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This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia).However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation.In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.  相似文献   
3.
郑炜  陈军正  吴潇雪  陈翔  夏鑫 《软件学报》2020,31(5):1294-1313
软件安全问题的发生在大多数情况下会造成非常严重的后果,及早发现安全问题,是预防安全事故的关键手段之一.安全缺陷报告预测可以辅助开发人员及早发现被测软件中潜藏的安全缺陷,从而尽早得以修复.然而,由于安全缺陷在实际项目中的数量较少,而且特征复杂(即安全缺陷类型繁多,不同类型安全缺陷特征差异性较大),这使得手工提取特征相对困难,并随后造成传统机器学习分类算法在安全缺陷报告预测性能方面存在一定的瓶颈.针对该问题,提出基于深度学习的安全缺陷报告预测方法,采用深度文本挖掘模型TextCNN和TextRNN构建安全缺陷报告预测模型;针对安全缺陷报告文本特征,使用skip-grams方式构建词嵌入矩阵,并借助注意力机制对TextRNN模型进行优化.所构建的模型在5个不同规模的安全缺陷报告数据集上展开了大规模实证研究,实证结果表明:深度学习模型在80%的实验案例中都要优于传统机器学习分类算法,性能指标F1-score平均可提升0.258,在最好的情况下甚至可以提升0.535.除此之外,针对安全缺陷报告数据集存在的类不均衡问题,对不同采样方法进行了实证研究,并对结果进行了分析.  相似文献   
4.
Reporting of information is crucial to enable backward and forward tracing of food along the chain, which is of main importance in case of non-compliance with legal obligations on food safety. Thus, food business operators in the European Union (EU) must enable tracing of any foodstuff one step forward and one step back. However, flux of information relevant for traceability and food safety can be a challenge in the supply chains of dried culinary herbs and spices.Results of a survey among herb/spice businesses – either located within the EU or exporting dried herbs/spices to the EU – showed the widespread use of electronic systems for recording and processing of traceability/food safety data. However, automated capture of transaction data and automated read-out/processing of reported data were rare. The survey indicates that besides electronic documents, typed paper documents are often exchanged between businesses. For data delivery along the chain, paper documents filled in by hand are still used – even in the EU or upon import to the EU. The document type as well as the forms varied, particularly in case of incoming herbs/spices. The forms used for reporting by the survey participants or by their suppliers covered mostly individual/company-specific forms. Standardised forms provided by herb/spice associations were rarely shared between these businesses. The extent of reporting of traceability data upon import to the EU and within the EU appears to be sufficient. Some additional traceability data that promote product tracing, such as the country of harvest, were frequently reported. Same was true for information on food safety hazards.  相似文献   
5.
房地产开发商做拟建项目建设费用的估算,主要目的之一是为项目的实施筹措资金。估算费用的首要功能就是控制项目建设成本开支。本文结合实际,从估算费用的资料收集、费用计算以及报审批准几个方面做了论证,以期达到一方面为项目的顺利实施、估算金额留有余地;另一方面,估算费用额计算有根有据,不高估冒算的目的。  相似文献   
6.
The development of the scientific theory on the stability of vaulted structures was driven mainly during the 18th century based on applying the laws of Mechanics and the knowledge of the properties of materials. In the specific case of structures such as domes, the development of the theory is closely related to the theory of arches and vaults. Still, the main contributions are made in technical reports on the construction, stability, and repair of domes, such as the dome of Saint Peter's in Rome and Sainte-Geneviève or Pantheon in Paris. This article, therefore, analyses the relationship between theory and practice and the development achieved in the specific subject of masonry domes during the 18th century from the point of view of the Limit Analysis of Masonry Structures. In a more general sense, the objective of this research is to study in greater depth the theory of Limit Analysis itself, that is, to learn from the work carried out in the 18th century by mathematicians, architects, and engineers, who, although unaware of the existence of the theoretical framework of Limit Analysis as such, moved within it.  相似文献   
7.
李令文 《甘肃冶金》2012,34(6):131-133
随着控制系统现场总线的大量应用,通讯网络稳定性直接关系到控制系统工作的可靠性。本文透过一个具体的自控系统总线设备通讯故障案例,尝试通过实验的方法进行分析总结,力求通过现象探寻问题的本质,为类似问题提供一个解决思路。  相似文献   
8.
对CPR1000反应堆冷却剂泵施工中的典型案例处理和方案改进等方面进行探讨和总结,对后续CPR1000项目主泵施工提出一些建议.  相似文献   
9.
康国柱  戴维 《铁合金》2010,41(5):43-48
锰铁厂的扬尘点很多,大多数除尘点采用布袋除尘器收尘。布袋除尘器是一项成熟的技术,经过净化的废气含尘浓度小于50 mg/m~3,完全符合国家排放标准要求;但由于现场条件的不同和设计的差异,许多锰铁厂的环境仍然不能达标。为保护环境,保护职工身体健康,文中介绍了先进的工程技术和综合管理措施,做到清洁生产。  相似文献   
10.
The authors obtained self- and observer reports of personality from pairs of well-acquainted college students. Consistent with previous findings, results of Study 1 showed strong cross-source agreement for all 6 HEXACO personality factors (rs ≈ .55). In addition, the authors found modest levels of similarity (r ≈ .25) between dyad members' self-reports on each of 2 dimensions, Honesty-Humility and Openness to Experience. For these same 2 factors, dyad members' self-reports were correlated with their observer reports of the other dyad member (r ≈ .40), thus indicating moderately high assumed similarity. In Study 2, Honesty-Humility and Openness to Experience were the 2 personality factors most strongly associated with the 2 major dimensions of personal values, which also showed substantial assumed similarity. In Study 3, assumed similarity was considerably stronger for close friends than for nonfriend acquaintances. Results suggest that assumed similarity for Honesty-Humility and Openness to Experience reflects a tendency to overestimate one's similarity to persons with whom one has a close relationship, but only on those personality characteristics whose relevance to values gives them central importance to one's identity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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