海带病害防治诊断专家系统的研究

海带病害的诊断和防治是保障海带健康养殖的关键。为了提高海带养殖用户的病害诊断和防治水平,本文对海带病害诊断专家系统进行了研究。首先,研究了知识的获取,以学术期刊发表的文献为主,同时辅以专家的调研,收集整理28种海带病害;接着,选择产生式规则描述知识,并构造了规则库;最后,采用正向推理进行病害诊断。该系统采用JSP+Sevlet+JavaBean实现,可以满足海带养殖用户对病害防治诊断的需求,并指出了下一步的研究方向和内容。     

天津市蔬菜生产基地保鲜技术设施发展现状与建议

蔬菜作为鲜活农产品,在贮运过程中易发生变质腐烂现象,损耗严重。本文通过调研了解掌握天津市蔬菜生产基地保鲜技术设施发展现状,针对天津市蔬菜生产基地保鲜技术设施存在的问题,提出天津市蔬菜生产基地保鲜技术设施发展建议,以期为我市蔬菜生产基地保鲜技术设施发展提供参考。     

Genomic footprints of wheat evolution in China reflected by a Wheat660K SNP array

Common wheat(Triticum aestiuum L.)is one of the most important crops because it provides about 20%of the total calories for humans.T.aestiuum is an excellent modern species for studying concerted evolution of sub-genomes in polyploid species,because of its large chromosome size and three well-known genome donors.Establishment of common wheat genome reference sequence and development of high-density SNP chips provide an excellent foundation to answer questions of wheat evolution and breeding at the genomic level.By genotyping more than 600 accessions of common wheat and their diploid and tetraploid ancestors using a Wheat660 K SNP array,we found dramatic genome changes due to tetraploidization and hexaploidization,in contrast to weaker influences of domestication and breeding on them.Further,since common wheat was introduced in China in 1500 BCE,Chinese landraces formed two subgroups(T.aestiuum-L1 and T.aestiuum-L2)with considerably diverse geographic distributions and agronomic traits.T.aestiuum-L2,mainly distributed in central and east China is found to have more but smaller oval grains with early maturity characteristics.We found that variation and selection in intergenic regions of the A and B sub-genomes dominated this differentiation,in which chromosomes 7 A and 3 B took the leading roles due to the existence of putative genes related to defense responses and environmental adaption in the highly differentiated regions.Large haplotype blocks were detected on 3 B(232.6-398.3 Mb)and 7 A(211.7-272.9 Mb)in the landraces,forming two distinct haplotypes,respectively.We discovered that artificial crosses in breeding promoted recombination in the whole genome,however,this recombination and differentiation was highly asymmetric among the three sub-genomes in homoeologous regions.In addition,we found that the wide use of European and northern American cultivars in breeding at early era,led dramatic changes in Chinese wheat genome,whereas,the recent breeding functioned to optimize it.This study will provide the insight for reconsideration of wheat evolution and breeding,and a new strategy for parent selection in breeding.     

提高肉用鹧鸪生产性能的关键技术

鹧鸪养殖具有易饲养、周期短、疾病少、低成本、报酬高、销路广等优点,深受饲养者的欢迎。本文从鹧鸪育雏管理,科学饲养,卫生防疫等方面对提高肉用鹧鸪生产性能进行综合论述,以供广大饲养者参考。     

Generation of a uniform thymic malignant lymphoma model with C57BL/6J p53 gene deficient mice

Lymphoma is the third most common cancer diagnosed in children, and T-cell lymphoma has the worst prognosis based on clinical observations. To date, a lymphoma model with uniform penetrance has not yet been developed. In this study, we generated a p53 deficient mouse model by targeting embryonic stem cells derived from a C57BL/6J mouse strain. Homozygous p53 deficient mice exhibited a higher rate of spontaneous tumorigenesis, with a high spontaneous occurrence rate (93.3%) of malignant lymphoma. Because tumor models with high phenotypic consistency are currently needed, we generated a lymphoma model by a single intraperitoneal injection of 37.5 or 75 mg/kg N-methyl-N-nitrosourea to p53 deficient mice. Lymphoma and retinal degeneration occurred in 100% of p53^+/− mice administered with higher concentrations of N-methyl-N-nitrosourea, a much greater response than those of previously reported models. The main anatomic sites of lymphoma were the thymus, spleen, bone marrow, and lymph nodes. Both induced and spontaneous lymphomas in the thymus and spleen stained positive for CD3 antigen, and flow cytometry detected positive CD4 and/or CD8 cells. Based on our observations and previous data, we hypothesize that mice with a B6 background are prone to lymphomagenesis.     

如何提高缉毒犬的实际工作能力

缉毒犬对各种毒品气味的分辨能力,即一头受训犬能够在各种复杂的环境中,准确地从烟、酒、食物、糖、茶、化妆品、药材以及化学物品等干扰气味中分辨出某种毒品气味,并反应正确。目前,有些地方的缉毒犬只是对单一毒品气味进行了训练：并且考虑在更为复杂的环境下的训练,即模拟训练。这种训练接近实战,要求带犬民警充分考虑到实战现场的复杂性,并以此为标准,对模拟训练中的三种形式进行合理的布局。     

浅议工作犬的个性培养

犬的个性是指犬在一定的生活环境和教育的影响下所形成的比较固定的特性。具体表现在气质、性格、智力、意志、情感、兴趣、喜好、习性等方面。虽然犬有品种、个体和性别的差异,但作为独立的个体而言都有自己独特的个性,并在日常生活中表现出来,人们通常很难将犬的个性归结为简     

Multidimensional diversity of bird communities across spatial variation of land cover in Zoige on the eastern Qinghai-Tibetan Plateau

Background: Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization, whereby the increasing similarity wo...     

Uterine Expression of WNT7A and β-catenin After Induction of Oestrus in Sheep

WNT7A and β-catenin localisations and roles in regulating periimplantation ovine conceptus development under natural estrous conditions have been elaborated.However,their locations and expression patterns have not been reported under induction of oestrus.The localisation,expression and function of WNT7A and β-catenin in the uterine tissues of the early pregnant and non-pregnant sheep on days 10,12,14,16 and 18 following artificial induction of oestrus were investigated by means of in situ hybridisation,real-time RT-PCR,immuno-histochemistry and western blotting methods.WNT7A and β-catenin mRNA and protein were both restricted to the apical surfaces of the uterine luminal epithelium (LE) and glandular epithelium (GE).In pregnant sheep,protein localisation of WNT7A and β-catenin was observed both in the endometrial LE and GE.Their staining presented on day 10,increased between day 12 and day 16,and decreased on day 18.WNT7A and β-catenin mRNA and protein expression increased initially and then decreased from day 10 to day 18,peaking on day 16,and β-catenin reaching a peak on day 18 in the uterine tissues of pregnant sheep (p0.05).By contrast,no significant changes in WNT7A and β-catenin mRNA and protein expression levels were observed from day 10 to day 18 of the oestrus cycle in the uterine tissues of non-pregnant sheep (p0.05).Additionally,WNT7A and β-catenin mRNA and protein expression levels in the uterine tissues of the early pregnant sheep were significantly higher than those of non-pregnant sheep (p0.05).Treatment of endometrial epithelial cells with WNT7A increased the mRNA expressions of β-catenin,c-myc and Cyclin D1.These results provided an underlying mechanism of periimplantation ovine conceptus development under induction of oestrus.