长江口日本鳗鲡苗的时空分布与捕捞生产现状

为掌握长江口日本鳗鲡的苗汛特征与捕捞生产现状,于2017—2020年在长江口开展了定点监测和走访调查,分析了长江口鳗苗的汛期规律、捕捞努力量及捕捞产量和产值。研究发现,长江口鳗苗旺发期为2-4月,主要捕捞区域分布在东旺沙、佘山岛和南汇嘴附近水域。长江口鳗苗捕捞努力量呈现下降趋势,有效网口面积从2017年的78.72万m²,下降到2020年的50.40万m²,下降了36%。长江口鳗苗汛期的单位捕捞努力量渔获量(CPUE)和总捕捞产量呈现波动变化趋势,2017和2020年较高,分别为(4 474±256)尾/100 m²和(5 220±1 063)尾/100 m²,2018和2019年较低,分别为(1 917±335)和(1 365±257)尾/100 m²。研究表明,长江口鳗苗生产值受到捕捞总产量影响,近4年来逐渐下降。建议进一步加强长江口鳗苗的资源监测和科学评估,指导规范鳗苗捕捞生产。     

Impact of cypermethrin on feeding behaviour and mortality of the spider Pardosa amentata in arenas with artificial 'vegetation'

Pesticides can modify invertebrate movement and feeding behaviour which could reduce predation in agroecosystems. Previous assays have exposed the spider Pardosa amentata (Clerck) to the synthetic pyrethroid cypermethrin and monitored prey items consumed in small containers (requiring very little movement to capture prey). The current study used larger arenas containing artificial 'vegetation' (a plastic analogue) to encourage spiders to hunt and capture prey. The period 24 h after exposure produced greatest variability in prey item consumption between treatments and was used to examine treatment effects. At this time, cypermethrin reduced prey consumption rates but these effects did not persist. Findings did not suggest that the presence of artificial vegetation in arenas modified prey consumption rates, which was consistent for individuals treated with cypermethrin and a control group. This is despite the majority of pesticide-treated individuals exhibiting both ataxia and paralysis of the hind legs (these effects persisting for a maximum of 3 and 6 days respectively). These findings were consistent for both sexes. Spider longevity under starvation conditions was not significantly reduced by cypermethrin exposure but overall females survived longer than males. The findings are discussed in the context of the arenas used and the ecology of this common predator.     

Who benefits from international tourism in small Pacific islands? Value capture in the hotel industry in Hawaii

There is a consensus among small Pacific islands that the extent to which they benefit from international tourism largely depends on how much of the value created by tourism remains in the local economy. This study examines how the value created in the hotel industry is distributed among the key stakeholders in a small Pacific island context. We used aggregated income statements of full-service and limited-service hotels from the STR Inc., a hotel industry data company, to calculate the value distribution among the key stakeholders in the hotel industry of a small Pacific island. We found that labour and owners captured most of the value created, whereas hotel management companies and franchisors captured a small share of the value. Our results suggest that tourism workers' ability to take united action and hence to negotiate higher wages will result in higher value capture by local labour and less value leaking out of the local economy. Our results also reveal that foreign ownership in the hotel industry is the single largest cause of economic leakages. The study has several implications for the tourism-based growth policies in small Pacific islands.     

一种适用于数据库应用系统的错误捕获机制

针对 Powerbuilder 所提供的出错控制机制在应用系统运行中交互性差的问题而提出的一种通用错误捕获机制.     

花粉中有机氯类农药串联固相萃取柱净化--气相色谱分析

本文旨在研究应用气相色谱一电子俘获检测器（GC—ECD）测定花粉中17种有机氯农药（OCPS）残留的检测方法。样品经丙酮／正己烷（V/V,1：1）浸泡过夜并超声提取后,研究了两种固相萃取柱（SPE）对样品的净化效果。结果表明：单独使用弗洛里硅土柱能获得满意的回收率,但基质干扰多。弗洛里硅土柱与石墨化碳柱联用能够取得更好的回收率和无色洗脱。在线性范围为0．005-5mg／L时,所有的有机氯农药都呈现很好的线性,相关系数均大于0．99。方法的检出限范围是0．81～1．99,定量限为2．64巧．62。在空白花粉样品中添加0．1mg／L、0．05mg／L的有机氯农药浓度水平下,茶花和油菜都得到了满意的回收率,平均回收率范围是60．6％-115．9％,相对标准偏差为1．2％-13．1％。实际样品的测定表明,污染严重的底泥在一定程度上影响了荷花粉的质量安全。     

Differential expression of cell cycle regulators p21, p27 and p53 in metastasizing canine mammary adenocarcinomas versus normal mammary glands

The cyclin dependent kinase inhibitors p21 and p27 are important regulators of cell cycle progression. To analyze their role in the malignant progression of canine mammary tumors expression levels of p27 and p21 and its major regulator p53 were compared in simple adenomas, adenocarcinomas of the mammary gland and lymph node metastases with normal mammary gland. Laser microdissection of tissue samples and real-time PCR were used for quantification of mRNA expression levels. p21 was overexpressed in adenocarcinomas, whereas adenomas and metastases expressed p21 more heterogeneously. Comparison of p21 expression in adenocarcinomas and their metastases revealed a significant decrease in expression in metastases. In contrast, p27 expression was reduced in the adenocarcinomas but heterogeneously expressed in adenomas and metastases. Taken together the results suggest that loss of p21 overexpression is associated with tumor metastasis while reduced cell cycle inhibition by p27 is associated with malignant progression.     

Assessment of movement patterns in Folsomia candida (Hexapoda: Collembola) in the presence of food

We showed that Folsomia candida (a blind soil-dwelling Collembola) was able to shift from non-directional (random or search strategy) to directional (target-oriented) movements at short distance of food. We measured departure from linearity and access (or not) to food by the springtail according to distance to the target position. Video-records and image analysis were used to obtain numerical data at 0.2 s interval. The probability of food capture within 10 min (maximum duration of the experiment) was negatively related to distance. Two patterns can be observed along successful trajectories in our experimental conditions (22 °C, ambient light, still air), non-directional movement being followed by directional movement when the animals approach food at 25 mm.