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1.
以2008年美国总统大选为切入点,从反恐与伊拉克战争、经济与贸易、非法移民问题以及教育、司法、传媒等角度,着眼此次美国总统选举的选情,分析其背后错综复杂的政治经济利益、文化冲撞与交锋,前瞻美国社会的变迁。笔者认为,近年来美国政治和社会经历了少有的变革,政治经济上的失策及大众的不安造成了美国社会的巨大分化与不稳定。由此带来的美国内外政策和全球战略的重大调整与转变必将在此次美国总统选举的结果中得到体现和印证。它们将在很大程度上决定今后十年美国内政外交的走势,对美国自身的力量涨落、政策取向和国际格局带来重大和深远的影响。  相似文献   

2.
本研究旨在探索L1(Long Interspersed Nucleotide Element 1)和RTE(Retrotransposable Element)在牛和猪基因组中的分布、起源及传递方式和相互间作用。使用软件Repeat Masker和Censor探测了牛和猪基因组中L1和RTE的含量及在各条染色体上的分布。结果,L1在牛和猪基因组中的平均含量分别为7.89%和10.64%,平均长度分别为529和608 bp;RTE在牛基因组中的平均含量为11.83%,平均长度为433 bp。猪基因组未发现RTE序列。牛和猪基因组中的L1共有序列各自分为6个家族和14个亚族。牛和猪基因组中的L1含量均随着染色体GC含量的升高而降低,牛基因组中的RTE含量也呈此变化趋势。牛基因组中RTE序列不是从祖先物种纵向传递而来,而是通过横向传递来源于其它未知物种。牛和猪的L1内部、牛RTE内部以及牛基因组中L1和RTE之间存在选择性进化现象。  相似文献   

3.
论生态环境与畜禽健康——环境污染对畜禽健康的影响   总被引:4,自引:2,他引:2  
由于工业生产排放的废水、废气和废渣数量日益增多以及农牧业生产大量使用农药、化肥、兽药和饲料添加剂,环境污染物和有毒有害物质对畜禽生产性能和畜产品品质的影响日益严重,本文论述了环境污染物对畜禽毒害的形式和环境污染物的剂量效应与毒性测定方法,对于消除环境中有害物质,生产绿色食品具有重要的意义。  相似文献   

4.
AIM: To compare liver copper, selenium and vitamin B12 concentrations in red deer of farmed and feral origin. METHODS: Liver samples were collected from red deer at a South Island deer slaughter premise and a game packing house in November 2000. The site of origin and age of each animal were recorded. A subsample of 107 livers was selected (n=5-10 per site of origin and age category) from farmed deer from central Canterbury, Nelson and Westland, and from feral deer from north, central and south Westland. Samples were analysed for copper, selenium and vitamin B12 concentrations and reported on a wet-matter basis. RESULTS: Mean liver copper concentrations for farmed and feral yearlings were 267 and 889 micromol/kg, respectively, and for farmed and feral adults were 206 and 677 micromol/kg, respectively. Liver copper concentrations were lower for farmed than for feral deer (p<0.001) and for feral adults than for feral yearlings (p=0.002). Mean liver selenium concentrations in farmed and feral yearlings were 2050 and 1539 nmol/kg, respectively, and in farmed and feral adults were 1938 and 1625 nmol/kg, respectively. Liver selenium concentrations varied significantly between regions and overall, farmed deer had higher liver selenium concentrations than feral deer (p=0.04). Mean liver vitamin B12 concentrations in farmed and feral yearlings were 456 and 742 nmol/kg, and for farmed and feral adults were 428 and 869 nmol/kg, respectively. Liver vitamin B12 concentrations were lower for farmed than for feral deer (p<0.001). CONCLUSION: Feral deer had higher liver copper and vitamin B12 concentrations and lower liver selenium concentrations than farmed deer in the regions studied.  相似文献   

5.
陇中干旱区草粮兼顾型生态农业模式构建   总被引:2,自引:0,他引:2  
陇中黄土高原丘陵区具有旱灾频繁、地形破碎、水土流失严重等特点,是我国主要的生态脆弱区。在国家生态文明建设的时代背景下,如何实现生态保护前提下的绿色经济发展之路,这不仅是技术革命,更是理念变革。分析了陇中干旱农业系统面临的传统粮草牧轮作方式多样性遗弃、农业生态环境持续变差、年轻农业劳动力外流等问题,提出将传统农耕文明与现代科技文明有机融合,深度挖掘区域自然禀赋,探索了人与自然和谐的草粮兼顾型生态农业的发展理念、基本思路和发展模式:1)坚持环境生态化、农产品商品化、农村文化现代化的系统性理念;2)奉行让餐桌指挥农田,农田为餐桌服务,企业带动农民合作社,使生产、加工和销售融合发展的理念;3)在农业土地经营中,坚持生态保护与生态建设优先,田园综合经营管理,通过粮改饲和旱作农业技术革新,实现杂粮与牧草轮作种植,建立粮、草、林、畜、禽协同发展的农作制度,保障社会对农产品多元化和食品安全;4)依托乡土食材消费需求拉动,加工企业与农民合作社联营,农产品标准化订单种植生产,市场信息反馈,促进农业要素的重组耦合,实现农产品的增值提效;5)培训扶持懂技术、会管理的能人,牵头领办农民合作社,组织土地流转,设计田间生产。  相似文献   

6.
反刍家畜瘤胃及肠道微生物处于一个复杂的微生态系统,其多样性及营养代谢与该系统中的各项因素存在紧密联系。了解反刍家畜瘤胃及肠道微生物多样性变化和营养代谢机制,是通过人为干预手段改善动物福利、提高动物生产效率、提升动物产品质量、减少温室气体排放的基础。关于反刍动物瘤胃及肠道微生物多样性及营养代谢与单个环境因子的关系得到了广泛的研究并取得了一些进展,对指导生产实践和保护环境起到了一定作用。综述了近年来国内外反刍家畜瘤胃及肠道微生物多样性,以及微生物与宿主动物、日粮结构、环境因子相互作用及机制方面的研究进展,以期为探索瘤胃及肠道微生物在反刍动物营养代谢中的作用及其机制提供参考。  相似文献   

7.
【目的】 筛选鸡胚胎早期发育期间背部皮肤上皮和间充质中调控毛囊生长的关键基因、生物过程和信号通路,为了解鸡胚胎早期发育期间毛囊生长的分子机制提供参考。【方法】 从GEO数据库中下载基因芯片GSE62882数据集,采用R语言limma包对数据集进行差异分析,分别筛选出胚胎期第7和9天皮肤上皮和间充质差异基因以及皮肤上皮和间充质共同上下调基因,通过STRING在线数据库对差异基因和共同上下调基因进行蛋白互作网络分析,用Cytoscape 3.8.2软件进行可视化,运用R语言中的clusterProfiler程序包对差异基因和共同上下调基因进行GO功能和KEGG通路富集分析。【结果】 皮肤上皮在胚胎期第7和9天共筛选出626个差异基因,获得189条相互作用关系、10个生物过程和4条信号通路;皮肤间充质在胚胎期第7和9天共筛选出690个差异基因,获得326条相互作用关系、10个生物过程和3条信号通路;皮肤上皮和间充质在胚胎期第7和9天共同上调基因26个,共同下调基因48个,共同上下调基因存在34条相互作用关系,主要富集在Wnt信号通路上。【结论】 本研究从鸡胚胎期第7和9天皮肤上皮和间充质中筛选到共同上调基因26个,共同下调基因48个,这些基因主要富集在Wnt信号通路上,为探究上皮和间充质在毛囊生长发育中的作用机制提供理论参考。  相似文献   

8.
Disposition kinetics of danofloxacin and ciprofloxacin in broiler chickens.   总被引:3,自引:0,他引:3  
Disposition kinetics of danofloxacin and ciprofloxacin were studied in broiler chickens following intravenous, intramuscular and oral administration in a single dose of 5 and 10 mg/kg-1 body weight respectively. In addition, tissue distribution and residual pattern of both drugs were determined. The maximum serum concentration (Cmax) after intramuscular and oral administration were 1.03 and 0.55 mu/ml for danofloxacin and 2.92 and 1.24 mu/ml for ciprofloxacin attained at 0.8 and 2.43 and 0.55 and 1.27 hours for danofloxacin and ciprofloxacin respectively. The volume of distribution and systemic bioavailability were higher for danofloxacin (Vdss 2.21 L/kg and F% 96.56 and 81.4%) as compared with ciprofloxacin (Vdss 1.41 L/kg and F% 75.5 and 29.4%). Data relating to intravenous injection for both drugs were analyzed using a two compartment open model curve fit. Danofloxacin and ciprofloxacin were not detected in the serum of broilers at the 5th and 3rd day respectively following the drugs withdrawal while were detected in liver, kidneys, spleen and lungs. Danofloxacin completely disappeared from all tissues at the 13th day after stopping of the drug medication but ciprofloxacin disappeared after 5 days only.  相似文献   

9.
水貂多态蛋白位点与经济性状相关的研究   总被引:1,自引:0,他引:1  
通过建立一般线性模型对美国短毛黑、大连金州黑和左家型水貂遗传标记的筛选,方差分析表明,Pi-3对左家型水貂皮张长度有显著影响,Pi-3位点与美国短毛黑针绒毛长度比之间存在显著相关,Est是对金州黑水貂体重影响较大的位点,Po是对金州黑水貂针绒毛长度比影响较大的位点,Po和Est对金州黑水貂绒毛长度有显著影响。最小二乘均数结果表明,左家型水貂Pi-3的AA型与AB型间皮长差异显著,美国短毛黑中Pi-3的AA型与AB型间针绒毛长度比差异显著,金州黑水貂Est的AB和BB型体重之间也有显著差异,金州黑水貂Po的AA型与AB型的针绒毛长度比有显著差异,金州黑水貂Po的AA型与BB型和Est的AB和BC基因型之间的绒毛长度也有显著差异。  相似文献   

10.
Canine and feline dermatomycosis is the common skin disease in small animal,which not only affects the appearance of the canine and feline, but also leads to itching or pain, and even increases the risk of dog and cat owners suffering from dermatomycosis. Dermatomycosis is harmful to health of animals and human beings. The dermatomycosis is difficult to identify, has long treatment cycle and high recurrence, and affected by regional or/and environmental factors, lead to its prevalent and brought great difficulties to the clinical diagnosis and treatment. Canine and feline dermatomycosis could be diagnosed according to illness history survey, clinical symptoms, isolation and identification of pathogens and histopathological examination. In order to curing canine and feline dermatomycosis effectively, systemic therapy combined with topical administration, scientific and rational use of antibiotics, and improvement of animal feeding management should be carried.  相似文献   

11.
小尾寒羊和大尾寒羊能量与蛋白质代谢规律研究   总被引:4,自引:0,他引:4  
选用小尾寒羊和大尾寒羊200只.分妊娠期、泌乳期、哺乳期和生长期4个不同生理阶段.系统研究了蛋白质和能量代谢规律。研究过程采用了饲养对比试验8次.消化代谢试验16次.低氮日粮平衡试验4次,气体能量代谢试验6次.比较屠宰试验4次,并采用瘤胃瘘管技术、血液生理生化指标测定等技术。制定出小尾寒羊和大尾寒羊的能量维持需要、各级有效能转化效率、畜体总产热和绝食代谢产热等基础代谢参数89个.粗蛋白质和可消化粗蛋白质维持需要、不同生理状态和生产水平下的粗蛋白质、可消化粗蛋白质生产需要、以及内源尿氮和代谢粪氮等蛋白质代谢参数58个。  相似文献   

12.
骨骼构成机体结构的基本框架,骨形成和骨吸收的动态平衡关系到骨骼健康。钙和磷是动物体骨骼生长发育过程中重要的矿物质元素,机体对其吸收与调控直接影响骨代谢过程。血钙和血磷水平的变化,改变了机体相关调节激素的分泌,而这些激素可影响骨骼发育,因此,钙、磷代谢与骨骼健康紧密相关。综合国内外钙、磷代谢和骨代谢等方面的研究,从钙、磷的吸收和代谢,含量和比例以及钙磷代谢相关调节激素对骨骼发育的调控机制等方面进行综述,旨在为后续动物钙、磷代谢和骨骼之间调控的研究提供参考。  相似文献   

13.
肉鸡腹水症心肝肺显微和超微结构研究   总被引:4,自引:1,他引:3  
运用光镜、电镜技术,观察了肉鸡腹水症自然发病鸡心、肝、肺的显微和超微结构。肺呈弥散性充血和水肿,三级支气管和肺房扩张,平滑肌肥大,软骨样和骨样小结节病灶明显增多,呼吸毛细管上皮细胞内出现大量空泡,肺气-血屏障结构受破坏。心脏肥大,右心扩张,心肌纤维间淤血、水肿,充满大量炎性细胞和结缔组织细胞。心肌变性坏死,肌原纤维断裂,有的横纹消失。肝充血肿大,表面被覆一层灰白色或淡黄色胶冻样物。肝血窦扩张,肝细胞索排列紊乱,肝细胞界限不明显,肝细胞质内的线粒体嵴模糊不清  相似文献   

14.
不同下垫面每次降雨水土流失特征及影响因素分析   总被引:5,自引:0,他引:5  
研究了不同下垫面每次降雨产流产沙特征及其与降雨、降雨前期条件的内在关系。结果表明,百喜草覆盖和敷盖处理的产流产沙均远小于对照处理,相对对照处理,减水率在95%以上,减沙率在99.9%以上。影响百喜草覆盖和敷盖处理产流、产沙的最主要因素为降雨量,其次为降雨历时。同时,在影响百喜草覆盖和敷盖处理产沙因素中,产流影响显得更密切,也更直接。而对于对照处理,影响产流、产沙的最主要因素为降雨量和降雨强度,而且降雨量主要影响产流,降雨强度则主要影响产沙。  相似文献   

15.
在中兽医方剂组方配伍中蕴含着丰富的相互对应思想,具体表现在方剂配伍中的阴与阳、气与血、脏与腑、升与降、散与收、泻与补、寒与热、润与燥、生与克、行与守十大相对关系,积极探讨中兽医方剂配伍中的相互对应关系,有助于提升中兽医方剂组方配伍规律的进一步认识,对兽医临证立法处方用药有着重要的指导意义。  相似文献   

16.
动物福利是国内外学者热议的话题,也是标准化生产和畜产品质量安全的重要影响因素。动物福利体现在饲养、养殖环境、健康、行为等各个环节中。马驴作为中国重要的草食家畜,在精准扶贫和乡村振兴中发挥着重要作用。该文阐述了马驴养殖的经济价值,对中国马驴养殖福利现状和动物福利在马驴养殖中的相关影响因素进行探讨,为宣传、提升马驴养殖福利提供一些参考。  相似文献   

17.
Vascular Endothelial Growth Factor (VEGF) and its receptor KDR are involved in the regulation of angiogenesis and are up-regulated in a number of tumours in humans and in particular, breast cancer. We therefore evaluated the prognostic potential of the angiogenetic process in feline and canine mammary carcinomas by the immunohistochemical assessment of VEGF expression and micro vessel density (MVD) quantification and examined the interplay between VEGF and KDR. These variables were related to some relevant clinicopathological parameters and to overall survival (OS). VEGF and KDR expression were evaluated in epithelial, stromal and endothelial compartments in order to identify autocrine and/or paracrine loops. In dogs an increased VEGF expression did not show any statistical correlation with the clinicopathological parameters examined and was not correlated to a poorer prognosis. MVD was found to be significantly correlated to the histologic type (P=0.04), tumour grading (P=0.02), and to the OS (P=0.01). In cats VEGF expression was significantly correlated to tumor grading (P=0.01) and OS (P=0.03), while no significant associations were found between MVD and the other parameters. VEGF and KDR were found to be detected on the epithelial, and/or endothelial and/or stromal cells of the carcinomas in both species, suggesting indications for some possible autocrine and paracrine loops. Our results encourage further studies on the possible prognostic role of VEGF and MVD in canine and feline mammary tumours and on the role of growth factors and their receptors in promoting tumour proliferation and an "angiogenetic shift". The VEGF/KDR system may play a role in malignant transformation and tumor progression.  相似文献   

18.
A large number of empirical and mechanistic simulation models and decision support tools have been produced for rangelands. Collectively, these models have considerably increased our fundamental knowledge and understanding of the dynamics of ecosystem functions, processes, and structure. We explore three areas where models for rangeland management are often challenging for land managers and enterprise-level decision making: 1) coping with spatiotemporal and climatic variability in implementing scenario forecasting, risk assessments, and adaptive management; 2) addressing outputs of multiple ecosystem goods and services and determining whether they are synergistic or competitive; and 3) integrating experimental and experiential knowledge and observations into decision making. Increasing the utility of models for rangeland management remains a key frontier and a major research need for the modeling community and will be achieved less by further technical advances and model complexity and more by the use of existing topoedaphic databases, the capacity to readily incorporate new experimental and experiential knowledge, and the use of frameworks that facilitate outcome-based, adaptive decision making at the enterprise level with associated economic considerations. Opportunities exist for increasing the utility of models for decision making and adaptive rangeland management through better matching of model complexity with enterprise-level, decision-making goals. This could be accomplished by incorporating a fundamental understanding of herbivory, fire, and spatiotemporal interactions with weather patterns that affect multiple ecosystem functions. Most important, effective models would allow land managers in a changing and variable climate to 1) evaluate trade offs in producing multiple goods and services, 2) optimize the application of conservation practices spatially (comparing costs and benefits accrued across different timescales), and 3) incorporate manager capacity, including experience, skills, and labor input.  相似文献   

19.
关于构建蚕桑药食用途育种技术体系的思考   总被引:8,自引:2,他引:6  
在分析现行蚕、桑育种技术的基础上,以蚕、桑资源的药用和食用价值开发为着眼点,提出了以蚕、桑资源的食用营养成分、药理活性及其物质基础为依据,以药用活性成分及食用营养成分为首要选育目标,选育一批药用价值和营养价值高且成分优、抗性强、产量高、口感好的蚕、桑新品种,以拓展现有的蚕、桑育种模式,构建蚕、桑药食用途育种技术体系的新设想。  相似文献   

20.
Acute phase proteins in serum and milk from dairy cows with clinical mastitis   总被引:17,自引:0,他引:17  
The serum concentrations of haptoglobin, serum amyloid A and alpha1 acid glycoprotein were determined in serum collected from healthy dairy cows and cows with clinical mastitis, graded as mild (clots in milk) or moderate (clots in milk and visible signs of inflammation in the mammary gland/s) to assess their relative diagnostic value in detecting the disease. The concentrations of haptoglobin and serum amyloid A were also measured in milk collected from infected and uninfected quarters. The concentrations of haptoglobin and serum amyloid A were higher in the serum and milk from the cows with mild or moderate mastitis. The diagnostic value of haptoglobin in differentiating between healthy animals and those with mastitis gave sensitivities and specificities of 82 per cent and 94 per cent respectively with serum and 86 per cent and 100 per cent with milk. The diagnostic value of serum amyloid A in differentiating between healthy animals and those with mastitis gave sensitivities and specificities of 83 per cent and 90 per cent with serum and 93 per cent and 100 per cent with milk. The diagnostic value of serum alpha1 acid glycoprotein in differentiating between healthy animals and those with mastitis gave sensitivities and specificities of 62 per cent and 91 per cent.  相似文献   

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