search algorithm was used for a local search. This particle swarm optimization search algorithm is dynamic as all the parameters in the algorithm are refreshed synchronously through a communication mechanism until the robots find the target position, after which, the robots fall back to a random searching mode. Thus, in this searching strategy, the robots alternated between two searching algorithms until the whole area was covered. During the searching process, the robots used a local communication mechanism to share map information and DPSO parameters to reduce the communication burden and overcome hardware limitations. If the search area is very large, search efficiency may be greatly reduced if only one robot searches an entire region given the limited resources available and time constraints. In this research we divided the entire search area into several subregions, selected a target utility function to determine which subregion should be initially searched and thereby reduced the residence time of the target to improve search efficiency.

  1. Search Analytics: Automated Learning, Analysis, and Search with Open Source

    Science.gov (United States)

    Hundman, K.; Mattmann, C. A.; Hyon, J.; Ramirez, P.

    2016-12-01

    The sheer volume of unstructured scientific data makes comprehensive human analysis impossible, resulting in missed opportunities to identify relationships, trends, gaps, and outliers. As the open source community continues to grow, tools like Apache Tika, Apache Solr, Stanford's DeepDive, and Data-Driven Documents (D3) can help address this challenge. With a focus on journal publications and conference abstracts often in the form of PDF and Microsoft Office documents, we've initiated an exploratory NASA Advanced Concepts project aiming to use the aforementioned open source text analytics tools to build a data-driven justification for the HyspIRI Decadal Survey mission. We call this capability Search Analytics, and it fuses and augments these open source tools to enable the automatic discovery and extraction of salient information. In the case of HyspIRI, a hyperspectral infrared imager mission, key findings resulted from the extractions and visualizations of relationships from thousands of unstructured scientific documents. The relationships include links between satellites (e.g. Landsat 8), domain-specific measurements (e.g. spectral coverage) and subjects (e.g. invasive species). Using the above open source tools, Search Analytics mined and characterized a corpus of information that would be infeasible for a human to process. More broadly, Search Analytics offers insights into various scientific and commercial applications enabled through missions and instrumentation with specific technical capabilities. For example, the following phrases were extracted in close proximity within a publication: "In this study, hyperspectral images…with high spatial resolution (1 m) were analyzed to detect cutleaf teasel in two areas. …Classification of cutleaf teasel reached a users accuracy of 82 to 84%." Without reading a single paper we can use Search Analytics to automatically identify that a 1 m spatial resolution provides a cutleaf teasel detection users accuracy of 82

  2. KNOWLEDGE UNDERSTANDING AND ADVANCED SEARCHING

    Directory of Open Access Journals (Sweden)

    R Vidya

    2017-04-01

    Full Text Available It’s a comprehensive fact that millions of people around the world surf the Internet for want of answers for their questions. Generally, the questions are asked in the form of Searching or direct questions which follow perfect ontological directions. It is important that the system understands the questions in the right sense and can provide the best answer for all the questions raised in the web forum. One such pragmatic method is required which is expected to provide optimum solution to achieve best answers for questions that not only percepts language but also follows perfect ontological information in accordance with the cyber law. This Proposed Model presents a new dynamic model called Knowledge Understanding and Advance Searching (KUAS that studies the importance of Smart Question Answering with other question answering engines like START and proves to give the optimal solution compared to them.

  3. Target-Searching on Percolation

    International Nuclear Information System (INIS)

    Yang Shijie

    2005-01-01

    We study target-searching processes on a percolation, on which a hunter tracks a target by smelling odors it emits. The odor intensity is supposed to be inversely proportional to the distance it propagates. The Monte Carlo simulation is performed on a 2-dimensional bond-percolation above the threshold. Having no idea of the location of the target, the hunter determines its moves only by random attempts in each direction. For lager percolation connectivity p ∼> 0.90, it reveals a scaling law for the searching time versus the distance to the position of the target. The scaling exponent is dependent on the sensitivity of the hunter. For smaller p, the scaling law is broken and the probability of finding out the target significantly reduces. The hunter seems trapped in the cluster of the percolation and can hardly reach the goal.

  4. Search for leptoquarks at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Huettmann, Antje

    2009-10-15

    A search for first generation leptoquarks was performed in polarized electron-proton collider data recorded with the ZEUS detector at HERA in the years 2003-2007. They were analyzed for final states with an electron and jets or with missing transverse momentum and jets and a search for resonance structures or other deviations from the Standard Model predictions in the spectra of the invariant mass of lepton and jets was performed. No evidence for leptoquark signals was found. The data were combined with the previously taken data at HERA corresponding to an integrated luminosity of 488 pb{sup -1} and limits were set on the Yukawa coupling {lambda} as a function of the leptoquark mass for different leptoquark types within the Buchmueller-Rueckl-Wyler model. (orig.)

  5. Intelligent search in Big Data

    Science.gov (United States)

    Birialtsev, E.; Bukharaev, N.; Gusenkov, A.

    2017-10-01

    An approach to data integration, aimed on the ontology-based intelligent search in Big Data, is considered in the case when information objects are represented in the form of relational databases (RDB), structurally marked by their schemes. The source of information for constructing an ontology and, later on, the organization of the search are texts in natural language, treated as semi-structured data. For the RDBs, these are comments on the names of tables and their attributes. Formal definition of RDBs integration model in terms of ontologies is given. Within framework of the model universal RDB representation ontology, oil production subject domain ontology and linguistic thesaurus of subject domain language are built. Technique of automatic SQL queries generation for subject domain specialists is proposed. On the base of it, information system for TATNEFT oil-producing company RDBs was implemented. Exploitation of the system showed good relevance with majority of queries.

  6. The search for proton decay

    International Nuclear Information System (INIS)

    Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E.; Cline, D.B.

    1994-01-01

    The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-bar n oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade

  7. Heavy Higgs searches. Flavour matters

    International Nuclear Information System (INIS)

    Gori, Stefania; Paul, Ayan

    2017-10-01

    We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.

  8. Serendipity in dark photon searches

    Science.gov (United States)

    Ilten, Philip; Soreq, Yotam; Williams, Mike; Xue, Wei

    2018-06-01

    Searches for dark photons provide serendipitous discovery potential for other types of vector particles. We develop a framework for recasting dark photon searches to obtain constraints on more general theories, which includes a data-driven method for determining hadronic decay rates. We demonstrate our approach by deriving constraints on a vector that couples to the B-L current, a leptophobic B boson that couples directly to baryon number and to leptons via B- γ kinetic mixing, and on a vector that mediates a protophobic force. Our approach can easily be generalized to any massive gauge boson with vector couplings to the Standard Model fermions, and software to perform any such recasting is provided at https://gitlab.com/philten/darkcast https://gitlab.com/philten/darkcast" TargetType="URL"/> .

  9. Search for new heavy techniparticles

    International Nuclear Information System (INIS)

    Baltay, C.; Gordon, H.

    1982-01-01

    In this article, the authors consider in some detail an experiment to search for the Technieta (/sub eta T/), which is expected to be in the 100 to 300 GeV mass range. For the sake of concreteness they use the predictions of the technicolor models; however, it might be better to think of these considerations as an example of the kind of searches that should be carried out with the next generation of hadron-hadron colliders, without putting too much importance on the details of the theoretical models that happen to be in fashion at this time. The general notion of a -- TeV mass scale and the rough value of the coupling strengths of the new mass scale to the present quarks, leptons and gluons seem more reliable than details of the particular models

  10. Heavy Higgs searches. Flavour matters

    Energy Technology Data Exchange (ETDEWEB)

    Gori, Stefania [Cincinnati Univ., OH (United States). Dept. of Physics; Grojean, Christophe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Juste, Aurelio [Institut de Fisica d' Altes Energies (IFAE), Barcelona (Spain); Institucio Catalanade Recerca i Estudis Avancats (ICREA), Barcelona (Spain); Paul, Ayan [INFN, Sezione di Roma (Italy)

    2017-10-15

    We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.

  11. Search for intermediate vector bosons

    International Nuclear Information System (INIS)

    Klajn, D.B.; Rubbia, K.; Meer, S.

    1983-01-01

    Problem of registration and search for intermediate vector bosons is discussed. According to weak-current theory there are three intermediate vector bosons with +1(W + )-1(W - ) and zero (Z 0 ) electric charges. It was suggested to conduct the investigation into particles in 1976 by cline, Rubbia and Makintair using proton-antiproton beams. Major difficulties of the experiment are related to the necessity of formation of sufficient amount of antiparticles and the method of antiproton beam ''cooling'' for the purpose of reduction of its random movements. The stochastic method was suggested by van der Meer in 1968 as one of possible cooling methods. Several large detectors were designed for searching intermediate vector bosons

  12. Characteristic sounds facilitate visual search.

    Science.gov (United States)

    Iordanescu, Lucica; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

    2008-06-01

    In a natural environment, objects that we look for often make characteristic sounds. A hiding cat may meow, or the keys in the cluttered drawer may jingle when moved. Using a visual search paradigm, we demonstrated that characteristic sounds facilitated visual localization of objects, even when the sounds carried no location information. For example, finding a cat was faster when participants heard a meow sound. In contrast, sounds had no effect when participants searched for names rather than pictures of objects. For example, hearing "meow" did not facilitate localization of the word cat. These results suggest that characteristic sounds cross-modally enhance visual (rather than conceptual) processing of the corresponding objects. Our behavioral demonstration of object-based cross-modal enhancement complements the extensive literature on space-based cross-modal interactions. When looking for your keys next time, you might want to play jingling sounds.

  13. Review of dark photon searches

    International Nuclear Information System (INIS)

    Denig, Achim

    2016-01-01

    Dark Photons are hypothetical extra-U(1) gauge bosons, which are motivated by a number of astrophysical anomalies as well as the presently seen deviation between the Standard Model prediction and the direct measurement of the anomalous magnetic moment of the muon, (g − 2)μ. The Dark Photon does not serve as the Dark Matter particle itself, but acts as a messenger particle of a hypothetical Dark Sector with residual interaction to the Standard Model. We review recent Dark Photon searches, which were carried out in a global effort at various hadron and particle physics facilities. We also comment on the perspectives for future invisble searches, which directly probe the existence of Light Dark Matter particles.

  14. Individual Search and Social Networks

    OpenAIRE

    Sanjeev Goyal; Stephanie Rosenkranz; Utz Weitzel; Vincent Buskens

    2014-01-01

    The explosion in online social networks motivates an enquiry into their structure and their welfare effects. A central feature of these networks is information sharing: online social networks lower the cost of getting information from others. These lower costs affect the attractiveness of individual search vis-a-vis a reliance on social networks. The paper reports the findings of an experiment on these effects. Our experiment shows that online networks can have large effects. Information acqu...

  15. Direct search for dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jonghee; /Fermilab

    2009-12-01

    Dark matter is hypothetical matter which does not interact with electromagnetic radiation. The existence of dark matter is only inferred from gravitational effects of astrophysical observations to explain the missing mass component of the Universe. Weakly Interacting Massive Particles are currently the most popular candidate to explain the missing mass component. I review the current status of experimental searches of dark matter through direct detection using terrestrial detectors.

  16. Searching for better plasmonic materials

    DEFF Research Database (Denmark)

    West, P.; Ishii, S.; Naik, G.

    2010-01-01

    Plasmonics is a research area merging the fields of optics and nanoelectronics by confining light with relatively large free-space wavelength to the nanometer scale - thereby enabling a family of novel devices. Current plasmonic devices at telecommunication and optical frequencies face significan...... for realizing optimal plasmonic material properties for specific frequencies and applications, thereby providing a reference for those searching for better plasmonic materials....

  17. Sampling criteria in multicollection searching.

    Science.gov (United States)

    Gilio, A.; Scozzafava, R.; Marchetti, P. G.

    In the first stage of the document retrieval process, no information concerning relevance of a particular document is available. On the other hand, computer implementation requires that the analysis be made only for a sample of retrieved documents. This paper addresses the significance and suitability of two different sampling criteria for a multicollection online search facility. The inevitability of resorting to a logarithmic criterion in order to achieve a "spread of representativeness" from the multicollection is demonstrated.

  18. Money Inventories in Search Equilibrium

    OpenAIRE

    Berentsen, Aleksander

    1998-01-01

    The paper relaxes the one unit storage capacity imposed in the basic search-theoretic model of fiat money with indivisible real commodities and indivisible money. Agents can accumulate as much money as they want. It characterizes the stationary distributions of money and shows that for reasonable parameter values (e.g. production cost, discounting, degree of specialization) a monetary equilibrium exists. There are multiple stationary distributions of a given amount of money, which differ in t...

  19. Search for the eta C

    International Nuclear Information System (INIS)

    Garren, L.A.

    1982-01-01

    In an experiment performed at the Alternating Gradient Synchrotron at Brookhaven National Laboratory, we searched for narrow resonances in the reaction pi minus p -> X n, X -> gamma gamma at 13 GeV. We used a double-arm spectrometer with lead glass and scintillation elements. No resonances were observed above mass 2.8 in the gamma-gamma spectrum. The upper limit for the eta c cross section times branching ratio is 23 pb

  20. Database searches for qualitative research

    OpenAIRE

    Evans, David

    2002-01-01

    Interest in the role of qualitative research in evidence-based health care is growing. However, the methods currently used to identify quantitative research do not translate easily to qualitative research. This paper highlights some of the difficulties during searches of electronic databases for qualitative research. These difficulties relate to the descriptive nature of the titles used in some qualitative studies, the variable information provided in abstracts, and the differences in the ind...

  1. ROLE AND IMPORTANCE OF SEARCH ENGINE OPTIMIZATION

    OpenAIRE

    Gurneet Kaur

    2017-01-01

    Search Engines are an indispensible platform for users all over the globe to search for relevant information online. Search Engine Optimization (SEO) is the exercise of improving the position of a website in search engine rankings, for a chosen set of keywords. SEO is divided into two parts: On-Page and Off-Page SEO. In order to be successful, both the areas require equal attention. This paper aims to explain the functioning of the search engines along with the role and importance of search e...

  2. Measuring Search Frictions Using Japanese Microdata

    DEFF Research Database (Denmark)

    Sasaki, Masaru; Kohara, Miki; Machikita, Tomohiro

    This paper estimates matching functions to measure search frictions in the Japanese labor market and presents determinants of search duration to explain the effect of unemployment benefits on a job seeker’s behavior. We employ administrative micro data that track the job search process of individ......This paper estimates matching functions to measure search frictions in the Japanese labor market and presents determinants of search duration to explain the effect of unemployment benefits on a job seeker’s behavior. We employ administrative micro data that track the job search process...

  3. Further investigation on adaptive search

    Directory of Open Access Journals (Sweden)

    Ming Hong Pi

    2014-05-01

    Full Text Available Adaptive search is one of the fastest fractal compression algorithms and has gained great success in many industrial applications. By substituting the luminance offset by the range block mean, the authors create a completely new version for both the encoding and decoding algorithms. In this paper, theoretically, they prove that the proposed decoding algorithm converges at least as fast as the existing decoding algorithms using the luminance offset. In addition, they prove that the attractor of the decoding algorithm can be represented by a linear combination of range-averaged images. These theorems are very important contributions to the theory and applications of fractal image compression. As a result, the decoding image can be represented as the sum of the DC and AC component images, which is similar with discrete cosine transform or wavelet transform. To further speed up this algorithm and reduce the complexity of range and domain blocks matching, they propose two improvements in this paper, that is, employing the post-quantisation and geometric neighbouring local search to replace the currently used pre-quantisation and the global search, respectively. The corresponding experimental results show the proposed encoding and decoding algorithms can provide a better performance compared with the existing algorithms.

  4. Stop searches in flavourful supersymmetry

    CERN Document Server

    Crivellin, Andreas; Tunstall, Lewis C.

    2016-01-01

    Natural realisations of supersymmetry require light stops ${\\tilde t}_1$, making them a prime target of LHC searches for physics beyond the Standard Model. Depending on the kinematic region, the main search channels are ${\\tilde t_1}\\to t \\tilde \\chi^0_1$, ${\\tilde t_1}\\to W b \\tilde \\chi^0_1$ and ${\\tilde t_1}\\to c \\tilde \\chi^0_1$. We first examine the interplay of these decay modes with ${\\tilde c_1}\\to c \\tilde \\chi^0_1$ in a model-independent fashion, revealing the existence of large regions in parameter space which are excluded for any ${\\tilde t_1}\\to c \\tilde \\chi^0_1$ branching ratio. This effect is then illustrated for scenarios with stop-scharm mixing in the right-handed sector, where it has previously been observed that the stop mass limits can be significantly weakened for large mixing. Our analysis shows that once the LHC bounds from ${\\tilde c_1}\\to c \\tilde \\chi^0_1$ searches are taken into account, non-zero stop-scharm mixing leads only to a modest increase in the allowed regions of parameter...

  5. Semantic search during divergent thinking.

    Science.gov (United States)

    Hass, Richard W

    2017-09-01

    Divergent thinking, as a method of examining creative cognition, has not been adequately analyzed in the context of modern cognitive theories. This article casts divergent thinking responding in the context of theories of memory search. First, it was argued that divergent thinking tasks are similar to semantic fluency tasks, but are more constrained, and less well structured. Next, response time distributions from 54 participants were analyzed for temporal and semantic clustering. Participants responded to two prompts from the alternative uses test: uses for a brick and uses for a bottle, for two minutes each. Participants' cumulative response curves were negatively accelerating, in line with theories of search of associative memory. However, results of analyses of semantic and temporal clustering suggested that clustering is less evident in alternative uses responding compared to semantic fluency tasks. This suggests either that divergent thinking responding does not involve an exhaustive search through a clustered memory trace, but rather that the process is more exploratory, yielding fewer overall responses that tend to drift away from close associates of the divergent thinking prompt. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Searching for Orphan radiation sources

    International Nuclear Information System (INIS)

    Bystrov, Evgenij; Antonau, Uladzimir; Gurinovich, Uladzimir; Kazhamiakin, Valery; Petrov, Vitaly; Shulhovich, Heorhi; Tischenko, Siarhei

    2008-01-01

    Full text: The problem of orphan sources cannot be left unaddressed due high probability of accidental exposure and use of sources for terrorism. Search of objects of this kind is complex particularly when search territory is large. This requires devices capable of detecting sources, identifying their radionuclide composition, and correlating scan results to geographical coordinates and displaying results on a map. Spectral radiation scanner AT6101C can fulfill the objective of search for gamma and neutron radiation sources, radionuclide composition identification, correlation results to geographical coordinates and displaying results on a map. The scanner consists of gamma radiation scintillation detection unit based on NaI(Tl) crystal, neutron detection unit based on two He 3 counters, GPS receiver and portable ruggedized computer. Built-in and application software automates entire scan process, saving all results to memory for further analysis with visual representation of results as spectral information diagrams, count rate profile and gamma radiation dose rates on a geographical map. The scanner informs operator with voice messages on detection of radiation sources, identification result and other events. Scanner detection units and accessories are packed in a backpack. Weighing 7 kg, the scanner is human portable and can be used for scan inside cars. The scanner can also be used for radiation mapping and inspections. (author)

  7. Organizational Search Strategy: An Examination of Interdependencies, Locus and Temporality of Search

    NARCIS (Netherlands)

    Ebrahim, Mahdi

    2017-01-01

    Notwithstanding the ample research on organizational search and its performance implications, the factors that shape the organizations’ search strategy is fairly under-explored. This study investigates how problems’ characteristics influence the managerial decision of searching jointly or

  8. Dyniqx: a novel meta-search engine for metadata based cross search

    OpenAIRE

    Zhu, Jianhan; Song, Dawei; Eisenstadt, Marc; Barladeanu, Cristi; Rüger, Stefan

    2008-01-01

    The effect of metadata in collection fusion has not been sufficiently studied. In response to this, we present a novel meta-search engine called Dyniqx for metadata based cross search. Dyniqx exploits the availability of metadata in academic search services such as PubMed and Google Scholar etc for fusing search results from heterogeneous search engines. In addition, metadata from these search engines are used for generating dynamic query controls such as sliders and tick boxes etc which are ...

  9. Employed and unemployed job search methods: Australian evidence on search duration, wages and job stability

    OpenAIRE

    Colin Green

    2012-01-01

    This paper examines the use and impact of job search methods of both unemployed and employed job seekers. Informal job search methods are associated with relativel high level of job exit and shorter search duration. Job exists through the public employment agency (PEA) display positive duration dependence for the unemployed. This may suggest that the PEA is used as a job search method of last resort. Informal job search methods have lower associated duration in search and higher wages than th...

  10. Modified Parameters of Harmony Search Algorithm for Better Searching

    Science.gov (United States)

    Farraliza Mansor, Nur; Abal Abas, Zuraida; Samad Shibghatullah, Abdul; Rahman, Ahmad Fadzli Nizam Abdul

    2017-08-01

    The scheduling and rostering problems are deliberated as integrated due to they depend on each other whereby the input of rostering problems is a scheduling problems. In this research, the integrated scheduling and rostering bus driver problems are defined as maximising the balance of the assignment of tasks in term of distribution of shifts and routes. It is essential to achieve is fairer among driver because this can bring to increase in driver levels of satisfaction. The latest approaches still unable to address the fairness problem that has emerged, thus this research proposes a strategy to adopt an amendment of a harmony search algorithm in order to address the fairness issue and thus the level of fairness will be escalate. The harmony search algorithm is classified as a meta-heuristics algorithm that is capable of solving hard and combinatorial or discrete optimisation problems. In this respect, the three main operators in HS, namely the Harmony Memory Consideration Rate (HMCR), Pitch Adjustment Rate (PAR) and Bandwidth (BW) play a vital role in balancing local exploitation and global exploration. These parameters influence the overall performance of the HS algorithm, and therefore it is crucial to fine-tune them. The contributions to this research are the HMCR parameter using step function while the fret spacing concept on guitars that is associated with mathematical formulae is also applied in the BW parameter. The model of constant step function is introduced in the alteration of HMCR parameter. The experimental results revealed that our proposed approach is superior than parameter adaptive harmony search algorithm. In conclusion, this proposed approach managed to generate a fairer roster and was thus capable of maximising the balancing distribution of shifts and routes among drivers, which contributed to the lowering of illness, incidents, absenteeism and accidents.

  11. Do two heads search better than one? Effects of student collaboration on web search behavior and search outcomes.

    NARCIS (Netherlands)

    Lazonder, Adrianus W.

    2005-01-01

    This study compared Pairs of students with Single students in web search tasks. The underlying hypothesis was that peer-to-peer collaboration encourages students to articulate their thoughts, which in turn has a facilitative effect on the regulation of the search process as well as search outcomes.

  12. Open meta-search with OpenSearch: a case study

    OpenAIRE

    O'Riordan, Adrian P.

    2007-01-01

    The goal of this project was to demonstrate the possibilities of open source search engine and aggregation technology in a Web environment by building a meta-search engine which employs free open search engines and open protocols. In contrast many meta-search engines on the Internet use proprietary search systems. The search engines employed in this case study are all based on the OpenSearch protocol. OpenSearch-compliant systems support XML technologies such as RSS and Atom for aggregation a...

  13. Miocene freshwater Mollusca from western Brazilian Amazonia

    NARCIS (Netherlands)

    Wesselingh, F.P.; Ranzi, A.; Räsänen, M.E.

    2006-01-01

    Thirteen species of fossil molluscs are reported from the Solimões Formation of western Brazilian Amazonia. Based on mammalian chronology of the Solimões Formation and radiometric ages reported from coeval deposits in adjacent Peru, the age of the fauna is established as Late Miocene. The fauna

  14. Lorentz Spengler's descriptions of chitons (Mollusca: Polyplacophora)

    NARCIS (Netherlands)

    Kaas, P.; Knudsen, J.

    1992-01-01

    The present paper deals with an important Danish paper on the Polyplacophora, published in 1797 by Lorentz Spengler: Udförlig Beskrivelse over det mangeskallede Konkylie-Slaegt, af Linnaeus kaldet Chiton; med endeel nye Arter og Varieteter. -Skrivter af Naturhistorie-Selskabet, 4e Bind, Ie Hefte,

  15. Short Communication Myosotella myosotis (Mollusca: Ellobiidae ...

    African Journals Online (AJOL)

    Myosotella myosotis is shown to be a well-established alien species in South Africa. Discovered in Port Elizabeth more than 100 years ago, it was initially thought to be indigenous and was described under two different names, but subsequent taxonomic work has demonstrated that these are synonyms of the variable and ...

  16. Water Pollution Search | ECHO | US EPA

    Science.gov (United States)

    The Water Pollution Search within the Water Pollutant Loading Tool gives users options to search for pollutant loading information from Discharge Monitoring Report (DMR) and Toxic Release Inventory (TRI) data.

  17. A Novel Personalized Web Search Model

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhengyu; XU Jingqiu; TIAN Yunyan; REN Xiang

    2007-01-01

    A novel personalized Web search model is proposed.The new system, as a middleware between a user and a Web search engine, is set up on the client machine. It can learn a user's preference implicitly and then generate the user profile automatically. When the user inputs query keywords, the system can automatically generate a few personalized expansion words by computing the term-term associations according to the current user profile, and then these words together with the query keywords are submitted to a popular search engine such as Yahoo or Google.These expansion words help to express accurately the user's search intention. The new Web search model can make a common search engine personalized, that is, the search engine can return different search results to different users who input the same keywords. The experimental results show the feasibility and applicability of the presented work.

  18. Mathematical programming solver based on local search

    CERN Document Server

    Gardi, Frédéric; Darlay, Julien; Estellon, Bertrand; Megel, Romain

    2014-01-01

    This book covers local search for combinatorial optimization and its extension to mixed-variable optimization. Although not yet understood from the theoretical point of view, local search is the paradigm of choice for tackling large-scale real-life optimization problems. Today's end-users demand interactivity with decision support systems. For optimization software, this means obtaining good-quality solutions quickly. Fast iterative improvement methods, like local search, are suited to satisfying such needs. Here the authors show local search in a new light, in particular presenting a new kind of mathematical programming solver, namely LocalSolver, based on neighborhood search. First, an iconoclast methodology is presented to design and engineer local search algorithms. The authors' concern about industrializing local search approaches is of particular interest for practitioners. This methodology is applied to solve two industrial problems with high economic stakes. Software based on local search induces ex...

  19. Model of intelligent information searching system

    International Nuclear Information System (INIS)

    Yastrebkov, D.I.

    2004-01-01

    A brief description of the technique to search for electronic documents in large archives as well as drawbacks is presented. A solution close to intelligent information searching systems is proposed. (author)

  20. Search Engines: Gateway to a New ``Panopticon''?

    Science.gov (United States)

    Kosta, Eleni; Kalloniatis, Christos; Mitrou, Lilian; Kavakli, Evangelia

    Nowadays, Internet users are depending on various search engines in order to be able to find requested information on the Web. Although most users feel that they are and remain anonymous when they place their search queries, reality proves otherwise. The increasing importance of search engines for the location of the desired information on the Internet usually leads to considerable inroads into the privacy of users. The scope of this paper is to study the main privacy issues with regard to search engines, such as the anonymisation of search logs and their retention period, and to examine the applicability of the European data protection legislation to non-EU search engine providers. Ixquick, a privacy-friendly meta search engine will be presented as an alternative to privacy intrusive existing practices of search engines.