Littoral spawning habitats of three southern Arctic charr (Salvelinus alpinus L.) populations     

Jonathan J. Low  Fran Igoe  John Davenport  Simon S. C. Harrison 《Ecology of Freshwater Fish》2011,20(4):537-547

Abstract Arctic charr populations in southern latitudes are nonmigratory, with all life‐stages limited to freshwater lakes and in‐ or out‐flowing tributaries. Although many of these populations are reported to also spawn in lake littorals, little is known about the physical characteristics of putative spawning grounds. A total of 23 discrete spawning sites within three Irish lakes were located by fyke netting of spawning adults and snorkelling in littoral habitats. Spawning sites were found to be long, narrow strips running parallel to the shore at a maximum depth of 124 cm. Spawning sites were limited to areas of coarse mineral substrate with an adequate (c. 8 cm) depth of clean interstitial spaces. In individual lakes, combined areas of spawning sites made up 0.4–0.7% of available littoral. Egg densities varied considerably between sites (33–900·eggs m^?2) and were significantly correlated with gradient and width of spawning sites. No evidence of redd digging was found. The shallow, localised and restricted nature of spawning grounds makes such populations vulnerable to anthropogenically induced postoviposition changes in surface water level, eutrophication processes such as increased lake sedimentation and elevated nutrient status.  相似文献   

Prevalence of feline herpesvirus 1, Chlamydophila felis, and Mycoplasma spp DNA in conjunctival cells collected from cats with and without conjunctivitis   总被引：1，自引：0，他引：1  

Low HC  Powell CC  Veir JK  Hawley JR  Lappin MR 《American journal of veterinary research》2007,68(6):643-648

OBJECTIVE: To use PCR assays to determine the prevalence of feline herpesvirus 1 (FHV-1), Chlamydophila felis, and Mycoplasma spp DNA in conjunctival cells collected from cats with and without conjunctivitis; to compare results of conventional and real-time fluorogenic PCR assays for amplification of FHV-1 DNA; and to determine whether copy numbers of FHV-1 DNA are correlated with conjunctivitis. ANIMALS: 55 cats with active conjunctivitis, 39 healthy cats that never had conjunctivitis, and 32 cats with a history of conjunctivitis that had been resolved for at least 3 months. PROCEDURES: Samples were obtained by rolling cotton-tipped applicators on the ventral conjunctiva of awake cats treated topically with proparacaine. The DNA was extracted from the swab specimens and assessed in PCR assays to detect DNA of FHV-1 (fluorogenic PCR assay and conventional PCR assay), Mycoplasma spp (conventional PCR assay), and C felis (conventional PCR assay). RESULTS: Overall prevalence rates of FHV-1, C felis, and Mycoplasma spp as assessed by the conventional PCR assays were 6.7%, 3.2%, and 9.6%, respectively. Percentage concordance between conventional PCR and fluorogenic PCR assays for FHV-1 was 92.5%. There were no significant differences among the 3 groups of cats for the mean copy number of FHV-1 divided by the copy number of glyceraldehyde-3-phosphate dehydrogenase. CONCLUSIONS AND CLINICAL RELEVANCE: Mycoplasma spp were the most prevalent organism detected and was associated with conjunctivitis. This study could not confirm that there are increased copy numbers of FHV-1 DNA in cats with conjunctivitis, compared with the copy numbers for cats without conjunctivitis.  相似文献   

Renal disease     

C A Osborne  D G Low  K H Johnson 《The Veterinary clinics of North America》1971,1(2):323-353

  相似文献   

Epidemiological Observations in a Corriedale Flock affected by Brucella ovis     

Robles  C.A.  Uzal  F.A.  Olaechea  F.V.  Low  C. 《Veterinary research communications》1998,22(7):435-443

Brucellosis in sheep, caused by Brucella ovis, is primarily a chronic infectious disease of rams with epididymitis as its most characteristic lesion. Six hundred rams from an infected farm were clinically and serologically examined once a year, over a 3-year period. An increase from 2.1% to 6.3% in the prevalence of animals serologically positive to B. ovis occurred over the 3 years. However, the prevalence of rams with lesions in the reproductive tract declined from 14.2% to 6.5% in the third year following one year of strict culling of clinically affected and rams that were serologically positive for B. ovis. Clinical lesions found in the 179 affected rams fell into two main categories: rams with epididymitis and rams with affected lymph nodes. These results suggest that the prevalence of the disease relates mainly to the sexual activity of the animal and not to age in itself. A single cull based on the results of clinical examination and serological test results was unable to decrease the prevalence of B. ovis in an extensive Corriedale sheep flock.  相似文献   

Effects of herbicides and herbicide analogs on [¹⁴C]leucine incorporation by suspension-cultured Solanum nigrum cells     

M.A. Egli  D. Low  K.R. White  J.A. Howard 《Pesticide biochemistry and physiology》1985,24(1):112-118

Assays of [¹⁴C]leucine incorporation were used to measure effects of herbicides on suspensioncultured heterotrophic Solanum nigrum cells. Most herbicidal vs. nonherbicidal chemicals in a set of 47 compounds could be distinguished from each other based on their extent of inhibition of leucine incorporation by S. nigrum cells. Herbicides which failed to inhibit leucine incorporation were photosynthetic inhibitors. Both phytotoxic and nonphytotoxic thiocarbamate analogs (as determined by whole-plant studies) tended to inhibit leucine incorporation. It was concluded that the leucine incorporation screen could detect a majority of compounds tested which are herbicidal, and that it may also be useful to detect compounds which have cellular toxicity which is not observed in the whole plant.  相似文献   

Histophilus ovis epididymitis in a ram in the UK   总被引：1，自引：0，他引：1  

J C Low  M M Graham 《The Veterinary record》1985,117(3):64-65

  相似文献   

Cryptosporidium infection in a dugong (Dugong dugon)     

BD HILL  IR FRASER  HC PRIOR 《Australian veterinary journal》1997,75(9):670-671

  相似文献   

A motorized grinder for making soil thin sections     

Alison J. Low  Eric J. Low  Lowell A. Douglas 《Geoderma》1984,32(4):335-337

A small hand-held device is described which enables an operator to grind soil thin sections very rapidly as compared to conventional hand grinding. The apparatus is relatively inexpensive and easy to construct as it comprises only a simple motorized grinder and grit impregnated discs 2.5 cm in diameter.  相似文献   

Early results from the infrared astronomical satellite     

Neugebauer G  Beichman CA  Soifer BT  Aumann HH  Chester TJ  Gautier TN  Gillett FC  Hauser MG  Houck JR  Lonsdale CJ  Low FJ  Young ET 《Science (New York, N.Y.)》1984,224(4644):14-21

For 10 months the Infrared Astronomical Satellite (IRAS) provided astronomers with what might be termed their first view of the infrared sky on a clear, dark night. Without IRAS, atmospheric absorption and the thermal emission from both the atmosphere and Earthbound telescopes make the task of the infrared astronomer comparable to what an optical astronomer would face if required to work only on cloudy afternoons. IRAS observations are serving astronomers in the same manner as the photographic plates of the Palomar Observatory Sky Survey; just as the optical survey has been used by all astronomers for over three decades, as a source of quantitative information about the sky and as a "roadmap" for future observations, the results of IRAS will be studied for years to come. IRAS has demonstrated the power of infrared astronomy from space. Already, from a brief look at a miniscule fraction of the data available, we have learned much about the solar system, about nearby stars, about the Galaxy as a whole and about distant extragalactic systems. Comets are much dustier than previously thought. Solid particles, presumably the remnants of the star-formation process, orbit around Vega and other stars and may provide the raw material for planetary systems. Emission from cool interstellar material has been traced throughout the Galaxy all the way to the galactic poles. Both the clumpiness and breadth of the distribution of this material were previously unsuspected. The far-infrared sky away from the galactic plane has been found to be dominated by spiral galaxies, some of which emit more than 50 percent and as much as 98 percent of their energy in the infrared-an exciting and surprising revelation. The IRAS mission is clearly the pathfinder for future missions that, to a large extent, will be devoted to the discoveries revealed by IRAS.  相似文献   

Gonadotroph-specific expression of metallothionein fusion genes in pituitaries of transgenic mice   总被引：4，自引：0，他引：4  

M J Low  R M Lechan  R E Hammer  R L Brinster  J F Habener  G Mandel  R H Goodman 《Science (New York, N.Y.)》1986,231(4741):1002-1004

Transgenic mice expressing a metallothionein-somatostatin fusion gene contain high concentrations of somatostatin in the anterior pituitary gland, a tissue that does not normally produce somatostatin. Immunoreactive somatostatin within the anterior pituitaries was found exclusively within gonadotrophs. Similarly, a metallothionein-human growth-hormone fusion gene was also expressed selectively in gonadotrophs. It is proposed that sequences common to the two fusion genes are responsible for the gonadotroph-specific expression.  相似文献