WorldWideScience

Sample records for satellites clams experiment

  1. Chemical Characterization of the Aerosol During the CLAMS Experiment Using Aircraft and Ground Stations

    Science.gov (United States)

    Castanho, A. D.; Martins, J.; Artaxo, P.; Hobbs, P. V.; Remer, L.; Yamasoe, M.; Fattori, A.

    2002-05-01

    During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment Nuclepore filters were collected in two ground stations and aboard the University of Wasghington's Convair 580 Reserarch Aircraft. The two ground stations were chosen in strategic positions to characterize the chemical composition, the mass concentration, black carbon (BC) content, and the absorption properties of the aerosol particles at the surface level. One of the stations was located at the Cheasapeake lighthouse (25 km from the coast) and the other one was located at the Wallops Island. Aerosol particles where collected in two stages, fine (d2.5um) and coarse mode (2.5experiment. Airborne samples were also collected on the UW Convair 580 Aircraft. The aircraft samples where used to characterize the elemental composition, mass concentration, BC content, and absorption properties of the aerosol in the atmospheric column in the CLAMS Experiment area. Some of the filters were also submitted to Scanning Electron Microscopy analysis. The particulate matter mass for all the samples were obtained gravimetrically. The concentration of black carbon in the fine filters was optically determined by a broadband reflectance technique. The spectral (from UV to near IR) reflectance in the fine and coarse mode filter were also obtained with a FieldSpec ASD spectrometer. Aerosol elemental characterization (Na through Pb) was obtained by the PIXE (Particle induced X ray emission) analyses of the nuclepore filters. The sources of the aerosol measured at the ground stations were estimated by principal component analyses mainly in the Wallops Island, where a longer time series was collected. One of the main urban components identified in the aerosol during the experiment was sulfate. Black carbon

  2. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  3. CHINA LAUNCHES 2 SCIENTIFIC EXPERIMENT SATELLITES

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China placed 2 scientific experiment satellites into preset orbits atop a LM-4B launch vehicle on Sept. 9, 2004. A LM-4B blasted off at 7:14 am from Taiyuan Satellite Launch Center in Shanxi Province. Sources from the Xi'an Satellite Monitor and Control Center said that one satellite,

  4. Design of satellite flexibility experiments

    Science.gov (United States)

    Kaplan, M. H.; Hillard, S. E.

    1977-01-01

    A preliminary study has been completed to begin development of a flight experiment to measure spacecraft control/flexible structure interaction. The work reported consists of two phases: identification of appropriate structural parameters which can be associated with flexibility phenomena, and suggestions for the development of an experiment for a satellite configuration typical of near-future vehicles which are sensitive to such effects. Recommendations are made with respect to the type of data to be collected and instrumentation associated with these data. The approach consists of developing the equations of motion for a vehicle possessing a flexible solar array, then linearizing about some nominal motion of the craft. A set of solutions are assumed for array deflection using a continuous normal mode method and important parameters are exposed. Inflight and ground based measurements are distinguished. Interrelationships between these parameters, measurement techniques, and input requirements are discussed which assure minimization of special vehicle maneuvers and optimization of data to be obtained during the normal flight sequence.

  5. Advanced ISDN satellite designs and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The research performed by GTE Government Systems and the University of Colorado in support of the NASA Satellite Communications Applications Research (SCAR) Program is summarized. Two levels of research were undertaken. The first dealt with providing interim services Integrated Services Digital Network (ISDN) satellite (ISIS) capabilities that accented basic rate ISDN with a ground control similar to that of the Advanced Communications Technology Satellite (ACTS). The ISIS Network Model development represents satellite systems like the ACTS orbiting switch. The ultimate aim is to move these ACTS ground control functions on-board the next generation of ISDN communications satellite to provide full-service ISDN satellite (FSIS) capabilities. The technical and operational parameters for the advanced ISDN communications satellite design are obtainable from the simulation of ISIS and FSIS engineering software models of the major subsystems of the ISDN communications satellite architecture. Discrete event simulation experiments would generate data for analysis against NASA SCAR performance measure and the data obtained from the ISDN satellite terminal adapter hardware (ISTA) experiments, also developed in the program. The Basic and Option 1 phases of the program are also described and include the following: literature search, traffic mode, network model, scenario specifications, performance measures definitions, hardware experiment design, hardware experiment development, simulator design, and simulator development.

  6. Interim Service ISDN Satellite (ISIS) hardware experiment development for advanced ISDN satellite designs and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

  7. Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

  8. Laser Communication Experiments with Artemis Satellite

    Science.gov (United States)

    Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

    2013-10-01

    In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and

  9. A direct broadcast satellite-audio experiment

    Science.gov (United States)

    Vaisnys, Arvydas; Abbe, Brian; Motamedi, Masoud

    1992-03-01

    System studies have been carried out over the past three years at the Jet Propulsion Laboratory (JPL) on digital audio broadcasting (DAB) via satellite. The thrust of the work to date has been on designing power and bandwidth efficient systems capable of providing reliable service to fixed, mobile, and portable radios. It is very difficult to predict performance in an environment which produces random periods of signal blockage, such as encountered in mobile reception where a vehicle can quickly move from one type of terrain to another. For this reason, some signal blockage mitigation techniques were built into an experimental DAB system and a satellite experiment was conducted to obtain both qualitative and quantitative measures of performance in a range of reception environments. This paper presents results from the experiment and some conclusions on the effectiveness of these blockage mitigation techniques.

  10. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    Science.gov (United States)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  11. Plan of advanced satellite communication experiments using ETS-6

    Science.gov (United States)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  12. Satellite power system (SPS) public outreach experiment

    Energy Technology Data Exchange (ETDEWEB)

    McNeal, S.R.

    1980-12-01

    To improve the results of the Satellite Power System (SPS) Concept Development and Evaluation Program, an outreach experiment was conducted. Three public interest groups participated: the L-5 Society (L-5), Citizen's Energy Project (CEP), and the Forum for the Advancement of Students in Science and Technology (FASST). Each group disseminated summary information about SPS to approximately 3000 constituents with a request for feedback on the SPS concept. The objectives of the outreach were to (1) determine the areas of major concern relative to the SPS concept, and (2) gain experience with an outreach process for use in future public involvement. Due to the combined efforts of all three groups, 9200 individuals/organizations received information about the SPS concept. Over 1500 receipients of this information provided feedback. The response to the outreach effort was positive for all three groups, suggesting that the effort extended by the SPS Project Division to encourage an information exchange with the public was well received. The general response to the SPS differed with each group. The L-5 position is very much in favor of SPS; CEP is very much opposed and FASST is relatively neutral. The responses are analyzed, and from the responses some questions and answers about the satellite power system are presented in the appendix. (WHK)

  13. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  14. Simulator design for advanced ISDN satellite design and experiments

    Science.gov (United States)

    Pepin, Gerald R.

    1992-01-01

    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  15. Satellite broadcasting - The European experience and perspective

    Science.gov (United States)

    Watson, Alan

    1991-11-01

    The use of satellites is considered as a means for developing a European transnational broadcasting system with attention given to the control of technology. A tension is described between maintaining technology as the property of one nation when the DBSs are developed for multinational program broadcasting. The simultaneous development of satellite systems is theorized to lead eventually to a single merged program for a particular nation, and the effect is considered of the regulation of cross-holding and cross-selling systems by investors.

  16. Plan of advanced satellite communications experiment using ETS-VI

    Science.gov (United States)

    Shiomi, Tadashi

    1988-01-01

    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  17. Laser experiments in light cloudiness with the geostationary satellite ARTEMIS

    Science.gov (United States)

    Kuzkov, V.; Kuzkov, S.; Sodnik, Z.

    2016-08-01

    The geostationary satellite ARTEMIS was launched in July 2001. The satellite is equipped with a laser communication terminal, which was used for the world's first inter-satellite laser communication link between ARTEMIS and the low earth orbit satellite SPOT-4. Ground-to-space laser communication experiments were also conducted under various atmospheric conditions involving ESA's optical ground station. With a rapidly increasing volume of information transferred by geostationary satellites, there is a rising demand for high-speed data links between ground stations and satellites. For ground-to-space laser communications there are a number of important design parameters that need to be addressed, among them, the influence of atmospheric turbulence in different atmospheric conditions and link geometries. The Main Astronomical Observatory of NAS of Ukraine developed a precise computer tracking system for its 0.7 m AZT-2 telescope and a compact laser communication package LACES (Laser Atmosphere and Communication experiments with Satellites) for laser communication experiments with geostationary satellites. The specially developed software allows computerized tracking of the satellites using their orbital data. A number of laser experiments between MAO and ARTEMIS were conducted in partial cloudiness with some amount of laser light observed through clouds. Such conditions caused high break-up (splitting) of images from the laser beacon of ARTEMIS. One possible explanation is Raman scattering of photons on molecules of a water vapor in the atmosphere. Raman scattering causes a shift in a wavelength of the photons.In addition, a different value for the refraction index appears in the direction of the meridian for the wavelength-shifted photons. This is similar to the anomalous atmospheric refraction that appears at low angular altitudes above the horizon. We have also estimated the atmospheric attenuation and the influence of atmospheric turbulence on observed results

  18. US experiments flown on the Soviet satellite COSMOS 936

    Science.gov (United States)

    Rosenzweig, S. N.; Souza, K. A.

    1978-01-01

    Results of spaceborne experiments onboard the Cosmos 936 satellite are reported. Alterations in normal bone chemistry, muscle structure, and general physiology resulting from spaceflight are covered along with measurements of cosmic radiation and its potential hazard to man during prolonged spaceflights. Postflight activities involving the seven U.S. experiments are emphasized.

  19. Achievements of Space Scientific Experiments Aboard SJ-8 Satellite

    Institute of Scientific and Technical Information of China (English)

    XIE Jingchang; WAN Shixin; ZHANG Pu; LIN Hai; LIU Fang; HU Wenrui

    2008-01-01

    As scientific experiment payloads, microgravity experiments of fluid physics, life science,combustion science, physics and accelerator measurement were conducted on board the Chinese recoverable satellite SJ-8 during 18-day orbital flight. The experimental payloads and an experiment support system constituted the microgravity experiment system of the flight mission. This article has presented the briefs of the scientific achievements of these space experiments, the composition and performance of the Microgravity Experimental System (MES) and the general picture of the overall flight mission, respectively.

  20. A digitally implemented communications experiment utilizing the Hermes /CTS/ satellite

    Science.gov (United States)

    Jackson, H. D.; Fiala, J.

    1977-01-01

    Attention is given to an investigation being conducted by NASA-Lewis and Comsat Laboratories which uses the Hermes (CTS) satellite to explain digital link implementation and the advantages it provides over conventional analog systems. The experiment concentrates on developing several video, audio, and data digital communications techniques.

  1. A digitally implemented communications experiment utilizing the Hermes (CTS) satellite

    Science.gov (United States)

    Jackson, H. D.; Fiala, J. L.

    1977-01-01

    The Hermes (CTS) experiment program made possible a significant effort directed toward new developments which will reduce the costs associated with the distribution of satellite services. Advanced satellite transponder technology and small inexpensive earth terminals were demonstrated as part of the Hermes program. Another system element that holds promise for reduced transmission cost is associated with the communication link implementation. An experiment is described which uses CTS to demonstrate digital link implementation and its advantages over conventional analog systems. A Digitally Implemented Communications experiment which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice and high-bit-rate data is also described. Presentation of the experiment concept which concentrates on the evaluation of full-duplex digital television in the teleconferencing environment is followed by a description of unique equipment that was developed.

  2. Remote Synchronization Experiments for Quasi-Senith Satellite System Using Current Geostationary Satellites

    Directory of Open Access Journals (Sweden)

    Toshiaki Iwata

    2010-01-01

    Full Text Available The remote synchronization system for the onboard crystal oscillator (RESSOX realizes accurate synchronization between an atomic clock at a ground station and the QZSS onboard crystal oscillator, reduces overall cost and satellite power consumption, as well as onboard weight and volume, and is expected to have a longer lifetime than a system with onboard atomic clocks. Since a QZSS does not yet exist, we have been conducting synchronization experiments using geostationary earth orbit satellites (JCSAT-1B or Intelsat-4 to confirm that RESSOX is an excellent system for timing synchronization. JCSAT-1B, the elevation angle of which is 46.5 degrees at our institute, is little affected by tropospheric delay, whereas Intelsat-4, the elevation angle of which is 7.9 degrees, is significantly affected. The experimental setup and the results of uplink experiments and feedback experiments using mainly Intelsat-4 are presented. The results show that synchronization within 10 ns is realized.

  3. Satellite broadcasting experiments and in-orbit performance of BSE

    Science.gov (United States)

    Shimoseko, S.; Yamamoto, M.; Kajikawa, M.; Arai, K.

    1981-09-01

    The Japanese medium-scale Broadcasting Satellite for Experimental Purposes (BSE) was launched in April 1978 and placed in a geostationary orbit at 110 deg E longitude. Two transmitters with bandwidths of 50 MHz and 80 MHz were mounted on the BSE transponder to conduct experiments on various television signals; no significant variation in transmission characteristics was observed during the two-year period. Rain attenuation characteristics in the 12 GHz band were studied and a value of 6.6 dB was registered in Owase, one of the most rainy areas in Japan. The strength of the rain scatter wave of the BSE uplink signal was measured to investigate the characteristics between broadcasting satellite uplink and a terrestrial link in the 14 GHz band. Uplink power control, important for the efficient operation of satellite communications systems, was shown to compensate the variations in receiving power due to fluctuations in the beam pointing of the satellite antenna. Routine operations were performed to check the three-axis attitude control, stationkeeping, housekeeping, and the bus equipment. The electrical power, secondary propulsion, thermal control, and communication subsystems were also evaluated. The first operations 1 broadcasting satellite is scheduled to be launched early in 1984.

  4. Small satellite attitude determination during plasma brake deorbiting experiment

    Science.gov (United States)

    Khurshid, Osama; Selkäinaho, Jorma; Soken, Halil Ersin; Kallio, Esa; Visala, Arto

    2016-12-01

    This paper presents a study on attitude estimation during the Plasma Brake Experiment (PBE) onboard a small satellite. The PBE demands that the satellite be spun at a very high angular velocity, up to 200 deg/s, to deploy the tether using centrifugal force. The spin controller, based on purely magnetic actuation, and the PBE demands accurate attitude estimation for the successful execution of the experiment. The biases are important to be estimated onboard small satellites due to the closely integrated systems and relatively higher interference experienced by the sensors. However, bias estimation is even more important for PBE due to the presence of a high voltage unit, onboard the satellite, that is used to charge the tether and can be the source of interference. The attitude and the biases, when estimated simultaneously, results in an augmented state vector that poses a challenge to the proper tuning of process noise. The adaptation of process noise covariance has, therefore, been studied and analysed for the challenging PBE. It has been observed that adapting the process noise covariance improves the estimation accuracy during the spin-up phase. Therefore, it is very important to use adaptive process noise covariance estimation.

  5. Laser Experiments with ARTEMIS Satellite in Cloudy Conditions

    Science.gov (United States)

    Kuzkov, Volodymyr; Sodnik, Zoran; Kuzkov, Sergii; Caramia, Vincenzo

    2014-05-01

    In July 2001, the ARTEMIS satellite with laser communication terminal OPALE on board was launched. 1789 laser communications sessions were performed between ARTEMIS and SPOT-4 (PASTEL) from 01 April 2003 to 09 January 2008 with total duration of 378 hours. In addition ESA's Optical Ground Station (OGS) performed laser communication experiments with OPALE in various atmospheric conditions. Since the launch of ARTEMIS, the amount of information handled by geostationary telecommunication satellites has increased dramatically and so has the demand for data rate that needs to be transmitted from ground. With limited bandwidth allocations in the radio frequency bands interest has grown for laser communication feeder link technology. In this respect there is interest to compare the influence of atmosphere conditions in different atmospheric regions with respect to laser transmission. Two locations are being compared, namely ESA's OGS (located in an altitude of 2400 m above sea level) and the Main Astronomical Observatory of Ukraine (MAO) (located at an altitude of 190 m above sea level). In 2002 MAO started the development of a ground laser communication system for the AZT-2 telescope. The MAO developed compact laser communication system is called LACES (Laser Atmosphere and Communication Experiments with Satellites) [1] and the work was supported by the National Space Agency of Ukraine and by ESA. The beacon laser from OPALE was occasionally detected even in cloudy conditions and an anomalous atmospheric refraction at low elevation angles was observed. The main results of laser experiments with ARTEMIS through clouds are presented in the paper.

  6. Optimal scan strategies for future CMB satellite experiments

    CERN Document Server

    Wallis, Christopher G R; Battye, Richard A; Delabrouille, Jacques

    2016-01-01

    The B-mode polarisation power spectrum in the Cosmic Microwave Background (CMB) is about four orders of magnitude fainter than the CMB temperature power spectrum. Any instrumental imperfections that couple temperature fluctuations to B-mode polarisation must therefore be carefully controlled and/or removed. We investigate the role that a scan strategy can have in mitigating certain common systematics by averaging systematic errors down with many crossing angles. We present approximate analytic forms for the error on the recovered B-mode power spectrum that would result from differential gain, differential pointing and differential ellipticity for the case where two detector pairs are used in a polarisation experiment. We use these analytic predictions to search the parameter space of common satellite scan strategies in order to identify those features of a scan strategy that have most impact in mitigating systematic effects. As an example we go on to identify a scan strategy suitable for the CMB satellite pro...

  7. Satellite hole formation during dewetting: experiment and simulation

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    The dewetting of thin polymer films on solid substrates has been studied extensively in recent years. These films can decay either by nucleation events or by spinodal dewetting, essentially only depending on the interface potential describing the short- and long-range intermolecular interactions between the interfaces and the initial film thickness. Here, we describe experiments and simulations concerned with the decay of polystyrene thin films. The rupture of the film occurs by the formation of a correlated pattern of holes ('satellite holes') along the liquid rims accumulating at the channel borders. The development of this complex film rupture process, which is neither simply spinodal nor nucleation dewetting, can be mimicked precisely by making use of a novel simulation code based on a rigorous mathematical treatment of the thin film equation and on the knowledge of the effective interface potential of the system. The conditions that determine the appearance and the position of the satellite holes around ...

  8. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    Science.gov (United States)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  9. Snow, Ice, & Satellites: An Early Career Researcher's Experience with Twitter

    Science.gov (United States)

    Pope, A.; Scambos, T. A.

    2014-12-01

    As a doctoral student, I was lucky enough to be able to experiment with a variety of communication and outreach activities (classroom visits, museum events, science festivals, blogging, social media, etc.) to build communication skills and learn how to talk about my science without writing a journal article. More importantly, the wide range of experience helped me identify what worked for me. My favorite way to share my science now? Twitter. To many, Twitter is a frivolous platform for sharing snippets 140 characters or less. To me, however, it is how I can connect directly with the elusive "wider public" and share my science. Specifically, I use satellite imagery (mostly Landsat 8) to study glaciers around the world. I look at long-term change related to climate, and I also investigate new, innovative ways to use satellite imagery to better understand glaciers and ice sheets. Luckily for me, my research is very visual. Whether fieldwork snapshots or satellite data, images make for great, shareable, accessible tweets. In this presentation, I propose to share my experience of tweeting as an early career researcher. I will include successful strategies (e.g. particular #hashtags, creating new content, using story-telling, timely tweets), as well as some not-so-successful attempts. I will also talk about how I built my Twitter network. In addition to anecdotes, I will include evaluation of my Twitter activity using available metrics and analytics (e.g. followers, favorites, re-tweets, Klout score, etc.). While misunderstood by many in the scientific community, Twitter is a platform increasingly being adopted by researchers. Used correctly, it can be a great tool for connecting directly with an interested, non-technical audience eager to learn about your research. With my experiences and evaluation, I will show how both scientists and the networks that they join and create can benefit by using Twitter as a platform for science communication.

  10. Correlation between perkinsosis and growth in clams Ruditapes spp.

    Science.gov (United States)

    Dang, Cécile; de Montaudouin, Xavier; Binias, Cindy; Salvo, Flora; Caill-Milly, Nathalie; Bald, Juan; Soudant, Philippe

    2013-11-06

    Perkinsosis is one of the most widespread diseases affecting commercially important species of molluscs globally. We examined the impact of Perkinsus spp. on shell growth at the individual scale in 2 clam species: Ruditapes decussatus from Mundaka Estuary (Spain) and R. philippinarum from Arcachon Bay (France). At Arcachon, 2 contrasting sites in terms of environment and Perkinsus olseni presence were chosen: Arguin (disease-free) and Ile aux Oiseaux (infected site). We monitored the dynamics of perkinsosis over the course of the experiment at Mundaka and Ile aux Oiseaux. Prevalences were high (>70%), and intensities were around 105 cells g-1 wet gills at Ile aux Oiseaux, and 106 cells g-1 at Mundaka. No significant differences in prevalence or intensity were observed over time. A 2 yr field growth experiment of tagged-recaptured clams was performed to determine individual clam growth rate, condition index (CI), and Perkinsus spp. infection intensity. Clams were collected at Ile aux Oiseaux and transplanted to Arguin. The growth rate was always significantly and negatively correlated with Perkinsus spp. infection, and positively correlated with CI. CI and Perkinsus spp. infection explained 19% and 7% of the variability of the growth rate at Mundaka and Ile aux Oiseaux, respectively. In experimental clams at Arguin, P. olseni infection explained 26% of the variability of the growth rate at the lower tidal level. Our results suggest that at a concentration of between 105 and 106 cells g-1, perkinsosis affects the physiological functions of the clams, highlighted by its impact on the growth rate.

  11. Laboratory experiment, the number of clams consumed by the fish of FLORIDA POMPANO in experimental tanks feeding on coquina clams individually and in groups from 2013-11-26 to 2013-12-03 (NCEI Accession 0127553)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset includes the results from a laboratory experiment assessing whether juvenile Florida Pompano (Trachinotus carolinus) foraging success is greater when in...

  12. COMSTAR satellite 19/29 GHz propagation experiment

    Science.gov (United States)

    Bloch, S. C.; Davidson, D.; Tang, D. D.

    1981-08-01

    Results and analysis are presented for the 19/29-GHz satellite propagation experiments using beacons aboard the COMSTAR series. Emphasis is on diversity performance of the Tampa, Florida, Triad and single-site attenuation distributions in intense rain, and on single-site performance at Waltham, Massachusetts. The substantial data base evolved to show a flattish tail on distributions due to rapid rate-of-change at onset and recovery; this type of distribution found in Tampa rain environment was not found in Waltham.

  13. A review of satellite communication and propagation experiments for frequencies above 10 GHz

    Science.gov (United States)

    Setty, P. N. R.; Goessl, H.; Hounam, D.

    1983-02-01

    Satellite experiments aimed at improving communications in the higher frequency bands, especially above 10 GHz, are described. The basic types of transmission and measurement methods in these experiments are discussed, including beacon transmission, transmission from the ground with measurement on the ground.The satellite experiments considered include: ATS-5 millimeter wave propagation experiments; ATS-6 experiments at 13, 18, 20 and 30 GHz; Comstar experiments at 19 and 28 GHz; experiments with the CTS, ETS-II, SIRIO, CS, BSE, and OTS satellites. The payload parameters of the satellites are shown, and functional block diagrams for the ground terminals are presented.

  14. Human sapovirus in clams, Japan.

    Science.gov (United States)

    Hansman, Grant S; Oka, Tomoichiro; Okamoto, Reiko; Nishida, Tomoko; Toda, Schoichi; Noda, Mamoru; Sano, Daisuke; Ueki, You; Imai, Takahiro; Omura, Tatsuo; Nishio, Osamu; Kimura, Hirokazu; Takeda, Naokazu

    2007-04-01

    Human sapovirus was detected in 4 of 57 clam packages by reverse transcription-PCR and sequence analysis. This represents the first finding of sapovirus contamination in food. Closely matching sequences have been detected in stool specimens from patients with gastroenteritis in Japan, which indicates a possible food-to-human transmission link.

  15. Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

  16. Satellite hole formation during dewetting: experiment and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Neto, Chiara [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Jacobs, Karin [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Seemann, Ralf [Department of Applied Physics, University of Ulm, Albert Einstein Allee 11, D-89069 Ulm (Germany); Blossey, Ralf [Centre for Bioinformatics, Saarland University, PO Box 151150, D-66041 Saarbruecken (Germany); Becker, Juergen [Institute of Applied Mathematics, University of Bonn, Beringstrasse 6, D-53115 Bonn (Germany); Gruen, Guenther [Institute of Applied Mathematics, University of Bonn, Beringstrasse 6, D-53115 Bonn (Germany)

    2003-05-21

    The dewetting of thin polymer films on solid substrates has been studied extensively in recent years. These films can decay either by nucleation events or by spinodal dewetting, essentially only depending on the interface potential describing the short- and long-range intermolecular interactions between the interfaces and the initial film thickness. Here, we describe experiments and simulations concerned with the decay of polystyrene thin films. The rupture of the film occurs by the formation of a correlated pattern of holes ('satellite holes') along the liquid rims accumulating at the channel borders. The development of this complex film rupture process, which is neither simply spinodal nor nucleation dewetting, can be mimicked precisely by making use of a novel simulation code based on a rigorous mathematical treatment of the thin film equation and on the knowledge of the effective interface potential of the system. The conditions that determine the appearance and the position of the satellite holes around pre-existing holes are discussed.

  17. Optimal scan strategies for future CMB satellite experiments

    Science.gov (United States)

    Wallis, Christopher G. R.; Brown, Michael L.; Battye, Richard A.; Delabrouille, Jacques

    2017-04-01

    The B-mode polarization power spectrum in the cosmic microwave background (CMB) is about four orders of magnitude fainter than the CMB temperature power spectrum. Any instrumental imperfections that couple temperature fluctuations to B-mode polarization must therefore be carefully controlled and/or removed. We investigate the role that a scan strategy can have in mitigating certain common systematics by averaging systematic errors down with many crossing angles. We present approximate analytic forms for the error on the recovered B-mode power spectrum that would result from differential gain, differential pointing and differential ellipticity for the case where two detector pairs are used in a polarization experiment. We use these analytic predictions to search the parameter space of common satellite scan strategies in order to identify those features of a scan strategy that have most impact in mitigating systematic effects. As an example, we go on to identify a scan strategy suitable for the CMB satellite proposed for the European Space Agency M5 call, considering the practical considerations of fuel requirement, data rate and the relative orientation of the telescope to the earth. Having chosen a scan strategy we then go on to investigate the suitability of the scan strategy.

  18. PEACESAT (Pan Pacific Education and Communication Experiments by Satellite) Project Early Experience: The Design and Early Years of the First Educational Communication Satellite Experiment. Report 1.

    Science.gov (United States)

    Hawaii Univ., Honolulu.

    The PEACESAT Project (Pan Pacific Education and Communication Experiments by Satellite) has been in daily operation for four years since April 1971. Initiated as an individual research project of a university faculty member, it has expanded to involve educational institutions in 12 countries or jurisdictions in the Pacific Basin. These…

  19. Target organs of the Manila clam Ruditapes philippinarum for studying metal accumulation and biomarkers in pollution monitoring: laboratory and in-situ transplantation experiments.

    Science.gov (United States)

    Won, Eun-Ji; Kim, Kyung-Tae; Choi, Jin-Young; Kim, Eun-Soo; Ra, Kongtae

    2016-08-01

    To characterize the target organs of the Manila clam Ruditapes philippinarum for use in environmental study, the accumulation of trace metals and three biomarkers was measured in different organs. Exposure with Cu and Pb carried out under laboratory conditions revealed a linear uptake of metals throughout the experimental period in each tissue. In particular, significant increase was observed in gills and mantle. The increase of intracellular reactive oxygen species showed the great potential of gills as a target tissue for both Cu and Pb exposure. The highest activity of glutathione S-transferase and their relative increase in activity were also observed in gills. Metallothionein-like protein levels, however, increased greatly in the digestive gland and mantle during Cu and Pb exposure, respectively, although all tissues, except the foot, showed significant changes after 24 h of metal exposure. In the field study, the highest concentration of metals was recorded in the gills and mantle, accounting for over 50 % of the total accumulated metal in all sites. Additionally, Cu and Pb increased significantly in these two organs, respectively. However, the order of accumulation rate in laboratory exposure was not concomitant with those of the lab-based study, suggesting that different routes of metal uptake and exposure duration induce distinct partitioning of metals and regulating system in R. philippinarum. These series of exposure studies demonstrated that gills, mantle, and digestive gland in R. philippinarum are potential target tissues in environmental monitoring study using metal concentrations and biomarkers.

  20. CTS United States experiments - A progress report. [Communications Technology Satellite for high power broadcasting

    Science.gov (United States)

    Robbins, W. H.; Donoughe, P. L.

    1976-01-01

    The Communications Technology Satellite (CTS) is a high-power broadcast satellite launched by NASA on January 17, 1976. CTS is the first satellite to operate at a frequency of 12 gigahertz and incorporates technology making possible new satellite telecommunications services. CTS is a cooperative program of the United States and Canada. This paper presents the results of the United States experimental activity to date. Wide segments of the population are involved in the Experiments Program, including the scientific community, other government agencies, industry, and the education and health entities. The experiments are associated with both technological objectives and the demonstration of new community and social services via satellite.

  1. Experience and Methodology gained from 4 years of Student Satellite Projects

    DEFF Research Database (Denmark)

    Alminde, Lars; Bisgaard, Morten; Bhanderi, Dan

    2005-01-01

    The AAU Cubesat student satellite project at Aalborg University was initiated in September 2001 and led to the launch of the satellite on the 30th of June 2003 with a “Rockot” rocket from Plesetsk in Russia. The satellite survived three months in orbit and based on the experiences gained the next...... student satellite project was commenced called AAUSAT II which is due for launch early 2006. This paper presents the experiences gained and lessons learned from the work with student satellite projects at Aalborg University as well as the methodology used to manage these projects. First an introduction...... to the concept of student satellite projects is given and the two student satellite projects are introduced. Then an introduction and description of the Problem Based Learning concept used at Aalborg University is given and advantages of applying it to these projects are discussed. The benets of student...

  2. Integrated Cryogenic Satellite Communications Cross-Link Receiver Experiment

    Science.gov (United States)

    Romanofsky, R. R.; Bhasin, K. B.; Downey, A. N.; Jackson, C. J.; Silver, A. H.; Javadi, H. H. S.

    1995-01-01

    An experiment has been devised which will validate, in space, a miniature, high-performance receiver. The receiver blends three complementary technologies; high temperature superconductivity (HTS), pseudomorphic high electron mobility transistor (PHEMT) monolithic microwave integrated circuits (MMIC), and a miniature pulse tube cryogenic cooler. Specifically, an HTS band pass filter, InP MMIC low noise amplifier, HTS-sapphire resonator stabilized local oscillator (LO), and a miniature pulse tube cooler will be integrated into a complete 20 GHz receiver downconverter. This cooled downconverter will be interfaced with customized signal processing electronics and integrated onto the space shuttle's 'HitchHiker' carrier. A pseudorandom data sequence will be transmitted to the receiver, which is in low Earth orbit (LEO), via the Advanced Communication Technology Satellite (ACTS) on a 20 GHz carrier. The modulation format is QPSK and the data rate is 2.048 Mbps. The bit error rate (BER) will be measured in situ. The receiver is also equipped with a radiometer mode so that experiment success is not totally contingent upon the BER measurement. In this mode, the receiver uses the Earth and deep space as a hot and cold calibration source, respectively. The experiment closely simulates an actual cross-link scenario. Since the receiver performance depends on channel conditions, its true characteristics would be masked in a terrestrial measurement by atmospheric absorption and background radiation. Furthermore, the receiver's performance depends on its physical temperature, which is a sensitive function of platform environment, thermal design, and cryocooler performance. This empirical data is important for building confidence in the technology.

  3. Geostationary Operational Environmental Satellite (GOES)-8 mission flight experience

    Science.gov (United States)

    Noonan, C. H.; McIntosh, R. J.; Rowe, J. N.; Defazio, R. L.; Galal, K. F.

    1995-05-01

    The Geostationary Operational Environmental Satellite (GOES)-8 spacecraft was launched on April 13, 1994, at 06:04:02 coordinated universal time (UTC), with separation from the Atlas-Centaur launch vehicle occurring at 06:33:05 UTC. The launch was followed by a series of complex, intense operations to maneuver the spacecraft into its geosynchronous mission orbit. The Flight Dynamics Facility (FDF) of the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) was responsible for GOES-8 attitude, orbit maneuver, orbit determination, and station acquisition support during the ascent phase. This paper summarizes the efforts of the FDF support teams and highlights some of the unique challenges the launch team faced during critical GOES-8 mission support. FDF operations experience discussed includes: (1) The abort of apogee maneuver firing-1 (AMF-1), cancellation of AMF-3, and the subsequent replans of the maneuver profile; (2) The unexpectedly large temperature dependence of the digital integrating rate assembly (DIRA) and its effect on GOES-8 attitude targeting in support of perigee raising maneuvers; (3) The significant effect of attitude control thrusting on GOES-8 orbit determination solutions; (4) Adjustment of the trim tab to minimize torque due to solar radiation pressure; and (5) Postlaunch analysis performed to estimate the GOES-8 separation attitude. The paper also discusses some key FDF GOES-8 lessons learned to be considered for the GOES-J launch which is currently scheduled for May 19, 1995.

  4. Spread spectrum mobile communication experiment using ETS-V satellite

    Science.gov (United States)

    Ikegami, Tetsushi; Suzuki, Ryutaro; Kadowaki, Naoto; Taira, Shinichi; Sato, Nobuyasu

    1990-01-01

    The spread spectrum technique is attractive for application to mobile satellite communications, because of its random access capability, immunity to inter-system interference, and robustness to overloading. A novel direct sequence spread spectrum communication equipment is developed for land mobile satellite applications. The equipment is developed based on a matched filter technique to improve the initial acquisition performance. The data rate is 2.4 kilobits per sec. and the PN clock rate is 2.4552 mega-Hz. This equipment also has a function of measuring the multipath delay profile of land mobile satellite channel, making use of a correlation property of a PN code. This paper gives an outline of the equipment and the field test results with ETS-V satellite.

  5. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    OpenAIRE

    Wu Xiao-po; Zhao Hai-yang; Xi Song-tao

    2014-01-01

    Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  6. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    Directory of Open Access Journals (Sweden)

    Wu Xiao-po

    2014-06-01

    Full Text Available Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  7. Toxicity of atrazine to the juvenile hard clam, Mercenaria mercenaria.

    Science.gov (United States)

    Lawton, Jennifer C; Pennington, Paul L; Chung, Katy W; Scott, Geoffrey I

    2006-11-01

    The herbicide atrazine is one of the most heavily used pesticides in the United States. The effects of atrazine on the clam Mercenaria mercenaria were evaluated in aqueous and sediment laboratory assays. Juvenile clams of approximately 1mm in size were used for all experiments. An acute aqueous bio-assay was used to determine the 96-h LC(50) for the juvenile clams. A chronic aqueous bioassay was conducted at lower atrazine concentrations over a 10-day exposure period to examine both lethal and sublethal (dry mass, shell size, and condition index) endpoints. A chronic sediment bioassay examined mortality and sublethal endpoints in a 10-day exposure. The acute 96-h LC(50) was 5608 microg/L with 95% confidence intervals ranging from 5003 to 6287 microg/L. Results of the chronic aqueous assay indicated both lethal and sublethal (reduced shell size) effects at high atrazine concentrations. In the 10-day chronic aqueous assay, the no observable effect concentration was 500 microg/L, the lowest observable effect concentration was 1000 microg/L, and the maximum allowable toxicant concentration (MATC) was 707 microg/L. There were no significant effects of atrazine in the chronic sediment exposure. Safe concentrations for the aqueous experiments were estimated by applying an uncertainty factor of 10 to the calculated MATC values. While there were adverse effects of atrazine at high concentrations, these results suggest that atrazine is not directly toxic to M. mercenaria at environmentally relevant concentrations.

  8. Satellite delivered cable television - A Warner-Amex experience

    Science.gov (United States)

    Stasi, D.; Setos, A.

    1984-03-01

    Operational aspects of the ground reception of C-band satellite transmissions by CATV operators are discussed. The current C-band network with 20 transmitters and 6000 receivers is shown to have been made possible by the relaxation of the earth-station licensing requirements, while economic factors have been responsible for the introduction of sophisticated and less sophisticated techniques to obtain 'adequate' picture quality with smaller antennas located in more difficult reception sites. The adoption of a quality standard of -18 dB C/I on the basis of empirical tests of viewer perception is considered reasonable, but further lowering of the standard (beyond -15 dB) is questioned. It is pointed out that antenna systems providing only minimal reception with 4-deg satellite spacing may be rendered useless by satellite video-traffic interference when 2-deg spacing is introduced over the next two years.

  9. Design and implementation of an experiment scheduling system for the ACTS satellite

    Science.gov (United States)

    Ringer, Mark J.

    1994-01-01

    The Advanced Communication Technology Satellite (ACTS) was launched on the 12th of September 1993 aboard STS-51. All events since that time have proceeded as planned with user operations commencing on December 6th, 1993. ACTS is a geosynchronous satellite designed to extend the state of the art in communication satellite design and is available to experimenters on a 'time/bandwidth available' basis. The ACTS satellite requires the advance scheduling of experimental activities based upon a complex set of resource, state, and activity constraints in order to ensure smooth operations. This paper describes the software system developed to schedule experiments for ACTS.

  10. Applications Technology Satellite ATS-6 experiment checkout and continuing spacecraft evaluation report

    Science.gov (United States)

    Moore, W.; Prensky, W. (Editor)

    1974-01-01

    The activities of the ATS-6 spacecraft are reviewed. The following subsystems and experiments are summarized: (1) radio beacon experiments; (2) spacecraft attitude precision pointing and slewing adaptive control experiment; (3) satellite instruction television experiment; (4) thermal control subsystem; (5) spacecraft propulsion subsystem; (6) telemetry and control subsystem; (7) millimeter wave experiment; and (8) communications subsystem. The results of performance evaluation of its subsystems and experiments are presented.

  11. CTS /Hermes/ - United States experiments and operations summary. [Communications Technology Satellite

    Science.gov (United States)

    Donoughe, P. L.; Hunczak, H. R.

    1977-01-01

    The U.S. experiments conducted with the Communications Technology Satellite, a joint Canadian-U.S. venture launched in 1976, are discussed. The 14/12 GHz frequencies employed by the 200-W transmitter on board the satellite provide two-way television and voice communications. Applications of the satellite in the categories of health care, community services and education are considered; experiments have also made use of the special properties of the super-high frequency band (e.g. link characterization and digital communications). Time-sharing of the 14/12 GHz communication between the U.S. and Canada has functioned well.

  12. NASA Perspectives on Earth Observations from Satellite or 50 Years of Meteorological Satellite Experiments-The NASA Perspective

    Science.gov (United States)

    Einaudi, Franco

    2010-01-01

    The NASA was established in 1959. From those very eady days to the present NASA has been intimately involved with NOAA and the scientific community in the development and operation of satellite and sensor experiments. The early efforts included experiments on the TIROS and geostationary Applications Technology Satellites (ATS) series. In the latter case the spin-scan cameras conceived by Verner Suomi, along with the TIROS cameras, opened new vistas at what could be done in meteorological studies with the daily, nearly global, synoptic views from space-borne sensors As the years passed and the Nimbus series of satellites came into being in the 1960's, more quantitative observations with longer-lifetime, increasingly capable, better calibrated instruments came into being. NASA, in collaboration with and in support of NOAA, implemented operational systems that we now know as the Polar Operational Environmental Satellite (POES) series and the Geostationary Operational Environmental Satellite (GOES) series that provided dependable, continuous, dedicated satellite observations for use by the weather and atmospheric science communities. Through the 1970's, 1980's, and 1990's improved, well-calibrated instruments with more spectral bands extending into the thermal and the microwave portions of the electromagnetic spectrum were provided to obtain accurate soundings of the atmosphere, atmospheric chemistry constituents such as ozone, global sea surface temperature, snow and ice extent, vegetation dynamics, etc. In the 1990's and up to the present the NASA/Earth Observing System (EOS) has been developed, implemented, and operated over many years to provide a very comprehensive suite of observations of the atmosphere, as well as land and ocean parameters. The future looks bright wherein the development of new systems, broadly described by the National Academy of Science Decadal Study, is now underway. NASA, along with collaborations with NOAA, other agencies, and the

  13. From laboratory plasma experiments to space plasma experiments with `CubeSat' nano-satellites

    Science.gov (United States)

    Charles, Christine

    2016-09-01

    `CubeSat' nano-satellites provide low-cost access to space. SP3 laboratory's involvement in the European Union `QB50' `CubeSat' project [www.qb50.eu] which will launch into space 50 `CubeSats' from 27 Countries to study the ionosphere and the lower thermosphere will be presented. The Chi Kung laboratory plasma experiment and the Helicon Double Layer Thruster prototype can be tailored to investigate expanding magnetized plasma physics relevant to space physics (solar corona, Earth's aurora, adiabatic expansion and polytropic studies). Chi Kung is also used as a plasma wind tunnel for ground-based calibration of the University College London QB50 Ion Neutral Mass Spectrometer. Space qualification of the three Australian QB50 `CubeSats' (June 2016) is carried out in the WOMBAT XL space simulation chamber. The QB50 satellites have attitude control but altitude control is not a requirement. SP3 is developing end-to-end miniaturised radiofrequency plasma propulsion systems (such as the Pocket Rocket and the MiniHel thrusters with power and propellant sub-systems) for future `CubeSat' missions.

  14. Effect of Surface Preparation on CLAM/CLAM Hot Isostatic Pressing diffusion bonding joints

    Science.gov (United States)

    Li, C.; Huang, Q.; Zhang, P.

    2009-04-01

    Surface preparation is essential for the Hot Isostatic Pressing (HIP) diffusion bonding of RAFM steels. Hot Isostatic Pressing (HIP) diffusion bonding experiments on China Low Activation Martensitic (CLAM) steel was performed to study the effect of surface preparation. A few approaches such as hand lapping, dry-milling and grinding etc., were used to prepare the faying surfaces of the HIP joints. Different sealing techniques were used as well. The HIP parameters were 150 MPa/3 h/1150 °C. After post HIP heat treatment (PHHT), the tensile and Charpy impact tests were carried out. The results showed that hand lapping was not suitable to prepare the faying surfaces of HIP diffusion bonding specimens although the surface roughness by hand lapping was very low.

  15. The experience of land cover change detection by satellite data

    Institute of Scientific and Technical Information of China (English)

    Lev SPIVAK; Irina VITKOVSKAYA; Madina BATYRBAYEVA; Alexey TEREKHOV

    2012-01-01

    Sigificant dependence from climate and anthropogenic influences characterize ecological systems of Kazakhstan.As result of the geographical location of the republic and ecological situation vegetative degradation sites exist throughout the territory of Kazakhstan.The major process of desertification takes place in the arid and semi-arid areas.To allocate spots of stable degradation of vegetation,the transition zone was first identified.Productivity of vegetation in transfer zone is slightly dependent on climate conditions.Multi-year digital maps of vegetation index were generated with NOAA satellite images.According to the result,the territory of the republic was zoned by means of vegetation productivity criterion.All the arable lands in Kazakhstan are in the risky agriculture zone.Estimation of the productivity of agricultural lands is highly important in the context of risky agriculture,where natural factors,such as wind and water erosion,can significantly change land quality in a relatively short time period.We used an integrated vegetation index to indicate land degradation measures to assess the inter-annual features in the response of vegetation to variations in climate conditions from lowresolution satellite data for all of Kazakhstan.This analysis allowed a better understanding of the spatial and temporal variations of land degradation in the country.

  16. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    Science.gov (United States)

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  17. Q-Band (37-41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Science.gov (United States)

    Simmons, Rainee N.; Wintucky, Edwin G.

    2012-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37-41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cut-paraboloidal reflector.

  18. Q-Band (37 to 41 GHz) Satellite Beacon Architecture for RF Propagation Experiments

    Science.gov (United States)

    Simons, Rainee N.; Wintucky, Edwin G.

    2014-01-01

    In this paper, the design of a beacon transmitter that will be flown as a hosted payload on a geostationary satellite to enable propagation experiments at Q-band (37 to 41 GHz) frequencies is presented. The beacon uses a phased locked loop stabilized dielectric resonator oscillator and a solid-state power amplifier to achieve the desired output power. The satellite beacon antenna is configured as an offset-fed cutparaboloidal reflector.

  19. Preliminary Investigation of the Satellite Gravitational Red Shift Experiment

    Science.gov (United States)

    Zacharias, J. R.; Searle, C. L.; Graham, J. W.; Badessa, R. S.; Bates, V. J.; Kent, R. L.

    1961-01-01

    The work performed under this contract involved study, design, and construction of experimental equipment to perform a short-term measurement of the gravitational red shift. In the system designed, phase comparison techniques are employed so that the time interval required to obtain a single measurement for one altitude is of the order of one minute. An elliptical orbit was chosen to permit measurement of frequency shift as a function of altitude. One particularly attractive orbit is that having a 12-hour orbiting period (perigee, 270 miles, apogee 24,800 miles). This orbit, shown in Fig. 1, allows continuous measurements to be made over an 11-hour interval during which time the altitude is varying greatly. Measurements can not be made for the succeeding 14 hours. Since the variation of frequency difference with altitude is of greatest interest, a fixed offset or a slow drift between the oscillator on the ground and. the oscillator in the satellite will not invalidate the measurements.

  20. The Clam Trail: Blending Science Education, Public Art, and Tourism

    Science.gov (United States)

    Muscio, Cara; Flimlin, Gef; Bushnell, Rick

    2011-01-01

    The Barnegat Bay Shellfish Restoration's Clam Trail is an award-winning scavenger hunt that combines science education, public art, and tourism. This family adventure has participants seeking out giant painted fiberglass clams, upweller clam nurseries, and points of interest in search of science facts to record on their forms. Upon returning these…

  1. 33 CFR 117.323 - Outer Clam Bay

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  2. ClamWin Free Antivirus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    ClamWin是在自由软件基金会(Free Software Foundation)支持下的一个杀毒软件开发项目。因此软件使用与传播均是免费的(当然传播要遵从GNL协议了)。杀毒软件的目前版本是0.88,实际上还处于较为初级的阶段,但查杀病毒这一主体功能是值得信赖的。软件没有采用添加到系统服务的自启动方式,这样做的一个好处是系统资源占用率极低,在监视状态下仅开启一个两、三兆大小的进程。软件杀毒时速度较慢,并且没有“加速”选项可设置。

  3. The Combined Release and Radiation Effects Satellite (CRRES) program: A unique series of scientific experiments

    Science.gov (United States)

    Reasoner, David L.; McCook, Morgan W.; Vaughan, William W.

    The Defense Department and NASA have joined in a program to study the space environment which surrounds the earth and the effects of space radiation on modern satellite electronic systems. The Combined Release and Radiation Effects Satellite (CRRES) will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with sub-orbital rocket probes. The chemical releases will 'paint' the magnetic and electric fields of earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments. Some of the topics discussed include the following: the effects of earthspace; the need for active experiments; types of chemical releases; the CRRES program schedule; international support and coordinated studies; photographing chemical releases; information on locating chemical releases for observation by the amateur; and CRRES as a program.

  4. Real-Time Mesoscale Forecast Support During the CLAMS Field Campaign

    Institute of Scientific and Technical Information of China (English)

    WANG Donghai; P. MINNIS; T. P. CHARLOCK; D. K. ZHOU; F. G. ROSE; W. L. SMITH; W. L. SMITH Jr.; L. NGUYEN

    2007-01-01

    This paper reports the use of a specialized, mesoscale, numerical weather prediction (NWP) system and a satellite imaging and prediction system that were set up to support the CLAMS (Chesapeake Lighthouse and Aircraft Measurements for Satellites) field campaign during the summer of 2001. The primary objective of CLAMS was to validate satellite-based retrievals of aerosol properties and vertical profiles of the radiative flux, temperature and water vapor. Six research aircraft were deployed to make detailed coincident measurements of the atmosphere and ocean surface with the research satellites that orbited overhead. The mesoscale weather modeling system runs in real-time to provide high spatial and temporal resolution for forecasts that are delivered via the World Wide Web along with a variety of satellite imagery and satellite location predictions. This system is a multi-purpose modeling system capable of both data analysis/assimilation and multi-scale NWP ranging from cloud-scale to larger than regional scale. This is a three-dimensional, nonhydrostatic compressible model in a terrain-following coordinate. The model employs advanced numerical techniques and contains detailed interactive physical processes. The utility of the forecasting system is illustrated throughout the discussion on the impact of the surface-wind forecast on BRDF (Bidirectional Reflectance Distribution Function) and the description of the cloud/moisture forecast versus the aircraft measurement.

  5. US plant and radiation dosimetry experiments flown on the soviet satellite COSMOS 1129. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, M.R.; Souza, K.A.

    1981-05-01

    Experiments included: 30 young male Wistar SPF rats used for wide range physiological studies Kosmos Satellites experiments with plants, fungi, insects, and mammalian tissue cultures; radiation physics experiments; a heat convection study; a rat embryology experiment in which an attempt was made to breed 2 male and 5 female rats during the flight; and fertile quail eggs used to determine the effects of spaceflight on avian embryogenesis. Specimens for US experiments were initially prepared at the recovery site or in Moscow and transferred to US laboratories for complete analyses. An overview of the mission focusing on preflight, on orbit, and postflight activities pertinent to the fourteen US experiments aboard Cosmos 1129 is presented.

  6. Satellite laser ranging experiment with sub-centimeter single-shot ranging precision at Shanghai Observatory

    Institute of Scientific and Technical Information of China (English)

    YANG; Fumin(杨福民); CHEN; Wanzhen(陈婉珍); ZHANG; Zhongping(张忠萍); CHEN; Juping(陈菊平); HU; Jingfu(扈荆夫); LI; Xin(李鑫); I.; Prochazka; K.; Hamal

    2003-01-01

    The Shanghai Astronomical Observatory, Chinese Academy of Sciences, incollaboration with the Czech Technical University, carried out the experiment of satellite laser ranging with sub-centimeter precision in Shanghai in August 2001. A pico-second event timer was used for the measurement of the time interval between the transmitted and returned laser pulses for Lageos 1, 2, Starlette, Stella, Topex/Poseiden and ERS-2 in coordination with the existing laser transmitting and receiving system at the Shanghai Observatory. The analysis of the measurement showed that the single-shot ranging precision with these satellites is 7-8 mm. In order to compare ranging precision, the existing ranging system has tracked simultaneously these satellites and obtained the ranging precision of 12-15 mm. It means that the ranging precision with the new system is 80% better thanthe existing system. The systematic biases with the existing system have also been checked in the experiment.

  7. Combined Release and Radiation Effects Satellite (CRRES) Experiment: Educational planning and coordination

    Science.gov (United States)

    Vaughan, William W.; Alzmann, Melanie

    1991-01-01

    The efforts conducted to provide educational planning and development support for the Combined Release and Radiation Satellite (CRRES) Experiment are summarized. Activities regarding the scientific working group and workshop development are presented including the preparation of descriptive information on the CRRES Project.

  8. Testing fundamental physics with laser ranged satellites: perspectives and goals of the LARASE experiment

    Science.gov (United States)

    Lucchesi, David; Anselmo, Luciano; Pardini, Carmen; Peron, Roberto; Pucacco, Giuseppe; Visco, Massimo

    Passive laser-ranged satellites, launched for geodynamics and geophysics purposes, not only have contributed to significant measurements in space geodesy that enabled, among several aspects, a deeper knowledge of the Earth's geopotential (both in its static and dynamic behavior), as well as of the geocenter motion and GM value up to the definition of the terrestrial reference frame, but they also provided an outstanding test bench to fundamental physics, as in the case of the first measurement of the Lense-Thirring precession on the combined nodes of the two LAGEOS satellites, or in the case of the total relativistic precession of the argument of pericenter of LAGEOS II. Indeed, the physical characteristics of such satellites -- such as their low area-to-mass ratio -- as well as those of their orbits, and the availability of high-quality tracking data provided by the International Laser Ranging Service (ILRS), allow for precise tests of gravitational theories. The aim of LARASE (LAser RAnged Satellites Experiment) is to go a step further in the tests of the gravitational interaction in the field of Earth, i.e. in the weak-field and-slow motion limit of general relativity, by the joint analysis of the orbits of the two LAGEOS satellites and that of the most recent LARES satellite. One of the key ingredients to reach such a goal is to provide high-quality updated models for the perturbing non-gravitational forces acting on the surface of such satellites. A large amount of Satellite Laser Ranging (SLR) data of LAGEOS and LAGEOS II has been analyzed using a set of dedicated models for satellite dynamics, and the related post-fit residuals have been analyzed. A parallel work is on-going in the case of LARES that, due to its much lower altitude, is subject to larger gravitational and non-gravitational effects; the latter are mitigated in part by its much lower area-to-mass ratio. Recent work on the data analysis of the orbit of such satellites will be presented together

  9. CTS digital video college curriculum-sharing experiment. [Communications Technology Satellite

    Science.gov (United States)

    Lumb, D. R.; Sites, M. J.

    1974-01-01

    NASA-Ames Research Center, Stanford University, and Carleton University, Ottawa, Canada, are participating in a joint experiment to evaluate the feasibility and effectiveness of college curriculum sharing using compressed digital television and the Communications Technology Satellite (CTS). Each university will offer televised courses to the other during the 1976-1977 academic year via CTS, a joint program by NASA and the Canadian Department of Communications. The video compression techniques to be demonstrated will enable economical interconnection of educational institutions using existing and planned domestic satellites.

  10. A variable bandwidth assignment scheme for the Land Mobile Satellite experiment

    Science.gov (United States)

    Yan, T.-Y.; Li, V. O. K.

    The Mobile Satellite Experiment is a proposed experimental satellite-based communications network which provides data and voice communications to mobile terminals dispersed in geographically dispersed areas. In this paper, an analytical model is developed to calculate the performance of a Variable Bandwidth Assignment (VBA) Scheme. Under this scheme, the satellite channel bandwidth is dynamically reassigned so that a message may be transmitted in the shortest possible time. To transmit a long message, message channels will be reconfigured to have more bandwidth such that the transmission time is reduced, while to transmit a short message, the channel bandwidth will be shrunk such that the released bandwidth can be used to serve other messages. The model is illustrated with numerical examples. It is shown that a VBA scheme can achieve considerable improvement in transmission delays over a Fixed Bandwidth Assignment Scheme.

  11. Registration of ELF waves in rocket-satellite experiment with plasma injection

    Science.gov (United States)

    Korobeinikov, V. G.; Oraevskii, V. N.; Ruzhin, Iu. Ia.; Sobolev, Ia. P.; Skomarovskii, V. S.; Chmyrev, V. M.; Namazov, C. A.; Pokhunkov, A. A.; Nesmeianov, V. I.

    1992-12-01

    Two rocket KOMBI-SAMA experiments with plasma injection at height 100-240 km were performed in August 1987 in the region of Brazilian magnetic anomaly (L = 1.25). The launching time of the rocket was determined so that plasma injection was at the time when COSMOS 1809 satellite passed as close as possible to magnetic tube of injection. Caesium plasma jet was produced during not less than 300 s by an electric plasma generator separated from the payload. When the satellite passed the geomagnetic tube intersecting the injection region an enhancement of ELF emission at 140 Hz, 450 Hz by a factor of 2 was registered on board the satellite. An enhancement of energetic particle flux by a factor of 4-5 was registered on board the rocket. Observed ELF emission below 100 Hz is interpreted as the generation of oblique electromagnetic ion-cyclotron waves due to drift plasma instability at the front of the plasma jet.

  12. Analysis of Hongdao Clam Industrial Structure Based on Industry Chain

    Institute of Scientific and Technical Information of China (English)

    Jiang; Xianqiong

    2014-01-01

    The vertical and transverse structures of Hongdao clam industry are described and analyzed objectively based on the perspective of industry chain. On the basis of field investigation,the key nodes of Hongdao clam industry chain,including nursery,breeding,processing,transportation and sale,are analyzed. It can be concluded that the development of clam industry chain is unbalanced,especially the deep-processing capacity is not strong,and the development of supporting industy lags behind. The horizontal industry chain of clam needs to be further improved. The corresponding suggestions are put forward: strengthening research on new nursery technology in later period,further extending the horizontal industry chain of clam,mining the depth of clam-related leisure industry,and upgrading service level of leisure travel.

  13. Trans-Pacific HDR Satellite Communications Experiment Phase-2 Project Plan and Experimental Network

    Science.gov (United States)

    Hsu, Eddie; Kadowaki, Naoto; Yoshimura, Naoko; Takahashi, Takashi; Yoshikawa, Makoto; Bergman, Larry; Bhasin, Kul

    2000-01-01

    The trans-Pacific high data rate (TP-HDR) satellite communications experiment was proposed at the Japan-U.S. Cooperation in Space (JUCS) Program Workshop held in Hawaii in 1993 and remote high definition video post-production was demonstrated as the first phase trial. ATM-based 45 Mbps trans-Pacific link was established in the first phase, and the following experiments with 155 Mbps was planned as the phase 2. This paper describes the experimental network configuration and project plan of TP-HDR experiment phase 2. Additional information is provided in the original.

  14. Effects of stocking density on intermediate culture of the razor clam Ensis arcuatus (Pharidae: Bivalvia)

    OpenAIRE

    Da Costa Gonzalez, Fiz; Barreiro, Berta; Ojea, Justa; Novoa, Susana; Martinez-patino, Dorotea

    2015-01-01

    Commercial production of most bivalve species involves a phase of intermediate cultivation during which juveniles are grown under protected conditions until they can be transferred to the final grow-out location. Consequently, the aim of this study was investigating the effect of density on growth and survival in the intermediate culture of the razor clam Ensis arcuatus in raft. Two series of experiments were performed, using in the first experiment two holding systems: 5-L plastic bottles an...

  15. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae)

    OpenAIRE

    UDHI EKO HERNAWAN

    2012-01-01

    Hernawan E. 2012. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae). Biodiversitas 13: 118-123. A taxonomic study was conducted on the giant clam’s specimens deposited in Museum Zoologicum Bogoriense (MZB), Cibinong Indonesia. Taxonomic overviews of the examined specimens are given with diagnostic characters, remarks, habitat and distribution. Discussion is focused on specific characters distinguishing each species. From seven species known to distribute in Indonesian waters, there ...

  16. ATS-6 - A satellite for human needs. [Health, Education, Telecommunications Experiment

    Science.gov (United States)

    Whalen, A. A.; Johnston, W. A., Jr.

    1975-01-01

    On May 30, 1974, NASA launched the ATS-6 experimental communications satellite into a geosynchronous orbit at a station centered over the United States. The 1400 kg satellite was designed to be body-stabilized with a 3-axis control system capable of precision offset pointing. It deployed a 9.1 meter (30 foot) parabolic reflector antenna with a transponder that covered a frequency range from VHF through C-band. The high RF gains obtained with the antenna were to be used for many dramatic communications experiments, one of which was the Health/Education Telecommunications Experiment (HET), a demonstration of direct broadcast of color television to low cost terminals in remote regions of the United States. More than 120 terminals with 3-meter antennas were deployed in Alaska, Washington, the Rocky Mountains, and Appalachia to provide educational and health services to selected community centers. After 11 months of nearly continuous service, the performance of both the satellite and the experiment have exceeded all expectations.

  17. ATS-6 - A satellite for human needs. [Health, Education, Telecommunications Experiment

    Science.gov (United States)

    Whalen, A. A.; Johnston, W. A., Jr.

    1975-01-01

    On May 30, 1974, NASA launched the ATS-6 experimental communications satellite into a geosynchronous orbit at a station centered over the United States. The 1400 kg satellite was designed to be body-stabilized with a 3-axis control system capable of precision offset pointing. It deployed a 9.1 meter (30 foot) parabolic reflector antenna with a transponder that covered a frequency range from VHF through C-band. The high RF gains obtained with the antenna were to be used for many dramatic communications experiments, one of which was the Health/Education Telecommunications Experiment (HET), a demonstration of direct broadcast of color television to low cost terminals in remote regions of the United States. More than 120 terminals with 3-meter antennas were deployed in Alaska, Washington, the Rocky Mountains, and Appalachia to provide educational and health services to selected community centers. After 11 months of nearly continuous service, the performance of both the satellite and the experiment have exceeded all expectations.

  18. Satellite clock corrections estimation to accomplish real time ppp: experiments for brazilian real time network

    Science.gov (United States)

    Marques, Haroldo; Monico, João; Aquino, Marcio; Melo, Weyller

    2014-05-01

    that the phase ambiguities are eliminated when applying differences between consecutive epochs. However, when using undifferenced code and phase, the ambiguities may be estimated together with receiver clock errors, satellite clock corrections and troposphere parameters. In both strategies it is also possible to correct the troposphere delay from a Numerical Weather Forecast Model instead of estimating it. The prediction of the satellite clock correction can be performed using a straight line or a second degree polynomial using the time series of the estimated satellites clocks. To estimate satellite clock correction and to accomplish real time PPP two pieces of software have been developed, respectively, "RT_PPP" and "RT_SAT_CLOCK". The system (RT_PPP) is able to process GNSS code and phase data using precise ephemeris and precise satellites clocks corrections together with several corrections required for PPP. In the software RT_SAT_CLOCK we apply a Kalman filter algorithm to estimate satellite clock correction in the network PPP mode. In this case, all PPP corrections must be applied for each station. The experiments were generated in real time and post-processed mode (simulating real time) considering data from the Brazilian continuous GPS network and also from the IGS network in a global satellite clock solution. We have used IGU ephemeris for satellite position and estimated the satellite clock corrections, performing the updates as soon as new ephemeris files were available. Experiments were accomplished in order to assess the accuracy of the estimated clocks when using the Brazilian Numerical Weather Forecast Model (BNWFM) from CPTEC/INPE and also using the ZTD from European Centre for Medium-Range Weather Forecasts (ECMWF) together with Vienna Mapping Function VMF or estimating troposphere with clocks and ambiguities in the Kalman Filter. The daily precision of the estimated satellite clock corrections reached the order of 0.15 nanoseconds. The clocks were

  19. Optimization of hard clams, polychaetes, physical disturbance and denitrifying bacteria of removing nutrients in marine sediment.

    Science.gov (United States)

    Shen, Hui; Thrush, Simon F; Wan, Xihe; Li, Hui; Qiao, Yi; Jiang, Ge; Sun, Ruijian; Wang, LiBao; He, Peimin

    2016-09-15

    Marine organisms are known to play important roles in transforming nutrients in sediments, however, guidelines to optimize sediment restoration are not available. We conducted a laboratory mesocosm experiment to investigate the role of hard clams, polychaetes, the degree of physical disturbance and denitrifying bacterial concentrations in removing total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in marine sediments. Response surface methodology was employed to analyze the results of initial experiments and in a subsequent experiment identified optimal combinations of parameters. Balancing the TN, TP, TOC removal efficiency, our model predicted 39% TN removal, 33% TP removal, and 42% TOC removal for a 14-day laboratory bioremediation trial using hard clams biomass of 1.2kgm(-2), physical disturbance depth of 16.4cm, bacterial density of 0.18Lm(-2), and polychaetes biomass of 0.16kgm(-2), respectively. These results emphasize the value of combining different species in field-based bioremediation.

  20. On-orbit flight results from the reconfigurable cibola flight experiment satellite (CFEsat)

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, Michael [Los Alamos National Laboratory; Morgan, Keith [Los Alamos National Laboratory; Roussel-dupre, Diane [LANL; Robinson, Scott [Los Alamos National Laboratory; Nelson, Anthony [Los Alamos National Laboratory; Salazar, Anthony [Los Alamos National Laboratory; Wirthlin, Michael [BYU; Howes, William [BYU; Richins, Daniel [BYU

    2009-01-01

    The Cibola Flight Experiment (CFE) is an experimental small satellite developed at the Los Alamos National Laboratory to demonstrate the feasibility of using FPGA-based reconfigurable computing for sensor processing in a space environment. The CFE satellite was launched on March 8, 2007 in low-earth orbit and has operated extremely well since its deployment. The nine Xilinx Virtex FPGAs used in the payload have been used for several high-throughput sensor processing applications and for single-event upset (SEU) monitoring and mitigation. This paper will describe the CFE system and summarize its operational results. In addition, this paper will describe the results from several SEU detection circuits that were performed on the spacecraft.

  1. World′s first telepathology experiments employing WINDS ultra-high-speed internet satellite, nicknamed "KIZUNA"

    Directory of Open Access Journals (Sweden)

    Takashi Sawai

    2013-01-01

    Full Text Available Background: Recent advances in information technology have allowed the development of a telepathology system involving high-speed transfer of high-volume histological figures via fiber optic landlines. However, at present there are geographical limits to landlines. The Japan Aerospace Exploration Agency (JAXA has developed the "Kizuna" ultra-high speed internet satellite and has pursued its various applications. In this study we experimented with telepathology in collaboration with JAXA using Kizuna. To measure the functionality of the Wideband InterNet working engineering test and Demonstration Satellite (WINDS ultra-high speed internet satellite in remote pathological diagnosis and consultation, we examined the adequate data transfer speed and stability to conduct telepathology (both diagnosis and conferencing with functionality, and ease similar or equal to telepathology using fiber-optic landlines. Materials and Methods: We performed experiments for 2 years. In year 1, we tested the usability of the WINDS for telepathology with real-time video and virtual slide systems. These are state-of-the-art technologies requiring massive volumes of data transfer. In year 2, we tested the usability of the WINDS for three-way teleconferencing with virtual slides. Facilities in Iwate (northern Japan, Tokyo, and Okinawa were connected via the WINDS and voice conferenced while remotely examining and manipulating virtual slides. Results: Network function parameters measured using ping and Iperf were within acceptable limits. However; stage movement, zoom, and conversation suffered a lag of approximately 0.8 s when using real-time video, and a delay of 60-90 s was experienced when accessing the first virtual slide in a session. No significant lag or inconvenience was experienced during diagnosis and conferencing, and the results were satisfactory. Our hypothesis was confirmed for both remote diagnosis using real-time video and virtual slide systems, and also

  2. A satellite observation system simulation experiment for carbon monoxide in the lowermost troposphere

    Science.gov (United States)

    Edwards, David P.; Arellano, Avelino F.; Deeter, Merritt N.

    2009-07-01

    We demonstrate the feasibility of using observing system simulation experiment (OSSE) studies to help define quantitative trace gas measurement requirements for satellite missions and to evaluate the expected performance of proposed observing strategies. The 2007 U.S. National Research Council Decadal Survey calls for a geostationary (GEO) satellite mission for atmospheric composition and air quality applications (Geostationary Coastal and Air Pollution Events Mission (GEO-CAPE)). The requirement includes a multispectral (near-infrared and thermal infrared) measurement of carbon monoxide (CO) at high spatiotemporal resolution with information on lowermost troposphere concentration. We present an OSSE to assess the improvement in surface CO characterization that would result from the addition of a GEO-CAPE CO measurement to current low Earth orbit (LEO) thermal infrared-only measurements. We construct instrument simulators for these two measurement scenarios and study the case of July 2004 when wildfires in Alaska and Canada led to significant CO pollution over the contiguous United States. Compared to a control experiment, an ensemble-based data assimilation of simulated satellite observations in a global model leads to improvements in both the surface CO distributions and the time evolution of CO profiles at locations affected by wildfire plumes and by urban emissions. In all cases, an experiment with the GEO-CAPE CO measurement scenario (overall model skill of 0.84) performed considerably better than the experiment with the current LEO/thermal infrared measurement (skill of 0.58) and the control (skill of 0.07). This demonstrates the advantages of increased sampling from GEO and enhanced measurement sensitivity to the lowermost troposphere with a multispectral retrieval.

  3. The behaviour of giant clams (Bivalvia: Cardiidae: Tridacninae).

    Science.gov (United States)

    Soo, Pamela; Todd, Peter A

    2014-01-01

    Giant clams, the largest living bivalves, live in close association with coral reefs throughout the Indo-Pacific. These iconic invertebrates perform numerous important ecological roles as well as serve as flagship species-drawing attention to the ongoing destruction of coral reefs and their associated biodiversity. To date, no review of giant clams has focussed on their behaviour, yet this component of their autecology is critical to their life history and hence conservation. Almost 100 articles published between 1865 and 2014 include behavioural observations, and these have been collated and synthesised into five sections: spawning, locomotion, feeding, anti-predation, and stress responses. Even though the exact cues for spawning in the wild have yet to be elucidated, giant clams appear to display diel and lunar periodicities in reproduction, and for some species, peak breeding seasons have been established. Perhaps surprisingly, giant clams have considerable mobility, ranging from swimming and gliding as larvae to crawling in juveniles and adults. Chemotaxis and geotaxis have been established, but giant clams are not phototactic. At least one species exhibits clumping behaviour, which may enhance physical stabilisation, facilitate reproduction, or provide protection from predators. Giant clams undergo several shifts in their mode of acquiring nutrition; starting with a lecithotrophic and planktotrophic diet as larvae, switching to pedal feeding after metamorphosis followed by the transition to a dual mode of filter feeding and phototrophy once symbiosis with zooxanthellae (Symbiodinium spp.) is established. Because of their shell weight and/or byssal attachment, adult giant clams are unable to escape rapidly from threats using locomotion. Instead, they exhibit a suite of visually mediated anti-predation behaviours that include sudden contraction of the mantle, valve adduction, and squirting of water. Knowledge on the behaviour of giant clams will benefit

  4. Variable conductance heat pipe technology. [research project resulting in heat pipe experiment on OAO-3 satellite

    Science.gov (United States)

    Anderson, W. T.; Edwards, D. K.; Eninger, J. E.; Marcus, B. D.

    1974-01-01

    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.

  5. 20 Years Experience with using Low Cost Launch Opportunities for 20 Small Satellite Missions

    Science.gov (United States)

    Meerman, Maarten; Sweeting, Martin, , Sir

    these larger 'small satellites' are too big to be carried 'piggy-back'. The entrepreneurial efforts of leading FSU rocket &missile organisations in converting existing vehicles to meet the small satellite launch market at an appropriate cost has resulted in the FSU now holding the prime position for providing launches for the small satellite community - and with an excellent track record of successful launches. However, negotiating and completing a Launch Services Agreement (LSA) for a nano-micro-minisatellite with any launcher organisation is a complex matter and risky territory for the unwary or inexperienced who may easily fall prey to unexpected additional costs and delays. Whilst this warning should be heeded when dealing with European and US organisations, it is particularly relevant when negotiating launches from the FSU where there is a plethora of agencies and organisations offering a bewildering range of launch vehicles and options. Furthermore, the FSU has developed a very different technical and managerial philosophy towards launchers when compared with the west and this can be unnerving to 'first-time buyers'. Organisations experienced in dealing in the FSU will encounter a different but excellent service - once the launch service agreement has been thoroughly and fiercely negotiated in every detail. The inexperienced, however, have encountered frustrating delays, lost opportunities, unexpected taxes and costs for additional services or facilities not originally specified, and bewilderment at the different procedures used in the FSU. Fortunately, all this can be avoided with proper experience and the FSU is the current mainstay for launching small satellites quickly, affordably and reliably. Surrey has unique experience gathered over 20 years in handling launches for 20 small satellites, ranging from a 6kg nanosatellite, 50-100kg microsatellites, and a 325kg minisatellite, using 7 different launchers from the USA, Russia, Ukraine, and Europe. By working

  6. Manila clam Venerupis philippinarum as a biomonitor to metal pollution

    Institute of Scientific and Technical Information of China (English)

    WU Huifeng; JI Chenglong; WANG Qing; LIU Xiaoli; ZHAO Jianmin; FENG Jianghua

    2013-01-01

    The Manila clam Venerupis philippinarum is a good biomonitor/bioindicator to marine metal pollution and is frequently used in aquatic toxicology.Two dominant pedigrees (white and zebra) of clam are distributed in the Bohai Sea; however,little attention has been paid to potential biological differences between these two pedigrees.In this study,we tested the sensitivity of both pedigrees to marine metal (cadmium and zinc) pollution biomonitoring and marine environmental toxicology.Results demonstrate significant biological differences in gills of white and zebra clams based on metabolic profiles and antioxidant enzyme activities.In addition,we found that hypotaurine,malonate and homarine were relatively high in white clam gills,while alanine,arginine,glutamate,succinate,4-aminobutyrate,taurine and betaine were high in zebra clam gills.Zebra clam gills were also more sensitive to a mixture of Cd and Zn,as shown by antioxidant enzyme activities and metabolic profiles,but white clam gills could accumulate more Zn.Therefore,we suggest that the white pedigree can be used as a biomonitor to marine Zn pollution,whereas the zebra pedigree can be used for toxicology studies on Cd and Zn mixed pollution.

  7. Autochthonous clams monitoring of Ganzirri Lake (Sicily).

    Science.gov (United States)

    Di Bella, Giuseppa; Cavallaro, Novella; Lo Turco, Vincenzo; Furci, Patrizia; Rando, Rossana; La Pera, Lara; Dugo, Giacomo

    2010-12-01

    Two autochthonous clams, Venerupis aurea laeta and Cerastoderma edule/glaucum, collected for a period of 1 year, from May 2007 to January 2008, were studied in the Cape Peloro lagoon. On the samples, it was evaluated the presence of pathogenic microorganisms and proteins, lipids and yield edible part were determined. It was evaluated the concentration of mineral elements (Cd, Cu, Mn, Se, Pb, Zn) and organic contaminants (∑DDT and PCBs). Salmonella is never present in any sample. Total and faecal coliform values have always been under law limits for alive bivalves mussels production and sale. Zn, Cu, Cd and Pb levels were found in clams where they are slightly lower too. Both species do not show significant changes for Mn and Se. DDT and PCBs traces were discovered in Ganzirri Lake' samples, but in all observed cases, they were below law limits. As a result of all these observations, it is clear that, in recent years, the bivalve's use of Ganzirri Lake does not denote toxicological risk to human health.

  8. Interaction of CLAM Steel with Plasma in HT-7 Tokamak During High Parameter Operation

    Institute of Scientific and Technical Information of China (English)

    LI Chunjing; HUANG Qunying; FENG Yan; LI Jiangang; KONG Mingguang

    2007-01-01

    A Plasma Surface Interaction(PSI)experiment on China Low Activation Martensitic(CLAM)steel was done to check if CLAM steel could be used as a Plasma Facing Material (PFM).A specimen with a diameter of 45 mm was exposed to 897 shots of deuterium plasmas with a total duration of 712 sec at a minor radius of 30 cm in HT-7 tokamak.During the exposure experiment,no observable influence Was found on plasma performance.After exposure,the surface of the specimen seemed as smooth as before but with some colour change at the margin of the specimen.Even though some micro-damage,such as dense blisters,melting,splashing,depositions,and dust,Was found on local surfaces with Scanning Electron Microscopic(SEM)observation.The reflectivity of the specimen decreased only slightly.All of these shows CLAM steel has good stability and irradiation resistance.With further optimization,it could possibly be used as the first mirror material for plasma diagnostics in tokamaks.

  9. Scenarios and performance measures for advanced ISDN satellite design and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1991-01-01

    Described here are the contemplated input and expected output for the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and Full Service ISDN Satellite (FSIS) Models. The discrete event simulations of these models are presented with specific scenarios that stress ISDN satellite parameters. Performance measure criteria are presented for evaluating the advanced ISDN communication satellite designs of the NASA Satellite Communications Research (SCAR) Program.

  10. A radiation belt monitor for the High Energy Transient Experiment Satellite

    Science.gov (United States)

    Lo, D. H.; Wenzel, K. W.; Petrasso, R. D.; Prigozhin, G. Y.; Doty, J.; Ricker, G.

    1993-01-01

    A Radiation Belt Monitor (RBM) sensitive to protons and electrons with energy approximately greater than 0.5 MeV has been designed for the High Energy Transient Experiment (HETE) satellite in order to: first, control the on-off configuration of the experiments (i.e. those susceptible to proton damage); and second, to indicate the presence of proton and/or electron events that could masquerade as legitimate high energy photon events. One of the two RBM channels has an enhanced sensitivity to electrons. Each channel of the RBM, based on a PIN silicon diode, requires a typical power of 6 milliwatts. Tests have been performed with protons with energies from approximately 0.1 to 2.5 MeV (generated by a Cockcroft-Walton linear accelerator via the d(d,p)t reaction), and with electrons with energies up to 1 MeV (from a 1.0 microcurie Bi-207 source).

  11. Razor clam to RoboClam: burrowing drag reduction mechanisms and their robotic adaptation.

    Science.gov (United States)

    Winter, A G; V; Deits, R L H; Dorsch, D S; Slocum, A H; Hosoi, A E

    2014-09-01

    Estimates based on the strength, size, and shape of the Atlantic razor clam (Ensis directus) indicate that the animal's burrow depth should be physically limited to a few centimeters; yet razor clams can dig as deep as 70 cm. By measuring soil deformations around burrowing E. directus, we have found the animal reduces drag by contracting its valves to initially fail, and then fluidize, the surrounding substrate. The characteristic contraction time to achieve fluidization can be calculated directly from soil properties. The geometry of the fluidized zone is dictated by two commonly-measured geotechnical parameters: coefficient of lateral earth pressure and friction angle. Calculations using full ranges for both parameters indicate that the fluidized zone is a local effect, occurring between 1-5 body radii away from the animal. The energy associated with motion through fluidized substrate-characterized by a depth-independent density and viscosity-scales linearly with depth. In contrast, moving through static soil requires energy that scales with depth squared. For E. directus, this translates to a 10X reduction in the energy required to reach observed burrow depths. For engineers, localized fluidization offers a mechanically simple and purely kinematic method to dramatically reduce energy costs associated with digging. This concept is demonstrated with RoboClam, an E. directus-inspired robot. Using a genetic algorithm to find optimal digging kinematics, RoboClam has achieved localized fluidization burrowing performance comparable to that of the animal, with a linear energy-depth relationship, in both idealized granular glass beads and E. directus' native cohesive mudflat habitat.

  12. PlumeSat: A Micro-Satellite Based Plume Imagery Collection Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G.; Ng, L.C.

    2002-06-30

    This paper describes a technical approach to cost-effectively collect plume imagery of boosting targets using a novel micro-satellite based platform operating in low earth orbit (LEO). The plume collection Micro-satellite or PlueSat for short, will be capable of carrying an array of multi-spectral (UV through LWIR) passive and active (Imaging LADAR) sensors and maneuvering with a lateral divert propulsion system to different observation altitudes (100 to 300 km) and different closing geometries to achieve a range of aspect angles (15 to 60 degrees) in order to simulate a variety of boost phase intercept missions. The PlumeSat will be a cost effective platform to collect boost phase plume imagery from within 1 to 10 km ranges, resulting in 0.1 to 1 meter resolution imagery of a variety of potential target missiles with a goal of demonstrating reliable plume-to-hardbody handover algorithms for future boost phase intercept missions. Once deployed on orbit, the PlumeSat would perform a series phenomenology collection experiments until expends its on-board propellants. The baseline PlumeSat concept is sized to provide from 5 to 7 separate fly by data collects of boosting targets. The total number of data collects will depend on the orbital basing altitude and the accuracy in delivering the boosting target vehicle to the nominal PlumeSat fly-by volume.

  13. Real-time horizontality adjusting and control system of a large platform applied to satellite experiment

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shi-sheng; ZHANG Shi-peng; WANG Rui

    2007-01-01

    In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temperature with real time. So the control system design and control strategy are described in detail to accomplish the horizontality monitoring and adjusting. The system adopts the industry control computer as the upper computer and the SIEMENS S7-300 PLC as the lower computer. The upper computer that bases on industry configuration software IFIX takes charge of monitoring the platform and puts forward the control strategy. PLC takes charge of receiving the adjusting instructions and controlling the legs moving to accomplish the horizontality adjusting. The horizontality adjusting strategy is emphasized and the concept of grads is introduced to establish a mathematics model of the platform inclined state, so the adjusting method is obtained. Accordingly the key question of the automatic horizontality adjusting is solved in this control system.

  14. The evolution of satellite-monitored radio tags for large whales: One laboratory's experience

    Science.gov (United States)

    Mate, Bruce; Mesecar, Roderick; Lagerquist, Barbara

    2007-02-01

    Despite several centuries of whaling and directed research, there are only a few whale stocks whose year-round whereabouts are reasonably well known. For the vast majority of depleted populations, the link between seasonal feeding and breeding concentrations remains unknown. This lack of information on range, seasonal distribution, stock structure, and migration routes makes it difficult to design and implement effective conservation measures to promote recovery. The use of such information would have been valuable to develop stock-specific quotas for whaling, but now it may be even more important for recovery of depleted stocks and identifying anthropogenic threats throughout a depleted stock's range. Building upon the preliminary findings of Discovery tags and more recent photo identification studies, satellite-monitored radio tags are now providing range and seasonal distribution information for many stocks of depleted large whales. These parameters are important to better estimate population abundance, characterize habitats, identify threats to recovery, and design effective protection measures when needed. This paper traces one laboratory's experience with the development of satellite-monitored radio tag technology for large whales, including attachment mechanisms and delivery systems, in the hope that others will profit from our successes and our mistakes. Selected examples are used to demonstrate how such tags contribute to new insights about whales' habitats, migrations, behaviour, and management.

  15. Composting clam processing wastes in a laboratory- and pilot-scale in-vessel system.

    Science.gov (United States)

    Hu, Zhenhu; Lane, Robert; Wen, Zhiyou

    2009-01-01

    Waste materials from the clam processing industry (offal, shells) have several special characteristics such as a high salinity level, a high nitrogen content, and a low C/N ratio. The traditional disposal of clam waste through landfilling is facing the challenges of limited land available, increasing tipping fees, and strict environmental and regulatory scrutiny. The aim of this work is to investigate the performance of in-vessel composting as an alternative for landfill application of these materials. Experiments were performed in both laboratory-scale (5L) and pilot-scale (120L) reactors, with woodchips as the bulking agent. In the laboratory-scale composting test, the clam waste and woodchips were mixed in ratios from 1:0.5 to 1:3 (w/w, wet weight). The high ratios resulted in a better temperature performance, a higher electrical conductivity, and a higher ash content than the low-ratio composting. The C/N ratio of the composts was in the range of 9:1-18:1. In the pilot-scale composting test, a 1:1 ratio of clam waste to woodchips was used. The temperature profile during the composting process met the US Environmental Protection Agency sanitary requirement. The final cured compost had a C/N ratio of 14.6, with an ash content of 167.0+/-14.1g/kg dry matter. In addition to the major nutrients (carbon, nitrogen, calcium, magnesium, phosphorus, potassium, sulfur, and sodium), the compost also contained trace amounts of zinc, manganese, copper, and boron, indicating that the material can be used as a good resource for plant nutrients.

  16. Design and experiments of an active isolator for satellite micro-vibration

    Institute of Scientific and Technical Information of China (English)

    Li Weipeng; Huang Hai; Zhou Xubin; Zheng Xintao; Bai Yang

    2014-01-01

    In this paper, a soft active isolator (SAI) derived from a voice coil motor is studied to determine its abilities as a micro-vibration isolation device for sensitive satellite payloads. Firstly, the two most important parts of the SAI, the mechanical unit and the low-noise driver, are designed and manufactured. Then, a rigid-flexible coupling dynamic model of the SAI is built, and a dynamic analysis is conducted. Furthermore, a controller with a sky-hook damper is designed. Finally, results from the performance tests of the mechanical/electronic parts and the isolation experiments are presented. The SAI attenuations are found to be more than ?20 dB above 5 Hz, and the control effect is stable.

  17. Design and experiments of an active isolator for satellite micro-vibration

    Directory of Open Access Journals (Sweden)

    Li Weipeng

    2014-12-01

    Full Text Available In this paper, a soft active isolator (SAI derived from a voice coil motor is studied to determine its abilities as a micro-vibration isolation device for sensitive satellite payloads. Firstly, the two most important parts of the SAI, the mechanical unit and the low-noise driver, are designed and manufactured. Then, a rigid-flexible coupling dynamic model of the SAI is built, and a dynamic analysis is conducted. Furthermore, a controller with a sky-hook damper is designed. Finally, results from the performance tests of the mechanical/electronic parts and the isolation experiments are presented. The SAI attenuations are found to be more than −20 dB above 5 Hz, and the control effect is stable.

  18. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae

    Directory of Open Access Journals (Sweden)

    UDHI EKO HERNAWAN

    2012-07-01

    Full Text Available Hernawan E. 2012. Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae. Biodiversitas 13: 118-123. A taxonomic study was conducted on the giant clam’s specimens deposited in Museum Zoologicum Bogoriense (MZB, Cibinong Indonesia. Taxonomic overviews of the examined specimens are given with diagnostic characters, remarks, habitat and distribution. Discussion is focused on specific characters distinguishing each species. From seven species known to distribute in Indonesian waters, there are six species, Tridacna squamosa Lamarck, 1819; T. gigas Linnaeus, 1758; T. derasa Roding, 1798; T. crocea Lamarck, 1819; T. maxima Roding,1798; and Hippopus hippopus Linnaeus, 1758. This study suggests the need for collecting specimen of H. porcellanus Rosewater, 1982. Important characters to distinguish species among Tridacninae are interlocking teeth on byssal orifice, life habits, presence of scales and inhalant siphon tentacles.

  19. Photosymbiotic Giant Clams are Transformers of Solar Flux

    Science.gov (United States)

    2014-01-01

    photosymbiosis. We discovered that the mantle tissue of giant clams, which harbours symbiotic nutrition-providing microalgae , contains a layer of iridescent cells...geometrically coupled to the vertically pillared microalgae , resulting in an even re-distribution of the incoming light 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND...tissue of giant clams, which harbours symbiotic nutrition-providing microalgae , contains a layer of iridescent cells called iridocytes that serve to

  20. Observation of TGFs onboard "Vernov" satellite and TGEs in ground-based experiments

    Science.gov (United States)

    Bogomolov, Vitaly; Panasyuk, Mikhail; Svertilov, Sergey; Garipov, Gali; Iyudin, Anatoly; Klimov, Pavel; Morozenko, Violetta; Maximov, Ivan; Mishieva, Tatiana; Klimov, Stanislav; Pozanenko, Alexey; Rothkaehl, Hanna

    2016-04-01

    "Vernov" satellite with RELEC experiment on-board was launched on 2014 July, 8 into a polar solar-synchronous orbit. The payload includes DRGE gamma-ray spectrometer providing measurements in 10-3000 keV energy range with four detectors directed to atmosphere. Total area of DRGE detectors is ~500 cm2. The data were recorded both in monitoring and gamma by gamma modes with timing accuracy ~15 us. Several TGF candidates with 10-40 gammas in a burst with duration instruments on-board "Vernov" satellite shows the absence of significant electromagnetic pulses around correspondent time moments. Comparison with WWLLN lightning network data base also indicates that there were no thunderstorms connected with most of detected TGF candidates. Possible connection of these flashes with electron precipitations is discussed. Ground-based experiments, with similar gamma-spectrometers were conducted, to study the spectral, temporal and spatial characteristics of TGEs in 20-3000 keV energy range, as well, as to search the fast hard X-ray and gamma-ray flashes possibly appearing at the moment of lightning. The time of each gamma-quantum interaction was recorded with an ~15 us s accuracy together with detailed spectral data. Measurements were done on the ground at Moscow region, and at mountain altitude in Armenia at Aragatz station. During the time interval covering spring, summer and autumn of 2015 a number of TGEs were detected. Measured low-energy gamma-ray spectra usually contain a set of lines that can be interpreted as radiation of Rn-222 daughter isotopes. The increase of Rn-222 radiation was detected during rainfalls with thunderstorm, as well, as during rainy weather without thunderstorms. Variations of Rn-222 radiation dominate at low energies (measure low energy gamma-radiation from the electrons accelerated in thunderclouds. There were no significant flashes with duration of ~1ms detected in coincidence with a nearby lightnings.

  1. CRRES (Combined Release and Radiation Effects Satellite) SPACERAD plasma wave experiment

    Science.gov (United States)

    Anderson, Roger R.; Gurnett, Donald A.

    1988-10-01

    This document discusses the Main Electronics Package, two Electric Field Preamps and Search Coil Magnetometer for the AFGL 701 SPACERAD instrumentation on the CRRES (Combined Release and Radiation Effects Satellite) project. This document discusses the scientific objectives and the importance of the Plasma Wave Experiment in the CRRES SPACERAD mission and describes the instrument design rational and the instrument development philosophy. This document also discusses the testing and operations of the experiment and contains a schematic drawing of the instrumentation electronics and lists of the schematics, drawings, and wiring diagrams that describe the as-built configuration of the Plasma Wave Experiment instrumentation. Problems encountered during the construction and testing of the instrument and their resolutions are discussed. Test results from already completed environmental and EMC/RFI tests have already been submitted to AFGL and to the Air Force Headquarters Space Division Space Test Program. The recertification of the calibration of the instrument is recommended in the near future under a new contract covering the re-delivery (necessitated due to the removal during the launch-delay storage period), pre-launch, and launch operations.

  2. From Earth to Heaven: Using `Newton's Cannon' Thought Experiment for Teaching Satellite Physics

    Science.gov (United States)

    Velentzas, Athanasios; Halkia, Krystallia

    2013-10-01

    Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) `Newton's Cannon' was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a teaching-interview designed and implemented according to the Teaching Experiment methodology and (b) an open-ended questionnaire administered to students 2 weeks after the teaching-interview. The sample consisted of forty students divided into eleven groups. The teaching and learning processes which occurred during the teaching-interview were recorded and analyzed. The findings of the present study show that the use of the TE helped students to mentally construct a physical system which has nothing to do with their everyday experience (i.e. they had to imagine themselves as observers in a context in which the whole Earth was visible) and to draw conclusions about phenomena within this system. Specifically, students managed (1) to conclude that if an object is appropriately launched, it may be placed in an orbit around the Earth and to support this conclusion by giving necessary arguments, and (2) to realize that the same laws of physics describe, on the one hand, the motion of the Moon around the Earth (and the motion of other celestial bodies as well) and, on the other hand, the motion of `terrestrial' objects (i.e. objects on the Earth, such as a tennis ball). The main difficulties students met were caused by their idea that there is no gravity in the vacuum (i.e. the area outside of the Earth's atmosphere) and also by their everyday experience, according to which it is impossible for a projectile to move continuously parallel to the ground.

  3. Results from an experiment that collected visible-light polarization data using unresolved imagery for classification of geosynchronous satellites

    Science.gov (United States)

    Speicher, Andy; Matin, Mohammad; Tippets, Roger; Chun, Francis; Strong, David

    2015-05-01

    In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved images of geosynchronous satellites taken over various solar phase angles. Different collection geometries were used to evaluate the polarization contribution of solar arrays, thermal control materials, antennas, and the satellite bus as the solar phase angle changed. Since materials on space objects age due to the space environment, their polarization signature may change enough to allow discrimination of identical satellites launched at different times. Preliminary data suggests this optical signature may lead to positive identification or classification of each satellite by an automated process on a shorter timeline. The instrumentation used in this experiment was a United States Air Force Academy (USAFA) Department of Physics system that consists of a 20-inch Ritchey-Chrétien telescope and a dual focal plane optical train fed with a polarizing beam splitter. Following a rigorous calibration, polarization data was collected during two nights on eight geosynchronous satellites built by various manufacturers and launched several years apart. When Stokes parameters were plotted against time and solar phase angle, the data indicates that a polarization signature from unresolved images may have promise in classifying specific satellites.

  4. Complementing the ground-based CMB Stage-4 experiment on large scales with the PIXIE satellite

    CERN Document Server

    Calabrese, Erminia; Dunkley, Jo

    2016-01-01

    We present forecasts for cosmological parameters from future Cosmic Microwave Background (CMB) data measured by the Stage-4 (S4) generation of ground-based experiments in combination with large-scale anisotropy data from the PIXIE satellite. We demonstrate the complementarity of the two experiments and focus on science targets that benefit from their combination. We show that a cosmic-variance-limited measurement of the optical depth to reionization provided by PIXIE, with error $\\sigma(\\tau)=0.002$, is vital for enabling a 5$\\sigma$ detection of the sum of the neutrino masses when combined with a CMB-S4 lensing measurement, and with lower-redshift constraints on the growth of structure and the distance-redshift relation. Parameters characterizing the epoch of reionization will also be tightly constrained; PIXIE's $\\tau$ constraint converts into $\\sigma(\\rm{z_{re}})=0.2$ for the mean time of reionization, and a kinematic Sunyaev-Zel'dovich measurement from S4 gives $\\sigma(\\Delta \\rm{z_{re}})=0.03$ for the du...

  5. Results of the ISEDE Experiment Encompassing Disaggregated Electronics on an all Inflatable Satellite on Board the BEXUS 16 Balloon

    Science.gov (United States)

    Sinn, T.; de Franca Queiroz, T.; Brownlie, F.; Allan, A.; Leite, L.; Rowan, A.; Gillespie, J.; Vasile, M.

    2015-09-01

    Traditional satellites have a rigid structure defining the basic configuration of the satellite and holding in place all subsystems. A variation of the shape or configuration of the satellite is normally achieved through the use of deployable structures or appendices (antennas, solar anays, booms, etc.). Although modern structural solutions are modular and multifunctional, the structure of a satellite still represents a significant portion of its mass and a limitation on the achievable configuration, extension of deployable components and packing efficiency during launch. The goal of this project is to design and build an initial prototype of an all-inflatable satellite with disaggregated electronics for deployment on-board a BEXUS balloon as proof of concept. The idea is to use inflatable cell structures as support for all the subsystems composing a typical nano-satellite. Each subsystem and component is mounted on a different cell. Cells are both individually inflated and individually controlled. The aim is to design and build an inflatable satellite, demonstrating the deployment, communication among components and local control enabling structure shape adaption via soft robotic actuators and micro pumps. The experiment will deploy two inflatable structures made of 5x2 cells which are packed in a lOxlOxlOcm3 cubesat reaching a size of 70x18x14cm3 once deployed. Flexible circuitry was used to mount all the electronic subsystems on the surface of the folded inflatable. The experiment was flown onboard the BEXUS16 stratospheric balloon to an altitude of 27,3km for 2 hours and 45mm from the Swedish space port ESRANGE on the 8th of October 2013 proving the functionality of the disaggregated electronics.

  6. Low cycle fatigue properties of CLAM steel at 823 K

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xue [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049 (China); Huang, Lixin [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yan, Wei; Wang, Wei [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Sha, Wei [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, Belfast BT9 5AG (United Kingdom); Shan, Yiyin, E-mail: yyshan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Yang, Ke, E-mail: kyang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2014-09-08

    China Low Activation Martensitic (CLAM) steel is considered to be the main candidate material for the first wall components of future fusion reactors in China. In this paper, the low cycle fatigue (LCF) behavior of CLAM steel is studied under fully reversed tension–compression loading at 823 K in air. Total strain amplitude was controlled from 0.14% to 1.8% with a constant strain rate of 2.4×10{sup −3} s{sup −1}. The corresponding plastic strain amplitude ranged from 0.023% to 1.613%. The CLAM steel displayed continuous softening to failure at 823 K. The relationship between strain, stress and fatigue life was obtained using the parameters obtained from fatigue tests. The LCF properties of CLAM steel at 823 K followed Coffin–Manson relationship. Furthermore, irregular serration was observed on the stress–strain hysteresis loops of CLAM steel tested with the total strain amplitude of 0.45–1.8%, which was attributed to the dynamic strain aging (DSA) effect. During continuous cyclic deformation, the microstructure and precipitate distribution of CLAM steel changed gradually. Many tempered martensitic laths were decomposed into subgrains, and the size and number of M{sub 23}C{sub 6} carbide and MX carbonitride precipitates decreased with the increase of total strain amplitude. The response cyclic stress promoted the recovery of martensitic lath, while the thermal activation mainly played an important role on the growth of precipitates in CLAM steel at 823 K. In order to have a better understanding of high-temperature LCF behavior, the potential mechanisms controlling stress–strain response, DSA phenomenon and microstructure changes have also been evaluated.

  7. Satellite/Terrestrial Networks: End-to-End Communication Interoperability Quality of Service Experiments

    Science.gov (United States)

    Ivancic, William D.

    1998-01-01

    Various issues associated with satellite/terrestrial end-to-end communication interoperability are presented in viewgraph form. Specific topics include: 1) Quality of service; 2) ATM performance characteristics; 3) MPEG-2 transport stream mapping to AAL-5; 4) Observation and discussion of compressed video tests over ATM; 5) Digital video over satellites status; 6) Satellite link configurations; 7) MPEG-2 over ATM with binomial errors; 8) MPEG-2 over ATM channel characteristics; 8) MPEG-2 over ATM over emulated satellites; 9) MPEG-2 transport stream with errors; and a 10) Dual decoder test.

  8. Razor clam (Ensis directus) shell as a low-cost adsorbent for the removal of Congo red and Rhodamine B dyes from aqueous solution

    Science.gov (United States)

    Areibat, Lila Elamari Mohamed; Kamari, Azlan

    2017-05-01

    Wastewater originating from industrial effluents contains many types of pollutants including dyes. Anionic and cationic dyes are very toxic and they can cause several problems to aquatic system. In present study, razor clam shell was used as a potential adsorbent to remove two classes of dyes, namely anionic (Congo red, CR) and cationic (Rhodamine B, RB) dyes from aqueous solution. Batch adsorption experiments were performed to study the effects of three experimental parameters, namely solution pH, adsorbent dosage and initial dye concentration, on adsorption capacity of CR and RB onto razor clam shell. Results indicated that pH 2.0 was optimum pH for adsorbent to adsorb both CR and RB. At an initial concentration of 20 mg/L, the removal percentages of CR and RB were 97% and 38%, respectively. The Freundlich and Langmuir isotherm models were used to describe adsorption behaviour of CR and RB, as well as the relationship between adsorbent and adsorbate. The adsorption equilibrium data were well fitted to Freundlich isotherm model. The separation factor (RL) constants suggest that both CR and RB were favourably adsorbed by razor clam shell. Razor clam shell was characterised by using two techniques, namely Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectrometry (FTIR). Overall, this study suggests that razor clam shell has great potential to be an alternative to expensive adsorbents.

  9. Ornithinibacillus scapharcae sp. nov., isolated from a dead ark clam.

    Science.gov (United States)

    Shin, Na-Ri; Whon, Tae Woong; Kim, Min-Soo; Roh, Seong Woon; Jung, Mi-Ja; Kim, Young-Ok; Bae, Jin-Woo

    2012-01-01

    A novel Gram-positive, aerobic, motile, hemolytic, endospore-forming and rod-shaped bacterium TW25(T) was isolated from a dead ark clam during a mass mortality event on the South coast of Korea. The strain grew optimally at 30°C, at pH 8-9, and with 1% (w/v) NaCl. The 16S rRNA gene sequence analysis indicated that strain TW25(T) was associated with the genus Ornithinibacillus and that it was most closely related to the type strain of Ornithinibacillus californiensis (98.5% similarity). The dominant cellular fatty acids were iso-C15:0, anteiso-C15:0 and C16:0. The peptidoglycan amino acid type was A4β, containing L: -ornithine and D: -aspartic acid. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, four unidentified phospholipids, two unidentified aminolipids and two unidentified lipids. The major respiratory quinone was menaquinone-7 (MK-7). The G + C content of genomic DNA was 36.7 mol%. DNA-DNA hybridization experiments with related strains revealed lower than 11 ± 3% relatedness. Based on this polyphasic taxonomic study, strain TW25(T) represents a novel species in the genus Ornithinibacillus, for which the name Ornithinibacillus scapharcae sp. nov. is proposed. The type strain is TW25(T) (=KACC 15116(T) = JCM 17314(T)).

  10. Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.

    Science.gov (United States)

    Groesbeck, Amy S; Rowell, Kirsten; Lepofsky, Dana; Salomon, Anne K

    2014-01-01

    Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.

  11. Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today.

    Directory of Open Access Journals (Sweden)

    Amy S Groesbeck

    Full Text Available Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.

  12. Traffic model for advanced satellite designs and experiments for ISDN services

    Science.gov (United States)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The data base structure and fields for categorizing and storing Integrated Services Digital Network (ISDN) user characteristics is outlined. This traffic model data base will be used to exercise models of the ISDN Advanced Communication Satellite to determine design parameters and performance for the NASA Satellite Communications Applications Research (SCAR) Program.

  13. Toxicity of a traditional molluscicide to asian clam veligers

    Science.gov (United States)

    Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

    2014-01-01

    Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

  14. An Efficient Method of Noroviruses Recovery from Oysters and Clams

    Institute of Scientific and Technical Information of China (English)

    ZHOU Deqing; MA Liping; ZHAO Feng; YAO Lin; SU Laijin; LI Xinguang

    2013-01-01

    Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis.Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish.The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish.This study aimed to select a simple,rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR.Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams,respectively,were compared,of them,the method involving proteinase K and PEG 8000 was found the most efficient.With this method,9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams,respectively.This method was further used to detect NoVs in 84 oysters (Crassostrea gigas) and 86 clams (Ruditapes philippinarum) collected from 10 coastal cities in China from Jan.2011 to Feb.2012.The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84).All the detected NoVs belonged to genotype GII.The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

  15. An efficient method of noroviruses recovery from oysters and clams

    Science.gov (United States)

    Zhou, Deqing; Ma, Liping; Zhao, Feng; Yao, Lin; Su, Laijin; Li, Xinguang

    2013-03-01

    Noroviruses (NoVs) are widespread causes of nonbacterial gastroenteritis. Outbreaks of NoVs caused diseases are commonly ascribed to the consumption of contaminated shellfish. The concentration and RNA extraction of NoVs are crucial steps of detecting NoVs in shellfish. This study aimed to select a simple, rapid and highly efficient recovery method of NoVs detection with real-time RT-PCR. Four methods of recovering GI.3 and GII.4 NoVs from spiked digestive tissues of oysters and clams, respectively, were compared, of them, the method involving proteinase K and PEG 8000 was found the most efficient. With this method, 9.3% and 13.1% of GI.3 and GII.4 NoVs were recovered from oysters and 9.6% and 12.3% of GI.3 and GII.4 NoVs were recovered from clams, respectively. This method was further used to detect NoVs in 84 oysters ( Crassostrea gigas) and 86 clams ( Ruditapes philippinarum) collected from 10 coastal cities in China from Jan. 2011 to Feb. 2012. The NoVs isolation rates were 10.47% of clams (9/86) and 7.14% of oysters (6/84). All the detected NoVs belonged to genotype GII. The NoVs recovery method selected is efficient for NoVs detection in oysters and clams.

  16. Life characteristics assessment of the communications technology satellite transmitter experiment package

    Science.gov (United States)

    Smetana, J.; Curren, A. N.

    1979-01-01

    The performance characteristics of the transmitter experiment package (TEP) aboard the Communications Technology Satellite (CTS) measured during its first 2 years in orbit are presented. The TEP consists of a nominal 200 watt output stage tube (OST), a supporting power processing system (PPS), and a variable conductance heat pipe system (VCHPS). The OST, a traveling wave tube augmented with a 10 stage depressed collector has an overall saturated average efficiency of 51.5 percent and an average saturated radio frequency (rf) output power at center band frequency of 240 watts. The PPS operated with a measured efficiency of 86.5 to 88.5 percent. The VCHPS, using three pipes to conduct heat from the PPS and the OST to a 52 by 124 centimeter radiator fin, maintained the PPS baseplate temperature below 50 C for all operating conditions. The TEP performance characteristics presented include frequency response, rf output power, thermal performance, and efficiency. Communications characteristics were evaluated by using both video and audio modulated signals. On four occasions, the TEP experienced temporary thermal control system malfunctions. The anomalies were terminated safely, and the problem was investigated because of the potential for TEP damage due to the signficant temperature increases. Safe TEP operating procedures were established.

  17. Assessing the mineralogy and hydration of rocky cores of satellites: insights from experiments and thermodynamics

    Science.gov (United States)

    Reynard, B.; Neri, A.; Sotin, C.

    2016-12-01

    Icy satellites and similar objects likely form from a mixture of hydrated rocky material, such as the CI chondrites, and various amounts of ices. Mass-balance estimates show that hydrous silicates such as serpentine, and brucite, the simple Mg-Fe hydroxide, dominate fully hydrated mineralogy. The inferred iron content of these minerals is, however, very dependent on assumptions of iron redox state, and whether it forms sulfides or segregates into a metal core. From the determination of the moment of inertia inferred from gravity measurements at Jupiter and Saturn by the Galileo and Cassini spacecraft, Ganymede and Europa would have a differentiated iron-rich core whereas Titan and Enceladus would not. Whatever the case, iron content is generally significantly higher than that of the terrestrial ultrabasic rocks used as analogs in modeling of hydrated satellite cores. Thus, we investigated the phase relations of iron-rich ultrabasic systems based on chondritic composition by combining thermodynamic modeling and preliminary high-pressure experiments. Our starting composition model is that of CI carbonaceous chondrites. Stable mineral assemblages are calculated with the PerpleX package (Connolly, 1990), assuming excess water, and various amounts of iron in the silicate phase through varying the amount of iron sulfide (troilite) or iron oxide (magnetite). Results show stable hydrated minerals are serpentine, chlorite, brucite, Na-phlogopite and in extreme cases, talc in the 1.5-5 GPa range relevant to bodies larger than about 1000 km in radius. Dehydration temperatures are extremely sensitive to the iron content, hence on the chosen amount of iron bearing phase (troilite or magnetite), and to a lower extent on average CI composition. An experimental approach was developed to simulate hydrous alteration of CI-like material. A mixture of synthetic silicates, troilite, and organic compounds, to which excess water is added, is used. Mineralogy and composition is checked

  18. Scientific results from the SABER Experiment on the TIMED Satellite: 2002 - 2011

    Science.gov (United States)

    Russell, J. M.; Mlynczak, M. G.

    2011-12-01

    The primary science goal of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment on the TIMED satellite is to achieve major advances in understanding the structure, energetics, chemistry, and dynamics in the atmospheric region extending from 60 to 180 km altitude. The SABER instrument has been observing the atmosphere nearly continuously since data collection began in January of 2002 using the technique of spectral broadband limb emission radiometry applied in 10 infrared spectral bands ranging from 1.27 to 17μm. Four bands - three in the 15μm band and one in the 4.3μm band of CO2, are used to retrieve temperature and CO2 concentrations and to correct retrievals for spacecraft motion effects. The remaining bands are used to retrieve O3, H2O, [O], [H],and energetics parameters, and to measure atmospheric heating and cooling. The measured limb emission profiles are being processed on the ground to provide vertical temperature, constituent and other parameter profiles with 2 km altitude resolution. Measurements are made both night and day over the latitude range from 52 degrees to 83 degrees with alternating hemisphere coverage every 60 days. During the time SABER has been operating, many solar storms have occurred and data have been collected over the range from solar maximum in 2002 to the 2009 solar minimum and up to the present day. The temporal and geographic coverage provided by SABER has provided path finding observations on the atmospheric effects of these events. In addition, the battery of measurements made by SABER has yielded new information on atmospheric energetics effects over the solar cycle including radiative cooling due to the 15μm CO2 and 5.3μm NO bands. Numerous synergistic science studies have been conducted with data from the AIM satellite that is dedicated to the study of noctilucent clouds (NLCs) including the driving parameters that control the start and end of the NLC season, the relationship between

  19. Status and improvement of CLAM for nuclear application

    Science.gov (United States)

    Huang, Qunying

    2017-08-01

    A program for China low activation martensitic steel (CLAM) development has been underway since 2001 to satisfy the material requirements of the test blanket module (TBM) for ITER, China fusion engineering test reactor and China fusion demonstration reactor. It has been undertaken by the Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences under wide domestic and international collaborations. Extensive work and efforts are being devoted to the R&D of CLAM, such as mechanical property evaluation before and after neutron irradiation, fabrication of scaled TBM by welding and additive manufacturing, improvement of its irradiation resistance as well as high temperature properties by precipitate strengthening to achieve its final successful application in fusion systems. The status and improvement of CLAM are introduced in this paper.

  20. Microstructure evolution of CLAM steel during creep at 923K

    Science.gov (United States)

    Ye, S.; Zhao, F.; Huang, F.; He, J.; Wang, J. L.

    2017-08-01

    The microstructure change of CLAM steel during creep testing process was investigated at the temperature of 923K with different stress. The results show that the fragmentation and polygonization of martensite lath, as well as the degeneration of dislocation structure are the main factors to deteriorate the creep performance. The stability of MX precipitates in CLAM steel during high temperature creep is good, but the amount and size of M23C6 precipitates are increased. The Laves phase was not found in all samples, which may be due to the experimental temperature is close to the dissolution temperature of Laves phase. The higher temperature accelerates the microstructure evolution of CLAM steel, which results in the degradation of creep properties.

  1. Performance Characteristics of AOAC Method 2005.06 for the Determination of Paralytic Shellfish Toxins in Manila Clams, European Otter Clams, Grooved Carpet Shell Clams, Surf Clams, and Processed King Scallops.

    Science.gov (United States)

    O'Neill, Alison; Turner, Andrew D

    2015-01-01

    An approach was developed for the verification of method performance of the AOAC 2005.06 LC-fluorescence detector (FLD) method for determination of paralytic shellfish poisoning (PSP) toxins in bivalve shellfish. This was developed following advice published by the Analytical Laboratory Accreditation Criteria Committee and applied to shellfish species that had not been previously subjected to a full single-laboratory validation scheme. The refined approach was developed following the need to assess performance in a number of shellfish species infrequently monitored through the UK statutory monitoring program, while reducing the impact and cost of the studies, most notably in terms of the use of valuable reference standards. The species assessed were manila clams (Ruditapes philippinarum), European otter clams (Lutraria lutraria), grooved carpet shell clams (R. decussatus), surf clams (Spisula solida), and king scallops (Pecten maximus) presented as adductor only or adductor plus roe. The method was assessed for sensitivity in terms of LOD and LOQ, toxin recovery, and method precision in each species. It incorporated the PSP toxins deemed toxic and/or prevalent in UK samples and commercially available as certified reference standards. The toxins studied included GTX1-5, dcSTX, STX, C1&2, and NEO. The toxins dcGTX2&3 were included for surf clams due to the prevalence of these toxins in this species as a result of toxin decarbamoylation. Method performance targets were met for each of the characteristics investigated. Consequently, the method was deemed fit for purpose for the screening and quantification of these clam and scallop species for PSP toxins by AOAC Method 2005.06 LC-FLD.

  2. Impact of modelling foreground uncertainties on future CMB polarization satellite experiments

    Science.gov (United States)

    Hervías-Caimapo, Carlos; Bonaldi, Anna; Brown, Michael L.

    2017-07-01

    We present an analysis of errors on the tensor-to-scalar ratio due to residual diffuse foregrounds. We use simulated observations of a cosmic microwave background (CMB) polarization satellite, the Cosmic Origins Explorer (COrE), using the specifications of the version proposed to ESA in 2010. We construct a full pipeline from microwave sky maps to r likelihood, using two models of diffuse Galactic foregrounds with different complexity and assuming component separation with varying degrees of accuracy. Our pipeline uses a linear mixture (generalized least squares) solution for component separation, and a hybrid approach for power spectrum estimation, with a quadratic maximum likelihood estimator at low ℓs and a pseudo-Cℓ deconvolution at high ℓs. In the likelihood for r, we explore modelling foreground residuals as nuisance parameters. Our analysis aims at measuring the bias introduced in r by mismodelling the foregrounds and to determine what error is tolerable while still successfully detecting r. We find that r = 0.01 can be measured successfully even for a complex sky model and in the presence of foreground parameters error. However, the detection of r = 0.001 is a lot more challenging, as inaccurate modelling of the foreground spectral properties may result in a biased measurement of r. Once biases are eliminated, the total error on r allows setting an upper limit rather than a detection, unless the uncertainties on the foreground spectral indices are very small, i.e. equal or better than 0.5 per cent error for both dust and synchrotron. This emphasizes the need for pursuing research on component separation and foreground characterization in view of next-generation CMB polarization experiments.

  3. The impact of ocean acidification on the early life stages of surf clams and the interactive effects of feeding and temperature from laboratory experiment studies from 2011-07-12 to 2012-06-17 (NODC Accession 0123314)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains laboratory experiment data that were collected to examine the effects of ocean acidification on the Atlantic surfclam, Spisula...

  4. Can ecological history influence response to pollutants? Transcriptomic analysis of Manila clam collected in different Venice lagoon areas and exposed to heavy metal.

    Science.gov (United States)

    Milan, Massimo; Matozzo, Valerio; Pauletto, Marianna; Di Camillo, Barbara; Giacomazzo, Matteo; Boffo, Luciano; Binato, Giovanni; Marin, Maria Gabriella; Patarnello, Tomaso; Bargelloni, Luca

    2016-05-01

    Chronic exposure to environmental pollutants can exert strong selective pressures on natural populations, favoring the transmission over generations of traits that enable individuals to survive and thrive in highly impacted environments. The lagoon of Venice is an ecosystem subject to heavy anthropogenic impact, mainly due to the industrial activities of Porto Marghera (PM), which led to a severe chemical contamination of soil, groundwater, and sediments. Gene expression analysis on wild Manila clams collected in different Venice lagoon areas enabled to identify differences in gene expression profiles between clams collected in PM and those sampled in clean areas, and the definition of molecular signatures of chemical stress. However, it remains largely unexplored to which extent modifications of gene expression patterns persists after removing the source of contamination. It is also relatively unknown whether chronic exposure to xenobiotics affects the response to other chemical pollutants. To start exploring such issues, in the present study a common-garden experiment was coupled with transcriptomic analysis, to compare gene expression profiles of PM clams with those of clams collected in the less impacted area of Chioggia (CH) during a period under the same control conditions. Part of the two experimental groups were also exposed to copper for seven days to assess whether different "ecological history" does influence response to such pollutant. The results obtained suggest that the chronic exposure to chemical pollution generated a response at the transcriptional level that persists after removal for the contaminated site. These transcriptional changes are centered on key biological processes, such as defense against either oxidative stress or tissue/protein damage, and detoxification, suggesting an adaptive strategy for surviving in the deeply impacted environment of Porto Marghera. On the other hand, CH clams appeared to respond more effectively to copper

  5. Impact of cadmium contamination and oxygenation levels on biochemical responses in the Asiatic clam Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Legeay, Alexia [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France)]. E-mail: a.legeay@epoc.u-bordeaux1.fr; Achard-Joris, Maud [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Baudrimont, Magalie [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Massabuau, Jean-Charles [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France); Bourdineaud, Jean-Paul [Laboratoire d' Ecophysiologie et Ecotoxicologie des Systemes Aquatiques (LEESA), UMR 5805-OASU, Universite Bordeaux 1 and CNRS, Place Peyneau, 33120 Arcachon (France)

    2005-09-10

    The aim of this work was to evaluate the potential utility of several biochemical parameters as indicators of the toxic effects of cadmium in the freshwater clam Corbicula fluminea under two levels of oxygenation (normoxia 21 kPa and hypoxia 4 kPa). These variations in oxygenation are representative of the natural environments of bivalves living at the bottom of the water column, where hypoxic episodes may occur regularly. Cadmium accumulation, metallothionein synthesis, MXR protein induction, lipoperoxidation and antioxidant enzyme activities (catalase, glutathione reductase and total and selenium-dependent glutathione peroxidases) were assessed in the gills of C. fluminea in four experimental conditions: normoxia, hypoxia, normoxia with cadmium and hypoxia with cadmium ([Cd] = 30 {mu}g l{sup -1}) over a 14-day period. Behavioural reactions were also followed for the duration of the experiment by monitoring clam activity and valve movements. This study is a first report on biochemical responses under cadmium contamination and hypoxia and will enable us to determine better biomarkers for C. fluminea as they were measured simultaneously. In metal-exposed animals, we found an increasing accumulation of cadmium in the gills with time, and this was more severe in hypoxic conditions. Metallothionein synthesis occurred in contaminated clams and was precocious in hypoxic conditions. MXR protein induction appeared promising due to its quick and significant response to metal with a strong impact from hypoxic contamination. On the other hand, in our experimental conditions, antioxidant parameters did not show decisive responses to contamination and hypoxia, except glutathione peroxidases which decreased systematically with time in a cadmium-independent manner. Lipid peroxidation, expressed as malondialdehyde content, was not stimulated by normoxic contamination, as has been shown in other studies, but was stimulated under hypoxic cadmium contamination. Our study confirms the

  6. Microstructure and microhardness of CLAM steel irradiated up to 20.8 dpa in STIP-V

    Science.gov (United States)

    Peng, Lei; Ge, Hongen; Dai, Yong; Huang, Qunying; Ye, Minyou

    2016-01-01

    Specimens of China low activation martensitic (CLAM) steel were irradiated in the fifth experiment of SINQ target irradiation program (STIP-V) up to 20.8 dpa/1564 appm He. Microhardness measurements and transmission electron microscope (TEM) observations have been performed to investigate irradiation induced hardening effects. The results of CLAM steel specimens show similar trend in microhardness and microstructure changes with irradiation dose, compared to F82H/Optimax-A steels irradiated in STIP-I/II. Defects and helium bubbles were observed in all specimens, even at a very low dose of 5.4 dpa. For defects and bubbles, the mean size and number density increased with increasing irradiation dose to 13 dpa, and then the mean size increased and number density decreased with the increasing irradiation dose to 20.8 dpa.

  7. Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-Y. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, J.-W. [Institute of Ecology and Evolutionary Ecology, China Medical University, Taichung 40402, Taiwan (China); Ju, Y.-R. [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liao, C.-M., E-mail: cmliao@ntu.edu.t [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-05-15

    The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

  8. Solar irradiance observed on the FY-3 satellites - instrument overview and primary observation results of in-orbit experiments

    Science.gov (United States)

    Wang, H.; Fang, W.; Li, H.

    2015-12-01

    Solar driving mechanism for Earth climate has been a controversial problem for centuries. Data of Solar Irradiance (SI) is required by the investigations of the solar driving mechanism, including Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI). SI observations with short term accuracy and long term precision are essential to separate solar forcing from human-induced factors. TSI and SSI have been measured on Chinese FY-3 satellites, including FY-3A, FY-3B and FY-3C. FY-3A satellite launched in May, 2008 is the first satellite. FY-3B satellite launched in November, 2010 is the second satellite and FY-3C satellite launched in September, 2013 is the third satellite. SSI has been measured by SBUS (Solar Backscatter Ultraviolet Sounder) in the ultraviolet spectrum in the FY-3 mission. When a solar diffuser plate is deployed to reflect the incoming sunlight, SI is measured at 12 discrete, 1.1 nm wide wavelength bands between 250 nm and 340 nm. The SSI measurements are performed using a double monochromator operated in a stepped wavelength scan mode. SBUS collects SSI weekly at 12 discrete wave-lengths near polar area. Moreover, SSI is measured by SBUS every month covering 160-400 nm continuous spectral region. SSI has been recorded in SBUS missions since the ascending phase of Solar Cycle 24. Approximately the same variation tendencies of SSI were detected by SBUS in specific spectrum compared with data from SOLSTICE/SORCE. TSI have been recorded by Total Solar Irradiance Monitors (TSIM) in FY-3 missions. The sun was measured by TSIM/FY-3A and TSIM/FY-3B in a scanning manner. TSI data quality is improved by TSIM/FY-3C which has a pointing system. TSIM/FY-3C measures the sun with nearly zero solar pointing errors. TSI variations detected by TSIM/FY-3C are nearly the same with VIRGO/SOHO and TIM/SORCE. The TSIM experiments have observed the sun for about 7 years. A slowly increasing TSI trend has been detected by TSIMs in the Solar Cycle 24. We present the

  9. Near real time observational data collection for SPRUCE experiment- PakBus protocol for slow satellite connections

    Science.gov (United States)

    Krassovski, Misha; Hanson, Paul; Riggs, Jeff

    2017-04-01

    Climate change studies are one of the most important aspects of modern science and related experiments are getting bigger and more complex. One such experiment is the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE, http://mnspruce.ornl.gov) conducted in in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The SPRUCE experimental mission is to assess ecosystem-level biological responses of vulnerable, high carbon terrestrial ecosystems to a range of climate warming manipulations and an elevated CO2 atmosphere. This manipulation experiment generates a lot of observational data and requires a reliable onsite data collection system, dependable methods to transfer data to a robust scientific facility, and real-time monitoring capabilities. This publication shares our experience of establishing near real time data collection and monitoring system via a satellite link using PakBus protocol.

  10. Development status of CLAM steel for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qunying, E-mail: qunying.huang@fds.org.cn

    2014-12-15

    The China low activation martensitic (CLAM) steel is being developed at the Institute of Nuclear Energy Safety Technology (INEST) under wide collaboration within China. Significant R and D work on CLAM steel was carried out to help make it suitable for industrial applications. The effect of refining processes and thermal aging on composition, microstructures and mechanical properties were investigated. Material properties before irradiation including impact, fracture toughness, thermal aging, creep and fatigue properties etc. were assessed. A series of irradiation tests in the fission reactor HFETR in Chengdu up to 2 dpa and in the spallation neutron source SINQ in Paul Scherrer Institute up to 20 dpa were performed. PbLi corrosion tests for more than 10,000 h were done in the DRAGON-I and PICOLO loops. Fabrication techniques for a test blanket module (TBM) are being developed and a 1/3 scale TBM prototype is being fabricated with CLAM steel. Recent progresses on the development status of this steel are presented here. The code qualification of CLAM steel is under plan for its final application in ITER-TBM and DEMO in the future.

  11. Photosymbiotic giant clams are transformers of solar flux.

    Science.gov (United States)

    Holt, Amanda L; Vahidinia, Sanaz; Gagnon, Yakir Luc; Morse, Daniel E; Sweeney, Alison M

    2014-12-06

    'Giant' tridacnid clams have evolved a three-dimensional, spatially efficient, photodamage-preventing system for photosymbiosis. We discovered that the mantle tissue of giant clams, which harbours symbiotic nutrition-providing microalgae, contains a layer of iridescent cells called iridocytes that serve to distribute photosynthetically productive wavelengths by lateral and forward-scattering of light into the tissue while back-reflecting non-productive wavelengths with a Bragg mirror. The wavelength- and angle-dependent scattering from the iridocytes is geometrically coupled to the vertically pillared microalgae, resulting in an even re-distribution of the incoming light along the sides of the pillars, thus enabling photosynthesis deep in the tissue. There is a physical analogy between the evolved function of the clam system and an electric transformer, which changes energy flux per area in a system while conserving total energy. At incident light levels found on shallow coral reefs, this arrangement may allow algae within the clam system to both efficiently use all incident solar energy and avoid the photodamage and efficiency losses due to non-photochemical quenching that occur in the reef-building coral photosymbiosis. Both intra-tissue radiometry and multiscale optical modelling support our interpretation of the system's photophysics. This highly evolved 'three-dimensional' biophotonic system suggests a strategy for more efficient, damage-resistant photovoltaic materials and more spatially efficient solar production of algal biofuels, foods and chemicals.

  12. Measurement and analysis of SHCCT diagram for CLAM steel

    Science.gov (United States)

    Huang, Yuming; Chen, Xizhang; Shen, Zheng; Madigan, Bruce; Yucheng, Lei; Zhou, Jianzhong

    2013-01-01

    China Low Activation Martensitic (CLAM) steel is a leading candidate material for construction of the Chinese fusion reactor Test Blanket Module. The Simulated HAZ Continuous Cooling Transformation (SHCCT) diagram is developed via physical simulation, and the effects of thermal history on the microstructure and mechanical properties of the weld coarse-grain heat-affected zone (CGHAZ) in CLAM steel are evaluated. The results of thermal cycle simulation show that grain size increases and hardness decreases gradually with increasing heat input. Under certain conditions, especially when cooling times from 800 °C to 500 °C (T8/5) are larger than 136 s, delta ferrite may form which is deleterious for the TBM application. The amounts of delta ferrite are given under different T8/5. A SHCCT diagram of CLAM steel is developed using dilatometry and it predicts the AC1, AC3 and the Ms temperatures. With decreased cooling rate (larger T8/5), martensite laths widen and carbide precipitates grow. The results indicate that welding heat input should be taken into consideration and controlled in practical CLAM steel welding process applications.

  13. Measurement and analysis of SHCCT diagram for CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yuming [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Chen Xizhang, E-mail: kernel.chen@gmail.com [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Shen Zheng [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Madigan, Bruce [Montana Tech. of University of Montana, Butte, MT 59701 (United States); Yucheng, Lei [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Zhou Jianzhong [School of Mechanical Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China)

    2013-01-15

    China Low Activation Martensitic (CLAM) steel is a leading candidate material for construction of the Chinese fusion reactor Test Blanket Module. The Simulated HAZ Continuous Cooling Transformation (SHCCT) diagram is developed via physical simulation, and the effects of thermal history on the microstructure and mechanical properties of the weld coarse-grain heat-affected zone (CGHAZ) in CLAM steel are evaluated. The results of thermal cycle simulation show that grain size increases and hardness decreases gradually with increasing heat input. Under certain conditions, especially when cooling times from 800 Degree-Sign C to 500 Degree-Sign C (T8/5) are larger than 136 s, delta ferrite may form which is deleterious for the TBM application. The amounts of delta ferrite are given under different T8/5. A SHCCT diagram of CLAM steel is developed using dilatometry and it predicts the AC1, AC3 and the Ms temperatures. With decreased cooling rate (larger T8/5), martensite laths widen and carbide precipitates grow. The results indicate that welding heat input should be taken into consideration and controlled in practical CLAM steel welding process applications.

  14. Patterns in Clam Excurrent Siphon Velocity According to External Environmental Cues

    Science.gov (United States)

    Webster, D. R.; Delavan, S. K.

    2010-11-01

    This study attempts to determine the patterns and/or randomness of the excurrent velocity of actively feeding clams, Mercenaria mercenaria. We hypothesize that clams alter their feeding current velocity patterns or randomness according to external cues in the environment such as hydrodynamic characteristics, density of the clam patch, and presence of predators in the upstream flow. A PIV system measured vector fields for two-dimensional planes that bisect the clam excurrent siphons, and time records were extracted at the siphon exit position. Fractal and lacunarity analysis of the jet velocity time records revealed that clams alter their jet excurrent velocity unsteadiness according to the horizontal crossflow velocity. The results also reveal that the effect of clam patch density on the feeding activity was dependent on the size of the organism. This size/density dependent relationship suggests that predation by blue crabs dominates the system since larger clams are no longer susceptible to blue crab predation, whereas clams of all sizes are susceptible to whelk predation. Finally, clams increase the randomness of their excurrent jet velocity values when predator cues are located in the upstream flume flow. This suggests that the presence of predators elicits clam behavior that promotes the mixing and dilution of their chemical metabolites.

  15. Reproductive Biology of the Short-Necked Clam, Paphia undulata (Born 1778 from Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Fenelyn M. Nabuab

    2010-12-01

    Full Text Available The short-necked clam, Paphia undulata, occurs in coastal muddy bottoms of Hinigaran, Binalbagan, and Himamaylan, Negros Occidental where it has an important contribution to fisheries. However, stocks in these areas are dwindling and in order to formulate sound management strategies, information on the reproductive biology of this species is a prerequisite. Also, knowledge on the reproduction of this species is a prelude to its laboratory breeding and rearing. Reproductive biology of the short-necked clam from the three areas was studied over an annual cycle. Short-necked clams were collected monthly from catches of compressor divers. Five gonad stages were described based on histological examinations: developing, mature, partially spawned, redeveloping, and spent. Immature or indeterminate gonads were also noted. Although occasional presence of hermaphrodite gonads was observed this species is still functionally dioecious with 1.00M: 1.02F sex ratio. Sexual maturity is attained at 42.6 mm for males and 44.8 mm for females. Short-necked clams have continuous breeding season. However, peak of spawning activities is on the months of August to November which coincide with the monsoon transition months probably due to the decrease in salinity and nutrient influx during these months. Organisms smaller than 45mm must not be collected and collection must be regulated during peaks of spawning activities to leave a portion of reproductively mature individuals to ensure sustainability of fisheries. However, in terms of laboratory breeding and rearing of this species, it is fundamental to consider the spawning peaks and size at sexual maturity to ensure successful spawning in the laboratory. Hence, broodstock to be used in the experiments must be sexually mature (>45mm and collected during peaks of spawning activities.

  16. A study and experiment plan for digital mobile communication via satellite

    Science.gov (United States)

    Jones, J. J.; Craighill, E. J.; Evans, R. G.; Vincze, A. D.; Tom, N. N.

    1978-01-01

    The viability of mobile communications is examined within the context of a frequency division multiple access, single channel per carrier satellite system emphasizing digital techniques to serve a large population of users. The intent is to provide the mobile users with a grade of service consistant with the requirements for remote, rural (perhaps emergency) voice communications, but which approaches toll quality speech. A traffic model is derived on which to base the determination of the required maximum number of satellite channels to provide the anticipated level of service. Various voice digitalization and digital modulation schemes are reviewed along with a general link analysis of the mobile system. Demand assignment multiple access considerations and analysis tradeoffs are presented. Finally, a completed configuration is described.

  17. A depolarization and attenuation experiment using the COMSTAR and CTS satellites

    Science.gov (United States)

    Bostian, C. W.; Babula, S. M.; Dent, J. R.; Dombroski, R. E.; Lane, S. O.; Manus, E. A.; Marshall, R. E.; Meadows, D. N.; Stutzman, W. L.; Wiley, P. H.

    1979-01-01

    Monthly and annual percent-of-time data on ground rain fall rate and attenuation on satellite downlinks at 11.7 GHz, 19.04 GHz, and 28.56 GHz is presented. Equal probability values of attenuation and rain rate are compared for monthly, quarterly, half-year periods and for the entire year. Regression equations relating cross polarization isolation to the logarithm of attenuation are also presented.

  18. ACCORD Broadband ATM Satellite Experiment (BASE)-DS3 Ku-band channel

    Science.gov (United States)

    1997-12-01

    broadband ATM traf- fic. ATM was initially designed for fibre - optic media, i.e. a random error, low delay, and virtually error free channel...satellite links will soon be required to support broadband ATM traffic. ATM was initially designed for fibre - optic media, i.e. a random error, low...traffic generator and analyser. - Fibre Loop Converter: converts a DS-3 signal into a single-mode fibre optic signal and vice-versa. - EF Data Modem

  19. Continuation of the mission NINA: Nina-2 experiment on MITA satellite

    Science.gov (United States)

    Casolino, Marco

    NINA-2 is a silicon detector cosmic ray telescope to be launched on board the Italian satellite MITA by the end of 1999. Its physics objectives are to study - for a period of at least 3 years - the cosmic ray component for nuclei from Hydrogen to Iron in the energy range between 10 and 200 MeV/n. Furthermore, the segmented nature of the silicon strip detector will allow the detection outside the containment of particles up to 1 GeV/n. As the satellite will be placed in 87.3 degrees sun-synchronous polar orbit around the Earth, it will be able to detect particle of solar and galactic nature, studying long and short term transient phenomena such as solar modulation effects - as we move toward solar maximum - and the composition of solar flares. The interaction of the Sun with Earth's magnetosphere will also be observed. The characteristics of MITA on board computer system allowed a very fast hardware and software integration between the scientific payload and the satellite, optimising the device observational capabilities.

  20. Inactivation of Vibrio parahaemolyticus in hard clams (Mercanaria mercanaria) by high hydrostatic pressure (HHP) and the effect of HHP on the physical characteristics of hard clam meat.

    Science.gov (United States)

    Mootian, Gabriel K; Flimlin, George E; Karwe, Mukund V; Schaffner, Donald W

    2013-02-01

    Shellfish may internalize dangerous pathogens during filter feeding. Traditional methods of depuration have been found ineffective against certain pathogens. The objective was to explore high hydrostatic pressure (HHP) as an alternative to the traditional depuration process. The effect of HHP on the survival of Vibrio parahaemolyticus in live clams (Mercanaria mercanaria) and the impact of HHP on physical characteristics of clam meat were investigated. Clams were inoculated with up to 7 log CFU/g of a cocktail of V. parahaemolyticus strains via filter feeding. Clams were processed at pressures ranging from 250 to 552 MPa for hold times ranging between 2 and 6 min. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level (5 log reductions. The volume of clam meat (processed in shell) increased with negligible change in mass after exposure to pressure at 552 MPa for 3 min, while the drip loss was reduced. Clams processed at 552 MPa were softer compared to those processed at 276 MPa. However, all HHP processed clams were found to be harder compared to unprocessed. The lightness (L*) of the meat increased although the redness (a*) decreased with increasing pressure. Although high pressure-processed clams may pose a significantly lower risk from V. parahaemolyticus, the effect of the accompanied physical changes on the consumer's decision to purchase HHP clams remains to be determined. Shellfish may contain dangerous foodborne pathogens. Traditional methods of removing those pathogen have been found ineffective against certain pathogens. The objective of this research was to determine the effect of high hydrostatic pressure on V. parahaemolyticus in clams. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level, achieving >5 log reductions. © 2013 Institute of Food Technologists®

  1. Seasonal changes in physiological responses and evaluation of "well-being" in the Venus clam Chamelea gallina from the Northern Adriatic Sea.

    Science.gov (United States)

    Moschino, Vanessa; Marin, Maria Gabriella

    2006-12-01

    Chamelea gallina is an infaunal bivalve, widespread in sandy bottoms along Mediterranean coasts. It is an important economic resource for fisheries in the Adriatic, although in recent years over-fishing, and other concurrent factors, have dramatically decreased clam harvesting. In this context, it is of great interest to gain information on seasonal variations in the physiological performance of clams, for an overall evaluation of their well-being. In this study, laboratory experiments were performed to define allometric relationships and effects of temperature on clearance and respiration rates of C. gallina. The mean values of b coefficients were calculated and used to correlate physiological measurements to 'standard' body mass, when seasonally collected clams were analysed. The highest clearance rate (0.42 L h(-1)) was measured in clams collected in July 2000; the highest respiration rate (12.22 micromol O2 h(-1)) was observed in July 2001, leading to a negative scope for growth (-2.8 J h(-1)). The influence of environmental and endogenous factors, mostly reproduction, was discussed. Survival in air and condition indices, showing higher stress conditions in December 2000 and July 2001, were in good agreement with the other physiological measurements. The physiological responses examined in this study appear to be suitable for providing detailed indications on the well-being of C. gallina and may be useful for future studies aimed at eco-sustainable management of the resource.

  2. A possible experiment with two counter-orbiting drag-free satellites to obtain a new test of Einstein's general theory of relativity and improved measurements in geodesy

    Science.gov (United States)

    Van Patten, R. A.; Everitt, C. W. F.

    1976-01-01

    In 1918, Lense and Thirring calculated that a moon in orbit around a massive rotating planet would experience a nodal dragging effect due to general relativity. We describe an experiment to measure this effect by means of two counter-orbiting drag-free satellites in polar orbit about the earth. For a 2-1/2 year experiment, the measurement should approach an accuracy of 1%. An independent measurement of the geodetic precession of the orbit plane due to the motion about the sun may also be possible to about 10% accuracy. In addition to precision tracking data from existing ground stations, satellite-to-satellite Doppler data are taken at points of passing near the poles to yield an accurate measurement of the separation distance between the two satellites. New geophysical information on both earth harmonics and tidal effects is inherent in this polar ranging data.

  3. NWP Impact of Cloud Top and Boundary Layer Winds from a Satellite Borne Lidar: an Observing System Simulation Experiment

    Science.gov (United States)

    Isaacs, R. G.; Grassotti, C.; Hoffman, R. N.; Mickelson, M.; Nehrkorn, T.; Louis, J.-F.

    1992-01-01

    Observing systems simulation experiments (OSSE's) provide a powerful tool to assess the impact of proposed satellite borne observing systems on meteorological applications models. We describe the results of an OSSE conducted to assess the impact of data from a low power lidar wind sensor on the forecast accuracy of a global spectral numerical weather prediction (NWP) model, the Air Force Geophysics Laboratory Global Data Assimilation System. The instrument would be operating at near-infrared wavelengths thereby increasing the backscatter signal relative to comparable infrared lidar.

  4. Operational experience from the satellite fields Statfjord Nord and East; Driftserfaringer fra satellittfeltene Statfjord Nord og Oest

    Energy Technology Data Exchange (ETDEWEB)

    Retterdal, Atle; Hansen, Hans Birger [Statoil, Stavanger (Norway)

    1999-07-01

    Since production started on the satellite fields Statfjord Nord and East in 1995 and 1994, respectively, some opportunities for improvement have been discovered and realized both with respect to the subsea systems and the operational routines and philosophy. This presentation discusses the improvement projects. It is known from experience that creative ideas usually originate at the interfaces between supplier/customer, engineers with different backgrounds, or between different technologies. The interface between supplier and operator is very important for discovering creative solutions. The interface between Statoil and the suppliers of underwater equipment is not sufficiently well developed on the operational side.

  5. Ancient clam gardens, traditional management portfolios, and the resilience of coupled human-ocean systems

    Directory of Open Access Journals (Sweden)

    Julia Jackley

    2016-12-01

    Full Text Available Indigenous communities have actively managed their environments for millennia using a diversity of resource use and conservation strategies. Clam gardens, ancient rock-walled intertidal beach terraces, represent one example of an early mariculture technology that may have been used to improve food security and confer resilience to coupled human-ocean systems. We surveyed a coastal landscape for evidence of past resource use and management to gain insight into ancient resource stewardship practices on the central coast of British Columbia, Canada. We found that clam gardens are embedded within a diverse portfolio of resource use and management strategies and were likely one component of a larger, complex resource management system. We compared clam diversity, density, recruitment, and biomass in three clam gardens and three unmodified nonwalled beaches. Evidence suggests that butter clams (Saxidomus gigantea had 1.96 times the biomass and 2.44 times the density in clam gardens relative to unmodified beaches. This was due to a reduction in beach slope and thus an increase in the optimal tidal range where clams grow and survive best. The most pronounced differences in butter clam density between nonwalled beaches and clam gardens were found at high tidal elevations at the top of the beach. Finally, clam recruits (0.5-2 mm in length tended to be greater in clam gardens compared to nonwalled beaches and may be attributed to the addition of shell hash by ancient people, which remains on the landscape today. As part of a broader social-ecological system, clam garden sites were among several modifications made by humans that collectively may have conferred resilience to past communities by providing reliable and diverse access to food resources.

  6. Change in metallothionein phosphorylation state in Mya arenaria clams: implication in metal metabolism and oxidative stress

    OpenAIRE

    Gagné, F.; M Gélinas; Gagnon, C.; André, C.; C Blaise

    2010-01-01

    The contamination of the benthic environment poses a threat to long-lived sessile organisms such as clams. The purpose of this study was to investigate metal contamination in tissues and changes in metallothioneins (MT) in respect to its redox status in Mya arenaria clams collected at three polluted sites. The phosphorylation state of MT was also investigated to determine whether this state is changed in clams collected at heavy-metal contaminated site and its involvement in cytoprotective si...

  7. Infection of Manila clams Ruditapes philippinarum from Galicia (NW Spain) with a Mikrocytos-like parasite.

    Science.gov (United States)

    Ramilo, Andrea; Iglesias, David; Abollo, Elvira; González, Mar; Darriba, Susana; Villalba, Antonio

    2014-07-24

    The name 'microcells' is frequently used to refer to small-sized unicellular stages of molluscan parasites of the genera Bonamia (Rhizaria, Haplosporidia) and Mikrocytos (Rhizaria). Histological examination of Manila clams Ruditapes philippinarum revealed microcells in the connective tissue of adductor muscle, foot, mantle, gills, siphon and visceral mass. The clams had been collected from 4 beds on the coast of Galicia, Spain. The prevalence of these microcells ranged from 73 to 93% in surface clams and from 3 to 33% in buried clams. However, the detection of brown ring disease signs in clams from every bed prevented us from making the assumption that the microcells alone were responsible for clam mortality. PCR assays using primer pairs designed to detect Bonamia spp. and haplosporidians gave negative results, whereas positive results were obtained with primers for the genus Mikrocytos. A consensus sequence of 1670 bp of the ribosomal gene complex of the microcells was obtained. It contained a section of the 18S region, the whole first internal transcribed spacer, the 5.8S region, the second internal transcribed spacer and a section of the 28S region. Comparison of this sequence with those of M. mackini infecting Crassostrea gigas and Mikrocytos sp. infecting Ostrea edulis showed that the microcells of Galician clams were the most divergent among the compared parasites. This is the first report of a Mikrocytos-like parasite infecting Manila clams. Care must be taken to avoid the spread of this parasite through Manila clam transfers.

  8. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  9. Analysis and forecast experiments incorporating satellite soundings and cloud and water vapor drift wind information

    Science.gov (United States)

    Goodman, Brian M.; Diak, George R.; Mills, Graham A.

    1986-01-01

    A system for assimilating conventional meteorological data and satellite-derived data in order to produce four-dimensional gridded data sets of the primary atmospheric variables used for updating limited area forecast models is described. The basic principles of a data assimilation scheme as proposed by Lorenc (1984) are discussed. The design of the system and its incremental assimilation cycles are schematically presented. The assimilation system was tested using radiosonde, buoy, VAS temperature, dew point, gradient wind data, cloud drift, and water vapor motion data. The rms vector errors for the data are analyzed.

  10. TESIS experiment on XUV imaging spectroscopy of the Sun onboard the CORONAS-PHOTON satellite

    Science.gov (United States)

    Kuzin, S. V.; Zhitnik, I. A.; Bogachev, S. A.; Shestov, S. V.; Bugaenko, O. I.; Suhodrev, N. K.; Pertsov, A. A.; Mitrofanov, A. V.; Ignat'ev, A. P.; Slemzin, V. A.

    We present a brief description of new complex of space telescopes and spectrographs, TESIS, which will be placed aboard the CORONAS-PHOTON satellite. The complex is intended for high-resolution imaging observation of full Sun in the coronal spectral lines and in the spectral lines of the solar transition region. TESIS will be launched at the end of 2007 - early of 2008. About 25 % of the daily TESIS images will be free for use and for downloading from the TESIS data center that is planned to open 2 months before the TESIS launching at http://www.tesis.lebedev.ru

  11. ACTS (Advanced Communications Technology Satellite) Propagation Experiment: Preprocessing Software User's Manual

    Science.gov (United States)

    Crane, Robert K.; Wang, Xuhe; Westenhaver, David

    1996-01-01

    The preprocessing software manual describes the Actspp program originally developed to observe and diagnose Advanced Communications Technology Satellite (ACTS) propagation terminal/receiver problems. However, it has been quite useful for automating the preprocessing functions needed to convert the terminal output to useful attenuation estimates. Prior to having data acceptable for archival functions, the individual receiver system must be calibrated and the power level shifts caused by ranging tone modulation must be received. Actspp provides three output files: the daylog, the diurnal coefficient file, and the file that contains calibration information.

  12. SEU results from the Advanced Photovoltaic and Electronics Experiments (APEX) satellite

    Energy Technology Data Exchange (ETDEWEB)

    Mullen, E.G.; Ray, K.P. [Phillips Lab., Hanscom AFB, MA (United States); Koga, R. [Aerospace Corp., Los Angeles, CA (United States); Holeman, E.G.; Delorey, D.E. [Boston Coll., Newton, MA (United States). Inst. for Space Research

    1995-12-01

    The APEX satellite, launched in August of 1994, had a solid state data recorder (SSDR) as its onboard data storage system. The recorder contained 220 4Mbit X 1 Hitachi DRAMs of which 176 were routinely interrogated for SEUs and corrected with an EDAC code. Corrections were recorded in the spacecraft housekeeping files and are the basis of this study. The SEU rates and spatial locations are compared to in-situ particle measurements and to ground test results from devices from the same lot flown. The results show that properly designed SSDRs are a viable alternative to conventional tap recording systems for all orbits in near-Earth space.

  13. US plant and radiation dosimetry experiments flown on the Soviet satellite Cosmos 1129

    Science.gov (United States)

    Heinrich, M. R. (Editor); Souza, K. A. (Editor)

    1981-01-01

    Experiments included: 30 young male Wistar SPF rats used for wide range physiological studies; experiments with plants, fungi, insects, and mammalian tissue cultures; radiation physics experiments; a heat convection study; a rat embryology experiment in which an attempt was made to breed 2 male and 5 female rats during the flight; and fertile quail eggs used to determine the effects of spaceflight on avian embryogenesis. Specimens for US experiments were initially prepared at the recovery site or in Moscow and transferred to US laboratories for complete analyses. An overview of the mission focusing on preflight, on orbit, and postflight activities pertinent to the fourteen US experiments aboard Cosmos 1129 is presented.

  14. The Italian Radio Occultation experiment on-board the Indian OCEANSAT-2 satellite

    Science.gov (United States)

    Perona, G.; Rosa Team

    During the June 2007 the Indian satellite OCEANSAT-2 will be launched The Italian Space Agency ASI signed a Memorandum of Understandings with the Indian Space Research Organization ISRO in which it is agreed to put on-board the OCEANSAT-2 satellite the Italian GNSS receiver devoted to Radio Occultation ROSA - Radio Occultation Sounder of the Atmosphere In the framework of this mission this instrument can only be able to observe rising occultations the Radio Occultation antenna will be mounted on the aft-velocity direction collecting data both in Open-Loop and in Close-Loop modes These data will be downloaded to the Indian and the Italian receiving stations where they will be processed by the ROSA ground segment completely developed by Italian universities and research centres In particular this ground segment will be implemented at a first level in an integrated computing infrastructure installed in Matera and mirrored at Hyderbad in India and at a second level on a distributed software and hardware infrastructure This second infrastructure will perform the rapid and precise Orbit Determination and Prediction the bending and impact parameters profiles extraction the ionospheric correction and the stratospheric initialization the refractivity pressure temperature and humidity profile retrieval the value added services for meteorology climate and space weather applications by computing units of each research centre or university connected through a Web-based GRID computing infrastructure After a description of these two

  15. A Regional CO2 Observing System Simulation Experiment for the ASCENDS Satellite Mission

    Science.gov (United States)

    Wang, J. S.; Kawa, S. R.; Eluszkiewicz, J.; Baker, D. F.; Mountain, M.; Henderson, J.; Nehrkorn, T.; Zaccheo, T. S.

    2014-01-01

    Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions) generated by the WRF-STILT Lagrangian transport model in a regional Bayesian synthesis inversion. The regional Lagrangian framework is well suited to make use of ASCENDS observations to constrain fluxes at high resolution, in this case at 1 degree latitude x 1 degree longitude and weekly for North America. We consider random measurement errors only, modeled as a function of mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the 1 degree x 1 degree, weekly scale, the largest uncertainty reductions, on the order of 50 percent, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 micron candidate wavelength than for a 2.05 micron wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada). Uncertainty reductions at the annual, biome scale range from 40 percent to 75 percent across our four instrument design cases, and from 65 percent to 85 percent for the continent as a whole. Our uncertainty

  16. A regional CO2 observing system simulation experiment for the ASCENDS Satellite Mission

    Directory of Open Access Journals (Sweden)

    J. S. Wang

    2014-05-01

    Full Text Available Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions generated by the WRF-STILT Lagrangian transport model in a regional Bayesian synthesis inversion. The regional Lagrangian framework is well suited to make use of ASCENDS observations to constrain fluxes at high resolution, in this case at 1° latitude × 1° longitude and weekly for North America. We consider random measurement errors only, modeled as a function of mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the 1° × 1°, weekly scale, the largest uncertainty reductions, on the order of 50%, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 μm candidate wavelength than for a 2.05 μm wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada. Uncertainty reductions at the annual, biome scale range from ∼40% to ∼75% across our four instrument design cases, and from ∼65% to ∼85% for the continent as a whole. Our uncertainty reductions at various scales are

  17. Characteristics of vesicomyid clams and their environment at the Blake Ridge cold seep, South Carolina, USA

    Science.gov (United States)

    Heyl, Taylor P.; Gilhooly, William P.; Chambers, Randolph M.; Gilchrist, George W.; Macko, Stephen A.; Ruppel, Carolyn D.; Van Dover, Cindy L.

    2007-01-01

    Spatial distributions and patchiness of dominant megafaunal invertebrates in deep-sea seep environments may indicate heterogeneities in the flux of reduced chemical compounds. At the Blake Ridge seep off South Carolina, USA, the invertebrate assemblage includes dense populations of live vesicomyid clams (an undescribed species) as well as extensive clam shell beds (i.e. dead clams). In the present study, we characterized clam parameters (density, size-frequency distribution, reproductive condition) in relation to sulfur chemistry (sulfide and sulfate concentrations and isotopic compositions, pyrite and elemental sulfur concentrations) and other sedimentary metrics (grain size, organic content). For clams >5 mm, clam density was highest where the total dissolved sulfide concentration at 10 cm depth (ΣH2S10cm) was 0.4 to 1.1 mmol l–1; juvenile clams (2S10cm was lowest. Clams were reproductively capable across a broad range of ΣH2S10cm (0.1 to 6.4 mmol l–1), and females in the sampled populations displayed asynchronous gametogenesis. Sulfide concentrations in porewaters at the shell–sediment interface of cores from shell beds were high, 3.3 to 12.1 mmol l–1, compared to –1 sulfide concentrations at the clam–sediment interface in live clam beds. Concentration profiles for sulfide and sulfate in shell beds were typical of those expected where there is active microbial sulfate reduction. In clam beds, profiles of sulfide and sulfate concentrations were also consistent with rapid uptake of sulfide by the clams. Sulfate in shell beds was systematically enriched in 34S relative to that in clam beds due to microbial fractionation during sulfate reduction, but in clam beds, sulfate δ34S matched that of seawater (~20‰). Residual sulfide values in clam and shell beds were correspondingly depleted in 34S. Based on porewater sulfide concentrations in shell beds at the time of sampling, we suggest that clam mortality may have been due to an abrupt increase in

  18. C and L band transionospheric scintillation experiment - Some results for applications to satellite radio systems

    Science.gov (United States)

    Banerjee, P. K.; Dabas, R. S.; Reddy, B. M.

    1992-12-01

    The signal statistics of some scintillation events at the C/L bands are estimated for the high solar activity period of solar cycle 22 at a low-latitude station in the Indian zone. In addition to the morphology at 4 Ghz, data on signal statistics such as the cumulative amplitude distribution function, fade rate distribution, and signal reliability for different message lengths for some events of scintillations, both at C and L band, are presented. The theoretical Nakagami m distribution is found to be the best for describing various levels of fade. Autocorrelation and power-spectrum analysis are used to estimate average fade rates and ground correlation distances. Performance evaluation of satellite earth terminals using small antennas is carried out to show the vulnerability of the system in the hostile ionospheric environment, notwithstanding the advanced modulation systems being employed.

  19. A study of Asian dust plumes using satellite, surface, and aircraft measurements during the INTEX-B field experiment

    Science.gov (United States)

    Logan, Timothy; Xi, Baike; Dong, Xiquan; Obrecht, Rebecca; Li, Zhanqing; Cribb, Maureen

    2010-04-01

    Asian dust events occur frequently during the boreal spring season. Their optical properties have been analyzed by using a combination of source region (ground-based and satellite) and remote Pacific Ocean (aircraft) measurements during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B) field campaign which lasted from 7 April to 15 May 2006. A strong dust event originating from the Gobi Desert and passing over the Xianghe surface site on 17 April 2006 has been extensively analyzed. The surface averaged aerosol optical depth (AOD) values increased from 0.17 (clear sky) to 4.0 (strong dust), and the Angström exponent (α) dropped from 1.26 (clear sky) to below 0.1. Its total downwelling SW flux over the Xianghe site (thousands of kilometers away from the dust source region) is only 46% of the clear-sky value with almost no direct transmission and nearly double the diffuse SW clear-sky value. This event was also captured 6 days later by satellite observations as well as the UND/NASA DC-8 aircraft over the eastern Pacific Ocean. The DC-8 measurements in the remote Pacific region further classified the plumes into dust dominant, pollution dominant, and a mixture of dust and pollution events. HYSPLIT backward trajectories not only verified the origins of each case we selected but also showed (1) two possible origins for the dust: the Gobi and Taklimakan deserts; and (2) pollution: urban areas in eastern China, Japan, and other industrialized cities east of the two deserts. Based on the averaged satellite retrieved AOD data (0.5° × 0.5° grid box), declining AOD values with respect to longitude demonstrated the evolution of the transpacific transport pathway of Asian dust and pollution over the period of the field campaign.

  20. CRRES/SPACERAD (Combined Release and Radiation Effects Satellite/Space Radiation Effects Program) Experiment Descriptions.

    Science.gov (United States)

    1985-01-24

    A., Hertzberg, E., Battel, S.J., Altwegg-Von Burg, K., and Balsiger, H. (1984) AMPTE/CCE hot plasma composition experiment (HPCE), submitted to IEEE...CCE hot plasma composition experiment (HPCE), submitted to IEEE Trans. Remote Sensing. 151 iL Contents 1. Scientific Objectives 153 2. Applications 154

  1. 50 CFR 17.45 - Special rules-snails and clams. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-snails and clams. 17.45 Section 17.45 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—snails and clams....

  2. Remote Synchronization Experiments for Quasi-Zenith Satellite System Using Multiple Navigation Signals as Feedback Control

    Directory of Open Access Journals (Sweden)

    Toshiaki Iwata

    2011-01-01

    Full Text Available The remote synchronization system for the onboard crystal oscillator (RESSOX is a remote control method that permits synchronization between a ground station atomic clock and Japanese quasi-zenith satellite system (QZSS crystal oscillators. To realize the RESSOX of the QZSS, the utilization of navigation signals of QZSS for feedback control is an important issue. Since QZSS transmits seven navigation signals (L1C/A, L1CP, L1CD, L2CM, L2CL, L5Q, and L5I, all combinations of these signals should be evaluated. First, the RESSOX algorithm will be introduced. Next, experimental performance will be demonstrated. If only a single signal is available, ionospheric delay should be input from external measurements. If multiple frequency signals are available, any combination, except for L2 and L5, gives good performance with synchronization error being within two nanoseconds that of RESSOX. The combination of L1CD and L5Q gives the best synchronization performance (synchronization error within 1.14 ns. Finally, in the discussion, comparisons of long-duration performance, computer simulation, and sampling number used in feedback control are considered. Although experimental results do not correspond to the simulation results, the tendencies are similar. For the overlapping Allan deviation of long duration, the stability of 1.23×10−14 at 100,160 s is obtained.

  3. The PAMELA experiment on satellite and its capability in cosmic rays measurements

    CERN Document Server

    Adriani, O; Barbarino, G C; Barbier, L M; Bartalucci, S; Bazilevskaja, G; Bellotti, R; Bertazzoni, S; Bidoli, V; Boezio, M; Bogomolov, E A; Bonechi, L; Bonvicini, V; Boscherini, M; Bravar, U; Cafagna, F; Campana, D; Carlson, Per J; Casolino, M; Castellano, M; Castellini, G; Christian, E R; Ciacio, F; Circella, M; D'Alessandro, R; De Marzo, C N; De Pascale, M P; Finetti, N; Furano, G; Gabbanini, A; Galper, A M; Giglietto, N; Grandi, M; Grigorieva, A; Guarino, F; Hof, M; Koldashov, S V; Korotkov, M G; Krizmanic, J F; Krutkov, S; Lund, J; Marangelli, B; Marino, L; Menn, W; Mikhailov, V V; Mirizzi, N; Mitchell, J W; Mocchiutti, E; Moiseev, A A; Morselli, A; Mukhametshin, R; Ormes, J F; Osteria, G; Ozerov, J V; Papini, P; Pearce, M; Perego, A; Piccardi, S; Picozza, P; Ricci, M; Salsano, A; Schiavon, Paolo; Scian, G; Simon, M; Sparvoli, R; Spataro, B; Spillantini, P; Spinelli, P; Stephens, S A; Stochaj, S J; Stozhkov, Yu I; Straulino, S; Streitmatter, R E; Taccetti, F; Tesi, M; Vacchi, A; Vannuccini, E; Vasiljev, G; Vignoli, V; Voronov, S A; Yurkin, Y; Zampa, G; Zampa, N

    2002-01-01

    The PAMELA equipment will be assembled in 2001 and installed on board the Russian satellite Resurs. PAMELA is conceived mainly to study the antiproton and positron fluxes in cosmic rays up to high energy (190 GeV for p-bar and 270 GeV for e sup +) and to search antinuclei, up to 30 GeV/n, with a sensitivity of 10 sup - sup 7 in the He-bar/He ratio. The PAMELA telescope consists of: a magnetic spectrometer made up of a permanent magnet system equipped with double sided microstrip silicon detectors; a transition radiation detector made up of active layers of proportional straw tubes interleaved with carbon fibre radiators; and a silicon-tungsten imaging calorimeter made up of layers of tungsten absorbers and silicon detector planes. A time-of-flight system and anti-coincidence counters complete the PAMELA equipment. In the past years, tests have been done on each subdetector of PAMELA; the main results are presented and their implications on the anti-particles identification capability in cosmic rays are discus...

  4. The PAMELA experiment on satellite and its capability in cosmic rays measurements

    Energy Technology Data Exchange (ETDEWEB)

    Adriani, O.; Ambriola, M.; Barbarino, G.; Barbier, L.M.; Bartalucci, S.; Bazilevskaja, G.; Bellotti, R.; Bertazzoni, S.; Bidoli, V.; Boezio, M.; Bogomolov, E.; Bonechi, L.; Bonvicini, V.; Boscherini, M.; Bravar, U.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellano, M.; Castellini, G.; Christian, E.R.; Ciacio, F.; Circella, M.; D' Alessandro, R.; De Marzo, C.N.; De Pascale, M.P.; Finetti, N.; Furano, G.; Gabbanini, A.; Galper, A.M.; Giglietto, N.; Grandi, M.; Grigorjeva, A.; Guarino, F.; Hof, M.; Koldashov, S.V.; Korotkov, M.G.; Krizmanic, J.F.; Krutkov, S.; Lund, J.; Marangelli, B.; Marino, L.; Menn, W.; Mikhailov, V.V.; Mirizzi, N.; Mitchell, J.W.; Mocchiutti, E.; Moiseev, A.A.; Morselli, A.; Mukhametshin, R.; Ormes, J.F.; Osteria, G.; Ozerov, J.V.; Papini, P.; Pearce, M.; Perego, A.; Piccardi, S.; Picozza, P.; Ricci, M.; Salsano, A.; Schiavon, P.; Scian, G.; Simon, M.; Sparvoli, R.; Spataro, B.; Spillantini, P.; Spinelli, P.; Stephens, S.A.; Stochaj, S.J.; Stozhkov, Y.; Straulino, S. E-mail: straulino@fi.infi.it; Streitmatter, R.E.; Taccetti, F.; Tesi, M.; Vacchi, A.; Vannuccini, E.; Vasiljev, G.; Vignoli, V.; Voronov, S.A.; Yurkin, Y.; Zampa, G.; Zampa, N

    2002-02-01

    The PAMELA equipment will be assembled in 2001 and installed on board the Russian satellite Resurs. PAMELA is conceived mainly to study the antiproton and positron fluxes in cosmic rays up to high energy (190 GeV for p-bar and 270 GeV for e{sup +}) and to search antinuclei, up to 30 GeV/n, with a sensitivity of 10{sup -7} in the He-bar/He ratio. The PAMELA telescope consists of: a magnetic spectrometer made up of a permanent magnet system equipped with double sided microstrip silicon detectors; a transition radiation detector made up of active layers of proportional straw tubes interleaved with carbon fibre radiators; and a silicon-tungsten imaging calorimeter made up of layers of tungsten absorbers and silicon detector planes. A time-of-flight system and anti-coincidence counters complete the PAMELA equipment. In the past years, tests have been done on each subdetector of PAMELA; the main results are presented and their implications on the anti-particles identification capability in cosmic rays are discussed here.

  5. DSN radio science system description and requirements. [for satellite radio astronomy experiments

    Science.gov (United States)

    Mulhall, B. D. L.

    1977-01-01

    The data system created to collect the functions performed by the Deep Space Network in support of spacecraft radio science experiments is described. Some of the major functional requirements presently being considered for the system are delineated.

  6. DSN radio science system description and requirements. [for satellite radio astronomy experiments

    Science.gov (United States)

    Mulhall, B. D. L.

    1977-01-01

    The data system created to collect the functions performed by the Deep Space Network in support of spacecraft radio science experiments is described. Some of the major functional requirements presently being considered for the system are delineated.

  7. Microplastic Ingestion by Wild and Cultured Manila Clams (Venerupis philippinarum) from Baynes Sound, British Columbia.

    Science.gov (United States)

    Davidson, Katie; Dudas, Sarah E

    2016-08-01

    Microplastics, plastic particles Baynes Sound, British Columbia were chosen to examine the microplastic concentrations in wild and cultured Manila clams. Microplastics were isolated using a nitric acid digestion technique and enumerated from 54 clams (27 farmed and 27 non-farmed). Qualitative attributes, such as colour and microplastic type (fiber, fragment, or film) also were recorded. There was no significant difference (F = 1.29; df = 1,4; P = 0.289) between microplastic concentrations in cultured and wild clams. Microplastic concentrations ranged from 0.07 to 5.47 particles/g (from reference beach and shellfish farm clams, respectively). Fibers were the dominant microplastic (90 %); colourless and dark gray fibers were the most common colours observed (36 and 26 %, respectively). Although this indicates that microplastics are definitely present in seafood consumed by humans, shellfish aquaculture operations do not appear to be increasing microplastic concentrations in farmed clams in this region.

  8. Mercury accumulation in the clam, Galatea paradoxa (Born 1778) at the Volta estuary, Ghana.

    Science.gov (United States)

    Obirikorang, K A; Amisah, S; Adjei-Boateng, D; Madkour, H A; Otchere, F A

    2010-11-01

    The concentration of mercury in the tissues of the clam, Galatea paradoxa at in the Volta estuary, Ghana, were analysed over an 18-month period, from March 2008 to August 2009. The concentrations were well below the International Human Consumption Advisory Limit of THg (0.5 μg/g wet weight). The concentrations in the tissues of the different clam size classes were between 6 and 18 times lower than the WHO Safety Reference Standard. Variation in the mean mercury concentration in the different clam size classes was not significant (p > 0.05) for clams from Aveglo but were highly significant (p < 0.0001) for clams from Ada, indicating a possible effect of size on accumulation. G. paradoxa is therefore suitable for human consumption based on the WHO Safety Reference Standards.

  9. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  10. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  11. Assessment of clam ruditapes philippinarum as Heavy metal bioindicators using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoli; Zhang, Linbao; You, Liping [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Cong, Ming; Wang, Qing; Li, Fei; Li, Lianzhen; Zhao, Jianmin; Li, Chenghua; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China)

    2011-08-15

    There are mainly distributed three pedigrees (White, Liangdao Red, and Zebra) of Manila clam Ruditapes philippinarum in Yantai population along the Bohai marine and coast. However, the biological differences to environmental stressors have been ignored in toxicology studies, which could lead to the distortion of biological interpretations of toxicological effects induced by environmental contaminants. In this study, we applied a system biology approach, metabolomics to compare the metabolic profiles in digestive gland from three pedigrees of clam and characterize and compare the metabolic responses induced by mercury in clam digestive gland tissues to determine a sensitive pedigree of clam as a preferable bioindicator for metal pollution monitoring and toxicology research. The most abundant metabolites, respectively, included branched-chain amino acids, alanine, and arginine in White samples, glutamate, dimethylglycine, and glycine in Zebra clams and acetylcholine, betaine, glucose, and glycogen in Liangdao Red clams. After 48 h exposure of 20 {mu}g L{sup -1} Hg{sup 2+}, the metabolic profiles from the three pedigrees of clams showed differentially significant changes in alanine, glutamate, succinate, taurine, hypotaurine, glycine, arginine, glucose, etc. Our findings indicate the toxicological effects of mercury exposure in Manila clams including the neurotoxicity, disturbances in energetic metabolisms and osmoregulation in the digestive glands and suggest that Liangdao Red pedigree of clam could be a preferable bioindicator for the metal pollution monitoring based on the more sensitive classes of metabolic changes from digestive glands compared with other two (White and Zebra) pedigrees of clams. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Biodeposition, respiration, and excretion rates of an introduced clam Mercenaria mercenaria in ponds with implications for potential competition with the native clam Meretrix meretrix in Shuangtaizi estuary, China

    Science.gov (United States)

    Zhang, Anguo; Yuan, Xiutang; Hou, Wenjiu; Li, Xiaodong; Zhao, Kai; Chen, Weixin; Su, Xiurong

    2016-05-01

    This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06-0.37 g/ (ind.·d), and the respiration rates were 0.31-14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18-36.70 and 1.44-14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem.

  13. US monkey and rat experiments flown on the Soviet Satellite Cosmos 1514

    Science.gov (United States)

    Mains, R. C. (Editor); Gomersall, E. W. (Editor)

    1986-01-01

    On December 14, 1983, the U.S.S.R. launched Cosmos 1514, an unmanned spacecraft carrying biological and radiation physics experiments from nine countries, including five from the United States. This was the fourth flight with U.S. experiments aboard one of the Soviet unmanned spacecraft. The Cosmos 1514 flight was limited to five days duration because it was the first nonhuman primate flight. Cosmos 1514 marked a significant departure from earlier flights both in terms of Soviet goals and the degree of cooperation between the U.S.S.R. and the United States. This flight included more than 60 experiments on fish, crawfish eggs, plants and seeds, 10 Wistar pregnant rats, and 2 young adult rhesus monkeys as human surrogates. United States specialist participated in postflight data transfer and specimen transfer, and conducted rat neonatal behavioral studies. An overview of the mission is presented focusing on preflight, on-orbit, and postflight activites pertinent to the five U.S. experiments aboard Cosmos.

  14. Relative humidity distribution from SAPHIR experiment on board Megha-Tropiques satellite mission: Comparison with global radiosonde and other satellite and reanalysis data sets

    Science.gov (United States)

    Venkat Ratnam, M.; Basha, Ghouse; Krishna Murthy, B. V.; Jayaraman, A.

    2013-09-01

    For better understanding the life cycle of the convective systems and their interactions with the environment, a joint Indo-French satellite mission named Megha-Tropiques has been launched in October 2011 in a low-inclination (20°) orbit. In the present study, we show the first results on the comparison of relative humidity (RH) obtained using a six-channel microwave sounder, covering from surface to 100 hPa, from one of the payloads SAPHIR (Sounder for Atmospheric Profiling of Humidity in the Inter-tropical Regions). The RH observations from SAPHIR illustrated the numerous scales of variability in the atmosphere both vertically and horizontally. As a part of its validation, we compare SAPHIR RH with simultaneous observations from a network of radiosondes distributed across the world (±30° latitude), other satellites (Atmospheric Infrared Sounder, Infrared Atmospheric Sounder Interferometer, Constellation Observation System for Meteorology Ionosphere and Climate (COSMIC)), and various reanalysis (National Center for Environmental Prediction (NCEP), European Center for Medium-Range Weather Forecasts reanalysis (ERA)-Interim, Modern-Era Retrospective Analysis for Research and Application (MERRA)) products. Being at a low inclination, SAPHIR is able to show better global coverage when compared to any other existing satellites in the tropical region where some important weather processes take place. A very good correlation is noticed with the RH obtained from a global radiosonde network particularly in the altitude range corresponding to 850-250 hPa, thus providing a valuable data set for investigating the convective processes. In the case of satellite data sets, SAPHIR RH is well comparable with COSMIC RH. Among the reanalysis products, NCEP shows less difference with SAPHIR followed by ERA-Interim, and the MERRA products show large differences in the middle and upper troposphere.

  15. Microbiological responses to depuration and transport of native and exotic clams at optimal and stressful temperatures.

    Science.gov (United States)

    Anacleto, Patrícia; Maulvault, Ana Luísa; Chaguri, Milena; Pedro, Sónia; Nunes, Maria Leonor; Rosa, Rui; Marques, António

    2013-12-01

    The microbiological responses of two bivalves species from Tagus estuary, Venerupis pullastra (native clam) and Ruditapes philippinarum (exotic clam) were investigated during 48 h of depuration and subsequent simulated transport in semi-dry conditions at two temperatures (4 and 22 °C) until reaching 50% lethal time (LT50). Regardless of temperature and species, the maintenance of clams in water for 48 h (depuration period) did not affect LT50 during transport. R. philippinarum showed higher survival rates than V. pullastra, always reaching LT50 later, especially at 4 °C. Significant differences between clams' species were found in almost all microbiological parameters. This can be related with clams' biological activity and habitat environmental conditions since both clams do not coexist in Tagus estuary. Depuration was efficient to reduce the bacterial load, particularly Escherichia coli, but not efficient to remove Vibrio spp. In both species, the growth of Vibrio spp. was inhibited at 4 °C, whereas exponential growth occurred at 22 °C. Total viable counts significantly increased in most treatments, while E. coli counts significantly decreased to undetected levels, except for non-depurated R. philippinarum simulated transported at 4 °C. Thus, this study highlights the importance of clams depuration for at least 24 h in polluted estuarine areas, followed by transport at low temperatures (4 °C). Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Metal concentrations in sediments and clams in four Moroccan estuaries.

    Science.gov (United States)

    Cheggour, M; Chafik, A; Fisher, N S; Benbrahim, S

    2005-03-01

    Metals (Cd, Cu, Ni, Zn, Mn and Fe) were analyzed seasonally over three years in sediments and in tissues of the clam Scrobicularia plana in four Moroccan Atlantic estuaries: Loukkos, Sebou, Bou Regreg and Oum er Rbia. Of these metals, Cd was at the lowest concentrations in sediment. Concentrations of Cu, Zn, and to a lesser extent Ni, in sediments suggest greater contamination in Sebou and Bou Regreg than in the other estuaries. The fluctuations of Mn and Fe concentrations in the fine surface sediments reflect their continental origin and show seasonal variations that indicate soil run-off following rain events. Concentrations of Cu, Zn, and especially Ni in clam tissues in these estuaries were generally higher than in some other common bioindicator bivalve species. The seasonal variations in S. plana's tissue metal concentrations are linked to patterns of reproductive activity for all metals except Cd and possibly Zn, whose tissue concentrations may be regulated. Mn and Fe concentrations in S. plana were positively correlated to sediment levels of these metals.

  17. The neutral atmosphere temperature experiment. [for thermospheric nitrogen measurement on AEROS satellite

    Science.gov (United States)

    Spencer, N. W.; Pelz, D. T.; Niemann, H. B.; Carignan, G. R.; Caldwell, J. R.

    1974-01-01

    The AEROS Neutral Atmosphere Temperature Experiment (NATE) is designed to measure the kinetic temperature of molecular nitrogen in the thermosphere. A quadrupole mass spectrometer tuned to N2 measures the N2 density variation in a small spherical antechamber having a knife-edged orifice which is exposed to the atmosphere at the outer surface of the spacecraft. The changing density of N2 due to the spinning motion of the spacecraft permits determination of the velocity distribution of the N2 from which the temperature is calculated. An alternate mode of operation of the instrument allows measurement of the other gases in the atmosphere as well as N2 permitting determination of the neutral particle composition of the atmosphere.

  18. [THE CONTENT OF MERCURY IN SEDIMENTS AND THE CLAMS UNIO PICTORUM FROM THE URAL RIVER].

    Science.gov (United States)

    Solovykh, G N; Osinkina, V V; Vereshchagin, N N; Belomestnova, V G; Vodyanitskaya, O V; Kamaukhova, I V

    2015-01-01

    There was investigated the mercury total content in bottom sediments and some bodies of clams from the area of the middle reach of the Ural river near the Orenburg city. In bottom sediments there was revealed an excess of the ecological standard for mercury. There was noted the uneven distribution of toxicant in bodies of clams: the maximal contents was detected in hepatopancreas, minimal--in "foot", that apparently is determined by the unequal metabolitic activity of these tissues. The highest concentration of mercury in the tissues of clams was noted at the station "Ural river above the camp" Dubki".

  19. Supernova / Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

    CERN Document Server

    Aldering, G; Amanullah, R; Annis, J; Astier, Pierre; Baltay, C; Barrelet, E; Basa, S; Bebek, C; Bergström, L; Bernstein, G; Bester, M; Bigelow, B; Blandford, R D; Bohlin, R; Bonissent, A; Bower, C; Brown, M; Campbell, M; Carithers, W; Commins, Eugene D; Craig, W; Day, C; De Jongh, F; Deustua, S; Diehl, T; Dodelson, S; Ealet, A; Ellis, R; Emmet, W; Fouchez, D; Frieman, J A; Fruchter, A; Gerdes, D; Gladney, L; Goldhaber, G; Goobar, A; Groom, D; Heetderks, H; Hoff, M; Holland, S; Huffer, M; Hui, L; Huterer, D; Jain, B; Jelinsky, P N; Karcher, A; Kent, S; Kahn, S; Kim, A; Kolbe, W; Krieger, B; Kushner, G; Kuznetsova, N; Lafever, R; Lamoureux, J; Lampton, M; Lefèvre, O; Levi, M; Limon, P; Lin, H; Linder, E; Loken, S; Lorenzon, W; Malina, R; Marriner, J P; Marshall, P; Massey, R; Mazure, A; McKay, T; McKee, S; Miquel, R; Morgan, N; Mortsell, E; Mostek, N; Mufson, S; Musser, J; Nugent, P; Olus, H; Pain, R; Palaio, N; Pankow, D; Peoples, John; Perlmutter, S; Prieto, E; Rabinowitz, D; Réfrégier, A; Rhodes, J; Roe, N; Rusin, D; Scarpine, V; Schubnell, M; Sholl, M; Smadja, G; Smith, R M; Smoot, George F; Snyder, J; Spadafora, A; Stebbins, A; Stoughton, C; Szymkowiak, A; Tarle, G; Taylor, K; Tilquin, A; Tomasch, A; Tucker, D; Vincent, D; Von der Lippe, H; Walder, J P; Wang, G; Wester, W

    2004-01-01

    The Supernova / Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled measurements. We describe a self-consistent reference mission design for building a Type Ia supernova Hubble diagram and for performing a wide-area weak gravitational lensing study. A 2-m wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The SNAP mission will obtain high-signal-to-noise calibrated light-curves and spectra for several thousand supernovae at redshifts between z=0.1 and 1.7. A wide-field survey covering one thousand square degrees resolves ~100 galaxies per square arcminute. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and ...

  20. Measuring the Value of Earth Observation Information with the Gravity Research and Climate Experiment (GRACE) Satellite

    Science.gov (United States)

    Bernknopf, R.; Kuwayama, Y.; Brookshire, D.; Macauley, M.; Zaitchik, B.; Pesko, S.; Vail, P.

    2014-12-01

    Determining how much to invest in earth observation technology depends in part on the value of information (VOI) that can be derived from the observations. We design a framework and then evaluate the value-in-use of the NASA Gravity Research and Climate Experiment (GRACE) for regional water use and reliability in the presence of drought. As a technology that allows measurement of water storage, the GRACE Data Assimilation System (DAS) provides information that is qualitatively different from that generated by other water data sources. It provides a global, reproducible grid of changes in surface and subsurface water resources on a frequent and regular basis. Major damages from recent events such as the 2012 Midwest drought and the ongoing drought in California motivate the need to understand the VOI from remotely sensed data such as that derived from GRACE DAS. Our conceptual framework models a dynamic risk management problem in agriculture. We base the framework on information from stakeholders and subject experts. The economic case for GRACE DAS involves providing better water availability information. In the model, individuals have a "willingness to pay" (wtp) for GRACE DAS - essentially, wtp is an expression of savings in reduced agricultural input costs and for costs that are influenced by regional policy decisions. Our hypothesis is that improvements in decision making can be achieved with GRACE DAS measurements of water storage relative to data collected from groundwater monitoring wells and soil moisture monitors that would be relied on in the absence of GRACE DAS. The VOI is estimated as a comparison of outcomes. The California wine grape industry has features that allow it to be a good case study and a basis for extrapolation to other economic sectors. We model water use in this sector as a sequential decision highlighting the attributes of GRACE DAS input as information for within-season production decisions as well as for longer-term water reliability.

  1. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  2. Long Range River Discharge Forecasting Using the Gravity Recovery and Climate Experiment (GRACE) Satellite to Predict Conditions for Endemic Cholera

    Science.gov (United States)

    Jutla, A.; Akanda, A. S.; Colwell, R. R.

    2014-12-01

    Prediction of conditions of an impending disease outbreak remains a challenge but is achievable if the associated and appropriate large scale hydroclimatic process can be estimated in advance. Outbreaks of diarrheal diseases such as cholera, are related to episodic seasonal variability in river discharge in the regions where water and sanitation infrastructure are inadequate and insufficient. However, forecasting river discharge, few months in advance, remains elusive where cholera outbreaks are frequent, probably due to non-availability of geophysical data as well as transboundary water stresses. Here, we show that satellite derived water storage from Gravity Recovery and Climate Experiment Forecasting (GRACE) sensors can provide reliable estimates on river discharge atleast two months in advance over regional scales. Bayesian regression models predicted flooding and drought conditions, a prerequisite for cholera outbreaks, in Bengal Delta with an overall accuracy of 70% for upto 60 days in advance without using any other ancillary ground based data. Forecasting of river discharge will have significant impacts on planning and designing intervention strategies for potential cholera outbreaks in the coastal regions where the disease remain endemic and often fatal.

  3. Supernova/Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

    Energy Technology Data Exchange (ETDEWEB)

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, E.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, C.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; Craig, W.; Day, C.; DeJongh, F.; Deustua, S.; Diehl, T.; Dodelson, S.; Ealet, A.; Ellis, R.; Emmet, W.; Fouchez, D.; Frieman, J.; Fruchter, A.; Gerdes, D.; Gladney, L.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Hoff, M.; Holland, S.; Huffer, M.; Hui, L.; Huterer, D.; Jain, B.; Jelinsky, P.; Karcher, A.; Kent, S.; Kahn, S.; Kim, A.; Kolbe, W.; Krieger, B.; Kushner, G.; Kuznetsova, N.; Lafever, R.; Lamoureux, J.; Lampton, M.; Le Fevre, O.; Levi, M.; Limon, P.; Lin, H.; Linder, E.; Loken, S.; Lorenzon, W.; Malina, R.; Marriner, J.; Marshall, P.; Massey, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Peoples, J.; Perlmutter, S.; Prieto, E.; Rabinowitz, D.; Refregier, A.; Rhodes, J.; Roe, N.; Rusin, D.; Scarpine, V.; Schubnell, M.; Sholl, M.; Samdja, G.; Smith, R.M.; Smoot, G.; Snyder, J.; Spadafora, A.; Stebbine, A.; Stoughton, C.; Szymkowiak, A.; Tarle, G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Tucker, D.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.; Wester, W.

    2004-05-12

    The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universes expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and southern fields resolves {approx} 100 galaxies per square arcminute, or a total of more than 300 million galaxies. With the PSF stability afforded by a space observatory, SNAP will provide precise and accurate measurements of gravitational lensing. The high-quality data available in space, combined with the large sample of supernovae, will enable stringent control of systematic uncertainties. The resulting data set will be used to determine the energy density of dark energy and parameters that describe its dynamical behavior. The data also provide a direct test of theoretical models for the dark energy

  4. Supernova / Acceleration Probe: a Satellite Experiment to Study the Nature of the Dark Energy

    Energy Technology Data Exchange (ETDEWEB)

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; /LBL, Berkeley /SLAC /Stockholm U. /Fermilab /Paris U., VI-VII /Yale U.

    2005-08-15

    The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and southern fields resolves {approx} 100 galaxies per square arcminute, or a total of more than 300 million galaxies. With the PSF stability afforded by a space observatory, SNAP will provide precise and accurate measurements of gravitational lensing. The high-quality data available in space, combined with the large sample of supernovae, will enable stringent control of systematic uncertainties. The resulting data set will be used to determine the energy density of dark energy and parameters that describe its dynamical behavior. The data also provide a direct test of theoretical models for the dark

  5. Complementing the ground-based CMB-S4 experiment on large scales with the PIXIE satellite

    Science.gov (United States)

    Calabrese, Erminia; Alonso, David; Dunkley, Jo

    2017-03-01

    We present forecasts for cosmological parameters from future cosmic microwave background (CMB) data measured by the stage-4 (S4) generation of ground-based experiments in combination with large-scale anisotropy data from the PIXIE satellite. We demonstrate the complementarity of the two experiments and focus on science targets that benefit from their combination. We show that a cosmic-variance-limited measurement of the optical depth to reionization provided by PIXIE, with error σ (τ )=0.002 , is vital for enabling a 5 σ detection of the sum of the neutrino masses when combined with a CMB-S4 lensing measurement and with lower-redshift constraints on the growth of structure and the distance-redshift relation. Parameters characterizing the epoch of reionization will also be tightly constrained; PIXIE's τ constraint converts into σ (zre)=0.2 for the mean time of reionization, and a kinematic Sunyaev-Zel'dovich measurement from S4 gives σ (Δ zre)=0.03 for the duration of reionization. Both PIXIE and S4 will put strong constraints on primordial tensor fluctuations, vital for testing early-Universe models, and will do so at distinct angular scales. We forecast σ (r )≈5 ×10-4 for a signal with a tensor-to-scalar ratio r =10-3, after accounting for diffuse foreground removal and delensing. The wide and dense frequency coverage of PIXIE results in an expected foreground-degradation factor on r of only ≈25 %. By measuring large and small scales PIXIE and S4 will together better limit the energy injection at recombination from dark matter annihilation, with pannmeasured from the damping tail with S4 will be best constrained by polarization, which has the advantage of minimal contamination from extragalactic emission.

  6. Biological satellite Kosmos-936

    Science.gov (United States)

    Vedeshin, L. A.

    1978-01-01

    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  7. Population Dynamics of the Giant Clam, Tridacna maxima, at Rose Atoll

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There is a paucity of knowledge on the population dynamics of the giant clams of the family Tridacnidae. Such information on population dynamics is necessary for...

  8. Environmental context and trophic trait plasticity in a key species, the tellinid clam Macoma balthica L

    DEFF Research Database (Denmark)

    Törnroos, Anna; Nordström, M. C.; Aarnio, K.;

    2015-01-01

    showing differing isotopic signatures from clams at their original habitat, over time mirroring the changes in clams in the site to which they were transferred. The shift in carbon and nitrogen stable isotopes of the clams provides insights into the context-dependent intraspecific feeding plasticity......Species show varying levels of plasticity regarding morphology, physiology and behaviour in relation to their immediate environment, and several trait characteristics are habitat-dependent. Determining when and how the environmental context changes trait expression is of key importance...... food uptake by using stable isotope signatures (delta C-13 and delta N-15). We transplanted individuals between and within two shallow bays differing in exposure (exposed sheltered) and sediment characteristics. Our results show that isotope signatures of clams differed between the two habitats...

  9. Fisheries ecology: hunger for shark fin soup drives clam chowder off the menu.

    Science.gov (United States)

    Brierley, Andrew S

    2007-07-17

    Removal by fishing of large sharks has reduced predation-pressure on shark prey and, via a trophic cascade, caused clam populations to crash. This indirect response illustrates why fisheries should be managed in a whole-ecosystem context.

  10. Geographic distribution of mercury in asiatic clams, Corbicuia plumihea, from the North Fork Holston River, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A study was conducted quantifying mercury concentrations in the Asiatic clam, Corbicula fluminea, from the North Fork Holston River, Virginia. The purpose of this...

  11. Gametogenic development and spawning of the mud clam, Polymesoda erosa (Solander, 1876) at Chorao Island, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Clemente, S.; Ingole, B.S.

    in the adjacent estuarine water suggests that gametogenesis in mud clam is directly related to the phytoplankton production. The condition index (CI), which is generally used to characterize the physiological activity of organisms, varied from 1.9 in September...

  12. Contaminant assessment of fish, rangia clams, and sediments in the Lower Pamlico River, North Carolina

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Samples of sediment, rangia clams (Rangia cuneata), gizzard shad (Dorosoma cepedianum), and longnose gar (Lepisosteus osseus) were collected from five sites in the...

  13. Biodiesel Production from Castor Oil by Using Calcium Oxide Derived from Mud Clam Shell

    Directory of Open Access Journals (Sweden)

    S. Ismail

    2016-01-01

    Full Text Available The catalytic potential of calcium oxide synthesized from mud clam shell as a heterogeneous catalyst for biodiesel production was studied. The mud clam shell calcium oxide was characterized using particle size analyzer, Fourier transform infrared spectroscopy, scanning electron microscopy, and BET gas sorption analyzer. The catalyst performance of mud clam shell calcium oxide was studied in the transesterification of castor oil as biodiesel. Catalyst characterization and transesterification study results of synthesized catalyst proved the efficiency of the natural derived catalyst for biodiesel production. A highest biodiesel yield of 96.7% was obtained at optimal parameters such as 1 : 14 oil-to-methanol molar ratio, 3% w/w catalyst concentration, 60°C reaction temperature, and 2-hour reaction time. Catalyst reusability test shows that the synthesized calcium oxide from mud clam shell is reusable up to 5 times.

  14. The wedge clam Donax serra, popularly known as the white sand ...

    African Journals Online (AJOL)

    spamer

    sandy beach community (Brown and Mclachlan 1990) and, as ... disturbance of the sediment through clam harvesting activities ...... composition of Donax serra in the East Cape. ... of shore birds on sandy beaches in the Eastern Cape, South.

  15. Addressing Sustainability of Clam Farming in the Venice Lagoon

    Directory of Open Access Journals (Sweden)

    Donata Melaku Canu

    2011-09-01

    According to the System Approach Framework (SAF, based on previous studies and stakeholder interactions, we developed a model integrating ecological, social, and economic (ESE aspects. We chose the aspects necessary to represent the essential dynamics of major ecological, social, and economic clam farming system components to project the consequences of implementing alternative management policies and to address the ecological and social carrying capacity. Results of the simulations suggest that a properly managed farming system can sustain an acceptable income and support the local community, while reducing negative environmental impacts, social conflicts, and consumer health risks and improving system resilience. The results highlight the importance of an interdisciplinary, participatory, and adaptive approach in planning the management of this important renewable resource.

  16. Immune- and Pollution-mediated DNA Damage in Two Wild Mya arenaria Clam Populations

    OpenAIRE

    François Gagné; M. Laura Martín-Díaz; Christian Blaise

    2009-01-01

    In aquatic environments, genotoxicity results from the effects of pollution combined with the inflammatory response triggered by the immune system. Indeed, the production of nitrosylated DNA and proteins are though to arise from the production of peroxinitrite during phagocytosis and inflammation. The purpose of this study was to examine new DNA biomarkers that differentiate between immune- and pollution-mediated genotoxicity in wild clam populations. Intertidal clam populations were sampled ...

  17. Ionic and Amino Acid Regulation in Hard Clam (Meretrix lusoria in Response to Salinity Challenges

    Directory of Open Access Journals (Sweden)

    Chia-Hao Lin

    2016-08-01

    Full Text Available Most marine mollusks are osmoconformers, in that, their body fluid osmolality changes in the direction of the change in environmental salinity. Marine mollusks exhibit a number of osmoregulatory mechanisms to cope with either hypo- or hyperosmotic stress. The effects of changes in salinity on the osmoregulatory mechanisms of the hard clam (Meretrix lusoria, an economically important species of marine bivalve for Taiwan have not been determined. In this study, we examined the effect of exposure to hypo (10‰- and hyper (35‰-osmotic salinity on hard clams raised at their natural salinity (20‰. The osmolality, [Na+], and [Cl-] of the hard clam hemolymph were changed in the same direction as the surrounding salinity. Further, the contents of total free amino acids including taurine in the gills and mantles were significantly upregulated in hard clam with increasing salinity. The gill Na+,K+-ATPase (NKA activity, the important enzyme regulating cellular inorganic ions, was not affected by the changed salinity. Mantle NKA activity, however, was stimulated in the 35‰ SW treatment. The taurine transporter (TAUT is related to the regulation of intracellular contents of taurine, the dominant osmolyte. Herein, a TAUT gene of hard clam was cloned and a TAUT antibody was derived for the immunoblotting. The TAUT mRNA expression of the mantle in hard clam was significantly stimulated in 35‰ SW, but protein expression was not modulated by the changed salinity. In gills of the hard clam with 10‰ SW, both TAUT mRNA and protein expressions were significantly stimulated, and it may reflect a feedback regulation from the decreased gills taurine content under long-term hypoosmotic acclimation. These findings suggest that TAUT expression is regulated differently in gills and mantles following exposure to alterations in environmental salinity. Taken together, this study used the physiological, biochemical and molecular approaches to simultaneously explore

  18. Ionic and Amino Acid Regulation in Hard Clam (Meretrix lusoria) in Response to Salinity Challenges.

    Science.gov (United States)

    Lin, Chia-Hao; Yeh, Po-Ling; Lee, Tsung-Han

    2016-01-01

    Most marine mollusks are osmoconformers, in that, their body fluid osmolality changes in the direction of the change in environmental salinity. Marine mollusks exhibit a number of osmoregulatory mechanisms to cope with either hypo- or hyperosmotic stress. The effects of changes in salinity on the osmoregulatory mechanisms of the hard clam (Meretrix lusoria, an economically important species of marine bivalve for Taiwan) have not been determined. In this study, we examined the effect of exposure to hypo (10‰)- and hyper (35‰)-osmotic salinity on hard clams raised at their natural salinity (20‰). The osmolality, [Na(+)], and [Cl(-)] of the hard clam hemolymph were changed in the same direction as the surrounding salinity. Further, the contents of total free amino acids including taurine in the gills and mantles were significantly upregulated in hard clam with increasing salinity. The gill Na(+), K(+)-ATPase (NKA) activity, the important enzyme regulating cellular inorganic ions, was not affected by the changed salinity. Mantle NKA activity, however, was stimulated in the 35‰ SW treatment. The taurine transporter (TAUT) is related to the regulation of intracellular contents of taurine, the dominant osmolyte. Herein, a TAUT gene of hard clam was cloned and a TAUT antibody was derived for the immunoblotting. The TAUT mRNA expression of the mantle in hard clam was significantly stimulated in 35‰ SW, but protein expression was not modulated by the changed salinity. In gills of the hard clam with 10‰ SW, both TAUT mRNA and protein expressions were significantly stimulated, and it may reflect a feedback regulation from the decreased gills taurine content under long-term hypoosmotic acclimation. These findings suggest that TAUT expression is regulated differently in gills and mantles following exposure to alterations in environmental salinity. Taken together, this study used the physiological, biochemical and molecular approaches to simultaneously explore the

  19. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic) Hard Clam,

    Science.gov (United States)

    1987-08-01

    nearby and lead to the aggregated that attaches to the substrate by distribution of clams. means of a byssus (Carriker 1961). When larvae settle, they...have better byssus gland (Belding 1912), the conditions for spat survival than un- active development of siphons and structured bottoms - probably...1961). The foot shortens and the greater numbers of juvenile hard clams byssus gland becomes nonfunctional. than control areas (Parker 1975). Ex

  20. Lipid characteristics of a seep clam, Mesolinga soliditesta: Comparison with those of two coastal clams, Meretrix lamarckii and Ruditapes philippinarum

    Science.gov (United States)

    Saito, Hiroaki; Murata, Masakazu; Hashimoto, Jun

    2014-12-01

    The lipids and fatty acids of two coastal clams, Meretrix lamarckii and Ruditapes philippinarum, collected at 5 and 1 m of depth, and a seep clam, Mesolinga soliditesta, collected at 331 m of depth, were examined to assess their lipid physiology and trophic relationship with their diets. The major fatty acids of lipids in Mer. lamarckii and R. philippinarum were 14:0, 16:0, 18:0, 16:1n-7, 18:1n-9, 18:1n-7, 20:4n-6, 20:5n-3, and 22:6n-3, while those of Mes. soliditesta were 16:0, 18:0, 16:1n-7, 18:1n-7, 20:1n-7, 20:1n-13, 20:2n-7, 15 (Δ5,13-20:2), and 22:2n-7,15 (Δ7,15-22:2). The major polyunsaturated fatty acids (PUFAs) in the Mer. lamarckii and R. philippinarum lipids consisted of various n-3 and n-6 long-chain (LC) PUFAs, such as 20:4n-6, 22:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3, while those in Mes. soliditesta muscle and viscera included various n-4 family PUFAs (18:3n-7, 18:4n-4, 20:2n-7, and 20:3n-7) with limited kinds of n-3 and n-6 PUFAs (20:4n-6 and 20:5n-3). These findings indicate that, like other common shallow-water clams, Mer. lamarckii and R. philippinarum ingest phytoplanktonic n-3 and n-6 LC-PUFAs, whereas Mes. soliditesta utilizes limited kinds of n-3 and n-6 LC-PUFAs. In contrast to the other two bivalves species, Mes. soliditesta yielded various n-4 and n-7 (n-4/n-7) PUFAs, which were assimilated from the chemosynthetic symbionts. The high diversity of PUFAs contained in the Mes. soliditesta lipids (n-3, n-4 family, and n-6 PUFAs) suggests that this species mixotrophically utilized both photosynthetic products and vent chemosynthetic nutrition derived from geothermal energy.

  1. Effects of water temperature change on immune function in surf clams, Mactra veneriformis (Bivalvia: Mactridae).

    Science.gov (United States)

    Yu, Jin Ha; Song, Jae Hee; Choi, Min Chul; Park, Sung Woo

    2009-09-01

    Surf clam, Mactra veneriformis is one of the crucial fishery resources in Korea. This study was performed to examine the immune functions of the surf clam under the stress of water temperature changes at 10 degrees C, 20 degrees C or 30 degrees C for 24h. Viable bacterial counts (VBC), total haemocyte count (THC), phagocytic activity, lysozyme activity, NRR times and SOD activity were assessed in three different water temperature groups. Clams held at 10 degrees C decreased in THC, lysozyme activity and NRR times, but phagocytic activity was increased. The highest temperature (30 degrees C) significantly increased in THC, whereas it decreased in phagocytic activity, lysozyme activity and NRR times. In clams maintained at 20 degrees C, phagocytic activity, lysozyme activity and NRR times were increased whereas THC was somewhat decreased with respect to clams held at 30 degrees C. However, water temperature changes did not elicit any alteration of VBC and SOD activity. The present study demonstrates that acute water temperature change affects the haemocytic and haemolymphatic functions, reducing immunosurveillance in stressed surf clam, M. veneriformis.

  2. Dimethylsulfoniopropionate in six species of giant clams and the evolution of dimethylsulfide after death

    Energy Technology Data Exchange (ETDEWEB)

    Hill, R.W.; Hill, S.D. [Michigan State Univ., East Lansing, MI (United States). Dept. of Zoology; Dacey, J.W.H. [Woods Hole Oceanographic Inst., Woods Hole, MA (United States). Dept. of Biology; Edward, A. [Micronesia College, Pohnpei (Micronesia, Federated States); Hicks, W.A. [Michigan State Univ., East Lansing, MI (United States). Dept. of Bioichemistry and Molecular Biology

    2004-05-01

    Dimethylsulfoniopropionate (DMSP) could accumulate in large concentrations in animals living symbiotically with algae. The giant clam family Tridacnidae accumulates DMSP because they have a symbiotic relationship with dinoflagellates (or zooxanthellae). In this study, well preserved clam tissues from the western Pacific Islands were analyzed to provide definitive evidence of DMSP in the tissues. Six of the common species in the Tridacnidae family were examined. The objective was to test the hypothesis that dimethyl sulfide (DMS) is released from clam tissues soon after death due to the breakdown of DMSP tissue. In particular, it determined if DMS is responsible for the problem of potent odours and off-taste that have hindered the commercial success of giant clams mariculture. Gas chromatography and mass spectrometry was used in this study to measure DMSP concentrations in siphonal mantle, byssal mantle, adductor muscle and gill tissues. The formation of DMS by tissues after death was documented. It was suggested that since giant clams associate with dinoflagellates, they could accumulate DMSP to high concentrations which could affect multiple properties and functions. It was concluded that the perishability of giant clam tissues is most likely due to the high concentrations of DMS produced one day post mortem. 15 refs., 2 tabs., 4 figs.

  3. Spatial distribution and bioaccumulation patterns in three clam populations from a low contaminated ecosystem

    Science.gov (United States)

    Velez, Cátia; Figueira, Etelvina; Soares, Amadeu; Freitas, Rosa

    2015-03-01

    When consuming bivalves, special concern should be taken to the total element burden. In order to assess this issue the present study aimed to measure the element levels in the sediments of different harvesting areas and relate them with clam accumulation; to assess the elements body burden, their availability for trophic transfer and relate it with total accumulation in clams, comparing the native (Ruditapes decussatus and Venerupis corrugata) and the invasive (Ruditapes philippinarum) species; to evaluate the human risk associated with the consumption of different clam species. The results showed that the element burden in clams does not reflect the sediment contamination and BAF values were higher in the less contaminated areas. Comparison of Maximum Levels (MLs) from international organizations with the concentration of elements in clams showed that As exceeded standard levels. The ingestion of less than 1 Kg per week of clams would result in exceeding the PTWI threshold for As. Furthermore, the results showed that, when comparing to other elements, As and Hg are more easily available to be transferred trophically.

  4. REVIEW: Symbiosis between the Giant Clams (Bivalvia: Cardiidae and Zooxanthellae (Dinophyceae

    Directory of Open Access Journals (Sweden)

    UDHI EKO HERNAWAN

    2008-01-01

    Full Text Available Giant clams are the largest bivalves in the world that maintain a mutual relationship with zooxanthellae. Individual giant clam can harbor heterogeneous zooxanthellae, at least four taxa in genus Symbiodinium. The Symbiodinium lives in the zooxanthellal tubular system, a tube structure arising from one of the diverticular duct of the clam’s stomach. Since the numbers of zooxanthellae is the one of some significant factors contributing to the clams growth and survival, the giant clams need to adjust the number of zooxanthellae for physiological reason with unclear mechanism. The important role of the symbiotic relationship to the clams can be seen on the survival, growth and nutrition of the clams. There are at least two significant factors determining the symbiosis, i.e. water temperature in related with level of light intensities and ammonium-phosphate rate. Some topic is still unclear, i.e. the determination of species in genus Symbiodinium, the mechanism for adjusting the population numbers of the algae and what kind of environmental factors determining the symbiosis. Thereby further research is still needed to clarify those missing.

  5. Growth and survival of endangered angelwing clam, Pholas orientalis fed different algal diets

    Directory of Open Access Journals (Sweden)

    M. Shirley M. Golez

    2011-12-01

    Full Text Available Mature angelwing clam, Pholas orientalis were collected from the wild and transported tothe laboratory for broodstock development. They were fed with mixed algal cultures of Isochrysisgalbana, Chaetoceros sp., and Tetraselmis sp. for a period of two months and a half to determine theeffects of these algal cultures on growth and survival of the broodstock. Growth in terms of length wasnot significantly different among the treatment groups, whereas, there was significant reduction in theweight of the clams in the group fed with a mixture of Isochrysis galbana, Chaetoceros sp., andTetraselmis sp. Survival of the clams decreased after two months of feeding with algal diets, withsignificant mortality observed in groups fed with a mixture of Isochrysis galbana and Tetraselmis sp. aswell as with the mixture of the three microalgae. All the water quality parameters in the rearing tankswere within the optimum levels required for optimum growth of the clams. These results showed thatmixed algal diets for broodstock development in angelwing clam have no direct effect on growth butmoderate effect on survival. Future studies are aimed towards determining other factors that willcontribute to better growth and survival of angelwing clam broodstock in captivity as well as for thesearch of alternative algal diets for angelwing broodstock, particularly by exploring the microalgae thatare found in their natural habitat.

  6. Evaluación de la tasa de aclaración de la almeja dulceacuícola Anodontites tortolis en un medio con coliformes Escherichia coli Clearance rate of faecal coliforms by netropical freshwater clam

    Directory of Open Access Journals (Sweden)

    Juan René Mallama Leyton

    2011-01-01

    Full Text Available En condiciones de laboratorio se evaluón acute; la eficiencia de la almeja de agua dulce (Anodontites tortolis) para disminuir la carga de coliformes fecales (Escherichia coli) determinada mediante filtración en membrana por 8 horas. El experimento se diseñó con dos tratamientos (densidades de seis (T1) y ocho almejas (T2) más un control) con tres replicaciones. Se encontraron diferencias significativas (PUnder laboratory conditions the efficiency of the freshwater clam Anodontites tortolis to diminish the quantity of faecal coliforms, determined by the membrane filtration method during eight hours was evaluated. The experiment was design with two treatments (two densities of six (T1) and eight clams (T2) and a control) and three replications. Statistical significant differences (P<0.05) according to the Kruskal-Wallis test for the clearance rates were found. The highest levels of remotion of E. coli belonged to the treatment in which there was the highest number of individuals. The clearance rate of the clams varied between 0.47 and 3.80 l.h-1.ind-1 which is reported in the literature. Removal levels showing A. tortolis suggest that this clam can be used as a biological resource for the treatment of the tertiary waters contaminated with faecal coliform bacteria.

  7. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  8. Phenology satellite experiment

    Science.gov (United States)

    Dethier, B. E. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The detection of a phenological event (the Brown Wave-vegetation sensescence) for specific forest and crop types using ERTS-1 imagery is described. Data handling techniques including computer analysis and photointerpretation procedures are explained. Computer analysis of multspectral scanner digital tapes in all bands was used to give the relative changes of spectral reflectance with time of forests and specified crops. These data were obtained for a number of the twenty-four sites located within four north-south corridors across the United States. Analysis of ground observation photography and ERTS-1 imagery for sites in the Appalachian Corridor and Mississippi Valley Corridor indicates that the recession of vegetation development can be detected very well. Tentative conclusions are that specific phenological events such as crop maturity or leaf fall can be mapped for specific sites and possible for different regions. Preliminary analysis based on a number of samples in mixed deciduous hardwood stands indicates that as senescence proceeds both the rate of change and differences in color among species can be detected. The results to data show the feasibility of the development and refinement of phenoclimatic models.

  9. Empirical Analysis of the Typical Breeding Pattern of Clam in Hongdao Town and the Preliminary Estimates of Costs and Benefits

    Institute of Scientific and Technical Information of China (English)

    Xijuan; YANG; Shijun; ZHANG

    2014-01-01

    Based on the survey data about clam breeding farmers in Hongdao Town in August 2011,this paper analyzes the production and operation of typical clam breeding pattern,and estimates the costs and benefits. Through the analysis of operation conditions and economic conditions of Hongdao clam breeding,this paper aims to explore a more reasonable and effective breeding pattern so as to reduce breeding costs and market risks,and increase breeding farmers’ income.

  10. The Communications Satellite as Educational Tool.

    Science.gov (United States)

    Long, Peter

    1982-01-01

    Drawing on the experiences of several countries, the author describes satellite technology, discusses the feasibility of satellite use in traditional educational institutions, and analyzes the role of satellites in social development. (SK)

  11. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). HARD CLAM.

    Science.gov (United States)

    1985-02-01

    days at 30’C (Loosanoff et al. comm.). 1951). To move, the clam byssus is cast Juvenile Seed Clam off and the foot is used for locomo- tion (Belding...1931). When the young When the veliger becomes 0.2 to clam reaches a desirable habitat, it 0.3 mm long, the shell thickens, a spins a new byssus and...currents (Anderson et The byssal gland of the seed clam al. 1979), but in the absence of secretes a tough thread, the byssus , predators, Carriker (1959

  12. ARDUSAT, an Arduino-Based CubeSat Providing Students with the Opportunity to Create their own Satellite Experiment and Collect Real-World Space Data

    Science.gov (United States)

    Geeroms, D.; Bertho, S.; De Roeve, M.; Lempens, R.; Ordies, M.; Prooth, J.

    2015-09-01

    Short for “Arduino Satellite”, ArduSat is an open-source Nanosatellite, based on the CubeSat standard. The extensive Arduino sensor suite on board gives students the opportunity to create their own satellite experiments and collect real-world space data using the Arduino open-source prototyping platform. From March until May 2014, two undergraduate physics students from Hasselt University used the downloadable ArduSat Software Development Kit which allowed them to design the command sequences they used to conduct their experiments.

  13. Using high-resolution satellite imagery to engage students in classroom experiences which meld research, the nature of science, and inquiry-based instruction

    Science.gov (United States)

    Pennycook, J.; LaRue, M.; Herried, B.; Morin, P. J.

    2013-12-01

    Recognizing the need to bridge the gap between scientific research and the classroom, we have developed an exciting activity which engages students in grades 5-12 using high-resolution satellite imagery to observe Weddell seal populations in Antarctica. Going beyond the scope of the textbook, students experience the challenge researchers face in counting and monitoring animal populations in the field. The activity is presented in a non-expert, non-technical exercise enriched for students, with background information, tutorials, and satellite imagery included. Teachers instruct their class in how to use satellite imagery analysis techniques to collect data on seal populations in the McMurdo Sound region of the Ross Sea, Antarctica. Students participate in this inquiry-based, open-ended exercise to evaluate changes in the seal population within and between seasons. The activity meets the New Generation Science Standards (NGSS) through inquiry-based, real-world application and supports seven Performance Expectations (PE) for grade 5-12. In addition, it offers students a glimpse into the work of a field biologist, promoting interest in entering the STEM career pipeline. As every new Antarctica season unfolds, new imagery will be uploaded to the website allowing each year of students to add their counts to a growing long-term dataset for the classroom. The activity files provide 1) a tutorial in how to use the images to count the populations, 2) background information about Weddell seals in the McMurdo Sound region of the Ross Sea for the students and the teachers, and 3) collections of satellite imagery for spatial and temporal analysis of population fluctuations. Teachers can find all activity files to conduct the activity, including student instructions, on the Polar Geospatial Center's website (http://z.umn.edu/seals). Satellite image, Big Razorback Island, Antarctica Weddell seals,Tent Island, Antarctica

  14. Change in metallothionein phosphorylation state in Mya arenaria clams: implication in metal metabolism and oxidative stress

    Directory of Open Access Journals (Sweden)

    F Gagné

    2010-01-01

    Full Text Available The contamination of the benthic environment poses a threat to long-lived sessile organisms such as clams. The purpose of this study was to investigate metal contamination in tissues and changes in metallothioneins (MT in respect to its redox status in Mya arenaria clams collected at three polluted sites. The phosphorylation state of MT was also investigated to determine whether this state is changed in clams collected at heavy-metal contaminated site and its involvement in cytoprotective signaling during stress contamination. The results show that clams collected at least one of the three polluted sites presented significantly higher concentrations of silver (Ag, arsenic (As, cobalt (Co, copper (Cu, mercury (Hg, nickel (Ni, tin (Sn and lead (Pb in tissues. In the visceral tissue, total MT levels and the reduced, metal-binding form of the protein were significantly induced at the sites. The phosphorylation of MT and mitochondrial activity, as determined by electron transport and cytochrome c oxidase activities, were also significantly reduced at the contaminated sites. Reduced phosphate levels in MT were negatively correlated with total MT levels, suggesting that decreased phosphorylation was involved in kinase-mediated signaling during cellular stress and could possibly alter the protein’s affinity to confer cytoprotection against heavy metal contamination. These preliminary investigations revealed that the phosphorylation state could change in polluted environment and provide some clues on the modulation of binding affinities during heavy-metal and oxidative stress in clams.

  15. Immune- and Pollution-mediated DNA Damage in Two Wild Mya arenaria Clam Populations

    Directory of Open Access Journals (Sweden)

    François Gagné

    2009-01-01

    Full Text Available In aquatic environments, genotoxicity results from the effects of pollution combined with the inflammatory response triggered by the immune system. Indeed, the production of nitrosylated DNA and proteins are though to arise from the production of peroxinitrite during phagocytosis and inflammation. The purpose of this study was to examine new DNA biomarkers that differentiate between immune- and pollution-mediated genotoxicity in wild clam populations. Intertidal clam populations were sampled and analyzed for gonadal DNA strand breaks, DNA nitrosylation and xanthine oxidoreductase (XOR activity (purine salvage pathway. The clam weight-to-shell-length ratio, the gonado-somatic index (GSI, age status, lipid peroxidation, xenobiotic conjugation activity (glutathione S-transferase (GST and phagocytic activity were examined to shed light on their relationships with the observed genotoxic endpoints. XOR activity and DNA strand breaks were generally elevated at polluted sites and correlated significantly with clam weight-to-shell-length ratios and DNA nitrosylation. DNA nitrosylation was also higher at some sites and correlated significantly with phagocytic activity and with DNA strand breaks. This study showed that DNA strand breaks were associated with both immune- and pollution-mediated effects. This suggests that there is a loss of DNA repair capacity due to the combined effects of aging, pollution and immune response in wild clam populations that are impacted by anthropogenic activity.

  16. Quantitative modeling for risk assessment of Vibrio parahaemolyticus in bloody clams in southern Thailand.

    Science.gov (United States)

    Yamamoto, Akio; Iwahori, Jun'ichiro; Vuddhakul, Varaporn; Charernjiratragul, Wilawan; Vose, David; Osaka, Ken; Shigematsu, Mika; Toyofuku, Hajime; Yamamoto, Shigeki; Nishibuchi, Mitsuaki; Kasuga, Fumiko

    2008-05-10

    A risk assessment of Vibrio parahaemolyticus in bloody clams (Anadara granosa) consumed in southern Thailand was conducted. This study estimated the prevalence and concentration of pathogenic V. parahaemolyticus in bloody clams at harvest and retail stages; and during this process, methods to detect the total and pathogenic V. parahaemolyticus were investigated. Consumption of bloody clams and cooking efficiency were studied using interviews and on-site observation of consumers. A beta-Poisson dose-response model was used to estimate probability of illness applying estimation methods for the most likely parameter values presented by USFDA. Microbial and behavioral data were analyzed by developing a stochastic model and the simulation gave a mean number of times a person would get ill with V. parahaemolyticus by consuming bloody clams at 5.6 x 10(-4)/person/year. Sensitivity analysis demonstrated the fraction of people who did not boil the clams properly was the primary factor in increasing risk. This study serves as an example of how a microbiological risk assessment with limited data collection and international cooperation leads to valuable local insight.

  17. Aquaculture Land-Use Policy: The Case of Clam Farming in Thaibinh Province, Vietnam

    Directory of Open Access Journals (Sweden)

    Thi Thu Hang NGO

    2016-12-01

    Full Text Available Policy-making and enforcement remains centralized in Vietnam. Policies have been formulated with less scientific and public justification, thus being largely bureaucratic and infeasible, and in many cases, they have created plagues for people at the grass-roots levels. This article focuses on the implementation of policies related to intertidal land-use and supports for clam farming in the Thaibinh province as a case study to explore the impacts of policies on clam farming and farmers. During the period of 2011–2013, provincial policies on intertidal land allocation and technical and financial supports had boosted clam farming development in the province to a surprising extent. Rapid expansion of the clam farming area has created significant consequences for the farming sector, as well as farmer’s lives. However, for the same provincial policies, but with different enforcement, different farming outcomes for clam farmers in the three study communes have resulted. Where farmers had more of a voice and choice in bidding for the intertidal areas they preferred, they faced fewer problems. It is, thus, suggested that a more decentralized policy-making and enforcement are needed, in which more scientific assessment and farmer participation are required to not only make government policy more successful in supporting farmers and achieving their expected outcomes, but also to provide farmers with more room to make their own farming decisions from which farming and marketing risks could be mitigated.

  18. Hydrocarbon concentrations in sediments and clams (Rangia cuneata) in Laguna de Pom, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Legorreta, T.; Gold-Bouchot, G.; Zapata-Perez, O. [Unidad Merida (Mexico)

    1994-01-01

    Laguna de Pom is a coastal lagoon within the Laguna de Terminos system in southern Gulf of Mexico. It belongs to the Grijalva-Usumacinta basin, and is located between 18{degrees} 33{prime} and 18{degrees} 38{prime} north latitude and 92{degrees} 01{prime} and 92{degrees} 14{prime} west longitude, in the Coastal Plain physiographic Province of the Gulf. It is ellipsoidal and approximately 10 km long, with a surface area of 5,200 ha and a mean depth of 1.5 m. Water salinity and temperature ranges are 0 to 13 {per_thousand} and 25{degrees} to 31{degrees}C, respectively. Benthic macrofauna is dominated by bivalves such as the clams Rangia cuneata, R. flexuosa, and Polymesoda carolineana. These clams provide the basis of an artisanal fishery, which is the main economic activity in the region. The presence of several oil-processing facilities around the lagoon is very conspicuous, which together with decreasing yields has created social conflicts, with the fishermen blaming the mexican state oil company (PEMEX) for the decrease in the clam population. This work aims to determine if the concentration of hydrocarbons in the clams (R. cuneata) and sediments of Laguna de Pom are responsible for the declining clam fishery. 11 refs., 4 figs., 2 tabs.

  19. Transcriptomic responses to low temperature stress in the Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Nie, Hongtao; Jiang, Liwen; Huo, Zhongming; Liu, Lianhui; Yang, Feng; Yan, Xiwu

    2016-08-01

    The Manila clam, Ruditapes philippinarum, is an economically important shellfish in marine aquaculture, with a broad thermal tolerance. The ability to cope with cold stress is quite important for the survival of aquatic species under natural conditions. A cold-tolerant clam that can survive the winter at temperatures below 0 °C might extend our understanding of the mechanisms underlying the response to cold stress. In this study, the transcriptional response of the Manila clam to cold stress (-1 °C) was characterized using RNA sequencing. The transcriptomes of a cold-treatment (O) group of clams, which survived under cold stress, and the control group (OC2), which was not subjected to cold stress, were sequenced with the Illumina HiSeq platform. In all, 148,593 unigenes were generated. Compared with the unigene expression profile of the control group, 1760 unigenes were up regulated and 2147 unigenes were down regulated in the O group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that signal transduction, mitochondrial metabolism, cellular component organization or biogenesis, and energy production processes were the most highly enriched pathways among the genes that were differentially expressed under cold stress. All these pathways could be assigned to the following biological functions in the cold-tolerant Manila clam: signal response to cold stress, antioxidant response, cell proliferation, and energy production.

  20. Blastopirellula cremea sp. nov., isolated from a dead ark clam.

    Science.gov (United States)

    Lee, Hae-Won; Roh, Seong Woon; Shin, Na-Ri; Lee, Jina; Whon, Tae Woong; Jung, Mi-Ja; Yun, Ji-Hyun; Kim, Min-Soo; Hyun, Dong-Wook; Kim, Daekyung; Bae, Jin-Woo

    2013-06-01

    Strain LHWP2(T), a novel, aerobic, budding, motile and ovoid bacterium belonging to the phylum Planctomycetes, was isolated from a dead ark clam (Scapharca broughtonii) from the south coast of Korea. Strain LHWP2(T) grew optimally at 30 °C, in the presence of 4% (w/v) NaCl, and at pH 7. The predominant cellular fatty acids were C16:0, C18:1ω7c and/or C18:1ω6c (summed feature 8) and C18:1ω9c. The major isoprenoid quinone was menaquinone-6 (MK-6). The dominant polar lipid was identified as phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Blastopirellula marina DSM 3645(T), with a 16S rRNA gene sequence similarity of 94.1%. The genomic DNA G+C content of strain LHWP2(T) was 49.5 mol%. Strain LHWP2(T) was distinguished from B. marina DSM 3645(T) based on its optimum salinity, acid production from substrates, assimilation of substrates and DNA G+C content. Overall, these phenotypic, genotypic and phylogenetic data suggest that strain LHWP2(T) should be classified as a novel species belonging to the genus Blastopirellula, for which the name Blastopirellula cremea sp. nov. is proposed. The type strain is LHWP2(T) (=KACC 15559(T)=JCM 17758(T)).

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

    Directory of Open Access Journals (Sweden)

    Girguis Peter R

    2008-12-01

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

  2. Toxicological evaluation of two pedigrees of clam Ruditapes philippinarum as bioindicators of heavy metal contaminants using metabolomics.

    Science.gov (United States)

    Ji, Chenglong; Cao, Lulu; Li, Fei

    2015-03-01

    Heavy metal pollution has been of great concern in the Bohai marine environment. Manila clam Ruditapes philippinarum has been used as a bioindicator in marine toxicology. In this study, NMR-based metabolomics was used to ascertain whether there were significant biological differences between two dominant pedigrees (White and Zebra) of clam and evaluate the suitability of two pedigrees for marine environmental toxicology, together with antioxidant enzymatic analysis. Our results indicated that there were significant biological differences between White and Zebra clams based on the metabolic profiles and antioxidant enzyme activities. In details, the metabolic profiles showed higher levels of amino acids and succinate in Zebra clam digestive glands and higher levels of ATP in White clam digestive glands, respectively. The superoxide dismutase activities in control White and Zebra clam samples were significantly different. Additionally, White clam was more sensitive to Cd based on the significant accumulation of Cd, antioxidant enzymatic alterations and sensitive metabolic changes. Overall, we concluded that White clam could be a preferable bioindicator for marine environmental toxicology. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Clam Ruditapes philippinarum recovery from short-term exposure to the combined effect of salinity shifts and Arsenic contamination.

    Science.gov (United States)

    Velez, Catia; Teixeira, Miguel; Wrona, Frederick J; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2016-04-01

    The current study assessed the biochemical alterations induced in the clam species Ruditapes philippinarum after exposure to salinity shifts (14, 28 and 42) and arsenic (As) contamination (0 and 2mg/L). The capacity of this species to recover (96h and 28 days) after exposure (96h) to both stressors, acting alone and in combination, was also evaluated. After exposure, regardless of the salinity tested, clams contaminated with As showed higher concentrations than non-contaminated specimens. After recovery, As concentration in clams decreased, with contaminated and non-contaminated specimens presenting similar values. The results obtained further demonstrated that exposure to As (2mg/L) at different salinities (salinities 14, 28 and 42) and salinity 42 (As 0mg/L) lead to an increase of lipid peroxidation and detoxification mechanisms in clams, compared with non-contaminated clams at salinities of 14 and 28. After recovery, at salinities 14 and 28, clams previously exposed to As were capable to decrease their oxidative stress to levels found in non-contaminated clams. Nevertheless, at salinity 42 both contaminated and non-contaminated clams did not survive. Overall results of measured energy-related parameters, indicators of oxidative stress, antioxidant and biotransformation enzymes indicated that As exposure and salinity shifts caused biochemical alterations in R. philippinarum, with stronger impacts when both stressors were acting in combination. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Organic contamination in clams, Venerupis aurea laeta and Cerastoderma edule glaucum, from Sicily (Italy).

    Science.gov (United States)

    Di Bella, Giuseppa; Potortì, Angela Giorgia; Licata, Patrizia; Pellizzeri, Vito; Ben Mansour, Hedi; Dugo, Giacomo; Lo Turco, Vincenzo

    2017-07-10

    Two species of edible clams Venerupis aurea laeta and Cerastoderma edule glaucum from Ganzirri Lake (Sicily, Italy) were investigated to determine OCP and PCB residues by GC-MS. Thirty-five samples were examined for two years in order to perform: a) their actual contamination; b) the daily dietary exposure of seafood consumers to the pollutants in question. In all the clams analysed in this study, PCB and OCP (4,4'-DDE) residues are always below the limits fixed by law. It seems that there is some seasonality of concentrations observed. In fact the more high concentrations of residues are detected in the hot months, for both species and years. Given the consumption of clams and the values obtained in this study for the two species analysed, it is possible estimate that the average daily dietary intake of NDL-PCB and of 4,4'-DDE for adults is really low.

  5. Gymnophallid digenean Parvatrema duboisi uses Manila clam as the first and second intermediate host.

    Science.gov (United States)

    Yanagida, Tetsuya; Shirakashi, Sho; Iwaki, Takashi; Ikushima, Noboru; Ogawa, Kazuo

    2009-09-01

    To identify the metacercariae of a gymnophallid trematode in the Manila clam Ruditapes philippinarum from the Ariake Sea, experimental infection and molecular analysis were conducted. Based on the morphology of adult worms obtained from experimentally infected mice, the parasite was identified as Parvatrema duboisi. Comparison of internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) sequences for metacercariae and sporocysts from Manila clams and adult worms collected from wild wigeon Anas penelope showed minor differences ranging from 0 to 0.8%. These data strongly suggest that in the Ariake Sea, the parasite has a lifecycle using the Manila clam as the first and second intermediate hosts and wigeon as the definitive host.

  6. High cycle fatigue properties of CLAM steel at 723 K and 823 K

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun; Zhai, Xiangwei; Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn; Li, Chunjing; Huang, Qunying

    2015-11-15

    Highlights: • High cycle fatigue properties of CLAM steel were investigated at 723 K and 823 K. • The condition fatigue limit at N = 10{sup 7} were 275 MPa and 235 MPa at 723 K and 823 K. • Fatigue strength decreased when stress and temperature increased at 723 K and 823 K. • Dislocation density decrease and subgrain coarsening during the test process were the possible reasons for fatigue limit decrease. - Abstract: This paper highlights the results of a study on the high cycle fatigue strength and fracture mechanism of China Low Activation Martensitic (CLAM) steel. The high cycle fatigue test results showed that the fatigue strength of CLAM steel decreased with the temperature, and the condition fatigue strengths (N = 10{sup 7}) were 275 MPa and 235 MPa at 723 K and 823 K, respectively. The fractograph results indicated that the fractures were mainly initiated from the surface of the specimen.

  7. Responses of Manila clam growth and its food sources to global warming in a subarctic lagoon in Japan

    Science.gov (United States)

    Yoon, Seokjin; Abe, Hiroya; Kishi, Michio J.

    2013-12-01

    Akkeshi Lake is a subarctic shallow brackish lagoon located in Hokkaido, Japan. The Manila clam, Ruditapes philippinarum, is cultured in sandy sediments at the shallow, intertidal flat near the mouth of the lake. To quantitatively evaluate the effects of environmental factors such as water temperature and food availability on the growth of the Manila clam and to estimate the responses of Manila clam growth and food availability to global warming in Akkeshi Lake, we developed a numerical model by coupling a three-dimensional ecosystem model with a bioenergetics model for the growth of the Manila clam. We ran the model under two different conditions: the present condition and the global warming condition. For the global warming condition, water temperature was increased by 2 °C at the open boundary for the entire computational period. The growth of the Manila clam was limited by water temperature and food availability. The Manila clam grew up to 1.33 g dry weight ind.-1 at the lake mouth (station A) for 5 years, whereas it grew up to 1.00 g dry weight ind.-1 at the lake center (station B). The difference in the biomass of the Manila clam between two stations was due to the difference in food availability. Under the global warming condition, the water temperature limitation for the Manila clam was relaxed with a water temperature increase. The Manila clam grew up to 1.55 g dry weight ind.-1 at station A and 1.10 g dry weight ind.-1 at station B. While the growth of the Manila clam was improved in the lake under the global warming condition, its food sources, especially phytoplankton, decreased because of ingestion increases of grazers.

  8. Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Tengxiu [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing, E-mail: lishunxing@mnnu.edu.cn [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China); Chen, Lihui [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Zheng, Fengying; Huang, Xu-Guang [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China)

    2014-10-15

    Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams.

  9. Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation

    Science.gov (United States)

    Chang, Yongqin; Zhang, Jing; Li, Xiaolin; Guo, Qiang; Wan, Farong; Long, Yi

    2014-12-01

    This work presents an early look at irradiation effects on China low activation martensitic (CLAM) steel with nanocrystalline grains (NC-CLAM steels) under 500 keV Xe-ion bombardment at room temperature to doses up to 5.3 displacements per atom (dpa). The microstructure in the topmost region of the steel is composed of nanocrystalline grains with an average diameter of 13 nm. As the samples were implanted at low dose, the nanocrystalline grains had martensite lath structure, and many dislocations and high density bubbles were introduced into the NC-CLAM steels. As the irradiation dose up to 5.3 dpa, a tangled dislocation network exists in the lath region, and the size of the bubbles increases. X-ray diffraction results show that the crystal quality decreases after irradiation, although the nanocrystals obviously coarsen. Grain growth under irradiation may be ascribed to the direct impact of the thermal spike on grain boundaries in the NC-CLAM steels. In irradiated samples, a compressive stress exists in the surface layer because of grain growth and irradiation-introduced defects, while the irradiation introduced grain-size coarsening and defects gradients from the surface to matrix result in a tensile stress in the irradiated NC-CLAM steels. Nanoindentation was used to estimate changes in mechanical properties during irradiation, and the results show that the hardness of the NC-CLAM steels increases with increasing irradiation dose, which was ascribed to the competition between the grain boundaries and the irradiation-introduced defects.

  10. Quantifying the Impact of BOReal Forest Fires on Tropospheric Oxidants Over the Atlantic Using Aircraft and Satellites (BORTAS) Experiment: Design, Execution, and Science Overview

    Science.gov (United States)

    Palmer, Paul I.; Parrington, Mark; Lee, James D.; Lewis, Alistair C.; Richard, Andrew R.; Bernath, Peter F.; Pawson, Steven; daSilva, Arlindo M.; Duck, Thomas J.; Waugh, David L.; Tarasick, Daivd W.; Andrews, Stephen; Aruffo, Eleonora; Bailey, Loren J.; Barrett, Lucy; Bauguitte, Stephan J.-B.; Curry, Kevin R.; DiCarlo, Piero; Chisholm, Lucy; Dan, Lin; Forster, Grant; Franklin, Jonathan E.; Gibson, Mark D.; Griffin, Debora; Moore, David P.

    2013-01-01

    We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of airmasses that contain the emission products from seasonal boreal wildfires and how these airmasses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada. The planned July 2010 deployment of the ARA was postponed by 12 months because of activities related to the dispersal of material emitted by the Eyjafjallaj¨okull volcano. However, most other planned model and measurement activities, including ground-based measurements at the Dalhousie University Ground Station (DGS), enhanced ozonesonde launches, and measurements at the Pico Atmospheric Observatory in the Azores, went ahead and constituted phase A of the experiment. Phase B of BORTAS in July 2011 included the same measurements, but included the ARA, special satellite observations and a more comprehensive measurement suite at the DGS. Integrating these data helped us to describe pyrogenic plumes from wildfires on a wide spectrum of temporal and spatial scales. We interpret these data using a range of chemistry models, from a near-explicit gas-phase chemical mechanism to regional and global models of atmospheric transport and lumped chemistry. We also present an overview of some of the new science that has originated from this project.

  11. Time-transfer experiments between satellite laser ranging ground stations via one-way laser ranging to the Lunar Reconnaissance Orbiter

    Science.gov (United States)

    Mao, D.; Sun, X.; Skillman, D. R.; Mcgarry, J.; Hoffman, E.; Neumann, G. A.; Torrence, M. H.; Smith, D. E.; Zuber, M. T.

    2014-12-01

    Satellite laser ranging (SLR) has long been used to measure the distance from a ground station to an Earth-orbiting satellite in order to determine the spacecraft position in orbit, and to conduct other geodetic measurements such as plate motions. This technique can also be used to transfer time between the station and satellite, and between remote SLR sites, as recently demonstrated by the Time Transfer by Laser Link (T2L2) project by the Centre National d'Etudes Spatiaes (CNES) and Observatorire de la Cote d'Azur (OCA) as well as the Laser Time Transfer (LTT) project by the Shanghai Astronomical Observatory, where two-way and one-way measurements were obtained at the same time. Here we report a new technique to transfer time between distant SLR stations via simultaneous one-way laser ranging (LR) to the Lunar Reconnaissance Orbiter (LRO) spacecraft at lunar distance. The major objectives are to establish accurate ground station times and to improve LRO orbit determination via these measurements. The results of these simultaneous LR measurements are used to compare the SLR station times or transfer time from one to the other using times-of-flight estimated from conventional radio frequency tracking of LRO. The accuracy of the time transfer depends only on the difference of the times-of-flight from each ground station to the spacecraft, and is expected to be at sub-nano second level. The technique has been validated by both a ground-based experiment and an experiment that utilized LRO. Here we present the results to show that sub-nanosecond precision and accuracy are achievable. Both experiments were carried out between the primary LRO-LR station, The Next Generation Satellite Laser Ranging (NGSLR) station, and its nearby station, Mobile Laser System (MOBLAS-7), both at Greenbelt, Maryland. The laser transmit time from both stations were recorded by the same event timer referenced to a Hydrogen maser. The results have been compared to data from a common All

  12. China Launches First Ever Nano-satellite

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    China successfully launched two scientific satellites, including a nano-satellite for the first time, heralding a breakthrough in space technology. A LM-2C rocket carrying Nano-Satellite I (NS-1), which weighs just 25kg and an Experiment Satellite I, weighing 204kg blasted off at 11:59 p.m. on April 18,

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    Biochemical compositions were determined for eggs, D-shaped larvae, umbo larvae and pediveliger of the short neck clam Paphia malabarica Chemnitz. Spawned eggs were composed of 63.2% protein, 25.4% lipid and 11.4% carbohydrate. After 48 h...

  14. Effect of Epinephrine on the Settlement and Metamorphosis of Manila Clam Larvae

    Institute of Scientific and Technical Information of China (English)

    LU Sumin; BAO Zhenmin; LIU Hui; FANG Jianguang

    2006-01-01

    Chemical inducement and DDRT-PCR (differential display reverse transcription PCR) are adopted to investigate the effect of epinephrine (EPI) on the settlement and metamorphosis of Manila clam larvae. Chemical inducement shows that EPI has an effect to some extent on the metamorphosis of Manila clam larvae at all concentrations and in all treatments designed. The most significant result of inducement is obtained at the concentration of 10-6 molL-1 and for 4 h. DDRT-PCR using six primer pairs shows that the gene expression pattern is quite different between EPI treatment and the control. Three hundred and forty-three amplification bands are obtained in total, among which, 67 (19.53%) are differentially appeared.Therefore, EPI has an effect on the gene expression of the eye spot larval Manila clam. It can be hypothesized that EPI is a settlement and metamorphosis inducer for Manila clam. EPI may lead to larvae settlement and metamorphosis by binding to the receptors on the membrane and then changing the gene expression of larvae cells.

  15. First molluscan antimicrobial peptide hydramacin in Manila clam: molecular characterization and expression analysis

    Directory of Open Access Journals (Sweden)

    Youngdeuk Lee

    2014-06-01

    Full Text Available Objective: To investigate molecular characterization and the immune responses of Manila clam hydramacin (Rp-hdmc. Methods: cDNA sequence of hydramacin was isolated from Manila clam transcriptome database. Molecular characterization of hydramacin cDNA was performed by BLAST and SWISS-MODEL bioinformatics programs. Tissue-specific expression and transcriptional regulation after Vibrio tapetis challenge was done by quantitative real time PCR. Results: Rp-hdmc has 291 bp open reading frame (ORF, encoding 97 amino acids with a mature hydramacin consisting of 77 amino acid residues. In un-challenged clam, Rp-hdmc was constitutively expressed in all tested tissues and the highest expression level was detected in gill. After pathogenic bacteria Vibrio tapetis challenge, Rp-hdmc mRNA was up-regulated in gill and hemocytes. Conclusions: We identified hydramacin cDNA (Rp-hdmc from mollusk Manila clam that shows the characteristic features of hydramacin sequence. It has eight cysteine residues with four disulfide linkages, three helices and two β-strands in secondary structure. Expression results after V. tapetis challenges suggest that Rp-hdmc is involved in immune response against pathogenic bacteria.

  16. A SOCIAL COST-BENEFIT ANALYSIS OF A SMALL-SCALE CLAM ...

    African Journals Online (AJOL)

    A SOCIAL COST-BENEFIT ANALYSIS OF A SMALL-SCALE CLAM FISHERY IN ... as well as damage the aesthetic and ecological attributes of the beach system, ... the highest NPV was obtained for the scenario in which total production was ...

  17. Allometric relationships in the bioconcentration of heavy metals by the edible tropical clam Gafrarium tumidum

    Energy Technology Data Exchange (ETDEWEB)

    Hedouin, L. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Laboratoire de Biologie et d' Environnement Marins, FRE 2727, La Rochelle University, 22 Av. Michel Crepeau, F-17000 La Rochelle (France); Institut de Recherche pour le Developpement, Centre d' Oceanologie de Marseille, Station Marine d' Endoume, Rue de la Batterie des Lions, F-13007 Marseille (France); Metian, M. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Teyssie, J.-L. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Fowler, S.W. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco); Fichez, R. [Institut de Recherche pour le Developpement, Centre d' Oceanologie de Marseille, Station Marine d' Endoume, Rue de la Batterie des Lions, F-13007 Marseille (France); Warnau, M. [International Atomic Energy Agency-Marine Environment Laboratory, 4 Quai Antoine 1er, MC-98000 Monaco (Monaco)]. E-mail: m.warnau@iaea.org

    2006-07-31

    Although metal contamination is a problem of major concern in the lagoon of New Caledonia due to intense mining activities conducted on land, very little is known on the metal ecotoxicology of local marine organisms. The clam Gafrarium tumidum was investigated to assess its usefulness as a bioindicator species of metal contamination in this lagoon. More particularly, allometric relationships between metal accumulation and clam size were determined for five common metals in New Caledonian lagoon waters (Cd, Cr, Co, Zn and Ag) using a highly sensitive radiotracer technique. Experimental results showed that allometric relationships were dependent on the element and on the body compartment considered. As a rule, allometric relationships of metal concentration factor were more pronounced in shell than in soft parts. Significant relationships with clam size for Cd, Cr, Co and Zn followed inverse power functions. In contrast, the degree of Ag bioaccumulation was positively correlated with size. In view of the literature on Ag in bivalves, the latter observation suggests the occurrence of a specific detoxification mechanism (sequestration) that would be more efficient in old individuals. Overall, the experimental results indicate that the use of G. tumidum as a bioindicator in monitoring programmes requires selecting individuals of a specific size range in order to obtain comparable information about ambient metal levels. Since the size effect is greatest among smaller individuals, it is recommended to select clams with a shell width greater than 35 mm.

  18. Multidrug-resistant and epidemic clones of Escherichia coli from natural beds of Venus clam.

    Science.gov (United States)

    Vignaroli, C; Di Sante, L; Leoni, F; Chierichetti, S; Ottaviani, D; Citterio, B; Biavasco, F

    2016-10-01

    Epidemic Escherichia coli clones have been recovered in marine sediment along the coast of Marche, an Adriatic region in central Italy. In the present study, E. coli strains from the clam Chamelea gallina, sampled from seven natural beds in the same area, were detected. Selected E. coli isolates from all sampling sites were screened for antimicrobial susceptibility, genetic diversity and correlation. The majority (60%) belonged to phylogroups A or B1, 31% to the other groups (B2, C, D, E, F), 8% to cryptic clades, and 1% were untypable. Moreover, 33.3% of isolates were resistant to at least one drug and 11% were multidrug resistant (MDR). The most common resistance was to tetracycline, ampicillin, and streptomycin. No clonality was detected, but the strains' high genetic heterogeneity pointed at multiple sources of microbiological contamination. MLST analysis found potentially pathogenic and even epidemic MDR strains in clams collected in class A (ST746 and ST46) and class B (ST393, ST58 and ST131) areas, indicating that strains of clinical origin are detectable in clams. These data highlight that eating raw or lightly cooked clams may pose a health risk if purification is not performed or is ineffective.

  19. Native and introduced clams biochemical responses to salinity and pH changes.

    Science.gov (United States)

    Velez, Catia; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-10-01

    By the end of year 2100 physiological and biochemical performance of aquatic organisms are expected to become strongly affected by salinity and pH shifts, which in turn may favor the conditions for introduced species to invade new ecosystem areas. Given this, we evaluated the effects of salinity and pH changes in native Ruditapes decussatus and introduced Ruditapes philippinarum clams, by measuring different biomarkers related to oxidative stress, metabolic activity and osmoregulation capacity. Results showed that extreme salinities induced mortality in both species, while all clams survived under low pH (7.3). Both species mobilized glycogen as a source of energy towards cells protection mechanisms under extreme salinities. The native species presented higher lipid peroxidation levels while the introduced species was able to prevent oxidative damages through the induction of antioxidant enzymes at most extreme salinities. R. philippinarum also induced CA activity to balance the ion homeostasis at extreme salinities. In contrast, low pH induced oxidative damages, an increase of antioxidant (catalase), detoxification (glutathione S-transferases) and osmoregulation (carbonic anhydrase) mechanisms in R. philippinarum compared to the native clams. Overall, salinity and pH changes can alter physiological and biochemical status of native and introduced clam species. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Cadmium sulfide quantum dots induce oxidative stress and behavioral impairments in the marine clam Scrobicularia plana.

    Science.gov (United States)

    Buffet, Pierre-Emmanuel; Zalouk-Vergnoux, Aurore; Poirier, Laurence; Lopes, Christelle; Risso-de-Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Perrein-Ettajani, Hanane; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2015-07-01

    Cadmium sulfide (CdS) quantum dots have a number of current applications in electronics and solar cells and significant future potential in medicine. The aim of the present study was to examine the toxic effects of CdS quantum dots on the marine clam Scrobicularia plana exposed for 14 d to these nanomaterials (10 µg Cd L(-1) ) in natural seawater and to compare them with soluble Cd. Measurement of labile Cd released from CdS quantum dots showed that 52% of CdS quantum dots remained in the nanoparticulate form. Clams accumulated the same levels of Cd regardless of the form in which it was delivered (soluble Cd vs CdS quantum dots). However, significant changes in biochemical responses were observed in clams exposed to CdS quantum dots compared with soluble Cd. Increased activities of catalase and glutathione-S-transferase were significantly higher in clams exposed in seawater to Cd as the nanoparticulate versus the soluble form, suggesting a specific nano effect. The behavior of S. plana in sediment showed impairments of foot movements only in the case of exposure to CdS quantum dots. The results show that oxidative stress and behavior biomarkers are sensitive predictors of CdS quantum dots toxicity in S. plana. Such responses, appearing well before changes might occur at the population level, demonstrate the usefulness of this model species and type of biomarker in the assessment of nanoparticle contamination in estuarine ecosystems.

  1. Genetic diversity of European populations of the invasive soft-shell clam Mya arenaria (Bivalvia)

    NARCIS (Netherlands)

    Lasota, R.; Hummel, H.; Wolowicz, M.

    2004-01-01

    The genetic diversity of the soft-shell clam Mya arenaria from seven locations in Europe (two stations in the southern Baltic Sea (the Gulf of Gdansk) and two in the North Sea (Veerse Meer and Oosterschelde), and three additional stations in the Denmark Straits and Bay of Biscay) was determined usin

  2. CLAM - CoLlAborative eMbedded networks for submarine surveillance: An overview

    NARCIS (Netherlands)

    Meratnia, Nirvana; Havinga, Paul J.M.; Casari, Paolo; Petrioli, Chiara; Grythe, Knut; Husoy, Thor; Zorzi, Michele

    2011-01-01

    This paper provides an overview of the CLAM project, which aims at developing a collaborative embedded monitoring and control platform for submarine surveillance by combining cutting edge acoustic vector sensor technology and 1D, 2D, 3D sensor arrays, underwater wireless sensor networks protocol des

  3. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval

    Directory of Open Access Journals (Sweden)

    J. A. Sauvaud

    Full Text Available The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ~0–14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ~10 eV–20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ~3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ~9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ~16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be

  4. Uptake of dissolved Ag, Cd, and Co by the clam, Macoma balthica: relative importance of overlying water, oxic pore water, and burrow water.

    Science.gov (United States)

    Griscom, Sarah B; Fisher, Nicholas S

    2002-06-01

    The facultative deposit-feeding clam Macoma balthica is used as a bioindicator organism for assessing coastal metal contamination. Previous work has evaluated the assimilation of metals from different possible food sources for this clam, but no studies have measured the uptake rates of metals from different dissolved sources. This study specifically compares three different dissolved sources: overlying water (SW), oxic pore water (OPW) from a depth of deposit feeding), and burrow water (BW) (a mixture of anoxic pore water and overlying water). Uptake rates of dissolved Ag, Cd, and Co in M. balthica were measured in short-term laboratory experiments using radiotracers. Clams were exposed to metals in water only for SW and surface OPW treatments. In the BW treatment, metal uptake was compared in clams placed in radiolabeled organic-poor or organic-rich sediment under conditions in which feeding was inhibited. Uptake rate constantsfrom SW for Ag, Cd, and Co were 0.35, 0.033, and 0.035 L g(-1) day(-1), respectively. Lower uptake of dissolved metals from OPW was noted but was only significant for Co. Metal uptake from BW and SW were also comparable; however, the trend showed lower Ag and higher Co uptake from BW. Metal distributions and concentrations in the two radiolabeled sediments were affected by active irrigation of SW into the burrows; dissolved metal concentrations in BW were approximately 30% lower than that in the bulk pore water concentrations. In the organic-rich sediment, Cd and Ag partitioned more in the dissolved phase (sensitivity analysis using measured rate constants for uptake and a range of metal concentrations from field studies suggested that, under most conditions, uptake of dissolved Ag is primarily from OPW, Co is mostly from BW, and Cd uptake varies depending on its concentration in each compartment. Little Co or Ag is likely to be taken up from SW, whereas 20-50% of Cd may be accumulated from this source. Thus, SW, OPW, and BW are all

  5. Experiences in Applying Earth Observing Satellite Technology in SERVIR Regions with an Emphasis on Disasters: Successes, Lessons and Paths Forward

    Science.gov (United States)

    Anderson, Eric

    2017-01-01

    Earth observing satellites offer a unique perspective of our environment from the vantage point of space. Repeated measurements of the Earths subsystems such as the biosphere, atmosphere, lithosphere, hydrosphere, and of humans interactions with their environments, allow for a better understanding of Earth system processes, and they can provide input for decision making in areas of environmental management and disaster risk reduction. SERVIR is a joint initiative of the US National Aeronautics and Space Administration (NASA) and the US Agency for International Development (USAID) that began in 2005 and has been active in applying Earth observations for sustainable development in many regions around the world, recently the Lower Mekong and West Africa regions. This talk will highlight some successes achieved and lessons learned through SERVIR in Central America, Eastern Southern Africa, and the Hindu Kush-Himalaya region, focusing on disasters. We will also present opportunities for enhanced decision making with Earth observations and geospatial technologies in the Lower Mekong region.

  6. An implementation of Software Defined Radios for federated aerospace networks: Informing satellite implementations using an inter-balloon communications experiment

    Science.gov (United States)

    Akhtyamov, Rustam; Cruz, Ignasi Lluch i.; Matevosyan, Hripsime; Knoll, Dominik; Pica, Udrivolf; Lisi, Marco; Golkar, Alessandro

    2016-06-01

    Novel space mission concepts such as Federated Satellite Systems promise to enhance sustainability, robustness, and reliability of current missions by means of in-orbit sharing of space assets. This new paradigm requires the utilization of several technologies in order to confer flexibility and re-configurability to communications systems among heterogeneous spacecrafts. This paper illustrates the results of the experimental demonstration of the value proposition of federated satellites through two stratospheric balloons interoperating with a tracking ground station through Commercial Off-The-Shelf Software Defined Radios (SDRs). The paper reports telemetry analysis and characterizes the communications network that was realized in-flight. Furthermore, it provides details on an in-flight anomaly experienced by one of the balloons, which was recovered through the use of the federated technology that has been developed. The anomaly experienced led to the early loss of the directional link from the ground station to the affected stratospheric balloon node after 15 min in flight. Nevertheless, thanks to the federated approach among the systems, the ground station was still able to retrieve the balloon's data in real time through the network system, for which the other balloon operated as a federated relay for 45 min in flight, uninterrupted. In other words, the federated approach to the system allowed triplicating the useful lifetime of the defective system, which would have not been possible to realize otherwise. Such anomaly coincidentally demonstrated the value of the federated approach to space systems design. The paper paves the way for future tests on space assets.

  7. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  8. [Experiment with rats on a 22-day flight on the "Kosmos-605" biological satellite (objectives and methods)].

    Science.gov (United States)

    Il'in, E A; Serova, L V; Noskin, A D

    1976-01-01

    In 1974 a rat experiment was carried out onboard the Cosmos-605 biosatellite. Inflight Wistar rats were kept unrestrained in small cages. The cages were equipped with a feeder, water supply, light source and a ventilation device. The state of the animals was assessed with respect to their motor activity. The flight experiment was preceded by a number of preparatory runs and testinns that were completed with an end-to-end experiment in a biosatellite mockup. The flight experiment was paralleled by the ground-based synchroneous experiment which simulated almost entirely the flight profile. For each experiment rats were selected and trained during a month's observation. Postflight rats were exposed to clinical, physiological, morphological, cytochemical and biochemical investigations. Tissue examinations were performed on the 2nd-3rd day (20 rats) and 26-27th day (12 rats) after flight. Four rats were kept to study remote aftereffects.

  9. Gene transcription and biomarker responses in the clam Ruditapes philippinarum after exposure to ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Milan, Massimo; Pauletto, Marianna; Patarnello, Tomaso; Bargelloni, Luca [Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell' Universita 16, Legnaro (Padova) (Italy); Marin, Maria Gabriella [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy); Matozzo, Valerio, E-mail: matozzo@bio.unipd.it [Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova (Italy)

    2013-01-15

    Pharmaceuticals are a class of emerging environmental contaminants that continuously enter aquatic environments. Presently, little information is available about the effects of these substances on non-target organisms, such as bivalves. We investigated the effects of ibuprofen (IBU) on the clam Ruditapes philippinarum. Clams were exposed for 1, 3, 5 and 7 days to 0, 100 and 1000 {mu}g IBU/L, and established biomarker responses (haemolymph lysozyme, gill acetylcholinesterase and digestive gland superoxide dismutase activities) as well as digestive gland transcriptome were evaluated. A two-way ANOVA revealed significant effects of both 'IBU concentration' and 'exposure duration' on biomarker responses. Overall, the enzyme activities were generally lower in IBU-exposed clams than in controls. Although limited knowledge of the mollusc transcriptome makes it difficult to interpret the effects of IBU on clams, the gene transcription analysis using DNA microarrays enabled the identification of the putative molecular mode of action of the IBU. The functional analysis of differentially transcribed genes suggests that IBU can interfere with various signalling pathways in clams, such as arachidonic acid metabolism, apoptosis, peroxisomal proliferator-activated receptors, and nuclear factor-kappa B. In addition, several genes involved in the metabolism of xenobiotics (e.g., glutathione S-transferase, sulfotransferase, cytochrome P450) were also found to be significantly affected by IBU exposure. In summary, the integrated approach of gene transcription analysis and biomarker responses facilitated the elucidation of the putative mechanisms of action of IBU in non-target species.

  10. Accumulation of petroleum hydrocarbons and heavy metals in clams (Ruditapes philippinarum) in Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    MA Haiqing; SONG Qian; WANG Xuchen

    2009-01-01

    Accumulation and distributions of aliphatic and polyaromatic hydrocarbons (PAHs) and heavy metals were measured in tissues of the clam Ruditapes philippinarum collected from 5 sites in Jiaozhou Bay, Qingdao, China. The concentrations of total aliphatic hydrocarbon and PAHs ranged from 570 to 2 574 ng/gdw (gram dry weight) and from 276 to 939 ng/gdw, in the most and least polluted sites, respectively. The bio-accumulation of hydrocarbons and PAHs in the clams appeared to be selective. Aliphatic hydrocarbons were predominantly represented by short chain (clams was probably related to the physiological and bio-kinetic processes that were energetically favorable for uptake of compounds with fewer rings. Accumulation of the metals Cd, Cu, Zn, Pb, Cr, Hg, and As in the clam tissues also showed high variability, ranging from 0.043 to 87μg/gdw. Among the 7 detected metals, Zn, Cd, Cu, and As had a particularly high potential of accumulation in R. philippinarum. In general, a positive correlation was found between the tissue concentrations and sediment concentrations of hydrocarbons and of some metals. Our study suggests that moderate contamination with polyaromatic hydrocarbons, and low to moderate contamination with metals, currently exists for clam R. philippinarum in Jiaozhou Bay, in comparison with other regional studies. A long-term monitoring program is certainly needed for assessment of the potential ecological influence and toxicity of these contaminants of R. philippinarum in Jiaozhou Bay.

  11. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-02-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  12. New polymorphic microsatellite markers derived from hemocyte cDNA library of Manila clam Ruditapes philippinarum challenged by the protozoan parasite Perkinsus olseni

    Science.gov (United States)

    Kang, Hyun-Sil; Hong, Hyun-Ki; Park, Kyung-Il; Cho, Moonjae; Youn, Seok-Hyun; Choi, Kwang-Sik

    2017-03-01

    Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.

  13. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  14. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  15. A new laser-ranged satellite for General Relativity and space geodesy: I. An introduction to the LARES2 space experiment

    Science.gov (United States)

    Ciufolini, Ignazio; Paolozzi, Antonio; Pavlis, Erricos C.; Sindoni, Giampiero; Koenig, Rolf; Ries, John C.; Matzner, Richard; Gurzadyan, Vahe; Penrose, Roger; Rubincam, David; Paris, Claudio

    2017-08-01

    We introduce the LARES 2 space experiment recently approved by the Italian Space Agency (ASI). The LARES 2 satellite is planned for launch in 2019 with the new VEGA C launch vehicle of ASI, ESA and ELV. The orbital analysis of LARES 2 experiment will be carried out by our international science team of experts in General Relativity, theoretical physics, space geodesy and aerospace engineering. The main objectives of the LARES 2 experiment are gravitational and fundamental physics, including accurate measurements of General Relativity, in particular a test of frame-dragging aimed at achieving an accuracy of a few parts in a thousand, i.e., aimed at improving by about an order of magnitude the present state-of-the-art and forthcoming tests of this general relativistic phenomenon. LARES 2 will also achieve determinations in space geodesy. LARES 2 is an improved version of the LAGEOS 3 experiment, proposed in 1984 to measure frame-dragging and analyzed in 1989 by a joint ASI and NASA study.

  16. Bio-accumulation of some trace metals in the short-neck clam Paphia malabarica from Mandovi estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    KrishnaKumari, L.; Kaisary, S.; Rodrigues, V.

    concentration and accumulation, are bioavail- ability of metals, season, size, sex, hydrodynamics of the environment, changes in tissue composition and reproductive cycle (Boyden and Phillips, 1981). The short-neck clam of fish. Wilfred and Abdul (1994) reported...

  17. EPSAT-SG: a satellite method for precipitation estimation; its concepts and implementation for the AMMA experiment

    Directory of Open Access Journals (Sweden)

    J. C. Bergès

    2010-01-01

    Full Text Available This paper presents a new rainfall estimation method, EPSAT-SG which is a frame for method design. The first implementation has been carried out to meet the requirement of the AMMA database on a West African domain. The rainfall estimation relies on two intermediate products: a rainfall probability and a rainfall potential intensity. The first one is computed from MSG/SEVIRI by a feed forward neural network. First evaluation results show better properties than direct precipitation intensity assessment by geostationary satellite infra-red sensors. The second product can be interpreted as a conditional rainfall intensity and, in the described implementation, it is extracted from GPCP-1dd. Various implementation options are discussed and comparison of this embedded product with 3B42 estimates demonstrates the importance of properly managing the temporal discontinuity. The resulting accumulated rainfall field can be presented as a GPCP downscaling. A validation based on ground data supplied by AGRHYMET (Niamey indicates that the estimation error has been reduced in this process. The described method could be easily adapted to other geographical area and operational environment.

  18. Minority University System Engineering: A Small Satellite Design Experience Held at the Jet Propulsion Laboratory During the Summer of 1996

    Science.gov (United States)

    Ordaz, Miguel Angel

    1997-01-01

    The University of Texas at El Paso (UTEP) in conjunction with the Jet Propulsion Laboratory (JPL), North Carolina A&T and California State University of Los Angeles participated during the summer of 1996 in a prototype program known as Minority University Systems Engineering (MUSE). The program consisted of a ten week internship at JPL for students and professors of the three universities. The purpose of MUSE as set forth in the MUSE program review August 5, 1996 was for the participants to gain experience in the following areas: 1) Gain experience in a multi-disciplinary project; 2) Gain experience working in a culturally diverse atmosphere; 3) Provide field experience for students to reinforce book learning; and 4) Streamline the design process in two areas: make it more financially feasible; and make it faster.

  19. Length-weight relationship of the freshwater clam, Galatea paradoxa (born 1778) from the Volta Estuary, Ghana.

    Science.gov (United States)

    Obirikorang, K A; Adjei-Boateng, D; Madkour, H A; Amisah, S; Otchere, F A

    2013-02-15

    The length-weight relationship of the threatened freshwater clam, Galatea paradoxa (Born 1778) from the Volta Estuary, Ghana was studied over a two-year period, from March 2008 to February 2010, to aid in the development of stock assessment models for the sustainable management of the remaining clam stock. Data reported in this study were collected at monthly intervals and covered varying depths of the Estuary ranging from 0.5 to about 10 m. Overall, a total of 5276 clams with shell lengths ranging from 3.40 to 89.24 mm and total weight from 0.10 to 154.00 g were sampled during the study period. The length-weight relationships were highly significant (p < 0.0001) for all the months and the b-values ranged from 2.023 (January 2010) to 3.874 (June 2009). The calculated b-values indicated that clams exhibited different growth patterns at different periods but overall, the pooled samples of 5276 individuals exhibited an isometric growth pattern (b = 3.003). The observed monthly growth patterns exhibited by G. paradoxa appeared to be largely influenced by the reproductive cycle of the organism. During the periods leading to spawning, the clams generally exhibited positive allometric growth patterns (weight increasing faster than length) which appeared to be strongly linked to the build-up of proteins and carbohydrates in their tissues. Successive negative allometric growth patterns (length increasing faster relative to weight) were, however, observed from March to June 2008 and from December 2009 to February 2010, which are possibly indicative of the loss in tissue weight that occurs as a direct result of the spawning process. It will thus be suitable to institute a close season to coincide with the spawning period of the clams to avoid the harvesting of clams during the spawning period which will enhance future recruitment of the clam stock.

  20. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). SURF CLAM

    Science.gov (United States)

    1983-10-01

    invisible, outer, jellylike layer and mine surf clam gender (Ropes et al. the germinal vesicle (Ropes 1980). 1969). Male and female surf clams Longo...Jacobsen, M. K., and W. E. Old, Jr. Lindley, M. G., and R. S. Shallen- 1966. On the identity of Spisula berger. 1976, Purification and similis. Am...1966. A quantitative Masse, H. 1975. Feeding biotogy of .3-year-survey on the meiofauna Astropecten aranciacus. Cah , of known macrofauna communities

  1. On the feasibility of monitoring carbon monoxide in the lower troposphere from a constellation of northern hemisphere geostationary satellites: Global scale assimilation experiments (Part II)

    Science.gov (United States)

    Barré, Jérôme; Edwards, David; Worden, Helen; Arellano, Avelino; Gaubert, Benjamin; Da Silva, Arlindo; Lahoz, William; Anderson, Jeffrey

    2016-09-01

    This paper describes the second phase of an Observing System Simulation Experiment (OSSE) that utilizes the synthetic measurements from a constellation of satellites measuring atmospheric composition from geostationary (GEO) Earth orbit presented in part I of the study. Our OSSE is focused on carbon monoxide observations over North America, East Asia and Europe where most of the anthropogenic sources are located. Here we assess the impact of a potential GEO constellation on constraining northern hemisphere (NH) carbon monoxide (CO) using data assimilation. We show how cloud cover affects the GEO constellation data density with the largest cloud cover (i.e., lowest data density) occurring during Asian summer. We compare the modeled state of the atmosphere (Control Run), before CO data assimilation, with the known "true" state of the atmosphere (Nature Run) and show that our setup provides realistic atmospheric CO fields and emission budgets. Overall, the Control Run underestimates CO concentrations in the northern hemisphere, especially in areas close to CO sources. Assimilation experiments show that constraining CO close to the main anthropogenic sources significantly reduces errors in NH CO compared to the Control Run. We assess the changes in error reduction when only single satellite instruments are available as compared to the full constellation. We find large differences in how measurements for each continental scale observation system affect the hemispherical improvement in long-range transport patterns, especially due to seasonal cloud cover. A GEO constellation will provide the most efficient constraint on NH CO during winter when CO lifetime is longer and increments from data assimilation associated with source regions are advected further around the globe.

  2. Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

    Science.gov (United States)

    Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

    2016-12-01

    Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20–41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8–12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

  3. Effects of benzo(a)pyrene on differentially expressed genes and haemocyte parameters of the clam Venerupis philippinarum.

    Science.gov (United States)

    Liu, Na; Pan, Luqing; Gong, XiaoLi; Tao, Yanxia; Hu, Yanyan; Miao, Jingjing

    2014-03-01

    In this study a suppression subtractive hybridisation method was employed to identify differentially expressed genes of the clam Venerupis philippinarum exposed to benzo(a)pyrene (BaP). Nineteen known transcripts and seven predicted proteins were found from the subtractive cDNA library of the clam, which could provide more sequence information for further study. Seven of the differentially expressed genes were selected for mRNA expression analysis. Real-time PCR analysis revealed that the expression level of the selected cDNAs of clams was up-regulated to varying degrees by different concentration of BaP. They are suggested as potential molecular biomarkers for polycyclic aromatic hydrocarbons (PAHs) pollution monitoring in aquatic ecosystems. In addition, haemocyte parameters were also measured, and a decrease of total haemocyte counts and suppression of antibacterial and bacteriolytic activities were detected in BaP-stressed clams. We suggest that the modulation of the expression of the selected genes caused by PAHs probably leads to the disturbance of the immune defense of the clam. Meanwhile, the adverse effects of PAHs on haemocyte parameters caused the suppression of the immune defense and susceptibility to infectious diseases. Therefore, it is inferred that PAHs pollutants could interact with components of the immune system and interferes with defense functions of the clam V. philippinarum.

  4. The effectiveness of domestic cook on inactivation of murine norovirus in experimentally infected Manila clams (Ruditapes philippinarum).

    Science.gov (United States)

    Toffan, A; Brutti, A; De Pasquale, A; Cappellozza, E; Pascoli, F; Cigarini, M; Di Rocco, M; Terregino, C; Arcangeli, G

    2014-01-01

    The aim of this work was to evaluate the efficacy of domestic cooking in inactivating Manila clams experimentally infected with murine norovirus (MNV). A cooking pan was modified to enable electronic temperature probes to be positioned to record both flesh and environment temperature. Manila clams were infected with 10(4) TCID 50% ml(-1) of MNV. The infected whole-in-shell clams, divided into three replicates, were cooked on an electric stove, and groups of nine clams were removed from the pan at fixed intervals. Pools of three digestive glands were examined by virus isolation to ascertain residual viral load. Results showed that 10 min of cooking by a traditional domestic method at a temperature close to 100°C, for at least 2 min, can completely devitalize the MNV in infected clams. This is generally the time needed for the majority of valves to open up. At present, it is highly recommended to label all lagoon products as 'requiring cooking before consumption', but no specifications are given on how long and at what temperature they should be cooked. Our results can provide the consumer with useful indications on how to cook clams to prevent any risk of foodborne illness. © 2013 The Society for Applied Microbiology.

  5. Ground-based diffusion experiments on liquid Sn-In systems using the shear cell technique of the satellite mission Foton-M1.

    Science.gov (United States)

    Suzuki, Shinsuke; Kraatz, Kurt-Helmut; Frohberg, Günter

    2004-11-01

    This study reported in this paper was aimed at testing the shear cell that was developed for the satellite mission Foton-M1 to measure diffusion coefficients in liquid metals under microgravity (microg)-conditions. Thick Layer diffusion experiments were performed in the system Sn90In10 versus Sn under 1 g-conditions. For this system several microg-diffusion results are available as reference data. This combination provides a low, but sufficiently stable, density layering throughout the entire experiment, which is important to avoid buoyancy-driven convection. The experimental results were corrected for the influences of the shear-induced convection and mixing after the final shearing, both of which are typical for the shear cell technique. As the result, the reproducibility and the reliability of the diffusion coefficients in the ground-based experiments were within the limits of error of microg-data. Based on our results we discuss the necessary conditions to avoid buoyancy-driven convection.

  6. Effects of clam size, food type, sediment characteristic, and seawater carbonate chemistry on grazing capacity of Venus clam Cyclina sinensis (Gmelin, 1791)

    Science.gov (United States)

    Lin, Tingting; Zhou, Kai; Liu, Xin; Lai, Qifang; Zhang, Dong; Shi, Liyan

    2017-09-01

    Aquaculture in saline-alkaline water has a major problem: microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity (CA, 2.5, 10.0, and 20.0 meq/L) and pH (8.0, 8.5, and 9.0) on the grazing capacity (GC) of the clam Cyclina sinensis. Additionally, the effect of clam size (small, medium, and large) and microalgae species ( Nannochloropsis oculata, Chaetoceros müelleri, and Isochrysis galbana), and the effect of bottom sediment characteristic (mud, sandy mud, and muddy sand) and thickness (3 and 6 cm) were analyzed as well. The results show that the GC on I. galbana was the highest and small size had the maximum GC/ W ( W: wet weight including body and shells). No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC of C. sinensis was not greatly reduced in the treatments of pH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.

  7. Effects of clam size, food type, sediment characteristic, and seawater carbonate chemistry on grazing capacity of Venus clam Cyclina sinensis (Gmelin, 1791)

    Science.gov (United States)

    Lin, Tingting; Zhou, Kai; Liu, Xin; Lai, Qifang; Zhang, Dong; Shi, Liyan

    2016-10-01

    Aquaculture in saline-alkaline water has a major problem: microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity (CA, 2.5, 10.0, and 20.0 meq/L) and pH (8.0, 8.5, and 9.0) on the grazing capacity (GC) of the clam Cyclina sinensis. Additionally, the effect of clam size (small, medium, and large) and microalgae species (Nannochloropsis oculata, Chaetoceros müelleri, and Isochrysis galbana), and the effect of bottom sediment characteristic (mud, sandy mud, and muddy sand) and thickness (3 and 6 cm) were analyzed as well. The results show that the GC on I. galbana was the highest and small size had the maximum GC/W (W: wet weight including body and shells). No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC of C. sinensis was not greatly reduced in the treatments of pH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.

  8. The TAOS/STEP Satellite

    OpenAIRE

    Edwards, David; Hosken, Robert

    1995-01-01

    The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous N...

  9. The Dedicated Aerosol Retrieval Experiment (DARE): scientific requirements for a dedicated satellite instrument to measure atmospheric aerosols

    NARCIS (Netherlands)

    Decae, R.; Courrèges-Lacoste, G.B.; Leeuw, G. de

    2004-01-01

    DARE (Dedicated Aerosol Retrieval Experiment) is a study to design an instrument for accurate remote sensing of aerosol properties from space. DARE combines useful properties of several existing instruments like TOMS, GOME, ATSR and POLDER. It has a large wavelength range, 330 to 1000 nm, to discrim

  10. Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS experiment: design, execution and science overview

    Directory of Open Access Journals (Sweden)

    P. I. Palmer

    2013-02-01

    Full Text Available We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants using Aircraft and Satellites experiment, which has the overarching objective of understanding the chemical aging of airmasses that contain the emission products from seasonal boreal wildfires and how these airmasses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA over eastern Canada. The planned July 2010 deployment of the ARA was postponed by 12 months because of activities related to the dispersal of material emitted by the Eyjafjallajökull volcano. However, most other planned model and measurement activities, including ground-based measurements at the Dalhousie University Ground Station (DGS, enhanced ozonesonde launches, and measurements at the Pico Atmospheric Observatory in the Azores, went ahead and constituted phase A of the experiment. Phase B of BORTAS in July 2011 included the same measurements, but included the ARA, special satellite observations and a more comprehensive measurement suite at the DGS. The high-frequency aircraft data provided a comprehensive snapshot of the pyrogenic plumes from wildfires. The coordinated ground-based and sonde data provided detailed but spatially-limited information that put the aircraft data into context of the longer burning season. We coordinated aircraft vertical profiles and overpasses of the NASA Tropospheric Emission Spectrometer and the Canadian Atmospheric Chemistry Experiment. These space-borne data, while less precise than other data, helped to relate the two-week measurement campaign to larger geographical and longer temporal scales. We interpret these data using a range of chemistry models: from a near-explicit gas-phase chemical mechanism, which tests out understanding of the underlying chemical mechanism, to regional and global 3-D models

  11. Creep deformation and rupture behavior of CLAM steel at 823 K and 873 K

    Science.gov (United States)

    Zhong, Boyu; Huang, Bo; Li, Chunjing; Liu, Shaojun; Xu, Gang; Zhao, Yanyun; Huang, Qunying

    2014-12-01

    China Low Activation Martensitic (CLAM) steel is selected as the candidate structural material in Fusion Design Study (FDS) series fusion reactor conceptual designs. The creep property of CLAM steel has been studied in this paper. Creep tests have been carried out at 823 K and 873 K over a stress range of 150-230 MPa. The creep curves showed three creep regimes, primary creep, steady-state creep and tertiary creep. The relationship between minimum creep rate (ε˙min) and the applied stress (σ) could be described by Norton power law, and the stress exponent n was decreased with the increase of the creep temperature. The creep mechanism was analyzed with the fractographes of the rupture specimens which were examined by scanning electron microscopy (SEM). The coarsening of precipitates observed with transmission electron microscope (TEM) indicated the microstructural degradation after creep test.

  12. Microbiological composition of native and exotic clams from Tagus estuary: effect of season and environmental parameters.

    Science.gov (United States)

    Anacleto, Patrícia; Pedro, Sónia; Nunes, Maria Leonor; Rosa, Rui; Marques, António

    2013-09-15

    The influence of seasonal and environmental parameters on the occurrence of bacteria was investigated in two clam species (Venerupis pullastra and Ruditapes philippinarum), water and sediment from the Tagus estuary. Total viable counts (TVC), Escherichia coli, Salmonella spp. and Vibrio spp. were evaluated during one-year. Overall, significant seasonal variations were found in both sampling sites, especially for E. coli and Vibrio spp. levels. In summer, significantly higher Vibrio spp. levels were found in R. philippinarum and sediment samples, but not in V. pullastra clams and water samples. In contrast, significantly higher TVC and E. coli levels were observed in winter months in water and sediment samples. Salmonella spp. was generally isolated when higher levels of E. coli were detected, particularly in R. philippinarum. This study is useful for authorities to develop monitoring strategies for coastal contamination and to estimate human health risks associated with the consumption of bivalves. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Daily estimates of fire danger using multitemporal satellite MODIS data: the experience of FIRE-SAT in the Basilicata Region (Italy)

    Science.gov (United States)

    Lanorte, R.; Lasaponara, R.; De Santis, F.; Aromando, A.; Nole, G.

    2012-04-01

    Daily estimates of fire danger using multitemporal satellite MODIS data: the experience of FIRE-SAT in the Basilicata Region (Italy) A. Lanorte, F. De Santis , A. Aromando, G. Nolè, R. Lasaponara, CNR-IMAA, Potenza, Italy In the recent years the Basilicata Region (Southern Italy) has been characterized by an increasing incidence of fire disturbance which also tends to affect protected (Regional and national parks) and natural vegetated areas. FIRE_SAT project has been funded by the Civil Protection of the Basilicata Region in order to set up a low cost methodology for fire danger/risk monitoring based on satellite Earth Observation techniques. To this aim, NASA Moderate Resolution Imaging Spectroradiometer (MODIS) data were used. The spectral capability and daily availability makes MODIS products especially suitable for estimating the variations of fuel characteristics. This work presents new significant results obtained in the context of FIRE-SAT project. In order to obtain a dynamical indicator of fire susceptibility based on multitemporal MODIS satellite data, up-datable in short-time periods (daily), we used the spatial/temporal variations of following parameters: (1) Relative Greenness Index (2) Live and dead fuel moisture content (3) Temperature In particular, the dead fuel moisture content is a key factor in fire ignition. Dead fuel moisture dynamics are significantly faster than those observed for live fuel. Dead fine vegetation exhibits moisture and density values dependent on rapid atmospheric changes and strictly linked to local meteorological conditions. For this reason, commonly, the estimation of dead fuel moisture content is based on meteorological variables. In this study we propose to use MODIS data to estimate meteorological data (specifically Relative Humidity) at an adequate spatial and temporal resolution. The assessment of dead fuel moisture content plays a decisive role in determining a fire dynamic danger index in combination with other

  14. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    Science.gov (United States)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  15. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  16. Multi-species generalist predation on the stochastic harvested clam Tivela mactroides (Mollusca, Bivalvia)

    Science.gov (United States)

    Turra, Alexander; Fernandez, Wellington S.; Bessa, Eduardo; Santos, Flavia B.; Denadai, Márcia R.

    2015-12-01

    Top-down control is an important force modulating the abundance of prey and structuring marine communities. The harvested trigonal clam Tivela mactroides is hypothesized to be part of the diet of a variety of marine organisms, with its stock influencing predator abundance and being influenced by them. Here we analyzed the diet of potential predators of T. mactroides in Caraguatatuba Bay, northern coast of São Paulo State, Brazil, to identify the main consumers of this marine resource, and also to address the importance of this clam in the diet of each predator. Samples were taken year-round by trawls; all specimens collected were identified and measured and the food items identified and quantified. Twenty-one species consumed T. mactroides, whose importance in the diet varied greatly in both the volume ingested and the frequency of occurrence (pompano Trachinotus carolinus > blue crab Callinectes danae > starfish Astropecten marginatus). Top-down influence on T. mactroides was also dependent on the abundance of consumers (yellow catfish Cathorops spixii > rake stardrum Stellifer rastrifer > barred grunt Conodon nobilis > A. marginatus). Considering the mean volume ingested, the frequency of occurrence of T. mactroides in the diet, and the relative abundance of consumers, the predators that most influenced T. mactroides were T. carolinus, A. marginatus, and C. danae, in decreasing order. Large numbers of small-sized individuals of T. mactroides (<10 mm) were generally preyed upon by A. marginatus, which may have a stronger effect on clam abundance in comparison to C. danae and T. carolinus, which preyed upon larger clams. In conclusion, the results of this study indicate that predators' consumption of T. mactroides in Caraguatatuba Bay can influence its stocks, mainly due to the type and/or abundance of predator species, the volume and number of individuals of T. mactroides preyed upon, and the temporal variations in the abundance of predators.

  17. Blood clams community (Anadara granoasa in The Eastern Coastal Waters of Banyuasin Regency South Sumatera

    Directory of Open Access Journals (Sweden)

    Rini Setianingsih

    2016-04-01

    Full Text Available Abstract: This research aimed to study existence of blood clams population and the environmental factors that affect them. This research was conducted in the coastal waters of Banyuasin in February 2015. The blood clamp sample was collected using Ekman Grab at low tide. From the observation in the research site, the highest population density was 60 ind/m2 with clay substrate texture, while the lowest density was 20 ind/m2 on the dusty clay substrate. Blood clams population was not found on the sand substrate texture station. Morphometric data showed that the blood clam population in the research site, including the medium category with b < 3 growth pattern (allometric negative. The results of PCA analysis proved that the habitat texture and sediment organic habitats were dominant factors besides the chemical physics environmental factors of the waters (temperature, salinity, pH. Keywords: Blood clams, density, morphometric, PCA Abstrak (Indonesian: Penelitian ini bertujuan untuk mempelajari keberadaan populasi kerang-darah dan faktor lingkungan yang mempengaruhinya. Penelitian ini dilakukan di perairan pesisir Banyuasin pada bulan Februari 2015. Sampel kerang-darah diambil dengan mengunakan Ekman Grab pada saat air surut. Dari hasil pengamatan pada lokasi penelitian, kepadatan populasi kerang-darah tertinggi adalah 60 ind/m2 dengan tekstur substrat lempung, sedangkan kepadatan terendah adalah 20 ind/m2 pada substrat lempung berdebu. Populasi kerang-darah tidak ditemukan pada stasiun dengan tekstur substrat pasir. Data morfometrik menunjukan bahwa populasi kerang-darah di lokasi penelitian termasuk kategori sedang dengan pola pertumbuhan b < 3 (allometrik negatif. Hasil analisis PCA membuktikan bahwa tekstur habitat dan bahan organik sedimen merupakan faktor dominan disamping faktor lingkungan fisika kimia perairan (suhu, salinitas, pH. Kata kunci: Kerang-darah, kepadatan, morfometrik, PCA

  18. Transovarial inheritance of endosymbiotic bacteria in clams inhabiting deep-sea hydrothermal vents and cold seeps.

    Science.gov (United States)

    Cary, S C; Giovannoni, S J

    1993-06-15

    Vesicomyid clams are conspicuous fauna at many deep-sea hydrothermal-vent and cold-seep habitats. All species examined have specialized gill tissue harboring endosymbiotic bacteria, which are thought to provide the hosts' sole nutritional support. In these species mechanisms of symbiont inheritance are likely to be key elements of dispersal strategies. These mechanisms have remained unresolved because the early life stages are not available for developmental studies. A specific 16S rRNA-directed oligodeoxynucleotide probe (CG1255R) for the vesocomyid endosymbionts was used in a combination of sensitive hybridization techniques to detect and localize the endosymbionts in host germ tissues. Symbiont-specific polymerase chain reaction amplifications, comparative gene sequencing, and restriction fragment length polymorphisms were used to detect and confirm the presence of symbiont target in tissue nucleic acid extracts. Nonradioactive in situ hybridizations were used to resolve the position of the bacterial endosymbionts in host cells. Symbiont 16S rRNA genes were consistently amplified from the ovarial tissue of three species of vesicomyid clams: Calyptogena magnifica, C. phaseoliformis, and C. pacifica. The nucleotide sequences of the genes amplified from ovaries were identical to those from the respective host symbionts. In situ hybridizations to CG1255R labeled with digoxigenin-11-dUTP were performed on ovarial tissue from each of the vesicomyid clams. Detection of hybrids localized the symbionts to follicle cells surrounding the primary oocytes. These results suggest that vesicomyid clams assure successful, host-specific inoculation of all progeny by using a transovarial mechanism of symbiont transmission.

  19. Effect of tantalum content on microstructure and tensile properties of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Xiangwei [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zhao, Yanyun [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2016-03-15

    Highlights: • With the increase of Ta content, the grain size decreased firstly, and then leveled off when Ta content was higher than 0.15 wt%. • The content of Ta-riched MX particles increased with Ta content increasing, and the Cr-riched M{sub 23}C{sub 6} carbides reversed. • CLAM steel with Ta content of 0.027 wt% had the highest strength, but the difference in strength of the four ingots was little. - Abstract: Four ingots of China Low Activation Martensitic (CLAM) steel with different Tantalum (Ta) contents of 0.027 wt%, 0.078 wt%, 0.15 wt% and 0.18 wt%, respectively, were produced by vacuum induction furnace. Microstructure observation and tensile tests were performed to make clear the effect of Ta content on the microstructure and properties of CLAM steel. Experimental results showed that the content of Ta-riched MX particles increased with Ta content increasing from 0.027 wt% to 0.18 wt%, and the Cr-riched M{sub 23}C{sub 6} carbides reversed. Meanwhile, the grain size became finer with the increase of Ta content. However, the effect of Ta content on grain size refinement weakened when Ta content was higher than 0.15 wt% in this study. Both the grain size and precipitates could affect the tensile properties of the four ingots. The precipitation strengthening of Cr-riched M{sub 23}C{sub 6} carbides was considered to be the main possible reason that CLAM steel with Ta content of 0.027 wt% had the highest strength. In general, there was little difference in strength of the four ingots with the change of Ta content.

  20. Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) experiment: design, execution and science overview

    Science.gov (United States)

    Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Bernath, P. F.; Duck, T. J.; Waugh, D. L.; Tarasick, D. W.; Andrews, S.; Aruffo, E.; Bailey, L. J.; Barrett, E.; Bauguitte, S. J.-B.; Curry, K. R.; Di Carlo, P.; Chisholm, L.; Dan, L.; Forster, G.; Franklin, J. E.; Gibson, M. D.; Griffin, D.; Helmig, D.; Hopkins, J. R.; Hopper, J. T.; Jenkin, M. E.; Kindred, D.; Kliever, J.; Le Breton, M.; Matthiesen, S.; Maurice, M.; Moller, S.; Moore, D. P.; Oram, D. E.; O'Shea, S. J.; Owen, R. C.; Pagniello, C. M. L. S.; Pawson, S.; Percival, C. J.; Pierce, J. R.; Punjabi, S.; Purvis, R. M.; Remedios, J. J.; Rotermund, K. M.; Sakamoto, K. M.; da Silva, A. M.; Strawbridge, K. B.; Strong, K.; Taylor, J.; Trigwell, R.; Tereszchuk, K. A.; Walker, K. A.; Weaver, D.; Whaley, C.; Young, J. C.

    2013-07-01

    We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada, based out of Halifax, Nova Scotia. Atmospheric ground-based and sonde measurements over Canada and the Azores associated with the planned July 2010 deployment of the ARA, which was postponed by 12 months due to UK-based flights related to the dispersal of material emitted by the Eyjafjallajökull volcano, went ahead and constituted phase A of the experiment. Phase B of BORTAS in July 2011 involved the same atmospheric measurements, but included the ARA, special satellite observations and a more comprehensive ground-based measurement suite. The high-frequency aircraft data provided a comprehensive chemical snapshot of pyrogenic plumes from wildfires, corresponding to photochemical (and physical) ages ranging from 45 sr 10 days, largely by virtue of widespread fires over Northwestern Ontario. Airborne measurements reported a large number of emitted gases including semi-volatile species, some of which have not been been previously reported in pyrogenic plumes, with the corresponding emission ratios agreeing with previous work for common gases. Analysis of the NOy data shows evidence of net ozone production in pyrogenic plumes, controlled by aerosol abundance, which increases as a function of photochemical age. The coordinated ground-based and sonde data provided detailed but spatially limited information that put the aircraft data into context of the longer burning season in the boundary layer. Ground-based measurements of

  1. Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS experiment: design, execution and science overview

    Directory of Open Access Journals (Sweden)

    P. I. Palmer

    2013-07-01

    Full Text Available We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA over eastern Canada, based out of Halifax, Nova Scotia. Atmospheric ground-based and sonde measurements over Canada and the Azores associated with the planned July 2010 deployment of the ARA, which was postponed by 12 months due to UK-based flights related to the dispersal of material emitted by the Eyjafjallajökull volcano, went ahead and constituted phase A of the experiment. Phase B of BORTAS in July 2011 involved the same atmospheric measurements, but included the ARA, special satellite observations and a more comprehensive ground-based measurement suite. The high-frequency aircraft data provided a comprehensive chemical snapshot of pyrogenic plumes from wildfires, corresponding to photochemical (and physical ages ranging from 45 sr 10 days, largely by virtue of widespread fires over Northwestern Ontario. Airborne measurements reported a large number of emitted gases including semi-volatile species, some of which have not been been previously reported in pyrogenic plumes, with the corresponding emission ratios agreeing with previous work for common gases. Analysis of the NOy data shows evidence of net ozone production in pyrogenic plumes, controlled by aerosol abundance, which increases as a function of photochemical age. The coordinated ground-based and sonde data provided detailed but spatially limited information that put the aircraft data into context of the longer burning season in the boundary layer. Ground

  2. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    Science.gov (United States)

    Dubousquet, Vaimiti; Gros, Emmanuelle; Berteaux-Lecellier, Véronique; Viguier, Bruno; Raharivelomanana, Phila; Bertrand, Cédric; Lecellier, Gaël J.

    2016-01-01

    ABSTRACT Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA), which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA) diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress. PMID:27543058

  3. Occurrence of diarrhetic shellfish poisoning (DSP) toxins in clams (Ruditapes decussatus) from Tunis north lagoon.

    Science.gov (United States)

    Armi, Zina; Turki, Souad; Trabelsi, Elbahri; Ceredi, Alfiero; Riccardi, Elena; Milandri, Anna

    2012-08-01

    The main diarrhetic shellfish toxins, okadaic acid (OA) and dinophysistoxin-1, 2 (DTX-2, 2) were detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as pyrenacyl esters in clams (Ruditapes decussatus) collected in Tunis north lagoon from January 2007 to June 2008. Sample analyses by LC-MS/MS displayed OA and related congeners (DTX-2, 2) with a highest detected level of 21 μg OA eq/kg shellfish meat for the samples of January 2007. Nevertheless, all samples were MBA negative. During the study period, potentially toxic dinoflagellate Dinophysis sacculus was recorded all year, blooming at different times. Highest concentrations were recorded during January 2007 with 4.6 × 10(4) cells per liter and 4.10(4) cells per liter in the northern and southern districts, respectively. Results show that there is no significant correlation between D. sacculus densities in water column and diarrhetic shellfish poisoning (DSP) toxins concentrations unregistered in clams. These data reveal that DSP toxicity in clams of Tunis north lagoon is low according to European regulatory limit (160 μg OA eq/kg shellfish meat). However, a potential threat, in this area, is represented by DSP toxic species as D. sacculus and provides grounds for widen and reinforcing sanitary control of the phycotoxin measures in the region.

  4. Role of neuropeptide F in regulating filter feeding of Manila clam, Ruditapes philippinarum.

    Science.gov (United States)

    Wang, Xin; Miao, Jingjing; Liu, Peipei; Pan, Luqing

    2017-03-01

    Endogenous signals which may be involved in the regulation of filter feeding in bivalves have never been examined. NPY/NPF homologue has been proved to play an important role in the regulation of food intake in vertebrate and several invertebrates. In this study, a NPF homologue was cloned from visceral ganglia of clam Ruditapes philippinarum. The full-length cDNA sequence was 892bp in length and encoded a precursor of 82 amino acid residues. We then examined the effects of fasting and refeeding on the filtration rates (FR), plasma glucose concentration (PGC), 5-HT, DA and the expression level of the rp-NPF and insulin transcript. The mRNA expression level of rp-NPF in visceral ganglion was increased during fasting, and rose to highest level on 72h after starvation and declined immediately after food had been supplied. Hemocoel injection of rp-NPF(5μg/g)significantly increased FR of clams within 2h. Compared to the controls, a significant increase in insulin mRNA levels was observed at 8h after injection. Contents of 5-HT and DA also increased in the 5μg/grp-NPF administrated clams at 8 and 24h after injection. These results suggest that, similar to vertebrates, NPF, insulin, 5-HT and DA may play a role in the regulation of feeding in R. philippinarum. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Enzyme responses and lipid peroxidation in gills and hepatopancreas of clam Mactra vereformis, following cadmium exposure

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaoyu; YANG Hongsheng; LIU Guangbin; WANG Qing

    2011-01-01

    To assess the toxicity of heavy metal pollution to marine intertidal shellfish,enzymatic responses and lipid peroxidation were investigated in the clam Mactra vereformis exposed to cadmium under laboratory conditions.Three antioxidant enzymes (superoxide dismutase,SOD; catalase,CAT;glutathione peroxidase,GPx),two immune defense enzymes (acid phosphatase,ACP; alkaline phosphatase,ALP),and one lipid peroxidation product (malondialdehyde,MDA) were measured in the gills and the hepatopancreas of the clam exposed to 0,25,75,and 125 μg/L cadmium for 0,1,3,5,and 7 d.The results show that the concentrations of antioxidant enzymes in the organs soared to a peak value on the first day and then decreased afterwards in most cases.CAT and GPx activities in the hepatopancreas were higher than in the gills,but the SOD activity was lower in the bepatopancreas.ACP activity was unchanged until Day 3 in the hepatopancreas and until Day 5 in gills,when it began to increase.ALP activity showed no significant relationship with Cd treatment.MDA concentrations increased in the two tissues after Cd exposure,peaked on Day 3 in gills,and on Day 5 in hepatopancreas.These observations show that changes in the activities of antioxidant enzymes and ACP reflect the time course of oxidative stress in the clam caused by Cd,and could be used as potential biomarkers for ecotoxicological bioassays of heavy metals.

  6. Modeling habitat suitability of the invasive clam Corbicula fluminea in a Neotropical shallow lagoon, southern Brazil

    Directory of Open Access Journals (Sweden)

    T. C. L. Silveira

    Full Text Available Abstract This study aimed to model the habitat suitability for an invasive clam Corbicula fluminea in a coastal shallow lagoon in the southern Neotropical region (–30.22, –50.55. The lagoon (19km2, maximum deep 2.5m was sampled with an Ekman dredge in an orthogonal matrix comprising 84 points. At each sampling point, were obtained environmental descriptors as depth, organic matter content (OMC, average granulometry (Avgran, and the percentage of sand (Pcsand. Prediction performance of Generalized Linear Models (GLM, Generalized Additive Models (GAM and Boosted Regression Tree (BRT were compared. Also, niche overlapping with other native clam species (Castalia martensi, Neocorbicula limosa and Anodontites trapesialis was examined. A BRT model with 1400 trees was selected as the best model, with cross-validated correlation of 0.82. The relative contributions of predictors were Pcsand-42.6%, OMC-35.8%, Avgran-10.9% and Depth-10.8%. Were identified that C. fluminea occur mainly in sandy sediments with few organic matter, in shallow areas nor by the shore. The PCA showed a wide niche overlap with the native clam species C. martensi, N. limosa and A. trapesialis.

  7. Physiological and biochemical responses of three Veneridae clams exposed to salinity changes.

    Science.gov (United States)

    Carregosa, Vanessa; Velez, Cátia; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2014-01-01

    Given their global importance, coastal marine environments are a major focus of concern regarding the potential impacts of climate change, namely due to alterations in seawater salinity. It is known that environmental characteristics, such as salinity, affect immune and physiological parameters of bivalves. Nevertheless, scarce information is available concerning the biochemical alterations associated with salinity changes. For this reason, the present work aimed to evaluate the biochemical responses of three venerid clam species (Venerupis decussata, Venerupis corrugata, Venerupis philippinarum) submitted to salinity changes. The effects on the native (V. decussata and V. corrugata) and invasive (V. philippinarum) species collected from the same sampling site and submitted to the same salinity gradient (0 to 42g/L) were compared. The results obtained demonstrated that V. corrugata is the most sensitive species to salinity changes and V. decussata is the species that can tolerate a wider range of salinities. Furthermore, our work showed that clams under salinity associated stress can alter their biochemical mechanisms, such as increasing their antioxidant defenses, to cope with the higher oxidative stress resulting from hypo and hypersaline conditions. Among the physiological and biochemical parameters analyzed (glycogen and protein content; lipid peroxidation levels, antioxidant enzymes activity; total, reduced and oxidized glutathione) Catalase (CAT) and especially superoxide dismutase (SOD) showed to be useful biomarkers to assess salinity impacts in clams.

  8. Larval and juvenile growth performance of Manila clam hybrids of two full-sib families

    Science.gov (United States)

    Huo, Zhongming; Yan, Xiwu; Zhao, Liqiang; Liang, Jian; Yang, Feng; Zhang, Guofan

    2015-06-01

    In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam ( Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A × ♀B ( Hp varied between 10.41% and 68.27%) displayed larger heterosis than ♂B × ♀A ( Hp varied between 1.89% and 32.33%) did, suggesting that ♂A × ♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability (GCA), special combining ability (SCA) and interaction (I) were significant in shell length (P larvae and juveniles. The GCA for shell length of ♂A × ♀B was higher than that of ♂B × ♀A at both larval and juvenile stages. This confirmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.

  9. Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress

    Directory of Open Access Journals (Sweden)

    Vaimiti Dubousquet

    2016-10-01

    Full Text Available Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA, which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA diversity were accompanied by an upregulation of genes involved in lipids and ROS pathways. Finally, our microscopic analysis revealed that for the giant clam's symbiont, Symbiodinium, thermal stress led to two sequential cell death processes. Our data suggests that the degradation of Symbiodinium cells could provide an additional source of energy to T. maxima in response to heat stress.

  10. Influence of thermal aging on microstructure and mechanical properties of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lixin, E-mail: lxhuang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Hu, Xue; Yang, Chunguang; Yan, Wei [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Xiao, Furen [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Shan, Yiyin, E-mail: yyshan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yang, Ke [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2013-11-15

    In order to investigate the influence of thermal aging on microstructure and mechanical properties of CLAM (China low activation martensitic) steel, a comparison study was made on the as-tempered and the aged steels. The tempered CLAM steels were subjected to aging treatment at 600 °C for 1100 h and 3000 h, and at 650 °C for 1100 h, respectively. The changes of microstructure were characterized by both transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanical properties were evaluated by Charpy impact, tensile and Vickers hardness tests. The upper shelf energy (USE) of the thermal aged CLAM steel decreased with the extension of aging time, while the yield strength changed slightly. After long-term thermal aging, the MX type precipitates remained stable. The coarsening of M{sub 23}C{sub 6} and the formation of Laves phase were confirmed by scanning/transmission electron microscopes. The Laves phase was the main factor leading to the increase of DBTT.

  11. Influence of thermal aging on microstructure and mechanical properties of CLAM steel

    Science.gov (United States)

    Huang, Lixin; Hu, Xue; Yang, Chunguang; Yan, Wei; Xiao, Furen; Shan, Yiyin; Yang, Ke

    2013-11-01

    In order to investigate the influence of thermal aging on microstructure and mechanical properties of CLAM (China low activation martensitic) steel, a comparison study was made on the as-tempered and the aged steels. The tempered CLAM steels were subjected to aging treatment at 600 °C for 1100 h and 3000 h, and at 650 °C for 1100 h, respectively. The changes of microstructure were characterized by both transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanical properties were evaluated by Charpy impact, tensile and Vickers hardness tests. The upper shelf energy (USE) of the thermal aged CLAM steel decreased with the extension of aging time, while the yield strength changed slightly. After long-term thermal aging, the MX type precipitates remained stable. The coarsening of M23C6 and the formation of Laves phase were confirmed by scanning/transmission electron microscopes. The Laves phase was the main factor leading to the increase of DBTT.

  12. Short-term acute hypercapnia affects cellular responses to trace metals in the hard clams Mercenaria mercenaria.

    Science.gov (United States)

    Ivanina, Anna V; Beniash, Elia; Etzkorn, Markus; Meyers, Tiffany B; Ringwood, Amy H; Sokolova, Inna M

    2013-09-15

    Estuarine and coastal habitats experience large fluctuations of environmental factors such as temperature, salinity, partial pressure of CO2 ( [Formula: see text] ) and pH; they also serve as the natural sinks for trace metals. Benthic filter-feeding organisms such as bivalves are exposed to the elevated concentrations of metals in estuarine water and sediments that can strongly affect their physiology. The effects of metals on estuarine organisms may be exacerbated by other environmental factors. Thus, a decrease in pH caused by high [Formula: see text] (hypercapnia) can modulate the effects of trace metals by affecting metal bioavailability, accumulation or binding. To better understand the cellular mechanisms of interactions between [Formula: see text] and trace metals in marine bivalves, we exposed isolated mantle cells of the hard clams (Mercenaria mercenaria) to different levels of [Formula: see text] (0.05, 1.52 and 3.01 kPa) and two major trace metal pollutants - cadmium (Cd) and copper (Cu). Elevated [Formula: see text] resulted in a decrease in intracellular pH (pHi) of the isolated mantle cells from 7.8 to 7.4. Elevated [Formula: see text] significantly but differently affected the trace metal accumulation by the cells. Cd uptake was suppressed at elevated [Formula: see text] levels while Cu accumulation has greatly accelerated under hypercapnic conditions. Interestingly, at higher extracellular Cd levels, labile intracellular Cd(2+) concentration remained the same, while intracellular levels of free Zn(2+) increased suggesting that Cd(2+) substitutes bound Zn(2+) in these cells. In contrast, Cu exposure did not affect intracellular Zn(2+) but led to a profound increase in the intracellular levels of labile Cu(2+) and Fe(2+). An increase in the extracellular concentrations of Cd and Cu led to the elevated production of reactive oxygen species under the normocapnic conditions (0.05 kPa [Formula: see text] ); surprisingly, this effect was mitigated in

  13. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  14. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  15. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Science.gov (United States)

    Watson, Sue-Ann

    2015-01-01

    Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 μatm) and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1). Elevated CO2 projected for the end of this century (~650 and ~950 μatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  16. Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

    Directory of Open Access Journals (Sweden)

    Sue-Ann Watson

    Full Text Available Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2 (control ~400, mid ~650 and high ~950 μatm and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1. Elevated CO2 projected for the end of this century (~650 and ~950 μatm reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

  17. Assimilation of cadmium, chromium, and zinc by the green mussel Perna viridis and the clam Ruditapes philippinarum

    Energy Technology Data Exchange (ETDEWEB)

    Chong, K.; Wang, W.X.

    2000-06-01

    The green mussel Perna viridis and the clam Ruditapes philippinarum have been frequently used as biomonitors of coastal contamination in subtropical and tropical waters, yet the physiological processes controlling metal uptake in these bivalves are unknown. Assimilation efficiency (AE) is an important physiological parameter quantifying metal bioavailability from ingested food. The authors determined the AEs of Cd, CR, and Zn in these bivalves feeding on five species of phytoplankton and one natural section. The influences of the cytoplasmic distribution of metals in the algal cells and the digestive physiology of bivalves on metal AEs were also examined. Among the three metals, Zn was generally assimilated at the highest efficiency, i.e., 21 to 36% in the mussels and 29 to 59% in the clams. Cr was the least assimilated metal, with AEs being 10 to 16% in the mussels and 11 to 24% in the clams. The AEs of Cd and Zn in the clams were 1.8 to 4.7 and 1.1 to 1.9 times higher, respectively, than the AEs in the mussels. Assimilation efficiencies of Cr were, however, comparable between the mussels and the clams. A positive significant relationship between the metal AE and the percent of metals in the algal cytoplasm was found only for Cd in the clams, suggesting that Cd fractionation in the algal cells influenced its assimilation. No significant relationship, however, was found for other metals in both bivalves. A significant relationship between Cr-assimilation efficiency and gut passage time (GPT) was documented in the mussels, indicating a higher assimilation when Cr was retained longer in the gut. There was also significant correlation of metal AEs among the three metals, which were probably subjected to the same digestive pathway in the bivalves. Their study demonstrated that both the green mussels and the clams were able to accumulate metals from ingested food source, and food quality appeared to have different effects on metal assimilation in different bivalve

  18. Measuring the economic value of alternative clam fishing management practices in the Venice Lagoon: results from a conjoint valuation application

    Science.gov (United States)

    Nunes, Paulo A. L. D.; Rossetto, Luca; de Blaeij, Arianne

    2004-11-01

    This article focuses on the economic valuation of alternative clam management practices in the Venice Lagoon. The proposed valuation method is characterized by the design of a survey questionnaire applied to the fishermen population. In each questionnaire, two fishing alternatives are described. The respondent is asked to choose one of them. This valuation method, referred in the article as conjoint valuation, gives sufficient flexibility to set, alter, and combine the valuation of different clam management practices. Furthermore, this approach presents an important advantage to the well-known contingent valuation method since it makes the monetary valuation of each management attribute possible. Estimation results show that all three attributes used in the questionnaire to describe and value different clam management practices—price of the annual permit and fishing technological system—are statistically robust, indicating that fishermen bear a utility change whenever these attributes change. In particular, fishermen's willingness to pay for a larger clam fishing area ranges between 568 and 811 € per year. In addition, an individual's willingness to pay for a fishing practice exclusively based on the vibrant rake system ranges between 1005 and 2456 €. Finally, the adoption of a clam fish management practice in the Venice Lagoon that is exclusively based on the use of manual rakes, which is associated with the lowest damage to the lagoon ecosystem, will represent a welfare loss of 5904 € per fisherman per year. Combining such a value estimate with the total number of fishermen currently operating in the Lagoon of Venice, the welfare loss associated with the adoption of this type of clam management policy amounts to 11.8 € million per year. This figure can be regarded as an upper bound to the cost of implementation of a clam fishing system anchored in the use of manual, ecosystem friendly rakes.

  19. Comparisons between buoy-observed, satellite-derived, and modeled surface shortwave flux over the subtropical North Atlantic during the Subduction Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Waliser, Duane E. [Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook (United States); Weller, Robert A. [Woods Hole Oceanographic Institution, Woods Hole, Massachusetts (United States); Cess, Robert D. [Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook (United States)

    1999-12-27

    Two years of surface shortwave flux data, from five buoys in the subtropical North Atlantic Ocean during the Subduction Experiment, were used to examine shortwave absorption in the atmosphere, and its partitioning between the clear and cloudy sky. Robust methods were used to isolate the clear-sky shortwave observations so that they could be directly compared to values derived using a single-column version of the National Center for Atmospheric Research Community Climate Model radiation code. The model-derived values agreed with the observations to within 0.5% mean relative error. Additional analysis showed that the model-data clear-sky surface shortwave differences showed no systematic relationship with respect to column water vapor amount. These results indicate that clear-sky absorption of shortwave radiation appears to be well modeled by current theory. Model-derived clear-sky surface shortwave values were combined with the observed (all-sky) values to determine the surface shortwave cloud forcing. The mean of these series were combined with 5-year mean Earth Radiation Budget Experiment derived top of the atmosphere (TOA) cloud forcing values to estimate the surface to TOA cloud forcing ratio. The resulting values range between 1.25 and 1.59. These values, along with the agreement between modeled and observed clear-sky surface shortwave, support the suggestion that our current theoretical radiative transfer models do not properly account for the amount of shortwave energy absorbed by the cloudy atmosphere. Mean values from the 2-year shortwave flux time series were compared to mean values from two climatologies derived from bulk parameterizations that utilize ship-based cloud reports. These comparisons show that the Oberhuber climatology underestimates the surface shortwave flux by {approx}20% ({approx}40 W m-2), while the Esbensen and Kushnir climatology underestimates the flux by {approx}4% ({approx}8 W m-2). The observed mean values were also compared to five

  20. Neptunomonas concharum sp. nov., isolated from a dead ark clam, and emended description of the genus Neptunomonas.

    Science.gov (United States)

    Lee, Hae-Won; Shin, Na-Ri; Lee, Jina; Roh, Seong Woon; Whon, Tae Woong; Bae, Jin-Woo

    2012-11-01

    A novel Gram-staining-negative, facultatively anaerobic, motile and rod-shaped bacterium, designated strain LHW37(T), was isolated from a dead ark clam collected on the south coast of Korea. The novel strain grew optimally at 37 °C, at pH 7.0-8.0 and with 2% (w/v) NaCl. The predominant cellular fatty acids were C(18:1)ω7c and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH). The major isoprenoid quinone was ubiquinone-8 (Q-8) and the predominant polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Neptunomonas japonica JAMM 0745(T) (97.1% sequence similarity). The genomic DNA G+C content of strain LHW37(T) was 48.2 mol%. The DNA-DNA relatedness values recorded in hybridization experiments between the novel strain and its closest known relative were ≤ 18%. Based on the phenotypic, genotypic and phylogenetic data, strain LHW37(T) represents a novel species belonging to the genus Neptunomonas for which the name Neptunomonas concharum sp. nov. is proposed. The type strain is LHW37(T) (=KACC 15543(T) =JCM 17730(T)). An emended description of the genus Neptunomonas is also provided.

  1. Validation of MPI-ESM Decadal Hindcast Experiments with Terrestrial Water Storage Variations as Observed by the GRACE Satellite Mission

    Directory of Open Access Journals (Sweden)

    Liangjing Zhang

    2016-12-01

    Full Text Available Time-variations in the gravity field as observed by the GRACE mission provide for the first time quantitative estimates of the terrestrial water storage (TWS at monthly resolution over one decade (2002–2011. TWS from GRACE is applied here to validate three different ensemble sets of decadal hindcasts performed with the coupled climate model MPI-ESM within the German research project MiKlip. Those experiments differ in terms of the applied low (LR and medium (MR spatial resolution configuration of MPI-ESM, as well as by the applied ensemble initialization strategy, where ocean-only (b0 is replaced by atmosphere and ocean (b1 anomaly initialization. Moderately positive skill scores of the initialized hindcasts are obtained both with respect to the zero anomaly forecast and the uninitialized projections in particular for lead year 1 in moderate to high latitudes of the Northern Hemisphere. Skill scores gradually increase when moving from b0-LR to b1-LR, and less prominent also for b1-LR to b1-MR, thereby documenting improvements of the MPI-ESM decadal climate prediction system during the most recent years.

  2. Satellite Teleconferencing in the Caribbean.

    Science.gov (United States)

    Sankar, Hollis C.

    1985-01-01

    Discusses the need for, and the development, use, and future trends of, the University of the West Indies Distance Teaching Experiment, which utilizes telephone and communications satellite technology teleconferencing to extend educational opportunities to the peoples of the Caribbean. (MBR)

  3. Characterization of a long-chain fatty acid-CoA ligase 1 gene and association between its SNPs and growth traits in the clam Meretrix meretrix.

    Science.gov (United States)

    Dai, Ping; Huan, Pin; Wang, Hongxia; Lu, Xia; Liu, Baozhong

    2015-07-25

    Long-chain fatty acid-CoA ligases (ACSLs) play crucial roles in fatty acid (FA) metabolism. They convert free long-chain FA into acyl-CoAs, which are key intermediates in both anabolic and catabolic pathways. A long-chain fatty acid-CoA ligase gene was cloned in the clam Meretrix meretrix (MmeACSL1), with a full-length cDNA of 1865 bp encoding 475 amino acids. Its expression was only detected in hepatopancreas by semi-quantitative reverse transcription PCR. Expression level of MmeACSL1 exhibited a significant increase in a starvation experiment (Pgrowth traits (Pgrowth-related (Pgrowth traits of M. meretrix.

  4. Purification and Characterization of Hemagglutinating Proteins from Poker-Chip Venus (Meretrix lusoria and Corbicula Clam (Corbicula fluminea

    Directory of Open Access Journals (Sweden)

    Chin-Fu Cheng

    2012-01-01

    Full Text Available Hemagglutinating proteins (HAPs were purified from Poker-chip Venus (Meretrix lusoria and Corbicula clam (Corbicula fluminea using gel-filtration chromatography on a Sephacryl S-300 column. The molecular weights of the HAPs obtained from Poker-chip Venus and Corbicula clam were 358 kDa and 380 kDa, respectively. Purified HAP from Poker-chip Venus yielded two subunits with molecular weights of 26 kDa and 29 kDa. However, only one HAP subunit was purified from Corbicula clam, and its molecular weight was 32 kDa. The two Poker-chip Venus HAPs possessed hemagglutinating ability (HAA for erythrocytes of some vertebrate animal species, especially tilapia. Moreover, HAA of the HAP purified from Poker-chip Venus was higher than that of the HAP of Corbicula clam. Furthermore, Poker-chip Venus HAPs possessed better HAA at a pH higher than 7.0. When the temperature was at 4°C–10°C or the salinity was less than 0.5‰, the two Poker-chip Venus HAPs possessed better HAA compared with that of Corbicula clam.

  5. Effect of post-weld heat treatment on the mechanical properties of CLAM/316L dissimilar joint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junyu [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Huang, Bo [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wu, Qingsheng, E-mail: qingsheng.wu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing; Huang, Qunying [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2015-11-15

    Highlights: • Dissimilar joints between CLAM and 316L steels welded by TIG were investigated. • After PWHTs, the hardening in HAZ on the CLAM steel side decreased remarkably. • Tempering at 740 °C for 2 h was considered as the preferable treatment rule. - Abstract: Dissimilar welding between China low activation martensitic (CLAM) steel and 316L austenitic stainless steel was investigated to achieve the reliable connection between test blanket modules (TBMs) and piping system in the international thermonuclear experimental reactor (ITER). The dissimilar joints were welded by tungsten inert gas (TIG) welding process with a filler material type-309. In order to stabilize the microstructure and improve the strength and toughness, post-weld heat treatments (PWHTs) of tempering at 740 °C, 780 °C and 820 °C, respectively, for 2 h were performed. The microstructure observation showed that tempering at 740 °C for 2 h was the preferable PWHT rule in this work. After the treatment, the hardening in heat affected zone (HAZ) on the CLAM steel side decreased remarkably. The tensile strength of the joint was roughly the same as that of the base metal. The impact toughness of HAZ on the CLAM steel side was 77% of that of the base metal. The absorbed energy of HAZ of 316L steel decreased by 93 J, and that of weld metal (WM) was 110 J after the treatment.

  6. Bioaccumulation of polychlorinated biphenyls and metals from contaminated sediment by freshwater prawns, Macrobrachium rosenbergii and clams, Corbicula fluminea

    Energy Technology Data Exchange (ETDEWEB)

    Tatem, H.E.

    1986-02-01

    Freshwater prawns, Macrobrachium rosenbergii, and clams, Corbicula Fluminea, were exposed for 48 or 50 days to three concentrations of a river sediment that contained environmental contaminants such as polychlorinated biphenyls (PCBs) and metals. The PCB sediment bioaccumulation factors (BAF) for prawns ranged from 0.11 to 0.90 for 1242 and 0.20 to 2.40 for 1254, and were highest for animals exposed to 10% sediment. Exposed clams also accumulated PCBs (1242 + 1254) from the sediment. Sediment BAFs for clams were 0.54 to 12.52 and were highest for animals exposed to 10% sediment. Analyses of clams for metals showed lead (Pb) in exposed animals at higher concentrations compared with controls. Bioaccumulation of Pb differed from PCB in that the Pb concentrations did not increase over time and concentrations were higher among animals exposed to 10% sediment compared to animals exposed to 100% sediment. Sediment 11-80 contained 99 mg/kg of Pb while exposed animals, at 48 days, contained approximately 2.2 mg/kg Pb. Analysis of clams for cadmium (Cd) showed exposed animals contained less Cd than controls.

  7. Filtration and respiration rates of the short-necked clam Paphia undulata (Born, 1778 (Mollusca, Pelecypoda: Veneridae under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Laureen Morillo Manalo

    2010-12-01

    Full Text Available The filtration and respiration rates of various size classes (35-39.99, 40-44.99,45-49.99, 50-54.99 and 55-59.99 mm of the short-necked clam Paphia undulata were measured in the laboratory. The effects of three light regimes (0 lux, 172.22 lux and 645.83 lux, three microalgal species (Isochrysis galbana, Tetraselmis tetrahele and Chaetoceros calcitrans and four microalgal concentrations (10, 25, 50 and 100 x 104 cells ml-1 on filtration rates were investigated. Mean filtration rate was highest (0.57 ± 0.04 Lh-1ind.-1 under total darkness. This can be attributed to the natural environment of this species which is characterized by silty substrate and low visibility. Filtration was also highest in the microalga Isochrysis galbana (0.67 ± 0.05. Rates initially increased from low to moderate microalgal concentrations (25 x 104 cells ml-1 and decreased at higher concentrations. Filtration generally decreased with increase in clam size. Light intensity, microalgal species and microalgal concentration showed significant effects on filtration. Respiration of fed clams was higher (0.138 ± 0.026 ml O2h-1ind.-1 than unfed clams (0.053± 0.025 ml O2h-1 nd.-1 and increased with clam size.

  8. A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Bonnail, Estefanía; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José Miguel; DelValls, T Ángel

    2017-09-15

    Lanthanide series have been used as a record of the water-rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments. Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3-8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (EMREE=0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative "bio-tool" for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. X-ray spectrophotometer SphinX and particle spectrometer STEP-F of the satellite experiment CORONAS-PHOTON. Preliminary results of the joint data analysis

    Science.gov (United States)

    Dudnik, O. V.; Podgorski, P.; Sylwester, J.; Gburek, S.; Kowalinski, M.; Siarkowski, M.; Plocieniak, S.; Bakala, J.

    2012-04-01

    A joint analysis is carried out of data obtained with the help of the solar X-ray SphinX spectrophotometer and the electron and proton satellite telescope STEP-F in May 2009 in the course of the scientific space experiment CORONAS-PHOTON. In order to determine the energies and particle types, in the analysis of spectrophotometer records data are used on the intensities of electrons, protons, and secondary γ-radiation, obtained by the STEP-F telescope, which was located in close proximity to the SphinX spectrophotometer. The identical reaction of both instruments is noted at the intersection of regions of the Brazilian magnetic anomaly and the Earth's radiation belts. It is shown that large area photodiodes, serving as sensors of the X-ray spectrometer, reliably record electron fluxes of low and intermediate energies, as well as fluxes of the secondary gamma radiation from construction materials of detector modules, the TESIS instrument complex, and the spacecraft itself. The dynamics of electron fluxes, recorded by the SphinX spectrophotometer in the vicinity of a weak geomagnetic storm, supplements the information about the processes of radial diffusion of electrons, which was studied using the STEP-F telescope.

  10. Novelty detection in time series of ULF magnetic and electric components obtained from DEMETER satellite experiments above Samoa (29 September 2009 earthquake region

    Directory of Open Access Journals (Sweden)

    M. Akhoondzadeh

    2013-01-01

    Full Text Available Using ULF (ultra low frequency measurements of magnetometer and ICE (Instrument Champ Electrique experiments on board the DEMETER satellite, possible irregularities in ULF magnetic and electric components have been surveyed in the vicinity of Samoa (29 September 2009 earthquake region. The data used in this paper cover the period from 1 August 2009 to 11 October 2009. The anomalous variations in magnetic components (Bx, By and Bz were clearly observed on 1 and 3 days before the event. It is seen that the periodic patterns of the magnetic components obviously changed prior to the earthquake. These unusual variations have been also observed in the variations of polarization index obtained from the magnetic components during the whole period at ~10:30 and ~22:30 LT. It is concluded that the polarization exhibits an apparent increase on 1 and 3 days preceding the earthquake. These observed unusual disturbances in ULF magnetic components were acknowledged using the detected perturbations in ULF electric components (Ex, Ey and Ez in the geomagnetic coordinate system. Finally, the results reported in this paper were compared with previous results for this Samoa earthquake. Hence, the detected anomalies resulting from the magnetometer and ICE ULF waveforms in quiet geomagnetic conditions could be regarded as seismo-ionospheric precursors.

  11. NMR-Based Metabolomic Investigations on the Differential Responses in Adductor Muscles from Two Pedigrees of Manila Clam Ruditapes philippinarum to Cadmium and Zinc

    Directory of Open Access Journals (Sweden)

    Junbao Yu

    2011-09-01

    Full Text Available Manila clam Ruditapes philippinarum is one of the most important economic species in shellfishery in China due to its wide geographic distribution and high tolerance to environmental changes (e.g., salinity, temperature. In addition, Manila clam is a good biomonitor/bioindicator in “Mussel Watch Programs” and marine environmental toxicology. However, there are several pedigrees of R. philippinarum distributed in the marine environment in China. No attention has been paid to the biological differences between various pedigrees of Manila clams, which may introduce undesirable biological variation in toxicology studies. In this study, we applied NMR-based metabolomics to detect the biological differences in two main pedigrees (White and Zebra of R. philippinarum and their differential responses to heavy metal exposures (Cadmium and Zinc using adductor muscle as a target tissue to define one sensitive pedigree of R. philippinarum as biomonitor for heavy metals. Our results indicated that there were significant metabolic differences in adductor muscle tissues between White and Zebra clams, including higher levels of alanine, glutamine, hypotaurine, phosphocholine and homarine in White clam muscles and higher levels of branched chain amino acids (valine, leucine and isoleucine, succinate and 4-aminobutyrate in Zebra clam muscles, respectively. Differential metabolic responses to heavy metals between White and Zebra clams were also found. Overall, we concluded that White pedigree of clam could be a preferable bioindicator/biomonitor in marine toxicology studies and for marine heavy metals based on the relatively high sensitivity to heavy metals.

  12. NMR-based metabolomic investigations on the differential responses in adductor muscles from two pedigrees of Manila clam Ruditapes philippinarum to Cadmium and Zinc.

    Science.gov (United States)

    Wu, Huifeng; Liu, Xiaoli; Zhao, Jianmin; Yu, Junbao

    2011-01-01

    Manila clam Ruditapes philippinarum is one of the most important economic species in shellfishery in China due to its wide geographic distribution and high tolerance to environmental changes (e.g., salinity, temperature). In addition, Manila clam is a good biomonitor/bioindicator in "Mussel Watch Programs" and marine environmental toxicology. However, there are several pedigrees of R. philippinarum distributed in the marine environment in China. No attention has been paid to the biological differences between various pedigrees of Manila clams, which may introduce undesirable biological variation in toxicology studies. In this study, we applied NMR-based metabolomics to detect the biological differences in two main pedigrees (White and Zebra) of R. philippinarum and their differential responses to heavy metal exposures (Cadmium and Zinc) using adductor muscle as a target tissue to define one sensitive pedigree of R. philippinarum as biomonitor for heavy metals. Our results indicated that there were significant metabolic differences in adductor muscle tissues between White and Zebra clams, including higher levels of alanine, glutamine, hypotaurine, phosphocholine and homarine in White clam muscles and higher levels of branched chain amino acids (valine, leucine and isoleucine), succinate and 4-aminobutyrate in Zebra clam muscles, respectively. Differential metabolic responses to heavy metals between White and Zebra clams were also found. Overall, we concluded that White pedigree of clam could be a preferable bioindicator/biomonitor in marine toxicology studies and for marine heavy metals based on the relatively high sensitivity to heavy metals.

  13. Updated mitochondrial phylogeny of Pteriomorph and Heterodont Bivalvia, including deep-sea chemosymbiotic Bathymodiolus mussels, vesicomyid clams and the thyasirid clam Conchocele cf. bisecta.

    Science.gov (United States)

    Ozawa, Genki; Shimamura, Shigeru; Takaki, Yoshihiro; Yokobori, Shin-Ichi; Ohara, Yasuhiko; Takishita, Kiyotaka; Maruyama, Tadashi; Fujikura, Katsunori; Yoshida, Takao

    2017-02-01

    The mitochondrial genomes of bivalves have often been used for comparative genomics and for resolving phylogenetic relationships. More than 100 bivalve complete mitochondrial genomes have been sequenced to date. However, few mitochondrial genomes have been reported for deep-sea chemosymbiotic bivalves, which belong to the subclasses Pteriomorphia and Heterodonta. In the present study, we sequenced the mitochondrial genomes of eight deep-sea chemosymbiotic bivalve species: three species of Bathymodiolus mussels (B. japonicus, B. platifrons, and B. septemdierum), four species of vesicomyid clams (Abyssogena mariana, A. phaseoliformis, Isorropodon fossajaponicum, and Phreagena okutanii, all of which were formerly classified in the genus Calyptogena), and one species of thyasirid clam (Conchocele cf. bisecta). With a few exceptions, these mitochondrial genomes contained genes that are typical of metazoans: 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. The major non-coding region with a high A+T content of each genome, which contained tandem repeats and hairpins, was hypothesized to function as a control region. The phylogenetic trees of Pteriomorphia and Heterodonta were reconstructed based on the concatenated sequences of 14 shared genes. Bathymodiolus formed a monophyletic clade with asymbiotic Mytilidae mussels, the vesicomyid clams formed a monophyly that was sister to the Veneridae, and C. cf. bisecta branched basally in the Heterodonta. It is known that the gene orders of mitochondrial genomes vary among bivalves. To examine whether gene order variation exhibits phylogenetic signals, tree topologies based on the minimum number of gene rearrangements were reconstructed for two clades (superfamily Tellinoidea, which includes the Psammobiidae, Semelidae, Solecurtidae, and Tellinidae; and the clade comprising the Myidae, Mactridae, Arcticidae, Vesicomyidae, and Veneridae) with high statistical support in sequence-based phylogenies. The resulting tree

  14. Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B to quantify long-range transport of East Asian sulfur to Canada

    Directory of Open Access Journals (Sweden)

    A. van Donkelaar

    2008-06-01

    Full Text Available We interpret a suite of satellite, aircraft, and ground-based measurements over the North Pacific Ocean and western North America during April–May 2006 as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B campaign to understand the implications of long-range transport of East Asian emissions to North America. The Canadian component of INTEX-B included 33 vertical profiles from a Cessna 207 aircraft equipped with an aerosol mass spectrometer. Long-range transport of organic aerosols was insignificant, contrary to expectations. Measured sulfate plumes in the free troposphere over British Columbia exceeded 2 μg/m3. We update the global anthropogenic emission inventory in a chemical transport model (GEOS-Chem and use it to interpret the observations. Aerosol Optical Depth (AOD retrieved from two satellite instruments (MISR and MODIS for 2000–2006 are analyzed with GEOS-Chem to estimate an annual growth in Chinese sulfur emissions of 6.2% and 9.6%, respectively. Analysis of aircraft sulfate measurements from the NASA DC-8 over the central Pacific, the NSF C-130 over the east Pacific and the Cessna over British Columbia indicates most Asian sulfate over the ocean is in the lower free troposphere (800–600 hPa, with a decrease in pressure toward land due to orographic effects. We calculate that 56% of the measured sulfate between 500–900 hPa over British Columbia is due to East Asian sources. We find evidence of a 72–85% increase in the relative contribution of East Asian sulfate to the total burden in spring off the northwest coast of the United States since 1985. Campaign-average simulations indicate anthropogenic East Asian sulfur emissions increase mean springtime sulfate in Western Canada at the surface by 0.31 μg/m3 (~30% and account for 50% of the overall regional sulfate burden between 1 and 5 km. Mean measured daily surface sulfate concentrations taken in the Vancouver area increase by

  15. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  16. Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

    2008-01-31

    The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

  17. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Science.gov (United States)

    Zhao, Yanyun; Li, Chunjing; Huang, Bo; Liu, Shaojun; Huang, Qunying

    2014-12-01

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  18. Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-12-15

    Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

  19. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest

    Science.gov (United States)

    Neudorf, Christina M.; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B.

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes. PMID:28182645

  20. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae)

    Science.gov (United States)

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R.

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population. PMID:26745804

  1. Between a rock and a soft place: Using optical ages to date ancient clam gardens on the Pacific Northwest.

    Science.gov (United States)

    Neudorf, Christina M; Smith, Nicole; Lepofsky, Dana; Toniello, Ginevra; Lian, Olav B

    2017-01-01

    Rock-walled archaeological features are notoriously hard to date, largely because of the absence of suitable organic material for radiocarbon dating. This study demonstrates the efficacy of dating clam garden wall construction using optical dating, and uses optical ages to determine how sedimentation rates in the intertidal zone are affected by clam garden construction. Clam gardens are rock-walled, intertidal terraces that were constructed and maintained by coastal First Nation peoples to increase bivalve habitat and productivity. These features are evidence of ancient shellfish mariculture on the Pacific Northwest and, based on radiocarbon dating, date to at least the late Holocene. Optical dating exploits the luminescence signals of quartz or feldspar minerals to determine the last time the minerals were exposed to sunlight (i.e., their burial age), and thus does not require the presence of organic material. Optical ages were obtained from three clam garden sites on northern Quadra Island, British Columbia, and their reliability was assessed by comparing them to radiocarbon ages derived from shells underneath the clam garden walls, as well as below the terrace sediments. Our optical and radiocarbon ages suggest that construction of these clam garden walls commenced between ~1000 and ~1700 years ago, and our optical ages suggest that construction of the walls was likely incremental and increased sedimentation rates in the intertidal zone by up to fourfold. Results of this study show that when site characteristics are not amenable to radiocarbon dating, optical dating may be the only viable geochronometer. Furthermore, dating rock-walled marine management features and their geomorphic impact can lead to significant advances in our understanding of the intimate relationships that Indigenous peoples worldwide developed with their seascapes.

  2. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae.

    Directory of Open Access Journals (Sweden)

    Alexander Turra

    Full Text Available Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced or dead (closed valves were easily opened. Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population.

  3. Frequency, Magnitude, and Possible Causes of Stranding and Mass-Mortality Events of the Beach Clam Tivela mactroides (Bivalvia: Veneridae).

    Science.gov (United States)

    Turra, Alexander; Pombo, Maíra; Petracco, Marcelo; Siegle, Eduardo; Fonseca, Mariana; Denadai, Márcia R

    2016-01-01

    Stranding combined with mass-mortality events of sandy-beach organisms is a frequent but little-understood phenomenon, which is generally studied based on discrete episodes. The frequency, magnitude, and possible causes of stranding and mass-mortality events of the trigonal clam Tivela mactroides were assessed based on censuses of stranded individuals, every four days from September 2007 through December 2008, in Caraguatatuba Bay, southeastern Brazil. Stranded clams were classified as dying (closed valves did not open when forced) or dead (closed valves were easily opened). Information on wave parameters and the living intertidal clam population was used to assess possible causes of stranding. This fine-scale monitoring showed that stranding occurred widely along the shore and year-round, with peaks interspersed with periods of low or no mortality. Dead clams showed higher mean density than dying individuals, but a lower mean shell length, attributed to a higher tolerance to desiccation of larger individuals. Wave height had a significant negative relationship to the density of dying individuals, presumed to be due to the accretive nature of low-energy waves: when digging out, clams would be more prone to be carried upward and unable to return; while larger waves, breaking farther from the beach and with a stronger backwash, would prevent stranding in the uppermost areas. This ecological finding highlights the need for refined temporal studies on mortality events, in order to understand them more clearly. Last, the similar size structure of stranded clams and the living population indicated that the stranded individuals are from the intertidal or shallow subtidal zone, and reinforces the ecological and behavioral components of this process, which have important ecological and socioeconomic implications for the management of this population.

  4. Comparison of selenium bioaccumulation in the clams Corbicula fluminea and Potamocorbula amurensis: A bioenergetic modeling approach

    Science.gov (United States)

    Lee, B.-G.; Lee, J.-S.; Luoma, S.N.

    2006-01-01

    Selenium uptake from food (assimilation efficiency) and dissolved phase (influx rate) as well as loss kinetics (efflux rate) were compared between two bivalves, Corbicula fluminea and Potamocorbula amurensis. The effects of salinity and temperature on these kinetic parameters for both clam species also were evaluated. The Asiatic clam, C. fluminea, more efficiently assimilated Se associated with algae (66-87%) than Se associated with oxic sediments (20-37%). However, no consistent difference was found between Se assimilation efficiencies from both food types (19-60%) for P. amurensis. The temperature and salinity had a minor influence on the Se assimilation from ingested food. However, the effects of temperature and salinity were more evident in the uptake from dissolved sources. The influx rate of Se(IV) increased by threefold with the increase of temperature from 5 to 21??C for C. fluminea. The increase of salinity from 4 to 20 psu decreased the uptake rate constant (ku) of Se in P. amurensis from 0.011 to 0.005 L/g/h, whereas salinity change (0-8 psu) had a negligible effect on the Se influx rate of C. fluminea. The Se influx rate of P. amurensis decreased by half with the 3.5-fold increase in tissue dry weight. The rate constant of loss was greater for P. amurensis (0.029/d at 8 psu) than for C. fluminea (0.014/d at 0 psu and 0.01/d at 8 psu). A bioenergetic model suggests that dietary uptake is the dominant pathway for Se bioaccumulation in the two clams in San Francisco Bay and that interspecies differences in Se bioaccumulation can be explained by differences in food ingestion rates. ?? 2006 SETAC.

  5. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Franco, E-mail: baldi@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Gallo, Michele; Marchetto, Davide [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Faleri, Claudia [Department of Environmental Science ‘G. Sarfatti’, University of Siena, 53100 Siena (Italy); Maida, Isabel; Fani, Renato [Dipartimento di Biologia Evoluzionistica, Via Romana, 17, University of Florence, 50125 Florence (Italy)

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  6. Paralytic shellfish poisoning toxins accumulation in purple clam Hiatula rostrata and toxic effect on milkfish Chanos chanos larval fish.

    Science.gov (United States)

    Chen, C Y

    2001-11-01

    In an attempt to feed purple clams (Hiatula rostrata) with dinoglagellate Alexandrium minutum, the maximal accumulation toxicity of paralytic shellfish poisoning (PSP) toxins reached 40.6 MU/g on day 5 of feeding. Subsequently, the toxicity increased no further, although purple clams ingested more toxic algae. Furthermore, when milkfish (Chanos chanos) larvae were treated with toxic, nontoxic A. minutum or PSP toxin-containing extract in the water medium, it was found that the mortality of fish increased with the increasing concentrations of toxic algae. PSP toxin-containing extract did not show any toxic effect on milkfish larvae.

  7. Environmental salinity modulates the effects of elevated CO2 levels on juvenile hard-shell clams, Mercenaria mercenaria.

    Science.gov (United States)

    Dickinson, Gary H; Matoo, Omera B; Tourek, Robert T; Sokolova, Inna M; Beniash, Elia

    2013-07-15

    Ocean acidification due to increasing atmospheric CO2 concentrations results in a decrease in seawater pH and shifts in the carbonate chemistry that can negatively affect marine organisms. Marine bivalves such as the hard-shell clam, Mercenaria mercenaria, serve as ecosystem engineers in estuaries and coastal zones of the western Atlantic and, as for many marine calcifiers, are sensitive to the impacts of ocean acidification. In estuaries, the effects of ocean acidification can be exacerbated by low buffering capacity of brackish waters, acidic inputs from freshwaters and land, and/or the negative effects of salinity on the physiology of organisms. We determined the interactive effects of 21 weeks of exposure to different levels of CO2 (~395, 800 and 1500 μatm corresponding to pH of 8.2, 8.1 and 7.7, respectively) and salinity (32 versus 16) on biomineralization, shell properties and energy metabolism of juvenile hard-shell clams. Low salinity had profound effects on survival, energy metabolism and biomineralization of hard-shell clams and modulated their responses to elevated PCO2. Negative effects of low salinity in juvenile clams were mostly due to the strongly elevated basal energy demand, indicating energy deficiency, that led to reduced growth, elevated mortality and impaired shell maintenance (evidenced by the extensive damage to the periostracum). The effects of elevated PCO2 on physiology and biomineralization of hard-shell clams were more complex. Elevated PCO2 (~800-1500 μatm) had no significant effects on standard metabolic rates (indicative of the basal energy demand), but affected growth and shell mechanical properties in juvenile clams. Moderate hypercapnia (~800 μatm PCO2) increased shell and tissue growth and reduced mortality of juvenile clams in high salinity exposures; however, these effects were abolished under the low salinity conditions or at high PCO2 (~1500 μatm). Mechanical properties of the shell (measured as microhardness and

  8. Evaluation of Norfolk Harbor Deepening Project (A Study on Its Possible Impact on Oysters, Hard Clams and Oyster Drills).

    Science.gov (United States)

    1984-06-20

    Virginia 23062 DTIC 20 June 1984 ELECTE ~L&JMAR 12 i9BB IA B! ,", Contract No. DACW65-84-M-0056 -Ap’oved to: publicO t01b0 I D)WtbuZidon Unlimited .~Norfolk...impact on the transport of the larval oysters and hard clams during their planktonic stage. Oysters and hard clams are widely tolerant to high salinity...planktonic for about 2 weeks and during this period are transported by currents. This latter aspect will be covered later in our discussion on oysters. ~i

  9. Expression of cyp1a protein in the freshwater clam Corbicula fluminea (Müller

    Directory of Open Access Journals (Sweden)

    Vranković Jelena

    2011-01-01

    Full Text Available We investigated the expression of CYP1A in the foot, gill and visceral mass of the freshwater clam Corbicula fluminea in relation to polychlorinated biphenyls (PCBs exposure. Different PCBs congeners were found in the foot and visceral mass, while the expression of CYP1A was observed only in the visceral mass. However the level of CYP1A expression in the visceral mass was not related to the level of PCBs present in the tissue. Our results indicate a higher rate of biotransformation and lower threshold of CYP1A induction in the visceral mass compared with other tissues.

  10. Constraints on Anthropogenic NOx Emissions from Geostationary Satellite Observations in a Regional Chemical Data Assimilation System: Evaluation Using Observing System Simulation Experiments

    Science.gov (United States)

    Liu, X.; Mizzi, A. P.; Anderson, J. L.; Fung, I. Y.; Cohen, R. C.

    2015-12-01

    Nitrogen oxides (NOx=NO+NO2) control the tropospheric ozone (O3) budget, the abundance of the hydroxyl radical (OH), the formation of organic and inorganic nitrate aerosol, and therefore affect air quality and climate. There remain significant uncertainties in the processes responsible for NOx emissions and subsequent mixing and chemical removal. NOx has a short lifetime and its emissions show high spatiotemporal variability at urban scale. Future geostationary satellite instruments including TEMPO, GEMS and Sentinel-4 will provide hourly time resolution and high spatial resolution observations providing maps of NO2 on diurnal and local scales. Here we determine the extent to which a TEMPO like instrument can quantify urban-scale NOx emissions using a regional data assimilation (DA) system comprising of a chemical transport model, WRF-Chem, a TEMPO simulator and the DART Ensemble Adjustment Kalman Filter. We generate synthetic TEMPO observations by sampling from a nature run on an urban scale domain. We consider the effect of albedo, surface pressure, solar and viewing angles and a priori NO2 profiles on the TEMPO NO2 averaging kernel to achieve scene-dependent instrument sensitivity. We estimate NOx emissions using DART in a state augmentation approach by including NOx emissions in the state vector being analyzed. The ensemble-based statistical estimation of error correlations between concentrations and emissions are critical as they determine the impact of assimilated observations. We describe observing system simulation experiments to explore the optimal approach in the ensemble-based DA system to estimate hourly-resolved NOx emissions from TEMPO NO2 observations. Several case studies will be presented examining the role of covariance localization length and chemical perturbations on the success of the approach.

  11. 27-day solar forcing of mesospheric temperature, water vapor and polar mesospheric clouds from the AIM SOFIE and CIPS satellite experiments

    Science.gov (United States)

    Thomas, Gary; Thurairajah, Brentha; von Savigny, Christian; Hervig, Mark; Snow, Martin

    2016-04-01

    Solar cycle variations of ultraviolet radiation have been implicated in the 11-year and 27-day variations of Polar Mesospheric Cloud (PMC) properties. Both of these variations have been attributed to variable solar ultraviolet heating and photolysis, but no definitive studies of the mechanisms are available. The solar forcing issue is critical toward answering the broader question of whether PMC's have undergone long-term changes, and if so, what is the nature of the responsible long-term climate forcings? One of the principal goals of the Aeronomy of Ice in the Mesosphere satellite mission was to answer the question: "How does changing solar irradiance affect PMCs and the environment in which they form?" We describe an eight-year data set from the AIM Solar Occultation for Ice Experiment (SOFIE) and the AIM Cloud Imaging and Particle Size (CIPS) experiment. Together, these instruments provide high-precision measurements of high-latitude summertime temperature (T), water vapor (H2O), and PMC ice properties for the period 2007-present. The complete temporal coverage of the summertime polar cap region for both the primary atmospheric forcings of PMC (T and H2O), together with a continually updated time series of Lyman-alpha solar irradiance, allows an in-depth study of the causes and effects of 27-day PMC variability. The small responses of these variables, relative to larger day-to-day changes from gravity waves, tides, inter-hemispheric coupling, etc. require a careful statistical analysis to isolate the solar influence. We present results for the 27-day responses of T, H2O and PMC for a total of 15 PMC seasons, (30 days before summer solstice to 60 days afterward, for both hemispheres). We find that the amplitudes and phase relationships are not consistent with the expected mechanisms of solar UV heating and photolysis - instead we postulate a primarily dynamical response, in which a periodic vertical wind heats/cools the upper mesosphere, and modulates PMC

  12. Tethered satellite design

    Science.gov (United States)

    Manarini, G.

    1986-01-01

    The capability of the satellite to perform a variety of space operations to be accomplished from the shuttle is reviewed considering use of the satellite with man-in-loop and closed loop modes and deployment (toward or away from Earth, up to 100 km), stationkeeping, retrieval and control of the satellite. Scientific payloads are to be used to perform experiments and scientific investigation for applications such as magnetometry, electrodynamics, atmospheric science, chemical release, communications, plasmaphysics, dynamic environment, and power and thrust generation. The TSS-S will be reused for at least 3 missions after reconfiguration and refurbishment by changing the peculiar mission items such as thermal control, fixed boom for experiments, aerodynamic tail for yaw attitude control, external skin, experiments, and any other feature. The TSS-S is to be composed of three modules in order to allow independent integration of a single module and to facilitate the refurbishment and reconfiguration between flights. The three modules are service, auxiliary propulsion, and payload modules.

  13. Studies on molluscan glycosaminoglycans (GAG) from backwater clam Donax cuneatus (Linnaeus)

    Institute of Scientific and Technical Information of China (English)

    P Vijayabaskar; ST Somasundaram

    2012-01-01

    Objective: To investigate the potent and specific anticoagulant activity of molluscan glycosaminoglycans (GAGs) isolated from whole clam tissue Donax cuneatus (D. cuneatus). Methods: Purification of few milligram quantities of GAGs from this tissue sample permitted a thorough examination of its anticoagulant activity characterization, which was partially purified by fractionation by anion exchange chromatography using DEAE cellulose column. The isolated crude and partially purified fractionated sample was showing metachromatic shift while using azure-A. The sample also exhibited prominent of biological and anti-fXa anticoagulant activity assays. Mobility was analyzed by two different buffer systems using agarose gel electrophoresis.Results:The fractionated molluscan GAG was also found to have similar peaks as that of standard heparin when assessed by the FT-IR spectrum. Finally molecular weight was determined by the gradient PAGE for crude and fractionated-II GAG, which were found to be 65 000 Da and 50 000 Da, respectively. Conclusions: The bivalve GAG was subjected to fractionation for further purification and its chemical components were analyzed. The fractionated clam heparin also showed substantial in vitro anticoagulant activity than that of commercial heparins.

  14. Two new miniature inverted-repeat transposable elements in the genome of the clam Donax trunculus.

    Science.gov (United States)

    Šatović, Eva; Plohl, Miroslav

    2017-06-26

    Repetitive sequences are important components of eukaryotic genomes that drive their evolution. Among them are different types of mobile elements that share the ability to spread throughout the genome and form interspersed repeats. To broaden the generally scarce knowledge on bivalves at the genome level, in the clam Donax trunculus we described two new non-autonomous DNA transposons, miniature inverted-repeat transposable elements (MITEs), named DTC M1 and DTC M2. Like other MITEs, they are characterized by their small size, their A + T richness, and the presence of terminal inverted repeats (TIRs). DTC M1 and DTC M2 are 261 and 286 bp long, respectively, and in addition to TIRs, both of them contain a long imperfect palindrome sequence in their central parts. These elements are present in complete and truncated versions within the genome of the clam D. trunculus. The two new MITEs share only structural similarity, but lack any nucleotide sequence similarity to each other. In a search for related elements in databases, blast search revealed within the Crassostrea gigas genome a larger element sharing sequence similarity only to DTC M1 in its TIR sequences. The lack of sequence similarity with any previously published mobile elements indicates that DTC M1 and DTC M2 elements may be unique to D. trunculus.

  15. Population dynamics of the freshwater clam Galatea paradoxa from the Volta River, Ghana

    Directory of Open Access Journals (Sweden)

    Adjei-Boateng D.

    2012-07-01

    Full Text Available Population parameters such as asymptotic (L∞, growth coefficient (K, mortality rates (Z,F and M, exploitation level (E and recruitment pattern of the freshwater clam Galatea paradoxa were estimated using length-frequency data from the Volta River estuary, Ghana. The L∞ for G. paradoxa at the Volta estuary was 105.7 mm, the growth coefficient (K and the growth performance index (Ǿ ranged between 0.14–0.18 year-1 and 3.108–3.192, respectively. Total mortality (Z was 0.65–0.82 year-1, while natural mortality (M and fishing mortality (F were 0.35–0.44 year-1 and 0.21–0.47 year-1, respectively, with an exploitation level of 0.32–0.57. The recruitment pattern suggested that G. paradoxa has year-round recruitment with a single pulse over an extended period (October–March in the Volta River. The Volta River stock of G. paradoxa is overfished and requires immediate action to conserve it. This can be achieved by implementing a minimum landing size restriction and intensifying the culture of smaller clams which is a traditional activity at the estuary.

  16. Fishery of the short-necked clam Paphia undulata in Southern Negros Occidental, Central Philippines

    Directory of Open Access Journals (Sweden)

    Karen A. Villarta

    2010-06-01

    Full Text Available This study documents the fishery of the short-necked clam Paphia undulata in coastal waters of southern Negros Occidental. Catch and effort estimates were determined based on daily records of compressor divers gathered between February-July 2008 in Himamaylan City and July 2008-May 2009 in the town of Hinigaran. Fishing and marketing practices in both areas were also documented and population biology information noted.Compared to earlier conditions, present fishing patterns show a worsened stage of overexploitation primarily characterized by collection of predominantly small and immature (mostly <45 mm shell lengths sizes. Intensity/duration and location of fishing also varied due to both abundance and demand factors.The difference in sizes of clams and the varying fishing durations in each area suggest a non-uniform pattern of settlement resulting most likely from differential larval recruitment, the likely factors causing the local boom and bust fishery. The larger and long term extent of the effect of these factors can only be further investigated by parallel 2-3 year fishery-dependent and -independent surveys

  17. Molecular Phylogeny of Giant Clams Based on Mitochondrial DNA Cytochrome C Oxidase I Gene

    Directory of Open Access Journals (Sweden)

    AGUS NURYANTO

    2007-12-01

    Full Text Available There is an uncertainty for the relationships among giant clam species of Tridacninae, in particular among species belongs to subgenus Chametrachea i.e. Tridacna crocea, T. maxima, and T. squamosa based on different genetic markers. This study examined the relationships among three species within subgenus Chametrachea compared to the previous studies. Neighbour Joining, Maximum Parsimony and Maximum Likelihood tree were constructed based on 455 bp of the mitochondrial DNA cytochrome c oxidase I gene from T. crocea, T. squamosa, T. maxima, T. gigas, and several sequences derived from Genbank for the outgroups. The results showed that giant clams formed a monophyletic group. Within Tridacna group, T. crocea was more closely related to T. squamosa than to T. maxima and they formed a monophyletic group. T. crocea and T. squamosa were sister taxa and sister group to T. maxima and T. gigas. Close affinity between T. crocea and T. squamosa was also supported by high similarity on nucleotide level (94.30% and concordant with the results of the previous studies using mitochondrial 16S rRNA and nuclear 18S rRNA.

  18. A light-dependent ammonia-assimilating mechanism in the ctenidia of a giant clam

    Science.gov (United States)

    Hiong, Kum C.; Choo, Celine Y. L.; Boo, Mel V.; Ching, Biyun; Wong, Wai P.; Chew, Shit F.; Ip, Yuen K.

    2017-03-01

    Giant clams harbor symbiotic zooxanthellae and manifest light-enhanced calcification. In light, they also increase the absorption and assimilation of exogenous ammonia, but the roles of the host and symbionts are unclear and the reason for light dependency remains enigmatic. Here, we report the complete coding cDNA sequence of a glutamine synthetase (GS), from the ctenidia (gill) of Tridacna squamosa. The deduced GS amino acid sequence was closely related to other animal GSs, indicating a host origin. The GS/GS transcript level and protein abundance increased significantly in the ctenidia after 12 h of light exposure. These results denote the ctenidia as the site of light-enhanced ammonia absorption with the absorbed ammonia being assimilated to glutamine by the host GS. Immunofluorescence microscopy confirmed that GS was expressed predominantly in the cytoplasm of the epithelial cells separating the tertiary water channels from the hemolymph inside the ctenidia. Hence, unlike symbiotic cnidarians, the host clam probably supplies exogenous nitrogen as glutamine from the ctenidia, through the hemolymph and tubular fluid, to the nitrogen-deficient zooxanthellae which reside extracellularly in the extensible outer mantle. This is the first report on light-dependent gene and protein expression of a host enzyme involved in nitrogen metabolism in an alga-invertebrate association.

  19. Genetic diversity of giant clams (Tridacna spp.) and their associated Symbiodinium in the central Red Sea

    KAUST Repository

    Pappas, Melissa K.

    2017-05-19

    The biodiversity of the Red Sea remains relatively understudied, particularly for invertebrate taxa. Documenting present patterns of biodiversity is essential for better understanding Red Sea reef ecosystems and how these ecosystems may be impacted by stressors (such as fishing and climate change). Several species of giant clams (genus Tridacna) are reported from the Red Sea, although the majority of research effort has occurred in the Gulf of Aqaba. We investigated the genetic diversity (16S rDNA) of the Tridacna species found in the central Saudi Arabian Red Sea. We also investigated the genetic diversity (ITS rDNA) of symbiotic dinoflagellates Symbiodinium associated with these clams. Samples were collected from nine reefs on a cross-shelf gradient near Thuwal, Saudi Arabia. Two species, T. squamosa and T. maxima, were recorded, with the latter being the most abundant. Tridacna squamosina, a species recently reported in the northern Red Sea, was not found, suggesting that this species is not present or is very rare in our study region. All tridacnids sampled were found to harbor Symbiodinium grouped in Clade A, considered an opportunistic, heat-tolerant symbiont group in anemones and corals. The consistent association with Clade A Symbiodinium in central Red Sea tridacnids may reflect the consequence of adaptation to the relatively extreme conditions of the Red Sea. This study contributes to an ever-growing catalog of Red Sea biodiversity and serves as important baseline information for a region experiencing dynamic pressures.

  20. Overview on the welding technologies of CLAM steel and the DFLL TBM fabrication

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    2016-12-01

    Full Text Available Dual Functional Lithium Lead (DFLL blanket was proposed for its advantages of high energy exchange efficiency and on-line tritium extraction, and it was selected as the candidate test blanket module (TBM for China Fusion Engineering Test Reactor (CFETR and the blanket for Fusion Design Study (FDS series fusion reactors. Considering the influence of high energy fusion neutron irradiation and high heat flux thermal load on the blanket, China Low Activation Martensitic (CLAM steel was selected as the structural material for DFLL blanket. The structure of the blanket and the cooling internal components were pretty complicated. Meanwhile, high precision and reliability were required in the blanket fabrication. Therefore, several welding techniques, such as hot isostatic pressing diffusion bonding, tungsten inner gas welding, electron beam welding and laser beam welding were developed for the fabrication of cooling internals and the assembly of the blanket. In this work, the weldability on CLAM steel by different welding methods and the properties of as-welded and post-weld heat-treated joints were investigated. Meanwhile, the welding schemes and the assembly strategy for TBM fabrication were raised. Many tests and research efforts on scheme feasibility, process standardization, component qualification and blanket assembly were reviewed.

  1. Selective pressurized liquid extraction technique capable of analyzing dioxins, furans, and PCBs in clams and crab tissue.

    Science.gov (United States)

    Subedi, Bikram; Aguilar, Lissette; Williams, E Spencer; Brooks, Bryan W; Usenko, Sascha

    2014-04-01

    A selective pressurized liquid extraction technique (SPLE) was developed for the analysis of polychlorodibenzo-p-dioxins, polychlorodibenzofurans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) in clam and crab tissue. The SPLE incorporated multiple cleanup adsorbents (alumina, florisil, silica gel, celite, and carbopack) within the extraction cell. Tissue extracts were analyzed by high resolution gas chromatography coupled with electron capture negative ionization mass spectrometry. Mean recovery (n = 3) and percent relative standard deviation for PCDD/Fs and dl-PCBs in clam and crabs was 89 ± 2.3 and 85 ± 4.0, respectively. The SPLE method was applied to clams and crabs collected from the San Jacinto River Waste Pits, a Superfund site in Houston, TX. The dl-PCBs concentrations in clams and crabs ranged from 50 to 2,450 and 5 to 800 ng/g ww, respectively. Sample preparation time and solvents were reduced by 92 % and 65 %, respectively, as compared to USEPA method 1613.

  2. Caffeine impacts in the clam Ruditapes philippinarum: Alterations on energy reserves, metabolic activity and oxidative stress biomarkers.

    Science.gov (United States)

    Cruz, Diogo; Almeida, Ângela; Calisto, Vânia; Esteves, Valdemar I; Schneider, Rudolf J; Wrona, Frederick J; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2016-10-01

    Caffeine is known to be one of the most consumed psychoactive drugs. For this reason, caffeine is continuously released into the environment with potential impacts on inhabiting organisms. The current study evaluated the biochemical alterations induced in the clam species Ruditapes philippinarum after exposure for 28 days to caffeine (0.5, 3.0 and 18.0 μg/L). The results obtained showed that, with the increasing caffeine concentrations, an increase in clams defense mechanisms (such as antioxidant and biotransformation enzymes activity) was induced which was accompanied by an increase in protein content. Nevertheless, although an increase on defense mechanisms was observed, clams were not able to prevent cells from lipid peroxidation that increased with the increase of caffeine concentration. Furthermore, with the increase of exposure concentrations, clams increased their metabolic activity (measured by electron transport activity), reducing their energy reserves (glycogen content), to fight against oxidative stress. Overall, the present study demonstrated that caffeine may impact bivalves, even at environmentally relevant concentrations, inducing oxidative stress in organisms. The present study is an important contribution to address knowledge gaps regarding the impacts of long-term exposures to pharmaceuticals since most of the studies assessed the effects after acute exposures, most of them up to 96 h.

  3. Sodium Gill Potential as a Tool to Monitor Valve Closure Behavior in Freshwater Clam Corbicula fluminea in Response to Copper

    Directory of Open Access Journals (Sweden)

    Wei-Yu Chen

    2008-09-01

    Full Text Available Valve closure behavior in freshwater clam Corbicula fluminea is a biologically sensitive endpoint. The purpose of this paper was to derive an electrophysiological response model of C. fluminea to assess copper (Cu-sodium (Na interactions in gill membrane, whereby valve closure behavior and Cu toxicity could be monitored. The proposed model was based on the integration of Cu bioavailability, Na and Cu internalizations, and electrochemically-based gill potentials. Based on Na active transport under non-equilibrium conditions, predicted gill potential of -8.2 mV agreed reasonably well with published the measured transepithelial potential of -7 mV in C. fluminea. Our proposed framework captured the general features observed in model applications including: (i 50% inhibitory Cu2+ activities for Na membrane potential (ENa and uptake rate (JNa were estimated to be 0.072 and 0.043 mM, respectively, with a stoichiometry of 3Cu2+: 1ENa and 1JNa; (ii the external Cu2+-dependent internal Na concentration could be parsimoniously estimated, and (iii the site-specific clam gill potentials could be monitored. Here we provided a new approach to monitor waterborne metal toxicity to reduce the nationwide economic losses due to bans on harvesting of contaminated clam and the potential risks to the health of clams.

  4. The involvement of cysteine-rich intestinal protein in early development and innate immunity of Asiatic hard clam, Meretrix meretrix.

    Science.gov (United States)

    Chen, Hongjian; Yang, Xue; Tang, Ting; Li, Juan; Liu, Baozhong; Liu, Fengsong; Xie, Song

    2014-10-01

    Cysteine-rich intestinal protein (CRIP), a Zn(2+)-binding protein, contains a single copy of the highly conserved double-zinc-finger structure known as the LIM (lin-11-isl-1-mec-3) motif. In this paper, a cDNA encoding MmCRIP was isolated from the Asiatic hard clam Meretrix meretrix. The full-length cDNA of MmCRIP consists of a 237-bp open reading frame that encodes a polypeptide of 78 amino acids with a predicted molecular weight (MW) of 8635.8 Da and theoretical isoelectric point (pI) of 9.01. Bioinformatics analysis showed that it belonged to a new member of the CRIP subfamily. Relationship analysis revealed that MmCRIP has high-levels of sequence similarity to many CRIPs reported in other animals, particularly in invertebrates. Real-time PCR analysis showed that the highest level of MmCRIP expression was in hemocyte tissue and at pediveligers stage. To investigate immune function, mature clams were challenged with Aeromonas hydrophila. During A. hydrophila infection, up-regulation of MmCRIP transcript in clam's hemocyte, gill and hepatopancreas was detected. DsRNAi (double-strand RNA interference) approach was employed to study the function of MmCRIP and the data showed that inactivation of the MmCRIP gene blocked larvae development and caused mass mortalities. The probable roles of MmCRIP in clam early development and innate immunity are presented for the first time.

  5. Intra-specific diet shift in manila clams (Ruditapes philippinarum) as revealed by carbon and nitrogen stable isotopes and fatty acid biomarker

    Science.gov (United States)

    Suh, Y.; Shin, K.

    2011-12-01

    Manila clams sampled in Seonjae Island, Korea with shell lengths (SL) below 19.76 mm in average showed a significantly depleted carbon and nitrogen isotope values (Pcultured in IFHRI. The result of fatty acid composition of manila clams in relation to size or growth rate suggests that fast growing clams would have rapid metabolism of fatty acids not required by the animals and an accumulation of the essential fatty acids (PUFA). In addition, their higher energy requirement and more active state of development would further diminish lipid reserve of the species.

  6. HETE Satellite Power Subsystem

    OpenAIRE

    1993-01-01

    The HETE (High-Energy Transient Experiment) satellite a joint project between MIT's Center for Space Research and AeroAstro. is a high-energy gamma-ray burst/X-Ray/UV observatory platform. HETE will be launched into a 550 km circular orbit with an inclination of 37.7°, and has a design lifetime of 18 months. This paper presents a description of the spacecraft's power subsystem, which collects, regulates, and distributes power to the experiment payload modules and to the various spacecraft sub...

  7. The effects of clam fishing on the properties of surface sediments in the lagoon of Venice, Italy

    Directory of Open Access Journals (Sweden)

    R. J. Aspen

    2004-01-01

    Full Text Available Harvesting of clams(Tapes philippinarum has important socio-economic and environmental implications for the Venice lagoon area, Italy. Clam harvesting disrupts the structure of benthic communities but the effects upon sediment stability and surface structure remain unclear. The effect of clam fishing on the sediment properties of the lagoon bed was investigated at two different sites, a heavily fished site (San Angelo and an infrequently fished site (San Giaccomo. Both sites were assessed for immediate impacts of fishing, using indicators of biogenic sediment stabilisation. Samples were taken at three points along three 100 m linear transects at each site prior to and post fishing. Paired samples were also taken parallel to each transect at a distance of 5m, to allow for temporal variation. Sediment stability, measured with a cohesive strength meter (CSM, was significantly higher at the less impacted site (F1,34 = 6.23, p a (chl a, colloidal-S carbohydrate and dry bulk density were observed on the transect after fishing but not adjacent to the fishing path. At the heavily impacted site, clam fishing by trawling had, in general, no significant effect on the biological and physical properties (although chl a did decrease significantly after fishing. The lack of a significant impact from fishing at the impacted site was attributed to the higher frequency of fishing occurring in this area. Hence, frequent fishing of the lagoon prevents establishment of biotic communities, preventing biostabilisation and thus reduces the stability of the surface sediment. Keywords: clam harvesting, erosion threshold, microphytobenthos, sediment, stability

  8. Quantitative determination of gymnodimine-A by high performance liquid chromatography in contaminated clams from Tunisia coastline.

    Science.gov (United States)

    Marrouchi, Riadh; Dziri, Faten; Belayouni, Nawel; Hamza, Asma; Benoit, Evelyne; Molgó, Jordi; Kharrat, Riadh

    2010-10-01

    Quantitative determination by high performance liquid chromatography (HPLC) was performed for gymnodimine-A (GYM-A), a phycotoxin responsible for the contamination of Tunisian clams. This study demonstrates a rapid and reproducible HPLC-ultraviolet (UV) method for extraction, detection and quantification of GYM-A in toxic clams. The extraction of GYM-A from the digestive gland of clams in acetone, subsequent clean-up with diethyl ether and extraction with dichloromethane is the more valid protocol. Chromatography analyses were performed using a gradient of acetonitrile-water (10:90 to 90:10), containing trifluoroacetic acid (0.1%) for 20 min at 1 mL/min rate with a C18 column. Recovery rates exceeded 96%, and limits of detection and quantification were 5 ng/mL and 8 ng/g digestive gland, respectively. Repeatability and reproducibility were tested for various samples containing different levels of GYM-A. A significant correlation was observed between toxicity level of samples and the determined amount of GYM-A. Also, the persistence of GYM-A in contaminated clams from Boughrara lagoon was demonstrated. The kinetics discharge study of GYM-A in controlled medium, during 1 month, showed that the process of depuration was biphasic with an exponential discharge of 75% of the total amount of sequestered GYM-A during the first 12 days followed by a slow discharge (>10%) for the subsequent days up to the seventeenth day. This is the first time that a quantitative study of GYM-A in clams from Tunisian coasts is performed through the development of a new method for detection and quantify of this phycotoxin. We found HPLC-UV a reliable and suitable alternative to the mouse bioassay.

  9. Substantial changes in hemocyte parameters of Manila clam Ruditapes philippinarum two years after the Hebei Spirit oil spill off the west coast of Korea.

    Science.gov (United States)

    Hong, Hyun-Ki; Donaghy, Ludovic; Kang, Chang-Keun; Kang, Hyun-Sil; Lee, Hee-Jung; Park, Heung-Sik; Choi, Kwang-Sik

    2016-07-15

    Two years after the Hebei Spirit oil spill occurred off the west coast of Korea, we determined sub-lethal effects of the spilled oil on hemocyte parameters of Ruditapes philippinarum in the damaged areas. Clams in the spilled sites displayed unusually high proportion of granulocytes, which may result in higher phagocytosis capacity and reactive oxygen species production. Hemocytes in clams from the polluted sites also displayed less DNA damage and mortality than in the control site, possibly due to a faster phagocytosis of the impaired cells. Glycogen, the major energetic reserve, was depleted in clams from the spilled sites, potentially due to energetic consumption for maintenance of a large pool of granulocytes, detoxification processes and oxidative stress. Modified hemocyte parameters in clams in the spilled area, may reflect sub-lethal physiological stresses caused by the residual oils in the sediment, in conjunction with environmental modifications such as food availability and pathogens pattern.

  10. Spatio-temporal variations in biochemical composition, condition index and percentage edibility of the clam, Paphia malabarica (Chemnitz) from estuarine regions of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nagvenkar, S.S.; Jagtap, T.G.

    Biochemical compositions, condition index (CI) and percentage edibility (PE) of an estuarine clam, Paphia malabarica, were studied from two estuarine regions of Goa during March 2009 to March 2010. Relationships between nutritive components...

  11. Bio-accumulation of copper, zinc, iron and manganese in oyster Saccostrea cucullata, Snail Cerithium rubus and Clam Tellina angulata from the Bombay coast

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Nair, V.R.; Moraes, C.

    Metal content was determined in three groups of molluscs - an oyster Saccostrea cucullata, snail Cerithium rubus and clam Tellina angulata from three sites along the Bombay Coast. Seasonal difference in copper content was significant in S. cucullata...

  12. Effect of acclimatization on hemocyte functional characteristics of the Pacific oyster (Crassostrea gigas) and carpet shell clam (Ruditapes decussatus).

    Science.gov (United States)

    Hurtado, Miguel Ángel; da Silva, Patricia Mirella; Le Goïc, Nelly; Palacios, Elena; Soudant, Philippe

    2011-12-01

    Most experimental procedures on molluscs are done after acclimatization of wild animals to lab conditions. Similarly, short-term acclimation is often unavoidable in a field survey when biological analysis cannot be done within the day of sample collection. However, acclimatization can affect the general physiological condition and particularly the immune cell responses of molluscs. Our aim was to study the changes in the hemocyte characteristics of the Pacific oyster Crassostrea gigas and the carpet shell clam Ruditapes decussatus acclimated 1 or 2 days under emersed conditions at 14 ± 1 °C and for 1, 2, 7, or 10 days to flowing seawater conditions (submerged) at 9 ± 1 °C, when compared to hemolymph withdrawn from organisms sampled in the field and immediately analyzed in the laboratory (unacclimated). The hemocyte characteristics assessed by flow cytometry were the total (THC) and differential hemocyte count, percentage of dead cells, phagocytosis, and reactive oxygen species (ROS) production. Dead hemocytes were lower in oysters acclimated both in emersed and submerged conditions (1%-5%) compared to those sampled in the field (7%). Compared to oysters, the percentage of dead hemocytes was lower in clams (0.4% vs. 1.1%) and showed a tendency to decrease during acclimatization in both emersed and submerged conditions. In comparison to organisms not acclimated, the phagocytosis of hemocytes decreased in both oysters and clams acclimated under submerged conditions, but was similar in those acclimated in emersed conditions. The ROS production remained stable in both oysters and clams acclimated in emersed conditions, whereas in submerged conditions ROS production did not change in both the hyalinocytes and granulocytes of oysters, but increased in clams. In oysters, the THC decreased when they were acclimated 1 and 2 days in submerged conditions and was mainly caused by a decrease in granulocytes, but the decrease in THC in oysters acclimated 2 days in emersed

  13. Use of antioxidant enzymes of clam Ruditapes philippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Zhu, Lin; Tang, Xuexi; Wang, Ying; Sui, Yadong; Xiao, Hui

    2016-03-01

    The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

  14. Parasites of the hard clam Meretrix meretrix Linnaeus from Western Johor Straits, Malaysian

    Science.gov (United States)

    Azmi, Nur Fauzana; Ghaffar, Mazlan Abd.; Cob, Zaidi Che

    2014-09-01

    This study describes the apicomplexa as well as other parasites infecting organs/tissues of the hard clam Meretrix meretrix Linnaeus, from Merambong Shoal, Western Johor Straits, Malaysia. Samples were collected randomly by hand picking, in November and December 2013. Histological techniques were performed, stained using Masson's Trichrome protocol and observed under light microscope. The results showed that gonad and gill were the most infected organs followed by digestive gland, intestine and adductor muscle. No pathology condition was observed in the mantle. Histophatological examination showed that the gregarine, Nematopsis, unidentified coccidian and Perkinsus were found in the gill and gonad, and also in the numerous hemocytes. Other pathological conditions such as bacteria-like inclusion and intracellular bacteria were also observed in the same organs. Further investigations are needed particularly on other molluscs present at the study area. Understanding the morphology and pathology of parasites infecting mollusks are very important for management of the resources.

  15. Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Scanlon, Sine Hedegaard; Jensen, L.B.

    2005-01-01

    Until recently, little focus was given to the presence of diarrhetic shellfish poisoning ( DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed....... Samples of Danish surf clams ( Spisola spp.) and blue mussels ( Mytilus edulis) from 1999 - 2004 were analysed by liquid chromatography coupled with tandem mass spectrometry ( LC/ MS/ MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level...... of okadaic acid esters of the total okadaic acid equivalents ranged from 21 to 86%, mean 59%. The probability of a high percentage of okadaic acid esters seems to increase with higher amounts of total okadaic acid equivalents in the bivalves. The large prevalence of DSP toxin esters are of particular...

  16. Comparative Study of the Accumulation of Ni in Different Tissues of Mussels and Soft Clams

    Directory of Open Access Journals (Sweden)

    Chalkiadakis O.

    2013-04-01

    Full Text Available Two bivalves, the mussel Mytilus galloprovincialis, and the soft clam Callista chione were exposed to various Ni concentrations for a total period of 20 days, and then a depuration period of 10 days followed. Nickel accumulation in gills, mantle and the remaining body of the animals was measured after 5, 10, 15 and 20 days of exposure to Ni-contaminated seawater. The two organisms showed different behavior regarding Ni accumulation in all three tissues examined. In all concentrations, Ni accumulation increased with time in all three tissues of Mytilus galloprovincialis with gills being the most effective accumulator per dry mass. On the other hand, Callista chione showed an initial response to Ni contamination the first 5 days, followed by stabilization or even a slight decrease of Ni accumulation.

  17. Combined proteomic and metallomic analyses in Scrobicularia plana clams to assess environmental pollution of estuarine ecosystems.

    Science.gov (United States)

    González-Domínguez, Raúl; Santos, Hugo Miguel; Bebianno, Maria João; García-Barrera, Tamara; Gómez-Ariza, José Luis; Capelo, José Luis

    2016-12-15

    Estuaries are very important ecosystems with great ecological and economic value, but usually highly impacted by anthropogenic pressure. Thus, the assessment of pollution levels in these habitats is critical in order to evaluate their environmental quality. In this work, we combined complementary metallomic and proteomic approaches with the aim to monitor the effects of environmental pollution on Scrobicularia plana clams captured in three estuarine systems from the south coast of Portugal; Arade estuary, Ria Formosa and Guadiana estuary. Multi-elemental profiling of digestive glands was carried out to evaluate the differential pollution levels in the three study areas. Then, proteomic analysis by means of two-dimensional gel electrophoresis and mass spectrometry revealed twenty-one differential proteins, which could be associated with multiple toxicological mechanisms induced in environmentally stressed organisms. Accordingly, it could be concluded that the combination of different omic approaches presents a great potential in environmental research.

  18. Abundance of Vibrio cholerae, V. vulnificus, and V. parahaemolyticus in oysters (Crassostrea virginica) and clams (Mercenaria mercenaria) from Long Island sound.

    Science.gov (United States)

    Jones, Jessica L; Lüdeke, Catharina H M; Bowers, John C; DeRosia-Banick, Kristin; Carey, David H; Hastback, William

    2014-12-01

    Vibriosis is a leading cause of seafood-associated morbidity and mortality in the United States. Typically associated with consumption of raw or undercooked oysters, vibriosis associated with clam consumption is increasingly being reported. However, little is known about the prevalence of Vibrio spp. in clams. The objective of this study was to compare the levels of Vibrio cholerae, Vibrio vulnificus, and Vibrio parahaemolyticus in oysters and clams harvested concurrently from Long Island Sound (LIS). Most probable number (MPN)-real-time PCR methods were used for enumeration of total V. cholerae, V. vulnificus, V. parahaemolyticus, and pathogenic (tdh(+) and/or trh(+)) V. parahaemolyticus. V. cholerae was detected in 8.8% and 3.3% of oyster (n = 68) and clam (n = 30) samples, with levels up to 1.48 and 0.48 log MPN/g in oysters and clams, respectively. V. vulnificus was detected in 97% and 90% of oyster and clam samples, with median levels of 0.97 and -0.08 log MPN/g, respectively. V. parahaemolyticus was detected in all samples, with median levels of 1.88 and 1.07 log MPN/g for oysters and clams, respectively. The differences between V. vulnificus and total and pathogenic V. parahaemolyticus levels in the two shellfish species were statistically significant (P V. vulnificus and total and pathogenic V. parahaemolyticus are more prevalent and are present at higher levels in oysters than in hard clams. Additionally, the data suggest differences in vibrio populations between shellfish harvested from different growing area waters within LIS. These results can be used to evaluate and refine illness mitigation strategies employed by risk managers and shellfish control authorities.

  19. First identification of the neurotoxin homoanatoxin-a from mats of Hydrocoleum lyngbyaceum (marine cyanobacterium) possibly linked to giant clam poisoning in New Caledonia.

    Science.gov (United States)

    Méjean, Annick; Peyraud-Thomas, Caroline; Kerbrat, Anne Sophie; Golubic, Stjepko; Pauillac, Serge; Chinain, Mireille; Laurent, Dominique

    2010-10-01

    We report the first identification of homoanatoxin-a from benthic marine cyanobacteria (Hydrocoleum lyngbyaceum) samples collected in Lifou (Loyalty Islands, New Caledonia), where cases of giant clams (Tridacna maxima) intoxications were recorded during a severe ciguatera fish poisoning outbreak. Homoanatoxin-a was also detected in extracts of giant clams harvested in the surroundings of the contaminated area suggesting the possible link between these poisoning events and the occurrence of potentially neurotoxic Hydrocoleum. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  1. End-to-End Simulation for a Forest-Dedicated Full-Waveform Lidar Onboard a Satellite Initialized from Airborne Ultraviolet Lidar Experiments

    OpenAIRE

    Xiaoxia Shang; Patrick Chazette

    2015-01-01

    In order to study forests at the global scale, a detailed link budget for a lidar system onboard satellite is presented. It is based on an original approach coupling airborne lidar observations and an end-to-end simulator. The simulator is initialized by airborne lidar measurements performed over temperate and tropical forests on the French territory, representing a wide range of forests ecosystems. Considering two complementary wavelengths of 355 and 1064 nm, the end-to-end simulator compute...

  2. Inbreeding depression on growth and survival of full-sib family of Manila clam ( Ruditapes philippinarum)

    Science.gov (United States)

    Huo, Zhongming; Li, Na; Zhang, Xuekai; Li, Ying; Yan, Xiwu; Yang, Feng

    2017-02-01

    In present study, the inbreeding depression ( ID) of growth and survival of Manila clam (Ruditapes philippinarum) was investigated at larval and juvenile stages. Nine inbred families ( A 2, B 2, C 2, D 2, E 2, F 2, G 2, H 2 and I 2) were established by mating within nine full-sib families with expected inbreeding coefficient of 0.25. Inbred families showed significant differences in shell length and hatching rate of D-larvae (straight-hinged larvae). The larvae of the nine inbred families grew slower than those of control group ( CG), and their ID value ranged from 0.81% ± 6.09% to 16.10% ± 1.49%. The ID value of larval survival rate varied between 27.47% ± 9.36% and 70.50% ± 13.66%. The ID was also detected for juvenile growth in A 2, B 2, C 2, and D 2, which ranged from 4.60 ± 2.21 to 17.71 ± 7.73. The A 2 family maintained the highest juvenile survival rate, whereas the other inbred families exhibited ID values varying between 62.79% ± 4.54% and 96.14% ± 0.87%. The linear relationship of estimated ID between growth and survival was negatively correlated ( R = -0.434, P < 0.05). The results of this study suggested that the ID of growth was common at the larval stage but was less prevalent at juvenile stage. In contrast, the ID of survival increased from larval to juvenile stage. A better understanding of the effect of inbreeding may aid to selective breeding of Manila clam.

  3. Recruitment constraints in Singapore's fluted giant clam (Tridacna squamosa population--a dispersal model approach.

    Directory of Open Access Journals (Sweden)

    Mei Lin Neo

    Full Text Available Recruitment constraints on Singapore's dwindling fluted giant clam, Tridacna squamosa, population were studied by modelling fertilisation, larval transport, and settlement using real-time hydrodynamic forcing combined with knowledge of spawning characteristics, larval development, behaviour, and settlement cues. Larval transport was simulated using a finite-volume advection-diffusion model coupled to a three-dimensional hydrodynamic model. Three recruitment constraint hypotheses were tested: 1 there is limited connectivity between Singapore's reefs and other reefs in the region, 2 there is limited exchange within Singapore's Southern Islands, and 3 there exist low-density constraints to fertilisation efficacy (component Allee effects. Results showed that connectivity among giant clam populations was primarily determined by residual hydrodynamic flows and spawning time, with greatest chances of successful settlement occurring when spawning and subsequent larval dispersal coincided with the period of lowest residual flow. Simulations suggested poor larval transport from reefs located along the Peninsular Malaysia to Singapore, probably due to strong surface currents between the Andaman Sea and South China Sea combined with a major land barrier disrupting larval movement among reefs. The model, however, predicted offshore coral reefs to the southeast of Singapore (Bintan and Batam may represent a significant source of larvae. Larval exchange within Singapore's Southern Islands varied substantially depending on the locations of source and sink reefs as well as spawning time; but all simulations resulted in low settler densities (2.1-68.6 settled individuals per 10,000 m(2. Poor fertilisation rates predicted by the model indicate that the low density and scattered distribution of the remaining T. squamosa in Singapore are likely to significantly inhibit any natural recovery of local stocks.

  4. DC Cancellation As a Method of Generating a $t^{2}$ Response and of Solving the Radial Nonobservability Problem in a Concentric Free-Falling Two-Sphere Equivalence-Principle Experiment in a Drag-Free Satellite

    CERN Document Server

    Lange, B O

    2000-01-01

    An Equivalence-Principle (EP) experiment using a sphere surrounded by a spherical shell both completely unsupported and free-falling in a drag-free satellite has never been seriously considered because: 1) it has not been known how to independently measure the positions of the shell and the solid sphere with sufficient accuracy, 2) the position difference in orbit due to an EP violation only grows as t whereas the largest disturbance grows as t^{3/2}, and 3) it is not possible to distinguish between a small EP violation and a slight difference in the semi-major axes of the orbits. In a drag-free satellite spinning perpendicular to the orbit plane, two fixed spherical masses whose connecting line parallels the satellite spin axis can generate a DC gravity gradient at test masses located between them which cancels the combined gravity gradient of the earth and differential centrifugal force. With perfect cancellation, the non observability problem vanishes and the response grows as t^2 along a line which always...

  5. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment%星载高功率固态功放关键技术与实验研究

    Institute of Scientific and Technical Information of China (English)

    武小坡; 赵海洋; 奚松涛

    2014-01-01

    该文结合某星载集中式固态发射机的高功率固态功率放大器,从星载应用着手,重点从高功率密度热设计、微放电防护设计、电磁兼容性设计等方面介绍了星载高功率固态功放关键性技术的设计方法,并且通过相关的真空环境试验验证了功率放大器组件设计方法的正确性和真空环境适应性。%Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  6. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  7. Thermal dependence of clearance and metabolic rates in slow- and fast-growing spats of manila clam Ruditapes philippinarum.

    Science.gov (United States)

    Tamayo, David; Ibarrola, Irrintzi; Navarro, Enrique

    2013-10-01

    Thermal dependence of clearance rate (CR: l h(-1)), standard (SMR: J h(-1)) and routine metabolic rates (RMR: J h(-1)), were analyzed in fast (F)- and slow (S)-growing juveniles of the clam Ruditapes philippinarum. Physiological rates were measured at the maintenance temperature (17 °C), and compared with measurements performed at 10 and 24 °C after 16 h and 14 days to analyze acute and acclimated responses, respectively. Metabolic rates (both RMR and SMR) differed significantly between F and S seeds, irrespective of temperature. Mass-specific CRs were not different for F and S seeds but were significantly higher in F clams for rates standardized according to allometric size-scaling rules. Acute thermal dependency of CR was equal for F and S clams: mean Q 10 were ≈3 and 2 in temperature ranges of 10-17 and 17-24 °C, respectively. CR did not change after 2 weeks of acclimation to temperatures. Acute thermal effects on SMR were similar in both groups (Q 10 ≈ 1 and 1.6 in temperature ranges of 10-17 and 17-24 °C, respectively). Large differences between groups were found in the acute thermal dependence of RMR: Q 10 in F clams (≈1.2 and 1.9 at temperature ranges of 10-17 and 17-24 °C, respectively) were similar to those found for SMR (Q 10 = 1.0 and 1.7). In contrast, RMR of S clams exhibited maximum thermal dependence (Q 10 = 3.1) at 10-17 °C and become depressed at higher temperatures (Q 10 = 0.9 at 17-24 °C). A recovery of RMR in S clams was recorded upon acclimation to 24 °C. Contrasting metabolic patterns between fast and slow growers are interpreted as a consequence of differential thermal sensitivity of the fraction of metabolism associated to food processing and assimilation.

  8. Tactical Satellite 3

    Science.gov (United States)

    Davis, T. M.; Straight, S. D.; Lockwook, R. B.

    2008-08-01

    Tactical Satellite 3 is an Air Force Research Laboratory Science and Technology (S&T) initiative that explores the capability and technological maturity of small, low-cost satellites. It features a low cost "plug and play" modular bus and low cost militarily significant payloads - a Raytheon developed Hyperspectral imager and secondary payload data exfiltration provided by the Office of Naval Research. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a potential concept of operations for future acquisitions. The key objectives are rapid launch and on-orbit checkout, theater commanding, and near-real time theater data integration. It will also feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the satellite modular bus initiative. Planned for a late summer 2008 launch, the TacSat-3 spacecraft will collect and process images and then downlink processed data using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. An international program, the United Kingdom Defence Science and Technology Laboratory (DSTL) and Australian Defence Science and Technology Organisation (DSTO) plan to participate in TacSat-3 experiments.

  9. DC cancellation as a method of generating a t2-response and of solving the radial position error in a concentric free-falling two-sphere equivalence-principle experiment in a drag-free satellite

    Science.gov (United States)

    Lange, Benjamin

    2010-09-01

    This paper presents a new method for doing a free-fall equivalence-principle (EP) experiment in a satellite at ambient temperature which solves two problems that have previously blocked this approach. By using large masses to change the gravity gradient at the proof masses, the orbit dynamics of a drag-free satellite may be changed in such a way that the experiment can mimic a free-fall experiment in a constant gravitational field on the earth. An experiment using a sphere surrounded by a spherical shell both completely unsupported and free falling has previously been impractical because (1) it is not possible to distinguish between a small EP violation and a slight difference in the semi-major axes of the orbits of the two proof masses and (2) the position difference in the orbit due to an EP violation only grows as t whereas the largest disturbance grows as t3/2. Furthermore, it has not been known how to independently measure the positions of a shell and a solid sphere with sufficient accuracy. The measurement problem can be solved by using a two-color transcollimator (see the main text), and since the radial-position-error and t-response problems arise from the earth's gravity gradient and not from its gravity field, one solution is to modify the earth's gravity gradient with local masses fixed in the satellite. Since the gravity gradient at the surface of a sphere, for example, depends only on its density, the gravity gradients of laboratory masses and of the earth unlike their fields are of the same order of magnitude. In a drag-free satellite spinning perpendicular to the orbit plane, two fixed spherical masses whose connecting line parallels the satellite spin axis can generate a dc gravity gradient at test masses located between them which cancels the combined gravity gradient of the earth and differential centrifugal force. With perfect cancellation, the position-error problem vanishes and the response grows as t2 along a line which always points toward

  10. Long-term toxicity of hexabromocyclododecane (HBCDD) to the benthic clam Macoma balthica (L.) from the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Smolarz, Katarzyna, E-mail: oceksm@univ.gda.pl [University of Gdansk, Institute of Oceanography, Laboratory of Ecosystem Functioning, al Pilsudskiego 46, 81-378 Gdynia (Poland); Soedertoern University College, School of Life Sciences, Alfred Nobels alle 7, 141 89 Huddinge (Sweden); Berger, Agata [University of Gdansk, Institute of Oceanography, Laboratory of Ecosystem Functioning, al Pilsudskiego 46, 81-378 Gdynia (Poland)

    2009-11-27

    The world's largest brackish water sea area, the Baltic Sea, is considered to be one of the most polluted seas of the world. Many new pollutants are constantly entering the environment, such as brominated flame-retardants (BFRs). BFRs represent a group of compounds that structurally resemble hydrophobic organic contaminants, but only scarce data about their toxicity to marine organism exist. Thus, the purpose of this study was to analyze long-term in vivo cytotoxicity and genotoxicity of hexabromocyclodododecane (HBCDD) to exposed marine invertebrates using a suite of cytogenetic biomarkers. This included a set of nuclear and nucleolar characteristics and the micronucleus test. The use of those parameters reflects different mechanisms of nuclear activity regulation in cells (as a parameter of cytotoxicity) and measures subcellular processes. The induction of nuclear abnormalities (like the formation of micronuclei) was also employed here as a parameter of genotoxicity. In order to reflect the proliferative and metabolic activity of the cells the number of argylophillic nucleolar organiser regions (NORs) in interphase cells was scored. Over a period of 50 days an in vivo exposure experiment with a clam Macoma balthica and different concentrations of HBCDD (nominal concentrations of 0, 100 and 250 {mu}g/l) with three replicates each was performed. Gill cells were used as 'sentinel systems' considering specificity in metabolism, repair mechanisms, adaptative response and cell proliferation. A significant increase in nuclear and nucleolar abnormalities and in the frequency of dead cells was observed during the duration of the experiment with the highest peak occurring 10 days after exposure for nuclear abnormalities and 20-30 days after exposure for malfunction of ribosomal genes (NORs) (GLM analyses and Spearman correlation, p < 0.05). Thus, the induction of micronuclei and other nuclear abnormalities reflected the toxic potential of HBCDD to marine

  11. Applications of Communications Satellites in Higher Education.

    Science.gov (United States)

    Morgan, Robert P.

    Early experiments with the ATS-1 and ATS-3 satellites utilized one way and two way audio for a variety of university purposes, and several different television modes were employed in the ATS-6 satellite. Among the higher education activities on ATS-6 were inservice teacher education and the facilitation of regionalized medical education. A college…

  12. Developmental Transcriptome Analysis and Identification of Genes Involved in Larval Metamorphosis of the Razor Clam, Sinonovacula constricta.

    Science.gov (United States)

    Niu, Donghong; Wang, Fei; Xie, Shumei; Sun, Fanyue; Wang, Ze; Peng, Maoxiao; Li, Jiale

    2016-04-01

    The razor clam Sinonovacula constricta is an important commercial species. The deficiency of developmental transcriptomic data is becoming the bottleneck of further researches on the mechanisms underlying settlement and metamorphosis in early development. In this study, de novo transcriptome sequencing was performed for S. constricta at different early developmental stages by using Illumina HiSeq 2000 paired-end (PE) sequencing technology. A total of 112,209,077 PE clean reads were generated. De novo assembly generated 249,795 contigs with an average length of 585 bp. Gene annotation resulted in the identification of 22,870 unigene hits against the NCBI database. Eight unique sequences related to metamorphosis were identified and analyzed using real-time PCR. The razor clam reference transcriptome would provide useful information on early developmental and metamorphosis mechanisms and could be used in the genetic breeding of shellfish.

  13. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Softshell Clam.

    Science.gov (United States)

    1986-08-01

    for locomotion (Green 1975). Although The fertilized egg takes about usually attached to the substrate by 12 h to develop into the planktonic the byssus...observed clumped distribution of when fried, steamed in broth, or baked juvenile clams is therefore, according in fire pits under seaweed (Hanks to Lucy...bivalves, settlement of recently metamorphosed planktonic larvae is the only signi- sources of mortality (predation, ficant source of recruitment. Size

  14. Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

    Science.gov (United States)

    Nichols, S. Jerrine; Black, M.G.

    1994-01-01

    There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

  15. Combined Effects of Temperature and Seston Concentration on the Physiological Energetics of the Manila Clam Ruditapes philippinarum.

    Directory of Open Access Journals (Sweden)

    Hee Yoon Kang

    Full Text Available The suspension-feeding Manila clam Ruditapes philippinarum is a native species of the western Pacific that is now widely distributed around the globe because of its commercial importance. To determine the adaptive physiological responses to changing thermal and nutritional conditions, clearance, filtration, feces production, ammonium excretion, respiration rates, and scope for growth (SFG were measured in adult clams. The clams were exposed to 24 treatments involving the combination of four water temperatures (8, 13, 18, and 23°C and six concentrations of suspended particulate matter (SPM: 9.5 to 350.5 mg L(-1. Physiological rates were standardized by using the mean (480 mg of tissue dry weights of experimental clams using allometric equations between physiological variables and tissue dry weight. Higher clearance rates were recorded at higher temperatures and lower SPM concentrations, and these rates decreased with increasing SPM concentration at individual temperatures. Consumed energy increased with increasing temperature and SPM concentration, peaking at around 100-200 mg L(-1 at 18-23°C. Whereas fecal energy was largely determined by SPM concentration, ammonia excretion was mainly governed by temperature. Respiration rate studies revealed a predominant quadratic effect of temperature on the metabolism, indicating a lack of acclimatory adjustment of metabolic rate to rising temperature. SFG values were positive under almost all the treatment conditions and were much higher at higher SPM concentrations (> 45 mg L(-1, with the highest level being recorded at 18°C and 100-200 mg L(-1 SPM. Increased filtration rate offset the increased metabolic cost at warm temperatures. Our holistic findings suggest that a high degree of physiological plasticity allows R. philippinarum to tolerate the wide range of temperatures and SPM concentrations that are found in tidal flats, accounting in part for the successful distribution of this species over a

  16. Combined Effects of Temperature and Seston Concentration on the Physiological Energetics of the Manila Clam Ruditapes philippinarum.

    Science.gov (United States)

    Kang, Hee Yoon; Lee, Young-Jae; Choi, Kwang-Sik; Park, Hyun Je; Yun, Sung-Gyu; Kang, Chang-Keun

    2016-01-01

    The suspension-feeding Manila clam Ruditapes philippinarum is a native species of the western Pacific that is now widely distributed around the globe because of its commercial importance. To determine the adaptive physiological responses to changing thermal and nutritional conditions, clearance, filtration, feces production, ammonium excretion, respiration rates, and scope for growth (SFG) were measured in adult clams. The clams were exposed to 24 treatments involving the combination of four water temperatures (8, 13, 18, and 23°C) and six concentrations of suspended particulate matter (SPM: 9.5 to 350.5 mg L(-1)). Physiological rates were standardized by using the mean (480 mg) of tissue dry weights of experimental clams using allometric equations between physiological variables and tissue dry weight. Higher clearance rates were recorded at higher temperatures and lower SPM concentrations, and these rates decreased with increasing SPM concentration at individual temperatures. Consumed energy increased with increasing temperature and SPM concentration, peaking at around 100-200 mg L(-1) at 18-23°C. Whereas fecal energy was largely determined by SPM concentration, ammonia excretion was mainly governed by temperature. Respiration rate studies revealed a predominant quadratic effect of temperature on the metabolism, indicating a lack of acclimatory adjustment of metabolic rate to rising temperature. SFG values were positive under almost all the treatment conditions and were much higher at higher SPM concentrations (> 45 mg L(-1)), with the highest level being recorded at 18°C and 100-200 mg L(-1) SPM. Increased filtration rate offset the increased metabolic cost at warm temperatures. Our holistic findings suggest that a high degree of physiological plasticity allows R. philippinarum to tolerate the wide range of temperatures and SPM concentrations that are found in tidal flats, accounting in part for the successful distribution of this species over a wide variety

  17. Freshwater clam extract supplementation improves wound healing by decreasing the tumor necrosis factor α level in blood.

    Science.gov (United States)

    Peng, Yi-Chi; Fwu-LinYang; Subeq, Yi-Maun; Tien, Chin-Chieh; Lee, Ru-Ping

    2017-03-01

    The freshwater clam (Corbicula fluminea) is a widely consumed functional food in Asia and is traditionally used to improve health and either prevent or treat inflammation-related diseases. Numerous studies have proposed that freshwater clams act to prevent and attenuate inflammatory responses, and also serve as a possible inhibitor to systemic inflammation. However, there is limited information available about the effects of freshwater clams on wound healing. The present study investigated the influence of freshwater clam extract (FCE) on wound healing and inflammatory responses in a cutaneous incision model. Sixteen rats were used and divided into two groups: the FCE group and the normal saline (NS) group. The rats underwent dorsal full-thickness skin excisional wounds (diameter 20 × 10 mm). FCE or NS was administered for oral feeding twice daily for 14 days after wounding. Blood samples were taken and analyzed, and wound areas were measured at several time points during the 2 weeks after excision. On day 14 after wounding, skin biopsies from the wound sites were sent for histological examination. Treatment with FCE (71.63 ± 9.51 pg mL(-1) ) decreased tumor necrosis factor-α levels compared to the NS group (109.86 ± 12.55 pg mL(-1) ) after wounding at 3 h (P wound areas of the NS group (23.9%) were larger than those in the FCE group (8.26%) on day 14 (P wound healing process. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Relationship between gonad maturation and heavy metal accumulation in the clam, Galatea paradoxa (Born 1778) from the Volta estuary, Ghana.

    Science.gov (United States)

    Adjei-Boateng, D; Obirikorang, K A; Amisah, S; Madkour, H A; Otchere, F A

    2011-12-01

    The relationship between gonadal development and the concentrations of four heavy metals Mn, Zn, Fe and Hg in the tissues of the clam Galatea paradoxa was evaluated at the Volta estuary, Ghana, over an 18-month period. Metal concentrations in the clam tissues were highly variable over the sampling period and seemed to be influenced by the reproductive cycle of the clam. Mn concentrations varied over a wide range from 49 to 867 μg/g and exhibited a significant positive correlation with gonadal development (p = 0.0146, r(2) = 0.3190). Zn and Fe concentrations ranged from 13 to 59 μg/g and 79 to 484 μg/g, respectively and both revealed negative relationships between gonad development and metal accumulation (Zn (p = 0.0554, r(2) = 0.0554) and Fe (p = 0.1040, r(2) = 0.1567)). Hg concentrations ranged from 0.026 to 0.059 μg/g over the sampling period and exhibited a slight positive relationship between gonadal development and metal accumulation (p = 0.0861, r(2) = 0.1730).

  19. Toxicological effects induced by cadmium in gills of Manila clam ruditapes philippinarum using NMR-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Linbao; Liu, Xiaoli; You, Liping; Zhou, Di [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); The Graduate School of Chinese Academy of Sciences, Beijing (China); Yu, Junbao; Zhao, Jianmin; Wu, Huifeng [Key Laboratory of Coastal Zone Environment Processes, CAS, Shandong Provincial Key Laboratory of Coastal Zone Environment Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai (China); Feng, Jianghua [Department of Electronic Science, Fujian Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen (China)

    2011-11-15

    Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 {mu}g L{sup -1}) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 {mu}g L{sup -1}) and high (40 {mu}g L{sup -1}) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR-based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Dynamic changes in the accumulation of metabolites in brackish water clam Corbicula japonica associated with alternation of salinity.

    Science.gov (United States)

    Koyama, Hiroki; Okamoto, Seiji; Watanabe, Naoki; Hoshino, Naoshige; Jimbo, Mitsuru; Yasumoto, Ko; Watabe, Shugo

    2015-03-01

    The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river varies daily due to a strong effect of tidal waters. In the present study, we dissected the gill and foot muscle of brackish water clam collected from these areas, and subjected them to metabolome analysis by capillary electrophoresis-time-of-flight mass spectrometry. More than 200 metabolites including free amino acids, peptides and organic acids were identified, and their amounts from the foot muscle tend to be higher than those from the gill. The principal component analysis revealed that the amount of each metabolite was different among sampling areas and between the gill and foot muscle, whereas no apparent differences were observed between male and female specimens. When the metabolites in the female clam at high salinity were compared with those at low salinity, concentrations of β-alanine, choline, γ-aminobutyric acid, ornithine and glycine betaine were found to be changed in association with salinity. We also compared various metabolites in relation to metabolic pathways, suggesting that many enzymes were involved in their changes depending on salinity.

  1. Study of the toxic effects of flame retardant PBDE-47 on the clam Chamelea gallina (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Salvatora Angela Angioni

    2013-03-01

    Full Text Available The purpose of the study is to evaluate the effects of 2,2',4,4'-tetrabromodiphenylether (PBDE-47 on the Chamelea gallina clam (according to current commercial regulations: Venus gallina. PBDEs, which are used as flame retardants in various industrial products, are classed as hazardous substances by Directive 2011/65/EU. They are bioaccumulative compounds, considered to be endocrine disruptors, genotoxic, neurotoxic and practically ubiquitous, and their concentration in the environment has considerably increased in recent years. The aim of this study is to establish the effects of PBDE-47 on Chamelea gallina: toxic power and any harmful effects on the gonads, bioaccumulation capacity in the tissues, and possible entry into the food chain. The research used 96-hour and 21-day experimental tests on clams housed in filtered seawater. The tests were preceded by a period of acclimatisation of the molluscs lasting five to seven days. The clams were fed on seaweed (Dunaliella tertiolecta. The choice of the toxic compound PBDE-47 was based on the high concentration, among the congeners of PBDE, found in some aquatic species. The study demonstrated that the concentration of the contaminant used did not alter the vital functions, cause significant levels of mortality or lead to evident alteration in the gonads of Chamelea gallina. However, the research demonstrated the bioaccumulation capacity of the bivalve mollusc, allowing PBDE-47 to enter the food chain.

  2. Surface and internal microstructure damage of He-ion-irradiated CLAM steel studied by cross-sectional transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, P.P. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhan, Q., E-mail: qzhan@mater.ustb.edu.cn [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Fu, Z.Y.; Wei, Y.P. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Y.M. [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Wang, F.M. [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Ohnuki, S. [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Wan, F.R. [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-11-15

    Good understanding of blistering and embrittlement mechanism depends on good investigation of surface and internal microstructure damage of gas-ion-irradiated materials. Internal and surface microstructure of He{sup +} ion irradiated CLAM steel were examined by cross-sectional transmission electron microscopy combining focused ion beam. Variation of helium bubble density and size distribution versus depth in CLAM steel after high dose helium irradiation at room temperature was investigated. The average size of helium bubble increased within 100–400 nm but decreased near the non-irradiated matrix with the increase of depth, while the density followed a reverse trend. The formation and growth mechanism of helium bubble is different at different irradiation depth. The formation of a zone of large bubbles under the surface is the main reason of surface blistering and flaking. Helium induced irradiation swelling and surface blistering at low temperature were also discussed. - Highlights: • Microstructure of helium irradiated CLAM steel was investigated by FIB and TEM. • The nucleation of helium bubble was controlled by both different mechanisms. • The substructure of surface blisters has been analyzed in detail by XTEM. • Helium induced surface blistering and irradiation swelling have been discussed.

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

    Science.gov (United States)

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

    2017-01-01

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

  4. Mercury and methylmercury contamination in surficial sediments and clams of a coastal lagoon (Pialassa Baiona, Ravenna, Italy)

    Science.gov (United States)

    Trombini, Claudio; Fabbri, Daniele; Lombardo, Marco; Vassura, Ivano; Zavoli, Elisabetta; Horvat, Milena

    2003-11-01

    The Ramsar site Pialassa Baiona is an intertidal brackish lagoon lying 5 km north of the city of Ravenna and covering a surface area of about 1100 ha. From 1958 to 1976 Pialassa Baiona was heavily impacted by industrial pollution; mercury, polycyclic aromatic hydrocarbons, polymers were among the most important pollutants which nowadays contaminate the sedimentary compartment. Following earlier investigations on total mercury (THg) distribution and bioavailability, this study is focused on mercury speciation in sediments and clams. Methylmercury ( MMHg) concentrations were determined in surface sediments (0-5 cm) in different seasons, and compared to THg. Selected sediments were subjected to a sequential extraction procedure to study solid state THg distribution. Operationally, three fractions of inorganic mercury were defined: mobile mercury ( Hgm), humic acid complexed mercury ( Hgha), and sulphide-bound mercury ( Hgs). THg and MMHg concentrations in sediments ranged in the 0.2-250 μg g -1 and 0.13-45 ng g -1 d.w. intervals, respectively. MMHg/THg ratios were higher in summer as well as in sites where the THg burden was lower; the highest MMHg/THg values were observed in Chiaro del Pontazzo, an area subjected to a drastic reduction of salinity. THg and MMHg concentrations were also determined in tissues of clams ( Tapes philippinarum) collected in the lagoon. MMHg in clams felt in the 180-470 ng g -1 interval and accounts for 72-95% of tissue THg.

  5. Satellite data compression

    CERN Document Server

    Huang, Bormin

    2011-01-01

    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  6. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  7. A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

    Science.gov (United States)

    Pan, Hai

    1999-08-01

    Kinneret is a 166-km2 lake located in Northern Israel, in the central part of the Jordan Valley, a corridor running from north to south, between the Galilee hills in the west and the Golan Heights in the east. Both the Galilee hills and the Golan Heights reach an elevation of about 400 m above mean sea level (MSL), and the lake is about -210 m (MSL). North of the lake is the mountainous area of the Hermon, culminating at about 2800 m (MSL). About 120 km south of it is the Dead Sea, which is about -410 m (MSL), and about 45 km west of it is the Mediterranean Sea. The complexity of the terrain, combined with relatively arid soil and various ground covers surrounding the lake, results in a very complicated system of atmospheric and lake processes. To understand this system, especially the processes affecting the atmosphere and lake dynamics and thermodynamics, and their effects on Lake Kinneret evaporation, a coupled lake-atmosphere model (CLAM) was developed and applied to the lake region. The CLAM is based on the Regional Atmospheric Modeling System (RAMS) and the oceanic S-coordinate Rutgers University Model (SCRUM). Energy, mass, and momentum are conserved at the interface between the atmosphere and the lake, and appropriate balance equations are applied there. In the atmospheric module, two nested grids are employed to simulate Northern Israel at a resolution of 4 x 4 km2, and the near-lake region at a resolution of 1 x 1 km 2. Synoptic conditions obtained from the National Meteorological Center (NMC) reanalysis are assimilated by the model. Soil moisture, which appears to have a significant impact on atmospheric circulation in this region, was transformed from the normalized difference vegetation index (NDVI). Observations collected during two summers above and inside the lake emphasize the good capability of CLAM to simulate surface fluxes and other microclimatic conditions, as well as lake temperature and currents. Although the lake is small (about 12-km wide

  8. Results of the BSE experiment

    Science.gov (United States)

    Iwasaki, K.; Yamamoto, M.; Kurakake, Y.; Kinoshita, S.

    Results of satellite broadcasting experiments carried out using the BSE (Japan's Medium-scale Broadcasting Satellite for Experimental Purpose) are described. Consideration is given to the following experiments: the reception of radio waves from the satellite, radio wave attenuation and scattering, the uplink power control experiment, experiments with transportable earth stations, the transmission of FM-TV signals, and frequency sharing between the broadcasting satellite and broadcasting services in the 12 GHz band.

  9. The usability of ark clam shell (Anadara granosa) as calcium precursor to produce hydroxyapatite nanoparticle via wet chemical precipitate method in various sintering temperature.

    Science.gov (United States)

    Khiri, Mohammad Zulhasif Ahmad; Matori, Khamirul Amin; Zainuddin, Norhazlin; Abdullah, Che Azurahanim Che; Alassan, Zarifah Nadakkavil; Baharuddin, Nur Fadilah; Zaid, Mohd Hafiz Mohd

    2016-01-01

    This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries .

  10. End-to-End Simulation for a Forest-Dedicated Full-Waveform Lidar Onboard a Satellite Initialized from Airborne Ultraviolet Lidar Experiments

    Directory of Open Access Journals (Sweden)

    Xiaoxia Shang

    2015-04-01

    Full Text Available In order to study forests at the global scale, a detailed link budget for a lidar system onboard satellite is presented. It is based on an original approach coupling airborne lidar observations and an end-to-end simulator. The simulator is initialized by airborne lidar measurements performed over temperate and tropical forests on the French territory, representing a wide range of forests ecosystems. Considering two complementary wavelengths of 355 and 1064 nm, the end-to-end simulator computes the performance of spaceborne lidar systems for different orbits. The analysis is based on forest structural (tree top height, quadratic mean canopy height and optical (forest optical thickness parameters. Although an ultraviolet lidar appears to be a good candidate for airborne measurements, our results show that the limited energy is not favorable for spaceborne missions with such a wavelength. A near infrared wavelength at 1064 nm is preferable, requiring ~100 mJ laser emitted energy, which is in agreement with current and future spaceborne missions involving a lidar. We find that the signal-to-noise ratio at the ground level to extract both the structural and optical parameters of forests must be larger than 10. Hence, considering the presence of clouds and aerosols in the atmosphere and assuming a stationary forest, a good detection probability of 99% can be reached when 4 or 5 satellite revisits are considered for a lidar system onboard the ISS or ICESat, respectively. This concerns ~90% of forest covers observed from the lidar, which have an optical thickness less than 3.

  11. Satellite observations of ground water changes in New Mexico

    Science.gov (United States)

    In 2002 NASA launched the Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE consists of two satellites with a separation of about 200 km.  By accurately measuring the separation between the twin satellites, the differences in the gravity field can be determined. Monthly observ...

  12. Inexpensive land-use maps extracted from satellite data

    Science.gov (United States)

    Barney, T. W.; Barr, D. J.; Elifrits, C. D.; Johannsen, C. J.

    1979-01-01

    Satellite images are interpretable with minimal skill and equipment by employing method which uses false color composite print of image of area transmitted from Landsat satellite. Method is effective for those who have little experience with satellite imagery, little time, and little money available.

  13. Experimental millimeter-wave satellite communications system

    Science.gov (United States)

    Suzuki, Yoshiaki; Shimada, Masaaki; Arimoto, Yoshinori; Shiomi, Tadashi; Kitazume, Susumu

    This paper describes an experimental system of millimeter-wave satellite communications via Japan's Engineering Test Satellite-VI (ETS-VI) and a plan of experiments. Two experimental missions are planned using ETS-VI millimeter-wave (43/38 GHz bands) transponder, considering the millimeter-wave characteristics such as large transmission capacity and possibility to construct a small earth station with a high gain antenna. They are a personal communication system and an inter-satellite communication system. Experimental system including the configuration and the fundamental functions of the onboard transponder and the outline of the experiments are presented.

  14. Toxicity and the fractional distribution of trace metals accumulated from contaminated sediments by the clam Scrobicularia plana exposed in the laboratory and the field

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, J., E-mail: judit.kalman@uca.es [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bonnail-Miguel, E. [Department of Physical-Chemistry, University of Cadiz, Poligono Industrial Rio San Pedro s/n, 11,510 Puerto Real, Cadiz (Spain); Smith, B.D. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Bury, N.R. [Division of Diabetes and Nutritional Science, King' s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH (United Kingdom); Rainbow, P.S. [Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2015-02-15

    The relationship between the subcellular distribution of accumulated toxic metals into five operational fractions (subsequently combined into presumed detoxified and non-detoxified components) and toxicity in the clam Scrobicularia plana was investigated under different laboratory exposures. Clams were exposed to metal contaminated media (water and diet) and analysed for the partitioning of accumulated As, Cu and Zn into subcellular fractions. In general, metallothionein-like proteins, metal-rich granules and cellular debris in different proportions acted as main storage sites of accumulated metals in the clam soft tissues for these three metals. No significant differences were noted in the accumulation rates of As, Cu and Zn of groups of individuals with or without apparent signs of toxicity after up to 30 days of exposure to naturally contaminated sediment mixtures. There was, however, an increased proportional accumulation of Cu in the non-detoxified fraction with increased Cu accumulation rate in the clams, suggesting that the Cu uptake rate from contaminated sediments exceeded the combined rates of elimination and detoxification of Cu, with the subsequent likelihood for toxic effects in the clams. - Highlights: • Scrobicularia plana accumulated As, Cu and Zn from naturally toxic sediments. • Toxic metals were accumulated in detoxified and non-detoxified components. • Cu accumulation in the non-detoxified pool increased with increased Cu uptake rate. • Cu uptake rate exceeded combined loss and detoxification rates to cause toxicity.

  15. Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins

    Directory of Open Access Journals (Sweden)

    Thanh-Luu Pham

    2015-01-01

    Full Text Available We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana. Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin-LReq L−1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT, superoxide dismutase (SOD and glutathione S-transferase (GST. Clam accumulated MCs (up to 12.7 ± 2.5 μg g−1 dry weight (DW of free MC and 4.2 ± 0.6 μg g−1 DW of covalently bound MC. Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO provisional tolerable daily intake (0.04 μg kg−1 day−1, suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

  16. Development of a Taqman real-time PCR assay for rapid detection and quantification of Vibrio tapetis in extrapallial fluids of clams

    Directory of Open Access Journals (Sweden)

    Adeline Bidault

    2015-12-01

    Full Text Available The Gram-negative bacterium Vibrio tapetis is known as the causative agent of Brown Ring Disease (BRD in the Manila clam Venerupis (=Ruditapes philippinarum. This bivalve is the second most important species produced in aquaculture and has a high commercial value. In spite of the development of several molecular methods, no survey has been yet achieved to rapidly quantify the bacterium in the clam. In this study, we developed a Taqman real-time PCR assay targeting virB4 gene for accurate and quantitative identification of V. tapetis strains pathogenic to clams. Sensitivity and reproducibility of the method were assessed using either filtered sea water or extrapallial fluids of clam injected with the CECT4600T V. tapetis strain. Quantification curves of V. tapetis strain seeded in filtered seawater (FSW or extrapallial fluids (EF samples were equivalent showing reliable qPCR efficacies. With this protocol, we were able to specifically detect V. tapetis strains down to 1.125 101 bacteria per mL of EF or FSW, taking into account the dilution factor used for appropriate template DNA preparation. This qPCR assay allowed us to monitor V. tapetis load both experimentally or naturally infected Manila clams. This technique will be particularly useful for monitoring the kinetics of massive infections by V. tapetis and for designing appropriate control measures for aquaculture purposes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Jumpei; Sakamoto, Wataru [Division of Applied Biosciences, Graduate School of Agriculture, Kyoto Univ., Kyoto (Japan)

    1998-07-01

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

  18. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  19. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  20. Fossil clam shells reveal unintended carbon cycling consequences of Colorado River management

    Science.gov (United States)

    Smith, Jansen A.; Auerbach, Daniel A.; Flessa, Karl W.; Flecker, Alexander S.; Dietl, Gregory P.

    2016-09-01

    Water management that alters riverine ecosystem processes has strongly influenced deltas and the people who depend on them, but a full accounting of the trade-offs is still emerging. Using palaeoecological data, we document a surprising biogeochemical consequence of water management in the Colorado River basin. Complete allocation and consumptive use of the river's flow has altered the downstream estuarine ecosystem, including the abundance and composition of the mollusc community, an important component in estuarine carbon cycling. In particular, population declines in the endemic Colorado delta clam, Mulinia coloradoensis, from 50-125 individuals m-2 in the pre-dam era to three individuals m-2 today, have likely resulted in a reduction, on the order of 5900-15 000 t C yr-1 (4.1-10.6 mol C m-2 yr-1), in the net carbon emissions associated with molluscs. Although this reduction is large within the estuarine system, it is small in comparison with annual global carbon emissions. Nonetheless, this finding highlights the need for further research into the effects of dams, diversions and reservoirs on the biogeochemistry of deltas and estuaries worldwide, underscoring a present need for integrated water and carbon planning.

  1. Shell matrix proteins of the clam, Mya truncata: Roles beyond shell formation through proteomic study.

    Science.gov (United States)

    Arivalagan, Jaison; Marie, Benjamin; Sleight, Victoria A; Clark, Melody S; Berland, Sophie; Marie, Arul

    2016-06-01

    Mya truncata, a soft shell clam, is presented as a new model to study biomineralization through a proteomics approach. In this study, the shell and mantle tissue were analysed in order to retrieve knowledge about the secretion of shell matrix proteins (SMPs). Out of 67 and 127 shell and mantle proteins respectively, 16 were found in both shell and mantle. Bioinformatic analysis of SMP sequences for domain prediction revealed the presence of several new domains such as fucolectin tachylectin-4 pentraxin-1 (FTP), scavenger receptor, alpha-2-macroglobulin (α2 M), lipocalin and myosin tail along with previously reported SMP domains such as chitinase, carbonic anhydrase, tyrosinase, sushi, and chitin binding. Interestingly, these newly predicted domains are attributed with molecular functions other than biomineralization. These findings suggest that shells may not only act as protective armour from predatory action, but could also actively be related to other functions such as immunity. In this context, the roles of SMPs in biomineralization need to be looked in a new perspective.

  2. Gill damage and neurotoxicity of ammonia nitrogen on the clam Ruditapes philippinarum.

    Science.gov (United States)

    Cong, Ming; Wu, Huifeng; Yang, Haiping; Zhao, Jianmin; Lv, Jiasen

    2017-04-01

    Ammonia nitrogen has been a potential menace to aquatic animals along the coastline of China. Presently, the toxicological effects of ammonia nitrogen were mainly concentrated on fishes, while little attention has been paid to molluscs. In this study, the clam Ruditapes philippinarum was used as the target animal to investigate the toxic effects of ammonia nitrogen. Our results showed that ammonia exposure could significantly reduce the integrity of lysosomes in a dose-dependent manner. Metabolite analysis revealed that exposure doses and duration time of ammonia nitrogen could affect the variation profiles of gill metabolites. In detail, branched chain amino acids, glutamate, choline and phosphocholine were significantly decreased after a one-day exposure. Inosine and phenylalanine were found significantly increased and ATP was decreased after a three-day exposure. The changes of metabolites implied that metabolisms of muscle element, neurotransmission and cell apoptosis of gill tissues would be affected by ammonia exposure. Such inferences were supported by the diminished muscle element, decreased concentrations of catecholamines and increased apoptosis rates, respectively. Therefore, we take advantage of metabolomics integrated with conventional biological assays to find out that ammonia exposure could cause lysosome instability, metabolic disturbance, aberrant gill structures and changes to neurotransmitters, and would result in mollusk gill dysfunction in feeding, respiration and immunity.

  3. Overfishing population characteristics of razor clam, Ensis macha, from Independencia Bay, Peru, in 2004 year

    Directory of Open Access Journals (Sweden)

    Juan Tarazona

    2011-05-01

    Full Text Available Quantitative monthly samplings, in 2004, were carried out to estimate the density and biomass of Ensis macha (Molina 1782, from Morro Quemado area, Bay Independence, Pisco. The present study analyzes biometric relationships, growth parameters and somatic production using the ELEFAN I routine and the Crisp’s method. During the year 2004 the rate of exploitation (E= 0.69 y-1 was significantly bigger than the values of 2003 and the monthly landings (maximum of 335 t and fishing effort (maximum of 848 trips were twice increased. These changes induced in the same year a significant decrease of population mean density (D= 54.13 ind. m-2 and the halfway reduction of somatic production (P= 81.99 gAFDW m-2 y-1 and P/B rate (0.38 y-1 values, regarding the values of the previous year. Also, a significant increment of total mortality rate (2.84 y-1 and the fishing mortality rate (1.97 y-1 were twice increased, regarding the previous year. It is assumed that the population of razor clams already was a overfishing commercial resource in the 2003 and that the increment of fishing pressure in the 2004, particularly during the second semester, intensified its overfishing resource condition.

  4. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    KAUST Repository

    Piló, D.

    2016-11-03

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters.

  5. Seasonal dynamics of biomarkers in infaunal clam Macoma balthica from the Gulf of Riga (Baltic Sea)

    Science.gov (United States)

    Barda, Ieva; Purina, Ingrida; Rimsa, Elina; Balode, Maija

    2014-01-01

    Biomarkers are often regarded as “early warning” signals of environmental pollution; however seasonal changes are mentioned as one of the most important factor that influences the activity of biomarkers. The aim of our study was to assess the importance of seasonal variation of selected contaminant biomarkers in Macoma balthica to provide background information for further environmental surveys in the Gulf of Riga. Seasonal variation of biomarkers (acetylcholinesterase (AChE), catalase (CAT), glutathione reductase (GR) and glutathione-S-transferase (GST)) was measured in infaunal clam M. balthica from the southern part of the Gulf of Riga. The majority of biomarkers (GST, CAT and GR) showed strong seasonal variability; however only CAT and GR were found to be significantly related to environmental factors (near-bottom oxygen, salinity and temperature). Integrated biomarker response (IBR) index indicated that the most stressed condition of M. balthica is during August and May. The highest values of IBR were found near the mouth of the River Daugava, suggesting the impact of environmental pollution on the benthic animals.

  6. Molecular phylogenetics and historical biogeography amid shifting continents in the cockles and giant clams (Bivalvia: Cardiidae).

    Science.gov (United States)

    Herrera, Nathanael D; Ter Poorten, Jan Johan; Bieler, Rüdiger; Mikkelsen, Paula M; Strong, Ellen E; Jablonski, David; Steppan, Scott J

    2015-12-01

    Reconstructing historical biogeography of the marine realm is complicated by indistinct barriers and, over deeper time scales, a dynamic landscape shaped by plate tectonics. Here we present the most extensive examination of model-based historical biogeography among marine invertebrates to date. We conducted the largest phylogenetic and molecular clock analyses to date for the bivalve family Cardiidae (cockles and giant clams) with three unlinked loci for 110 species representing 37 of the 50 genera. Ancestral ranges were reconstructed using the dispersal-extinction-cladogenesis (DEC) method with a time-stratified paleogeographic model wherein dispersal rates varied with shifting tectonics. Results were compared to previous classifications and the extensive paleontological record. Six of the eight prior subfamily groupings were found to be para- or polyphyletic. Cardiidae originated and subsequently diversified in the tropical Indo-Pacific starting in the Late Triassic. Eastern Atlantic species were mainly derived from the tropical Indo-Mediterranean region via the Tethys Sea. In contrast, the western Atlantic fauna was derived from Indo-Pacific clades. Our phylogenetic results demonstrated greater concordance with geography than did previous phylogenies based on morphology. Time-stratifying the DEC reconstruction improved the fit and was highly consistent with paleo-ocean currents and paleogeography. Lastly, combining molecular phylogenetics with a rich and well-documented fossil record allowed us to test the accuracy and precision of biogeographic range reconstructions.

  7. Morphometry, growth and reproduction of an Atlantic population of the razor clam Ensis macha (Molina, 1782

    Directory of Open Access Journals (Sweden)

    Pedro J. Barón

    2004-06-01

    Full Text Available Ensis macha is a razor clam distributed throughout the coasts of southern Argentina and Chile. Even though it represents a valuable fishery resource, the exploitation of its Atlantic populations has begun only in recent years. This study provides the first estimates of growth rate, an interpretation of the reproductive cycle on the coast of the northern Argentine Patagonia and an analysis of the species morphometry. Growth was estimated by direct observation of growth rings on the valves by two observers. The reproductive cycle was interpreted by the analysis of temporal change of oocyte size frequency distributions. Parameter estimations for the von Bertalanffy equations respectively obtained by observers 1 and 2 were 154 and 153.7 mm for L?, 0.25 and 0.20 yr-1 for k, and -0.08 and -0.72 yr for t0. Two spawning peaks were detected: September-November 1999 and May-June 2000. However, mature females were found all year round. An abrupt change in the relationship between shell length and height was detected at 11.2 mm length.

  8. Physical proximity may promote lateral acquisition of bacterial symbionts in vesicomyid clams.

    Directory of Open Access Journals (Sweden)

    Carole Decker

    Full Text Available Vesicomyid clams harbor intracellular sulfur-oxidizing bacteria that are predominantly maternally inherited and co-speciate with their hosts. Genome recombination and the occurrence of non-parental strains were recently demonstrated in symbionts. However, mechanisms favoring such events remain to be identified. In this study, we investigated symbionts in two phylogenetically distant vesicomyid species, Christineconcha regab and Laubiericoncha chuni, which sometimes co-occur at a cold-seep site in the Gulf of Guinea. We showed that each of the two species harbored a single dominant bacterial symbiont strain. However, for both vesicomyid species, the symbiont from the other species was occasionally detected in the gills using fluorescence in situ hybridization and gene sequences analyses based on six symbiont marker genes. Symbiont strains co-occurred within a single host only at sites where both host species were found; whereas one single symbiont strain was detected in C. regab specimens from a site where no L. chuni individuals had been observed. These results suggest that physical proximity favored the acquisition of non-parental symbiont strains in Vesicomyidae. Over evolutionary time, this could potentially lead to genetic exchanges among symbiont species and eventually symbiont displacement. Symbiont densities estimated using 3D fluorescence in situ hybridization varied among host species and sites, suggesting flexibility in the association despite the fact that a similar type of metabolism is expected in all symbionts.

  9. Food sources of the Manila clam Ruditapes philippinarum in intertidal areas: evidence from stable isotope analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liqiang; YAN Xiwu; YANG Feng

    2013-01-01

    Based on stable isotope analysis,we characterized the dietary regime of the Manila clam Ruditapesphilippinarum inhabiting intertidal areas along the Liaodong Peninsula,Northern China.Samples,including particulate organic matter (POM; n=30),benthic microalgae (BMI; n=30) and R.philippinarum (n=60),were collected from six sampling sites displaying the same ecological conditions.Of the two primary food sources,POM was more depleted in δ13C (-20.61‰ to-22.89‰) than BMI was (-13.90‰ to-16.66‰).With respect to 15N,BMI was more enriched (2.90‰ to 4.07‰) than POM was (4.13‰ to 5.12‰).The δ13C values of R.philippinarum ranged from-18.78‰ to-19.35‰ and the δ15N values from 7.96‰ to 8.63‰,which were intermediate between the POM and BMI values.In a two-source isotope mixing model,we estimated the relative contributions of POM and BMI to the diet of R.philippinarum to be 74.2% and 25.8%,respectively.We conclude that R.philippinarum feeds mainly on POM,and BMI is also an important supplemental food source in intertidal areas.

  10. Hemoglobins Likely Function as Peroxidase in Blood Clam Tegillarca granosa Hemocytes.

    Science.gov (United States)

    Wang, Sufang; Yu, Xiaopei; Lin, Zhihua; Zhang, Shunqin; Xue, Liangyi; Xue, Qinggang; Bao, Yongbo

    2017-01-01

    Hemoglobins are a group of respiratory proteins principally functioning in transport of oxygen and carbon dioxide in red blood cells of all vertebrates and some invertebrates. The blood clam T. granosa is one of the few invertebrates that have hemoglobin-containing red hemocytes. In the present research, the peroxidase activity of T. granosa hemoglobins (Tg-Hbs) was characterized and the associated mechanism of action was deciphered via structural comparison with other known peroxidases. We detected that purified Tg-Hbs catalyzed the oxidation of phenolic compounds in the presence of exogenous H2O2. Tg-Hbs peroxidase activity reached the maximum at pH 5 and 35°C and was inhibited by Fe(2+), Cu(2+), SDS, urea, and sodium azide. Tg-Hbs shared few similarities in amino acid sequence and overall structural characteristics with known peroxidases. However, the predicted structure at their heme pocket was highly similar to that of horseradish peroxidase (HRP) and myeloperoxidase (MPO). This research represented the first systemic characterization of hemoglobin as a peroxidase.

  11. Rhodopirellula rosea sp. nov., a novel bacterium isolated from an ark clam Scapharca broughtonii.

    Science.gov (United States)

    Roh, Seong Woon; Lee, Hae-Won; Yim, Kyung June; Shin, Na-Ri; Lee, Jina; Whon, Tae Woong; Lim, Na-Lae; Kim, Daekyung; Bae, Jin-Woo

    2013-06-01

    A novel Gram-negative, motile, and ovoid-shaped strain, LHWP3(T), which belonged to the family Planctomycetaceae in the phylum Planctomycetes, was isolated from a dead ark clam Scapharca broughtonii collected during a mass mortality event on the south coast of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the isolate was most closely related to the type strain of Rhodopirellula baltica, with a shared 16S rRNA gene sequence similarity of 94.8%. The isolate grew optimally at 30°C in 4-6% (w/v) NaCl, and at pH 7. The major isoprenoid quinone was menaquinone-6 (MK-6). The dominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, and unidentified polar lipids. The predominant cellular fatty acids were C16:0, C18:1 ω9c, and C18:0. The genomic DNA G+C content of strain LHWP3(T) was 53.0 mol%. Based on polyphasic taxonomic analyses, strain LHWP3(T) should be classified as a novel species in the genus Rhodopirellula in the family Planctomycetaceae, for which the name Rhodopirellula rosea sp. nov. is proposed. The type strain is LHWP3(T) (=KACC 15560(T) =JCM 17759(T)).

  12. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    Science.gov (United States)

    Piló, D; Carvalho, S; Pereira, P; Gaspar, M B; Leitão, A

    2017-01-15

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Hemoglobins Likely Function as Peroxidase in Blood Clam Tegillarca granosa Hemocytes

    Science.gov (United States)

    Yu, Xiaopei; Lin, Zhihua; Xue, Liangyi

    2017-01-01

    Hemoglobins are a group of respiratory proteins principally functioning in transport of oxygen and carbon dioxide in red blood cells of all vertebrates and some invertebrates. The blood clam T. granosa is one of the few invertebrates that have hemoglobin-containing red hemocytes. In the present research, the peroxidase activity of T. granosa hemoglobins (Tg-Hbs) was characterized and the associated mechanism of action was deciphered via structural comparison with other known peroxidases. We detected that purified Tg-Hbs catalyzed the oxidation of phenolic compounds in the presence of exogenous H2O2. Tg-Hbs peroxidase activity reached the maximum at pH 5 and 35°C and was inhibited by Fe2+, Cu2+, SDS, urea, and sodium azide. Tg-Hbs shared few similarities in amino acid sequence and overall structural characteristics with known peroxidases. However, the predicted structure at their heme pocket was highly similar to that of horseradish peroxidase (HRP) and myeloperoxidase (MPO). This research represented the first systemic characterization of hemoglobin as a peroxidase. PMID:28182094

  14. Preliminary study of HDA coating on CLAM steel followed by high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoqiang, E-mail: newboy.chen@163.com; Huang, Qunying; Yan, Zilin; Song, Yong; Liu, Shaojun; Jiang, Zhizhong

    2013-11-15

    A hot-dip aluminizing process is expected to produce aluminide coatings on structural materials to resist tritium permeation, corrosion, and magnetohydrodynamic (MHD) effects in the fusion reactor blanket. China Low Activation Martensitic (CLAM) steel, which is the candidate structural material for the LiPb blanket system in China, was coated with pure aluminum and with an Al–Si alloy. Factors affecting the thickness and morphology of the aluminide coatings were studied. After the hot-dipping treatment, FeAl{sub 3} and Fe{sub 2}Al{sub 5} were observed at the Al/steel interface. The existence of silicon in the molten aluminum suppressed the growth of Fe{sub 2}Al{sub 5}, built up the thickness of FeAl{sub 3} slightly, and contributed to reducing the thickness of the intermetallic layer. The brittle phase of Fe{sub 2}Al{sub 5} had completely transformed to ductile phases of FeAl{sub 2}, FeAl and α-Fe(Al) after high temperature heat-treatment in air. Kirkendall voids were found in the diffusion layer, due to the rapid interdiffusion of iron and aluminum during oxidation. Cracks and pores were observed on the coating surface and at the interlayer. Grazing incidence X-ray diffraction indicates the presence of α-Al{sub 2}O{sub 3} in the oxide layer.

  15. In vitro exposure of haemocytes of the clam Ruditapes philippinarum to titanium dioxide (TiO2) nanoparticles: nanoparticle characterisation, effects on phagocytic activity and internalisation of nanoparticles into haemocytes.

    Science.gov (United States)

    Marisa, Ilaria; Marin, Maria Gabriella; Caicci, Federico; Franceschinis, Erica; Martucci, Alessandro; Matozzo, Valerio

    2015-02-01

    The continuous growth of nanotechnology and nano-industries, the considerable increase of products containing nanoparticles (NPs) and the potential release of NPs in aquatic environments suggest a need to study NP effects on aquatic organisms. In this context, in vitro assays are commonly used for evaluating or predicting the negative effects of chemicals and for understanding their mechanisms of action. In this study, a physico-chemical characterisation of titanium dioxide NPs (n-TiO2) was performed, and an in vitro approach was used to investigate the effects of n-TiO2 on haemocytes of the clam Ruditapes philippinarum. In particular, the effects on haemocyte phagocytic activity were evaluated in two different experiments (with and without pre-treatment of haemocytes) by exposing cells to P25 n-TiO2 (0, 1 and 10 μg/mL). In addition, the capability of n-TiO2 to interact with clam haemocytes was evaluated with a transmission electron microscope (TEM). In this study, n-TiO2 particles showed a mean diameter of approximately 21 nm, and both anatase (70%) and rutile (30%) phases were revealed. In both experiments, n-TiO2 significantly decreased the phagocytic index compared with the control, suggesting that NPs are able to interfere with cell functions. The results of the TEM analysis support this hypothesis. Indeed, we observed that TiO2 NPs interact with cell membranes and enter haemocyte cytoplasm and vacuoles after 60 min of exposure. To the best of our knowledge, this is the first study demonstrating the internalisation of TiO2 NPs into R. philippinarum haemocytes. The present study can contribute to the understanding of the mechanisms of action of TiO2 NPs in bivalve molluscs, at least at the haemocyte level.

  16. Exploiting Satellite Remote-Sensing Data in Fine Particulate Matter Characterization for Serving the Environmental Public Health Tracking Network (EPHTN): The HELIX-Atlanta Experience and NPOESS Implications

    Science.gov (United States)

    Al-Hamdan, Mohammad Z.; Crosson, William L.; Limaye, Ashutosh S.; Rickman, Douglas L.; Quattrochi, Dale A.; Estes, Maurice G.; Qualters, Judith R.; Sinclair, Amber H.; Tolsma, Dennis D.; Adeniyi, Kafayat A.

    2008-01-01

    As part of the U.S. National Environmental Public Health Tracking Network (EPHTN), the National Center for Environmental Health (NCEH) at the U.S. Centers for Disease Control and Prevention (CDC) led a project in collaboration with the National Aeronautics and Space Administration (NASA) Marshall Space Flight Center (MSFC) called Health and Environment Linked for Information Exchange (HELIX-Atlanta). Under HELIX-Atlanta, pilot projects were conducted to develop methods to better characterize exposure; link health and environmental datasets; and analyze spatial/temporal relationships. This paper describes and demonstrates different techniques for surfacing daily environmental hazards data of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM(sub 2.5) for the purpose of integrating respiratory health and environmental data for the CDC's pilot study of HELIX-Atlanta. It describes a methodology for estimating ground-level continuous PM(sub 2.5) concentrations using spatial surfacing techniques and leveraging NASA Moderate Resolution Imaging Spectrometer (MODIS) data to complement the U.S. Environmental Protection Agency (EPA) ground observation data. The study used measurements of ambient PM(sub 2.5) from the EPA database for the year 2003 as well as PM(sub 2.5) estimates derived from NASA's MODIS data. Hazard data have been processed to derive the surrogate exposure PM(sub 2.5) estimates. The paper has shown that merging MODIS remote sensing data with surface observations of PM(sub 2.5), may provide a more complete daily representation of PM(sub 2.5), than either data set alone would allow, and can reduce the errors in the PM(sub 2.5) estimated surfaces. Future work in this area should focus on combining MODIS column measurements with profile information provided by satellites like the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The Visible Infrared Imager/Radiometer Suite (VIIRS) and the Aerosol

  17. The experiment of satellite navigation of unmanned aerial vehicle%无人机卫星导航的接收定位故障实验

    Institute of Scientific and Technical Information of China (English)

    张岩

    2016-01-01

    Flight to provide accurate orientation and position coordinates,and according to the attitude information of flight state is predicted,which is the combination of position and orientation navigation system requires the completion of the task.With the relevant competition positioning software applications, in the greatest degree guarantee the autonomous flight of aircraft.But in the precise positioning,there will always be a failure,which requires the reasonable analysis of the resource failure and according to the results of correlation analysis, optimize UAV satellite navigation and positioning technology.%向飞行提供精确的方向和位置坐标,并且根据姿态信息对飞机飞行的状态进行预测,这些就是组合定位定向导航系统需要完成的任务。结合了相关竞争能定位软件的应用,在最大程度上保证了无人飞机的自主飞行。但是在精确定位中,总会有故障发生,这就需要将故障资源合理分析,并针对相关分析结果,优化无人机卫星导航定位技术。

  18. Satellite-Delivered Learning.

    Science.gov (United States)

    Arnall, Gail C.

    1987-01-01

    Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

  19. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  20. China's Recoverable Satellites

    Institute of Scientific and Technical Information of China (English)

    Tang Boehang

    2008-01-01

    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  1. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  2. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  3. Seasonal Changes in Glycogen Contents in Various Tissues of the Edible Bivalves, Pen Shell Atrina lischkeana, Ark Shell Scapharca kagoshimensis, and Manila Clam Ruditapes philippinarum in West Japan

    Directory of Open Access Journals (Sweden)

    Tatsuya Yurimoto

    2015-01-01

    Full Text Available The types of tissues accumulating glycogen and seasonal changes in glycogen content were investigated in the following shell species: pen shell Atrina lischkeana, ark shell Scapharca kagoshimensis, and Manila clam Ruditapes philippinarum. Comparison of the results showed that the adductor muscle or foot was the main glycogen reservoir and the levels varied seasonally. The adductor muscle in the pen shell showed higher glycogen content during spring and lower content during autumn. The ark shell, on the other hand, showed higher content during winter and spring and lower content during summer and autumn, while the Manila clam showed higher glycogen content during spring and summer and lower content during autumn and winter. These results revealed that the adductor muscle in pen shells and the foot in ark shells and Manila clams act as the main storage tissues for glycogen in the three species studied and that these tissues are suitable to analyze glycogen prevalence to estimate individual physiological condition.

  4. Favored use of anti-predator netting (APN) applied for the farming of clams leads to little benefits to industry while increasing nearshore impacts and plastics pollution.

    Science.gov (United States)

    Bendell, L I

    2015-02-15

    An overview of the efficacy of anti-predator netting (APN) used by the shellfish industry is presented. There is little support that the currently favored APN effectively protects farmed clams from predators. Evidence does suggest that APN leads to impacts and pollution. APN is an attractant for predators, e.g., crabs, by providing a refuge within Ulva sp. which attaches onto the surface of APN. APN entrains silt and organic matter and increases sediment temperatures degrading habitat underneath the APN. APN present hazards to fish and wildlife and is a source of plastics to the marine environment. The continued use of ineffective APN does not serve either the environment or industry well, and many of these issues could be addressed through the alternate use of "ancient" technology used by aboriginal people to maintain clam gardens; building of rock walls optimizing the amount of clam habitat thereby increasing numbers without the use of APN.

  5. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  6. Geodetic Secor Satellite

    Science.gov (United States)

    1974-06-01

    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  7. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  8. Insights into the establishment of the Manila clam on a tidal flat at the southern end of an introduced range in Southern California, USA.

    Directory of Open Access Journals (Sweden)

    Drew M Talley

    Full Text Available Coastal ecosystem modifications have contributed to the spread of introduced species through alterations of historic disturbance regimes and resource availability, and increased propagule pressure. Frequency of occurrence of the Manila clam (Venerupis phillipinarum, Veneridae in Southern California estuaries has increased from absent or sparse to common since the mid-1990s. Potential invasion vectors include seafood sales and aquaculture, and spread from established northern populations over decades. The clam's post-settlement habitat preferences are, however, uncertain in this region. Our project aimed to identify factors associated with established patches of the clam within a bay toward the southern end of this introduced range. During summer 2013, we sampled 10 tidal flat sites in Mission Bay, San Diego; each containing an area with and without hard structure (e.g., riprap, boulders. We measured likely environmental influences (e.g., sediment variables, distance to ocean. Manila clam densities across the bay were most strongly associated with site, where highest densities were located in the northern and/or back halves of the bay; and weakly correlated with lower porewater salinities. Within sites, Manila clam density was enhanced in the presence of hard structure in most sites. Prevailing currents and salinity regimes likely contribute to bay wide distributions, while hard structures may provide suitable microhabitats (refuge from predators and physical stress and larval entrapment within sites. Results provide insights into decisions about future shoreline management efforts. Finally, we identify directions for future study to better understand and therefore predict patterns of establishment of the Manila clam in the southern portion of its introduced range.

  9. Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

    Science.gov (United States)

    Dubert, Javier; Nelson, David R; Spinard, Edward J; Kessner, Linda; Gomez-Chiarri, Marta; da Costa, Fiz; Prado, Susana; Barja, Juan L

    2016-01-01

    Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was

  10. The impact of selection on population genetic structure in the clam Meretrix petechialis revealed by microsatellite markers.

    Science.gov (United States)

    Lu, Xia; Wang, Hongxia; Li, Yan; Liu, Baozhong

    2016-02-01

    The aim of our work is to evaluate the impact of mass selection on genetic structure in artificially closed populations of the clam Meretrix petechialis. In the present study, we performed mass selection over four generations (from 2004 to 2010) on two clam populations [shell features of purple lines (SP) and black dots (SB)] and analyzed their temporal genetic variation and structure using microsatellite makers. The two closed populations originated from the natural Shandong population (SD); thus, a natural SD population (10SD) was used to detect the current genetic structure after 6 years of natural selection. The results showed that the genetic diversity of the four generations of SB and SP was gradually reduced but remained at relatively high levels (SB, A = 18.9.4-16.8, Ho = 0.7389-0.6971, and He = 0.8897-0.8591; SP, A = 20.0-17.8, Ho = 0.7512-0.7043, and He = 0.8938-0.8625), which has not been reduced compared with that of the 10SD population (A = 17.8, Ho = 0.6803, and He = 0.8302). The Ne estimates for the two populations were almost at the same levels as the actual numbers of parental individuals. In addition, a low inbreeding coefficient was detected in the two populations (SB, 0.00201-0.00639; SP, 0.00176-0.00541). Based on the results, the present mass selection has not made a large impact on the population genetic structure of the closed populations. The present investigation provides important information for the development of management strategies for genetic breeding of the clam.

  11. Expression of a symbiosis-specific gene in Symbiodinium type A1 associated with coral, nudibranch and giant clam larvae

    KAUST Repository

    Mies, M.

    2017-05-24

    Symbiodinium are responsible for the majority of primary production in coral reefs and found in a mutualistic symbiosis with multiple animal phyla. However, little is known about the molecular signals involved in the establishment of this symbiosis and whether it initiates during host larval development. To address this question, we monitored the expression of a putative symbiosis-specific gene (H+-ATPase) in Symbiodinium A1 ex hospite and in association with larvae of a scleractinian coral (Mussismilia hispida), a nudibranch (Berghia stephanieae) and a giant clam (Tridacna crocea). We acquired broodstock for each host, induced spawning and cultured the larvae. Symbiodinium cells were offered and larval samples taken for each host during the first 72 h after symbiont addition. In addition, control samples including free-living Symbiodinium and broodstock tissue containing symbionts for each host were collected. RNA extraction and RT-PCR were performed and amplified products cloned and sequenced. Our results show that H+-ATPase was expressed in Symbiodinium associated with coral and giant clam larvae, but not with nudibranch larvae, which digested the symbionts. Broodstock tissue for coral and giant clam also expressed H+-ATPase, but not the nudibranch tissue sample. Our results of the expression of H+-ATPase as a marker gene suggest that symbiosis between Symbiodinium and M. hispida and T. crocea is established during host larval development. Conversely, in the case of B. stephanieae larvae, evidence does not support a mutualistic relationship. Our study supports the utilization of H+-ATPase expression as a marker for assessing Symbiodinium-invertebrate relationships with applications for the differentiation of symbiotic and non-symbiotic associations. At the same time, insights from a single marker gene approach are limited and future studies should direct the identification of additional symbiosis-specific genes, ideally from both symbiont and host.

  12. Best management strategies for sustainable giant clam fishery in French Polynesia islands: answers from a spatial modeling approach.

    Directory of Open Access Journals (Sweden)

    Simon Van Wynsberge

    Full Text Available The giant clam Tridacna maxima has been largely overexploited in many tropical regions over the past decades, and was therefore listed in appendix II of the Convention of International Trade in Endangered Species (CITES in 1985. In French Polynesia, several atolls and islands harbor the world's highest stocks of giant clams in very shallow and accessible areas, which are therefore highly vulnerable to fishing pressure. The local fishery authority (i.e., Direction des Resources Marines or "DRM" implemented several management schemes in 2002 to control and regulate fishing pressure. However, for further decisions DRM was missing a sensitivity analysis on the effectiveness of the possible management actions. Here, we report on the use of a deterministic Viable Population Analysis (VPA and spatially-explicit age-based population model that simulated the 30-year trajectory of a Tridacna maxima stock under different management approaches. Specifically, given various scenarios of intra-island larval dispersal, we tested which of No-take-Areas (NTAs, rotational closures, size limits, quotas, and restocking schemes would lead to the highest future stocks in Tubuai and Raivavae, two exploited islands of the Austral archipelago. For both islands, stock abundances were estimated in 2004/2010 and 2005/2010 respectively, and natural mortalities were assessed previously only in Tubuai. When compared to field data, the model successfully predicted the 2010 stocks for Tubuai, but proved to be less reliable for Raivavae, where natural mortality rates may well be different from those on Tubuai. For Tubuai, the spatial model suggested that reducing fishing effort (through fixed quotas and banning fishing below the 12 cm size limit (as currently implemented were the most effective management actions to sustain T. maxima populations into the future. Implementing NTAs was of poor effectiveness. NTAs increased giant clam stock inside the protected area, but also

  13. Japanese propagation experiments with ETS-5

    Science.gov (United States)

    Ikegami, Tetsushi

    1989-01-01

    Propagation experiments for maritime, aeronautical, and land mobile satellite communications were performed using Engineering Test Satellite-Five (ETS-5). The propagation experiments are one of major mission of Experimental Mobile Satellite System (EMSS) which is aimed for establishing basic technology for future general mobile satellite communication systems. A brief introduction is presented for the experimental results on propagation problems of ETS-5/EMSS.

  14. Settlement, mortality and growth of the asari clam (Ruditapes philippinarum) for a collapsed population on a tidal flat in Nakatsu, Japan

    Science.gov (United States)

    Tezuka, Naoaki; Kamimura, Satomi; Hamaguchi, Masami; Saito, Hajime; Iwano, Hideki; Egashira, Junichi; Fukuda, Yuichi; Tawaratsumida, Takahiko; Nagamoto, Atsushi; Nakagawa, Koichi

    2012-04-01

    Although fluctuation and decline in bivalve populations have been reported worldwide, the underlying processes are not yet fully understood. This lack of understanding is partly due to an absence of demographic information for the early post-settlement period. This is the case particularly for annual production of the asari clam (also commonly known as the Manila clam, Ruditapes philippinarum) in Japan, which has greatly decreased in recent years. A remarkable decrease has been observed in the Nakatsu tidal flat, where current yields are less than 0.02% of the maximum yield. Possible explanations for this decline are: 1. limitation on recruitment due to overfishing; and 2. the demographic processes of growth and mortality have been altered by environmental changes, such as rise in seawater temperature or decrease in phytoplankton abundance. However, because of a lack of demographic information (e.g., the initial densities of larval settlement and mortality and growth rates post-settlement), the reasons for the decline, and the relative importance of each period in the life cycle in determining population abundance, remain unclear. Despite the decline, we observed high levels of recruitment of 0-year-class clams on the Nakatsu tidal flat in spring 2005, where more than 10,000 individuals m- 2 3-5 mm in shell length, estimated to have settled during the previous autumn, were observed. To obtain demographic information on the Nakatsu clams, we investigated two factors. First, we investigated the distribution of the 0-year-class clams and their rate of change in density as a combination of mortality, emigration and immigration on the whole tidal flat after a year. Second, we investigated the rate of change in the density and growth of clams after settlement in the center of the flat for 3 years. The rate of decrease in the density of the 0-year-class clams over the whole tidal flat after a year was greater at the stations where the initial density was higher. This

  15. Gravimetric geodesy and sea surface topography studies by means of satellite-to-satellite tracking and satellite altimetry

    Science.gov (United States)

    Siry, J. W.

    1972-01-01

    A satellite-to-satellite tracking experiment is planned between ATS-F and GEOS-C with a range accuracy of 2-meters and a range rate accuracy of 0.035 centimeters per second for a 10-second integration time. This experiment is planned for 1974. It is anticipated that it will improve the spatial resolution of the satellite geoid by half an order of magnitude to about 6 degrees. Longer integration times should also permit a modest increase in the acceleration resolution. Satellite altimeter data will also be obtained by means of GEOS-C. An overall accuracy of 5-meters in altitude is the goal. The altimeter, per se, is expected to have an instrumental precision of about 2 meters, and an additional capability to observe with a precision of about 0.2 meters for limited periods.

  16. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Muttray, Annette, E-mail: amuttray@rescan.com [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Reinisch, Carol, E-mail: creinisch@mbl.edu [Visiting Scientist Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Miller, Jason, E-mail: j.miller@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Ernst, William, E-mail: bill.ernst@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 45 Alderney Drive, Dartmouth, NS, Canada B2Y 2N6 (Canada); Gillis, Patricia, E-mail: patty.gillis@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Losier, Melanie, E-mail: melanie.losier@ec.gc.ca [Environment Canada, Atlantic Laboratory for Environmental Testing, Environmental Science Centre, P.O. Box 23005 Moncton, NB, Canada E1A 6S8 (Canada); Sherry, James, E-mail: jim.sherry@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada)

    2012-05-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ss-endosulfan and {alpha}-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: Black-Right-Pointing-Pointer We examined leukemia prevalence in PEI clams Mya arenaria. Black

  17. First study of Vibrios in larval cultures of pullet carpet shell clam (Venerupis corrugata in hatchery

    Directory of Open Access Journals (Sweden)

    Javier Dubert Pérez

    2014-07-01

    Full Text Available Protocol for hatchery culture of the pullet carpet shell clam Venerupis corrugata spat is currently under development, as the only reliable means of providing spat to replenish natural beds or to support aquaculture activities. Among other variables, the microbiota has been demonstrated to be critical for successful bivalve culture. Shellfish hatcheries are hindered by fatal outbreaks of disease, regardless the bivalve species. These mass mortalities are mainly caused by opportunistic bacteria belonging to genus Vibrio and constitute one bottleneck for this economic activity. Different species, as V. tubiashii, V. pectenicida, V. splendidus, V. neptunius, V. ostreicida and V. bivalvicida, have been identified as responsible of mortalities in hatchery-reared larvae, affecting a wide range of bivalves. This is the first report of the microbiota associated with larval cultures of the pullet carpet shell clam. We present the results of the microbiological analyses of two larval cultures of pullet carpet shell reared in the Centro de Investigacións Mariñas (CIMA, Xunta de Galicia de Ribadeo (Galicia, NW Spain following the procedures developed in the institution. Each batch, A and B, was obtained from broodstocks collected in natural environment but in different geographical locations, the stock A (SW Galicia and the stock B (NW Galicia. Previous records of mortalities led us to divide each batch in two. One sub-batch (A1 and B1 was cultured following the routine procedures. Antibiotic was experimentally added to the other sub-batch (A2 and B2 with the aim of evaluating the effects on the culturable bacterial population (total marine bacteria and presumptive vibrios and on larval survival. Chloramphenicol, formerly the most commonly used antibiotic in bivalve hatcheries, was supplied with each change of seawater during larval development. Microbiological samples of broodstock, larvae and seawater in culture tanks were taken and processed

  18. Early development, survival and growth rates of the giant clam Tridacna crocea (Bivalvia: Tridacnidae

    Directory of Open Access Journals (Sweden)

    Miguel Mies

    2012-06-01

    Full Text Available Tridacnid clams are conspicuous inhabitants of Indo-Pacific coral reefs and are traded and cultivated for the aquarium and food industries. In the present study, daily growth rates of larvae of the giant clam Tridacna crocea were determined in the laboratory during the first week of life. Adults were induced to spawn via intra-gonadal serotonin injection through the byssal orifice. After spawning oocytes were collected, fertilized and kept in 3 L glass beakers and raceways treated with antibiotics to avoid culture contamination. Larvae were fed twice with the microalga Isochrysis galbana and zooxanthellae were also offered twice during the veliger stage (days 4 and 6. Larval length was measured using a digitizing tablet coupled to a microcomputer. Larval mortality was exponential during the first 48 hours of life declining significantly afterwards. Mean growth rate was 11.3 μm day-1, increasing after addition of symbionts to 18.0 μm day-1. Survival increased to ca. 75% after the addition of zooxanthellae. The results describe the growth curve for T. crocea larvae and suggest that the acquisition of symbionts by larvae may be useful for larval growth and survival even before larvae have attained metamorphosis.Bivalves tridacnídeos são habitantes conspícuos dos recifes da região do Indo-Pacífico e são cultivados e comercializados para os mercados alimentício e aquarista. No estudo apresentado foram determinadas as taxas de crescimento diário durante a primeira semana de vida da larva do bivalve ornamental Tridacna crocea. As matrizes foram induzidas à desova por meio de uma injeção intragonadal de serotonina realizada através do orifício bissal. Após desova, ovócitos foram coletados, fertilizados e mantidos em béqueres de vidro e tanques de fluxo contínuo tratados com antibióticos para evitar contaminação. Larvas foram alimentadas em duas ocasiões com a microalga Isochrysis galbana e zooxantelas foram oferecidas também por

  19. Effect of cadmium in the clam Ruditapes decussatus assessed by proteomic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chora, Suze [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal); University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Starita-Geribaldi, Mireille [University of Nice-Sophia Antipolis, Laboratory of Oral Microbiology, URE 01., Faculty of Odontology, Pole Universitaire Saint-Jean d' Angely, 24 avenue des Diables Bleus 06357 Nice cedex 4 (France); Guigonis, Jean-Marie [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); Samson, Michel [University of Nice-Sophia Antipolis, Plateforme Bernard Rossi - Proteome Metabolome IFR50, Nice, F-06107 (France); INSERM, Unite 638, Nice, F-06107 (France); Romeo, Michele [University of Nice-Sophia Antipolis EA 4228 ECOMERS ' Ecosystemes Cotiers Marins et Reponses aux stress' Parc Valrose, BP 71, 06108 Nice cedex 2 (France); Bebianno, Maria Joao, E-mail: mbebian@ualg.pt [University of Algarve, CIMA, Faculty of Marine and Environmental Sciences, Campus de Gambelas, 8000-139 Faro (Portugal)

    2009-10-04

    Cadmium, an environmental stressor due to its toxicity, persistence and accumulation in biota, is widespread in the aquatic environment. Cadmium accumulation kinetics have revealed that Ruditapes decussatus has a high affinity to this metal. Proteomics is an effective tool to evaluate the toxic effects of contaminants. The aim of this study was to investigate the Cd effects in the gill and digestive gland of the sentinel species R. decussatus. Protein expression profiles (PEPs) in the clam tissues exposed to Cd (40 {mu}g l{sup -1}, 21 days) were compared to unexposed ones. Cd induces major changes in tissue-specific protein expression profiles in gill and digestive gland. This tissue dependent response results mainly from differences in Cd accumulation, protein inhibition and/or autophagy. An overall decrease of protein spots was detected in both treated tissues, being higher in gill. Some of the spots more drastically altered after pollutants exposure were excised and nine were identified by micro liquid chromatography tandem mass spectrometry (LC-MS/MS). Proteins identified by homology search in databases included: three proteins (8-fold) up-regulated, one down-regulated, four suppressed and one induced. Cd induces major changes in proteins involved in cytoskeletal structure maintenance (muscle-type actin, adductor muscle actin and {beta}-tubulin), cell maintenance (Rab GDP) and metabolism (ALDH and MCAD, both identified by de novo sequencing) suggesting potential energetic change. They provide a valuable knowledge of Cd effects at biochemical and molecular levels in the gill and digestive gland of R. decussatus.

  20. Phylogeography and limited genetic connectivity in the endangered boring giant clam across the Coral Triangle.

    Science.gov (United States)

    DeBoer, Timery S; Subia, Matthew D; Erdmann, Mark V; Kovitvongsa, Katie; Barber, Paul H

    2008-10-01

    The Coral Triangle is the global center of marine biodiversity; however, its coral reefs are critically threatened. Because of the bipartite life history of many marine species with sedentary adults and dispersive pelagic larvae, designing effective marine protected areas requires an understanding of patterns of larval dispersal and connectivity among geographically discrete populations. We used mtDNA sequence data to examine patterns of genetic connectivity in the boring giant clam (Tridacna crocea) in an effort to guide conservation efforts within the Coral Triangle. We collected an approximately 485 base pair fragment of mtDNA cytochrome c oxidase 1 (CO1) from 414 individuals at 26 sites across Indonesia. Genetic structure was strong between regions (phi(ST)=0.549, p < 0.00001) with 3 strongly supported clades: one restricted to western Sumatra, another distributed across central Indonesia, and a third limited to eastern Indonesia and Papua. Even within the single largest clade, small but significant genetic structure was documented (phi(ST)=0.069, p < 0.00001), which indicates limited gene flow within and among phylogeographic regions. Significant patterns of isolation by distance indicated an average dispersal distance of only 25-50 km, which is far below dispersal predictions of 406-708 km derived from estimates of passive dispersal over 10 days via surface currents. The strong regional genetic structure we found indicates potent limits to genetic and demographic connectivity for this species throughout the Coral Triangle and provides a regional context for conservation planning. The recovery of 3 distinct evolutionarily significant units within a well-studied taxonomic group suggests that biodiversity in this region may be significantly underestimated and that Tridacna taxa may be more endangered than currently recognized.

  1. A biomineralization study of the Indo-Pacific giant clam Tridacna gigas

    Science.gov (United States)

    Gannon, M. E.; Pérez-Huerta, A.; Aharon, P.; Street, S. C.

    2017-06-01

    The giant clam, Tridacna gigas, is an important faunal component of reef ecosystems of the Indo-Pacific region. In addition to its ecological role, shells of this bivalve species are useful bioarchives for past climate and environmental reconstructions. However, the biomineralization processes involved in shell aragonite deposition are insufficiently understood. Here, we present a study of the shell microstructure of modern specimens from Palm Island, Great Barrier Reef (GBR), Australia, and Huon Peninsula, Papua New Guinea (PNG), using a combination of petrography, scanning electron microscopy, electron backscatter diffraction, Raman spectroscopy and stable carbon isotope ratios. Daily growth increments were recognizable in all specimens through ontogeny, and counting these growth lines provides a robust specimen age estimate. For the internal layers, paired increments of organized aragonitic needles and compact, oblong crystals were recognized in a specimen from PNG, whereas specimens from GBR were composed of shield-like crystals that were not definable at the microscale. The combination of nutrient availability, rainfall and solar irradiance are likely to be the most significant factors controlling shell growth and may explain the observed differences in microstructure. The external layer, identical in all specimens, was composed of dendritic microstructure that is significantly enriched in 13C compared to the internal layer, suggesting different metabolic controls on layer deposition. We propose that the mineralization of the internal and external layers is independent from each other and associated with the activity of specific mantles. Future studies using T. gigas shells as bioarchives should consider the microstructure as it reflects the environment in which the individual lived and the differences in mineralization pathways of internal and external layers.

  2. Sterilization of freeze dried manila clam (Ruditapea philippinarum) porridge for immuno-compromised patients

    Energy Technology Data Exchange (ETDEWEB)

    Song, Beom Seok; Park, Jae Nam [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-02-15

    This study was conducted to evaluate the combined effect of gamma irradiation and different conditions (vacuum packaging, antioxidant and freezing) on the microbiological and sensory characteristics of freeze dried Manila clam porridge (MCP) for immuno-compromised patient food. McP can be sterilized at 1 kGy to 10 kGy. the initial counts of total aerobic bacteria and yeast molds in the non-irradiated MCP were 2.4±0.5 and 1.2±0.3 log CFU g{sup -}'1, respectively, but gamma irradiation significantly decreased the total aerobic bacteria to below the detection limit (1 log CFU g{sup -1}) (5 kGy). Moreover, gamma irradiation effectively eliminated yeasts/molds at dose below than 1 kGy. However, gamma irradiation accelerated the increase of lipid oxidation and therefore, decreased the sensory characteristics of MCP as irradiation dose increased. to improve the sensory qualities of gamma irradiated MCP, combination treatment (vacuum packaging, 0.1% vitamin c) were applied. there was no significant difference in the overall acceptance scores between the combined-treatment sample (5.6 points) and the non-irradiated samples (6.0). the results indicate that combination treatment (vacuum packaging, 0.1% vitamin c) may help to maintain the quality of MCP. therefore, it considered that irradiation of MCP with combined treatment and this is an effective method for the consumption as a special purpose food such as for space travel or immuno-compromised patients.

  3. Ruegeria conchae sp. nov., isolated from the ark clam Scapharca broughtonii.

    Science.gov (United States)

    Lee, Jina; Whon, Tae Woong; Shin, Na-Ri; Roh, Seong Woon; Kim, Jandi; Park, Seong-Kyu; Kim, Min-Soo; Shin, Kee-Sun; Lee, Jung-Sook; Lee, Keun Chul; Kim, Young-Ok; Bae, Jin-Woo

    2012-12-01

    A slightly halophilic, Gram-negative, strictly aerobic, non-motile rod, designated TW15(T), was isolated from an ark clam in South Korea. Growth occurred at 10-37 °C, with 1-5% (w/v) NaCl and at pH 7.0-10.0. Optimal growth occurred at 25-30 °C, with 2% (w/v) NaCl and at pH 8.0. Strain TW15(T) exhibited both oxidase and catalase activities. The major fatty acids of strain TW15(T) were summed feature 8 (consisting of C(18:1)ω7c and/or C(18:1)ω6c) and 11-methyl C(18:1)ω7c. The predominant isoprenoid quinone was ubiquinone-10 (Q-10). The polar lipids of strain TW15(T) comprised phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid and five unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain TW15(T) was most closely related to Ruegeria lacuscaerulensis DSM 11314(T) (98.0% 16S rRNA gene sequence similarity). DNA-DNA relatedness with closely related strains was <52 ± 3%. The DNA G+C content was 55.7 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain TW15(T) represents a novel species of the genus Ruegeria, for which the name Ruegeria conchae sp. nov. is proposed. The type strain is TW15(T) ( = KACC 15115(T)  = JCM 17315(T)).

  4. Temporal dynamics of amino and fatty acid composition in the razor clam Ensis siliqua (Mollusca: Bivalvia)

    Science.gov (United States)

    Baptista, Miguel; Repolho, Tiago; Maulvault, Ana Luísa; Lopes, Vanessa M.; Narciso, Luis; Marques, António; Bandarra, Narcisa; Rosa, Rui

    2014-12-01

    Few studies have been conducted on the temporal dynamics of both amino acid (AA) and fatty acid (FA) profiles in marine bivalves. We investigated the seasonal variation of these compounds in the pod razor clam Ensis siliqua in relation to food availability, salinity, water temperature and reproductive cycle. AA content varied between 46.94 and 54.67 % dry weight (DW), and the AAs found in greater quantity were glutamic acid, glycine and aspartic acid. FA content varied between 34.02 and 87.94 mg g-1 DW and the FAs found in greater quantity were 16:0 and 22:6 n-3. Seasonal trends were observed for AAs and FAs. FAs increased with gametogenesis and decreased with spawning while AA content increased throughout spawning. The effect of increasing temperature and high food availability during the spawning season masked the loss of AAs resulting from gamete release. Still, a comparatively greater increase in the contents of glutamic acid and leucine with spawning indicate their possible involvement in a post-spawning gonad recovery mechanism. A post-spawning decrease in 14:0, 16:0, 16:1 n-7, 18:1 n-7 and 18:1 n-9 is indicative of the importance of these FAs in bivalve eggs. An increase in 18:3 n-3, 18:4 n-3, 20:1 n-9 and 20:2 n-6 during gametogenesis suggests their involvement in oocyte maturation. The FA 22:4 n-6, while increasing with spawning, appears to play a role in post-spawning gonad recovery. Salinity did not have an effect on the AA composition. None of the environmental parameters measured had an effect on FA composition.

  5. Demonstration on the indexes design of gravity satellite orbit parameters in the low-low satellite-to-satellite tracking mode

    Directory of Open Access Journals (Sweden)

    Liu Xiaogang

    2013-02-01

    Full Text Available Combining with the exigent demand of the development of satellite gravimetry system in China, aiming at the determination of technical indexes of gravity satellite orbit parameters, on the basis of the numerical experiments and results analysis, the design indexes of gravity satellite orbit height, inter-satellite range and the orbit inclination are analyzed and calculated, and the issues towards twin gravity satellites such as coherence requirement of the orbit semi-major axes, control requirement of the pitch angle and time interval requirement to keep twin satellites formation in mobility are discussed. Results show that the satellite orbit height is 400 km to 500 km, the inter-satellite range is about 220 km, the satellite orbit inclination is between polar orbit and sun-synchronous orbit, the semi-major axes difference of twin satellites orbit is within ±70. 146 m, the pitch angle of twin satellites is about 0.9 degree, and the time interval to keep twin satellites formation in mobility is 7 days to 15 days.

  6. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  7. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  8. Proceedings of the Mobile Satellite Conference

    Science.gov (United States)

    Rafferty, William

    1988-01-01

    A satellite-based mobile communications system provides voice and data communications to mobile users over a vast geographic area. The technical and service characteristics of mobile satellite systems (MSSs) are presented and form an in-depth view of the current MSS status at the system and subsystem levels. Major emphasis is placed on developments, current and future, in the following critical MSS technology areas: vehicle antennas, networking, modulation and coding, speech compression, channel characterization, space segment technology and MSS experiments. Also, the mobile satellite communications needs of government agencies are addressed, as is the MSS potential to fulfill them.

  9. Undergraduate Research Experiences in Support of Dryland Monitoring: Field and Satellite Remote Sensing of Change in Savanna Structure, Biomass, and Carbon after Prescribed Fires

    Science.gov (United States)

    Washington-Allen, R. A.; Twidwell, D. L., Jr.; Mendieta, V. P.; Delgado, A.; Redman, B.; Trollope, W. S.; Trollope, L.; Govender, N.; Smit, I.; Popescu, S. C.; de Bruno Austin, C.; Reeves, M. C.

    2009-12-01

    The status and trend of degradation in the world’s Drylands, that support over 1.2 billion people, is unknown because monitoring & assessment has not occurred on a globally consistent basis and skilled personnel with a cultivated interest in natural resource science and management are lacking. A major monitoring dataset is the 37-year Landsat data archive that has been released free to the world, but this dataset requires persons who understand how to process and interpret this and similar datasets applicable to the desertification problem. The College of Agriculture & Life Sciences (COALS) at Texas A&M University (TAMU) has an initiative to provide undergraduates with both international and research experiences. The lead author used start-up money, USFS project funds for livestock footprint studies in the US, and seed money from COALS to 1) develop academic mentor contacts in Mozambique, Namibia, Botswana, South Africa, and Tunisia to prepare a National Science Foundation Research Experience for Undergraduates (NSF-REU) Site proposal and 2) launch a pilot REU for two TAMU undergraduate students. Mr. Delgado and Mr. Redman received lidar processing and visualization, field survey training on global positioning systems (GPS), terrestrial LIDAR, and ground penetrating radar technologies and conducted carbon change studies by collecting pre- and post-fire laser scans on experimental burn (EPB) sites in Texas and South Africa. Mr. Redman also developed GIS databases of Landsat timeseries for these EPBs and others in southern Africa. Mr. Delgado participated in the Savanna Fire Ignition Research Experiment (SavFIRE) in Kruger National Park (KNP) by collected laser scan data on 3 EPBs. He also received mentoring from Dr. Winston Trollope, a prominent fire ecologist, and Mr. Chris Austin both of Working with Fire International and Navashni Govender, KNP’s Fire Ecologist. He also was an active participant in a NASA sponsored workshop on remote sensing of global

  10. The Simbox Experiment with Arabidopsis Thaliana Cell Cultures: Hardware-Tests and First Resutls from the German-Chinese satellite Mission Shenzhou 8

    Science.gov (United States)

    Fengler, Svenja; Neef, Maren; Ecke, Margret; Hampp, Ruediger

    2013-02-01

    The Simbox experiment was the first joint German-Chinese space project. In this context Arabidopsis thaliana cell cultures were exposed to microgravity for a 17-day period. To carry out a successful space mission, diverse hardware tests were performed in advance. Due to the limited oxygen supply inside the hardware units, cells were fixed after 5 days under microgravity conditions. As a control, samples were exposed in an on-board 1g reference centrifuge. To investigate the space effect, a ground-based study was performed with the same hardware and identical experimental procedures. As we were able to obtain high quality RNA from the RNAlater quenched samples, we used the Affymetrix Arabidopsis genome array for a transcriptome analysis. Our experiment aimed at the identification of plant genes that were differentially expressed after long-term exposure to microgravity. Pair-wise comparison of flight samples with 1g controls revealed the largest differences between space 1g and ground 1g controls.

  11. Age-Related Changes in Antioxidant and Glutathione S-Transferase Enzyme Activities in the Asian Clam.

    Science.gov (United States)

    Vranković, J

    2016-03-01

    Aging is accompanied by increased production of free oxygen radicals and impairment of normal cellular functions. The aim of this work was to provide preliminary data on age-related differences in the activities of antioxidant enzymes and phase II biotransformation enzyme glutathione S-transferase (GST) in a wild population of the Asian clam Corbicula fluminea. The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and GST were assessed in visceral mass of four age classes (0+-, 1+-, 2+-, and 3+-year-old) of C. fluminea clams. Age-related changes were seen in antioxidant enzyme status: levels of total SOD (totSOD) (P levels being the highest in age class II, then being lower in age classes III and IV (P enzyme activities, coupled with higher and lower activities of totSOD and CAT, respectively, as the individual grows older, may render the older animals more susceptible to oxidative stress. Data reported here are not intended to be exhaustive since they concern only age/size structure of the population at one locality, so more detailed studies on both the developmental stages and levels of antioxidant enzymes of this new alien species in Serbian rivers are required.

  12. Effects of LSP on micro-structures and residual stresses in a 4 mm CLAM steel weld joints

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xizhang, E-mail: chenxizhang@wzu.edu.cn [School of Mechanical and Electrical Engineering, Wenzhou University., Wenzhou 325035 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Fang, Yuanyuan [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Zhang, Shuyan; Kelleher, Joe F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Zhou, Jianzhong [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China)

    2015-05-15

    The effects of laser shock processing (LSP) on the distribution of residual stress and micro-structure of China Low Activation Martensitic (CLAM) steel weldment were investigated via neutron diffraction and optical microscope (OM). A pair of 4 mm CLAM steel plates joined by GTA welding. Special attention is paid to the generation of high level compressive residual stresses introduced by LSP. Residual stress in longitudinal, normal and transversal direction at weldment surface and longitudinal stress through thickness are evaluated via neutron diffraction. Compressive residual stress after LSP occurred at more than 90% areas within the weld joint, it is almost double the areas of compressive stress compare to weldment surface before LSP. The maximum compressive normal residual stress becomes to −183 MPa after LSP from −63 MPa before LSP. The Modification of surface micro-structures including weld zone (WZ), heat affected zone (HAZ) and base metal (BM) are also discussed. Results to date demonstrate that laser shock processing has been a great potential method for the improvement of mechanical performance of components.

  13. Cryptic species of deep-sea clams (Mollusca: Bivalvia: Vesicomyidae) from hydrothermal vent and cold-water seep environments

    Science.gov (United States)

    Vrijenhoek, Robert C.; Schutz, Steven J.; Gustafson, Richard G.; Lutz, Richard A.

    1994-08-01

    A protein-electrophoretic analysis of six putative morphospecies in the bivalve family Vesicomyidae from eight deep-sea hydrothermal vent sites in the eastern Pacific, three cold-water seep sites in the eastern Pacific and the Gulf of Mexico, and one whale-carcass site off Southern California revealed electromorph patterns diagnostic of 10 vesicomyid species. Electrophoretic patterns for 14 enzymes encoded by 17 presumptive gene loci were scored in all 10 species. The pairwise genetic distances (Nei's D) for these 10 species ranged from 0.857 to 2.792, values within the range expected for distinct species and genera. However, the degree of genetic divergence among these taxa could not be used for phylogenetic inferences because allozyme differences had in many cases reached evolutionary saturation. Notwithstanding, the present results revealed a significant problem with current morphospecies identifications of these clams and with applications of the current generic names Calyptogena and Vesicomya. Given the cryptic nature of these taxa, we suggest that subsequent studies simply refer to these clams as "vesicomyids" until careful morphological analyses and molecular studies are completed and systematic relationships are clarified.

  14. Development and validation of 89 novel expressed sequence tag-derived microsatellite markers in blood clam, Tegillarca granosa

    Science.gov (United States)

    Teng, Shuangshuang; Fang, Jun; Cai, Yilong; Chai, Xueliang; Xiao, Guoqiang

    2017-06-01

    Blood clam, Tegillarca granosa, is an important shellfish in Chinese mariculture industry. Investigative research in this species, such as genetic linkage mapping, requires a large panel of molecular markers. In present study, a total of 89 polymorphic microsatellite markers were developed in T. granosa using the sequence database of Life Sciences Technology 454 next generation sequencing technology. All 89 loci were characterized in 20 individual clams from a natural population inhabiting Yueqing Gulf, Zhejiang Province, China. The number of alleles per polymorphic locus varied between 2 and 15, while the observed heterozygosity, expected heterozygosity and polymorphic information content varied between 0.000 and 1.000, 0.102 and 0.921, and 0.048 and 0.886, respectively. Of the 89 loci identified, 32 loci deviated significantly from Hardy-Weinberg equilibrium following Bonferroni correction. Thirty nine markers, which were shown to be polymorphic in a full-sibling family, were tested in Mendelian segregations. As expected, 32 loci were co-dominantly segregated in a Mendelian fashion. These novel developed microsatellite markers represent useful research tools for investigation of population genetic structure and genetic diversity in this species.

  15. Cypermethrin-Induced Toxic Effect on Glycogen Metabolism in Estuarine Clam, Marcia Opima (Gmelin, 1791 of Ratnagiri Coast, Maharashtra

    Directory of Open Access Journals (Sweden)

    Medha Tendulkar

    2012-01-01

    Full Text Available Cypermethrin is a synthetic pyrethroid class of insecticide. Toxic effects of cypermethrin were studied by selecting Marcia opima as an animal model. Cypermethrins effect on the total glycogen content of mantle, gill, foot, hepatopancreas, male gonad and a female gonad of an estuarine clam, Marcia opima was examined. The clams were exposed to 1.58 ppm cypermethrin for acute and 1/th of that concentration for chronic treatment. It was found that there was a decrease in glycogen content in various tissues as compared to control. In LC0 and LC50 groups, glycogen was decreased in all tissues except in hepatopancreas compared to control. This decrease is greater in mantle, gill, and foot in LC50 group than the decrease in those tissues of LC0 group. In chronic exposure it was found that glycogen was decreased in mantle, foot, male gonad, and female gonad when compared to the control group except in gill and hepatopancreas. Decrease in glycogen content indicates greater utilization of glycogen for metabolic purposes and too combat with cypermethrin stress. The significant increase in glycogen content in gill and hepatopancreas may be a reaction to the increase in energy demand.

  16. Invasive zebra mussels (Driessena polymorpha) and Asian clams (Corbicula fluminea) survive gut passage of migratory fish species: implications for dispersal

    Science.gov (United States)

    Gatlin, Michael R.; Shoup, Daniel E.; Long, James M.

    2013-01-01

    The introduction and spread of invasive species is of great concern to natural resource managers in the United States. To effectively control the spread of these species, managers must be aware of the multitude of dispersal methods used by the organisms. We investigated the potential for survival through the gut of a migrating fish (blue catfish, Ictalurus furcatus) as a dispersal mechanism for two invasive bivalves: zebra mussel (Driessena polymorpha) and Asian clam (Corbicula fluminea). Blue catfish (N = 62) were sampled over several months from Sooner Lake, Oklahoma, transported to a laboratory and held in individual tanks for 48 h. All fecal material was collected and inspected for live mussels. Survival was significantly related to water temperature in the lake at the time of collection, with no mussels surviving above 21.1 C°, whereas 12 % of zebra mussels (N = 939) and 39 % of Asian clams (N = 408) consumed in cooler water survived gut passage. This research demonstrates the potential for blue catfish to serve as a dispersal vector for invasive bivalves at low water temperatures.

  17. Do you see what I see? Optical morphology and visual capability of ‘disco’ clams (Ctenoides ales

    Directory of Open Access Journals (Sweden)

    Lindsey F. Dougherty

    2017-05-01

    Full Text Available The ‘disco’ clam Ctenoides ales (Finlay, 1927 is a marine bivalve that has a unique, vivid flashing display that is a result of light scattering by silica nanospheres and rapid mantle movement. The eyes of C. ales were examined to determine their visual capabilities and whether the clams can see the flashing of conspecifics. Similar to the congener C. scaber, C. ales exhibits an off-response (shadow reflex and an on-response (light reflex. In field observations, a shadow caused a significant increase in flash rate from a mean of 3.9 Hz to 4.7 Hz (P=0.0016. In laboratory trials, a looming stimulus, which increased light intensity, caused a significant increase in flash rate from a median of 1.8 Hz to 2.2 Hz (P=0.0001. Morphological analysis of the eyes of C. ales revealed coarsely-packed photoreceptors lacking sophisticated structure, resulting in visual resolution that is likely too low to detect the flashing of conspecifics. As the eyes of C. ales are incapable of perceiving conspecific flashing, it is likely that their vision is instead used to detect predators.

  18. Chemical compositions and nutritional value of Asian hard clam (Meretrix lusoria) from the coast of Andaman Sea.

    Science.gov (United States)

    Karnjanapratum, Supatra; Benjakul, Soottawat; Kishimura, Hideki; Tsai, Yung-Hsiang

    2013-12-15

    Chemical compositions and nutritive value of the edible portions including foot, mantle and viscera of Asian hard clam (Meretrix lusoria) harvested from the coast of Andaman Sea were determined. Proximate compositions varied with portions tested. Edible portions had moisture (76.23-84.22%) and protein (9.09-12.75%) as the major components. Carbohydrate (0.32-7.89%), fat (1.58-6.58%) and ash (1.23-2.58%) were also found at various levels, dependent upon portions. Myofibrillar proteins were observed as the major fraction in foot (40.54%) and mantle (31.65%), whilst non-protein nitrogen constituents were dominant in the viscera (36.85%). All portions contained a large amount of essential amino acids (167.66-187.63 mg/g sample), in which leucine (30.91-36.96 mg/g sample) and lysine (35.24-36.03 mg/g sample) were predominant. They were rich in polyunsaturated fatty acids (46.84-49.18% of total fatty acid) with high level of DHA (13.33-16.47 % of total fatty acids) and EPA (4.75-7.11% of total fatty acids). Cholesterol of 0.07-0.21% wet weight was detected. All portions were also rich in macro- (Na, K, Ca and Mg) and micro- (Fe, Zn, Cu and Cr) minerals. Therefore, Asian hard clam is an excellent source of several nutrients, which could be beneficial for the health of the consumers.

  19. Commercial Manila clam ( Tapes philippinarum) culture in British Columbia, Canada: The effects of predator netting on intertidal sediment characteristics

    Science.gov (United States)

    Munroe, Daphne; McKinley, R. Scott

    2007-03-01

    Quantifying risks posed by aquaculture to adjacent coastal ecosystems is necessary to ensure long term stability of coastal systems and the sustainability of industries that exist therein. Research has demonstrated that the use of predator netting in shellfish aquaculture increases sedimentation rates and productivity; here we examine the influence of netting on the west coast of Canada. Changes in percent silt (sediment particles gravel (sediment particles >2 mm), organic and inorganic carbon levels and temperature, and differences in clam populations were monitored on paired netted and non-netted Manila clam ( Tapes philippinarum) plots on four farmed beaches at Baynes Sound, British Columbia in 2003 and 2004. There were no significant differences in the levels of silt ( p = 0.129, n = 8), gravel ( p = 0.723, n = 8), or inorganic carbon ( p = 0.070, n = 8) between netted and non-netted plots. However, the level of organic carbon was significantly higher on netted plots ( p = 0.014, n = 8) and a slight temperature buffering effect of the netting during low-tide events over the period of study. There were significantly more T. philippinarum on netted plots compared to non-netted plots ( p = 0.001, n = 8) and the length frequency distribution of the populations also differed ( p Sound British Columbia, has limited effect on the sediment.

  20. Histopathological survey of the mussel Mytilus chilensis (Mytilidae and the clam Gari solida (Psammobiidae from southern Chile

    Directory of Open Access Journals (Sweden)

    Florencia Cremonte

    2015-03-01

    Full Text Available A total of 175 specimens of mussels, Mytilus chilensis (Mytilidae, and 56 specimens of clams, Gari solida (Psammobiidae, were collected in natural beds and culture sites of southern Chile. Juvenile mussel specimens (3 cm of maximum length were free of parasites and diseases, whilst the commercial sized populations was parasitized by intracellular inclusions of bacteria-like organisms in the digestive gland epithelium and in the gills, by ciliates in the gills, turbellarians similar to Paravortex (Rhabocoela in the intestine lumen and copepods attached to the gills. In addition, the disseminated neoplasia disease was also present although in low prevalences. In the clam, G. solida, prokariotic inclusions were found in the digestive gland epithelium and bacteria-like organisms in the gills, often encapsulated by haemocytes; oocysts containing up to 8 sporozoites similar to Nematopsis (Apicomplexa in the connective tissue, causing haemocytic infiltration when the intensity of infection was high; ciliates belonging to two different species (one of them similar to Trichodina inhabiting the gills; and a turbellarian similar to Paravortex in the lumen of digestive system without apparent host reaction. The populations of the bivalve species here studied were devoid of serious pathogens.

  1. The influence of salinity on toxicological effects of arsenic in digestive gland of clam Ruditapes philippinarum using metabolomics

    Institute of Scientific and Technical Information of China (English)

    JI Chenglong; WU Huifeng; LIU Xiaoli; ZHAO Jianmin; YU Junbao; YIN Xiuli

    2013-01-01

    Ruditapes philippinarum,a clam that thrives in intertidal zones of various salinities,is a useful biomonitor to marine contaminants.We investigated the influence of dilution to 75% and 50% of normal seawater salinity (31.1) on the responses of the digestive gland of R.philippinarum to arsenic exposure (20 μg/L),using nuclear magnetic resonance (NMR)-based metabolomics.After acute arsenic exposure for 48 h,salinity-dependent differential metabolic responses were detected.In normal seawater,arsenic exposure increased the concentrations of branched-chain amino acids,and of threonine,proline,phosphocholine and adenosine,and it decreased the levels of alanine,hypotaurine,glucose,glycogen and ATP in the digestive glands.Differential changes in metabolic biomarkers observed at lower salinity (~23.3)included elevation of succinate,taurine and ATP,and depletion of branched-chain amino acids,threonine and glutamine.Unique effects of arsenic at the lowest salinity (~15.6) included down-regulation of glutamate,succinate and ADP,and up-regulation of phosphocholine.We conclude that salinity influences the metabolic responses of this clam to arsenic.

  2. Identification of a regulation network in response to cadmium toxicity using blood clam Tegillarca granosa as model

    Science.gov (United States)

    Bao, Yongbo; Liu, Xiao; Zhang, Weiwei; Cao, Jianping; Li, Wei; Li, Chenghua; Lin, Zhihua

    2016-01-01

    Clam, a filter-feeding lamellibranch mollusk, is capable to accumulate high levels of trace metals and has therefore become a model for investigation the mechanism of heavy metal toxification. In this study, the effects of cadmium were characterized in the gills of Tegillarca granosa during a 96-hour exposure course using integrated metabolomic and proteomic approaches. Neurotoxicity and disturbances in energy metabolism were implicated according to the metabolic responses after Cd exposure, and eventually affected the osmotic function of gill tissue. Proteomic analysis showed that oxidative stress, calcium-binding and sulfur-compound metabolism proteins were key factors responding to Cd challenge. A knowledge-based network regulation model was constructed with both metabolic and proteomic data. The model suggests that Cd stimulation mainly inhibits a core regulation network that is associated with histone function, ribosome processing and tight junctions, with the hub proteins actin, gamma 1 and Calmodulin 1. Moreover, myosin complex inhibition causes abnormal tight junctions and is linked to the irregular synthesis of amino acids. For the first time, this study provides insight into the proteomic and metabolomic changes caused by Cd in the blood clam T. granosa and suggests a potential toxicological pathway for Cd. PMID:27760991

  3. Identification of Perkinsus-like parasite in Manila clam, Ruditapes philippinarum using DNA molecular marker at ITS region

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Genomic DNA was extracted from hypnospores of Perkinsus-like parasite of Manila clam Ruditapes philippinarum collected at the fishing grounds in Huanghai Sea coast Shicheng Island and East China Sea coast Ningbo, China. The internal transcribed spacer(ITS)in rDNA was PCR-amplified, cloned, sequenced, and compared with that of five Perkinsus species in GenBank. The fragment amplified from DNA of parasite of either Shicheng Island or Ningbo contained 649 bp, including partial ssrRNA(51 bp) and ITS(+5.8 S)(598 bp) regions. The ITS(+5.8S) sequences of Perkinsus-like parasite of both Shicheng Island and Ningbo were all 99% identical to those ofPerkinsus atlanticus,and were not more than 95% identical to those of other four Perkinsus species including P. marinus, P.andrewsi, P. qugwadi and P. medierraneus.The ITS (+5.8S) sequence of Perkinsus-like parasite of Shicheng Island was 99% identical to that of Ningbo. These facts about nucleotide sequences suggested that the Perkinsus-like parasite in Manila clam, Ruditapes philippinarum collected from either the Huanghai Sea coast or the East China Sea coast was P. atlanticus, and might reflect P. atlanticus strains of distinct geographic distribution.

  4. Identification of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Enzymatic Hydrolysates of Razor Clam Sinonovacula constricta

    Directory of Open Access Journals (Sweden)

    Yun Li

    2016-06-01

    Full Text Available Angiotensin I-converting enzyme (ACE inhibitory activity of razor clam hydrolysates produced using five proteases, namely, pepsin, trypsin, alcalase, flavourzyme and proteases from Actinomucor elegans T3 was investigated. Flavourzyme hydrolysate showed the highest level of degree of hydrolysis (DH (45.87% followed by A. elegans T3 proteases hydrolysate (37.84% and alcalase (30.55%. The A. elegans T3 proteases was observed to be more effective in generating small peptides with ACE-inhibitory activity. The 3 kDa membrane permeate of A. elegans T3 proteases hydrolysate showed the highest ACE-inhibitory activity with an IC50 of 0.79 mg/mL. After chromatographic separation by Sephadex G-15 gel filtration and reverse phase-high performance liquid chromatography, the potent fraction was subjected to MALDI/TOF-TOF MS/MS for identification. A novel ACE-inhibitory peptide (VQY was identified exhibiting an IC50 of 9.8 μM. The inhibitory kinetics investigation by Lineweaver-Burk plots demonstrated that the peptide acts as a competitive ACE inhibitor. The razor clam hydrolysate obtained by A. elegans T3 proteases could serve as a source of functional peptides with ACE-inhibitory activity for physiological benefits.

  5. Growth Performance of Larval and Juvenile Manila Clam (Ruditapes philippinarum) from Divergently Selected Individuals of a Full-Sib Family

    Institute of Scientific and Technical Information of China (English)

    HUO Zhongming; LI Xiaotong; SUN Qian; LI Yongren; ZHANG Xuekai; YAN Xiwu; YANG Feng

    2016-01-01

    In this study, the method of divergent selection was employed to test the larval and juvenile growth performance within a full-sib family of Manila clamRuditapes philippinarum. The 10% largest and 10% smallest clam individuals (on the basis of shell length) of a full-sib family were selected as parents for the fast and slow growing lines, respectively. The difference in shell length was significant among the three lines (fast, control, and slow) tested. The sequence of shell length were fast line>control line>slow line. The responses to selection, realized heritability, and genetic gain were 0.06%–0.81%, 0.04%–0.47% and 0.58%–18.89% in the fast direction, respectively; and were 0.14%–1.27%, 0.08%–0.73%, and 0.31%–49.03% in the slow direction, respectively. The re-sults suggested that there was a large portion of additive genetic variance affecting the growth in the full-sib family. Selection in the fast direction within the full-sib family would greatly improve the growth ofR. philippinarum.

  6. Removal of methyl orange and methylene blue dyes from aqueous solution using lala clam (Orbicularia orbiculata) shell

    Science.gov (United States)

    Eljiedi, Arwa Alseddig Ahmed; Kamari, Azlan

    2017-05-01

    Textile effluents are considered as potential sources of water pollution because they contain toxic dyes. In the present study, lala clam shell was used as an alternative low-cost adsorbent for the removal of two harmful dyes, namely methyl orange (MO) and methylene blue (MB) from aqueous solution. Batch adsorption studies were carried out by varying experimental parameters such as solution pH, initial concentration and adsorbent dosage. The optimum pH values for MO and MB removal were pH 2.0 and pH 8.0, respectively. At an initial MO and MB concentration of 20 mg/L, the maximum removal percentage of MO and MB were 18.9 % and 81.3 %, respectively. The adsorption equilibrium data were correlated with both Langmuir and Freundlich isotherm models. The biomass adsorbent was characterised using Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared Spectrometer (FTIR). Results from this study suggest that lala clam shell, a fishery waste, can be beneficial for water treatment.

  7. Trends in NASA communication satellites.

    Science.gov (United States)

    Sivo, J. N.; Robbins, W. H.; Stretchberry, D. M.

    1972-01-01

    Discussion of the potential applications of satellite communications technology in meeting the national needs in education, health care, culture, and data transfer techniques. Experiments with the NASA ATS 1, 3 and 5 spacecraft, which are conducted in an attempt to satisfy such needs, are reviewed. The future needs are also considered, covering the requirements of multiple region coverage, communications between regions, large numbers of ground terminals, multichannel capability and high quality TV pictures. The ATS F and CTS spacecraft are expected to be available in the near future to expand experiments in this field.

  8. Tropomyosin and Actin Identified as Major Allergens of the Carpet Clam (Paphia textile and the Effect of Cooking on Their Allergenicity

    Directory of Open Access Journals (Sweden)

    Zailatul Hani Mohamad Yadzir

    2015-01-01

    Full Text Available Objectives. To identify the major allergenic proteins of clam (Paphia textile and to investigate the effect of different cooking methods on the allergenicity of these identified proteins. Methods. Clam protein extracts were separated by denaturing polyacrylamide gel electrophoresis. IgE reactive proteins were then analyzed by immunoblotting with sera from patients with positive skin prick tests (SPT to the raw clam extract. Mass spectrometry was used to identify the major allergenic proteins of this clam. Results. Raw extract showed 12 protein bands (18–150 kDa. In contrast, fewer protein bands were seen in the boiled extract; those ranging from 40 to 150 kDa were denatured. The protein profiles were similarly altered by frying or roasting. The immunoblots of raw and boiled extracts yielded 10 and 2 IgE-binding proteins, respectively. The fried and roasted extracts showed only a single IgE-binding protein at 37 kDa. Mass spectrometry analysis of the 37 and 42 kDa major allergens indicated that these spots were tropomyosin and actin, respectively. Conclusion. The two major allergens of Paphia textile were identified as the thermostable tropomyosin and a new thermolabile allergen actin.

  9. Molecular cloning, characterization, and expression analysis of a gonadotropin-releasing hormone-like cDNA in the clam, Ruditapes philippinarum.

    Science.gov (United States)

    Song, Ying; Miao, Jingjing; Cai, Yuefeng; Pan, Luqing

    2015-11-01

    Gonadotropin-releasing hormone (GnRH) is a key neuropeptide regulating reproduction in vertebrates. In the present study, we have cloned and identified the cDNA sequence of the prepro-GnRH (rp-GnRH) in the Manila clam Ruditapes philippinarum. The open reading frame encodes a protein of 94 amino acids, which consists of a signal peptide, a GnRH dodecapeptide, a cleavage site, and a GnRH-associated peptide. These deduced peptides were highly homologous to that reported for other molluscs. We used temperature control to promote gonadal development of the clams. The mRNA expression of rp-GnRH in the visceral ganglia from clams at different reproductive stages was determined by quantitative RT-PCR. The levels of steroids progesterone (P), testosterone (T), and estradiol-17β (E2) in the hemolymph of the corresponding clam were measured by ELISA. The rp-GnRH mRNA was highly expressed at the gonadal early development stage. Concentrations of P, T, and E2 also increased at the early development stage in both sexes. Positive significant correlations between rp-GnRH expression and P content as well as between rp-GnRH expression and T content were observed throughout the gonadal maturation. The results from this study may help to better understand the physiological functions of the native forms of GnRH-like peptides and the actions of GnRH on sex steroids release in bivalve molluscs.

  10. Perkinsus olseni and P. chesapeaki detected in a survey of perkinsosis of various clam species in Galicia (NW Spain) using PCR-DGGE as a screening tool.

    Science.gov (United States)

    Ramilo, Andrea; Pintado, José; Villalba, Antonio; Abollo, Elvira

    2016-01-01

    A survey on perkinsosis was performed involving 15 locations scattered along the Galician coast (NW Spain) and four clam species with high market value (Ruditapes decussatus, Ruditapes philippinarum, Venerupis corrugata and Polititapes rhomboides). The prevalence of Perkinsus parasites was estimated by PCR using genus-specific primers. The highest percentage of PCR-positive cases for perkinsosis corresponded to clams R. decussatus and V. corrugata, while lower values were detected in R. philippinarum and no case was found in P. rhomboides. The discrimination of Perkinsus species was performed by PCR-RFLP and by a new PCR-DGGE method developed in this study. Perkinsus olseni was identified in every clam species, except in P. rhomboides, using both PCR-DGGE and PCR-RFLP. Additionally, Perkinsus chesapeaki was only detected by PCR-DGGE infecting two Manila clams R. philippinarum from the same location, reporting the first case in Galicia. P. chesapeaki identification was further confirmed by in situ hybridisation assay and phylogenetic analysis of ITS region and LSU rDNA.

  11. Molecular and histological identification of Marteilioides infection in Suminoe Oyster Crassostrea ariakensis, Manila Clam Ruditapes philippinarum and Pacific Oyster Crassostrea gigas on the south coast of Korea.

    Science.gov (United States)

    Limpanont, Yanin; Yanin, Limpanont; Kang, Hyun-Sil; Hong, Hyun-Ki; Jeung, Hee-Do; Kim, Bong-Kyu; Le, Thanh Cuong; Kim, Young-Ok; Choi, Kwang-Sik

    2013-11-01

    The oyster ovarian parasite Marteilioides chungmuensis has been reported from Korea and Japan, damaging the oyster industries. Recently, Marteilioides-like organisms have been identified in other commercially important marine bivalves. In this study, we surveyed Marteilioides infection in the Manila clam Ruditapes philippinarum, Suminoe oyster Crassostrea ariakensis, and Pacific oyster Crassostrea gigas, using histology and Marteilioides-specific small subunit (SSU) rDNA PCR. The SSU rDNA sequence of M. chungmuensis (1716 bp) isolated from C. gigas in Tongyoung bay was 99.9% similar to that of M. chungmuensis reported in Japan. Inclusions of multi-nucleated bodies in the oocytes, typical of Marteilioides infection, were identified for the first time in Suminoe oysters. The SSU rDNA sequence of a Marteilioides-like organism isolated from Suminoe oysters was 99.9% similar to that of M. chungmuensis. Marteilioides sp. was also observed from 7 Manila clams of 1840 individuals examined, and the DNA sequences of which were 98.2% similar to the known sequence of M. chungmuensis. Unlike Marteilioides infection of Pacific oysters, no remarkable pathological symptoms, such as large multiple lumps on the mantle, were observed in infected Suminoe oysters or Manila clams. Distribution of the infected Manila clams, Suminoe oysters and Pacific oysters was limited to small bays on the south coast, suggesting that the southern coast is the enzootic area of Marteilioides infection.

  12. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  13. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  14. Methods of satellite oceanography

    Science.gov (United States)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  15. AMOS Galaxy 15 Satellite Observations and Analysis

    Science.gov (United States)

    Hall, D.

    2011-09-01

    In early April 2010, the Galaxy 15 geosynchronous satellite experienced an on-orbit anomaly. Even though the satellite's transmitters and articulating solar panel were still functioning, ground controllers lost the ability to command and maneuver the satellite. With its orbital position no longer maintained, Galaxy 15 began to drift eastward. This forced several other satellites to make collision avoidance maneuvers during the following months. Soon after the initial anomaly, Galaxy 15's operators predicted that the satellite’s reaction wheels would eventually become saturated, causing a loss of both spacecraft attitude and proper sunward orientation of the solar panels. This "off-pointing" event finally occurred in late December, ultimately leading to a depletion of Galaxy 15's batteries. This near-death experience had a fortunate side effect, however, in that it forced the satellite’s command unit to reboot and once again be able to both receive and execute ground commands. The satellite operators have since recovered control of the satellite. AMOS conducted non-resolved photometric observations of Galaxy 15 before, during and after these events. Similar observations were conducted of Galaxy 12, the nearly-identical replacement satellite. This presentation presents and discusses these temporal brightness signatures in detail, comparing the changing patterns in the observations to the known sequence of events.

  16. Satellite-Based Quantum Communications

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard J [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; McCabe, Kevin P [Los Alamos National Laboratory; Newell, Raymond T [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory

    2010-09-20

    Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

  17. Characterisation of 12 microsatellite loci in the Vietnamese commercial clam Lutraria rhynchaena Jonas 1844 (Heterodonta: Bivalvia: Mactridae) through next-generation sequencing.

    Science.gov (United States)

    Thai, Binh Thanh; Tan, Mun Hua; Lee, Yin Peng; Gan, Han Ming; Tran, Trang Thi; Austin, Christopher M

    2016-05-01

    The marine clam Lutraria rhynchaena is gaining popularity as an aquaculture species in Asia. Lutraria populations are present in the wild throughout Vietnam and several stocks have been established and translocated for breeding and aquaculture grow-out purposes. In this study, we demonstrate the feasibility of utilising Illumina next-generation sequencing technology to streamline the identification and genotyping of microsatellite loci from this clam species. Based on an initial partial genome scan, 48 microsatellite markers with similar melting temperatures were identified and characterised. The 12 most suitable polymorphic loci were then genotyped using 51 individuals from a population in Quang Ninh Province, North Vietnam. Genetic variation was low (mean number of alleles per locus = 2.6; mean expected heterozygosity = 0.41). Two loci showed significant deviation from Hardy-Weinberg equilibrium (HWE) and the presence of null alleles, but there was no evidence of linkage disequilibrium among loci. Three additional populations were screened (n = 7-36) to test the geographic utility of the 12 loci, which revealed 100 % successful genotyping in two populations from central Vietnam (Nha Trang). However, a second population from north Vietnam (Co To) could not be successfully genotyped and morphological evidence and mitochondrial variation suggests that this population represents a cryptic species of Lutraria. Comparisons of the Qang Ninh and Nha Trang populations, excluding the 2 loci out of HWE, revealed statistically significant allelic variation at 4 loci. We reported the first microsatellite loci set for the marine clam Lutraria rhynchaena and demonstrated its potential in differentiating clam populations. Additionally, a cryptic species population of Lutraria rhynchaena was identified during initial loci development, underscoring the overlooked diversity of marine clam species in Vietnam and the need to genetically characterise population representatives prior

  18. Interactive effects of mosquito control insecticide toxicity, hypoxia, and increased carbon dioxide on larval and juvenile eastern oysters and hard clams.

    Science.gov (United States)

    Garcia, R N; Chung, K W; Key, P B; Burnett, L E; Coen, L D; Delorenzo, M E

    2014-04-01

    Mosquito control insecticide use in the coastal zone coincides with the habitat and mariculture operations of commercially and ecologically important shellfish species. Few data are available regarding insecticide toxicity to shellfish early life stages, and potential interactions with abiotic stressors, such as low oxygen and increased CO2 (low pH), are less understood. Toxicity was assessed at 4 and 21 days for larval and juvenile stages of the Eastern oyster, Crassostrea virginica, and the hard clam, Mercenaria mercenaria, using two pyrethroids (resmethrin and permethrin), an organophosphate (naled), and a juvenile growth hormone mimic (methoprene). Acute toxicity (4-day LC50) values ranged from 1.59 to >10 mg/L. Overall, clams were more susceptible to mosquito control insecticides than oysters. Naled was the most toxic compound in oyster larvae, whereas resmethrin was the most toxic compound in clam larvae. Mortality for both species generally increased with chronic insecticide exposure (21-day LC50 values ranged from 0.60 to 9.49 mg/L). Insecticide exposure also caused sublethal effects, including decreased swimming activity after 4 days in larval oysters (4-day EC50 values of 0.60 to 2.33 mg/L) and decreased growth (shell area and weight) in juvenile clams and oysters after 21 days (detected at concentrations ranging from 0.625 to 10 mg/L). Hypoxia, hypercapnia, and a combination of hypoxia and hypercapnia caused mortality in larval clams and increased resmethrin toxicity. These data will benefit both shellfish mariculture operations and environmental resource agencies as they manage the use of mosquito control insecticides near coastal ecosystems.

  19. Contrasting Physiological Responses of Two Populations of the Razor Clam Tagelus dombeii with Different Histories of Exposure to Paralytic Shellfish Poisoning (PSP)

    Science.gov (United States)

    Navarro, Jorge M.; González, Katerina; Cisternas, Barbara; López, Jorge A.; Chaparro, Oscar R.; Segura, Cristian J.; Córdova, Marco; Suárez-Isla, Benjamín; Fernandez-Reiriz, María J.; Labarta, Uxio

    2014-01-01

    This study describes the physiological performance of two populations of the razor clam Tagelus dombeii from two geographic areas with different histories of exposure to paralytic shellfish poisoning (PSP) linked to the toxic dinoflagellate Alexandrium catenella. Clams from Melinka-Aysén, which are frequently exposed to PSP, were not affected by the presence of toxins in the diet. However, clams from Corral-Valdivia, which have never been exposed to PSP, exhibited significantly reduced filtration activity and absorption, affecting the energy allocated to scope for growth (SFG). Ammonia excretion and oxygen uptake were not affected significantly by the presence of A. catenella in the diet. Measurements of energy acquisition and expenditure were performed during a 12-day intoxication period. According to three-way repeated measure ANOVAs, the origin of the clams had a highly significant effect on all physiological variables, and the interaction between diet and origin was significant for the clearance and absorption rates and for the scope for growth. The scope for growth index showed similar positive values for both the toxic and non-toxic individuals from the Melinka-Aysén population. However, it was significantly reduced in individuals from Corral-Valdivia when exposed to the diet containing A. catenella. The absence of differences between the physiological response of the toxic and non-toxic clams from Melinka-Aysén may be related to the frequent presence of A. catenella in the environment, indicating that this bivalve does not suffer negative consequences from PSP. By contrast, A. catenella has a negative effect on the physiological performance, primarily on the energy gained from the environment, on T. dombeii from Corral-Valdivia. This study supports the hypothesis that the history of PSP exposure plays an important role in the physiological performance and fitness of filter feeding bivalves. PMID:25153329

  20. Contrasting physiological responses of two populations of the razor clam Tagelus dombeii with different histories of exposure to paralytic shellfish poisoning (PSP).

    Science.gov (United States)

    Navarro, Jorge M; González, Katerina; Cisternas, Barbara; López, Jorge A; Chaparro, Oscar R; Segura, Cristian J; Córdova, Marco; Suárez-Isla, Benjamín; Fernandez-Reiriz, María J; Labarta, Uxio

    2014-01-01

    This study describes the physiological performance of two populations of the razor clam Tagelus dombeii from two geographic areas with different histories of exposure to paralytic shellfish poisoning (PSP) linked to the toxic dinoflagellate Alexandrium catenella. Clams from Melinka-Aysén, which are frequently exposed to PSP, were not affected by the presence of toxins in the diet. However, clams from Corral-Valdivia, which have never been exposed to PSP, exhibited significantly reduced filtration activity and absorption, affecting the energy allocated to scope for growth (SFG). Ammonia excretion and oxygen uptake were not affected significantly by the presence of A. catenella in the diet. Measurements of energy acquisition and expenditure were performed during a 12-day intoxication period. According to three-way repeated measure ANOVAs, the origin of the clams had a highly significant effect on all physiological variables, and the interaction between diet and origin was significant for the clearance and absorption rates and for the scope for growth. The scope for growth index showed similar positive values for both the toxic and non-toxic individuals from the Melinka-Aysén population. However, it was significantly reduced in individuals from Corral-Valdivia when exposed to the diet containing A. catenella. The absence of differences between the physiological response of the toxic and non-toxic clams from Melinka-Aysén may be related to the frequent presence of A. catenella in the environment, indicating that this bivalve does not suffer negative consequences from PSP. By contrast, A. catenella has a negative effect on the physiological performance, primarily on the energy gained from the environment, on T. dombeii from Corral-Valdivia. This study supports the hypothesis that the history of PSP exposure plays an important role in the physiological performance and fitness of filter feeding bivalves.

  1. The Principle of Navigation Constellation Composed of SIGSO Communication Satellites

    CERN Document Server

    Ji, Hai-Fu; Ai, Guo-Xiang; Shi, Hu-Li

    2012-01-01

    The Chinese Area Positioning System (CAPS), a navigation system based on GEO communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioning experiments of CAPS have been performed since 2005. On the basis of CAPS, this paper studies the principle of navigation constellation composed of Slightly Inclined Geostationary Orbit (SIGSO) communication satellites. SIGSO satellites are derived from end-of-life Geostationary Orbit (GEO) satellites under inclined orbit operation. Considering the abundant frequency resources of SIGSO satellites, multi-frequency observations could be conducted to enhance the precision of pseudorange measurements and ameliorate the positioning performence. The constellation composed of two GEO satellites and four SIGSO satellites with inclination of 5 degrees can provide the most territory of China with 24-hour maximum PDOP less than 42. With synthetic utilization of the truncated precise (TP) code and physical augmentation factor in fo...

  2. Satellite Meteorology Education & Training Resources from COMET

    Science.gov (United States)

    Abshire, W. E.; Dills, P. N.; Weingroff, M.; Lee, T. F.

    2012-12-01

    The COMET® Program (www.comet.ucar.edu) receives funding from NOAA NESDIS as well as EUMETSAT and the Meteorological Service of Canada to support education and training in satellite meteorology. These partnerships enable COMET to create educational materials of global interest on geostationary and polar-orbiting remote sensing platforms. These materials focus on the capabilities and applications of current and next-generation satellites and their relevance to operational forecasters and other user communities. By partnering with experts from the Naval Research Laboratory, NOAA-NESDIS and its Cooperative Institutes, Meteorological Service of Canada, EUMETSAT, and other user communities, COMET stimulates greater use of satellite data observations and products. This presentation provides an overview of COMET's recent satellite education efforts in the area of polar orbiting satellites. COMET has a new module on Suomi NPP, which describes the satellite system and discusses the improvements that it is bringing to forecasting, numerical weather prediction, and environmental monitoring. COMET has also published an updated version of its module on the VIIRS instrument. "Imaging with VIIRS: A Convergence of Technologies and Experience, 2nd Edition" covers the instrument's enhanced capabilities by examining the systems that contributed to its development. Special attention is paid to the Day/Night Visible channel as VIIRS is the first instrument on a civilian satellite to image atmospheric and terrestrial features with and without moonlight. An upcoming module will exclusively focus on nighttime imaging with the VIIRS Day/Night Band (DNB). "Applications of the VIIRS Day-Night Band" will introduce the capabilities of DNB imagery to a wide audience ranging from forecasters and emergency managers to wildfire fighters and oceanographers. DNB products will be compared to traditional satellite products made from infrared data, including the "fog" product. Users will learn how DNB

  3. Satellite SAR imagery for site discovery, change detection and monitoring activities in cultural heritage sites: experiments on the Nasca region, Peru

    Science.gov (United States)

    Tapete, D.; Cigna, F.; Masini, N.; Lasaponara, R.

    2012-04-01

    Besides their suitability for multi-temporal and spatial deformation analysis, the Synthetic Aperture Radar (SAR) image archives acquired by space-borne radar sensors can be exploited to support archaeological investigations over huge sites, even those partially or totally buried and still to be excavated. Amplitude information is one of the main properties of SAR data from which it is possible to retrieve evidences of buried structures, using feature extraction and texture analysis. Multi-temporality allows the reconstruction of past and recent evolution of both landscape and built-up environment, with the possibility to detect natural and/or anthropogenic changes, including human-induced damages to the conservation of cultural heritage. We present the methodology and first results of the experiments currently undertaken using SAR data in the Nasca region (Southern Peru), where two important civilizations such as Paracas and Nasca developed and flourished from 4th century BC to the 6th century AD. The study areas include a wide spectrum of archaeological and environmental elements to be preserved, among which: the archaeological site of Cahuachi and its surroundings, considered the largest adobe Ceremonial Centre in the World; the Nasca lines and geoglyphs in the areas of Palpa, Atarco and Nasca; the ancient networks of aqueducts and drainage galleries in the Puquios area, built by Nasca in the 1st-6th centuries AD. Archaeological prospection and multi-purpose remote sensing activities are currently carried out in the framework of the Italian mission of heritage Conservation and Archaeogeophysics (ITACA), with the direct involvement of researchers from the Institute for Archaeological and Monumental Heritage and the Institute of Methodologies for Environmental Analysis, Italian National Research Council. In this context, C- and L-band SAR images covering the Nasca region since 2001 were identified for the purposes of this research and, in particular, the following

  4. Design of a Representative Low Earth Orbit Satellite to Improve Existing Debris Models

    Science.gov (United States)

    Clark, S.; Dietrich, A.; Werremeyer, M.; Fitz-Coy, N.; Liou, J.-C.

    2012-01-01

    This paper summarizes the process and methodologies used in the design of a small-satellite, DebriSat, that represents materials and construction methods used in modern day Low Earth Orbit (LEO) satellites. This satellite will be used in a future hypervelocity impact test with the overall purpose to investigate the physical characteristics of modern LEO satellites after an on-orbit collision. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was conducted in 1992. The target used for that experiment was a Navy Transit satellite (40 cm, 35 kg) fabricated in the 1960 s. Modern satellites are very different in materials and construction techniques from a satellite built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. The design of DebriSat will focus on designing and building a next-generation satellite to more accurately portray modern satellites. The design of DebriSat included a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 10 kg to 5000 kg. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions, and helped direct the design of DebriSat.

  5. Satellites of spiral galaxies

    Science.gov (United States)

    Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

    1993-01-01

    We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

  6. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  7. Improvement of orbit determination accuracy for Beidou Navigation Satellite System with Two-way Satellite Time Frequency Transfer

    Science.gov (United States)

    Tang, Chengpan; Hu, Xiaogong; Zhou, Shanshi; Guo, Rui; He, Feng; Liu, Li; Zhu, Lingfeng; Li, Xiaojie; Wu, Shan; Zhao, Gang; Yu, Yang; Cao, Yueling

    2016-10-01

    The Beidou Navigation Satellite System (BDS) manages to estimate simultaneously the orbits and clock offsets of navigation satellites, using code and carrier phase measurements of a regional network within China. The satellite clock offsets are also directly measured with Two-way Satellite Time Frequency Transfer (TWSTFT). Satellite laser ranging (SLR) residuals and comparisons with the precise ephemeris indicate that the radial error of GEO satellites is much larger than that of IGSO and MEO satellites and that the BDS orbit accuracy is worse than GPS. In order to improve the orbit determination accuracy for BDS, a new orbit determination strategy is proposed, in which the satellite clock measurements from TWSTFT are fixed as known values, and only the orbits of the satellites are solved. However, a constant systematic error at the nanosecond level can be found in the clock measurements, which is obtained and then corrected by differencing the clock measurements and the clock estimates from orbit determination. The effectiveness of the new strategy is verified by a GPS regional network orbit determination experiment. With the IGS final clock products fixed, the orbit determination and prediction accuracy for GPS satellites improve by more than 50% and the 12-h prediction User Range Error (URE) is better than 0.12 m. By processing a 25-day of measurement from the BDS regional network, an optimal strategy for the satellite-clock-fixed orbit determination is identified. User Equivalent Ranging Error is reduced by 27.6% for GEO satellites, but no apparent reduction is found for IGSO/MEO satellites. The SLR residuals exhibit reductions by 59% and 32% for IGSO satellites but no reductions for GEO and MEO satellites.

  8. Metabolic responses of clams, Ruditapes decussatus and Ruditapes philippinarum, to short-term exposure to lead and zinc.

    Science.gov (United States)

    Aru, Violetta; Sarais, Giorgia; Savorani, Francesco; Engelsen, Søren Balling; Cesare Marincola, Flaminia

    2016-06-15

    This study investigated the effects of 48h heavy metal exposure upon the metabolic profiles of Ruditapes decussatus and Ruditapes philippinarum using (1)H NMR metabolomics. Both species were exposed to increasing concentrations of lead nitrate (10, 40, 60 and 100μg/L) and zinc chloride (20, 50, 100 and 150μg/L), under laboratory conditions. ICP-OES analysis was further performed on the clams' samples in order to verify the occurrence of heavy metal bioaccumulation. With respect to the controls, the metabolic profiles of treated R. decussatus exhibited higher levels of organic osmolytes and lower contents of free amino acids. An opposite behavior was shown by R. philippinarum. In terms of heavy metal, the exposure effects were more evident in the case of Pb rather than Zn. These findings show that NMR-based metabolomics has the required sensitivity and specificity for the identification of metabolites that can act as sensitive indicators of contaminant-induced stress.

  9. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  10. Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qing [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Zhang, Yong [Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China); Peng, Hui-Fang [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); Ke, Cai-Huan, E-mail: chke@xmu.edu.cn [State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Huang, He-Qing, E-mail: hqhuang@xmu.edu.cn [State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen 361102 (China); State Key Laboratory of Marine Environmental Science, School of Ocean and Earth Science, Xiamen University, Xiamen 361102 (China); Department of Chemistry, College of Chemistry and Chemical Engineering, and the Key Laboratory of Chemical Biology of Fujian Province, Xiamen University, Xiamen 361102 (China)

    2014-11-15

    Highlights: • Fe accumulated in hepatopancreas tissues after iron-enriched exposure. • Ferritin expression was positively correlated with iron concentration in seawater. • Ferritin appears to be involved in iron homeostasis and immune defense mechanism of M. meretrix. • mRNAs of cytokine genes responded faster than antioxidant enzyme genes in immune defense mechanism. • The study gives a new potential biomarker for monitoring iron levels in seawater. - Abstract: The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3 h, ferritin at 24 h, and metallothionein and glutathione peroxidase at 48 h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis

  11. Transcriptomics of in vitro immune-stimulated hemocytes from the Manila clam Ruditapes philippinarum using high-throughput sequencing.

    Directory of Open Access Journals (Sweden)

    Rebeca Moreira

    Full Text Available BACKGROUND: The Manila clam (Ruditapes philippinarum is a worldwide cultured bivalve species with important commercial value. Diseases affecting this species can result in large economic losses. Because knowledge of the molecular mechanisms of the immune response in bivalves, especially clams, is scarce and fragmentary, we sequenced RNA from immune-stimulated R. philippinarum hemocytes by 454-pyrosequencing to identify genes involved in their immune defense against infectious diseases. METHODOLOGY AND PRINCIPAL FINDINGS: High-throughput deep sequencing of R. philippinarum using 454 pyrosequencing technology yielded 974,976 high-quality reads with an average read length of 250 bp. The reads were assembled into 51,265 contigs and the 44.7% of the translated nucleotide sequences into protein were annotated successfully. The 35 most frequently found contigs included a large number of immune-related genes, and a more detailed analysis showed the presence of putative members of several immune pathways and processes like the apoptosis, the toll like signaling pathway and the complement cascade. We have found sequences from molecules never described in bivalves before, especially in the complement pathway where almost all the components are present. CONCLUSIONS: This study represents the first transcriptome analysis using 454-pyrosequencing conducted on R. philippinarum focused on its immune system. Our results will provide a rich source of data to discover and identify new genes, which will serve as a basis for microarray construction and the study of gene expression as well as for the identification of genetic markers. The discovery of new immune sequences was very productive and resulted in a large variety of contigs that may play a role in the defense mechanisms of Ruditapes philippinarum.

  12. Exclusive localization of carbonic anhydrase in bacteriocytes of the deep-sea clam Calyptogena okutanii with thioautotrophic symbiotic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Nakamura, Yoshimitsu; Shimamura, Shigeru; Takaki, Yoshihiro; Uematsu, Katsuyuki; Toyofuku, Takashi; Hirayama, Hisako; Takai, Ken; Nakazawa, Masatoshi; Maruyama, Tadashi; Yoshida, Takao

    2013-12-01

    Deep-sea Calyptogena clams harbor thioautotrophic intracellular symbiotic bacteria in their gill epithelial cells. The symbiont fixes CO2 to synthesize organic compounds. Carbonic anhydrase (CA) from the host catalyzes the reaction CO2 + H2O ↔ HCO3(-) + H(+), and is assumed to facilitate inorganic carbon (Ci) uptake and transport to the symbiont. However, the localization of CA in gill tissue remains unknown. We therefore analyzed mRNA sequences, proteins and CA activity in Calyptogena okutanii using expression sequence tag, SDS-PAGE and LC-MS/MS. We found that acetazolamide-sensitive soluble CA was abundantly expressed in the gill tissue of C. okutanii, and the enzyme was purified by affinity chromatography. Mouse monoclonal antibodies against the CA of C. okutanii were used in western blot analysis and immunofluorescence staining of the gill tissues of C. okutanii, which showed that CA was exclusively localized in the symbiont-harboring cells (bacteriocytes) in gill epithelial cells. Western blot analysis and measurement of activity showed that CA was abundantly (26-72% of total soluble protein) detected in the gill tissues of not only Calyptogena clams but also deep-sea Bathymodiolus mussels that harbor thioautotrophic or methanotrophic symbiotic bacteria, but was not detected in a non-symbiotic mussel, Mytilus sp. The present study showed that CA is abundant in the gill tissues of deep-sea symbiotic bivalves and specifically localizes in the cytoplasm of bacteriocytes of C. okutanii. This indicates that the Ci supply process to symbionts in the vacuole (symbiosome) in bacteriocytes is essential for symbiosis.

  13. Metals bioaccumulation and biomarkers responses in the Neotropical freshwater clam Anodontites trapesialis: Implications for monitoring coal mining areas.

    Science.gov (United States)

    Oliveira, Luciana Fernandes de; Cabral, Millena Terezinha; Vieira, Carlos Eduardo Delfino; Antoniazzi, Matheus Henrique; Risso, Wagner Ezequiel; Martinez, Claudia Bueno Dos Reis

    2016-11-15

    As one of the most impactful industries, coal mining can promote several alterations at surrounding environment. In surface water, elevated concentrations of metals like Mn, Zn, Fe and Al are often observed. Thus, the aim of this study was to investigate the bioaccumulation and the sub-lethal effects of these metals on various organs of the Neotropical bivalve Anodontites trapesialis confined along a stream located near a coal mine, in order to assess a set of biomarkers that could be used for effectively monitoring coal mining areas. Clams were caged, for 96h, at two sites located upstream (Up1 and Up2) and two sites downstream (Dw1 and Dw2) from the mine. Metals bioaccumulation was determined in gills, mantle, digestive gland, muscle and hemolymph and the following biomarkers were measured in A. trapesialis tissues: total antioxidant capacity against peroxyl radicals, metallothionein content, lipid peroxidation (LPO), proteins carbonylation, glutathione S-transferase activity, superoxide dismutase activity and acetylcholinesterase (ACh