Marteiliosis in mussels: a rare disease?

Among 1280 cultured and wild adult Mediterranean mussels, Mytilus galloprovincialis, collected over a 1 ‐ year surveillance period from the Slovene Adriatic Sea, 0.3% were histologically positive for the presence of Marteilia spp. The infection was concentrated in winter. Employing the molecular methods of PCR, cloning, DNA restriction and sequencing, only Marteilia refringens type M was detected in all the infected mussels. Although all life‐cycle stages of M. refringens severely infected digestive glands, only sporadic disruption of epithelial cells of digestive tubules and focal destruction of digestive tubules were observed in the infected mussels. This was the first detection of M. refringens in M. galloprovincialis from the Slovene Adriatic Sea with the lowest prevalence reported to date. In addition, our results highlight the need for sequencing to complement the established PCR‐RFLP analysis for correct parasite typing.     

Does post‐grazing sward height influence sward characteristics,seasonal herbage dry‐matter production and herbage quality?

Extending the grazing season through the production and utilization of high‐quality forage is a key objective in grassland‐based dairy production systems. Grazing swards to a low post‐grazing sward height (PGSH) is a strategy for improving grass utilization. A grazing experiment conducted in Ireland investigated immediate and subsequent effects of PGSH on sward production, utilization and structural characteristics. Swards were grazed to 2·7 cm (severe; S1) or 3·5 cm (moderate; M1) from 10 February to 18 April 2010 (Period 1; P1). From 19 April, each P1 paddock was halved and grazed to either 3·8 cm (S2) or 4·8 cm (M2), until 30 October (Period 2; P2). The first grazing rotation was +7 d on S1 swards compared with M1 swards (45 d), due to greater herbage utilization (+0·22). Herbage production during P1 was not affected by PGSH but a severe PGSH during this period reduced subsequent herbage production: 13·9 (S1) vs. 15·5 t dry matter (DM) ha^?1 (M1) by the end of the study. Leaf proportion was increased (+0·10) on S2 swards compared with M2 swards, but M2 swards produced 1·2 t DM ha^?1 more herbage during P2. Despite the relatively lower level of sward utilization obtained from moderate grazing in P1 (3·5 cm) and P2 (4·5–5·0 cm), such levels of PGSH increased DM production while maintaining sward quality, compared with severe grazing (2·7 cm in P1 and 3·5–4·0 cm in P2).     

2018年我国东北局部草地螟重发

2018年我国内蒙古、黑龙江、吉林三省交界处草地螟突发高密度种群,导致年度发生面积和发生程度为近10年以来最高。2018年草地螟各世代的发生特点为越冬代成虫发生面积大、内蒙古、黑龙江蛾量高,1代幼虫在内蒙古中东部重发,1代成虫在内蒙古东北部和河北局部种群数量高,2代幼虫仅零星发生。分析了我国东北局部种群数量突增的原因,即越冬代成虫异地大量迁入,且重发区域空中风场和天气条件有利于成虫降落和产卵。     

伏旱高温期不同品种柑桔果面温度日变化

以温州蜜柑、脐橙和椪柑为材料,在重庆伏旱高温期间,选择晴天和阴天分别测定果实顶部和基部的温度日变化。结果表明：三个品种的果面温度为温州蜜柑＞脐橙＞椪柑;晴天树冠南面果实顶部日最高温一般出现在12:30~14:30;果实表面温度与气温和太阳辐射显著或极显著正相关,气温对果面升温有显著影响,但太阳辐射对果实持续高温甚至发生日灼有更重要作用。在气温38.3℃时,温州蜜柑果顶温度最高达55.2℃,脐橙次之54.1℃,椪柑最低50.2℃;日灼果比例也以温州蜜柑最高,脐橙次之,椪柑最低,说明高温季节果面温度不同是这3个品种日灼率不同的主要原因。     

两种水生植物对重富营养化水体修复效果研究

为了探索重富营养化水体的植物修复方法,在人工模拟条件下选取了两种水生植物伊乐藻(Elodea nuttallii)和黄花水龙(Jussiaea stipulacea Ohwi),采用漂浮生长方式对富营养化水体中养分的去除效果进行研究。结果表明:沉水植物伊乐藻在水面漂浮条件下可起到净化水体的作用,对总氮、氨态氮、硝态氮、总磷、COD、叶绿素a的去除率分别为62.9%,90.83%,53.90%,71.21%,43.33%,50.05%;漂浮植物黄花水龙对上述污染物的去除效果分别为93.56%,97.38%,99.44%,97.74%,52.49%,58.34%。变异分析表明,两者对这些养分的去除达到了显著水平(P<0.05)。黄花水龙对上述污染物的去除效果明显好于漂浮培养条件下的伊乐藻,适合重富营养化水体中养分的去除,而伊乐藻则在水质维持方面发挥更大作用。     

低温环境下热泵热风干燥藏药性能试验

为提升低温环境下藏药干燥特性,该研究提出回热、喷焓热泵干燥系统模式,并通过试验探究所设计系统持续运行的稳定性及能效特性,获取低温条件不同方式载物模式下热泵连续运行的特性及变化规律。研究结论如下：在冬季高原严寒大温差（30 ℃）下,回热型热泵系统换热器换热效率平均为13.58%。喷气增焓热泵系统（?13.39～16.69 ℃）最低制热系数COP（Coefficient of Performance, COP）比普通涡旋热泵系统（?11.4～18.3 ℃）提升了51.5%,COP平均提高16.9%,有效提高了低温下系统制热能效。物料摆放方式以及铺料厚度对干燥效果影响显著,当装载量为100%,码放高度20 cm时,物料成品表皮色泽金亮,干燥度均匀,单位能耗除湿量SMER（Specific Moisture Extraction Rate,SMER）大。与传统方式相比,对同等数量的物料,热泵干燥耗时仅为传统阴干方式的1/9,且成本降低1 160元/t,同时避免了环境的二次污染。研究结果表明回热、喷焓型热泵系统能满足低温工况下藏药材干燥所需的能量供给且能够稳定运行。     

设施蔬菜越冬期极端低温的分布及重现期特征——以关中、陕北地区为例

利用陕西陕北、关中地区1970～2010年66个县/区设施蔬菜越冬期资料建立了各站逐年极端最低气温、低于逐日最低气温5%阈值的气温和逐年出现严重冻害次数等3组资料的时间序列,分别对越冬期极端低温出现几率、强度进行了特征分析,利用耿贝尔分布方法建立了7个代表站年极端最低气温的分布模型及重现期预测。结果表明:1)对于严重冻害出现频次,延安东部的黄河沿岸地区在0.6～3.7次/年,陕北其它地区在4.3～18.7次/年,长武、旬邑和麟游渭北北部塬区在6.5～11.1次/年,关中其它地区在0.0～3.7次/年;2)低于逐日最低气温5%阈值的气温多年平均陕北地区、关中地区分别为-15.1～-19.9℃、-6.1～-8.7℃,严重冻害关中地区出现几率不足5%,陕北部分地区出现几率超过5%;3)陕北地区在不足2a的重现期,关中地区在8a的重现期会出现严重冻害,相同重现期关中地区冻害强度远低于陕北地区。     

广东矿区生态恢复案例分析及其恢复技术探讨

矿区的开采和利用引发了一系列的生态环境问题,矿区废弃后未进行及时恢复对环境造成的严重危害已引起广泛关注。文章对广东部分矿区进行生态恢复案例分析研究,并对广东矿区的生态恢复在技术方面提出建议。     

Seroprevalence of antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in household dogs in Japan

We investigated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among dogs in the Tokyo area via enzyme-linked immunosorbent assay (ELISA) using the spike protein as the target antigen. Plasma samples from 494 household dogs and blood-donor dogs were tested from July 2020 to January 2021. Of these samples, three showed optical densities that were higher than the mean plus two standard deviations of the mean of the negative-control optical densities (ODs). Of these three samples, only the sample with the highest OD by ELISA was confirmed positive by virus neutralization testing. The positive dog presented no SARS-CoV-2-related symptoms. The positivity rate of SARS-CoV-2 infections among dogs in the Tokyo area was approximately 0.2%.     

一例犬腹水病例的诊断与治疗

腹水是指在动物腹腔内充盈的液体处于非生理性存留的一种状态。液体可分为炎性渗出液和非炎性漏出液两种。腹水并不是一种独立的疾病,而是由其他病症引起的一种临床继发症状。腹水在临床上容易诊断通过视诊、触诊、叩诊结合腹腔穿刺实验可以综合诊,关键在于其病因难以诊断。本病例根据临床症状通过视诊、触诊、叩诊临床一般检查结合腹腔穿刺实验、血液常规检查、血液生化检查、血气检查、X光片检查、B 超检查、心电图检查结果判断是心源性腹水、稀血性腹水、瘀血性腹水、寄生虫还是中毒等引起的。然后采取对症对因治疗,去除病因。