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71.
Magnetic resonance images were acquired of the brain of a 7-year-old male Golden Retriever with hydrocephalus secondary to a medullary lesion. Images were acquired prior to and 4 weeks following surgical treatment for the hydrocephalus, and the dog was euthanased following the second imaging session. The MR images demonstrated a medullary lesion with patchy but predominantly hyperintense signal with both T1- and T2-weighting, within which small areas of low signal were scattered. There was little edema associated with this lesion and no enhancement with gadolinium. Postmortem examination revealed the medullary mass to be a dermoid cyst. Several small nodular lesions were identified within the central nervous system on the magnetic resonance images whose origin was uncertain on postmortem examination.  相似文献   
72.
A popular species for food and sport, the European catfish (Silurus glanis) is well‐studied in its native range, but little studied in its introduced range. Silurus glanis is the largest‐bodied freshwater fish of Europe and is historically known to take a wide range of food items including human remains. As a result of its piscivorous diet, S. glanis is assumed to be an invasive fish species presenting a risk to native species and ecosystems. To assess the potential risks of S. glanis introductions, published and ‘grey’ literature on the species’ environmental biology (but not aquaculture) was extensively reviewed. Silurus glanis appears well adapted to, and sufficiently robust for, translocation and introduction outside its native range. A nest‐guarding species, S. glanis is long‐lived, rather sedentary and produces relatively fewer eggs per body mass than many fish species. It appears to establish relatively easily, although more so in warmer (i.e. Mediterranean) than in northern countries (e.g. Belgium, UK). Telemetry data suggest that dispersal is linked to flooding/spates and human translation of the species. Potential impacts in its introduced European range include disease transmission, hybridization (in Greece with native endemic Aristotle’s catfish [Silurus aristotelis]), predation on native species and possibly the modification of food web structure in some regions. However, S. glanis has also been reported (France, Spain, Turkmenistan) to prey intensively on other non‐native species and in its native Germany to be a poor biomanipulation tool for top‐down predation of zooplanktivorous fishes. As such, S. glanis is unlikely to exert trophic pressure on native fishes except in circumstances where other human impacts are already in force. In summary, virtually all aspects of the environmental biology of introduced S. glanis require further study to determine the potential risks of its introduction to novel environments.  相似文献   
73.
Almaco jack (Seriola rivoliana Valenciennes) is an excellent candidate for aquaculture due to its fast growth rate and high market value. While S. rivoliana have adapted well to captivity, survival at early life stages can be improved to increase profitability during production. A wide range of variables cause larval mortalities but high bacterial loads in rearing tanks are often correlated with these losses. The aim of this study was to investigate the effect of egg disinfection on bacterial load and hatch rate of S. rivoliana. Disinfectants tested included formalin (F100 and F200; 100 and 200 mg/L, respectively, for 60 min), hydrogen peroxide (HPO; 300 mg/L for 10 min) and peracetic acid/hydrogen peroxide (PAA/HPO; 15.7 mg/L/39.6 mg/L for 1 min). Concentrations and contact times were determined based on current use in marine aquaculture and preliminary trials. Eggs treated with HPO and F100 had significantly higher hatch rates than the untreated control group. All treatments significantly decreased total Vibrio counts compared to untreated eggs; however, total bacterial counts were only decreased following treatments with PAA/HPO and F200. To prevent egg mortality due to bacterial overgrowth, consideration should be given to the use of surface disinfection using HPO or F100. Future studies should investigate the use of peracetic‐based products at lower doses.  相似文献   
74.
Journal of Crop Science and Biotechnology - Maize (Zea mays L.) is the most important cereal crop in sub-Saharan Africa. However, its production is constrained by many factors including low yields...  相似文献   
75.
High concentrations of the mycotoxins HT-2 and T-2 (HT2?+?T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2?+?T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2?+?T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2?+?T2 in oat grains. Our data show that adequate predictions of the risk of HT2?+?T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2?+?T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2?+?T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2?+?T2 accumulation in oat grains. Our data indicated that HT2?+?T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.  相似文献   
76.
Anticoagulant rodenticides (ARs) are considered inhumane, show increasingly limited efficacy due to acquired resistance, and carry environmental consequences associated with non-target species uptake. In a questionnaire study of 499 UK farms that all deployed chemical rodenticide we found a high mean reliance (79%), on second generation ARs with just over half of the respondents using no other rodent control methods. Additional methods where deployed, alone or in combination, included predation (41%), kill-trap deployment (16%) and shooting (1%). Nearly 40% of all respondents deployed rodenticides year-round. There was no evidence to suggest that “tidy-farm” measures, such as clearing food spills and minimising on-farm rodent harbourage sites aimed at minimising rodent-associated problems, were associated with a lower likelihood of year-round deployment; in fact trends in our analyses suggested the opposite. We therefore encourage operators to fully evaluate the true necessity of rodenticide deployment before AR use.  相似文献   
77.
Microbial communities in soils provide numerous functions vital to agricultural productivity, and there is growing interest in understanding and manipulating these communities to achieve more sustainable production systems. We investigated microbial communities in potato fields in Wisconsin to determine the extent to which microbial communities were structured by inherent soil properties versus factors under grower control. We found that soil properties, including texture and chemistry, shaped microbial communities at broad levels, determining the diversity and abundance of phyla. Organic versus conventional management, however, correlated with finer scale differences in microbial communities, while crop variety was not associated with microbial community composition in this study. These results suggest that grower practices have the potential to alter microbial communities, but these effects will take place within an existing soil context. Future research is necessary to determine how these patterns in microbial community structure relate to functional outcomes for plant health.  相似文献   
78.
79.
Vernalization insensitivity is a key feature of domesticated chickpea, and its genetic basis is not well understood. We studied vernalization response among hybrid progeny derived from two domesticated × wild crosses. The wild parents are vernalization‐sensitive, late‐flowering genotypes while both domesticated parents are vernalization insensitive. Parental lines and hybrid progeny were tested with (28 days at 4°C) and without vernalization (control). The difference in mean days to flower (?DTF) between control and vernalization treatments was used to assess the flowering vernalization response. A wide range of ?DTF values was observed among the hybrid progeny. Strong genotype by environment interaction effect on ?DTF was observed for the parental accessions and hybrid progeny. We used the ?DTF values to select vernalization responsive and non‐responsive progeny lines. However, the genotype × environment interaction strongly interfered with our selection. Chickpea breeders interested in using the wild progenitor as a donor of exotic traits should be aware of the possibility of introducing vernalization response alleles that may alter the phenology of their breeding materials in an unpredictable manner.  相似文献   
80.
Bottom trawling (nets towed along the seabed) spread around the British Isles from the 1820s, yet the collection of national fisheries statistics did not begin until 1886. Consequently, analysis of the impacts of trawling on fish stocks and habitats during this early period is difficult, yet without this information, we risk underestimating the extent of changes that have occurred as a result of trawling activities. We examined witness testimonies recorded during two Royal Commissions of Enquiry (1863–66 and 1883–85). These enquiries interviewed hundreds of fishers about the early effects of sail trawling and the changes they were witnessing to fish stocks, habitats and fishing practises during this time. We converted all quantitative statements of perceived change in fish stocks and fishing practices to relative change. Witnesses from the north‐east of England interviewed during 1863 revealed an average perceived decline in whitefish of 64% during their careers, which many blamed upon trawling. Between 1867 and 1892, trawl‐landing records from the same location suggest that this trajectory continued, with fish availability declining by 66% during the period. Fishers adapted to these declines by increasing distances travelled to fishing grounds and increasing gear size and quantity. However, inshore declines continued and by the early 1880s even trawl owners were calling for closures of territorial waters to trawling in order to protect fish nursery and spawning grounds. Until now, these testimonies have been largely forgotten, yet they reveal that alterations to near‐shore habitats as a result of trawling began long before official data collection was initiated.  相似文献   
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