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为改善多水源灌区农业用水供需矛盾,通过合理调整种植结构,优化灌区水资源配置,该研究以河北省邯郸市漳滏河灌区为研究对象,将农业灌溉缺水量最小和农作物经济效益最大作为目标函数,兼顾灌区生态安全约束,构建了基于种植结构优化的多目标多水源优化配置模型,针对作物熟制、作物种类、种植制度以及灌溉方式设置了8种不同的种植结构优化情景,通过自主改进的基于精英策略并协遗传算法(NSGAⅡ-S)对模型求解,获得不同情景下的水资源优化配置方案。结果表明:应用模型进行水资源配置后,各情景配水总量均有所减少,其中水库配水量高于其他水源的配水量,水库水、引黄水和引江水均达到用水总量控制目标,民有分区的各计算单元间的配水量变化明显,总配水量高于滏阳河分区;适当压减主要依靠抽取地下水灌溉的冬小麦的播种面积,变灌溉农业为旱作雨养农业,可以极大地减少地下水用量,增加灌区经济效益;最佳的种植结构优化方案为CS4(削减冬小麦的种植面积,种植苜蓿,灌溉方式采取管灌或喷灌),该方案冬小麦播种面积压减17.10%,地下水开采量减少了16.42%,灌区的经济效益增加了26.41%,在保证配水总量最小的同时,具有更高的经济效益。该研究所构建的多目标多水源优化配置模型和作物配水结果可为类似地区的水资源配置提供参考。 相似文献
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通过目测进行分类的方式很难准确界定矾根品种叶色。为建立一套更为科学的基于叶色表型的矾根品种分类体系,笔者利用色差仪对72个矾根品种共计432个样品的叶色进行测定,对获得的L、a、b 3个色度值进行聚类分析,将72个矾根品种分为褐色系、深绿色系、黄色系、灰绿色系、浅绿色系5类色系。对矾根品种各色系的L、a、b值进行相关性分析,发现叶片正面的L值与a值、a值与b值呈负相关,L值与b值呈正相关,但相关性不明显;叶片背面的L值与a值、a值与b值呈负相关,L值与b值呈显著正相关。从多重比较的结果中可以看出,矾根品种各色系之间的L、a、b色度值差异显著,尤其是各色系间叶正面的颜色差异较大,在矾根品种选育工作中,叶片正面的颜色将作为主要参考。 相似文献
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Genetic diversity,anti‐microbial resistance,plasmid profile and frequency of the Vi antigen in Salmonella Dublin strains isolated in Brazil 下载免费PDF全文
F. P. Vilela M. R. Frazão D. P. Rodrigues R. G. Costa M. R. T. Casas S. A. Fernandes J. P. Falcão F. Campioni 《Zoonoses and public health》2018,65(1):e34-e43
Salmonella Dublin is strongly adapted to cattle causing enteritis and/or systemic disease with high rates of mortality. However, it can be sporadically isolated from humans, usually causing serious disease, especially in patients with underlying chronic diseases. The aim of this study was to molecularly type S. Dublin strains isolated from humans and animals in Brazil to verify the diversity of these strains as well as to ascertain possible differences between strains isolated from humans and animals. Moreover, the presence of the capsular antigen Vi and the plasmid profile was characterized in addition to the anti‐microbial resistance against 15 drugs. For this reason, 113 S. Dublin strains isolated between 1983 and 2016 from humans (83) and animals (30) in Brazil were typed by PFGE and MLVA. The presence of the capsular antigen Vi was verified by PCR, and the phenotypic expression of the capsular antigen was determined serologically. Also, a plasmid analysis for each strain was carried out. The strains studied were divided into 35 different PFGE types and 89 MLVA‐types with a similarity of ≥80% and ≥17.5%, respectively. The plasmid sizes found ranged from 2 to >150 kb and none of the strains studied presented the capsular antigen Vi. Resistance or intermediate resistance was found in 23 strains (20.3%) that were resistant to ampicillin, ciprofloxacin, chloramphenicol, imipenem, nalidixic acid, piperacillin, streptomycin and/or tetracycline. The majority of the S. Dublin strains studied and isolated over a 33‐year period may descend from a common subtype that has been contaminating humans and animals in Brazil and able to cause invasive disease even in the absence of the capsular antigen. The higher diversity of resistance phenotypes in human isolates, as compared with animal strains, may be a reflection of the different anti‐microbial treatments used to control S. Dublin infections in humans in Brazil. 相似文献
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Rafael DeRossi Rodrigo A Bertoni Rafael HS Ruzzon Alexandre B Verde‐Selva Fabrício O Frazílio 《Veterinary anaesthesia and analgesia》2010,37(5):451-459
ObjectiveTo determine the analgesic and systemic effects of epidural administration of ketamine, lidocaine or a combination of ketamine/lidocaine in standing cattle.Study designProspective, randomized, experimental trial.AnimalsSix healthy male cattle weighing between 335 and 373 kg.MethodsThe animals received 0.5 mg kg?1 of ketamine (K), 0.2 mg kg?1 of 2% lidocaine (L) or 0.25 mg kg?1 ketamine plus 0.1 mg kg?1 lidocaine (KL). All the drugs were injected into the dorsolumbar epidural space via a caudal approach through a non‐styletted multiple‐port catheter. Each animal received each treatment at random. Evaluations of analgesia, sedation, ataxia, heart rate, arterial pressure, respiratory rate, skin temperature and rectal temperature were obtained at 0 (basal), 5, 10, 15, 30, 45, 60, 75, 90 minutes after epidural injection, and then at 30‐minute intervals until loss of analgesia occurred. Skin temperature was taken at these intervals up to 60 minutes. All the animals received a standard noxious stimulus; a 4‐point scale was used to score the response. A second scale was used to score ataxia and a third for sedation.ResultsThe duration of analgesia in the upper and lower flanks in cattle was 140 ± 15, 50 ± 14 and 80 ± 22 minutes (mean ± SD) after dorsolumbar epidural KL, K or L, respectively. The cardiovascular changes were within acceptable limits in these clinically healthy cattle.ConclusionsDorsolumbar epidural administration of KL to cattle resulted in longer duration of analgesia of the upper and lower flanks in standing conscious cattle, than the administration of K or L alone.Clinical relevanceFurther research is necessary to determine whether this combination using this technique provides sufficient analgesia for flank surgery in standing cattle. 相似文献
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复种饲料油菜对麦茬耕层土壤酶活性的影响 总被引:2,自引:0,他引:2
采用大田试验方法,研究了不同种植密度与施氮量条件下,复种饲料油菜对麦茬耕层(0~15 cm)土壤酶活性的影响。结果表明,麦收后复种饲料油菜能显著或极显著地提高土壤过氧化氢酶(CAT)、酸性磷酸酶(APHA)、纤维素酶(CEL)和脲酶(URA)的活性,与休闲熟化地(CK)比较,最大提高幅度分别为32.15%,35.61%,78.66%和127.36%。土壤酶活性的变化与复种饲料油菜的播种量和施氮量有关,随播种量的增加土壤CAT、CEL和URA活性表现为逐渐递增态势,而土壤APHA表现为先增后减,播种量为11.5 kg/hm2时,APHA活性可达0.7888mg/g。在油菜生长的苗期,土壤APHA、CEL和URA随施氮量的增加而增加,土壤CAT则随施氮量的增加先增后降,呈单峰曲线;在生长后期(收获期),低氮量有利于土壤APHA活性的增加,中氮量有利于土壤CAT和CEL活性的增加,高氮量有利于URA活性的增加。 相似文献
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An experiment was conducted to analyze feed, climate and animal factors affecting dry matter intake (DMI) in lactating dairy cows. Sixteen lactating Holstein cows, with parity from 1 to 6, were assigned to a feeding trial for 2 years, comprising 31 lactations. The animals were fed Italian ryegrass silage, oat hay, alfalfa hay, beet pulp and three types of concentrate. The data, pooled and classified by stage of lactation, season of lactation and parity were analyzed by stepwise multiple regression to determine the nature and extent of factors affecting DMI. A total of 45 prediction equations for DMI were derived. Energy‐corrected milk yield or milk yield was selected as the primary factor of DMI in all the equations in which the ratio of contribution (R2) varied from 0.26 to 0.67. The dietary concentration of organic cell wall, crude fiber, crude protein, organic b fraction, forage to concentrate ratio, average ambient temperature and temperature–humidity index were selected as the secondary factors affecting DMI for pooled data, late lactation (251–350 days of lactation), summer (June–August), spring (March–May), ≥4th lactation, autumn (September–November) and 3rd lactation, respectively, and improved R2 up to 0.77. Except for an impact of bodyweight in several equations, feed and climatic factors significantly improved prediction equations effectively for data classified in different ways. To estimate DMI accurately in lactating dairy cows, feed and climatic factors should be considered for specific conditions. 相似文献
9.
Y Li H N Kadarmideen J C M Dekkers 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2008,125(5):320-329
The purpose of this study was to develop and investigate selection strategies that aim at maximizing long-term genetic response while conserving gene diversity and controlling inbreeding in populations of limited effective size, assuming complete knowledge of all genes affecting a quantitative trait. Three selection strategies were proposed to select on 100 quantitative trait loci (QTL) and compared with truncation selection on breeding value. Alternative selection strategies aimed at maximizing the average breeding value of parents with a penalty on (1) the number of unfavourable QTL genotypes among parents (OS-I), (2) the negative of the logarithm of the frequency of the favourable allele at each QTL among parents (OS-II), and (3) the average pedigree relationship among parents (OS-III). When all QTL and their effects were known, the strategies examined were able to obtain extra long-term responses, conserve QTL diversity and reduce inbreeding, compared with truncation selection. Strategy OS-II was the most effective in conserving QTL diversity and OS-III in reducing inbreeding. By changing the magnitude of the penalties applied, the impact on long-term response, inbreeding and diversity can be controlled. Extra long-term responses over truncation selection of OS-I and OS-II were even greater when effects of QTL were estimated rather than assumed known, indicating the applicability of results to practical strategies for marker-assisted selection. Extra responses are expected to be reduced for larger population sizes. 相似文献
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2011年10月-2014年10月连续3年在河北省任县安排了定位试验,通过饲用黑麦不同播期与棉花构建几种棉草复种茬口搭配方式,从产量、经济效益、水分利用效率和养分利用效率以及对土壤肥力影响等方面综合分析棉花饲用黑麦复种的可行性及复种方式。结果表明,棉花可与饲用黑麦复种,为降低饲用黑麦对棉花的影响,饲用黑麦可适当推迟到10月20日播种,次年4月底收获,效益可提高5470.1元·hm-2。棉花饲用黑麦复种与棉花单作相比,平均水分利用率提高16.49%;水分经济利用效率提高56.54%;并且土壤有机质平均增长幅度提高5.71%,土壤含盐量平均降低幅度达到23.72%,土壤改良效果明显;是适用于该区域的高效复种模式。 相似文献