ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Turbulence  (3)
  • Immunization  (1)
  • American Geophysical Union  (3)
  • Springer  (1)
  • 2010-2014  (3)
  • 1980-1984  (1)
  • 1
    ISSN: 1432-1955
    Keywords: Capillaria hepatica ; X-ray attenuation ; Immunization ; Capillaria hepatica ; Röntgenstrahlenaltenuierung ; Immunisierung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Der Einfluß von Erstinfektionen mit embryonierten Eiern, von röntgenattenuierten Stadien, von nicht embryonierten Eiern und löslichen Eiextrakten auf Belastungsinfektionen mitCapillaria hepatica wurde untersucht. Die Reproduktivität einer Wurmpopulation aus einer subletalen Belastungsinfektion wurde inMastomys natalensis durch eine 11 Tage vorher gesetzte Erstinfektion mit 50, 150, 400 oder 800 embryonierten Eiern/Tier signifikant reduziert. Ein signifikanter Einfluß von röntgenattenuierten, infektiösen Eiern bzw. von intraperitoneal injizierten, nicht embryonierten Eiern (bei steigenden Dosen über 10 Tage wurde die Eiproduktion normaler Infektionen simuliert) beschränkte sich auf schwache (50 Eier/Tier) Belasnungsinfektionen. Die Kombination attenuierten Infektionsmaterials mit nicht embryonierten Eiern i.p. führte zu keiner gesteigerten Wirkung. In Albinomäusen ließ sich durch vorherige, wiederholte subkutane Injektion von löslichen Eiextrakten die Eiproduktion einer mittleren Belastungsinfektion bis zum 60. Tag p.i. hochsignifikant reduzieren. Die durch Infektionsdosen von 230 embryonierten Eiern/g Körpergewicht beiM. natalensis zwischen dem 20. und 35. Tag p.i. 100% erreichende Mortalität ließ sich durch vorherige Applikation von 50, 150, 400 und 800 Eiern/Tier bei nach 36 und 52 Tagen gesetzten Belastungsinfektionen auf 0–30% reduzieren. Bei Verwendung attenuierten Infektionsmaterials war für einen 70–80% igen Schutz eine wiederholte Vakzinierung notwendig. Die intraperitoneale Injektion von nicht embryonierten Eiern führte bei 40% der Tiere zu einem Schutz. Der Eintritt des Todes verzögerte sich i.d.R. bei vorbehandelten Tieren.
    Notes: Abstract The influence of primary infections with embryonated infective eggs or with X-irradiated infective eggs, and of non-embryonated eggs, and egg homogenate extracts on challenge infections withCapillaria hepatica was investigated. The worm reproductivity was significantly suppressed in a sublethal challenge infection given 11 days after a primary infection ofMastomys natalensis with 50, 150, 400, and 800 eggs per animal. The administration of 600 X-irradiated (2.2 Krd) embryonated eggs 36 days before challenge as well as an intraperitoneal injection of non-embryonated eggs 12, 10, 8, 6, 4, and 2 days before challenge (simulating the egg production of a normal infection) also reduced significantly the egg production of a weak (50 eggs/animal) infection. No effect was observed on a moderate challenge (300 eggs/animal). The effect was not markedly enhanced by the repeated administration of X-irradiated eggs or by the combination of X-irradiated infective eggs and non-embryonated eggs. Immunization of mice with soluble egg extracts resulted in significant reduction of egg production determined 60 days after challenge. Two hundred and thirty eggs ofC. hepatica/g bodyweight proved to be a lethal infection dose forM. natalensis. The animals died between 20 and 35 days after infection. After single infections with 50, 150, 400, or 800 eggs per animal the mortality ofMastomys challenged 36 or 52 days later was reduced to 0–30%. Using X-irradiated embryonated eggs for immunization only repeated administration led to protection in 70 to 80% of the animals. About 40% of the animals could be protected by the intraperitoneal injection of non-embryonated eggs. If death occurred it was delayed. The combination of X-irradiated stages and eggs did not enhance the protection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C05004, doi:10.1029/2003JC002094.
    Description: Rates of turbulent kinetic energy (TKE) production and buoyancy flux in the region immediately seaward (~1 km) of a highly stratified estuarine front at the mouth of the Fraser River (British Columbia, Canada) are calculated using a control volume approach. The calculations are based on field data obtained from shipboard instrumentation, specifically velocity data from a ship mounted acoustic Doppler current profiler (ADCP), and salinity data from a towed conductivity-temperature-depth (CTD) unit. The results allow for the calculation of vertical velocities in the water column, and the total vertical transport of salt and momentum. The vertical turbulent transport quantities (inline equation, inline equation) can then be estimated as the difference between the total transport and the advective transport. Estimated production is on the order of 10−3 m2 s−3, yielding a value of ɛ(νN2)−1 on the order of 104. This rate of TKE production is at the upper limit of reported values for ocean and coastal environments. Flux Richardson numbers in this highly energetic system generally range from 0.15 to 0.2, with most mixing occurring at gradient Richardson numbers slightly less than inline equation. These values compare favorably with other values in the literature that are associated with turbulence observations from regimes characterized by scales several orders of magnitude smaller than are present in the Fraser River.
    Description: This work was performed as a part of D. MacDonald’s Ph.D. thesis, and was funded by Office of Naval Research grants N000-14-97-10134 and N000-14-97- 10566, National Science Foundation grant OCE-9906787, a National Science Foundation graduate fellowship, and support from the WHOI Academic Programs Office.
    Keywords: Turbulence ; Entrainment ; Estuary
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 37 (2010): L22607, doi:10.1029/2010GL045272.
    Description: Shear instability is the dominant mechanism for converting fluid motion to mixing in the stratified ocean and atmosphere. The transition to turbulence has been well characterized in laboratory settings and numerical simulations at moderate Reynolds number—it involves “rolling up”, i.e., overturning of the density structure within the cores of the instabilities. In contrast, measurements in an energetic estuarine shear zone reveal that the mixing induced by shear instability at high Reynolds number does not primarily occur by overturning in the cores; rather it results from secondary shear instabilities within the zones of intensified shear separating the cores. This regime is not likely to be observed in the relatively low Reynolds number flows of the laboratory or in direct numerical simulations, but it is likely a common occurrence in the ocean and atmosphere.
    Description: This research was supported by NSF grant OCE‐0824871 and ONR grant N00014‐0810495.
    Keywords: Stratification ; Turbulence ; Mixing
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 115 (2010): C12024, doi:10.1029/2009JC006061.
    Description: Turbulent mixing of salt is examined in a shallow salt wedge estuary with strong fluvial and tidal forcing. A numerical model of the Merrimack River estuary is used to quantify turbulent stress, shear production, and buoyancy flux. Little mixing occurs during flood tides despite strong velocities because bottom boundary layer turbulence is dislocated from stratification elevated in the water column. During ebbs, bottom salinity fronts form at a series of bathymetric transitions. At the fronts, near-bottom velocity and shear stress are low, but shear, stress, and buoyancy flux are elevated at the pycnocline. Internal shear layers provide the dominant source of mixing during the early ebb. Later in the ebb, the pycnocline broadens and moves down such that boundary layer turbulence dominates mixing. Mixing occurs primarily during ebbs, with internal shear mixing accounting for about 50% of the total buoyancy flux. Both the relative contribution of internal shear mixing and the mixing efficiency increase with discharge, with bulk mixing efficiencies between 0.02 and 0.07. Buoyancy fluxes in the estuary increase with discharge up to about 400 m3 s−1 above which a majority of the mixing occurs offshore. Observed buoyancy fluxes were more consistent with the k-ɛ turbulence closure than the Mellor-Yamada closure, and more total mixing occurred in the estuary with k-ɛ. Calculated buoyancy fluxes were sensitive to horizontal grid resolution, as a lower resolution grid yielded less integrated buoyancy flux in the estuary and exported lower salinity water but likely had greater numerical mixing.
    Description: This research was funded by National Science Foundation Grant OCE‐0452054. Ralston also received support from The Penzance Endowed Fund in Support of Assistant Scientists and The John F. and Dorothy H. Magee Fund in Support of Scientific Staff at Woods Hole Oceanographic Institution.
    Keywords: Mixing ; Turbulence ; Salt wedge estuary
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...