Serial analysis of serum cardiac troponin I changes and correlation with clinical findings in 46 dogs with mitral valve disease     

Zoe S. Polizopoulou  Christos K. Koutinas  Anastasia Dasopoulou  Michael Patsikas  Malcolm York  Ian Roman  Mitul Gandhi  Sonal Patel  Alexander F. Koutinas  Peter J. O'Brien 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2014,43(2):218-225

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Effects of changing temperature on benthic marine life in Britain and Ireland     

Keith Hiscock  Alan Southward  Ian Tittley  Stephen Hawkins 《水产资源保护:海洋与淡水生态系统》2004,14(4):333-362

• 1. The coastal waters surrounding Britain and Ireland became warmer during the 20th century and, according to the UK Climate Impact Programme 2002 scenarios of change and other sources, average annual seawater temperatures may rise a further 2°C or more by the 2050s. This warming is part of a global rise in sea‐ and air‐surface temperatures that will cause changes in the distribution and abundance of species.
• 2. Initially, there will not be a wholesale movement northwards of southern species or retreat northwards of northern species, because many additional factors will influence the responses of the different organisms. Such factors include the hydrodynamic characteristics of water masses, the presence of hydrographical and geographical barriers to spread and the life history characteristics (reproductive mode, dispersal capability and longevity) of species. Survey data over the past century show how organisms react to changes of the order of 0.5°C, and in the last two decades, when sea temperatures have risen by as much as 1°C, there have been significant local changes in the distribution of intertidal organisms. These past changes provide a clue to more extensive changes expected in the future if global warming develops as predicted.
• 3. Where species affected by climate change are dominant or key structural or functional species in biotopes, there may be a change in the extent and distribution of those biotopes. Some, dominated by predominantly northern species such as the horse mussel Modiolus modiolus, may decline and reduce their value as rich habitats for marine life. Others, characterized by southern species, for example the sea fan Eunicella verrucosa and the alcyonacean Alcyonium glomeratum, may increase in extent.
• 4. Using information on the life history characteristics of species, their present distribution and other factors, a key supported by a decision tree has been constructed to identify ‘types’ of organism according to their likely response to temperature rise. Conspicuous and easily identified rocky substratum species are good candidates to track change. Using the key, many species are shown as likely to increase their range northwards significantly. In contrast, fewer will decline in abundance and extent in the north. If, as anticipated, global warming continues, then species with distributions already accurately mapped, or being mapped at present, will provide baseline data to test forecasts.

Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Outdoor phytoplankton continuous culture in a marine fish–phytoplankton–bivalve integrated system: combined effects of dilution rate and ambient conditions on growth rate, biomass and nutrient cycling     

Sbastien Lefebvre  Ian Probert  Christel Lefranois  Jrme Hussenot 《Aquaculture (Amsterdam, Netherlands)》2004,240(1-4):211-231

Natural phytoplankton populations were cultured in outdoor continuous cultures using fish-farm effluents as the source of nutrients. The dilution rate was assumed to be the integrating factor of phytoplankton growth and biomass development (flux and stock). In this context, the combined effects of (i) dilution rates of the outdoor culture and (ii) ambient conditions were tested on phytoplankton growth, biomass and cycling of the major nutrient elements (C, N and P). Experiments were carried out in outdoor polyester tanks (0.7 m deep), homogenised by gentle aeration. Si/P ratio was balanced at around 5 in the inflow in order to induce diatom domination while maintaining high N and P assimilation by phytoplankton. Nutrient cycling was assessed through analyses of the different forms of particulate and dissolved nutrients in the inflow and the outflow. Culture dilution rates determined the longevity of the culture and the assimilation efficiency of nutrients. Dissolved phosphorus was the most limiting nutrient. The optimal dilution rate was approximately 0.5 day⁻¹ at 10 °C and 1.5 day⁻¹ at 20 °C with a mean diatom biomass of 9 μM P. Under these conditions, 80% of the dissolved nutrients provided to the tanks were transformed, a production of 8 g C m⁻² day⁻¹ and an assimilation rate of 0.3 g P m⁻² day⁻¹ were recorded. Assimilation by diatoms was the major pathway of nutrient cycling. During the experiment, a bottom sediment developed progressively and this also played an important role in denitrifying the excess dissolved nitrogen in the fish-farm effluent. However, the results showed that diatom biomass can collapse and we hypothesize that this was the consequence of an increase in cellular sinking rates due to cell aggregation under nutrient or light stress. Modelling approaches are needed in future research in order to determine optimal dilution rates taking into account phytoplankton growth rates, nutrient inputs and ambient conditions (e.g. light and temperature).  相似文献   

Application of an electrophoretically detectable genetic marker to ploidy testing in brown trout (Salmo trutta L.) triploidised by heat shock     

Walter W. Crozier  Ian J.J. Moffett 《Aquaculture (Amsterdam, Netherlands)》1989,80(3-4):231-239

A phosphoglucose isomerase (PGI) variant, of brown trout (Salmo trutta L.), expressed in adipose fin tissue, was incorporated into experimental batches through selective crossing of brood-stock having the PGI-3 (110) marker gene. PGI-3 (110) homozygous females were crossed with PGI-3 (100) homozygous males to yield all PGI-3 (110/100) progeny. These were subject to heat shock for 10 min at 28°C, commencing 10 min after insemination. Electrophoretic examination of fry indicated that diploids and triploids were separable on the basis of PGI-3 banding patterns, having staining ratios of 1:2:1 and 4:4:1, respectively. This confirmed the retention of an extra maternal PGI-3 (110) gene in triploid individuals. Potential applications of this marker in triploid studies in brown trout are discussed.  相似文献   

The Value of Seed Potatoes from Four Systems in Kenya     

Wachira Kaguongo  Gladys Maingi  Ian Barker  Nancy Nganga  Joseph Guenthner 《American Journal of Potato Research》2014,91(1):109-118

Although potatoes are the second most valuable crop in Kenya, poor seed potato quality has limited industry expansion. The objectives of this study were to describe the seed potato system, identify problems, determine use of high-quality seed and estimate farmer willingness to pay (WTP) for different types of seed. Data was collected from interviews, forums and surveys. A contingent valuation method (CVM) model was also developed to analyze the factors that influence farmer WTP. It was found that the seed system consists of three sub-components: Formal, Semi-Formal and Farmer. More than 96 % of Kenya seed potatoes were produced in the Farmer category, and were considered to be poor quality. Growers identified bacterial wilt, viral diseases and late blight as the most serious problems. The WTP model revealed that farmer age, distance to seed source, potato training, gender and region were statistically significant explanatory variables. The study recommends that training be conducted to increase production of “clean seed” and “positively-selected seed” in the Semi-Formal part of the seed system.  相似文献   

Allelic losses and gains during translocations of a high conservation value fish,Coregonus lavaretus     

Kim Præbel  Colin W. Bean  Jennifer A. Dodd  Elizabeth C. Etheridge  Andrew R.D. Gowans  Rune Knudsen  Alexander A. Lyle  Peter S. Maitland  Ian J. Winfield  Colin E. Adams 《水产资源保护:海洋与淡水生态系统》2021,31(9):2575-2585

1. The use of translocations to establish new or ‘refuge’ populations for species with high conservation value is controversial but widely used in conservation management. One of the risks of this approach is that an establishing population does not adequately capture the genetic diversity of the donor gene pool. This effect, rarely examined, is tested here.
2. In this study the genetic consequences of two conservation translocations after five generations (16 years) of the European whitefish, Coregonus lavaretus, were quantified. Both translocations were made using almost the same genetic groups and thus represent a partly replicated natural study.
3. Analysis of 12 informative microsatellites showed that expected heterozygosity, the mean number of alleles per locus and allelic richness did not differ between donor and translocated populations. There was also no loss of heterozygosity in the translocated populations, nor deviations from Hardy–Weinberg equilibrium expectations, nor signs of linkage disequilibrium.
4. All populations were genetically differentiated but pairwise F_ST values were low, indicating that the magnitude of divergence was small.
5. There was no evidence of inbreeding but there were significant differences in private allelic richness between donor and translocated populations. Of 50 alleles found in the donor population, 16% of the rarer alleles were lost in one translocated population and 8% in the other.
6. Allele loss without a reduction in heterozygosity strongly points to stochastic drift effects having occurred following translocation. The evidence indicates that alleles that were not detected in the donor population have arisen de novo in the translocated populations.
7. It is concluded that conservation translocations comprising even a modest number of propagules can successfully capture a high proportion of genetic variation of the host population, and that reduced genetic variation in the translocated population may be mitigated by the emergence of new variation over short time periods.

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Ditch communities: a major contributor to floodplain biodiversity     

Patrick D. Armitage  Krzysztof Szoszkiewicz  John H. Blackburn  Ian Nesbitt 《水产资源保护:海洋与淡水生态系统》2003,13(2):165-185

• 1. Chalk stream floodplains are extensively managed and the high degree of connectivity associated with water meadows has been severely reduced. The main contributor to aquatic biodiversity is perceived to be the river itself. Ditches in these areas have been largely ignored as a contributor to total diversity.
• 2. Separate surveys of instream, bankside and ditch macroinvertebrates in a small area of floodplain provided a unique opportunity to assess the relative contribution of each locality to total aquatic diversity. The fauna and flora of a ditch on the lower River Frome floodplain was examined and compared with studies of adjacent bankside and instream habitat. A total of 145 macroinvertebrate taxa and 61 plant species were recorded from the ditch. Faunal abundance and richness were positively related to the diversity of aquatic plants. The ditch showed a clear linear trend in community type that appeared to be partly related to the acidic seepage from tertiary deposits at the source and percentage cover of vegetation.
• 3. There were large differences in the numbers of taxa collected in ditch, bankside, instream mesohabitat and RIVPACS surveys. Of the total 202 taxa recorded in the four surveys, the ditch contributed 59 unique taxa with 25 from the bankside and two and three from the mesohabitat and RIVPACS surveys, respectively.
• 4. The large contribution of the Rushton Ditch to aquatic biodiversity on the floodplain is due to three main factors: the chemically different and slow‐flowing environment, the connection to the main river, and a management regime which has halted hydroseral succession at a point where vegetation structure is for the most part open and able to support a wide range of ecological niches. The maintenance of these conditions requires sensitive management and further knowledge of the needs and interactions of faunal communities with vegetation.

Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Hybridization in Australian Freshwater Crayfish—Production of All-Male Progeny     

Craig S.  Lawrence Noel M.  Morrissy Philip E.  Vercoe Ian H.  Williams 《Journal of the World Aquaculture Society》2000,31(4):651-658

Abstract.— In freshwater crayfish aquaculture high densities can result from uncontrolled reproduction. Hence some farmers manually sex yabbies Cherax albidus and stock only mate crayfish in farm dams or ponds. Although male-only yabby populations produce an estimated 70% increase in gross income, hand sexing is time consuming and prone to error. A hybridization experiment using freshwater crayfish from the yabby species complex, collected from geographically isolated regions throughout Australia, revealed a hybrid between Cherax rotundus females and C. albidus males which consistently produces only male progeny. This has been confirmed in nine crosses of the same two species. The reciprocal cross of C. albidus females × C. rotundus males produces both male and female progeny. The consistent production of only male progeny by hybridization has not been recorded previously for a crustacean.  相似文献   

IMAGING DIAGNOSIS—AVULSION OF THE MEDIAL COLLATERAL LIGAMENT OF THE TARSUS IN A HORSE     

Patricia L.  Rose  DVM  MS  Ian  Moore DVM 《Veterinary radiology & ultrasound》2003,44(6):657-659

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Innovations in Fish Passage Technology     

Ian Cowx 《Fisheries Management and Ecology》2000,7(5):471-472

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