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601.
Abstract: Concentrating tourism activities can be an effective way to closely manage high‐use parks and minimize the extent of the effects of visitors on plants and animals, although considerable investment in permanent tourism facilities may be required. On coral reefs, a variety of human‐related disturbances have been associated with elevated levels of coral disease, but the effects of reef‐based tourist facilities (e.g., permanent offshore visitor platforms) on coral health have not been assessed. In partnership with reef managers and the tourism industry, we tested the effectiveness of concentrating tourism activities as a strategy for managing tourism on coral reefs. We compared prevalence of brown band disease, white syndromes, black band disease, skeletal eroding band, and growth anomalies among reefs with and without permanent tourism platforms within the Great Barrier Reef Marine Park. Coral diseases were 15 times more prevalent at reefs with offshore tourism platforms than at nearby reefs without platforms. The maximum prevalence and maximum number of cases of each disease type were recorded at reefs with permanently moored tourism platforms. Diseases affected 10 coral genera from 7 families at reefs with platforms and 4 coral genera from 3 families at reefs without platforms. The greatest number of disease cases occurred within the spatially dominant acroporid corals, which exhibited 18‐fold greater disease prevalence at reefs with platforms than at reefs without platforms. Neither the percent cover of acroporids nor overall coral cover differed significantly between reefs with and without platforms, which suggests that neither factor was responsible for the elevated levels of disease. Identifying how tourism activities and platforms facilitate coral disease in marine parks will help ensure ongoing conservation of coral assemblages and tourism.  相似文献   
602.
尖孢镰刀菌致病相关因子及其分子生物学研究进展   总被引:2,自引:0,他引:2  
由致病性尖孢镰刀菌(Fusarium oxysporum)侵染引起的植物枯萎病是一种世界性的土传真菌病害,对农业生产造成了巨大经济损失.研究表明,尖孢镰刀菌的致病与多种致病因子相关,包括信号传导系统(环腺苷酸单磷酸-蛋白激酶A和促分裂素原活化蛋白激酶信号途径)、细胞壁降解酶(木聚糖酶、果胶酶、果胶裂解酶、细胞毒素、纤维素酶、半纤维素酶和木质素降解酶等)、克服植物防御响应系统(降解抗真菌化合物和破坏植物细胞壁的化学修饰)以及其它(细胞毒素和过氧化物酶)等.此外对今后的研究工作提出展望.参26  相似文献   
603.
研究了在硫酸介质中、溴化钾催化下 ,碘酸根氧化酸性铬蓝K褪色的最佳条件。其最大吸收波长λmax为 5 2 0nm ,表观摩尔吸光系数为 1 .1× 1 0 4 L·mol- 1·cm- 1,碘浓度在 0~ 3 .6mg/L内呈线性关系。方法用于测定加碘食盐中的碘 ,结果令人满意  相似文献   
604.
Mitochondrial acetoacetyl-coenzyme A (CoA) thiolase deficiency is an organic aciduria which affects isoleucine and ketone body catabolism. GK16 (the index patient) was affected with this disorder and previous studies had revealed that GK16 was a compound heterozygote with IVS8(+1) gt to tt and A301P mutations. In a subsequent pregnancy, prenatal diagnosis was performed and the fetus's amniocytes were analysed by the polymerase chain reaction (PCR) followed by the heteroduplex detection method on a Mutation Detection Enhancement gel. The fetus was identified as a carrier of the IVS8(+1) mutation. We confirmed the diagnosis by immunoblot analysis of extracted amniocytes and gene analysis with blood filter paper after delivery. This is the first report of prenatal diagnosis of this disorder at the gene level.  相似文献   
605.
Bovine spongiform encephalopathy (BSE) has been documented in 28 countries and adversely affected farmers and rural communities around the world. Our study examines the impacts of and adaptive responses of producers to BSE in western Canada. Moreover, it explores the role that holistic management (HM), and its combined focus on environmental, social, and economic sustainability, might play in mitigating the effects of BSE. One survey was sent to 835 HM producers and another to 9,740 producers across Manitoba, Saskatchewan, and Alberta. The disease, and concomitant climate change and low commodity prices, had devastating impacts on both groups. Yet, HM producers were much more optimistic about their ability to adapt to BSE and the future of agriculture than their non-HM counterparts. Social networks, namely HM clubs and the larger HM community, enabled these producers to mitigate the impacts of BSE. Agronomic responses, especially those associated with rotational grazing and increases in on-farm biodiversity were also important. That HM has been such an effective adaptive response to BSE indicates the importance of this and other grassroots responses to rural crises, whether they be associated with zoonotic diseases or indeed environmental change as a whole.  相似文献   
606.
Seventeen patients were referred to our ultrasound unit because of fetal bradyarrhythmia (<100 bpm). Duration of pregnancy varied between 21 and 40 weeks. Bradyarrhythmia was diagnosed as atrioventricular block (n = 12), mild sinus bradycardia (n = 3), and irregular bradycardia (n = 2). The association with maternal collagen disease was 29 per cent and with cardiac structural defects 59 per cent. The overall mortality was 41 per cent. There were three abnormal karyotypes (17 per cent) and four cases of cardiac compromise (23 per cent). Prognosis depends on the nature of the bradyarrhythmia and recognition of associated pathology such as cardiac structural defects, abnormal karyotype and degree of cardiac compromise.  相似文献   
607.
Congenital heart disease (CHD) is one of the commonest prenatal diagnoses made on routine ultrasound screening. Overall, up to 33% of CHD are associated with fetal aneuploidy. However, some specific cardiac lesions have a significantly greater association with particular chromosomal abnormalities. The majority of fetuses with CHD and aneuploidy also have extra-cardiac anomalies and are best managed by a multidisciplinary team where the management and prognosis of the cardiac defect can be discussed in the context of the baby as a whole. It is therefore important for clinicians involved in the management of fetuses with CHD to be aware of the association of aneuploidy as well as the prognosis and management of these cases, so that they can appropriately counsel the parents. In this chapter, we review the frequency and types of aneuploidy associated with the commonly diagnosed CHD and discuss their management. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
608.
Disinfection by-products(DBPs) are a complex mixture of compounds unintentionally formed as a result of disinfection processes used to treat drinking water. Effects of long-term exposure to DBPs are mostly unknown and were the subject of recent epidemiological studies. However,most bioanalytical methods focus on a select few DBPs. In this study, a new comprehensive bioanalytical method has been developed that can quantify mixtures of organic halogenated compounds, including DBPs, in human urine as total organic chlorine(TOCl), total organic bromine(TOBr), and total organic iodine(TOI). The optimized method consists of urine dilution, adsorption to activated carbon, pyrolysis of activated carbon, absorption of gases in an aqueous solution, and halide analysis with ion chromatography and inductively coupled plasma-mass spectrometry. Spike recoveries for TOCl, TOBr, and TOI measurements ranged between 78% and 99%. Average TOCl, TOBr, and TOI concentrations in five urine samples from volunteers who consumed tap water were 1850, 82, and 21.0 μg/L as X~-, respectively.Volunteers who consumed spring water(control) had TOCl, TOBr, and TOI average concentrations in urine of 1090, 88, and 10.3 μg/L as X~-, respectively. TOCl and TOI in the urine samples from tap water consumers were higher than the control. However, TOBr was slightly lower in tap water urine samples compared to mineral water urine samples, indicating other sources of environmental exposure other than drinking water. A larger sample population that consumes tap water from different cities and mineral water is needed to determine TOCl, TOBr, and TOI exposure from drinking water.  相似文献   
609.
环境中碘与动物体内碘代谢关系的研究   总被引:2,自引:0,他引:2       下载免费PDF全文
环境中碘与动物体内碘代谢关系的研究张庆朝,孙存孝,杨景芝,曾勇庆,张万福,杨世钺,王慧(山东农业大学动物科技学院,泰安271018)关键词:碘,降水,饮用水,绵羊尿.碘是人类发现的第二个生物必需的微量元素,是甲状腺激素组成不可缺少的成分,它的生理功能...  相似文献   
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