Feline urological syndrome

CASE HISTORY: Torsion of the descending colon was diagnosed by barium enema radiography in an adult Irish Water Spaniel which had presented with tenesmus of 24 h duration. Treatment involved exploratory laparotomy, repositioning of the colon, colopexy and repair of a mesenteric rent. No definitive cause of the torsion could be established. The dog made an uneventful recovery from surgery.

CLINICAL RELEVANCE: Animals presenting with constipation of undetermined cause should have large intestinal obstruction ruled out prior to administering bowel cleansing solutions per os and/or colonic enemas. Colonic obstruction by torsion should be considered as a possible differential diagnosis in all cases of tenesmus.     

江西省中小河流治理规划研究

分析了江西省中小河流防洪现状及存在的问题,介绍了江西中小河流治理规划及实施的情况,最后就加快中小河流治理提出了建议。     

试论灌木林在青海三江源生态建设中的地位

文章在分析三江源灌木林的历史与现状的基础上,阐述了灌木林主要功能及其在生态建设中的地位,提出了恢复与发展灌木林的主要措施。     

三江源区径流量变化特征与人为影响程度

应用降水量、气温、蒸发量和径流量的实测统计数据,运用Excel,SPSS软件进行多元线性回归分析,研究三江源区天然径流量变化,并评价其人为影响程度.结果表明:该区径流量变化具有超前性,是径流变化的启动区,气温和降水量具有增加径流作用,蒸发量具有削减径流作用,1982年以前径流量的人为影响较小.1983年后径流的人为影响程度具有增大趋势,吉迈和唐乃亥人为影响程度都低于50%,黄河沿多数年份人为影响程度为50%-80%.黄河源区影响径流量变化的主导因素在东部,是自然因素;西部是人为因素,即径流量的人为影响存在西强东弱的区域差异,越靠近源头地区径流量的人为影响越强烈.     

渭-库绿洲多尺度景观格局与盐度关系

中国盐渍化土壤面积大,分布广,对区域农业发展构成了严重的威胁。探索土壤景观格局与盐度的关系将有助于盐渍化监测和评估。该研究选择渭-库绿洲GF-1影像为数据源,结合研究区同期38个样点不同剖面土壤盐度数据,对样点缓冲区景观格局与土壤盐度做Pearson相关分析和逐步回归分析,揭示土壤盐度空间分布格局,探讨景观格局与盐度的定量关系。结果表明:1)水平方向上,土壤盐分高值区主要集中分布在绿洲东部荒漠地带和绿洲西部农牧交错区;垂直方向上,渭-库绿洲表层土壤盐渍化现象最为严重,其他各层土壤盐渍化情况相对较轻,盐渍化程度随着深度下降呈降低趋势;2)绿洲区域易受人类活动影响,景观破碎化程度高,而同一区域不同梯度下,随着缓冲距离的增加,区域景观类型增多、均质性降低、多样性增强;3)耕地利用数量指标能较好指示土壤盐度状况,而水体面积、盐渍地面积、其他用地面积、最大斑块指数(largest patch index,LPI)、蔓延度(contagion index,CONTAG)和分维数(perimeter-area fractal dimension,PAFRAC)对盐度影响相对较弱;4)除0~10 cm层外,自10~20 cm至80~100 cm层逐步回归方程的自变量中,耕地面积、水体面积和最大斑块指数LPI为负效应,而盐渍地面积、其他用地面积、CONTAG和PAFRAC为正效应,最优回归方程决定系数为0.537。该研究确定了渭-库绿洲土壤盐度的分异规律,以及不同盐度对绿洲景观格局的影响程度。研究结果可为西北干旱区绿洲土壤盐度预警提供理论依据,同时为干旱区景观格局研究提供一定的参考价值。     

Modelling riverine habitat for robust redhorse: assessment for reintroduction of an imperilled species

A critical component of a species reintroduction is assessment of contemporary habitat suitability. The robust redhorse, Moxostoma robustum (Cope), is an imperilled catostomid that occupies a restricted range in the south‐eastern USA. A remnant population persists downstream of Blewett Falls Dam, the terminal dam in the Pee Dee River, North Carolina. Reintroduction upstream of Blewett Falls Dam may promote long‐term survival of this population. Tillery Dam is the next hydroelectric facility upstream, which includes a 30 rkm lotic reach. Habitat suitability indices developed in the Pee Dee River were applied to model suitable habitat for proposed minimum flows downstream of Tillery Dam. Modelling results indicate that the Tillery reach provides suitable robust redhorse habitat, with spawning habitat more abundant than non‐spawning habitat. Sensitivity analyses suggested that suitable water depth and substrate were limiting physical habitat variables. These results can inform decisions on flow regulation and guide planning for reintroduction of the robust redhorse and other species.     

基于人水和谐的城市污水河流生态治理

文章在简述城市污水河流概况的基础上,介绍了城市污水河流目前存在的问题。针对城市污水河流五大问题,以人水和谐为指导,本着统一规划,综合治理,按照改善环境与防洪排水相结合、维护自然生态与满足行洪排水要求相结合、生态湿地与滞洪蓄洪相结合的三大原则,给出相应的五大建议措施。城市污水河流水系实施生态治理不仅对城市发展主题具有巨大的提升和促进作用,而且将有助于改善当地的水体环境和沿河的投资环境,促进该地区社会、经济的可持续发展,实现人水和谐,为城市污水河流改善治理提供参考。     

基于机器视觉的河水表面流速估计

为了解决河水流速的视频测量需要投掷浮标、效率低等问题,提出了基于机器视觉的河水表面流速测量方法。采用高清摄像机拍摄河水流动视频,捕捉河水流动时表面产生的波浪运动。为了凸显这些细微的水面运动,利用帧差法计算运动显著性图。提取相邻2帧显著性图的SURF特征点,通过特征点匹配法找出相邻2帧的匹配点,将匹配点间的距离作为特征点在2帧图像间的运动距离。计算了多帧图像间特征点运动距离的直方图,该直方图具有单峰特征;通过对直方图进行曲线拟合准确地找到峰值对应的距离,将其作为最优的运动距离。最后结合帧间时间和根据小孔成像原理导出的速度公式估计出河水表面流速。为了验证该方法的有效性,用流速仪和该方法进行了对比试验。结果表明,该方法具有精度好、稳定性高和运算速度快的优点。在低、中速河流速度估计时,该方法最大变异系数为1.63%,与流速仪测量结果的最大相对误差仅为3.12%。对2组数据的一致性分析表明,2组数据的皮尔逊相关系数和斯皮尔曼相关系数分别为0.998和0.990,显示了该方法的速度估计值与流速仪实测值有良好的一致性。与已有的图像处理方法相比,不仅更为准确,而且耗时更短。研究可为用其他机器视觉处理算法估计复杂水面和高速水流提供参考。     

Fishery yields vary with land cover on the Amazon River floodplain

Inland fisheries underpin food security in many tropical countries. The most productive inland fisheries in tropical and subtropical developing countries occur in large river–floodplain systems that are often impacted by land cover changes. However, few studies to date have assessed the effects of changes in floodplain land cover on fishery yields. Here, we integrated fisheries and satellite‐mapped habitat data to evaluate the effects of floodplain deforestation on fishery yields in 68 floodplain lake systems of the lower Amazon River, representing a wide range in relative amounts of woody, herbaceous and non‐vegetated land cover. We modelled relative fish yields (fish capture per unit effort [CPUE]) in the floodplain lakes as a function of the relative amounts of forest, shrub, aquatic macrophyte and bare/herbaceous habitats surrounding them. We found that forest amount was positively related (p = .0003) to multispecies CPUE. The validity of these findings was supported by rejection of plausible alternative causative mechanisms involving habitat‐related differences in amount of piscivores, fishing effort, lake area, and habitat effects on CPUE of the nine taxa dominating multispecies yields. Our results provide support to the idea that removal of floodplain forests reduces fishery yields per unit effort. Increased protection of floodplain forests is necessary to maintain the food, income and livelihood security services provided by large river–floodplain fisheries.     

Morphological Similarity of Channels: From Linear Erosional Features (Rill,Gully) to Alpine Rivers

The geometric characteristics of incised features such as channels, rills, ephemeral gully, gully, represent the erosional transport regime and the fluvial dynamic equilibrium, and thus it is critical for the understanding of the long‐term evolution of natural, agricultural, and anthropogenic landscapes. This paper examines the morphological similarity of channelized erosion in two different environments such as Alpine landscapes and cultivated hillslopes. The first dataset comprises six rivers in the Italian Alps, three in the Carnia region and three in the Dolomites, where erosion is mainly the effect of discharges with high sediment loads or landslides and debris flows. The agricultural areas dataset includes rills, ephemeral gullies, and gullies surveyed in literature. This research highlights that the eroded volume in Alpine rivers is in line with that of agricultural landscapes or badlands around the world. Dolomites rivers of colluvial origin, flowing on soils that are not particularly deep and subject to natural disaggregation, tend to behave similarly to ephemeral gullies. Contrarily, channels that exhibit evident alluvial morphologies and coarse grain sizes are more similar to gully erosion. At different spatial scales, the results demonstrated that length–volume equations calibrated on rills, ephemeral gullies, gullies and badlands, might be feasible also for Alpine channels. The research areas present soils and bedrock lithology that differs from those in literature, thus suggesting that the morphology of linear erosion is independent of the intrinsic soil characteristics. Differences emerged between Dolomites and Carnia rivers: this highlights the importance of taking into account in future analyses other forcing factors (e.g. climate) on land degradation processes. Copyright © 2017 John Wiley & Sons, Ltd.