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71.
72.
湿地鸟类在能量转换和维护生态系统的稳定性方面起着举足轻重的作用,同时也是监测、评价湿地生态环境极其敏感的指标。本文总结了环境因子对湿地鸟类多样性的影响,对湿地鸟类多样性的研究提出展望,为更好地保护湿地鸟类资源及生态环境提供科学依据。  相似文献   
73.
Current feeder space recommendations in laying hen welfare guidelines are inconsistent among and within countries. One determining criterion forming the recommendations (e.g. 12.0 cm/hen for the EU guideline) is that all birds can feed simultaneously. However, if there are other resources in the environment, as in enriched colony housing (ECH), it is unknown whether group-housed hens will choose to feed simultaneously. This study assesses the impact of feeder space on feeding behavior of 60 laying hens (W-36) in ECH using a ultra-high frequency radio-frequency identification-based tracking system. The feeder spaces investigated were 12.0, 9.5, 8.5 and 6.5 cm/hen, achieved by blocking portions of the overall feeder access to keep hens at the same stocking density. Each feeder space treatment, randomly assigned over the course of the experiment, lasted for 7 consecutive days. Feeding behaviors were characterized as daily time spent at the feeder (TS, min/hen-day), daily frequency of visits to the feeder (FV, #/hen-day), and maximum or average percentage of hens feeding simultaneously (MPB, APB, %). Group-average daily feed intake (FI, g/hen-day), water use (WU, g/hen-day), and hen-day egg production (HDEP, %) were also measured. The results revealed that at 12.0 cm/hen, where unoccupied feeder space was present, a maximum of 59.0±1.4% (average of 31.7±0.3%) hens fed simultaneously. No significant differences were detected among 12.0, 9.5 and 8.5 cm/hen in TS (293±10, 286±10 and 281±10 min/hen-day) and MPB (59.0±1.4, 57.3±1.4 and 53.3±1.4%) (P>0.05). The outcome of no significant differences also held true between 12.0 and 9.5 cm/hen in APB (31.7±0.3 v. 30.8±0.3%) and between 9.5 and 8.5 cm/hen in all response variables measured (P>0.05). However, there were significant differences in APB between 6.5 cm/hen and all other treatments; in TS and FV between 6.5 and 9.5 cm/hen; and in MPB between 6.5 and 12 cm/hen (P<0.05). Considerable inter-hen variability was observed in TS (CV varying from 28.0% to 32.1%) and FV (CV varying from 26.5% to 27.8%). All the feeder spaces tested showed no significant impact on FI, WU or HDEP (P>0.05). The results revealed that synchronous feeding of hens in the ECH did not increase with increasing feeder space. However, it is worth noting that lower feeder space may lead to aggression or frustration which was not quantified in the current study.  相似文献   
74.
BackgroundMendelian randomization (MR) analyses have been increasingly used to seek evidence of causal associations. This systematic review aims at characterizing and evaluating the reporting of MR analyses in oncological studies.MethodsThe PubMed database was searched to identify MR cancer studies until December 31, 2017. Two of the authors independently selected and evaluated reporting quality of the studies. Reporting quality in MR studies before 2016 and in 2016/17 was compared.ResultsCancer studies with MR analyses in 2016 and 2017 accounted for 55.8% of the total number of studies identified. In the 77 eligible articles, 39 (50.6%) did not report subjects’ characteristics, 53 (68.8%) did not conduct power estimation, 40 (51.9%) did not state all of the first three MR assumptions (i.e., genetic instrument is associated with exposure, is not associated with confounders, and acts on outcome only through exposure), and 31 (40.3%) did not exclude SNPs that diverged from Hardy-Weinberg equilibrium. More studies estimated power in 2016/2017 than before 2016 (p = 0.028).ConclusionsSome MR cancer studies did not sufficiently report essential information, posing obstacles for critical appraisal. This study proposes for MR analysis a guideline/checklist for future publications in cancer and other biomedical research.  相似文献   
75.
Data Monitoring Committees (DMCs) are an integral part of clinical drug development. Their use has evolved along with changing study designs and regulatory expectations, which has associated statistical and ethical implications. Although there is guidance from the different regulatory agencies, there are opportunities to bring more consistency to address practical issues of establishing and operating a DMC. Challenging issues include defining the scope of DMC decisions, the regulatory requirements and expectations, the perceived independence of DMCs, the specific focus primarily on safety, etc. Wider use of adaptive clinical trial designs in recent years introduce additional challenges in terms of trial governance and the complexity of DMC activities. A panel comprised of clinical and statistical experts from across academia, industry, and regulatory agencies shared their experience and thoughts on the importance of these aspects and offered perspectives on the future of the DMCs. This paper documents the thinking from the panel session at the CEN‐ISBS conference held in Vienna, Austria, 2017.  相似文献   
76.
穿山甲是一种常用作传统中药的珍稀动物,由于人为的滥捕,穿山甲已成为一种濒危动物.开展穿山甲的人工饲养,扩大物种繁殖和保护,已成为保护穿山甲资源的有效途径.本文通过对穿山甲生活习性和人工繁养的多年研究,总结制定出一整套优质高产养殖技术规范化操作规程:场地的选择与建造、种苗来源、饲料调配、饲养管理、日常管理、疾病防治和出栏时间等,以利于进一步快速有效地扩大穿山甲资源.  相似文献   
77.
We report on a global survey of diagnosing mental health professionals, primarily psychiatrists, conducted as a part of the development of the ICD‐11 mental and behavioural disorders classification. The survey assessed these professionals' use of various components of the ICD‐10 and the DSM, their attitudes concerning the utility of these systems, and usage of “residual” (i.e., “other” or “unspecified”) categories. In previous surveys, most mental health professionals reported they often use a formal classification system in everyday clinical work, but very little is known about precisely how they are using those systems. For example, it has been suggested that most clinicians employ only the diagnostic labels or codes from the ICD‐10 in order to meet administrative requirements. The present survey was conducted with clinicians who were members of the Global Clinical Practice Network (GCPN), established by the World Health Organization as a tool for global participation in ICD‐11 field studies. A total of 1,764 GCPN members from 92 countries completed the survey, with 1,335 answering the questions with reference to the ICD‐10 and 429 to the DSM (DSM‐IV, DSM‐IV‐TR or DSM‐5). The most frequent reported use of the classification systems was for administrative or billing purposes, with 68.1% reporting often or routinely using them for that purpose. A bit more than half (57.4%) of respondents reported often or routinely going through diagnostic guidelines or criteria systematically to determine whether they apply to individual patients. Although ICD‐10 users were more likely than DSM‐5 users to utilize the classification for administrative purposes, other differences were either slight or not significant. Both classifications were rated to be most useful for assigning a diagnosis, communicating with other health care professionals and teaching, and least useful for treatment selection and determining prognosis. ICD‐10 was rated more useful than DSM‐5 for administrative purposes. A majority of clinicians reported using “residual” categories at least sometimes, with around 12% of ICD‐10 users and 19% of DSM users employing them often or routinely, most commonly for clinical presentations that do not conform to a specific diagnostic category or when there is insufficient information to make a more specific diagnosis. These results provide the most comprehensive available information about the use of diagnostic classifications of mental disorders in ordinary clinical practice.  相似文献   
78.
The termination of the EU milk quota system on April 1, 2015 is leading to an increase in manure production in the Netherlands. Rather than focus on the quality of water and nature, of which at least the water quality has strongly improved during the last decades, discussions appear to center on strengthening proxy measures that are already being used and which are only remotely related to the quality issue. The quality of water and nature is determined for ground- and surface water by first measuring their N and P content and for nature areas the N deposition. When these values are higher than threshold values determined by ecologists, quality is inadequate and measures are needed. When values are lower, quality is adequate. Three basic problems need to be addressed: (i) threshold values are in practice considered to be permanent while they should be dynamic reflecting a learning process when comparing measurements of N and P values on the one hand and a simultaneous ecological characterization on the other. This requires more cooperation between soil scientists, hydrologists and ecologists. Dynamic characterization may well lead to locally different threshold values. (ii) many measurements of water quality are being made but hardly any measurements of N deposition on nature areas. Such measurements are needed to allow judgements as to the effect of agricultural practices on nature quality. (iii) The necessary further improvement in water and nature quality, as far as it is affected by agricultural practices, can only be achieved when farmers are fully committed and engaged. The current top-down regulations with a “command-and-control” character, while effective in the 1990s, cannot serve this purpose in the information age, the more so since farmers are increasingly well educated and ask too many questions that are not being answered. The suggestion is made to change the generic character of the legislation (“one size fits all”) to a system where “tailor made” management systems are designed for individual farms,considering environmental conditions in the area where the farm occurs. Researchers and farmers can work together in a joint-learning mode to develop such designs that can be recognized by certificates with a legal status. In any case, the proportionality principle needs to be considered assuring that the severity of measures taken are in balance with societal effects.  相似文献   
79.
80.
泰山白首乌生物学特性及繁育技术   总被引:1,自引:0,他引:1  
泰山白首乌为萝摩科植物耳叶牛皮消 (CynanchumauriculatumRoyleexWight)的块根 ,药用或生产淀粉食用。在海拔 70 0米以上泰山阴坡 ,少有分布 ,现处于野生状态 ,为开发泰山白首乌这一珍贵植物资源。本文主要介绍了该生物学特性和繁育技术。  相似文献   
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