Tentacular nature of the ‘column’ of the Cambrian diploblastic Xianguangia sinica

Unveiling the body architectures of Cambrian problematic fossils would provide novel insights into the radiation of metazoan body plans during the ‘Cambrian Explosion’ and the ancestral traits of major living animal clades. Xianguangia sinica, from the celebrated Chengjiang biota (518Ma), is a typical Cambrian problematicum with disputable body architecture, particularly about its ‘column’ part. The contradictory interpretations of the ‘column’ of X. sinica have led to at least three hypotheses regarding its affinity in the diploblastic clade. Here we depict the detailed anatomy of the ‘column’ based on new, exquisitely preserved material. The ‘column’ of X. sinica is formed by 18 longsword-shaped tentacle-sheath complexes that can either close or be in a flowering state. There is no partitioned cavity internally when the ‘column’ is closed, invalidating the homology with the true column of living sea anemones. Each tentacle tapers distally and includes a distal flexible portion at about one-fourth the length of the tentacle. The proximal portion is stiff, bearing a set of paired dark stains, and is enveloped by a single outer sheath. Pinnules carrying a row of large cilia are fringed on both sides along the whole length of the tentacles. The body plan of X. sinica is accordingly revised as consisting of a calyx and 18 unique tentacle-sheath complexes that radially surround the mouth. Our result corroborates previous observations that suggest a close relationship between Xianguangia, Daihua and Dinomischus, all of which are here formally assigned to the family Dinomischidae, a monophyletic clade recovered in our phylogenetic analyses. Xianguangia sinica likely employs cilia-bearing pinnate tentacles for sieving particle matter down to 21 mm, indicating that its nutrition source is suspended micro-planktonic organisms or other organic matter in the bottom water

护理学生临床实习前锐器伤预防的认知情况调查研究

Objective: To investigate the cognition of sharp injury prevention among nursing students before the clinical practice in order to provide a basis for corresponding measures and active measures. Methods: In July 2014, a total of 232 nursing students in 3 A grade Hospital of Guangzhou, from 30 colleges and universities of 8 provinces, were tested by self-made questionnaire in regard to sharp injury prevention knowledge. Results: The awareness rate of occupational exposure, occupational exposure prevention, Guideline for prevention and control for occupational exposure to bloodborne pathogen by National Health and Family Planning Commission 2009 was 28.94% and 13.71%, 1.01%; and the highest score of sharp instrument injury prevention knowledge was 22 points, the lowest score was 4 points, with an average of 15.92 ± 2.59 points. Sharp injury knowledge gained from school education accounts for 87.31%, but the students who have not received relevant education accounts for 3.05%. Conclusion: The overall situation of occupational exposures cognition is not optimistic, the master of sharp instrument injury prevention knowledge is not complete; and related curriculum in part of the schools is unreasonable, or receives poor effect. Some schools need to adjust the curriculum, strengthen the prevention knowledge of sharp injuries, occupational exposure to bloodborne pathogen. Hospitals need to strengthen pre-job training of nursing students and strengthen the clinical teaching work. Schools and hospitals need to jointly explore teaching mode for nursing students, so as to promote the students to master the sharp instrument injury prevention knowledge, the implementation of relevant measures of protection, and ensure the safety of students and patients. 目的  对护理学生临床实习前锐器伤预防的认知情况进行了解，以便为采取积极有效的应对措施提供依据。方法  采用自行编制问卷对2014年7月广州市某三甲医院来自全国8省30所高等院校的232名护理实习学生的一般资料和锐器伤认知情况进行调查并分析。结果  职业暴露、职业暴露后预防、国家卫计委2009《血源性病原体职业接触防护导则》知晓率为28.94%、13.71%、1.01%；锐器伤预防知识最高得分22分，最低得分4分，均数为（15.92±2.59）分。锐器伤知识来源于学校教育为87.31%，而未接受过相关教育者为3.05%。结论  研究对象对职业暴露认知总体情况不容乐观；锐器伤预防知识掌握不全；部分学校相关课程设置不合理或教育效果欠佳。部分学校需调整课程设置，加强锐器伤预防、血源性病原体职业接触防护等相关知识的教育，医院需强化护理实习生岗前培训，加强临床带教工作，学校与医院需探讨共同教导护理实习学生模式，从而促进学生掌握锐器伤预防相关知识，落实相关防护措施，保障患者和学生的安全

Early development of the Amur sleeper (Perccottus glenii, Dybowski, 1877): a remarkable invasive species in Eurasia

To investigate the ontogeny of Perccottus glenii, embryonic, larval and juvenile development of P. glenii were examined under captive condition. The fertilized eggs with numerous oil droplets were orange-pink in color, prolate spherical in shape and had average length of 3.32±0.14 mm and width of 1.24±0.04 mm. From fertilization to hatching, the ontogenesis of the fish spent more than 200 h, and the process of embryonic development was divided into 25 stages based on the morphological characteristics. The newly hatched larvae, with well-developed swim bladder and pectoral fins, measured 5.07±0.18mm in total length. Initial feeding occurred at day 2 after hatching (AH) and the complete absorption of yolk sphere was observed 3 days after hatching. At day 40 AH, scales and vertical pigment were found to be appear. Scales covered the entire body and all fins were well developed 70 days AH, at which time the juveniles reached the young stage with a total length (TL) of 24.74±4.28 mm. At day 140 AH, The fry with a TL of 29.57±4.65 mm, were morphologically similar to the adults except for size