Methods for Comparing the Yield Stability of Cropping Systems

The stability of yield is an important characteristic to be considered when judging the value of a cropping system relative to others. In the context of agricultural research, the analysis of yield stability has been largely confined to multienvironment trials of crop cultivars. This review emphasizes that methods for comparing the stability of cultivars can also be used for comparing different agronomic treatments in general, of which cultivars are but a special case. Throughout the paper, different agronomic treatments are referred to as cropping systems. Some of the methods useful for stability analysis of cropping systems are discussed and a brief review of applications of these methods is given. The paper puts different stability measures into a unifying mixed model perspective.     

Day-to-Day variation of the urine protein: creatinine ratio in female dogs with stable glomerular proteinuria caused by X-linked hereditary nephropathy

BACKGROUND: Interpretation of serial urine protein:creatinine (UPC) values is confounded by a lack of data regarding random biologic variation of UPC values in dogs with stable glomerular proteinuria. HYPOTHESIS: That there is minimal day-to-day variability in the UPC of dogs with unchanging proteinuria and the number of measurements needed to reliably estimate UPC varies with the magnitude of proteinuria. ANIMALS: Forty-eight heterozygous (carrier) female dogs with X-linked hereditary nephropathy (XLHN) causing stable proteinuria. METHODS: Urine samples were obtained daily by cystocentesis for 3 consecutive days on 183 occasions (549 samples). The UPC was measured for each sample with a single dry-film chemistry auto-analyzer. Data were analyzed retrospectively by a power of the mean model because the variance of UPC values within the 3-day evaluation periods increased as the magnitude of proteinuria increased. RESULTS: To demonstrate a significant difference (P < .05) between serial values in these proteinuric dogs, the UPC must change by at least 35% at high UPC values (near 12) and 80% at low UPC values (near 0.5). One measurement is adequate to reliably estimate the UPC when UPC <4, but 2-5 determinations are necessary at higher UPC values. CONCLUSIONS AND CLINICAL IMPORTANCE: These guidelines for interpretation of serial UPC values in female dogs with XLHN may also be helpful for interpretation of UPC values in dogs with other glomerulopathies.     

金钱豹血液理化值的测定

广州动物园科研中心于2003年10月至2005年3月间共采集11只金钱豹的34份血液样本，对40项临床常用的血液生理生化值进行了测定，结果用SPSS11．0统计软件进行统计分析。     

热带作物田间废弃物多功能粉碎综合实验装置研究

介绍热带作物田间废弃物多功能粉碎综合实验装置的组成及其工作原理,详细论述该实验装置小车行走与控制,刀辊组件转速、直径、刀片、刀辊长度等的调节,粉碎工作室形状调节,实验数据自动采集与信息化处理等设计问题。该装置对于系统开展热带作物田间废弃物粉碎设备的基础实验研究具有重要意义。     

不同热加工方式对翼柄柔鱼品质的影响

探究煮制、油炸、烤制3种热加工方式对翼柄柔鱼(Sthenoteuthis pteropus)色泽、质构、硫代巴比妥酸值、生物胺及挥发性组分等指标的影响。结果表明：热加工处理后,翼柄柔鱼色泽发生明显改变,油炸处理组色泽与其他处理组差异性显著;鱿鱼的硬度和咀嚼性发生了显著变化,煮制与其他处理组相比,弹性存在显著差异;样品经不同热加工方式后的氧化程度：煮制>油炸>烤制。热加工对6种生物胺的影响存在差异：亚精胺、酪胺及精胺总体含量较低,差异不显著;生鲜鱿鱼中组胺含量为(3.23±0.20) mg/kg,经热加工分别增加了1.29倍(煮制)、3.68倍(油炸)、2.89倍(烤制)。采用SPME-GC-MS方法对生鲜、煮制、油炸、烤制翼柄柔鱼进行挥发性化合物检验,分别检出46、52、61、70种挥发性化合物。不同热加工方式对翼柄柔鱼色泽、质地、风味等食用品质的影响存在差异。研究结果为鱿鱼的热加工提供了理论指导。     

耕作方式对土壤腐殖质结合状态及组成的影响

为明确不同耕作方式下土壤腐殖质结合形态及组成的变化规律,依托8年定位耕作试验,采用大田取样、室内分析相结合的方法对其进行了研究。结果表明:各种耕作方式下土壤腐殖质均以紧结态腐殖质为主,其含量占重组有机碳的50%以上;传统耕作方式(CTA)松结态、稳结态腐殖质含量随试验年限延长而增加,但紧结态腐殖质含量及其在重组碳中所占比例呈下降趋势,传统耕作方式下腐殖质趋向于分解退化;旋耕秸秆还田方式(RTS)松结态、紧结态腐殖质含量年增加速率分别达0.08和0.31 mg/g,且其稳结态腐殖质含量最高,旋耕秸秆还田有利于土壤腐殖质的更新与积累;土壤耕作及由此引起的秸秆分布位置不同是促进对应层次松结态腐殖质含量增加的重要原因;秸秆还田条件下对土壤的扰动,增加了土壤的腐殖化度。     

微藻水热液化有机相最佳回收工艺研究

以微拟球藻为原料,研究微藻水热液化过程中多种参数对水热液化后有机物回收率的影响,包括温度、时间、溶剂比和pH等,从而获得微藻水热液化后有机物的最佳回收工艺条件。结果显示,在室温下进行有机相回收,保证回收溶剂比为20∶1(溶剂/水相不溶物;v/wt)、停留时间为10min、回收pH7,即可达到最佳回收效果。最佳条件下水热液化有机相的回收率为34%左右,且不同的回收温度和pH值对回收的有机相组分均会产生影响。     

抑芽剂不同施用方法对烤烟中性致香物质含量的影响

以烤烟品种红花大金元为供试材料,研究了抑芽剂不同施用方法对烤烟中性致香物质含量的影响。结果表明:经过抑芽处理后的烟叶中性致香物质含量明显高于对照(CK1);化学抑芽较手工抑芽对烟叶中性致香物质含量的影响更明显,各处理烟叶中类胡萝卜素类、苯丙氨酸类、类西柏烷类、美拉德反应产物类、新植二烯等致香物质含量均高于对照(CK2),其中T4处理(涂抹,两次施药)中性致香物质含量最高。     

蜂王浆中不同活性组分对大鼠降血脂效果影响

将新鲜王浆经过180目滤网过滤,滤液再逐步经过0.5 μm、0.1 μm和0.05 μm的无机陶瓷膜过滤,分别得到5种蜂王浆活性组分.试验用健康雄性Wister大鼠,给予高脂颗粒饲料喂饲后第9 d,大鼠眶静脉取血,测定血清总胆固醇(TC)、甘油三酯(TG)和高密度脂蛋白(HDL-C)值.高脂血症动物模型成功后,随机分为模型对照组和蜂王浆及各活性组分实验组,同时设置正常对照组,每组10只大鼠.分组后连续6周灌胃蜂王浆及各活性组分,同时继续给予高脂颗粒饲料喂饲,之后各组大鼠取血测定TC、TG和HDL-C.结果表明:42 d后,新鲜王浆(A组)、经180目滤网过滤的滤渣(B组)、经0.5 μm陶瓷膜过滤的滤渣(C组)和再经0.1 μm陶瓷膜陶过滤的滤渣(D组)能显著降低大鼠血清TC含量;A、D组和经多次过滤后的滤液(F组)都有显著降低大鼠血清TG含量的作用;在提高HDL-C含量方面,A组、经0.05 μm的无机陶瓷膜过滤的滤渣(E组)和F组都起作用,其它各组无效果.     

玉米自交系及杂交种抗青枯病鉴定

1986-1989年采用自然鉴定和人工土壤接种鉴定的方法，对602份玉米材料的青枯病抗性进行了鉴定。人工接种鉴定397份，其中204份材料表现抗病。在正常年份，人工接种鉴定效果明显好于自然鉴定，但在重病区或青枯病流行年份，在尚未具备人工接种条件时，利用自然发病作为选育抗病材料仍有一定效果。玉米苗期接种青枯病重于成株期