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Sample records for capillata medusae scyphozoa

  1. Variación lipídica en los ovocitos de la medusa Stomolophus meleagris (Scyphozoa: Rhizostomeae, durante el desarrollo gonádico, en la laguna Las Guásimas, Sonora, México

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    Liliana Carvalho-Saucedo

    2010-03-01

    Full Text Available La medusa S. meleagris, ha mostrado potencial de explotación pero hay escasa información sobre su biología reproductiva. El presente trabajo pretende conocer el contenido de los triglicéridos y fosfolípidos en los ovocitos durante el desarrollo gonadal, así como la proporción de sexos, talla de primera madurez y la concentración de proteínas y lípidos totales en la medusa. Se realizaron muestreos mensuales durante 2005 y 2006. A las medusas recolectadas en 2005, se les aplicó la técnica del sudán negro, para describir las características del ovocito y la cantidad triglicéridos y fosfolípidos y la técnica de hematoxilina-eosina para conocer el grado de desarrollo gonádico y la proporción de sexos. Las medusas del 2006 se emplearon para determinar la talla de primera madurez y el contenido de proteínas y lípidos totales. Se observaron cuatro fases de desarrollo en ambos sexos, con un desarrollo gamético continúo. El mayor porcentaje de organismos maduros se registró en abril. La proporción de sexos fue de 0.7:1.3. Se encontró mayor concentración de triglicéridos que de fosfolípidos en el citoplasma. Se obtuvo una correlación positiva entre triglicéridos y el diámetro del ovocito. La talla de primera madurez para ambos sexos fue de 105 mm. El mayor contenido de proteínas se obtuvo en abril y para lípidos en marzo.Lipid variation in oocytes of the jellyfish Stomolophus meleagris (Scyphozoa: Rhizostomeae from Las Guasimas Lagoon, Mexico, during gonadal development. The jellyfish Stomolophus meleagris has potential for commercial exploitation but there is little information on their reproductive biology. This paper seeks to evaluate some biochemical and demographic characteristics of the species. Samples were taken monthly during 2005 and 2006. Jellyfish collected in 2005 were used to describe the characteristics and quantity of oocyte triglycerides and phospholipids with the Sudan black technique, and to ascertain

  2. First record of the association between Lychnorhiza lucerna (Scyphozoa, Rhizostomeae and Cyrtograpsus affinis (Decapoda, Varunidae Primer registro de la asociación entre Lychnorhiza lucerna (Scyphozoa, Rhizostomeae y Cyrtograpsus affinis (Decapoda, Varunidae

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    Agustín Schiariti

    2012-11-01

    Full Text Available We report the association between the jellyfish Lychnorhiza lucerna and the crab Cyrtograpsus affinis. Numerous examples of associations between medusae and brachyurans have been observed in the field and noted in the literature. All of these cases involve medusae of the Class Scyphozoa and crabs belonging to the families Majidae and Portunidae. The presence of three individuals of C. affinis within the subgenital space of L. lucerna constitutes a striking finding since none species of this brachyuran family (Varunidae has been previously reported associated to scyphomedusae.Se reporta la asociación entre la medusa Lychnorhiza lucerna y el cangrejo Cyrtograpsus affinis. Existen numerosos ejemplos de asociaciones entre medusas y brachiuros mencionados en la literatura. Todos ellos involucran a las medusas de la Clase Scyphozoa y a cangrejos pertenecientes a las familias Majidae y Portunidae. La presencia de tres individuos de C. affinis dentro de la cavidad subgenital de L. lucerna es un hecho llamativo dado que, hasta el momento, no se habia reportado a ninguna especie de esta familia de brachiuros (Varunidae asociada con medusas de la Clase Scyphozoa.

  3. Medusae Fossae Formation

    Science.gov (United States)

    2002-01-01

    (Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust

  4. Radiation transport in MEDUSA

    International Nuclear Information System (INIS)

    Rose, S.J.; Evans, R.G.

    1983-09-01

    The transport of energy by X-ray photons has been included in the lD Lagrangian hydrodynamics code, MEDUSA. Calculations of the implosion by 0.53 μm laser irradiation of plastic and glass microballoons of current interest at the Central Laser Facility show that radiation preheats the fill gas and alters the temperature and density profiles during the implosion. A lower maximum gas temperature is obtained and this results, for a DT gas fill, in a greatly reduced neutron yield. (author)

  5. CT Demonstration of Caput Medusae

    Science.gov (United States)

    Weber, Edward C.; Vilensky, Joel A.

    2009-01-01

    Maximum intensity and volume rendered CT displays of caput medusae are provided to demonstrate both the anatomy and physiology of this portosystemic shunt associated with portal hypertension. (Contains 2 figures.)

  6. : Writing as medusa

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    Telma Scherer

    2016-12-01

    Full Text Available http://dx.doi.org/10.5007/2175-7917.2016v21n2p118 In this paper I’ll offer a personal reading of the short novel Água viva (medusa, or “living water”, in Portuguese from Clarice Lispector, through Helène Cixous statements about the creative process which she explains in her book Three steps in the ladder or writing. Cixous creates the image of a descendent ladder that has three steps: death, dreams and roots. Lispector does the same movement searching her “it”, and composes a radical practice with language that is also an investigation. In order to follow this path of the descendent ladder and analyze the “it” through comparative reading, I’ll bring some of Hilda Hilst’s poems, from her book Poemas malditos, gozozos e devotos and also Sylvia Plath’s, from Ariel, namely “Lady Lazarus”. Hilst constructs a game between obedience and subversion, faith and poetic creation, proposing a complexity of images from the idea of God, transfigured. Plath already brings to the reflection the cyclic recurrence, which is also a kind of all fear letting go. The readings of Hilst and Plath give light, in its own way, to the route undertaken in Cixous trail and enrich the search of the Lispector`s "it".

  7. Biomimetic autonomous robot inspired by the Cyanea capillata (Cyro)

    International Nuclear Information System (INIS)

    Villanueva, Alex A; Marut, Kenneth J; Michael, Tyler; Priya, Shashank

    2013-01-01

    A biomimetic robot inspired by Cyanea capillata, termed as ‘Cyro’, was developed to meet the functional demands of underwater surveillance in defense and civilian applications. The vehicle was designed to mimic the morphology and swimming mechanism of the natural counterpart. The body of the vehicle consists of a rigid support structure with linear DC motors which actuate eight mechanical arms. The mechanical arms in conjunction with artificial mesoglea create the hydrodynamic force required for propulsion. The full vehicle measures 170 cm in diameter and has a total mass of 76 kg. An analytical model of the mechanical arm kinematics was developed. The analytical and experimental bell kinematics were analyzed and compared to the C. capillata. Cyro was found to reach the water surface untethered and autonomously from a depth of 182 cm in five actuation cycles. It achieved an average velocity of 8.47 cm s −1  while consuming an average power of 70 W. A two-axis thrust stand was developed to calculate the thrust directly from a single bell segment yielding an average thrust of 27.9 N for the whole vehicle. Steady state velocity during Cyro's swimming test was not reached but the measured performance during its last swim cycle resulted in a cost of transport of 10.9 J (kg ⋅ m) −1  and total efficiency of 0.03. (paper)

  8. Compound complex enzymes and proteins of Stipa capillata from Semipalatinsk polygon

    International Nuclear Information System (INIS)

    Sarsenbaev, K.N.; Esnazarov, U.; Sarsenbaeva, M.V.; Seisebaev, A.

    2002-01-01

    The effects of low and high doses of irradiation near Semipalatinsk Atomic lake on the compound complex of different enzymes and proteins of leaves from different population of Stipa capillata are considered. 36 samples of Stipa capillata were analyzed by the iso-electrofocusing methods, native and SDS-electrophoresis. Levels of radioactivity effect on compound complex of peroxidase, esterase, acid phosphates and soluble proteins were found. SDS-PAGE and IEF methods did not show difference in peptides spectra between 36 populations of examined species. It means, that difference between contaminated and non-contaminated populations not so big as was expected. Compound complex soluble protein of Stipa capillata leaves changes under chronic doses of radioactivity. The difference in spectra between control and contaminated leaves make up 3-6 bands. Control leaves have more high molecular weight proteins than contaminated ones. Appearance of new bands is one of ways of plant adaptation. New components of enzymes spectra and soluble proteins were found. It was suggested, that gene mutation or post-translation modification of these proteins are result of chronic irradiation. To prove exactly genetic nature of this alteration aminoacids sequence for these proteins the DNA sequence of different Stipa capillata populations genomes were compared

  9. Como Perseu se defendeu de Medusa?

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    Rose Lumertz de Freitas

    2012-04-01

    Full Text Available Na psicanálise francesa, principalmente com Lacan, o conceito de falta passou a ser de grande importância. Ao que, então, perguntamos: o que é a falta? E quando esta falta? O que acontece? O que acontece quando o não especularizável não está excluído, se fazendo, assim, especular? Quando Perseu vai ao encontro de Medusa, guiando-se por sua imagem refletida em um espelho de bronze polido, segurado por Atena, como pôde este herói defender-se de Medusa? Qual foi a forma encontrada por ele para se defender da presença do objeto que introduz a dimensão do real nu?

  10. New equations of state for Medusa

    International Nuclear Information System (INIS)

    Bell, A.R.

    1980-12-01

    Three new options for the equation of state have been added to the Medusa computer simulation of laser-driven compression of matter. They are based on the Thomas-Fermi model of atomic structure. The first option is a set of analytic approximations to graphs of the Thomas-Fermi pressure and energy as functions of temperature and atomic volume prepared by Latter (Phys. Rev.; 99: 1854 (1955)). The second option includes quantum and exchange corrections to the degeneracy pressure and energy (Kirznitz. Sov. Phys. JETP; 8: 1081 (1959)) which model a condensed phase. The third option is a variation on the second option which allows the density of the condensed phase to be adjusted to agree with the measured value. (author)

  11. A study of medusae from Andaman and Nicobar waters

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    The results obtained from 14 cruises undertaken by FORV Sagar Sampada during the period 1986-1990 from Andaman and Nicobar waters are detailed. 346 zooplankton collections were made during this period and medusae were found from 307 stations. A...

  12. Caput medusae in alcoholic liver disease | Hari Kumar | Nigerian ...

    African Journals Online (AJOL)

    Caput medusae and palmar erythema are cardinal signs in cirrhosis of liver with portal hypertension. Palmar erythema is described more often as a marker for alcoholic etiology of chronic liver disease. The peripheral stigmata of chronic liver disease are not routinely seen now a days due to early diagnosis and better ...

  13. Cubozoa e Scyphozoa (Cnidaria: Medusozoa de águas costeiras do Brasil Cubozoa and Scyphozoa (Cnidaria: Medusozoa from Brazilian coastal waters

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    André C. Morandini

    2005-09-01

    Full Text Available As espécies de Cubozoa e Scyphozoa costeiras que ocorrem no Brasil são descritas, com base em espécimes de coleções de museus e exemplares recém-coletados. Chaves de identificação e um glossário também são apresentados. As espécies descritas são: Aurelia sp.; Cassiopea xamachana Bigelow, 1892; Chiropsalmus quadrumanus (Müller, 1859; Chrysaora lactea Eschscholtz, 1829; Drymonema dalmatinum Haeckel, 1880; Linuche unguiculata (Swartz, 1788; Lychnorhiza lucerna Haeckel, 1880; Nausithoe aurea Silveira & Morandini, 1997; Phyllorhiza punctata von Lendenfeld, 1884; Stomolophus meleagris Agassiz, 1862; Tamoya haplonema Müller, 1859 e Tripedalia cystophora Conant, 1897.Coastal species of Cubozoa and Scyphozoa occurring in Brazil are described, based on museum specimens and recently collected ones. Identification keys and a glossary are also presented. The listed species are: Aurelia sp.; Cassiopea xamachana Bigelow, 1892; Chiropsalmus quadrumanus (Müller, 1859; Chrysaora lactea Eschscholtz, 1829; Drymonema dalmatinum Haeckel, 1880; Linuche unguiculata (Swartz, 1788; Lychnorhiza lucerna Haeckel, 1880; Nausithoe aurea Silveira & Morandini, 1997; Phyllorhiza punctata von Lendenfeld, 1884; Stomolophus meleagris Agassiz, 1862; Tamoya haplonema Müller, 1859; and Tripedalia cystophora Conant, 1897.

  14. The Acute Toxicity and Hematological Characterization of the Effects of Tentacle-Only Extract from the Jellyfish Cyanea capillata

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    Liming Zhang

    2011-03-01

    Full Text Available To investigate the hematologic changes and the activities of jellyfish venoms other than hemolytic and cardiovascular toxicities, the acute toxicity of tentacle-only extract (TOE from the jellyfish Cyanea capillata was observed in mice, and hematological indexes were examined in rats. The median lethal dose (LD50 of TOE was 4.25 mg/kg, and the acute toxicity involved both heart- and nervous system-related symptoms. Arterial blood gas indexes, including pH, PCO2, HCO3−, HCO3std, TCO2, BEecf and BE (B, decreased significantly. PO2 showed a slight increase, while SO2c (% had no change at any time. Na+ and Ca2+ decreased, but K+ increased. Biochemical indexes, including LDH, CK, CK-MB, ALT, AST and sCr, significantly increased. Other biochemical indexes, including BUN and hemodiastase, remained normal. Lactic acid significantly increased, while glucose, Hct% and THbc showed slight temporary increases and then returned to normal. These results on the acute toxicity and hematological changes should improve our understanding of the in vivo pathophysiological effects of TOE from C. capillata and indicate that it may also have neurotoxicity, liver toxicity and muscular toxicity in addition to hemolytic and cardiovascular toxicities, but no kidney or pancreatic toxicity.

  15. Why is Taeniatherum caput-medusae (medusahead) Invasive in North America and not in its Native Eurasia?

    Science.gov (United States)

    Taeniatherum caput-medusae (medusahead) is an exotic annual grass introduced to North America in 1887 that has since invaded an estimated four million ha of rangelands. Contrary, in its native ranges of Eurasia, T. caput-medusae is not considered to be invasive. Why is it that T. caput-medusae expre...

  16. New combinations for two coronate polyp species (Atorellidae and Nausithoidae, Coronatae, Scyphozoa, Cnidaria)

    NARCIS (Netherlands)

    Morandini, A.C.; Jarms, G.

    2005-01-01

    Within the order Coronatae, six valid species remain known only by their polyp stage. The inability to relate them to any medusae genera of the group is a problem that remains to be solved in the order. With the examination of type specimens, we reassign the species Stephanoscyphistoma sibogae and

  17. Comparison of the PLCS malfunction event analyses by using the CESEC III and MEDUSA codes

    International Nuclear Information System (INIS)

    Oh, Myung Taek; Park, Chan Eok; Kim, Shin Whan; Seo, Jong Tae

    2004-01-01

    The MEDUSA is a code developed by Korea Power Engineering Company (KOPEC) for non-LOCA and LOCA analysis, providing two-fluid, three-field representation of two-phase flow. In this paper, as an effort to verify the MEDUSA code, comparative simulation for Pressurizer Level Control System (PLCS) malfunction with loss of off-site power is performed for UCN 3 and 4 plants. The results by the MEDUSA are compared with those calculated by the CESEC-III, a licensing analysis code used for Korean Standard Nuclear Power Plant (KSNP)

  18. Improvement of the MEDUSA code for one-dimensional laser fusion analysis (MEDUSA-P) and sensitivity analysis of the energy gain

    International Nuclear Information System (INIS)

    Takano, Hideki; Nakano, Ko.

    1976-07-01

    The MEDUSA-P code is a revised version of MEDUSA which was developed for calculation of the hydrodynamic behaviour (implosion process and thermonuclear reaction) of plasmas irradiated by an intense laser light. In conversion of MEDUSA for JAERI's computer, some programming errors were corrected. In order to express the violent space variation of plasmas, the number of region meshes is increased and the variables are expressed in double precision. And further, graphical representations of the main physical variables, i.e. rho (density), u (velocity), Tsub(i) (ion temperature), Tsub(e) (electron temperature) and P (pressure), are programmed to understand the complex time and space dependence of the plasma fluid with ease. The MEDUSA-P code is available for both computer FACOM 230/75 and CDC 6600. In this report, the calculations for spherical D-T pellets are performed with MEDUSA-P. The relation between several initial conditions and energy gain is described, and also phenomenology of the fuel implosion process. (auth.)

  19. Energy, Vacuum, Gas Fueling, and Security Systems for the Spherical Tokamak MEDUSA-CR

    Science.gov (United States)

    Gonzalez, Jeferson; Soto, Christian; Carvajal, Johan; Ribeiro, Celso

    2013-10-01

    The former spherical tokamak (ST) MEDUSA (Madison EDUcation Small Aspect.ratio tokamak, R security systems for MEDUSA-CR device. The interface with the control and data acquisition systems based on National Instruments (NI) software (LabView) and hardware (on loan to our laboratory via NI-Costa Rica) are also presented. VIE-ITCR, IAEA-CRP contract 17592, National Instruments of Costa Rica.

  20. Identification and activity of a lower eukaryotic serine proteinase inhibitor (serpin) from Cyanea capillata: analysis of a jellyfish serpin, jellypin.

    Science.gov (United States)

    Cole, Elisabeth B; Miller, David; Rometo, David; Greenberg, Robert M; Brömme, Dieter; Cataltepe, Sule; Pak, Stephen C; Mills, David R; Silverman, Gary A; Luke, Cliff J

    2004-09-21

    Delineating the phylogenetic relationships among members of a protein family can provide a high degree of insight into the evolution of domain structure and function relationships. To identify an early metazoan member of the high molecular weight serine proteinase inhibitor (serpin) superfamily, we initiated a cDNA library screen of the cnidarian, Cyanea capillata. We identified one serpin cDNA encoding for a full-length serpin, jellypin. Phylogenetic analysis using the deduced amino acid sequence showed that jellypin was most similar to the platyhelminthe Echinococcus multiocularis serpin and the clade P serpins, suggesting that this serpin evolved approximately 1000 million years ago (MYA). Modeling of jellypin showed that it contained all the functional elements of an inhibitory serpin. In vitro biochemical analysis confirmed that jellypin was an inhibitor of the S1 clan SA family of serine proteinases. Analysis of the interactions between the human serine proteinases, chymotrypsin, cathepsin G, and elastase, showed that jellypin inhibited these enzymes in the classical serpin manner, forming a SDS stable enzyme/inhibitor complex. These data suggest that the coevolution of serpin structure and inhibitory function date back to at least early metazoan evolution, approximately 1000 MYA.

  1. Comparative analysis of SLB for OPR1000 by using MEDUSA and CESEC-III codes

    International Nuclear Information System (INIS)

    Park, Jong Cheol; Park, Chan Eok; Kim, Shin Whan

    2005-01-01

    The MEDUSA is a system thermal hydraulics code developed by Korea Power Engineering Company (KOPEC) for Non-LOCA and LOCA analysis, using two fluid, three-field governing equations for two phase flow. The detailed descriptions for the MEDUSA code are given in Reference. A lot of effort is now being made to investigate the applicability of the MEDUSA code especially to Non-LOCA analysis, by comparing the analysis results with those from the current licensing code, CESEC-III: The comparative simulations of Pressurizer Level Control System(PLCS) Malfunction and Feedwater Line Break(FLB), which have been accomplished by C.E.Park and M.T.Oh, respectively, already showed that the MEDUSA code is applicable to the analysis of Non-LOCA events. In this paper, detailed thermal hydraulic analyses for Steam Line Break(SLB) without loss of off-site power were performed using the MEDUSA code. The calculation results were also compared with the CESEC-III, 1000(OPR1000), for the purpose of the code verification

  2. Thomas Albrecht, The Medusa Effect: Representation and Epistemology in Victorian Aesthetics

    OpenAIRE

    Sauvage, Julie

    2016-01-01

    Thomas Albrecht presents a stimulating study of what he calls the “Medusa effect” in Victorian aesthetics. This specific pattern, linked to the mythological figure of Medusa, raises both epistemological and aesthetic issues. The wide range of texts he examines spans a variety of genres and includes works by Gabriel Dante Rosetti, Freud, Nietzsche, Swinburne and Pater as well as George Eliot. They may not all be Victorian in the strict sense, but T. Albrecht does convincingly show that they al...

  3. First report of a thioredoxin homologue in jellyfish: molecular cloning, expression and antioxidant activity of CcTrx1 from Cyanea capillata.

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    Zengliang Ruan

    Full Text Available Thioredoxins (Trx proteins are a family of small, highly-conserved and ubiquitous proteins that play significant roles in the resistance of oxidative damage. In this study, a homologue of Trx was identified from the cDNA library of tentacle of the jellyfish Cyanea capillata and named CcTrx1. The full-length cDNA of CcTrx1 was 479 bp with a 312 bp open reading frame encoding 104 amino acids. Bioinformatics analysis revealed that the putative CcTrx1 protein harbored the evolutionarily-conserved Trx active site 31CGPC34 and shared a high similarity with Trx1 proteins from other organisms analyzed, indicating that CcTrx1 is a new member of Trx1 sub-family. CcTrx1 mRNA was found to be constitutively expressed in tentacle, umbrella, oral arm and gonad, indicating a general role of CcTrx1 protein in various physiological processes. The recombinant CcTrx1 (rCcTrx1 protein was expressed in Escherichia coli BL21 (DE3, and then purified by affinity chromatography. The rCcTrx1 protein was demonstrated to possess the expected redox activity in enzymatic analysis and protection against oxidative damage of supercoiled DNA. These results indicate that CcTrx1 may function as an important antioxidant in C. capillata. To our knowledge, this is the first Trx protein characterized from jellyfish species.

  4. Can Aurelia (Cnidaria, Scyphozoa species be differentiated by comparing their scyphistomae and ephyrae?

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    Maria Gambill

    2014-12-01

    Full Text Available Debate exists regarding the number of species of the moon jellyfish (genus Aurelia, a common member of the planktonic community of the coastal shelf seas around the world. Three Aurelia congeners (A. aurita, A. labiata and A. limbata are currently considered to exist but recent genetic analyses suggested that this is an oversimplification. We analyzed the morphological characteristics of scyphistomae, morphological characteristics of ephyrae and differences in the time span of the strobilation process of Aurelia congeners from 17, 7 and 6 different source populations, respectively, of known species. Morphological characteristics of scyphistomae were similar among the 17 populations but those of ephyrae, such as the shape and form of lappets, were effective discriminators in the 6 cases examined. We recommend identifying species based on differences in 1 the morphological characteristics of scyphistomae and ephyrae (and not only medusae, 2 the genetics of individuals, and 3 the geographical occurrence of the population. This study adds to the growing body of knowledge on scyphozoan scyphistomae and ephyrae, stages of the metagenic life cycle of scyphozoans that have received relatively little study compared to medusae.

  5. Studies on breeding shorebirds at Medusa Bay, Taimyr, in summer 2001

    NARCIS (Netherlands)

    Tulp, I.; Schekkerman, H.

    2001-01-01

    In the Summer of 2001 a combined Dutch-Russian expedition took place to the Willem Barentz field station at Medusa Bay near Dikson in north-western Taimyr. The expedition was organized by Alterra, the Working Group for International Waterbird and Wetland Research (WIWO) and the Agricultural

  6. The MEDUSA electron and ion spectrometer and the PIA ultraviolet photometers on Astrid-2

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    O. Norberg

    2001-06-01

    Full Text Available The miniature electron and ion spectrometer MEDUSA on Astrid-2 consists of two "top-hat"-type spherical electrostatic analyzers, sharing a common top-hat. Fast energy sweeps (16 electron sweeps and 8 ion sweeps per second allow for very high temporal resolution measurements of a two-dimensional slice of the particle distribution function. The energy range covered, is in the case of electrons, 4 eV to 22 keV and, in the case of ions, 2 eV to 12 keV. MEDUSA is mounted with its aperture close to the spin plane of Astrid-2, which allows for good pitch-angle coverage when the local magnetic field is in the satellite spin plane. The PIA-1/2 spin-scanning ultraviolet photometers measure auroral emissions. Using the spacecraft spin and orbital motion, it is possible to create two-dimensional images from the data. Spin-scanning photometers, such as PIA, are low-cost, low mass alternatives to auroral imagers, but place constraints on the satellite attitude. Data from MEDUSA are used to study processes in the auroral region, in particular, electrodynamics of aurora and "black aurora". MEDUSA is also a technological development, paving the way for highly capable, miniaturized particle spectrometers.Key words. Ionosphere (instruments and techniques – Magnetospheric physics (auroral phenomena; instruments and techniques

  7. Control and Data Acquisition for the Spherical Tokamak MEDUSA-CR

    Science.gov (United States)

    Soto, Christian; Gonzalez, Jeferson; Carvajal, Johan; Ribeiro, Celso

    2013-10-01

    The former spherical tokamak (ST) MEDUSA (Madison EDUcation Small Aspect.ratio tokamak, R loan to our laboratory via NI-Costa Rica. The interface with the energy, gas fueling, and security systems are also presented. VIE-ITCR, IAEA-CRP contract 17592, National Instruments of Costa Rica.

  8. Nausithoe aurea n. sp. (Scyphozoa: Coronatae: Nausithoidae), a species with two pathways of reproduction after strobilation: sexual and asexual

    NARCIS (Netherlands)

    Silveira, da Fábio Lang; Morandini, André Carrara

    1997-01-01

    Nausithoe aurea, a new species of scyphozoan Coronatae, is described from São Paulo State, Brazil. The solitary scyphistomae, with some zooxanthellae, strobilated producing planuloids and medusae; this represents an intermediate life cycle between that of metagenetic Nausithoidae and the submarine

  9. Reproduction of the giant jellyfish, Nemopilema nomurai (Scyphozoa: Rhizostomeae), in 2006-2008 as peripherally-transported populations

    Science.gov (United States)

    Iguchi, Naoki; Lee, Hye Eun; Yoon, Won Duk; Kim, Suam

    2010-06-01

    This study investigated the sexual maturation process, release of spermatozoa or eggs and oocyte diameter of the rhizostomid medusae Nemopilema nomurai using samples collected from August 2006 to June 2008 from the waters around Korea and Japan, including peripheral areas outside the species’ usual habitat. Immature medusae were observed from June to October only in the western sector of the study area. The onset of spermatozoa and egg release occurred in September and October, respectively, and peaked in December and January. Medusae migrated eastward from source areas with the Tsushima Warm Current, where they formed gametes and spawned. Peak position and maximum oocyte diameter increased as the gonads developed according to the size-frequency distribution of oocytes. No fertilized eggs or embryos were found in the gonads. The correlation was analyzed with bell diameter, maximum oocyte diameter, sampling date, surface water temperature and gonad color to estimate which environmental factors and maturation indices were related to the maturation stage of females. Maturation stage correlated well with maximum oocyte diameter, which correlated negatively with surface water temperature. There was no significant correlation between bell diameter and maturation stage. Therefore, bell diameter was inappropriate for determining maturation index. Sex could not be distinguished clearly by gonad color. However, light pink gonads were more prevalent in males and various deep colors such as orange and brown were more frequent in female medusae.

  10. β adrenergic receptor/cAMP/PKA signaling contributes to the intracellular Ca2+ release by tentacle extract from the jellyfish Cyanea capillata.

    Science.gov (United States)

    Wang, Qianqian; Zhang, Hui; Wang, Bo; Wang, Chao; Xiao, Liang; Zhang, Liming

    2017-07-25

    Intracellular Ca 2+ overload induced by extracellular Ca 2+ entry has previously been confirmed to be an important mechanism for the cardiotoxicity as well as the acute heart dysfunction induced by jellyfish venom, while the underlying mechanism remains to be elucidated. Under extracellular Ca 2+ -free or Ca 2+ -containing conditions, the Ca 2+ fluorescence in isolated adult mouse cardiomyocytes pre-incubated with tentacle extract (TE) from the jellyfish Cyanea capillata and β blockers was scanned by laser scanning confocal microscope. Then, the cyclic adenosine monophosphate (cAMP) concentration and protein kinase A (PKA) activity in primary neonatal rat ventricular cardiomyocytes were determined by ELISA assay. Furthermore, the effect of propranolol against the cardiotoxicity of TE was evaluated in Langendorff-perfused rat hearts and intact rats. The increase of intracellular Ca 2+ fluorescence signal by TE was significantly attenuated and delayed when the extracellular Ca 2+ was removed. The β adrenergic blockers, including propranolol, atenolol and esmolol, partially inhibited the increase of intracellular Ca 2+ in the presence of 1.8 mM extracellular Ca 2+ and completely abolished the Ca 2+ increase under an extracellular Ca 2+ -free condition. Both cAMP concentration and PKA activity were stimulated by TE, and were inhibited by the β adrenergic blockers. Cardiomyocyte toxicity of TE was antagonized by β adrenergic blockers and the PKA inhibitor H89. Finally, the acute heart dysfuction by TE was antagonized by propranolol in Langendorff-perfused rat hearts and intact rats. Our findings indicate that β adrenergic receptor/cAMP/PKA signaling contributes to the intracellular Ca 2+ overload through intracellular Ca 2+ release by TE from the jellyfish C. capillata.

  11. Isoindolinone-containing meroterpenoids with α-glucosidase inhibitory activity from mushroom Hericium caput-medusae.

    Science.gov (United States)

    Chen, Lin; Li, Zheng-Hui; Yao, Jian-Neng; Peng, Yue-Ling; Huang, Rong; Feng, Tao; Liu, Ji-Kai

    2017-10-01

    Hericium caput-medusae is an edible and medicinal mushroom closely relative to H. erinaceus. According to our detailed chemical investigation, two novel isoindolinone-containing meroterpene dimers, caputmedusins A (1) and B (2), as well as nine analogues, caputmedusins C-K (3-11), were isolated from the fermentation broth of H. caput-medusae. Their structures were elucidated by analyses of 1D and 2D NMR spectroscopic methods. The absolute configurations of 1-4 were speculated based on the specific optical rotation and biogenetic consideration. The absolute configurations of 10 and 11 were rationalized by the calculation of 1 H NMR chemical shifts. Caputmedusins A-C (1-3) showed moderate inhibitory activity against α-glucosidase with the IC 50 values of 39.2, 36.2 and 40.8μM, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Interannual variation in the composition of the assemblages of medusae and ctenophores in St. Helena Bay, Southern Benguela Ecosystem

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    Emmanuelle Buecher

    2000-12-01

    Full Text Available The assemblages of medusae and ctenophores were examined from samples collected each winter from St Helena Bay, over the 10-year period 1988-1997. A total of 50 hydromedusae, 1 scyphozoan and 2 ctenophore species were identified from 243 samples. Although the data set is characterised by great interannual variability, two main assemblages could be identified each year. These were characterised by either holoplanktonic medusae (e.g. Liriope tetraphylla, Aglaura hemistoma or meroplanktonic medusae (e.g. Mitrocomella millardae, Chrysaora hysoscella and ctenophores (e.g. Pleurobrachia pileus. The holoplanktonic medusae were typical of samples at the southern edge of the Bay, and were positively associated with both depth and temperature. Their abundances tended to increase during warm years (1992, 1993 and 1997 as warm surface water flooded the Bay. The meroplanktonic medusae and ctenophores were typical of samples collected within the Bay, and the density of species tended to be negatively correlated with temperature and depth. In spite of the eurythermal nature of the meroplanktonic species, they were more common during cold years (1990 and 1995. This paper represents the first Bay-wide, interannual study of any zooplankton group, and contributes important base line information on the structure of regional pelagic assemblages.

  13. Picadura de medusa Olindias sambaquiensis: Análisis de 49 casos

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    Juan H Mosovich

    2012-10-01

    Full Text Available La picadura de la medusa o agua viva Olindia sambaquiensis es de ocurrencia frecuente en las playas de la costa de la provincia de Buenos Aires. Se notifican entre quinientas y mil picaduras de medusas por temporada en la localidad balnearia de Monte Hermoso, al sur de la provincia de Buenos Aires. El daño cutáneo que provoca por su elevada acción urticante plantea un serio inconveniente para el desarrollo del turismo. Durante el mes de enero de 1998, en la localidad de Monte Hermoso se reunieron un total de 49 casos que fueron examinados dentro de la hora posterior a la picadura. Veintiocho eran de sexo masculino (57.1%. La edad promedio fue de 16 ± 4.1 (rango 5-80. El 54% presentó lesiones eritemato-edematosas de configuración lineal, el 28% presentó lesiones predominantemente eritematosas y el 18% presentó placas eritemato-edematosas. En el 73% de los casos las lesiones se localizaron en miembros inferiores. Hemos redefinido la lesión cutánea producida por la medusa O. sambaquiensis, su evolución, sus dimensiones y localizaciones más frecuentes. Además, se ha tipificado y cuantificado el dolor que produce, y otros signos y síntomas que acompañan a la picadura en la hora posterior, a las primeras 24 horas y a los 30 días. Describimos las conductas terapéuticas utilizadas en nuestra costa, evaluamos la efectividad de algunas de ellas en el control del dolor y finalmente proponemos un esquema terapéutico para dicha picadura.

  14. Trophic Cascading of Medusae on the Relationships between Copepods and Diatoms in a Subtropical Coastal Ecosystem

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    Jia-Lu Chung

    2009-01-01

    Full Text Available To investigate the spatial and temporal variation of phytoplankton and copepods, eight seasonal cruises (January 2005 ~ Oc to ber 2006 were conducted in a subtropical coast site that encom passed 19 sampling stations. The results in dicated that the temperature (18.4 - 29.7°C varied more than 10°C seasonally, while nutrient concentrations (ni trate: 0.4 - 6.3 mM, phosphate: 0.1 - 0.8 mM, and silicate 2.1 - 12.1 mM were in versely corre lated with temperature. Diatoms (2792 - 1602437 cells m-3 constituted > 90% of the phytoplankton as semblages and dinoflagellates (226 - 10029 cells m-3 represented only ~10% of the algaebiomass. Copepod abun dance (8 - 1031 ind. m-3 varied positively with that of diatom and tempeature. Therelative abundance of Temora spp. (1 - 712 ind. m-3 varied from 69% in summer; that of Paracalanus spp. (0.1 - 176 ind. m-3 were > 25% in spring and au tumn and Calanus spp. (0.5 - 24 ind. m-3 dom i nated in win ter and spring, but ac counted for only ~10% of the to tal copepods. Both di a tom den sity and copepod abun dance were positively correlated with temperature, indicating these two plank tongroups were left bot tom-up control. The copepod abun dance positively co-aried with diatoms in 2005, but not in 2006. Fur ther sea son-to-sea son analysis showed that the diatomvs. copepodratios changed positively only when the medusa abun dance changed greatly (> 40-fold between consecutive sea sons. During periods when the medusa abundance varied less than 10-fold between seasons, there is no relationship between the ratios and the medusa abun dance. This study suggests that the stability of the medusa abundance from season to season could be important in regulating the ecological linkage between diatoms and their predators ¡V copepods.

  15. Medusa structure of the gene regulatory network: dominance of transcription factors in cancer subtype classification.

    Science.gov (United States)

    Guo, Yuchun; Feng, Ying; Trivedi, Niraj S; Huang, Sui

    2011-05-01

    Gene expression profiles consisting of ten thousands of transcripts are used for clustering of tissue, such as tumors, into subtypes, often without considering the underlying reason that the distinct patterns of expression arise because of constraints in the realization of gene expression profiles imposed by the gene regulatory network. The topology of this network has been suggested to consist of a regulatory core of genes represented most prominently by transcription factors (TFs) and microRNAs, that influence the expression of other genes, and of a periphery of 'enslaved' effector genes that are regulated but not regulating. This 'medusa' architecture implies that the core genes are much stronger determinants of the realized gene expression profiles. To test this hypothesis, we examined the clustering of gene expression profiles into known tumor types to quantitatively demonstrate that TFs, and even more pronounced, microRNAs, are much stronger discriminators of tumor type specific gene expression patterns than a same number of randomly selected or metabolic genes. These findings lend support to the hypothesis of a medusa architecture and of the canalizing nature of regulation by microRNAs. They also reveal the degree of freedom for the expression of peripheral genes that are less stringently associated with a tissue type specific global gene expression profile.

  16. The hydroid and medusa of Sarsia bella sp. nov. (Hydrozoa, Anthoathecatae, Corynidae, with a correction of the life cycle of Polyorchis penicillatus (Eschscholtz

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    Anita Brinckmann-Voss

    2000-12-01

    Full Text Available A new hydrozoan, Sarsia bella sp. nov. is described in both its hydroid and medusa stage from north of Puget Sound, Washington in the San Juan Islands, USA and off the southernmost tip of Vancouver Island, Canada. The medusa is distinguished from other Sarsia species by 16 exumbrellar nematocyst patches and in being more transparent or glass like when living than any other known species of the genus. The exumbrellar nematocyst patches become indistinct in mature specimens and in those crowded in culture, with single nematocysts increasingly spaced out. The hydroid, both field-collected and raised in culture from its medusa, forms small, upright stolonal colonies not more than 1.5 mm high. The hydranths bear an oral whorl of four to five capitate tentacles, and immediately below a second whorl of slightly shorter capitate tentacles. In thriving colonies there is occasionally a whorl of small filiform tentacles on the lower part of the hydranth. Medusa buds develop in the middle of hydranth below the capitate tentacles and above the reduced filiform tentacles, if present. Young medusae are liberated with the typical 16 exumbrellar nematocyst patches. The hydroid of this species was originally mistaken for the hydroid of Polyorchis penicillatus. Brinckmann-Voss (1977 reported a small corynid hydroid living on the margin of rock scallop shells. Medusae liberated from this hydroid were at that time believed to be those of Polyorchis penicillatus (Eschscholtz present in the plankton. Immature medusae of these two species appear strikingly similar, especially with regard to their exumbrellar nematocyst patches, four tentacles and abaxial ocelli. Since then however, this connection has been proven wrong, because an identical hydroid was raised from the medusae of the new species Sarsia bella. Second generation medusae raised in the laboratory were carefully compared with medusae liberated from field collected hydroids (thought to have been Polyorchis

  17. Picadura de medusa Olindias sambaquiensis: Análisis de 49 casos

    Directory of Open Access Journals (Sweden)

    Juan H Mosovich

    2012-10-01

    Full Text Available La picadura de la medusa o agua viva Olindia sambaquiensis es de ocurrencia frecuente en las playas de la costa de la provincia de Buenos Aires. Se notifican entre quinientas y mil picaduras de medusas por temporada en la localidad balnearia de Monte Hermoso, al sur de la provincia de Buenos Aires. El daño cutáneo que provoca por su elevada acción urticante plantea un serio inconveniente para el desarrollo del turismo. Durante el mes de enero de 1998, en la localidad de Monte Hermoso se reunieron un total de 49 casos que fueron examinados dentro de la hora posterior a la picadura. Veintiocho eran de sexo masculino (57.1%. La edad promedio fue de 16 ± 4.1 (rango 5-80. El 54% presentó lesiones eritemato-edematosas de configuración lineal, el 28% presentó lesiones predominantemente eritematosas y el 18% presentó placas eritemato-edematosas. En el 73% de los casos las lesiones se localizaron en miembros inferiores. Hemos redefinido la lesión cutánea producida por la medusa O. sambaquiensis, su evolución, sus dimensiones y localizaciones más frecuentes. Además, se ha tipificado y cuantificado el dolor que produce, y otros signos y síntomas que acompañan a la picadura en la hora posterior, a las primeras 24 horas y a los 30 días. Describimos las conductas terapéuticas utilizadas en nuestra costa, evaluamos la efectividad de algunas de ellas en el control del dolor y finalmente proponemos un esquema terapéutico para dicha picadura.Olindias sambaquiensis jellyfish sting occurs frequently in Buenos Aires province coast beaches. Among five hundred and one thousand stings by jellyfish are reported each season at Monte Hermoso, a beach village in the South of Buenos Aires province. The skin damage provoked because of its highly irritant effect poses a serious issue related to tourism development. A total number of 49 cases that were examined during the first hour after the sting were enrolled in Monte Hermoso during January 1998. Twenty

  18. [Spectral characteristics of dissolved organic matter released during the metabolic process of small medusa].

    Science.gov (United States)

    Guo, Dong-Hui; Yi, Yue-Yuan; Zhao, Lei; Guo, Wei-Dong

    2012-06-01

    The metabolic processes of jellyfish can produce dissolved organic matter (DOM) which will influence the functioning of the aquatic ecosystems, yet the optical properties of DOM released by jellyfish are unknown. Here we report the absorption and fluorescence properties of DOM released by a medusa species Black fordia virginica during a 24 h incubation experiment. Compared with the control group, an obvious increase in the concentrations of dissolved organic carbon (DOC), absorption coefficient (a280) and total dissolved nitrogen (TDN) was observed in incubation group. This clearly demonstrated the release of DOM, chromophoric DOM (CDOM) and dissolved nutrients by B. virginica which feed on enough of Artemia sp. before the experiment. The increase in spectral slope ratio (SR) and decrease in humification index (HIX) indicated that the released DOM was less-humified and had relatively lower molecular weight. Parallel factor analysis (PARAFAC) decomposed the fluorescence matrices of DOM into three humic-like components (C1-C3) and one protein-like component (C4). The Fmax of two components (C2: 400 nm showed little changes. Thus, we suggested a zooplankton index (ZIX) to trace and characterize the DOM excreted by metabolic activity of zooplankton, which is calculated as the ratio of the sum of Fmax of all fluorescence components with the emission wavelength 400 nm.

  19. MEDUSA: The ExoMars experiment for in-situ monitoring of dust and water vapour

    Science.gov (United States)

    Colangeli, L.; Lopez-Moreno, J. J.; Nørnberg, P.; Della Corte, V.; Esposito, F.; Mazzotta Epifani, E.; Merrison, J.; Molfese, C.; Palumbo, P.; Rodriguez-Gomez, J. F.; Rotundi, A.; Visconti, G.; Zarnecki, J. C.; The International Medusa Team

    2009-07-01

    Dust and water vapour are fundamental components of the Martian atmosphere. In view of tracing the past environmental conditions on Mars, that possibly favoured the appearing of life forms, it is important to study the present climate and its evolution. Here dust and water vapour have (and have had) strong influence. Of major scientific interest is the quantity and physical, chemical and electrical properties of dust and the abundance of water vapour dispersed in the atmosphere and their exchange with the surface. Moreover, in view of the exploration of the planet with automated systems and in the future by manned missions, it is of primary importance to analyse the hazards linked to these environmental factors. The Martian Environmental Dust Systematic Analyser (MEDUSA) experiment, included in the scientific payload of the ESA ExoMars mission, accommodates a complement of sensors, based on optical detection and cumulative mass deposition, that aims to study dust and water vapour in the lower Martian atmosphere. The goals are to study, for the first time, in-situ and quantitatively, physical properties of the airborne dust, including the cumulative dust mass flux, the dust deposition rate, the physical and electrification properties, the size distribution of sampled particles and the atmospheric water vapour abundance versus time.

  20. Plant-pathogen interactions: leaf physiology alterations in poplars infected with rust (Melampsora medusae).

    Science.gov (United States)

    Gortari, Fermín; Guiamet, Juan José; Graciano, Corina

    2018-01-23

    Rust produced by Melampsora sp. is considered one of the most relevant diseases in poplar plantations. Growth reduction in poplar plantations takes place because rust, like other pathogens, alters leaf physiology. There is not a complete evaluation of several of the physiological traits that can be affected by rust at leaf level. Therefore, the aim of this work was to evaluate, in an integrative way and in the same pathosystem, which physiological processes are affected when Populus deltoides Bartr. ex Marsh. leaves are infected by rust (Melampsora medusae Thümen). Leaves of two clones with different susceptibility to rust were analyzed. Field and pot experiments were performed, and several physiological traits were measured in healthy and infected leaves. We conclude that rust affects leaf mesophyll integrity, and so water movement in the leaf in liquid phase is affected. As a consequence, gas exchange is reduced, affecting both carbon fixation and transpiration. However, there is an increase in respiration rate, probably due to plant and fungal respiration. The increase in respiration rate is important in the reduction of net photosynthetic rate, but also some damage in the photosynthetic apparatus limits leaf capacity to fix carbon. The decrease in chlorophyll content would start later and seems not to explain the reduction in net photosynthetic rate. Both clones, although they have different susceptibility to rust, are affected in the same physiological mechanisms. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Shallow radar (SHARAD) sounding observations of the Medusae Fossae Formation, Mars

    Science.gov (United States)

    Carter, L.M.; Campbell, B.A.; Watters, T.R.; Phillips, R.J.; Putzig, N.E.; Safaeinili, A.; Plaut, J.J.; Okubo, C.H.; Egan, A.F.; Seu, R.; Biccari, D.; Orosei, R.

    2009-01-01

    The SHARAD (shallow radar) sounding radar on the Mars Reconnaissance Orbiter detects subsurface reflections in the eastern and western parts of the Medusae Fossae Formation (MFF). The radar waves penetrate up to 580 m of the MFF and detect clear subsurface interfaces in two locations: west MFF between 150 and 155?? E and east MFF between 209 and 213?? E. Analysis of SHARAD radargrams suggests that the real part of the permittivity is ???3.0, which falls within the range of permittivity values inferred from MARSIS data for thicker parts of the MFF. The SHARAD data cannot uniquely determine the composition of the MFF material, but the low permittivity implies that the upper few hundred meters of the MFF material has a high porosity. One possibility is that the MFF is comprised of low-density welded or interlocked pyroclastic deposits that are capable of sustaining the steep-sided yardangs and ridges seen in imagery. The SHARAD surface echo power across the MFF is low relative to typical martian plains, and completely disappears in parts of the east MFF that correspond to the radar-dark Stealth region. These areas are extremely rough at centimeter to meter scales, and the lack of echo power is most likely due to a combination of surface roughness and a low near-surface permittivity that reduces the echo strength from any locally flat regions. There is also no radar evidence for internal layering in any of the SHARAD data for the MFF, despite the fact that tens-of-meters scale layering is apparent in infrared and visible wavelength images of nearby areas. These interfaces may not be detected in SHARAD data if their permittivity contrasts are low, or if the layers are discontinuous. The lack of closely spaced internal radar reflectors suggests that the MFF is not an equatorial analog to the current martian polar deposits, which show clear evidence of multiple internal layers in SHARAD data. ?? 2008 Elsevier Inc.

  2. Medusa: una aplicación de la integración entre PDF y ASP:NET®

    Directory of Open Access Journals (Sweden)

    CARLOS M. ZAPATA J.

    2005-01-01

    Full Text Available El formato de Documentos Portátiles (PDF por sus siglas en inglés se ha venido consolidando en el mundo como un estándar para la transmisión de documentos vía Web, especialmente reconocidos como sólo lectura. Sin embargo, poco se han trabajado las capacidades interactivas de dicha tecnología, en particular para la captura y transmisión de datos a un servidor. En este artículo se presenta MEDUSA, un software basado en tecnología PDF que interactúa con ASP® y ASP.NET® para el manejo de una plataforma de compras vía Web.

  3. The Medusa Multi-Coil Versus Alternative Vascular Plugs for Iliac Artery Aneurysm Embolization (MVP-EMBO) Study.

    Science.gov (United States)

    George, Jon C; Varghese, Vincent; Kovach, Richard

    2016-01-01

    Transcatheter embolization has evolved from the use of autologous clot as the embolic agent, to stainless-steel coils, to braided-nitinol vascular plugs. However, there are disadvantages to platinum and metal coils, including procedural time, radiation exposure, mass effect, risk of distal embolization, recanalization, imaging artifacts, and cost. Therefore, a large vessel-occluding device is needed to mitigate these current disadvantages. The Medusa Multi-Coil (MMC; EndoShape, Inc) is a Food and Drug Administration (FDA)-approved embolization device constructed primarily of radioopaque coils with synthetic fibers to promote thrombogenicity, and a unique delivery platform with both proximal and distal attachment to assist with precise placement. We report our experience with the endovascular treatment of internal iliac artery aneurysms using platinum coils vs MMCs.

  4. MEDUSA-2.0: an intermediate complexity biogeochemical model of the marine carbon cycle for climate change and ocean acidification studies

    Directory of Open Access Journals (Sweden)

    A. Yool

    2013-10-01

    Full Text Available MEDUSA-1.0 (Model of Ecosystem Dynamics, nutrient Utilisation, Sequestration and Acidification was developed as an "intermediate complexity" plankton ecosystem model to study the biogeochemical response, and especially that of the so-called "biological pump", to anthropogenically driven change in the World Ocean (Yool et al., 2011. The base currency in this model was nitrogen from which fluxes of organic carbon, including export to the deep ocean, were calculated by invoking fixed C:N ratios in phytoplankton, zooplankton and detritus. However, due to anthropogenic activity, the atmospheric concentration of carbon dioxide (CO2 has significantly increased above its natural, inter-glacial background. As such, simulating and predicting the carbon cycle in the ocean in its entirety, including ventilation of CO2 with the atmosphere and the resulting impact of ocean acidification on marine ecosystems, requires that both organic and inorganic carbon be afforded a more complete representation in the model specification. Here, we introduce MEDUSA-2.0, an expanded successor model which includes additional state variables for dissolved inorganic carbon, alkalinity, dissolved oxygen and detritus carbon (permitting variable C:N in exported organic matter, as well as a simple benthic formulation and extended parameterizations of phytoplankton growth, calcification and detritus remineralisation. A full description of MEDUSA-2.0, including its additional functionality, is provided and a multi-decadal spin-up simulation (1860–2005 is performed. The biogeochemical performance of the model is evaluated using a diverse range of observational data, and MEDUSA-2.0 is assessed relative to comparable models using output from the Coupled Model Intercomparison Project (CMIP5.

  5. Understanding Aggregation and Estimating Seasonal Abundance of Chrysaora quinquecirrha Medusae from a Fixed-station Time Series in the Choptank River, Chesapeake Bay

    Science.gov (United States)

    Tay, J.; Hood, R. R.

    2016-02-01

    Although jellyfish exert strong control over marine plankton dynamics (Richardson et al. 2009, Robison et al. 2014) and negatively impact human commercial and recreational activities (Purcell et al. 2007, Purcell 2012), jellyfish biomass is not well quantified due primarily to sampling difficulties with plankton nets or fisheries trawls (Haddock 2004). As a result, some of the longest records of jellyfish are visual shore-based surveys, such as the fixed-station time series of Chrysaora quinquecirrha that began in 1960 in the Patuxent River in Chesapeake Bay, USA (Cargo and King 1990). Time series counts from fixed-station surveys capture two signals: 1) demographic change at timescales on the order of reproductive processes and 2) spatial patchiness at shorter timescales as different parcels of water move in and out of the survey area by tidal and estuarine advection and turbulent mixing (Lee and McAlice 1979). In this study, our goal was to separate these two signals using a 4-year time series of C. quinquecirrha medusa counts from a fixed-station in the Choptank River, Chesapeake Bay. Idealized modeling of tidal and estuarine advection was used to conceptualize the sampling scheme. Change point and time series analysis was used to detect demographic changes. Indices of aggregation (Negative Binomial coefficient, Taylor's Power Law coefficient, and Morisita's Index) were calculated to describe the spatial patchiness of the medusae. Abundance estimates revealed a bloom cycle that differed in duration and magnitude for each of the study years. Indices of aggregation indicated that medusae were aggregated and that patches grew in the number of individuals, and likely in size, as abundance increased. Further inference from the conceptual modeling suggested that medusae patch structure was generally homogenous over the tidal extent. This study highlights the benefits of using fixed-station shore-based surveys for understanding the biology and ecology of jellyfish.

  6. A Medusa e o gozo: uma leitura da diferença sexual em psicanálise

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    Maria Cristina Poli

    2007-12-01

    Full Text Available Pretende-se retomar, nas obras de Freud e Lacan, algumas das principais balizas do estatuto da diferença sexual em psicanálise. O enigma feminino, assinalado por Freud, e as diferentes formas de gozo, referidas por Lacan, situam o registro da referida diferença. Por fim, algumas contribuições de Foucault nos permitem avaliar a implicação política da psicanálise em relação a esse tema.The Medusa and the joy: a reading of the sexual difference in psychoanalysis. This article revisits the texts of Freud and Lacan, indicating some of the main beacons of the statute of the sexual difference in psychoanalysis. The feminine enigma, designated from Freud, and the different forms of joy, related from Lacan, point out the register of the sexual difference in psychoanalysis. Some contributions of Foucault allow for the politic implication of the psychoanalysis in relation to this subject.

  7. Interannual variability, growth, reproduction and feeding of Pelagia noctiluca (Cnidaria: Scyphozoa) in the Straits of Messina (Central Mediterranean Sea): Linkages with temperature and diet

    Science.gov (United States)

    Rosa, S.; Pansera, M.; Granata, A.; Guglielmo, L.

    2013-02-01

    To identify some of the possible environmental factors stimulating the increasingly frequent outbreaks of the scyphomedusa Pelagia noctiluca in the Straits of Messina, we investigated its abundance, growth, reproduction and feeding over a 4-year period, from 2007 to 2011, at two coastal sites. Using either field investigations and manipulative experiments we show that, among the various factors considered, shifts in water temperature (influencing medusae metabolism, growth and reproduction rates) and the size structure of the zooplankton community (their natural preys) can promote the proliferation of P. noctiluca. In particular, we show that increased temperature let jellyfishes to grow more rapidly and reach exceptional sizes. We also report a peculiar opportunistic behavior of P. noctiluca, which makes this species a potentially strong competitor in the pelagic trophic web of the Straits ecosystem. We therefore propose that more frequent P. noctiluca outbreaks stimulated by increasing sea surface temperature and shifts in their prey availability and composition would become, in the near future, a major cause of ecosystem shift.

  8. On the occurrence of Obelia medusa blooms and empirical evidence of unusual massive accumulations of Obelia and Amphisbetia hydroids on the Argentina shoreline Bloom de la medusa Obelia y evidencia empírica de una inusual acumulación masiva de hidroides de Obelia y Amphisbetia en la línea de costa en Argentina

    Directory of Open Access Journals (Sweden)

    Gabriel Genzano

    2008-01-01

    Full Text Available Medusa blooms are a scarcely known phenomenon. For temperate, southwestern Atlantic waters, reports of such events are almost nonexistent. This research reports the analysis of a total of 1043 plankton samples taken from 1993 to 2006 and benthic samples collected by seasonal SCUBA diving since 1997 along the Buenos Aires coast. The medusa Obelia longissima was observed in very low densities and frequen-cies, except in October 2003, when a bloom of this species was detected. Soon afterward, two consecutive massive accumulations of O. longissima and Amphisbetia operculata colonies were detected on the coast by the mhabitants of Mar del Plata (38°00'S-57°32'W and the coastal Mar Chiquita Lagoon (37°32'S-57°19'W between March and April 2004. The colonies of both species were collected from the shoreline at low tide at both sites. The environmental factors of that period seemed to be particularly appropriate for promoting optimum growth conditions for these hydroid species. This paper reports and describes the mentioned abnormal phe-nomena, providing baseline information on these little-understood events.Los blooms de medusas son un fenómeno escasamente conocido. En las aguas templadas del Atlántico sudoccidental, esta clase de eventos son casi inexistentes. Un total de 1.043 muestras de plancton de 1993 a 2006 fueron analizadas como también aquellas de bentos colectadas por SCUBA estacionalmente desde 1997 en la costa de Buenos Aires. Para la medusa Obelia longissima fueron observadas muy bajas densidades y frecuencias, con excepción de octubre de 2003 cuando un bloom de esta medusa fue detectado. Seguidamente, dos acumulaciones masivas consecutivas de colonias de O. longissima y de Amphisbetia operculata fueron detectadas sobre la línea de costa por habitantes de Mar del Plata (38°00'S-57°32'W y de la laguna costera Mar Chiquita (37°32'S-57°19'W entre marzo y abril del 2004. Las colonias de ambas especies fueron colectadas desde la l

  9. Molecular characterization and prevalence of two capulaviruses: Alfalfa leaf curl virus from France and Euphorbia caput-medusae latent virus from South Africa.

    Science.gov (United States)

    Bernardo, Pauline; Muhire, Brejnev; François, Sarah; Deshoux, Maëlle; Hartnady, Penelope; Farkas, Kata; Kraberger, Simona; Filloux, Denis; Fernandez, Emmanuel; Galzi, Serge; Ferdinand, Romain; Granier, Martine; Marais, Armelle; Monge Blasco, Pablo; Candresse, Thierry; Escriu, Fernando; Varsani, Arvind; Harkins, Gordon W; Martin, Darren P; Roumagnac, Philippe

    2016-06-01

    Little is known about the prevalence, diversity, evolutionary processes, genomic structures and population dynamics of viruses in the divergent geminivirus lineage known as the capulaviruses. We determined and analyzed full genome sequences of 13 Euphorbia caput-medusae latent virus (EcmLV) and 26 Alfalfa leaf curl virus (ALCV) isolates, and partial genome sequences of 23 EcmLV and 37 ALCV isolates. While EcmLV was asymptomatic in uncultivated southern African Euphorbia caput-medusae, severe alfalfa disease symptoms were associated with ALCV in southern France. The prevalence of both viruses exceeded 10% in their respective hosts. Besides using patterns of detectable negative selection to identify ORFs that are probably functionally expressed, we show that ALCV and EcmLV both display evidence of inter-species recombination and biologically functional genomic secondary structures. Finally, we show that whereas the EcmLV populations likely experience restricted geographical dispersion, ALCV is probably freely moving across the French Mediterranean region. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Mapping Variability in the Medusae Fossae Formation: Yardang Morphologies, Fluvial Reworking, and Crater Depth to Diameter Ratios

    Science.gov (United States)

    Khuller, A. R.; Kerber, L.

    2017-12-01

    The Medusae Fossae Formation (MFF) is a voluminous, fine-grained deposit thought to be of pyroclastic origin. While it contains widespread, well-preserved inverted fluvial features, its pervasive cover of dust means that little is known about its composition, and indirect means must be used to characterize its material properties. This project aims to correlate fluvial features in the Western MFF with other indicators of material strength: yardang morphology and crater depth-to-diameter ratios. For this work, Context Camera (CTX) images were used to map features of fluvial origin (inverted channels, sinuous ridges, alluvial fans). The presence of rounded, meso-yardangs in close proximity to fluvial features was also mapped. Crater depth-diameter (d/D) ratios (for craters 1-512km) were analyzed using a global Mars crater database (Robbins and Hynek, 2012) as a proxy for material strength. Approximately 1400 fluvial segments were mapped, with the most populous cluster located in Aeolis and Zephyria Plana. Rounded meso-yardangs were found to be common in areas that also have fluvial features. In agreement with previous work (Barlow, 1993), MFF craters were found to have a greater d/D ratio (0.0523) than the global mean (0.0511). Ratios between MFF lobes differ significantly, providing insight into the heterogeneity of induration within the formation. The deepest craters are found in Eumenides Dorsum and the shallowest in Aeolis Planum, consistent with a greater degree of induration and reworking in the western part of the formation where the fluvial features and "salt-playa" meso-yardangs are found. It also suggests that Eumenides, which is the tallest MFF outcrop, could also be the least compacted. The presence of long, complex, and sometimes overlapping branching networks imply multiple relative episodes of channel formation. Rounded meso-yardangs, which are associated with salt playa surfaces on Earth, provide additional evidence for the presence of liquid water

  11. First record of the invasive medusa Blackfordia virginica (Hydrozoa: Leptomedusae in the Río de la Plata estuary, Argentina-Uruguay Primer registro de la medusa invasora Blackfordia virginica (Hydrozoa: Leptomedusae en el estuario del Río de la Plata, Argentina-Uruguay

    Directory of Open Access Journals (Sweden)

    GABRIEL GENZANO

    2006-06-01

    Full Text Available Blackfordia virginica is a well-known invasive medusa inhabiting estuarine areas. It was recently detected in northern Argentina, constituting the first record of invasive hydromedusa for the Argentine Sea. In this work more than 1,500 plankton samples in the southwestern Atlantic Ocean (34-55º S from 1983 to 2000 were analyzed. More than 5,000 specimens per sample of B. virginica were found in Río de la Plata estuary for the first time in February 2000. This river is one of the large waterways of South America with an intense nautical traffic and several exotic species has been recorded here, mainly due to trans-oceanic shipping traffic. It is important to point out that we found medusae of both sexes (therefore this species could be introduced in either the medusa or the polyp stages or both, different size classes (including very small juveniles and maturation stages, and in such high numbers that would suggest local reproduction. For this reason the recent finding of this hydromedusa could represent the starting point of an successful introductionBlackfordia virginica es una medusa invasora reconocida por habitar áreas estuariales. Recientemente fue descubierta en el norte de Argentina, constituyendo el primer registro de una hidromedusa invasora para el mar argentino. En este trabajo se analizaron más de 1.500 muestras de plancton en el Océano Atlántico sudoccidental (34-55º S desde 1983 hasta el año 2000. Más de 5.000 especímenes por muestra fueron encontrados por primera vez en el estuario del Río de la Plata durante febrero del año 2000. Este río es una de las mayores vías de agua de América del Sur, posee un intenso tráfico náutico y varias especies exóticas se han registrado allí, principalmente debido al tráfico marítimo transoceánico. Es importante señalar que se encontraron medusas de ambos sexos (por lo tanto esta especie podría haber sido introducida en su estadio medusa, pólipo o ambos, con diferentes

  12. Medusa-Isosampler: A modular, network-based observatory system for combined physical, chemical and microbiological monitoring, sampling and incubation of hydrothermal and cold seep fluids

    Science.gov (United States)

    Schultz, A.; Flynn, M.; Taylor, P.

    2004-12-01

    The study of life in extreme environments provides an important context from which we can undertake the search for extraterrestrial life, and through which we can better understand biogeochemical feedback in terrestrial hydrothermal and cold seep systems. The Medusa-Isosampler project is aimed at fundamental research into understanding the potential for, and limits to, chemolithoautotrophic life, i.e. primary production without photosynthesis. One environment that might foster such life is associated with the high thermal and chemical gradient environment of hydrothermal vent structures. Another is associated with the lower thermal and chemical gradient environment of continental margin cold seeps. Under NERC, NASA and industrial support, we have designed a flexible instrumentation system, operating as networked, autonomous modules on a local area network, that will make possible simultaneous physical and chemical sampling and monitoring of hydrothermal and cold seep fluids, and the in situ and laboratory incubation of chemosynthetic microbes under high pressure, isobaric conditions. The system has been designed with long-term observatory operations in mind, and may be reconfigured dynamically as the requirements of the observatory installation change. The modular design will also accommodate new in situ chemical and biosensor technologies, provided by third parties. The system may be configured for seafloor use, and can be adapted to use in IODP boreholes. Our overall project goals are provide an instrumentation system capable of probing both high and low-gradient water-rock systems for chemolithoautotrophic biospheres, to identify the physical and chemical conditions that define these microhabitats and explore the details of the biogeochemical feedback loops that mediate these microhabitats, and to attempt to culture and identify chemolithoautotrophic microbial communities that might exist there. The Medusa-Isosampler system has been produced and is now

  13. Influences of temperature and salinity on asexual reproduction and development of scyphozoan jellyfish from the British Isles

    OpenAIRE

    Widmer, Chad L.

    2015-01-01

    Jellyfish (Phylum Cnidaria, Class Scyphozoa) play important roles in pelagic ecosystems as predators and prey. Seasonally they form blooms facilitating reproductive success, but that are at times problematic for human enterprise. Medusa abundance has been correlated with environmental variables in several instances. However, the direct mechanisms for changes in medusa abundance are unclear. As global sea surface temperatures continue to change there is increasing concern that warming may enha...

  14. Monitoring the airborne dust and water vapor in the low atmosphere of Mars: the MEDUSA experiment for the ESA ExoMars mission

    Science.gov (United States)

    Esposito, Francesca; Colangeli, Luigi; Palumbo, Pasquale; Della Corte, Vincenzo; Molfese, Cesare; Merrison, Jonathan; Nornberg, Per; Lopez-Moreno, J. J.; Rodriguez Gomez, Julio

    rates and geographic variability are matter of controversy. The instrument MEDUSA (Martian Environmental DUst Systematic Analyser) has been designed to measure directly and quantitatively in situ the cumulative dust mass flux and dust deposition rate, the physical and electrification properties, the size distribution of intercepted particles and the water vapour abundance versus time, a goal that has never been reached so far. MEDUSA has been selected by ESA as one of the environmental instruments to be included in the payload Humboldt of ExoMars lander.

  15. Effects of dietary polysaccharides from the submerged fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. on fat deposition in broilers.

    Science.gov (United States)

    Shang, Hong Mei; Song, Hui; Shen, Si Jie; Yao, Xu; Wu, Bo; Wang, Li Na; Jiang, Yun Yao; Ding, Guo Dong

    2015-01-01

    The present study was conducted to investigate the lipid-lowering effect of polysaccharides from the submerged fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. (HFCP) in broilers. A total of 480 female Arbor Acres broilers were randomly divided into four dietary treatments, each consisting of six pens as replicates, and fed diets containing 0 (control), 1, 3 or 5 g kg(-1) HFCP. The results revealed that the average daily gain of broilers increased (linear (L), P < 0.01; quadratic (Q), P < 0.01) when the HFCP levels increased. The serum cholesterol, triglyceride and low-density lipoprotein cholesterol levels decreased (Q, P < 0.05) while the high-density lipoprotein cholesterol level increased (Q, P < 0.05) when the HFCP levels increased. The caecum Escherichia coli count and pH decreased (Q, P < 0.01) while the lactobacilli count and bifidobacteria count increased (L, P < 0.05; Q, P < 0.05) when the HFCP levels increased. The propionic acid and butyric acid concentrations increased (L, P < 0.001; Q, P < 0.001) while the abdominal fat rate and liver fat content decreased (L, P < 0.01; Q, P < 0.05) when the HFCP levels increased. Dietary supplementation with HFCP may lead to the development of low abdominal fat of broilers as demanded by health-conscious consumers. © 2014 Society of Chemical Industry.

  16. Summer composition and distribution of the jellyfish (Cnidaria: Medusozoa in the shelf area off the central Mexican Pacific Composición y distribución de las medusas (Cnidaria: Medusozoa en la plataforma continental central del Pacifico mexicano

    Directory of Open Access Journals (Sweden)

    Lourdes Segura-Puertas

    2010-04-01

    Full Text Available The composition, distribution, and abundance of the jellyfish community of a shelf area of the Mexican tropical Pacific were surveyed during August 1988. Zooplankton samples were collected along transects on the outer and inner sectors of the continental shelf to determine the structure of the jellyfish community and its variation in this area during the rainy season. A total of 23 species were recorded, with Aglaura hemistoma, Solmundella bitentaculata, Liriope tetraphylla, Pelagia noctiluca, and Rhopalonema velatum being the most abundant. The total abundance of medusae and of the most abundant species was statistically independent of depth and distance to the coast. Hence, the total jellyfish abundance of the most abundant species, and Shannon's Diversity index had a uniform distribution in both the inner and the outer shelf; furthermore, neritic-oceanic forms and oceanic species occurred indistinctly over the entire continental shelf. On the outer shelf A. hemistoma and S. bitentaculata were most abundant; the former species, together with L. tetraphylla, weakly characterized the inner shelf jellyfish community. The narrowness of the shelf, the wide distribution of the most abundant forms, and the possible effect of local advective processes from the oceanic zone masked a definite gradient across the shelf. Three species have not been recorded previously in the Mexican Pacific: Amphinema dinema (Péron and Lesueur, 1810, Sarsia coccometra Bigelow, 1909, and Clytia mccradyi (Brooks, 1888. The finding of A. dinema is the first in the Eastern Pacific.Se estudió la composición, distribución y abundancia de la comunidad de medusas de la plataforma continental en el Pacífico mexicano durante agosto 1988. Las muestras de zooplancton provienen de transectos en las zonas externa e interna de la plataforma para determinar la estructura de la comunidad de medusas y su variación durante la época de lluvias. Se identificaron 23 especies; las m

  17. Effects of dietary fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. on growth performance, digestibility, and intestinal microbiology and morphology in broiler chickens.

    Science.gov (United States)

    Shang, Hong Mei; Song, Hui; Xing, Ya Li; Niu, Shu Li; Ding, Guo Dong; Jiang, Yun Yao; Liang, Feng

    2016-01-15

    The present study was undertaken to investigate the effects of fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. (HFC) on growth performance, digestibility, intestinal microbiology, and intestinal morphology in broiler chickens. A total of 600 male Arbor Acres broilers were randomly divided into five dietary treatments (20 broilers per pen with six pens per treatment): CON (basal diet), ANT (basal diet supplemented with 5 mg kg(-1) flavomycin) and HFC (basal diet supplemented with 6, 12, and 18 g kg(-1) HFC). The experimental lasted for 42 days. The results revealed that the average daily gain [linear (L), P < 0.01; quadratic (Q), P < 0.01] of broilers increased when the HFC levels increased during the starter (days 1-21), finisher (days 22-42), and the overall experiment period (days 1 to 42). In the small intestinal digesta and the caecum digesta, the Escherichia coli count (L, P < 0.05; Q, P < 0.001) decreased while the Lactobacilli count (L, P < 0.01; Q, P < 0.001) and Bifidobacteria count (L, P < 0.001; Q, P < 0.001) increased when the HFC levels increased. The crude protein digestibility of broilers (L, P < 0.01; Q, P < 0.001) increased when the HFC levels increased. In the duodenum, jejunum, and ileum of broilers, the villus height and villus height to crypt depth ratio (L, P < 0.001; Q, P < 0.001) increased when the HFC levels increased. Dietary supplementation with HFC increased gut Lactobacilli and Bifidobacteria counts and inhibited E. coli growth, improved nutrient utilisation and intestine villus structure, and thus improved the growth of broilers. © 2015 Society of Chemical Industry.

  18. Indoles induce metamorphosis in a broad diversity of jellyfish, but not in a crown jelly (Coronatae).

    Science.gov (United States)

    Helm, Rebecca R; Dunn, Casey W

    2017-01-01

    Many animals go through one or more metamorphoses during their lives, however, the molecular underpinnings of metamorphosis across diverse species are not well understood. Medusozoa (Cnidaria) is a clade of animals with complex life cycles, these life cycles can include a polyp stage that metamorphoses into a medusa (jellyfish). Medusae are produced through a variety of different developmental mechanisms-in some species polyps bud medusae (Hydrozoa), in others medusae are formed through polyp fission (Scyphozoa), while in others medusae are formed through direct transformation of the polyp (Cubozoa). To better understand the molecular mechanisms that may coordinate these different forms of metamorphosis, we tested two compounds first identified to induce metamorphosis in the moon jellyfish Aurelia aurita (indomethacin and 5-methoxy-2-methylindole) on a broad diversity of medusozoan polyps. We discovered that indole-containing compounds trigger metamorphosis across a broad diversity of species. All tested discomedusan polyps metamorphosed in the presence of both compounds, including species representatives of several major lineages within the clade (Pelagiidae, Cyaneidae, both clades of Rhizostomeae). In a cubozoan, low levels of 5-methoxy-2-methylindole reliably induced complete and healthy metamorphosis. In contrast, neither compound induced medusa metamorphosis in a coronate scyphozoan, or medusa production in either hydrozoan tested. Our results support the hypothesis that metamorphosis is mediated by a conserved induction pathway within discomedusan scyphozoans, and possibly cubozoans. However, failure of these compounds to induce metamorphosis in a coronate suggests this induction mechanism may have been lost in this clade, or is convergent between Scyphozoa and Cubozoa.

  19. Fecundidad de la medusa Stomolophus meleagris (Rhizostomeae: Stomolophidae en el Golfo de California Stomolophus meleagris fecundity (Rhizostomeae: Stomolophidae in the Gulf of California

    Directory of Open Access Journals (Sweden)

    Liliana Carvalho Saucedo

    2012-12-01

    Full Text Available La medusa Stomolophus meleagris es considerada un recurso pesquero de alto valor comercial. Debido a la relevancia de conocer aspectos de importancia biológica actualmente desconocidos, el presente trabajo analiza la fecundidad con base en la estimación del número de ovocitos vitelogénicos en la gónada; su relación con la longitud, diámetro y peso húmedo; y la relación del índice gonadosomático (IGS con su diámetro y longitud. De enero a mayo 2006 se recolectaron 30 ejemplares mensuales que fueron medidos y pesados, de los cuales se analizaron 60 hembras maduras para calcular el volumen de sus gónadas. Se extrajeron las gónadas, se tiñeron con hematoxilina-eosina y se seleccionaron las hembras con madurez gonadal. Mediante la digitalización de imágenes se estimó el número de ovocitos vitelogénicos y previtelogénicos. Se emplearon datos de captura en Las Guásimas para el análisis de reclutamiento poblacional, estimado con FISAT II. La fecundidad se incrementó con la longitud, el diámetro y el peso húmedo total. La menor fecundidad se observó en febrero y la mayor en mayo (11 873 071 y 37 528 197 millones de ovocitos vitelogénico por gónada, respectivamente. El IGS se incrementó con la longitud y diámetro de los ejemplares, con su máximo en mayo de 3.7%. Se observó una producción continua de ovocitos previtelogénicos en todo el periodo de recolecta. El máximo reclutamiento se observó en julio y noviembre (37.50% y 28.01% respectivamente. La alta fecundidad encontrada en S. meleagris sugiere un alto potencial reproductivo para la población y sustenta la posibilidad de la consolidación de una importante pesquería de esta medusa.The cannonball jellyfish Stomolophus meleagris is regarded as a fishery resource with high commercial value, but with scarce biological information. With the aim to generate preliminary information on reproductive aspects, the present study analyzes its fecundity, based on the estimated

  20. Hericium caput-medusae (Bull.:Fr.) Pers. polysaccharide enhance innate immune response, immune-related genes expression and disease resistance against Aeromonas hydrophila in grass carp (Ctenopharyngodon idella).

    Science.gov (United States)

    Gou, Changlong; Wang, Jiazhen; Wang, Yuqiong; Dong, Wenlong; Shan, Xiaofeng; Lou, Yujie; Gao, Yunhang

    2018-01-01

    The objective was to add 0, 400, 800 or 1200 mg/kg of Hericium caput-medusae polysaccharide (HCMP) to the basal diet of grass carp (Ctenopharyngodon idella) and determine effects on humoral innate immunity, expression of immune-related genes and disease resistance. Adding HCMP enhanced (P < 0.05) bactericidal activity at 1, 2 and 3 weeks and also lysozyme activity, complement C3, and SOD activity at 2 and 3 weeks. Supplementing 800 or 1200 mg/kg of HCMP for 2 or 3 weeks increased (P < 0.05) serum concentrations of total protein, albumin and globulin. Two immune-related genes (IL-1β and TNF-α) were up-regulated (P < 0.05) in HCMP supplemented groups given 800 or 1200 mg/kg HCMP after 2 and 3 weeks of feeding. Expression of anti-inflammatory cytokine IL-10 was down-regulated (P < 0.05) after receiving 800 or 1200 mg/kg HCMP for 2 or 3 weeks. Fish fed 800 mg/kg HCMP had maximal disease resistance against Aeromonas hydrophila (65.4%). In conclusion, HCMP enhanced immune response and expression of immune-related genes and increased disease resistance against Aeromonas hydrophila in grass carp, with greatest effects in fish given 800 mg/kg HCMP for 3 weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Mechanistic site-based emulation of a global ocean biogeochemical model (MEDUSA 1.0 for parametric analysis and calibration: an application of the Marine Model Optimization Testbed (MarMOT 1.1

    Directory of Open Access Journals (Sweden)

    J. C. P. Hemmings

    2015-03-01

    Full Text Available Biogeochemical ocean circulation models used to investigate the role of plankton ecosystems in global change rely on adjustable parameters to capture the dominant biogeochemical dynamics of a complex biological system. In principle, optimal parameter values can be estimated by fitting models to observational data, including satellite ocean colour products such as chlorophyll that achieve good spatial and temporal coverage of the surface ocean. However, comprehensive parametric analyses require large ensemble experiments that are computationally infeasible with global 3-D simulations. Site-based simulations provide an efficient alternative but can only be used to make reliable inferences about global model performance if robust quantitative descriptions of their relationships with the corresponding 3-D simulations can be established. The feasibility of establishing such a relationship is investigated for an intermediate complexity biogeochemistry model (MEDUSA coupled with a widely used global ocean model (NEMO. A site-based mechanistic emulator is constructed for surface chlorophyll output from this target model as a function of model parameters. The emulator comprises an array of 1-D simulators and a statistical quantification of the uncertainty in their predictions. The unknown parameter-dependent biogeochemical environment, in terms of initial tracer concentrations and lateral flux information required by the simulators, is a significant source of uncertainty. It is approximated by a mean environment derived from a small ensemble of 3-D simulations representing variability of the target model behaviour over the parameter space of interest. The performance of two alternative uncertainty quantification schemes is examined: a direct method based on comparisons between simulator output and a sample of known target model "truths" and an indirect method that is only partially reliant on knowledge of the target model output. In general, chlorophyll

  2. The Medusa Algorithm for Polynomial Matings

    DEFF Research Database (Denmark)

    Boyd, Suzanne Hruska; Henriksen, Christian

    2012-01-01

    of its Julia set. Whether these approximations converge is answered using Thurston's topological characterization of rational maps. This algorithm was designed by John Hamal Hubbard, and implemented in 1998 by Christian Henriksen and REU students David Farris and Kuon Ju Liu. In this paper we describe...

  3. Entre la Venadita y la Medusa

    Directory of Open Access Journals (Sweden)

    Valcárcel, Amelia

    2008-06-01

    Full Text Available Feminism has made in the last decades relevant advances towards equity between men and women in western societies. However, both mysogyny and gynophobia are still at work, giving as a result a «deflation of expectations» among women who enter the worlds of politics, information, corporations, economic power, knowledge, religion or art, and find a glass ceiling in full operation. The paper focuses on women artists, examines the anger expressed in feminist art as an answer to exclusion, and argues for feminist strategies of analysis and correction of inequalities.

    El feminismo ha conseguido en los últimos años importantes avances hacia la igualdad entre hombres y mujeres en las sociedades occidentales. Y, sin embargo, tanto la misoginia como la ginofobia siguen vigentes, provocando una «deflación de expectativas » entre las mujeres que se incorporan a los mundos de la política, la información, las organizaciones empresariales, el poder económico, el saber, la religión o la creatividad, y se topan con el techo de cristal a pleno funcionamiento. El artículo se centra en las mujeres creadoras para examinar la cólera expresada en el arte feminista como respuesta a la exclusión y defender estrategias feministas de análisis y corrección de desigualdades.

  4. Beyond Medusa: recovering history on stage

    NARCIS (Netherlands)

    Röttger, K.

    2010-01-01

    The theatre work of the Austrian Elfriede Jelinek is known for its critique of mythology. In her recent "work in progress", which closely follows media reports about the Iraq war and the tortures in Abu Ghraib, Jelinek concentrates on the mythologizing effects of a "wartainment" that a supposedly

  5. Medusa: um ambiente musical distribuído

    OpenAIRE

    Flávio Luiz Schiavoni

    2013-01-01

    A popularização das redes de computadores, o aumento da capacidade computacional e sua utilização para produção musical despertam o interesse na utilização de computadores para comunicação síncrona de conteúdo musical. Esta comunicação pode permitir um novo nível de interatividade entre máquinas e pessoas nos processos de produção musical, incluindo a distribuição de atividades, pessoas e recursos em um ambiente computacional em rede. Neste contexto, este trabalho apresenta uma solução para c...

  6. Pelagia noctiluca (Scyphozoa Crude Venom Injection Elicits Oxidative Stress and Inflammatory Response in Rats

    Directory of Open Access Journals (Sweden)

    Giuseppe Bruschetta

    2014-04-01

    Full Text Available Cnidarian toxins represent a rich source of biologically active compounds. Since they may act via oxidative stress events, the aim of the present study was to verify whether crude venom, extracted from the jellyfish Pelagia noctiluca, elicits inflammation and oxidative stress processes, known to be mediated by Reactive Oxygen Species (ROS production, in rats. In a first set of experiments, the animals were injected with crude venom (at three different doses 6, 30 and 60 µg/kg, suspended in saline solution, i.v. to test the mortality and possible blood pressure changes. In a second set of experiments, to confirm that Pelagia noctiluca crude venom enhances ROS formation and may contribute to the pathophysiology of inflammation, crude venom-injected animals (30 µg/kg were also treated with tempol, a powerful antioxidant (100 mg/kg i.p., 30 and 60 min after crude venom. Administration of tempol after crude venom challenge, caused a significant reduction of each parameter related to inflammation. The potential effect of Pelagia noctiluca crude venom in the systemic inflammation process has been here demonstrated, adding novel information about its biological activity.

  7. Tentacle Transcriptome and Venom Proteome of the Pacific Sea Nettle, Chrysaora fuscescens (Cnidaria: Scyphozoa)

    Science.gov (United States)

    Ponce, Dalia; Brinkman, Diane L.; Potriquet, Jeremy; Mulvenna, Jason

    2016-01-01

    Jellyfish venoms are rich sources of toxins designed to capture prey or deter predators, but they can also elicit harmful effects in humans. In this study, an integrated transcriptomic and proteomic approach was used to identify putative toxins and their potential role in the venom of the scyphozoan jellyfish Chrysaora fuscescens. A de novo tentacle transcriptome, containing more than 23,000 contigs, was constructed and used in proteomic analysis of C. fuscescens venom to identify potential toxins. From a total of 163 proteins identified in the venom proteome, 27 were classified as putative toxins and grouped into six protein families: proteinases, venom allergens, C-type lectins, pore-forming toxins, glycoside hydrolases and enzyme inhibitors. Other putative toxins identified in the transcriptome, but not the proteome, included additional proteinases as well as lipases and deoxyribonucleases. Sequence analysis also revealed the presence of ShKT domains in two putative venom proteins from the proteome and an additional 15 from the transcriptome, suggesting potential ion channel blockade or modulatory activities. Comparison of these potential toxins to those from other cnidarians provided insight into their possible roles in C. fuscescens venom and an overview of the diversity of potential toxin families in cnidarian venoms. PMID:27058558

  8. Tentacle Transcriptome and Venom Proteome of the Pacific Sea Nettle, Chrysaora fuscescens (Cnidaria: Scyphozoa

    Directory of Open Access Journals (Sweden)

    Dalia Ponce

    2016-04-01

    Full Text Available Jellyfish venoms are rich sources of toxins designed to capture prey or deter predators, but they can also elicit harmful effects in humans. In this study, an integrated transcriptomic and proteomic approach was used to identify putative toxins and their potential role in the venom of the scyphozoan jellyfish Chrysaora fuscescens. A de novo tentacle transcriptome, containing more than 23,000 contigs, was constructed and used in proteomic analysis of C. fuscescens venom to identify potential toxins. From a total of 163 proteins identified in the venom proteome, 27 were classified as putative toxins and grouped into six protein families: proteinases, venom allergens, C-type lectins, pore-forming toxins, glycoside hydrolases and enzyme inhibitors. Other putative toxins identified in the transcriptome, but not the proteome, included additional proteinases as well as lipases and deoxyribonucleases. Sequence analysis also revealed the presence of ShKT domains in two putative venom proteins from the proteome and an additional 15 from the transcriptome, suggesting potential ion channel blockade or modulatory activities. Comparison of these potential toxins to those from other cnidarians provided insight into their possible roles in C. fuscescens venom and an overview of the diversity of potential toxin families in cnidarian venoms.

  9. The Bright Side of Gelatinous Blooms: Nutraceutical Value and Antioxidant Properties of Three Mediterranean Jellyfish (Scyphozoa

    Directory of Open Access Journals (Sweden)

    Antonella Leone

    2015-07-01

    Full Text Available Jellyfish are recorded with increasing frequency and magnitude in many coastal areas and several species display biological features comparable to the most popular Asiatic edible jellyfish. The biochemical and antioxidant properties of wild gelatinous biomasses, in terms of nutritional and nutraceutical values, are still largely unexplored. In this paper, three of the most abundant and commonly recorded jellyfish species (Aurelia sp.1, Cotylorhiza tuberculata and Rhizostoma pulmo in the Mediterranean Sea were subject to investigation. A sequential enzymatic hydrolysis of jellyfish proteins was set up by pepsin and collagenase treatments of jellyfish samples after aqueous or hydroalcoholic protein extraction. The content and composition of proteins, amino acids, phenolics, and fatty acids of the three species were recorded and compared. Protein content (mainly represented by collagen up to 40% of jellyfish dry weight were found in two of the three jellyfish species (C. tuberculata and R. pulmo, whereas the presence of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs was significantly higher in the zooxanthellate jellyfish C. tuberculata only. Remarkable antioxidant ability was also recorded from both proteinaceous and non proteinaceous extracts and the hydrolyzed protein fractions in all the three species. The abundance of collagen, peptides and other bioactive molecules make these Mediterranean gelatinous biomasses a largely untapped source of natural compounds of nutraceutical, cosmeceutical and pharmacological interest.

  10. Sexual reproduction of Nausithoe aurea (Scyphozoa, Coronatae. Gametogenesis, egg release, embryonic development, and gastrulation

    Directory of Open Access Journals (Sweden)

    André C. Morandini

    2001-06-01

    Full Text Available The structure of the ovaries and testes of Nausithoe aurea, reared in the laboratory, is described to update the knowledge of coronate scyphomedusae gametogenesis and early development. The testis is similar to those of other scyphozoans. The organization of the ovary agrees with the description for other coronates, with free oocytes in the mesoglea. The oocytes develop in a limited region of the gastrodermis, and a maturation gradient is observed from this point on. Egg release, embryonic development, and gastrulation mode of Nausithoe aurea are also described. Egg production was continuous for 55 days, and the output of released eggs oscillated without observed cue. Cleavage was holoblastic and adequal, but after the 8-cell stage, the cleavage became pseudospiral. Gastrulation occurred through multipolar ingression and began 24 hours after fertilization.

  11. Medusa spectroscopy of A400, A576, A1767, and A2124

    International Nuclear Information System (INIS)

    Hintzen, P.; Hill, J.M.; Lindley, D.; Scott, J.S.; Angel, J.R.P.

    1982-01-01

    Galaxy velocity data taken with the Steward Observatory multiple aperture fiber optic spectrograph are presented for four Abell clusters. The root-mean-square external errors in these velocities are about 100 km/s; accuracy which compares favorably with that obtained from single-object observations. We expect that the recent adoption of a CCD detector should decrease external errors to about 50 km/s. All four of the clusters observed are known x-ray sources and our data agree well with empirically derived velocity dispersion--x-ray luminosity relations for clusters of galaxies. Abell 400 is interesting in this regard, since both its x-ray luminosity and its velocity dispersion are quite small. Such objects are particularly important in determining the slope of the velocity dispersion--x-ray luminosity relation. The large microwave decrement observed in A576 was initially interpreted as due to Compton scattering of the microwave background by the x-ray-emitting intracluster gas. White and Silk have presented Einstein x-ray data which indicate that A576 contains too little gas to produce the observed microwave decrement by Compton scattering. Our velocity dispersion for 47 members of this cluster strengthens their conclusion

  12. Medusa spectroscopy of A400, A576, A1767, and A2124

    Science.gov (United States)

    Hintzen, P.; Hill, J. M.; Lindley, D.; Scott, J. S.; Angel, J. R. P.

    1982-01-01

    Galaxy velocity data taken with the Steward Observatory multiple aperture fiber optic spectrograph are presented for four Abell clusters. The root-mean-square external errors in these velocities are about 100 km/s; accuracy which compares favorably with that obtained from single-object observations. It is expected that the recent adoption of a CCD detector should decrease external errors to about 50 km/s. All four of the clusters observed are known X-ray sources and the present data agree well with empirically derived velocity dispersion-X-ray luminosity relations for clusters of galaxies. Abell 400 is interesting in this regard, since both its X-ray luminosity and its velocity dispersion are quite small. Such objects are particularly important in determining the slope of the velocity dispersion-X-ray luminosity relation. The large microwave decrement observed in A576 was initially interpreted as due to Compton scattering of the microwave background by the X-ray-emitting intracluster gas. White and Silk have presented Einstein X-ray data which indicate that A576 contains too little gas to produce the observed microwave decrement by Compton scattering. The velocity dispersion obtained here for 47 members of this cluster strengthens their conclusion.

  13. Para além de Medusa: retomar a história no palco

    NARCIS (Netherlands)

    Röttger, K.

    2011-01-01

    O trabalho em teatro da austríaca Elfridine Jelinek é conhecido por sua crítica da mitologia. No seu recente 'work in progress', que segue de perto os relatos da mídia sobre a Guerra do Iraque e as torturas em Abu Ghraib, Jelinek concentra-se no efeito mitologizante do 'wartainment' que uma

  14. MEDUSA - An overset grid flow solver for network-based parallel computer systems

    Science.gov (United States)

    Smith, Merritt H.; Pallis, Jani M.

    1993-01-01

    Continuing improvement in processing speed has made it feasible to solve the Reynolds-Averaged Navier-Stokes equations for simple three-dimensional flows on advanced workstations. Combining multiple workstations into a network-based heterogeneous parallel computer allows the application of programming principles learned on MIMD (Multiple Instruction Multiple Data) distributed memory parallel computers to the solution of larger problems. An overset-grid flow solution code has been developed which uses a cluster of workstations as a network-based parallel computer. Inter-process communication is provided by the Parallel Virtual Machine (PVM) software. Solution speed equivalent to one-third of a Cray-YMP processor has been achieved from a cluster of nine commonly used engineering workstation processors. Load imbalance and communication overhead are the principal impediments to parallel efficiency in this application.

  15. Las miradas poéticas de Narciso y Medusa: la transformacion de lo real

    Directory of Open Access Journals (Sweden)

    Sergio Blanco

    2015-04-01

    Full Text Available Al ser director tanto académico como artístico de este proyecto europeo Crossing Stages, esta doble condición me lleva a tomar la palabra desde estos dos lugares, es decir, desde lo académico y desde lo artístico. Desde dos lugares entonces casi antagónicos. La toma de la palabra académica responde en cierta forma a ciertas máximas de claridad y precisión, suele tender a ser un discurso mesurado, ordenado y equilibrado, que en cierta forma busca un conocimiento erudito por medio de procedimientos científicos lo más objetivos y sólidos posibles. Mientras que la toma de la palabra artística es todo lo contrario, es una palabra oscura, confusa, hiperbólica, amanerada, completamente desmesurada y caótica, y basada en experiencias y caprichos inminentemente subjetivos. Se me plantea entonces desde qué lugar hablar:  

  16. MedusaScore: An accurate force field-based scoring function for virtual drug screening

    Czech Academy of Sciences Publication Activity Database

    Yin, S.; Biedermannová, Lada; Vondrášek, Jiří; Dokholyan, N. V.

    2008-01-01

    Roč. 48, č. 8 (2008), s. 1656-1662 ISSN 1549-9596 Grant - others:NIH(US) RO1-GM080742 Institutional research plan: CEZ:AV0Z40550506 Keywords : free-energy calculation * protein-ligand complex * binding-affinity * flexible docking * molecular recognition Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.643, year: 2008

  17. MEDUSA: Mining Events to Detect Undesirable uSer Actions in SCADA

    NARCIS (Netherlands)

    Hadziosmanovic, D.; Bolzoni, D.; Hartel, Pieter H.; Jha, Somesh; Sommer, Robin; Kreibich, Christian

    2010-01-01

    Standard approaches for detecting malicious behaviors, e.g. monitoring network traffic, cannot address process-related threats in SCADA(Supervisory Control And Data Acquisition) systems. These threats take place when an attacker gains user access rights and performs actions which look legitimate,

  18. Biogeographical plant-soil relations of invasive medusahead (Elymus caput-medusae)

    Science.gov (United States)

    Understanding the mechanisms that underlie the success of invasive plant species is integral to predicting and ameliorating their negative impacts. Many hypotheses have consequently been proposed to explain invasive behavior. This lack of consensus within invasion ecology can partially be attributed...

  19. FMRFamide immunoreactivity in the nervous system of the medusa Polyorchis penicillatus

    DEFF Research Database (Denmark)

    Grimmelikhuijzen, C J; Spencer, A N

    1984-01-01

    with several antisera to oxytocin/vasopressin and bombesin/gastrin-releasing peptide. The morphology and location of most FMRFamide-immunoreactive neurons in Polyorchis coincides with two identified neuronal systems, which have been recently discovered from neurophysiological studies....... immunoreactivity was found in neurons of the ectodermal nerve nets of the manubrium and tentacles, in neurons of the sensory epithelium, and in neurons at the periphery of the sphincter muscle. Strong immunoreactivity was also present in processes and perikarya of the whole outer nerve ring, in the ocellar nerves...

  20. Crude venom from nematocysts of Pelagia noctiluca (Cnidaria: Scyphozoa) elicits a sodium conductance in the plasma membrane of mammalian cells

    Science.gov (United States)

    Morabito, Rossana; Costa, Roberta; Rizzo, Valentina; Remigante, Alessia; Nofziger, Charity; La Spada, Giuseppa; Marino, Angela; Paulmichl, Markus; Dossena, Silvia

    2017-01-01

    Cnidarians may negatively impact human activities and public health but concomitantly their venom represents a rich source of bioactive substances. Pelagia noctiluca is the most venomous and abundant jellyfish of the Mediterranean Sea and possesses a venom with hemolytic and cytolytic activity for which the mechanism is largely unknown. Here we show that exposure of mammalian cells to crude venom from the nematocysts of P. noctiluca profoundly alters the ion conductance of the plasma membrane, therefore affecting homeostatic functions such as the regulation and maintenance of cellular volume. Venom-treated cells exhibited a large, inwardly rectifying current mainly due to permeation of Na+ and Cl-, sensitive to amiloride and completely abrogated following harsh thermal treatment of crude venom extract. Curiously, the plasma membrane conductance of Ca2+ and K+ was not affected. Current-inducing activity was also observed following delivery of venom to the cytosolic side of the plasma membrane, consistent with a pore-forming mechanism. Venom-induced NaCl influx followed by water and consequent cell swelling most likely underlie the hemolytic and cytolytic activity of P. noctiluca venom. The present study underscores unique properties of P. noctiluca venom and provides essential information for a possible use of its active compounds and treatment of envenomation.

  1. Environmental control of asexual reproduction and somatic growth of Aurelia spp. (Cnidaria, Scyphozoa) polyps from the Adriatic Sea

    OpenAIRE

    Hubot, Nathan; Lucas, Cathy H.; Piraino, Stefano

    2017-01-01

    Polyps of two moon jellyfish species, Aurelia coerulea and A.relicta, from two Adriatic Sea coastal habitats were incubated under multiple combinations of temperature (14, 21 °C), salinity (24, 37 ppt) and food regime (9.3, 18.6, 27.9 μg C ind‾¹ week‾¹) to comparatively assess how these factors may influence major asexual reproduction processes in the two species. Both species exhibited a shared pattern of budding mode (Directly Budded Polyps: DBP; Stolonal Budded Polyps: SBP), with DBP favo...

  2. North Sea Scyphomedusae; summer distribution, estimated biomass and significance particularly for 0-group Gadoid fish

    Science.gov (United States)

    Hay, S. J.; Hislop, J. R. G.; Shanks, A. M.

    Data on the by-catch of Scyphomedusae from pelagic trawls was collected during the routine ICES International 0-group Gadoid Surveys of the North Sea, in June and July of the years 1971-1986 (except 1984). These data are used to describe the distributions, abundances and biomasses of three common North Sea Scyphomedusae: Aurelia aurita (L.), Cyanea capillata (L.) and C. lamarckii (Péron & Lesuer). Information is also presented on inter-annual variability, size (umbrella diameter) frequencies and, for the Cyanea species, umbrella diameter: wet weight relationships. The general role and ecological significance of Scyphomedusae is discussed and, given the well known 'shelter' relationships between Scyphomedusae and certain 0-group fish, whiting ( Merlangius merlangus) and haddock ( Melanogrammus aeglefinus), in particular. The data were examined for evidence of such relationships. Aurelia aurita, although fairly widespread in the northern North Sea was virtually absent from the central North Sea but very abundant in coastal waters. This species was particularly abundant off the Scottish east coast and especially in the Moray Firth. Cyanea lamerckii was most abundant in the southern and eastern North Sea. More widespread than Aurelia, this species was also most abundant in coastal regions, particularly off the Danish west coast. Cyanea capillata, with a more northern distribution was also more widely distributed and abundant offshore. This species was most abundant in the area between the Orkney/Shetland Isles and the Norwegian Deep and in shelf waters of the north west approaches to the North Sea. As with C. lamarckii it was also, in some years, abundant off the Scottish east coast and west of Denmark. The abundance and the size frequency of the jellyfish show considerable inter-annual variability, and variability between regions of the North Sea. It is considered that hydrographic variability and differences in food supply to both medusae and to their sessile

  3. Medusas (Cnidaria: Hydrozoa de una zona de afloramiento costero, Bahía Culebra, Pacífico, Costa Rica

    Directory of Open Access Journals (Sweden)

    Karina Rodríguez-Sáenz

    2012-12-01

    Full Text Available Las hidromedusas tienen un papel importante en redes tróficas marinas debido a sus hábitos alimenticios depredadores. Este es el primer estudio de este grupo del zooplancton gelatinoso en un area de afloramiento costero en América Central. Durante seis meses de 1999, se estudió la abundancia de hidromedusas en cuatro estaciones en Bahía Culebra, Golfo de Papagayo, costa Pacífica de Costa Rica (10º 37’N-85º40’W. Se identificó un total de 53 especies de las que 26 son registros nuevos para Costa Rica, 21 son registros nuevos para América Central y 8 son nuevos registros para el Pacífico Oriental Tropical. Las especies más abundantes durante el estudio (con más de 30% de la abundancia total fueron Liriope tetraphylla, Solmundella bitentaculata y Aglaura hemistoma. Seis especies se presentaron en todos los muestreos, 10 especies se presentaron únicamente durante la época seca y 17 se presentaron únicamente durante la época lluviosa. Se mostraron diferencias significativas entre las épocas lluviosa y seca. La máxima abundancia promedio de hidromedusas (2.1±4.3 ind./m³ fue encontrada durante las fechas que se espera el afloramiento costero, indicado por alta concentración de oxígeno y baja temperatura. La rica composición de especies encontrada en Bahía Culebra puede ser el resultado de varios factores, incluyendo la condición prístina de la bahía, el transporte de especies por la Contra Corriente Nor-Ecuatorial (NECC y los aportes de origen terrestre. Se incluyen ilustraciones de las 15 especies más importantes para facilitar su identificación y promover estudios futuros en la región.

  4. Medusae from the sea around Laccadive group of islands (7 degrees-18 degrees N/69 degrees-76 degrees E)

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    stream_size 7 stream_content_type text/plain stream_name 2_Workshop_Scient_Result_FORV_Sagar_Sampada_Proc_1996_249.pdf.txt stream_source_info 2_Workshop_Scient_Result_FORV_Sagar_Sampada_Proc_1996_249.pdf.txt Content-Encoding ISO-8859...

  5. The biogenic reefs formed by the alien polychaete Hydroides dianthus (Serpulidae, Annelida) favor the polyp stage of Aurelia coerulea (Cnidaria, Scyphozoa) in a coastal artificial lake.

    Science.gov (United States)

    Dong, Zhijun; Sun, Tingting; Wang, Lei

    2018-04-01

    Blooms of the moon jellyfish Aurelia coerulea frequently occur in coastal waters. The increased availability of substrates for the settlement and proliferation of polyps due to the expansion of artificial structures in coastal areas has been proposed as a possible contributing factor in jellyfish blooms. This paper investigates whether a marine artificial lake (Fenghuang Lake) provides additional substrates for A. coerulea polyps and contributes to jellyfish blooms. High densities of A. coerulea ephyrae were discovered in this lake, with a mean density of 41 individuals/m 3 and a maximum measured density of 128 individuals/m 3 . Meanwhile, A. coerulea ephyrae were also found in the two emptying channels outside the lake, with a mean density of 13 individuals/m 3 . Underwater surveys revealed that dense colonies of A. coerulea polyps occurred mainly on biogenic reefs formed by a polychaete, which was identified as an invasive serpulid species Hydroides dianthus, based on the phylogenetic analysis of mitochondrial COI gene sequences. Our study highlights the potential modification of habitats by the alien polychaete H. dianthus, which might provide complex benthic habits suitable for the settlement and proliferation of A. coerulea polyps and may contribute to jellyfish blooms in the marine artificial lake and nearby coastal waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Evolution of life cycle, colony morphology, and host specificity in the family Hydractiniidae (Hydrozoa, Cnidaria).

    Science.gov (United States)

    Miglietta, Maria Pia; Cunningham, Clifford W

    2012-12-01

    Biased transitions are common throughout the tree of life. The class hydrozoa is no exception, having lost the feeding medusa stage at least 70 times. The family hydractiniidae includes one lineage with pelagic medusae (Podocoryna) and several without (e.g., Hydractinia). The benthic colony stage also varies widely in host specificity and in colony form. The five-gene phylogeny presented here requires multiple transitions between character states for medusae, host specificity, and colony phenotype. Significant phylogenetic correlations exist between medusoid form, colony morphology, and host specificity. Species with nonfeeding medusae are usually specialized on a single host type, and reticulate colonies are correlated with nonmotile hosts. The history of feeding medusae is less certain. Podocoryna is nested within five lineages lacking medusae. This requires either repeated losses of medusae, or the remarkable re-evolution of a feeding medusa after at least 150 million years. Traditional ancestral reconstruction favors medusa regain, but a likelihood framework testing biased transitions cannot distinguish between multiple losses versus regain. A hypothesis of multiple losses of feeding medusae requires transient selection pressure favoring such a loss. Populations of species with feeding medusae are always locally rare and lack of feeding medusae does not result in restricted species distribution around the world. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  7. A study on the Gut contents of six Leathery Turtles Dermochelys Coriacea (Linnaeus) (Reptilia: Testudines: Dermochelyidae) from British waters and from the Netherlands

    NARCIS (Netherlands)

    Hartog, den J.C.; Nierop, van M.M.

    1984-01-01

    Microscopical investigations of the gut contents of six individuals of Dermochelys coriacea from southern England and the North Sea revealed the presence in all of these of numerous nematocysts, mainly scyphozoan. Only six species of Scyphozoa occur in British shallow waters and in the North Sea,

  8. (Cnidaria: Limnomedusae) from southern Africa

    African Journals Online (AJOL)

    1992-01-27

    Jan 27, 1992 ... the 1940s, when a number of exotic species were introduced, associated with man's ... its distribution from Europe, North America and China. 143. (Dejdar 1934 ... inter-basin transfers. The appearance of freshwater medusae.

  9. Occurrence of swarms of Sagitta enflata (Chaetognatha) and Pleurobrachia globosa (Ctenophora) in the coastal waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Swarms of Chaetognatha @iSagitta enflata@@ Grassi and Ctenophore @iPleurobrachia globosa@@. Moser were studied in coastal waters of Goa. These two forms together constituted 90 to 94% of total biomass. Medusae and Siphonophora were the other main...

  10. Toxic effects of domestic sewage on zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Nair, V.R.; Desai, B.N.

    that they are very sensitive to the sewage. Copepods, Lucifer and decapod larvae (20-30% concentration.) were moderately tolerant. Acetes, medusae, ctenophores and mysids were the most resistant groups (42-49% concentration)....

  11. Research for Development in the Middle East and North Africa

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

    Despite advances in the availability of hardware and accessories, and ..... The high degree of social stress is aggravated by serious qualitative retreats in the ...... 11 Medusa bags are floating plastic containers, pulled by boat to transport water.

  12. Success of seeding native compared with introduced perennial vegetation for revegetating medusahead-invaded sagebrush rangeland

    Science.gov (United States)

    Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity....

  13. Proterodiplostome Parasites (Digenea, Proterodiplostomidae of the Caiman, Caiman crocodilus yacare (Reptilia, Crocodylia in the Pantanal mato-Grossense, Brazil, with the description of two new species

    Directory of Open Access Journals (Sweden)

    João B. Catto

    1994-12-01

    Full Text Available Two new species are described from the caiman. Caiman crocodilus yacare. Proterodiplostomum breve n. sp. differs from all other species in the genus by the following chacacteristics: (1 the paraprostate gland is shorter and club-shaped; (2 the genital cone is, in average, eight times longer than that of P. medusae; (3 the genital atrium is larger and without pseudosuckers; (4 the oral sucker and pharynx are longer; and (5 there are larger numbers of papillae surrounding the tribocytic organ (40 against 20 in P. longum, 16 in p. tumidilum, 8 in P. ophidum, and 16-18 in P. medusae. Proterodiplostomum globulare n. sp. differs from all the other species in the fenus by the following characteristics: (1 from P. tumidilum, P. lomgum, P. medusae, and P. breve n. sp. for the absense of pseudosuckers or muscular bunches in the inferior wall of the genital atrium; (2 the shape of the paraprostate gland, which is globular and not cylindrical as in P. longum, P. tumidilum, P. medusae, and P. ophidum; (3 the size of the tribocytic organ 201-407 long, 183-495 wide, while is 138-270 long, 102-292 wide in P. medusae, and 138-270 long, 255 wide in P. ophidum; (4 the number of papillae in the tribocytic organ (18-20 in P. globulare and 16-18 in P. medusae, and 8 in P. ophidum. Specimens belonging to six other species of proterodiplostomes are recorded for the first time infecting the caiman, C. c. yacare in the Pantanal Mato-grossense, Brazil, namely: Proterodiplostomum medusae, P. tumidilum, Cystodiplostomum hollyi, Prolecithodiplostomum constrictum, Paradiplostomum abbreviatum, and Herpetodiplostomum caimancola.

  14. Reduced salinity increases susceptibility of zooxanthellate jellyfish to herbicide toxicity during a simulated rainfall event

    International Nuclear Information System (INIS)

    Klein, Shannon G.; Pitt, Kylie A.; Carroll, Anthony R.

    2016-01-01

    Accurately predicting how marine biota are likely to respond to changing ocean conditions requires accurate simulation of interacting stressors, exposure regimes and recovery periods. Jellyfish populations have increased in some parts of the world and, despite few direct empirical tests, are hypothesised to be increasing because they are robust to a range of environmental stressors. Here, we investigated the effects of contaminated runoff on a zooxanthellate jellyfish by exposing juvenile Cassiopea sp. medusae to a photosystem II (PSII) herbicide, atrazine and reduced salinity conditions that occur following rainfall. Four levels of atrazine (0ngL"−"1, 10ngL"−"1, 2μgL"−"1, 20μgL"−"1) and three levels of salinity (35 ppt, 25 ppt, 17 ppt) were varied, mimicking the timeline of light, moderate and heavy rainfall events. Normal conditions were then slowly re-established over four days to mimic the recovery of the ecosystem post-rain and the experiment continued for a further 7 days to observe potential recovery of the medusae. Pulse-amplitude modulated (PAM) chlorophyll fluorescence, growth and bell contraction rates of medusae were measured. Medusae exposed to the combination of high atrazine and lowest salinity died. After 3 days of exposure, bell contraction rates were reduced by 88% and medusae were 16% smaller in the lowest salinity treatments. By Day 5 of the experiment, all medusae that survived the initial pulse event began to recover quickly. Although atrazine decreased YII under normal salinity conditions, YII was further reduced when medusae were exposed to both low salinity and atrazine simultaneously. Atrazine breakdown products were more concentrated in jellyfish tissues than atrazine at the end of the experiment, suggesting that although bioaccumulation occurred, atrazine was metabolised. Our results suggest that reduced salinity may increase the susceptibility of medusae to herbicide exposure during heavy rainfall events. - Highlights:

  15. Predicting the Presence of Scyphozoan Jellyfish in the Gulf of Mexico Using a Biophysical Model

    Science.gov (United States)

    Aleksa, K. T.; Nero, R. W.; Wiggert, J. D.; Graham, W. M.

    2016-02-01

    The study and quantification of jellyfish (cnidarian medusae and ctenophores) is difficult due to their fragile body plan and a composition similar to their environment. The development of a predictive biophysical jellyfish model would be the first of its kind for the Gulf of Mexico and could provide assistance in ecological research and human interactions. In this study, the collection data of two scyphozoan medusae, Chrysaora quinquecirrha and Aurelia spp., were extracted from SEAMAP trawling surveys and were used to determine biophysical predictors for the presence of large jellyfish medusae in the Gulf of Mexico. Both in situ and remote sensing measurements from 2003 to 2013 were obtained. Logistic regressions were then applied to 27 biophysical parameters derived from these data to explore and determine significant predictors for the presence of medusae. Significant predictors identified by this analysis included water temperature, chlorophyll a, turbidity, distance from shore, and salinity. Future application for this model include foraging assessment of gelatinous predators as well as possible near real time monitoring of the distribution and movement of these medusae in the Gulf of Mexico.

  16. Life-history stages of the jellyfish Aurelia aurita - towards a demographic understanding of jellyfish blooms

    DEFF Research Database (Denmark)

    Goldstein, Josephine

    2017-01-01

    Jellyfish blooms are conspicuous demographic events that have received increasing attention by the public and the scientific community over the last decades due to their negative impact on fisheries, tourism and other human industries. Several aspects of the complex life cycles of the jellyfish......, including frequent mass occurrence of A. aurita medusae in temperate Danish waters. The present novel data show for instance, that jellyfish blooms of A. aurita are strongly affected by food availability and corresponding shifts between asexually reproducing benthic polyps and sexually reproducing pelagic...... medusae, which might be highly representative for the majority of bloom-forming jellyfish species. Findings further indicate that seasonal shrinkage and subsequent disappearance of A. aurita medusae is rather driven by food limitation than by a trade-off between sexual reproduction and metabolic...

  17. Sex determination and differentiation in Aurelia sp.1: the absence of temperature dependence

    Science.gov (United States)

    Liu, Chunsheng; Gu, Zhifeng; Xing, Mengxin; Sun, Yun; Chen, Siqing; Chen, Zhaoting

    2018-03-01

    Cnidarians, being regarded as `basal' metazoan animals, are considered to have relatively high plasticity in terms of sex reversal. In this study we used an experimental approach to demonstrate sexual differentiation and plasticity in benthic polyps and pelagic medusae of Aurelia sp.1 maintained at different temperatures. Results indicated that in Aurelia sp.1, sex differentiation has been determined at the polyp stage and that all medusae originating from a given polyp are, phenotypically, of the same sex. In addition, the sex of polyps budding from the same clone (either male or female) at different temperatures appears to be the same as that of the parent. The sex of medusae that had originated from a known-sex polyp was observed to remain the same as that of the parent, irrespective of differences in strobilation or rearing temperatures. These results indicate that the mechanism of sex determination of Aurelia sp.1. is not influenced by prevailing temperature regimes. A comparison of variability in terms of sexual plasticity of Aurelia sp.1 with that of Hydrozoa and Anthozoa suggests that species characterized by a free-swimming medusa life stage have a high dispersal potential, which probably results in a lower rate of sex reversal.

  18. Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish

    DEFF Research Database (Denmark)

    Garm, Anders Lydik; Mori, S.

    2009-01-01

    Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a s......Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...... when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take...

  19. Perseus

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    (abbrev. Per, gen. Persei; area 615 sq. deg.) A northern constellation which lies between Andromeda and Auriga, and culminates at midnight in early November. It is named after the hero in Greek mythology who beheaded the Gorgon Medusa and rescued Andromeda from being sacrificed to the sea monster Cetus. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....

  20. Ecology, genetics, and biological control of invasive annual grasses in the Great Basin

    Science.gov (United States)

    Several annual grass species native to Eurasia, including cheatgrass (Bromus tectorum), red brome (B. rubens), and medusahead (Taeniatherum caput-medusae) have become invasive in the western USA. These invasive species degrade rangelands by compromising forage, outcompeting native flora, and exacerb...

  1. Fulltext PDF

    Indian Academy of Sciences (India)

    expressed in closed form? Anagrams of Wiiliam Burnside: I WARN DUMB LILIES. SIMILAR, BLUE WIND. I WILL SUM IN BREAD. MEDUSA ILL; WIN RIB. I WILL DREAM IN BUS. BILL; I MUSE INWARD. INLA W IS MULE BIRD. I DRAW IN SEMI-BULL. I WILL DUB SEMINAR. BILL; I MUSE DARWIN. I AM ILL; WIN RED BUS.

  2. The sensitivity theory for inertial confinement pellet fusion system

    International Nuclear Information System (INIS)

    Cai, Shaohui; Zhang, Yuquan.

    1986-01-01

    A sensitivity theory for inertial confinement pellet fusion system is developed based on a physical model similar to that embodied in the laser fusion code MEDUSA. The theory presented here can be an efficient tool for estimating the effects of many alternations in the data field. Our result is different from Greenspan's work in 1980. (author)

  3. Fulltext PDF

    Indian Academy of Sciences (India)

    earlier issue of Resonance. The Medusa and the Snail is a collection of essays that seem completely different - one could be on cloning, and the next on schizophrenia! But they all have a single common thread running through - each essay explores an aspect of 'selfness'. It is difficult to give you a sense of what I mean by ...

  4. Surrealist's Dreams and Classical Tradition

    Czech Academy of Sciences Publication Activity Database

    Bažant, Jan

    2015-01-01

    Roč. 48, č. 1 (2015), s. 82-94 ISSN 0044-9008 Institutional support: RVO:67985955 Keywords : Medusa * snakes * surrealism Subject RIV: AB - History http://www.dejum.sav.sk/?language=sk§ion=magazine&id=98&textId=590&sub=study

  5. Pattern- and contrast-dependent visual response in the box jellyfish Tripedalia cystophora

    DEFF Research Database (Denmark)

    Garm, Anders; Hedal, Ida; Islin, Majken

    2013-01-01

    Cubomedusae possess a total of 24 eyes, some of which are structurally similar to vertebrate eyes. Accordingly, the medusae also display a range of light-guided behaviours including obstacle avoidance, diurnal activity patterns and navigation. Navigation is supported by spatial resolution and image...

  6. Thermal and Osmotic Tolerance of 'Irukandji' Polyps: Cubozoa; Carukia barnesi.

    Directory of Open Access Journals (Sweden)

    Robert Courtney

    Full Text Available This research explores the thermal and osmotic tolerance of the polyp stage of the Irukandji jellyfish Carukia barnesi, which provides new insights into potential polyp habitat suitability. The research also targets temperature, salinity, feeding frequency, and combinations thereof, as cues for synchronous medusae production. Primary findings revealed 100% survivorship in osmotic treatments between 19 and 46‰, with the highest proliferation at 26‰. As salinity levels of 26‰ do not occur within the waters of the Great Barrier Reef or Coral Sea, we conclude that the polyp stage of C. barnesi is probably found in estuarine environments, where these lower salinity conditions commonly occur, in comparison to the medusa stage, which is oceanic. Population stability was achieved at temperatures between 18 and 31°C, with an optimum temperature of 22.9°C. We surmise that C. barnesi polyps may be restricted to warmer estuarine areas where water temperatures do not drop below 18°C. Asexual reproduction was also positively correlated with feeding frequency. Temperature, salinity, feeding frequency, and combinations thereof did not induce medusae production, suggesting that this species may use a different cue, possibly photoperiod, to initiate medusae production.

  7. Multi-dimensional free-electron laser simulation codes: a comparison study

    CERN Document Server

    Biedron, S G; Dejus, Roger J; Faatz, B; Freund, H P; Milton, S V; Nuhn, H D; Reiche, S

    2000-01-01

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

  8. Multi-dimensional free-electron laser simulation codes: a comparison study

    International Nuclear Information System (INIS)

    Biedron, S. G.; Chae, Y. C.; Dejus, R. J.; Faatz, B.; Freund, H. P.; Milton, S. V.; Nuhn, H.-D.; Reiche, S.

    1999-01-01

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL

  9. The APS SASE FEL: modeling and code comparison

    International Nuclear Information System (INIS)

    Biedron, S. G.

    1999-01-01

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL

  10. Searching for microbial biological control candidates for invasive grasses: coupling expanded field research with strides in biotechnology and grassland restoration

    Science.gov (United States)

    Highly invasive grasses (e.g. Bromus spp., Pennisetum ciliare, Taeniatherum caput-medusae) are largely unabated in much of the arid Western U.S., despite more than 70 years of control attempts with a wide array of tools and management practices. The development and sustained integration of new appro...

  11. A Working Ranch with an Effective Medusahead Management Program

    Science.gov (United States)

    Since 2005, rancher Ben McGough, owner of the Circle Bar Ranch in Mitchell, Oregon, has been working with USDA-ARS rangeland ecologist Roger Sheley to implement EBIPM on the ranch. More than 600 acres were infested with medusahead (Taeniatherum caput-medusae) when they began working together. We de...

  12. Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology

    Directory of Open Access Journals (Sweden)

    Nicholas E.C. Fleming

    2015-07-01

    Full Text Available Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ13C and δ15N stable isotope values, we examined: (1 whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2 Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3 When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ15N (trophic position were evident between all three species, with size-based and temporal shifts in δ15N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous

  13. The value of small habitat islands for the conservation of genetic variability in a steppe grass species

    Science.gov (United States)

    Wódkiewicz, Maciej; Dembicz, Iwona; Moysiyenko, Ivan I.

    2016-10-01

    The habitat loss and fragmentation due to agricultural land-conversion affected the steppe throughout its range. In Ukraine, 95% of steppe was destroyed in the last two centuries. Remaining populations are confined to few refuges, like nature reserves, loess ravines, and kurgans (small burial mounds), the latter being often subject to destruction by archeological excavations. Stipa capillata L. is a typical grass species of Eurasian steppes and extrazonal dry grasslands, that was previously used as a model species in studies on steppe ecology. The aim of our research was to assess genetic diversity of S. capillata populations within different types of steppe refuges (loess ravines, biosphere reserve, kurgan) and to evaluate the value of the latter group for the preservation of genetic diversity in the study species. We assessed genetic diversity of 266 individuals from 15 populations (nine from kurgans, three from loess ravines and three from Askania-Nova Biosphere Reserve) with eight Universal Rice Primers (URPs). Studied populations showed high intra-population variability (I: 0.262-0.419, PPB: 52.08-82.64%). Populations from kurgans showed higher genetic differentiation (ΦST = 0.247) than those from loess ravines (ΦST = 0.120) and the biosphere reserve (ΦST = 0.142). Although the diversity metrics were to a small extent lower for populations from kurgans than from larger refugia we conclude that all studied populations of the species still preserve high genetic variability and are valuable for protection. To what extent this pattern holds true under continuous fragmentation in the future must be carefully monitored.

  14. Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology.

    Science.gov (United States)

    Fleming, Nicholas E C; Harrod, Chris; Newton, Jason; Houghton, Jonathan D R

    2015-01-01

    Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ (13)C and δ (15)N stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ (15)N (trophic position) were evident between all three species, with size-based and temporal shifts in δ (15)N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions

  15. Upside-Down but Headed in the Right Direction: Review of the Highly Versatile Cassiopea xamachana System

    Directory of Open Access Journals (Sweden)

    Aki H. Ohdera

    2018-04-01

    Full Text Available The upside-down jellyfish Cassiopea xamachana (Scyphozoa: Rhizostomeae has been predominantly studied to understand its interaction with the endosymbiotic dinoflagellate algae Symbiodinium. As an easily culturable and tractable cnidarian model, it is an attractive alternative to stony corals to understanding the mechanisms driving establishment and maintenance of symbiosis. Cassiopea is also unique in requiring the symbiont in order to complete its transition to the adult stage, thereby providing an excellent model to understand symbiosis-driven development and evolution. Recently, the Cassiopea research system has gained interest beyond symbiosis in fields related to embryology, climate ecology, behavior, and more. With these developments, resources including genomes, transcriptomes, and laboratory protocols are steadily increasing. This review provides an overview of the broad range of interdisciplinary research that has utilized the Cassiopea model and highlights the advantages of using the model for future research.

  16. A multigroup treatment of radiation transport

    International Nuclear Information System (INIS)

    Tahir, N.A.; Laing, E.W.; Nicholas, D.J.

    1980-12-01

    A multi-group radiation package is outlined which will accurately handle radiation transfer problems in laser-produced plasmas. Bremsstrahlung, recombination and line radiation are included as well as fast electron Bremsstrahlung radiation. The entire radiation field is divided into a large number of groups (typically 20), which diffuse radiation energy in real space as well as in energy space, the latter occurring via electron-radiation interaction. Using this model a radiation transport code will be developed to be incorporated into MEDUSA. This modified version of MEDUSA will be used to study radiative preheat effects in laser-compression experiments at the Central Laser Facility, Rutherford Laboratory. The model is also relevant to heavy ion fusion studies. (author)

  17. The homeobox gene Msx in development and transdifferentiation of jellyfish striated muscle.

    Science.gov (United States)

    Galle, Sabina; Yanze, Nathalie; Seipel, Katja

    2005-01-01

    Bilaterian Msx homeobox genes are generally expressed in areas of cell proliferation and in association with multipotent progenitor cells. Likewise, jellyfish Msx is expressed in progenitor cells of the developing entocodon, a cell layer giving rise to the striated and smooth muscles of the medusa. However, in contrast to the bilaterian homologs, Msx gene expression is maintained at high levels in the differentiated striated muscle of the medusa in vivo and in vitro. This tissue exhibits reprogramming competence. Upon induction, the Msx gene is immediately switched off in the isolated striated muscle undergoing transdifferentiation, to be upregulated again in the emerging smooth muscle cells which, in a stem cell like manner, undergo quantal cell divisions producing two cell types, a proliferating smooth muscle cell and a differentiating nerve cell. This study indicates that the Msx protein may be a key component of the reprogramming machinery responsible for the extraordinary transdifferentation and regeneration potential of striated muscle in the hydrozoan jellyfish.

  18. El plancton del Atlántico suroeste: dinamica y ecología

    Directory of Open Access Journals (Sweden)

    Angeles Alvariño

    1980-12-01

    Full Text Available Plankton was collected in Nov.-Dec. 1972, during the Cato-6 Expedition (R/VMelville. Distribution of Siphonophores and Medusae and ecological implications pointed out by these organisms are discussea. 25 species of Siphonophorae were obtained corresponding to tropical, temperate, and Antarctic Subantarctic categories. 5 species of Medusae appeared , showing the peculiar erratic distribution typical of these organisms. Faunistic data are presented in tables and maps. Effects of Brazil, Falkland Currents and upwelling, centers appear well defined by the distribution of the siphonophores. Cosmopolitan siphonophores, typical of temperate and warm waters inhabited a band (zone of Rio Grande rise between the southernmost and northernmost progressions of Brazil and Falkland Currents. These populations are carried toward South-american coasts by the anticyclonic circulation of the Central South Atlantic, forming a convergence; and a divergence towards the north is responsible for development of upwelling systems

  19. In-field radon measurement in water: a novel approach

    International Nuclear Information System (INIS)

    Talha, S.A.; Meijer, R.J. de; Lindsay, R.; Newman, R.T.; Maleka, P.P.; Hlatshwayo, I.N.

    2010-01-01

    This paper presents a novel approach of measuring radon in-water in the field by inserting a MEDUSA gamma-ray detector into a 210 L or 1000 L container. The experimental measurements include investigating the effect of ambient background gamma-rays on in-field radon measurement, calibrating the detector efficiency using several amounts of KCl salt dissolved in tap water, and measuring radon in borehole water. The results showed that there is fairly good agreement between the field and laboratory measurements of radon in water, based on measurements with Marinelli beakers on a HPGe detector. The MDA of the method is 0.5 Bq L -1 radon in-water. -- Research highlights: →Radon-in-water, large volume container, in-field measurements, MEDUSA gamma-ray detection system.

  20. MED101: a laser-plasma simulation code. User guide

    International Nuclear Information System (INIS)

    Rodgers, P.A.; Rose, S.J.; Rogoyski, A.M.

    1989-12-01

    Complete details for running the 1-D laser-plasma simulation code MED101 are given including: an explanation of the input parameters, instructions for running on the Rutherford Appleton Laboratory IBM, Atlas Centre Cray X-MP and DEC VAX, and information on three new graphics packages. The code, based on the existing MEDUSA code, is capable of simulating a wide range of laser-produced plasma experiments including the calculation of X-ray laser gain. (author)

  1. Pegasus

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    (the Winged Horse; abbrev. Peg, gen. Pegasi; area 1121 sq. deg.) A northern constellation that extends from Cygnus, Lacerta and Andromeda almost to the celestial equator, and culminates at midnight in early September. It is named after the winged horse in Greek mythology that sprang from the body of Medusa, the Gorgon, when she was beheaded by Perseus, and later was tamed by the hero Bellerophon. ...

  2. Fungus diseases of poplar that pose a threat to Italy

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, E.; Cellerino, G.P.; Garibaldi, A.

    1981-01-01

    European Economic Community Directive No. 7793 on the exchange of, and trade in, plant material between member countries specified Hypoxylon mammatum, Mycosphaerella populorum, Melampsora medusae and Xanthomonas populi as the causal agents of serious poplar diseases the introduction of which into Italy should be avoided. Information is given on the geographic distribution, morphology and biology of the four pathogens, together with notes on the symptoms of attack, host plants and damage caused. Control measures to avoid their introduction and spread are suggested.

  3. Venous infraction of developmental venous anomaly: A case report with perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Youn; Kim, Hye Jeong; Hyun, Su Jeong; Kim, Hee Yeong; Kim, Han Myun; Hwang, Ji Young; Hong, Hye Suk; Woo, Ji Young; Yang, Ik [Dept. of Radiology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Eun Soo [Dept. of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of)

    2017-06-15

    Developmental venous anomaly (DVA) is a common congenital venous malformation characterized by dilated medullary veins in caput medusa configuration and a draining vein. Despite the high incidence of DVAs, they are benign anatomic variations and rarely cause symptoms. Here, we report computed tomography and magnetic resonance imaging findings with perfusion images of acute infarction from underlying DVA in a 63-year-old female patient who presented with acute onset of neurologic symptoms and recovered without any neurologic deficit.

  4. Warburg, Shakespeare e la prima impresa

    Directory of Open Access Journals (Sweden)

    Alice Barale

    2012-12-01

    Full Text Available With his fight against the sea monster Medusa, Perseus embodies for Warburg the “world-directed energy”. Warburg's “energetic  aesthetics” could be interpreted then as nothing but another version of the hypertrophic, despotic subject Ferraris has often written about. We will show it that is not the case by considering the relationship that Warburg draws between Perseus and Hamlet.

  5. Computed tomographic reconstruction of beam profiles with a multi-wire chamber

    International Nuclear Information System (INIS)

    Alonso, J.R.; Tobias, C.A.; Chu, W.T.

    1979-03-01

    MEDUSA (MEdical Dose Uniformity SAmpler), a 16 plane multi-wire proportional chamber, has been built to accurately measure beam profiles. The large number of planes allows for reconstruction of highly detailed beam intensity structures by means of Fourier convolution reconstruction techniques. This instrument is being used for verification and tuning of the Bevalac radiotherapy beams, but has potential applications in many beam profile monitoring situations

  6. TECHNIQUES DE MYSTIFICATION DU SACRÉ DANS LA LITTÉRATURE MYTHOLOGISANTE DE LA GRÈCE ANTIQUE

    OpenAIRE

    Dr. Maria-Luiza Oancea (Dumitru)

    2008-01-01

    This paper entails the sacred mytification motif, a subject hardly debated, but extremely challenging, that we can identify in several myths and episodes of the ancient Greek mythology literature (Thanatos-Sisyphus myth, Sirens-Odysseus or Sirens-Orpheus myth, Polifem-Odysseus myth, Gorgo Medusa-Perseus myth, etc.). Our essay starts from the general thesis that a direct confrontation with the Sacred is essentially impossible, making the Sacred almost always manipulated (cf. R. Caillois, R. Gi...

  7. Il museo della scienza di Villa Farnesina

    Directory of Open Access Journals (Sweden)

    Francesca Salvemini

    2005-02-01

    Full Text Available Rappresentavano l’Astronomia le due logge romane del viridario di villa Farnesina con la Sala adiacente del Trionfo di Ercole: lo spazio, l’astrolabio zodiacale della Sala di Galatea - in testa le stelle dell’Orsa minore fatte di “sasso” da Medusa, Peruzzi nella biografia di Vasari - e il tempo, la meccanica dello gnomone solare del Trionfo di Cupido.

  8. Comparison of zooxanthellae densities from upside-down jellyfish, Cassiopea xamachana, across coastal habitats of The Bahamas

    OpenAIRE

    Stoner, Elizabeth W.; Sebilian, Serina S.; Layman, Craig A.

    2016-01-01

    Anthropogenic disturbances may drive jellyfish blooms, and previous studies have suggested this is the case for upside-down jellyfish (Cassiopea xamachana). Cassiopea were found to have higher mean zooxanthellae densities in human-impacted areas on Abaco Island, The Bahamas, suggesting that nutrient loading in impacted sites may be one factor driving zooxanthellate jellyfish blooms. Gut contents from Cassiopea medusae were positively correlated to zooxanthellae densities, indicating that hete...

  9. Measurement of Seafloor Deformation in the Marine Sector of the Campi Flegrei Caldera (Italy)

    Science.gov (United States)

    Iannaccone, Giovanni; Guardato, Sergio; Donnarumma, Gian Paolo; De Martino, Prospero; Dolce, Mario; Macedonio, Giovanni; Chierici, Francesco; Beranzoli, Laura

    2018-01-01

    We present an assessment of vertical seafloor deformation in the shallow marine sector of the Campi Flegrei caldera (southern Italy) obtained from GPS and bottom pressure recorder (BPR) data, acquired over the period April 2016 to July 2017 in the Gulf of Pozzuoli by a new marine infrastructure, MEDUSA. This infrastructure consists of four fixed buoys with GPS receivers; each buoy is connected by cable to a seafloor multisensor module hosting a BPR. The measured maximum vertical uplift of the seafloor is about 4.2 ± 0.4 cm. The MEDUSA data were then compared to the expected vertical displacement in the marine sector according to a Mogi model point source computed using only GPS land measurements. The results show that a single point source model of deformation is able to explain both the GPS land and seafloor data. Moreover, we demonstrate that a network of permanent GPS buoys represents a powerful tool to measure the seafloor vertical deformation field in shallow water. The performance of this system is comparable to on-land high-precision GPS networks, marking a significant achievement and advance in seafloor geodesy and extending volcano monitoring capabilities to shallow offshore areas (up to 100 m depth). The GPS measurements of MEDUSA have also been used to confirm that the BPR data provide an independent measure of the seafloor vertical uplift in shallow water.

  10. Aurelia labiata jellyfish in Roscoe Bay on the West Coast of Canada: Seasonal changes in adult bell diameter and mingling of juvenile and adult populations

    Science.gov (United States)

    Albert, David J.; Walsh, Michael L.

    2014-01-01

    The bell diameter of adult Aurelia labiata in Roscoe Bay increased from spring (April) to early summer (May/June) and decreased over the rest of the year (2009/2010). The increase in bell diameter in the spring would have been supported by the increase in zooplankton that occurs in the northeast Pacific at this time. Over the summer, bell diameter may have decreased because the food available/medusa would have been decreased by the arrival of a large number of juveniles and may have decreased further over the fall and winter when zooplankton levels are known to be low. Adults and juveniles were intermingled during 2010, 2011, and 2012. Correlations between the number of adults and number of juveniles obtained in individual net lifts across the entire bay and in different parts of the bay were all positive and most were statistically significant. In 2012, salinity in the entire water column of the west side of the bay dropped below 20 ppt in July and most medusae migrated to higher salinity in the east side of the bay, a distance of about 0.5 km. The mingling of adults and juveniles supports other evidence that adult Aurelia sp. medusae do not prey upon juveniles. The ability to withstand months with insufficient food and to inhibit preying on juveniles would contribute greatly to the survival of Aurelia sp. jellyfish.

  11. Identification and characterisation of a highly divergent geminivirus: evolutionary and taxonomic implications.

    Science.gov (United States)

    Bernardo, Pauline; Golden, Michael; Akram, Mohammad; Naimuddin; Nadarajan, Nagaswamy; Fernandez, Emmanuel; Granier, Martine; Rebelo, Anthony G; Peterschmitt, Michel; Martin, Darren P; Roumagnac, Philippe

    2013-10-01

    During a large scale "non a priori" survey in 2010 of South African plant-infecting single stranded DNA viruses, a highly divergent geminivirus genome was isolated from a wild spurge, Euphorbia caput-medusae. In addition to being infectious in E. caput-medusae, the cloned viral genome was also infectious in tomato and Nicotiana benthamiana. The virus, named Euphorbia caput-medusae latent virus (EcmLV) due to the absence of infection symptoms displayed by its natural host, caused severe symptoms in both tomato and N. benthamiana. The genome organisation of EcmLV is unique amongst geminiviruses and it likely expresses at least two proteins without any detectable homologues within public sequence databases. Although clearly a geminivirus, EcmLV is so divergent that we propose its placement within a new genus that we have tentatively named Capulavirus. Using a set of highly divergent geminiviruses genomes, it is apparent that recombination has likely been a primary process in the genus-level diversification of geminiviruses. It is also demonstrated how this insight, taken together with phylogenetic analyses of predicted coat protein and replication associated protein (Rep) amino acid sequences indicate that the most recent common ancestor of the geminiviruses was likely a dicot-infecting virus that, like modern day mastreviruses and becurtoviruses, expressed its Rep from a spliced complementary strand transcript. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Time-Dependent Simulation of Free-Electron Laser Amplifiers and Oscillators

    CERN Document Server

    Freund, H

    2005-01-01

    Time-dependent FEL simulations use a variety of techniques. Most simulations use a slowly varying envelope approximation (SVEA). One such technique assumes that the envelope varies only in z combined with a field representation as an ensemble of discrete harmonics, which is equivalent to a time-dependent simulation [1] but is computationally prohibitive. A second technique uses an SVEA in both in z and t [2]. The particles and fields are advanced in z using the same process as in steady-state simulations and then the time derivative describing slippage is applied. This is used in wiggler-averaged codes such as GINGER [3] and GENESIS [4]. We describe the inclusion of this technique in the non-wiggler-averaged code MEDUSA [5], which is applied to amplifiers and oscillators. MEDUSA differs from GINGER and GENESIS also in the way the field is treated. GINGER and GENESIS use a field solver and must explicitly propagate the field outside the wiggler oscillators. This is computationally intensive. MEDUSA uses a Gaus...

  13. Polyp Removal of a Bloom Forming Jellyfish, Aurelia coerulea, in Korean Waters and Its Value Evaluation

    Science.gov (United States)

    Yoon, Wonduk; Chae, Jinho; Koh, Byoung-Seol; Han, Changhoon

    2018-04-01

    Aurelia coerulea is a bloom forming jellyfish that first appeared before 1980 in the western and southern Korean seas and which has been blamed for huge economical losses in all fields of marine activities. As a preventive measure to reduce economical losses, polyp removal was undertaken at Lake Shihwa, Lake Saemangeum, and Masan Bay, Korea. In the course of efforts during 2 years to remove polyps, polyps were surveyed, quantified, and removed. In these areas, the initial total polyp abundance was 5.04 × 109 and 46.25% of them were removed; Lake Shihwa the highest rates of removal and Lake Saemangeum the lowest. These efforts to remove polyps prevented the appearance of 1.20 × 109 medusae, corresponding to 78.28 × 106 kg. The cost of polyp removal was evaluated and compared with that of medusae removal. The ratio between the cost of polyp removal and that of medusae removal ranged between 0.78-3.14%, indicating large cost savings for polyp removal undertakings. However, the effect of polyp removal varied from positive to none, and we assumed that the cleared surface for polyp removal, quantity of removed polyp, and existence of polyps' hotspots in neighboring areas were the causes of the non-effectiveness of polyp removal undertakings.

  14. Seasonality in polyps of a tropical cubozoan: A latina nr mordens.

    Directory of Open Access Journals (Sweden)

    Robert Courtney

    Full Text Available A latina nr mordens have been located in large predictable spawning aggregations near Osprey Reef in the Coral Sea eight to ten days after a full moon; however, polyps have never been located in-situ. The polyp stage contributes to the abundance of medusae through asexual reproduction and metamorphosis, and may influence the periodicity of medusae by metamorphosis of the polyp. To elucidate the relationship between medusae periodicity and polyp ecology, polyps were exposed to thermal and osmotic treatments in order to determine the theoretical environmental limits to their distribution. Maximum fecundity occurred in thermal treatments of 21 to 25ºC and the theoretical minimum thermal requirement for population stability was approximately 17ºC. Polyps were also exposed to five feeding regimes and fecundity was found to be positively correlated with feeding frequency. Thermal and osmotic variations did not induce metamorphosis in this species, however, reduced food did. The implications of asexual reproduction and cues for metamorphosis in relation to population dynamics of this species are discussed.

  15. Population dynamics and factors controlling somatic degrowth of the common jellyfish, Aurelia aurita, in a temperate semi-enclosed cove (Kertinge Nor, Denmark)

    DEFF Research Database (Denmark)

    Goldstein, Josephine; Riisgård, Hans Ulrik

    2016-01-01

    Life expectancy of the scyphomedusa Aurelia aurita seems closely linked to seasonal shrinkage, or somatic degrowth, which occurs synchronously with sexual reproduction in temperate regions. In the present study, the mechanisms controlling body mass losses and subsequent disappearance of medusae w...... reproduction. Seasonal variability in food supply, rather than energy allocation to reproduction, appears to shorten life spans of A. aurita medusae in temperate Danish waters.......Life expectancy of the scyphomedusa Aurelia aurita seems closely linked to seasonal shrinkage, or somatic degrowth, which occurs synchronously with sexual reproduction in temperate regions. In the present study, the mechanisms controlling body mass losses and subsequent disappearance of medusae......, mm), following the exponential relationship NL = 160.8 × e0.029d. The percentage of body mass made up by planulae ranged from 6 to 11 % in Kertinge Nor and 10 to 33 % in Great Belt. ≤15 % of total size-specific body mass losses were due to the release of planulae in Kertinge Nor, suggesting shortage...

  16. Higher-order harmonics coupling in different free-electron laser codes

    Science.gov (United States)

    Giannessi, L.; Freund, H. P.; Musumeci, P.; Reiche, S.

    2008-08-01

    The capability for simulation of the dynamics of a free-electron laser including the higher-order harmonics in linear undulators exists in several existing codes as MEDUSA [H.P. Freund, S.G. Biedron, and S.V. Milton, IEEE J. Quantum Electron. 27 (2000) 243; H.P. Freund, Phys. Rev. ST-AB 8 (2005) 110701] and PERSEO [L. Giannessi, Overview of Perseo, a system for simulating FEL dynamics in Mathcad, , in: Proceedings of FEL 2006 Conference, BESSY, Berlin, Germany, 2006, p. 91], and has been recently implemented in GENESIS 1.3 [See ]. MEDUSA and GENESIS also include the dynamics of even harmonics induced by the coupling through the betatron motion. In addition MEDUSA, which is based on a non-wiggler averaged model, is capable of simulating the generation of even harmonics in the transversally cold beam regime, i.e. when the even harmonic coupling arises from non-linear effects associated with longitudinal particle dynamics and not to a finite beam emittance. In this paper a comparison between the predictions of the codes in different conditions is given.

  17. Floating nurseries? Scyphozoan jellyfish, their food and their rich symbiotic fauna in a tropical estuary

    Directory of Open Access Journals (Sweden)

    José M. Riascos

    2018-06-01

    Full Text Available Background The anthropogenic modification of trophic pathways is seemingly prompting the increase of jellyfish populations at the expense of planktivorous fishes. However, gross generalizations are often made because the most basic aspects of trophic ecology and the diverse interactions of jellyfish with fishes remain poorly described. Here we inquire on the dynamics of food consumption of the medusoid stage of the scyphozoan jellyfish Stomolophus meleagris and characterize the traits and diversity of its symbiotic community. Methods S. meleagris and their associated fauna were sampled in surface waters between November 2015 and April 2017 in Málaga Bay, an estuarine system at the Colombian Pacific. Stomach contents of medusae were examined and changes in prey composition and abundance over time analysed using a multivariate approach. The associated fauna was identified and the relationship between the size of medusae and the size those organisms tested using least-square fitting procedures. Results The presence of S. meleagris medusa in surface waters was seasonal. The gut contents analysis revealed that algae, copepods and fish early life stages were the more abundant items, and PERMANOVA analysis showed that the diet differed within the seasons (P(perm = 0.001 but not between seasons (P(perm = 0.134. The majority of the collected medusae (50.4% were associated with individuals of 11 symbiotic species, 95.3% of them fishes, 3.1% crustaceans and 1.6% molluscs. Therefore, this study reports 10 previously unknown associations. The bell diameter of S. meleagris was positively related to the body sizes of their symbionts. However, a stronger fit was observed when the size relationship between S. meleagris and the fish Hemicaranx zelotes was modelled. Discussion The occurrence of S. meleagris was highly seasonal, and the observed patterns of mean body size through the seasons suggested the arrival of adult medusae to the estuary from adjacent

  18. Floating nurseries? Scyphozoan jellyfish, their food and their rich symbiotic fauna in a tropical estuary

    Science.gov (United States)

    Aguirre, Willington; Hopfe, Charlotte; Morales, Diego; Navarrete, Ángela; Tavera, José

    2018-01-01

    Background The anthropogenic modification of trophic pathways is seemingly prompting the increase of jellyfish populations at the expense of planktivorous fishes. However, gross generalizations are often made because the most basic aspects of trophic ecology and the diverse interactions of jellyfish with fishes remain poorly described. Here we inquire on the dynamics of food consumption of the medusoid stage of the scyphozoan jellyfish Stomolophus meleagris and characterize the traits and diversity of its symbiotic community. Methods S. meleagris and their associated fauna were sampled in surface waters between November 2015 and April 2017 in Málaga Bay, an estuarine system at the Colombian Pacific. Stomach contents of medusae were examined and changes in prey composition and abundance over time analysed using a multivariate approach. The associated fauna was identified and the relationship between the size of medusae and the size those organisms tested using least-square fitting procedures. Results The presence of S. meleagris medusa in surface waters was seasonal. The gut contents analysis revealed that algae, copepods and fish early life stages were the more abundant items, and PERMANOVA analysis showed that the diet differed within the seasons (P(perm) = 0.001) but not between seasons (P(perm) = 0.134). The majority of the collected medusae (50.4%) were associated with individuals of 11 symbiotic species, 95.3% of them fishes, 3.1% crustaceans and 1.6% molluscs. Therefore, this study reports 10 previously unknown associations. The bell diameter of S. meleagris was positively related to the body sizes of their symbionts. However, a stronger fit was observed when the size relationship between S. meleagris and the fish Hemicaranx zelotes was modelled. Discussion The occurrence of S. meleagris was highly seasonal, and the observed patterns of mean body size through the seasons suggested the arrival of adult medusae to the estuary from adjacent waters. The diet

  19. Floating nurseries? Scyphozoan jellyfish, their food and their rich symbiotic fauna in a tropical estuary.

    Science.gov (United States)

    Riascos, José M; Aguirre, Willington; Hopfe, Charlotte; Morales, Diego; Navarrete, Ángela; Tavera, José

    2018-01-01

    The anthropogenic modification of trophic pathways is seemingly prompting the increase of jellyfish populations at the expense of planktivorous fishes. However, gross generalizations are often made because the most basic aspects of trophic ecology and the diverse interactions of jellyfish with fishes remain poorly described. Here we inquire on the dynamics of food consumption of the medusoid stage of the scyphozoan jellyfish Stomolophus meleagris and characterize the traits and diversity of its symbiotic community. S. meleagris and their associated fauna were sampled in surface waters between November 2015 and April 2017 in Málaga Bay, an estuarine system at the Colombian Pacific. Stomach contents of medusae were examined and changes in prey composition and abundance over time analysed using a multivariate approach. The associated fauna was identified and the relationship between the size of medusae and the size those organisms tested using least-square fitting procedures. The presence of S. meleagris medusa in surface waters was seasonal. The gut contents analysis revealed that algae, copepods and fish early life stages were the more abundant items, and PERMANOVA analysis showed that the diet differed within the seasons ( P (perm)  = 0.001) but not between seasons ( P (perm)  = 0.134). The majority of the collected medusae (50.4%) were associated with individuals of 11 symbiotic species, 95.3% of them fishes, 3.1% crustaceans and 1.6% molluscs. Therefore, this study reports 10 previously unknown associations. The bell diameter of S. meleagris was positively related to the body sizes of their symbionts. However, a stronger fit was observed when the size relationship between S. meleagris and the fish Hemicaranx zelotes was modelled. The occurrence of S. meleagris was highly seasonal, and the observed patterns of mean body size through the seasons suggested the arrival of adult medusae to the estuary from adjacent waters. The diet of S. meleagris in the study

  20. Conservation state of populations of rare plant species in highly transformed meadow steppes of Southern Opillya

    Directory of Open Access Journals (Sweden)

    I. I. Dmytrash-Vatseba

    2016-09-01

    Full Text Available Degradation of natural habitats causes rapid extinction of rare plant populations. The diversity of rare plant species in the meadow steppes of Southern Opillya (Western Ukraine depends strongly on patch area, pasture digression of vegetation and a variety of eco-coenotical conditions. The main threats for the rare components of the meadow steppe flora are reduction of habitat and overgrazing. Spatial connections between sites are unable to support a constant rare plant population. The analysis of the composition of rare plant meadow-steppe species indicated that habitats with similar rare species composition usually have similar parameters of area, stages of pasture digression and eco-coenotical conditions. Spatial connectivity of patches does not ensure species similarity of rare components of the flora. Rare plant species were grouped according to their preferences for habitat , area and condition. In small patches subject to any stage of pasture digression grow populations of Adonis vernalis L., Pulsatilla patens (L. Mill., P. grandis Wender., Stipa capillata L., S. рennata L., Chamaecytisus blockianus (Pawł. Klásková etc. On the contrary, populations of other species (Carlina onopordifolia Besser. ex Szafer., Kuecz. et Pawł., Adenophora liliifolia (L. Ledeb. ex A. DC., Crambe tataria Sebeók, Euphorbia volhynica Besser ex Racib., Stipa tirsa Stev. etc. prefer large habitats, not changed by pasture digression. Prevention of reduction of rare species diversity requires preservation (also extension of patch area and regulation of grazing intensity.

  1. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods

    Directory of Open Access Journals (Sweden)

    Rafal Cupek

    2016-11-01

    Full Text Available Objectives : Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. Material and methods : This paper focus on a computer aided diagnostic system that was developed within joint Polish–Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner’s experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. Results : The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Conclusions : Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner’s experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an

  2. Radon generation and transport in and around a gold mine tailings dam in South Africa

    International Nuclear Information System (INIS)

    Speelman, W.J.; Lindsay, R.; Newman, R.T.; Meijer, R.J. de

    2006-01-01

    Naturally Occurring Radioactive Material (N.O.R.M.) occurs in most soil and rock, and by mining and mineral processing, some of the radionuclides are significantly enhanced. An in-situ gamma-ray detector called M.E.D.U.S.A., has been used to produce a map of relative activity concentrations in a gold mine tailings dam on the Witwatersrand in South Africa. A CsI(Na) scintillation detector is used in this system. M.E.D.U.S.A. spectra obtained from the survey were analyzed using the Full-Spectrum Analysis (F.S.A.) procedure to compute the 40 K, 238 U and 232 Th activity concentrations. The activity concentrations are used with global positioning data (G.P.S.) to produce the concentration maps. A hyper-pure germanium gamma-ray detector (Hp Ge) was used to measure gamma-rays from the naturally occurring nuclides for soil samples taken at different points on the site to calibrate the M.E.D.U.S.A. system. Radon soil gas measurements were performed at certain points on the mine tailings with a continuous radon monitor; R.A.D.7, and emanation coefficients were measured with electret technology. These parameters have been combined with the activity concentrations to obtain an average radon exhalation rate of about 0.1 Bq.m -2 .s -1 (with an uncertainty of about 20%) from the tailings dam. The purpose of the study is to also review and develop a mathematical model for radon activity concentration predictions in gold mine dumps. (authors)

  3. Seasonal variation of macromedusae (Cnidaria at North Bay, Florianópolis, southern Brazil

    Directory of Open Access Journals (Sweden)

    Miodeli Nogueira Júnior

    2010-06-01

    Full Text Available Seasonal variation of large medusae abundance and biomass was studied in the North Bay, Santa Catarina, southern Brazil (27°30'S, 48° 32'W, from February to December 2005. Collecting was conducted seasonally with the help of fishing bottom trawl in 30-minute sections (12 in summer, 18 in each of the remaining seasons in six stations, totaling 66 samples. Eight species were found: the hydrozoans Aequorea sp., Olindias sambaquiensis Müller, 1861, and Rhacostoma atlantica L. Agassiz, 1850; the cubozoans Chiropsalmus quadrumanus (Müller, 1859 and Tamoya haplonema Müller, 1859, and the scyphozoans Aurelia sp., Chrysaora lactea Eschscholtz, 1829 and Lychnorhiza lucerna Haeckel, 1880. Capture rates were low, up to 38 indiv. ha-1, and only ~47% of the samples were positive for jellyfish, comprising 206 individuals. Medusae abundance and species richness clearly changed from one season to another, but did not vary between the sites. Higher species richness (7 out of 8 and greater abundances were recorded during the fall (~60% and 72% of all medusae individuals and biomass respectively. Specific frequency of capture varied from 1.5 to 29% and C. lactea was the only species found in more than 25% of the samples. The three most common species dominated in different periods of the year: C. lactea during fall (78% of individuals and 60% of biomass, R. atlantica during winter (90% of individuals and 17% of biomass, and O. sambaquiensis in spring (78% of individuals and 40% of biomass. Only two individuals were caught during summer, one C. lactea and one R. atlantica. The results offer a general picture of the distribution of the macromedusae in the North Bay, but a continuous monitoring is desirable for a more detailed knowledge on the jellyfish dynamics in the Brazilian coastal waters.

  4. Feeding behaviour of the hydromedusa Aequorea vitrina

    Directory of Open Access Journals (Sweden)

    Hans Ulrik RiisgÅrd

    2007-06-01

    Full Text Available The prey-capture mechanism of the hydromedusa Aequorea vitrina was studied by means of laboratory video-microscope observations. In stagnant water A. vitrina remains stationary with its very long (about 4x bell diameter marginal tentacles motionless hanging down in the water, ready for ambush capture of prey organisms that collide with the tentacles. A. vitrina was found to be efficient at capturing brine shrimps (Artemia salina, less efficient at capturing rotifers (Brachionus plicatilis, and very inefficient at capturing copepods (Acartia tonsa. The initial hauling up of an extended marginal tentacle with an adhering prey is fast (>10 mm s-1. Both the bell margin and the mouth move towards each other so that the captured prey can be transferred from the tentacle to the elongated mouth-lips to be further transported into the mouth and stomach. It takes about 20 s from when an Artemia prey organism encounters a tentacle until it is transferred to the mouth-lips. The subsequent digestion in the stomach takes about 30 min. When A. vitrina encounters a jellyfish-prey (a small medusa of Aurelia aurita, it starts to swim in order to adhere the relatively big prey to its mouth-lips. Then A. vitrina opens its mouth wide to swallow the captured medusa, a process which takes about 15 to 20 min. The subsequent digestion takes 2 to 3 h. Field observations of undisturbed A. vitrina made by snorkelling in the Limfjord (Denmark revealed that the feeding behaviour was similar to that observed in the laboratory in stagnant water. It is concluded that A. vitrina is an ambush-predator, and not a cruising-predatory medusa as previously suggested.

  5. Ontogeny reversal and phylogenetic analysis of Turritopsis sp.5 (Cnidaria, Hydrozoa, Oceaniidae, a possible new species endemic to Xiamen, China

    Directory of Open Access Journals (Sweden)

    Jun-yuan Li

    2018-01-01

    Full Text Available Ontogeny reversal, as seen in some cnidarians, is an unprecedented phenomenon in the animal kingdom involving reversal of the ordinary life cycle. Three species of Turritopsis have been shown to be capable of inverted metamorphosis, a process in which the pelagic medusa transforms back into a juvenile benthic polyp stage when faced with adverse conditions. Turritopsis sp.5 is a species of Turritopsis collected from Xiamen, China which presents a similar ability, being able to reverse its life cycle if injured by mechanical stress. Phylogenetic analysis based on both 16S rDNA and cytochrome c oxidase subunit I (COI genetic barcodes shows that Turritopsis sp.5 is phylogenetically clustered in a clade separate from other species of Turritopsis. The genetic distance between T. sp.5 and the Japanese species T. sp.2 is the shortest, when measured by the Kimura 2-Parameter metric, and the distance to the New Zealand species T. rubra is the largest. An experimental assay on the induction of reverse development in this species was initiated by cutting medusae into upper and lower parts. We show, for the first time, that the two dissected parts have significantly different potentials to transform into polyps. Also, a series of morphological changes of the reversed life cycle can be recognised, including medusa stage, contraction stage I, contraction stage II, cyst, cyst with stolons, and polyp. The discovery of species capable of reverse ontogeny caused by unfavorable conditions adds to the available systems with which to study the cell types that contribute to the developmental reversal and the molecular mechanisms of the directional determination of ontogeny.

  6. How Well Can We Detect Lineage-Specific Diversification-Rate Shifts? A Simulation Study of Sequential AIC Methods.

    Science.gov (United States)

    May, Michael R; Moore, Brian R

    2016-11-01

    Evolutionary biologists have long been fascinated by the extreme differences in species numbers across branches of the Tree of Life. This has motivated the development of statistical methods for detecting shifts in the rate of lineage diversification across the branches of phylogenic trees. One of the most frequently used methods, MEDUSA, explores a set of diversification-rate models, where each model assigns branches of the phylogeny to a set of diversification-rate categories. Each model is first fit to the data, and the Akaike information criterion (AIC) is then used to identify the optimal diversification model. Surprisingly, the statistical behavior of this popular method is uncharacterized, which is a concern in light of: (1) the poor performance of the AIC as a means of choosing among models in other phylogenetic contexts; (2) the ad hoc algorithm used to visit diversification models, and; (3) errors that we reveal in the likelihood function used to fit diversification models to the phylogenetic data. Here, we perform an extensive simulation study demonstrating that MEDUSA (1) has a high false-discovery rate (on average, spurious diversification-rate shifts are identified [Formula: see text] of the time), and (2) provides biased estimates of diversification-rate parameters. Understanding the statistical behavior of MEDUSA is critical both to empirical researchers-in order to clarify whether these methods can make reliable inferences from empirical datasets-and to theoretical biologists-in order to clarify the specific problems that need to be solved in order to develop more reliable approaches for detecting shifts in the rate of lineage diversification. [Akaike information criterion; extinction; lineage-specific diversification rates; phylogenetic model selection; speciation.]. © The Author(s) 2016. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

  7. Timoides agassizii Bigelow, 1904, little-known hydromedusa (Cnidaria), appears briefly in large numbers off Oman, March 2011, with additional notes about species of the genus Timoides.

    Science.gov (United States)

    Purushothaman, Jasmine; Kharusi, Lubna Al; Mills, Claudia E; Ghielani, Hamed; Marzouki, Mohammad Al

    2013-12-11

    A bloom of the hydromedusan jellyfish, Timoides agassizii, occurred in February 2011 off the coast of Sohar, Al Batinah, Sultanate of Oman, in the Gulf of Oman. This species was first observed in 1902 in great numbers off Haddummati Atoll in the Maldive Islands in the Indian Ocean and has rarely been seen since. The species appeared briefly in large numbers off Oman in 2011 and subsequent observation of our 2009 samples of zooplankton from Sohar revealed that it was also present in low numbers (two collected) in one sample in 2009; these are the first records in the Indian Ocean north of the Maldives. Medusae collected off Oman were almost identical to those recorded previously from the Maldive Islands, Papua New Guinea, the Marshall Islands, Guam, the South China Sea, and Okinawa. T. agassizii is a species that likely lives for several months. It was present in our plankton samples together with large numbers of the oceanic siphonophore Physalia physalis only during a single month's samples, suggesting that the temporary bloom off Oman was likely due to the arrival of mature, open ocean medusae into nearshore waters. We see no evidence that T. agassizii has established a new population along Oman, since if so, it would likely have been present in more than one sample period. We are unable to deduce further details of the life cycle of this species from blooms of many mature individuals nearshore, about a century apart. Examination of a single damaged T. agassizii medusa from Guam, calls into question the existence of its congener, T. latistyla, known only from a single specimen.

  8. Radon generation and transport in and around a gold mine tailings dam in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Speelman, W.J.; Lindsay, R. [Western Cape Univ., Dept. of Physics (South Africa); Newman, R.T. [IThemba LABS, Somerset West (South Africa); Meijer, R.J. de [Nuclear Geophysics Division (NGD), KVI, Rijksuniversiteit Groningen (Netherlands)

    2006-07-01

    Naturally Occurring Radioactive Material (N.O.R.M.) occurs in most soil and rock, and by mining and mineral processing, some of the radionuclides are significantly enhanced. An in-situ gamma-ray detector called M.E.D.U.S.A., has been used to produce a map of relative activity concentrations in a gold mine tailings dam on the Witwatersrand in South Africa. A CsI(Na) scintillation detector is used in this system. M.E.D.U.S.A. spectra obtained from the survey were analyzed using the Full-Spectrum Analysis (F.S.A.) procedure to compute the {sup 40}K, {sup 238}U and {sup 232}Th activity concentrations. The activity concentrations are used with global positioning data (G.P.S.) to produce the concentration maps. A hyper-pure germanium gamma-ray detector (Hp Ge) was used to measure gamma-rays from the naturally occurring nuclides for soil samples taken at different points on the site to calibrate the M.E.D.U.S.A. system. Radon soil gas measurements were performed at certain points on the mine tailings with a continuous radon monitor; R.A.D.7, and emanation coefficients were measured with electret technology. These parameters have been combined with the activity concentrations to obtain an average radon exhalation rate of about 0.1 Bq.m{sup -2}.s{sup -1} (with an uncertainty of about 20%) from the tailings dam. The purpose of the study is to also review and develop a mathematical model for radon activity concentration predictions in gold mine dumps. (authors)

  9. El mito de Perseo en los mosaicos hispanorromanos : particularidades hispanas

    Directory of Open Access Journals (Sweden)

    Guadalupe López Monteagudo

    1998-01-01

    Full Text Available Análisis iconográfico de las distintas fases del mito de Perseo en ios mosaicos romanos, siguiendo las fuentes literarias - Dánae recibiendo la lluvia de oro, llegada de Dánae con el niño Perseo a las costas de Seripfios, Perseo dando muerte a la medusa volviendo la cabeza al escudo de Atfienea, llegada del tiéroe volando ai lugar donde se fiallaba expuesta Andrómeda, Perseo vencedor de la medusa y del kethos, Perseo contemplando a Andrómeda encadenada a la roca, el gorgoneion en el centro de un escudo de triángulos curvilíneos o de escamas en alusión a la égida o ai escudo de Atlienea - y las creaciones artísticas típicamente romanas - Perseo liberando a Andrómeda y Perseo y Andrómeda contemplando la cabeza de la medusa en el agua - con especial atención al tratamiento iconográfico y alegórico de los ejemplares hispanos.Iconograpfíical analysis of the Perseus' mytfi related on the román mosaics, througfi the literary sources - Danae and the goiden rain, Danae and Perseus arriving at Seriphos' coast, Perseus cutting de Medusa's head and turning back his head toward Athenea's shield, Perseus' arrival fiying on the site where Andrómeda is exposed against the rock, the hero hoiding the gorgoneion in the raised hand over kethos, the mude contemplation of the giri's beauty, Gorgon's head at centre of shield of lozenges or imbhcation pattern - and the original figured representations created by román art - Perseus helps Andrómeda step down from the cliff where she was chained and the two lovers seatted on a rock with the gorgoneion held overhead to reflect in the water - with a special emphasis in the iconographical variations and symbolic significance of the spanish patterns.

  10. [Conversations with the Sphinx. Images of Greek myth in Freud's collection].

    Science.gov (United States)

    Burke, Janine

    2006-01-01

    In Freud's art collection, the myth of Oedipus, a central tenet of psychoanalysis, is represented by several Greek statues and vases, as well as a reproduction of Ingres' painting. Originally a protective male Egyptian deity, in Greek myth, the Sphinx was female and associated with death. In addition, Freud had sculptures of Medusa the Gorgon, a terrifying winged female, and of provocative Baubo, both also figuring in his writings. By describing these works of art and some of their mythological ramifications, the author suggests that they represented aspects of feminity not really covered by Freud's theories.

  11. Gaze and power. A post-structuralist interpretation on Perseus’ myth

    Directory of Open Access Journals (Sweden)

    Olaya Fernández Guerrero

    2015-12-01

    Full Text Available Gaze hierarchizes, manages and labels reality. Then, according to Foucault, gaze can be understood as a practice of power. This paper is inspired by his theories, and it applies them to one of the most powerful symbolic spheres of Western culture: Greek Myths. Notions such as visibility, invisibility and panopticism bring new light into the story of Perseus and Medusa, and they enable a re-reading of this Myth focused on the different ways of power that emerge from the gaze.

  12. [Problems caused by poisonous tropical marine animals].

    Science.gov (United States)

    Lääveri, Tinja; Räisänen-Sokolowski, Anne; Jama, Timo

    2014-01-01

    A Finnish physician encounters problems caused by tropical marine animals either during her/his own travelling or while treating travelers who have returned home. Certain species of medusae and cone shells as well as the stings by some fish species are life-threateningly poisonous. A person stung or bitten by any of the most dangerous species must immediately be admitted to the hospital. Foreign material remaining in tissues after stings by echinoderms and spiky fish may cause problems months after the actual injury. The injuries become easily infected, and antimicrobial drug therapy must thus cover gram-negative rod-shaped bacteria as well.

  13. Increasing marketability and profitability of product line thru PATRAN and NASTRAN

    Science.gov (United States)

    Hyatt, Art

    1989-01-01

    Starting with the design objective the operational cycle life of the Swaging Tool was increased. To accomplish this increase in cycle life without increasing the size or weight of the tool would be engineering achievement. However, not only was the operational cycle life increased between 2 to 10 times but simultaneously the size and weight of the Swage Tool was decreased by about 50 percent. This accomplishment now becomes an outstanding engineering achievement. This achievement was only possible because of the computerized Patran, Nastran and Medusa programs.

  14. Particle Methods in Bluff Body Aerodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj

    . The implementation is two-dimensional and sequential. The implementation is validated against the analytic solution to the Perlman test case and by free-space simulations of the onset flow around fixed and rotating circular cylinders and bluff body flows around bridge sections. Finally a three-dimensional vortex...... is important. This dissertation focuses on the use of vortex particle methods and computational efficiency. The work is divided into three parts. A novel method for the simulation of the aerodynamic admittance in bluff body aerodynamics is presented. The method involves a model for describing oncoming...... section during the construction phase and the swimming motion of the medusa Aurelia aurita....

  15. The Mysteries and Curiosities of Mars: A Tour of Unusual and Unexplained Terrains

    Science.gov (United States)

    Kerber, L.

    2017-12-01

    The large amount of data available from orbiting satellites around Mars has provided a wealth of information about the Martian surface and geological history. The published literature tends to focus on regions of Mars for which there are ready explanations; however, many regions of Mars remain mysterious. In this contribution, we present some of the strangest and least explained terrains on Mars: The Taffy Terrain: This complex terrain, consisting of swirling layers with variably sized bands, is present mostly at the bottom of Hellas Basin, but versions of it can also be found on the floor of Melas Chasma and in the Medusae Fossae Formation near Apollinaris Sulci. While little has been written about the taffy terrain, hypotheses include "glacial features" and salt domes. The taffy terrain bears some resemblance to submarine salt domes in the Gulf of Mexico, glacial deposits with mixed ash and ice in Iceland, or chalk formations in Egypt's White Desert. The Fishscale Terrain: At the northern edge of Lucus Planum, the friable Medusae Fossae Formation transitions into a chaos-like terrain with hundreds of mesas forming a pattern like the scales of a fish. While chaos terrains are mysterious in general, this morphologically fresh, near-equatorial chaos is especially unusual. Polygonal Ridges in Gordii Dorsum: Also a part of the Medusae Fossae Formation, the ridges in Gordii Dorsum represent a negative image of the fishscale terrain—a intricate lattice of slender black ridges. These are thought to form via the embayment of the fishscale terrain with lava and the subsequent erosion of the original mesas. Horseshoe Features: These geomorphological features look like inverted barchan dunes, but they are actually pits eroded into the surface of the Medusae Fossae Formation. Channels surrounding Elysium Mons: These channel systems are among the most complex on Mars, but they appear on a young Amazonian lava surface. The channels cut through topography, anastomose, and

  16. Box jellyfish use terrestrial visual cues for navigation

    DEFF Research Database (Denmark)

    Garm, Anders; Oskarsson, Magnus; Nilsson, Dan-Eric

    2011-01-01

    been a puzzle why they need such a complex set of eyes. Here we report that medusae of the box jellyfish Tripedalia cystophora are capable of visually guided navigation in mangrove swamps using terrestrial structures seen through the water surface. They detect the mangrove canopy by an eye type...... that is specialized to peer up through the water surface and that is suspended such that it is constantly looking straight up, irrespective of the orientation of the jellyfish. The visual information is used to navigate to the preferred habitat at the edge of mangrove lagoons....

  17. Fields of dreams[Oil field development in the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    DeLuca, Marshall

    2001-04-01

    The steady increase in deepwater development projects in the US Gulf of Mexico is discussed, and individual field descriptions are given with details of the development, the water depth, onstream date, and location for the Typhoon (Chevron), Prince (El Paso), Brutus (Shell), Nansen/Boomvang (Kerr-McGee), Canyon Express (TotalFinaElf), Medusa (Murphy), Horn Mountain (BP), NaKika (Shell), Crazy Horse (BP), Serrano/Oregano (Shell), and Crosby (Shell) projects. Information on the production, reserves, water depths and locations of >100 projects in the area are tabulated.

  18. Molecular cloning of a preprohormone from sea anemones containing numerous copies of a metamorphosis-inducing neuropeptide: a likely role for dipeptidyl aminopeptidase in neuropeptide precursor processing

    DEFF Research Database (Denmark)

    Leviev, I; Grimmelikhuijzen, C J

    1995-01-01

    a polyp, a medusa, and a planula larva stage. Recently, a neuropeptide, metamorphosis in a hydroid planula larva to become a hydropolyp [Leitz, T., Morand, K. & Mann, M. (1994) Dev. Biol. 163, 440-446]. Here, we have cloned...... the precursor protein for this metamorphosis-inducing neuropeptide from sea anemones. The precursor protein is 514-amino acid residues long and contains 10 copies of the immature, authentic neuropeptide (Gln-Gln-Pro-Gly-Leu-Trp-Gly). All neuropeptide copies are preceded by Xaa-Pro or Xaa-Ala sequences...

  19. Reproductive and bloom patterns of Pelagia noctiluca in the Strait of Messina, Italy

    Science.gov (United States)

    Milisenda, G.; Martinez-Quintana, A.; Fuentes, V. L.; Bosch-Belmar, M.; Aglieri, G.; Boero, F.; Piraino, S.

    2018-02-01

    Investigations on sexual reproduction of jellyfish are essential to understanding mechanisms and patterns of outbreaks formation. Pelagia noctiluca (Forskål, 1775) (Scyphozoa) is known as the predominant jellyfish species with direct development in Western and Central Mediterranean Sea. In this paper we used integrated morphometric, histological, and biochemical approaches to investigate the annual reproductive biology of P. noctiluca from the Strait of Messina (South Thyrrenian Sea), a key proliferation area for this species due to favourable temperatures and high productivity. From November 2011 to September 2012, P. noctiluca sexual reproduction occurred throughout the year, with two seasonal peaks (autumn, spring) of spawning and embryonic development. Gonads of female P. noctiluca were characterized by a large amount of mature eggs of small size (diameter 200 μm) were detected during low availability of prey. Two morphometric indexes were applied: the Gonad-Somatic Index (GSI, gonadal/somatic tissue dry weight ratio) and Fecundity Index (FI, n° eggs mm-2 * gonadal dry weight). The FI showed longer spawning periods than the GSI, providing a better causal-mechanistic explanation for the year-round occurrence of P. noctiluca in the Strait of Messina. Protein contents of the gonads changed seasonally, with the highest concentrations during the pre-spawning periods. We suggest that investigations on jellyfish sexual reproduction can provide biological information relevant for understanding mechanisms of jellyfish blooms as well as for the management of coastal zones affected by outbreaks of gelatinous species.

  20. Direct evidence of an efficient energy transfer pathway from jellyfish carcasses to a commercially important deep-water species.

    Science.gov (United States)

    Dunlop, Kathy M; Jones, Daniel O B; Sweetman, Andrew K

    2017-12-12

    Here we provide empirical evidence of the presence of an energetic pathway between jellyfish and a commercially important invertebrate species. Evidence of scavenging on jellyfish carcasses by the Norway lobster (Nephrops norvegicus) was captured during two deployments of an underwater camera system to 250-287 m depth in Sognefjorden, western Norway. The camera system was baited with two Periphylla periphylla (Scyphozoa) carcasses to simulate the transport of jellyfish detritus to the seafloor, hereby known as jelly-falls. N. norveigus rapidly located and consumed a large proportion (>50%) of the bait. We estimate that the energy input from jelly-falls may represent a significant contribution to N. norvegicus energy demand (0.21 to 10.7 times the energy required for the population of N. norvegicus in Sognefjorden). This potentially high energetic contribution from jelly-falls highlights a possible role of gelatinous material in the support of commercial fisheries. Such an energetic pathway between jelly-falls and N. norvegicus could become more important with increases in jellyfish blooms in some regions.

  1. Sea Water Acidification Affects Osmotic Swelling, Regulatory Volume Decrease and Discharge in Nematocytes of the Jellyfish Pelagia noctiluca

    Directory of Open Access Journals (Sweden)

    Rossana Morabito

    2013-12-01

    Full Text Available Background: Increased acidification/PCO2 of sea water is a threat to the environment and affects the homeostasis of marine animals. In this study, the effect of sea water pH changes on the osmotic phase (OP, regulatory volume decrease (RVD and discharge of the jellyfish Pelagia noctiluca (Cnidaria, Scyphozoa nematocytes, collected from the Strait of Messina (Italy, was assessed. Methods: Isolated nematocytes, suspended in artificial sea water (ASW with pH 7.65, 6.5 and 4.5, were exposed to hyposmotic ASW of the same pH values and their osmotic response and RVD measured optically in a special flow through chamber. Nematocyte discharge was analyzed in situ in ASW at all three pH values. Results: At normal pH (7.65, nematocytes subjected to hyposmotic shock first expanded osmotically and then regulated their cell volume within 15 min. Exposure to hyposmotic ASW pH 6.5 and 4.5 compromised the OP and reduced or totally abrogated the ensuing RVD, respectively. Acidic pH also significantly reduced the nematocyte discharge response. Conclusion: Data indicate that the homeostasis and function of Cnidarians may be altered by environmental changes such as sea water acidification, thereby validating their use as novel bioindicators for the quality of the marine environment.

  2. Sea water acidification affects osmotic swelling, regulatory volume decrease and discharge in nematocytes of the jellyfish Pelagia noctiluca.

    Science.gov (United States)

    Morabito, Rossana; Marino, Angela; Lauf, Peter K; Adragna, Norma C; La Spada, Giuseppa

    2013-01-01

    Increased acidification/PCO2 of sea water is a threat to the environment and affects the homeostasis of marine animals. In this study, the effect of sea water pH changes on the osmotic phase (OP), regulatory volume decrease (RVD) and discharge of the jellyfish Pelagia noctiluca (Cnidaria, Scyphozoa) nematocytes, collected from the Strait of Messina (Italy), was assessed. Isolated nematocytes, suspended in artificial sea water (ASW) with pH 7.65, 6.5 and 4.5, were exposed to hyposmotic ASW of the same pH values and their osmotic response and RVD measured optically in a special flow through chamber. Nematocyte discharge was analyzed in situ in ASW at all three pH values. At normal pH (7.65), nematocytes subjected to hyposmotic shock first expanded osmotically and then regulated their cell volume within 15 min. Exposure to hyposmotic ASW pH 6.5 and 4.5 compromised the OP and reduced or totally abrogated the ensuing RVD, respectively. Acidic pH also significantly reduced the nematocyte discharge response. Data indicate that the homeostasis and function of Cnidarians may be altered by environmental changes such as sea water acidification, thereby validating their use as novel bioindicators for the quality of the marine environment. © 2014 S. Karger AG, Basel.

  3. Respiratory response to temperature of three populations of Aurelia aurita polyps in northern Europe.

    Directory of Open Access Journals (Sweden)

    Danja P Höhn

    Full Text Available The benthic life stage (polyp or scyphistoma of the bloom-forming jellyfish, Aurelia aurita (Linnaeus, 1759, also known as the moon jellyfish, contributes to the seasonal occurrence and abundance of medusa blooms via asexual reproduction. A. aurita is widely distributed in coastal areas in northern Europe, and one of the most studied jellyfish species. While the physiology of the visible medusa is largely understood, understanding of the physiology of the perennial benthic life-stage is scarce. To measure the physiological tolerance of A. aurita, the scyphistoma's temperature sensitivity across its distributional range was investigated. Respiration rates of polyps from three northern European locations exposed to 11 temperatures between 2 and 22°C were measured. There was a significant difference in respiration rate among the three polyp populations, which may reflect on differences in their thermal tolerance window. A critical temperature was reached at 14°C with the metabolic rate decreasing below and above that temperature. This pattern was less pronounced in the Norwegian population but polyps were able to survive, at least temporarily, those temperatures exceeding their natural range. While polyps collected from northern Norway, with a narrow environmental thermal window, displayed a low baseline metabolism with a Q10 value of 1.2, polyps from southern England and Scotland had Q10 values of 1.6 and 2.5, respectively. Differences in polyps' respiration rates across their distributional range suggest that populations have evolved adaptations to local environmental thermal conditions.

  4. Reproductive biology and variation of nuclear ribosomal ITS and ETS sequences in the Calligonum mongolicum complex (Polygonaceae

    Directory of Open Access Journals (Sweden)

    Wei Shi

    2017-01-01

    Full Text Available To explore the biosystematics of the Calligonum mongolicum complex (Polygonaceae, the flowering phenological period, breeding and pollination characters and seed set of the complex (C. Mongolicum Turze, C. chinense A. Los., C. gobicum A. Los., C. pumilum A. Los. and C. zaidamense A. Los. were documented in the Turpan Eremophyte Botanical Garden, China. The sequences of the nuclear ribosomal ITS and ETS region were employed to differentiate the C. mongolicum complex and other species in sect. Medusae. The results showed species of the C. mongolicum complex occupied overlapping flowering periods and had consistent pollination agents. Their breeding systems are all self-compatible, tend to be out-crossing and they interbreed amongst each other (out-crossing index, OCI = 4.The crosses within and amongst species had high seed sets (44 - 65%. Phylogenetic analyses of Calligonum sect. Medusae and the network analysis of nrDNA (ITS and ETS in the complex suggest interbreeding amongst “species” within the complex and provide evidence for taxonomically merging the five species in the complex. The detected hybridisation, occurring within the complex, suggests the need to improve traditional methods of ex situ plant conservation in botanical gardens for maintaining genetic diversity of Calligonum within and amongst species from different geographic areas.

  5. Diversity Dynamics in Nymphalidae Butterflies: Effect of Phylogenetic Uncertainty on Diversification Rate Shift Estimates

    Science.gov (United States)

    Peña, Carlos; Espeland, Marianne

    2015-01-01

    The species rich butterfly family Nymphalidae has been used to study evolutionary interactions between plants and insects. Theories of insect-hostplant dynamics predict accelerated diversification due to key innovations. In evolutionary biology, analysis of maximum credibility trees in the software MEDUSA (modelling evolutionary diversity using stepwise AIC) is a popular method for estimation of shifts in diversification rates. We investigated whether phylogenetic uncertainty can produce different results by extending the method across a random sample of trees from the posterior distribution of a Bayesian run. Using the MultiMEDUSA approach, we found that phylogenetic uncertainty greatly affects diversification rate estimates. Different trees produced diversification rates ranging from high values to almost zero for the same clade, and both significant rate increase and decrease in some clades. Only four out of 18 significant shifts found on the maximum clade credibility tree were consistent across most of the sampled trees. Among these, we found accelerated diversification for Ithomiini butterflies. We used the binary speciation and extinction model (BiSSE) and found that a hostplant shift to Solanaceae is correlated with increased net diversification rates in Ithomiini, congruent with the diffuse cospeciation hypothesis. Our results show that taking phylogenetic uncertainty into account when estimating net diversification rate shifts is of great importance, as very different results can be obtained when using the maximum clade credibility tree and other trees from the posterior distribution. PMID:25830910

  6. Green Fluorescence of Cytaeis Hydroids Living in Association with Nassarius Gastropods in the Red Sea

    KAUST Repository

    Prudkovsky, Andrey A.; Ivanenko, Viatcheslav N.; Nikitin, Mikhail A.; Lukyanov, Konstantin A.; Belousova, Anna; Reimer, James D.; Berumen, Michael L.

    2016-01-01

    Green Fluorescent Proteins (GFPs) have been reported from a wide diversity of medusae, but only a few observations of green fluorescence have been reported for hydroid colonies. In this study, we report on fluorescence displayed by hydroid polyps of the genus Cytaeis Eschscholtz, 1829 (Hydrozoa: Anthoathecata: Filifera) found at night time in the southern Red Sea (Saudi Arabia) living on shells of the gastropod Nassarius margaritifer (Dunker, 1847) (Neogastropoda: Buccinoidea: Nassariidae). We examined the fluorescence of these polyps and compare with previously reported data. Intensive green fluorescence with a spectral peak at 518 nm was detected in the hypostome of the Cytaeis polyps, unlike in previous reports that reported fluorescence either in the basal parts of polyps or in other locations on hydroid colonies. These results suggest that fluorescence may be widespread not only in medusae, but also in polyps, and also suggests that the patterns of fluorescence localization can vary in closely related species. The fluorescence of polyps may be potentially useful for field identification of cryptic species and study of geographical distributions of such hydroids and their hosts.

  7. Environmental factors influencing the spatio-temporal distribution of Carybdea marsupialis (Lineo, 1978, Cubozoa) in South-Western Mediterranean coasts.

    Science.gov (United States)

    Canepa, Antonio; Fuentes, Verónica; Bosch-Belmar, Mar; Acevedo, Melissa; Toledo-Guedes, Kilian; Ortiz, Antonio; Durá, Elia; Bordehore, César; Gili, Josep-Maria

    2017-01-01

    Jellyfish blooms cause important ecological and socio-economic problems. Among jellyfish, cubozoans are infamous for their painful, sometimes deadly, stings and are a major public concern in tropical to subtropical areas; however, there is little information about the possible causes of their outbreaks. After a bloom of the cubomedusa Carybdea marsupialis (Carybdeidae) along the coast of Denia (SW Mediterranean, Spain) in 2008 with negative consequences for local tourism, the necessity to understand the ecological restrictions on medusae abundance was evident. Here we use different models (GAM and zero-inflated models) to understand the environmental and human related factors influencing the abundance and distribution of C. marsupialis along the coast of Denia. Selected variables differed among medusae size classes, showing different environmental restriction associated to the developmental stages of the species. Variables implicated with dispersion (e.g. wind and current) affected mostly small and medium size classes. Sea surface temperature, salinity and proxies of primary production (chl a, phosphates, nitrates) were related to the abundances of small and large size classes, highlighting the roles of springtime salinity changes and increased primary production that may promote and maintain high densities of this species. The increased primary (and secondary) production due to anthropogenic impact is implicated as the factor enabling high numbers of C. marsupialis to thrive. Recommendations for monitoring blooms of this species along the study area and applicable to Mediterranean Sea include focus effort in coastal waters where productivity have been enriched by anthropogenic activities.

  8. Environmental factors influencing the spatio-temporal distribution of Carybdea marsupialis (Lineo, 1978, Cubozoa in South-Western Mediterranean coasts.

    Directory of Open Access Journals (Sweden)

    Antonio Canepa

    Full Text Available Jellyfish blooms cause important ecological and socio-economic problems. Among jellyfish, cubozoans are infamous for their painful, sometimes deadly, stings and are a major public concern in tropical to subtropical areas; however, there is little information about the possible causes of their outbreaks. After a bloom of the cubomedusa Carybdea marsupialis (Carybdeidae along the coast of Denia (SW Mediterranean, Spain in 2008 with negative consequences for local tourism, the necessity to understand the ecological restrictions on medusae abundance was evident. Here we use different models (GAM and zero-inflated models to understand the environmental and human related factors influencing the abundance and distribution of C. marsupialis along the coast of Denia. Selected variables differed among medusae size classes, showing different environmental restriction associated to the developmental stages of the species. Variables implicated with dispersion (e.g. wind and current affected mostly small and medium size classes. Sea surface temperature, salinity and proxies of primary production (chl a, phosphates, nitrates were related to the abundances of small and large size classes, highlighting the roles of springtime salinity changes and increased primary production that may promote and maintain high densities of this species. The increased primary (and secondary production due to anthropogenic impact is implicated as the factor enabling high numbers of C. marsupialis to thrive. Recommendations for monitoring blooms of this species along the study area and applicable to Mediterranean Sea include focus effort in coastal waters where productivity have been enriched by anthropogenic activities.

  9. Green Fluorescence of Cytaeis Hydroids Living in Association with Nassarius Gastropods in the Red Sea

    KAUST Repository

    Prudkovsky, Andrey A.

    2016-02-03

    Green Fluorescent Proteins (GFPs) have been reported from a wide diversity of medusae, but only a few observations of green fluorescence have been reported for hydroid colonies. In this study, we report on fluorescence displayed by hydroid polyps of the genus Cytaeis Eschscholtz, 1829 (Hydrozoa: Anthoathecata: Filifera) found at night time in the southern Red Sea (Saudi Arabia) living on shells of the gastropod Nassarius margaritifer (Dunker, 1847) (Neogastropoda: Buccinoidea: Nassariidae). We examined the fluorescence of these polyps and compare with previously reported data. Intensive green fluorescence with a spectral peak at 518 nm was detected in the hypostome of the Cytaeis polyps, unlike in previous reports that reported fluorescence either in the basal parts of polyps or in other locations on hydroid colonies. These results suggest that fluorescence may be widespread not only in medusae, but also in polyps, and also suggests that the patterns of fluorescence localization can vary in closely related species. The fluorescence of polyps may be potentially useful for field identification of cryptic species and study of geographical distributions of such hydroids and their hosts.

  10. Working principle of bio-inspired shape memory alloy composite actuators

    International Nuclear Information System (INIS)

    Smith, Colin; Villanueva, Alex; Joshi, Keyur; Tadesse, Yonas; Priya, Shashank

    2011-01-01

    Recently, bio-inspired shape memory alloy composite (BISMAC) actuators have been shown to mimic the deformation characteristics of natural jellyfish medusa. In this study, a constant cross-section BISMAC actuator was characterized in terms of bending deflection and force in conjunction with microscopy to understand its deformation mechanism. The actuator showed bending deflection of 111% with respect to the active length along with a blocking force of 0.061 N. The resulting energy density of the composite actuator was 4929 J m −3 at an input voltage and current level of 12 V and 0.7 A, respectively. For a dry-state actuator, this performance is extremely high and represents an optimum combination of force and deflection. Experiments reveal that BISMAC's performance is related to the moment induced from tip attachment of the shape memory alloy (SMA) rather than to friction within the composite structure. A physics-based model of BISMAC structure is presented which shows that the actuator is highly sensitive to the distance between the SMA wire and the incompressible component. While SMA has both stress and strain limitations, the limiting factor in BISMAC actuators is dependent on separation distance. The limiting factor in BISMAC's suitability for mimicking the performance of medusa was experimentally found to be related to the maximum 4% strain of the SMA and not its force generation. (fast track communication)

  11. Diversity dynamics in Nymphalidae butterflies: effect of phylogenetic uncertainty on diversification rate shift estimates.

    Directory of Open Access Journals (Sweden)

    Carlos Peña

    Full Text Available The species rich butterfly family Nymphalidae has been used to study evolutionary interactions between plants and insects. Theories of insect-hostplant dynamics predict accelerated diversification due to key innovations. In evolutionary biology, analysis of maximum credibility trees in the software MEDUSA (modelling evolutionary diversity using stepwise AIC is a popular method for estimation of shifts in diversification rates. We investigated whether phylogenetic uncertainty can produce different results by extending the method across a random sample of trees from the posterior distribution of a Bayesian run. Using the MultiMEDUSA approach, we found that phylogenetic uncertainty greatly affects diversification rate estimates. Different trees produced diversification rates ranging from high values to almost zero for the same clade, and both significant rate increase and decrease in some clades. Only four out of 18 significant shifts found on the maximum clade credibility tree were consistent across most of the sampled trees. Among these, we found accelerated diversification for Ithomiini butterflies. We used the binary speciation and extinction model (BiSSE and found that a hostplant shift to Solanaceae is correlated with increased net diversification rates in Ithomiini, congruent with the diffuse cospeciation hypothesis. Our results show that taking phylogenetic uncertainty into account when estimating net diversification rate shifts is of great importance, as very different results can be obtained when using the maximum clade credibility tree and other trees from the posterior distribution.

  12. Radon soil-gas concentration and exhalation from mine tailings dams in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ongori, J.; Lindsay, R. [University of the Western Cape, Department of Physics, Private Bag X17, Bellville 7535 (South Africa); Newman, R. [Stellenbosch University, Department of Physics, Private Bag X1 Matieland 7602 (South Africa); Maleka, P. [iThemba LABS, Department of Nuclear Physics, P. O. Box 722, Somerset West 7129 (South Africa)

    2014-07-01

    , temperature, moisture and atmospheric pressure influence radon exhalation. At Kloof mine dump radon exhalation was mapped using a novel technique by means of a MEDUSA (Multi-Element Detector for Underwater Sediment Activity) gamma-ray detection system. The MEDUSA detector uses a CsI(Na) crystal and was mounted on the front of a 4x4 vehicle, 0.6 m off the ground. With this setup the MEDUSA detector measures the average activity concentration in the top 30 cm when accessible parts are traversed. The spectra acquired by the MEDUSA system were analysed and the activity concentrations for {sup 238}U, {sup 40}K and {sup 232}Th, were extracted using the Full Spectrum Analysis approach. Radon exhalation from a particular location in the mine dump was obtained by comparing the ratios of the activity concentrations of the {sup 214}Bi obtained in the field using the MEDUSA gamma-ray detector system to the activity concentrations of the {sup 214}Bi obtained in the laboratory using the HPGe gamma-ray detector system. In this case it is assumed that the {sup 40}K and {sup 232}Th series activity concentrations are not or hardly affected by radon exhalation. The application of this new technique gave an average normalised radon flux of 0.12±0.02 Bq.m{sup -2}.s{sup -1} for the mine dump. Document available in abstract form only. (authors)

  13. Prevailing negative soil biota effect and no evidence for local adaptation in a widespread Eurasian grass.

    Directory of Open Access Journals (Sweden)

    Viktoria Wagner

    2011-03-01

    Full Text Available Soil biota effects are increasingly accepted as an important driver of the abundance and distribution of plants. While biogeographical studies on alien invasive plant species have indicated coevolution with soil biota in their native distribution range, it is unknown whether adaptation to soil biota varies among populations within the native distribution range. The question of local adaptation between plants and their soil biota has important implications for conservation of biodiversity and may justify the use of seed material from local provenances in restoration campaigns.We studied soil biota effects in ten populations of the steppe grass Stipa capillata from two distinct regions, Europe and Asia. We tested for local adaptation at two different scales, both within (ca. 10-80 km and between (ca. 3300 km regions, using a reciprocal inoculation experiment in the greenhouse for nine months. Generally, negative soil biota effects were consistent. However, we did not find evidence for local adaptation: both within and between regions, growth of plants in their 'home soil' was not significantly larger relative to that in soil from other, more distant, populations.Our study suggests that negative soil biota effects can prevail in different parts of a plant species' range. Absence of local adaptation points to the possibility of similar rhizosphere biota composition across populations and regions, sufficient gene flow to prevent coevolution, selection in favor of plasticity, or functional redundancy among different soil biota. From the point of view of plant--soil biota interactions, our findings indicate that the current practice of using seeds exclusively from local provenances in ecosystem restoration campaigns may not be justified.

  14. DNA Barcoding the Medusozoa using mtCOI

    Science.gov (United States)

    Ortman, Brian D.; Bucklin, Ann; Pagès, Francesc; Youngbluth, Marsh

    2010-12-01

    The Medusozoa are a clade within the Cnidaria comprising the classes Hydrozoa, Scyphozoa, and Cubozoa. Identification of medusozoan species is challenging, even for taxonomic experts, due to their fragile forms and complex, morphologically-distinct life history stages. In this study 231 sequences for a portion of the mitochondrial Cytochrome Oxidase I (mtCOI) gene were obtained from 95 species of Medusozoans including; 84 hydrozoans (61 siphonophores, eight anthomedusae, four leptomedusae, seven trachymedusae, and four narcomedusae), 10 scyphozoans (three coronatae, four semaeostomae, two rhizostomae, and one stauromedusae), and one cubozoan. This region of mtCOI has been used as a DNA barcode (i.e., a molecular character for species recognition and discrimination) for a diverse array of taxa, including some Cnidaria. Kimura 2-parameter (K2P) genetic distances between sequence variants within species ranged from 0 to 0.057 (mean 0.013). Within the 13 genera for which multiple species were available, K2P distance between congeneric species ranged from 0.056 to 0.381. A cluster diagram generated by Neighbor Joining (NJ) using K2P distances reliably clustered all barcodes of the same species with ≥99% bootstrap support, ensuring accurate identification of species. Intra- and inter-specific variation of the mtCOI gene for the Medusozoa are appropriate for this gene to be used as a DNA barcode for species-level identification, but not for phylogenetic analysis or taxonomic classification of unknown sequences at higher taxonomic levels. This study provides a set of molecular tools that can be used to address questions of speciation, biodiversity, life-history, and population boundaries in the Medusozoa.

  15. Genetic diversity of populations and clones of Rhopilema esculentum in China based on AFLP analysis

    Science.gov (United States)

    Qiao, Hongjin; Liu, Xiangquan; Zhang, Xijia; Jiang, Haibin; Wang, Jiying; Zhang, Limin

    2013-03-01

    Amplified fragment length polymorphisms (AFLP) markers were developed to assess the genetic variation of populations and clones of Rhopilema esculentum Kishinouye (Scyphozoa, Rhizostomatidae). One hundred and seventy-nine loci from 56 individuals of two hatchery populations and two wild populations were genotyped with five primer combinations. The polymorphic ratio, Shannon's diversity index and average heterozygosity were 70.3%, 0.346 and 0.228 for the white hatchery population, 74.3%, 0.313, and 0.201 for the red hatchery population, 79.3%, 0.349, and 0.224 for the Jiangsu wild population, and 74.9%, 0.328 and 0.210 for the Penglai wild population, respectively. Thus, all populations had a relatively high level of genetic diversity. A specific band was identified that could separate the white from the red hatchery population. There was 84.85% genetic differentiation within populations. Individual cluster analysis using unweighted pair-group method with arithmetic mean (UPGMA) suggested that hatchery populations and wild populations could be divided. For the hatchery populations, the white and red populations clustered separately; however, for the wild populations, Penglai and Jiangsu populations clustered together. The genetic diversity at the clone level was also determined. Our data suggest that there are relatively high genetic diversities within populations but low genetic differentiation between populations, which may be related to the long-term use of germplasm resources from Jiangsu Province for artificial seeding and releasing. These findings will benefit the artificial seeding and conservation of the germplasm resources.

  16. Fine-Scale Layering of Mars Polar Deposits and Signatures of Ice Content in Nonpolar Material From Multiband SHARAD Data Processing

    Science.gov (United States)

    Campbell, Bruce A.; Morgan, Gareth A.

    2018-02-01

    The variation of Shallow Radar (SHARAD) echo strength with frequency reveals material dielectric losses and polar layer properties. Loss tangents for Elysium and Amazonis Planitiae deposits are consistent with volcanic flows and sediments, while the Medusae Fossae Formation, lineated valley fill, and lobate debris aprons have low losses consistent with a major component of water ice. Mantling materials in Arcadia and Utopia Planitiae have higher losses, suggesting they are not dominated by ice over large fractions of their thickness. In Gemina Lingula, there are frequent deviations from a simple dependence of loss on depth. Within reflector packets, the brightest reflectors are often different among the frequency subbands, and there are cases of reflectors that occur in only the high- or low-frequency echoes. Many polar radar reflections must arise from multiple thin interfaces, or single deposits of appropriate thickness, that display resonant scattering behaviors. Reflector properties may be linked to climate-controlled polar dust deposition.

  17. Evaluation of computed tomography on diagnosis of portosystemic collaterals in portal hypertension

    International Nuclear Information System (INIS)

    Ohe, Takashi; Kuronuma, Yukio; Fujiwara, Hiromichi; Ibuki, Yoshikazu; Maehara, Misao; Sugaya, Hitoshi; Harada, Takashi; Iwasaki, Naoya; Hyodo, Haruo

    1987-01-01

    We analyzed the diagnostic capability of CT to demonstrate the eight types of portosystemic collaterals in patient with portal hypertension. A total of 62 patients with portal hypertension underwent both CT and conventional angiography. All of these eight types of collaterals, such as esophageal varices, paraesophageal varices, coronary and short gastric pathway, dilated vein in splenic hilus, splenorenal and splenoretroperitoneal pathway, paraumbilical pathway and small veins on liver surface, caput medusa, azygos system, were demonstrated on CT better than angiography, except coronary and short gastric pathyway. And we also made comparative study of CT with per-rectal portal scintigraphy in 9 patients who underwent both studies. In 7 of these 9 patients, portosystemic collaterals were recognized on scintigram less than CT. In conclusion, CT provides much qualified images than conventional angiography or per-rectal portal scintigraphy in evaluating portosystemic collaterals. (author)

  18. Evaluation of computed tomography on diagnosis of portosystemic collaterals in portal hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Ohe, T; Kuronuma, Y; Fujiwara, H; Ibuki, Y; Maehara, M; Sugaya, H; Harada, T; Iwasaki, N; Hyodo, H

    1987-04-01

    We analyzed the diagnostic capability of CT to demonstrate the eight types of portosystemic collaterals in patient with portal hypertension. A total of 62 patients with portal hypertension underwent both CT and conventional angiography. All of these eight types of collaterals, such as esophageal varices, paraesophageal varices, coronary and short gastric pathway, dilated vein in splenic hilus, splenorenal and splenoretroperitoneal pathway, paraumbilical pathway and small veins on liver surface, caput medusa, azygos system, were demonstrated on CT better than angiography, except coronary and short gastric pathyway. And we also made comparative study of CT with per-rectal portal scintigraphy in 9 patients who underwent both studies. In 7 of these 9 patients, portosystemic collaterals were recognized on scintigram less than CT. In conclusion, CT provides much qualified images than conventional angiography or per-rectal portal scintigraphy in evaluating portosystemic collaterals.

  19. A method for in situ estimation of prey selectivity and predation rate in large plankton, exemplified with the jellyfish Aurelia aurita (L.)

    DEFF Research Database (Denmark)

    Hansson, L.J.

    2006-01-01

    , predation rate can be calculated as increase in gut content over time. Clearance rates for different prey can be calculated from predation rates and prey concentrations in the water, allowing accurate estimates of prey selectivity. Thus, the problem of unknown feeding history and feeding environment, which...... of a specific individual plankton predator in situ.After prey has been evacuated from the gut of an individual predator, the predator is incubated in situ, and observed by SCUBA-divers who recapture the individual after a defined time. Given that this incubation time is shorter than prey digestion time...... among individual jellyfish and among the various oral arms and gastric pouches within individuals. Clearance rates varied strongly with prey type. The medusae selected large crustacean prey (cladocerans and copepods/copepodites) over echinoderm larvae and copepod nauplii. Prey distribution within...

  20. Usefulness of computed tomography (CT) in the diagnosis of portosystemic collaterals in liver cirrhosis

    International Nuclear Information System (INIS)

    Tsukune, Yoshihiko

    1984-01-01

    This study assesses the usefulness of computed tomography (CT) in the diagnosis of portosystemic collaterals in liver cirrhosis. Seventy-eight patients with liver cirrhosis underwent both CT and angiography. Comparison was made between CT and angiography on eleven types of collaterals, and many of them were demonstrated on CT scans better than angio. Especially, esophageal varices, paraesophageal varices, umbilical pathway and caput medusa were diagnostic on CT scans. Gastrorenal collaterals, splenorenal collaterals, retroperitoneal pathway are also well demonstrated. Dilatation of azygos systems and small veins in the liver surface are only observed on CT scans. However, coronary varices and short gastric varices are well diagnostic in angiography. But considering all types of collaterals, it was stressed that angiography can be eliminated by CT in evaluation of collaterals in liver cirrhosis. (author)

  1. Seawater for the cooling of decay power. Partial report 1

    International Nuclear Information System (INIS)

    Poern, K.; Agnedal, P.O.; Evans, S.; Sundblad, B.

    1980-11-01

    It is stated that there should be provisions made for to cool down the decay power of a reactor. The intake of coolant should be kept clean of hindrances. The variations of the obstacles in the coolant intake of the Ringhals power plant has been investigated during the period 1976-78 in order to find the correlation of simultaneous conditions of wind, water flow, water level and temperature in relation to the blocking up. If one considers the dredged matter as typical for a medusae season, the amount of the substance can be considered having lognormal distribution. An estimate of the probability of the substance to exceed a critical limit at a given coolant flow can be made.(G.B.)

  2. Reflectance Confocal Microscopy in Lentigo Maligna.

    Science.gov (United States)

    Gamo, R; Pampín, A; Floristán, U

    2016-12-01

    Lentigo maligna is the most common type of facial melanoma. Diagnosis is complicated, however, as it shares clinical and dermoscopic characteristics with other cutaneous lesions of the face. Reflectance confocal microscopy is an imaging technique that permits the visualization of characteristic features of lentigo maligna. These include a disrupted honeycomb pattern and pagetoid cells with a tendency to show folliculotropism. These cells typically have a dendritic morphology, although they may also appear as round cells measuring over 20μm with atypical nuclei. Poorly defined dermal papillae and atypical cells may be seen at the dermal-epidermal junction and can form bridges resembling mitochondrial structures. Other characteristic findings include junctional swelling with atypical cells located around the follicles, resembling caput medusae. Reflectance confocal microscopy is a very useful tool for diagnosing lentigo maligna. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Photosynthetic planulae and planktonic hydroids: contrasting strategies of propagule survival

    Directory of Open Access Journals (Sweden)

    Patrizia Pagliara

    2000-12-01

    Full Text Available Settlement delays can be important to prevent propagule waste when proper settling substrates are not immediately available. Under laboratory conditions, the planulae of Clytia viridicans underwent two alternative developmental patterns. Some settled on the bottom, forming a hydranth-gonotheca complex that produced up to four medusae and later either degenerated or gave rise to a hydroid colony. Other planulae settled right below the air-water interface, forming floating colonies that eventually fell to the bottom and settled. Halecium nanum released planulae with a rich population of symbiotic zooxanthellae that survived into a rearing jar for three months. After a long period of apparent quiescence (possibly fuelled by photosynthetic activities of zooxanthellae the planulae produced new colonies. Both photosynthetic planulae and settlement at the interface air-water allow a delay in the passage from a planktonic to a fully functional benthic life.

  4. [Research advances in the effects of environmental factors on the growth and development of Aurelia spp].

    Science.gov (United States)

    Wang, Jian-Yan; Yu, Zhi-Gang; Zhen, Yu; Mi, Tie-Zhu; Yao, Qing-Zhen; Wang, Guo-Shan

    2012-11-01

    Aurelia spp. is a cosmopolitan coastal species, and also, one dominant species of large jellyfish in the coastal waters of China. In recent years, Aurelia spp. bloom events occur frequently in the world, causing severe damage to marine ecosystems, coastal economy, and society development. Aurelia spp. has a complicated life history comprising a benthic asexually-reproducing polyp generation and a sexually-reproducing medusa generation, and various vegetative reproduction (budding, strobilation, and podocyst production) and sexual reproduction. Surrounding physical and biological factors affect each growth stage of Aurelia spp., especially the juvenile stage of planktonic-benthic life cycle, which has major effect on the population dynamics of Aurelia spp. This paper reviewed the research advances in the effects of environmental factors on Aurelia spp. at its different growth and development stages, and discussed some problems worthy of further study, aimed to provide useful reference for the research of the key factors controlling the jellyfish blooms in coastal waters of China.

  5. Analyzers Measure Greenhouse Gases, Airborne Pollutants

    Science.gov (United States)

    2012-01-01

    to fuel cellular functions. "We think this chemical process did not exist when life first formed on Earth," he says, "because it is based on oxygen being available, and there was little oxygen available on the early Earth." It is possible that there are anaerobic regions beneath the sea floor in which life forms like those early non-Krebs Cycle microbes may yet exist. To detect and potentially collect samples of life emerging from hydrothermal vents, Flynn and his colleagues created Medusa, a multi-sensor instrument designed for long-term observation of diked vents on the ocean floor. When the vents erupt, Medusa assesses indicators of life within the expelled water. If the results are positive, the observatory collects samples and detaches from the ocean floor, making the long journey to the surface for retrieval by scientists. One of the indicators Medusa measures is the ratio of carbon isotopes in the water, namely carbon-12 and carbon-13. Living organisms preferentially take up carbon-12, Flynn says, so examining the ratio of these isotopes can help to determine the source of carbon in an environment as either biological or non-biological. "On Mars, there is evidence of localized methane in the atmosphere, and that methane could come from biological sources or from geochemical ones," Flynn says. "Determining the background planetary carbon isotope ratios and then evaluating the specific carbon ratios in this methane would help to determine how it was formed." A long-duration observatory similar to Medusa could one day provide essential evidence for or against the presence of life on the Red Planet or beneath the ice-crusted oceans of Europa.

  6. El mundo del libro: septiembre de 1964

    Directory of Open Access Journals (Sweden)

    Agustín Rodríguez Garavito

    1964-09-01

    Full Text Available El documento presenta las reseñas de los siguientes títulos: Los pasos en la sombra -Por Helcías Martán Góngora -Poesía- Ediciones Medusa. Colombia. Diccionario Biográfico de Artistas delNuevo Reino de Granada - Edición: Instituto Colombiano de Cultura Hispánica. Bogotá. Artículos y Ensayos -Por José Joaquín Vargas Valdés -Introducción y Selección de Aníbal Vargas Barón -Universidad de Oregón. U.S.A. De lo celeste y tenebroso -Gabriel Uliosa -Poemas- Editorial Iqueima. San Andrés y Providencia -James J. Parsons. -Talleres Gráficos del Banco de la República -Bogotá-Colombia

  7. Diagrama de estabilidad termodinámico del sistema de flotación cobre/agua/amilxantato

    Directory of Open Access Journals (Sweden)

    Beatriz Ramírez-Serrano

    2015-05-01

    Full Text Available El propósito del trabajo fue obtener el diagrama de estabilidad termodinámico que caracteriza al sistema de flotación cobre/agua/amilxantato, como parte del fundamento teórico necesario para el análisis del proceso de flotación de iones cobre con el reactivo colector de flotación amilxantato de potasio. A partir del sistema de reacciones químicas fundamentales y con ayuda del sofware Medusa se obtuvo el diagrama Eh-pH en el cual se definen las zonas de estabilidad de las diferentes especies químicas y se establece que en el rango de pH de 4 a 13 coexisten las especies xantogenadas de cobre(I y (II cuya relación disminuye con el incremento del pH.

  8. La ficción entre trauma real e imaginario: “Shelter” de José Emilio Pacheco

    Directory of Open Access Journals (Sweden)

    Margherita Cannavacciuolo

    2013-07-01

    Full Text Available The study analyzes the short story “Shelter” (1964 by José Emilio Pacheco (México D.F., 1939, published in the volume La sangre de Medusa y otros cuentos marginales (1991. The apocalypse marks the narrative construction of a traumatic imaginary related with dichotomy between real and imaginary trauma. The protagonist’s fear of a Third World War produces a suspension of reality’s principle and the projection of his interiority, leading to a fracture into the story between the level of imagination and the real experience. The texts reflects the configuration of a discourse where trauma plays as the significant in the organization of subjectivity and fiction.

  9. Feasibility of an XUV FEL Oscillator Driven by a SCRF Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H.; Freund, H. P.; Reinsch, M.

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) facility is currently under construction at Fermi National Accelerator Laboratory. Using a1-ms-long macropulse composed of up to 3000 micropulses, and with beam energies projected from 45 to 800 MeV, the possibility for an extreme ultraviolet (XUV) free-electron laser oscillator (FELO) with the higher energy is evaluated. We have used both GINGER with an oscillator module and the MEDUSA/OPC code to assess FELO saturation prospects at 120 nm, 40 nm, and 13.4 nm. The results support saturation at all of these wavelengths which are also shorter than the demonstrated shortest wavelength record of 176 nm from a storage-ring-based FELO. This indicates linac-driven FELOs can be extended into this XUV wavelength regime previously only reached with single-pass FEL configurations.

  10. Glaciambulata neumayeri gen. et sp. nov., a new Antarctic trachymedusa (Cnidaria: Hydrozoa, with a revision of the family Ptychogastriidae

    Directory of Open Access Journals (Sweden)

    Horia R. Galea

    2016-12-01

    Full Text Available A new genus and species of sympagic trachymedusa, Glaciambulata neumayeri gen. et sp. nov., are described based on material from Antarctica. Its generic features are compared to those of its relatives, Ptychogastria Allman, 1878 and Tesserogastria Beyer, 1959, and a review of the family Ptychogastriidae Mayer, 1910, based on literature data, is provided. From this, it results that the poorly-known Pectis antarctica Haeckel, 1879, formerly assigned to Ptychogastria by a number of authors, displays all characters of the contemporary rhopalonematid genus Voragonema Naumov, 1971. It is additionally demonstrated that V. laciniata Bouillon et al., 2001 is coterminous with P. antarctica, a finding that clarifies, 137 years later, the morphology and the taxonomic status of Haeckel’s medusa. In accordance with the Principle of Priority, Pectis is recognized as the valid name of the genus, and Voragonema is assigned to its synonymy. Similarly so, the specific name introduced by Haeckel has priority over laciniata.

  11. Nationalsozialismus und Holocaust in der spanischen Gegenwartsliteratur: Fiktionalisierte ‚images malgré tout‘ bei Ricardo Menéndez Salmón

    Directory of Open Access Journals (Sweden)

    Marco Thomas Bosshard

    2015-12-01

    Full Text Available Der vorliegende Artikel untersucht die literarischen Repräsentationen von nationalsozialistischen Kriegsverbrechen in den Romanen La ofensa und Medusa des spanischen Schriftstellers Ricardo Menéndez Salmón. Ausgehend von einer Kontextualisierung der Romane im Gesamtschaffen des Autors werden intertextuelle Bezüge nicht nur zu anderen literarischen Texten, sondern auch zur Theorie herausgearbeitet. Gegenüber dem im Zusammenhang mit Holocaust-Darstellungen oft postulierten ‚Bilderverbot‘ realisiert Menéndez Salmón in Anlehnung an Didi-Huberman fiktionalisierte images malgré tout im Medium der Sprache, deren Funktion über die Darstellung von Nazi-Verbrechen hinausgeht und eine metamediale Reflexion über den Zusammenhang von Bild, Sprache und Schrecken anstößt.

  12. Are Hox genes ancestrally involved in axial patterning? Evidence from the hydrozoan Clytia hemisphaerica (Cnidaria.

    Directory of Open Access Journals (Sweden)

    Roxane Chiori

    Full Text Available BACKGROUND: The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a "Hox code" predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. This assumption was mainly based on the interpretation of Hox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis. METHODOLOGY/PRINCIPAL FINDINGS: Hox, ParaHox and Hox-related genes have been investigated here by phylogenetic analysis and in situ hybridisation in Clytia hemisphaerica, an hydrozoan species with medusa and polyp stages alternating in the life cycle. Our phylogenetic analyses do not support an origin of ParaHox and Hox genes by duplication of an ancestral ProtoHox cluster, and reveal a diversification of the cnidarian HOX9-14 genes into three groups called A, B, C. Among the 7 examined genes, only those belonging to the HOX9-14 and the CDX groups exhibit a restricted expression along the oral-aboral axis during development and in the planula larva, while the others are expressed in very specialised areas at the medusa stage. CONCLUSIONS/SIGNIFICANCE: Cross species comparison reveals a strong variability of gene expression along the oral-aboral axis and during the life cycle among cnidarian lineages. The most parsimonious interpretation is that the Hox code, collinearity and conservative role along the antero-posterior axis are bilaterian innovations.

  13. A safer, urea-based in situ hybridization method improves detection of gene expression in diverse animal species.

    Science.gov (United States)

    Sinigaglia, Chiara; Thiel, Daniel; Hejnol, Andreas; Houliston, Evelyn; Leclère, Lucas

    2018-02-01

    In situ hybridization is a widely employed technique allowing spatial visualization of gene expression in fixed specimens. It has greatly advanced our understanding of biological processes, including developmental regulation. In situ protocols are today routinely followed in numerous laboratories, and although details might change, they all include a hybridization step, where specific antisense RNA or DNA probes anneal to the target nucleic acid sequence. This step is generally carried out at high temperatures and in a denaturing solution, called hybridization buffer, commonly containing 50% (v/v) formamide - a hazardous chemical. When applied to the soft-bodied hydrozoan medusa Clytia hemisphaerica, we found that this traditional hybridization approach was not fully satisfactory, causing extensive deterioration of morphology and tissue texture which compromised our observation and interpretation of results. We thus tested alternative solutions for in situ detection of gene expression and, inspired by optimized protocols for Northern and Southern blot analysis, we substituted the 50% formamide with an equal volume of 8M urea solution in the hybridization buffer. Our new protocol not only yielded better morphologies and tissue consistency, but also notably improved the resolution of the signal, allowing more precise localization of gene expression and reducing aspecific staining associated with problematic areas. Given the improved results and reduced manipulation risks, we tested the urea protocol on other metazoans, two brachiopod species (Novocrania anomala and Terebratalia transversa) and the priapulid worm Priapulus caudatus, obtaining a similar reduction of aspecific probe binding. Overall, substitution of formamide by urea during in situ hybridization offers a safer alternative, potentially of widespread use in research, medical and teaching contexts. We encourage other workers to test this approach on their study organisms, and hope that they will also

  14. Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. in response to temperature change

    Science.gov (United States)

    Aljbour, Samir M.; Zimmer, Martin; Kunzmann, Andreas

    2017-10-01

    Pelagic jellyfish blooms are increasing worldwide as a potential response to climate-change. However, virtually nothing is known about physiological responses of jellyfish to e.g. sudden changes in water temperature due to extreme weather events. When confronted with a sudden decrease or increase in water temperature by 6 °C, medusae of Cassiopea sp. exhibited a strong response in locomotor activity (i.e., bell pulsation increased and decreased by ca. 37 and 46% in hot and cold acute (2 h) treatments, respectively) relative to control. Although medusae significantly gained in body mass (wet weight) upon chronic (2 weeks) heat treatment, their body size (e.g., bell diameter) did not change over this time interval. In contrast, chronic cold treatment resulted in both significant shrinking (reduced diameter) and mass loss. Measurements of mitochondrial electron transport system (ETS) activities and rate of respiratory oxygen uptake (MO2) are good estimates of energy consumption and the potential aerobic metabolic rates of an organism. While both acute treatments significantly increased ETS-activities, acclimation over two weeks resulted in a drop in activities to the control levels. Whereas acute heat treatment significantly increased MO2, chronic exposure resulted in significant MO2 decrease compared to control; however no changes in MO2 could be observed in both acute and chronic cold treatments. Overall these results suggest an enhanced growth in response to global warming, whereas low temperatures may set the limits for successful invasion of Cassiopea into colder water bodies. Our results provide a framework for understanding the physiological tolerance of Cassiopea under possible future climate changes.

  15. Arte, mito e historia en dos obras de Ricardo Menéndez Salmón

    Directory of Open Access Journals (Sweden)

    Giovanna Fiordaliso

    2015-07-01

    Full Text Available Abstract – The object of this study are two works written by Ricardo Menéndez Salmon (1971- , La luz es más antigua que el amor (2010 and Medusa (2012. These texts are very interesting because, as postmodern works, they result as a mixture of different genres (essay, novel, biography and because they are built with a combination of fiction and history, through the red line of the reflection on Art. Through the experience of several artists, imagined or real, Ricardo Menéndez Salmon proposes a reflection on History and Myth, on the role of literature and art, establishing a significant relationship between the present and the past, memory and oblivion, language and images. Resumen – Objeto de este estudio son dos obras del escritor Ricardo Menéndez Salmón (1971- , La luz es más antigua que el amor (2010 y Medusa (2012. Estos textos son muy interesantes porque se fundan en una mezcla de varios géneros (ensayo, novela, biografía y se caracterizan por una manera original de combinar ficción e historia, reflexionando sobre el papel del Arte. A través de la experiencia de varios artistas, unos imaginados, otros reales, Ricardo Menéndez Salmón nos propone una reflexión sobre la Historia, el Mito, el papel de la literatura y el arte, el establecimiento de una relación significativa entre el presente y el pasado, la memoria y el olvido, el lenguaje y las imágenes.

  16. Gene Expression Data from the Moon Jelly, Aurelia, Provide Insights into the Evolution of the Combinatorial Code Controlling Animal Sense Organ Development.

    Directory of Open Access Journals (Sweden)

    Nagayasu Nakanishi

    Full Text Available In Bilateria, Pax6, Six, Eya and Dach families of transcription factors underlie the development and evolution of morphologically and phyletically distinct eyes, including the compound eyes in Drosophila and the camera-type eyes in vertebrates, indicating that bilaterian eyes evolved under the strong influence of ancestral developmental gene regulation. However the conservation in eye developmental genetics deeper in the Eumetazoa, and the origin of the conserved gene regulatory apparatus controlling eye development remain unclear due to limited comparative developmental data from Cnidaria. Here we show in the eye-bearing scyphozoan cnidarian Aurelia that the ectodermal photosensory domain of the developing medusa sensory structure known as the rhopalium expresses sine oculis (so/six1/2 and eyes absent/eya, but not optix/six3/6 or pax (A&B. In addition, the so and eya co-expression domain encompasses the region of active cell proliferation, neurogenesis, and mechanoreceptor development in rhopalia. Consistent with the role of so and eya in rhopalial development, developmental transcriptome data across Aurelia life cycle stages show upregulation of so and eya, but not optix or pax (A&B, during medusa formation. Moreover, pax6 and dach are absent in the Aurelia genome, and thus are not required for eye development in Aurelia. Our data are consistent with so and eya, but not optix, pax or dach, having conserved functions in sensory structure specification across Eumetazoa. The lability of developmental components including Pax genes relative to so-eya is consistent with a model of sense organ development and evolution that involved the lineage specific modification of a combinatorial code that specifies animal sense organs.

  17. An experimental study of Aurelia aurita feeding behaviour: Inference of the potential predation impact on a temperate estuarine nursery area

    Science.gov (United States)

    Pereira, Rita; Teodósio, Maria Alexandra; Garrido, Susana

    2014-06-01

    Temperate estuaries are nursery areas for economically important fisheries resources. The common jellyfish Aurelia aurita is a resident species in many of these areas, where it can reach high abundances. This work aimed to determine the potential for predation of A. aurita on zooplanktonic organisms and early life stages of fishes, measuring feeding rates at concentrations that mimic those occurring for zooplankton, fish eggs and larvae in an estuarine nursery area. A set of experiments was aimed at determining the feeding selectivity of jellyfish when offered a mixture of fish eggs and larvae and wild plankton. Clearance rates varied markedly with prey availability and concentrations. When given mixtures of different prey types, jellyfish preferentially elected some taxa (copepods and fish eggs). Data obtained in the laboratory experiments were used to infer the potential impact of jellyfish predation upon zooplankton and ichthyoplankton in the Guadiana estuary (Southern Iberia). Repeated sampling of zooplankton, fish eggs and medusae was undertaken during the summer season of 2011. Abundance determinations were combined with experimentally estimated clearance rates of individual medusa to infer the potential jellyfish-induced mortality on prey in the area. In June and early August jellyfish-induced mortality rates were very high, and half-life times (t1/2) were consequently short for the zooplankton and ichthyoplankton. Although the potentially overestimation of our feeding rates typical of confined laboratory experiments, the results show high ingestion and clearance rates at high temperatures, typical from summer condition, and results also suggest that either by predation on early life stages of fish, or by competition for food resources, jellyfish may have a significant impact on estuarine communities and its nursery function.

  18. Jellyfish support high energy intake of leatherback sea turtles (Dermochelys coriacea: video evidence from animal-borne cameras.

    Directory of Open Access Journals (Sweden)

    Susan G Heaslip

    Full Text Available The endangered leatherback turtle is a large, highly migratory marine predator that inexplicably relies upon a diet of low-energy gelatinous zooplankton. The location of these prey may be predictable at large oceanographic scales, given that leatherback turtles perform long distance migrations (1000s of km from nesting beaches to high latitude foraging grounds. However, little is known about the profitability of this migration and foraging strategy. We used GPS location data and video from animal-borne cameras to examine how prey characteristics (i.e., prey size, prey type, prey encounter rate correlate with the daytime foraging behavior of leatherbacks (n = 19 in shelf waters off Cape Breton Island, NS, Canada, during August and September. Video was recorded continuously, averaged 1:53 h per turtle (range 0:08-3:38 h, and documented a total of 601 prey captures. Lion's mane jellyfish (Cyanea capillata was the dominant prey (83-100%, but moon jellyfish (Aurelia aurita were also consumed. Turtles approached and attacked most jellyfish within the camera's field of view and appeared to consume prey completely. There was no significant relationship between encounter rate and dive duration (p = 0.74, linear mixed-effects models. Handling time increased with prey size regardless of prey species (p = 0.0001. Estimates of energy intake averaged 66,018 kJ • d(-1 but were as high as 167,797 kJ • d(-1 corresponding to turtles consuming an average of 330 kg wet mass • d(-1 (up to 840 kg • d(-1 or approximately 261 (up to 664 jellyfish • d(-1. Assuming our turtles averaged 455 kg body mass, they consumed an average of 73% of their body mass • d(-1 equating to an average energy intake of 3-7 times their daily metabolic requirements, depending on estimates used. This study provides evidence that feeding tactics used by leatherbacks in Atlantic Canadian waters are highly profitable and our results are consistent with estimates of mass gain prior to

  19. Martin Chalfie y la proteína verde fluorescente Martin Chalfie y la proteína verde fluorescente

    Directory of Open Access Journals (Sweden)

    Zacarías Pereira Vega

    2012-12-01

    Full Text Available The history of the green fluorescent protein (GFP starts with Osamu Shimomura at the beginning of the 1960s, with his discovery from the extracts of the Aequorea victoria jellyfish. However, it is not until the beginning of the 1990s, that the neurobiologist Martin Chalfie, applying genetic engineering tech- niques, achieved for the first time the heterology expression of the GFP in prokaryotes (E. coli and eukaryotes (Caernohabditis elegans, from a clone of the jellyfish’s gen that codifies the GFP prepared by Douglas Prasher. Besides fluorescing in green, the results from this work also demonstrated that it does not require any other cofactor or enzyme of the jellyfish for its expression or for the own forming of a fluorophore. At the same time, Chalfie proposed that the GFP could be used for the marking of cells on living ani- mals or the tag of proteins. Based upon these results, many scientists started working on research related to the GFP; actually this protein is used on different fields such as biotechnol- ogy, development biology, environmental chemistry and medicine. In the case of the latter, it has helped to elucidate the cellular mechanisms from which diseases are made of. Science owes Roger Tsien, amongst other contributions, the creation of differ- ent mutations of the GFP.La historia de la proteína verde fluorescente (GFP se inicia con Osamu Shimomura a principios de la década de 1960, con su descubrimiento de esta proteína a partir de extractos de la medusa Aequorea victoria. Sin embargo, es a principios de la década de 1990 que el neurobiólogo Martin Chalfie, aplicando técnicas de ingeniería genética, logra por primera vez la expresión heteróloga de la GFP en procariotas (Escherichia coli y eucariotas (Caernohabditis elegans, a partir de un clon del gen de la medusa que codifica a la GFP, preparado por Douglas Prasher. Además de fluorescer en verde, los resultados de este trabajo también demostraron que no se

  20. The use of tropical bromeliads (Tillandsia spp. for monitoring atmospheric pollution in the town of Florence, Italy

    Directory of Open Access Journals (Sweden)

    Luigi Brighigna

    2002-06-01

    Full Text Available The results of an experiment with two species of epiphytic angiosperms (Tillandsia caput-medusae and T. bulbosa for monitoring polycyclic aromatic hydrocarbons (PAHs in the air of Florence, Italy, are presented. PAHs are compounds known to be dangerous because of their carcinogenic potential, and among cormophytes, tillands (monocotyledons equipped with peculiar, specialised, epidermal trichomes are considered promising for air pollution biomonitoring. PAHs data were obtained using GC/MS analysis of plant extracts. Analytical data indicated an increasing trend in time of PAHs bioaccumulation. This result was compared with instrumentally recorded parameters such as meteorological (rain and environmental ones (PM10, indicating that trichome-operated physical capture of aerial particles was prominent in PAHs bioaccumulation on tillands. SEM (scanning electron microscope observations confirmed the role of the trichomes. This work indicates that tillands are particularly useful, low-cost, biomonitoring organisms inside their area of distribution (all Latin American countries and southern USA where these plants are easily available, but also wherever the climate allows them to surviveSe presentan los resultados de un experimento con dos especies de angiospermas epífitas (Tillandsia caput-medusae y T. bulbosa para monitorear hidrocarbonos aromáticos policíclicos (PAHs en el aire de Florencia, Italia. Los PAHs son compuestos que se sabe son peligrosos por su potencial carcinogénico, y, entre las cormófitas, las tilandsias (monocotiledóneas equipadas con tricomas epidérmicos, especializados y peculiares son consideradas promisorias para el biomonitoreo de la contaminación del aire. Se obtuvieron datos de PAHs usando el análisis de GC/MS de extractos de plantas. Los datos analíticos indicaron una tendencia creciente de la bioacumulación de PAH’s en el tiempo. Este resultado se comparó con los parámetros registrados instrumentalmente como

  1. Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

    Directory of Open Access Journals (Sweden)

    A. Yool

    2013-09-01

    Full Text Available Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO2 emissions. A major sink for atmospheric CO2, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs 2.6 and 8.5 using an intermediate complexity global ecosystem model, MEDUSA-2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s in ocean productivity (−6.3%. This impact has knock-on consequences for the abundance of the low trophic level biogeochemical actors modelled by MEDUSA-2.0 (−5.8%, and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m, and in the volume of ocean suboxic zones (+12.5%. A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a~better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change – for instance, productivity declines −21% in the Atlantic and increases +59% in

  2. Population density shapes patterns of survival and reproduction in Eleutheria dichotoma (Hydrozoa: Anthoathecata).

    Science.gov (United States)

    Dańko, Aleksandra; Schaible, Ralf; Pijanowska, Joanna; Dańko, Maciej J

    2018-01-01

    Budding hydromedusae have high reproductive rates due to asexual reproduction and can occur in high population densities along the coasts, specifically in tidal pools. In laboratory experiments, we investigated the effects of population density on the survival and reproductive strategies of a single clone of Eleutheria dichotoma . We found that sexual reproduction occurs with the highest rate at medium population densities. Increased sexual reproduction was associated with lower budding (asexual reproduction) and survival probability. Sexual reproduction results in the production of motile larvae that can, in contrast to medusae, seek to escape unfavorable conditions by actively looking for better environments. The successful settlement of a larva results in starting the polyp stage, which is probably more resistant to environmental conditions. This is the first study that has examined the life-history strategies of the budding hydromedusa E. dichotoma by conducting a long-term experiment with a relatively large sample size that allowed for the examination of age-specific mortality and reproductive rates. We found that most sexual and asexual reproduction occurred at the beginning of life following a very rapid process of maturation. The parametric models fitted to the mortality data showed that population density was associated with an increase in the rate of aging, an increase in the level of late-life mortality plateau, and a decrease in the hidden heterogeneity in individual mortality rates. The effects of population density on life-history traits are discussed in the context of resource allocation and the r/K-strategies' continuum concept.

  3. Structural and Developmental Disparity in the Tentacles of the Moon Jellyfish Aurelia sp.1.

    Directory of Open Access Journals (Sweden)

    David A Gold

    Full Text Available Tentacles armed with stinging cells (cnidocytes are a defining trait of the cnidarians, a phylum that includes sea anemones, corals, jellyfish, and hydras. While cnidarian tentacles are generally characterized as structures evolved for feeding and defense, significant variation exists between the tentacles of different species, and within the same species across different life stages and/or body regions. Such diversity suggests cryptic distinctions exist in tentacle function. In this paper, we use confocal and transmission electron microscopy to contrast the structure and development of tentacles in the moon jellyfish, Aurelia species 1. We show that polyp oral tentacles and medusa marginal tentacles display markedly different cellular and muscular architecture, as well as distinct patterns of cellular proliferation during growth. Many structural differences between these tentacle types may reflect biomechanical solutions to different feeding strategies, although further work would be required for a precise mechanistic understanding. However, differences in cell proliferation dynamics suggests that the two tentacle forms lack a conserved mechanism of development, challenging the textbook-notion that cnidarian tentacles can be homologized into a conserved bauplan.

  4. The Flinders University inductively driven spherical Tokamak project

    International Nuclear Information System (INIS)

    McCarthy, L.

    1998-01-01

    Full text: The Flinders University inductive start up Spherical Tokamak (ST) program is designed with two major functions: first a target plasma for a definitive test of rotating magnetic field (RMF) current drive, and secondly as a target plasma to be used in development of diagnostics for the collaboration between Flinders University and the Australian National Fusion Facility. A third goal is to maintain an Australian link to the international ST community at a time when this ST approach to plasma fusion is entering a ''second generation'' phase of larger machines, following the demonstration of resilience to major disruptions on START and MEDUSA, and excellent confinement properties, and β. Modelling of the optimum operating regime consistent with power supplies available at Flinders University, and comparisons of plasmas prepared by RMF alone with ohmically heated plasmas such as START, are presented to support the need for the design of this OH hot confined target plasma approach to RMF current drive as an alternative to that of pure RMF current drive at higher powers being attempted elsewhere, should that approach not prove successful. Progress on the experiments, which now includes successful tests of the toroidal field system and the OH coil system, is reported. The RMF facility will not be available till late in 1998. The case is made for retaining the valuable equipment resources of the Flinders University plasma research group and negotiating for the transfer of these to the Australian National Fusion Facility at the completion of this project at the end of 1999

  5. Invertebrados Fósiles del Paleozoico de Sonora, México

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cuen Romero

    2016-12-01

    Full Text Available A través de los fósiles es posible conocer la vida en el pasado geológico. La vida se originó en el mar hace 3700 Ma, siendo formas muy sencillas atribuibles a algas e invertebrados como las medusas; las primeras formas complejas se originaron a inicios del Paleozoico hace 541 Ma. El Paleozoico se divide en seis periodos: Cámbrico, Ordovícico, Silúrico, Devónico, Carbonífero y Pérmico; los cuales se caracterizan por una gran biodiversidad y abundancia de invertebrados. En Sonora se conocen diversas localidades con fósiles marinos del Paleozoico, destacando la presencia de poríferos, celenterados, braquiópodos, briozoarios, moluscos, artrópodos y equinodermos. El Paleozoico termina hace 252 Ma con la mayor extinción conocida en la historia de la biosfera, culminando con el 95% de las especies marinas.

  6. Trends in the diversity, distribution and life history strategy of Arctic Hydrozoa (Cnidaria.

    Directory of Open Access Journals (Sweden)

    Marta Ronowicz

    Full Text Available This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic, encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence data of Hydrozoa in the Arctic were prepared on the basis of historical and present-day literature. The Arctic was divided into ecoregions. Species were grouped into distributional categories according to their worldwide occurrences. Each species was classified according to life history strategy. The similarity of species composition among regions was calculated with the Bray-Curtis index. Average and variation in taxonomic distinctness were used to measure diversity at the taxonomic level. A total of 268 species were recorded. Arctic-boreal species were the most common and dominated each studied region. Nineteen percent of species were restricted to the Arctic. There was a predominance of benthic species over holo- and meroplanktonic species. Arctic, Arctic-Boreal and Boreal species were mostly benthic, while widely distributed species more frequently possessed a pelagic stage. Our results support hypothesis that the presence of a pelagic stage (holo- or meroplanktonic was not necessary to successfully recolonize the Arctic. The predominance of benthic Hydrozoa suggests that the Arctic could have been colonised after the Last Glacial Maximum by hydroids rafting on floating substrata or recolonising from glacial refugia.

  7. Environmental control of phase transition and polyp survival of a massive-outbreaker jellyfish.

    Directory of Open Access Journals (Sweden)

    Laura Prieto

    Full Text Available A number of causes have been proposed to account for the occurrence of gelatinous zooplankton (both jellyfish and ctenophore blooms. Jellyfish species have a complex life history involving a benthic asexual phase (polyp and a pelagic sexual phase (medusa. Strong environmental control of jellyfish life cycles is suspected, but not fully understood. This study presents a comprehensive analysis on the physicochemical conditions that control the survival and phase transition of Cotylorhiza tuberculata; a scyphozoan that generates large outbreaks in the Mediterranean Sea. Laboratory experiments indicated that the influence of temperature on strobilation and polyp survival was the critical factor controlling the capacity of this species to proliferate. Early life stages were less sensitive to other factors such as salinity variations or the competitive advantage provided by zooxanthellae in a context of coastal eutrophication. Coherently with laboratory results, the presence/absence of outbreaks of this jellyfish in a particular year seems to be driven by temperature. This is the first time the environmental forcing of the mechanism driving the life cycle of a jellyfish has been disentangled via laboratory experimentation. Projecting this understanding to a field population under climatological variability results in a pattern coherent with in situ records.

  8. Extract from the Zooxanthellate Jellyfish Cotylorhiza tuberculata Modulates Gap Junction Intercellular Communication in Human Cell Cultures

    Directory of Open Access Journals (Sweden)

    Stefano Piraino

    2013-05-01

    Full Text Available On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778 has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7 and human epidermal keratinocytes (HEKa. The composition of the jellyfish extract included photosynthetic pigments, valuable ω-3 and ω-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed.

  9. Cross-standard user description in mobile, medical oriented virtual collaborative environments

    Science.gov (United States)

    Ganji, Rama Rao; Mitrea, Mihai; Joveski, Bojan; Chammem, Afef

    2015-03-01

    By combining four different open standards belonging to the ISO/IEC JTC1/SC29 WG11 (a.k.a. MPEG) and W3C, this paper advances an architecture for mobile, medical oriented virtual collaborative environments. The various users are represented according to MPEG-UD (MPEG User Description) while the security issues are dealt with by deploying the WebID principles. On the server side, irrespective of their elementary types (text, image, video, 3D, …), the medical data are aggregated into hierarchical, interactive multimedia scenes which are alternatively represented into MPEG-4 BiFS or HTML5 standards. This way, each type of content can be optimally encoded according to its particular constraints (semantic, medical practice, network conditions, etc.). The mobile device should ensure only the displaying of the content (inside an MPEG player or an HTML5 browser) and the capturing of the user interaction. The overall architecture is implemented and tested under the framework of the MEDUSA European project, in partnership with medical institutions. The testbed considers a server emulated by a PC and heterogeneous user devices (tablets, smartphones, laptops) running under iOS, Android and Windows operating systems. The connection between the users and the server is alternatively ensured by WiFi and 3G/4G networks.

  10. Molecular phylogeny of Atractus (Serpentes, Dipsadidae), with emphasis on Ecuadorian species and the description of three new taxa

    Science.gov (United States)

    Arteaga, Alejandro; Mebert, Konrad; Valencia, Jorge H.; Cisneros-Heredia, Diego F.; Peñafiel, Nicolás; Reyes-Puig, Carolina; Vieira-Fernandes, José L.; Guayasamin, Juan M.

    2017-01-01

    Abstract We present a molecular phylogeny of snake genus Atractus, with an improved taxon sampling that includes 30 of the 140 species currently recognized. The phylogenetic tree supports the existence of at least three new species in the Pacific lowlands and adjacent Andean slopes of the Ecuadorian Andes, which we describe here. A unique combination of molecular, meristic and color pattern characters support the validity of the new species. With the newly acquired data, we propose and define the Atractus iridescens species group, as well as redefine the Atractus roulei species group. The species Atractus iridescens is reported for the first time in Ecuador, whereas Atractus bocourti and Atractus medusa are removed from the herpetofauna of this country. We provide the first photographic vouchers of live specimens for Atractus multicinctus, Atractus paucidens and Atractus touzeti, along with photographs of 19 other Ecuadorian Atractus species. The current status of Atractus occidentalis and Atractus paucidens is maintained based on the discovery of new material referable to these species. With these changes, the species number reported in Ecuador increases to 27, a number that is likely to increase as material not examined in this work becomes available and included in systematic studies. PMID:28769604

  11. GAAP: Genome-organization-framework-Assisted Assembly Pipeline for prokaryotic genomes.

    Science.gov (United States)

    Yuan, Lina; Yu, Yang; Zhu, Yanmin; Li, Yulai; Li, Changqing; Li, Rujiao; Ma, Qin; Siu, Gilman Kit-Hang; Yu, Jun; Jiang, Taijiao; Xiao, Jingfa; Kang, Yu

    2017-01-25

    Next-generation sequencing (NGS) technologies have greatly promoted the genomic study of prokaryotes. However, highly fragmented assemblies due to short reads from NGS are still a limiting factor in gaining insights into the genome biology. Reference-assisted tools are promising in genome assembly, but tend to result in false assembly when the assigned reference has extensive rearrangements. Herein, we present GAAP, a genome assembly pipeline for scaffolding based on core-gene-defined Genome Organizational Framework (cGOF) described in our previous study. Instead of assigning references, we use the multiple-reference-derived cGOFs as indexes to assist in order and orientation of the scaffolds and build a skeleton structure, and then use read pairs to extend scaffolds, called local scaffolding, and distinguish between true and chimeric adjacencies in the scaffolds. In our performance tests using both empirical and simulated data of 15 genomes in six species with diverse genome size, complexity, and all three categories of cGOFs, GAAP outcompetes or achieves comparable results when compared to three other reference-assisted programs, AlignGraph, Ragout and MeDuSa. GAAP uses both cGOF and pair-end reads to create assemblies in genomic scale, and performs better than the currently available reference-assisted assembly tools as it recovers more assemblies and makes fewer false locations, especially for species with extensive rearranged genomes. Our method is a promising solution for reconstruction of genome sequence from short reads of NGS.

  12. Nested radiations and the pulse of angiosperm diversification: increased diversification rates often follow whole genome duplications.

    Science.gov (United States)

    Tank, David C; Eastman, Jonathan M; Pennell, Matthew W; Soltis, Pamela S; Soltis, Douglas E; Hinchliff, Cody E; Brown, Joseph W; Sessa, Emily B; Harmon, Luke J

    2015-07-01

    Our growing understanding of the plant tree of life provides a novel opportunity to uncover the major drivers of angiosperm diversity. Using a time-calibrated phylogeny, we characterized hot and cold spots of lineage diversification across the angiosperm tree of life by modeling evolutionary diversification using stepwise AIC (MEDUSA). We also tested the whole-genome duplication (WGD) radiation lag-time model, which postulates that increases in diversification tend to lag behind established WGD events. Diversification rates have been incredibly heterogeneous throughout the evolutionary history of angiosperms and reveal a pattern of 'nested radiations' - increases in net diversification nested within other radiations. This pattern in turn generates a negative relationship between clade age and diversity across both families and orders. We suggest that stochastically changing diversification rates across the phylogeny explain these patterns. Finally, we demonstrate significant statistical support for the WGD radiation lag-time model. Across angiosperms, nested shifts in diversification led to an overall increasing rate of net diversification and declining relative extinction rates through time. These diversification shifts are only rarely perfectly associated with WGD events, but commonly follow them after a lag period. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  13. Are diversification rates and chromosome evolution in the temperate grasses (Pooideae) associated with major environmental changes in the Oligocene-Miocene?

    Science.gov (United States)

    Pimentel, Manuel; Escudero, Marcial; Sahuquillo, Elvira; Minaya, Miguel Ángel; Catalán, Pilar

    2017-01-01

    The Pooideae are a highly diverse C3 grass subfamily that includes some of the most economically important crops, nested within the highly speciose core-pooid clade. Here, we build and explore the phylogeny of the Pooideae within a temporal framework, assessing its patterns of diversification and its chromosomal evolutionary changes in the light of past environmental transformations. We sequenced five plastid DNA loci, two coding ( ndhF , matk ) and three non-coding ( trnH-psbA , trnT-L and trnL-F ), in 163 Poaceae taxa, including representatives for all subfamilies of the grasses and all but four ingroup Pooideae tribes. Parsimony and Bayesian phylogenetic analyses were conducted and divergence times were inferred in BEAST using a relaxed molecular clock. Diversification rates were assessed using the MEDUSA approach, and chromosome evolution was analyzed using the chromEvol software. Diversification of the Pooideae started in the Late-Eocene and was especially intense during the Oligocene-Miocene. The background diversification rate increased significantly at the time of the origin of the Poodae + Triticodae clade. This shift in diversification occurred in a context of falling temperatures that potentially increased ecological opportunities for grasses adapted to open areas around the world. The base haploid chromosome number n  = 7 has remained stable throughout the phylogenetic history of the core pooids and we found no link between chromosome transitions and major diversification events in the Pooideae.

  14. X-ray microanalysis of elements present in the matrix of cnidarian nematocysts.

    Science.gov (United States)

    Tardent, P; Zierold, K; Klug, M; Weber, J

    1990-01-01

    The composition and concentration of elements, in particular those of metallic cations, present in the intracapsular matrix and the wall of nematocysts of various cnidarian species have been recorded by means of X-ray microanalysis performed on 100nm thick cryosections. The predominant cation detected in the nematocyst matrix of the hydrozoan Podocoryne carnea (medusa), the scyphozoan Aurelia aurita (scyphopolyp) and the anthozoan Calliactis parasitica (tentacles and acontia) is K(+). Mg(2+) prevails in tentacular cysts of Anthopleura elegantissima, Actinia equina and Anemonia viridis, whereas, the acrorhagial cysts of A. elegantissima and A. equina contain Ca(2+) instead of Mg(2+). The acrorhagial cysts of A. viridis contain Mg(2+) like those of the tentacles. In the tentacular nematocysts of Podocoryne carnea polyps (Hydrozoa) on the other hand ambiguous element contents were found indicating that the cysts of this species has no preference for a particular cation. The high values of sulfur recorded in the matrix and particularly the wall of all the cysts are reflecting the presence of numerous protein disulfide bonds within the structural components (wall, shaft, tubule) of the nematocysts.

  15. THE POTENTIAL OF γ-RAY SPECTROSCOPY FOR SOIL PROXIMAL SURVEY IN CLAYEY SOILS

    Directory of Open Access Journals (Sweden)

    Simone Priori

    2014-01-01

    Full Text Available Gamma-ray spectroscopy surveys the intensity and distribution of γ-rays emitted from radionuclides of soils and bedrocks. The most important radionuclides of soils and rocks are: 40K, 232Th, 238U and 137Cs, the latter due to Chernobyl burst or radioactive pollution. Distribution and quantity of these radionuclides into the soil is strictly linked to parent material mineralogy and soil cation exchange capacity. The aim of this work is to show the makings of γ-ray spectroscopy proximal survey within experimental fields with clayey soils in western Sicily.The γ-ray spectrometer used for the fieldwork was “The Mole”, made by “The Soil Company”, “Medusa system” and the University of Groningen, from The Netherlands. During the survey of eight experimental fields, 55 soil samples were collected for laboratory analysis of particle size distribution, calcium carbonate, organic carbon and total nitrogen content. The results of the work showed the statistical correlations between soil features and γ-ray data. 

  16. New Mediterranean Marine biodiversity records (June 2013

    Directory of Open Access Journals (Sweden)

    I. SIOKOU

    2013-04-01

    Full Text Available This paper concerns records of species that have extended their distribution in the Mediterranean Sea. The finding of the rare brackish angiosperm Althenia filiformis in the island of Cyprus is interesting since its insertion in the Red Data Book of the Flora of Cyprus is suggested. The following species enriched the flora or fauna lists of the relevant countries: the red alga Sebdenia dichotoma (Greece, the hydrachnid mite Pontarachna adriatica (Slovenia, and the thalassinid Gebiacantha talismani (Turkey. Several alien species were recorded in new Mediterranean localities. The record of the burrowing goby Trypauchen vagina in the North Levantine Sea (Turkish coast, suggests the start of spreading of this Lessepsian immigrant in the Mediterranean Sea. The findings of the following species indicate the extension of their occurrence in the Mediterranean Sea: the foraminifer Amphistegina lobifera (island of Zakynthos, Greece, the medusa Cassiopea andromeda (Syria, the copepod Centropages furcatus (Aegean Sea, the decapod shrimp Melicertus hathor (island of Kastellorizo, Greece, the crab Menoethius monoceros (Gulf of Tunis, the barnacles Balanus trigonus, Megabalanus tintinnabulum, Megabalanus coccopoma and the bivalves Chama asperella, Cucurbitula cymbium (Saronikos Gulf, Greece.

  17. First Description of Sulphur-Oxidizing Bacterial Symbiosis in a Cnidarian (Medusozoa Living in Sulphidic Shallow-Water Environments.

    Directory of Open Access Journals (Sweden)

    Sylvie Abouna

    Full Text Available Since the discovery of thioautotrophic bacterial symbiosis in the giant tubeworm Riftia pachyptila, there has been great impetus to investigate such partnerships in other invertebrates. In this study, we present the occurrence of a sulphur-oxidizing symbiosis in a metazoan belonging to the phylum Cnidaria in which this event has never been described previously.Scanning Electron Microscope (SEM, Transmission Electron Microscope (TEM observations and Energy-dispersive X-ray spectroscopy (EDXs analysis, were employed to unveil the presence of prokaryotes population bearing elemental sulphur granules, growing on the body surface of the metazoan. Phylogenetic assessments were also undertaken to identify this invertebrate and microorganisms in thiotrophic symbiosis. Our results showed the occurrence of a thiotrophic symbiosis in a cnidarian identified as Cladonema sp.This is the first report describing the occurrence of a sulphur-oxidizing symbiosis in a cnidarian. Furthermore, of the two adult morphologies, the polyp and medusa, this mutualistic association was found restricted to the polyp form of Cladonema sp.

  18. Mostri e meraviglie. Echi dall’ antico nelle opere di Sylvia Plath

    Directory of Open Access Journals (Sweden)

    Letizia Lanza

    2010-11-01

    Full Text Available Nell’universo visionario di Sylvia Plath numerose sono le immagini, le fantasie, gli spettri che infestano e, d’altro canto, alimentano la sua anima e la sua poesia. In non piccolo numero affiorano da un passato più o meno remoto, anche dal patrimonio della mitologia classica, e si innestano su mostri più recenti, vivi, dunque pericolosissimi. È questo il caso della Gorgone Medusa, presente nelle evidenze letterarie e artistiche dell’antichità greco–romana ed etrusca, che trova infausta personificazione nella figura (reale della madre–matrigna Aurelia – come dimostrano sia brani in poesia e in prosa sia, di più ancora, le vibranti pagine dei Diari. È dunque l’eterno, irrisolto conflitto con la figura materna a determinare fin dagli inizi, nella poeta americana, tutta una serie di pulsioni, inquietudini, desideri, rifiuti, incertezze, ansie, in un continuo, sofferto alternarsi di vittorie e sconfitte. Motivi e ossessioni che trovano ulteriori benché diversi echi nei brani sull’esperienza matrimoniale con Hughes, destinata a chiudersi tragicamente, per Sylvia, con la delusione dell’adulterio e il successivo suicidio all’età di 30 anni.

  19. [The worlds of gods in medicine].

    Science.gov (United States)

    Karenberg, A

    2017-09-01

    A number of designations for diseases, medicines and human body structures derive from classical mythology. To date, these eponyms have not been systematically investigated. This paper provides an overview of this fringe component of medical vocabulary, looks at the history of several terms and formulates hypotheses as to why such creative etymologies have come into being. In addition to relevant texts on ancient mythology, a variety of medical textbooks from the early modern period were analyzed. Between the 16th and the 20th centuries some 30 figures from Greek and Roman literature made their way into the terminology of medical sciences. A few of these expressions can be encountered in clinical use (e. g., Caput Medusae, Proteus, Oedipus complex) and remain official anatomical (atlas, Achilles tendon) or pharmaceutical nomenclature (atropine, morphine). The choice of these designations has often been similarity of form or analogies in function. Classical eponyms have gained acceptance on account of their succinctness, conciseness and scholarly veneer. Finally, this vocabulary shares its origin with other relevant terminology. In clinical classes, mythological designations can serve as a point of departure for digressions into literary, art and medical history in order to provide an understanding of cultural traditions and enhance education.

  20. [Sir Arthur Conan Doyle, Sherlock Holmes and infectious diseases].

    Science.gov (United States)

    Ledermann D, Walter

    2010-10-01

    Besides a pleasant author of best sellers, Sir Arthur Conan Doyle was a medical doctor, writing excellent short stories about the exercise of his profession in England. However, even he mentions The British Medical Journal and The Lancet in the Sherlock Holmes's stories, when in the plot introduces infectious diseases, Conan Doyle ignores important discoveries in the field of tetanus. Anyway, the appearing of infectious diseases in the adventures of the detective are rare: one mention of tetanus, another of leprosy and- the most analyzed in medical literature a case of murder by inoculation of bacteria, probably the agent of melioidosis. Also he makes his hero discovers the toxic actions of a medusa and a transplant of solid organ. Little for a physician and less for an author who also wrote science fiction: it seems that the history of the great medical discoveries at the end of nineteenth century and beginning of the twentieth has passed by his side.., and he just couldn't see it.

  1. The use of tropical bromeliads (Tillandsia spp.) for monitoring atmospheric pollution in the town of Florence, Italy.

    Science.gov (United States)

    Brighigna, Luigi; Papini, Alessio; Mosti, Stefano; Cornia, Andrea; Bocchini, Paola; Galletti, Guido

    2002-06-01

    The results of an experiment with two species of epiphytic angiosperms (Tillandsia caput-medusae and T. bulbosa) for monitoring polycyclic aromatic hydrocarbons (PAHs) in the air of Florence, Italy, are presented. PAHs are compounds known to be dangerous because of their carcinogenic potential, and among cormophytes, tillands (monocotyledons equipped with peculiar, specialised, epidermal trichomes) are considered promising for air pollution biomonitoring. PAHs data were obtained using GC/MS analysis of plant extracts. Analytical data indicated an increasing trend in time of PAHs bioaccumulation. This result was compared with instrumentally recorded parameters such as meteorological (rain) and environmental ones (PM10), indicating that trichome-operated physical capture of aerial particles was prominent in PAHs bioaccumulation on tillands. SEM (scanning electron microscope) observations confirmed the role of the trichomes. This work indicates that tillands are particularly useful, low-cost biomonitoring organisms inside their area of distribution (all Latin American countries and southern USA) where these plants are easily available, but also wherever the climate allows them to survive.

  2. Hunting in bioluminescent light: Vision in the nocturnal box jellyfish Copula sivickisi

    Directory of Open Access Journals (Sweden)

    Anders eGarm

    2016-03-01

    Full Text Available Cubomedusae all have a similar set of six eyes on each of their four rhopalia. Still, there is a great variation in activity patterns with some species being strictly day active while others are strictly night active. Here we have examined the visual ecology of the medusa of the night active Copula sivickisi from Okinawa using optics, morphology, electrophysiology, and behavioural experiments. We found the lenses of both the upper and the lower lens eyes to be image forming but under-focused, resulting in low spatial resolution in the order of 10 – 15 degrees. The photoreceptor physiology is similar in the two lens eyes and they have a single opsin peaking around 460 nm and low temporal resolution with a flicker fusion frequency (fff of 2.5 Hz indicating adaptions to vision in low light intensities. Further, the outer segments have fluid filled swellings, which may concentrate the light in the photoreceptor membrane by total internal reflections, and thus enhance the signal to noise ratio in the eyes. Finally our behavioural experiments confirmed that the animals use vision when hunting. When they are active at night they seek out high prey-concentration by visual attraction to areas with abundant bioluminescent flashes triggered by their prey.

  3. Resolution of fine biological structure including small narcomedusae across a front in the Southern California Bight

    Science.gov (United States)

    McClatchie, Sam; Cowen, Robert; Nieto, Karen; Greer, Adam; Luo, Jessica Y.; Guigand, Cedric; Demer, David; Griffith, David; Rudnick, Daniel

    2012-04-01

    We sampled a front detected by SST gradient, ocean color imagery, and a Spray glider south of San Nicolas Island in the Southern California Bight between 14 and 18 October 2010. We sampled the front with an unusually extensive array of instrumentation, including the Continuous Underway Fish Egg Sampler (CUFES), the undulating In Situ Ichthyoplankton Imaging System (ISIIS) (fitted with temperature, salinity, oxygen, and fluorescence sensors), multifrequency acoustics, a surface pelagic trawl, a bongo net, and a neuston net. We found higher fluorescence and greater cladoceran, decapod, and euphausiid densities in the front, indicating increased primary and secondary production. Mesopelagic fish were most abundant in oceanic waters to the west of the front, market squid were abundant in the front associated with higher krill and decapod densities, and jack mackerel were most common in the front and on the shoreward side of the front. Egg densities peaked to either side of the front, consistent with both offshore (for oceanic squid and mesopelagic fish) and shelf origins (for white croaker and California halibut). We discovered unusually high concentrations of predatory narcomedusae in the surface layer of the frontal zone. Potential ichthyoplankton predators were more abundant either in the front (decapods, euphausiids, and squid) or shoreward of the front (medusae, chaetognaths, and jack mackerel). For pelagic fish like sardine, which can thrive in less productive waters, the safest place to spawn would be offshore because there are fewer potential predators.

  4. Activated leukocyte cell adhesion molecule expression in oral squamus cell carcinoma and its association with clinical and histopathologic parameters

    Directory of Open Access Journals (Sweden)

    Omid Mirmohammadkhani

    2013-03-01

    Full Text Available Introduction: The aim of the present research was to study the expression of activated-leukocyte cell adhesion molecule (ALCAM in oral squamus cell carcinoma (OSCC and its association with histopathological and prognostic parameters.Materials and Methods: In a cross-sectional study, samples of OSCC tumors from tongue and oral mucosa available in Institute of Cancer of Imam Hospital in Tehran were simultaneously studied in term of tumor size, lymph node metastasis, and differentiation and ALCAM expression. Analysis was performed using multiple logistic regression models. Results: 39 samples of tongue and 19 samples of oral medusa belonged to 35 men and 23 women with mean (Standard deviation of age 58(15.69 years of old were studied. More than half of lesions had good differentiation and lymph node metastasis. From all, 42 (72.4% of samples were positive of ALCAM. Odds of ALCAM total expression in tumors with size of at least 20 mm was more (OR=3.9, p=0.001. Odds ratios for membranous and cytoplasmic expression of ALCAM in positive samples of lymph node metastasis (OR=0.4, p=0.03 and in patients with age 40 and more (OR=2.7, p=0.002 were respectively significant.Conclusion: The study confirmed positive relationship between ALCAM expression and tumor size as while as ambiguity of ALCAM role as a "Paradox" indicator. Next researches may make the role of ALCAM in different phases of tumor developing clearer

  5. High-power free-electron laser amplifier using a scalloped electron beam and a two-stage wiggler

    Directory of Open Access Journals (Sweden)

    D. C. Nguyen

    2006-05-01

    Full Text Available High-power free-electron laser (FEL amplifiers present many practical design and construction problems. One such problem is possible damage to any optical beam control elements beyond the wiggler. The ability to increase the optical beam’s divergence angle after the wiggler, thereby reducing the intensity on the first optical element, is important to minimize such damage. One proposal to accomplish this optical beam spreading is to pinch the electron beam thereby focusing the radiation as well. In this paper, we analyze an approach that relies on the natural betatron motion to pinch the electron beam near the end of the wiggler. We also consider a step-tapered, two-stage wiggler to enhance the efficiency. The combination of a pinched electron beam and step-taper wiggler leads to additional optical guiding of the optical beam. This novel configuration is studied in simulation using the MEDUSA code. For a representative set of beam and wiggler parameters, we discuss (i the effect of the scalloped beam on the interaction in the FEL and on the focusing and propagation of the radiation, and (ii the efficiency enhancement in the two-stage wiggler.

  6. Deep pelagic food web structure as revealed by in situ feeding observations.

    Science.gov (United States)

    Choy, C Anela; Haddock, Steven H D; Robison, Bruce H

    2017-12-06

    Food web linkages, or the feeding relationships between species inhabiting a shared ecosystem, are an ecological lens through which ecosystem structure and function can be assessed, and thus are fundamental to informing sustainable resource management. Empirical feeding datasets have traditionally been painstakingly generated from stomach content analysis, direct observations and from biochemical trophic markers (stable isotopes, fatty acids, molecular tools). Each approach carries inherent biases and limitations, as well as advantages. Here, using 27 years (1991-2016) of in situ feeding observations collected by remotely operated vehicles (ROVs), we quantitatively characterize the deep pelagic food web of central California within the California Current, complementing existing studies of diet and trophic interactions with a unique perspective. Seven hundred and forty-three independent feeding events were observed with ROVs from near-surface waters down to depths approaching 4000 m, involving an assemblage of 84 different predators and 82 different prey types, for a total of 242 unique feeding relationships. The greatest diversity of prey was consumed by narcomedusae, followed by physonect siphonophores, ctenophores and cephalopods. We highlight key interactions within the poorly understood 'jelly web', showing the importance of medusae, ctenophores and siphonophores as key predators, whose ecological significance is comparable to large fish and squid species within the central California deep pelagic food web. Gelatinous predators are often thought to comprise relatively inefficient trophic pathways within marine communities, but we build upon previous findings to document their substantial and integral roles in deep pelagic food webs. © 2017 The Authors.

  7. Measurements of Prompt Radiation-Induced Conductivity of Pyralux®

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, E. Frederick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Radiation Effects Experimentation Dept.; Zarick, Thomas Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Radiation Effects Experimentation Dept.; McLain, Michael Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Radiation Effects Experimentation Dept.; Sheridan, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Radiation Effects Experimentation Dept.; Preston, Eric F. [ITT Exelis, Colorado Springs, CO (United States); Stringer, Thomas Arthur [ITT Exelis, Colorado Springs, CO (United States)

    2014-01-01

    In this report, measurements of the prompt radiation-induced conductivity (RIC) in 3 mil samples of Pyralux® are presented as a function of dose rate, pulse width, and applied bias. The experiments were conducted with the Medusa linear accelerator (LINAC) located at the Little Mountain Test Facility (LMTF) near Ogden, UT. The nominal electron energy for the LINAC is 20 MeV. Prompt conduction current data were obtained for dose rates ranging from ~2 x 109 rad(Si)/s to ~1.1 x 1011 rad(Si)/s and for nominal pulse widths of 50 ns and 500 ns. At a given dose rate, the applied bias across the samples was stepped between -1500 V and 1500 V. Calculated values of the prompt RIC varied between 1.39x10-8 Ω-1 · m-1 and 2.67x10-7 Ω-1 · m-1 and the prompt RIC coefficient varied between 1.25x10-18 Ω-1 · m-1/(rad/s) and 1.93x10-17 Ω-1 · m-1/(rad/s).

  8. A novel modelling framework to prioritize estimation of non-point source pollution parameters for quantifying pollutant origin and discharge in urban catchments.

    Science.gov (United States)

    Fraga, I; Charters, F J; O'Sullivan, A D; Cochrane, T A

    2016-02-01

    Stormwater runoff in urban catchments contains heavy metals (zinc, copper, lead) and suspended solids (TSS) which can substantially degrade urban waterways. To identify these pollutant sources and quantify their loads the MEDUSA (Modelled Estimates of Discharges for Urban Stormwater Assessments) modelling framework was developed. The model quantifies pollutant build-up and wash-off from individual impervious roof, road and car park surfaces for individual rain events, incorporating differences in pollutant dynamics between surface types and rainfall characteristics. This requires delineating all impervious surfaces and their material types, the drainage network, rainfall characteristics and coefficients for the pollutant dynamics equations. An example application of the model to a small urban catchment demonstrates how the model can be used to identify the magnitude of pollutant loads, their spatial origin and the response of the catchment to changes in specific rainfall characteristics. A sensitivity analysis then identifies the key parameters influencing each pollutant load within the stormwater given the catchment characteristics, which allows development of a targeted calibration process that will enhance the certainty of the model outputs, while minimizing the data collection required for effective calibration. A detailed explanation of the modelling framework and pre-calibration sensitivity analysis is presented. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. First Description of Sulphur-Oxidizing Bacterial Symbiosis in a Cnidarian (Medusozoa) Living in Sulphidic Shallow-Water Environments.

    Science.gov (United States)

    Abouna, Sylvie; Gonzalez-Rizzo, Silvina; Grimonprez, Adrien; Gros, Olivier

    2015-01-01

    Since the discovery of thioautotrophic bacterial symbiosis in the giant tubeworm Riftia pachyptila, there has been great impetus to investigate such partnerships in other invertebrates. In this study, we present the occurrence of a sulphur-oxidizing symbiosis in a metazoan belonging to the phylum Cnidaria in which this event has never been described previously. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) observations and Energy-dispersive X-ray spectroscopy (EDXs) analysis, were employed to unveil the presence of prokaryotes population bearing elemental sulphur granules, growing on the body surface of the metazoan. Phylogenetic assessments were also undertaken to identify this invertebrate and microorganisms in thiotrophic symbiosis. Our results showed the occurrence of a thiotrophic symbiosis in a cnidarian identified as Cladonema sp. This is the first report describing the occurrence of a sulphur-oxidizing symbiosis in a cnidarian. Furthermore, of the two adult morphologies, the polyp and medusa, this mutualistic association was found restricted to the polyp form of Cladonema sp.

  10. Iirimaale : [luuletused] / Percy Bysshe Shelley ; tlk. Minni Nurme, Ants, Oras

    Index Scriptorium Estoniae

    Shelley, Percy Bysshe

    2006-01-01

    Sisu: Iirimaale ; Armastuse roos ; Harrietile ; Muutlikkus ; Vangist vabanenud sõbrale ; Minevik ; Byronile ; Kaduvik ; Laul : "Maa magas, külm kui surm..." ; Hümn vaimsele ilule ; Laul : "Too aeg on läind, mu armsam, läind..." ; Ozymandias ; Sonett ; India serenaad ; Leonardo da Vinci Medusa Firenze kunstikogus ; Armu filosoofia ; Ood läänetuulele ; Mary Shelleyle ; Laul briti meestele ; Uus rahvushümn ; Inglismaa 1819. a. ; Ära madu ärata ; Head ööd! ; Pilv ; Apolloni hümn ; Paani hümn ; Lõoke ; Vabadus ; Suvi ja talv ; Maailmarändurid ; Küsimus ; Aeg, mis hajus ; Ööle ; -le : "Üht sõna on labastand suud..." ; -le : "Kui kirg kord mööduks, aga jääks..." ; Õhtu Ponte al Marel, Pisas ; Mälestus ; Muusika ; Aeg ; Põgenejad ; Ma olla kuningas ei tahaks ; "Homne päev, kus oled praegu..." ; "Laps rahus kord on emaihus..." ; Üksik lind ; "Kui lamp pihuks langend..." ; Epitaaf ; Kutse Janeþile ; Tähed vilkusid valgust ; Leinalaul ; Pühendus. Eluloolisi andmeid autori kohta lk. 389

  11. Modelling the dynamics of total precipitation and aboveground net primary production of fescue-feather grass steppe at Askania Nova according to global climate change scenariosModelling the dynamics of total precipitation and aboveground net primary production of fescue-feather grass steppe at Askania Nova according to global climate change scenarios

    Directory of Open Access Journals (Sweden)

    S. O. Belyakov

    2017-01-01

    Full Text Available This article discusses modelling of Aboveground Net Primary Production (ANPP of steppe (arid grassland ecosystems plant species in relation to changes in total precipitation over the previous year at the “Stara” study site, Biosphere Reserve “Askania-Nova”, Khersonregion (Ukraine. To investigate linkages between precipitation and Aboveground Net Primary Production, correlation analysis was chosen and a time series regression analysis was based on the data set for the period 1988–2012. The NPP dependence on quantity of precipitation was found to be more significant for the previous autumn-winter-spring period (AWSP than for the previous 12 month period. A regression model of ANPP’s dependence on AWSP is proposed. This model was further validated by the authors’ samples of ANPP, collected at the “Stara” study site in 2013–2016. The regression model showed a non-linear (quadratic dependence of net primary production of zonal and intrazonal plant coenoses and total precipitation for the autumn-winter-spring period for arid grasslands with a coefficient of determination equal to 0.54 and significance level less than 0.05. The non-linear equation for these relations, visualized by a parabola curve, was calculated using the Nonlinear Least-Squares Regression Method. The data set, based on calculated predicted values, using the calculated equation, had a similar dynamic to the historical data on ANPP, but the model could not predict critical values. For this reason, additional studies are required for critical precipitation events. Non-linear response, investigated according to regression analysis, reveals optimal zones of plant growth, depending on the total precipitation level before the vegetation peak. For research areas where the dominant species are the turf grasses Stipa ucrainica P. Smirn., S. capillata L., S. lessingiana Trin. & Rupr., Festuca valesiaca Gaudin, Koeleria cristata (L. Pers. the optimal precipitation rates

  12. Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae)

    Science.gov (United States)

    Sendall, Kelly; Salazar-Vallejo, Sergio I.

    2013-01-01

    Caullery, 1944 from abyssal depths around Indonesia, Sternaspis scutata (Ranzani, 1817) from the Mediterranean Sea, Sternaspis spinosa Sluiter, 1882 from Indonesia, and Sternaspis thorsoni sp. n. from the Iranian Gulf. Two genera are newly proposed to incorporate the remaining species: Caulleryaspis and Petersenaspis. Caulleryaspis gen. n. is defined by the presence of falcate introvert hooks, seven abdominal segments, and soft shields with sediment particles firmly adhered on them; it includes two species: Caulleryaspis gudmundssoni sp. n. from Iceland and Caulleryaspis laevis (Caullery, 1944) comb. n. from Indonesia. Petersenaspis gen. n. is defined by the presence of spatulate introvert hooks, eight abdominal segments, and stiff shields with poorly defined ribs but no concentric line; it includes Petersenaspis capillata (Nonato, 1966) from Brazil and Petersenaspis palpallatoci sp. n. from the Philippines. Neotypes are proposed for eight species: Sternaspis thalassemoides, Sternaspis affinis, Sternaspis africana, Sternaspis costata, Sternaspis fossor, Sternaspis maior, Sternaspis scutata and Sternaspis spinosa, to stabilize these species-group names, and a lectotype is designated for Sternaspis laevis which is transferred to Caulleryaspis gen. n. The geographic range of most species appears to be much smaller than previously indicated, and for some species additional material in good condition is needed to clarify their distributions. Keys to genera and to all species are also included. PMID:23794844

  13. Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae

    Directory of Open Access Journals (Sweden)

    Kelly Sendall

    2013-04-01

    . spinosa Sluiter, 1882 from Indonesia, and S. thorsoni sp. n. from the Iranian Gulf. Two genera are newly proposed to incorporate the remaining species: Caulleryaspis and Petersenaspis. Caulleryaspis gen. n. is defined by the presence of falcate introvert hooks, seven abdominal segments, and soft shields with sediment particles firmly adhered on them; it includes two species: C. gudmundssoni sp. n. from Iceland and C. laevis (Caullery, 1944 comb. n. from Indonesia. Petersenaspis gen. n. is defined by the presence of spatulate introvert hooks, eight abdominal segments, and stiff shields with poorly defined ribs but no concentric line; it includes P. capillata (Nonato, 1966 from Brazil and P. palpallatoci sp. n. from the Philippines. Neotypes are proposed for eight species: S. thalassemoides, S. affinis, S. africana, S. costata, S. fossor, S. maior, S. scutata and S. spinosa, to stabilize these species-group names, and a lectotype is designated for S. laevis which is transferred to Caulleryaspis gen. n. The geographic range of most species appears to be much smaller than previously indicated, and for some species additional material in good condition is needed to clarify their distributions. Keys to genera and to all species are also included.

  14. Revision of sternaspis otto, 1821 (polychaeta, sternaspidae).

    Science.gov (United States)

    Sendall, Kelly; Salazar-Vallejo, Sergio I

    2013-01-01

    , 1944 from abyssal depths around Indonesia, Sternaspis scutata (Ranzani, 1817) from the Mediterranean Sea, Sternaspis spinosa Sluiter, 1882 from Indonesia, and Sternaspis thorsoni sp. n. from the Iranian Gulf. Two genera are newly proposed to incorporate the remaining species: Caulleryaspis and Petersenaspis. Caulleryaspis gen. n. is defined by the presence of falcate introvert hooks, seven abdominal segments, and soft shields with sediment particles firmly adhered on them; it includes two species: Caulleryaspis gudmundssoni sp. n. from Iceland and Caulleryaspis laevis (Caullery, 1944) comb. n. from Indonesia. Petersenaspis gen. n. is defined by the presence of spatulate introvert hooks, eight abdominal segments, and stiff shields with poorly defined ribs but no concentric line; it includes Petersenaspis capillata (Nonato, 1966) from Brazil and Petersenaspis palpallatoci sp. n. from the Philippines. Neotypes are proposed for eight species: Sternaspis thalassemoides, Sternaspis affinis, Sternaspis africana, Sternaspis costata, Sternaspis fossor, Sternaspis maior, Sternaspis scutata and Sternaspis spinosa, to stabilize these species-group names, and a lectotype is designated for Sternaspis laevis which is transferred to Caulleryaspis gen. n. The geographic range of most species appears to be much smaller than previously indicated, and for some species additional material in good condition is needed to clarify their distributions. Keys to genera and to all species are also included.

  15. Composition, abundance and distribution of macrozooplankton in Culebra Bay, Gulf of Papagayo, Pacific coast of Costa Rica and its value as bioindicator of pollution

    Directory of Open Access Journals (Sweden)

    Melinda Bednarski

    2004-12-01

    Full Text Available The abundance, distribution and composition of the macrozooplankton of Culebra Bay, Costa Rica (10º 38’ N - 85º 40’ W were studied at four stations throughout the dry (February - May and rainy (September - November seasons of 2000. The samples were collected at two-week intervals using a 500µm mesh net with a 0.5 m diameter opening. Copepods (23-31% and ostracods (20-34% were predominant throughout the year, followed by cladocerans (2.5-14%, zoea (6.6-9.5%, and siphonophores (2.5-7.2%. High densities of zooplankton were obtained in February and March with peak abundance on March 18. The lowest densities were observed on September 3 and November 5. Significant differences in abundances at each station were observed for the groups Acartia tonsa (Copepoda, Ctenophora, Medusae, Ostracoda, Zoea, and Amphipoda. Comparison of the dry and rainy seasons revealed significantly higher zooplankton abundance in the dry season and copepod domination of all stations; during the rainy season ostracods dominated the off-shore areas. Zooplankton abundance and distribution are influenced by upwelling, which occurs during the dry season in Culebra BayLa abundancia, distribución y composición del macrozooplancton fue estudiada en bahía Culebra Costa Rica (10º 38’ N and 85º 40’ W en cuatro estaciones durante la época seca (Febrero-Mayo y lluviosa (Setiembre - Noviembre del año 2000. Las muestras fueron colectadas en intervalos de dos semanas usando una red de 500µm de poro y 0.50-m de diámetro. Copépodos (23-31% y ostrácodos (20-34% fueron predominantes através del año, seguidos por los cladóceros (2.5-14%, zoea (6.6-9.5%, y sifonóforos (2.5-7.2%. Altas densidades de zooplancton fueron obtenidas en Febrero y Marzo, con un pico el 18 de Marzo. Las más bajas densidades fueron observadas el 3 de Septiembre y 5 de Noviembre. Se observaron diferencias significativas en las abundancias en cada estación para los copépodos de la especie Acartia

  16. The effects of inspiratory muscle strengthening on MIP and quality of life of elderly nursing home patients. (Los efectos del beneficio de la fuerza del músculo inspiratorio en la PIM y la calidad de la vida de los pacientes mayores de la clínica de reposo.

    Directory of Open Access Journals (Sweden)

    Silvia Correa Bacelar

    2008-01-01

    Full Text Available AbstractThe objective of this study was to compare the effects of inspiratory muscle strengthening on maximal inspiratory pressure (MIP and on quality of life among elderly nursing home patients. The study population was divided in two groups: experimental group- EG (n=21, 76.48 2.12 years and control group- CG (n=13, 75.69 2.26 years. The World Health Organization Quality of Life Group (WHOQOL-100 questionnaire was used to evaluate the quality of life of the subjects. A Manovacuometer (analogical, with an operational interval of –150 to +150 cmH2O; Critical Med/USA-2002 was used to evaluate MIP. The study protocol consisted of a gradual increase in workload (50%-100%; the sessions lasted 20 minutes and were composed of 7 series of strengthening (2 minutes each with a 1-minute interval between the series, 3 times a week for 10 weeks. Variance analysis of multivariate repeated measurements demonstrated significant differences only for MIP between CG (32,69±17,03 cmH2O versus 23,08±10,71 cmH2O and EG (31,67±11,11 cmH2O versus 55,24±23,26 cmH2O, and the latter was higher than the former (p= 0,00000. Therefore, we concluded that inspiratory muscle strengthening led to an increase in MIP that did not improve quality of life. However, further studies should be done in this population to validate a quality of life questionnaire specific for the elderly.ResumenEl objetivo de este estudio era comparar los efectos del músculo inspiratorio que consolidaban en la presión inspiratoria máxima (PIM y en la calidad de la vida entre pacientes mayores de la clínica de reposo. Dividieron a la población del estudio en dos grupos: grupo experimental EG. (n=21,76.48 2.12 años y grupo de control CG (n=13, 75.69 2.26 años. La calidad de la Organización Mundial de la Salud del cuestionario del grupo de la vida(WHOQOL-100 fue utilizada para evaluar la calidad de la vida de los temas. Un Manovacuometer (analógico, con un intervalo operacional - de 150 a

  17. Nonlinear analysis of wiggler-imperfections in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Freund, H.P. [Naval Research Lab., Washington, DC (United States); Yu, L.H. [Brookhaven National Lab., Upton, NY (United States)

    1995-12-31

    We present an analysis of the effect of wiggler imperfections in FELs using a variety of techniques. Our basic intention is to compare wiggler averaged nonlinear simulations to determine the effect of various approximations on the estimates of gain degradation due to wiggler imperfections. The fundamental assumption in the wiggler-averaged formulations is that the electrons are described by a random walk model, and an analytic representation of the orbits is made. This is fundamentally different from the approach taken for the non-wiggler-averaged formulation in which the wiggler imperfections are specified at the outset, and the orbits are integrated using a field model that is consistent with the Maxwell equations. It has been conjectured on the basis of prior studies using the non-wiggler-averaged formalism that electrons follow a {open_quotes}meander line{close_quotes} through the wiggler governed by the specific imperfections; hence, the electrons behave more as a ball-in-groove than as a random walk. This conjecture is tested by comparison of the wiggler-averaged and non-wiggler-averaged simulations. In addition, two different wiggler models are employed in the non-wiggler-averaged simulation: one based upon a parabolic pole face wiggler which is not curl and divergence free in the presence of wiggler imperfections, and a second model in which the divergence and z-component of the curl vanish identically. This will gauge the effect of inconsistencies in the wiggler model on the estimation of the effect of the imperfections. Preliminary results indicate that the inconsistency introduced by the non-vanishing curl and divergence result in an overestimation of the effect of wiggler imperfections on the orbit. The wiggler-averaged simulation is based upon the TDA code, and the non-wiggler-averaged simulation is a variant of the ARACHNE and WIGGLIN codes called MEDUSA developed to treat short-wavelength Gauss-Hermite modes.

  18. Clinical features and management of cavernous and venous angiomas in the head

    International Nuclear Information System (INIS)

    Tokunaga, Koji; Date, Isao

    2011-01-01

    Cerebral cavernous angiomas consist of well-circumscribed collections of thin-walled sinusoidal vascular channels lacking the intervening brain tissue. They are present in 0.4-0.8% of the population, and can occur in a sporadic or familial form. Most common symptoms are seizures, hemorrhage, and focal neurological deficits. The annual bleeding rate of the patient is reported to be 0.25%-20%. High-resolution magnetic resonance imaging (MRI) is a useful diagnostic tool with a high degree of sensitivity and specificity. Microsurgical excision of the lesion is a good treatment choice for cavernous angiomas in the brain, even in the brainstem. Although stereotactic radiosurgery may reduce the incidence of rebleeding and the frequency of seizures, its indication should be carefully investigated because of the relatively high rate of radiation-induced side effects. Less frequently, cavernous angiomas can be located at the extra-axial regions of the head, which include the cavernous sinus, the orbit, and the cranial nerves. Cavernous angiomas in the cavernous sinus pose a neurosurgical challenge due to the high vascularity and involvement of the neurovascular structures, and stereotactic radiosurgery is considered as an additional option. Surgical resection is recommended for symptomatic cavernous angiomas in the orbit; however, the rate of complications after resection is not necessarily low for cavernous angiomas within the apex. Venous angiomas are anomalies of normal venous drainage, which show characteristic appearance of the drainage system in the late phase of angiography (caput medusae). They are found either alone or in combination with other vascular malformations. Conservative treatment is recommended except for patients with a large hematoma or with a coexisting cavernous angioma. (author)

  19. Cytotoxic effects of some animal and vegetable extracts and some chemicals on liver and colon carcinoma and myosarcoma

    International Nuclear Information System (INIS)

    Bayazit, Vahdettin

    2004-01-01

    To study, the cytotoxic effects of some biological and chemical agents on G, S, G, M and G phases of liver and colon carcinomas and myosarcoma cells obtained with chemical carcinogens dimethylbenzanthracene (Dmba) and cadmium chloride. Eight rabbit livers, colon carcinoma and myosarcoma cell lines were obtained by injection of Dmba in the Biology Laboratory, of the University of Dumlupinar, Kutahya, Turkey between January 2001 and June 2003. All lines were grown at 37degrees celsius and 5% carbon dioxide in sterile RPMI-1640 medium with 10% fetal bovine serum after addition of glutamate, penicillin (50 units/ml) and streptomycin (50 ug/ml) (complete medium). Cells were grown on standard tissue culture plastic flasks to 80% confluence and passed by trypsinization. Tortoise (Testudo graeca) shell, sponge (Geodia cydonium), medusa (Aurelia aurita), meat flies (Calliphora erythrocephala) larva, frog (Rana ridibunda) larva and juniper (Juniperus communis) berry extracts killed a large amount of the liver and colon carcinomas and the myosarcoma cells in G2, M and G0 phases (p<0.01). The mistletoe (Viscum album) extract had more effect in only the G0 phase (p<0.05). Genistein, genistin, glycitein, glycitin, daitzein and daitzin have significantly decreased in the cancer cells tests, particularly, genistein and daitzein caused the apoptotic effect in G2, M and G0 phases (p<0.01). Cesium chloride, a mixture of cesium chloride with magnesium chloride had the most effect on tumor cells (p<0.01). AzhexSi, Azhex-AzhepSi, Et-Azhex-AzhepSi, AzhepSi, Hexamine and DL 54 have been inhibited in various levels of the cancer cells (p<0.05, p<0.01). This data suggest that some biological extracts and chemicals tested may be useful chemotherapeutic agents to inhibit the growth of cancer cells. This study sheds some light for new anti cancerogenic experiments preventing various cancers on humans. (author)

  20. Determination of the stability constants of lanthanum, praseodymium, europium, erbium and lutetium complexes with chloride ions

    International Nuclear Information System (INIS)

    Fernandez R, E.

    2008-01-01

    The stability constants of La 3+ , Pr 3+ , Eu 3+ , Er 3+ and Lu 3+ chloride complexes were determined in perchloric acid media using a liquid-liquid extraction method. The dinonyl napthalene sulfonic acid in n-heptane was used as extractant. The lanthanide (Ln) concentrations were measured by a radiochemical (Eu and Lu) and a spectrophotometric (La, Pr, and Er) methods. In the last method, xylenol orange was used for the determinations at ph 6. The stability constants of lanthanum, praseodymium, erbium and lutetium chloride complexes were determined in 2, 3 and 4 M ionic strength and europium in 1, 2 and 3 M, at 303 K. The fitting of experimental data to the equations for the calculation of the stability constants, was carry out considering both one chemical species (LnCl 2+ ) or two chemical species (LnCl 2+ and LnCl 2 + ). The Specific Ion Interaction Theory was applied to the values of log β I Ln , Cl and the first stability constants at zero ionic strength were calculated by extrapolation. The same theory could not be applied to the log β I Ln , 2Cl , due to its low abundance and the values determined for the stability constants were similar. The distribution diagrams of the chemical species were obtained using the program MEDUSA and considering log β I Ln , CI , log β I Ln , 2CI values obtained in this work and the hydrolysis constants taken from the literature. The lanthanide chloride complexes are present in solution at specific conditions of ionic strength, concentration and in the absence of hydrolysis. The log β I Ln , Cl data were related to the charge density and the corresponding equations were obtained. These equations could be used to determine the stability constants along the lanthanide series. (Author)

  1. Abstracts of the Annual Meeting of Planetary Geologic Mappers, San Antonio, TX, 2009

    Science.gov (United States)

    Bleamaster, Leslie F., III (Editor); Tanaka, Kenneth L.; Kelley, Michael S.

    2009-01-01

    Topics covered include: Geologic Mapping of the Beta-Atla-Themis (BAT) Region of Venus: A Progress Report; Geologic Map of the Snegurochka Planitia Quadrangle (V-1): Implications for Tectonic and Volcanic History of the North Polar Region of Venus; Preliminary Geological Map of the Fortuna Tessera (V-2) Quadrangle, Venus; Geological Map of the Fredegonde (V-57) Quadrangle, Venus; Geological Mapping of the Lada Terra (V-56) Quadrangle, Venus; Geologic Mapping of V-19; Lunar Geologic Mapping: A Preliminary Map of a Portion of the LQ-10 ("Marius") Quadrangle; Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schr dinger Basin; Geologic Mapping along the Arabia Terra Dichotomy Boundary: Mawrth Vallis and Nili Fossae, Mars; Geologic Mapping Investigations of the Northwest Rim of Hellas Basin, Mars; Geologic Mapping of the Meridiani Region of Mars; Geology of a Portion of the Martian Highlands: MTMs -20002, -20007, -25002 and -25007; Geologic Mapping of Holden Crater and the Uzboi-Ladon-Morava Outflow System; Mapping Tyrrhena Patera and Hesperia Planum, Mars; Geologic Mapping of Athabaca Valles; Geologic Mapping of MTM -30247, -35247 and -40247 Quadrangles, Reull Vallis Region, Mars Topography of the Martian Impact Crater Tooting; Mars Structural and Stratigraphic Mapping along the Coprates Rise; Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan; Geology of the Southern Utopia Planitia Highland-Lowland Boundary Plain: Second Year Results and Third Year Plan; Mars Global Geologic Mapping: About Half Way Done; New Geologic Map of the Scandia Region of Mars; Geologic Mapping of the Medusae Fossae Formation on Mars and the Northern Lowland Plains of Venus; Volcanism on Io: Insights from Global Geologic Mapping; and Planetary Geologic Mapping Handbook - 2009.

  2. Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

    Science.gov (United States)

    Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

    2010-09-01

    River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

  3. Impact of whole-genome duplication events on diversification rates in angiosperms.

    Science.gov (United States)

    Landis, Jacob B; Soltis, Douglas E; Li, Zheng; Marx, Hannah E; Barker, Michael S; Tank, David C; Soltis, Pamela S

    2018-03-01

    Polyploidy or whole-genome duplication (WGD) pervades the evolutionary history of angiosperms. Despite extensive progress in our understanding of WGD, the role of these events in promoting diversification is still not well understood. We seek to clarify the possible association between WGD and diversification rates in flowering plants. Using a previously published phylogeny spanning all land plants (31,749 tips) and WGD events inferred from analyses of the 1000 Plants (1KP) transcriptome data, we analyzed the association of WGDs and diversification rates following numerous WGD events across the angiosperms. We used a stepwise AIC approach (MEDUSA), a Bayesian mixture model approach (BAMM), and state-dependent diversification analyses (MuSSE) to investigate patterns of diversification. Sister-clade comparisons were used to investigate species richness after WGDs. Based on the density of 1KP taxon sampling, 106 WGDs were unambiguously placed on the angiosperm phylogeny. We identified 334-530 shifts in diversification rates. We found that 61 WGD events were tightly linked to changes in diversification rates, and state-dependent diversification analyses indicated higher speciation rates for subsequent rounds of WGD. Additionally, 70 of 99 WGD events showed an increase in species richness compared to the sister clade. Forty-six of the 106 WGDs analyzed appear to be closely associated with upshifts in the rate of diversification in angiosperms. Shifts in diversification do not appear more likely than random within a four-node lag phase following a WGD; however, younger WGD events are more likely to be followed by an upshift in diversification than older WGD events. © 2018 Botanical Society of America.

  4. Selective suppression of in situ proliferation of scyphozoan polyps by biofouling

    International Nuclear Information System (INIS)

    Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

    2017-01-01

    An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7–8 months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. - Highlights: • Biofouling selectively controls in situ proliferation of scyphozoan polyps • The contribution

  5. Range shortening, radiation transport, and Rayleigh-Taylor instability phenomena in ion-beam-driven inertial-fusion-reactor-size targets: Implosion, ignition, and burn phases

    International Nuclear Information System (INIS)

    Long, K.A.; Tahir, N.A.

    1987-01-01

    In this paper we present an analysis of the theory of the energy deposition of ions in cold materials and hot dense plasmas together with numerical calculations for heavy and light ions of interest to ion-beam fusion. We have used the gorgon computer code of Long, Moritz, and Tahir (which is an extension of the code originally written for protons by Nardi, Peleg, and Zinamon) to carry out these calculations. The energy-deposition data calculated in this manner has been used in the design of heavy-ion-beam-driven fusion targets suitable for a reactor, by its inclusion in the medusa code of Christiansen, Ashby, and Roberts as extended by Tahir and Long. A number of other improvements have been made in this code and these are also discussed. Various aspects of the theoretical analysis of such targets are discussed including the calculation of the hydrodynamic stability, the hydrodynamic efficiency, and the gain. Various different target designs have been used, some of them new. In general these targets are driven by Bi + ions of energy 8--12 GeV, with an input energy of 4--6.5 MJ, with output energies in the range 600--900 MJ, and with gains in the range 120--180. The peak powers are in the range of 500--750 TW. We present detailed calculations of the ablation, compression, ignition, and burn phases. By the application of a new stability analysis which includes ablation and density-gradient effects we show that these targets appear to implode in a stable manner. Thus the targets designed offer working examples suited for use in a future inertial-confinement fusion reactor

  6. Towards continuous global measurements and optimal emission estimates of NF3

    Science.gov (United States)

    Arnold, T.; Muhle, J.; Salameh, P.; Harth, C.; Ivy, D. J.; Weiss, R. F.

    2011-12-01

    We present an analytical method for the continuous in situ measurement of nitrogen trifluoride (NF3) - an anthropogenic gas with a global warming potential of ~16800 over a 100 year time horizon. NF3 is not included in national reporting emissions inventories under the United Nations Framework Convention on Climate Change (UNFCCC). However, it is a rapidly emerging greenhouse gas due to emission from a growing number of manufacturing facilities with increasing output and modern end-use applications, namely in microcircuit etching, and in production of flat panel displays and thin-film photovoltaic cells. Despite success in measuring the most volatile long lived halogenated species such as CF4, the Medusa preconcentration GC/MS system of Miller et al. (2008) is unable to detect NF3 under remote operation. Using altered techniques of gas separation and chromatography after initial preconcentration, we are now able to make continuous atmospheric measurements of NF3 with average precisions NF3 produced. Emission factors are shown to have reduced over the last decade; however, rising production and end-use have caused the average global atmospheric concentration to double between 2005 and 2011 i.e. half the atmospheric NF3 present today originates from emissions after 2005. Finally we show the first continuous in situ measurements from La Jolla, California, illustrating how global deployment of our technique could improve the temporal and spatial scale of NF3 'top-down' emission estimates over the coming years. These measurements will be important for independent verification of emissions should NF3 be regulated under a new climate treaty.

  7. A Parallel Processing Algorithm for Remote Sensing Classification

    Science.gov (United States)

    Gualtieri, J. Anthony

    2005-01-01

    A current thread in parallel computation is the use of cluster computers created by networking a few to thousands of commodity general-purpose workstation-level commuters using the Linux operating system. For example on the Medusa cluster at NASA/GSFC, this provides for super computing performance, 130 G(sub flops) (Linpack Benchmark) at moderate cost, $370K. However, to be useful for scientific computing in the area of Earth science, issues of ease of programming, access to existing scientific libraries, and portability of existing code need to be considered. In this paper, I address these issues in the context of tools for rendering earth science remote sensing data into useful products. In particular, I focus on a problem that can be decomposed into a set of independent tasks, which on a serial computer would be performed sequentially, but with a cluster computer can be performed in parallel, giving an obvious speedup. To make the ideas concrete, I consider the problem of classifying hyperspectral imagery where some ground truth is available to train the classifier. In particular I will use the Support Vector Machine (SVM) approach as applied to hyperspectral imagery. The approach will be to introduce notions about parallel computation and then to restrict the development to the SVM problem. Pseudocode (an outline of the computation) will be described and then details specific to the implementation will be given. Then timing results will be reported to show what speedups are possible using parallel computation. The paper will close with a discussion of the results.

  8. Towards a global network of gamma-ray detector calibration facilities

    Science.gov (United States)

    Tijs, Marco; Koomans, Ronald; Limburg, Han

    2016-09-01

    Gamma-ray logging tools are applied worldwide. At various locations, calibration facilities are used to calibrate these gamma-ray logging systems. Several attempts have been made to cross-correlate well known calibration pits, but this cross-correlation does not include calibration facilities in Europe or private company calibration facilities. Our aim is to set-up a framework that gives the possibility to interlink all calibration facilities worldwide by using `tools of opportunity' - tools that have been calibrated in different calibration facilities, whether this usage was on a coordinated basis or by coincidence. To compare the measurement of different tools, it is important to understand the behaviour of the tools in the different calibration pits. Borehole properties, such as diameter, fluid, casing and probe diameter strongly influence the outcome of gamma-ray borehole logging. Logs need to be properly calibrated and compensated for these borehole properties in order to obtain in-situ grades or to do cross-hole correlation. Some tool providers provide tool-specific correction curves for this purpose. Others rely on reference measurements against sources of known radionuclide concentration and geometry. In this article, we present an attempt to set-up a framework for transferring `local' calibrations to be applied `globally'. This framework includes corrections for any geometry and detector size to give absolute concentrations of radionuclides from borehole measurements. This model is used to compare measurements in the calibration pits of Grand Junction, located in the USA; Adelaide (previously known as AMDEL), located in Adelaide Australia; and Stonehenge, located at Medusa Explorations BV in the Netherlands.

  9. LLE 1994 annual report, October 1993--September 1994

    International Nuclear Information System (INIS)

    1995-01-01

    This is the 1994 annual report for the University of Rochester, Laboratory for Laser Energetics. The report is presented as a series of research type reports. The titles emphasize the breadth of work carried out. They are: stability analysis of unsteady ablation fronts; characterization of laser-produced plasma density profiles using grid image refractometry; transport and sound waves in plasmas with light and heavy ions; three-halves-harmonic radiation from long-scale-length plasmas revisited; OMEGA upgrade status report; target imaging and backlighting diagnosis; effect of electron collisions on ion-acoustic waves and heat flow; particle-in-cell code simulations of the interaction of gaussian ultrashort laser pulses with targets of varying initial scale lengths; characterization of thick cryogenic fuel layers: compensation for the lens effect using convergent beam interferometry; compact, multijoule-output, Nd:Glass, large-aperture ring amplifier; atomic force microscopy observation of water-induced morphological changes in Y 2 O 3 monolayer coatings; observation of longitudinal acceleration of electrons born in a high-intensity laser focus; spatial intensity nonuniformities of an OMEGA beam due to nonlinear beam propagation; calculated X-ray backlighting images of mixed imploded targets; evaluation of cosmic rays for use in the monitoring of the MEDUSA scintillator-photomultiplier diagnostic array; highly efficient second-harmonic generation of ultra-intense Nd:Glass laser pulses multiple cutoff wave numbers of the ablative Rayleigh-Taylor instability; ultrafast, all-silicon light modulator; angular dependence of the stimulated Brillouin scattering in homogeneous plasma; femtosecond excited-state dynamics of a conjugated ladder polymer

  10. Effects of shape and stroke parameters on the propulsion performance of an axisymmetric swimmer.

    Science.gov (United States)

    Peng, Jifeng; Alben, Silas

    2012-03-01

    In nature, there exists a special group of aquatic animals which have an axisymmetric body and whose primary swimming mechanism is to use periodic body contractions to generate vortex rings in the surrounding fluid. Using jellyfish medusae as an example, this study develops a mathematical model of body kinematics of an axisymmetric swimmer and uses a computational approach to investigate the induced vortex wakes. Wake characteristics are identified for swimmers using jet propulsion and rowing, two mechanisms identified in previous studies of medusan propulsion. The parameter space of body kinematics is explored through four quantities: a measure of body shape, stroke amplitude, the ratio between body contraction duration and extension duration, and the pulsing frequency. The effects of these parameters on thrust, input power requirement and circulation production are quantified. Two metrics, cruising speed and energy cost of locomotion, are used to evaluate the propulsion performance. The study finds that a more prolate-shaped swimmer with larger stroke amplitudes is able to swim faster, but its cost of locomotion is also higher. In contrast, a more oblate-shaped swimmer with smaller stroke amplitudes uses less energy for its locomotion, but swims more slowly. Compared with symmetric strokes with equal durations of contraction and extension, faster bell contractions increase the swimming speed whereas faster bell extensions decrease it, but both require a larger energy input. This study shows that besides the well-studied correlations between medusan body shape and locomotion, stroke variables also affect the propulsion performance. It provides a framework for comparing the propulsion performance of axisymmetric swimmers based on their body kinematics when it is difficult to measure and analyze their wakes empirically. The knowledge from this study is also useful for the design of robotic swimmers that use axisymmetric body contractions for propulsion.

  11. Effects of shape and stroke parameters on the propulsion performance of an axisymmetric swimmer

    International Nuclear Information System (INIS)

    Peng Jifeng; Alben, Silas

    2012-01-01

    In nature, there exists a special group of aquatic animals which have an axisymmetric body and whose primary swimming mechanism is to use periodic body contractions to generate vortex rings in the surrounding fluid. Using jellyfish medusae as an example, this study develops a mathematical model of body kinematics of an axisymmetric swimmer and uses a computational approach to investigate the induced vortex wakes. Wake characteristics are identified for swimmers using jet propulsion and rowing, two mechanisms identified in previous studies of medusan propulsion. The parameter space of body kinematics is explored through four quantities: a measure of body shape, stroke amplitude, the ratio between body contraction duration and extension duration, and the pulsing frequency. The effects of these parameters on thrust, input power requirement and circulation production are quantified. Two metrics, cruising speed and energy cost of locomotion, are used to evaluate the propulsion performance. The study finds that a more prolate-shaped swimmer with larger stroke amplitudes is able to swim faster, but its cost of locomotion is also higher. In contrast, a more oblate-shaped swimmer with smaller stroke amplitudes uses less energy for its locomotion, but swims more slowly. Compared with symmetric strokes with equal durations of contraction and extension, faster bell contractions increase the swimming speed whereas faster bell extensions decrease it, but both require a larger energy input. This study shows that besides the well-studied correlations between medusan body shape and locomotion, stroke variables also affect the propulsion performance. It provides a framework for comparing the propulsion performance of axisymmetric swimmers based on their body kinematics when it is difficult to measure and analyze their wakes empirically. The knowledge from this study is also useful for the design of robotic swimmers that use axisymmetric body contractions for propulsion. (paper)

  12. The evolution of dwarf shrubs in alpine environments: a case study of Alchemilla in Africa.

    Science.gov (United States)

    Gehrke, Berit; Kandziora, Martha; Pirie, Michael D

    2016-01-01

    Alpine and arctic environments worldwide, including high mountains, are dominated by short-stature woody plants (dwarf shrubs). This conspicuous life form asserts considerable influence on local environmental conditions above the treeline, creating its own microhabitat. This study reconstructs the evolution of dwarf shrubs in Alchemilla in the African tropical alpine environment, where they represent one of the largest clades and are among the most common and abundant plants. Different phylogenetic inference methods were used with plastid and nuclear DNA sequence markers, molecular dating (BEAST and RelTime), analyses of diversification rate shifts (MEDUSA and BAMM) and ancestral character and area reconstructions (Mesquite). It is inferred that African Alchemilla species originated following long-distance dispersal to tropical East Africa, but that the evolution of dwarf shrubs occurred in Ethiopia and in tropical East Africa independently. Establishing a timeframe is challenging given inconsistencies in age estimates, but it seems likely that they originated in the Pleistocene, or at the earliest in the late Miocene. The adaptation to alpine-like environments in the form of dwarf shrubs has apparently not led to enhanced diversification rates. Ancestral reconstructions indicate reversals in Alchemilla from plants with a woody base to entirely herbaceous forms, a transition that is rarely reported in angiosperms. Alchemilla is a clear example of in situ tropical alpine speciation. The dwarf shrub life form typical of African Alchemilla has evolved twice independently, further indicating its selective advantage in these harsh environments. However, it has not influenced diversification, which, although recent, was not rapid. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. LLE 1994 annual report, October 1993--September 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    This is the 1994 annual report for the University of Rochester, Laboratory for Laser Energetics. The report is presented as a series of research type reports. The titles emphasize the breadth of work carried out. They are: stability analysis of unsteady ablation fronts; characterization of laser-produced plasma density profiles using grid image refractometry; transport and sound waves in plasmas with light and heavy ions; three-halves-harmonic radiation from long-scale-length plasmas revisited; OMEGA upgrade status report; target imaging and backlighting diagnosis; effect of electron collisions on ion-acoustic waves and heat flow; particle-in-cell code simulations of the interaction of gaussian ultrashort laser pulses with targets of varying initial scale lengths; characterization of thick cryogenic fuel layers: compensation for the lens effect using convergent beam interferometry; compact, multijoule-output, Nd:Glass, large-aperture ring amplifier; atomic force microscopy observation of water-induced morphological changes in Y{sub 2}O{sub 3} monolayer coatings; observation of longitudinal acceleration of electrons born in a high-intensity laser focus; spatial intensity nonuniformities of an OMEGA beam due to nonlinear beam propagation; calculated X-ray backlighting images of mixed imploded targets; evaluation of cosmic rays for use in the monitoring of the MEDUSA scintillator-photomultiplier diagnostic array; highly efficient second-harmonic generation of ultra-intense Nd:Glass laser pulses multiple cutoff wave numbers of the ablative Rayleigh-Taylor instability; ultrafast, all-silicon light modulator; angular dependence of the stimulated Brillouin scattering in homogeneous plasma; femtosecond excited-state dynamics of a conjugated ladder polymer.

  14. Un acercamiento al cuento infantil desde la perspectiva de género. Estereotipos en el cuento infantil

    Directory of Open Access Journals (Sweden)

    Nuria Méndez-Garita

    2004-12-01

    Full Text Available ¿Cuáles son los papeles que desempeñan cada una de las mujeres que son parte de la sociedad? ¿Cómo exige un hombre que se comporte una mujer? ¿Habrán cambiado los estereotipos femeninos y masculinos que muy claramente nos presentan los cuentos? ¿Seguimos propiciando como personas los estereotipos? ¿Se está dando la inversión tanto en los cuentos como en nuestras vidas? A partir de mito griego de la Medusa, se introduce el tema del género y la literatura, sobre todo en aquella que se reconoce como literatura infantil. Desde la perspectiva de género, se pueden tratar diferentes tópicos, en este caso, el artículo se centra en los estereotipos y confrontan los que se derivan de la mujer ángel y la mujer demonio. A lo largo de la historia, la elaboración del mundo simbólico, del significado y del sentido han estado en las mentes de los varones, los que han configurado una representación del mundo a su imagen y semejanza. Son ellos el prototipo, patrón y medida de lo existente. En los cuentos infantiles podemos ver claramente los estereotipos impuestos por la cultura patriarcal; pero también, cómo algunos de ellos son capaces de subvertir el orden establecido. Lo más importante es que la lectura de cuentos infantiles y de la literatura en general, sirve para movernos y conmovernos como lectores; para que nos marque, porque nos interpela.

  15. A Minor Modification of Leading Edge Discriminator Circuitry with a Delay Line for Baseline Restoration of Scintillation Detectors

    International Nuclear Information System (INIS)

    Izumi, N

    2003-01-01

    Multi-channel neutron time-of-flight detector arrays LaNSA, T-ion, Medusa, and Mandala, have been used for neutron spectroscopy in inertial confinement fusion experiments. These multi-channel neutron detector arrays consist of many identical scintillation detectors (842 ∼ 1024 channel), data acquisition electronics (discriminators, time-to digital converters, and controller). Each detector element is operated in neutron counting mode. Time-of-flight of individual detected neutrons are recorded by time to digital converters. The energy of each detected neutrons is determined from its time-of-flight. The accurate time measurement (Δt ∼ 0.5 ns) and straightforward statistical features of the data obtained with these systems provides good integrity and reliability. The elements detector used in these systems are organic scintillators coupled with photo multiplier tubes. A scintillation detector operated in particle-counting mode requires finite recovery time after each detection event. The recovery time is determined by the time responses of scintillators, photo multiplier tubes, and the dead times of following discriminators and time-to digital converters. The harsh gamma ray background environment of fast ignitor experiments requires detectors that have fast recovery times. In high intensity laser experiments (I > 10 19 W/cm 2 ), strong gamma ray bursts are produced by relativistic laser plasma interactions. Prior to the neutron signal, these strong gamma ray bursts hit the detectors and interfere with the detection of following neutron signals. In these situations, the recovery time of the system after preceding gamma ray bursts is determined mainly by the base line shift of the PMT signal (due to slower decay components of scintillators ''after glow''). Discriminators cannot detect following signal pulses until the proceeding burst decays below its threshold voltage. The base line shift caused by the after glow prolongs the recovery time of the discriminators

  16. Counter-Memory, Heterochronia, and “History Painting” (After Géricault: Dierk Schmidt’s SIEV-X—On a Case of Intensified Refugee Politics

    Directory of Open Access Journals (Sweden)

    Veronica Tello

    2014-06-01

    Full Text Available This essay examines the disruption of linear time in experimental forms of “history painting” as represented by Dierk Schmidt’s SIEV-X—On a Case of Intensified Refugee Politics (2001-2005. It analyses how the aesthetics of heterochronoia—multiple temporalities—play a crucial role in the development of a new understanding of the politics of “history painting.” As Schmidt’s work reveals, a radical conception of history exists outside the “singular moment,” and in dialogue with heterogenous visual cultures (news media, art history, advertising. In attempting to understand the import of Schmidt’s work, this essay considers his methodologies for creating a heterochronous mode of history painting, particularly his anachronistic engagement with the work of Theodore Géricault and the iconic history painting, The Raft of the Medusa. Unlike previous critical responses to Schmidt’s work, this paper argues that (after Géricault the artist’s use of investigative “journalistic” methodologies for SIEV-X—On a Case of Intensified Refugee Politics do not generate an aesthetics of exposé but rather an aesthetics of “fictionalization.” This aesthetic is defined by the recalibration of documentary and speculative data as a means to reconceive the landscape of the perceptual. The findings of this research demonstrate that the use of disparate fragments—or data—to visualize otherwise diminishing historical events underpins contemporary history painting’s capacity for advancing a distinct economy of affect that circumvents the limitations of the news media and its “monopoly on reality.”

  17. Selective suppression of in situ proliferation of scyphozoan polyps by biofouling.

    Science.gov (United States)

    Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

    2017-01-30

    An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Dynamics of a fluid flow on Mars: Lava or mud?

    Science.gov (United States)

    Wilson, Lionel; Mouginis-Mark, Peter J.

    2014-05-01

    A distinctive flow deposit southwest of Cerberus Fossae on Mars is analyzed. The flow source is a ∼20 m deep, ∼12 × 1.5 km wide depression within a yardang associated with the Medusae Fossae Formation. The flow traveled for ∼40 km following topographic lows to leave a deposit on average 3-4 km wide. The surface morphology of the deposit suggests that it was produced by the emplacement of a fluid flowing in a laminar fashion and possessing a finite yield strength. We use topographic data from a digital elevation model (DEM) to model the dynamics of the motion and infer that the fluid had a Bingham rheology with a plastic viscosity of ∼1 Pa s and a yield strength of ∼185 Pa. Although the low viscosity is consistent with the properties of komatiite-like lava, the combination of values of viscosity and yield strength, as well as the surface morphology of the flow, suggests that this was a mud flow. Comparison with published experimental data implies a solids content close to 60% by volume and a grain size dominated by silt-size particles. Comparison of the ∼1.5 km3 deposit volume with the ∼0.03 km3 volume of the source depression implies that ∼98% of the flow material was derived from depth in the crust. There are similarities between the deposit studied here, which we infer to be mud, and other flow deposits on Mars currently widely held to be lavas. This suggests that a re-appraisal of many of these deposits is now in order.

  19. MARSIS data and simulation exploited using array databases: PlanetServer/EarthServer for sounding radars

    Science.gov (United States)

    Cantini, Federico; Pio Rossi, Angelo; Orosei, Roberto; Baumann, Peter; Misev, Dimitar; Oosthoek, Jelmer; Beccati, Alan; Campalani, Piero; Unnithan, Vikram

    2014-05-01

    parallel computing has been developed and tested on a Tier 0 class HPC cluster computer located at CINECA, Bologna, Italy, to produce accurate simulations for the entire MARSIS dataset. Although the necessary computational resources have not yet been secured, through the HPC cluster at Jacobs University in Bremen it was possible to simulate a significant subset of orbits covering the area of the Medusae Fossae Formation (MFF), a seeimingly soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars (e.g. Watters et al., 2007; Carter et al., 2009). Besides the MARSIS data, simulation of MARSIS surface clutter signal are included in the db to further improve its scientific value. Simulations will be available throught the project portal to end users/scientists and they will eventually be provided in the PSA/PDS archives. References: Baumann, P. On the management of multidimensional discrete data. VLDB J. 4 (3), 401-444, Special Issue on Spatial Database Systems, 1994. Carter, L. M., Campbell, B. A., Watters, T. R., Phillips, R. J., Putzig, N. E., Safaeinili, A., Plaut, J., Okubo, C., Egan, A. F., Biccari, D., Orosei, R. (2009). Shallow radar (SHARAD) sounding observations of the Medusae Fossae Formation, Mars. Icarus, 199(2), 295-302. Nouvel, J.-F., Herique, A., Kofman, W., Safaeinili, A. 2004. Radar signal simulation: Surface modeling with the Facet Method. Radio Science 39, 1013. Oosthoek, J.H.P, Flahaut J., Rossi, A. P., Baumann, P., Misev, D., Campalani, P., Unnithan, V. (2013) PlanetServer: Innovative Approaches for the Online Analysis of Hyperspectral Satellite Data from Mars, Advances in Space Research. DOI: 10.1016/j.asr.2013.07.002 Picardi, G., and 33 colleagues 2005. Radar Soundings of the Subsurface of Mars. Science 310, 1925-1928. Rossi, A. P., Baumann, P., Oosthoek, J., Beccati, A., Cantini, F., Misev, D. Orosei, R., Flahaut, J., Campalani, P., Unnithan, V. (2014),Geophys. Res. Abs., Vol. 16, #EGU2014-5149, this meeting. Watters, T. R

  20. Self-Sustained Operation of Radiation Detectors Based on Embedded Signal Processing

    International Nuclear Information System (INIS)

    Talnishnikh, Elena; Paganini, Lucia; Stegenga, Jan; Woertche, Heinrich; Limburgy, Han

    2013-06-01

    Analyzer) board. ENSA returns the nuclides activity concentrations of the gamma source under examination, in real time and in the field. The analysis, aimed at nuclear fingerprinting, is based on a Full Spectrum Analysis method developed by Medusa Systems BV. This analysis is usually performed for the natural occurring radionuclides: Potassium ( 40 K), Thorium ( 232 Th) and Uranium ( 238 U), but can potentially take any other nuclide into account. By embedding the data analysis in the sensor device, one creates a fully integrated system. When equipped with a local user interface, the device becomes a portable system that provides highly accurate feedback in the field. With wireless communication, a self-sustained system featuring long term stable operation for environmental monitoring is created. (authors)

  1. Cantar e seguir a canção ou para não dizer que não esgrimi a palavra: guerra de sentidos e estética da contestação nas canções de protesto em Teresina (1975-1985 * War of senses and aesthetic of refusal in the protest songs in Teresina (1975-1985

    Directory of Open Access Journals (Sweden)

    PAULO RICARDO MUNIZ SILVA

    2014-02-01

    Full Text Available Resumo: A música de protesto, categoria já consolidada no âmbito dos estudos sobre música brasileira, marcou a produção musical em Teresina, a capital do Estado do Piauí, durante a década de 1970. Neste contexto, o Festival Estudantil de Música do Piauí (FEMPI, e o Festival do Parque Piauí (FESPAPI, ambos ocorridos entre as décadas de 1970 e 1980, tiveram importância fundamental para a constituição deste quadro histórico. Responsáveis pela popularização de expressivos nomes da arte piauiense, tais como Geraldo Brito, Zé Rodrigues, João Berchmans, Achylles Costa Júnior e Williams Costa, estes festivais acabariam por gerar uma cultura musical de protesto, universo no interior do qual se destacam músicas como Biotema, Arames e Fuzis, Medusa e Represália. O propósito do presente artigo é, apoiado na análise das letras das músicas e, bem como, com o recurso à História Oral, re-conhecer este período e este ambiente da história da música piauiense.Palavras-chave: Música de protesto – Festivais – Piauí. Abstract: The protest song, a consolidated category of studies on Brazilian music, marked the music production in Teresina, the capital of Piauí State, during the 1970s. In this context, the “Festival Estudantil de Música do Piauí” [Piauí Student Music Festival] (FEMPI, and the “Festival do Parque Piauí” [Piauí Park Festival] (FESPAPI, both of which occurred between the 1970’s and 1980’s, were crucial for the formation of this historical framework. Expressive names in the Piauí art scene, such as Geraldo Brito, Zé Rodrigues, João Berchmans, Achylles Costa Júnior and Williams Costa, were popularized by these festivals that would eventually generate a musical culture of protest, within a universe in which stands out songs like “Biotema”, “Arames e Fuzis”, “Medusa” and “Represália”. The aim of this article is to re-discover this environment and this period of piauiense music

  2. Possible sea sediments due to glaciofluvial activity in Elysium Planitia, Mars

    Science.gov (United States)

    Nussbaumer, J.

    Observations of fluvial morphologies in southern Elysium Planitia strongly supports the hypothesis that water substantially affected this region during the relatively recent geologic past. As of yet, however, the extent of a standing body of water has been speculative. The observation of zig-zag features potentially analogous to those observed near the Wadden Sea on Earth [see 1] may help show in more detail the origin, activity, and fate of water in this region of Mars. These terrestrial analogs could constrain environmental scenarios concerning the formation of these features. We present a geomorphologic map of central Elysium Planitia, that aids in our interpretation of potentially site-specific depositional/erosional morphologies. Positive relief zig-zag features within the Medusae Fossae Formation (Themis Image V05875001) resemble similar structures on Earth observed at shorelines of flat regions. Glaciofluvial activity is indicated by linear features resembling straight glacial flutings, which could form aeolian yardangs subsequently. The flutings are associated with branches of inverted fluvial channels (Images Themis V05588002, MOC e1800307). Their excavated positive relief (height ~40 m) indicates, that the adjacent material was eroded by sublimation or aeolian activity. The channels possibly resemble ice marginal channels. A high resolution Digital Terrain Model of one of the channels suggests, that one channel is possibly running upslope. Fluvial processes could have operated at one location at one time, and glacial processes at another location at another time [2]. A glacial drainage system [see 3] is a possible terrestrial analog for one inverted fluvial channel on Mars (Themis Image V05875001). Flutings occur on the foreland of many glaciers and their length may provide important evidence for rapid advance over substantial distances. Flutings are the product of subglacial erosion and transport processes [4]. By assigning the different environmental

  3. FULVUE: Far Ultraviolet Universal Explorer

    Science.gov (United States)

    White, David L.; Cross, Eugene W.

    1997-10-01

    This is a concept study for a proposal to NASA/GSFC for a medium class Explorer Mission. It is designed to replace a prior SBIR Phase I design for NASA/MSFC for a Lunar far-UV survey telescope done in 1994 - 1995 for the Pathfinder Program (by the authors for I.S.E., under M. E. Nein, MSFC). A full investigation by project scientist D. L. White as to the most desirable mission science for a Lunar-based UV telescope, resulted in the decision to do a universal survey of the most interesting lines in the Lyman alpha forest, especially the O VI doublet lines around 103.2/103.8 nm. A telescope was designed by the authors incorporating a multiple instrument pod (MEDUSA), and a unique optical train featuring a selectable element secondary mirror module, with a special high resolution mode debuting a new optical design, all by chief optical engineer E. W. Cross. Special thanks go to chief spacecraft engineer T. L. Kessler for all packaging and integration of the telescope, its attendant systems, and the entire mission, including the launch interface and all presentations. In this incarnation, the basic concept has been converted by D. L. White into a free flyer designed for at least a LEO. In reconfiguring the original concept in the order to accomplish the original mission science goals, it has been necessary to take a fresh approach in order to fit the largest feasible Explorer Class Fairing (10L). In addition, the reconsideration of the mission science and the performance level available from the prior mission's optics, the authors decided to push the limits of the possible in the pursuit of excellence and choose two exceptional optical designs, augment them, and integrate them into the same limited envelope, while not sacrificing performance, communications, power, control, or serviceability. This we have kept close to focus throughout our pursuit of the mission science, which we hold foremost. We see a great need to bring the lessons learned at other portions of the

  4. Multiple Continental Radiations and Correlates of Diversification in Lupinus (Leguminosae): Testing for Key Innovation with Incomplete Taxon Sampling

    Science.gov (United States)

    Drummond, Christopher S.; Eastwood, Ruth J.; Miotto, Silvia T. S.; Hughes, Colin E.

    2012-01-01

    Replicate radiations provide powerful comparative systems to address questions about the interplay between opportunity and innovation in driving episodes of diversification and the factors limiting their subsequent progression. However, such systems have been rarely documented at intercontinental scales. Here, we evaluate the hypothesis of multiple radiations in the genus Lupinus (Leguminosae), which exhibits some of the highest known rates of net diversification in plants. Given that incomplete taxon sampling, background extinction, and lineage-specific variation in diversification rates can confound macroevolutionary inferences regarding the timing and mechanisms of cladogenesis, we used Bayesian relaxed clock phylogenetic analyses as well as MEDUSA and BiSSE birth–death likelihood models of diversification, to evaluate the evolutionary patterns of lineage accumulation in Lupinus. We identified 3 significant shifts to increased rates of net diversification (r) relative to background levels in the genus (r = 0.18–0.48 lineages/myr). The primary shift occurred approximately 4.6 Ma (r = 0.48–1.76) in the montane regions of western North America, followed by a secondary shift approximately 2.7 Ma (r = 0.89–3.33) associated with range expansion and diversification of allopatrically distributed sister clades in the Mexican highlands and Andes. We also recovered evidence for a third independent shift approximately 6.5 Ma at the base of a lower elevation eastern South American grassland and campo rupestre clade (r = 0.36–1.33). Bayesian ancestral state reconstructions and BiSSE likelihood analyses of correlated diversification indicated that increased rates of speciation are strongly associated with the derived evolution of perennial life history and invasion of montane ecosystems. Although we currently lack hard evidence for “replicate adaptive radiations” in the sense of convergent morphological and ecological trajectories among species in different

  5. Determination of the stability constants of lanthanum, praseodymium, europium, erbium and lutetium complexes with chloride ions; Determinacion de las constantes de estabilidad de los complejos de lantano, praseodimio, europio, erbio y lutecio con iones cloruro

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, E [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2008-07-01

    The stability constants of La{sup 3+}, Pr{sup 3+}, Eu{sup 3+}, Er{sup 3+} and Lu{sup 3+} chloride complexes were determined in perchloric acid media using a liquid-liquid extraction method. The dinonyl napthalene sulfonic acid in n-heptane was used as extractant. The lanthanide (Ln) concentrations were measured by a radiochemical (Eu and Lu) and a spectrophotometric (La, Pr, and Er) methods. In the last method, xylenol orange was used for the determinations at ph 6. The stability constants of lanthanum, praseodymium, erbium and lutetium chloride complexes were determined in 2, 3 and 4 M ionic strength and europium in 1, 2 and 3 M, at 303 K. The fitting of experimental data to the equations for the calculation of the stability constants, was carry out considering both one chemical species (LnCl{sup 2+}) or two chemical species (LnCl{sup 2+} and LnCl{sub 2}{sup +}). The Specific Ion Interaction Theory was applied to the values of log {beta}{sup I}{sub Ln},{sub Cl} and the first stability constants at zero ionic strength were calculated by extrapolation. The same theory could not be applied to the log {beta}{sup I}{sub Ln},{sub 2Cl}, due to its low abundance and the values determined for the stability constants were similar. The distribution diagrams of the chemical species were obtained using the program MEDUSA and considering log {beta}{sup I}{sub Ln},{sub CI}, log {beta}{sup I}{sub Ln},{sub 2CI} values obtained in this work and the hydrolysis constants taken from the literature. The lanthanide chloride complexes are present in solution at specific conditions of ionic strength, concentration and in the absence of hydrolysis. The log {beta}{sup I}{sub Ln},{sub Cl} data were related to the charge density and the corresponding equations were obtained. These equations could be used to determine the stability constants along the lanthanide series. (Author)

  6. Ideas. A History: From Fire to Freud. 2. ed.; Ideen. Eine Kulturgeschichte von der Entdeckung des Feuers bis zur Moderne

    Energy Technology Data Exchange (ETDEWEB)

    Watson, P.

    2005-07-01

    Gebiet auf der Landkarte, und das Experiment als Motor aller Entwicklung. Wie schon in seinem erfolgreichen Standardwerk 'Das Laecheln der Medusa' ueber die Ideen des 20. Jahrhunderts gelingt es dem begnadeten Wissensvermittler, den Leser in den Kosmos des Denkens und Erfindens zu locken. Voller Staunen verfolgt man das Auftauchen und Verschwinden von Ideen, Denkern und Kulturen, erkennt ungeahnte Zusammenhaenge und sieht schliesslich die eigene Welt als Produkt eines gewaltigen Prozesses aus Mut, Erfindungsgeist und Erkenntnislust. (orig.)

  7. Atmospheric histories and growth trends of C4F10, C5F12, C6F14, C7F16 and C8F18

    Directory of Open Access Journals (Sweden)

    R. F. Weiss

    2012-05-01

    Full Text Available Atmospheric observations and trends are presented for the high molecular weight perfluorocarbons (PFCs: decafluorobutane (C4F10, dodecafluoropentane (C5F12, tetradecafluorohexane (C6F14, hexadecafluoroheptane (C7F16 and octadecafluorooctane (C8F18. Their atmospheric histories are based on measurements of 36 Northern Hemisphere and 46 Southern Hemisphere archived air samples collected between 1973 to 2011 using the Advanced Global Atmospheric Gases Experiment (AGAGE "Medusa" preconcentration gas chromatography-mass spectrometry systems. A new calibration scale was prepared for each PFC, with estimated accuracies of 6.8% for C4F10, 7.8% for C5F12, 4.0% for C6F14, 6.6% for C7F16 and 7.9% for C8F18. Based on our observations the 2011 globally averaged dry air mole fractions of these heavy PFCs are: 0.17 parts-per-trillion (ppt, i.e., parts per 1012 for C4F10, 0.12 ppt for C5F12, 0.27 ppt for C6F14, 0.12 ppt for C7F16 and 0.09 ppt for C8F18. These atmospheric mole fractions combine to contribute to a global average radiative forcing of 0.35 mW m−2, which is 6% of the total anthropogenic PFC radiative forcing (Montzka and Reimann, 2011; Oram et al., 2012. The growth rates of the heavy perfluorocarbons were largest in the late 1990s peaking at 6.2 parts per quadrillion (ppq, i.e., parts per 1015 per year (yr for C4F10, at 5.0 ppq yr−1 for C5F12 and 16.6 ppq yr−1 for C6F14 and in the early 1990s for C7F16 at 4.7 ppq yr−1 and in the mid 1990s for C8F18 at 4.8 ppq yr−1. The 2011 globally averaged mean atmospheric growth rates of these PFCs are subsequently lower at 2.2 ppq yr−1 for C4F10, 1.4 ppq yr−1 for C5F12, 5.0 ppq yr−1 for C6F14, 3.4 ppq yr−1 for C7F16 and 0.9 ppq yr−1 for C8F18. The more recent slowdown in the growth rates suggests that emissions are declining as compared to the 1980s and 1990s.

  8. Part I. Development of a concept inventory addressing students' beliefs and reasoning difficulties regarding the greenhouse effect, Part II. Distribution of chlorine measured by the Mars Odyssey Gamma Ray Spectrometer

    Science.gov (United States)

    Keller, John Michael

    chlorine on Mars measured by the Mars Odyssey Gamma Ray Spectrometer (GRS). The distribution of chlorine is heterogeneous across the surface, with a concentration of high chlorine centered over the Medusa Fossae Formation. The distribution of chlorine correlates positively with hydrogen and negatively with silicon and thermal inertia. Four mechanisms (aeolian, volcanic, aqueous, and hydrothermal) are discussed as possible factors influencing the distribution of chlorine measured within the upper few tens of centimeters of the surface.

  9. Characterization of groundwater composition in Punjab state with special emphasis on uranium content, speciation and mobility

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajay; Rout, Sabyasachi; Mishra, Manish K.; Ravi, P.M. [Bhabha Atomic Reseach Centre, Mumbai (India). Health Physics Div.; Tripathi, R.M. [Bhabha Atomic Reseach Centre, Mumbai (India). Environmental Assessment Div.; Ghosh, A.K. [Bhabha Atomic Reseach Centre, Mumbai (India). Health, Safety and Environmental Group

    2014-04-01

    Groundwaters (borewell and handpump) were sampled from two districts (Bathinda and Mansa) of Punjab state and analyzed for their major ionic concentrations and uranium isotope compositions in order to assess the possible origins of the waters and water-rock interactions that occurred in the deep aquifer system. The major ionic concentrations of waters were plotted on a Piper diagram and grouped into four dominant hydrochemical facies as (Na+K)-SO{sub 4}+Cl type (69%-73%), (Ca+Mg)-SO{sub 4}+Cl type (6% - 21%), (Ca+Mg)-HCO{sub 3} type (4% - 6%) and (Na+K)-HCO{sub 3} type (2% - 19%). It was observed that mobility of uranium in groundwater was very much influenced by TDS (total dissolved solids). To investigate the various mechanisms for deriving the elevated uranium concentrations in groundwater, {sup 234}U/{sup 238}U activity ratios (ARs) were calculated using the determined activity levels of {sup 234}U and {sup 238}U. The mean ARs was found to be near unity (i.e. secular equilibrium) in the study regions confirmed that uranium in groundwaters was mainly resulted from its host/parent rocks through weathering processes. The concentration of HCO{sub 3}{sup -} in ground water showed one order of magnitude higher than the total dissolved SiO{sub 2} indicates that carbonate weathering was the dominant process due to major water-rock interaction. The uranium speciation in groundwaters was investigated by an equilibrium model calculation using MEDUSA (make equilibrium diagrams using sophisticated algorithms) under the influence of redox conditions and complexant concentration. At the observed range of pH values, the predominant redox speciation of uranium was observed as hydroxo-carbonato complexes of (UO{sub 2}){sub 2}(CO{sub 3})(OH){sub 3}{sup -} and hydroxyl complexes of UO{sub 2}(OH){sub 3}{sup -} which might be caused for increasing the solubility of uranium. Due to very low concentration of phosphate in groundwater, its effects on U(VI)-aqueous speciation was

  10. Estuarine and marine diets of out-migrating Chinook Salmon smolts in relation to local zooplankton populations, including harmful blooms

    Science.gov (United States)

    Chittenden, C. M.; Sweeting, R.; Neville, C. M.; Young, K.; Galbraith, M.; Carmack, E.; Vagle, S.; Dempsey, M.; Eert, J.; Beamish, R. J.

    2018-01-01

    Changes in food availability during the early marine phase of wild Chinook Salmon (O. tshawytscha) are being investigated as a cause of their recent declines in the Salish Sea. The marine survival of hatchery smolts, in particular, has been poor. This part of the Salish Sea Marine Survival Project examined the diet of young out-migrating Chinook Salmon for four consecutive years in the Cowichan River estuary and in Cowichan Bay, British Columbia, Canada. Local zooplankton communities were monitored during the final year of the study in the Cowichan River estuary, Cowichan Bay, and eastward to the Salish Sea to better understand the bottom-up processes that may be affecting Chinook Salmon survival. Rearing environment affected body size, diet, and distribution in the study area. Clipped smolts (hatchery-reared) were larger than the unclipped smolts (primarily naturally-reared), ate larger prey, spent very little time in the estuary, and disappeared from the bay earlier, likely due to emigration or mortality. Their larger body size may be a disadvantage for hatchery smolts if it necessitates their leaving the estuary prematurely to meet energy needs; the onset of piscivory began at a forklength of approximately 74 mm, which was less than the average forklength of the clipped fish in this study. The primary zooplankton bloom occurred during the last week of April/first week of May 2013, whereas the main release of hatchery-reared Chinook Salmon smolts occurs each year in mid-May-this timing mismatch may reduce their survival. Gut fullness was correlated with zooplankton biomass; however, both the clipped and unclipped smolts were not observed in the bay until the bloom of harmful Noctiluca was finished-20 days after the maximum recorded zooplankton abundance. Jellyfish medusa flourished in nearshore areas, becoming less prevalent towards the deeper waters of the Salish Sea. The sizable presence of Noctiluca and jellyfish in the zooplankton blooms may be repelling

  11. Frog: Asynchronous Graph Processing on GPU with Hybrid Coloring Model

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xuanhua; Luo, Xuan; Liang, Junling; Zhao, Peng; Di, Sheng; He, Bingsheng; Jin, Hai

    2018-01-01

    GPUs have been increasingly used to accelerate graph processing for complicated computational problems regarding graph theory. Many parallel graph algorithms adopt the asynchronous computing model to accelerate the iterative convergence. Unfortunately, the consistent asynchronous computing requires locking or atomic operations, leading to significant penalties/overheads when implemented on GPUs. As such, coloring algorithm is adopted to separate the vertices with potential updating conflicts, guaranteeing the consistency/correctness of the parallel processing. Common coloring algorithms, however, may suffer from low parallelism because of a large number of colors generally required for processing a large-scale graph with billions of vertices. We propose a light-weight asynchronous processing framework called Frog with a preprocessing/hybrid coloring model. The fundamental idea is based on Pareto principle (or 80-20 rule) about coloring algorithms as we observed through masses of realworld graph coloring cases. We find that a majority of vertices (about 80%) are colored with only a few colors, such that they can be read and updated in a very high degree of parallelism without violating the sequential consistency. Accordingly, our solution separates the processing of the vertices based on the distribution of colors. In this work, we mainly answer three questions: (1) how to partition the vertices in a sparse graph with maximized parallelism, (2) how to process large-scale graphs that cannot fit into GPU memory, and (3) how to reduce the overhead of data transfers on PCIe while processing each partition. We conduct experiments on real-world data (Amazon, DBLP, YouTube, RoadNet-CA, WikiTalk and Twitter) to evaluate our approach and make comparisons with well-known non-preprocessed (such as Totem, Medusa, MapGraph and Gunrock) and preprocessed (Cusha) approaches, by testing four classical algorithms (BFS, PageRank, SSSP and CC). On all the tested applications and

  12. Métodos de avaliação da ferrugem do álamo e eficiência de fungicidas no seu controle Evaluation method for poplar rust and its fungicide control efficiency

    Directory of Open Access Journals (Sweden)

    Louise Larissa May De Mio

    2008-10-01

    Full Text Available A ferrugem do álamo (Melampsora medusae Thuem. causa sérios prejuízos no viveiro, e seu controle é fundamental para a obtenção de muda de boa qualidade. Este trabalho teve como objetivos: i testar a eficiência de fungicidas de contato (mancozebe, cartap e oxicloreto de cobre e sistêmicos (triadimenol, tebuconazole e difenoconazole no controle da ferrugem; ii comparar métodos de avaliação para discriminar a eficiência entre os tratamentos; iii relacionar desfolha com dados de doença; e iv verificar a influência do controle da ferrugem nos parâmetros de crescimento da árvore em viveiro. O experimento foi montado em São Mateus do Sul, PR, delineado inteiramente ao acaso com 10 tratamentos (testemunha, triadimenol, mancozebe, tebuconazole, difenoconazole, cartap, oxicloreto de cobre, triadimenol-mancozebe, tebuconazole-mancozebe e triadimenol aplicados com o dobro do intervalo dos anteriores e 11 repetições. Com parcelas experimentais de 10 m de largura com quatro linhas de plantio (espaçamento entre linhas de 2,5 e entre plantas de 0,50 m, totalizando 110 parcelas com o clone Latorre. Durante dois ciclos consecutivos foram avaliados: o número de pústulas em meia folha, a % visual de doença, a severidade por parcela, a % visual de desfolha, o diâmetro à altura do peito e a altura de plantas ao final do experimento. Os produtos sistêmicos (triadimenol, tebuconazole e difenoconazole aplicados puros ou intercalados com mancozebe foram eficientes no controle da ferrugem, reduzindo o número de pústulas sobre a folha e a desfolha, o que resultou em ganho significativo no volume final das plantas. O mancozebe aplicado isoladamente também reduziu a epidemia e aumentou o volume da árvore em 42%. O produto cúprico proporcionou aumento de volume em 27%. Os métodos de avaliação utilizados diferenciaram dos tratamentos e houve correlação da doença com os danos na cultura.Poplar rust (Melampsora medusae Thuem. causes serious

  13. Determination of the ratio between phosphorus and uranium in surface waters selected in the State of Mexico

    International Nuclear Information System (INIS)

    Ordonez R, E.

    2001-01-01

    concentration it was made by means of neutron activation analysis. The physicochemical parameters diminished of value in the temporary analysis, as long as those anions and the cations didn't show a behavior defined in this same analysis, while in the analysis in depth these parameters presented minimum changes. In the modelling one for computer packages, the results of the speciation analysis chemistry, by means of the Medusa program, they revealed that the species of uranium in solution but abundant they were phosphate uranyl monoacid, tris uranyl carbonate and bis uranyl carbonate and, in smaller proportion, the species of aqueous uranyl hydroxide. The characterization of waters for the program GWW gave as a result that the facies but representative it was the bicarbonate magnesia. In the study of the quality of the one it dilutes with ends of agricultural watering, they were classified as capable for this purpose. The analysis statistical one carries out with base in the correlation coefficient whose value among the uranium and the match is moderated in three sampling points. (Author)

  14. Determination of the ratio between phosphorus and uranium in surface waters selected in the State of Mexico; Determinacion de la relacion entre fosforo y uranio en cuerpos de agua seleccionados en el Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E

    2001-07-01

    concentration it was made by means of neutron activation analysis. The physicochemical parameters diminished of value in the temporary analysis, as long as those anions and the cations didn't show a behavior defined in this same analysis, while in the analysis in depth these parameters presented minimum changes. In the modelling one for computer packages, the results of the speciation analysis chemistry, by means of the Medusa program, they revealed that the species of uranium in solution but abundant they were phosphate uranyl monoacid, tris uranyl carbonate and bis uranyl carbonate and, in smaller proportion, the species of aqueous uranyl hydroxide. The characterization of waters for the program GWW gave as a result that the facies but representative it was the bicarbonate magnesia. In the study of the quality of the one it dilutes with ends of agricultural watering, they were classified as capable for this purpose. The analysis statistical one carries out with base in the correlation coefficient whose value among the uranium and the match is moderated in three sampling points. (Author)

  15. CSAR 2014: A Benchmark Exercise Using Unpublished Data from Pharma.

    Science.gov (United States)

    Carlson, Heather A; Smith, Richard D; Damm-Ganamet, Kelly L; Stuckey, Jeanne A; Ahmed, Aqeel; Convery, Maire A; Somers, Donald O; Kranz, Michael; Elkins, Patricia A; Cui, Guanglei; Peishoff, Catherine E; Lambert, Millard H; Dunbar, James B

    2016-06-27

    The 2014 CSAR Benchmark Exercise was the last community-wide exercise that was conducted by the group at the University of Michigan, Ann Arbor. For this event, GlaxoSmithKline (GSK) donated unpublished crystal structures and affinity data from in-house projects. Three targets were used: tRNA (m1G37) methyltransferase (TrmD), Spleen Tyrosine Kinase (SYK), and Factor Xa (FXa). A particularly strong feature of the GSK data is its large size, which lends greater statistical significance to comparisons between different methods. In Phase 1 of the CSAR 2014 Exercise, participants were given several protein-ligand complexes and asked to identify the one near-native pose from among 200 decoys provided by CSAR. Though decoys were requested by the community, we found that they complicated our analysis. We could not discern whether poor predictions were failures of the chosen method or an incompatibility between the participant's method and the setup protocol we used. This problem is inherent to decoys, and we strongly advise against their use. In Phase 2, participants had to dock and rank/score a set of small molecules given only the SMILES strings of the ligands and a protein structure with a different ligand bound. Overall, docking was a success for most participants, much better in Phase 2 than in Phase 1. However, scoring was a greater challenge. No particular approach to docking and scoring had an edge, and successful methods included empirical, knowledge-based, machine-learning, shape-fitting, and even those with solvation and entropy terms. Several groups were successful in ranking TrmD and/or SYK, but ranking FXa ligands was intractable for all participants. Methods that were able to dock well across all submitted systems include MDock,1 Glide-XP,2 PLANTS,3 Wilma,4 Gold,5 SMINA,6 Glide-XP2/PELE,7 FlexX,8 and MedusaDock.9 In fact, the submission based on Glide-XP2/PELE7 cross-docked all ligands to many crystal structures, and it was particularly impressive to see

  16. Impact of the uranium (VI) speciation in mineralised urines on its extraction by calix[6]arene bearing hydroxamic groups used in chromatography columns.

    Science.gov (United States)

    Baghdadi, S; Bouvier-Capely, C; Ritt, A; Peroux, A; Fevrier, L; Rebiere, F; Agarande, M; Cote, G

    2015-11-01

    Actinides determination in urine samples is part of the analyses performed to monitor internal contamination in case of an accident or a terrorist attack involving nuclear matter. Mineralisation is the first step of any of these analyses. It aims at reducing the sample volume and at destroying all organic compounds present. The mineralisation protocol is usually based on a wet ashing step, followed by actinides co-precipitation and a furnace ashing step, before redissolution and the quantification of the actinides by the appropriate techniques. Amongst the existing methods to perform the actinides co-precipitation, alkali-earth (typically calcium) precipitation is widely used. In the present work, the extraction of uranium(VI), plutonium(IV) and americium(III) from the redissolution solutions (called "mineralised urines") on calix[6]arene columns bearing hydroxamic groups was investigated as such an extraction is a necessary step before their determination by ICP-MS or alpha spectrometry. Difficulties were encountered in the transfer of uranium(VI) from raw to mineralised urines, with yield of transfer ranging between 0% and 85%, compared to about 90% for Pu and Am, depending on the starting raw urines. To understand the origin of such a difficulty, the speciation of uranium (VI) in mineralised urines was investigated by computer simulation using the MEDUSA software and the associated HYDRA database, compiled with recently published data. These calculations showed that the presence of phosphates in the "mineralised urines" leads to the formation of strong uranyl-phosphate complexes (such as UO2HPO4) which compete with the uranium (VI) extraction by the calix[6]arene bearing hydroxamic groups. The extraction constant of uranium (VI) by calix[6]arene bearing hydroxamic groups was determined in a 0.04 mol L(-1) sodium nitrate solution (logK=4.86±0.03) and implemented in an extraction model taking into account the speciation in the aqueous phase. This model allowed to

  17. Gullies of Gorgonus Chaos

    Science.gov (United States)

    2002-01-01

    (Released 11 June 2002) The Science This fractured surface belongs to a portion of a region called Gorgonum Chaos located in the southern hemisphere of Mars. Gorgonum Chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars and lolling tongues who lived in caves. As it turns out this is indeed a fitting name for this region of Mars because it contains a high density of gullies that 'snake' their way down the walls of the troughs located in this region of chaos. Upon closer examination one finds that these gullies and alluvial deposits, initially discovered by Mars Global Surveyor, are visible on the trough walls (best seen near the bottom of the image). These gullies appear to emanate from a specific layer in the walls. The gullies have been proposed to have formed by the subsurface release of water. The Story This fractured, almost spooky-looking surface belongs to a region called Gorgonum Chaos in the southern hemisphere of Mars. Chaos is a term used for regions of Mars with distinctive areas of broken terrain like the one seen above. This area of Martian chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars, and lolling tongues, who lived in caves. The Gorgons, including famous sister Medusa, could turn a person to stone, and their writhing, snakelike locks cause revulsion to this day. Given the afflicted nature of this contorted terrain, with all of its twisted, branching channels and hard, stony-looking hills in the top half of the image, this is indeed a fitting name for this region of Mars. The name also has great appeal, because the area contains a high density of gullies that 'snake' their way down the walls of the troughs located in this region of Martian chaos. Gullies are trenches cut into the land as accelerated streams of water (or another liquid) erode the surface. To see these, click on the

  18. Optimal Electromagnetic (EM) Geophysical Techniques to Map the Concentration of Subsurface Ice and Adsorbed Water on Mars and the Moon

    Science.gov (United States)

    Stillman, D. E.; Grimm, R. E.

    2013-12-01

    dielectric spectroscopy at the Cold Regions Research and Engineering Laboratory (CRREL) permafrost tunnel in Fox, AK. We were able to detect the ice relaxation in the subsurface despite the considerable amount of subsurface unfrozen water due to the presence of montmorillonite clay and much warmer temperatures than Mars or permanently shadowed regions of the Moon. While dielectric spectroscopy can be used to determine ice and adsorbed water content it does not possess the high resolution mapping capability of a GPR. Moreover, GPR cannot detect subsurface ice content in ice-sediment mixtures as evidenced in the interpretation of the Medusae Fossae Formation. Orbital radar surveys show this unit has a low attenuation and a dielectric permittivity near 4. This allows the formation to be interpreted as ice-rich or a dry high-porosity volcanic tuff unit. Therefore, combining GPR and dielectric spectroscopy will enable high-resolution structural and volatile mapping of the subsurface. Furthermore, the addition of neutron spectroscopy would add total hydrogen abundance in the top meter. This could lead to the determination of how much hydrogen resides in ice, adsorbed water, and minerals.

  19. Why do vampires avoid mirrors? Reflections on specularity in the visual arts

    Directory of Open Access Journals (Sweden)

    Vangelis Athanassopoulos

    2012-02-01

    Full Text Available Vangelis Athanassopoulos, Ph.D. in Aesthetics, is an Associate Professor of Philosophy of Art at the Department of Visual Arts of the University Paris I Panthéon-Sorbonne in Paris, France. He is a member of the LETA (Laboratory of Theoretical and Applied Aesthetics, University Paris I, the AICA (International Association of Art Critics, and co-editor of Proteus, an online French journal on aesthetics (www.revue-proteus.com. He has published two books on postmodernism and advertising (La publicité dans l'art contemporain, 2 t., Paris: L'Harmattan, 2009 as well as several articles on modern and contemporary art. His research fields include visual semiology, philosophy of language and critical theory.This article is an attempt to organize the general axes of a research on mirror image in the visual arts, addressing the concept of specularity and its problematic status in Western aesthetics. The argument is that, paradoxically, despite the central role of reflection in the theory of representation, specularity is constantly repressed as false and dangerous. Hence the historical duplicity of the mirror in its relation to art: on the one hand it consolidates the Western system of representation while on the other it deconstructs the very principles upon which this system is erected. Literary theory and psychoanalysis enable us to focus on the ways which, in the founding myths of representation such as the ones of Narcissus and Medusa, vision, discourse and identity are articulated around reflection, relating a physical phenomenon with the mental processes defining self-consciousness. In the field of visual arts, this articulation is operated through the opposition between two different conceptions of the image, “painting-as-window” and “painting-as-mirror”. Locating this opposition in Svetlana Alpers’ reading of Las Meninas and Louis Marin's approach of the Brunelleschian optical box, we point out the discontinuity which comes to the fore

  20. Determination of the ratio between phosphorus and uranium in surface waters selected in the State of Mexico; Determinacion de la relacion entre fosforo y uranio en cuerpos de agua seleccionados en el Estado de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E

    2001-07-01

    concentration it was made by means of neutron activation analysis. The physicochemical parameters diminished of value in the temporary analysis, as long as those anions and the cations didn't show a behavior defined in this same analysis, while in the analysis in depth these parameters presented minimum changes. In the modelling one for computer packages, the results of the speciation analysis chemistry, by means of the Medusa program, they revealed that the species of uranium in solution but abundant they were phosphate uranyl monoacid, tris uranyl carbonate and bis uranyl carbonate and, in smaller proportion, the species of aqueous uranyl hydroxide. The characterization of waters for the program GWW gave as a result that the facies but representative it was the bicarbonate magnesia. In the study of the quality of the one it dilutes with ends of agricultural watering, they were classified as capable for this purpose. The analysis statistical one carries out with base in the correlation coefficient whose value among the uranium and the match is moderated in three sampling points. (Author)

  1. La proteína verde fluorescente ilumina la biociencia The Green Fluorescent Protein that glows in Bioscience

    Directory of Open Access Journals (Sweden)

    María Inés Pérez Millán

    2009-06-01

    Full Text Available La proteína verde fluorescente (o GFP, por sus siglas en inglés, Green Fluorescent Protein es una proteína producida por la medusa Aequorea victoria que emite bioluminiscencia en la zona verde del espectro visible. El gen que codifica esta proteína ha sido clonado y se utiliza habitualmente en biología molecular como marcador. Los descubrimientos relacionados a la GFP merecieron el Premio Nobel de Química 2008, en conjunto a los tres investigadores, Dres Shimomura, Chalfie y Tsien que participaron escalonadamente en dilucidar la estructura y función de la proteína. El Dr. Shimomura descubrió y estudió las propiedades de GFP, el Dr. Chalfie usando técnicas de biología molecular logró introducir el gen que codificaba para la GFP en el ADN del gusano transparente C. elegans, e inició la era de GFP como marcador de procesos en células y organismos. Finalmente el Dr. Tsien modificó la estructura de la proteína para producir moléculas que emiten luz a distintas longitudes de onda, extendiendo la paleta de colores de las proteínas. Las proteínas fluorescentes, entre las cuales se encuentra la GFP, son muy versátiles y se utilizan en diversos campos como la microbiología, ingeniería genética, fisiología, e ingeniería ambiental. Permiten ver procesos previamente invisibles, como el desarrollo de neuronas, cómo se diseminan las células cancerosas, o la contaminación de agua con arsénico, por mencionar algunos usos. Con la obtención de proteínas de muchos colores complejas redes biológicas pueden ser marcadas diferencialmente, lo que permite visualizar la biología celular en acción.Green fluorescent protein (GFP is a protein produced by the jellyfish Aequorea victoria, that emits bioluminescence in the green zone of the visible spectrum. The GFP gene has been cloned and is used in molecular biology as a marker. The three researchers that participated independently in elucidating the structure and function of this and its

  2. HFC-23 (CHF3 emission trend response to HCFC-22 (CHClF2 production and recent HFC-23 emission abatement measures

    Directory of Open Access Journals (Sweden)

    R. G. Prinn

    2010-08-01

    Full Text Available HFC-23 (also known as CHF3, fluoroform or trifluoromethane is a potent greenhouse gas (GHG, with a global warming potential (GWP of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC-22 (CHClF2, chlorodifluoromethane production. HCFC-22, an ozone depleting substance (ODS, is used extensively in commercial refrigeration and air conditioning, in the extruded polystyrene (XPS foam industries (dispersive applications and also as a feedstock in fluoropolymer manufacture (a non-dispersive use. Aside from small markets in specialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmosphere. Efforts have been made in the past two decades to reduce HFC-23 emissions, including destruction (incineration in facilities in developing countries under the United Nations Framework Convention on Climate Change's (UNFCCC Clean Development Mechanism (CDM, and by process optimization and/or voluntary incineration by most producers in developed countries. We present observations of lower-tropospheric mole fractions of HFC-23 measured by "Medusa" GC/MSD instruments from ambient air sampled in situ at the Advanced Global Atmospheric Gases Experiment (AGAGE network of five remote sites (2007–2009 and in Cape Grim air archive (CGAA samples (1978–2009 from Tasmania, Australia. These observations are used with the AGAGE 2-D atmospheric 12-box model and an inverse method to produce model mole fractions and a "top-down" HFC-23 emission history. The model 2009 annual mean global lower-tropospheric background abundance is 22.6 (±0.2 pmol mol−1. The derived HFC-23 emissions show a "plateau" during 1997–2003, followed by a rapid ~50% increase to a peak of 15.0 (+1.3/−1.2 Gg/yr in 2006. Following this peak, emissions of HFC-23 declined rapidly to 8.6 (+0.9/−1.0 Gg/yr in 2009, the lowest annual emission of the past 15 years. We derive a 1990–2008 "bottom-up" HFC-23 emission history

  3. Accumulation of metal ions by pectinates

    Science.gov (United States)

    Deiana, S.; Deiana, L.; Palma, A.; Premoli, A.; Senette, C.

    2009-04-01

    The knowledge of the mechanisms which regulate the interactions of metal ions with partially methyl esterified linear polymers of α-1,4 linked D-galacturonic acid units (pectinates), well represented in the root inner and outer apoplasm, is of great relevance to understand the processes which control their accumulation at the soil-root interface as well as their mobilization by plant metabolites. Accumulation of a metal by pectinates can be affected by the presence of other metals so that competition or distribution could be expected depending on the similar or different affinity of the metal ions towards the binding sites, mainly represented by the carboxylate groups. In order to better understand the mechanism of accumulation in the apoplasm of several metal ions, the sorption of Cd(II), Zn(II), Cu(II), Pb(II) and Cr(III) by a Ca-polygalacturonate gel, used as model of the soil-root interface, with a degree of esterification of 18% (PGAE1) and 65% (PGAE2) was studied at pH 3.0, 4.0, 5.0 and 6.0 in the presence of CaCl2 2.5 mM.. The results show that sorption increases with increasing both the initial metal concentration and pH. A similar sorption trend was evidenced for Cu(II) and Pb(II) and for Zn(II) and Cd(II), indicating that the mechanism of sorption for these two ionic couples is quite different. As an example, at pH 6.0 and an initial metal concentration equal to 2.0 mM, the amount of Cu(II) and Pb(II) sorbed was about 1.98 mg-1 of PGAE1 while that of Cd(II) and Zn(II) was about 1.2 mg-1. Cr(III) showed a rather different sorption trend and a much higher amount (2.8 mg-1of PGAE1 at pH 6.0) was recorded. The higher affinity of Cr(III) for the polysaccharidic matrix is attributable to the formation of Cr(III) polynuclear species in solution, as shown by the distribution diagrams obtained through the MEDUSA software. On the basis of these findings, the following affinity towards the PGAE1 can be assessed: Cr(III) > Cu(II) ? Pb(II) > Zn (II) ? Cd

  4. Ma'adim Vallis Estuarine Delta in Elysium Basin and Its Relevance as a Landing Site for Exobiology Exploration on Mars

    Science.gov (United States)

    Grin, E. A.; Cabrol, N. A.

    1998-01-01

    Amazonian flooded plain and chaotic material, (b) The second region is located on the western flank of Apollinaris Patera. It is surrounded by relics of deep valleys that suggest a former downstream course of Ma'adim Vallis. The geologic setting of this region (Lucus Planum) is interpreted to be an Amazonian formation composed by the middle and lower members of the Medusae Formation., c) The third region corresponds to the convergence of the west and east branches of Ma'adirn Vallis into a deep re-entrant wide gulf that penetrates about 100 km into the highland. This topographic depression is delineated by the 1000 in elevation contour. This gulf has formed an estuarine configuration centered at 3S/190W within the Elysium Basin. This configuration has favored the formation of a estuarine sedimentary delta, because of topographically controlled lateral migration. This estuarine structure is strongly dominated by the incoming supply of Ma'adim Vallis fluvial sediment extracted from Zephiria Mensae and Lucus Planum. The obtuse-angle geometry of the estuary increases the sedimentation rate, which is higher than in the course of the channel. The sediment deposition process is governed by the estuarine water circulation. The inflowing loaded fluvial water enters the estuary as a bottom current, and mixes with the relatively less-loaded water of the receiving basin. When they mixed. the inflowing fluvial material, and the landward basin circulating water generate an accumulation of highly-diversified estuarine deposit stratification. This accumulation of material is mostly centered in the transitional zone of the delta. The sediment trapping efficiency of the estuary is function of the energy balance between the inflowing fluvial water, and the ingoing basin current. The submergence of the delta by the rising of the water-level increases the estuary water-depth, and consequently the sediment entrapment is favored. The locus of sediment accumulation moves landward in the zone of

  5. Variability and Uncertainties of Key Hydrochemical Parameters for SKB Sites

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd, Willoughby on the Wolds, Loughborough (United Kingdom); Hermansson, Hans-Peter [Studsvik Nuclear AB, Nykoeping (Sweden)

    2006-12-15

    being able to characterise them thermodynamically. Geochemical modelling with the MEDUSA program and the HYDRA thermodynamic database was used to construct a set of Eh/pH diagrams for the iron and sulphur system in Forsmark groundwaters. Geochemical modelling with the PHREEQCI program was used for two purposes connected with uncertainties in key hydrochemical parameters: (i) to adjust pH to compensate for CO{sub 2} outgassing on the basis of an assumption that in situ groundwater should be at equilibrium with calcite, and (ii) to evaluate the hypothetical Eh on the basis of assumed control by Fe{sup 3+}/Fe{sup 2+}, Fe(OH)3/Fe{sup 2+} and SO{sub 4} 2-/HS- redox couples so as to assess evidence for control and buffering of redox and for reactivity of other redox sensitive parameters. These calculations were carried out with reported groundwater data from Forsmark and Simpevarp sites and also from the Aespoe HRL. It is emphasised that the purpose of these calculations is to explore and illustrate the theoretical basis of geochemical interpretations, and to understand what are the assumptions, simplifications and uncertainties in interpreting hydrochemical data especially redox and pH. Deviations of {+-}10 mV are attributable to minor differences in thermodynamic data and other model inputs. Some of the conclusions from geochemical modelling are: (i) pH data, when adjusted to compensate for CO{sub 2} outgassing, are typically 0.2 to 0.4 pH units lower than the measured values, which suggests one aspect of uncertainty in measured pH values. (ii) Most measured pH/Eh points for Forsmark are located close to the HS{sup -}/SO{sub 4} 2-line in an Eh/pH diagram, suggesting that the couple HS{sup -}/SO{sub 4} 2-controls Eh at normal SO{sub 4} 2-concentrations (above about 0.5 mM and around 5 mM). (iii) Eh calculated from the couples SO{sub 4} 2-/HS- and Fe(OH)3/Fe{sup 2+} are rather close to the measured Eh in most cases. In contrast, the Eh calculated from the Fe{sup 3+}/Fe{sup 2

  6. [Informative predation: Towards a new species concept].

    Science.gov (United States)

    Lherminier, Philippe

    2018-04-01

    We distinguish two types of predations: the predation of matter-energy equals the food chain, and the informative predation is the capture of the information brought by the sexual partners. The cell or parent consumes energy and matter to grow, multiply and produce offspring. A fixed amount of resources is divided by the number of organisms, so individual growth and numerical multiplication are limited by depletion resources of the environment. Inversely, fertilization does not destroy information, but instead produces news. The information is multiplied by the number of partners and children, since each fertilization gives rise to a new genome following a combinatorial process that continues without exhaustion. The egg does not swallow the sperm to feed, but exchange good food for quality information. With the discovery of sex, that is, 1.5 Ga ago, life added soft predation to hard predation, i.e. information production within each species to matter-energy flow between species. Replicative and informative structures are subject to two competing biological constraints: replicative fidelity promotes proliferation, but limits adaptive evolution. On the contrary, the offspring of a couple obviously cannot be a copy of both partners, they are a new production, a re-production. Sexual recombination allows the exponential enrichment of the genetic diversity, thus promoting indefinite adaptive and evolutionary capacities. Evolutionary history illustrates this: the bacteria proliferate but have remained at the first purely nutritive stage in which most of the sensory functions, mobility, defense, and feeding have experienced almost no significant novelty in three billion years. Another world appeared with the sexual management of information. Sexual reproduction actually combines two functions: multiplicative by "vertical transfer" and informative by "horizontal transfer". This distinction is very common: polypus - medusa alternations, parasite multiplication cycles, the

  7. A Tale of Two Populations

    Science.gov (United States)

    2005-03-01

    FLAMES instrument on the Very Large Telescope at Paranal. They used the MEDUSA mode, allowing to obtain no less than 130 spectra simultaneously. Twelve one-hour spectra were obtained for 17 stars of the blue population and the same number stars from the red one. These stars have magnitudes between 20 and 21, i.e., they are between 500,000 and 1 million times fainter than what can be seen with the unaided eye. The individual spectra of stars from each population were then co-added. This produced a "mean" spectrum of a blue-population star and another of a red-population. Each of these spectra represents a total of no less than 204 hours of exposure time and accordingly provides information in unrivalled detail about these stars, especially in terms of their chemical composition. The scientific outcome matches the technical achievement! From a careful study of the combined spectra, the astronomers were able to establish that - contrary to all prior expectations - the bluer stars are more "metal-rich" (by a factor two) than the redder ones. "The latter were found to have an abundance of elements more massive than helium corresponding to about 1/40 the solar abundance [2] ", explains Raffaele Gratton of INAF-Osservatorio Astronomico di Padova in Italy. "This is indeed very puzzling as current models of stars predict that the more metal-rich a star is, the redder it ought to be". Giampaolo Piotto (University of Padova, Italy), leader of the team, thinks that there is a solution to this celestial puzzle: "The only way we can explain this discrepancy is by assuming that the two populations of stars have a different abundance of helium. We find that while the red stars have a normal helium abundance, the bluer stars must be enriched in helium by more than 50% with respect to the other population!" These stars are thus the most helium-rich stars ever found, and not by just a few percent! It took some 8 billion years for the Milky Way Galaxy to increase its helium abundance from