镇江长江豚类省级自然保护区水域生态修复效果的监测与评价

自2006年以来,长江豚类极度濒危的生存状况得到广泛关注,在其自然保护区实施一系列生态修复工程,为镇江长江豚类省级自然保护区内的江豚提供良好的生存环境。于2015—2018年在和畅洲水域建设生态浮岛、人工鱼巢和放流底栖动物进行水域生态修复,对生态修复工程进行跟踪监测和效果评价。结果表明：生态浮岛的建设可提高区域内浮游植物和浮游动物的生物多样性和群落结构复杂程度;人工鱼巢对产黏性卵鱼类具有一定增殖效果,增殖种类主要为鲤、鲫、䱗和黄尾鲴;生态浮岛和人工鱼巢的建设对鱼类均有较好的聚集效果;底栖动物增殖放流显著增加了放流物种的丰度、生物量及保护区底栖动物群落生物量,增殖放流效果评价为中等。该自然保护区水域生态修复效果明显,为工程施工影响下水生生物保护区生态修复提供科学依据。     

文本挖掘下的话语认知与构建——以人工智能和5G领域白宫新闻文本为例

[目的/意义]政府新闻文本是政策文本的表达形式之一。对政府新闻文本进行挖掘分析,能直观的展现表面动态,揭示对话事件的立场及其背后关系,能对情报分析工作、中国新型智库的发展建设,提供有效的助力。[方法/过程]文章利用TextRank算法进行核心句提取,并结合批评话语分析理论框架来做评估,以语料驱动从关键句、关键词两个宏观角度讨论政府决策态度,以词性从话语策略的微观角度总结美国官方对人工智能和5G领域的话语认知形象。[结果/结论]通过分析可以看出,美国政府对于人工智能和5G领域的态度将持续保持在“政府引领下的美国需优先”这一局面,面对发展中国家的科技竞争,增加政府政策性文本的指导无疑是最好的对策建议。     

Modelling optimal timing and frequency of insecticide sprays for knockdown in preparation for other control measures

A modelling investigation was conducted into optimizing the number of sprays and inter-spray interval to reduce an insect population to a low level, for example, prior to pheromone trapping or the release of sterile males. The model population was age-structured and density-dependent. If spray mortality is 100% for each spray, then the ideal spraying schedule is easily determined from the durations of the various life stages. For spray mortality of less than 100%, a simulation was used to determine optimal spraying schedules. Relative length of the larval period, fertility rate and age to first oviposition were found to be the most important biotic parameters for this determination. Their importance is magnified as spray mortality decreases. The stage targeted by sprays and the percent mortality caused by each spray are also important in determining the required number of sprays. Using medfly (Ceratitis capitata Wiedmann) biotic parameters as an example when the spray targets adults, it appeared that neither the stage at which density-dependent mortality takes effect, nor the form of the adult survivorship curve are important in determining the optimal spray schedule.     

Evidence of cormorant‐induced mortality,disparate migration strategies and repeatable circadian rhythm in the endangered North Sea houting (Coregonus oxyrinchus): A telemetry study mapping the postspawning migration

Life history theory predicts a trade‐off between migration and residency where migration is favoured when it infers elevated fitness. Although migration to more favourable environments may offer higher growth rates, migrants often experience increased mortality due to predation. Here, we investigated mortality and migration behaviour of the North Sea houting (Coregonus oxyrinchus), an anadromous salmonid endemic to the Wadden Sea. We used acoustic telemetry to map the migration of the only remaining indigenous population by applying stationary hydrophones combined with manual tracking. Data suggested a total mortality of 26%, with 30% of the total mortality attributed to predation by great cormorants (Phalacrocorax carbo sinensis), highlighting that North Sea houting conservation could be jeopardised by increased cormorant predation. Risk of cormorant predation was size‐dependent, with smaller fish suffering higher risk of predation. The study found North Sea houting to exhibit disparate migration strategies and identified a lentic area in the estuary as an important habitat. Two newly established artificial lakes within the river system significantly reduced the migration speeds, possibly indicating constrained navigation through the lakes. The migration into the Wadden Sea correlated with temperature perhaps indicating osmoregulatory constraints of sea entry. Unlike many salmonid species, migration occurred both day and night. Moreover, fish exhibited repeatable individual differences in diel activity patterns, suggesting that individuals differ consistently in their migratory activity throughout the 24‐hr period. Our study provides novel information on salmonid migration, which is crucial for the development of science‐based conservation strategies.     

A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

龙竹高产栽培技术

龙竹为大型丛生竹，具有重要的经济价值和生态价值。文章试验研究了育苗方式、坡向、肥料种类以及造林整地方式对龙竹生长的影响。结果表明：与其他育苗方式相比，龙竹组培苗造林竹株生长好，竹材产量高；龙竹适宜栽植于阴坡，采用全面整地法，在造林后的前4年每年施用适量的氮磷钾复合肥，可培育出高产的龙竹林。     

野生樱桃资源在甜樱桃人工授粉中的应用探讨

以3种野生樱桃资源为供试材料,比较了花粉烘制方式和贮藏温度对供试材料花粉萌芽率的影响,评价了供试材料花粉对甜樱桃品种座果率的影响。结果表明：常温干燥皿烘制花粉萌发率显著高于培养箱烘制；水+10mg/L硼酸+20%蔗糖为测定供试材料花粉活力的适宜培养基；毛樱桃、中国樱桃、‘黄蜜’花粉在4℃冷藏30天的萌发率均高于40%；毛樱桃、中国樱桃和山樱桃花粉与3个甜樱桃品种的异花授粉平均坐果率可达到40%。作者认为,供试野生樱桃资源的花粉萌发和贮藏特性,以及与甜樱桃品种的异花授粉亲和性与供试甜樱桃品种花粉类似,在甜樱桃人工授粉中具有较大的应用价值。     

混播比例对三江源人工草地植被和土壤养分特征的影响

建植混播人工草地是修复三江源黑土滩退化草地的有效措施，但不同混播比例下植被和土壤养分特征的变化尚不明确。以垂穗披碱草、中华羊茅和青海草地早熟禾分别按1∶1∶1（M₄），2∶1∶1（M₅），1∶2∶1（M₆），1∶1∶2（M₇），2∶2∶1（M₈），2∶1∶2（M₉）和1∶2∶2（M₁₀）建植混播人工草地，并以各组分单播为对照，研究生产力、物种多样性、超产效应、多样性净效应（包括互补效应和选择效应）和土壤养分特征的变化，并采用多准则决策模型-TOPSIS进行综合评价，以筛选最佳混播比例，以期为三江源退化草地生态修复提供科学依据。结果表明：混播处理地上生物量显著高于中华羊茅和青海草地早熟禾单播的生物量，但显著低于垂穗披碱草单播处理，混播处理地上生物量在M₅、M₈、M₉和M₁₀处理较高。而地下生物量在混播处理间无显著差异。混播处理中，仅M₅、M₈、M₉和M₁₀处理存在超产，达40.4~71.1 g·m^-2。M₄和M₆处理的多样性净效应均小于0，说明由于物种竞争导致群落减产。而M₇~M₁₀混播处理的多样性净效应均大于0，说明物种生态位的互补使得群落高产。M₈和M₉处理中互补效应和选择效应共同主导了超产效应，而M₅和M₁₀处理中主要由互补作用主导超产效应。表层土壤的有机质、全氮、全磷、速效磷和速效钾含量在M₆、M₇和M₁₀混播处理中较高。TOPSIS模型综合评价表明，M₁₀混播处理不但可保持较高的生产力，还可显著提高土壤的养分含量，是三江源区人工草地建植的理想混播比例。     

禾田稻2号选育技术报告

禾田稻2号(代号松辽628)是公主岭市松辽农业科学研究所以白粳1为母本、长白19为父本,双亲配组,有性杂交,后代材料经世代选拔培育,系谱法、穿梭育种,最终选育而成的水稻新品种。该品种株高适中、株型紧凑、分蘖力较强,成穗率好,结实率高,中感稻瘟病,米质好,产量高,综合性状优良,2020年通过内蒙古自治区农作物品种审定委员会审定,适宜在内蒙古中晚熟稻区等地种植。