Diphasic sedimentation technique complemented by a statistical approach as a useful tool to the quantification and the determination of dynamics of eggs produced by adult monogenean parasitizing groupers,Epinephelus marginatus (Lowe, 1834), in captivity

Monogenean parasites create problems in confined fish, such as at aquaculture and aquariums facilities. Strategic timing of antihelminthic treatments should be based on the dynamics of monogenean egg production which requires egg quantification, but there is no standardized analytical method. The WHO diphasic sedimentation method for helminth quantification of eggs was applied in samples with tetrahedral and fusiform monogenean eggs from six specimens of confined groupers (Epinephelus marginatus) (31 m³ sea water tank; water temperature 21.1–14.4°C; photoperiod 9:53–15 h light; November 2011 to June 2012). Helminth eggs remain in the pellet, while most organic matter was removed forming a cap. In contrast, monogenean eggs are distributed within both the pellet and cap. The diphasic sedimentation method is suitable to quantify tetrahedral and total egg number by counting those eggs in the pellet and incorporing water temperature data to obtain a statistically significant model expression (R² = 0.943; R² = 0.809), while this approach only weakly predicted fusiform egg numbers (R² = 0.297). Fusiform egg numbers declined along November–December, and increased in February–March, until June. Tetrahedral eggs decreased in November–December, but did not increase until March. The trend of egg populations and best time for antihelminthic treatment application can be set by WHO technique with the statistical approach proposed.     

Water budgeting in a carp‐prawn polyculture system: impacts on production performance,water productivity and sediment stack

This study was designed to quantify the total water requirement and consumptive water use in carp‐prawn polyculture system under different water management protocols, using water balance model. Under different water management protocols, treatment‐wise estimated total water use, TWU (×10⁴, m³) was 3.7, 4.6 and 3.9, while the computed consumptive water use index, CWUI (m³ kg^?1 biomass) was 6.62, 9.31 and 7.08, in T₁ (no water exchange), T₂ (periodic water exchange) and T₃ (regulated water exchange) respectively. Significantly higher yield (P < 0.05) in both T₂ and T₃ over T₁, was probably due to water exchange that improved the rearing environment. Although intensity of water exchange was more in T₂, significant variation (P < 0.05) in overall growth and yield was not recorded between T₂ and T₃. Treatment‐wise sediment load ranged between 54.6 and 71.3 m³ t^?1 biomasses. Higher sediment load was recorded at lower intensity of water exchange as well as with higher apparent feed conversion ratio. Higher net total water productivity, net consumptive water productivity and OV‐CC ratio in T₃ infers that regulated water exchange has a distinct edge over the no water exchange protocol. Restricted water use instead of regular/excess water exchange not only improves the production performance and water productivity, but also helps in lessening the operational pumping cost.     

Al（3＋）沉淀法制备茶多酚工艺研究

[目的]为开发利用茶多酚提供试验依据。[方法]以绿茶为原料,用乙醇作提取剂,通过超声波辅助提取得到茶多酚浸提液,然后通过单因素试验和正交试验确定Al3＋沉淀法制备茶多酚的最佳沉淀条件。[结果]单因素试验结果表明：乙醇的浸提效果优于沸水;茶叶与AlCl3.6H2O的质量比为1∶0.50时,茶多酚的沉淀率最高,为96.13%;pH为5.7时,茶多酚的沉淀率最高;20 min以内,茶多酚的沉淀率随时间的延长而增加,20 min以后,沉淀时间对茶多酚沉淀率的影响不大。正交试验结果表明：茶多酚的最佳沉淀条件为茶叶与沉淀剂AlCl3.6H2O质量之比1∶0.50,pH 5.7,沉淀时间20 min,该工艺条件下茶多酚的沉淀率达97.38%±0.35%。[结论]该提取工艺简单,无毒性,产品得率较高,纯度好。     

Influence of the cultivar,environment and management on the grain yield and bread-making quality in winter wheat

The genotype, environment and their interaction play an important role in the grain yielding and grain quality attributes. The main aim of this study was to determine the contributions of the genotype, environment and their interaction to the variation in bread-making traits. The data that were used for the analyses performed in this study were obtained from 3 locations in Poland from post-registration multi-environment trials with winter wheat in 2009 and 2010. The experimental factors were the cultivar (7 cultivars) and the crop management level (low input and high input). In the multi-environment trials, 17 traits were investigated that characterize grain, flour and dough quality. Most of the traits were affected much more strongly by environmental factors (i.e., year and location) than by genotype. The variance components revealed an especially strong effect of the year on the baking score, loaf volume and water absorption, as well a strong effect of the location on dough development and protein content. The obtained results demonstrate that the grain quality as measured by the parameters based on the protein content and quality may be substantially improved by crop management practices, especially by N fertilization level.     

进境粮谷中携带苋属检疫性杂草籽风传播扩散距离的预测

风媒传播是外来杂草传播扩散的主要途径之一。我国进口粮谷中经常携带大量苋属杂草种子,这些种子质量轻,在卸货、运输等过程中存在风传播扩散风险。本文以3种重要苋属检疫性杂草,即长芒苋、西部苋和糙果苋种子为材料,通过测定其在可能撒漏高度范围和撒漏点风速范围内的垂直沉降速度和水平扩散距离,预测苋属3种检疫性杂草在装卸及运输过程中风传播扩散范围。结果表明在风速为35 m/s,种子释放高度为35 m时,长芒苋、西部苋和糙果苋3种杂草种子的最远扩散距离分别为57.75 m、111.68 m和114.33 m。     

刺参-海蜇-对虾复合养殖系统颗粒物沉降通量研究

本文研究了刺参-海蜇-对虾复合养殖系统颗粒物沉积作用及其对刺参的影响.结果表明,刺参-海蜇-对虾复合养殖系统较单一养殖模式显著提高养殖产量(P＜0.05),其中刺参产量较单养模式提高22.6％,海蜇、对虾产量较单一养殖模式无显著差异(P＞0.05).在海蜇、对虾养殖期间,复合养殖模式颗粒物沉积量显著高于刺参单养模式,复合养殖模式沉降颗粒TOC及TN含量明显高于刺参单养模式(P＜0.05).刺参摄食海蜇、对虾单养来源的沉降颗粒物相对于摄食刺参单养来源沉降颗粒,其生长率显著升高(P＜0.05),排泄率明显较低(P＜0.05),摄食率无显著变化(P＞0.05).刺参养殖水体上层养殖海蜇和对虾,能够优化刺参食物结构,刺参-海蜇-对虾复合养殖系统充分利用水体空间,获得更高产出,提高了单位水体利用效率.     

4种漂浮液对猫粪样中曼氏迭宫绦虫卵的浮集效果

以水洗沉淀法作对比,比较了硫代硫酸钠、硫酸镁、氯化钠和硫酸锌4 种漂浮液对猫粪便中曼氏迭宫绦虫卵的浮集效果。结果表明,沉淀法的阳性粪便检出率为100%,硫代硫酸钠、硫酸锌、硫酸镁和氯化钠4 种漂浮液的阳性粪便检出率分别为100%, 97. 5%,62.5%和35%; 4 种漂浮液的浮集率分别为98.7%,10.1%,30.2%和3.0%。经F检验和多重比较方法分析,结果表明,硫代硫酸钠、硫酸镁、氯化钠和硫酸锌4种漂浮液中对虫卵的浮集效果差异显著,硫代硫酸钠漂浮液与沉淀法检查结果差异不显著,表明硫代硫酸钠漂浮液可替代沉淀法检查猫曼氏迭宫绦虫卵。     

Sediment yield variability in Northern Ethiopia: A quantitative analysis of its controlling factors

In Tigray-northern Ethiopia, lack of sediment yield data and appropriate methodologies for predicting sediment yield have contributed to poor planning resulting in rapid sedimentation in reservoirs and storage capacity loss. The objectives of this study were: (1) to assess the spatial variability of absolute sediment yield (SY) and area-specific sediment yield (SSY) and to identify their controlling factors for 11 representative catchments and (2) to develop models to predict sediment yield. We quantified sediment yield from reservoir sediment surveys and studied the role of bio-physical characteristics of the catchments and their interactions in controlling SY and SSY variability.     

应用付里叶变换近红外漫反射光谱法测定小麦面粉的SDS沉淀值

我们用FTNIRDRS方法测定了小麦面粉的SDS沉淀值,定标方程的相关系数R=0.808。