Oxidative damage in rainbow trout caged in a polluted river   总被引：1，自引：0，他引：1  

Carney Almroth B  Sturve J  Förlin L 《Marine environmental research》2008,66(1):90-91

Sewage treatment works (STWs) are a common source of chemicals entering into the aquatic environment. In order to assess effects of these effluents on oxidative stress parameters in aquatic organisms, we caged rainbow trout at five sites: upstream, near an STW effluent, and three sites downstream in the river Viskan in western Sweden for 14 days during autumn, 2006. We then measured protein carbonyls in plasma as well as 20S proteosome activity and lipid peroxidation products, i.e. MDA and 4-HNE, in liver samples. Levels of both lipid and protein oxidative damage products were elevated in fish caged near the STW effluent while 20S activity showed no differences. This argues that complex mixtures of chemicals entering into the aquatic environment do have deleterious effects on fish. Additionally, oxidative stress parameters can serve as a biomarker in aquatic organisms.  相似文献   

Ground Motion Relations While TBM Drilling in Unconsolidated Sediments     

Michael Grund  Joachim R. R. Ritter  Manuel Gehrig 《Rock Mechanics and Rock Engineering》2016,49(5):1773-1787

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The effects of artificial ammonium enhancement on riverine periphytic diatom communities   总被引：2，自引：0，他引：2  

Joachim Hürlimann  Ferdinand Schanz 《Aquatic Sciences - Research Across Boundaries》1993,55(1):40-64

An experiment to ascertain the influence of artificially enhanced ammonium concentrations on riverine periphytic diatom communities was conducted during an 80 day period in winter 1988/89 (temperature: 5°C). During an initial 47 day enrichment phase, ammonium chloride at different concentrations was added to O₂-saturated river water in experimental channels. Compared to a control, the addition of 1.2 mg NH ₄ ⁺ -N·l^–1 resulted in only slight changes in the species composition of the diatom community. The addition of 5.1 mg NH ₄ ⁺ -N·l^–1 and more (60 µg NH₃-N·l^–1) resulted in a decrease in the biomass and a drastic change in the species composition. After the 42 day enrichment period, the diatom speciesFragilaria capucina var.vaucheriae, Navicula saprophila, Navicula atomus andGomphonema parvulum, all of which are known to be tolerant to organic pollution, were found with relative abundances of 44.8%, 35.6%, 2.3% and 1.5%, respectively. Changes in species composition of the periphytic diatom communities occurred within the first two weeks of the subsequent recovery phase. After a month of recovery, all periphytic diatom communities exhibited a high degree of structural similarity with the control.  相似文献   

Stratospheric aerosol sulfuric acid: First direct in situ measurements using a novel balloon-based mass spectrometer apparatus     

Frank Arnold  Joachim Curtius  Stefan Spreng  Terry Deshler 《Journal of Atmospheric Chemistry》1998,30(1):3-10

The first direct in situ measurements of the sulfuric acid contained in stratospheric aerosol particles were made using a novel balloon-based Ion Molecule Reaction Mass Spectrometer instrument (IMRMS) equipped with an aerosol vaporizer. The IMRMS method employed offers direct aerosol sulfuric acid measurements with high spatial resolution. The balloon flight took place on 23 October 1995 in middle latitudes (44°N) and reached a maximum altitude of 24 km. Measured molecular number densities of aerosol sulfuric acid decreased with increasing altitude from about 2.9 × 109 cm-3 at 15km altitude to about 2.4 × 108 cm-3 at 21 km. Corresponding mass mixing ratios are 2.5 and 0.6 ppbm, respectively. Calculated sulfuric acid mixing ratios from aerosol volumes inferred from aerosol size distribution measurements on the same balloon agree well with the IMRMS data using standard assumption aerosol composition.  相似文献   

Dark matter haloes within clusters     

Sebastiano Ghigna  Ben Moore  Fabio Governato  George Lake  Thomas Quinn  & Joachim Stadel 《Monthly notices of the Royal Astronomical Society》1998,300(1):146-162

We examine the properties of dark matter haloes within a rich galaxy cluster using a high-resolution simulation that captures the cosmological context of a cold dark matter universe. The mass and force resolution permit the resolution of 150 haloes with circular velocities larger than 80 km s⁻¹ within the cluster virial radius of 2 Mpc (with Hubble constant H ₀ = 50 km s⁻¹ Mpc⁻¹). This enables an unprecedented study of the statistical properties of a large sample of dark matter haloes evolving in a dense environment. The cumulative fraction of mass attached to these haloes varies from close to zero per cent at 200 kpc to 13 per cent at the virial radius. Even at this resolution the overmerging problem persists; haloes that pass within 100–200 kpc of the cluster centre are tidally disrupted. Additional substructure is lost at earlier epochs within the massive progenitor haloes. The median ratio of apocentric to pericentric radii is 6:1, so that the orbital distribution is close to isotropic, circular orbits are rare and radial orbits are common. The orbits of haloes are unbiased with respect to both position within the cluster and the orbits of the smooth dark matter background, and no velocity bias is detected. The tidal radii of surviving haloes are generally well-fitted using the simple analytic prediction applied to their orbital pericentres. Haloes within clusters have higher concentrations than those in the field. Within the cluster, halo density profiles can be modified by tidal forces and individual encounters with other haloes that cause significant mass loss —'galaxy harassment'. Mergers between haloes do not occur inside the cluster virial radius.  相似文献   

A stabilization procedure for the differential equations of the symmetric gyroscope including perturbing torques     

Joachim Baumgarte  Wolfgang von Grünhagen 《Celestial Mechanics and Dynamical Astronomy》1979,20(2):173-178

This paper shows that for the free symmetric top a formulation of the equations of motion is possible, which is Liapunov stable. The formalism applied is equivalent to the conservative stabilization of the Keplerian problem. The perturbed problem appears in -stable form. This stabilization procedure could be useful in celestial mechanics, if the gyroscopic motion of a satellite is considered and one is interested in the exact position of the angles.  相似文献   

Zur Entstehung der Nabburger Fln\spatlagerstätten     

Joachim Köhler 《International Journal of Earth Sciences》1941,32(1-2):71-92

Ohne ZusammenfassungAm Schlu\ meiner Arbeit möchte ich meinem hochverehrten Lehrer, Herrn Prof. Dr. F.Angel (Graz), für seine Anregungen und ständige Anteilnahme meinen allerbesten Dank aussprechen. Meinem lieben KameradenSiegfried Däweritz, Mei\en, danke ich herzlich für die Zeichnung von Abbildungen während des Feldzuges in Frankreich.  相似文献   

Observations of the mass and flow field at Porcupine Bank     

Mohn  Christian; Bartsch  Joachim; Meincke  Jens 《ICES Journal of Marine Science》2002,59(2):380-392

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Purification of two crab-paralysing polypeptides from the sea anemone Bolocera tuediae     

Lszlo Bress  Joachim Zwick 《Marine Chemistry》1980,8(4):333-338

Two toxic polypeptides BTTX I and BTTX II were isolated from the sea anemone Bolocera tuediae. Toxin isolation was achieved by alcoholic extraction of the homogenized tentacles and filaments, batchwise adsorption onto ion-exchangers (QAE-Sephadex A25, CM-Cellulose, Se-Cellulose, Sp-Sephadex C25), gel filtration on Sephadex G50 and G25 and ion-exchange chromatography on SP-Sephadex C25 and QAE-Sephadex A25. The toxins were tested on the shore crab Carcinus maenas by intramuscular injection. LD₁₀₀ for BTTX I is 500 μg kg⁻¹ C. maenas, whereas the BTTX II it is 40 μg kg⁻¹. The molecular weights of both toxins are estimated to be 5000 Dalton.  相似文献   

Time-series of surface water CO₂ and oxygen measurements on a platform in the central Arkona Sea (Baltic Sea): Seasonality of uptake and release   总被引：1，自引：1，他引：1  

Joachim Kuss  Wolfgang Roeder  K.-Peter Wlost  Michael D. DeGrandpre 《Marine Chemistry》2006,101(3-4):220-232

High resolution measurements of carbon dioxide and oxygen were made in surface waters of the central Arkona Sea (Baltic Sea) from May 2003 to September 2004. Sensors for CO₂ partial pressure (pCO₂^w) and oxygen (O₂) concentration were mounted in 7 m depth on a moored platform which is used for hydrographic and meteorological monitoring. The pCO₂^w data were obtained in half hour intervals and O₂ was measured each hour as an average of a 10 min measurement. To check the performance of the sensors, pCO₂^w and O₂ were determined by shipboard measurements on a research vessel which visited the site in 1–2 month intervals. In addition, pCO₂^w was measured on a “volunteer observing ship” (VOS) passing the platform each second day at a distance of about 25 km. Minima of 220 to 250 μatm of pCO₂^w were observed at the time of the spring bloom and a cyanobacteria bloom in mid-summer. During winter the pCO₂^w was mostly close to equilibrium with the atmosphere but maxima of 430 to 530 μatm were also observed. The seasonality of oxygen and pCO₂^w showed an opposing pattern. From a multiple regression analysis, we concluded that two processes primarily controlled pCO₂^w during our study: biological turnover and mixing. A parameterization, based on apparent oxygen utilisation (AOU) and salinity (S) only (pCO₂^w = 1.23 AOU + 43 S), reproduced the seasonality of pCO₂^w in surface water reasonably well. Based on our pCO₂, salinity, and temperature data set, we attempted to separate processes changing total inorganic carbon concentrations (C_T) by using an alkalinity–salinity relation for the area. The contribution of CO₂ gas exchange and mixing were calculated and from this the biological turnover was deduced to reveal the calculated C_T changes.The net annual uptake of CO₂ in the central Arkona Sea was estimated to be about 1.5 Tg (1.5·10¹² g) which was approximately balanced by a net oxygen release considering the uncertainties of the flux calculations. Near-coast CO₂ emission due to episodic upwelling partly compensated the uptake of the central part of the Arkona Sea reducing the overall magnitude of the CO₂ uptake.  相似文献