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Sample records for larval chironomids raised

  1. The influence of environmental factors and dredging on chironomid larval diversity in urban drainage systems in polders strongly influenced by seepage from large rivers

    DEFF Research Database (Denmark)

    Vermonden, K.; Brodersen, Klaus Peter; Jacobsen, Dean

    2011-01-01

    , in urban waters strongly influenced by seepage of large rivers. Chironomid assemblages were studied in urban surface-water systems (man-made drainage ditches) in polder areas along lowland reaches of the rivers Rhine-Meuse in The Netherlands. Multivariate analysis was used to identify the key environmental...... factors. Taxon richness, Shannon index (H'), rareness of species, and life-history strategies at urban locations were compared with available data from similar man-made water bodies in rural areas, and the effectiveness of dredging for restoring chironomid diversity in urban waters was tested. Three...... diversity of chironomid communities in urban waters affected by nutrient-rich seepage or inlet of river water...

  2. Morphological identification and COI barcodes of adult flies help determine species identities of chironomid larvae (Diptera, Chironomidae).

    Science.gov (United States)

    Failla, A J; Vasquez, A A; Hudson, P; Fujimoto, M; Ram, J L

    2016-02-01

    Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or 'species group' level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor

  3. Relation of chironomids with Aeromonas species

    Directory of Open Access Journals (Sweden)

    Sivan eLaviad

    2016-05-01

    Full Text Available Chironomids (Diptera: Chironomidae, also known as non-biting midges, are one of the most abundant groups of insects in aquatic habitats. They undergo a complete metamorphosis of four life stages of which three are aquatic (egg, larva, pupa, and the adult emerges into the air. Chironomids serve as a natural reservoir of Aeromonas and Vibrio cholerae species. Here we review existing knowledge about the mutual relations between Aeromonas species and chironomids. Using 454-pyrosequencing of the 16S rRNA gene, we found that the prevalence of Aeromonas species in the insects’ egg masses and larvae was 1.6% and 3.3% of the insects’ endogenous microbiota, respectively. Aeromonas abundance per egg mass remained stable during a six-month period of bacterial monitoring. Different Aeromonas species were isolated and some demonstrated the ability to degrade the insect’s egg masses and to prevent eggs hatching. Chitinase was identified as the enzyme responsible for the egg mass degradation. Different Aeromonas species isolated from chironomids demonstrated the potential to protect their host from toxic metals. Aeromonas is a causative agent of fish infections. Fish are frequently recorded as feeding on chironomids. Thus, fish might be infected with Aeromonas species via chironomid consumption. Aeromonas strains are also responsible for causing gastroenteritis and wound infections in humans. Different virulence genes were identified in Aeromonas species isolated from chironomids. Chironomids may infest drinking water reservoirs, hence be the source of pathogenic Aeromonas strains in drinking water. Chironomids and Aeromonas species have a complicated mutual relationship.

  4. Common antigenic determinants of haemoglobin as basis of immunological cross-reactivity between chironomid species (Diptera, Chironomidae): studies with human and animal sera.

    Science.gov (United States)

    Baur, X; Dewair, M; Haegele, K; Prelicz, H; Scholl, A; Tichy, H

    1983-01-01

    Chironomids, of which approximately 10,000 species exist, are reported to cause severe immediate type allergic diseases in man. In the present study, immunological cross-reactivity between 14 chironomid species from different continents was proven by RAST inhibition, double immunodiffusion and a new allergoprint technique, based upon PAGE separation of insect crude extracts. Using isolated chironomid haemoglobins and sera of sensitized persons, as well as rabbit antibodies against larval crude extract or against the haemoglobin fraction of Chironomus thummi, it could be proven that cross-reactivity derives at least predominantly from haemoglobin components with common antigenic determinants in the different species. Images Fig. 2 Fig. 7 Fig. 8 Fig. 9 PMID:6197219

  5. Influence of selected biotopes on chironomid-based bioassessment ...

    African Journals Online (AJOL)

    ... three distinct biotopes, i.e., stones, vegetation and sediments. In this study, the influence of reducing the numbers of biotopes on chironomid-based bioassessment of pollution in the Swartkops River was investigated. This paper addresses the following questions: (i) can the chironomid species assemblage from any single ...

  6. Annual Survey of Horsehair Worm Cysts in Northern Taiwan, with Notes on a Single Seasonal Infection Peak in Chironomid Larvae (Diptera: Chironomidae).

    Science.gov (United States)

    Chiu, Ming-Chung; Huang, Chin-Gi; Wu, Wen-Jer; Shiao, Shiuh-Feng

    2016-06-01

    The life cycle of the freshwater horsehair worm typically includes a free-living phase (adult, egg, larva) and a multiple-host parasitic phase (aquatic paratenic host, terrestrial definitive host). Such a life cycle involving water and land can improve energy flow in riparian ecosystems; however, its temporal dynamics in nature have rarely been investigated. This study examined seasonal infection with cysts in larval Chironominae (Diptera: Chironomidae) in northern Taiwan. In the larval chironomids, cysts of 3 horsehair worm species were identified. The cysts of the dominant species were morphologically similar to those of Chordodes formosanus. Infection with these cysts increased suddenly and peaked 2 mo after the reproductive season of the adult horsehair worms. Although adult C. formosanus emerged several times in a year, only 1 distinct infection peak was detected in September in the chironomid larvae. Compared with the subfamily Chironominae, samples from the subfamilies Tanypodinae and Orthocladiinae were less parasitized. This indicates that the feeding behavior of the chironomid host likely affects horsehair worm cyst infections; however, bioconcentration in predatory chironomids was not detected.

  7. [Toxicity and influencing factors of liquid chlorine on chironomid larvae].

    Science.gov (United States)

    Sun, Xing-Bin; Cui, Fu-Yi; Zhang, Jin-Song; Guo, Zhao-Hai; Xu, Feng; Liu, Li-Jun

    2005-09-01

    The excessive propagation of Chironomid larvae (red worm) in the sedimentation tanks is a difficult problem for the normal function of waterworks. The toxic effect of liquid chlorine on the different instar larvae of Chironomid was studied using distilled water as test sample. Furthermore, the effect of pH value, organic matter content, ammonia nitrogen, and algae content on toxicity of liquid chlorine was observed. The results show that the tolerance of Chironomid larvae to liquid chlorine is strengthened with the increase in instar. The 24h semi-lethal concentration (LC50) of liquid chlorine to the 4th instar larvae of Chironomid is 3.39 mg/L. Low pH value and high algae content are helpful to improve the toxic effect of liquid chlorine to Chironomid larvae. In neutral water body, the increase in organic matter content results in the decrease in the death rate of Chironomid larvae. The toxicity of liquid chlorine differs greatly in different concentrations of ammonia nitrogen. The death rate of the 4th instar larvae of Chironomid in raw water is higher by contrast with that in sedimentation tanks water for 24h disposal with various amount of liquid chlorine.

  8. Avaliação do desenvolvimento larval de Anopheles darlingi criado em laboratório sob diferentes dietas Evaluation of the larval development of Anopheles darlingi (Diptera - Culicidae raised in the laboratory on different diets

    Directory of Open Access Journals (Sweden)

    Eduardo Sterlino Bergo

    1990-04-01

    Full Text Available São testadas três dietas para larvas de A. darlingi, buscando-se os seguintes parâmetros indicativos de desenvolvimento nesta fase: tempo de evolução total e de cada estádio, sobrevivência ao estádio, diária e total. A metodologia utilizada na determinação desses parâmetros constitui-se da combinação de dois métodos de análise da estatística vital, adaptados ao estudo de populações mantidas em laboratório. Os tempos de evolução total e de cada estádio foram determinados gráficamente a partir das curvas de tendência dos estádios medianos da colônia, em inspeções sucessivas. Os valores de sobrevivência diária, ao estádio e total foram calculados a partir de tábuas de sobrevivência. Os resultados permitiram eleger a dieta composta de uma parte de farinha de peixe para duas partes de farinha de pão e duas partes de germe de trigo como a mais adequada ao desenvolvimento larval, com duração de 12,9 dias entre o primerio estádio e a emersão do adulto e sobrevivência total de 95%.Three diets for A. darlingi larvae were tested in order to arrive at the following parameters indicative of development in this phase: length of time, both for overall as for each stage of evolution and daily and total stage-survival. A methodology which combined two vital statistical methods of analysis, adjusted to the study of populations under laboratory conditions, was used for determining these parameters. The length of time for overall and for each stage of, evolution were graphically assessed on the basis of trend curves of colony median stages, in sequential surveys. Values for the total and the daily stage-survival were stimated from survival tables. Results permitted the selection of the most adequate diet for the larval development as that composed of one part of fish flour to two parts of bread flour and two parts of a heat germ, giving an average length of 12.9 days between the first larval stage and the emergent adult

  9. Chironomid midges (Diptera, chironomidae) show extremely small genome sizes.

    Science.gov (United States)

    Cornette, Richard; Gusev, Oleg; Nakahara, Yuichi; Shimura, Sachiko; Kikawada, Takahiro; Okuda, Takashi

    2015-06-01

    Chironomid midges (Diptera; Chironomidae) are found in various environments from the high Arctic to the Antarctic, including temperate and tropical regions. In many freshwater habitats, members of this family are among the most abundant invertebrates. In the present study, the genome sizes of 25 chironomid species were determined by flow cytometry and the resulting C-values ranged from 0.07 to 0.20 pg DNA (i.e. from about 68 to 195 Mbp). These genome sizes were uniformly very small and included, to our knowledge, the smallest genome sizes recorded to date among insects. Small proportion of transposable elements and short intron sizes were suggested to contribute to the reduction of genome sizes in chironomids. We discuss about the possible developmental and physiological advantages of having a small genome size and about putative implications for the ecological success of the family Chironomidae.

  10. Chironomid distribution along a pollution gradient in Ethiopian rivers ...

    African Journals Online (AJOL)

    Water pollution resulting from the rapidly intensifying use of freshwater resources in Ethiopia is increasing the need for continuous follow-up and monitoring of the country's aquatic ecosystems, in order to maintain their biological diversity and water quality. Chironomids (non-biting dipteran midges) are often used for ...

  11. Habitat selection by chironomid larvae: fast growth requires fast food.

    NARCIS (Netherlands)

    de Haas, E.M.; Wagner, C.; Koelmans, A.A.; Kraak, M.H.S.; Admiraal, W.

    2006-01-01

    1. Sediments have been considered as a habitat, a cover from predators and a source of food, but also as a source of potential toxic compounds. Therefore, the choice of a suitable substrate is essential for the development of chironomids. 2. For the midge Chironomus riparius (Meigen 1804) the growth

  12. CHIRONOMID EMERGENCE AND RELATIVE EMERGENT BIOMASS FROM TWO ALABAMA STREAMS

    Science.gov (United States)

    Chironomid pupal exuviae were sampled monthly using drift nets and hand sieves over an annual cycle from Hendrick Mill Branch (HMB; Blount County, AL) and Payne Creek (PC; Hale County, AL). Taxon richness, community composition, and emergence phonologies were similar despite mar...

  13. Response of chironomid species (Diptera, Chironomidae to water temperature: effects on species distribution in specific habitats

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    L. Marziali

    2013-09-01

    Full Text Available The response of 443 chironomid species to water temperature was analyzed, with the aim of defining their thermal optimum, tolerance limits and thermal habitat. The database included 4442 samples mainly from Italian river catchments collected from the 1950s up to date. Thermal preferences were calculated separately for larval and pupal specimens and for different habitats: high altitude and lowland lakes in the Alpine ecoregion; lowland lakes in the Mediterranean ecoregion; heavily modified water bodies; kryal, krenal, rhithral and potamal in running waters. Optimum response was calculated as mean water temperature, weighted by species abundances; tolerance as weighted standard deviation; skewness and kurtosis as 3rd and 4th moment statistics. The responses were fitted to normal uni- or plurimodal Gaussian models. Cold stenothermal species showed: i unimodal response, ii tolerance for a narrow temperature range, iii optima closed to their minimum temperature values, iv leptokurtic response. Thermophilous species showed: i optima at different temperature values, ii wider tolerance, iii optima near their maximum temperature values, iv platikurtic response, often fitting a plurimodal model. As expected, lower optima values and narrower tolerance were obtained for kryal and krenal, than for rhithral, potamal and lakes. Thermal response curves were produced for each species and were discussed according to species distribution (i.e. altitudinal range in running water and water depth in lakes, voltinism and phylogeny. Thermal optimum and tolerance limits and the definition of the thermal habitat of species can help predicting the impact of global warming on freshwater ecosystems.

  14. An intercontinental comparison of chironomid palaeotemperature inference models: Europe vs North America

    NARCIS (Netherlands)

    Lotter, A.F.; Walker, I.R.; Brooks, S.J.; Hofmann, W.

    1999-01-01

    Chironomid-temperature inference models based on North American, European and combined surface sediment training sets were compared to assess the overall reliability of their predictions. Between 67 and 76% of the major chironomid taxa in each data set showed a unimodal response to July

  15. Oxygen Isotopes Archived in Subfossil Chironomids: Advancing a Promising Proxy for Lake Water Isotopes

    Science.gov (United States)

    Lasher, G. E.; Axford, Y.; Blair, N. E.

    2017-12-01

    Oxygen isotopes measured in subfossil chironomid head capsules (aquatic insect remains) in lake sediments are beginning to offer paleoclimate insights from previously under-studied areas of the world. Since the first published pilot study demonstrated the potential of chironomid δ18O to record lake water δ18O (Wooller et al., 2004), subsequent work has refined our understanding of this proxy: confirming via lab cultures that growth water controls head capsule δ18O (Wang et al., 2009), refining laboratory pretreatment protocols, and further validating the method by demonstrating strong agreement between carbonate and chironomid-derived paleo-isotope records (Verbruggen et al., 2009, 2010, 2011). However, outstanding questions remain, including the seasonality of chironomid growth, possible species-dependent vital effects, and diagenetic effects on the protein-chitin complex that comprise chironomid cuticles. To address some of these questions, we summarize available data from paired modern chironomid-lake water δ18O values from around the world and discuss climatic and environmental factors affecting chironomid isotopic signatures. We also present new data on the resistance of these subfossils to diagenesis and degradation throughout the late Quaternary using Fourier Transform Infrared Spectroscopy (FT-IR) and Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) of chironomid remains up to >100,000 years old. As chironomids are nearly ubiquitous in lakes globally and, we argue, molecularly stable through glacial and interglacial cycles, this proxy has the potential to greatly expand the spatial and temporal resolution of Quaternary paleo-isotopes and thus climate records. In addition to reviewing and presenting new methodological advances, we also present applications of chironomid δ18O from millennial- to centennial-scale Holocene Greenland lake records.

  16. Chironomid (Diptera, Chironomidae species assemblages in northeastern Algerian hydrosystems

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    N. Chaib

    2013-04-01

    Full Text Available The aim of this paper was to analyze the distribution of chironomids (Diptera, Chironomidae, and determine their substrate preferences, from two hydrosystems located in northeastern Algeria: the Kebir-East and the Seybouse wadis. Sixty-five species were recorded in 49 sampling sites distributed along the main courses of the two hydrographic nets and their tributaries. The majority of taxa comprised cosmopolitan species widely distributed along these two hydrosystems. Cricotopus (Cricotopus bicinctus showed the highest abundance and frequency of occurrence (29.52% and was widespread in almost all the sampling sites. Species richness ranged from 4 to 23, Shannon diversity between 0.15 and 0.90, Evenness from 0.23 to 1. A cluster analysis was carried out to represent the different groups of sites sharing similar species composition. Agglomerative cluster analysis grouped the sampling sites into four clusters according to the community data. An Indval analysis was then carried out to detect indicator species for each group of the sampling sites. Cricotopus (Isocladius sylvestris was indicator of the first group of the sampling sites. Orthocladius pedestris, Rheocricotopus chalybeatus and C. bicinctus were indicators of the second group, and Polypedilum cultellatum of the third group. The fourth group was not characterized by any species. Indval analysis allowed also to determine species preferences for substrate size: Corynoneura scutellata and Dicrotendipes nervosus emphasized a preference to fine gravel, and Glyptotendipes pallens to fine sand.

  17. Seasonal variation in Chironomid emergence from coastal pools

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    Alexander T. Egan

    2015-07-01

    Full Text Available Understanding the phenology of emergences can be useful in determining seasonal chironomid life cycle patterns, which are often influenced by ice cover and temperature in cold climates. Lake Superior is the largest lake in North America and with a mean surface temperature of 3.9 °C influences regional climate. Coastal pools at Isle Royale, a wilderness archipelago in the northern part of the lake, occur in dense patches on low-gradient volcanic bedrock between the lakeshore and forest, creating variable microhabitats for Chironomidae. Four sites were sampled monthly from April to October, 2010. Surface-floating pupal exuviae were collected from a series of pools in two zones: a lower zone near the lake influenced by wave splash, and an upper zone near the forest and influenced by upland runoff. We used Jaccard’s and Whittaker’s diversity indexes to test community similarity across months. Temperature loggers in pools collected hourly readings for most of the study. Assemblage emergences were stable in upper pools, with significant similarity across late spring and summer months. Assemblages were seasonally variable in lower pools, with significant dissimilarity across spring, summer, and fall months. Few species in either zone were unique to spring or fall months. However, many summer species in the splash zone had a narrow emergence period occurring during calm weather following distinct increases in mean water temperature. Regardless of input of cold lake water to the lower zone, pools from both zones generally had corresponding temperature trends.

  18. Chironomid-based water depth reconstructions: an independent evaluation of site-specific and local inference models

    NARCIS (Netherlands)

    Engels, S.; Cwynar, L.C.; Rees, A.B.H.; Shuman, B.N.

    2012-01-01

    Water depth is an important environmental variable that explains a significant portion of the variation in the chironomid fauna of shallow lakes. We developed site-specific and local chironomid water-depth inference models using 26 and 104 surface-sediment samples, respectively, from seven

  19. Rapid genetic erosion in pollutant-exposed experimental chironomid populations

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Carsten [Abteilung Okologie und Evolution, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: cnowak@senckenberg.de; Vogt, Christian [Abteilung Aquatische Okotoxikologie, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: vogt@bio.uni-frankfurt.de; Pfenninger, Markus [Abteilung Okologie und Evolution, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: pfenninger@bio.uni-frankfurt.de; Schwenk, Klaus [Abteilung Okologie und Evolution, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: k.schwenk@bio.uni-frankfurt.de; Oehlmann, Joerg [Abteilung Aquatische Okotoxikologie, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: oehlmann@bio.uni-frankfurt.de; Streit, Bruno [Abteilung Okologie und Evolution, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: streit@bio.uni-frankfurt.de; Oetken, Matthias [Abteilung Aquatische Okotoxikologie, Institut fuer Okologie, Evolution und Diversitaet, J. W. Goethe-Universitaet Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main (Germany)], E-mail: oetken@bio.uni-frankfurt.de

    2009-03-15

    Few studies have evaluated how effectively environmental contamination may reduce genetic diversity of a population. Here, we chose a laboratory approach in order to test if tributyltin (TBT) exposure at environmentally relevant concentrations leads to reduced genetic variation in the midge Chironomus riparius. Two TBT-exposed and two unexposed experimental populations were reared simultaneously in the laboratory for 12 generations. We recorded several life-history traits in each generation and monitored genetic variation over time using five variable microsatellite markers. TBT-exposed strains showed increased larval mortality (treatments: 43.8%; controls: 27.8%), slightly reduced reproductive output, and delayed larval development. Reduction of genetic variation was strongest and only significant in the TBT-exposed strains (treatments: -45.9%, controls: -24.4% of initial heterozygosity) after 12 generations. Our findings document that chemical pollution may lead to a rapid decrease in genetic diversity, which has important implications for conservation strategies and ecological management in polluted environments. - Chronic TBT exposure reduces allelic variation at five variable microsatellite loci in experimental populations of Chironomus riparius.

  20. Rapid genetic erosion in pollutant-exposed experimental chironomid populations

    International Nuclear Information System (INIS)

    Nowak, Carsten; Vogt, Christian; Pfenninger, Markus; Schwenk, Klaus; Oehlmann, Joerg; Streit, Bruno; Oetken, Matthias

    2009-01-01

    Few studies have evaluated how effectively environmental contamination may reduce genetic diversity of a population. Here, we chose a laboratory approach in order to test if tributyltin (TBT) exposure at environmentally relevant concentrations leads to reduced genetic variation in the midge Chironomus riparius. Two TBT-exposed and two unexposed experimental populations were reared simultaneously in the laboratory for 12 generations. We recorded several life-history traits in each generation and monitored genetic variation over time using five variable microsatellite markers. TBT-exposed strains showed increased larval mortality (treatments: 43.8%; controls: 27.8%), slightly reduced reproductive output, and delayed larval development. Reduction of genetic variation was strongest and only significant in the TBT-exposed strains (treatments: -45.9%, controls: -24.4% of initial heterozygosity) after 12 generations. Our findings document that chemical pollution may lead to a rapid decrease in genetic diversity, which has important implications for conservation strategies and ecological management in polluted environments. - Chronic TBT exposure reduces allelic variation at five variable microsatellite loci in experimental populations of Chironomus riparius

  1. Induction of mouthpart deformities in chironomid larvae exposed to contaminated sediments.

    NARCIS (Netherlands)

    Di Veroli, A.; Goretti, E.; León Paumen, M.; Kraak, M.H.S.; Admiraal, W.

    2012-01-01

    The aim of the present study was to improve the cause-effect relationship between toxicant exposure and chironomid mouthpart deformities, by linking induction of mouthpart deformities to contaminated field sediments, metal mixtures and a mutagenic polycyclic aromatic compound metabolite (acridone).

  2. The role of pH in structuring communities of Maine wetland macrophytes and chironomid larvae (Diptera)

    Science.gov (United States)

    Woodcock, T.S.; Longcore, J.R.; McAuley, D.G.; Mingo, T.M.; Bennatti, C.R.; Stromborg, K.L.

    2005-01-01

    Aquatic vascular plants, or macrophytes, are an important habitat component for many wetland organisms, and larvae of chironomid midges are ubiquitous components of wetland fauna. Many chironomids are primary consumers of algae and detritus and form an essential energetic link between allochthonous and autochthonous primary production and higher trophic levels, while others are predators and feed on smaller invertebrates. Live macrophytes serve mostly as habitat, whereas plant detritus serves as both habitat and as a food source. Assemblages of macrophytes and chironomid larvae were surveyed in ten Maine wetlands, five with low pH (5.5), and explained in terms of physical and chemical habitat variables. Macrophyte richness was significantly greater, and richness of chironomid larvae was lower, in low pH wetlands. There was no difference in chironomid abundance related to pH. However, community structure was related to pH, suggesting that competitive dominance of a few taxa was responsible for lower richness in low pH wetlands, whereas competition was weaker in high pH wetlands, making coexistence of more chironomid taxa possible. An examination of individual chironomid taxa by stepwise multiple regression showed that distribution of most taxa was controlled by water chemistry variables and macrophyte habit (i.e., floating, submergent).

  3. Assessing lake eutrophication using chironomids: understanding the nature of community response in different lake types

    DEFF Research Database (Denmark)

    Langdon, P. G.; Ruiz, Z.; Brodersen, K. P.

    2006-01-01

    in the original calibration or extended datasets. However, since the transfer functions are based on weighted averages of the trophic optima for the taxa present and not on community similarities, reasonable downcore inferences were produced. Ordination analyses also showed that the lakes retain their 'identity......1. Total phosphorus (TP) and chlorophyll a (Chl a) chironomid inference models ( Brodersen & Lindegaard, 1999 ; Brooks, Bennion & Birks, 2001 ) were used in an attempt to reconstruct changes in nutrients from three very different lake types. Both training sets were expanded, particularly at the low....... A response to nutrients (TP or total nitrogen (TN) ) at this site is also indirect, and the TP reconstruction therefore cannot be reliably interpreted. The third lake, March Ghyll Reservoir has little change in historic chironomid communities, suggesting that this well mixed, relatively unproductive lake has...

  4. A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650

    Science.gov (United States)

    Langdon, P. G.; Caseldine, C. J.; Croudace, I. W.; Jarvis, S.; Wastegård, S.; Crowford, T. C.

    2011-05-01

    Few studies currently exist that aim to validate a proxy chironomid-temperature reconstruction with instrumental temperature measurements. We used a reconstruction from a chironomid percentage abundance data set to produce quantitative summer temperature estimates since AD 1650 for NW Iceland through a transfer function approach, and validated the record against instrumental temperature measurements from Stykkishólmur in western Iceland. The core was dated through Pb-210, Cs-137 and tephra analyses (Hekla 1693) which produced a well-constrained dating model across the whole study period. Little catchment disturbance, as shown through geochemical (Itrax) and loss-on-ignition data, throughout the period further reinforce the premise that the chironomids were responding to temperature and not other catchment or within-lake variables. Particularly cold phases were identified between AD 1683-1710, AD 1765-1780 and AD 1890-1917, with relative drops in summer temperatures in the order of 1.5-2°C. The timing of these cold phases agree well with other evidence of cooler temperatures, notably increased extent of Little Ice Age (LIA) glaciers. Our evidence suggests that the magnitude of summer temperature cooling (1.5-2°C) was enough to force LIA Icelandic glaciers into their maximum Holocene extent, which is in accordance with previous modelling experiments for an Icelandic ice cap (Langjökull).

  5. Assessing the effects of climate and volcanism on diatom and chironomid assemblages in an Andean lake near Quito, Ecuador

    Directory of Open Access Journals (Sweden)

    Neal Michelutti

    2015-12-01

    Full Text Available The tropical Andes are undergoing climate changes that rival those occurring anywhere else on the planet, and are likely to have profound consequences for ecosystems. Paleolimnological investigations of remote mountain lakes can provide details of past environmental change, especially where monitoring data are absent. Here, we reconstruct fossil diatom and chironomid communities spanning the last several hundred years from an Andean lake located in an ecological reserve near Quito, Ecuador. Both diatoms and chironomids recorded assemblage shifts reflective of changing climate conditions. The diatoms are likely responding primarily to temperature-related limnological changes, recording an increase in the number of planktonic taxa in the most recent sediments. This change is consistent with warmer conditions that result in enhanced periods of thermal stratification, allowing planktonic species to proliferate. The chironomids appear to respond mainly to a change in precipitation regime, recording a greater number of terrestrial and semi-terrestrial taxa that have been transported to the lake. A thick tephra deposit at the base of the sediment core affected both diatom and chironomid assemblages. The diatoms registered a change in species composition highlighting the ability of certain taxa to rapidly colonize new environments. In contrast, the chironomids showed a marked drop in abundance immediately following the tephra, but no change in species composition. In both cases the ecological response was short-lived, illustrating the resiliency of the lake to return to baseline conditions following volcanic inputs.

  6. The response of chironomid assemblages to mineral richness gradient in the Western Carpathian helocrenes

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    Vít Syrovátka

    2012-10-01

    Full Text Available Chironomid assemblages of helocrene springs were investigated in the Western Carpathians in order to identify potential effect of water mineral richness on the taxonomic structure of the assemblages. A complex gradient considering water chemistry and substratum was used as a measure of basicity (mineral richness. Taxonomic structure, total abundance and abundance of most frequent taxa were related to this gradient with regards to two contrasting habitats: trickle (A and water-loged soil with standing water (B. The variance in chironomid assemblage attributable to basicity was estimated and tested via PERMANOVA as well as the possible effect of the other environmental variables. The response of individual taxa was examined using GAM. The results indicate a strong relationship between basicity and substratum characteristics, with coarser mineral substrata at basic and high amount of organic matter at acidic conditions. Although water chemistry was correlated with and inseparable from these substratum properties, it could not be substituted with them, as they discriminated well only between acidic and basic springs, but did not follow the basicity gradient in either acidic or basic group of springs. Chironomid assemblage showed a strong and systematic response to the complex gradient of mineral richness, which explained the largest portion of variance in both the habitat A and B faunal data and was projected on the first axes of both NMDS ordinations. The assemblage response could be documented by the preference of several taxa for particular mineral richness conditions, while the number of taxa seemed to be highest in the middle of the basicity gradient. As only 17 samples were analysed so far, the results are considered preliminary and, hopefully, more confident results will be available in near future.doi: 10.5324/fn.v31i0.1403.Published online: 17 October 2012.

  7. Some new records of chironomids (Diptera: Chironomidae from the Czech Republic

    Directory of Open Access Journals (Sweden)

    Bitušík Peter

    2016-09-01

    Full Text Available Six chironomid species: Paraboreochlus minutissimus (Strobl, 1894, Trissopelopia longimanus (Staeger 1839, Boreoheptagyia monticola (Serra-Tosio, 1964, Cricotopus (s.str. similis Goetghebuer 1921, Heleniella serratosioi Ringe, 1976, Krenosmittia camptophleps (Edwards, 1929, were recorded in Czech Republic for the first time. The pupal exuviae were collected in July 2009 from Otava River in the vicinity of Rejštejn village in the central part of the Bohemian Forest. The notes on known distribution and ecology of the species are presented.

  8. Stable isotopic analysis of fossil chironomids as an approach to environmental reconstruction: state of development and future challenges

    Directory of Open Access Journals (Sweden)

    Oliver Heiri

    2012-10-01

    Full Text Available Remains of chironomid larvae, especially their strongly sclerotized head capsules, can be found abundantly and well preserved in most lake sediment records. These remains mainly consist of chitin and proteins and, since their chemical composition does not seem to be strongly affected by decompositional processes, they can be used to develop palaeoenvironmental reconstructions based on their stable isotopic composition. Here we review available stable isotope studies based on fossil chironomids and indicate future research necessary to further develop this still relatively new research approach. Efforts to produce stable isotope records based on fossil chironomids have mainly examined the elements H, N, C, and O. They have focussed on (1 developing the methodology for preparing samples for isotopic analysis, (2 laboratory studies cultivating chironomid larvae under controlled conditions to determine the factors affecting their stable isotopic composition, (3 ecosystem-scale studies relating stable isotopic measurements of fossil chironomid assemblages to environmental conditions, and (4 developing first down-core records describing past changes in the stable isotopic composition of chironomid assemblages. These studies have shown that chemical sample pretreatment may affect the isotopic composition for some elements. Laboratory runs suggest that the diet of the larvae influences their stable isotopic composition for H, N, C and O, whereas stable isotopes in the ambient water also strongly influence their oxygen and to a lesser extent hydrogen isotopic composition. These experiments also indicate only minor offsets between the nitrogen and carbon isotopic composition of chironomid soft tissue and the fossilizing head capsules, whereas for hydrogen and oxygen this offset remains to be explored. Though few datasets have been published, the available ecosystem studies and developed down-core sediment records indicate that stable isotopes in

  9. Iron-coupled inactivation of phosphorus in sediments by macrozoobenthos (chironomid larvae) bioturbation: Evidences from high-resolution dynamic measurements

    International Nuclear Information System (INIS)

    Chen, Musong; Ding, Shiming; Liu, Ling; Xu, Di; Han, Chao; Zhang, Chaosheng

    2015-01-01

    The effects of chironomid larvae bioturbation on the lability of phosphorus (P) in sediments were investigated through sediment incubation for 140 days. High-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques were applied to obtain soluble and labile P/Fe profiles at a millimeter resolution, respectively. The larvae bioturbation decreased concentrations of soluble/labile P and Fe by up to over half of the control at the sediment depths of influence up to 70 and 90 mm respectively. These effects continued over 116 days and disappeared on the 140th days due to eclosion of chironomid larvae. Labile P was highly correlated with labile Fe, while a weak correlation was observed between soluble P and soluble Fe. It was concluded that Fe(II) oxidation and its enhanced adsorption were the major mechanisms responsible for the decreases of soluble and labile P. - Highlights: • High resolution techniques were employed to study bioturbation effects on P. • Larvae bioturbation decreased the concentrations of soluble/labile P and Fe. • Bioturbation effects continued over 116 days and disappeared on the 140th days. • Labile P was more sensitive than pore water SRP in response to bioturbation. • It proved the mechanism of Fe-coupled inactivation of P in bioturbation sediments. - Chironomid larvae bioturation decreased the lability of P in sediments from Fe(II) oxidation and enhanced adsorption of P

  10. Calcified aquatic insect larval constructions in the Pleistocene tufa of Jebel El Mida, Gafsa, southern Tunisia: Recognition and paleoenvironmental significance

    Science.gov (United States)

    Ben Ahmed, Walid; Henchiri, Mohsen; Mastouri, Amna; Slim S'himi, Najet

    2018-04-01

    Calcified aquatic larval cases were recognized and identified in the Pleistocene tufa masses of Jebel El Mida, Gafsa, southern Tunisia. These larval constructions belong to three main insect families: caddisflies (Trichoptera, Hydropsychidae), midges (Diptera, Chironomidae) and aquatic moths (Lepidoptera, Pyralidae) that inhabited tubes in the tufa and spun nets. Each insect community has its distinctive characteristics of larval constructions that allow their recognition. The larval constructions recognized comprise fixed and portable (for caddisflies) dwelling cases and silken retreats and feeding capture nets. These last-mentioned are almost completely eroded and only remnants are preserved. The spatial distribution of these larval cases within the tufa is not random but, rather imposed by some specific paleohydraulic conditions. It's the reason why aquatic insect larval constructions are considered as prominent tool for the reconstruction of tufa and travertine depositional environments. Chironomid fixed dwelling cases (diameters range from 0.6 mm for clustered tubes to 3 mm) indicate the deposition of tufa under lotic (flowing) or lentic (standing) water conditions. The later hydraulic condition is shared with hydropsychids with fixed retreats (0.2-4 mm in diameter). Portable case-building caddisflies (case length ranging from 5 to 20 mm, and diameter from 3 to 5 mm at the cephalic end) prefer lentic conditions and are almost completely missing in high-energy flowing water locations that are preferred by pyralids (tubes are between 5 and 10 mm long and 3 mm in diameter). These insect families benefit from inhabiting the tufa by the availability of construction materials of their cases and the necessary space for their development.

  11. [Key to chironomid pupal exuviae (Diptera: Chironomidae) of tropical high Andean streams].

    Science.gov (United States)

    Pratt, Narcís; González-Trujillo, Juan David; Ospina-Torres, Rodulfo

    2014-12-01

    The Chironomidae is a cosmopolitan family of Nematoceran flies with more than 20,000 species described. However the diversity of genera and species of the family in the Andean region beyond the 2,000 m.a.s.l are scarcely known. We conducted faunal surveys and biomonitoring research in different streams of Colombia, Ecuador and Peru from May 2005 to October 2011. Based on specimens collections, a taxonomic key was developed to identify pupae and pupal exuviae of 46 genera of midges (Diptera, Chironomidae) collected from streams at high altitude areas on the Andean tropical mountains. We included illustrations and brief taxonomic descriptions for all genera, of which several ones have not yet been formally described; in this latter case we used the nomenclature of Roback & Coffman (1983). For two genera, Cricotopus and Genus 1, keys to the most com- mon morphospecies were provided. Results showed that in this area the chironomid assemblages are dominated by the members of the subfamily Orthocladiinae (22 genera) followed by the Chironominae (13). Six genera of Tanypodinae were identified, while only three and two genera were present from subfamilies Podonominae and Diamesinae. This key may be very useful for both studies about drift in streams, and for biomonitoring purposes.

  12. Induction of mouthpart deformities in chironomid larvae exposed to contaminated sediments

    Energy Technology Data Exchange (ETDEWEB)

    Di Veroli, Alessandra [Dipartimento di Biologia Cellulare e Ambientale, Universita degli Studi di Perugia, Via Elce Di Sotto, 06123 Perugia (Italy); Goretti, Enzo [Dipartimento di Biologia Cellulare e Ambientale, Universita degli Studi di Perugia, Via Elce Di Sotto, 06123 Perugia (Italy); Paumen, Miriam Leon; Kraak, Michiel H.S.; Admiraal, Wim [Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Sciencepark 904, 1098 XH Amsterdam (Netherlands)

    2012-07-15

    The aim of the present study was to improve the cause-effect relationship between toxicant exposure and chironomid mouthpart deformities, by linking induction of mouthpart deformities to contaminated field sediments, metal mixtures and a mutagenic polycyclic aromatic compound metabolite (acridone). Mouthpart deformities in Chironomus riparius larvae were induced by both the heavy metal mixture and by acridone. A clear correlation between metal concentrations in the sediment and deformities incidence was only observed when the contaminated field sediments were left out of the analysis, probably because these natural sediments contained other toxic compounds, which could be responsible for a higher incidence of deformities than predicted by the measured metal concentrations only. The present study clearly improved the cause-effect relationship between toxicant exposure and the induction of mouthpart deformities. It is concluded that the incidence of mouthpart deformities may better reflect the potential toxicity of contaminated sediments than chemical analysis. - Highlights: Black-Right-Pointing-Pointer We tested the induction of deformities in C. riparius in laboratory toxicity experiments. Black-Right-Pointing-Pointer We used field sediments and spiked sediments with heavy metals and mutagenic PAC. Black-Right-Pointing-Pointer Mouthpart deformities were induced both by heavy metal mixtures and by acridone. Black-Right-Pointing-Pointer A correlation between metal concentrations in the sediment and deformities was found. Black-Right-Pointing-Pointer Mouthpart deformities better reflect the toxicity of sediments than chemical analysis. - Mouthpart deformities of Chironomus riparius larvae better reflect the toxicity of sediments than chemical analysis.

  13. Raising the bar (6)

    NARCIS (Netherlands)

    Elhorst, Paul; Abreu, Maria; Amaral, Pedro; Bhattacharjee, Arnab; Corrado, Luisa; Doran, Justin; Fingleton, Bernard; Fuerst, Franz; Garretsen, Harry; Igliori, Danilo; Le Gallo, Julie; McCann, Philip; Monastiriotis, Vassilis; Quatraro, Francesco; Yu, Jihai

    2017-01-01

    Raising the bar (6). Spatial Economic Analysis. This editorial summarizes and comments on the papers published in issue 12(4) so as to raise the bar in applied spatial economic research and highlight new trends. The first paper addresses the question of whether 'jobs follow people' or 'people follow

  14. Raised intracranial pressure

    African Journals Online (AJOL)

    is article presents an approach to raised intracranial pressure (ICP) constructed in a question-answer fashion. ..... Given that raised ICP is a serious and potentially life-threatening emergency, fast and reliable referral and transfer mechanisms should be established to ensure patients with this condition are effectively treated.

  15. Raising Confident Kids

    Science.gov (United States)

    ... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body ... Videos for Educators Search English Español Raising Confident Kids KidsHealth / For Parents / Raising Confident Kids What's in ...

  16. Medical Students Raising Concerns.

    Science.gov (United States)

    Druce, Maralyn R; Hickey, Andrea; Warrens, Anthony N; Westwood, Olwyn M R

    2016-09-16

    After a number of high-profile incidents and national reports, it has become clear that all health professionals and all medical students must be able to raise concerns about a colleague's behavior if this behavior puts patients, colleagues, or themselves at risk.Detailed evidence from medical students about their confidence to raise concerns is limited, together with examples of barriers, which impair their ability to do so. We describe a questionnaire survey of medical students in a single-center, examining self-reported confidence about raising concerns in a number of possible scenarios. Thematic analysis was applied to comments about barriers identified.Although 80% of respondents felt confident to report a patient safety issue, students were less confident around issues of probity, attitude, and conduct. This needs to be addressed to create clear mechanisms to raise concerns, as well as support for students during the process.

  17. Raising the Titanic.

    Science.gov (United States)

    Baker, Romona

    1990-01-01

    Described is an activity in which groups of students investigate engineering principles by writing a feasibility study to raise the luxury liner, Titanic. The problem statement and directions, and suggestions for problem solutions are included. (CW)

  18. Raising the bar (7)

    NARCIS (Netherlands)

    Elhorst, Paul; Abreu, Maria; Amaral, Pedro; Bhattacharjee, Arnab; Corrado, Luisa; Doran, Justin; Fingleton, Bernard; Fuerst, Franz; Garretsen, Harry; Igliori, Danilo; Gallo, Julie Le; McCann, Philip; Monastiriotis, Vassilis; Quatraro, Francesco; Yu, Jihai

    2018-01-01

    This editorial summarises the papers published in issue 13.1 so as to raise the bar in applied spatial economic research and highlight new trends. The first paper adopts a scale neutral approach to investigate the spatial mechanisms that cause regional innovation and growth. The second paper claims

  19. Raising the Bar (3)

    NARCIS (Netherlands)

    Elhorst, Paul; Abreu, M.; Amaral, P.; Bhattacharjee, A.; Corrado, L.; Fingleton, B.; Fuerst, F.; Garretsen, H.; Igliori, D.; Le Gallo, J.; McCann, P.; Monastiriotis, V.; Pryce, G.; Yu, J.

    This editorial summarizes and comments on the papers published in issue 11(3) so as to raise the bar in applied spatial economic research and highlight new trends. The first paper proposes spatial and a-spatial indicators to describe the networks of airline companies around the world. The second

  20. The effect of {sup 210}Pb and stable lead on the induction of mouthpart deformities in chironomid larvae

    Energy Technology Data Exchange (ETDEWEB)

    Bird, G A; Schwartz, W J; Hoffman, D [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1995-07-01

    To determine whether mouthpart deformities in chironomid larvae from Port Hope Harbour, Ontario, are the result of exposure to ionizing radiation or heavy metals in the sediment, Chironomus tentans larvae were exposed in the laboratory to concentrations of {sup 210}Pb and stable lead representative of contaminant levels in the harbour. Exposure to 100, 1000, and 2000 Bq {sup 210}Pb{center_dot}g{sup -1} dry sediment had no effect on the survival, growth of the larvae or frequency of deformities. Likewise, exposure to 0.5 and 5.0 mg lead{center_dot}g{sup -1} dry sediment had no effect on the larvae, but exposure to 35.0 mg lead{center_dot}g{sup -1} dry sediment resulted in 100% mortality of the larvae. These results indicate that the observed mouthpart deformities in chironomid larvae in Port Hope Harbour are not the result of radiation exposure. They also indicate that heavy metals (lead) may be having an impact on the population. (author). 28 refs., 9 tabs., 4 figs.

  1. The effect of 210Pb and stable lead on the induction of mouthpart deformities in chironomid larvae

    International Nuclear Information System (INIS)

    Bird, G.A.; Schwartz, W.J.; Hoffman, D.

    1995-07-01

    To determine whether mouthpart deformities in chironomid larvae from Port Hope Harbour, Ontario, are the result of exposure to ionizing radiation or heavy metals in the sediment, Chironomus tentans larvae were exposed in the laboratory to concentrations of 210 Pb and stable lead representative of contaminant levels in the harbour. Exposure to 100, 1000, and 2000 Bq 210 Pb·g -1 dry sediment had no effect on the survival, growth of the larvae or frequency of deformities. Likewise, exposure to 0.5 and 5.0 mg lead·g -1 dry sediment had no effect on the larvae, but exposure to 35.0 mg lead·g -1 dry sediment resulted in 100% mortality of the larvae. These results indicate that the observed mouthpart deformities in chironomid larvae in Port Hope Harbour are not the result of radiation exposure. They also indicate that heavy metals (lead) may be having an impact on the population. (author). 28 refs., 9 tabs., 4 figs

  2. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a ...

  3. Larval outbreaks in West Greenland

    DEFF Research Database (Denmark)

    Lund, Magnus; Raundrup, Katrine; Westergaard-Nielsen, Andreas

    2017-01-01

    effects of a larval outbreak in 2011 on vegetation productivity and CO2 exchange. We estimate a decreased carbon (C) sink strength in the order of 118–143 g C m−2, corresponding to 1210–1470 tonnes C at the Kobbefjord catchment scale. The decreased C sink was, however, counteracted the following years...

  4. Kauri seeds and larval somersaults

    DEFF Research Database (Denmark)

    Dupont, Steen Thorleif

    2012-01-01

    The trunk morphology of the larvae of the kauri pine (Agathis) seed infesting moth Agathiphaga is described using conventional, polarization, and scanning electron microscopy. The pine seed chamber formed by the larva is also described and commented on. The simple larval chaetotaxy includes more ...

  5. Production dynamics and life cycle of dominant chironomids (diptera, chironomidae) in a subtropical stream in China: adaptation to variable flow conditions in summer and autumn

    Science.gov (United States)

    Yan, Yunjun; Li, Xiaoyu

    2007-07-01

    The production dynamics and trophic basis of 7 dominant species of chironomids were investigated in the area of a second-order river of the Hanjiang River basin, in central China from June 2003 to June 2004. The results showed that Tvetenia discoloripes was by far the most abundant chironomid, dominating the overall standing stock of the taxa. In terms of lif ecycle, Chaetocladius sp., Eukiefferiella potthasti and T. discoloripes developed 1 generation a year, whereas Microtendipes sp. and Pagastia sp. developed two, while Pentaneura sp. and Polypedilum sp. developed three. T. discoloripes was the most productive chironomid with 120.305 8 g/m2. a, Pentaneura sp. and E. potthasti had relatively high production values of >17 g/m2.a, and the rest were 0.5), especially for filter-collectors Microtendipes sp., Chaetocladius sp., Chaetocladius sp., T. discoloripes and Pagastia sp. All species except Pentaneura sp. consumed a large portion of amorphous detritus, constituting more than 90% of their diets, and contributing nearly 90% to their secondary production. All the 7 chironomids represent obvious adaptation to local highly variable climate in summer and autumn in life cycle pattern, production dynamics, and food type.

  6. Long-term patterns of chironomid assemblages in a high elevation stream/lake network (Switzerland – Implications to global change

    Directory of Open Access Journals (Sweden)

    Brigitte Lods-Crozet

    2012-10-01

    Full Text Available A long-term monitoring program was initiated in 2002 on running and standing waters in a high elevation cirque landscape (Macun in the Swiss National Park. The region comprises contrasting basins with different water sources, a glacier-fed basin and two precipitation-fed basins. Sampling of 26 permanent and temporary ponds (or small lakes and of interconnecting streams (10 sites was conducted from 2002 to 2010. Pond macroinvertebrate assemblages were dominated by chironomids with 42 taxa. The Orthocladiinae were the dominant subfamily in richness and abundance with 22 taxa. The greatest diversity was found in ponds located in the south and outlet basins. The inter-year variability for the same pond is high, but no clear temporal trend was noticed in ponds frequently monitored ponds. The Orthocladiinae subfamily was also the richest in the stream sites where 33 taxa were collected. The north and south basins were separated on the basis of chironomid assemblages. The chironomid assemblages in the stream network shows a temporal trend from 2002 but it cannot be linked to any clear change at the community structure level. The higher richness and abundance in stream sites and ponds of the south basin could be related to a greater heterogeneity in water physico-chemistry and substrata, and by the presence of Bryophyta. The understanding of the environmental factors that influence faunal assemblages is crucial for the protection of this sensitive alpine pond network where a relatively high overall regional diversity (49 taxa is detected. From the literature, temperature is recognized as the driving force on changes in chironomid assemblages in alpine systems. Our results support the use of chironomids as flagship indicators in the assessment of climatic change in alpine landscapes.doi: 10.5324/fn.v31i0.1361.Published online: 17 October 2012.

  7. First feeding of larval herring

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter; Støttrup, Josianne

    1985-01-01

    The transition period from endogenous to exogenous feeding by larval herring was investigated in the laboratory for four herring stocks in order to evaluate the chances of survival at the time of fiest feeding. Observations on larval activity, feeding and growth were related to amount of yolk......, visual experience with potential prey organisms prior to first feeding and prey density. Herring larvae did not initiate exogenous feeding until around the time of yolk resorption. The timing of first feeding was not influenced by prior exposure to potential prey organisms during the yolk sac stage....... In the light of these observations, the ecological significance of the yolk sac stage is discussed. Initiation of exogenous feeding was delayed by 1-4 days at a low (7.5 nauplii .cntdot. l-1) compared to a high (120 nauplii .cntdot. l-1) prey density, but even at prey densities corresponding to the lower end...

  8. 'Peer pressure' in larval Drosophila?

    Science.gov (United States)

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-06-06

    Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on 'peer pressure', that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila. © 2014. Published by The Company of Biologists Ltd.

  9. Distracted Driving Raises Crash Risk

    Science.gov (United States)

    ... this issue Health Capsule Distracted Driving Raises Crash Risk En español Send us your comments Video technology ... distracted driving, especially among new drivers, raises the risk for car crashes and near crashes. The study ...

  10. Macroeconomic Conditions and Capital Raising

    OpenAIRE

    Isil Erel; Brandon Julio; Woojin Kim; Michael S. Weisbach

    2011-01-01

    Do macroeconomic conditions affect firms' abilities to raise capital? If so, how do they affect the manner in which the capital is raised? We address these questions using a large sample of publicly-traded debt issues, seasoned equity offers, bank loans and private placements of equity and debt. Our results suggest that a borrower's credit quality significantly affects its ability to raise capital during macroeconomic downturns. For noninvestment-grade borrowers, capital raising tends to be p...

  11. Domestic Larval Control Practices and Malaria Prevalence among Under-Five Children in Burkina Faso.

    Directory of Open Access Journals (Sweden)

    Souleymane Diabaté

    Full Text Available Larval source management has contributed to malaria decline over the past years. However, little is known about the impact of larval control practices undertaken at the household level on malaria transmission.The study was conducted in Kaya health district after the 2010 mass distribution of insecticide treated-nets and the initiation of malaria awareness campaigns in Burkina Faso. The aim was to (i estimate the level of domestic larval control practices (cleaning of the house and its surroundings, eradication of larval sources, and elimination of hollow objects that might collect water; (ii identify key determinants; and (iii explore the structural relationships between these practices, participation in awareness-raising activities and mothers' knowledge/attitudes/practices, and malaria prevalence among under-five children.Overall, 2004 households were surveyed and 1,705 under-five children were examined. Half of the mothers undertook at least one action to control larval proliferation. Mothers who had gone to school had better knowledge about malaria and were more likely to undertake domestic larval control practices. Living in highly exposed rural areas significantly decreased the odds of undertaking larval control actions. Mothers' participation in malaria information sessions increased the adoption of vector control actions and bednet use. Malaria prevalence was statistically lower among children in households where mothers had undertaken at least one vector control action or used bed-nets. There was a 0.16 standard deviation decrease in malaria prevalence for every standard deviation increase in vector control practices. The effect of bednet use on malaria prevalence was of the same magnitude.Cleaning the house and its surroundings, eradicating breeding sites, and eliminating hollow objects that might collect water play a substantial role in preventing malaria among under-five. There is a need for national malaria control programs to

  12. Ocean acidification alters temperature and salinity preferences in larval fish.

    Science.gov (United States)

    Pistevos, Jennifer C A; Nagelkerken, Ivan; Rossi, Tullio; Connell, Sean D

    2017-02-01

    Ocean acidification alters the way in which animals perceive and respond to their world by affecting a variety of senses such as audition, olfaction, vision and pH sensing. Marine species rely on other senses as well, but we know little of how these might be affected by ocean acidification. We tested whether ocean acidification can alter the preference for physicochemical cues used for dispersal between ocean and estuarine environments. We experimentally assessed the behavioural response of a larval fish (Lates calcarifer) to elevated temperature and reduced salinity, including estuarine water of multiple cues for detecting settlement habitat. Larval fish raised under elevated CO 2 concentrations were attracted by warmer water, but temperature had no effect on fish raised in contemporary CO 2 concentrations. In contrast, contemporary larvae were deterred by lower salinity water, where CO 2 -treated fish showed no such response. Natural estuarine water-of higher temperature, lower salinity, and containing estuarine olfactory cues-was only preferred by fish treated under forecasted high CO 2 conditions. We show for the first time that attraction by larval fish towards physicochemical cues can be altered by ocean acidification. Such alterations to perception and evaluation of environmental cues during the critical process of dispersal can potentially have implications for ensuing recruitment and population replenishment. Our study not only shows that freshwater species that spend part of their life cycle in the ocean might also be affected by ocean acidification, but that behavioural responses towards key physicochemical cues can also be negated through elevated CO 2 from human emissions.

  13. Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model

    Science.gov (United States)

    Matthews-Bird, Frazer; Brooks, Stephen J.; Holden, Philip B.; Montoya, Encarni; Gosling, William D.

    2016-06-01

    Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150 m above sea level (a.s.l) to 4655 m a.s.l, between 0-17° S and 64-78° W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9 % of the variance (λ1/λ2 = 1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2jack = 0.890; RMSEPjack = 2.404 °C, RMSEP - root mean squared error of prediction; mean biasjack = -0.017 °C; max biasjack = 4.665 °C). The Bayesian method produced a model with R2jack = 0.909, RMSEPjack = 2.373 °C, mean biasjack = 0.598 °C, and max biasjack = 3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000-2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca. -7 ± 2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca. -3 ± 3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only

  14. A chironomid-based record of temperature variability during the past 4000 years in northern China and its possible societal implications

    Science.gov (United States)

    Wang, Haipeng; Chen, Jianhui; Zhang, Shengda; Zhang, David D.; Wang, Zongli; Xu, Qinghai; Chen, Shengqian; Wang, Shijin; Kang, Shichang; Chen, Fahu

    2018-03-01

    Long-term, high-resolution temperature records which combine an unambiguous proxy and precise dating are rare in China. In addition, the societal implications of past temperature change on a regional scale have not been sufficiently assessed. Here, based on the modern relationship between chironomids and temperature, we use fossil chironomid assemblages in a precisely dated sediment core from Gonghai Lake to explore temperature variability during the past 4000 years in northern China. Subsequently, we address the possible regional societal implications of temperature change through a statistical analysis of the occurrence of wars. Our results show the following. (1) The mean annual temperature (TANN) was relatively high during 4000-2700 cal yr BP, decreased gradually during 2700-1270 cal yr BP and then fluctuated during the last 1270 years. (2) A cold event in the Period of Disunity, the Sui-Tang Warm Period (STWP), the Medieval Warm Period (MWP) and the Little Ice Age (LIA) can all be recognized in the paleotemperature record, as well as in many other temperature reconstructions in China. This suggests that our chironomid-inferred temperature record for the Gonghai Lake region is representative. (3) Local wars in Shanxi Province, documented in the historical literature during the past 2700 years, are statistically significantly correlated with changes in temperature, and the relationship is a good example of the potential societal implications of temperature change on a regional scale.

  15. Models of prey capture in larval fish

    NARCIS (Netherlands)

    Drost, M.R.

    1986-01-01

    The food uptake of larval carp and pike is described from high speed movies with synchronous lateral and ventral views.

    During prey intake by larval fishes the velocities of the created suction flow are high relative to their own size: 0.3 m/s for carp larvae of 6

  16. [Canine peritoneal larval cestodosis caused by Mesocestoides spp. larval stages].

    Science.gov (United States)

    Häußler, T C; Peppler, C; Schmitz, S; Bauer, C; Hirzmann, J; Kramer, M

    2016-01-01

    In a female dog with unspecific clinical symptoms, sonography detected a hyperechoic mass in the middle abdomen and blood analysis a middle grade systemic inflammatory reaction. Laparotomy revealed a peritoneal larval cestodosis (PLC). The diagnosis of an infection with tetrathyridia of Mesocestoides spp. was confirmed by parasitological examination and molecularbiological analysis. Reduction of the intra-abdominal parasitic load as well as a high dose administration of fenbendazole over 3 months led to a successful treatment which could be documented sonographically and by decreased concentrations of C-reactive protein (CRP). Seven months after discontinuation of fenbendazole administration, PLC recurred, pre-empted by an elevation of serum CRP values. According to the literature a life-long fenbendazole treatment was initiated. In cases of unclear chronic granulomatous inflammations in the abdominal cavity in dogs, PLC should be considered. CRP concentration and sonographic examinations are suitable to control for treatment success and a possibly occurring relapse.

  17. Legacy of road salt: Apparent positive larval effects counteracted by negative postmetamorphic effects in wood frogs.

    Science.gov (United States)

    Dananay, Kacey L; Krynak, Katherine L; Krynak, Timothy J; Benard, Michael F

    2015-10-01

    Road salt runoff has potentially large effects on wetland communities, but is typically investigated in short-term laboratory trials. The authors investigated effects of road salt contamination on wood frogs (Rana sylvatica) by combining a field survey with 2 separate experiments. The field survey tested whether wood frog larval traits were associated with road salt contamination in natural wetlands. As conductivity increased, wood frog larvae were less abundant, but those found were larger. In the first experiment of the present study, the authors raised larvae in outdoor artificial ponds under 4 salt concentrations and measured larval vital rates, algal biomass, and zooplankton abundance. Salt significantly increased larval growth, algal biomass, and decreased zooplankton abundance. In the second experiment, the authors raised larvae to metamorphosis in the presence and absence of salt contamination and followed resulting juvenile frogs in terrestrial pens at high and low densities. Exposure to road salt as larvae caused juvenile frogs to have greater mortality in low-density terrestrial environments, possibly because of altered energy allocation, changes in behavior, or reduced immune defenses. The present study suggests that low concentrations of road salt can have positive effects on larval growth yet negative effects on juvenile survival. These results emphasize the importance of testing for effects of contaminants acting through food webs and across multiple life stages as well as the potential for population-level consequences in natural environments. © 2015 SETAC.

  18. Raising Awareness in Science Education for Women (RAISE-W)

    Science.gov (United States)

    Faherty, Jacqueline K.; Holford, M.

    2014-01-01

    Raising Awareness in Science Education for Women (RAISE-W) is a 501c non profit corporation whose mission is to aid in increasing and retaining the number of women - especially underrepresented females - engaged in scientific teaching and research. Initiated by a Protein Chemist and an Astronomer, our ultimate goal has been to develop informational tools and create innovative outreach programs for women across all STEM fields. At present RAISE-W is recruiting women at the undergraduate, graduate, and early career stages to participate in a unique, 1-year, executive coaching program modeled after those used in the business sector.

  19. Do effects of mercury in larval amphibians persist after metamorphosis?

    Science.gov (United States)

    Todd, Brian D; Willson, John D; Bergeron, Christine M; Hopkins, William A

    2012-01-01

    Despite widespread concern about the role of environmental contaminants in global amphibian declines, and evidence that post-metamorphic life stages contribute disproportionately to amphibian population dynamics, most studies in amphibian ecotoxicology focus on larval life stages. Studies that focus solely on early life stages may miss important effects of contaminant exposure, such as latent effects that manifest some time after previous exposure. Moreover, it is often assumed that effects observed in amphibian larvae will persist to affect survival or reproduction later in life. We used terrestrial enclosures to determine whether exposure to mercury (Hg) through maternal transfer and/or larval diet had any adverse effects in post-metamorphic American toads (Bufo americanus). We found a 5% difference in size at metamorphosis that was attributed to maternal Hg exposure persisted for 1 year in the terrestrial environment, resulting in a 7% difference at the conclusion of the study. Although patterns of survival differed among treatments through time, we found no overall difference in survival after 1 year. We also found no evidence of emergent latent effects in the terrestrial toads that could be attributed to earlier exposure. Our results indicate that adverse effects of maternal Hg exposure that were observed in larval amphibians may persist to affect later terrestrial life stages but that no novel adverse effects developed when animals were raised in a semi-natural environment. Moreover, we found no evidence of persistent effects of dietary Hg exposure in larvae, highlighting a need for greater focus on maternal effects in amphibian ecotoxicology. Finally, we suggest an increase in the use of longitudinal studies to better understand contaminant impacts to amphibian populations via effects in both aquatic and terrestrial life stages.

  20. Density and temperature dependent feeding rates in an established and an alien freshwater gammarid fed on chironomid larvae

    Directory of Open Access Journals (Sweden)

    Dieter WALOSZEK

    2011-02-01

    Full Text Available We compared feeding rates of the well-established, non-invasive amphipod Gammarus roeselii with those of the invasive Dikerogammarus villosus at different prey densities and different temperatures in laboratory experiments using chironomid larvae as prey. Feeding rates were very variable in both species but higher in the invader species than in the well-established non-invasive species. These results were age independent. At high temperature (18-20 °C and high prey density (≥1000 prey m-2 one large adult D. villosus consumed 6-9 prey day-1 on average while one G. roeselii consumed 4-7 prey d-1 and one smaller D. villosus of a length of 8-10 mm consumed 2-5 prey d-1 while one G. roeselii of the same length consumed 3 prey d-1. Predation rate decreased considerably from high (18-20 °C to low temperature (3±2 °C, from 9 to 4 prey predator-1 d-1 in D. villosus and from 7.5 to 2.5 prey predator-1 d-1 in G. roeselii. We conclude that both gammarids consumed a biomass in the range of 1/2 to 1/3 to their own biomass and that low predation/feeding rate at low temperature could be a reason why, in some places, indigenous gammarids can re-colonize their former habitats for a short period of time in cold winter and early spring in spite of the presence of the invasive. We further conclude that differences in weight between the species in particular in the experiments with adults can have influenced feeding rates; possibly differences in weight- specific feeding rates are small.

  1. Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds.

    Science.gov (United States)

    Eggleston, David B; Lillis, Ashlee; Bohnenstiehl, DelWayne R

    2016-01-01

    We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites.

  2. Raising Public Awareness of Mathematics

    CERN Document Server

    Behrends, Ehrhard; Rodrigues, José Francisco

    2012-01-01

    This collective book aims to encourage and inspire actions directed towards raising public awareness of the importance of mathematical sciences for our contemporary society in a cultural and historical perspective. Mathematical societies, in Europe and around the world, can find ideas, blueprints and suggestions for activities - including concerted actions with other international organizations - directed towards raising public awareness of science, technology and other fields where mathematics plays a strong role. The material is divided into four parts: * National experiences * Exhibitions /

  3. Raising HDL cholesterol in women

    Directory of Open Access Journals (Sweden)

    Danny J Eapen

    2009-11-01

    Full Text Available Danny J Eapen1, Girish L Kalra1, Luay Rifai1, Christina A Eapen2, Nadya Merchant1, Bobby V Khan11Emory University School of Medicine, Atlanta, GA, USA; 2University of South Florida School of Medicine, Tampa, FL, USAAbstract: High-density lipoprotein cholesterol (HDL-C concentration is essential in the determination of coronary heart disease (CHD risk in women. This is especially true in the postmenopausal state, where lipid profiles and CHD risk mimic that of age-matched men. Thus, interventions designed to reduce CHD risk by raising HDL-C levels may have particular significance during the transition to menopause. This review discusses HDL-C-raising therapies and the role of HDL in the primary prevention of CHD in women. Lifestyle-based interventions such as dietary change, aerobic exercise regimens, and smoking cessation are initial steps that are effective in raising HDL-C, and available data suggest women respond similarly to men with these interventions. When combined with pharmacotherapy, the effects of these lifestyle alterations are further amplified. Though studies demonstrating gender-specific differences in therapy are limited, niacin continues to be the most effective agent in raising HDL-C levels, especially when used in combination with fibrate or statin therapy. Emerging treatments such as HDL mimetic therapy show much promise in further raising HDL-C levels and improving cardiovascular outcomes.Keywords: high-density lipoprotein, HDL, women, cholesterol, heart disease

  4. Anopheline larval habitats seasonality and species distribution: a prerequisite for effective targeted larval habitats control programmes.

    Directory of Open Access Journals (Sweden)

    Eliningaya J Kweka

    Full Text Available Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya.A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60% and An.arabiensis (18.34%, the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024 and An. arabiensis (P = 0.002 larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001, grass cover (P≤0.001, while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001. The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001 when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002. When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines.These findings suggest that implementation of effective larval control programme should be targeted with larval

  5. Raising the Bar for Teaching

    Science.gov (United States)

    Mehta, Jal; Doctor, Joe

    2013-01-01

    The past year has seen the emergence of a broad consensus on raising the standards for entering the teaching profession. The NEA, AFT, and Council of Chief State School Officers all have said they want higher entry standards. Such an exam would be modeled after other professions and is a potential game changer. If sufficiently rigorous, the exam…

  6. Fund Raising: An International Feast.

    Science.gov (United States)

    Babb, Valorie; Marshall, Gene

    The procedure for planning an international dinner to raise funds and publicize foreign language study is described. The project, which netted several hundred dollars for a high school in North Dakota, involves careful planning over a period of months. Publicity and facilities are discussed, and the various culinary and other jobs to be…

  7. Rehydration of forensically important larval Diptera specimens.

    Science.gov (United States)

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  8. Soundscapes and Larval Settlement: Characterizing the Stimulus from a Larval Perspective.

    Science.gov (United States)

    Lillis, Ashlee; Eggleston, David B; Bohnenstiehl, DelWayne R

    2016-01-01

    There is growing evidence that underwater sounds serve as a cue for the larvae of marine organisms to locate suitable settlement habitats; however, the relevant spatiotemporal scales of variability in habitat-related sounds and how this variation scales with larval settlement processes remain largely uncharacterized, particularly in estuarine habitats. Here, we provide an overview of the approaches we have developed to characterize an estuarine soundscape as it relates to larval processes, and a conceptual framework is provided for how habitat-related sounds may influence larval settlement, using oyster reef soundscapes as an example.

  9. Genetic diversity, classification and comparative study on the larval ...

    African Journals Online (AJOL)

    Genetic diversity, classification and comparative study on the larval phenotypic ... B. mori showed different performance based on larval phenotypic data. The analysis of variance regarding the studied traits showed that different strains have ...

  10. Romania's flag raised at CERN

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    A ceremony was held for the raising of the Romanian flag alongside the flags of CERN’s 21 other Member States.   The Romanian flag is raised alongside the flags of CERN’s other Member States, in the presence of the Romanian President, CERN’s Director-General, the President of the CERN Council and a large Romanian delegation. (Image: Maximilien Brice/ Sophia Bennett/CERN) On Monday, 5 September, the Romanian flag was raised in front of CERN for the first time, marking the country’s accession to Membership of the Organization. The blue, yellow and red flag joined those of the other 21 Member States of CERN in a ceremony attended by the President of Romania, Klaus Iohannis, the Romanian Minister for Education and Scientific Research, Mircea Dumitru, and several other members of the President’s office, the government and academia in Romania. The country officially became a CERN Member State on 17 July 2016, after 25 years of collaboration between the...

  11. Biophysical models of larval dispersal in the Benguela Current ...

    African Journals Online (AJOL)

    We synthesise and update results from the suite of biophysical, larval-dispersal models developed in the Benguela Current ecosystem. Biophysical models of larval dispersal use outputs of physical hydrodynamic models as inputs to individual-based models in which biological processes acting during the larval life are ...

  12. Effects of an Experimental Enrichment of Instream Habitat Heterogeneity on the Stream Bed Morphology and Chironomid Community of a Straightened Section in a Sandy Lowland Stream

    Science.gov (United States)

    Spänhoff, Bernd; Riss, Wolfgang; Jäkel, Paul; Dakkak, Nadja; Meyer, Elisabeth I.

    2006-02-01

    A straightened stream stretch with poor habitat heterogeneity was divided into a “control” section with a low amount of submerged woody debris and an experimentally “wood-enriched” downstream section to study the effect of enhanced habitat diversity on the benthic invertebrate community. The downstream section was enriched by fixing 25 wood packages constructed from 9-10 branches on the stream bottom. Succession processes occurring in the two stream sections were compared by chironomid exuviae drift from July to November 2000 and from April to August 2001. During the first sampling period, more drifting chironomid exuviae (medians of control vs. wood-enriched: 446 vs. 331, no significant difference) and total number of taxa (44 vs. 36, Wilcoxon signed-rank test P = 0.019) were recorded for the control section. Although species compositions of both stream sections were highly similar (Sørensen index: 0.83) the diversity in the wood-enriched section was distinctly lower compared to the control section (Shannon-Weaver index: 1.19 vs. 1.50). During the second sampling period, exuviae numbers remained higher in the control section (median: 326 vs. 166), but total numbers of taxa were nearly equal (51 vs. 49), as well as species diversity (Shannon-Weaver index: 1.67 vs. 1.64). The lower chironomid diversity observed during the first sampling period coincided with a gradual but significant change of the streambed morphology in the wood-enriched section. There, the initially more U-shaped profile (V/U = 0.81 ± 0.37) had turned into a pronounced V shape (V/U = 1.14 ± 0.21), whereas the control section retained its unaltered U shape (V/U = 0.62-0.75). This small-scale study on experimental of woody debris in sandy lowland streams showed that the negative impact of increased hydraulic disturbance of the existing streambed more than outweighed any positive impact resulting from the increase in woody debris.

  13. Williston Reservoir raising - environmental overview

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    This preliminary environmental overview report was prepared by B.C. Hydro in June 1987 and revised in July 1988 as an initial assessment of a possible 1.5 m (5 ft.) raise in the Williston Reservoir maximum normal level. The enviromental overview study and the associated engineering and property studies were undertaken to provide information for a decision on whether to initiate more detailed studies. Overview studies are based mainly on available reports, mapping and field data, supplemented by limited site reconnaissance and, in this case, input from key agencies and groups. The lack of adequate mapping of areas which could be affected by reservoir raising did not permit definitive conclusion to be reached. This mapping will be done over the next year to complete the overview assessment. This document covers the impact assessment of socio-economic factors, forestry, reservoir clearing, heritage, recreation, aquatic resources, and wilflife. Further studies in each of these areas are also included. 54 refs., 11 figs., 8 tabs.

  14. Effect of massing on larval growth rate.

    Science.gov (United States)

    Johnson, Aidan P; Wallman, James F

    2014-08-01

    Estimation of minimum postmortem interval commonly relies on predicting the age of blowfly larvae based on their size and an estimate of the temperatures to which they have been exposed throughout their development. The majority of larval growth rate data have been developed using small larval masses in order to avoid excess heat generation. The current study collected growth rate data for larvae at different mass volumes, and assessed the temperature production of these masses, for two forensically important blow fly species, Chrysomya rufifacies and Calliphora vicina. The growth rate of larvae in a small mass, exposed to the higher temperatures equivalent to those experienced by large masses, was also assessed to determine if observed differences were due to the known temperature effects of maggot masses. The results showed that temperature production increased with increasing mass volume, with temperature increases of 11 °C observed in the large Ch. rufifacies masses and increases of 5 °C in the large C. vicina masses. Similarly, the growth rate of the larvae was affected by mass size. The larvae from small masses grown at the higher temperatures experienced by large masses displayed an initial delay in growth, but then grew at a similar rate to those larvae at a constant 23 °C. Since these larvae from masses of equivalent sizes displayed similar patterns of growth rate, despite differing temperatures, and these growth rates differed from larger masses exposed to the same temperatures, it can be concluded that larval growth rate within a mass may be affected by additional factors other than temperature. Overall, this study highlights the importance of understanding the role of massing in larval development and provides initial developmental data for mass sizes of two forensically important blowfly species commonly encountered in Australian forensic casework. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Granulomatous responses in larval taeniid infections.

    Science.gov (United States)

    Díaz, Á; Sagasti, C; Casaravilla, C

    2018-05-01

    Granulomas are responses to persistent nonliving bodies or pathogens, centrally featuring specialized macrophage forms called epithelioid and multinucleated giant cells. The larval stages of the cestode parasites of the Taeniidae family (Taenia, Echinococcus) develop for years in fixed tissue sites in mammals. In consequence, they are targets of granulomatous responses. The information on tissue responses to larval taeniids is fragmented among host and parasite species and scattered over many decades. We attempt to draw an integrated picture of these responses in solid tissues. The intensity of inflammation around live parasites spans a spectrum from minimal to high, parasite vitality correlating with low inflammation. The low end of the inflammatory spectrum features collagen capsules proximal to the parasites and moderate distal infiltration. The middle of the spectrum is dominated by classical granulomatous responses, whereas the high end features massive eosinophil invasions. Across the range of parasite species, much observational evidence suggests that eosinophils are highly effective at killing larval taeniids in solid tissues, before and during chronic granulomatous responses. The evidence available also suggests that these parasites are adapted to inhibit host granulomatous responses, in part through the exacerbation of host regulatory mechanisms including regulatory T cells and TGF-β. © 2018 John Wiley & Sons Ltd.

  16. Cloning of aquaporin-1 of the blue crab, Callinectes sapidus: its expression during the larval development in hyposalinity.

    Science.gov (United States)

    Chung, J Sook; Maurer, Leah; Bratcher, Meagan; Pitula, Joseph S; Ogburn, Matthew B

    2012-09-03

    Ontogenetic variation in salinity adaptation has been noted for the blue crab, Callinectes sapidus, which uses the export strategy for larval development: females migrate from the estuaries to the coast to spawn, larvae develop in the ocean, and postlarvae (megalopae) colonize estuarine areas. We hypothesized that C. sapidus larvae may be stenohaline and have limited osmoregulatory capacity which compromises their ability to survive in lower salinity waters. We tested this hypothesis using hatchery-raised larvae that were traceable to specific life stages. In addition, we aimed to understand the possible involvement of AQP-1 in salinity adaptation during larval development and during exposure to hyposalinity. A full-length cDNA sequence of aquaporin (GenBank JQ970426) was isolated from the hypodermis of the blue crab, C. sapidus, using PCR with degenerate primers and 5' and 3' RACE. The open reading frame of CasAQP-1 consists of 238 amino acids containing six helical structures and two NPA motifs for the water pore. The expression pattern of CasAQP-1 was ubiquitous in cDNAs from all tissues examined, although higher in the hepatopancreas, thoracic ganglia, abdominal muscle, and hypodermis and lower in the antennal gland, heart, hemocytes, ovary, eyestalk, brain, hindgut, Y-organs, and gill. Callinectes larvae differed in their capacity to molt in hyposalinity, as those at earlier stages from Zoea (Z) 1 to Z4 had lower molting rates than those from Z5 onwards, as compared to controls kept in 30 ppt water. No difference was found in the survival of larvae held at 15 and 30 ppt. CasAQP-1 expression differed with ontogeny during larval development, with significantly higher expression at Z1-2, compared to other larval stages. The exposure to 15 ppt affected larval-stage dependent CasAQP-1 expression which was significantly higher in Z2- 6 stages than the other larval stages. We report the ontogenetic variation in CasAQP-1 expression during the larval development

  17. Aedes larval indices and the occurrence of Dengue Haemorrhagic Fever in urban community of Thanlyin Township

    Directory of Open Access Journals (Sweden)

    Thae’ Zar Chi Bo

    2016-02-01

    Full Text Available A cross-sectional study was conducted in urban community of Thanlyin Township, Yangon Region during 2014 to determine Aedes larval indices and the occurrence of Dengue Haemorrhagic Fever (DHF within past one year. A total of 327 households and 1491 members were included in the study. Aedes larval indices detected in this study were 25.7% for house index, 15.5% for container index and 48.0% for Breteau index. The occurrence of DHF among households and family members were 2.1% (95% CI: 0.9%, 4.4% and 0.6% (95% CI: 0.3%, 1.1%, respectively. The occurrence was highest among 5 to 14 years age-group. No case was reported among persons with equal or more than 60 years of age. Mortality and case fatality rates were 0% during study period. Larval positivity among households was significantly related to sufficiency of family income and number of water container they have. Surveillance and control procedures for both DHF and vector should be intensified in urban area. Awareness and participation of the community in prevention and control of DHF should also be raised. Socioeconomic status as well as proper water supply and storage should be improved in urban area.

  18. Fish larval transport in the coastal waters through ecological modelling

    Digital Repository Service at National Institute of Oceanography (India)

    George, G.

    are as follows: (i) to find out the influence of environmental parameters on the biology of the given ecosystem (ii) to track larval transport and biological abundance in relation to environmental vari- ables (iii) to compare biological abundance and fish larval... include the following investigations: (i) analysis of satellite chlorophyll data along the southwest coastal waters of India to derive a biological calender for sardine (ii) tracking the larval survival and establish a link between food and sardine inter...

  19. Evaluating sampling strategies for larval cisco (Coregonus artedi)

    Science.gov (United States)

    Myers, J.T.; Stockwell, J.D.; Yule, D.L.; Black, J.A.

    2008-01-01

    To improve our ability to assess larval cisco (Coregonus artedi) populations in Lake Superior, we conducted a study to compare several sampling strategies. First, we compared density estimates of larval cisco concurrently captured in surface waters with a 2 x 1-m paired neuston net and a 0.5-m (diameter) conical net. Density estimates obtained from the two gear types were not significantly different, suggesting that the conical net is a reasonable alternative to the more cumbersome and costly neuston net. Next, we assessed the effect of tow pattern (sinusoidal versus straight tows) to examine if propeller wash affected larval density. We found no effect of propeller wash on the catchability of larval cisco. Given the availability of global positioning systems, we recommend sampling larval cisco using straight tows to simplify protocols and facilitate straightforward measurements of volume filtered. Finally, we investigated potential trends in larval cisco density estimates by sampling four time periods during the light period of a day at individual sites. Our results indicate no significant trends in larval density estimates during the day. We conclude estimates of larval cisco density across space are not confounded by time at a daily timescale. Well-designed, cost effective surveys of larval cisco abundance will help to further our understanding of this important Great Lakes forage species.

  20. Oribatid mite (Acari: Oribatida) and Chironomid (Diptera: Chironomidae) communities from a high-Andean cushion peatland in Peru (14°S) and their use for palaeoenvironmental reconstruction during the Nasca cultural period

    OpenAIRE

    Hense, Jonathan Boray

    2016-01-01

    The edaphic Oribatid mites and Chironomid larvae of five different successional stages of a high-Andean cushion peatland in southern Peru (14°S) were investigated. In total, 17 Oribatid mite taxa, belonging to eight families could be identified. Taxonomic remarks for the species found and an analysis of community structures are provided. The investigation shows significantly higher Oribatid mite densities in the early and medium successional stages in comparison to the successional climax eco...

  1. Quantitative summer temperature reconstruction derived from a combined biogenic Si and chironomid record from varved sediments of Lake Silvaplana (south-eastern Swiss Alps) back to AD 1177

    Science.gov (United States)

    Trachsel, M.; Grosjean, M.; Larocque-Tobler, I.; Schwikowski, M.; Blass, A.; Sturm, M.

    2010-09-01

    High-resolution quantitative temperature records are needed for placing the recent warming into the context of long-term natural climate variability. In this study we present a quantitative high-resolution (9-year) summer (June-August) temperature reconstruction back to AD 1177 for the south-eastern Swiss Alps. This region is a good predictor for summer temperatures in large parts of western and central Europe. Our reconstruction is based on a combination of the high-frequency component of annually resolved biogenic silica (bSi flux) data and the low-frequency component of decadal chironomid-inferred temperatures from annually laminated well dated sediments (varves) from proglacial Lake Silvaplana, eastern Swiss Alps. For the calibration (period AD 1760-1949) we assess systematically the effects of six different regression methods (Type I regressions: Inverse Regression IR, Inverse Prediction IP, Generalised Least Squares GLS; Type II regressions: Major Axis MA, Ranged Major Axis RMA and Standard Major Axis SMA) with regard to the predicted amplitude and the calibration statistics such as root-mean-square error of prediction (RMSEP), reduction of error (RE) and coefficient of efficiency (CE). We found a trade-off in the regression model choice between a good representation of the amplitude and good calibration statistics. The band-pass filtered bSi flux record is in close agreement both in the structure and the amplitude with two fully independent reconstructions spanning back to AD 1500 and AD 1177, respectively. All known pulses of negative volcanic forcing are represented as cold anomalies in the bSi flux record. Volcanic pulses combined with low solar activity (Spörer and Maunder Minimum) are seen as particularly cold episodes around AD 1460 and AD 1690. The combined chironomid and bSi flux temperature record (RMSEP = 0.57 °C) is in good agreement with the glacier history of the Alps. The warmest (AD 1190) and coldest decades (17th century; 1680-1700) of our

  2. Turbulence-enhanced prey encounter rates in larval fish : Effects of spatial scale, larval behaviour and size

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; MacKenzie, Brian

    1995-01-01

    Turbulent water motion has several effects on the feeding ecology of larval fish and other planktivorous predators. In this paper, we consider the appropriate spatial scales for estimating relative velocities between larval fish predators and their prey, and the effect that different choices of s...... in the range in which turbulent intensity has an overall positive effect on larval fish ingestion rate probability. However, experimental data to test the model predictions are lacking. We suggest that the model inputs require further empirical study....

  3. Adaptive locomotor behavior in larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2011-01-01

    In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish.

  4. Microhabitat influence on larval fish assemblages within ...

    Science.gov (United States)

    We examined larval and juvenile fish assemblage structure in relation to microhabitat variables within the St. Louis River estuary, a drowned river mouth of Lake Superior. Fish were sampled in vegetated beds throughout the estuary, across a gradient of vegetation types and densities (including disturbed, preserved and post-restoration sites). Canonical correspondence analysis, relating species abundances to environmental variables revealed that plant species richness, turbidity and aquatic plant cover were most influential in structuring assemblages. Results from this microhabitat analysis at this crucial life stage has potential to inform wetland restoration efforts within the St. Louis River and other Great Lake coastal wetlands. not applicable

  5. Larval Population Density Alters Adult Sleep in Wild-Type Drosophila melanogaster but Not in Amnesiac Mutant Flies

    Directory of Open Access Journals (Sweden)

    Michael W. Chi

    2014-08-01

    Full Text Available Sleep has many important biological functions, but how sleep is regulated remains poorly understood. In humans, social isolation and other stressors early in life can disrupt adult sleep. In fruit flies housed at different population densities during early adulthood, social enrichment was shown to increase subsequent sleep, but it is unknown if population density during early development can also influence adult sleep. To answer this question, we maintained Drosophila larvae at a range of population densities throughout larval development, kept them isolated during early adulthood, and then tested their sleep patterns. Our findings reveal that flies that had been isolated as larvae had more fragmented sleep than those that had been raised at higher population densities. This effect was more prominent in females than in males. Larval population density did not affect sleep in female flies that were mutant for amnesiac, which has been shown to be required for normal memory consolidation, adult sleep regulation, and brain development. In contrast, larval population density effects on sleep persisted in female flies lacking the olfactory receptor or83b, suggesting that olfactory signals are not required for the effects of larval population density on adult sleep. These findings show that population density during early development can alter sleep behavior in adulthood, suggesting that genetic and/or structural changes are induced by this developmental manipulation that persist through metamorphosis.

  6. Chironomid-based reconstructions of summer air temperature from lake deposits in Lyndon Stream, New Zealand spanning the MIS 3/2 transition

    Science.gov (United States)

    Woodward, C. A.; Shulmeister, J.

    2007-01-01

    We present chironomid-based temperature reconstructions from lake sediments deposited between ca 26,600 cal yr BP and 24,500 cal yr BP from Lyndon Stream, South Island, New Zealand. Summer (February mean) temperatures averaged 1 °C cooler, with a maximum inferred cooling of 3.7 °C. These estimates corroborate macrofossil and beetle-based temperature inferences from the same site and suggest climate amelioration (an interstadial) at this time. Other records from the New Zealand region also show a large degree of variability during the late Otiran glacial sequence (34,000-18,000 cal yr BP) including a phase of warming at the MIS 2/3 transition and a maximum cooling that did not occur until the global LGM (ca 20,000 cal yr BP). The very moderate cooling identified here at the MIS 2/3 transition confirms and enhances the long-standing discrepancy in New Zealand records between pollen and other proxies. Low abundances (<20%) of canopy tree pollen in records from late MIS 3 to the end of MIS 2 cannot be explained by the minor (<5 °C) cooling inferred from this and other studies unless other environmental parameters are considered. Further work is required to address this critical issue.

  7. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 85; Issue 3. Reduced larval feeding rate is a strong evolutionary correlate of rapid development in Drosophila melanogaster. M. Rajamani N. Raghavendra ... Keywords. life-history evolution; development time; larval feeding rate; competition; tradeoffs; Drosophila melanogaster.

  8. The larval development of the red mangrove crab Sesarma meinerti ...

    African Journals Online (AJOL)

    The larval stages of the red mangrove crab Sesarma meinerti de Man were reared in the laboratory. Larval development consists of five zoeal stages and one megalopa. Zoeal development lasts an average of 25 days at 25°C. The external morphology of larvae is described in detail and their relationship with larvae of.

  9. 50 CFR 14.23 - Live farm-raised fish and farm-raised fish eggs.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Live farm-raised fish and farm-raised fish eggs. 14.23 Section 14.23 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF... Exportation at Designated Ports § 14.23 Live farm-raised fish and farm-raised fish eggs. Live farm-raised fish...

  10. Elevated copper levels during larval development cause altered locomotor behavior in the adult carabid beetle Pterostichus cupreus L. (Coleoptera: Carbidae)

    DEFF Research Database (Denmark)

    Bayley, M; Baatrup, E; Heimbach, U

    1995-01-01

    behavior of adult Pterostichus cupreus carabid beetles was quantified after being raised on copper-contaminated food and soil during larval development. Copper was found to have an acute toxic effect measured in larval mortality, to cause a slight increase in the developmental period of males......It is generally believed that copper causes changes in carabid communities indirectly by reducing food availability, because these animals are frequently found to have only slightly elevated metal contents even close to pollution sources. Using computer-centered video tracking, the locomotor......, but not to effect the emergence weights of adults of either sex. This toxic effect on the larvae was preserved through pupation to the surviving adults, which were normal in size and appearance, but displayed a dramatically depressed locomotor behavior. Copper analysis of these adults revealed that copper levels...

  11. The Logic of the RAISE Specification Language

    DEFF Research Database (Denmark)

    George, Chris; Haxthausen, Anne Elisabeth

    2003-01-01

    This paper describes the logic of the RAISE Specification Language, RSL. It explains the particular logic chosen for RAISE, and motivates this choice as suitable for a wide spectrum language to be used for designs as well as initial specifications, and supporting imperative and concurrent...

  12. The Logic of the RAISE Specification Language

    DEFF Research Database (Denmark)

    George, Chris; Haxthausen, Anne Elisabeth

    2008-01-01

    This chapter describes the logic of the RAISE Specification Language, RSL. It explains the particular logic chosen for RAISE, and motivates this choice as suitable for a wide spectrum language to be used for designs as well as initial specifications, and supporting imperative and concurrent...

  13. The College President's Role in Fund Raising.

    Science.gov (United States)

    Miller, Michael T.

    The role of the college president as one of the chief actors in academic fund raising is examined against the background of today's period of financial caution and increased competition for philanthropic support. The paper first provides an overview of the state of the art of fund raising and some ways in which college and universities have…

  14. GROWTH AND BEHAVIOR OF LARVAL ZEBRAFISH Danio ...

    Science.gov (United States)

    Because Zebrafish (Danio rerio) have become a popular and important model for scientific research, the capability to rear larval zebrafish to adulthood is of great importance. Recently research examining the effects of diet (live versus processed) have been published. In the current study we examined whether the larvae can be reared on a processed diet alone, live food alone, or the combination while maintaining normal locomotor behavior, and acceptable survival, length and weight at 14 dpf in a static system. A 14 day feeding trial was conducted in glass crystallizing dishes containing 500 ml of 4 ppt Instant Ocean. On day 0 pdf 450 embryos were selected as potential study subjects and placed in a 26○C incubator on a 14:10 (light:dark) light cycle. At 4 dpf 120 normally developing embryos were selected per treatment and divided into 3 bowls of 40 embryos (for an n=3 per treatment; 9 bowls total). Treatment groups were: G (Gemma Micro 75 only), R (L-type marine rotifers (Brachionus plicatilis) only) or B (Gemma and rotifers). Growth (length), survival, water quality and rotifer density were monitored on days 5-14. On day 14, weight of larva in each bowl was measured and 8 larva per bowl were selected for use in locomotor testing. This behavior paradigm tests individual larval zebrafish under both light and dark conditions in a 24-well plate.After 14 dpf, survival among the groups was not different (92-98%). By days 7 -14 R and B larvae were ~2X longer

  15. Mosquito larval source management for controlling malaria

    Science.gov (United States)

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2015-01-01

    Background Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). Objectives To evaluate the effectiveness of mosquito LSM for preventing malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. Selection criteria We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. Data collection and analysis At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software

  16. Evidence for Isostatic Emergence and Holocene Environmental Change Recorded in Chironomid Assemblages and Sediment Composition of Coastal Lake T1 in SW Greenland

    Science.gov (United States)

    Berman, K.; Axford, Y.; Lasher, G. E.

    2017-12-01

    Multi-proxy analysis of a coastal lake in southwest Greenland near Nuuk provides evidence for regional environmental changes, including the timing of isostatic rebound and the temperature history of the area. T1 (informal name) is a small lake 50 km south of Nuuk, at 17.5 m elevation and currently isolated from glacial meltwater drainage. The lake's sediment record begins approximately 9500 cal years BP, when the site was submerged beneath sea level due to glacial isostatic depression following the Last Glacial Maximum. The record captures the transition of the environment from a submerged, glacially-influenced marine site to a non-glacially fed (and initially meromictic) freshwater lake 8600 cal years BP. Magnetic susceptibility, a proxy for sediment minerogenic content, decreased rapidly from 9500 to 8600 years BP, before abruptly stabilizing and remaining relatively low and steady for the rest of the record. The transition to a lacustrine environment was characterized by a rapid and relatively simultaneous increase in primary productivity (inferred from biogenic silica concentrations) and shift towards terrestrial versus marine sources of organic matter (inferred from carbon:nitrogen ratios and nitrogen isotopes) between 8700 and 8400 years BP. Together, these proxies and the presence of marine shells below the transition provide robust evidence for the transition from a marine environment to a freshwater lake in response to regional postglacial isostatic rebound. Within the Holocene, measures of bulk sediment composition (e.g., biogenic silica, loss-on-ignition and magnetic susceptibility) are relatively stable. Chironomid (Insecta: Diptera: Chironomidae) assemblages, which in some environments are quantitative proxies for summer temperature changes, show species-level shifts within the Holocene that will be interpreted in this presentation alongside indicators of landscape change including carbon:nitrogen ratios, bulk sediment spectral reflectance and bulk

  17. Paleoecología: el uso de los quironómidos fósiles (Diptera: Chironomidae en reconstrucciones paleoambientales durante el Cuaternario en la Patagonia Paleoecology: the use of fossil chironomids (Diptera: Chironomidae for paleoenvironmental reconstructions in Patagonia

    Directory of Open Access Journals (Sweden)

    Julieta Massaferro

    2009-06-01

    Full Text Available Entre los indicadores biológicos lacustres más utilizados en las reconstrucciones ambientales, se encuentran el polen, los ostrácodos y las diatomeas, y entre los insectos, los coleópteros y los quironómidos. Este grupo ha cobrado gran importancia en los últimos tiempos, debido a los resultados prometedores que se han obtenido en reconstrucciones climáticas realizadas en América del Norte y Europa. En América del Sur, el uso de los quironómidos fósiles en estudios cuaternarios es relativamente limitado, principalmente por su escaso conocimiento taxonómico regional. La mayor parte de estos estudios fueron realizados en lagos glaciares patagónicos de Argentina y Chile. Las larvas de quironómidos constituyen una valiosa herramienta paleolimnológica, por ser un grupo de organismos altamente sensible a cambios ambientales, tanto naturales como artificiales. Además, es un grupo de insectos ampliamente distribuido y con una abundancia y diversidad relativamente altas. Sus cápsulas cefálicas se preservan en los sedimentos lacustres y poseen caracteres importantes que permiten identificar géneros y muchas veces especies. El estudio de los ensambles de quironómidos en sedimentos lacustres puede ser utilizado con distintos objetivos, por ejemplo, para estudios de eutrofización, ya que responden rápidamente a cambios en la concentración de nutrientes, materia orgánica y otros elementos, como metales pesados. No obstante, uno de los potenciales más importantes de este grupo de insectos es su sensibilidad a los cambios de temperatura, por este motivo, la aplicación más importante de su estudio en sedimentos se centra en las reconstrucciones climáticas. Esta contribución es una síntesis de los resultados de los trabajos publicados en la Patagonia argentina y chilena, sobre la base del uso de los quironómidos fósiles en reconstrucciones paleoambientales.Pollen, ostracods, diatoms and insects such as beetles and chironomids are

  18. Parenting Skills: Tips for Raising Teens

    Science.gov (United States)

    ... adult is no small task. Understand the parenting skills you need to help guide your teen. By ... teen and encourage responsible behavior. Use these parenting skills to deal with the challenges of raising a ...

  19. Measurements and Counts for Larval and Juvenile Beryx Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Larval alfonsin (Beryx species) were collected in the vicinity of the Southeast Hancock Seamount. A three-net Tucker trawl (I m2 effective mouth opening and 0.333 mm...

  20. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    OpenAIRE

    Gendrin, MEM; Christophides; Linenberg, Inbar

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii . We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clar...

  1. Contributions for larval development optimization of Homarus gammarus

    Directory of Open Access Journals (Sweden)

    Pedro Tiago Fonseca Sá

    2014-06-01

    The seawater rising temperature resulted in a decrease of intermoult period in all larval development stages and at all tested temperatures, ranging from 4.77 (Z1 to 16.5 days (Z3 at 16°C, whereas at 23°C, ranged from 3:02 (Z1 and 9.75 days (Z3. The results obtained are an extremely useful guide for future optimization of protocols on larval development of H. gammarus.

  2. Ant-Related Oviposition and Larval Performance in a Myrmecophilous Lycaenid

    Directory of Open Access Journals (Sweden)

    Matthew D. Trager

    2013-01-01

    Full Text Available We experimentally assessed ant-related oviposition and larval performance in the Miami blue butterfly (Cyclargus thomasi bethunebakeri. Ant tending had sex-dependent effects on most measures of larval growth: female larvae generally benefitted from increased tending frequency whereas male larvae were usually unaffected. The larger size of female larvae tended by ants resulted in a substantial predicted increase in lifetime egg production. Oviposition by adult females that were tended by C. floridanus ants as larvae was similar between host plants with or without ants. However, they laid relatively more eggs on plants with ants than did females raised without ants, which laid less than a third of their eggs on plants with ants present. In summary, we found conditional benefits for larvae tended by ants that were not accompanied by oviposition preference for plants with ants present, which is a reasonable result for a system in which ant presence at the time of oviposition is not a reliable indicator of future ant presence. More broadly, our results emphasize the importance of considering the consequences of variation in interspecific interactions, life history traits, and multiple measures of performance when evaluating the costs and benefits of mutualistic relationships.

  3. Helminths parasitizing larval fish from Pantanal, Brazil.

    Science.gov (United States)

    Lacerda, A C F; Santin, M; Takemoto, R M; Pavanelli, G C; Bialetzki, A; Tavernari, F C

    2009-03-01

    Fish larvae of 'corvinas' (Pachyurus bonariensis and Plagioscion ternetzi) from Sinhá Mariana Lagoon, Mato Grosso State, were collected from March 2000 to March 2004, in order to determine the parasitic fauna of fishes. Larvae from the two species were parasitized by the same endoparasites: Contracaecum sp. Type 2 (larvae) (Nematoda: Anisakidae) in the mesentery and Neoechinorhynchus (Neoechinorhynchus) paraguayensis (Acanthocephala: Neoechinorhynchidae) in the stomach and the terminal portion of the intestine. Statistical analysis showed that there was a significant positive correlation between the standard length of hosts and the abundance of acanthocephalans and nematodes, and that the prevalence of nematodes presented a significant positive correlation with the standard length of the two species of hosts, indicating the presence of a cumulative process of infection. The present study constitutes the first record of nematodes and acanthocephalans parasitizing larval fish, as well as the first record of endoparasites in fish larvae in Brazil. In addition, it lists a new locality and two species of hosts for Contracaecum sp. Type 2 (larva) and N. (N.) paraguayensis.

  4. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  5. Assessment of sampling mortality of larval fishes

    International Nuclear Information System (INIS)

    Cada, G.F.; Hergenrader, G.L.

    1978-01-01

    A study was initiated to assess the mortality of larval fishes that were entrained in the condenser cooling systems of two nuclear power plants on the Missouri River in Nebraska. High mortalities were observed not only in the discharge collections but also in control samples taken upriver from the plants where no entrainment effects were possible. As a result, entrainment mortality generally could not be demonstrated. A technique was developed which indicated that (1) a significant portion of the observed mortality above the power plants was the result of net-induced sampling mortality, and (2) a direct relationship existed between observed mortality and water velocity in the nets when sampling at the control sites, which was described by linear regression equations. When these equations were subsequently used to remove the effects of wide differences in sampling velocities between control and discharge collections, significant entrainment mortality was noted in all cases. The equations were also used to derive estimates of the natural mortality of ichthyoplankton in this portion of the Missouri River

  6. Sandeel ( Ammodytes marinus ) larval transport patterns in the North Sea from an individual-based hydrodynamic egg and larval model

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Jensen, Henrik; Mosegaard, Henrik

    2008-01-01

    We have calculated a time series of larval transport indices for the central and southern North Sea covering 1970-2004, using a combined three-dimensional hydrodynamic and individual-based modelling framework for studying sandeel (Ammodytes marinus) eggs, larval transport, and growth. The egg phase...... is modelled by a stochastic, nonlinear degree-day model describing the extended hatch period. The larval growth model is parameterized by individually back-tracking the local physical environment of larval survivors from their catch location and catch time. Using a detailed map of sandeel habitats...... analyzed, and we introduce novel a scheme to quantify direct and indirect connectivity on equal footings in terms of an interbank transit time scale....

  7. High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica.

    Science.gov (United States)

    Bylenga, Christine H; Cummings, Vonda J; Ryan, Ken G

    2017-01-01

    Environmental stressors impact marine larval growth rates, quality and sizes. Larvae of the Antarctic bivalve, Laternula elliptica, were raised to the D-larvae stage under temperature and pH conditions representing ambient and end of century projections (-1.6°C to +0.4°C and pH 7.98 to 7.65). Previous observations using light microscopy suggested pH had no influence on larval abnormalities in this species. Detailed analysis of the shell using SEM showed that reduced pH is in fact a major stressor during development for this species, producing D-larvae with abnormal shapes, deformed shell edges and irregular hinges, cracked shell surfaces and even uncalcified larvae. Additionally, reduced pH increased pitting and cracking on shell surfaces. Thus, apparently normal larvae may be compromised at the ultrastructural level and these larvae would be in poor condition at settlement, reducing juvenile recruitment and overall survival. Elevated temperatures increased prodissoconch II sizes. However, the overall impacts on larval shell quality and integrity with concurrent ocean acidification would likely overshadow any beneficial results from warmer temperatures, limiting populations of this prevalent Antarctic species.

  8. High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica.

    Directory of Open Access Journals (Sweden)

    Christine H Bylenga

    Full Text Available Environmental stressors impact marine larval growth rates, quality and sizes. Larvae of the Antarctic bivalve, Laternula elliptica, were raised to the D-larvae stage under temperature and pH conditions representing ambient and end of century projections (-1.6°C to +0.4°C and pH 7.98 to 7.65. Previous observations using light microscopy suggested pH had no influence on larval abnormalities in this species. Detailed analysis of the shell using SEM showed that reduced pH is in fact a major stressor during development for this species, producing D-larvae with abnormal shapes, deformed shell edges and irregular hinges, cracked shell surfaces and even uncalcified larvae. Additionally, reduced pH increased pitting and cracking on shell surfaces. Thus, apparently normal larvae may be compromised at the ultrastructural level and these larvae would be in poor condition at settlement, reducing juvenile recruitment and overall survival. Elevated temperatures increased prodissoconch II sizes. However, the overall impacts on larval shell quality and integrity with concurrent ocean acidification would likely overshadow any beneficial results from warmer temperatures, limiting populations of this prevalent Antarctic species.

  9. Survival of Salmonella enterica in Freshwater and Sediments and Transmission by the Aquatic Midge Chironomus tentans (Chironomidae: Diptera)

    Science.gov (United States)

    Moore, Barry C.; Martinez, Edward; Gay, John M.; Rice, Daniel H.

    2003-01-01

    Survival of a nalidixic acid-resistant strain of Salmonella enterica serovar Typhimurium mr-DT-104 in water and sediments was tested using artificially contaminated aquaria. Water samples remained culture positive for salmonella for up to 54 days. Sediment samples were culture positive up to 119 days. In addition, potential mechanisms for spreading salmonella in the environments by chironomid larvae and adults were tested. We evaluated the acquisition of mr-DT-104 by chironomids from contaminated aquatic sediments and subsequent spread to uncontaminated sediments. Larval chironomids raised in contaminated sediments became culture positive, and the bacteria were carried over to adults after emergence. Contamination of clean sediments by chironomid larvae was not demonstrated. These findings clearly suggest that mr-DT-104 serovar organisms can survive in aquatic sediments for at least several months. Uptake of salmonellae by chironomid larvae and adults suggests that they are possible vectors of mr-DT-104 in both aquatic and terrestrial environments, although the role of larval defecation in movement of bacteria to new sediments was not demonstrated. PMID:12902242

  10. Raising venture capital in the biopharma industry.

    Science.gov (United States)

    Leytes, Lev J

    2002-11-15

    Raising venture capital (VC) is both an art and a science. Future entrepreneurs should carefully consider the various issues of VC financing that have a strong impact on the success of their business. In addition to attracting the best venture capital firms, these issues include such subtle but important points as the timing of financing (especially of the first round), external support sources, desirable qualities of a VC firm, amount to be raised, establishing a productive interface between the founders and the venture capitalists, and most importantly the effects of well-executed VC funding on hiring senior executives and scientific leaders.

  11. Leaf litter as a possible food source for chironomids (Diptera in Brazilian and Portuguese headwater streams Detritos foliares como possível fonte de alimento para Chironomidae (Diptera em riachos de cabeceira brasileiros e portugueses

    Directory of Open Access Journals (Sweden)

    Marcos Callisto

    2007-06-01

    Full Text Available Our objective was to evaluate the potential use of leaf detritus by chironomid larvae. Field and laboratory experiments were performed using leaves and chironomid species collected in Portugal and Brazil. Laboratory experiments under controlled conditions were done using microbial conditioned senescent leaves of Alnus glutinosa (L. Gaertn, Neriumoleander L., Protium heptaphilum (Aubl. March, Protium brasiliense (Spreng Engl., Myrcia guyanensis(Aubl. DC and Miconia chartacea Triana. Laboratory experiments were performed using specimens collected from leaf litter in local streams. Whenever possible, after the experiments, chironomids were allowed to emerge as adults and identified. In Portugal the following taxa were identified: Micropsectra apposita (Walker, 1856, Polypedilum albicorne (Meigen, 1838,Eukiefferiella claripennis Lundbeck (1898, Rheocricotopus (Psilocricotopus atripes Rempel (1937 and Ablabesmyia Johannsen (1905 (Diptera, Chironomidae. Consumption rates ranged from 0.15 ± 0.10 mg (AFDM of leaf animal-1 day-1 (Micropsectra apposita feeding on Alnus glutinosa up to 0.85 ± 0.33 mg (AFDM of leaf animal-1 day-1 (Polypedilum albicorne feeding on Miconia chartacea. In Brazil, the following taxa were identified from leaves: Phaenopsectra sp., Chironomus spp. and Polypedilum sp. and maximum consumption rates reached 0.47 ± 0.28 (AFDM of leaf mg.animal-1.day-1 (Chironomus Meigen (1803 feeding on Protium heptaphilum. Feeding experiments with laboratory cultured specimens, revealed that some chironomids were unable to feed on decomposing leaves (e.g., C. xanthus Rempel (1939 on P.brasiliensis and M.guyanensis. Our results suggest that some stream chironomids (not typical shredders can use leaf litter of riparian vegetation as a complementary food source.O objetivo foi avaliar o potencial uso de detritos foliares por larvas de Chironomidae. Foram realizados experimentos em campo e em laboratório utilizando folhas e larvas de Chironomidae

  12. People on the Farm: Raising Beef Cattle.

    Science.gov (United States)

    Crain, Robert L.

    This booklet provides information on raising beef cattle through profiles of two families, the Ritschards of Colorado and the Schuttes of Missouri. Through descriptions of daily life for these families, the booklet discusses the way of life on modern beef cattle farms and the problems and decisions faced by farmers. The booklet explains how…

  13. RAISING BRAND AWARENEES THROUGH INTERNET MARKETING TOOLS

    Directory of Open Access Journals (Sweden)

    Margarita Išoraitė

    2016-05-01

    Full Text Available The article analyzes the opinions of different authors on brand awareness raising. It also describes and analyzes the concept of internet marketing, the implementation. The analysis of the most urgent and the most effective online marketing tools brand awareness. Article analysis website; internet advertising; social networks; search engine optimization.

  14. School Perceptions of Children Raised by Grandparents

    Science.gov (United States)

    Edwards, Oliver W.

    2018-01-01

    Increasing numbers of children raised by grandparents are students in schools. Their substitute family structure and precursors to the emergence of this family structure have implications for the children's school performance. Research suggests teachers view these children as at risk for difficult school functioning. The aforementioned judgment is…

  15. Raising Butterflies from Your Own Garden.

    Science.gov (United States)

    Howley-Pfeifer, Patricia

    2002-01-01

    Describes how raising monarch, black swallowtail, and mourning cloak butterflies in a kindergarten class garden can provide opportunities for observation experiences. Includes detailed steps for instruction and describes stages of growth. Excerpts children's journal dictations to illustrate ways to support the discovery process. Describes related…

  16. Experimental immunization of ponies with Strongylus vulgaris radiation-attenuated larvae or crude soluble somatic extracts from larval or adult stages.

    Science.gov (United States)

    Monahan, C M; Taylor, H W; Chapman, M R; Klei, T R

    1994-12-01

    Protection from Strongylus vulgaris infection through immunization with radiation-attenuated third-stage larvae (L3) or crude soluble homogenates from larval or adult stages was examined. Yearling ponies raised parasite-free were divided into 3 immunization groups: radiation-attenuated L3; soluble adult somatic extracts; larval somatic extracts with excretory/secretory products (E/S) from in vitro culture; and 1 medium control group. Ponies were immunized twice; attenuated larvae were administered orally and somatic extracts or controls injected intramuscularly with adjuvant. Approximately 6 wk following the second immunization, all ponies were challenged. Necrospy examinations were performed 6 wk following challenge. Irradiated larvae recipients had the fewest postchallenge clinical signs and lesions and were 91% protected from infection determined by larval recoveries from arterial dissections. Soluble antigen recipients and controls had similar larval recoveries and thus equal susceptibility to challenge. Soluble antigen recipients had more severe clinical signs and lesions than controls, suggesting that parenteral immunization exacerbated postchallenge inflammatory responses. Protection by immunization with irradiated larvae was associated with an anamnestic eosinophilia and postimmunization antibody recognition of S. vulgaris L3 surface antigens. Histologic staining of eosinophils within tissues of this group suggested that this immunization induced a cytophilic antibody response that facilitated degranulation.

  17. Larval dispersal in three coral reef decapod species: Influence of larval duration on the metapopulation structure

    Science.gov (United States)

    Zavala-Hidalgo, Jorge; Allende-Arandía, Eugenia; Hermoso-Salazar, Margarita

    2018-01-01

    Most coral-associated decapod species have non-migratory adult populations and depend on their planktonic larvae for dispersal. This study examined the metapopulation structure of three decapod species with different pelagic larval duration (PLD) from twelve coral reef complexes of the Gulf of Mexico. The dispersion of larvae was analyzed through the use of a realistic numerical simulation of the Gulf of Mexico with the Hybrid Coordinate Ocean Model. To study the transport and dispersion of particles in near-surface waters, a particle-tracking subroutine was run using as input the currents from the model. The simulation consisted of the launch of 100 passive particles (virtual larvae) every 24 hours from each reef throughout five years, and tracked for as long as 210 days. Results indicated that species with a short PLD, Mithraculus sculptus (PLD 8‒13 days), had a weak connection among the reefs, but higher self-recruitment, especially on the narrow western shelf. The species with a longer PLD, Dromia erythropus (28‒30 days), had a stronger connection among neighboring reefs (< 300 km). Finally, the species with an even longer PLD, Stenopus hispidus (123‒210 days), had a wider potential distribution than the other species. Circulation on synoptic, seasonal and interannual scales had differential effects on the larval dispersal of each species. The metapopulation structure of M. sculptus and D. erythropus seemed to combine features of the non-equilibrium and the patchy models, whereas that of S. hispidus presumably fit to a patchy model. These findings support previous observations that indicate that species with longer PLD tend to occupy larger areas than species with short PLD, although recruitment of juveniles to the adult populations will also depend on other factors, such as the availability of suitable habitats and the ability to colonize them. PMID:29558478

  18. Effects of two stressors on amphibian larval development.

    Science.gov (United States)

    Stark, Karolina; Scott, David E; Tsyusko, Olga; Coughlin, Daniel P; Hinton, Thomas G

    2012-05-01

    In parallel with a renewed interest in nuclear power and its possible environmental impacts, a new environmental radiation protection system calls for environmental indicators of radiological stress. However, because environmental stressors seldom occur alone, this study investigated the combined effects of an ecological stressor (larval density) and an anthropogenic stressor (ionizing radiation) on amphibians. Scaphiopus holbrookii tadpoles reared at different larval densities were exposed to four low irradiation dose rates (0.13, 2.4, 21, and 222 mGy d(-1)) from (137)Cs during the sensitive period prior to and throughout metamorphosis. Body size at metamorphosis and development rate served as fitness correlates related to population dynamics. Results showed that increased larval density decreased body size but did not affect development rate. Low dose rate radiation had no impact on either endpoint. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Effects of beach morphology and waves on onshore larval transport

    Science.gov (United States)

    Fujimura, A.; Reniers, A.; Paris, C. B.; Shanks, A.; MacMahan, J.; Morgan, S.

    2015-12-01

    Larvae of intertidal species grow offshore, and migrate back to the shore when they are ready to settle on their adult substrates. In order to reach the habitat, they must cross the surf zone, which is characterized as a semi-permeable barrier. This is accomplished through physical forcing (i.e., waves and current) as well as their own behavior. Two possible scenarios of onshore larval transport are proposed: Negatively buoyant larvae stay in the bottom boundary layer because of turbulence-dependent sinking behavior, and are carried toward the shore by streaming of the bottom boundary layer; positively buoyant larvae move to the shore during onshore wind events, and sink to the bottom once they encounter high turbulence (i.e., surf zone edge), where they are carried by the bottom current toward the shore (Fujimura et al. 2014). Our biophysical Lagrangian particle tracking model helps to explain how beach morphology and wave conditions affect larval distribution patterns and abundance. Model results and field observations show that larval abundance in the surf zone is higher at mildly sloped, rip-channeled beaches than at steep pocket beaches. Beach attributes are broken up to examine which and how beach configuration factors affect larval abundance. Modeling with alongshore uniform beaches with variable slopes reveal that larval populations in the surf zone are negatively correlated with beach steepness. Alongshore variability enhances onshore larval transport because of increased cross-shore water exchange by rip currents. Wave groups produce transient rip currents and enhance cross-shore exchange. Effects of other wave components, such as wave height and breaking wave rollers are also considered.

  20. Head raising analysis and case revaluation

    Directory of Open Access Journals (Sweden)

    Ager Gondra

    2015-12-01

    Full Text Available This paper shows that Basque relative clause construction follows the Head Raising Analysis: the CP of the relative clause is a complement to the external D and the Head of the relative clause, base-generated inside the TP, moves to the specifier position of the CP. This analysis predicts that the raised DPwill show a TP-internal Case. However, this is not the case, and the DP manifests the Case associated with the main clause. In order to address these Case inconsistencies, Precariousness Condition is proposed. This condition states that a DCase valued u-feature is precarious until it is sent to Spell-Out and therefore, the value is visible for further targeting by a c-commanding Probe.  Evidence for this multiple Agree operation comes from a DP long distance extraction.

  1. Polycystic echinococcosis in Colombia: the larval cestodes in infected rodents.

    Science.gov (United States)

    Morales, G A; Guzman, V H; Wells, E A; Angel, D

    1979-07-01

    Described are the characteristics of the polycystic larval cestodes found in an endemic area of echinococcosis in the Easter Plains of Colombia and the tissue reaction evoked in infected rodents. Of 848 free-ranging animals examined, polycystic hydatids were found in 44/93 Cuniculus paca and 1/369 Proechimys sp. None of 20 Dasyprocta fuliginosa examined was infected, but hunters provided a heart with hydatid cysts and information about two additional animals with infected livers. Recognition of an endemic area of polycystic echinococcosis provides a means to investigate the life cycle of the parasites and to study the histogenesis of the larval cestodes in susceptible laboratory animals.

  2. The neural basis of visual behaviors in the larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2009-12-01

    We review visually guided behaviors in larval zebrafish and summarise what is known about the neural processing that results in these behaviors, paying particular attention to the progress made in the last 2 years. Using the examples of the optokinetic reflex, the optomotor response, prey tracking and the visual startle response, we illustrate how the larval zebrafish presents us with a very promising model vertebrate system that allows neurocientists to integrate functional and behavioral studies and from which we can expect illuminating insights in the near future. Copyright 2009 Elsevier Ltd. All rights reserved.

  3. Organogénesis durante el periodo larval en peces

    OpenAIRE

    Zavala-Leal, I; Dumas, Silvie; Peña Martínez, Renato

    2011-01-01

    La presencia de un periodo larval caracteriza a los peces con ontogenia indirecta. Este periodo de desarrollo implica una serie de transformaciones encaminadas a la adquisición de las características biológicas y ecológicas propias de la especie; y en muchos casos culmina con cambios de distribución y hábitos alimenticios. El periodo larval incluye cuatro estadios de desarrollo: larva vitelina, larva pre-flexión, larva flexión y larva post-flexión. Cada estadio de desarrollo presenta caracter...

  4. Do Firms Go Public to Raise Capital?

    OpenAIRE

    Woojin Kim; Michael Weisbach

    2005-01-01

    This paper considers the question of whether raising capital is an important reason why firms go public. Using a sample of 16,958 initial public offerings from 38 countries between 1990 and 2003, we consider differences between firms that sell new, primary shares to the public, and existing secondary shares that previously belonged to insiders. Our results suggest that the sale of primary shares is correlated with a number of factors associated with the firm's demand for capital. In particula...

  5. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    NARCIS (Netherlands)

    Bukhari, S.T.; Middelman, A.; Koenraadt, C.J.M.; Takken, W.; Knols, B.G.J.

    2010-01-01

    Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (species

  6. Diel and lunar variations in larval supply to Malindi Marine Park ...

    African Journals Online (AJOL)

    Understanding larval ecology and the mechanisms used in dispersal and habitat selection helps to better understand the population dynamics of coral reef communities. However, few studies have examined patterns of larval supply to reefs sites especially in the WIO region. Temporal patterns of fish larval occurrence in ...

  7. File list: InP.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.10.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.10.AllAg.Larval_brain.bed ...

  8. File list: His.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.50.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.50.AllAg.Larval_brain.bed ...

  9. File list: ALL.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.Larval_brain.bed ...

  10. File list: InP.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.20.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.20.AllAg.Larval_brain.bed ...

  11. Vegetative substrates used by larval northern pike in Rainy and Kabetogama Lakes, Minnesota

    Science.gov (United States)

    Anne L. Timm; Rodney B. Pierce

    2015-01-01

    Our objective was to identify characteristics of aquatic vegetative communities used as larval northern pike nursery habitat in Rainy and Kabetogama lakes, glacial shield reservoirs in northern Minnesota. Quatrefoil light traps fished at night were used to sample larval northern pike in 11 potential nursery areas. Larval northern pike were most commonly sampled among...

  12. File list: InP.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.50.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.50.AllAg.Larval_brain.bed ...

  13. File list: ALL.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.Larval_brain.bed ...

  14. File list: ALL.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426946,SRX1426943 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.Larval_brain.bed ...

  15. File list: ALL.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.10.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426943,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.10.AllAg.Larval_brain.bed ...

  16. File list: InP.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.05.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.05.AllAg.Larval_brain.bed ...

  17. File list: His.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426945,SRX1426943... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.10.AllAg.Larval_brain.bed ...

  18. File list: His.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.20.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.20.AllAg.Larval_brain.bed ...

  19. Live weight and body measurements of male and female native ducks raised in different raising systems

    Directory of Open Access Journals (Sweden)

    Kadir Önk

    2018-05-01

    Full Text Available ABSTRACT The purpose of this study was to determine live weight and body measurements of male and female native ducks raised in different raising systems. One hundred and twenty native ducks (60 males, 60 females were used in the study. The ducks were raised in deep litter floor and cage systems. Live weight and body values were measured every two weeks, until they were 56 days old. Three-parameter logistic regression and Gompertz model were used to determine growth model of male and female ducks. Interactions of time-raising system and time-sex were statistically significant in terms of live weight. At the end of eight weeks, live weights of ducks raised in deep litter floor were higher than ducks raised in cage system. In addition, live weights of male ducks were higher than female ducks. Consequently, deep litter floor is more appropriate for live weight in native ducks. Accuracy rate of Three-parameter Logistic and Gompertz models for estimation of growth in ducks was between 0.91-0.95 and similar results were obtained from both models. The Gompertz model is appropriate for the data structure of this study because it contains fewer iterations than the Three-Parameter Logistic model.

  20. Integrated mosquito larval source management reduces larval numbers in two highland villages in western Kenya

    Directory of Open Access Journals (Sweden)

    Imbahale Susan S

    2012-05-01

    Full Text Available Abstract Background In western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures. Methods Larval source management (LSM of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil, habitat manipulation (by provision of shading from arrow root plant, application of Bacillus thuringiensis var israelensis (Bti and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats. Results The findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89 % and 91 % chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively. Conclusion Most of these interventions were applied in habitats

  1. Larval diet affects mosquito development and permissiveness to Plasmodium infection.

    Science.gov (United States)

    Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

    2016-12-02

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

  2. Larval biology of the crab Rhithropanopeus harrisii (Gould): a synthesis.

    Science.gov (United States)

    Forward, Richard B

    2009-06-01

    This synthesis reviews the physiological ecology and behavior of larvae of the benthic crab Rhithropanopeus harrisii, which occurs in low-salinity areas of estuaries. Larvae are released rhythmically around the time of high tide in tidal estuaries and in the 2-h interval after sunset in nontidal estuaries. As in most subtidal crustaceans, the timing of larval release is controlled by the developing embryos, which release peptide pheromones that stimulate larval release behavior by the female to synchronize the time of egg hatching. Larvae pass through four zoeal stages and a postlarval or megalopal stage that are planktonic before metamorphosis. They are retained near the adult population by means of an endogenous tidal rhythm in vertical migration. Larvae have several safeguards against predation: they undergo nocturnal diel vertical migration (DVM) and have a shadow response to avoid encountering predators, and they bear long spines as a deterrent. Photoresponses during DVM and the shadow response are enhanced by exposure to chemical cues from the mucus of predator fishes and ctenophores. The primary visual pigment has a spectral sensitivity maximum at about 500 nm, which is typical for zooplankton and matches the ambient spectrum at twilight. Larvae can detect vertical gradients in temperature, salinity, and hydrostatic pressure, which are used for depth regulation and avoidance of adverse environmental conditions. Characteristics that are related to the larval habitat and are common to other crab larval species are considered.

  3. Basolateral Cl- channels in the larval bullfrog skin epithelium

    DEFF Research Database (Denmark)

    Hillyard, Stanley D.; Rios, K.; Larsen, Erik Hviid

    2002-01-01

    The addition of 150 U/ml nystatin to the mucosal surface of isolated skin from larval bullfrogs increases apical membrane permeability and allows a voltage clamp to be applied to the basolateral membrane. With identical Ringer's solutions bathing either side of the tissue the short-circuit curren...

  4. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th ...

  5. A larval hunger signal in the bumblebee Bombus terrestris

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Duchateau, Marie-Jose

    2006-01-01

    Larvae of Bombus terrestris, a pollen-storing bumblebee, are dependent on progressive provisioning by workers. We test the hypothesis that larval cuticular chemicals can act as a hunger signal. We first show with a new classical conditioning experiment, using a Y-shaped tube, that workers can...

  6. Estimation of larval density of Liriomyza sativae Blanchard (Diptera ...

    African Journals Online (AJOL)

    This study was conducted to develop sequential sampling plans to estimate larval density of Liriomyza sativae Blanchard (Diptera: Agromyzidae) at three precision levels in cucumber greenhouse. The within- greenhouse spatial patterns of larvae were aggregated. The slopes and intercepts of both Iwao's patchiness ...

  7. Hypothalamic Projections to the Optic Tectum in Larval Zebrafish

    Science.gov (United States)

    Heap, Lucy A.; Vanwalleghem, Gilles C.; Thompson, Andrew W.; Favre-Bulle, Itia; Rubinsztein-Dunlop, Halina; Scott, Ethan K.

    2018-01-01

    The optic tectum of larval zebrafish is an important model for understanding visual processing in vertebrates. The tectum has been traditionally viewed as dominantly visual, with a majority of studies focusing on the processes by which tectal circuits receive and process retinally-derived visual information. Recently, a handful of studies have shown a much more complex role for the optic tectum in larval zebrafish, and anatomical and functional data from these studies suggest that this role extends beyond the visual system, and beyond the processing of exclusively retinal inputs. Consistent with this evolving view of the tectum, we have used a Gal4 enhancer trap line to identify direct projections from rostral hypothalamus (RH) to the tectal neuropil of larval zebrafish. These projections ramify within the deepest laminae of the tectal neuropil, the stratum album centrale (SAC)/stratum griseum periventriculare (SPV), and also innervate strata distinct from those innervated by retinal projections. Using optogenetic stimulation of the hypothalamic projection neurons paired with calcium imaging in the tectum, we find rebound firing in tectal neurons consistent with hypothalamic inhibitory input. Our results suggest that tectal processing in larval zebrafish is modulated by hypothalamic inhibitory inputs to the deep tectal neuropil. PMID:29403362

  8. Study on Silkworm Bed Cleaning Frequency during Larval Growth ...

    African Journals Online (AJOL)

    Study on Silkworm Bed Cleaning Frequency during Larval Growth Period. Abiy Tilahun, Kedir Shifa, Ahmed Ibrahim, Metasebia Terefe. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/star.v4i2.5 · AJOL African ...

  9. Body shape, burst speed and escape behavior of larval anurans

    Science.gov (United States)

    Gage H. Dayton; Daniel Saenz; Kristen A. Baum; R. Brian Langerhans; Thomas J. DeWitt

    2005-01-01

    Variation in behavior, morphology and life history traits of larval anurans across predator gradients, and consequences of that variation, have been abundantly studied. Yet the functional link between morphology and burst-swimming speed is largely unknown. We conducted experiments with two divergent species of anurans, Scaphiopus holbrookii and

  10. Population dynamics and management implications of larval dispersal

    African Journals Online (AJOL)

    caused by the identified mechanism provides: (1) the basis for spatially explicit management, and (2) an explanation for the observed spatial variability in the degree of overfishing. Research on larval dispersal is also providing the information necessary to design spatially explicit management strategies involving either ...

  11. Mosquito larval habitats and public health implications in Abeokuta ...

    African Journals Online (AJOL)

    The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette.

  12. Stretch-activated cation channel from larval bullfrog skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Willumsen, Niels J; Marrero, Mario B

    2010-01-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (-1 kPa to -4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed ...

  13. The larval development and population dynamics of Derocheilocaris ...

    African Journals Online (AJOL)

    Seven larval stages of Derocheilocaris algoensis have been described and appear to be identical with those of D. typica from North America. This stresses the remarkable conservativeness of this subclass of Crustacea. The population biology of D. algoensis has been studied over 16 months and reproduction has been ...

  14. Fruit Fly Liquid Larval Diet Technology Transfer and Update

    Science.gov (United States)

    Since October 2006, USDA-ARS has been implementing a fruit fly liquid larval diet technology transfer, which has proceeded according to the following steps: (1) Recruitment of interested groups through request; (2) Establishment of the Material Transfer Agreement (MTA) with ARS; (3) Fruit fly liquid...

  15. Hypothalamic Projections to the Optic Tectum in Larval Zebrafish

    Directory of Open Access Journals (Sweden)

    Lucy A. Heap

    2018-01-01

    Full Text Available The optic tectum of larval zebrafish is an important model for understanding visual processing in vertebrates. The tectum has been traditionally viewed as dominantly visual, with a majority of studies focusing on the processes by which tectal circuits receive and process retinally-derived visual information. Recently, a handful of studies have shown a much more complex role for the optic tectum in larval zebrafish, and anatomical and functional data from these studies suggest that this role extends beyond the visual system, and beyond the processing of exclusively retinal inputs. Consistent with this evolving view of the tectum, we have used a Gal4 enhancer trap line to identify direct projections from rostral hypothalamus (RH to the tectal neuropil of larval zebrafish. These projections ramify within the deepest laminae of the tectal neuropil, the stratum album centrale (SAC/stratum griseum periventriculare (SPV, and also innervate strata distinct from those innervated by retinal projections. Using optogenetic stimulation of the hypothalamic projection neurons paired with calcium imaging in the tectum, we find rebound firing in tectal neurons consistent with hypothalamic inhibitory input. Our results suggest that tectal processing in larval zebrafish is modulated by hypothalamic inhibitory inputs to the deep tectal neuropil.

  16. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands .... be used in the silk-manufacture industry. This paper analyses .... (figure 3C); and are highly birefringent (figure 3D).

  17. The role of individual variation in marine larval dispersal

    KAUST Repository

    Nanninga, Gerrit B.

    2014-12-08

    The exchange of individuals among patchy habitats plays a central role in spatial ecology and metapopulation dynamics. Dispersal is frequently observed to vary non-randomly within populations (e.g., short vs. long), indicating that variability among individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape heterogeneity (the context) with phenotypic variability among individuals (the condition). While this hypothesis is widely accepted in terrestrial theory, it remains questionable to what extent the concept of adaptive dispersal strategies may apply to marine larval dispersal, a process that is largely determined by stochastic forces. Yet, larvae of many taxa exhibit strong navigational capabilities and there is mounting evidence of widespread intra-specific variability in biological traits that are potentially correlated with dispersal potential. While so far there are few known examples of real larval dispersal polymorphisms, intra-specifically variable dispersal strategies may be common in marine systems. Whether adaptive or not, it is becoming apparent that inter-individual heterogeneity in morphology, behavior, condition, and life history traits may have critical effects on population-level heterogeneity in dispersal. Here, we explore the eco-evolutionary causes and consequences of intrinsic and extrinsic variability on larval dispersal by synthesizing the existing literature and drawing conceptual parallels from terrestrial theory. We emphasize the potential importance of larval dispersal polymorphisms in marine population dynamics.

  18. Linear quantum optical bare raising operator

    Science.gov (United States)

    Radtke, Jennifer C. J.; Oi, Daniel K. L.; Jeffers, John

    2017-11-01

    We propose a simple implementation of the bare raising operator on coherent states via conditional measurement, which succeeds with high probability and fidelity. This operation works well not only on states with a Poissonian photon number distribution but also for a much wider class of states. As a part of this scheme, we highlight an experimentally testable effect in which a single photon is induced through a highly reflecting beamsplitter by a large amplitude coherent state, with probability 1/e(≈ 37 % ) in the limit of large coherent state amplitude.

  19. Embryonic, larval, and juvenile development of the sea biscuit Clypeaster subdepressus (Echinodermata: Clypeasteroida.

    Directory of Open Access Journals (Sweden)

    Bruno C Vellutini

    Full Text Available Sea biscuits and sand dollars diverged from other irregular echinoids approximately 55 million years ago and rapidly dispersed to oceans worldwide. A series of morphological changes were associated with the occupation of sand beds such as flattening of the body, shortening of primary spines, multiplication of podia, and retention of the lantern of Aristotle into adulthood. To investigate the developmental basis of such morphological changes we documented the ontogeny of Clypeaster subdepressus. We obtained gametes from adult specimens by KCl injection and raised the embryos at 26 degrees C. Ciliated blastulae hatched 7.5 h after sperm entry. During gastrulation the archenteron elongated continuously while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larvae began to feed in 3 d and were 20 d old at metamorphosis; starved larvae died 17 d after fertilization. Postlarval juveniles had neither mouth nor anus nor plates on the aboral side, except for the remnants of larval spicules, but their bilateral symmetry became evident after the resorption of larval tissues. Ossicles of the lantern were present and organized in 5 groups. Each group had 1 tooth, 2 demipyramids, and 2 epiphyses with a rotula in between. Early appendages consisted of 15 spines, 15 podia (2 types, and 5 sphaeridia. Podial types were distributed in accordance to Lovén's rule and the first podium of each ambulacrum was not encircled by the skeleton. Seven days after metamorphosis juveniles began to feed by rasping sand grains with the lantern. Juveniles survived in laboratory cultures for 9 months and died with wide, a single open sphaeridium per ambulacrum, aboral anus, and no differentiated food grooves or petaloids. Tracking the morphogenesis of early juveniles is a necessary step to elucidate the developmental mechanisms of echinoid growth and important groundwork to clarify homologies between irregular urchins.

  20. Effects of temperature and salinity on larval survival and development in the invasive shrimp Palaemon macrodactylus (Caridea: Palaemonidae) along the reproductive season

    Science.gov (United States)

    Guadalupe Vázquez, M.; Bas, Claudia C.; Kittlein, Marcelo; Spivak, Eduardo D.

    2015-05-01

    The invasive shrimp Palaemon macrodactylus is associated mainly with brackish waters. Previous studies raised the question if tolerance to low salinities differs between larvae and adults. To answer this question, the combined effects of two temperatures (20 and 25 °C) and four salinities (5, 12, 23 and 34 psu) on survival and development of larvae that hatched at the beginning, in the midpoint and near the end of a reproductive season (denoted early, middle season and late larvae respectively) were examined. The three types of larvae were able to survive and reach juvenile phase at salinities between 12 and 34 psu and at both temperatures. At 5 psu all larvae died, but 45% molted at least once. Temperature and salinity to a lesser extent, had effects on the duration of development and on the number of larval stages in all larval types. Development was longer at the lower temperature, especially in middle season and late larvae. Most early larvae reached the juvenile phase through 5 larval stages; the number of larval stages of middle season and late larvae was higher at 20 °C and in late larvae also low salinity produced extra stages. Low salinity (12 psu) and, in early and middle season larvae, low temperature produced lighter and smaller individuals. Response of larvae to environmental factors seems to be related in part to the previous conditions (maternal effects and/or embryo development conditions). The narrower salinity tolerance of larvae compared to adults and the ability of zoea I to survive at least some days at 5 psu may be related with an export larval strategy.

  1. Remotely Sensing Larval Population Dynamics of Rice Field Anophelines

    Science.gov (United States)

    Beck, Louisa R.; Dister, Sheri W.; Wood, Byron L.; Washino, Robert K.

    1997-01-01

    The primary objective of both studies was to determine if RS and GIS techniques could be used to distinguish between high and low larval-producing rice fields in California. Results of the first study suggested that early-season green-up and proximity to livestock pastures were positively correlated with high larval abundance. Based on the early-season spectral differences between high and low larval-producing fields, it appeared that canopy development and tillering influenced mosquito habitat quality. At that time, rice fields consisted of a mixture of plants and water, a combination that allowed An. freeborni females to lay eggs in partial sunlight, protected from both predators and wind. This established a population earlier in the season than in other, 'less-green' fields where tillering and plant emergence was too minimal for ovipositioning. The study also indicated the importance of the distance that a mosquito would have to fly in order to take a bloodmeal prior to ovipositing. These associations were fully explored in an expanded study two years later. The second study confirmed the positive relationship between early season canopy development and larval abundance, and also demonstrated the relationship between abundance and distance-to-pasture. The association between greenness (as measured using NDVI), distance-to-pasture, and abundance is illustrated. The second study also indicated the siginificance of the landscape context of rice fields for larval production. Fields that included opportunities for feeding and resting within the flight range of the mosquito had higher abundances than did fields that were in a homogeneous rice area.

  2. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi.

    Science.gov (United States)

    Vogels, Chantal B F; Bukhari, Tullu; Koenraadt, Constantianus J M

    2014-06-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible. Copyright © 2014. Published by Elsevier Inc.

  3. Food selection in larval fruit flies: dynamics and effects on larval development

    Science.gov (United States)

    Schwarz, Sebastian; Durisko, Zachary; Dukas, Reuven

    2014-01-01

    Selecting food items and attaining a nutritionally balanced diet is an important challenge for all animals including humans. We aimed to establish fruit fly larvae ( Drosophila melanogaster) as a simple yet powerful model system for examining the mechanisms of specific hunger and diet selection. In two lab experiments with artificial diets, we found that larvae deprived of either sucrose or protein later selectively fed on a diet providing the missing nutrient. When allowed to freely move between two adjacent food patches, larvae surprisingly preferred to settle on one patch containing yeast and ignored the patch providing sucrose. Moreover, when allowed to move freely between three patches, which provided either yeast only, sucrose only or a balanced mixture of yeast and sucrose, the majority of larvae settled on the yeast-plus-sucrose patch and about one third chose to feed on the yeast only food. While protein (yeast) is essential for development, we also quantified larval success on diets with or without sucrose and show that larvae develop faster on diets containing sucrose. Our data suggest that fruit fly larvae can quickly assess major nutrients in food and seek a diet providing a missing nutrient. The larvae, however, probably prefer to quickly dig into a single food substrate for enhanced protection over achieving an optimal diet.

  4. 29 CFR 780.123 - Raising of bees.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Raising of bees. 780.123 Section 780.123 Labor Regulations... Raising of Livestock, Bees, Fur-Bearing Animals, Or Poultry § 780.123 Raising of bees. The term “raising of * * * bees” refers to all of those activities customarily performed in connection with the...

  5. Immunocytochemistry and metamorphic fate of the larval nervous system of Triphyllozoon mucronatum (Ectoprocta: Gymnolaemata: Cheilostomata)

    DEFF Research Database (Denmark)

    Wanninger, Andreas; Koop, Demian; Degnan, Bernard M.

    2005-01-01

    The development of gymnolaemate Ectoprocta includes a larval stage of either the coronate or the cyphonautes type. Herein, we provide the first description of the larval neural anatomy of a coronate larva using immunocytochemical methods. We used antibodies against the neurotransmitters serotonin...... that the larval neuroanatomy and the processes that underlie the reorganization of larval organ systems during metamorphosis may vary much more among lophotrochozoan taxa than previously thought....... and FMRFamide and followed the fate of immunoreactive cells through metamorphosis. The larval serotonergic nervous system of Triphyllozoon mucronatum consists of an apical commissure, one pair of lateral axons, a coronate nerve net, an internal nerve mesh, and one pair of axons innervating the frontal organ....... FMRFamide is only found in the larval commissure and in the lateral axons. The entire serotonergic and FMRFamidergic nervous system is lost during metamorphosis and the adult neural structures form independent of the larval ones. In the postlarval zooid, both neurotransmitters are detected in the cerebral...

  6. Raising the standards of the calf-raise test: a systematic review.

    Science.gov (United States)

    Hébert-Losier, Kim; Newsham-West, Richard J; Schneiders, Anthony G; Sullivan, S John

    2009-11-01

    The calf-raise test is used by clinicians and researchers in sports medicine to assess properties of the calf muscle-tendon unit. The test generally involves repetitive concentric-eccentric muscle action of the plantar-flexors in unipedal stance and is quantified by the number of raises performed. Although the calf-raise test appears to have acceptable reliability and face validity, and is commonly used for medical assessment and rehabilitation of injuries, no universally acceptable test parameters have been published to date. A systematic review of the existing literature was conducted to investigate the consistency as well as universal acceptance of the evaluation purposes, test parameters, outcome measurements and psychometric properties of the calf-raise test. Nine electronic databases were searched during the period May 30th to September 21st 2008. Forty-nine articles met the inclusion criteria and were quality assessed. Information on study characteristics and calf-raise test parameters, as well as quantitative data, were extracted; tabulated; and statistically analysed. The average quality score of the reviewed articles was 70.4+/-12.2% (range 44-90%). Articles provided various test parameters; however, a consensus was not ascertained. Key testing parameters varied, were often unstated, and few studies reported reliability or validity values, including sensitivity and specificity. No definitive normative values could be established and the utility of the test in subjects with pathologies remained unclear. Although adapted for use in several disciplines and traditionally recommended for clinical assessment, there is no uniform description of the calf-raise test in the literature. Further investigation is recommended to ensure consistent use and interpretation of the test by researchers and clinicians.

  7. Against Raising Hope of Raising the Dead: Contra Moody and Kubler-Ross.

    Science.gov (United States)

    Vicchio, Stephen J.; And Others

    1979-01-01

    Kubler-Ross and Moody have made assertions about survival after death. They argued that the subjects were not dead, but in the process of dying. An alternative explanation to this "glimpse of the afterlife" approach is offered. Other theological objections are raised to the Moody/Kubler-Ross approach. (Author)

  8. Effects of moisture content of food waste on residue separation, larval growth and larval survival in black soldier fly bioconversion.

    Science.gov (United States)

    Cheng, Jack Y K; Chiu, Sam L H; Lo, Irene M C

    2017-09-01

    In order to foster sustainable management of food waste, innovations in food waste valorization technologies are crucial. Black soldier fly (BSF) bioconversion is an emerging technology that can turn food waste into high-protein fish feed through the use of BSF larvae. The conventional method of BSF bioconversion is to feed BSF larvae with food waste directly without any moisture adjustment. However, it was reported that difficulty has been experienced in the separation of the residue (larval excreta and undigested material) from the insect biomass due to excessive moisture. In addition to the residue separation problem, the moisture content of the food waste may also affect the growth and survival aspects of BSF larvae. This study aims to determine the most suitable moisture content of food waste that can improve residue separation as well as evaluate the effects of the moisture content of food waste on larval growth and survival. In this study, pre-consumer and post-consumer food waste with different moisture content (70%, 75% and 80%) was fed to BSF larvae in a temperature-controlled rotary drum reactor. The results show that the residue can be effectively separated from the insect biomass by sieving using a 2.36mm sieve, for both types of food waste at 70% and 75% moisture content. However, sieving of the residue was not feasible for food waste at 80% moisture content. On the other hand, reduced moisture content of food waste was found to slow down larval growth. Hence, there is a trade-off between the sieving efficiency of the residue and the larval growth rate. Furthermore, the larval survival rate was not affected by the moisture content of food waste. A high larval survival rate of at least 95% was achieved using a temperature-controlled rotary drum reactor for all treatment groups. The study provides valuable insights for the waste management industry on understanding the effects of moisture content when employing BSF bioconversion for food waste recycling

  9. Social coercion of larval development in an ant species.

    Science.gov (United States)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  10. Social coercion of larval development in an ant species

    Science.gov (United States)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  11. Rapid effects of marine reserves via larval dispersal.

    Directory of Open Access Journals (Sweden)

    Richard Cudney-Bueno

    Full Text Available Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs, with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

  12. The effects of food level and conspecific density on biting and cannibalism in larval long-toed salamanders, Ambystoma macrodactylum.

    Science.gov (United States)

    Wildy, Erica L; Chivers, Douglas P; Kiesecker, Joseph M; Blaustein, Andrew R

    2001-07-01

    Previous studies have examined abiotic and biotic factors that facilitate agonistic behavior. For larval amphibians, food availability and conspecific density have been suggested as important factors influencing intraspecific aggression and cannibalism. In this study, we examined the separate and combined effects of food availability and density on the agonistic behavior and life history of larval long-toed salamanders, Ambystoma macrodactylum. We designed a 2×2 factorial experiment in which larvae were raised with either a high or low density of conspecifics and fed either a high or low level of food. For each treatment, we quantified the amount of group size variation, biting, and cannibalism occurring. Additionally, we examined survival to, time to and size at metamorphosis for all larvae. Results indicated that differences in both density and food level influenced all three life history traits measured. Moreover, differences in food level at which larvae were reared resulted in higher within-group size variation and heightened intraspecific biting while both density and food level contributed to increased cannibalism. We suggest that increased hunger levels and an uneven size structure promoted biting among larvae in the low food treatments. Moreover, these factors combined with a higher encounter rate with conspecifics in the high density treatments may have prompted larger individuals to seek an alternative food source in the form of smaller conspecifics.

  13. Characterisation of Culex quinquefasciatus (Diptera: Culicidae larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Marta Grech

    2013-09-01

    Full Text Available The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase.

  14. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    Energy Technology Data Exchange (ETDEWEB)

    McKinley, Andrew C., E-mail: andrew.mckinley@hotmail.com [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia); Miskiewicz, Anthony [Environment and Recreation, Wollongong City Council, 41 Burelli Street, Wollongong, New South Wales 2500 (Australia); Taylor, Matthew D.; Johnston, Emma L. [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia)

    2011-06-15

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: > We examine contamination/habitat modification impacts on larval fish. > Larvae communities differ between modified/unmodified estuaries. > Larvae are more abundant/diverse in modified areas. > Trends are strongly related to sediment metals/seagrass cover. > Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

  15. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    International Nuclear Information System (INIS)

    McKinley, Andrew C.; Miskiewicz, Anthony; Taylor, Matthew D.; Johnston, Emma L.

    2011-01-01

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: → We examine contamination/habitat modification impacts on larval fish. → Larvae communities differ between modified/unmodified estuaries. → Larvae are more abundant/diverse in modified areas. → Trends are strongly related to sediment metals/seagrass cover. → Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

  16. Evolution of increased adult longevity in Drosophila melanogaster populations selected for adaptation to larval crowding.

    Science.gov (United States)

    Shenoi, V N; Ali, S Z; Prasad, N G

    2016-02-01

    In holometabolous animals such as Drosophila melanogaster, larval crowding can affect a wide range of larval and adult traits. Adults emerging from high larval density cultures have smaller body size and increased mean life span compared to flies emerging from low larval density cultures. Therefore, adaptation to larval crowding could potentially affect adult longevity as a correlated response. We addressed this issue by studying a set of large, outbred populations of D. melanogaster, experimentally evolved for adaptation to larval crowding for 83 generations. We assayed longevity of adult flies from both selected (MCUs) and control populations (MBs) after growing them at different larval densities. We found that MCUs have evolved increased mean longevity compared to MBs at all larval densities. The interaction between selection regime and larval density was not significant, indicating that the density dependence of mean longevity had not evolved in the MCU populations. The increase in longevity in MCUs can be partially attributed to their lower rates of ageing. It is also noteworthy that reaction norm of dry body weight, a trait probably under direct selection in our populations, has indeed evolved in MCU populations. To the best of our knowledge, this is the first report of the evolution of adult longevity as a correlated response of adaptation to larval crowding. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  17. Efficiency of selection methods for increased ratio of pupal-larval to adult-larval weight gains in Tribolium.

    Science.gov (United States)

    Campo, J L; Cobos, P

    1994-01-12

    Four lines of Tribolium castaneum were selected in each of three replicates for increased ratio of (pupal-larval) to (adult-larval) weight gains, using selection for increased (pupal-larval) weight gain (PL), selection for decreased (adult-larval) weight gain (AL), direct selection for the ratio (R) and linear selection index of larval, pupal and adult weights (I), respectively, for four generations. Linear index was calculated with economic weights of m(2) -m(3) , m(3) -m(1) and m(1) -m(2) , respectively, with m(1) , m(2) and m(3) being the means for larval, pupal and adult weights. Selection to increase the ratio is considered to be a method to maximize the mean response in (adult-larval) weight while controlling the response in (pupal-adult) weight, and as a form of antagonistic selection to increase the weight gain during a given age period relative to the gain at another age period. Larval, pupal and adult weights were measured at 14, 21 and 28 days after adult emergence, respectively. The selected proportion was 20 % in all lines. The response observed for the ratio differed significantly among lines (p adulto-peso de larva en Tribolium Cuatro líneas de Tribolium castaneum fueron seleccionadas en cada una de tres repeticiones para incrementar el cociente (peso de pupa-peso de larva)/(peso de adulto-peso de larva); la línea PL fue seleccionada para aumentar la diferencia (peso de pupa-pesp de larva), la línea AL fue seleccionada para disminuir la diferencia (peso de adulto-peso de larva), fa línea R fue seleccionada directamente para el cociente, y la línea I fue seleccionada por medio de un índice lineal basado en los pesos de larva, pupa y adulto, durante cuatro generaciones. El índice lineal se calculó con pesos económicos de (m(2) -m(3) ), (m(3) -m(1) ), y (m(1) -m(2) ) respectivamentee, siendo m(1) , m(2) , y m(3) los valores medios para el peso de larva, pupa y adulto. La selección para aumentar el cociente indicado es un método para maximizar

  18. Protein and carbohydrate composition of larval food affects tolerance tothermal stress and desiccation in adult Drosophila melanogaster

    DEFF Research Database (Denmark)

    Andersen, Laila H; Kristensen, Torsten N; Loeschcke, Volker

    2010-01-01

    stress compared to males. Egg production was highest in females that had developed on the protein-enriched medium. However, there was a sex-specific effect of nutrition on egg-to-adult viability, with higher viability for males developing on the sucrose-enriched medium, while female survival was highest......Larval nutrition may affect a range of different life history traits as well as responses to environmental stress in adult insects. Here we test whether raising larvae of fruit flies, Drosophila melanogaster, on two different nutritional regimes affects resistance to cold, heat and desiccation....... In contrast, flies developed on the carbohydrate-enriched growth medium recovered faster from chill coma stress compared to flies developed on a protein-enriched medium. We also found gender differences in stress tolerance, with female flies being more tolerant to chill coma, heat knockdown and desiccation...

  19. Isolation and culture of larval cells from C. elegans.

    Directory of Open Access Journals (Sweden)

    Sihui Zhang

    Full Text Available Cell culture is an essential tool to study cell function. In C. elegans the ability to isolate and culture cells has been limited to embryonically derived cells. However, cells or blastomeres isolated from mixed stage embryos terminally differentiate within 24 hours of culture, thus precluding post-embryonic stage cell culture. We have developed an efficient and technically simple method for large-scale isolation and primary culture of larval-stage cells. We have optimized the treatment to maximize cell number and minimize cell death for each of the four larval stages. We obtained up to 7.8×10(4 cells per microliter of packed larvae, and up to 97% of adherent cells isolated by this method were viable for at least 16 hours. Cultured larval cells showed stage-specific increases in both cell size and multinuclearity and expressed lineage- and cell type-specific reporters. The majority (81% of larval cells isolated by our method were muscle cells that exhibited stage-specific phenotypes. L1 muscle cells developed 1 to 2 wide cytoplasmic processes, while L4 muscle cells developed 4 to 14 processes of various thicknesses. L4 muscle cells developed bands of myosin heavy chain A thick filaments at the cell center and spontaneously contracted ex vivo. Neurons constituted less than 10% of the isolated cells and the majority of neurons developed one or more long, microtubule-rich protrusions that terminated in actin-rich growth cones. In addition to cells such as muscle and neuron that are high abundance in vivo, we were also able to isolate M-lineage cells that constitute less than 0.2% of cells in vivo. Our novel method of cell isolation extends C. elegans cell culture to larval developmental stages, and allows use of the wealth of cell culture tools, such as cell sorting, electrophysiology, co-culture, and high-resolution imaging of subcellular dynamics, in investigation of post-embryonic development and physiology.

  20. 29 CFR 780.616 - Operations included in raising livestock.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Operations included in raising livestock. 780.616 Section... Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption Requirements for Exemption § 780.616 Operations included in raising livestock. Raising livestock includes such...

  1. RAISED BOGS ON THE NORTH-EAST OF EUROPE

    Directory of Open Access Journals (Sweden)

    T. K. YURKOVSKAYA

    2004-01-01

    Full Text Available In the Northeastern Europe 2 types of raised bogs are distinguished: coastal (Southern White Sea raised hogs and continental (Pechora-Onega raised bogs. They have been compared as to their flora, prevailing syntaxa, characteristics of their complexes, structure of mire massifs and composition of peat deposits.

  2. 29 CFR 780.126 - Contract arrangements for raising poultry.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Contract arrangements for raising poultry. 780.126 Section... General Scope of Agriculture Raising of Livestock, Bees, Fur-Bearing Animals, Or Poultry § 780.126 Contract arrangements for raising poultry. Feed dealers and processors sometimes enter into contractual...

  3. The Campus Green: Fund Raising in Higher Education. ERIC Digest.

    Science.gov (United States)

    Brittingham, Barbara E.; Pezzullo, Thomas R.

    This digest summarizes issues raised in a research report on fund raising in higher education. The following questions are addressed: What are the changes and trends since the early days of educational fund raising? What are the implications? What is known about spending? What is known about donor behavior? What are the major ethical issues? What…

  4. Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

    Directory of Open Access Journals (Sweden)

    Megan J Donahue

    Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

  5. Redescription of the early larval stages of the pandalid shrimp Chlorotocus crassicornis (Decapoda: Caridea: Pandalidae).

    Science.gov (United States)

    Landeira, Jose M; Jiang, Guo-Chen; Chan, Tin-Yam; Shih, Tung-Wei; Gozález-Gordillo, J Ignacio

    2015-09-07

    The first four larval stages of the pandalid shrimp Chlorotocus crassicornis (A. Costa, 1871) are described and illustrated from laboratory-reared material obtained from ovigerous females collected in the southwestern Spain and south Taiwan. The second to fourth larval stages of this species are reported for the first time to science. Detailed examination of the first larval stages reveals that previous description misidentified some key larval characters which have prevented its identification in plankton samples. It is found that the zoeal morphology of Chlorotocus is not very different from other pandalid larvae, and in fact closely resembles Plesionika and Heterocarpus.

  6. Raising Crop Productivity in Africa through Intensification

    Directory of Open Access Journals (Sweden)

    Zerihun Tadele

    2017-03-01

    Full Text Available The population of Africa will double in the next 33 years to reach 2.5 billion by 2050. Although roughly 60% of the continent’s population is engaged in agriculture, the produce from this sector cannot feed its citizens. Hence, in 2013 alone, Africa imported 56.5 million tons of wheat, maize, and soybean at the cost of 18.8 billion USD. Although crops cultivated in Africa play a vital role in their contribution to Food Security, they produce inferior yields compared to those in other parts of the world. For instance, the average cereal yield in Africa is only 1.6 t·ha−1 compared to the global 3.9 t·ha−1. Low productivity in Africa is also related to poor soil fertility and scarce moisture, as well as a variety of insect pests, diseases, and weeds. While moisture scarcity is responsible for up to 60% of yield losses in some African staple cereals, insect pests inflict annually substantial crop losses. In order to devise a strategy towards boosting crop productivity on the continent where food insecurity is most prevalent, these production constraints should be investigated and properly addressed. This review focuses on conventional (also known as genetic intensification in which crop productivity is raised through breeding for cultivars with high yield-potential and those that thrive well under diverse and extreme environmental conditions. Improved crop varieties alone do not boost crop productivity unless supplemented with optimum soil, water, and plant management practices as well as the promotion of policies pertaining to inputs, credit, extension, and marketing. Studies in Kenya and Uganda have shown that the yield of cassava can be increased by 140% in farmers’ fields using improved varieties and management practices. In addition to traditional organic and inorganic fertilizers, biochar and African Dark Earths have been found to improve soil properties and to enhance productivity, although their availability and affordability to

  7. Parasites of larval black flies (Diptera: Simuliidae in Thailand

    Directory of Open Access Journals (Sweden)

    Sanae Jitklang

    2012-12-01

    Full Text Available Parasites of larval black flies are reported for the first time from Thailand, including mermithid nematodes(Mermithidae, microsporidian fungi (Zygomycota, and the fungus Coelomycidium simulii Debaisieux (Blastocladiomycetes.The following nine species of black flies were infected with one or more parasites: Simulium asakoae, S. chamlongi,S. chiangmaiense, S. fenestratum, S. feuerborni, S. nakhonense, S. nodosum, S. quinquestriatum, and S. tani. The prevalenceof patent infections per host species per season was 0.1–7.1% for mermithids, 0.1–6.0% for microsporidia, and 0.1–3.0% forC. simulii.

  8. Embryonic and larval development in barfin flounder Verasper moseri (Jordan and Gilbert)

    Science.gov (United States)

    Du, Rongbin; Wang, Yongqiang; Jiang, Haibin; Liu, Liming; Wang, Maojian; Li, Tianbao; Zhang, Shubao

    2010-01-01

    Broodstock of Verasper moseri (Jordan and Gilbert) aged 3-4 years old were selected, and reinforced cultivation was conducted to promote maturation under controlled water temperature and photoperiod conditions. Fertilized eggs were obtained by artificial fertilization, and the development of embryos, larvae and juveniles was observed continuously. The results showed that the fertilized eggs of V. moseri were spherical, with transparent yolk and homogeneous bioplasm, and had no oil globule inside. The average diameter of the eggs was 1.77±0.02 mm. The eggs of V. moseri were buoyant in water with salinity above 35. The cleavage type was typical discoidal. Young pigment cells appeared when olfactory plates began to form. Hatching occurred at 187 h after fertilization at a water temperature of 8.5°C. The newly hatched larvae, floating on the water surface, were transparent with an average total length of 4.69±0.15 mm. During the cultivation period, when the water temperature was raised from 9 to 14.5°C, 4-day old larvae showed more melanophores on the body surface, making the larvae gray in color. The pectoral fins began to develop, which enabled the larvae to swim horizontally and in a lively manner. On days 7-8, the digestive duct formed. The yolk sac was small and black. The yolk sac was absorbed on day 11. Larvae took food actively, and body length and body height clearly increased. The rudiments of dorsal and anal fin pterygiophores were discernible and caudal fin ray elements formed on day 19. On day 24, the larval notochord flexed upwards, and the rays of unpaired fins began to differentiate. Pigment cells converged on the dorsal and anal fin rays, and the mastoid teeth on the mandible appeared. On day 29, the left eyes of juveniles began to move upwards. Depigmentation began in some juveniles and they became sandy brown in color on day 37. Most juveniles began to settle on the bottom of the tank. The left eyes of juveniles migrated completely to the right

  9. Effect of Larval Density on Food Utilization Efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae).

    Science.gov (United States)

    Morales-Ramos, Juan A; Rojas, M Guadalupe

    2015-10-01

    Crowding conditions of larvae may have a significant impact on commercial production efficiency of some insects, such as Tenebrio molitor L. (Coleoptera: Tenebrionidae). Although larval densities are known to affect developmental time and growth in T. molitor, no reports were found on the effects of crowding on food utilization. The effect of larval density on food utilization efficiency of T. molitor larvae was studied by measuring efficiency of ingested food conversion (ECI), efficiency of digested food conversion (EDC), and mg of larval weight gain per gram of food consumed (LWGpFC) at increasing larval densities (12, 24, 36, 48, 50, 62, 74, and 96 larvae per dm(2)) over four consecutive 3-wk periods. Individual larval weight gain and food consumption were negatively impacted by larval density. Similarly, ECI, ECD, and LWGpFC were negatively impacted by larval density. Larval ageing, measured as four consecutive 3-wk periods, significantly and independently impacted ECI, ECD, and LWGpFC in a negative way. General linear model analysis showed that age had a higher impact than density on food utilization parameters of T. molitor larvae. Larval growth was determined to be responsible for the age effects, as measurements of larval mass density (in grams of larvae per dm(2)) had a significant impact on food utilization parameters across ages and density treatments (in number of larvae per dm(2)). The importance of mass versus numbers per unit of area as measurements of larval density and the implications of negative effects of density on food utilization for insect biomass production are discussed. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  10. Lipid Uptake, Metabolism, and Transport in the Larval Zebrafish

    Directory of Open Access Journals (Sweden)

    Vanessa H. Quinlivan

    2017-11-01

    Full Text Available The developing zebrafish is a well-established model system for studies of energy metabolism, and is amenable to genetic, physiological, and biochemical approaches. For the first 5 days of life, nutrients are absorbed from its endogenous maternally deposited yolk. At 5 days post-fertilization, the yolk is exhausted and the larva has a functional digestive system including intestine, liver, gallbladder, pancreas, and intestinal microbiota. The transparency of the larval zebrafish, and the genetic and physiological similarity of its digestive system to that of mammals make it a promising system in which to address questions of energy homeostasis relevant to human health. For example, apolipoprotein expression and function is similar in zebrafish and mammals, and transgenic animals may be used to examine both the transport of lipid from yolk to body in the embryo, and the trafficking of dietary lipids in the larva. Additionally, despite the identification of many fatty acid and lipid transport proteins expressed by vertebrates, the cell biological processes that mediate the transport of dietary lipids from the intestinal lumen to the interior of enterocytes remain to be elucidated. Genetic tractability and amenability to live imaging and a range of biochemical methods make the larval zebrafish an ideal model in which to address open questions in the field of lipid transport, energy homeostasis, and nutrient metabolism.

  11. Olfactory memories are intensity specific in larval Drosophila.

    Science.gov (United States)

    Mishra, Dushyant; Chen, Yi-Chun; Yarali, Ayse; Oguz, Tuba; Gerber, Bertram

    2013-05-01

    Learning can rely on stimulus quality, stimulus intensity, or a combination of these. Regarding olfaction, the coding of odour quality is often proposed to be combinatorial along the olfactory pathway, and working hypotheses are available concerning short-term associative memory trace formation of odour quality. However, it is less clear how odour intensity is coded, and whether olfactory memory traces include information about the intensity of the learnt odour. Using odour-sugar associative conditioning in larval Drosophila, we first describe the dose-effect curves of learnability across odour intensities for four different odours (n-amyl acetate, 3-octanol, 1-octen-3-ol and benzaldehyde). We then chose odour intensities such that larvae were trained at an intermediate odour intensity, but were tested for retention with either that trained intermediate odour intensity, or with respectively higher or lower intensities. We observed a specificity of retention for the trained intensity for all four odours used. This adds to the appreciation of the richness in 'content' of olfactory short-term memory traces, even in a system as simple as larval Drosophila, and to define the demands on computational models of associative olfactory memory trace formation. We suggest two kinds of circuit architecture that have the potential to accommodate intensity learning, and discuss how they may be implemented in the insect brain.

  12. Larval fish dispersal in a coral-reef seascape

    KAUST Repository

    Almany, Glenn R.

    2017-05-23

    Larval dispersal is a critical yet enigmatic process in the persistence and productivity of marine metapopulations. Empirical data on larval dispersal remain scarce, hindering the use of spatial management tools in efforts to sustain ocean biodiversity and fisheries. Here we document dispersal among subpopulations of clownfish (Amphiprion percula) and butterflyfish (Chaetodon vagabundus) from eight sites across a large seascape (10,000 km2) in Papua New Guinea across 2 years. Dispersal of clownfish was consistent between years, with mean observed dispersal distances of 15 km and 10 km in 2009 and 2011, respectively. A Laplacian statistical distribution (the dispersal kernel) predicted a mean dispersal distance of 13–19 km, with 90% of settlement occurring within 31–43 km. Mean dispersal distances were considerably greater (43–64 km) for butterflyfish, with kernels declining only gradually from spawning locations. We demonstrate that dispersal can be measured on spatial scales sufficient to inform the design of and test the performance of marine reserve networks.

  13. The influence of substrate material on ascidian larval settlement.

    Science.gov (United States)

    Chase, Anna L; Dijkstra, Jennifer A; Harris, Larry G

    2016-05-15

    Submerged man-made structures present novel habitat for marine organisms and often host communities that differ from those on natural substrates. Although many factors are known to contribute to these differences, few studies have directly examined the influence of substrate material on organism settlement. We quantified larval substrate preferences of two species of ascidians, Ciona intestinalis (cryptogenic, formerly C. intestinalis type B) and Botrylloides violaceus (non-native), on commonly occurring natural (granite) and man-made (concrete, high-density polyethylene, PVC) marine materials in laboratory trials. Larvae exhibited species-specific settlement preferences, but generally settled more often than expected by chance on concrete and HDPE. Variation in settlement between materials may reflect preferences for rougher substrates, or may result from the influence of leached chemicals on ascidian settlement. These findings indicate that an experimental plate material can influence larval behavior and may help us understand how substrate features may contribute to differences in settlement in the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Larval fish dispersal in a coral-reef seascape

    KAUST Repository

    Almany, Glenn R.; Planes, Serge; Thorrold, Simon R.; Berumen, Michael L.; Bode, Michael; Saenz Agudelo, Pablo; Bonin, Mary C.; Frisch, Ashley J.; Harrison, Hugo B.; Messmer, Vanessa; Nanninga, Gerrit B.; Priest, Mark; Srinivasan, Maya; Sinclair-Taylor, Tane; Williamson, David H.; Jones, Geoffrey P.

    2017-01-01

    Larval dispersal is a critical yet enigmatic process in the persistence and productivity of marine metapopulations. Empirical data on larval dispersal remain scarce, hindering the use of spatial management tools in efforts to sustain ocean biodiversity and fisheries. Here we document dispersal among subpopulations of clownfish (Amphiprion percula) and butterflyfish (Chaetodon vagabundus) from eight sites across a large seascape (10,000 km2) in Papua New Guinea across 2 years. Dispersal of clownfish was consistent between years, with mean observed dispersal distances of 15 km and 10 km in 2009 and 2011, respectively. A Laplacian statistical distribution (the dispersal kernel) predicted a mean dispersal distance of 13–19 km, with 90% of settlement occurring within 31–43 km. Mean dispersal distances were considerably greater (43–64 km) for butterflyfish, with kernels declining only gradually from spawning locations. We demonstrate that dispersal can be measured on spatial scales sufficient to inform the design of and test the performance of marine reserve networks.

  15. Mosquito population regulation and larval source management in heterogeneous environments.

    Directory of Open Access Journals (Sweden)

    David L Smith

    Full Text Available An important question for mosquito population dynamics, mosquito-borne pathogen transmission and vector control is how mosquito populations are regulated. Here we develop simple models with heterogeneity in egg laying patterns and in the responses of larval populations to crowding in aquatic habitats. We use the models to evaluate how such heterogeneity affects mosquito population regulation and the effects of larval source management (LSM. We revisit the notion of a carrying capacity and show how heterogeneity changes our understanding of density dependence and the outcome of LSM. Crowding in and productivity of aquatic habitats is highly uneven unless egg-laying distributions are fine-tuned to match the distribution of habitats' carrying capacities. LSM reduces mosquito population density linearly with coverage if adult mosquitoes avoid laying eggs in treated habitats, but quadratically if eggs are laid in treated habitats and the effort is therefore wasted (i.e., treating 50% of habitat reduces mosquito density by approximately 75%. Unsurprisingly, targeting (i.e. treating a subset of the most productive pools gives much larger reductions for similar coverage, but with poor targeting, increasing coverage could increase adult mosquito population densities if eggs are laid in higher capacity habitats. Our analysis suggests that, in some contexts, LSM models that accounts for heterogeneity in production of adult mosquitoes provide theoretical support for pursuing mosquito-borne disease prevention through strategic and repeated application of modern larvicides.

  16. Effect of propolis extract on angelfish larval performance and transport

    Directory of Open Access Journals (Sweden)

    Douglas da Cruz Mattos

    2017-06-01

    Full Text Available This study aimed to evaluate the influence propolis extract inclusion to the feed mixture for juvenile angelfish (Pterophyllum scalare on larval performance and transport. Levels of propolis extract inclusion consisted of 0, 300, 600, 900, and 1200 mg.kg-1 of feed. After 14 days of hatching, unmetamorphosed larvae with a total length of 18.4 mm and 0.11 g initial weight were used. Six-hundred larvae were divided into 20 experimental units, totalizing 30 larvae each. Experimental units consisted of polythene containers with independent water input and output and a level controller. Each unit was controlled for maintenance of 40 L water within a recirculation system. After offering feed containing propolis extract, five fish from each experimental unit were packed in bags for transportation only with atmospheric air, without pure oxygen addition. The bags were filled with 300 mL water on a 2:1 basis of air and water respectively. The total transport time was considered until the death of the third fish in package. At the end of the experiment, data underwent statistical analysis through Statistical Analysis System (SAS, 2001. Results showed there was no significant difference (P < 0.05 neither for any of the studied zootechnical variables (standard length, total length, height, and weight nor for the transport of juveniles. In conclusion, propolis extract addition to angelfish feed was ineffective for larval performance and for transportation of juveniles, at the levels tested here.

  17. Small nonnative fishes as predators of larval razorback suckers

    Science.gov (United States)

    Carpenter, J.; Mueller, G.A.

    2008-01-01

    The razorback sucker (Xyrauchen texanus), an endangered big-river fish of the Colorado River basin, has demonstrated no sustainable recruitment in 4 decades, despite presence of spawning adults and larvae. Lack of adequate recruitment has been attributed to several factors, including predation by nonnative fishes. Substantial funding and effort has been expended on mechanically removing nonnative game fishes, typically targeting large predators. As a result, abundance of larger predators has declined, but the abundance of small nonnative fishes has increased in some areas. We conducted laboratory experiments to determine if small nonnative fishes would consume larval razorback suckers. We tested adults of three small species (threadfin shad, Dorosoma petenense; red shiner, Cyprinella lutrensis; fathead minnow, Pimephales promelas) and juveniles of six larger species (common carp, Cyprinus carpio; yellow bullhead, Ameiurus natalis; channel catfish, Ictalurus punctatus; rainbow trout, Oncorhynchus mykiss; green sunfish, Lepomis cyanellus; bluegill, L. macrochirus). These nonnative fishes span a broad ecological range and are abundant within the historical range of the razorback sucker. All nine species fed on larval razorback suckers (total length, 9-16 mm). Our results suggest that predation by small nonnative fishes could be responsible for limiting recovery of this endangered species.

  18. Resource Limitation, Controphic Ostracod Density and Larval Mosquito Development.

    Directory of Open Access Journals (Sweden)

    Raylea Rowbottom

    Full Text Available Aquatic environments can be restricted with the amount of available food resources especially with changes to both abiotic and biotic conditions. Mosquito larvae, in particular, are sensitive to changes in food resources. Resource limitation through inter-, and intra-specific competition among mosquitoes are known to affect both their development and survival. However, much less is understood about the effects of non-culicid controphic competitors (species that share the same trophic level. To address this knowledge gap, we investigated and compared mosquito larval development, survival and adult size in two experiments, one with different densities of non-culicid controphic conditions and the other with altered resource conditions. We used Aedes camptorhynchus, a salt marsh breeding mosquito and a prominent vector for Ross River virus in Australia. Aedes camptorhynchus usually has few competitors due to its halo-tolerance and distribution in salt marshes. However, sympatric ostracod micro-crustaceans often co-occur within these salt marshes and can be found in dense populations, with field evidence suggesting exploitative competition for resources. Our experiments demonstrate resource limiting conditions caused significant increases in mosquito developmental times, decreased adult survival and decreased adult size. Overall, non-culicid exploitation experiments showed little effect on larval development and survival, but similar effects on adult size. We suggest that the alterations of adult traits owing to non-culicid controphic competition has potential to extend to vector-borne disease transmission.

  19. Raising with long boreholes in Uranium Mines, Hamr

    International Nuclear Information System (INIS)

    Kubista, A.; Svoboda, M.; Mohyla, Z.

    1984-01-01

    The technology is described of raising with long boreholes which was used in uranium mines for breaking 15 raises to the end of 1983. Also described is the method of computing the needed charge. The described technology has the following advantages as compared with usual driving methods: 1. it secures greater work safety, 2. it allows driving atypical profiles, 3. smooth breaking secures good stability and longer life of raises, 4. allows higher productivity, 5. reduces capital costs. (Ha)

  20. Numerical simulations of barnacle larval dispersion coupled with field observations on larval abundance, settlement and recruitment in a tropical monsoon influenced coastal marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Samiksha S.V.; George, G.; Aboobacker V.M.; Vethamony, P.; Anil, A.C.

    Observations were carried out to monitor the larval abundance, settlement and recruitment of barnacles on a regular basis for a period of two years. The results were then compared with the numerical modelling studies carried out along the west coast...

  1. Larval connectivity studies in the Western Iberian Peninsula

    Science.gov (United States)

    Dubert, Jesus; Nolasco, Rita; Queiroga, Henrique

    2010-05-01

    The study of the connectivity between populations is one of the 'hot' applications of numerical models of the ocean circulation. An IBM (Individual Based model) was developed, using Carcinus manenas larvae crab as a model. A set of particles was used as a representation of larvae, in order to study their larval life cycle, including the larval growth, larval mortality (both depending on temperature and salinity), larval dispersal by currents, diel vertical migration, and larval recruitment. The life cycle of every larvae in the ocean, was modeled from zoeae 1 stage to megalopae stage, during typical periods of 30-50 days. Larvae were initialized in 14 estuarine systems of the Atlantic Western Iberian Peninsula, from January to July. In every period, a number of 225 larvae are initialized in everyone of the 14 considered estuaries, with fortynighly periodicity. The larvae evolves during the (variable, depending mainly on temperature) period of growth in the ocean, and when a larvae reach the age for recruit, if it is located in the neighborhood of the considered estuarine systems, the larvae is accounted as a recruited larvae in that place. With this methodology, a connectivity matrix can be computed, acconting for the 225 larvae emitted in every estuary, the number of larvae that reaches the every place. The connectivity matrix depends strongly on the current regime along the Atlantic coast of Iberian Peninsula, and has been calculated for the present circulation, for the period 2001 to 2009, for runs with realistic forcing with NCEP2 and Quikscat (for winds) forcing. The connectivity matrix, have also been calculated for climatological runs. For the present climatological conditions, it is observed the prevalence of southward transport for the period January-July, because the prevalence of Northerly winds along the west coast of IP in the COADS present time climatology. Strong dispersal is observed at the Northern estuaries, during winter with strong loss of

  2. Key technologies of drilling process with raise boring method

    Directory of Open Access Journals (Sweden)

    Zhiqiang Liu

    2015-08-01

    Full Text Available This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are described. The components of a raise boring machine including the drill rig, the drill string and the auxiliary system are also presented. Based on the analysis of the raise boring method, the rock mechanics problems during the raise boring process are put forward, including rock fragmentation, removal of cuttings, shaft wall stability, and borehole deviation control. Finally, the development trends of raise boring technology are described as follows: (i improvement of rock-breaking modes to raise drilling efficiency, (ii development of an intelligent control technique, and (iii development of technology and equipment for nonlinear raise boring.

  3. Penaeid prawns in the St Lucia Lake System: Post-larval recruitment ...

    African Journals Online (AJOL)

    Penaeid prawns in the St Lucia Lake System: Post-larval recruitment and the bait fishery. ... Recruitment of post-larval penaeid prawns and the bait prawn fishery in the St Lucia Lake System were monitored for ... AJOL African Journals Online.

  4. Experimental studies on the larval development of the shrimps Crangon crangon and C. allmanni

    Science.gov (United States)

    Criales, M. M.; Anger, K.

    1986-09-01

    Larvae of the shrimps Crangon crangon L. and C. allmanni Kinahan were reared in the laboratory from hatching through metamorphosis. Effects of rearing methods (larval density, application of streptomycin, food) and of salinity on larval development were tested only in C. crangon, influence of temperature was studied in both species. Best results were obtained when larvae were reared individually, with a mixture of Artemia sp. and the rotifer Brachionus plicatilis as food. Streptomycin had partly negative effects and was thus not adopted for standard rearing techniques. All factors tested in this study influenced not only the rates of larval survival and moulting, but also morphogenesis. In both species, in particular in C. crangon, a high degree of variability in larval morphology and in developmental pathways was observed. Unsuitable conditions, e.g. crowding in mass culture, application of antibiotics, unsuitable food (rotifers, phytoplankton), extreme temperatures and salinities, tend to increase the number of larval instars and of morphological forms. The frequency of moulting is controlled mainly by temperature. Regression equations describing the relations between the durations of larval instars and temperature are given for both Crangon species. The number of moults is a linear function of larval age and a power function of temperature. There is high variation in growth (measured as carapace length), moulting frequency, morphogenesis, and survival among hatches originating from different females. The interrelations between these different measures of larval development in shrimps and prawns are discussed.

  5. Batch fertility and larval parameters of the jaguar cichlid (Cichlasoma managuense spawned in the laboratory (ESP

    Directory of Open Access Journals (Sweden)

    Jorge Günther Nonell

    2016-03-01

    Full Text Available Batch fertility and larval parameters of 32 spawns of the jaguar guapote (Cichlasoma managuense in the laboratory were analyzed. Batch fertility was positively correlated with the female weight with spawns between about 3000 to 6000 larvae for females between 100 and 500 g wet weight. No significant correlation was found between larval parameters (fresh weight and % dry weight and female weight.

  6. Toxicity of organophosphorus pesticide sumithion on larval stages of stinging catfish Heteropneustes fossilis

    NARCIS (Netherlands)

    Shahjahan, M.; Kabir, M.F.; Sumon, Kizar Ahmed; Bhowmik, Lipi Rani; Rashid, Harunur

    2017-01-01

    Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations (150 and 250

  7. Effects of arginine vasotocin and mesotocin on the activation and development of amiloride-blockable short-circuit current across larval, adult, and cultured larval bullfrog skins.

    Science.gov (United States)

    Takada, Makoto; Fujimaki-Aoba, Kayo; Hokari, Shigeru

    2010-03-01

    Amphibian skin has osmoregulatory functions, with Na(+) crossing from outside to inside. Na(+) transport can be measured as the short-circuit current (SCC). We investigated the short-term and long-term effects of arginine vasotocin (AVT) and mesotocin (MT) (which modulate Na(+) transport) on the activation and development of an amiloride-blockable SCC (adult-type feature) in larval, adult, and corticoid-cultured larval bullfrog skins. We found: (1) AVT-receptor (AVT-R) and MT-receptor (MT-R) mRNAs could be detected in both larval and adult skins, (2) in the short term (within 60 min), the larval SCC (amiloride-stimulated SCC) was increased by AVT, forskolin, and MT, suggesting that AVT and MT did not activate the inactive ENaC (epithelial sodium channel) protein thought to be expressed in larval skin, (3) in the short term (within 90 min), AVT, forskolin, and MT stimulated the adult SCC (amiloride-blockable SCC), (4) AVT and MT increased both the larval and adult SCC via receptors insensitive to OPC-21268 (an antagonist of the V(1)-type receptor), OPC-31260 (an antagonist of the V(2)-type receptor), and ([d(CH(2))(5),Tyr(Me)(2),Thr(4),Orn(8),des-Gly-NH (2) (9) ]VT) (an antagonist of the oxytocin receptor), (5) culturing EDTA-treated larval skin with corticoids supplemented with AVT (1 microM) or MT (1 microM) for 2 weeks (long-term effects of AVT and MT) did not alter the corticoid-induced development of an amiloride-blockable SCC (adult-type feature). AVT and MT thus have the potential to stimulate SCC though channels that are already expressed, but they may not influence the development of the amiloride-blockable SCC (an adult-type feature) in larval skin.

  8. A Study of the Pelagic Larval Duration of Acropora humilis, Coral Recruitment and Connectivity in the Saudi Arabian Red Sea

    KAUST Repository

    Khalil, Maha

    2011-01-01

    Combined knowledge of the pelagic larval duration of coral species and coral recruitment patterns can provide evidence of inter-reef connectivity and indicate a reef’s ability to recover. We attempted to determine the maximum pelagic larval duration

  9. Foraging behaviour and prey size spectra of larval herring Clupea harengus

    DEFF Research Database (Denmark)

    Munk, Peter

    1992-01-01

    size groups of larval herring Clupea harengus L. were studied when preying on 6 size groups of copepods. Larval swimming and attack behaviour changed with prey size and were related to the ratio between prey length and larval length. The effective search rate showed a maximum when prey length was about......, that the available biomass of food as a proportion of the predator biomass will not increase. In order to assess the uniformity of relative prey size spectra of herring larvae and their background in larval foraging behaviour, a set of experimental and field investigations has been carried out. In the experiments, 4...... in the biomass spectra of the environment is important to larval growth and survival....

  10. Descriptions of four larval forms of Nilodosis Kieffer from East Asia

    Directory of Open Access Journals (Sweden)

    Hongqu Tang

    2012-10-01

    Full Text Available Larval material putatively assigned to the genus Nilodosis Kieffer from Korea, China and Japan has been compared. The results show that the Japanese larval form has the club- to balloon-shaped cephalic setae S7 and S9 in common with the Korean larval form, but it can be separated from the latter by the shape of the inner mandibular teeth and the premandibular teeth. The larval forms from China (Guangdong and Yunnan apparently consist of two independent species. It is most likely that there will be more species in this genus found in Asia. Larvae are mud-sandy bottom-dwellers that can occur in the littoral of lakes and the potamal of larger rivers, up to a maximum depth of 5 meters. The specific larval characters show that it probably is a semi-psammorheophilic predator. doi: 10.5324/fn.v31i0.1406.Published online: 17 October 2012. 

  11. Determination of the efficiency of diets for larval development in mass rearing Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Gunathilaka, P A D H N; Uduwawala, U M H U; Udayanga, N W B A L; Ranathunge, R M T B; Amarasinghe, L D; Abeyewickreme, W

    2017-11-23

    Larval diet quality and rearing conditions have a direct and irreversible effect on adult traits. Therefore, the current study was carried out to optimize the larval diet for mass rearing of Aedes aegypti, for Sterile Insect Technique (SIT)-based applications in Sri Lanka. Five batches of 750 first instar larvae (L 1) of Ae. aegypti were exposed to five different concentrations (2-10%) of International Atomic Energy Agency (IAEA) recommended the larval diet. Morphological development parameters of larva, pupa, and adult were detected at 24 h intervals along with selected growth parameters. Each experiment was replicated five times. General Linear Modeling along with Pearson's correlation analysis were used for statistical treatments. Significant differences (P rate and success, sex ratio, adult success, fecundity and hatching rate of Ae. aegypti. The best quality adults can be produced at larval diet concentration of 10%. However, the 8% larval diet concentration was most suitable for adult male survival.

  12. A Marriage Of Larval Modeling And Empirical Data: Linking Adult, Larval And Juvenile Scallops In An Estuary

    Science.gov (United States)

    Bayer, S.; Wahle, R.; Brooks, D. A.; Brady, D. C.

    2016-02-01

    The giant sea scallop, Placopecten magellanicus, is a commercially valuable sedentary broadcast spawner that occupies offshore banks and coastal bays and estuaries in the Northwest Atlantic. Although area closures have helped repopulate depleted scallop populations, little is known about whether populations at densities that yield larvae supply local or distant populations. Surveying scallop populations in the Damariscotta River estuary in Maine during the 2013 and 2014 spawning seasons, and settling out spat bags to collect settling larvae along the gradient of the estuary, we were able to compare adult densities to newly settled juvenile (`spat') abundance. Using the location where we found a high density of adults, we incorporated previously published behavior, pelagic larval duration, wind and current data into a particle dispersal model within the estuary to determine likely sinks for larvae from the 2013 and 2014 spawning seasons. Preliminary model simulations demonstrate where in the estuary swimming is effective in affecting water column position for larvae, and that most larvae are retained much closer to the mouth of the estuary than previously expected. Combining larval dispersal modeling with empirical data on adult densities and spat settlement on the scale of an embayment or estuary may be helpful in determining sources, sinks and areas that are both sources and sinks for shellfish species that are endangered or economically critical. This may aid in determining small area closures or Marine Protected Areas along coastal regions in the Gulf of Maine and beyond.

  13. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Directory of Open Access Journals (Sweden)

    Paula Pappalardo

    Full Text Available Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule, which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in

  14. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Science.gov (United States)

    Pappalardo, Paula; Rodríguez-Serrano, Enrique; Fernández, Miriam

    2014-01-01

    Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule), which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding) development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in muricids gastropods.

  15. Regional and seasonal differences in growth of larval North Sea herring (clupea harengus L.) estimated by otolith microstructure analysis

    DEFF Research Database (Denmark)

    Munk, Peter; Heath, Mike; Skaarup, Bo

    1991-01-01

    The ecology processes of the larval life of autumn-spawned North Sea herring have been studied in a multidisciplinary and internationally coordinated research programme (ACE). The programme focused on larval advection and the importance of the autumn/winter circulation in determining larval distr...

  16. 29 CFR 780.615 - Raising of livestock.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Raising of livestock. 780.615 Section 780.615 Labor... Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption Requirements for Exemption § 780.615 Raising of livestock. Livestock auction operations are within the 13(b)(13) exemption only...

  17. Taxonomic review of the chironomid genus Cricotopus v.d. Wulp (Diptera: Chironomidae) from Australia: keys to males, females, pupae and larvae, description of ten new species and comments on Paratrichocladius Santos Abreu.

    Science.gov (United States)

    Drayson, Nick; Cranston, Peter S; Krosch, Matt N

    2015-02-16

    The Australian species of the Orthocladiinae genus Cricotopus Wulp (Diptera: Chironomidae) are revised for larval, pupal, adult male and female life stages. Eleven species, ten of which are new, are recognised and keyed, namely Cricotopus acornis Drayson & Cranston sp. nov., Cricotopus albitarsis Hergstrom sp. nov., Cricotopus annuliventris (Skuse), Cricotopus brevicornis Drayson & Cranston sp. nov., Cricotopus conicornis Drayson & Cranston sp. nov., Cricotopus hillmani Drayson & Cranston, sp. nov., Cricotopus howensis Cranston sp. nov., Cricotopus parbicinctus Hergstrom sp. nov., Cricotopus tasmania Drayson & Cranston sp. nov., Cricotopus varicornis Drayson & Cranston sp. nov. and Cricotopus wangi Cranston & Krosch sp. nov. Using data from this study, we consider the wider utility of morphological and molecular diagnostic tools in untangling species diversity in the Chironomidae. Morphological support for distinguishing Cricotopus from Paratrichocladius Santo-Abreu in larval and pupal stages appears lacking for Australian taxa and brief notes are provided concerning this matter.

  18. Modelling larval transport in a axial convergence front

    Science.gov (United States)

    Robins, P.

    2010-12-01

    Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

  19. Surrogate mothers: aboriginal grandmothers raising grandchildren in Taiwan.

    Science.gov (United States)

    Chang, Yu-Ting; Hayter, Mark

    2011-05-01

    The purpose of this qualitative study was to understand the experiences of Taiwanese aboriginal grandmothers when raising their grandchildren. Adopting a phenomenological approach, interviews were conducted with 15 Taiwanese aboriginal grandmothers who served as primary caregiver to a grandchild or grandchildren. Data were analyzed using Giorgi's phenomenological method. Four themes emerged from the data analysis, reflecting the parenting experience of grandmothers: using aged bodies to do energetic work: represented the physical effects of raising grandchildren; conflicting emotions: reflected the psychological effects of raising grandchildren; lifelong and privative obligation: described the cultural and societal beliefs of raising grandchildren; and coping strategies for raising grandchildren outlined methods the grandmothers used to cope with parenting their grandchildren. The results of this study offers insights into surrogate parenting within an underresearched group in Taiwan and will enable health care providers to be more aware of the physical, emotional, and social effects of the role of grandparent parenting.

  20. Effects of Field-Relevant Concentrations of Clothianidin on Larval Development of the Butterfly Polyommatus icarus (Lepidoptera, Lycaenidae).

    Science.gov (United States)

    Basley, Kate; Goulson, Dave

    2018-04-03

    Arable field margins are often sown with wildflowers to encourage pollinators and other beneficial or desirable insects such as bees and butterflies. Concern has been raised that these margins may be contaminated with systemic pesticides such as neonicotinoids used on the adjacent crop, and that this may negatively impact beneficial insects. The use of neonicotinoids has been linked to butterfly declines, and species such as the common blue butterfly ( Polyommatus icarus) that feed upon legumes commonly sown in arable field margins, may be exposed to such toxins. Here, we demonstrate that the larval food plants of P. icarus growing in an arable field margin adjacent to a wheat crop treated with the neonicotinoid clothianidin not only contain the pesticide at concentrations comparable to and sometimes higher than those found in foliage of treated crops (range 0.2-48 ppb) but also remain detectable at these levels for up to 21 months after sowing of the crop. Overall, our study demonstrates that nontarget herbivorous organisms in arable field margins are likely to be chronically exposed to neonicotinoids. Under laboratory conditions, exposure to clothianidin at 15 ppb (a field-realistic dose) or above reduced larval growth for the first 9 days of the experiment. Although there was evidence of clothianidin inducing mortality in larvae, with highest survival in control groups, the dose-response relationship was unclear. Our study suggests that larvae of this butterfly exhibit some deleterious sublethal and sometimes lethal impacts of exposure to clothianidin, but many larvae survive to adulthood even when exposed to high doses.

  1. The role of dopamine in Drosophila larval classical olfactory conditioning.

    Directory of Open Access Journals (Sweden)

    Mareike Selcho

    Full Text Available Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt as well as appetitive (odor-sugar associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive

  2. Strategic larval decision-making in a bivoltine butterfly.

    Science.gov (United States)

    Friberg, Magne; Dahlerus, Josefin; Wiklund, Christer

    2012-07-01

    In temperate areas, insect larvae must decide between entering winter diapause or developing directly and reproducing in the same season. Long daylength and high temperature promote direct development, which is generally associated with a higher growth rate. In this work, we investigated whether the larval pathway decision precedes the adjustment of growth rate (state-independent), or whether the pathway decision is conditional on the individual's growth rate (state-dependent), in the butterfly Pieris napi. This species typically makes the pathway decision in the penultimate instar. We measured growth rate throughout larval development under two daylengths: slightly shorter and slightly longer than the critical daylength. Results indicate that the pathway decision can be both state-independent and state-dependent; under the shorter daylength condition, most larvae entered diapause, and direct development was chosen exclusively by a small subset of larvae showing the highest growth rates already in the early instars; under the longer daylength condition, most larvae developed directly, and the diapause pathway was chosen exclusively by a small subset of slow-growing individuals. Among the remainder, the choice of pathway was independent of the early growth rate; larvae entering diapause under the short daylength grew as fast as or faster than the direct developers under the longer daylength in the early instars, whereas the direct developers grew faster than the diapausers only in the ultimate instar. Hence, the pathway decision was state-dependent in a subset with a very high or very low growth rate, whereas the decision was state-independent in the majority of the larvae, which made the growth rate adjustment downstream from the pathway decision.

  3. Embryonic and larval development of Brycon amazonicus (SPIX & AGASSIZ, 1829

    Directory of Open Access Journals (Sweden)

    A. C. S. Sampaio Nakauth

    Full Text Available Abstract The objective of this study was to describe the embryonic and larval development of Brycon amazonicus, featuring the main events up to 50 hours after fertilization (AF. The material was provided by the Aquaculture Training, Technology and Production Center, Presidente Figueiredo (AM. The characterization was based on stereomicroscopic examination of the morphology of eggs, embryos and larvae and comparison with the literature. Matrinxã eggs are free, transparent, and spherical, with a perivitelline space of 0.56 ± 0.3 mm. The successive divisions give rise to cells with 64 blastomeres during the first hour AF. The gastrula stage, beginning 02 h 40 min AF, was characterized by progressive regression cells and the formation of the embryonic axis, leading to differentiation of the head and tail 05 h 30 min AF. From 06 to 09 h AF the somites, notochord, otic and optic vesicles and otoliths were observed, in addition to heart rate and the release of the tail. The larvae hatched at 10 h 30 min AF (29.9 °C, with a total length of 3.56 ± 0.46 mm. Between 19 and 30 h AF, we observed 1 pigmentation and gut formation, 2 branchial arches, 3 pectoral fins, 4 a mouth opening and 5 teeth. Cannibalism was initiated earlier (34 h AF which was associated with rapid yolk absorption (more than 90% until 50 h AF, signaling the need for an exogenous nutritional source. The environmental conditions (especially temperature influenced the time course of some events throughout the embryonic and larval development, suggesting the need for further studies on this subject.

  4. Proteomics insights: proteins related to larval attachment and metamorphosis of marine invertebrates

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2014-10-31

    The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTMs) are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  5. Proteomics Insights: Proteins related to Larval Attachment and Metamorphosis of Marine Invertebrates

    Directory of Open Access Journals (Sweden)

    KONDETHIMMANAHALLI eCHANDRAMOULI

    2014-10-01

    Full Text Available The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTM are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  6. Proteomics insights: proteins related to larval attachment and metamorphosis of marine invertebrates

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Qian, Pei-Yuan; Ravasi, Timothy

    2014-01-01

    The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTMs) are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  7. Larval settlement and metamorphosis of the mussel Mytilus coruscus in response to monospecific bacterial biofilms.

    Science.gov (United States)

    Yang, Jin-Long; Shen, Pei-Jing; Liang, Xiao; Li, Yi-Feng; Bao, Wei-Yang; Li, Jia-Le

    2013-01-01

    The effects of bacterial biofilms (BFs) on larval settlement and metamorphosis of the mussel, Mytilus coruscus, were investigated in the laboratory. Of nine different isolates, Shewanella sp.1 BF induced the highest percentage of larval settlement and metamorphosis, whereas seven other isolates had a moderate inducing activity and one isolate, Pseudoalteromonas sp. 4, had a no inducing activity. The inducing activity of individual bacterial isolates was not correlated either with their phylogenetic relationship or with the surfaces from which they were isolated. Among the eight bacterial species that demonstrated inducing activity, bacterial density was significantly correlated with the inducing activity for each strain, with the exception of Vibrio sp. 1. The Shewanella sp. 1 BF cue that was responsible for inducing larval settlement and metamorphosis was further investigated. Treatment of the BFs with formalin, antibiotics, ultraviolet irradiation, heat, and ethanol resulted in a significant decrease in their inducing activities and cell survival. BF-conditioned water (CW) did not induce larval metamorphosis, but it triggered larval settlement behavior. A synergistic effect of CW with formalin-fixed Shewanella sp. 1 BF significantly promoted larval metamorphosis. Thus, a cocktail of chemical cues derived from bacteria may be necessary to stimulate larval settlement and metamorphosis in this species.

  8. [Design and application of medical electric leg-raising machine].

    Science.gov (United States)

    Liang, Jintang; Chen, Jinyuan; Zhao, Zixian; Lin, Jinfeng; Li, Juanhong; Zhong, Jingliang

    2017-08-01

    Passive leg raising is widely used in clinic, but it lacks of specialized mechanical raise equipment. It requires medical staff to raise leg by hand or requires a multi-functional bed to raise leg, which takes time and effort. Therefore we have developed a new medical electric leg-raising machine. The equipment has the following characteristics: simple structure, stable performance, easy operation, fast and effective, safe and comfortable. The height range of the lifter is 50-120 cm, the range of the angle of raising leg is 10degree angle-80degree angle, the maximum supporting weight is 40 kg. Because of raising the height of the lower limbs and making precise angle, this equipment can completely replace the traditional manner of lifting leg by hand with multi-functional bed to lift patients' leg and can reduce the physical exhaustion and time consumption of medical staff. It can change the settings at any time to meet the needs of the patient; can be applied to the testing of PLR and dynamically assessing the hemodynamics; can prevent deep vein thrombosis and some related complications of staying in bed; and the machine is easy to be cleaned and disinfected, which can effectively avoid hospital acquired infection and cross infection; and can also be applied to emergency rescue of various disasters and emergencies.

  9. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan; Wang, Hao; Matsumura, Kiyotaka; Qian, Pei-Yuan

    2012-01-01

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  10. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2012-02-13

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  11. Contributions of Anopheles larval control to malaria suppression in tropical Africa: review of achievements and potential.

    Science.gov (United States)

    Walker, K; Lynch, M

    2007-03-01

    Malaria vector control targeting the larval stages of mosquitoes was applied successfully against many species of Anopheles (Diptera: Culicidae) in malarious countries until the mid-20th Century. Since the introduction of DDT in the 1940s and the associated development of indoor residual spraying (IRS), which usually has a more powerful impact than larval control on vectorial capacity, the focus of malaria prevention programmes has shifted to the control of adult vectors. In the Afrotropical Region, where malaria is transmitted mainly by Anopheles funestus Giles and members of the Anopheles gambiae Giles complex, gaps in information on larval ecology and the ability of An. gambiae sensu lato to exploit a wide variety of larval habitats have discouraged efforts to develop and implement larval control strategies. Opportunities to complement adulticiding with other components of integrated vector management, along with concerns about insecticide resistance, environmental impacts, rising costs of IRS and logistical constraints, have stimulated renewed interest in larval control of malaria vectors. Techniques include environmental management, involving the temporary or permanent removal of anopheline larval habitats, as well as larviciding with chemical or biological agents. This present review covers large-scale trials of anopheline larval control methods, focusing on field studies in Africa conducted within the past 15 years. Although such studies are limited in number and scope, their results suggest that targeting larvae, particularly in human-made habitats, can significantly reduce malaria transmission in appropriate settings. These approaches are especially suitable for urban areas, where larval habitats are limited, particularly when applied in conjunction with IRS and other adulticidal measures, such as the use of insecticide treated bednets.

  12. Investigation and management of a raised serum ferritin.

    Science.gov (United States)

    Cullis, Jonathan O; Fitzsimons, Edward J; Griffiths, William Jh; Tsochatzis, Emmanouil; Thomas, D Wayne

    2018-05-01

    Serum ferritin level is one of the most commonly requested investigations in both primary and secondary care. Whilst low serum ferritin levels invariably indicate reduced iron stores, raised serum ferritin levels can be due to multiple different aetiologies, including iron overload, inflammation, liver or renal disease, malignancy, and the recently described metabolic syndrome. A key test in the further investigation of an unexpected raised serum ferritin is the serum transferrin saturation. This guideline reviews the investigation and management of a raised serum ferritin level. The investigation and management of genetic haemochromatosis is not dealt with however and is the subject of a separate guideline. © 2018 John Wiley & Sons Ltd.

  13. Does white clover (Trifolium repens abundance in temperate pastures determine Sitona obsoletus (Coleoptera: Curculionidae larval populations?

    Directory of Open Access Journals (Sweden)

    Mark Richard McNeill

    2016-09-01

    Full Text Available To determine if host plant abundance determined the size of clover root weevil (CRW Sitona obsoletus larval populations, a study was conducted over four years in plots sown in ryegrass (Lolium perenne (cv. Nui sown at either 6 or 30 kg/ha and white clover (Trifolium repens sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand with % clover measured in autumn (April and spring (September of each year. Overall, mean larval densities measured in spring 2012, 2013, 2014 and 2015 were 310, 38, 59 and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3 and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October larval populations to % white clover measured in each plot in autumn (April found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted

  14. Does White Clover (Trifolium repens) Abundance in Temperate Pastures Determine Sitona obsoletus (Coleoptera: Curculionidae) Larval Populations?

    Science.gov (United States)

    McNeill, Mark R; van Koten, Chikako; Cave, Vanessa M; Chapman, David; Hodgson, Hamish

    2016-01-01

    To determine if host plant abundance determined the size of clover root weevil (CRW) Sitona obsoletus larval populations, a study was conducted over 4 years in plots sown in ryegrass ( Lolium perenne ) (cv. Nui) sown at either 6 or 30 kg/ha and white clover ( Trifolium repens ) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012-2015 were 310, 38, 59, and 31 larvae m -2 , respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted, but the numbers

  15. Blood Pressure Medications: Can They Raise My Triglycerides?

    Science.gov (United States)

    ... medications: Can they raise my triglycerides? Can some blood pressure medications cause an increase in triglycerides? Answers from Sheldon G. Sheps, M.D. Yes, some blood pressure medications can affect triglyceride and cholesterol levels. Hydrochlorothiazide ...

  16. Rapid Acquisition Imaging Spectrograph (RAISE) Renewal Proposal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The optical design of RAISE is based on a new class of UV/EUV imaging spectrometers that use  only two reflections to provide quasi-stigmatic performance...

  17. Federal Tax Issues Raised by International Study Abroad Programs.

    Science.gov (United States)

    Harding, Bertrand M., Jr.

    2000-01-01

    Identifies and describes tax issues raised by study abroad programs and suggests steps that a college or university can take to minimize or eliminate adverse U.S. and foreign tax exposure to both itself and its employees. (EV)

  18. HAPPINESS ORIENTATIONS AMONG ADOLESCENTS RAISED IN URBAN AND RURAL AREAS

    Directory of Open Access Journals (Sweden)

    Anisti Anggraeny

    2016-08-01

    Full Text Available Researcher takes particular interest to discover the respondents’ orientation towards happiness based on where the respondent was raised. The study involves 467 senior high school students with ages ranging from 14-17 years old. The data is analyzed using an adapted society psychological approach. The results shows that adolescents raised in rural areas are consider the family to be a factor that contributes to their happiness. Second, achievement is also a factor that leads to happiness. However for the category, to love and be loved, adolescents growing in urban areas place this as a factor that leads to happiness. Similar with spirituality, friends and leisure time are factors that make adolescents raised in urban areas to become happy. Nevertheless, the results of cross tabulation with Pearson chi square test scoring demonstrates that no correlations exist between adolescent happiness raised from urban or rural areas.

  19. Evaluation of the use of snowplowable raised pavement markers.

    Science.gov (United States)

    2009-04-01

    The objective of this study was to evaluate the effectiveness and durability of snowplowable raised pavement markers (RPM) installed on the RPM system in Kentucky. The durability evaluation dealt wit the marker housing. : The data show that continued...

  20. Pregnancy Choices: Raising the Baby, Adoption, and Abortion

    Science.gov (United States)

    ... PREGNANCY Pregnancy Choices: Raising the Baby, Adoption, and Abortion • What are my options if I find out ... is financial help available? • If I am considering abortion, what should I know about my state’s laws? • ...

  1. Government grant control of development of stock-raising

    OpenAIRE

    SAMOYLIK YU.V.

    2012-01-01

    Directions of improvement of mechanism of government grant control of development of stock-raising are offered on the basis of the educed tendencies and conformities to law in the existent system of sponsorship of industry.

  2. Capital raising of aerospace companies: equities or debts?

    Science.gov (United States)

    Hui-Shan, L.; Taw-Onn, Y.; Wai-Mun, H.

    2016-10-01

    Aerospace products enhance national and economic activities, thus maintaining the sustainability of aerospace industry is crucial. One of the perspectives in ensuring sustainability of aerospace companies is expansion of firms by raising funds for research and development in order to provide a reasonable profitability to the firms. This study comprises a sample of 47 aerospace companies from 2009 to 2015 to analyze the impact of raising fund by equities or debts to the profitability of the firms. The result indicates that capital raising through equities is preferable than debts. Moreover, the study also identifies that the profit of aerospace industry is volatile and there is cyclical reduction of the net income in the first quarter of the year. The management needs to make wise decisions in raising fund to ensure a healthy growth of the aerospace company.

  3. Supersensitive gastrin assay using antibodies raised against a cholecystokinin homolog

    DEFF Research Database (Denmark)

    Rehfeld, Jens F; Ericsson, Peter

    2012-01-01

    Peptide hormones may occur in particularly low amounts in samples from small animals. Hence, in a rat microdialysis study conventional immunoassays were not sufficiently sensitive to measure gastrin in the dialysis samples. We therefore exploited the observation that antibodies raised against...... that obtained with the most avid conventional gastrin antibodies. The results may encourage similar approaches for other peptides using homologue-raised antibodies when supersensitivity is required....

  4. Raised Plasma Aldosterone and Natriuretic Peptides in Atrial Fibrillation

    DEFF Research Database (Denmark)

    Dixen, Ulrik; Ravn, Lasse Steen; Soeby-Rasmussen, Christian

    2006-01-01

    at follow-up, total duration of AF disease, ongoing medication, and the LVEF as explanatory variables showed that only ongoing treatment with diuretics was significantly associated (likelihood ratio test, p = 0.0057) with a raised log-transformed plasma aldosterone, although present AF at follow......-transformed plasma Nt-proANP. Likewise, present AF at follow-up (p = 0.0008) as well as age (p raised levels of Nt-proANP and Nt...

  5. THE EXCEPTION OF UNCONSTITUTIONALITY RAISED BEFORE AN INTERNATIONAL ARBITRAL TRIBUNAL

    OpenAIRE

    Eugen HURUBÃ; Luminita GABURA

    2014-01-01

    The main aim of the paper work is to determine whether the Constitutional Court of Romania could be notified by international tribunals in relation to cases tried under Romanian law. On 5 March 2013 the Constitutional Court of Romania decided, for the first time, on a case concerning an exception of unconstitutionality raised before an international tribunal of commercial arbitration. The exception of unconstitutionality of a Government Emergency Ordinance was raised in an arbitration case pe...

  6. Trans-life cycle acclimation to experimental ocean acidification affects gastric pH homeostasis and larval recruitment in the sea star Asterias rubens.

    Science.gov (United States)

    Hu, Marian Y; Lein, Etienne; Bleich, Markus; Melzner, Frank; Stumpp, Meike

    2018-04-16

    Experimental simulation of near-future ocean acidification (OA) has been demonstrated to affect growth and development of echinoderm larval stages through energy allocation towards ion and pH compensatory processes. To date, it remains largely unknown how major pH regulatory systems and their energetics are affected by trans-generational exposure to near-future acidification levels. Here we used the common sea star Asterias rubens in a reciprocal transplant experiment comprising different combinations of OA scenarios, in order to study trans-generational plasticity using morphological and physiological endpoints. Acclimation of adults to pH T 7.2 (pCO 2 3500μatm) led to reductions in feeding rates, gonad weight, and fecundity. No effects were evident at moderate acidification levels (pH T 7.4; pCO 2 2000μatm). Parental pre-acclimation to pH T 7.2 for 85 days reduced developmental rates even when larvae were raised under moderate and high pH conditions, whereas pre-acclimation to pH T 7.4 did not alter offspring performance. Microelectrode measurements and pharmacological inhibitor studies carried out on larval stages demonstrated that maintenance of alkaline gastric pH represents a substantial energy sink under acidified conditions that may contribute up to 30% to the total energy budget. Parental pre-acclimation to acidification levels that are beyond the pH that is encountered by this population in its natural habitat (e.g. pH T 7.2) negatively affected larval size and development, potentially through reduced energy transfer. Maintenance of alkaline gastric pH and reductions in maternal energy reserves probably constitute the main factors for a reduced juvenile recruitment of this marine keystone species under simulated OA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Differential patterns of accumulation and retention of dietary trace elements associated with coal ash during larval development and metamorphosis of an amphibian.

    Science.gov (United States)

    Heyes, Andrew; Rowe, Christopher L; Conrad, Phillip

    2014-01-01

    We performed an experiment in which larval gray tree frogs (Hyla chrysoscelis) were raised through metamorphosis on diets increased with a suite of elements associated with coal combustion residues (silver [Ag], arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], mercury [Hg], lead [Pb], selenium [Se], vanadium [V], and zinc [Zn]) at "low" and "high" concentrations. We quantified accumulation of metals at three life stages (mid-larval development, initiation of metamorphosis, and completion of metamorphosis) as well as effects on survival, metabolic rate, size at metamorphosis, and duration and loss of weight during metamorphosis. Most elements were accumulated in a dose-dependent pattern by some or all life stages, although this was not the case for Hg. For most elements, larval body burdens exceeded those of later life stages in some or all treatments (control, low, or high). However for Se, As, and Hg, body burdens in control and low concentrations were increased in later compared with earlier life stages. A lack of dose-dependent accumulation of Hg suggests that the presence of high concentrations of other elements (possibly Se) either inhibited accumulation or increased depuration of Hg. The duration of metamorphosis (forelimb emergence through tail resorption) was lengthened in individuals exposed to the highest concentrations of elements, but there were no other statistically significant biological effects. This study shows that patterns of accumulation and possibly depuration of metals and trace elements are complex in animals possessing complex life cycles. Further study is required to determine specific interactions affecting these patterns, in particular which elements may be responsible for affecting accumulation or retention of Hg when organisms are exposed to complex mixtures of elements.

  8. Density-dependent growth and metamorphosis in the larval bronze ...

    Indian Academy of Sciences (India)

    Effects of density and kinship on growth and metamorphosis in tadpoles of Rana temporalis were studied in a 2 × 4 factorial experiment. Fifteen egg masses were collected from streams in the Western Ghat region of south India. The tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz ...

  9. Observations on the reproductive and larval biology of Blennius pavo (Pisces: Teleostei)

    Science.gov (United States)

    Westernhagen, H.

    1983-09-01

    Social behaviour and spawning of adult Blennius pavo kept in the laboratory are described. Eggs are deposited in batches on the walls of artificial spawning places (PVC pipes). One male guards and tends the eggs of different females in one spawning place. Larval hatching occurs in groups according to oviposition. Minimum incubation temperature is around 14 15°C. Larval survival in 1-1 rearing jars is not related to larval total length but to density of larval stock. An experimental population of laboratory reared juvenile and adolescent B. pavo displays a male to female ratio of 1:1.4. Factors possibly influencing the sex ratio of this littoral fish are discussed in view of the situation in its natural environment.

  10. Diel and Lunar Variations in Larval Fish Supply in Malindi Marine ...

    African Journals Online (AJOL)

    2Department of Fisheries and Aquatic Sciences, University of Eldoret, PO Box 1125, Eldoret, Kenya; ... in fish larval occurrence was thus studied in Malindi Marine Park, Kenya, to assess diel and lunar ..... New South Wales University Press,.

  11. Quantitative proteomics identify molecular targets that are crucial in larval settlement and metamorphosis of bugula neritina

    KAUST Repository

    Zhang, Huoming; Wong, Yuehim; Wang, Hao; Chen, Zhangfan; Arellano, Shawn M.; Ravasi, Timothy; Qian, Peiyuan

    2011-01-01

    The marine invertebrate Bugula neritina has a biphasic life cycle that consists of a swimming larval stage and a sessile juvenile and adult stage. The attachment of larvae to the substratum and their subsequent metamorphosis have crucial ecological

  12. Circatrigintan instead of lunar periodicity of larval release in a brooding coral species.

    Science.gov (United States)

    Linden, Bart; Huisman, Jef; Rinkevich, Baruch

    2018-04-04

    Larval release by brooding corals is often assumed to display lunar periodicity. Here, we show that larval release of individual Stylophora pistillata colonies does not comply with the assumed tight entrainment by the lunar cycle, and can better be classified as a circatrigintan pattern. The colonies exhibited three distinct reproductive patterns, characterized by short intervals, long intervals and no periodicity between reproductive peaks, respectively. Cross correlation between the lunar cycle and larval release of the periodic colonies revealed an approximately 30-day periodicity with a variable lag of 5 to 10 days after full moon. The observed variability indicates that the lunar cycle does not provide a strict zeitgeber. Other factors such as water temperature and solar radiation did not correlate significantly with the larval release. The circatrigintan patterns displayed by S. pistillata supports the plasticity of corals and sheds new light on discussions on the fecundity of brooding coral species.

  13. AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

  14. When similar beginnings lead to different ends: Constraints and diversity i cirripede larval development

    DEFF Research Database (Denmark)

    Høeg, Jens Thorvald; Møller, Ole Sten

    2006-01-01

    Cirripedes are fascinating models for studying both functional constraints and diversity in larval development. Adult cirripedes display an amazing variation in morphology from sessile suspension feeders that still retain many crustacean characters to parasites that have lost virtually all...

  15. Strengthened currents override the effect of warming on lobster larval dispersal and survival

    NARCIS (Netherlands)

    Cetina-Heredia, Paulina; Roughan, Moninya; van Sebille, Erik; Feng, Ming; Coleman, Melinda A.

    2015-01-01

    Human-induced climate change is projected to increase ocean temperature and modify circulation patterns, with potential widespread implications for the transport and survival of planktonic larvae of marine organisms. Circulation affects the dispersal of larvae, whereas temperature impacts larval

  16. Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

    Science.gov (United States)

    Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

  17. Seasonal variability in penaeid prawn larval abundance in the Mandovi and Zuari estuaries, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Goswami, U.

    more in the bottom samples. Based on larval density, M. dobsoni appeared to be a continuous breeder. The active spawning periods in other species were during the late postmonsoon and premonsoon seasons varying with the species. Peak recruitment...

  18. Relevance of biofilm bacteria in modulating the larval metamorphosis of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Raghukumar, S.

    Balanus amphitrite, on its larval metamorphosis. The effect of multispecies bacterial film was also assessed. The production of different molecules by the bacteria was influenced by the nutrient media under which they were grown. It was observed...

  19. Stock-specific advection of larval walleye (Sander vitreus) in western Lake Erie: Implications for larval growth, mixing, and stock discrimination

    Science.gov (United States)

    Fraker, Michael E.; Anderson, Eric J.; May, Cassandra J.; Chen, Kuan-Yu; Davis, Jeremiah J.; DeVanna, Kristen M.; DuFour, Mark R.; Marschall, Elizabeth A.; Mayer, Christine M.; Miner, Jeffery G.; Pangle, Kevin L.; Pritt, Jeremy J.; Roseman, Edward F.; Tyson, Jeffrey T.; Zhao, Yingming; Ludsin, Stuart A

    2015-01-01

    Physical processes can generate spatiotemporal heterogeneity in habitat quality for fish and also influence the overlap of pre-recruit individuals (e.g., larvae) with high-quality habitat through hydrodynamic advection. In turn, individuals from different stocks that are produced in different spawning locations or at different times may experience dissimilar habitat conditions, which can underlie within- and among-stock variability in larval growth and survival. While such physically-mediated variation has been shown to be important in driving intra- and inter-annual patterns in recruitment in marine ecosystems, its role in governing larval advection, growth, survival, and recruitment has received less attention in large lake ecosystems such as the Laurentian Great Lakes. Herein, we used a hydrodynamic model linked to a larval walleye (Sander vitreus) individual-based model to explore how the timing and location of larval walleye emergence from several spawning sites in western Lake Erie (Maumee, Sandusky, and Detroit rivers; Ohio reef complex) can influence advection pathways and mixing among these local spawning populations (stocks), and how spatiotemporal variation in thermal habitat can influence stock-specific larval growth. While basin-wide advection patterns were fairly similar during 2011 and 2012, smaller scale advection patterns and the degree of stock mixing varied both within and between years. Additionally, differences in larval growth were evident among stocks and among cohorts within stocks which were attributed to spatiotemporal differences in water temperature. Using these findings, we discuss the value of linked physical–biological models for understanding the recruitment process and addressing fisheries management problems in the world's Great Lakes.

  20. Role of serotonergic neurons in the Drosophila larval response to light

    Directory of Open Access Journals (Sweden)

    Campos Ana

    2009-06-01

    Full Text Available Abstract Background Drosophila larval locomotion consists of forward peristalsis interrupted by episodes of pausing, turning and exploratory behavior (head swinging. This behavior can be regulated by visual input as seen by light-induced increase in pausing, head swinging and direction change as well as reduction of linear speed that characterizes the larval photophobic response. During 3rd instar stage, Drosophila larvae gradually cease to be repelled by light and are photoneutral by the time they wander in search for a place to undergo metamorphosis. Thus, Drosophila larval photobehavior can be used to study control of locomotion. Results We used targeted neuronal silencing to assess the role of candidate neurons in the regulation of larval photobehavior. Inactivation of DOPA decarboxylase (Ddc neurons increases the response to light throughout larval development, including during the later stages of the 3rd instar characterized by photoneutral response. Increased response to light is characterized by increase in light-induced direction change and associated pause, and reduction of linear movement. Amongst Ddc neurons, suppression of the activity of corazonergic and serotonergic but not dopaminergic neurons increases the photophobic response observed during 3rd instar stage. Silencing of serotonergic neurons does not disrupt larval locomotion or the response to mechanical stimuli. Reduced serotonin (5-hydroxytryptamine, 5-HT signaling within serotonergic neurons recapitulates the results obtained with targeted neuronal silencing. Ablation of serotonergic cells in the ventral nerve cord (VNC does not affect the larval response to light. Similarly, disruption of serotonergic projections that contact the photoreceptor termini in the brain hemispheres does not impact the larval response to light. Finally, pan-neural over-expression of 5-HT1ADro receptors, but not of any other 5-HT receptor subtype, causes a significant decrease in the response to

  1. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan

    2011-07-29

    Background: The barnacle Balanus amphitrite is a globally distributed biofouler and a model species in intertidal ecology and larval settlement studies. However, a lack of genomic information has hindered the comprehensive elucidation of the molecular mechanisms coordinating its larval settlement. The pyrosequencing-based transcriptomic approach is thought to be useful to identify key molecular changes during larval settlement. Methodology and Principal Findings: Using 454 pyrosequencing, we collected totally 630,845 reads including 215,308 from the larval stages and 415,537 from the adults; 23,451 contigs were generated while 77,785 remained as singletons. We annotated 31,720 of the 92,322 predicted open reading frames, which matched hits in the NCBI NR database, and identified 7,954 putative genes that were differentially expressed between the larval and adult stages. Of these, several genes were further characterized with quantitative real-time PCR and in situ hybridization, revealing some key findings: 1) vitellogenin was uniquely expressed in late nauplius stage, suggesting it may be an energy source for the subsequent non-feeding cyprid stage; 2) the locations of mannose receptors suggested they may be involved in the sensory system of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval settlement. Conclusions: Our results provide not only the basis of several new hypotheses about gene functions during larval settlement, but also the availability of this large transcriptome dataset in B. amphitrite for further exploration of larval settlement and developmental pathways in this important marine species. © 2011 Chen et al.

  2. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    Takken Willem

    2010-01-01

    Full Text Available Abstract Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density, fungus (species and concentration and environmental effects (exposure duration and food availability influence larval mortality caused by fungus, was studied. Methods Laboratory bioassays were performed on the larval stages of Anopheles gambiae and Anopheles stephensi with spores of two fungus species, Metarhizium anisopliae and Beauveria bassiana. For various larval and fungal characteristics and environmental effects the time to death was determined and survival curves established. These curves were compared by Kaplan Meier and Cox regression analyses. Results Beauveria bassiana and Metarhizium anisopliae caused high mortality of An. gambiae and An. stephensi larvae. However, Beauveria bassiana was less effective (Hazard ratio (HR Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR Conclusions This study shows that both fungus species have potential to kill mosquitoes in the larval stage, and that mortality rate depends on fungus species itself, larval stage targeted, larval density and amount of nutrients available to the larvae. Increasing the concentration of fungal spores or reducing the exposure time to spores did not show a proportional increase and decrease in mortality rate, respectively, because the spores clumped together. As a result spores did not provide uniform coverage over space and time. It is, therefore, necessary to develop a formulation that allows the spores to spread over the water surface. Apart from formulation appropriate delivery methods are also necessary to avoid exposing non-target organisms to fungus.

  3. Larval nematodes in stomach wall granulomas of smelt Osmerus eperlanus from the German North Sea coast

    OpenAIRE

    Obiekezie, A. I.; Lick, Roland R.; Kerstan, Susanne L.; Möller, Heino

    1992-01-01

    Occurrence of stomach wall granulomas in European smelt was studled at 6 locations along the German North Sea coast. Identification of larval nematodes inhabiting these granulomas is provided for the first time. Three species, isolated by pepsin-HC1 digestion, are involved: Hysterothylacium cf. cornutum, Cosmocephalus obvelatus and Paracuaria tridentata. 72% of all stomachs examined were affected. The ratio of number of granulomas to number of the 3 larval species free in the mesentery was 1:...

  4. Larval developmental rate, metabolic rate and future growth performance in Atlantic salmon

    DEFF Research Database (Denmark)

    Serrano, Jonathan Vaz; Åberg, Madelene; Gjoen, Hans Magnus

    2009-01-01

    , quantified as time to first feeding, and growth in later stages was demonstrated in Atlantic salmon (Salmo salar L.). The observed relationship between future growth and larval developmental rate suggests that sorting larvae by time to first feeding can be a potential tool to optimize feeding strategies...... and growth in commercial rearing of Atlantic salmon. Furthermore, the link between larval standard metabolic rate and developmental rate and future growth is discussed in the present study....

  5. Effects of temperature on embryonic and larval development and growth in the natterjack toad (Bufo calamita in a semi-arid zone

    Directory of Open Access Journals (Sweden)

    Sanuy, D.

    2008-06-01

    Full Text Available Temperature affects the duration of embryonic and larval periods in amphibians. Plasticity in time to metamorphosis is especially important in amphibian populations of Mediterranean semi-arid zones where temperatures are high and precipitation is low, increasing the rate of pond desiccation. In order to test the influence of water temperature on the larval development and growth of the natterjack toad (Bufo calamita, we collected two spawns in a semi¿arid zone at Balaguer (Lleida, NE Iberian peninsula. Approximately 50 (+/-10 eggs (stage 14-16 were raised in the lab at different temperature conditions: 10, 15, 20, 22.5 and 25ºC with 12:12 photoperiod. The results show a lengthening of development time with decreasing temperatures and a better survival performance of B. calamita to high temperatures. However, mean size at metamorphosis was not different across treatments, thus, suggesting that this population of B. calamita requires a minimum size to complete the metamorphosis. This study is the first approach to examine the effects that climatic factors have on the growth and development of B. calamita in semi-arid zones.

  6. Larval connectivity of pearl oyster through biophysical modelling; evidence of food limitation and broodstock effect

    Science.gov (United States)

    Thomas, Yoann; Dumas, Franck; Andréfouët, Serge

    2016-12-01

    The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia atoll lagoons. This aquaculture relies on spat collection, a process that experiences spatial and temporal variability and needs to be optimized by understanding which factors influence recruitment. Here, we investigate the sensitivity of P. margaritifera larval dispersal to both physical and biological factors in the lagoon of Ahe atoll. Coupling a validated 3D larval dispersal model, a bioenergetics larval growth model following the Dynamic Energy Budget (DEB) theory, and a population dynamics model, the variability of lagoon-scale connectivity patterns and recruitment potential is investigated. The relative contribution of reared and wild broodstock to the lagoon-scale recruitment potential is also investigated. Sensitivity analyses pointed out the major effect of the broodstock population structure as well as the sensitivity to larval mortality rate and inter-individual growth variability to larval supply and to the subsequent settlement potential. The application of the growth model clarifies how trophic conditions determine the larval supply and connectivity patterns. These results provide new cues to understand the dynamics of bottom-dwelling populations in atoll lagoons, their recruitment, and discuss how to take advantage of these findings and numerical models for pearl oyster management.

  7. Bioenergetics models to estimate numbers of larval lampreys consumed by smallmouth bass in Elk Creek, Oregon

    Science.gov (United States)

    Schultz, Luke; Heck, Michael; Kowalski, Brandon M; Eagles-Smith, Collin A.; Coates, Kelly C.; Dunham, Jason B.

    2017-01-01

    Nonnative fishes have been increasingly implicated in the decline of native fishes in the Pacific Northwest. Smallmouth Bass Micropterus dolomieu were introduced into the Umpqua River in southwest Oregon in the early 1960s. The spread of Smallmouth Bass throughout the basin coincided with a decline in counts of upstream-migrating Pacific Lampreys Entosphenus tridentatus. This suggested the potential for ecological interactions between Smallmouth Bass and Pacific Lampreys, as well as freshwater-resident Western Brook Lampreys Lampetra richardsoni. To evaluate the potential effects of Smallmouth Bass on lampreys, we sampled diets of Smallmouth Bass and used bioenergetics models to estimate consumption of larval lampreys in a segment of Elk Creek, a tributary to the lower Umpqua River. We captured 303 unique Smallmouth Bass (mean: 197 mm and 136 g) via angling in July and September. We combined information on Smallmouth Bass diet and energy density with other variables (temperature, body size, growth, prey energy density) in a bioenergetics model to estimate consumption of larval lampreys. Larval lampreys were found in 6.2% of diet samples, and model estimates indicated that the Smallmouth Bass we captured consumed 925 larval lampreys in this 2-month study period. When extrapolated to a population estimate of Smallmouth Bass in this segment, we estimated 1,911 larval lampreys were consumed between July and September. Although the precision of these estimates was low, this magnitude of consumption suggests that Smallmouth Bass may negatively affect larval lamprey populations.

  8. How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

    Science.gov (United States)

    Beachy, Christopher K.; Ryan, Travis J.; Bonett, Ronald M.

    2017-01-01

    Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids. PMID:29269959

  9. Species associations among larval helminths in an amphipod intermediate host.

    Science.gov (United States)

    Dezfuli, B S; Giari, L; Poulin, R

    2000-10-01

    Larval helminths that share the same intermediate host may or may not also share the same definitive hosts. If one or more of these helminth species can manipulate the phenotype of the intermediate host, there can be great advantages or severe costs for other helminths resulting from co-occurring with a manipulator, depending on whether they have the same definitive host or not. Among 2372 specimens of the amphipod Echinogammarus stammeri collected from the river Brenta, northern Italy, there was a positive association between two acanthocephalan species with the same fish definitive hosts, the relatively common Pomphorhynchus laevis and the much less prevalent Acanthocephalus clavula. The number of cystacanths of P. laevis per infected amphipod, which ranged from one to five, did not influence the likelihood that the amphipod would also host A. clavula. A third acanthocephalan species, Polymorphus minutus,which matures in birds, showed no association with either of the two other species. These results show that associations among helminth species in intermediate hosts are not random, and are instead the product of selection favouring certain pathways of transmission.

  10. Two hemocyte lineages exist in silkworm larval hematopoietic organ.

    Directory of Open Access Journals (Sweden)

    Yuichi Nakahara

    Full Text Available BACKGROUND: Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. METHODOLOGY/PRINCIPAL FINDINGS: To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. CONCLUSIONS/SIGNIFICANCE: From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

  11. Two hemocyte lineages exist in silkworm larval hematopoietic organ.

    Science.gov (United States)

    Nakahara, Yuichi; Kanamori, Yasushi; Kiuchi, Makoto; Kamimura, Manabu

    2010-07-28

    Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO) into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

  12. Demersal and larval fish assemblages in the Chukchi Sea

    Science.gov (United States)

    Norcross, Brenda L.; Holladay, Brenda A.; Busby, Morgan S.; Mier, Kathryn L.

    2010-01-01

    A multidisciplinary research cruise was conducted in the Chukchi Sea in summer 2004 during which we investigated assemblages of small demersal fishes and ichthyoplankton and the water masses associated with these assemblages. This study establishes a baseline of 30 demersal fish and 25 ichthyoplankton taxa in US and Russian waters of the Chukchi Sea. Presence/absence of small demersal fish clustered into four assemblages: Coastal Fishes, Western Chukchi Fishes, South Central Chukchi Fishes, and North Central Chukchi Fishes. Habitats occupied by small demersal fishes were characterized by sediment type, bottom salinity, and bottom temperature. Abundance of ichthyoplankton grouped into three assemblages with geographical extent similar to that of the bottom assemblages, except that there was a single assemblage for Central Chukchi Fishes. Water-column temperature and salinity characterized ichthyoplankton habitats. Three water masses, Alaska Coastal Water, Bering Sea Water, and Winter Water, were identified from both bottom and depth-averaged water-column temperature and salinity. A fourth water mass, Resident Chukchi Water, was identified only in the bottom water. The water mass and habitat characteristics with which demersal and larval fish assemblages were associated create a baseline to measure anticipated effects of climate change that are expected to be most severe at high latitudes. Monitoring fish assemblages could be a tool for assessing the effects of climate change. Climate-induced changes in distributions of species would result in a restructuring of fish assemblages in the Chukchi Sea.

  13. Growth and mortality of larval Myctophum affine (Myctophidae, Teleostei).

    Science.gov (United States)

    Namiki, C; Katsuragawa, M; Zani-Teixeira, M L

    2015-04-01

    The growth and mortality rates of Myctophum affine larvae were analysed based on samples collected during the austral summer and winter of 2002 from south-eastern Brazilian waters. The larvae ranged in size from 2·75 to 14·00 mm standard length (L(S)). Daily increment counts from 82 sagittal otoliths showed that the age of M. affine ranged from 2 to 28 days. Three models were applied to estimate the growth rate: linear regression, exponential model and Laird-Gompertz model. The exponential model best fitted the data, and L(0) values from exponential and Laird-Gompertz models were close to the smallest larva reported in the literature (c. 2·5 mm L(S)). The average growth rate (0·33 mm day(-1)) was intermediate among lanternfishes. The mortality rate (12%) during the larval period was below average compared with other marine fish species but similar to some epipelagic fishes that occur in the area. © 2015 The Fisheries Society of the British Isles.

  14. Preference for and learning of amino acids in larval Drosophila

    Directory of Open Access Journals (Sweden)

    Nana Kudow

    2017-03-01

    Full Text Available Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.

  15. Interactive effects of maternal and environmental exposure to coal combustion wastes decrease survival of larval southern toads (Bufo terrestris)

    International Nuclear Information System (INIS)

    Metts, Brian S.; Buhlmann, Kurt A.; Scott, David E.; Tuberville, Tracey D.; Hopkins, William A.

    2012-01-01

    We conducted a mesocosm study to assess the individual and interactive effects of previous maternal exposure and larval exposure to trace element-laden sediments on southern toads (Bufo terrestris). Previous maternal exposure to coal combustion wastes (CCW) reduced larval survival to metamorphosis up to 57% compared to larvae of unexposed females. Larvae reared on CCW accumulated significant concentrations of trace elements resulting in extended larval periods, reduced growth rates, and reduced mass at metamorphosis. However, the effects were dependent on age of sediments, suggesting the effects of contaminants from CCW may be partially ameliorated over time through the reduced bioavailability of trace elements in aged CCW. Most importantly, maternal exposure to contaminants coupled with larval exposure to fresh CCW interacted to reduce survival to metamorphosis by 85% compared to reference conditions. Our study yields further evidence that disposal of CCW in aquatic basins potentially creates ecological traps for some amphibian populations. - Highlights: ► The interaction of maternal exposure and larval exposure to CCW reduced survival. ► Previous maternal exposure to CCW had a latent effect on survival to metamorphosis. ► Larval southern toads exposed to CCW experienced prolonged larval periods. ► Larval southern toads exposed to CCW had reduced growth rates. ► Larval southern toads exposed to CCW had reduced mass at metamorphosis. - Maternal and environmental exposure to coal combustion wastes interact to decrease survival in larval amphibians.

  16. Larval traits carry over to affect post-settlement behaviour in a common coral reef fish.

    Science.gov (United States)

    Dingeldein, Andrea L; White, J Wilson

    2016-07-01

    Most reef fishes begin life as planktonic larvae before settling to the reef, metamorphosing and entering the benthic adult population. Different selective forces determine survival in the planktonic and benthic life stages, but traits established in the larval stage may carry over to affect post-settlement performance. We tested the hypothesis that larval traits affect two key post-settlement fish behaviours: social group-joining and foraging. Certain larval traits of reef fishes are permanently recorded in the rings in their otoliths. In the bluehead wrasse (Thalassoma bifasciatum), prior work has shown that key larval traits recorded in otoliths (growth rate, energetic condition at settlement) carry over to affect post-settlement survival on the reef, with higher-larval-condition fish experiencing less post-settlement mortality. We hypothesized that this selective mortality is mediated by carry-over effects on post-settlement antipredator behaviours. We predicted that better-condition fish would forage less and be more likely to join groups, both behaviours that would reduce predation risk. We collected 550 recently settled bluehead wrasse (Thalassoma bifasciatum) from three reef sites off St. Croix (USVI) and performed two analyses. First, we compared each settler's larval traits to the size of its social group to determine whether larval traits influenced group-joining behaviour. Secondly, we observed foraging behaviour in a subset of grouped and solitary fish (n = 14) for 1-4 days post-settlement. We then collected the fish and tested whether larval traits influenced the proportion of time spent foraging. Body length at settlement, but not condition, affected group-joining behaviour; smaller fish were more likely to remain solitary or in smaller groups. However, both greater length and better condition were associated with greater proportions of time spent foraging over four consecutive days post-settlement. Larval traits carry over to affect post

  17. Is the Schwabe Organ a Retained Larval Eye? Anatomical and Behavioural Studies of a Novel Sense Organ in Adult Leptochiton asellus (Mollusca, Polyplacophora Indicate Links to Larval Photoreceptors.

    Directory of Open Access Journals (Sweden)

    Lauren H Sumner-Rooney

    Full Text Available The discovery of a sensory organ, the Schwabe organ, was recently reported as a unifying feature of chitons in the order Lepidopleurida. It is a patch of pigmented tissue located on the roof of the pallial cavity, beneath the velum on either side of the mouth. The epithelium is densely innervated and contains two types of potential sensory cells. As the function of the Schwabe organ remains unknown, we have taken a cross-disciplinary approach, using anatomical, histological and behavioural techniques to understand it. In general, the pigmentation that characterises this sensory structure gradually fades after death; however, one particular concentrated pigment dot persists. This dot is positionally homologous to the larval eye in chiton trochophores, found in the same neuroanatomical location, and furthermore the metamorphic migration of the larval eye is ventral in species known to possess Schwabe organs. Here we report the presence of a discrete subsurface epithelial structure in the region of the Schwabe organ in Leptochiton asellus that histologically resembles the chiton larval eye. Behavioural experiments demonstrate that Leptochiton asellus with intact Schwabe organs actively avoid an upwelling light source, while Leptochiton asellus with surgically ablated Schwabe organs and a control species lacking the organ (members of the other extant order, Chitonida do not (Kruskal-Wallis, H = 24.82, df = 3, p < 0.0001. We propose that the Schwabe organ represents the adult expression of the chiton larval eye, being retained and elaborated in adult lepidopleurans.

  18. The urodelean Mauthner cell. Morphology of the afferent synapses to the M-cell of larval Salamandra salamandra

    Energy Technology Data Exchange (ETDEWEB)

    Cioni, C; De Palma, F; De Vito, L; Stefanelli, A [Rome, Univ. (Italy). Dipt. di Biologia Animale e dell` Uomo

    1998-12-31

    In the present work the fine morphology and the distribution of the afferent synapses to the Mauthner cell of larval Salamandra salamandra are described. The aim of the study is to characterize the synaptic bed in the larvae of this terrestrial salamander in order to compare it with that of larval axolotl and larval anurans. Four main types of afferent endings have been identified: myelinated club endings, round-vesicle end bulbs, flattened-vesicle end bulbs and spiral fibers endings. The M-cell afferent synaptology of larval stages of terrestrial amphibians is quite similar to that previously observed in larval stages of aquatic species. This fact can be related to the fundamental similarities between the larval lifestyles.

  19. The urodelean Mauthner cell. Morphology of the afferent synapses to the M-cell of larval Salamandra salamandra

    Energy Technology Data Exchange (ETDEWEB)

    Cioni, C.; De Palma, F.; De Vito, L.; Stefanelli, A. [Rome, Univ. (Italy). Dipt. di Biologia Animale e dell`Uomo

    1997-12-31

    In the present work the fine morphology and the distribution of the afferent synapses to the Mauthner cell of larval Salamandra salamandra are described. The aim of the study is to characterize the synaptic bed in the larvae of this terrestrial salamander in order to compare it with that of larval axolotl and larval anurans. Four main types of afferent endings have been identified: myelinated club endings, round-vesicle end bulbs, flattened-vesicle end bulbs and spiral fibers endings. The M-cell afferent synaptology of larval stages of terrestrial amphibians is quite similar to that previously observed in larval stages of aquatic species. This fact can be related to the fundamental similarities between the larval lifestyles.

  20. Biocontrol of larval mosquitoes by Acilius sulcatus (Coleoptera: Dytiscidae

    Directory of Open Access Journals (Sweden)

    Banerjee Siddhartha S

    2008-10-01

    Full Text Available Abstract Background Problems associated with resistant mosquitoes and the effects on non-target species by chemicals, evoke a reason to find alternative methods to control mosquitoes, like the use of natural predators. In this regard, aquatic coleopterans have been explored less compared to other insect predators. In the present study, an evaluation of the role of the larvae of Acilius sulcatus Linnaeus 1758 (Coleoptera: Dytiscidae as predator of mosquito immatures was made in the laboratory. Its efficacy under field condition was also determined to emphasize its potential as bio-control agent of mosquitoes. Methods In the laboratory, the predation potential of the larvae of A. sulcatus was assessed using the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae as prey at varying predator and prey densities and available space. Under field conditions, the effectiveness of the larvae of A. sulcatus was evaluated through augmentative release in ten cemented tanks hosting immatures of different mosquito species at varying density. The dip density changes in the mosquito immatures were used as indicator for the effectiveness of A. sulcatus larvae. Results A single larva of A. sulcatus consumed on an average 34 IV instar larvae of Cx. quinquefasciatus in a 24 h period. It was observed that feeding rate of A. sulcatus did not differ between the light-on (6 a.m. – 6 p.m., and dark (6 p.m. – 6 a.m. phases, but decreased with the volume of water i.e., space availability. The prey consumption of the larvae of A. sulcatus differed significantly (P A. sulcatus larvae, while with the withdrawal, a significant increase (p A. sulcatus in regulating mosquito immatures. In the control tanks, mean larval density did not differ (p > 0.05 throughout the study period. Conclusion the larvae of the dytiscid beetle A. sulcatus proved to be an efficient predator of mosquito immatures and may be useful in biocontrol of medically important mosquitoes.

  1. Muscle organizers in Drosophila: the role of persistent larval fibers in adult flight muscle development

    Science.gov (United States)

    Farrell, E. R.; Fernandes, J.; Keshishian, H.

    1996-01-01

    In many organisms muscle formation depends on specialized cells that prefigure the pattern of the musculature and serve as templates for myoblast organization and fusion. These include muscle pioneers in insects and muscle organizing cells in leech. In Drosophila, muscle founder cells have been proposed to play a similar role in organizing larval muscle development during embryogenesis. During metamorphosis in Drosophila, following histolysis of most of the larval musculature, there is a second round of myogenesis that gives rise to the adult muscles. It is not known whether muscle founder cells organize the development of these muscles. However, in the thorax specific larval muscle fibers do not histolyze at the onset of metamorphosis, but instead serve as templates for the formation of a subset of adult muscles, the dorsal longitudinal flight muscles (DLMs). Because these persistent larval muscle fibers appear to be functioning in many respects like muscle founder cells, we investigated whether they were necessary for DLM development by using a microbeam laser to ablate them singly and in combination. We found that, in the absence of the larval muscle fibers, DLMs nonetheless develop. Our results show that the persistent larval muscle fibers are not required to initiate myoblast fusion, to determine DLM identity, to locate the DLMs in the thorax, or to specify the total DLM fiber volume. However, they are required to regulate the number of DLM fibers generated. Thus, while the persistent larval muscle fibers are not obligatory for DLM fiber formation and differentiation, they are necessary to ensure the development of the correct number of fibers.

  2. Effect of corticosterone on larval growth, antipredator behaviour and metamorphosis of Hylarana indica.

    Science.gov (United States)

    Kulkarni, P S; Gramapurohit, N P

    2017-09-15

    Corticosterone (CORT), a principal glucocorticoid in amphibians, is known to regulate diverse physiological processes including growth and metamorphosis of anuran tadpoles. Environmental stressors activate the neuroendocrine stress axis (hypothalamus-pituitary-interrenal axis, HPI) leading to an acute increase in CORT, which in turn, helps in coping with particular stress. However, chronic increase in CORT can negatively affect other physiological processes such as growth and metamorphosis. Herein, we studied the effect of exogenous CORT on larval growth, antipredator behaviour and metamorphic traits of Hylarana indica. Embryonic exposure to 5 or 20μg/L CORT did not affect their development, hatching duration as well as larval growth and metamorphosis. Exposure of tadpoles to 10 or 20μg/L CORT throughout larval development caused slower growth and development leading to increased body mass at stage 37. However, body and tail morphology of tadpoles was not affected. Interestingly, larval exposure to 5, 10 or 20μg/L CORT enhanced their antipredator response against kairomones in a concentration-dependent manner. Further, larval exposure to increasing concentrations of CORT resulted in the emergence of heavier froglets at 10 and 20μg/L while, delaying metamorphosis at all concentrations. Interestingly, the heavier froglets had shorter hindlimbs and consequently shorter jump distances. Tadpoles exposed to 20μg/L CORT during early, mid or late larval stages grew and developed slowly but tadpole morphology was not altered. Interestingly, exposure during early or mid-larval stages resulted in an enhanced antipredator response. These individuals metamorphosed later but at higher body mass while SVL was unaffected. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. The hidden magnitude of raised blood pressure and elevated blood ...

    African Journals Online (AJOL)

    Conclusions: The prevalence of undiagnosed raised blood pressure and elevated blood sugar was high in Ethiopia and only very small percentage of people had been aware of their high blood pressure and elevated blood sugar. Policy makers in the health sector including other health development partners need to ...

  4. Options for meeting the ecological Reserve for a raised Clanwilliam ...

    African Journals Online (AJOL)

    A recent evaluation of the potential raising of Clanwilliam Dam included an assessment of whether the operation of the dam would meet the flow quality and quantity requirements for the protection of the downstream river and its estuary, taking Olifants/Doring River basin-level considerations into account. The implications of ...

  5. With Dwindling Resources, Colleges Recalibrate Fund-Raising Staffs

    Science.gov (United States)

    Masterson, Kathryn

    2009-01-01

    After several years of aggressive hiring, some college fund-raising operations are now cutting back as both revenue and investment income fall. The regrouping could slow growth plans on many campuses at a time when the need for private support has never been greater. Often the colleges cutting employees are laying off back-office staff members and…

  6. VOWEL RAISING IN AKAN REDUPLICATION Kwesi Adomako1 ...

    African Journals Online (AJOL)

    In this current paper, we provide an alternative analysis to this overgeneralized claim by providing data from the Twi (Asante) dialect to argue for the presence and productivity of the raising of both the low and the mid vowels within diverse phonological contexts. In these contexts, the stem/base-final low vowel /a/ in the CVa.

  7. Consciousness-raising about grammar in the second-language ...

    African Journals Online (AJOL)

    Consciousness-raising about grammar in the second-language classroom: Utilising authentic samples of learner-learner interaction in a task-based oral activity. ... More recent studies argue that linguistic support must not be omitted from language teaching programmes within a task-based, communicative approach (Swain, ...

  8. 47 CFR 25.282 - Orbit raising maneuvers.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Orbit raising maneuvers. 25.282 Section 25.282 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... geostationary satellite orbit under this part is also authorized to transmit in connection with short-term...

  9. Raising Cultural Awareness in the English Language Classroom

    Science.gov (United States)

    Frank, Jerrold

    2013-01-01

    This article discusses how teachers can incorporate cultural knowledge into English language classes, exploring elements of culture, intercultural phenomena, and high-context and low-context cultures. Activities offered by the author to raise cultural awareness include web quests, role plays, cultural observations, and culture journals.

  10. Babbitt's Brothers & Sisters: Raising Ethical Issues in Business Literature.

    Science.gov (United States)

    Halpern, Jeanne W.

    A college-level course in business literature is an ideal place to raise and discuss ethical issues. To be successful, a teacher of this course must engage student interest, help the students articulate and understand their own ethical attitudes, clarify the stance and artistry of the author, and refine student responses to ethical questions. When…

  11. Operating Classroom Aesthetic Reading Environment to Raise Children's Reading Motivation

    Science.gov (United States)

    Chou, Mei-Ju; Cheng, Jui-Ching; Cheng, Ya-Wen

    2016-01-01

    This research aims to explore how preschool educators understand about raising children's reading motivation through operating classroom aesthetic reading environment. With one year qualitative research, sixteen 4-6 years old young were observed and interviewed. The first stage interviews were undergone with environmental guidance. After the…

  12. Raising Quality and Achievement. A College Guide to Benchmarking.

    Science.gov (United States)

    Owen, Jane

    This booklet introduces the principles and practices of benchmarking as a way of raising quality and achievement at further education colleges in Britain. Section 1 defines the concept of benchmarking. Section 2 explains what benchmarking is not and the steps that should be taken before benchmarking is initiated. The following aspects and…

  13. Social partners divided over government plan to raise retirement age

    NARCIS (Netherlands)

    Grünell, M.

    2009-01-01

    The social partners have given a divided response to the Dutch cabinet’s plans to raise the retirement age - first to 66 years in 2020 and then to 67 years in 2025. This also applies to the age at which company pension schemes will be paid out. The trade unions argue that poorly paid workers who

  14. Performance of dairy calves raised under two breeding systems

    Directory of Open Access Journals (Sweden)

    Reinaldo Henrique Borger

    2017-05-01

    Full Text Available Increasing concern about some animal production systems has placed considerable value on humanitarian breeding systems, aimed at ensuring animal welfare and comfort. Raising calves is one of the most important stages in a milk production system. This study aimed to evaluate and compare the performance of Holstein dairy calves raised by two farming systems: conventional individual (CI and collective with automatic calf feeder (CACF. Fourteen, 15-day-old Holstein dairy calves having an average initial body weight of 40 kg, were used. The animals were distributed in a completely randomized design with seven animals per treatment. The variables evaluated were the milk and feed intake, body weight, hip height, thoracic circumference and daily weight gain. The average milk intake was lower in the CACF (3.5 L animal-1 day-1 than CI (5.1 L animal-1 day-1 system. However, the feed intake was higher in the CACF (1.205 kg animal-1 day-1 compared to CI (0.910 kg animal-1 day-1 system. Body weight, thoracic circumference, hip height and daily weight gain were similar between the two systems. The CACF raised calves had a higher concentrate intake and lower milk intake than the calves raised under the CI system.

  15. Raising Emotionally Intelligent Teenagers: Parenting with Love, Laughter, and Limits.

    Science.gov (United States)

    Elias, Maurice J.; Tobias, Steven E.; Friedlander, Brian S.

    Based on the formula of love, laughter, limits, and linkages, this book presents practical, parent-tested ways parents can help their adolescent children become emotionally intelligent. The book is presented in three parts. Part 1 concerns parent preparation for raising an emotionally intelligent teenager, discusses the importance of parenting by…

  16. Redesigning Schools to Raise Achievement. Item Number 39-0464

    Science.gov (United States)

    American Federation of Teachers, 2003

    2003-01-01

    The primary goal of the American Federation of Teachers' (AFT) Redesigning Schools to Raise Achievement (RSRA) project is to build capacity at the state, district, school, and classroom levels to improve student achievement to meet the goals of the 2001 No Child Left Behind Act. This checklist highlights some of the opportunities and support…

  17. Metaphorical Perceptions of the Concepts "Teaching Profession" and "Raising Students"

    Science.gov (United States)

    Bezen, Sevim; Aykutlu, Isil; Secken, Nilgun; Bayrak, Celai

    2017-01-01

    Purpose of Study: This study aims to reveal, via metaphors, pre-service biology teachers' perceptions of "teaching profession" and "raising students." Research Methods: In accordance with the aim of the study, phenomenology, one of the qualitative paradigm patterns, is used. The study group consists of 80 pre-service biology…

  18. Eggshells as an index of aedine mosquito production. 2: Relationship of Aedes taeniorhynchus eggshell density to larval production.

    Science.gov (United States)

    Addison, D S; Ritchie, S A; Webber, L A; Van Essen, F

    1992-03-01

    To test if eggshell density could be used as an index of aedine mosquito production, we compared eggshell density with the larval production of Aedes taeniorhynchus in Florida mangrove basin forests. Quantitative (n = 7) and categorical (n = 34) estimates of annual larval production were regressed against the number of eggshells per cc of soil. Significant regressions were obtained in both instances. Larval production was concentrated in zones with the highest eggshell density. We suggest that eggshell density and distribution can be used to identify oviposition sites and the sequence of larval appearance.

  19. Embryogenesis and larval biology of the cold-water coral Lophelia pertusa.

    Directory of Open Access Journals (Sweden)

    Ann I Larsson

    Full Text Available Cold-water coral reefs form spectacular and highly diverse ecosystems in the deep sea but little is known about reproduction, and virtually nothing about the larval biology in these corals. This study is based on data from two locations of the North East Atlantic and documents the first observations of embryogenesis and larval development in Lophelia pertusa, the most common framework-building cold-water scleractinian. Embryos developed in a more or less organized radial cleavage pattern from ∼ 160 µm large neutral or negatively buoyant eggs, to 120-270 µm long ciliated planulae. Embryogenesis was slow with cleavage occurring at intervals of 6-8 hours up to the 64-cell stage. Genetically characterized larvae were sexually derived, with maternal and paternal alleles present. Larvae were active swimmers (0.5 mm s(-1 initially residing in the upper part of the water column, with bottom probing behavior starting 3-5 weeks after fertilization. Nematocysts had developed by day 30, coinciding with peak bottom-probing behavior, and possibly an indication that larvae are fully competent to settle at this time. Planulae survived for eight weeks under laboratory conditions, and preliminary results indicate that these planulae are planktotrophic. The late onset of competency and larval longevity suggests a high dispersal potential. Understanding larval biology and behavior is of paramount importance for biophysical modeling of larval dispersal, which forms the basis for predictions of connectivity among populations.

  20. Larval settlement: the role of surface topography for sessile coral reef invertebrates.

    Science.gov (United States)

    Whalan, Steve; Wahab, Muhammad A Abdul; Sprungala, Susanne; Poole, Andrew J; de Nys, Rocky

    2015-01-01

    For sessile marine invertebrates with complex life cycles, habitat choice is directed by the larval phase. Defining which habitat-linked cues are implicated in sessile invertebrate larval settlement has largely concentrated on chemical cues which are thought to signal optimal habitat. There has been less effort establishing physical settlement cues, including the role of surface microtopography. This laboratory based study tested whether surface microtopography alone (without chemical cues) plays an important contributing role in the settlement of larvae of coral reef sessile invertebrates. We measured settlement to tiles, engineered with surface microtopography (holes) that closely matched the sizes (width) of larvae of a range of corals and sponges, in addition to surfaces with holes that were markedly larger than larvae. Larvae from two species of scleractinian corals (Acropora millepora and Ctenactis crassa) and three species of coral reef sponges (Luffariella variabilis, Carteriospongia foliascens and Ircinia sp.,) were used in experiments. L. variabilis, A. millepora and C. crassa showed markedly higher settlement to surface microtopography that closely matched their larval width. C. foliascens and Ircinia sp., showed no specificity to surface microtopography, settling just as often to microtopography as to flat surfaces. The findings of this study question the sole reliance on chemical based larval settlement cues, previously established for some coral and sponge species, and demonstrate that specific physical cues (surface complexity) can also play an important role in larval settlement of coral reef sessile invertebrates.

  1. Gene expression patterns during the larval development of European sea bass (dicentrarchus labrax) by microarray analysis.

    Science.gov (United States)

    Darias, M J; Zambonino-Infante, J L; Hugot, K; Cahu, C L; Mazurais, D

    2008-01-01

    During the larval period, marine teleosts undergo very fast growth and dramatic changes in morphology, metabolism, and behavior to accomplish their metamorphosis into juvenile fish. Regulation of gene expression is widely thought to be a key mechanism underlying the management of the biological processes required for harmonious development over this phase of life. To provide an overall analysis of gene expression in the whole body during sea bass larval development, we monitored the expression of 6,626 distinct genes at 10 different points in time between 7 and 43 days post-hatching (dph) by using heterologous hybridization of a rainbow trout cDNA microarray. The differentially expressed genes (n = 485) could be grouped into two categories: genes that were generally up-expressed early, between 7 and 23 dph, and genes up-expressed between 25 and 43 dph. Interestingly, among the genes regulated during the larval period, those related to organogenesis, energy pathways, biosynthesis, and digestion were over-represented compared with total set of analyzed genes. We discuss the quantitative regulation of whole-body contents of these specific transcripts with regard to the ontogenesis and maturation of essential functions that take place over larval development. Our study is the first utilization of a transcriptomic approach in sea bass and reveals dynamic changes in gene expression patterns in relation to marine finfish larval development.

  2. Predator-induced larval cloning in the sand dollar Dendraster excentricus: might mothers matter?

    Science.gov (United States)

    Vaughn, Dawn

    2009-10-01

    Predator-induced cloning in echinoid larvae, with reduced size a consequence of cloning, is a dramatic modification of development and a novel response to risks associated with prolonged planktonic development. Recent laboratory studies demonstrate that exposure to stimuli from predators (i.e., fish mucus) induces cloning in the pluteus larvae (plutei) of Dendraster excentricus. However, the timing and incidence of cloning and size reduction of unrelated conspecific plutei differed across experiments. A variable cloning response suggests the effects of such factors as cue quality, egg provisioning, maternal experience, and genetic background, indicating that the potential advantages of cloning as an adaptive response to predators are not available to all larvae. This study tested the hypothesis that cloning in D. excentricus plutei is maternally influenced. Plutei from three half-sibling larval families (different mothers, same father) were exposed to fish mucus for 9 days during early development. Cloning was inferred in a percentage of plutei from each family; however, the rate and success of cloning differed significantly among the larval half-siblings. Unexpectedly, all mucus-treated plutei were smaller and developmentally delayed when compared to all plutei reared in the absence of a mucus stimulus. Thus, while the results from this study support the hypothesis of an influence of mothers on cloning of larval offspring, reduced larval size was a uniform response to fish mucus and did not indicate an effect of mothers. Hypotheses of the developmental effects of fish mucus on larval size with or without successful cloning are discussed.

  3. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan

    2012-08-01

    The polychaete . Hydroides elegans (Serpulidae, Lophotrochozoa) is a problematic marine fouling organism in most tropical and subtropical coastal environment. Competent larvae of . H. elegans undergo the transition from the swimming larval stage to the sessile juvenile stage with substantial morphological, physiological, and behavior changes. This transition is often referred to as larval settlement and metamorphosis. In this study, we examined the possible involvement of calmodulin (CaM) - a multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid residues. It was highly expressed in 12. h post-metamorphic juveniles, and remained high in adults. . In situ hybridization conducted in competent larvae and juveniles revealed that . He-CaM gene was continuously expressed in the putative growth zones, branchial rudiments, and collar region, suggesting that . He-CaM might be involved in tissue differentiation and development. Our subsequent bioassay revealed that the CaM inhibitor W7 could effectively inhibit larval settlement and metamorphosis, and cause some morphological defects of unsettled larvae. In conclusion, our results revealed that CaM has important functions in the larval settlement and metamorphosis of . H. elegans. © 2012 Elsevier Inc..

  4. Functional genomics identifies regulators of the phototransduction machinery in the Drosophila larval eye and adult ocelli.

    Science.gov (United States)

    Mishra, Abhishek Kumar; Bargmann, Bastiaan O R; Tsachaki, Maria; Fritsch, Cornelia; Sprecher, Simon G

    2016-02-15

    Sensory perception of light is mediated by specialized Photoreceptor neurons (PRs) in the eye. During development all PRs are genetically determined to express a specific Rhodopsin (Rh) gene and genes mediating a functional phototransduction pathway. While the genetic and molecular mechanisms of PR development is well described in the adult compound eye, it remains unclear how the expression of Rhodopsins and the phototransduction cascade is regulated in other visual organs in Drosophila, such as the larval eye and adult ocelli. Using transcriptome analysis of larval PR-subtypes and ocellar PRs we identify and study new regulators required during PR differentiation or necessary for the expression of specific signaling molecules of the functional phototransduction pathway. We found that the transcription factor Krüppel (Kr) is enriched in the larval eye and controls PR differentiation by promoting Rh5 and Rh6 expression. We also identified Camta, Lola, Dve and Hazy as key genes acting during ocellar PR differentiation. Further we show that these transcriptional regulators control gene expression of the phototransduction cascade in both larval eye and adult ocelli. Our results show that PR cell type-specific transcriptome profiling is a powerful tool to identify key transcriptional regulators involved during several aspects of PR development and differentiation. Our findings greatly contribute to the understanding of how combinatorial action of key transcriptional regulators control PR development and the regulation of a functional phototransduction pathway in both larval eye and adult ocelli. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Acondicionamiento de reproductores, desove y cultivo larval de Graus nigra (Philippi, 1887 (Kyphosidae: Girellinae Broodstock conditioning, spawning and larval culture of Graus nigra (Philippi, 1887 (Kyphosidae: Girellinae

    Directory of Open Access Journals (Sweden)

    Avelino Muñoz

    2012-09-01

    Full Text Available Se describen resultados sobre acondicionamiento reproductivo, desove y cultivo larval de Graus nigra ("vieja negra", "mulata". Peces adultos silvestres se recolectaron y se utilizaron como reproductores, los que al final del período de acondicionamiento alcanzaron el estado de maduración gonadal y desovaron en forma natural y espontánea. Los huevos fueron recolectados y después de 36 h de incubación eclosionaron, con una tasa de eclosión promedio de 60%. Las larvas recién eclosionadas midieron 2,9 ± 0,23 mm y alcanzaron el día 50 post-eclosión (PE una longitud total de 12,6 ± 0,37 mm. La sobrevivencia larval posterior a la eclosión fue entre 50,9 y 79,1% y al día 30 PE fue de 12,1%. El cultivo larval se desarrolló en estanques con suministro de agua de mar filtrada y esterilizada. Después de la reabsorción del saco vitelino se produjo el desarrollo del tracto digestivo y las larvas se alimentaron con dieta viva enriquecida con emulsión de ácidos grasos altamente insaturados. A los 35 días de cultivo se ofreció alimento artificial a las larvas cuyo tamano fue aumentando progresivamente a medida que progresó su desarrollo ontogénico. Se describe la evolución anatómica de las larvas y las relaciones morfométricas que representan su desarrollo; se caracteriza el patrón de crecimiento de las larvas hasta los 50 días post-eclosión y se discuten aspectos relacionados con la sobrevivencia larval y la introducción de mejoras para optimizar la producción de larvas y juveniles.In this study results related to reproductive conditioning, spawning and larval culture of Graus nigra ("vieja negra", "mulata" are given. Wild adult fishes were collected and used as brooders which at the end of the conditioning period reached gonadal maturation state and spawned naturally and spontaneously. Eggs were collected and after 36 hours of incubation they hatched at average rate of 60%. The hatched larvae measured 2.9 ± 0.23 mm and at day 50

  6. Genetic and evolutionary analysis of the Drosophila larval neuromuscular junction

    Science.gov (United States)

    Campbell, Megan

    Although evolution of brains and behaviors is of fundamental biological importance, we lack comprehensive understanding of the general principles governing these processes or the specific mechanisms and molecules through which the evolutionary changes are effected. Because synapses are the basic structural and functional units of nervous systems, one way to address these problems is to dissect the genetic and molecular pathways responsible for morphological evolution of a defined synapse. I have undertaken such an analysis by examining morphology of the larval neuromuscular junction (NMJ) in wild caught D. melanogaster as well as in over 20 other species of Drosophila. Whereas variation in NMJ morphology within a species is limited, I discovered a surprisingly extensive variation among different species. Compared with evolution of other morphological traits, NMJ morphology appears to be evolving very rapidly. Moreover, my data indicate that natural selection rather than genetic drift is primarily responsible for evolution of NMJ morphology. To dissect underlying molecular mechanisms that may govern NMJ growth and evolutionary divergence, I focused on a naturally occurring variant in D. melanogaster that causes NMJ overgrowth. I discovered that the variant mapped to Mob2, a gene encoding a kinase adapter protein originally described in yeast as a member of the Mitotic Exit Network (MEN). I have subsequently examined mutations in the Drosophila orthologs of all the core components of the yeast MEN and found that all of them function as part of a common pathway that acts presynaptically to negatively regulate NMJ growth. As in the regulation of yeast cytokinesis, these components of the MEN appear to act ultimately by regulating actin dynamics during the process of bouton growth and division. These studies have thus led to the discovery of an entirely new role for the MEN---regulation of synaptic growth---that is separate from its function in cell division. This work

  7. Raise driving: A new drill and fire method

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, U [Bergbau A.G. Niederrhein, Oberhausen (Germany, F.R.). Werksdirektion Osterfeld; Ulrich, E [Bergbau A.G. Niederrhein, Oberhausen (Germany, F.R.). Fachbereich Planung

    1979-06-01

    Three-compartment raises have long been driven by conventional upraising. The system had inherent drawbacks, notably roof control, ventilation and dirt removal which held back any further development of the method as such. At Osterfeld colliery the single-compartment pilot shaft method has been used for the first time in the Ruhr to produce a staple shaft column. The idea behind the operation was to apply to coalmining a method which had until then been confined to ore mining and tunnelling. The experience gained during this venture is important from the point of view of further developments in raise drivage and offers facts and figures on the productivity, economics and safety aspects of the pilot shaft method.

  8. Ovarian development and early larval survival of Stenopus zanzibaricus (Bruce, 1976

    Directory of Open Access Journals (Sweden)

    Daniel Marques

    2014-06-01

    Full Text Available Despite economically valuable, ornamental shrimps are poorly studied and there is a lack of protocols for their captive breeding. Stenopus is one of the most important genera of ornamental shrimps, being Stenopus zanzibaricus one of the species with less information about captive breeding and larviculture. For a better knowledge of its reproductive cycle, we evaluated morphological and color changes during ovarian development of adult females through daily photographs taken during all the cycle. The effect of three diets (Brachionus plicatilis + Tetraselmis chuii; newly artemia nauplii + Tetraselmis chuii; newly artemia nauplii and two different temperatures (25ºC and 27ºC on early larval development were also evaluated. With this study, it was expected to obtain some insight about Stenopus zanzibaricus reproductive cycle and early larval development, in order to develop captive breeding and larval rearing protocols for this economic valuable species.

  9. A developmental and energetic basis linking larval oyster shell formation to acidification sensitivity

    Science.gov (United States)

    Waldbusser, George G.; Brunner, Elizabeth L.; Haley, Brian A.; Hales, Burke; Langdon, Christopher J.; Prahl, Frederick G.

    2013-05-01

    Acidified waters are impacting commercial oyster production in the U.S. Pacific Northwest, and favorable carbonate chemistry conditions are predicted to become less frequent. Within 48 h of fertilization, unshelled Pacific oyster (Crassostrea gigas) larvae precipitate roughly 90% of their body weight as calcium carbonate. We measured stable carbon isotopes in larval shell and tissue and in algal food and seawater dissolved inorganic carbon in a longitudinal study of larval development and growth. Using these data and measured biochemical composition of larvae, we show that sensitivity of initial shell formation to ocean acidification results from diminished ability to isolate calcifying fluid from surrounding seawater, a limited energy budget and a strong kinetic demand for calcium carbonate precipitation. Our results highlight an important link between organism physiology and mineral kinetics in larval bivalves and suggest the consideration of mineral kinetics may improve understanding winners and losers in a high CO2 world.

  10. Turbulence, larval fish ecology and fisheries recruitment : a review of field studies

    DEFF Research Database (Denmark)

    MacKenzie, Brian

    2000-01-01

    , and recruitment in entire populations. One of the main findings is that field studies show contrasting effects of turbulence on feeding, growth and mortality rates in nature and on recruitment. Coincident and multiple variations in ecosystem processes, lack of understanding of how some of these processes (e......Fish recruitment varies widely between years but much of this variability cannot be explained by most models of fish population dynamics. In this review, I examine the role of environmental variability on fish recruitment, and ill particular how turbulence affects feeding and growth of larval fish.......g. larval diet composition, feeding behaviour, growth rates, prey patchiness) respond to turbulence, and unavoidable sampling artifacts are mainly responsible for this result. Upwelling as well as frontal processes appear important for larval fish growth and survival, and turbulence levels vary both within...

  11. Diatom production in the marine environment : implications for larval fish growth and condition

    DEFF Research Database (Denmark)

    St. John, Michael; Clemmesen, C.; Lund, T.

    2001-01-01

    To test the effects of diatom production on larval fish growth and condition. laboratory experiments were performed with larval North Sea cod reared on different algal food chains. These food chains were based on cultures of (a) the diatoms Skeletonema costatum and Thalassiosira weissflogii: (b....../omega6 fatty acids in the algal source had no significant effect. The highest and lowest growth rates were observed in food chains based on H. triquetra and T. weissflogii. respectively (means for days 14-16 of 4.0 and - 4.7). The mixed diatom/dinoflagellate diet resulted in inter- mediate growth rates...... and condition. Regressions of growth rates against EPA and DHA content indicated no inhibitory effect of diatom production on growth in larval cod...

  12. Problems raised by corrosion in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Tricot, R.; Boutonnet, G.; Perrot, M.; Blum, J.-M.

    1977-01-01

    In the uranium ore processing industry, materials which resist both mechanical abrasion and corrosion in an acid medium are required. Different typical cases are examined. For the reprocessing of irradiated fuels, two processes are possible: the conventional wet process, of the Purex type, and the fluoride volatilization process. In the latter case, the problems raised by fluoride corrosion in the presence of fission products is examined. The other parts of the fuel cycle are examined in the same manner [fr

  13. Raising and Lowering Operators for Askey-Wilson Polynomials

    Directory of Open Access Journals (Sweden)

    Siddhartha Sahi

    2007-01-01

    Full Text Available In this paper we describe two pairs of raising/lowering operators for Askey-Wilson polynomials, which result from constructions involving very different techniques. The first technique is quite elementary, and depends only on the ''classical'' properties of these polynomials, viz. the q-difference equation and the three term recurrence. The second technique is less elementary, and involves the one-variable version of the double affine Hecke algebra.

  14. Aspects of the reproductive biology of hatchery-raised Clarias ...

    African Journals Online (AJOL)

    The fecundity of four batch weights (10 samples each) of gravid Clarias gariepinus weighing 60 ± 0.17159 g 125 ± 0.15092 g 250 ±0.20683 g and 500 ± 0.15670 g raised from the hatchery was investigated The paired ovary of each fish was dissected out, weighed (g) and its length measured(mm). Each paired ovary was ...

  15. Raising Growth and Investment in Sub-Saharan Africa

    OpenAIRE

    Ernesto Hernanadez-Cata

    2001-01-01

    Sub-Saharan Africa's long-term growth performance will need to improve significantly for the region to visibly reduce poverty and raise the standard of living to an acceptable level. Appropriate actions will also be needed to ensure that an adequate share of the growing income is devoted to reducing poverty. The key policy question for these countries and their development partners is how ...

  16. Raising Awareness of Conveyed Personality In Social Media Traces

    OpenAIRE

    Xu, Bin; Gou, Liang; Xu, Anbang; Mahmud, Jalal; Cosley, Dan

    2017-01-01

    Users' persistent social media contents like posts on Facebook Timeline are presented as an "exhibition" about the person to others, and managing these exhibitional contents for impression management needs intentional and manual efforts. To raise awareness of and facilitate impression management around past contents, we developed a prototype called PersonalityInsight. The system employs computational psycho-linguistic analysis to help users visualize the way their past text posts might convey...

  17. Raising students’ awareness with respect to choice of literature

    DEFF Research Database (Denmark)

    Bagger, Bettan; Taylor Kelly, Hélène; Hørdam, Britta

    is a pedagogical tool which raises students’ awareness with respect to the necessity of employing scientific and researched based material. The tool is not only used in the theoretical setting but also in clinical practice. Students and clinical advisors evaluate the relevance of the pedagogical tool via...... questionnaires. The data will be analyzed and form the basis for further innovative teaching developments promoting the theory-clinical connection in the learning environment. Keywords: literature, education, pedagogical tool, theory-practice connection....

  18. A SERIOUS GAME RAISING AWARENESS AND EXPERIENCE OF DEPRESSION

    OpenAIRE

    Plechawska-Wojcik, Malgorzata; Rybka, Joanna

    2015-01-01

    The paper presents the idea and gameplay of the serious game dedicated for both, patients suffering from depression to help them in the fight against disease and healthy individuals to raise their awareness about depression disease and increase their level of knowledge about it. Serious games are gaining more and more popularity nowadays. Using games for purpose different than only pure entertainment is the idea of serious game. On the market there are available several computer game solu...

  19. Raising consciousness about the nuclear threat through music

    Energy Technology Data Exchange (ETDEWEB)

    Ungerleider, J.H.

    1987-01-01

    This dissertation examines the use of music, in particular topical collaborative group song writing, as a tool for raising consciousness about the threat of nuclear war. Consciousness raising is one way to overcome the phenomenon of denial and to increase discussion and social action in response to the nuclear threat. This dissertation measures the impact of a group song writing workshop on developing critical problem-solving in adult groups; it reviews how music is applied in psychological research and clinical work, has been used historically as a tool in social-change movements in America, and is used in the contemporary field of peace education. The perspectives of several theorists who discuss the potential of music to contribute to social change are presented. It is concluded that consciousness about the nuclear threat - in terms of naming and analyzing - can be raised by working with music's potential for developing affective, expressive, and collaborative capabilities in individuals and groups. Potential applications of the group song writing workshop are in schools, with peace organizations, music groups, and in relation to other social issues.

  20. Cultural and Economic Motivation of Pig Raising Practices in Bangladesh.

    Science.gov (United States)

    Nahar, Nazmun; Uddin, Main; Gurley, Emily S; Jahangir Hossain, M; Sultana, Rebeca; Luby, Stephen P

    2015-12-01

    The interactions that pig raisers in Bangladesh have with their pigs could increase the risk of zoonotic disease transmission. Since raising pigs is a cultural taboo to Muslims, we aimed at understanding the motivation for raising pigs and resulting practices that could pose the risk of transmitting disease from pigs to humans in Bangladesh, a predominantly Muslim country. These understandings could help identify acceptable strategies to reduce the risk of disease transmission from pigs to people. To achieve this objective, we conducted 34 in-depth interviews among pig herders and backyard pig raisers in eight districts of Bangladesh. Informants explained that pig raising is an old tradition, embedded in cultural and religious beliefs and practices, the primary livelihood of pig herders, and a supplemental income of backyard pig raisers. To secure additional income, pig raisers sell feces, liver, bile, and other pig parts often used as traditional medicine. Pig raisers have limited economic ability to change the current practices that may put them at risk of exposure to diseases from their pigs. An intervention that improves their financial situation and reduces the risk of zoonotic disease may be of interest to pig raisers.

  1. Critics raise moral objections to Federal AIDS education classes.

    Science.gov (United States)

    1995-07-28

    Lawmakers and a handful of government employees have objected to the Federal government's programs to educate its employees about AIDS. At the June 22, 1995 hearing of the civil service subcommittee of the House Government Reform and Oversight Committee, protests were raised on religious or moral grounds. Thomas Herron, a supervisory logistics manager at the Naval Air Technical Services Facility in Philadelphia found the training to be against the principles of his faith. Rep. Robert K. Dornan (R-Calif) said his office was flooded with calls and letters from employees who raised concern that the training is being used to advance a redefinition of the family and is a blatant pro-homosexual agenda. Robert L. Maginnis, policy analyst for the conservative Family Research Council, faulted the training, saying it does little to change behavior that puts people at risk for HIV infection. Clinton administration officials testified at the meeting that the program is necessary to ensure both the safety of the workforce and employees' freedom from discrimination and harassment. Individual departments and agencies are responsible for developing their own AIDS training programs. According to Alan Heuerman, associate director for human resource systems service with the Office of Personnel Management, relatively few objections have been raised about the training.

  2. Addressing issues raised by stakeholders: experiences of eight organisations

    International Nuclear Information System (INIS)

    Vari, Anna

    2004-01-01

    Demand for stakeholder involvement has become imperative in the field of radioactive waste management. Providing for fair and competent stakeholder involvement, however, raises several questions of practice, for example: How to address issues raised by stakeholders? How to take stakeholders' views into consideration if they are divergent or conflicting? This paper reviews eight case studies prepared for the Topical Session on Addressing Issues Raised by Stakeholders, aimed at analysing the impacts of stakeholder involvement on decisions in RWM organisations. The studies outline the experiences of the following organisations: Canadian Nuclear Safety Commission (CNSC); Canadian Nuclear Waste Management Organization (NWMO); Nuclear Waste Management Organisation of Japan (NUMO); Posiva, Finland; Radioactive Waste Repository Authority, Czech Republic (RAWRA); Swedish Radiation Protection Authority (SSI); United Kingdom Environment Agency; United States Environmental Protection Agency (EPA). Case study reports are included in the Annex of this volume. The paper outlines the main trends and lessons learned from the above case studies. The first section focuses on impacts of stakeholder involvement on specific RWM decisions regarding policy and process. Examples presented in the second section illustrate how stakeholders' concerns may influence general decision-making practices and organisational behaviour. In the third section various approaches to handling divergent stakeholder views are introduced. The paper concludes with recommendations extracted and derived from the eight reports. (author)

  3. Assessing the toxicity of sediments using the medaka embryo-larval assay and 2 other bioassays.

    Science.gov (United States)

    Barhoumi, Badreddine; Clérandeau, Christelle; Landi, Laure; Pichon, Anaïk; Le Bihanic, Florane; Poirier, Dominique; Anschutz, Pierre; Budzinski, Hélène; Driss, Mohamed Ridha; Cachot, Jérôme

    2016-09-01

    Sediments are sinks for aquatic pollutants, and analyzing toxicity in such complex matrices is still challenging. To evaluate the toxicity of bioavailable pollutants accumulated in sediments from the Bizerte lagoon (Tunisia), a novel assay, the medaka embryo-larval assay by sediment contact, was applied. Japanese medaka (Oryzias latipes) embryos were incubated in direct contact with sediment samples up to hatching. Lethal and sublethal adverse effects were recorded in embryos and larvae up to 20 d postfertilization. Results from medaka embryo-larval assay were compared with cytotoxicity (Microtox®), genotoxicity (SOS chromotest), and pollutant content of sediments. The results highlight differences in the contamination profile and toxicity pattern between the different studied sediments. A significant correlation was shown between medaka embryo-larval assay by sediment contact and SOS chromotest responses and concentrations of most organic pollutants studied. No correlation was shown between pollutant levels and Microtox. According to the number of sediment samples detected as toxic, medaka embryo-larval assay by sediment contact was more sensitive than Microtox, which in turn was more sensitive than the SOS chromotest; and medaka embryo-larval assay by sediment contact allowed sediment toxicity assessment of moderately polluted sediments without pollutant extraction and using an ecologically realistic exposure scenario. Although medaka embryo-larval assay by sediment contact should be tested on a larger sample set, the results show that it is sensitive and convenient enough to monitor the toxicity of natural sediments. Environ Toxicol Chem 2016;35:2270-2280. © 2016 SETAC. © 2016 SETAC.

  4. Tethered by Self-Generated Flow: Mucus String Augmented Feeding Current Generation in Larval Oysters

    Science.gov (United States)

    Jiang, H.; Wheeler, J.; Anderson, E.

    2016-02-01

    Marine zooplankton live in a nutritionally dilute environment. To survive, they must process an enormous volume of water relative to their own body volume for food. To achieve this, many zooplankters including copepods, invertebrate larvae, and protists create a feeding current to concentrate and transport food items to their food gathering structures. To enhance the efficiency of the feeding current, these zooplankters often rely on certain "tethering" mechanisms to retard their translational motion for producing a strong feeding current. The tethering force may include excess weight due to gravity, force from attachment to solid surfaces, and drag experienced by strategically placed morphological structures. Larval oysters are known from previous studies to release mucus strings during feeding, presumably for supplying a tethering force to enhance their feeding-current efficiency. But the underlying mechanism is unclear. In this study, we used a high-speed microscale imaging system (HSMIS) to observe the behavior of freely swimming and feeding larval oysters. We also used HSMIS to measure larval imposed feeding currents via a micro-particle image velocimetry (µPIV) technique. HSMIS allows observations along a vertically oriented focal plane in a relatively large water vessel with unprecedented spatial and temporal resolutions. Our high-speed videos show that a feeding larval oyster continuously released a long mucus string into its feeding current that flows downward; the feeding current subsequently dragged the mucus string downward. Analysis of our µPIV data combined with a hydrodynamic model further suggests that the drag force experienced by the mucus string in the feeding current contributes significantly to the tethering force required to generate the feeding current. Thus, mucus strings in larval oysters act as "anchors" in larval self-generated flow to actively tether the feeding larvae.

  5. Efficiency of two larval diets for mass-rearing of the mosquito Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    J G Bond

    Full Text Available Aedes aegypti is a major vector of arboviruses that may be controlled on an area-wide basis using the sterile insect technique (SIT. Larval diet is a major factor in mass-rearing for SIT programs. We compared dietary effects on immature development and adult fitness-related characteristics for an International Atomic Energy Agency (IAEA diet, developed for rearing Ae. albopictus, and a standardized laboratory rodent diet (LRD, under a 14:10 h (light:dark photoperiod ("light" treatment or continuous darkness during larval rearing. Larval development was generally fastest in the IAEA diet, likely reflecting the high protein and lipid content of this diet. The proportion of larvae that survived to pupation or to adult emergence did not differ significantly between diets or light treatments. Insects from the LRD-dark treatment produced the highest proportion of male pupae (93% at 24 h after the beginning of pupation whereas adult sex ratio from the IAEA diet tended to be more male-biased than that of the LRD diet. Adult longevity did not differ significantly with larval diet or light conditions, irrespective of sex. In other aspects the LRD diet generally performed best. Adult males from the LRD diet were significantly larger than those from the IAEA diet, irrespective of light treatment. Females from the LRD diet had ~25% higher fecundity and ~8% higher egg fertility compared to those from the IAEA diet. Adult flight ability did not differ between larval diets, and males had a similar number of copulations with wild females, irrespective of larval diet. The LRD diet had lower protein and fat content but a higher carbohydrate and energetic content than the IAEA diet. We conclude that the LRD diet is a low-cost standardized diet that is likely to be suitable for mass-rearing of Ae. aegypti for area-wide SIT-based vector control.

  6. Passive larval transport explains recent gene flow in a Mediterranean gorgonian

    Science.gov (United States)

    Padrón, Mariana; Costantini, Federica; Baksay, Sandra; Bramanti, Lorenzo; Guizien, Katell

    2018-06-01

    Understanding the patterns of connectivity is required by the Strategic Plan for Biodiversity 2011-2020 and will be used to guide the extension of marine protection measures. Despite the increasing accuracy of ocean circulation modelling, the capacity to model the population connectivity of sessile benthic species with dispersal larval stages can be limited due to the potential effect of filters acting before or after dispersal, which modulates offspring release or settlement, respectively. We applied an interdisciplinary approach that combined demographic surveys, genetic methods (assignment tests and coalescent-based analyses) and larval transport simulations to test the relative importance of demographics and ocean currents in shaping the recent patterns of gene flow among populations of a Mediterranean gorgonian ( Eunicella singularis) in a fragmented rocky habitat (Gulf of Lion, NW Mediterranean Sea). We show that larval transport is a dominant driver of recent gene flow among the populations, and significant correlations were found between recent gene flow and larval transport during an average single dispersal event when the pelagic larval durations (PLDs) ranged from 7 to 14 d. Our results suggest that PLDs that efficiently connect populations distributed over a fragmented habitat are filtered by the habitat layout within the species competency period. Moreover, a PLD ranging from 7 to 14 d is sufficient to connect the fragmented rocky substrate of the Gulf of Lion. The rocky areas located in the centre of the Gulf of Lion, which are currently not protected, were identified as essential hubs for the distribution of migrants in the region. We encourage the use of a range of PLDs instead of a single value when estimating larval transport with biophysical models to identify potential connectivity patterns among a network of Marine Protected Areas or even solely a seascape.

  7. Radiation protection issues raised in Korea since Fukushima accident

    International Nuclear Information System (INIS)

    Kim, Byeongsoo

    2014-01-01

    For the past 3 years since Fukushima accident, various issues related to nuclear safety and radiation safety were raised in Korea. This presentation focuses radiation protection (RP) issues among the various issues and has the purpose to share experiences and lessons-learned related to the RP issues. Special safety inspections on NPPs in Korea were performed immediately after Fukushima accident and 50 follow-up measures were established in May, 2011 to improve the nuclear safety. Some of them were related to radiation protection and emergency responses. Recently, in March, 2014, additional follow-up measures were decided to be taken in additionally strengthening safety-related equipment and emergency response organization. The 50 Fukushima-accident-follow-up measures include radiation protection for members of the public in emergency responses. Based on the follow-up measures, expansion of emergency planning zone (EPZ) is to be made according to the approval of legislation by National Assembly on May 2, 2014. For the past 3 years, the degree of the public concerns on radiation risk has been the highest. Spontaneous activities for radiation monitoring happened in the public. Some members of the public found some contaminated paved roads in November, 2011 and a contaminated kitchen ware in January, 2012. These findings suggest the importance of the management of recycled metal scraps imported from other countries. Fukushima accident gave much impact on Korean society all. The public gets very sensitive to issues about nuclear safety and radiation safety. Most parts of RP issues raised are related to the public. The lessons-learned are that as an issue is raised, it has a chance to be solved. However, RP issues related to radiation workers in accident conditions in NPPs are difficult to be raised enough to confirm and improve the robustness of radiation protection programs in accident conditions. It is necessary to share RP issues raised in each country as well as

  8. Influence of swimming behavior of copepod nauplii on feeding of larval turbot (Scophthalmus maximus)

    DEFF Research Database (Denmark)

    Bruno, Eleonora; Højgaard, Jacob Kring; Hansen, Benni Winding

    2018-01-01

    Feeding in larval fish is influenced by a range of factors and among these are the morphological and behavioral characteristics of their prey. We investigated the influence of the swimming behavior of two species of calanoid copepods, Acartia tonsa and Temora longicornis, on larval turbot feeding....... The nauplii of these species represent two contrasting swimming behaviors: A. tonsa is a jump-sink type swimmer, while T. longicornis is a cruise swimming type. Three replicates of ten larvae aged 7 and 9 days post hatch (DPH) were observed feeding on one of the two copepod species using a 2-dimensional video...

  9. Process-based models of feeding and prey selection in larval fish

    DEFF Research Database (Denmark)

    Fiksen, O.; MacKenzie, Brian

    2002-01-01

    believed to be important to prey selectivity and environmental regulation of feeding in fish. We include the sensitivity of prey to the hydrodynamic signal generated by approaching larval fish and a simple model of the potential loss of prey due to turbulence whereby prey is lost if it leaves...... jig dry wt l(-1). The spatio-temporal fluctuation of turbulence (tidal cycle) and light (sun height) over the bank generates complex structure in the patterns of food intake of larval fish, with different patterns emerging for small and large larvae....

  10. Larval trophodynamics, turbulence, and drift on Georges Bank : A sensitivity analysis of cod and haddock

    DEFF Research Database (Denmark)

    Werner, F.E.; MacKenzie, Brian; Perry, R.I.

    2001-01-01

    Using an individual-based model approach we consider trophodynamic effects on the growth and survival of larval cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank during late winter/early spring. These studies represent an extension of results described in Werner et al. (1996...... be an important input to larval growth and survival models. The inclusion of turbulence in determining the position of passive larvae in the water column allows the larvae to sample the entire water column, contributing to a decrease in the variance of the size of the larvae over time. The ability of larvae...

  11. Biochemical changes during larval development in the short neck clam, Paphia malabarica Chemnitz

    Digital Repository Service at National Institute of Oceanography (India)

    Gireesh, R.; Biju, A.; Muthiah, P.

    larvae through feeding on organic particles and are subsequently used for supporting metamorphosis. (Rodriguez, Sedano, Garcia- Martin, Perez-Camacho & Sanchez 1990; Haws, DiMichele & Hand1993). During this stage, larval velum disap- pears, and larvae... on lipid class composition. Part II: larval rearing, competency and settlement. Journal of Shell¢sh Research 22, 377^388. RodriguezJ.L., SedanoF.J., Garcia-Martin L.O., Perez-Cama- choA. & SanchezJ.L. (1990) Energy metabolism of newly settled Ostrea edulis...

  12. Variability in growth rates of larval haddock in the northern North Sea

    DEFF Research Database (Denmark)

    Gallego, A.; Heath, M.R.; Basford, D.J.

    1999-01-01

    of the spring plankton production bloom, and a likely explanation for the absence of environmental effects on larval growth was high food availability and larval feeding rates. Nevertheless, differences in growth were observed between cohorts, with larvae hatched later in the spring displaying higher growth...... at age than those hatched earlier. Particle-tracking modelling suggested that differences in temperature history between cohorts, on their own or compounded by a potential interaction between temperature and the development of plankton production, may explain the higher growth rate of the larvae hatched...

  13. PATHOGENESIS OF OPTIC DISC EDEMA IN RAISED INTRACRANIAL PRESSURE

    Science.gov (United States)

    Hayreh, Sohan Singh

    2015-01-01

    Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with

  14. Larval growth in the dominant polychaete Polydora ciliata is food-limited in a eutrophic Danish estuary (Isefjord)

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Almeda, Rodrigo; Fotel, Frank Lech

    2010-01-01

    Food limitation in larval growth of the spionid polychaete Polydora ciliata was examined in a typical eutrophic estuary, Isefjord, in Denmark. In the field, food availability and the energetic requirements of the P. ciliata larval population were measured during 2 different periods in 2004 and 20...

  15. Measuring larval nematode contamination on cattle pastures: Comparing two herbage sampling methods.

    Science.gov (United States)

    Verschave, S H; Levecke, B; Duchateau, L; Vercruysse, J; Charlier, J

    2015-06-15

    Assessing levels of pasture larval contamination is frequently used to study the population dynamics of the free-living stages of parasitic nematodes of livestock. Direct quantification of infective larvae (L3) on herbage is the most applied method to measure pasture larval contamination. However, herbage collection remains labour intensive and there is a lack of studies addressing the variation induced by the sampling method and the required sample size. The aim of this study was (1) to compare two different sampling methods in terms of pasture larval count results and time required to sample, (2) to assess the amount of variation in larval counts at the level of sample plot, pasture and season, respectively and (3) to calculate the required sample size to assess pasture larval contamination with a predefined precision using random plots across pasture. Eight young stock pastures of different commercial dairy herds were sampled in three consecutive seasons during the grazing season (spring, summer and autumn). On each pasture, herbage samples were collected through both a double-crossed W-transect with samples taken every 10 steps (method 1) and four random located plots of 0.16 m(2) with collection of all herbage within the plot (method 2). The average (± standard deviation (SD)) pasture larval contamination using sampling methods 1 and 2 was 325 (± 479) and 305 (± 444)L3/kg dry herbage (DH), respectively. Large discrepancies in pasture larval counts of the same pasture and season were often seen between methods, but no significant difference (P = 0.38) in larval counts between methods was found. Less time was required to collect samples with method 2. This difference in collection time between methods was most pronounced for pastures with a surface area larger than 1 ha. The variation in pasture larval counts from samples generated by random plot sampling was mainly due to the repeated measurements on the same pasture in the same season (residual variance

  16. Vulnerability of larval lamprey to Columbia River hydropower system operations—effects of dewatering on larval lamprey movements and survival

    Science.gov (United States)

    Liedtke, Theresa L.; Weiland, Lisa K.; Mesa, Matthew G.

    2015-08-27

    Numbers of adult and juvenile Pacific lamprey ( Entosphenus tridentatus ) in the upper Columbia River Basin of the interior Pacific Northwest have decreased from historical levels (Close and others, 2002), raising concerns f rom State and Federal agencies and Tribal entities. In 1994, the U.S. Fish and Wildlife Service designated Pacific lamprey as a Category 2 candidate species and in 2003, the species was petitioned for listing under the Endangered Species Act. Listing consideration and potential recovery planning are significantly hindered by a lack of information on the basic biology and ecology of lampreys, including limiting factors. To date (2015), several factors that may limit lamprey production require study, including dam passage issues, contaminants, and effects on habitat.

  17. Perceived Autonomy Support in the NIMH RAISE Early Treatment Program.

    Science.gov (United States)

    Browne, Julia; Penn, David L; Bauer, Daniel J; Meyer-Kalos, Piper; Mueser, Kim T; Robinson, Delbert G; Addington, Jean; Schooler, Nina R; Glynn, Shirley M; Gingerich, Susan; Marcy, Patricia; Kane, John M

    2017-09-01

    This study examined perceived support for autonomy-the extent to which individuals feel empowered and supported to make informed choices-among participants in the Recovery After an Initial Schizophrenia Episode Early Treatment Program (RAISE ETP). The aims of this study were to evaluate whether NAVIGATE, the active treatment studied in RAISE ETP, was associated with greater improvements in perceived autonomy support over the two-year intervention, compared with community care, and to examine associations between perceived autonomy support and quality of life and symptoms over time and across treatment groups. This study examined perceived autonomy support among the 404 individuals with first-episode psychosis who participated in the RAISE ETP trial (NAVIGATE, N=223; community care, N=181). Three-level conditional linear growth modeling was used given the nested data structure. The results indicated that perceived autonomy support increased significantly over time for those in NAVIGATE but not in community care. Once treatment began, higher perceived autonomy support was related to higher quality of life at six, 12, and 18 months in NAVIGATE and at 12, 18, and 24 months in community care. Higher perceived autonomy support was related to improved scores on total symptoms and on excited symptoms regardless of treatment group and time. Overall, perceived autonomy support increased in NAVIGATE but not for those in community care and was related to improved quality of life and symptoms across both treatment groups. Future research should examine the impact of perceived autonomy support on a wider array of outcomes, including engagement, medication adherence, and functioning.

  18. Issues Raised in Relation to Radioactive Waste Management

    International Nuclear Information System (INIS)

    Atherton, Elizabeth

    2003-01-01

    Nirex has undertaken various consultations with different stakeholders to identify their issues and concerns about radioactive waste management in general and specific aspects of Nirex's work. This paper will outline what dialogue techniques Nirex has undertaken and the issues and concerns that people have raised during the events. It will outline some of the work that Nirex is undertaking to address stakeholders' issues and concerns. Nirex has used a variety of dialogue techniques co-ordinated under the Nirex Involvement Programme to engage with stakeholders about the work we undertake. We are now trying to address the issues, concerns, scenarios and questions raised in our work programme. Key lessons that we have learned in undertaking the dialogues include: The importance of appropriate facilitation and organisation of meetings; The need for a clear purpose for meetings; Being flexible to the needs of the attendees and the issues they raise; Providing feedback to those who participate and following up issues. Through engaging with the public Nirex has learned that: Radioactive waste is not an everyday concern for people; The public can, will and want to engage with the issue of radioactive waste management. This includes engaging with the ethical debate. To facilitate this Nirex and others need to: Provide information in a neutral form outlining the pros and cons and including various people's opinions; Use proactive techniques to allow access and space for people to discuss the issues; Demonstrate how people's opinions have been taken into account. People understand the issues very differently to the way institutions understand them. There is a need for institutions to learn to understand public concerns and the ways in which the public understand issues, as well as for the public to understand the institutional positions better. We are using these insights to develop our future work in this area

  19. Picture Book on Raising Children's Awareness Against Sexual Abuse

    OpenAIRE

    Christy, Evelyn; Handojo, Priska Febrinia

    2015-01-01

    One of the common problems leading to the sexual abuse is that the child is not aware about it. This project aims to raise children's awareness against sexual abuse through picture book. This picture book use realistic fiction as the genre of my picture book. The purpose is to make the children familiar with the story and can relate it to their life. This picture book uses the narrative theory as the framework of the story. The narrative story is consist of abstract, orientation, complication...

  20. Service use and unmet service needs in grandparents raising grandchildren.

    Science.gov (United States)

    Yancura, Loriena A

    2013-01-01

    Most in-depth studies of grandparents raising grandchildren use samples recruited from service providers, so little is known about those who do not use formal services. A sample of 200 grandparents registered with a public school district completed a survey on service use and unmet service needs. Of the 131 who did not use services, 82 reported unmet service needs, and 49 reported no needs. Those with unmet needs were younger, more likely to be Native Hawaiian, and less likely to receive public assistance. These findings indicate that some grandparents are falling through the cracks of the service provision network.

  1. Raising the efficiency of open-throttle liquefiers

    International Nuclear Information System (INIS)

    Zakharov, N.D.; Merkel', N.D.

    1986-01-01

    This paper makes a comparative thermodynamic analysis of certain open-throttle liquefier schemes that operate with multicomponent cryogenic agents. The most promising routes for implementing their advantages are determined. It is found that the correct choice of flow diagram and complex parameter optimization can raise the relative available energy (mass profile characteristics) of open-throttle liquefiers with mixtures to at least four times that of nitrogen installation. The most economical scheme is one that involves mixing the components in feedback, followed by double throttling of nitrogen

  2. Geochemical characteristics of peat from two raised bogs of Germany

    Science.gov (United States)

    Mezhibor, A. M.

    2016-11-01

    Peat has a wide range of applications in different spheres of human activity, and this is a reason for a comprehensive study. This research represents the results of an ICP-MS study of moss and peat samples from two raised bogs of Germany. Because of the wide use of sphagnum moss and peat, determining their geochemical characteristics is an important issue. According to the results obtained, we can resume that the moss samples from Germany are rich in Cu, As, Y, Zr, Nb, and REE. The geochemical composition of the bogs reflects the regional environmental features and anthropogenic influence.

  3. Tenneco raises $75 million for independents' E and P

    International Nuclear Information System (INIS)

    Land, R.

    1992-01-01

    Tenneco Gas's ventures group, Houston, has raised $75 million to invest in gas exploration and production by independent operations on the U.S. Gulf Coast. Institutional investors committed $50 million to the fund and a group of industrial investors $25 million. Tenneco the the fund will expand to accommodate additional investors through this year. This paper reports that the company's ventures group is evaluating acquisition and drilling opportunities with independents. Ventures group capital will be invested in independent exploratory, development, and producing properties

  4. Fund-raising strategies for the allied health professions.

    Science.gov (United States)

    Cornesky, R A; Anderson, J A

    1987-05-01

    Academic units of allied health (eg, schools and colleges of allied health) are relatively new to institutions of higher education. As a result, the academic units lack prestige with private funding sources. This article describes a development model for raising private contributions emphasizing allied health academic units. The roles of the academic department, development advisory committee, and faculty in developing the mission statement, needs, objectives, and case statement for the department are described. How the department chairperson, faculty, dean, and advisory committee members interact with the staff from a development office in identifying, cultivating, and soliciting private support are explained.

  5. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan; Wang, Hao; Qian, Peiyuan

    2012-01-01

    multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid

  6. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan; Zhang, Huoming; Wang, Hao; Matsumura, Kiyotaka; Wong, Yue Him; Ravasi, Timothy; Qian, Pei-Yuan

    2014-01-01

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  7. Effects of an increasing filter feeder stock on larval abundance in the Oosterschelde estuary (SW Netherlands)

    NARCIS (Netherlands)

    Troost, Karin; Gelderman, Edzard; Kamermans, Pauline; Smaal, Aad C.; Wolff, Wim J.

    Predation by adult bivalves oil bivalve larvae has been suggested to reduce larval abundance in areas with high bivalve filter-feeder biomass. Although the occurrence of larviphagy is well-studied in the laboratory, its effects in the field have scarcely been studied. We studied larviphagy at

  8. Effects of an increasing filter feeder stock on larval abundance in the Oosterschelde estuary (SW Netherlands)

    NARCIS (Netherlands)

    Troost, K.; Gelderman, E.A.C.; Kamermans, P.; Smaal, A.C.; Wolff, W.

    2009-01-01

    Predation by adult bivalves on bivalve larvae has been suggested to reduce larval abundance in areas with high bivalve filter-feeder biomass. Although the occurrence of larviphagy is well-studied in the laboratory, its effects in the field have scarcely been studied. We studied larviphagy at

  9. Differential growth of larval sprat Sprattus sprattus across a tidal front in the eastern North Sea

    DEFF Research Database (Denmark)

    Munk, Peter

    1993-01-01

    Spatial variations in abundance and growth of larval sprat Sprattus sprattus L. were examined across a tidal front in the eastern North Sea, off the west coast of Denmark. The aim of the study was to evaluate the potential advantage for sprat larvae of residing in the vicinity of a tidal front...

  10. Larval dispersion of the estuarine crab Neohelice granulata in coastal marine waters of the Southwest Atlantic

    Science.gov (United States)

    Bas, Claudia; Luppi, Tomás; Spivak, Eduardo; Schejter, Laura

    2009-08-01

    The estuarine brachyuran crab Neohelice granulata export their larvae from the parental intertidal population of the Mar Chiquita coastal lagoon, and probably other populations, to marine waters. The degree of larval dispersion or self-recruitment of populations is unknown. We evaluated the presence of all larval stages of N. granulata in coastal waters of Argentina between 37.9° and 35.8° S, at two different spatial scales: a broad scale of tens to hundreds of kilometers from the Río de la Plata estuary in the north, to Mar Chiquita lagoon in the south, and a small scale of hundreds of meters to some kilometers around the mouth of Mar Chiquita, during spring and summer. Additionally, we registered the larval composition and density at San Clemente creek population, in Samborombon Bay (Río de la Plata estuary), every 3 h along a 30-hour period. Evidence indicates that larval release of N. granulata is temporally synchronized with nocturnal ebb tides and all development from Zoea I to Zoea IV occur in areas close to the parental population, even with very different oceanographic characteristics. A possible mechanism based on salinity selection and wind-driven transport is proposed for such behavior, and some considerations related to the connectivity of present populations are made.

  11. Dioctophyma-like larval nematode in a subcutaneous nodule from man in Northern Thailand.

    Science.gov (United States)

    Beaver, P C; Khamboonruang, C

    1984-09-01

    A nematode in a subcutaneous nodule from the anterior chest of a 12-year-old boy in Northern Thailand was identified as a third-stage larval dioctophymatid, possibly Dioctophyma renale, the second such larva to be reported from man.

  12. Descripción del último estadio larval de Neofulla biloba (Plecoptera: Notonemouridae

    Directory of Open Access Journals (Sweden)

    Pablo PESSACQ

    2008-01-01

    Full Text Available Se describe el último estadio larval de Neofulla biloba (Aubert, desconocido para la ciencia. Se brindan caracteres morfológicos que lo separan de N. areolata (Navás, la única especie del género cuya larva ha sido descripta previamente.

  13. Influence of food concentration, temperature and salinity on the larval development of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Kurian, J.

    Influence of food concentration (0.5, 1 and 2 x 10 sup(5) cell ml sup(-1) of Skeletonema costatum), temperature (20 and 30 degrees C) and salinity (15, 25 and 35 ppt) on the larval development of Balanus amphitrite (Cirripedia: Thoracica...

  14. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan; Matsumura, Kiyotaka; Wang, Hao; Arellano, Shawn M.; Yan, Xingcheng; Alam, Intikhab; Archer, John A.C.; Bajic, Vladimir B.; Qian, Pei-Yuan

    2011-01-01

    of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval

  15. Properties of the Visible Light Phototaxis and UV Avoidance Behaviors in the Larval Zebrafish.

    Science.gov (United States)

    Guggiana-Nilo, Drago A; Engert, Florian

    2016-01-01

    For many organisms, color is an essential source of information from visual scenes. The larval zebrafish has the potential to be a model for the study of this topic, given its tetrachromatic retina and high dependence on vision. In this study we took a step toward understanding how the larval zebrafish might use color sensing. To this end, we used a projector-based paradigm to force a choice of a color stimulus at every turn of the larva. The stimuli used spanned most of the larval spectral range, including activation of its Ultraviolet (UV) cone, which has not been described behaviorally before. We found that zebrafish larvae swim toward visible wavelengths (>400 nm) when choosing between them and darkness, as has been reported with white light. However, when presented with UV light and darkness zebrafish show an intensity dependent avoidance behavior. This UV avoidance does not interact cooperatively with phototaxis toward longer wavelengths, but can compete against it in an intensity dependent manner. Finally, we show that the avoidance behavior depends on the presence of eyes with functional UV cones. These findings open future avenues for studying the neural circuits that underlie color sensing in the larval zebrafish.

  16. The wings of Bombyx mori develop from larval discs exhibiting an ...

    Indian Academy of Sciences (India)

    Unknown

    presumptive wing blade domains unlike in Drosophila, where it is confined to the hinge and the wing pouch. ... events are different and the wing discs behave like presumptive wing buds .... emerge with the fore- and the hind-wings (figure 1e, j) on ... phosis (compare c with d, and h with i) during the larval to pupal transition.

  17. Diel and tidal variations in larval fish exchange in the mouth region ...

    African Journals Online (AJOL)

    Diel and tidal variations in density of larval fishes were monitored over one neap and one spring tidal cycle in the mouth region of the warm temperate Gamtoos Estuary, South Africa. Data were collected over two 24h periods, using mixed method sampling with WP2 nets and a pushnet to sample both channel and margin ...

  18. Pheromone modulates two phenotypically plastic traits - adult reproduction and larval diapause - in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Wharam, Barney; Weldon, Laura; Viney, Mark

    2017-08-22

    Animals use information from their environment to make decisions, ultimately to maximize their fitness. The nematode C. elegans has a pheromone signalling system, which hitherto has principally been thought to be used by worms in deciding whether or not to arrest their development as larvae. Recent studies have suggested that this pheromone can have other roles in the C. elegans life cycle. Here we demonstrate a new role for the C. elegans pheromone, showing that it accelerates hermaphrodites' reproductive rate, a phenomenon which we call pheromone-dependent reproductive plasticity (PDRP). We also find that pheromone accelerates larval growth rates, but this depends on a live bacterial food source, while PDRP does not. Different C. elegans strains all show PDRP, though the magnitude of these effects differ among the strains, which is analogous to the diversity of arrested larval phenotypes that this pheromone also induces. Using a selection experiment we also show that selection for PDRP or for larval arrest affects both the target and the non-target trait, suggesting that there is cross-talk between these two pheromone-dependent traits. Together, these results show that C. elegans' pheromone is a signal that acts at two key life cycle points, controlling alternative larval fates and affecting adult hermaphrodites' reproduction. More broadly, these results suggest that to properly understand and interpret the biology of pheromone signalling in C. elegans and other nematodes, the life-history biology of these organisms in their natural environment needs to be considered.

  19. Patterns and persistence of larval retention and connectivity in a marine fish metapopulation

    KAUST Repository

    Saenz Agudelo, Pablo

    2012-08-14

    Connectivity, the demographic linking of local populations through the dispersal of individuals, is one of the most poorly understood processes in population dynamics, yet has profound implications for conservation and harvest strategies. For marine species with pelagic larvae, direct estimation of connectivity remains logistically challenging and has mostly been limited to single snapshots in time. Here, we document seasonal and interannual patterns of larval dispersal in a metapopulation of the coral reef fish Amphiprion polymnus. A 3-year record of larval trajectories within and among nine discrete local populations from an area of approximately 35 km was established by determining the natal origin of settled juveniles through DNA parentage analysis. We found that spatial patterns of both self-recruitment and connectivity were remarkably consistent over time, with a low level of self-recruitment at the scale of individual sites. Connectivity among sites was common and multidirectional in all years and was not significantly influenced by seasonal variability of predominant surface current directions. However, approximately 75% of the sampled juveniles could not be assigned to parents within the study area, indicating high levels of immigrations from sources outside the study area. The data support predictions that the magnitude and temporal stability of larval connectivity decreases significantly with increasing distance between subpopulations, but increases with the size of subpopulations. Given the considerable effort needed to directly measure larval exchange, the consistent patterns suggest snapshot parentage analyses can provide useful dispersal estimates to inform spatial management decisions. © 2012 Blackwell Publishing Ltd.

  20. Correlating Whole Brain Neural Activity with Behavior in Head-Fixed Larval Zebrafish.

    Science.gov (United States)

    Orger, Michael B; Portugues, Ruben

    2016-01-01

    We present a protocol to combine behavioral recording and imaging using 2-photon laser-scanning microscopy in head-fixed larval zebrafish that express a genetically encoded calcium indicator. The steps involve restraining the larva in agarose, setting up optics that allow projection of a visual stimulus and infrared illumination to monitor behavior, and analysis of the neuronal and behavioral data.

  1. Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.

    Directory of Open Access Journals (Sweden)

    Laith Yakob

    Full Text Available Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs. In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.

  2. Neuroendocrine control of Drosophila larval light preference

    DEFF Research Database (Denmark)

    Yamanaka, Naoki; Romero, Nuria M.; Martin, Francisco A.

    2013-01-01

    melanogaster larvae. PTTH, through its receptor Torso, acts on two light sensors???the Bolwig???s organ and the peripheral class IV dendritic arborization neurons???to regulate light avoidance. We found that PTTH concomitantly promotes steroidogenesis and light avoidance at the end of larval stage, driving...

  3. Composition and diversity of larval fish in the mangrove estuarine area of Marudu Bay, Sabah, Malaysia.

    Science.gov (United States)

    Rezagholinejad, Sadaf; Arshad, Aziz; Amin, S M Nurul; Ara, Roushon

    2016-07-01

    The composition of fish larvae and their diversity in different habitats are very important for fisheries management. Larval fishes were investigated in a mangrove estuary of Marudu Bay, Sabah, Malaysia from October 2012 to September 2013 at five different sites. Monthly samples of fish larvae were collected at five sampling sites by a plankton net with a mouth opening of 40.5 cm in diameter. In total, 3879 larval fish were caught in the investigated area. The mean density of ichthyoplankton at this area was 118 larvae/100 m(3). The fish larval assemblage comprised of 20 families whereas 13 families occurred at St1, 16 at St2, 16 at St3, 12 at St4 and 16 at St5. The top major families were Sillaginidae, Engraulidae, Mugilidae and Sparidae with Sillaginidae consisted 44% of total larval composition. St3 with 143 larvae/100 m(3) had the highest density amongst the stations which was due to higher abundance of Sillaginidae. Shannon-Wiener diversity index represented significant variation during monsoon and inter-monsoon seasons, peaking in the months December-January and May-June. However, Shannon-Wiener index, evenness and family richness showed significant differences among stations and months (p < 0.05).

  4. Response of larval sea lampreys (Petromyzon marinus) to pulsed DC electrical stimuli in laboratory experiments

    Science.gov (United States)

    Bowen, Anjanette K.; Weisser, John W.; Bergstedt, Roger A.; Famoye, Felix

    2003-01-01

    Four electrical factors that are used in pulsed DC electrofishing for larval sea lampreys (Petromyzon marinus) were evaluated in two laboratory studies to determine the optimal values to induce larval emergence over a range of water temperatures and conductivities. Burrowed larvae were exposed to combinations of pulsed DC electrical factors including five pulse frequencies, three pulse patterns, and two levels of duty cycle over a range of seven voltage gradients in two separate studies conducted at water temperatures of 10, 15, and 20°C and water conductivities of 25, 200, and 900 μS/cm. A four-way analysis of variance was used to determine significant (α = 0.05) influences of each electrical factor on larval emergence. Multiple comparison tests with Bonferroni adjustments were used to determine which values of each factor resulted in significantly higher emergence at each temperature and conductivity. Voltage gradient and pulse frequency significantly affected emergence according to the ANOVA model at each temperature and conductivity tested. Duty cycle and pulse pattern generally did not significantly influence the model. Findings suggest that a setting of 2.0 V/cm, 3 pulses/sec, 10% duty, and 2:2 pulse pattern seems the most promising in waters of medium conductivity and across a variety of temperatures. This information provides a basis for understanding larval response to pulsed DC electrofishing gear factors and identifies electrofisher settings that show promise to increase the efficiency of the gear during assessments for burrowed sea lamprey larvae.

  5. Feeding and growth of larval herring,Clupea harengus, in relation to density of copepod nauplii

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter

    1986-01-01

    Feeding and growth rates of 1–3 wk old herring larvae from four different stocks were compared in laboratory experiments (8°C). For most of the larval groups, feeding rate was saturated at nauplii (Acartia tonsa, nauplii stages 3–5) densities over 301−1 (5 μg d.w. 1−1). Specific growth rate incre...

  6. CONSUMPTIONS RATES OF SUMMER FLOUNDER LARVAE ON ROTIFER AND BRINE SHRIMP PREY DURING LARVAL REARING

    Science.gov (United States)

    Larval summer flounder Paralichthys dentatus were hatched and reared through metamorphosis in the laboratory. At several points in the rearing cycle, larvae were removed from their rearing chambers and placed in small bowls, where they were fed known quantities of the rotifer Bra...

  7. A review of postfeeding larval dispersal in blowflies: implications for forensic entomology

    Science.gov (United States)

    Gomes, Leonardo; Godoy, Wesley Augusto Conde; von Zuben, Claudio José

    2006-05-01

    Immature and adult stages of blowflies are one of the primary invertebrate consumers of decomposing animal organic matter. When the food supply is consumed or when the larvae complete their development and migrate prior to the total removal of the larval substrate, they disperse to find adequate places for pupation, a process known as postfeeding larval dispersal. Several important ecological and physiological aspects of this process were studied since the work by Green (Ann Appl Biol 38:475, 1951) 50 years ago. An understanding of postfeeding larval dispersal can be useful for determining the postmortem interval (PMI) of human cadavers in legal medicine, particularly because this interval may be underestimated if older dispersing larvae or those that disperse longer, faster, and deeper are not taken into account. In this article, we review the process of postfeeding larval dispersal and its implications for legal medicine, in particular showing that aspects such as burial behavior and competition among species of blowflies can influence this process and consequently, the estimation of PMI.

  8. Diel variation of larval fish abundance in the Amazon and Rio Negro

    Directory of Open Access Journals (Sweden)

    ARAUJO-LIMA C. A. R. M.

    2001-01-01

    Full Text Available Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.

  9. Diel variation of larval fish abundance in the Amazon and Rio Negro

    Directory of Open Access Journals (Sweden)

    C. A. R. M. ARAUJO-LIMA

    Full Text Available Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.

  10. Role of elongator subunit Elp3 in Drosophila melanogaster larval development and immunity

    DEFF Research Database (Denmark)

    Walker, Jane; Kwon, So Yeon; Badenhorst, Paul

    2011-01-01

    , larval growth is dramatically impaired, with progression to the third instar delayed for ~24 hr, and pupariation occurring only at day 14 after egg laying. Melanotic nodules appear after 4 days. Microarray analysis shows that stress response genes are induced and ecdysone-induced transcription factors...

  11. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2014-02-13

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  12. Larval Performance in the Context of Ecological Diversification and Speciation in Lycaeides Butterflies

    Directory of Open Access Journals (Sweden)

    Cynthia F. Scholl

    2012-01-01

    Full Text Available The role of ecology in diversification has been widely investigated, though few groups have been studied in enough detail to allow comparisons of different ecological traits that potentially contribute to reproductive isolation. We investigated larval performance within a species complex of Lycaeides butterflies. Caterpillars from seven populations were reared on five host plants, asking if host-specific, adaptive larval traits exist. We found large differences in performance across plants and fewer differences among populations. The patterns of performance are complex and suggest both conserved traits (i.e., plant effects across populations and more recent dynamics of local adaptation, in particular for L. melissa that has colonized an exotic host. We did not find a relationship between oviposition preference and larval performance, suggesting that preference did not evolve to match performance. Finally, we put larval performance within the context of several other traits that might contribute to ecologically based reproductive isolation in the Lycaeides complex. This larger context, involving multiple ecological and behavioral traits, highlights the complexity of ecological diversification and emphasizes the need for detailed studies on the strength of putative barriers to gene flow in order to fully understand the process of ecological speciation.

  13. Microbial gut diversity of Africanized and European honey bee larval instars.

    Directory of Open Access Journals (Sweden)

    Svjetlana Vojvodic

    Full Text Available The first step in understanding gut microbial ecology is determining the presence and potential niche breadth of associated microbes. While the core gut bacteria of adult honey bees is becoming increasingly apparent, there is very little and inconsistent information concerning symbiotic bacterial communities in honey bee larvae. The larval gut is the target of highly pathogenic bacteria and fungi, highlighting the need to understand interactions between typical larval gut flora, nutrition and disease progression. Here we show that the larval gut is colonized by a handful of bacterial groups previously described from guts of adult honey bees or other pollinators. First and second larval instars contained almost exclusively Alpha 2.2, a core Acetobacteraceae, while later instars were dominated by one of two very different Lactobacillus spp., depending on the sampled site. Royal jelly inhibition assays revealed that of seven bacteria occurring in larvae, only one Neisseriaceae and one Lactobacillus sp. were inhibited. We found both core and environmentally vectored bacteria with putatively beneficial functions. Our results suggest that early inoculation by Acetobacteraceae may be important for microbial succession in larvae. This assay is a starting point for more sophisticated in vitro models of nutrition and disease resistance in honey bee larvae.

  14. Barnacle larval transport in the Mandovi–Zuari estuarine system, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    George, G.; Desai, D.V.; Gaonkar, C.A.; Aboobacker, V.M.; Vethamony, P.; Anil, A.C.

    Santos A, Dubert J, González-Gordillo JI, Paula J, Peliz A, Santos AMP (2007) Oceanographic and behavioural processes affecting invertebrate larval dispersal and supply in the western Iberia upwelling ecosystem. Prog Oceanogr 74:174-191 Roff JC, Pett...

  15. Nestedness patterns of container-dwelling mosquitoes: Effects of larval habitat within variable terrestial matrices

    Science.gov (United States)

    Distributions of mosquito larvae likely are a consequence of multiple factors, although two commonly studied factors (quality of the larval environment and the terrestrial matrix in which these habitats reside) have rarely and simultaneously been varied in the field to understand...

  16. Proteolytic activity regarding Sarconesiopsis magellanica (Diptera: Calliphoridae) larval excretions and secretions.

    Science.gov (United States)

    Pinilla, Yudi T; Moreno-Pérez, Darwin A; Patarroyo, Manuel A; Bello, Felio J

    2013-12-01

    Sarconesiopsis magellanica (Diptera: Calliphoridae) is a medically important necrophagous fly which is used for establishing the post-mortem interval. Diptera maggots release proteolytic enzymes contained in larval excretion and secretion (ES) products playing a key role in digestion. Special interest in proteolytic enzymes has also been aroused regarding understanding their role in wound healing since they degrade necrotic tissue during larval therapy. This study was thus aimed at identifying and characterising S. magellanica proteolytic enzyme ES products for the first time. These products were obtained from first-, second- and third-instar larvae taken from a previously-established colony. ES proteins were separated by SDS-PAGE and their proteolytic activity was characterised by zymograms and inhibition assays involving BAPNA (Nα-benzoyl-dl-Arg-p-nitroanilide) and SAPNA substrates, using synthetic inhibitors. The protein profile ranged from ∼69kDa to ∼23kDa; several of them coincided with the Lucilia sericata ES protein profile. Serine-protease hydrolysis activity (measured by zymogram) was confirmed when a ∼25kDa band disappeared upon ES incubation with PMSF inhibitor at pH 7.8. Analysis of larval ES proteolytic activity on BAPNA and SAPNA substrates (determined by using TLCK and TPCK specific inhibitors) suggested a greater amount of trypsin-like protease. These results support the need for further experiments aimed at validating S. magellanica use in larval therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Age- and Wavelength-Dependency of Drosophila Larval Phototaxis and Behavioral Responses to Natural Lighting Conditions

    Directory of Open Access Journals (Sweden)

    Simon G. Sprecher

    2017-04-01

    Full Text Available Animals use various environmental cues as key determinant for their behavioral decisions. Visual systems are hereby responsible to translate light-dependent stimuli into neuronal encoded information. Even though the larval eyes of the fruit fly Drosophila melanogaster are comparably simple, they comprise two types of photoreceptor neurons (PRs, defined by different Rhodopsin genes expressed. Recent findings support that for light avoidance Rhodopsin5 (Rh5 expressing photoreceptors are crucial, while Rhodopsin6 (Rh6 expressing photoreceptors are dispensable under laboratory conditions. However, it remains debated how animals change light preference during larval live. We show that larval negative phototaxis is age-independent as it persists in larvae from foraging to wandering developmental stages. Moreover, if spectrally different Rhodopsins are employed for the detection of different wavelength of light remains unexplored. We found that negative phototaxis can be elicit by light with wavelengths ranging from ultraviolet (UV to green. This behavior is uniquely mediated by Rh5 expressing photoreceptors, and therefore suggest that this photoreceptor-type is able to perceive UV up to green light. In contrast to laboratory our field experiments revealed that Drosophila larvae uses both types of photoreceptors under natural lighting conditions. All our results, demonstrate that Drosophila larval eyes mediate avoidance of light stimuli with a wide, ecological relevant range of quantity (intensities and quality (wavelengths. Thus, the two photoreceptor-types appear more likely to play a role in different aspects of phototaxis under natural lighting conditions, rather than color discrimination.

  18. Metabolism of labelled proteins of bombicid moth hemolymph at the final stage of its larval development

    Energy Technology Data Exchange (ETDEWEB)

    Klunova, S M; Altsybeeva, T I; Filippovich, Yu B [Moskovskij Gosudarstvennyj Pedagogicheskij Inst. (USSR)

    1980-01-01

    Studied was the distribution of radioactivity among hemolymph total proteins, fat body, carcass, intestinal wall, febroin and sericin sections of the silk gland after a single injection of hemolymph radioactive preparation into a bombyx. The fat body was the place of the synthesis of proteins used for silk protein formation at the end of 5-larval age.

  19. Investigating phenology of larval fishes in St. Louis River estuary shallow water habitats

    Science.gov (United States)

    As part of the development of an early detection monitoring strategy for non-native fishes, larval fish surveys have been conducted since 2012 in the St. Louis River estuary. Survey data demonstrates there is considerable variability in fish abundance and species assemblages acro...

  20. Leaseback: An alternative source to raise company working capital

    Directory of Open Access Journals (Sweden)

    Laušević Ljubica

    2014-01-01

    Full Text Available This paper offers a description, regulatory framework and the manner of implementation of the leaseback as an alternative manner of raising working capital for companies with a large number and type of users. Leaseback has experienced an explosive growth in Europe, in the first decade of this century, especially during the years of economic prosperity. The value of leaseback in Europe has grown from 6.9 billion EUR in 2004, up to 46 billion EUR in 2007, i.e. during the four years the value was increased for 567%. Leaseback has shown itself to be, according to the analyses made, an 'ideal' manner of financing based on sale-and-leaseback of real estate. Capital that is 'immobilised' on long-term basis, through the leaseback regains its quality of capital ready to be engaged in current activities, i.e. projects and programmes of companies that are making high earnings. The objective of this work is to draw the attention, on the basis of a comprehensive theoretical presentation, empirical analyses and positive world practices, to this, in our business circumstances, a completely novel manner of financing, in the context of raising additional working capital through the inflow of both the domestic and of the foreign capital in Serbia. In order to achieve full implementation of this type of financing, it is necessary to overcome a number of constraints and provide regulatory framework, developed investment funds for investment in real estate, and a properly set in place cadastre register.

  1. Civil engineering work to raise the level of Route Goward

    CERN Multimedia

    2013-01-01

    Civil engineering work to raise the level of Route Goward will take place during Long Shutdown 1. The work will begin on 18 March 2013 and is expected to last around 5 months.   Route Goward runs over the top of the PS tunnel and is the only access route to the inside of the ring. The layer of shielding backfill beneath this road is the thinnest anywhere on the PS ring. As the purpose of this shielding is to protect against the ionising radiation emitted by the accelerator when in operation, this road has been classified as a “supervised radiation area” according to radiation protection regulations. This classification was merely a temporary solution and, on the recommendation of the PS Radiation Working Group (PSRWG), the decision has been taken to raise the surface level permanently by around 2 m in order to increase the thickness of the shielding and thus lower the dose rate to that of a non-designated area. As the PS tunnel itself is unable to withstand the weight of t...

  2. [Hematopoietic cells raising with plerixafor in non-Hodgkin lymphoma].

    Science.gov (United States)

    Pérez-Lozano, Uendy; Tripp-Villanueva, Francisco; Ramírez-Alvarado, Aline; Vela-Ojeda, Jorge; Limón-Flores, Alejandro; Kramis-Cerezo, José Luis

    2012-01-01

    bone marrow autologous transplantation (BMAT) has proven benefits in patients treated for non-Hodgkin's lymphoma (NHL). Plerixafor is an inhibitor of CXCR4 receptor. The aim was to report the raise of hematopoietic cells with plerixafor in patients with NHL. patient 1 with follicular NHL, GI, intermediate FLIPI, CD20+, CD45+, BCL-2+, who reached complete response after three chemotherapy regimes. Mobilization failed after use of filgrastim (G-CSF) alone and G-CSF + cyclophosphamide. A new attempt was made with G-CSF + plerixafor (G-CSF, 10 μg/kg for 7 days + plerixafor, 240 μg/kg in days 4 to 7). Patient 2 with follicular NHL and CD20+ reached complete remission with MINE after therapeutic failure with other regimes, but develops severe marrow toxicity. Mobilization was supported with G-CSF 10 μg/kg/d + plerixafor in days 4 and 5. In case one, proper cell counts where obtained after three aphaeresis. In the second case, two harvests add of 2.7 × 106/kg were obtained. plerixafor raised the hematopoietic stem cells in peripheral blood and improves mobilization of proper cell population.

  3. Carbon dioxide emission from raised bog surface after peat extraction

    Directory of Open Access Journals (Sweden)

    Turbiak Janusz

    2017-12-01

    Full Text Available Research on CO2 emission from a raised bog after completion of peat extraction was performed in 2011–2013. CO2 emissions were determined by the chamber method. Twenty years after the termination of peat extraction, the bog surface was almost entirely devoid of plants. CO2 emission from the bog varied depending on temperature and water conditions and was 418 mg·m−2·h−1 on average during the research period. CO2 losses on the raised bog were on average 19.7 Mg·ha−1·year−1 during the research period which corresponded to a carbon loss of 5.37 Mg·ha−1·year−1 or mineralisation of 9.6 Mg·ha−1·year−1 of organic mass of 56% carbon content. It is possible to reduce organic mass losses and CO2 emission to the atmosphere from the bog surface after peat extraction has been terminated by reconstruction of initial water conditions, i.e. retaining a high ground water level and restoration of aquatic plant communities.

  4. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    KAUST Repository

    He, Li-Sheng

    2012-10-24

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts.

  5. Habitat use by larval fishes in a temperate South African surf zone

    Science.gov (United States)

    Watt-Pringle, Peter; Strydom, Nadine A.

    2003-12-01

    Larval fishes were sampled in the Kwaaihoek surf zone on the south east coast of South Africa. On six occasions between February and May 2002, larval fishes were collected in two habitat types identified in the inner surf zone using a modified beach-seine net. The surf zone habitats were classified as either sheltered trough areas or adjacent exposed surf areas. Temperature, depth and current measurements were taken at all sites. Trough habitats consisted of a depression in surf topography characterised by reduced current velocities and greater average depth than adjacent surf areas. In total, 325 larval fishes were collected. Of these, 229 were collected in trough and 96 in surf habitats. At least 22 families and 37 species were represented in the catch. Dominant families were the Mugilidae, Sparidae, Atherinidae, and Engraulidae. Dominant species included Liza tricuspidens and Liza richardsonii (Mugilidae), Rhabdosargus holubi and Sarpa salpa (Sparidae), Atherina breviceps (Atherinidae) and Engraulis japonicus (Engraulide). Mean CPUE of postflexion larvae of estuary-dependent species was significantly greater in trough areas. The proportion of postflexion larval fishes in trough habitat was significantly greater than that of preflexion stages, a result that was not apparent in surf habitat sampled. CPUE of postflexion larvae of estuary-dependent fishes was negatively correlated with current magnitude and positively correlated with habitat depth. Mean body length of larval fishes was significantly greater in trough than in surf habitats. These results provide evidence that the CPUE of postflexion larvae of estuary-dependent fishes is higher in trough habitat in the surf zone and this may be indicative of active habitat selection for areas of reduced current velocity/wave action. The implications of this behaviour for estuarine recruitment processes are discussed.

  6. Influence of larval and pupal products on the oviposition behavior of Aedes Fluviatilis (Lutz (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Rotraut A. G. B. Consoli

    1988-06-01

    Full Text Available Several larval and pupal products of Aedes fluviatilis (Lutz were tested for their influence on the oviposition behaviour of females of the same species. Significant (alfa = 0,05 atractiveness was shown by: larval water, previously containing 5 to 15 larvae/1,5 ml; larval water, preserved up to 38 days; evaporate and reconstructed larval water extracts up to 2 years after production and water filtered through fresh or dried ground larvae. hexanic larval water extracts and water filtered through fresh or dired ground pupae did not influence oviposition.Estudou-se a influência sobre o comportamento de oviposição das fêmeas de Aedes fluviatilis (Lutz de produtos derivados das formas imaturas da mesma espécie. As fêmeas foram atraídas significativamente (x=0,05 por ocasião da ovoposição por: água destilada que contivera 5 ou 15 larvas/1,5 ml, a mesma água (5 larvas/1,5 mlapós sua preservação por 38 dias; extratos evaporados e reconstituídos de água que conteve larvas, por até dois anos a sua produção, e filtrados de macerados frescos e secos de larvas. Extratos hexânicos de água que conteve larvas e filtrados de macerados descos e secos de pupas não atraíram a ovoposição das fêmeas.

  7. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    KAUST Repository

    He, Li-Sheng; Xu, Ying; Matsumura, Kiyotaka; Zhang, Yu; Zhang, Gen; Qi, Shu-Hua; Qian, Pei-Yuan

    2012-01-01

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts.

  8. Live Cell Imaging of Butterfly Pupal and Larval Wings In Vivo.

    Directory of Open Access Journals (Sweden)

    Yoshikazu Ohno

    Full Text Available Butterfly wing color patterns are determined during the late larval and early pupal stages. Characterization of wing epithelial cells at these stages is thus critical to understand how wing structures, including color patterns, are determined. Previously, we successfully recorded real-time in vivo images of developing butterfly wings over time at the tissue level. In this study, we employed similar in vivo fluorescent imaging techniques to visualize developing wing epithelial cells in the late larval and early pupal stages 1 hour post-pupation. Both larval and pupal epithelial cells were rich in mitochondria and intracellular networks of endoplasmic reticulum, suggesting high metabolic activities, likely in preparation for cellular division, polyploidization, and differentiation. Larval epithelial cells in the wing imaginal disk were relatively large horizontally and tightly packed, whereas pupal epithelial cells were smaller and relatively loosely packed. Furthermore, larval cells were flat, whereas pupal cells were vertically elongated as deep as 130 μm. In pupal cells, many endosome-like or autophagosome-like structures were present in the cellular periphery down to approximately 10 μm in depth, and extensive epidermal feet or filopodia-like processes were observed a few micrometers deep from the cellular surface. Cells were clustered or bundled from approximately 50 μm in depth to deeper levels. From 60 μm to 80 μm in depth, horizontal connections between these clusters were observed. The prospective eyespot and marginal focus areas were resistant to fluorescent dyes, likely because of their non-flat cone-like structures with a relatively thick cuticle. These in vivo images provide important information with which to understand processes of epithelial cell differentiation and color pattern determination in butterfly wings.

  9. Live Cell Imaging of Butterfly Pupal and Larval Wings In Vivo.

    Science.gov (United States)

    Ohno, Yoshikazu; Otaki, Joji M

    2015-01-01

    Butterfly wing color patterns are determined during the late larval and early pupal stages. Characterization of wing epithelial cells at these stages is thus critical to understand how wing structures, including color patterns, are determined. Previously, we successfully recorded real-time in vivo images of developing butterfly wings over time at the tissue level. In this study, we employed similar in vivo fluorescent imaging techniques to visualize developing wing epithelial cells in the late larval and early pupal stages 1 hour post-pupation. Both larval and pupal epithelial cells were rich in mitochondria and intracellular networks of endoplasmic reticulum, suggesting high metabolic activities, likely in preparation for cellular division, polyploidization, and differentiation. Larval epithelial cells in the wing imaginal disk were relatively large horizontally and tightly packed, whereas pupal epithelial cells were smaller and relatively loosely packed. Furthermore, larval cells were flat, whereas pupal cells were vertically elongated as deep as 130 μm. In pupal cells, many endosome-like or autophagosome-like structures were present in the cellular periphery down to approximately 10 μm in depth, and extensive epidermal feet or filopodia-like processes were observed a few micrometers deep from the cellular surface. Cells were clustered or bundled from approximately 50 μm in depth to deeper levels. From 60 μm to 80 μm in depth, horizontal connections between these clusters were observed. The prospective eyespot and marginal focus areas were resistant to fluorescent dyes, likely because of their non-flat cone-like structures with a relatively thick cuticle. These in vivo images provide important information with which to understand processes of epithelial cell differentiation and color pattern determination in butterfly wings.

  10. Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

    Directory of Open Access Journals (Sweden)

    Peter W Alderks

    Full Text Available The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2 = 0.92. The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis. Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

  11. Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

    Science.gov (United States)

    Alderks, Peter W; Sisneros, Joseph A

    2013-01-01

    The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2) = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

  12. Composition and temporal patterns of larval fish communities in Chesapeake and Delaware Bays

    Directory of Open Access Journals (Sweden)

    Filipe Ribeiro

    2015-11-01

    Full Text Available Comparing larval fish assemblages in different estuaries provides insights about the coastal distribution of larval populations, larval transport, and adult spawning locations (Ribeiro et al. 2015. We simultaneously compared the larval fish assemblages entering two Middle Atlantic Bight (MAB estuaries (Delaware Bay and Chesapeake Bay, USA through weekly sampling from 2007 to 2009. In total, 43 taxa (32 families and 36 taxa (24 families were collected in Delaware and Chesapeake Bays, respectively. Mean taxonomic diversity, mean richness, and evenness were generally lower in Delaware Bay. Communities of both bays were dominated by Anchoa spp., Gobiosoma spp., Micropogonias undulatus, and Brevoortia tyrannus; Paralichthys spp. was more abundant in Delaware Bay and Microgobius thalassinus was more abundant in Chesapeake Bay. Inter-annual variation in the larval fish communities was low at both sites, with a relatively consistent composition across years, but strong seasonal (intra-annual variation in species composition occurred in both bays. Two groups were identified in Chesapeake Bay: a ‘winter’ group dominated by shelf-spawned species (e.g. M. undulatus and a ‘summer’ group comprising obligate estuarine species and coastal species (e.g. Gobiosoma spp. and Cynoscion regalis, respectively. In Delaware Bay, 4 groups were identified: a ‘summer’ group of mainly obligate estuarine fishes (e.g. Menidia sp. being replaced by a ‘fall’ group (e.g. Ctenogobius boleosoma and Gobionellus oceanicus; ‘winter’ and ‘spring’ groups were dominated by shelf-spawned (e.g. M. undulatus and Paralichthys spp. and obligate estuarine species (e.g. Leiostomus xanthurus and Pseudopleuronectes americanus, respectively. This study demonstrates that inexpensive and simultaneous sampling in different estuaries provides important insights into the variability in community structure of fish assemblages at large spatial scales.

  13. Larval gizzard shad characteristics in Lake Oahe, South Dakota: A species at the northern edge of its range

    Science.gov (United States)

    Fincel, Mark J.; Chipps, Steven R.; Graeb, Brian D. S.; Edwards, Kris R.

    2013-01-01

    Gizzard shad, Dorosoma cepedianum, have generally been restricted to the lower Missouri River impoundments in South Dakota. In recent years, gizzard shad numbers have increased in Lake Oahe, marking the northern-most natural population. These increases could potentially affect recreational fishes. Specifically, questions arise about larval gizzard shad growth dynamics and if age-0 gizzard shad in Lake Oahe will exhibit fast or slow growth, both of which can have profound effects on piscivore populations in this reservoir. In this study, we evaluated larval gizzard shad hatch timing, growth, and density in Lake Oahe. We collected larval gizzard shad from six sites from May to July 2008 and used sagittal otoliths to estimate the growth and back-calculate the hatch date. We found that larval gizzard shad hatched earlier in the upper part of the reservoir compared to the lower portion and that hatch date appeared to correspond to warming water temperatures. The peak larval gizzard shad density ranged from 0.6 to 33.6 (#/100 m3) and varied significantly among reservoir sites. Larval gizzard shad growth ranged from 0.24 to 0.57 (mm/d) and differed spatially within the reservoir. We found no relationship between the larval gizzard shad growth or density and small- or large-bodied zooplankton density (p > 0.05). As this population exhibits slow growth and low densities, gizzard shad should remain a suitable forage option for recreational fishes in Lake Oahe.

  14. Sampling uncharted waters: Examining rearing habitat of larval Longfin Smelt (Spirinchus thaleichthys) in the upper San Francisco Estuary

    Science.gov (United States)

    Grimaldo, Lenny; Feyrer, Frederick; Burns, Jillian; Maniscalco, Donna

    2017-01-01

    The southern-most reproducing Longfin Smelt population occurs in the San Francisco Estuary, California, USA. Long-term monitoring of estuarine habitat for this species has generally only considered deep channels, with little known of the role shallow waters play in supporting their early life stage. To address the need for focused research on shallow-water habitat, a targeted study of Longfin Smelt larvae in littoral habitat was conducted to identify potential rearing habitats during 2013 and 2014. Our study objectives were to (1) determine if larval densities vary between littoral habitats (tidal slough vs. open-water shoal), (2) determine how larval densities in littoral habitats vary with physicochemical and biological attributes, (3) determine if larval densities vary between littoral habitats and long-term monitoring channel collections, and (4) determine what factors predict larval rearing distributions from the long-term monitoring channel collections. Larval densities did not vary between littoral habitats but they did vary between years. Water temperature, salinity, and chlorophyll a were found important in predicting larval densities in littoral habitats. Larval densities do not vary between littoral and channel surveys; however, the analysis based on channel data suggests that Longfin Smelt are hatching and rearing in a much broader region and under higher salinities (∼2–12 psu) than previously recognized. Results of this study indicate that conservation efforts should consider how freshwater flow, habitat, climate, and food webs interact as mechanisms that influence Longfin Smelt recruitment in estuarine environments.

  15. [Louis Braille (1809-1852)--inventor of raised dots system].

    Science.gov (United States)

    Maciejewicz, Piotr; Kopacz, Dorota

    2005-01-01

    Louis Braille was born on January 4th 1809 in Coupvray, France. An injury to his eye at the age of three, resulted in total loss of vision. In 1819 he entered the Institute for Blind Youth in Paris. There he would live, study, and later teach. When he was fifteen, he developed system of reading and writing by means of raised dots, which is known today as Braille. The basis of the Braille system is known as a Braille cell. The cell is comprised of six dots numbered in a specific order. Each dot or combination of dots represents a letter of the alphabet. This Braille system has established itself internationally and formed the basic Braille for all languages.

  16. RAISING YOUNG LEARNERS‟ AWARENESS OF GRAMMAR THROUGH CREATIVE LANGUAGE ACTIVITIES

    Directory of Open Access Journals (Sweden)

    C. Murni Wahyanti

    2017-04-01

    Full Text Available Current developments in foreign language teaching have shown the need to reconsider the role of grammar. It is argued that grammar understanding can promote more precise use of the foreign language. This belief has led to an increased interest in grammar teaching, including grammar teaching for young learners. In teaching English to young learners, activities that can promote grammar awareness are needed. The activities should be presented in context to make sure that the meaning is clear. The activities should also be creatively designed in order to challenge students‘ motivation and involvement. Grammar activities presented creatively in meaningful contexts are useful for noticing the language patterns. This paper focuses on the changing status of grammar, the importance of grammar in the young learner classroom, and how to raise grammar awareness through creative language activities. It also reports the result of a small-scale study on implementing grammarawareness activities for teaching English to Elementary School students.

  17. Raise the management level of EPC contracting in six aspects

    International Nuclear Information System (INIS)

    Wang Baowei; Feng Shoujia

    2010-01-01

    Nuclear power construction develops rapidly today and EPC contracting for nuclear power projects, as a strategic decision of CNNC, has become a tendency. The target of engineering management can be smoothly realized or achieved by doing a good job in the following six aspects: effective communication between divisions of project department, high-degree consistency of managerial concepts for project management staff, clear objective for different divisions in the project department, presence of rules to be observed in construction management work, avoidance of human-initiated errors in the project, and clear distinction of management control concept. It is hoped that, through exchange and practice, management procedures and consciousness for EPC contracting can be further standardized and thus the level of management for EPC contracting will be raised finally. (authors)

  18. Raise the management level of EPC contracting in six aspects

    International Nuclear Information System (INIS)

    Wang Baowei; Feng Shoujia

    2010-01-01

    Nuclear power construction develops rapidly today and EPC contracting for nuclear power projects, as a strategic decision of CNNC, has become a tendency. The target of engineering management can be smoothly realized or achieved by doing a good job in the following six aspects:effective communication between divisions of project department, high-degree consistency of managerial concepts for project management staff, clear objective for different divisions in the project department, presence of rules to be observed in construction management work, avoidance of human-initiated errors in the project, and clear distinction of management control concept. It is hoped that, through exchange and practice, management procedures and consciousness for EPC contracting can be further standardized and thus the level of management for EPC contracting will be raised finally. (authors)

  19. THE CHALLENGES OF RAISING REVENUES AND RESTRUCTURING SUBSIDIES IN MALAYSIA

    Directory of Open Access Journals (Sweden)

    Suresh Narayanan

    2007-01-01

    Full Text Available Malaysia has run deficit budgets in all but five years since 1970 but past deficits have been managed thanks to substantial oil revenues and high domestic savings. However, the slow growth or decline of several traditional sources of revenue and the rising subsidy bill since 2007 have given pause for reflection on the traditional approach to fiscal management. In this paper, it is argued that fiscal management must not only centre around reducing non-productive expenditures and wasteful leakages but must also confront the problem of reducing and restructuring subsidies, particularly to petrol and petroleum-related products. The global dip in petroleum process has fortuitously provided the respite needed for such an exercise and should not lull policy makersinto complacency. When the economy recovers from the currentdownswing, a solid revenue raising instrument such as the value-addedtax must be introduced in order to wean the economy away from thecurrent over reliance on petroleum-based taxes.

  20. Air flow management in raised floor data centers

    CERN Document Server

    Arghode, Vaibhav K

    2016-01-01

    The Brief discuss primarily two aspects of air flow management in raised floor data centers. Firstly, cooling air delivery through perforated tiles will be examined and influence of the tile geometry on flow field development and hot air entrainment above perforated tiles will be discussed. Secondly, the use of cold aisle containment to physically separate hot and cold regions, and minimize hot and cold air mixing will be presented. Both experimental investigations and computational efforts are discussed and development of computational fluid dynamics (CFD) based models for simulating air flow in data centers is included. In addition, metrology tools for facility scale air velocity and temperature measurement, and air flow rate measurement through perforated floor tiles and server racks are examined and the authors present thermodynamics-based models to gauge the effectiveness and importance of air flow management schemes in data centers.

  1. Nuclear space power systems for orbit raising and maneuvering

    International Nuclear Information System (INIS)

    Buden, D.; Sullivan, J.A.

    1984-01-01

    Reference is made to recent studies which have shown that direct thrust nuclear rockets for routine orbit raising and near-earth space tug missions are probably not cost-effective. The need for additional trade-off studies and comparisons of direct-thrust nuclear systems with chemical systems to clarify the role of nuclear rockets in missions requiring rapid orbit maneuvering is stressed. Attention is confined here to nuclear electric propulsion considerations. Low-mass nuclear power plants are constructed to optimize nuclear electric propulsion systems. Electric power levels from 100 kilowatts to as much as several megawatts are desirable. The goals for the power plant specific mass are 20-30 kg/kW at the lower powers to 2-4 kg/kW at the higher powers

  2. Prospects of Foreign Capital Raising for Russian Power Grid Companies

    Directory of Open Access Journals (Sweden)

    N. N. Shvets

    2015-01-01

    Full Text Available The power sector reform in Russia saw capital raising as one of the key objectives. Additional investments are necessary, in particular, for renovation of fixed assets which are ca. 70% worn out. The official Strategy for the development of the Russian power grid also provides for privatization of certain companies and foreign investors are considered among others as the target audience. Upon prospective privatization the sector is expected not only to experience a certain increase in capital expenditures, but also to benefit from foreign expertise and efficiency enhancement. At the moment, however, the privatization plans are hard to implement due to a number of obstacles. Prospective investors are mostly concerned about the lack of transparent regulation and clear development strategy of the industry. This is particularly relevant to the tariff system, which has been continuously altered in recent years. This might be explained by the need of the state support by other sectors, which is often provided at the expense of the power industry. Furthermore, the prospects of foreign capital raising are negatively influenced by the conflict in Ukraine and the corresponding negative perception of potential investors. The above factors result in the decrease in value of power grid companies as well as in the lack of visibility regarding the prospects of the sector development. Privatization thus becomes unreasonable both for the state and prospective investors. At the same time, despite the sector specifics, there are precedents of successful sale of power grid assets to private investors by international peers. Particularly, Vatenfall and Forum have recently closed relevant transactions, nothing to say about the power grid sector of Brazil, majorly controlled by private owners. Transparent regulation, clear pricing rules and well-balanced economic policy are, indeed, indispensable prerequisites for successful privatization. Those might back up a

  3. Linking larval history to juvenile demography in the bicolor damselfish Stegastes partitus (Perciformes:Pomacentridae

    Directory of Open Access Journals (Sweden)

    Richard S Nemeth

    2005-05-01

    Full Text Available Otolith-based reconstructions of daily larval growth increments were used to examine the effect of variation in larval growth on size and age at settlement and post-settlement growth,survival and habitat preferences of juvenile bicolor damselfish (Stegastes partitus Poey.During August 1992 and 1994,newly settled S. partitus were collected from Montastraea coral heads and Porites rubble piles in Tague Bay,St.Croix,U.S. Virgin Islands (17 °45 ’ N,64 °42 ’ W.Daily lapillar otolith increments from each fish were counted and measured with Optimas image analysis software.S.partitus pelagic larval duration was 23.7 d in 1992 (n =70and 24.6 d in 1994 (n =38and larval age at settlement averaged 13.0 mm total length both years.Analysis of daily otolith increments demonstrated that variation in larval growth rates and size and age at settlement had no detectable effect on post-settlement survivorship but that larger larvae showed a preference for Montastraea coral at settlement.Late larval and early juvenile growth rates showed a significant positive relationship indicating that growth patterns established during the planktonic stage can span metamorphosis and continue into the benthic juvenile phase.Larval growth rates during the first two weeks post-hatching also had a strong effect on age to developmental competence (ability to undergo metamorphosisin both 1992 and 1994 with the fastest growing larvae being 8 d younger and 0.8 mm smaller at settlement than the slowest growing larvae.These differential growth rates in early stage larvae established trajectories toward larval developmental competence and may prove important in biogeographical studies of larval dispersal.Reconstruyendo aumentos diarios de otolitos se compará la variación en crecimiento larval sobre el tamaño y la edad de asentamiento,y el crecimiento post-acentamiento, sobrevivencia y preferencia de hábitat,del pez damisela bicolor (Stegastes partitus Poeyjoven.En agosto de 1992

  4. Descripción del último estadio larval de Neofulla biloba (Plecoptera: Notonemouridae Description of the last larval instar of Neofulla biloba (Plecoptera: Notonemouridae

    Directory of Open Access Journals (Sweden)

    Pablo Pessacq

    2008-12-01

    Full Text Available Se describe el último estadio larval de Neofulla biloba (Aubert, desconocido para la ciencia. Se brindan caracteres morfológicos que lo separan de N. areolata (Navás, la única especie del género cuya larva ha sido descripta previamente.The last instar larva of Neofulla biloba (Aubert is described for the first time. Morphological characters to separate it from that of N. areolata (Navás, the only previously known larva of the genus, are given.

  5. Intra-instar larval cannibalism in Anopheles gambiae (s.s.) and Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Porretta, Daniele; Mastrantonio, Valentina; Crasta, Graziano; Bellini, Romeo; Comandatore, Francesco; Rossi, Paolo; Favia, Guido; Bandi, Claudio; Urbanelli, Sandra

    2016-11-02

    Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1) has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4) of Anopheles gambiae (s.s.) and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size) on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s.) than in An. stephensi. In both species the total number of cannibalistic events increased from 0-24 to 0-48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s.) and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior and lower cannibalism rate. The understanding of

  6. Intra-instar larval cannibalism in Anopheles gambiae (s.s. and Anopheles stephensi (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Daniele Porretta

    2016-11-01

    Full Text Available Abstract Background Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1 has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4 of Anopheles gambiae (s.s. and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Results Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s. than in An. stephensi. In both species the total number of cannibalistic events increased from 0–24 to 0–48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. Conclusions The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s. and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior

  7. FAMILY CHIRONOMIDAE.

    Science.gov (United States)

    Mendes, Humberto Fonseca; Pinho, Luiz Carlos

    2016-06-14

    Only 30 chironomid species distributed in 16 genera and three subfamilies are formally recorded to Colombia. Another 32 genera and two subfamilies have been recorded on larval stage, with no identification at species level. Many new records, genera and species are expected when focusing on systematics of chironomids from Colombia.

  8. Identification of Gender-specific Transcripts by Microarray in Gonad Tissue of Larval and Juvenile Xenopus tropicalis

    Science.gov (United States)

    Amphibian model species Xenopus tropicalis is currently being utilized by EPA in the development of a standardized in vivo reproductive toxicity assay. Perturbations to the hypothalamic-pituitary-gonadal axis from exposure to endocrine disrupting compounds during larval develop...

  9. Molecular Techniques Revealed Highly Diverse Microbial Communities in Natural Marine Biofilms on Polystyrene Dishes for Invertebrate Larval Settlement

    KAUST Repository

    Lee, On On; Chung, Hong Chun; Yang, Jiangke; Wang, Yong; Dash, Swagatika; Wang, Hao; Qian, Pei-Yuan

    2014-01-01

    Biofilm microbial communities play an important role in the larval settlement response of marine invertebrates. However, the underlying mechanism has yet to be resolved, mainly because of the uncertainties in characterizing members

  10. Egg-larval mortality of Pacific herring in Prince William Sound, Alaska, after the Exxon Valdez oil spill

    International Nuclear Information System (INIS)

    McGurk, M. D.; Brown, E. D.

    1996-01-01

    Experiments were carried out to test the hypothesis that instantaneous daily rates of egg-larval mortality of Pacific herring were higher at two oil-exposed sites than at two other sites not so exposed. Results showed that egg-larval mortality was twice as great in the oil-exposed areas as in the two non-oiled areas. Larval growth rates were also severely affected; they were about half of those measured in populations from other areas of the north Pacific Ocean. A cautionary note was introduced to the effect that the differences in the egg-larval mortality between oiled and control sites may have been influenced by differences in egg dessication, predation, and wave scouring, hence these results should not be construed as conclusive evidence of oil spill damage. 40 refs., 6 figs

  11. The impact of food type, temperature and starvation on larval development of Balanus amphitrite Darwin (Cirripedia: Thoracica)

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, D.V.; Anil, A.C.

    The impact of diatom food species (Chaetoceros calcitrans and Skeletonema costatum), temperature and starvation on the larval development of Balanus amphitrite was evaluated. Starvation threshold levels for different ages of larvae (0- to 5-day...

  12. Variations in the drift of larval cod ( Gadus morhua L.) in the Baltic Sea : combining field observations and modelling

    DEFF Research Database (Denmark)

    Voss, R.; Hinrichsen, H.H.; St. John, Michael

    1999-01-01

    Coupled three-dimensional (3-D) physical oceanographic modelling and field sampling programmes were carried out in May 1988 and August 1991 to investigate the potential drift of larval cod (Gadus morhua L.) in the Bornholm Basin of the Baltic Sea. The goals were to predict the transport of cod...... larvae, thus aiding the identification of physical processes influencing larval retention/dispersal. Numerical simulations were performed using a 3-D eddy-resolving baroclinic model based on the Bryan-Cox-Semtner code adapted for the Baltic Sea. Within the Bornholm Basin, the model was initialized...... for the time periods considered. Larval drift was simulated either by incorporation of passive drifters, or as the initial horizontal distribution of larvae implemented into the model. Drift model simulations of larval transport agreed relatively well with field observations. The influence of variations...

  13. Role of emerald ash borer (Coleoptera: Buprestidae) larval vibrations in host-quality assessments by Tetrastichus planipennisi (Hymenoptera: Eulophidae)

    Science.gov (United States)

    Michael D. Ulyshen; Richard W. Mankin; Yigen Chen; Jian J. Duan; Therese M. Poland; Leah S. Bauer

    2011-01-01

    The biological control agent Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is a gregarious larval endoparasitoid of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive cambium-feeding species responsible for recent, widespread mortality of ash (Fraxinus spp.) in...

  14. Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

    KAUST Repository

    Abesamis, Rene A.; Saenz-Agudelo, Pablo; Berumen, Michael L.; Bode, Michael; Jadloc, Claro Renato L.; Solera, Leilani A.; Villanoy, Cesar L.; Bernardo, Lawrence Patrick C.; Alcala, Angel C.; Russ, Garry R.

    2017-01-01

    Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major

  15. Larval growth and drift pattern and the separation of herring spawning groups in the North Sea

    DEFF Research Database (Denmark)

    Munk, Peter; Christensen, Villy

    1990-01-01

    Data from two internationally co-ordinated survey programmes are used in an attempt to display the events in the early life that took place during the 'recovery period' of the North Sea herring stock, 1979-1986. During the period, an increasing importance of the spawning grounds off Buchan and off...... Yorkshire is evident from distributions of newly hatched herring larvae. The dramatic changes in relative importance of spawning grounds are traced in the data on both late larvae (6 months old) and juveniles (18 months old). The onset of extended spawning off Buchan and off Yorkshire was followed...... in the relative contributions from spawning grounds apparently influence the overall spatial distribution as well as size composition of larval and juvenile North Sea herring. The findings indicate that groups of larvae retain, to a large extent, separate distributions until metamorphosis, and point to larval...

  16. Larval ecomorphology of 13 Libellulidae (Anisoptera, Odonata of the Middle Rio Doce Valley, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    HC. Giacomini

    Full Text Available In the lakes of the Middle Rio Doce, Minas Gerais (MG, two groups of larval Libellulidae are distinguished by preferences of habitat use: one uses mainly aquatic macrophytes and the other uses the bottom substrate. The goal of this work was to verify if there is a morphological distinction between the two groups of species. Thirteen body measures were taken from the larvae and analyzed. No difference was found between the two groups of species regarding the body size, but shape differences were observed for two morphological variables. The species that use mainly macrophytes tend to have larger relative measures of the labium and smaller measures of the abdomen width. Advantages in resource obtainment and in vulnerability to predation are probably the explanations for the morphological divergence among these larval groups.

  17. Larval ecomorphology of 13 Libellulidae (Anisoptera, Odonata) of the Middle Rio Doce Valley, Minas Gerais, Brazil.

    Science.gov (United States)

    Giacomini, H C; De Marco, P

    2008-02-01

    In the lakes of the Middle Rio Doce, Minas Gerais (MG), two groups of larval Libellulidae are distinguished by preferences of habitat use: one uses mainly aquatic macrophytes and the other uses the bottom substrate. The goal of this work was to verify if there is a morphological distinction between the two groups of species. Thirteen body measures were taken from the larvae and analyzed. No difference was found between the two groups of species regarding the body size, but shape differences were observed for two morphological variables. The species that use mainly macrophytes tend to have larger relative measures of the labium and smaller measures of the abdomen width. Advantages in resource obtainment and in vulnerability to predation are probably the explanations for the morphological divergence among these larval groups.

  18. Larval fish collected from sound-scattering layers in an offshore tropical area.

    Science.gov (United States)

    Castro, M S; Bonecker, A C T

    2017-12-01

    The composition of the larval fish assemblage in the sound-scattering layer of the continental shelf waters off the coast of south-eastern Brazil (12 and 22° S), a research project that is part of the Brazilian programme Avaliação do Potencial Sustentável de Recursos Vivos na Zona Econômica Exclusiva (REVIZEE), is described. Samples were collected during daylight hours and at dusk at five oceanographic stations in the winter of 1999 using an Isaacs-Kidd Midwater Trawl (IKMT). The oceanographic stations were chosen based on the detection of plankton layers by acoustic observation. A total of 2192 larval fish were identified, comprising 52 families and 62 species. Maurolicus stehmanni (Sternoptychidae) was the most abundant species found within the study area, comprising 18·5% of all identified larvae, followed by Psilotris celsus (Gobiidae) at 10·9%. © 2017 The Fisheries Society of the British Isles.

  19. Recruitment decline in North Sea herring is accompanied by reduced larval growth rates

    DEFF Research Database (Denmark)

    Payne, Mark; Ross, Stine Dalmann; Worsøe Clausen, Lotte

    2013-01-01

    The stock of North Sea autumn spawning herring (Clupea harengus L.) has shown an unprecedented sequence of ten years of sharply reduced recruitment, in spite of a high spawning biomass. Recent work has identified this below-expected recruitment as being determined during the larval phase: however...... rate of 8%, concurrent with the reduced larval survival and recruitment, was identified: after correcting for the effect of other explanatory variables (e.g. temperature changes), the gross reduction was found to be 12%. This reduction is most probably due to changes in either the amount or quality...... and larvae survival, thereby narrowing the range of potential mechanisms underlying the observed reduction in the recruitment of North Sea autumn spawning herring...

  20. Phenoloxidase activity in larval and juvenile homogenates and adult plasma and haemocytes of bivalve molluscs.

    Science.gov (United States)

    Luna-González, Antonio; Maeda-Martínez, Alfonso N; Vargas-Albores, Francisco; Ascencio-Valle, Felipe; Robles-Mungaray, Miguel

    2003-10-01

    Phenoloxidase (PO) activity was studied in larval and juvenile homogenates and in the plasma and haemocytes of adult Crassostrea gigas, Argopecten ventricosus, Nodipecten subnodosus, and Atrina maura. Samples were tested for the presence of PO activity by incubation with the substrate L-3, 4-dihydroxyphenylalanine using trypsin, alpha-chymotrypsin, laminarin, lipopolysaccharides (LPS), and sodium dodecyl sulphate (SDS) to elicit activation of prophenoloxidase (proPO) system. PO activity was not detected in larval homogenate. In juvenile homogenate, PO activity was found only in C. gigas and N. subnodosus. PO activity was present in adult samples and was enhanced by elicitors in the plasma of all species tested, but in haemocyte lysate supernatant (HLS) of only N. subnodosus. Activation of proPO by laminarin was suppressed by a protease inhibitor cocktail (P-2714) in plasma and HLS of all species tested.

  1. Effect of Temperature on Feeding Period of Larval Blacklegged Ticks (Acari: Ixodidae) on Eastern Fence Lizards.

    Science.gov (United States)

    Rulison, Eric L; Lebrun, Roger A; Ginsberg, Howard S

    2014-11-01

    Ambient temperature can influence tick development time, and can potentially affect tick interactions with pathogens and with vertebrate hosts. We studied the effect of ambient temperature on duration of attachment of larval blacklegged ticks, Ixodes scapularis Say, to eastern fence lizards, Sceloporus undulatus (Bosc & Daudin). Feeding periods of larvae that attached to lizards under preferred temperature conditions for the lizards (WARM treatment: temperatures averaged 36.6°C at the top of the cage and 25.8°C at the bottom, allowing behavioral thermoregulation) were shorter than for larvae on lizards held under cool conditions (COOL treatment temperatures averaged 28.4°C at top of cage and 24.9°C at the bottom). The lizards were infested with larvae four times at roughly monthly intervals. Larval numbers successfully engorging and dropping declined and feeding period was longer after the first infestation. © 2014 Entomological Society of America.

  2. The effect of UV-C exposure on larval survival of the dreissenid quagga mussel

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri K.; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  3. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  4. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Directory of Open Access Journals (Sweden)

    Alecia Stewart-Malone

    Full Text Available The rapid spread of quagga mussels (Dreissena rostriformis bugensis has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  5. Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances

    DEFF Research Database (Denmark)

    Wollenberger, Leah; Breitholtz, M.; Kusk, Kresten Ole

    2003-01-01

    A nitro musk (musk ketone). and three polycyclic musks (Tonalide(TM), Galaxolide(TM) and Celestolide(TM)) were tested for acute and subchronic effects on a marine crustacean, the calanoid copepod Acartia tonsa. Sublethal effects on A. tonsa larvae were investigated with a rapid and cost effective...... bioassay, which is based on the easily detectable morphological change from the last nauplius to the first copepodite stage during copepod larval development. The inhibition of larval development after 5 days exposure was a very sensitive endpoint, with 5-d-EC(50)-values as low as 0.026 mg/l (Tonalide...... of synthetic musks, for which there is little published ecotoxicological information available regarding Crustacea. It is suggested that subchronic and chronic copepod toxicity tests should be used more frequently for risk assessment of environmental pollutants. (C) 2002 Elsevier Science B.V. All rights...

  6. The complete larval development of the mud shrimp Upogebia vasquezi (Gebiidea: Upogebiidae) reared in the laboratory.

    Science.gov (United States)

    De Oliveira, Danielly Brito; Martinelli-Lemos, Jussara Moretto; Abrunhosa, Fernando Araújo

    2014-07-01

    The larval development of Upogebia vasquezi consists of four zoeal stages and a megalopa. In the present study, each larval stage was described and illustrated in detail. The first two stages are re-described in order to provide a detailed comparison with the data available for this species recorded in a previous study. The morphological features of all the stages are compared with those of the larvae of other Upogebia species reported previously in the literature. Broad morphological similarities and distinctions were found among most Upogebia species. The main interspecific variations in the morphology of the zoeal stages are the segmentation pattern of the antennular endopod and number of aesthetascs, the number of setae on the scaphognathite and the presence or absence of a mandibular palp.

  7. Effects of mercury on survival and development of the larval grass shrimp Palaemonetes vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Shealy, M.H. Jr.; Sandifer, P.A.

    1975-11-10

    Effects of 7 concentrations of mercury from 0.0 (control) to 0.056 ppM on survival and development of the larval grass shrimp Palaemonetes vulgaris (Say) were investigated. A concentration of 0.056 ppM Hg was toxic to all larvae within 24 h, but below a threshold level (less than or equal to 0.0056 ppM) no lethal effect occurred within 48 h. Feeding appeared to increase slightly the resistance of P. vulgaris larvae to mercury, and 48-h median tolerance limits for fed and unfed larvae were 0.0156 and 0.0100 ppM, respectively. Delayed effects of 48-h exposure to sublethal mercury concentrations which appeared in later post-exposure rearing of the larvae included reduced survival to the postlarval stage, delayed molting, extended development time, increased numbers of larval instars, and morphological deformities.

  8. Larval development and shape variation of the kelpfish Myxodes viridis (Teleostei: Clinidae

    Directory of Open Access Journals (Sweden)

    Francisca Zavala-Muñoz

    2016-03-01

    Full Text Available Larval development and shape ontogeny of the kelpfish Myxodes viridis (Clinidae are described for the first time. A total of 214 individuals ranging between 3.51 and 23.09 mm standard length collected off central Chile were assessed employing classic and geometric morphometrics, illustration with camera lucida and a double-staining technique for cartilaginous and bone structure observation. Based on characteristics such as yolk sac presence and fin formation, six stages of larval development were differentiated: yolk sac, preflexion, flexion, early postflexion, late postflexion and juvenile. Shape changes during development are subtle and occur smoothly, being more significant in the head and preanal length, and ontogenetic allometry accounts for almost 15%. Cartilage formation takes place first at the branchial arches and cranium; then hypural, haemal and neural arches are consecutively formed. Bony structure ossification occurs late in the development. Vertebral centra ossify directly, without cartilaginous matrix replacement.

  9. Drivers of larval fish assemblage shift during the spring-summer transition in the coastal Mediterranean

    Science.gov (United States)

    Álvarez, Itziar; Catalán, Ignacio A.; Jordi, Antoni; Palmer, Miquel; Sabatés, Ana; Basterretxea, Gotzon

    2012-01-01

    The influence of coastal environmental conditions from winter-spring to summer on fish larvae assemblages in a temperate area has suggested a seasonal shift in ecosystem-level variation through which trophic pathways shift from the pelagic to the benthic system. This variation may be related to marked effects in the reproductive strategies in the fishes inhabiting the area and indirectly affect ichthyoplankton assemblages. Larval fish assemblages were sampled fortnightly at three stations located in coastal waters off southern Mallorca (Western Mediterranean) from March to August 2007, covering the main spawning period for the resident coastal fish in this region. The larval fish assemblage showed clear seasonality with higher specific abundance but lower diversity in the spring. Two main assemblages were identified: a spring assemblage, occurring at surface seawater temperatures ichthyoplankton communities occurred in early June, coinciding with the onset of summer hydrographical conditions and the local benthic productivity peak.

  10. Gamma irradiation effects on larval and pupal stages on the saw toothed grain beetle oryzaephilus

    International Nuclear Information System (INIS)

    Younes, M.W.; Ahmed, M.Y.Y.

    1978-01-01

    Effects of gamma irradiation from Co 60 on larval and pupal stages of the saw-toothed grain beetle. Oryzaephilus surinamensis L. were determined. Larval and pupal sensitivity depended on age at treatment, the older the larvae or pupae, the less susceptible. No adults emerged in the 10- to 12-day larvae and 4-day old pupae when irradiated at 10 and 100 Krad. respectively. Irradiation of larvae and pupae especially at high doses, resulted in reduced percent adult emergence in incomplete emergence, and in structural deformities. The percentage sterility for both sexes at each dosage used were determined. Males and females irradiated asl-d and 4-d-old pupae, then mated with normal unmated adults of the opposite sex laid infertile eggs when irradiated at 12 Krad. Adult mortality from irradiated pupae (1- or 4-d-old) was increased with the increase of the dose

  11. Food of larval Anopheles culicifacies and Anopheles varuna in a stream habitat in Sri Lanka

    DEFF Research Database (Denmark)

    Piyaratne, M K; Amerasinghe, P H; Amerasinghe, F P

    2005-01-01

    -phenylindole, was used to stain larval gut contents. Quantitative estimates of different categories of food types were made by analyzing the gut contents of 95 An. culicifacies (26 second instars and 69 fourth instars) and 52 An. varuna (21 second instars and 31 fourth instars). Detritus was the most frequent......No previous studies have been conducted on the natural food of larval Anopheles culicifacies s.l. (the major malaria vector) and An. varuna (a secondary vector) in Sri Lanka. The present study analyzed the contents of guts dissected from larvae collected from pools in a natural stream...... food type, comprising >74% of the gut contents in both species. Other food types included bacteria (cocci and rods), filamentous algae, diatoms, and desmids. Overall, bacteria constituted a significantly higher proportion of the gut contents in An. culicifacies than in An varuna. Significantly more...

  12. Larval development of hoplias cf. Lacerdae (Pisces: Erythrinidae and delayed initial feeding effects

    Directory of Open Access Journals (Sweden)

    Rodolfo N. Sirol

    1998-06-01

    Full Text Available Larval development of Hoplias cf. lacerdae was studied under laboratory conditions. After hatching, ontogenetic changes were recorded on food-deprived larvae in 12-hour intervals. Mouth opening occurred after 2.5 days and notochord terminated flexure in 6.5 days. Notochord length increased at a constant rate until complete yolk absorption (13,5 days. Larval dry weight and body height diminished gradually up to 21 days after hatching, when all starved larvae died. Every 12 hours after yolk absorption, groups of larvae (n=15, were separeted, and fed with Artemia nauplii for 10 days. The point-of-no-return (when 50% of larvae were unable to feed or to assimilate ingested food after delayed feeding, was not apparent in this species.

  13. Global mismatch between fishing dependency and larval supply from marine reserves

    Science.gov (United States)

    Andrello, Marco; Guilhaumon, François; Albouy, Camille; Parravicini, Valeriano; Scholtens, Joeri; Verley, Philippe; Barange, Manuel; Sumaila, U. Rashid; Manel, Stéphanie; Mouillot, David

    2017-07-01

    Marine reserves are viewed as flagship tools to protect exploited species and to contribute to the effective management of coastal fisheries. Yet, the extent to which marine reserves are globally interconnected and able to effectively seed areas, where fisheries are most critical for food and livelihood security is largely unknown. Using a hydrodynamic model of larval dispersal, we predict that most marine reserves are not interconnected by currents and that their potential benefits to fishing areas are presently limited, since countries with high dependency on coastal fisheries receive very little larval supply from marine reserves. This global mismatch could be reversed, however, by placing new marine reserves in areas sufficiently remote to minimize social and economic costs but sufficiently connected through sea currents to seed the most exploited fisheries and endangered ecosystems.

  14. New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory

    Directory of Open Access Journals (Sweden)

    Cherre Sade Bezerra Da Silva

    2013-09-01

    Full Text Available New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory. Here we show, for the first time, that larvae of the fall armyworm (FAW, Spodoptera frugiperda (Lepidoptera, Noctuidae, can be successfully reared in a cohort-based manner with virtually no cannibalism. FAW larvae were reared since the second instar to pupation in rectangular plastic containers containing 40 individuals with a surprisingly ca. 90% larval survivorship. Adult females from the cohort-based method showed fecundity similar to that already reported on literature for larvae reared individually, and fertility higher than 99%, with the advantage of combining economy of time, space and material resources. These findings suggest that the factors affecting cannibalism of FAW larvae in laboratory rearings need to be reevaluated, whilst the new technique also show potential to increase the efficiency of both small and mass FAW rearings.

  15. Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields

    DEFF Research Database (Denmark)

    Mutero, C M; Ng'ang'a, P N; Wekoyela, P

    2004-01-01

    Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block, and the fertili......Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block...... populations of An. arabiensis (Pmosquitoes (P... in rice fields, thereby making them visually more attractive for egg-laying by An. arabiensis and culicine mosquitoes....

  16. larvalign: Aligning Gene Expression Patterns from the Larval Brain of Drosophila melanogaster.

    Science.gov (United States)

    Muenzing, Sascha E A; Strauch, Martin; Truman, James W; Bühler, Katja; Thum, Andreas S; Merhof, Dorit

    2018-01-01

    The larval brain of the fruit fly Drosophila melanogaster is a small, tractable model system for neuroscience. Genes for fluorescent marker proteins can be expressed in defined, spatially restricted neuron populations. Here, we introduce the methods for 1) generating a standard template of the larval central nervous system (CNS), 2) spatial mapping of expression patterns from different larvae into a reference space defined by the standard template. We provide a manually annotated gold standard that serves for evaluation of the registration framework involved in template generation and mapping. A method for registration quality assessment enables the automatic detection of registration errors, and a semi-automatic registration method allows one to correct registrations, which is a prerequisite for a high-quality, curated database of expression patterns. All computational methods are available within the larvalign software package: https://github.com/larvalign/larvalign/releases/tag/v1.0.

  17. Nutritional enrichment of larval fish feed with thraustochytrid producing polyunsaturated fatty acids and xanthophylls.

    Science.gov (United States)

    Yamasaki, Takashi; Aki, Tsunehiro; Mori, Yuhsuke; Yamamoto, Takeki; Shinozaki, Masami; Kawamoto, Seiji; Ono, Kazuhisa

    2007-09-01

    In marine aquaculture, rotifers and Artemia nauplii employed as larval fish feed are often nutritionally enriched with forage such as yeast and algal cells supplemented with polyunsaturated fatty acids and xanthophylls, which are required for normal growth and a high survival ratio of fish larvae. To reduce the enrichment steps, we propose here the use of a marine thraustochytrid strain, Schizochytrium sp. KH105, producing docosahexaenoic acid, docosapentaenoic acid, canthaxanthin, and astaxanthin. The KH105 cells prepared by cultivation under optimized conditions were successfully incorporated by rotifers and Artemia nauplii. The contents of docosahexaenoic acid surpassed the levels required in feed for fish larvae, and the enriched Artemia showed an increased body length. The results demonstrate that we have developed an improved method of increasing the dietary value of larval fish feed.

  18. Raising the acceptance of the AP2-line

    International Nuclear Information System (INIS)

    Trbojevic, D.

    1989-01-01

    The 120 GeV Main Ring proton beam collides with the target at the end of the AP-1 line and creates antiprotons and other secondary particles. The AP-2 line transfers the negative particles from the target to the Debuncher. To provide a bigger antiproton stack size in the Accumulator, both the Debuncher as well as the AP-2 line acceptance have to be raised. This is a proposal for the improvement of the AP-2 line acceptance. The first part of the memo presents an acceptance examination of the existing AP-2 line by computer simulation, while the second presents a short proposal for aperture corrections. The computer program TURTLE was used to trace antiprotons through the AP-2 line without taking into account other negative charged particles. Betatron functions were obtained from the output of the SYNCH computer program. The SYNCH program was also used to check the dispersion match between the AP-2 line and the Debuncher. 3 refs., 6 figs., 5 tabs

  19. Raising environmental awareness through applied biochemistry laboratory experiments.

    Science.gov (United States)

    Salman Ashraf, S

    2013-01-01

    Our environment is under constant pressure and threat from various sources of pollution. Science students, in particular chemistry students, must not only be made aware of these issues, but also be taught that chemistry (and science) can provide solutions to such real-life issues. To this end, a newly developed biochemistry laboratory experiment is described that guides students to learn about the applicability of peroxidase enzymes to degrade organic dyes (as model pollutants) in simulated waste water. In addition to showing how enzymes can potentially be used for waste water remediation, various factors than can affect enzyme-based reactions such as pH, temperature, concentration of substrates/enzymes, and denaturants can also be tested. This "applied biotechnology" experiment was successfully implemented in an undergraduate biochemistry laboratory course to enhance students' learning of environmental issues as well important biochemistry concepts. Student survey confirmed that this laboratory experiment was successful in achieving the objectives of raising environmental awareness in students and illustrating the usefulness of chemistry in solving real-life problems. This experiment can be easily adopted in an introductory biochemistry laboratory course and taught as an inquiry-guided exercise. © 2013 by The International Union of Biochemistry and Molecular Biology.

  20. [Multiple pregnancies prevalence: its raise on last decade].

    Science.gov (United States)

    Herrera, Ricardo Jorge Hernández; Torres, Mauro Ochoa; Santos, Roberto Flores; Flores, Raúl Cortés; Sánchez, Gerardo Forsbasch

    2008-09-01

    Multiple pregnancies prevalence has been increasing in last decade, which have also increased the requirements of neonatal intensive care units and all problems related to premature neonate or low birth weight. Prevalence rate of twin (18 to 26 in 1,000 births), and triple pregnancies (0.37 to 1.74 in 1,000 births) have raised too, perhaps due to assisted reproductive techniques. To know incidence of multiple pregnancies at Unidad Medica de Alta Especialidad no. 23, from Institute Mexicano del Seguro Social. Retrospective and descriptive study. We review the files of multiple pregnancies from 1972 to 2006 to estimate its rate and change every five and ten years. We registered 9,055 twin pregnancies during the period, with a rate of 7.1 to 14.4 in 1,000 (63% of increase in the last decade [12.6 in 1,000 births] compared with the previous decade [7.7 in 1,000 births]; p < 0.005). Pregnancies with three or more fetuses were 202, with 191 triplets, 13 with four, three with five, and one with six products (646 newborns). Incidence of multiple pregnancies with four or more products has also increased in last decade: 230 times higher than two decades before. Multiple pregnancies rate has increased in last decade: 63% in twin pregnancies, 217% in triplets, and 230 times more than expected in four or more products pregnancies.

  1. Latino Solo Grandparents Raising Grandchildren: Health Risks and Behaviors.

    Science.gov (United States)

    Whitley, Deborah M; Fuller-Thomson, Esme

    2018-03-01

    The purpose of this descriptive report is to provide the first representative information on the sociodemographic profile and the prevalence of mental and physical health conditions of two "at-risk" groups of Latino caregivers: solo grandparent caregivers and single parents. The 2012 Behavior Risk Factor Surveillance System was used to compare five dimensions of health on a sample of Latino solo grandparents and Latino single parents, raising their grandchildren/children alone. Bivariate and logistic regression comparative analyses were conducted on study measures. Latino solo grandparents have a high prevalence of chronic health conditions, including arthritis (51%), depression (40%), diabetes (34%), and asthma (34%). Latino single parents have lower but troubling health risks, including depression (22%), diabetes (14%), and asthma (14%). Differences between the two groups were largely due to the grandparents older age. Latino solo grandparents have a high prevalence of several chronic medical conditions. The prevalence of disorders is much lower for Latino single parents, although they too have disturbing health risks. Latino solo grandparents perform their parenting role under intense physical and emotional strain. Health professionals can be instrumental in facilitating interventions that affect the well-being of this expanding family group.

  2. Motor neurone disease presenting with raised serum Troponin T.

    Science.gov (United States)

    Mamo, Jonathan P

    2015-05-01

    Myocardial damage indicated by a rise in cardiac Troponin may not necessarily be due to a cardiac event. Many diseases such as sepsis, pulmonary embolism, heart and renal failure can also be associated with an elevated cardiac Troponin level. This brief report discusses the rare event of a patient with motor neurone disease, where the possible diagnosis of acute myocardial infarction arose due to an elevated cardiac Troponin. A 69-year-old gentleman presented with a history of a central chest ache of mild intensity, lasting a total of 2 h prior to complete resolution. Multiple cardiac Troponin assays were elevated, and echocardiography did not show any acute changes of myocardial damage. His electrocardiogram was also normal. This patient's raised cardiac Troponin was therefore explained on the basis of his active motor neurone disease. This rare case outlines the importance of considering motor neurone disease as a cause of elevated cardiac Troponin in the absence of clinical evidence of an acute coronary event. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  3. Parental Stress in Raising a Child with Disabilities in India

    Directory of Open Access Journals (Sweden)

    Naveen Mehrotra

    2012-08-01

    Full Text Available  Purpose: To determine the parenting stress and its determinants among parents of children with disabling conditions in India.Methods: The Parenting Stress Index – short form and a few open ended questions were administered to a convenience sample of sixty-six patient families in July, 2009 in the cities of New Delhi and Faridabad regions of Northern India through six non- governmental organizations (NGOs that serve children with disabling conditions. Results: Female sex of the child was associated with higher stress related to failure of the child to meet parent’s expectations and to satisfy the parents in their parenting role. Parents engaged in more lucrative and prestigious occupations had more stress than parents engaged in less prestigious and lucrative occupations irrespective of their income. Many parents reported receiving little support from their extended families in taking care of their child. Religion was found to be a common coping resource used by the parents.Conclusion and Implications: Higher parenting stress in parents of girls raises the possibility of abuse and neglect. Little support from informal family resources underscores the need for developing formal resources for supporting the parents. The specific resources of parenting stress among parents of different socioeconomic status should be explored in future studies so that appropriate interventions can be planned.doi 10.5463/DCID.v23i2.119

  4. Implications of raising cigarette excise taxes in Peru

    Directory of Open Access Journals (Sweden)

    Martin Gonzalez-Rozada

    Full Text Available ABSTRACT Objective To assess how raising cigarette excise taxes in Peru might impact cigarette consumption, and to determine if higher taxes would be regressive. Methods Total demand price elasticity was estimated by income groups using two datasets: quarterly time-series data from 1993 – 2012 and data from a cross-sectional survey of income and expenses conducted in 2008 – 2009 . A functional form of the cigarette demand in Peru was specified using the quarterly data set, and the demand price elasticity was estimated for the short and long run. Using the second data set and Deaton methodology, the implementation of elasticity estimation and by groups’ elasticity was done in a two-step procedure. Results Demand price elasticity was −0.7, implying that a 10% price increase via a new tax would reduce consumption by 7%. Demand price elasticity estimations by income group suggested that poorer families are not more price sensitive than richer ones, which implies that increasing cigarette taxes could be regressive. Conclusions Increasing cigarette taxes is the most efficient policy for inducing a reduction in smoking. However, in the case of Peru, an increase in cigarette taxes could be regressive.

  5. Paternity of subordinates raises cooperative effort in cichlids.

    Directory of Open Access Journals (Sweden)

    Rick Bruintjes

    Full Text Available In cooperative breeders, subordinates generally help a dominant breeding pair to raise offspring. Parentage studies have shown that in several species subordinates can participate in reproduction. This suggests an important role of direct fitness benefits for cooperation, particularly where groups contain unrelated subordinates. In this situation parentage should influence levels of cooperation. Here we combine parentage analyses and detailed behavioural observations in the field to study whether in the highly social cichlid Neolamprologus pulcher subordinates participate in reproduction and if so, whether and how this affects their cooperative care, controlling for the effect of kinship.We show that: (i male subordinates gained paternity in 27.8% of all clutches and (ii if they participated in reproduction, they sired on average 11.8% of young. Subordinate males sharing in reproduction showed more defence against experimentally presented egg predators compared to subordinates not participating in reproduction, and they tended to stay closer to the breeding shelter. No effects of relatedness between subordinates and dominants (to mid-parent, dominant female or dominant male were detected on parentage and on helping behaviour.This is the first evidence in a cooperatively breeding fish species that the helping effort of male subordinates may depend on obtained paternity, which stresses the need to consider direct fitness benefits in evolutionary studies of helping behaviour.

  6. Raised Vaginal Fluid Fibronectin Level Indicates Premature Rupture of Membrane

    Directory of Open Access Journals (Sweden)

    Amrita Bhowmik

    2012-07-01

    Full Text Available Background: Premature rupture of membrane (PROM is one of the common complications of pregnancy that has major impact on fetal and neonatal outcome. It is the commonest clinical event where a normal pregnancy becomes suddenly a high-risk one for mother and fetus or neonate. Objective: The study was undertaken to investigate whether raised fibronectin level in vaginal fluid may indicate premature rupture of membrane. Materials and Methods: This cross sectional study was conducted in the department of Obstetrics and Gynecology in Sir Salimullah Medical College & Mitford Hospital, Dhaka during the period of January 2006 to December 2007. A total of 114 pregnant women with gestational age 28th week up to 40th week were included. Sixty were PROM (Group I and 54 were non-PROM (Group II subjects. Fibronectin in vaginal fluid was measured by an immunochemical reaction by nephelometer. Statistical analysis was done by SPSS version 10.0. Results: The PROM patients had significantly higher concentration of fibronectin (225.77 ± 115.18 ng/mL compared to that in non-PROM subjects (8.04 ± 16.17 ng/mL (p < 0.001. Conclusion: It can be concluded that in cases of unequivocal rupture or intactness of the membranes, the result of the fibronectin test corresponds well with the clinical situation. So fibronectin is a sensitive test for detection of amniotic fluid in the vagina.

  7. Toward raising the higher level of radiological nursing

    International Nuclear Information System (INIS)

    Kusama, Tomoko; Ban, Nobuhiko; Ono, Koji

    2013-01-01

    The role and purpose of nursing in the radiological field are discussed with essentials of radiological nursing for raising its higher level and needed fundamental education. The discussion is from the thought that, at Fukushima Nuclear Power Plant Accident (Mar. 2011), general medical staff including nurses are rather insufficient of radiological knowledge like the exposure, radiation effect and risk. In the medical radiological field, nurses are expected to play roles of arranging the circumstance for patient's ease like explanation about health effect/risk, appropriate nursing of them after radiological diagnosis, radiation protection of nurses themselves, and of environment. At such an emergency as the Accident, care for the acutely exposed victims, their decontamination and responding to patient's concern are necessary. At the later phase, also needed are nursing of victims undergoing health management done by authorities and of radiological workers concerned as well as the third item above. Therefore, fundamentals of radiological knowledge such as physics, exposure, health effects, protection, contamination, legal rules and risk communication are required in the education of nurses. Otherwise, this education can be conducted as a part of safety security and physical assessment. The Accident also gives us the importance of radiological risk communication with its victims. (T.T.)

  8. Combined Effects of Temperature and Salinity on Larval Development of the Mangrove Crab Parasesarma catenata Ortman, 1897 (Brachyura: Sesarmidae)

    OpenAIRE

    Mwaluma, J.; Nogueira Mendes, R.; Raedig, C.; Emmerson, W.; Paula, J.

    2003-01-01

    The larval stages of the mangrove crab Parasesarma catenata were reared in the laboratory from eggs of females collected in the Mgazana estuary, South Africa. Survival and duration of larval stages were tested for the combined effects of temperature and salinity in a factorial design experiment, using three females each with two replicates of 15 larvae per combination. Combinations were made from five temperature (15, 20, 25, 30 and 35 ºC) and four salinity values (15, 25, 35 a...

  9. Longfin yellowtail (SEriola rivoliana) larval rearing: skeletal development and effects of increasing dietary DHA levels at weaning phase

    OpenAIRE

    Mesa-Rodríguez, Antonio

    2017-01-01

    Programa de doctorado: Acuicultura: producción controlada de animales acuáticos [EN] Seriola rivoliana is considered as relevant species for aquaculture diversification and the information available is limited. The main objective of the present Thesis was to improve longfin yellowtail (S. rivoliana) larval production. In this sense, three specific objectives were established, in order to evaluate the most appropriate larval rearing technique, the obtention of bone development information a...

  10. Large-scale, multidirectional larval connectivity among coral reef fish populations in the Great Barrier Reef Marine Park

    KAUST Repository

    Williamson, David H.

    2016-11-15

    Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no-take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40 km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60–220 km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P. maculatus and 17 juvenile P. leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short-distance larval dispersal within regions (200 m to 50 km) and long-distance, multidirectional dispersal of up to ~250 km among regions. Dispersal strength declined significantly with distance, with best-fit dispersal kernels estimating median dispersal distances of ~110 km for P. maculatus and ~190 km for P. leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long-distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.

  11. Environmental calcium and variation in yolk sac size influence swimming performance in larval lake sturgeon (Acipenser fulvescens)

    DEFF Research Database (Denmark)

    Deslauriers, David; Svendsen, Jon Christian; Genz, Janet

    2018-01-01

    , because the yolk sac is likely to affect drag forces during swimming. Testing swimming performance of larval A. fulvescens reared in four different calcium treatments spanning the range of 4-132 mg l-1 [Ca2+], this study found no treatment effects on the sprint swimming speed. A novel test of volitional...... reduced swimming performance and could be more susceptible to predation or premature downstream drift. Our study reveals how environmental factors and phenotypic variation influence locomotor performance in a larval fish....

  12. Larval dispersal modeling of pearl oyster Pinctada margaritifera following realistic environmental and biological forcing in Ahe atoll lagoon.

    Directory of Open Access Journals (Sweden)

    Yoann Thomas

    Full Text Available Studying the larval dispersal of bottom-dwelling species is necessary to understand their population dynamics and optimize their management. The black-lip pearl oyster (Pinctada margaritifera is cultured extensively to produce black pearls, especially in French Polynesia's atoll lagoons. This aquaculture relies on spat collection, a process that can be optimized by understanding which factors influence larval dispersal. Here, we investigate the sensitivity of P. margaritifera larval dispersal kernel to both physical and biological factors in the lagoon of Ahe atoll. Specifically, using a validated 3D larval dispersal model, the variability of lagoon-scale connectivity is investigated against wind forcing, depth and location of larval release, destination location, vertical swimming behavior and pelagic larval duration (PLD factors. The potential connectivity was spatially weighted according to both the natural and cultivated broodstock densities to provide a realistic view of connectivity. We found that the mean pattern of potential connectivity was driven by the southwest and northeast main barotropic circulation structures, with high retention levels in both. Destination locations, spawning sites and PLD were the main drivers of potential connectivity, explaining respectively 26%, 59% and 5% of the variance. Differences between potential and realistic connectivity showed the significant contribution of the pearl oyster broodstock location to its own dynamics. Realistic connectivity showed larger larval supply in the western destination locations, which are preferentially used by farmers for spat collection. In addition, larval supply in the same sectors was enhanced during summer wind conditions. These results provide new cues to understanding the dynamics of bottom-dwelling populations in atoll lagoons, and show how to take advantage of numerical models for pearl oyster management.

  13. Large-scale, multidirectional larval connectivity among coral reef fish populations in the Great Barrier Reef Marine Park

    KAUST Repository

    Williamson, David H.; Harrison, Hugo B.; Almany, Glenn R.; Berumen, Michael L.; Bode, Michael; Bonin, Mary C.; Choukroun, Severine; Doherty, Peter J.; Frisch, Ashley J.; Saenz-Agudelo, Pablo; Jones, Geoffrey P.

    2016-01-01

    Larval dispersal is the key process by which populations of most marine fishes and invertebrates are connected and replenished. Advances in larval tagging and genetics have enhanced our capacity to track larval dispersal, assess scales of population connectivity, and quantify larval exchange among no-take marine reserves and fished areas. Recent studies have found that reserves can be a significant source of recruits for populations up to 40 km away, but the scale and direction of larval connectivity across larger seascapes remain unknown. Here, we apply genetic parentage analysis to investigate larval dispersal patterns for two exploited coral reef groupers (Plectropomus maculatus and Plectropomus leopardus) within and among three clusters of reefs separated by 60–220 km within the Great Barrier Reef Marine Park, Australia. A total of 69 juvenile P. maculatus and 17 juvenile P. leopardus (representing 6% and 9% of the total juveniles sampled, respectively) were genetically assigned to parent individuals on reefs within the study area. We identified both short-distance larval dispersal within regions (200 m to 50 km) and long-distance, multidirectional dispersal of up to ~250 km among regions. Dispersal strength declined significantly with distance, with best-fit dispersal kernels estimating median dispersal distances of ~110 km for P. maculatus and ~190 km for P. leopardus. Larval exchange among reefs demonstrates that established reserves form a highly connected network and contribute larvae for the replenishment of fished reefs at multiple spatial scales. Our findings highlight the potential for long-distance dispersal in an important group of reef fishes, and provide further evidence that effectively protected reserves can yield recruitment and sustainability benefits for exploited fish populations.

  14. Whole-genome sequence of Clostridium lituseburense L74, isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus

    OpenAIRE

    Lee, Yookyung; Lim, Sooyeon; Rhee, Moon-Soo; Chang, Dong-Ho; Kim, Byoung-Chan

    2016-01-01

    Clostridium lituseburense L74 was isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus collected in Yeong-dong, Chuncheongbuk-do, South Korea and subjected to whole genome sequencing on HiSeq platform and annotated on RAST. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession NZ_LITJ00000000. Keywords: Insect, Larval gut, Whole genome shot-gun sequencing

  15. Whole-genome sequence of Clostridium lituseburense L74, isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus

    Directory of Open Access Journals (Sweden)

    Yookyung Lee

    2016-03-01

    Full Text Available Clostridium lituseburense L74 was isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus collected in Yeong-dong, Chuncheongbuk-do, South Korea and subjected to whole genome sequencing on HiSeq platform and annotated on RAST. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession NZ_LITJ00000000. Keywords: Insect, Larval gut, Whole genome shot-gun sequencing

  16. Induction of larval metamorphosis of the coral Acropora millepora by tetrabromopyrrole isolated from a Pseudoalteromonas bacterium.

    Directory of Open Access Journals (Sweden)

    Jan Tebben

    Full Text Available The induction of larval attachment and metamorphosis of benthic marine invertebrates is widely considered to rely on habitat specific cues. While microbial biofilms on marine hard substrates have received considerable attention as specific signals for a wide and phylogenetically diverse array of marine invertebrates, the presumed chemical settlement signals produced by the bacteria have to date not been characterized. Here we isolated and fully characterized the first chemical signal from bacteria that induced larval metamorphosis of acroporid coral larvae (Acropora millepora. The metamorphic cue was identified as tetrabromopyrrole (TBP in four bacterial Pseudoalteromonas strains among a culture library of 225 isolates obtained from the crustose coralline algae Neogoniolithon fosliei and Hydrolithon onkodes. Coral planulae transformed into fully developed polyps within 6 h, but only a small proportion of these polyps attached to the substratum. The biofilm cell density of the four bacterial strains had no influence on the ratio of attached vs. non-attached polyps. Larval bioassays with ethanolic extracts of the bacterial isolates, as well as synthetic TBP resulted in consistent responses of coral planulae to various doses of TBP. The lowest bacterial density of one of the Pseudoalteromonas strains which induced metamorphosis was 7,000 cells mm(-2 in laboratory assays, which is on the order of 0.1-1% of the total numbers of bacteria typically found on such surfaces. These results, in which an actual cue from bacteria has been characterized for the first time, contribute significantly towards understanding the complex process of acroporid coral larval settlement mediated through epibiotic microbial biofilms on crustose coralline algae.

  17. Larval spirurida (Nematoda) from the crab Macrophthalmus hirtipes in New Zealand

    DEFF Research Database (Denmark)

    Moravec, Frantisek; Fredensborg, Brian Lund; Latham, A David M

    2003-01-01

    to a species of Ascarophis van Beneden, 1871 (Cystidicolidae), the genus including parasites of fishes, whereas the smaller larvae (about 4-5 mm long) belonged to the Acuariidae, a family with species parasitic as adults mostly in aquatic birds. In a sample of 82 specimens of M. hirtipes collected in July 2002....... Apparently, crabs play a role as intermediate hosts of these nematode species. This is the first record of larval representatives of Cystidicolidae and Acuariidae from invertebrates in the Australasian Region....

  18. Pelagic larval duration predicts extinction risk in a freshwater fish clade

    OpenAIRE

    Douglas, Morgan; Keck, Benjamin P.; Ruble, Crystal; Petty, Melissa; Shute, J. R.; Rakes, Patrick; Hulsey, C. Darrin

    2013-01-01

    Pelagic larval duration (PLD) can influence evolutionary processes ranging from dispersal to extinction in aquatic organisms. Using estimates of PLD obtained from species of North American darters (Percidae: Etheostomatinae), we demonstrate that this freshwater fish clade exhibits surprising variation in PLD. Comparative analyses provide some evidence that higher stream gradients favour the evolution of shorter PLD. Additionally, similar to patterns in the marine fossil record in which lower ...

  19. Landscape determinants and remote sensing of anopheline mosquito larval habitats in the western Kenya highlands.

    Science.gov (United States)

    Mushinzimana, Emmanuel; Munga, Stephen; Minakawa, Noboru; Li, Li; Feng, Chen-Chieng; Bian, Ling; Kitron, Uriel; Schmidt, Cindy; Beck, Louisa; Zhou, Guofa; Githeko, Andrew K; Yan, Guiyun

    2006-02-16

    In the past two decades the east African highlands have experienced several major malaria epidemics. Currently there is a renewed interest in exploring the possibility of anopheline larval control through environmental management or larvicide as an additional means of reducing malaria transmission in Africa. This study examined the landscape determinants of anopheline mosquito larval habitats and usefulness of remote sensing in identifying these habitats in western Kenya highlands. Panchromatic aerial photos, Ikonos and Landsat Thematic Mapper 7 satellite images were acquired for a study area in Kakamega, western Kenya. Supervised classification of land-use and land-cover and visual identification of aquatic habitats were conducted. Ground survey of all aquatic habitats was conducted in the dry and rainy seasons in 2003. All habitats positive for anopheline larvae were identified. The retrieved data from the remote sensors were compared to the ground results on aquatic habitats and land-use. The probability of finding aquatic habitats and habitats with Anopheles larvae were modelled based on the digital elevation model and land-use types. The misclassification rate of land-cover types was 10.8% based on Ikonos imagery, 22.6% for panchromatic aerial photos and 39.2% for Landsat TM 7 imagery. The Ikonos image identified 40.6% of aquatic habitats, aerial photos identified 10.6%, and Landsate TM 7 image identified 0%. Computer models based on topographic features and land-cover information obtained from the Ikonos image yielded a misclassification rate of 20.3-22.7% for aquatic habitats, and 18.1-25.1% for anopheline-positive larval habitats. One-metre spatial resolution Ikonos images combined with computer modelling based on topographic land-cover features are useful tools for identification of anopheline larval habitats, and they can be used to assist to malaria vector control in western Kenya highlands.

  20. Safety of methionine, a novel biopesticide, to adult and larval honey bees (Apis mellifera L.).

    Science.gov (United States)

    Weeks, Emma N I; Schmehl, Daniel R; Baniszewski, Julie; Tomé, Hudson V V; Cuda, James P; Ellis, James D; Stevens, Bruce R

    2018-03-01

    Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Nutritional ecology of blowflies (Diptera, Calliphoridae: estimates of critical larval weight for pupation on two different

    Directory of Open Access Journals (Sweden)

    Cássio da Silva Ribeiro

    2010-01-01

    Full Text Available Under natural environmental conditions, blowflies utilize discrete and ephemeral feeding resources such as decaying carcasses. Competition for food on such feeding substrates is usually very severe, and only the individuals that are capable of attaining the critical larval weight for pupation will be able to survive. This critical weight is hitherto unknown for several blowfly species; therefore, the current work is aimed at obtaining such a critical value for four blowfly species of the genera Chrysomya and Lucilia, deploying two types of feeding substrate, namely, artificial diet and macerated bovine meat. On the whole, the critical weights ranged from 30 to 35 mg. The lowest larval weight which permitted pupation was 30.0 mg for Chrysomya megacephala reared on macerated bovine meat. This species was also the best adapted to pupation at low larval weights in relation to the maximum larval weight for males. Regarding the pupation of females, the best-adapted individual was a C. albiceps specimen exhibiting a critical weight that was equal to 39.20 % of the maximum value obtained. Concerning all the species and diet types, the female individuals exhibited the lowest critical weights that produced viable pupae, probably representing an evolutionary strategy that favoured the survival of females, responsible for the egg formation, contributing to the establishment of future generations. Regarding the loss (in percentage of adult biomass in relation to the third instar larvae, the females of C. megacephala lost less weight than males in both feeding substrates. On the other hand, such a loss of weight occurred in males of C. albiceps and L. cuprina.

  2. Larval Behavior and Natural Trace Element Signatures as Indicators of Crustacean Population Connectivity

    OpenAIRE

    Miller, Seth Haylen

    2011-01-01

    In an era of increasing governmental protection of marine resources and accelerating climate change, knowing how benthic populations of marine organisms are connected is of paramount importance. However, little is known about connectivity in the nearshore environment, particularly at ecologically and demographically relevant scales. Because the dispersive larval stage is the key to understanding population connectivity, my dissertation focused on developing a new technique for tracking larvae...

  3. Terrestrial vegetation and aquatic chemistry influence larval mosquito abundance in catch basins, Chicago, USA

    Directory of Open Access Journals (Sweden)

    Gardner Allison M

    2013-01-01

    Full Text Available Abstract Background An important determinant of mosquito-borne pathogen transmission is the spatial distribution of vectors. The primary vectors of West Nile virus (WNV in Illinois are Culex pipiens Linnaeus (Diptera: Culicidae and Culex restuans Theobald. In urban environments, these mosquitoes commonly oviposit in roadside storm water catch basins. However, use of this habitat is inconsistent, with abundance of larvae varying significantly across catch basins at a fine spatial scale. Methods We tested the hypothesis that attributes of the biotic and abiotic environment contribute to spatial and temporal variation in production of mosquito vectors, characterizing the relationship between terrestrial vegetation and aquatic chemistry and Culex abundance in Chicago, Illinois. Larvae were sampled from 60 catch basins from June 14 to October 3, 2009. Density of shrubs and 14 tree genera surrounding the basins were quantified, as well as aquatic chemistry content of each basin. Results We demonstrate that the spatial pattern of Culex abundance in catch basins is strongly influenced by environmental characteristics, resulting in significant variation across the urban landscape. Using regression and machine learning techniques, we described landscape features and microhabitat characteristics of four Chicago neighborhoods and examined the implications of these measures for larval abundance in adjacent catch basins. The important positive predictors of high larval abundance were aquatic ammonia, nitrates, and area of shrubs of height Culex during the fruit-bearing periods and early senescent periods in August and September. Conclusions This study identifies environmental predictors of mosquito production in urban environments. Because an abundance of adult Culex is integral to efficient WNV transmission and mosquitoes are found in especially high densities near larval habitats, identifying aquatic sites for Culex and landscape features that promote

  4. The Effects of Biopesticide Azadirachtin on the Fifth Instar Galleria mellonella L. (Lepidoptera: Pyralidae) Larval Integument

    OpenAIRE

    Ünsal, Sadettin; Güner, Emine

    2016-01-01

    The chitin synthesis inhibitory (CSI) effects of azadirachtin on the fifth instar Galleria mellonella L. larval integument were investigated. Using probit analysis, the LC95 value for G. mellonella larvae was detected as 3991 ppm. In this study, 3991 ppm and the reduced 1995, 997, and 498 ppm concentrations were used. It was observed that azadirachtin had different effects on the integument when the larvae were fed semi-synthetic feed containing 498, 997, 1995, or 3991 ppm azadirachtin. Morph...

  5. Depletion of juvenile hormone esterase extends larval growth in Bombyx mori.

    Science.gov (United States)

    Zhang, Zhongjie; Liu, Xiaojing; Shiotsuki, Takahiro; Wang, Zhisheng; Xu, Xia; Huang, Yongping; Li, Muwang; Li, Kai; Tan, Anjiang

    2017-02-01

    Two major hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulate insect growth and development according to their precisely coordinated titres, which are controlled by both biosynthesis and degradation pathways. Juvenile hormone esterase (JHE) is the primary JH-specific degradation enzyme that plays a key role in regulating JH titers, along with JH epoxide hydrolase (JHEH) and JH diol kinase (JHDK). In the current study, a loss-of-function analysis of JHE in the silkworm, Bombyx mori, was performed by targeted gene disruption using the transgenic CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases) system. Depletion of B. mori JHE (BmJHE) resulted in the extension of larval stages, especially the penultimate and ultimate larval stages, without deleterious effects to silkworm physiology. The expression of JHEH and JHDK was upregulated in mutant animals, indicating the existence of complementary routes in the JH metabolism pathway in which inactivation of one enzyme will activate other enzymes. RNA-Seq analysis of mutant animals revealed that genes involved in protein processing in the endoplasmic reticulum and in amino acid metabolism were affected by BmJHE depletion. Depletion of JHE and subsequent delayed JH metabolism activated genes in the TOR pathway, which are ultimately responsible for extending larval growth. The transgenic Cas9 system used in the current study provides a promising approach for analysing the actions of JH, especially in nondrosophilid insects. Furthermore, prolonging larval stages produced larger larvae and cocoons, which is greatly beneficial to silk production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Individual and mixture effects of selected pharmaceuticals on larval development of the estuarine shrimp Palaemon longirostris.

    Science.gov (United States)

    González-Ortegón, Enrique; Blasco, Julian; Nieto, Elena; Hampel, Miriam; Le Vay, Lewis; Giménez, Luis

    2016-01-01

    Few ecotoxicological studies incorporate within the experimental design environmental variability and mixture effects when assessing the impact of pollutants on organisms. We have studied the combined effects of selected pharmaceutical compounds and environmental variability in terms of salinity and temperature on survival, development and body mass of larvae of the estuarine shrimp Palaemon longirostris. Drug residues found in coastal waters occur as mixture, and the evaluation of combined effects of simultaneously occurring compounds is indispensable for their environmental risk assessment. All larval stages of P. longirostris were exposed to the nonsteroidal anti-inflammatory drug (NSAID) diclofenac sodium (DS: 40 and 750 μg L(-1)), the lipid regulator clofibric acid (CA: 17 and 361 μg L(-1)) and the fungicide clotrimazole (CLZ: 0.14 and 4 μg L(-1)). We observed no effect on larval survival of P. longirostris with the tested pharmaceuticals. However, and in contrast to previous studies on larvae of the related marine species Palaemon serratus, CA affected development through an increase in intermoult duration and reduced growth without affecting larval body mass. These developmental effects in P. longirostris larvae were similar to those observed in the mixture of DS and CA confirming the toxic effects of CA. In the case of CLZ, its effects were similar to those observed previously in P. serratus: high doses affected development altering intermoult duration, tended to reduce the number of larval instars and decreased significantly the growth rate. This study suggests that an inter-specific life histories approach should be taken into account to assess the effect of emergent compounds in coastal waters. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Reactivation of larval keratin gene (krt62.L) in blastema epithelium during Xenopus froglet limb regeneration.

    Science.gov (United States)

    Satoh, Akira; Mitogawa, Kazumasa; Saito, Nanami; Suzuki, Miyuki; Suzuki, Ken-Ichi T; Ochi, Haruki; Makanae, Aki

    2017-12-15

    Limb regeneration is considered a form of limb redevelopment because of the molecular and morphological similarities. Forming a regeneration blastema is, in essence, creating a developing limb bud in an adult body. This reactivation of a developmental process in a mature body is worth studying. Xenopus laevis has a biphasic life cycle that involves distinct larval and adult stages. These distinct developmental stages are useful for investigating the reactivation of developmental processes in post-metamorphic frogs (froglets). In this study, we focused on the re-expression of a larval gene (krt62.L) during Xenopus froglet limb regeneration. Recently renamed krt62.L, this gene was known as the larval keratin (xlk) gene, which is specific to larval-tadpole stages. During limb regeneration in a froglet, krt62.L was re-expressed in a basal layer of blastema epithelium, where adult-specific keratin (Krt12.6.S) expression was also observable. Nerves produce important regulatory factors for amphibian limb regeneration, and also play a role in blastema formation and maintenance. The effect of nerve function on krt62.L expression could be seen in the maintenance of krt62.L expression, but not in its induction. When an epidermis-stripped limb bud was grafted in a froglet blastema, the grafted limb bud could reach the digit-forming stage. This suggests that krt62.L-positive froglet blastema epithelium is able to support the limb development process. These findings imply that the developmental process is locally reactivated in an postmetamorphic body during limb regeneration. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Genetic Localization of Foraging (For): A Major Gene for Larval Behavior in Drosophila Melanogaster

    OpenAIRE

    de-Belle, J. S.; Hilliker, A. J.; Sokolowski, M. B.

    1989-01-01

    Localizing genes for quantitative traits by conventional recombination mapping is a formidable challenge because environmental variation, minor genes, and genetic markers have modifying effects on continuously varying phenotypes. We describe ``lethal tagging,'' a method used in conjunction with deficiency mapping for localizing major genes associated with quantitative traits. Rover/sitter is a naturally occurring larval foraging polymorphism in Drosophila melanogaster which has a polygenic pa...

  9. Induction of Larval Metamorphosis of the Coral Acropora millepora by Tetrabromopyrrole Isolated from a Pseudoalteromonas Bacterium

    Science.gov (United States)

    Tebben, Jan; Tapiolas, Dianne M.; Motti, Cherie A.; Abrego, David; Negri, Andrew P.; Blackall, Linda L.; Steinberg, Peter D.; Harder, Tilmann

    2011-01-01

    The induction of larval attachment and metamorphosis of benthic marine invertebrates is widely considered to rely on habitat specific cues. While microbial biofilms on marine hard substrates have received considerable attention as specific signals for a wide and phylogenetically diverse array of marine invertebrates, the presumed chemical settlement signals produced by the bacteria have to date not been characterized. Here we isolated and fully characterized the first chemical signal from bacteria that induced larval metamorphosis of acroporid coral larvae (Acropora millepora). The metamorphic cue was identified as tetrabromopyrrole (TBP) in four bacterial Pseudoalteromonas strains among a culture library of 225 isolates obtained from the crustose coralline algae Neogoniolithon fosliei and Hydrolithon onkodes. Coral planulae transformed into fully developed polyps within 6 h, but only a small proportion of these polyps attached to the substratum. The biofilm cell density of the four bacterial strains had no influence on the ratio of attached vs. non-attached polyps. Larval bioassays with ethanolic extracts of the bacterial isolates, as well as synthetic TBP resulted in consistent responses of coral planulae to various doses of TBP. The lowest bacterial density of one of the Pseudoalteromonas strains which induced metamorphosis was 7,000 cells mm−2 in laboratory assays, which is on the order of 0.1 –1% of the total numbers of bacteria typically found on such surfaces. These results, in which an actual cue from bacteria has been characterized for the first time, contribute significantly towards understanding the complex process of acroporid coral larval settlement mediated through epibiotic microbial biofilms on crustose coralline algae. PMID:21559509

  10. Feeding, growth, and survival of post-larval abalone Haliotis asinina on different benthic diatoms

    Directory of Open Access Journals (Sweden)

    Emmanuel C. Capinpin, Jr.

    2007-12-01

    Full Text Available The feeding behavior, digestive efficiency, growth, and survival of post-larval abalone Haliotis asininafed with 5 species of locally isolated benthic diatom strains (Navicula mollis, N. ramosissima, Stauroneissp., Pleurosigma sp., and Cocconeis sp. were examined in the laboratory. Two 15-day feeding trialsusing 1 mm post-larvae were conducted. No significant differences were observed in sizes of post-larvalabalone after 15 days in all diatom treatments (P>0.05. However, in both trials, Cocconeis sp. resulted inhigh survival rates (88.9±5.6% and 80.0±20.0% for Trials 1 and 2, respectively. Cocconeis sp. wasefficiently digested by post-larval abalone, with most of the cells being ruptured during ingestion and/orpassage through the gut. One diatom strain, Pleurosigma sp., resulted to a high survival but producedthe slowest growth rate (<10 ìm.d-1 SL. It was probably not ingested easily during the experiment due toits large size or mobility. For the other diatom strains, N. mollis and N. ramosissima, most cells passedthrough the gut with the cells left intact. Stauroneis sp. is highly digestible, but did not result to highsurvival, although the remaining live post-larval abalone fed on this diatom as well as on N. mollis grewfaster during the second week of both feeding trials. N. ramosissima resulted to poorest survival rate(<10% due to its poor digestibility. Only Cocconeis sp. showed a fairly high growth rate, digestionefficiency, and survival rate. N. mollis which gave a fairly high survival rate and Stauroneis may be addedtowards the later stages of post-larval rearing as well as other large diatoms. The digestion efficiency ofdiatom strains is considered an important factor determining its dietary value, but other factors may alsobe important such as volume contents, biochemical composition, and other physical characteristics.

  11. Combinatorial action of Grainyhead, Extradenticle and Notch in regulating Hox mediated apoptosis in Drosophila larval CNS.

    Science.gov (United States)

    Khandelwal, Risha; Sipani, Rashmi; Govinda Rajan, Sriivatsan; Kumar, Raviranjan; Joshi, Rohit

    2017-10-01

    Hox mediated neuroblast apoptosis is a prevalent way to pattern larval central nervous system (CNS) by different Hox genes, but the mechanism of this apoptosis is not understood. Our studies with Abdominal-A (Abd-A) mediated larval neuroblast (pNB) apoptosis suggests that AbdA, its cofactor Extradenticle (Exd), a helix-loop-helix transcription factor Grainyhead (Grh), and Notch signaling transcriptionally contribute to expression of RHG family of apoptotic genes. We find that Grh, AbdA, and Exd function together at multiple motifs on the apoptotic enhancer. In vivo mutagenesis of these motifs suggest that they are important for the maintenance of the activity of the enhancer rather than its initiation. We also find that Exd function is independent of its known partner homothorax in this apoptosis. We extend some of our findings to Deformed expressing region of sub-esophageal ganglia where pNBs undergo a similar Hox dependent apoptosis. We propose a mechanism where common players like Exd-Grh-Notch work with different Hox genes through region specific enhancers to pattern respective segments of larval central nervous system.

  12. Molecular phylogeny and larval morphological diversity of the lanternfish genus Hygophum (Teleostei: Myctophidae).

    Science.gov (United States)

    Yamaguchi, M; Miya, M; Okiyama, M; Nishida, M

    2000-04-01

    Larvae of the deep-sea lanternfish genus Hygophum (Myctophidae) exhibit a remarkable morphological diversity that is quite unexpected, considering their homogeneous adult morphology. In an attempt to elucidate the evolutionary patterns of such larval morphological diversity, nucleotide sequences of a portion of the mitochondrially encoded 16S ribosomal RNA gene were determined for seven Hygophum species and three outgroup taxa. Secondary structure-based alignment resulted in a character matrix consisting of 1172 bp of unambiguously aligned sequences, which were subjected to phylogenetic analyses using maximum-parsimony, maximum-likelihood, and neighbor-joining methods. The resultant tree topologies from the three methods were congruent, with most nodes, including that of the genus Hygophum, being strongly supported by various tree statistics. The most parsimonious reconstruction of the three previously recognized, distinct larval morphs onto the molecular phylogeny revealed that one of the morphs had originated as the common ancestor of the genus, the other two having diversified separately in two subsequent major clades. The patterns of such diversification are discussed in terms of the unusual larval eye morphology and geographic distribution. Copyright 2000 Academic Press.

  13. Contrasting effects of heavy metals and hydrocarbons on larval settlement and juvenile survival in sponges

    International Nuclear Information System (INIS)

    Cebrian, E.; Uriz, M.J.

    2007-01-01

    Metals and polycyclic aromatic hydrocarbons (PAHs) contaminate sediments and waters of coastal areas threatening early stages of invertebrate development. Effects on these stages may largely determine the decline and even disappearance of invertebrate populations in polluted environments. Our study aimed to determine the possible influence of metals (Cu and Cd) and PAHs on larval settlement and consecutive survival of two widespread sponges of the Mediterranean: Crambe crambe and Scopalina lophyropoda. Larvae of both species were exposed to Cu and Cd for a short period during 1 week, and settlement and following (6 months) survival of juvenile were monitored. Short exposures to copper and cadmium at the concentrations used did not affect C. crambe settlement compared with SW control, and no effect on consecutive survival of juveniles was observed. In contrast, short pulses of copper and cadmium at the concentrations used enhanced Scopalina lophyropoda settlement and did not affect the consecutive survival of juveniles with respect to SW controls. Furthermore, experiments designed to assess the effects of short exposures to PAHs and the combined effect of contamination by Cu 2+ and PAHs on larval settlement, were conduced during 10 days on C. crambe larvae. Hydrocarbons, differently than copper and cadmium, inhibited the settlement of sponge larvae to a certain extent. The synergetic negative effect of copper and hydrocarbons on C. crambe settlers may cause a decline of populations in areas with both sources of contamination. The present study provides the only available data on toxicity of copper, cadmium and hydrocarbon toxicants on sponge larval settlement

  14. Mosquito (Diptera: Culicidae) grouping based on larval habitat characteristics in high mountain ecosystems of Antioquia, Colombia.

    Science.gov (United States)

    Rosero-García, Doris; Rúa-Uribe, Guillermo; Correa, Margarita M; Conn, Jan E; Uribe-Soto, Sandra

    2018-06-01

    Information about mosquito ecology in the high mountain ecosystems of the Neotropical region is sparse. In general, few genera and species have been reported in these ecosystems and there is no information available on habitats and the mosquitoes occupying them. In the present study, specimens collected from NW Colombia in HME were grouped using larval habitat data via an Operational Taxonomic Unit (OTU) determination. A total of 719 mosquitoes was analyzed belonging to 44 OTUs. The analysis considered habitat features and clustered the specimens into six groups from A-F. Five of these included species from different genera, suggesting common habitat requirements. Group E with four genera, seven subgenera, and six species occupied the highest areas (above 3,000 m), whereas three groups (B, D, F) were detected at lower altitudes (1,960-2,002 m). Bromeliads were the most common larval habitat, with 47% (335/719) of the specimens; five genera, six subgenera, and eight species were identified and classified into 66% (29/44) of the OTUs. This work showed some similarities to the habitat requirements and provides a grouping system that constitutes an important baseline for the classification of mosquito fauna from high mountain ecosystems according to altitude and larval habitat. © 2018 The Society for Vector Ecology.

  15. Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Kho, Elise A; Hugo, Leon E; Lu, Guangjin; Smith, David D; Kay, Brian H

    2016-07-01

    In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Comparative evaluation of sea-urchin larval stage sensitivity to ocean acidification.

    Science.gov (United States)

    Passarelli, M C; Cesar, A; Riba, I; DelValls, T A

    2017-10-01

    Changes in the marine carbonate system may affect various calcifying organisms. This study is aimed to compare the sensitivity of embryo-larval development of two species of sea urchins (Paracentrutos lividus and Lytechinus variegatus) collected and exposed to samples from different coastal zone (Spain and Brazil) to ocean acidification. The results showed that the larval stages are very sensitive to small changes in the seawater's pH. The larvae from P. lividus species showed to be more sensitive to acidified elutriate sediments than larvae from L. variegatus sea urchin. Furthermore, this study has demonstrated that the CO 2 enrichment in aquatic ecosystems cause changes on the mobility of the metals: Zn, Cu, Fe, Al and As, which was presented different behavior among them. Although an increase on the mobility of metals was found, the results using the principal component analysis showed that the pH reduction show the highest correlations with the toxicity and is the main cause of embryo-larval development inhibition. In this comparative study it is demonstrated that both species are able to assess potential effects of the ocean acidification related to CO 2 enrichment by both near future scenarios and the risk associated with CO 2 leakages in the Carbon Capture and Storage (CCS) process, and the importance of comparative studies in different zones to improve the understanding of the impacts caused by ocean acidification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Larval vision contributes to gregarious settlement in barnacles: adult red fluorescence as a possible visual signal

    KAUST Repository

    Matsumura, K.

    2014-02-26

    Gregarious settlement, an essential behavior for many barnacle species that can only reproduce by mating with a nearby barnacle, has long been thought to rely on larval ability to recognize chemical signals from conspecifics during settlement. However, the cyprid, the settlement stage larva in barnacles, has one pair of compound eyes that appear only at the late nauplius VI and cyprid stages, but the function(s) of these eyes remains unknown. Here we show that cyprids of the intertidal barnacle Balanus (=Amphibalanus) amphitrite can locate adult barnacles even in the absence of chemical cues, and prefer to settle around them probably via larval sense of vision. We also show that the cyprids can discriminate color and preferred to settle on red surfaces. Moreover, we found that shells of adult B. amphitrite emit red auto-fluorescence and the adult extracts with the fluorescence as a visual signal attracted cyprid larvae to settle around it. We propose that the perception of specific visual signals can be involved in behavior of zooplankton including marine invertebrate larvae, and that barnacle auto-fluorescence may be a specific signal involved in gregarious larval settlement.

  18. Flexible responses to visual and olfactory stimuli by foraging Manduca sexta: larval nutrition affects adult behaviour.

    Science.gov (United States)

    Goyret, Joaquín; Kelber, Almut; Pfaff, Michael; Raguso, Robert A

    2009-08-07

    Here, we show that the consequences of deficient micronutrient (beta-carotene) intake during larval stages of Manduca sexta are carried across metamorphosis, affecting adult behaviour. Our manipulation of larval diet allowed us to examine how developmental plasticity impacts the interplay between visual and olfactory inputs on adult foraging behaviour. Larvae of M. sexta were reared on natural (Nicotiana tabacum) and artificial laboratory diets containing different concentrations of beta-carotene (standard diet, low beta-carotene, high beta-carotene and cornmeal). This vitamin-A precursor has been shown to be crucial for photoreception sensitivity in the retina of M. sexta. After completing development, post-metamorphosis, starved adults were presented with artificial feeders that could be either scented or unscented. Regardless of their larval diet, adult moths fed with relatively high probabilities on scented feeders. When feeders were unscented, moths reared on tobacco were more responsive than moths reared on beta-carotene-deficient artificial diets. Strikingly, moths reared on artificial diets supplemented with increasing amounts of beta-carotene (low beta and high beta) showed increasing probabilities of response to scentless feeders. We discuss these results in relationship to the use of complex, multi-modal sensory information by foraging animals.

  19. Investigating the embryo/larval toxic and genotoxic effects of {gamma} irradiation on zebrafish eggs

    Energy Technology Data Exchange (ETDEWEB)

    Simon, O., E-mail: olivier.simon@irsn.fr [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Massarin, S. [Laboratoire de Modelisation Environnementale, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Coppin, F. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Hinton, T.G. [Service d' Etude du Comportement des Radionucleides dans les Ecosystemes, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Gilbin, R. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France)

    2011-11-15

    Eggs/larval of freshwater fish (Danio rerio) were exposed to low dose rates of external gamma radiation (from 1 to 1000 mGy d{sup -1}) over a 20-day period, with the objective of testing the appropriateness of the 10 mGy d{sup -1} guideline suggested by the IAEA. The present study examines different endpoints, mortality and hatching time and success of embryos as well as the genotoxicity of {gamma}-irradiations (after 48 h). The 20-day embryo-larval bioassay showed an enhanced larval resistance to starvation after chronic exposure to {gamma} irradiation (from low 1 mGy d{sup -1} to high dose rate 1000 mGy d{sup -1}) and an acceleration in hatching time. Gamma irradiation led to increased genotoxic damage Ito zebrafish egg (40-50% DNA in tail in Comet assay) from the lowest dose rate (1 mGy d{sup -1}). Possible mechanisms of {gamma} radiotoxicity and implications for radioprotection are discussed. - Highlights: > Relevant information on the {gamma} radiation impact on early life stage biota is scarce. > The eggs of zebrafish Danio rerio were selected as biological model. > We test the appropriateness of the 10 mGy d{sup -1} guideline (IAEA). > We observed effects measured at individual levels (starvation, hatching time). > Chronic gamma irradiation led to increased genotoxic damage to zebrafish egg. > {gamma} radiotoxicity mechanisms and implications for radioprotection are discussed.

  20. The post-larval and juvenile fish assemblage in the Sukhothai floodplain, Thailand

    Science.gov (United States)

    Siriwan, Suksri; Boonsatien, Boonsoong

    2017-06-01

    This study investigated abundance, species composition and spatial and temporal distributions of fish larvae and their relationship with some environmental variables in the Sukhothai floodplain in northern Thailand. Fish larvae were collected from 33 sampling stations on 8 occasions between August 2010 and October 2013. The study collected and identified 149 296 individuals, representing 32 families and 165 taxa. The species composition of larval fish was dominated by the Cyprinidae (47.27%), Cobitidae (7.88%), Siluridae (6.67%), Bagridae (6.06%) and Mastacembelidae (3.33%) families. The most-abundant larval species were the Striped flying barb Esomus metallicus (16.90%), the Siamese mud carp Henicorhynchus siamensis (8.48%) and the Sumatran river sprat Clupeichthys goniognathus (8.31%). The greatest abundance and species diversity of larvae were found when the river flow runs onto the floodplain. PCA and nMDS analysis revealed that the samples plot is associated with temporal distribution among years. The discharge was a major factor determining fish larvae assemblage and environmental variables in the Sukhothai floodplain. Four fish larval species were positively correlated with the samples for 2013. The result of the CCA ordination plot showed that only the discharge variable was strongly correlated with fish larvae abundance, especially two cyprinid Rasbora species.

  1. Effects of fenoxycarb exposure on complete larval development of the xanthid crab, Rhithropanopeus harrisii

    International Nuclear Information System (INIS)

    Cripe, G.M.; McKenney, C.L.; Hoglund, M.D.; Harris, P.S.

    2003-01-01

    The pest control agent fenoxycarb reduced survival and extended duration of developing larval stages in the xanthid crab, Rhithropanopeus harrisii. - Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 μg fenoxycarb/l and in megalopae exposed to 48 μg fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments ≥48 μg/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to ≥48 μg/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary

  2. A model of the evolution of larval feeding rate in Drosophila driven by conflicting energy demands.

    Science.gov (United States)

    Mueller, Laurence D; Barter, Thomas T

    2015-02-01

    Energy allocation is believed to drive trade-offs in life history evolution. We develop a physiological and genetic model of energy allocation that drives evolution of feeding rate in a well-studied model system. In a variety of stressful environments Drosophila larvae adapt by altering their rate of feeding. Drosophila larvae adapted to high levels of ammonia, urea, and the presence of parasitoids evolve lower feeding rates. Larvae adapted to crowded conditions evolve higher feeding rates. Feeding rates should affect gross food intake, metabolic rates, and efficiency of food utilization. We develop a model of larval net energy intake as a function of feeding rates. We show that when there are toxic compounds in the larval food that require energy for detoxification, larvae can maximize their energy intake by slowing their feeding rates. While the reduction in feeding rates may increase development time and decrease competitive ability, we show that genotypes with lower feeding rates can be favored by natural selection if they have a sufficiently elevated viability in the toxic environment. This work shows how a simple phenotype, larval feeding rates, may be of central importance in adaptation to a wide variety of stressful environments via its role in energy allocation.

  3. EFFECTS OF THALLIUM ON THE LARVAL DEVELOPMENT OF LUCILIA SERICATA MEIGEN 1826 AND PMI ESTIMATION

    Directory of Open Access Journals (Sweden)

    Arif Gökhan BAŞARAN

    2011-08-01

    Full Text Available Determination of larval growth rate of and forensic analysis of the age of Calliphoridae larvae on a corpse are useful evidence in legal investigations for the estimation of exact death time and time duration after death; post mortem interval. However many factors, such as temperature, tissue type and contamination of drugs and toxins, effect larval development of blow fly larvae and consequently theestimation of post mortem interval. The present study examined the larval growth rate of a forensically important blow fly species, Lucilia sericata Meigen 1826 in different concentrations (0,12; 0,25; 0,50; 1 and 2 μg/g of toxic heavy metal Thallium under controlled laboratory conditions. Body length and weight, death ratio of larvae and pupa between experimental and control groups were compared. Results demonstrated that the development rate of larvae between uncontaminated and contaminated diets varies significantly. In short, they molted later, reached maximum length more slowly and sometimesproduced significantly smaller pupae in contaminated food source. These results emphasized that the importance of determining the contamination rate of toxins in tissue for the forensic entomologist,while using development rates from standard curves based on larvae fed non-contaminated mediums.

  4. Larval development of Dagetichthys marginatus (Soleidae obtained from hormone-induced spawning under artificial rearing conditions

    Directory of Open Access Journals (Sweden)

    Ernst F. Thompson

    2007-09-01

    Full Text Available Dagetichthys marginatus (formerly Synaptura marginata larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys, which is represented by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown.

  5. Survival and larval development of Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) on alternatives host

    International Nuclear Information System (INIS)

    Sa, Verissimo G.M. de; Boregas, Katia G.B.

    2009-01-01

    Two bioassays were conducted to evaluate the suitability of host plants of fall armyworm (FAW), Spodoptera frugiperda (J E Smith), in the Brazilian agro-ecosystem. Larval development and survival were analyzed by infesting leaves of maize, grain sorghum, Johnson grass, soybean, Brachiaria and tobacco with FAW newly hatched larvae in a no choice test. No significant differences of survival were observed among insects reared on different hosts, except for tobacco, where no survivors were recorded. Larvae fed on soybean and artificial diet grew larger than those fed on the other hosts. The heaviest pupa was observed from larva fed on artificial diet and the lighter from larva fed on Brachiaria grass. No significant differences were reported on larval development time on natural hosts, but it was longer for larvae reared on artificial diet. Three classes of larval development time were observed on maize, four on sorghum, Brachiaria and soybean, and five on artificial diet. Nearly 85% of FAW larvae completed development within 12 d on maize; 77% on grain sorghum, 80% on Johnson grass, 68% on Brachiaria and 83% on soybean within 14 d and 69% on artificial diet within 17 d. The host suitability to FAW decreases from maize to sorghum, soybean and Brachiaria. (author)

  6. Diet of larval albacore Thunnus alalunga (Bonnaterre, 1788 off Mallorca Island (NW Mediterranean

    Directory of Open Access Journals (Sweden)

    Ignacio Alberto Catalán

    2007-06-01

    Full Text Available These are the first data on the feeding of larval albacore (Thunnus alalunga Bonnaterre, 1788 in the Mediterranean. Specimens were gathered from day-time bongo-hauls conducted over the SW Mallorcan (Balearic Islands shelf-slope. Ninety eight percent of 101 individuals ranging from 2.65 to 9.4 mm standard length (SL contained 1 to 15 prey items per gut. Mean number of prey/gut was 3.55 ± 2.19 (SD. A positive correlation was found between larval SL and the number of prey/gut. The analysis of frequency of occurrence (F, numerical frequency (N, weight frequency (W and the Index of Relative Importance (IRI showed a dominance of copepodites and nauplii in the smallest size-class. As larvae grew, cladocerans and Calanoida copepodites dominated the diet, and cladocerans and copepodites were important in F, N and W. Piscivory was observed after notochord flexion and was important in terms of W. A positive correlation between mean prey size and both SL and lower jaw length (LJL was observed. The niche breadth (S did not vary with LJL, but the raw prey size range did. Larger copepodites, the absence of nauplii and the incorporation of fish larvae and a larger number of cladocerans in the diet accounted for the increase in mean prey size through increased larval size.

  7. Influence of habitat structure and environmental variables on larval fish assemblage in the Johor Strait, Malaysia.

    Science.gov (United States)

    Ara, Roushon; Arshad, Aziz; Amin, S M Nurul; Idris, M H; Gaffar, Mazlan Abd; Romano, Nicholas

    2016-07-01

    Our previous study demonstrated that among different habitat sites (mangrove, estuary, river, seagrass and Open Sea) in Johor Strait, Malaysia, seagrass showed highest family diversity and abundance of larval fish. However, it is unclear whether this was due to difference in habitat complexity or water quality parameters.? To test this, larval fish were collected by using a bongo net equipped with a flow meter by subsurface horizontal towing from different habitats in Johor Strait between October 2007 and September 2008.? Various physico-chemical parameters were measured and then examined for any relationship to fish larvae diversity and abundance. Among the 24 families identified from the sites, seven families (Blenniidae, Clupeidae, Mullidae, Nemipteridae, Syngnathidae, Terapontidae and Uranoscopeidae) were significantly correlated with the tested waters quality parameters.? Salinity showed a positive and negative significant correlation with Clupeidae (p Johor Strait, Malaysia. This likely indicates that habitat structure was more important in determining larval abundance (highest in the seagrass habitat) as compared to water quality at the tested sites. This study emphasizes the need to conserve seagrass beds as important nursery grounds for various fish larvae to ensure adequate recruitment and ultimately sustainable fisheries management. ?

  8. Copper affects biofilm inductiveness to larval settlement of the serpulid polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Bao, Wei Yang; Lee, On On; Chung, Hong Chun; Li, Mu; Qian, Pei Yuan

    2010-01-01

    Copper (Cu) contamination is a potential threat to the marine environment due to the use of Cu-based antifouling paints. Cu stress on larval settlement of the polychaete Hydroides elegans was investigated, and this was linked to Cu stress on biofilms and on the biofilm development process. The inductiveness of young biofilms was more easily altered by Cu stress than that of old biofilms, indicating the relative vulnerability of young biofilms. This might result from changes in bacterial survival, the bacterial community composition and the chemical profiles of young biofilms. Cu also affected biofilm development and the chemical high performance liquid chromatograph fingerprint profile. The results indicate that Cu affected larval settlement mainly through its effect on the process of biofilm development in the marine environment, and the chemical profile was crucial to biofilm inductiveness. It is strongly recommended that the effects of environmentally toxic substances on biofilms are evaluated in ecotoxicity bioassays using larval settlement of invertebrates as the end point. © 2010 Taylor & Francis.

  9. Hatching and larval export of the intertidal crab Neohelice granulata in Mar Chiquita coastal lagoon, Argentina

    Directory of Open Access Journals (Sweden)

    Guillermina Sánchez Vuichard

    2013-06-01

    Full Text Available Synchronization in the events of the reproductive cycle in female Neohelice granulata Dana, 1851 were studied from samples taken weekly and biweekly from September to December 2006 in the Laguna Mar Chiquita. The timing and larval hatching and synchronicity were inferred from numbers of ovigerous females and observing the stages of embryonic development. Synchronization in larval hatching also was observed in females in experiments in dark for a period of 48 hours, at three different salinities (10, 23 and 33 ppm. In addition plankton sampling were performed in order to study larval exportation at the field and its link to the tidal and light/dark cycles. We found that ovigerous females of N. granulata have a marked synchronization in embryonic development which results in that most of berried females are close to hatching within a period of maximum tidal range (days. Within this period, there is a synchronization of hatching at a time scale of hours, governed by environmental conditions. The salinity range used in this study (10-32‰ did not affect hatching synchronicity neither time to hatch. Hatching was synchronized according to endogenous rhythms governed mainly by the tidal cycle and secondarily by the breadth of it. It is also conditioned by the light-dark cycle through an exogenous cycle, so that the hatchings would occur mostly at night high tides.

  10. Growth pattern and growth dependent mortality of larval and pelagic juvenile North Sea cod Gadus morhua

    DEFF Research Database (Denmark)

    Nielsen, Rune; Munk, Peter

    2004-01-01

    and May 2001), and larval/juvenile growth history from each of the sampling sequences was outlined. Growth rate was estimated by fitting a Laird-Gompertz equation to lengths-at-age, and we found the mean specific growth rate in length at age 20 d was 3.2% d(-1), declining to 1.9% d(-1) at an age of 90 d....... Otolith radius and larval standard length were highly correlated, and otolith growth was used as a measure of larval somatic growth. The larvae were divided into 3 groups dependent on their hatch-date, and for each hatch group, the same period of past growth was compared between fish sampled in April...... and May. A 2-way repeated-measurement ANOVA revealed a significant higher past growth of fish sampled in May in 2 of the 3 hatch-groups, implying a higher mortality of the slow growing larvae. Additionally, otolith size at age differed significantly between the April and May sampling of the oldest larvae...

  11. Effects of fenoxycarb exposure on complete larval development of the xanthid crab, Rhithropanopeus harrisii

    Energy Technology Data Exchange (ETDEWEB)

    Cripe, G.M.; McKenney, C.L.; Hoglund, M.D.; Harris, P.S

    2003-09-01

    The pest control agent fenoxycarb reduced survival and extended duration of developing larval stages in the xanthid crab, Rhithropanopeus harrisii. - Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 {mu}g fenoxycarb/l and in megalopae exposed to 48 {mu}g fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments {>=}48 {mu}g/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to {>=}48 {mu}g/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary.

  12. Analysis of synaptic growth and function in Drosophila with an extended larval stage.

    Science.gov (United States)

    Miller, Daniel L; Ballard, Shannon L; Ganetzky, Barry

    2012-10-03

    The Drosophila larval neuromuscular junction (NMJ) is a powerful system for the genetic and molecular analysis of neuronal excitability, synaptic transmission, and synaptic development. However, its use for studying age-dependent processes, such as maintenance of neuronal viability and synaptic stability, are temporally limited by the onset of pupariation and metamorphosis. Here we characterize larval NMJ growth, growth regulation, structure, and function in a developmental variant with an extended third instar (ETI). RNAi-knockdown of the prothoracicotropic hormone receptor, torso, in the ring gland of developing larvae leaves the timing of first and second instar molts largely unchanged, but triples duration of the third instar from 3 to 9.5 d (McBrayer et al., 2007; Rewitz et al., 2009). During this ETI period, NMJs undergo additional growth (adding >50 boutons/NMJ), and this growth remains under the control of the canonical regulators Highwire and the TGFβ/BMP pathway. NMJ growth during the ETI period occurs via addition of new branches, satellite boutons, and interstitial boutons, and continues even after muscle growth levels off. Throughout the ETI, organization of synapses and active zones remains normal, and synaptic transmission is unchanged. These results establish the ETI larval system as a viable model for studying motor neuron diseases and for investigating time-dependent effects of perturbations that impair mechanisms of neuroprotection, synaptic maintenance, and response to neural injury.

  13. Diatom diet selectivity by early post-larval abalone Haliotis diversicolor supertexta under hatchery conditions

    Science.gov (United States)

    Zhang, Yuyu; Gao, Yahui; Liang, Junrong; Chen, Changping; Zhao, Donghai; Li, Xuesong; Li, Yang; Wu, Wenzhong

    2010-11-01

    Benthic diatoms constitute the primary diet of abalone during their early stages of development. To evaluate the dietary preferences of early post-larval abalone, Haliotis diversicolor supertexta, we analyzed the gut contents of post-larvae that settled on diatom films. We compared the abundance and species diversity of diatom assemblages in the gut to those of the epiphytic diatom assemblages on the attachment films, and identified 40 benthic diatom species in the gut contents of post-larvae 12 to 24 d after settlement. The most abundant taxa in the gut contents were Navicula spp., Amphora copulate, and Amphora coffeaeformis. Navicula spp. accounted for 64.0% of the cell density. In the attachment films, we identified 110 diatom species belonging to 38 genera. Pennate diatoms were the dominant members including the species Amphiprora alata, Cocconeis placentula var. euglypta, Cylindrotheca closterium, Navicula sp. 2, and A. coffeaeformis. Nano-diatoms (abalone seed. The difference of the composition and abundance of diatoms between in the guts and on the biofilms suggests that early post-larval grazing was selective. An early post-larval abalone preferred nano-diatoms and the genera Navicula and Amphora during the month after settlement.

  14. Effects of temperature and dietary nitrogen on genetic variation and covariation in gypsy moth larval performance traits

    Directory of Open Access Journals (Sweden)

    Janković-Tomanić Milena

    2012-01-01

    Full Text Available To assess the plastic and genetic components of variation in responses of gypsy moth (Lymantria dispar 4th instar larvae to temperature and food quality, we applied a split-family four-environment experimental design where full-sibs were reared on two constant temperatures (23°C and 28°C and two concentrations of dietary nitrogen (1.5 and 3.7% dry weight. A temperature of 28°C and low dietary nitrogen decreased larval weight and prolonged larval developmental time, while viability was not affected. Only a marginally significant interaction between the two environmental factors was found for larval weight. The broad-sense heritability for larval developmental time did not change across environments, and across-environment genetic correlations were close to one. Heritability for larval weight depended on environmental and across-environmental genetic correlations that were not significant. There was no evidence of a trade-off between developmental time and larval weight. The implications of the obtained results for the evolution of phenotypic plasticity in complex environments are discussed. [Acknowledgments. This work was supported by Ministry of Education and Science of Serbia, grant No. 173027.

  15. Foraging and predation risk for larval cisco (Coregonus artedi) in Lake Superior: a modelling synthesis of empirical survey data

    Science.gov (United States)

    Myers, Jared T.; Yule, Daniel L.; Jones, Michael L.; Quinlan, Henry R.; Berglund, Eric K.

    2014-01-01

    The relative importance of predation and food availability as contributors to larval cisco (Coregonus artedi) mortality in Lake Superior were investigated using a visual foraging model to evaluate potential predation pressure by rainbow smelt (Osmerus mordax) and a bioenergetic model to evaluate potential starvation risk. The models were informed by observations of rainbow smelt, larval cisco, and zooplankton abundance at three Lake Superior locations during the period of spring larval cisco emergence and surface-oriented foraging. Predation risk was highest at Black Bay, ON, where average rainbow smelt densities in the uppermost 10 m of the water column were >1000 ha−1. Turbid conditions at the Twin Ports, WI-MN, affected larval cisco predation risk because rainbow smelt remained suspended in the upper water column during daylight, placing them alongside larval cisco during both day and night hours. Predation risk was low at Cornucopia, WI, owing to low smelt densities (cisco survival at Black Bay and to a lesser extent at Twin Ports, and that starvation may be a major source of mortality at all three locations. The framework we describe has the potential to further our understanding of the relative importance of starvation and predation on larval fish survivorship, provided information on prey resources available to larvae are measured at sufficiently fine spatial scales and the models provide a realistic depiction of the dynamic processes that the larvae experience.

  16. Raising Awareness of Urban Environment Development in Primary Schools

    Directory of Open Access Journals (Sweden)

    Rosi Maja

    2016-12-01

    educate children, toddlers, pupils, students, about the importance of urban environment development and create a positive learning environment, where children are able to develop as residents with a great understanding of the potential of the environment they live in. The paper explores the importance of raising awareness of the urban environment in primary schools from the theoretical, analytical and practical point of views. In the paper, we will examine whether primary schools in the city of Maribor, Slovenia educate children about their urban environment, if they are creating positive learning environments, where children can develop into proud citizens aware of the significance of the urban environment and its consequences for the quality of their lives. Further on, the curricula in chosen primary schools in Maribor is going to be analyzed. With the survey, we will try to identify the degree of children’s awareness of their surrounding urban environment, the information they receive about their environment, and their attitude towards it. And finally, what is most important, we will try to show the extreme significance of the learning environment and the curricula for raising the awareness of the environment and growing into responsible adults who will also act responsibly towards their urban environments.

  17. Minority Capital Resource Handbook. A Guide to Raising Capital for Minority Entrepreneurs. Second Edition.

    Science.gov (United States)

    Ewing, Samuel D., Jr.; Maloney, Clifton H. W.

    This minority capital resource handbook consists of a guide to raising capital for minority entrepreneurs and a listing of sources that provide such capital. The first section deals with the process of raising capital. The realities of raising capital, intermediaries and financial advisors, and assessing needs are outlined. Factors considered in…

  18. 7 CFR 8.9 - Use in 4-H fund raising.

    Science.gov (United States)

    2010-01-01

    ... Office of the Secretary of Agriculture 4-H CLUB NAME AND EMBLEM § 8.9 Use in 4-H fund raising. (a) Fund-raising programs using the 4-H Name or Emblem may be carried out for specific educational purposes. Such fund-raising programs and use of the 4-H name and emblem on, or associated with, products, and services...

  19. Raising Awareness on Heat Related Mortality in Bangladesh

    Science.gov (United States)

    Arrighi, J.; Burkart, K.; Nissan, H.

    2017-12-01

    Extreme heat is the leading cause of weather-related deaths in the United States and Europe, and was responsible for four of the ten deadliest natural disasters worldwide in 2015. Near the tropics, where hot weather is considered the norm, perceived heat risk is often low, but recent heat waves in South Asia have caught the attention of the health community, policy-makers and the public. In a recent collaboration between the Red Cross Red Crescent Climate Centre, Columbia University and BBC Media Action the effects of extreme heat in Bangladesh were analyzed and the findings were subsequently used as a basis to raise awareness about the impacts of extreme heat on the most vulnerable, to the general public. Analysis of excess heat in Bangladesh between 2003 and 2007 showed that heatwaves occur between April and June with most extreme heat events occurring in May. Between 2003 and 2007 it is estimated that an average of 1500 people died per year due to heatwaves lasting three days or longer, with an eight-day heatwave in 2005 resulting in a minimum of 3,800 excess deaths. Utilizing these findings BBC Media Action launched an online communications campaign in May 2017 ultimately reaching approximately 3.9 million people with information on reducing the impacts of extreme heat. This presentation will highlight key findings from the study of heat related mortality in Bangladesh as well as highlight the benefit of collaboration between scientists and communicators for increasing awareness about the effects of extreme heat on the most vulnerable.

  20. Raising H2 and Fuel Cell Awareness in Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Valente, Patrick R. [Ohio Fuel Cell Coalition, Elyria, OH (United States)

    2013-03-31

    The Ohio Fuel Cell Coalition was tasked with raising the awareness and understanding of Fuel Cells and the Hydrogen economy. This was done by increasing the understanding of hydrogen and fuel cell technologies among state and local governments using a target of more than 10% compared to 2004 baseline. We were also to target key populations by 20 percent compared to 2004 baseline. There are many barriers to an educated fuel cell population, including: a)Lack of Readily Available, Objective and Technical Accurate Information b)Mixed Messages c)Disconnect Between Hydrogen Information and Dissemination Networks d)Lack of Educated Trainers and Training Opportunities e)Regional Differences f)Difficulty of Measuring Success The approach we used for all the Community Leaders Forums were presentations by the Ohio Fuel Cell Coalition in conjunction with regional leaders. The presentations were followed by question and answers periods followed up by informal discussions on Fuel Cells and the Hydrogen Economy. This project held a total of 53 events with the following breakdown: From Aug 2009 through June 2010, the Ohio Fuel Cell Coalition held 19 community leaders forums and educated over 845 individuals, both from the State of Ohio and across the country: From July 2010 to June 2011 the OFCC held 23 community forum events and educated 915 individuals; From August 2011 to June 2012 there were 11 community forums educating 670 individuals. This report details each of those events, their date, location, purpose, and pertinent details to this report. In summary, as you see the Community Leader Forums have been very successful over the period of the grant with over 2,000 people being drawn to the forums. As always, we followed up the forums with a survey and the survey results were very positive in that the participants had a significant increase in knowledge and awareness of Fuel Cells and the Hydrogen Economy.