盐碱土秸秆添加量对玉米种子萌发及幼苗生长特性的影响

探索盐碱土中添加最佳玉米秸秆量,以‘农华101’玉米种子、收获期玉米秸秆和通辽地区典型的盐碱土为材料,用盐碱土:蒸馏水(1:5)的土壤浸出液制备0、30、40、50、60 g/L秸秆粉培养液,作为5个处理,水培玉米种子;培养期间测定培养液pH、电导率、微生物数量及玉米幼苗根系内生菌数量,统计种子发芽率,4叶期测定幼苗农艺性状及其叶片和根系生理特性指标。结果表明：盐碱土添加玉米秸秆降低pH,降低玉米种子发芽率,但极显著增加幼苗根长、根数和株高;其中40 g/L处理对根长、根数的增加幅度最大,0 g/L处理2叶期死亡。添加秸秆极显著增加盐碱土细菌数量,除了30 g/L处理,其余处理极显著增加真菌和放线菌数量。根内生真菌和放线菌各处理无显著差异,30 g/L与40 g/L根内生细菌数显著大于50 g/L与60 g/L处理。40 g/L处理叶片POD活性极显著大于50、60 g/L处理,分别是它们的2.22倍和3.15倍;叶片MDA含量排序为60 g/L>50 g/L>30 g/L>40 g/L,处理间差异极显著;叶片SOD活性和根系活力为40 g/L>50 g/L>60 g/L>30 g/L,处理间差异极显著;根系MDA含量排序为60 g/L>30 g/L>50 g/L>40 g/L,处理间差异极显著;各处理根系POD活性规律与根系活力一致。盐碱土添加玉米秸秆可增加玉米幼苗抗盐碱胁迫能力,其中40 g/L处理最为显著。     

基于时域和频域的层积材强度检测系统

为对层积材强度进行无损在线检测,设计了一种基于时域和频域分析法的层积材强度检测系统,并阐述了该系统的检测原理、系统构成和软件实现。该系统采用研华开发的PCI-1710HG采集卡进行数据采集,以工控机为数据处理核心,通过提取振动信号对数衰减率和试件各阶固有频率实现层积材强度的检测。最后通过验证实验证明,该系统设计是可行的。      

Cefquinome Concentrations in Endometrium after Intrauterine Treatment of Cobactan 4.5%® in Mares and Inflammatory Response of the Endometrium to this Treatment

This study was conducted to measure the concentration of cefquinome in the endometrium of mares after intrauterine treatment and to evaluate associated inflammation. Mares (n = 14) were randomly assigned to one of the following groups: (i) control (n = 4) were either not treated (n = 2) or received (n = 2) lactated Ringer's intrauterine for 1 or 3 days; (ii) treated mares (n = 10) received intrauterine cefquinome for 1 or 3 days. After at least 10 days had passed following the last treatment and ovulation, mares were given Prostaglandin F2α (PGF2α) and were randomly assigned to an alternate treatment. Endometrial biopsy samples were taken at 2, 8, 24 and 48 h, or at 4, 12 and 36 h, after the last treatment. Biopsy samples were taken at the same time points from control mares (n = 2) and lactated Ringer-treated mares (n = 2). Cefquinome concentrations were quantified using a high-performance liquid chromatography (HPLC) assay and inflammation was assessed using haematoxylin and eosin (H&E)-stained sections. Concentrations of cefquinome [559 (1 day) and 595 μg/g (3 days) at 2 h, and 403 (1 day) and 370 μg/g (3 days) at 4 h] were similar between treatment groups at 2 and 4 h after treatment (p > 0.05). At 8 h, as well as at 24 and 48 h, concentrations were greater in the 3-day group (17 vs 301 μg/g, 3 vs 80 μg/g and 0.1 vs 0.2 μg/g, respectively) (p < 0.05). No significant differences (p > 0.05) in the inflammatory response at 2–48 h after treatment were found between groups.     

Temporal dynamics of root and foliar severity of soybean sudden death syndrome at different inoculum densities

Temporal dynamics of soybean sudden death syndrome (SDS) root and foliar disease severity were studied in growth chamber experiments on susceptible plants exposed to different inoculum densities (0, 10⁰, 10¹, 10², and 10³ conidia g⁻¹ soil) of Fusarium virguliforme. The monomolecular model provided the best fit to describe the progress of root and foliar disease severity over time. Disease severity and area under disease progress curve (AUDPC) both increased in response to increasing inoculum density (P < 0.01), particularly for foliar symptoms. Rate of disease progress increased as inoculum densities increased for both root and foliar disease severities. The incubation period for root and foliar disease severity ranged from 9 to 18 and 15 to 25 days, respectively. Significant differences in root rot severity were most easily detected during the early stages of infection, whereas root rot and foliar severities were only weakly correlated when both were assessed simultaneously at later stages of disease development. Root rot severity assessments performed 15 to 20 days after inoculation (DAI) were most highly correlated (r > 0.9, P < 0.01) with foliar disease severity assessments performed 30 to 50 DAI. Root biomass was reduced by up to 67% at the three highest inoculum densities, indicating the aggressiveness that F. virguliforme possesses as a root rot pathogen on soybeans.     

Comparison of acetate tape impression with squeezing versus skin scraping for the diagnosis of canine demodicosis

This study compared the sensitivity of acetate tape impression and skin squeezing with that of deep skin scraping for the diagnosis of demodicosis in dogs. Demodex canis was detected in 100% of acetate tape impressions obtained after skin squeezing and in 90% of deep skin scrapings. There was a significant difference (P < 0.001) between the techniques in the total number of mites detected. Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis.     

SONOGRAPHIC RENAL FINDINGS IN 20 DOGS WITH LEPTOSPIROSIS

Abdominal ultrasound examinations of 20 dogs with confirmed leptospirosis were reviewed retrospectively for renal abnormalities. Three dogs had a normal ultrasound examination. The remaining 17 dogs had sonographic abnormalities of the kidneys. These abnormalities, seen either alone or in combination, included renalmegaly (n=10), pyelectasia (n=9), increased cortical echogenicity (n=15), perinephric effusion (n=5), and a medullary band of increased echogenicity (n=6). At our institution, the medullary band of increased echogencity has only been seen in dogs with leptospirosis and may therefore be a specific sonographic sign for this disease.     

不同年限玉米秸秆还田对土壤微生物多样性的影响

秸秆还田是培肥地力、改良土壤的重要措施。内蒙古高原向松辽平原过渡地带春玉米区,玉米长期连作导致了耕层变薄、土壤次生盐渍化等土壤退化问题。采用田间定位试验的方法,研究连续多年(8、5、2年)秸秆旋耕还田条件下对土壤微生物的影响。结果表明,秸秆还田土壤中最丰富的细菌类型为变形菌门(Proteobac-teria),其次为放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)、拟杆菌门(Bacteroidetes);真菌类型为子囊菌门(Ascomycota)和担子菌门(Basidiomycota)。随着秸秆还田年限的增加,变形菌门和酸杆菌门(Acidobacteria)相对丰度增加、放线菌门相对丰度下降,拟杆菌门相对丰度较稳定;子囊菌门、担子菌门、接合菌门(Zygomycota)相对丰度先下降后上升,而球囊菌门(Glomeromycota)和壶菌门(Chytridiomycota)相对丰度变化规律相反;属水平上Sphingomonas、Lysobacter、Hannaella相对丰度先上升后下降,而Leptosphaeria和Mono-dictys相对丰度变化规律相反;Pseudarthrobacter、Fusarium相对丰度下降,Gaiella相对丰度较稳定;Guehomyces相对丰度增加;并且细菌和真菌相对丰度拐点均出现在秸秆还田5年后。随着秸秆还田年限的增加,土壤细菌和真菌多样性均有所降低;秸秆还田与秸秆不还田土壤的差异物种有Aquicella、Fusicolla和Spizellomyces;由此可推测,秸秆还田增加土壤氮和钾含量,减少病害;试验区连续多年的玉米秸秆还田改变了土壤微生物群落组成,玉米秸秆连续还田5年后土壤微生物多样性有下降趋势。     

Clinical evaluation of protein electrophoresis of cerebral spinal fluid

Protein fractions of cerebral spinal fluid samples were analyzed in an effort to find a reliable, minimally invasive and cost effective method of diagnosing cervical vertebral myelopathy. There were six separate protein fractions analyzed by electrophoresis. In this study we specifically looked for a post beta spike in horses with spinal cord compression. There was no correlation in our study between horses with a post beta spike and CVM as diagnosed by a myelogram.     

The interim management procedure approach for assessed stocks: Responsive management advice and lower assessment frequency

Stock assessments are often used to provide management advice, such as a total allowable catch (TAC), to fishery managers. Many stocks are not assessed annually, and the TAC from the previous assessment is often maintained in years between assessments. We developed two interim management procedures (MPs) that update the estimate of current vulnerable biomass from a surveyed index of abundance to adjust the TAC from a previous assessment. These MPs differ in how they handle uncertainty in observed indices. Using closed‐loop simulation, we evaluated the two interim MPs (with 10‐ and 5‐year assessment intervals) against several “status quo” approaches: (1) an annual assessment, and (2) a stock assessment every 5 or 10 years with (a) fixed TACs or (b) projections between assessments. We evaluated performance across three life‐history types and six operating model scenarios. The interim MPs performed similarly to annual assessments in terms of trends in biomass and yield, regardless of the assessment interval of the interim MPs. The interim MPs often produced more yield than the Fixed TAC MP with 10‐year assessment intervals, for example, in depleted scenarios. The Fixed TAC MP performed more similarly to interim MPs when the assessment interval for the Fixed TAC MP was decreased to five years. The interim MPs can also perform well when circumstances arise that are not accounted for in the Projection MP. Our results show that interim MPs should be considered for infrequently assessed stocks or rebuilding stocks, and highlight potential cost savings of interim MPs over annual assessments.