山西南部苹果花期冻害时空分布特征及综合防御技术

利用1997—2016年山西南部苹果主产县(市、区)苹果花期逐日最低气温及日平均气温观测资料，根据苹果花期冻害等级划分指标，采用最小二乘法对花期冻害日数进行线性倾向估计，并用Mann-Kendall非参数检验方法对花期冻害日数的变化趋势进行显著性检验，分析山西南部苹果花期冻害的时空分布特征。结果表明: 山西省南部苹果产区发生花期冻害日数年均为3.1 d，各县花期均温介于13.0℃~13.8℃之间。运城地区4月中上旬易发生冻害，临汾地区吉县与隰县4月下旬易发生冻害；山西南部苹果花期冻害日数近20 a气候倾向率为-0.666 d·（10 a）^-1（P≤0.01），花期极端最低气温气候倾向率为0.165 d·（10 a）^-1（P≤0.01），花期极端最低气温与冻害日数具有极显著负相关关系。山西南部苹果花期冻害日数突变点在2008年，且在2015年之后苹果花期冻害日数突破α=0.05显著性水平下限。对于苹果花期冻害的综合防御措施，可采用“以防为主，抗补结合”策略。     

基于多源遥感数据的河套灌区干旱时空演变特征

利用中国气象局陆面数据同化系统（CLDAS）验证了2015—2016年土壤水分主动-被动微波数据集（SMAP）在河套灌区的适用性，基于土壤水分亏缺指数（SWDI ）和干旱周百分比（PDW）分析了作物生育期内灌区农业干旱时空演变规律，通过两个参考指标检验了SWDI在河套灌区的精度。结果表明：（1）SMAP在河套灌区的适用性较好；区域尺度上，SMAP和CLDAS的相关系数为0.65；栅格尺度上，约有69%的栅格表现良好（R>0.5），且多集中在灌区西南部和东北部。（2）严重干旱主要发生在4月下旬到5月中旬、7月下旬到8月下旬以及9月中旬到10月中旬，主要集中在灌区的西南部、中部和东部；2015—2016年PDW值略有增大，干旱事件的持续时间有所延长。（3）大气水分亏缺量（AWD）表征的气象干旱在时间上显示2 a内灌区干旱月份为5—8月；空间上，除去地形原因，SWDI和AWD的相关性较为显著，且有一半格点通过了显著性水平为0.01的显著检验，表明基于SWDI对河套灌区进行干旱状况分析具有较高的可信度。     

不同蛋白质水平代乳粉对牦犊牛体重及血清生化指标的影响

为探究西藏地区牦牛代乳粉哺育犊牛的适宜蛋白质水平,本试验以藏区高山牦牛为研究对象,研究不同蛋白水平对哺乳期牦犊牛的体重和血清学指标的影响,以筛选出蛋白质水平最佳的代乳粉。选取40头新生当雄县牦犊牛,随机分为4组(n=10):对照组犊牛随母牦牛哺乳(CON),试验组犊牛分别饲喂蛋白水平为21.95%低蛋白组(LP)、24.28%中蛋白组(MP)和26.11%高蛋白组(HP)3种牦牛代乳品。饲喂时间为犊牛30～90d日龄,期间跟踪测定犊牛体重,并分别在30、60和90d日龄采集血清进行分析。结果表明:饲喂3种代乳粉的犊牛体重均显著高于对照组(P0.001),120d日龄时HP组犊牛体重达到最高值;3种代乳粉对犊牛血清抗氧化指标和免疫指标产生一定的影响,其中HP组谷胱甘肽过氧化物酶活性有高于LP组的趋势(0.05P0.1),且HP组丙二醛含量及肿瘤坏死因子a较其他3组低,而免疫球蛋白(IgG、IgM)及谷胱甘肽过氧化物酶、丙氨酸氨基转移酶、天冬氨酸氨基转移酶活性均较其他3组高。综合分析显示在西藏地区蛋白水平为26%的牦牛代乳粉饲喂哺乳期牦犊牛的效果较好。     

Beaver dams,streamflow complexity,and the distribution of a rare minnow,Lepidomeda copei

Freshwater fishes are threatened globally, and often too little is known about threatened species to effectively guide their conservation. Habitat complexity is linked to fish species diversity and persistence, and degraded streams often lack habitat complexity. Beaver Castor spp., in turn, have been used to restore streams and increase habitat complexity. The northern leatherside chub Lepidomeda copei is a rare, small‐bodied, drift‐feeding minnow that has anecdotally been observed to use complex habitats associated with beaver dams in the western United States. To investigate this anecdote, we conducted fish and habitat surveys, the latter focusing on quantifying habitat complexity, in a sub‐basin of the Upper Snake River Basin in the USA. Complementary generalised linear model and path analyses revealed that northern leatherside chub occurred more often at sites with complex streamflows, and streamflows were more complex when beaver dams were present and pools were deeper. Northern leatherside chubs were also more likely to occur when temperatures were warmer, aquatic macrophytes were abundant and stream channels were narrow and deep. The linkage between chubs, complex streamflows and beaver dams needs to be evaluated more broadly to completely understand its role in the rangewide status of the species. However, it does suggests that increased use of beaver reintroductions and dam analogues for stream restoration could be a boon for the northern leatherside chub, but such efforts should be monitored to determine their effectiveness to help adapt beaver‐based restoration approaches to best benefit the species.     

中药合理辐照灭菌剂量设定的初步研究

目前尚无适用于中药辐照合理剂量设定的标准,为了规范中药辐照剂量的设定,本试验参考ISO 11137的标准抗性分布(SDR),计算中药辐照的理论剂量,并与9种中药粉和1种丸剂的实际系列辐照剂量进行比对。结果表明,丸剂和个别中药粉理论剂量比实际剂量偏小,达到-88%~-50%;有7种中药粉的理论剂量与实际剂量基本一致,偏差约为1k Gy。推断大部分中药粉可以通过SDR计算出合理的理论剂量,但对丸剂不建议按照SDR直接进行辐照剂量设定。本研究结果有效地提高了中药合理剂量筛选的效率,降低辐照风险,为中药辐照灭菌剂量的合理设定提供了方法参考。     

An assessment of carcass counting surveys with increasing time lapse following a simulated fish kill on a small upland stream

A simulated fish kill was conducted on a small upland stream in Northern Ireland by planting out hatchery‐produced brown trout Salmo trutta L. carcasses of various size categories. Standard, post‐fish kill, assessment walkover surveys were conducted over time intervals to determine the number of carcasses visible. The sample variance between individual surveyors was generally low, with good agreement between the observed counts for the three, discrete, size fractions of fish up to 72 hr after the simulated fish kill. Despite low discharge rates, shallow water and good accessibility to the experimental stream, only 52% of the small category fish (<8 cm L_F) were recorded 4 hr after the start of the simulated fish kill. Larger carcasses (>17 cm L_F) were more visible, and >90% were detected 48 hr after the start of the simulated fish kill. After 96 hr, all size fractions of carcasses had reduced significantly, and the variability between replicate surveys increased markedly.     

拟态弧菌感染黄颡鱼的动态病理损伤及病原分布研究

以1.0×106CFU·m L~(-1)拟态弧菌(Vibrio mimicus)浸浴感染黄颡鱼(Pelteobagrus fulvidraco),于第0、第4、第8、第16、第24、第36、第48、第60、第72小时剖杀取样,研究病理损伤及病原菌的体内动态分布。结果显示,皮肤肌肉、鳃、肠道出现病变最早,其中皮肤肌肉损伤最严重。第16小时表皮变性、坏死,鳃上皮肿胀,肠绒毛水肿;第24~第48小时表皮坏死、脱落,真皮严重出血,肌纤维变性、坏死,鳃出血,上皮局部坏死,肠上皮变性与灶性坏死;第48~第72小时皮肤肌肉坏死更严重,形成溃疡灶,鳃灶性坏死。肾、肝、脾与心36 h后相继出现不同程度的淤血、出血,变性和灶性坏死。q PCR检测发现,第4小时即在鳃、肠、皮肤肌肉检出病菌,细菌含量分别为1.3×102CFU·mg~(-1)、2.6×102CFU·mg~(-1)、4.7×102CFU·mg~(-1);鳃与皮肤肌肉中菌量随时间延长而增加,第72小时皮肤肌肉中菌量达到4.5×107CFU·mg~(-1);第24小时后相继在肾、肝、脾、心检出病菌,菌量介于1.9×10~4.7×102CFU·mg~(-1)之间。结果表明皮肤、鳃和肠道是病菌的入侵位点,并在体内多组织、器官分布。     

Large‐scale patterns of fish diversity and assemblage structure in the longest tropical river in Asia

Although the Mekong River is one of the world's 35 biodiversity hot spots, the large‐scale patterns of fish diversity and assemblage structure remain poorly addressed. This study aimed to investigate the fish distribution patterns in the Lower Mekong River (LMR) and to identify their environmental determinants. Daily fish catch data (i.e. from December 2000 to November 2001) at 38 sites distributed along the LMR were related to 15 physicochemical and 19 climatic variables. As a result, four different clusters were defined according to the similarity in assemblage composition and 80 indicator species were identified. While fish species richness was highest in the Mekong delta and lowest in the upper part of the LMR, the diversity index was highest in the middle part of the LMR and lowest in the delta. We found that fish assemblages changed along the environmental gradients and that the main drivers affecting the fish assemblage structure were the seasonal variation of temperature, precipitation, dissolved oxygen, pH and total phosphorus. Specifically, upstream assemblages were characterised by cyprinids and Pangasius catfish, well suited to low temperature, high dissolved oxygen and high pH. Fish assemblages in the delta were dominated by perch‐like fish and clupeids, more tolerant to high temperatures, and high levels of nutrients (nitrates and total phosphorus) and salinity. Overall, the patterns were consistent between seasons. Our study contributes to establishing the first holistic fish community study in the LMR.     

Long-Term and Immediate Effects of Whole Body Vibration on Chronic Lameness in the Horse: A Pilot Study

The effects of whole body vibration (WBV) in horses with chronic lameness were evaluated in an experimental, single subject, repeated measure design. To assess the long-term effect of WBV, eight horses not previously exposed to WBV were subject to WBV, 30 minutes twice daily, five days a week, for 60 days in addition to their regular exercise routine. Lameness was assessed subjectively and objectively 30 days before the start, at the start and 30 and 60 days after the start of the treatment (WBV). The immediate effect of WBV was assessed in four horses accustomed to WBV, by comparing lameness before and within 30 minutes of a single 30-minute WBV session at four different time intervals. Change in lameness was sought using paired t tests on the kinematic data. A P-value of <.05 was considered statistically significant. Intraindividual change was sought using a subjective and objective scoring system. No statistically significant change in lameness was seen after 30 or 60 days of WBV, respectively, in the chronically lame horses not previously exposed to WBV. However, a trend toward improvement was observed after the first 30 days of WBV, but this improvement appeared to be lost during the second 30 days of WBV. Although a statistically significant worsening of front limb lameness was seen immediately after a single 30-minute WBV session in the chronically lame horses accustomed to WBV, this result was largely attributed to a very significant worsening of the front limb lameness in one horse within that group.