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Roy Greenhalgh J. David Miller Gordon A. Neish H. Bruno Schiefer 《Applied microbiology》1985,50(2):550-552
The isolation and characterization of 10 isolates of six Fusarium spp. from plant and soil samples collected in Southeast Asia is reported. The ability of these isolates to produce trichothecenes both in liquid cultures (CZ, GYEP, and MYRO) and on rice was assessed, and their toxigenic potential was examined by skin assay and gavage studies with culture filtrates. Although culture filtrates of all the isolates caused minor damage to test animals, only that of F. equiseti DAOM 189762 produced trichothecenes. 相似文献
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These studies were designed to evaluate the ability of the zona-free hamster ova bioassay to detect differences in fertility of boar sperm. In the first study, sperm from two previously infertile boars were compared to sperm from seven previously fertile boars. The percentage of zona-free hamster ova penetrated by sperm from the previously infertile boars was significantly lower than the percentage of ova penetrated by sperm from previously fertile boars (18% of ova penetrated vs. 83%, P < .001). In the 14 ejaculates from the previously infertile boars that had ejaculate motilities of 50% or greater, the percentage of zona-free hamster ova penetrated continued to be lower than in ejaculates from the fertile boars. One of the two previously infertile boars consistently had a normal semen analysis. The only two observed manifestations of his reduced fertility were his zero conception rate and the limited ability of his sperm to penetrate zona-free hamster ova. In the second study, females were inseminated with equal numbers of sperm from two previously fertile males and the paternity of offspring determined at birth. The experiment was replicated with four combinations of six boars. A high correlation was observed between the percentage of offspring sired and the ability to penetrate zona-free hamster ova (R = .89). Neither morphology nor the ability of the sperm to undergo an acrosome reaction during in vitro incubation was correlated with fertility in the competitive mating situation. These results suggest the zona-free hamster ova bioassay can improve the in vitro fertility assessment of fresh boar semen. 相似文献
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The fall in ankle systolic pressure after exercise serves as an objective indicator of the severity of haemodynamically important peripheral arterial disease. Twenty-six patients were studied to establish the effects of different work loads on the pressure response and to develop a test to standardise these effects. The patients walked for one or two minutes at 4 km/h and one or two minutes at 6 km/h, and the fall in pressure was the same when measured immediately after exercise. The time taken for the pressure to return to the pre-exercise value varied. As the fall in pressure occurs after only one minute of exercise at 4 km/h on a 10% slope, this might be adopted as a standard test. It is acceptable to the patient, since claudication, angina, and shortness of breath rarely occur. It is sensitive enough to detect mild or asymptomatic disease and is useful in following up patients. 相似文献
6.
- Freshwater conservation is vital to the maintenance of global biodiversity. Ponds are a critical, yet often under‐recognized, part of this, contributing to overall ecosystem functioning and diversity. They provide habitats for a range of aquatic, terrestrial, and amphibious life, often including rare and declining species.
- Effective, rapid, and accessible survey methods are needed to enable evidence‐based conservation action, but freshwater taxa are often viewed as “difficult”—and few specialist surveyors are available. Datasets on ponds are therefore limited in their spatiotemporal coverage.
- With the advent of new recording technologies, acoustic survey methods are becoming increasingly available to researchers, citizen scientists, and conservation practitioners. They can be an effective and noninvasive approach for gathering data on target species, assemblages, and environmental variables. However, freshwater applications are lagging behind those in terrestrial and marine spheres, and as an emergent method, research studies have employed a multitude of different sampling protocols.
- We propose the Pond Acoustic Sampling Scheme (PASS), a simple protocol to allow a standardized minimal sample to be collected rapidly from small waterbodies, alongside environmental and methodological metadata. This sampling scheme can be incorporated into a variety of survey designs and is intended to allow access to a wide range of participants, without requiring complicated or prohibitively expensive equipment.
- Adoption of this sampling protocol would enable consistent sound recordings to be gathered by researchers and conservation organizations, and allow the development of landscape‐scale surveys, data sharing, and collaboration within an expanding freshwater ecoacoustic community—rather than individual approaches that produce incompatible datasets. The compilation of standardized data would improve the prospects for effective research into the soundscapes of small waterbodies and aid freshwater conservation efforts.
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J. K. Hawkey I. S. L. Loudon G. P. Greenhalgh G. T. Bungay 《BMJ (Clinical research ed.)》1971,4(5788):667-670
A new concept for filing medical records in general practice is described, based on an A4-size folder; in experimental use in 40 practices doctors were generally in favour of the new system. 相似文献
9.
Twelve mature wethers were used in an experiment of change-over design to determine the effect of complete diet feeding on intake and digestibility of diets based on alkalitreated straw and a concentrate containing rolled barley and extracted soya bean meal. Two diets were used: D1 with a 50:50, and D2 with a 75:25 ratio of straw:concentrates on a dry matter basis. The straw and concentrates of each diet were given either separately (S) or as a complete diet (C). Complete diets gave a slightly, but not significantly higher intake (C, 86.5) and S, 82.5 g dry matter /kg W0.75 per day). The separate method gave a significantly higher digestibility coefficient for dry matter (C, 62.2 and S, 65.5; P < 0.05) and for crude fibre (C, 57.2 and S, 62.5; P < 0.01). Water intake increased by 42.7 ml g?1 Na derived from NaOH. There were no significant interactions between the method of feeding and the type of diet in intake and digestibility of the diets or in the intake of water. 相似文献
10.
Studies of hepatitis C virus (HCV) infection amongst injecting drug users (IDUs) have suggested that this population can be separated into two risk groups (naive and experienced) with different injecting risk behaviours. Understanding the differences between these two groups and how they interact could lead to a better allocation of prevention measures designed to reduce the burden of HCV in this population. In this paper we develop a deterministic, compartmental mathematical model for the spread of HCV in an IDU population that has been separated into two groups (naive and experienced) by time since onset of injection. We will first describe the model. After deriving the system of governing equations, we will examine the basic reproductive number $R_0$ , the existence and uniqueness of equilibrium solutions and the global stability of the disease free equilibrium (DFE) solution. The model behaviour is determined by the basic reproductive number, with $R_0=1$ a critical threshold for endemic HCV prevalence. We will show that when $R_0\le 1$ , and HCV is initially present in the population, the system will tend towards the globally asymptotically stable DFE where HCV has been eliminated from the population. We also show that when $R_0>1$ there exists a unique non-zero equilibrium solution. Then we estimate the value of $R_0$ from epidemiological data for Glasgow and verify our theoretical results using simulations with realistic parameter values. The numerical results suggest that if $R_0>1$ and the disease is initially present then the system will tend to the unique endemic equilibrium. 相似文献