环青海湖盆地气候变化对草地生态环境的影响

通过分析近20年来环青海湖盆地的气候变化特征对环湖盆地草地生态环境的影响,发现环青海湖地区年平均温度升高、年蒸发量增大程度比较显著,而降水量增多不显著,且年际间变化较大,气温、地表蒸发等气象要素有向暖干化过渡的趋势。随气候变化,环湖盆地天然草地植被盖度,高度和产量均有不同程度下降,草地退化、沙化现象加剧。在不合理的人类经济活动和气候干旱化等因素的共同作用下,导致了环湖盆地地区水资源的减少和草地生态环境的沙漠化。     

青海湖流域草地时空变化特征初探

本文利用遥感手段获取流域内的草地空间分布及变化信息,结合Markov模型和动态变化度对草地状况的时空变化特征进行分析。研究表明,2013年青海湖流域草地状况良好,未退化草地占草地总面积44.68%。未退化草甸是流域内的优势草地类别,主要分布在流域中部及环湖流域西南部,动态变化度为-0.49%,时空变化稳定。2000~2013年期间流域内未变化草地占草地面积53.56%,主要分布在流域中部。草地发生退化面积略大于恢复面积,总体呈退化趋势。在近13a内草地状况变化经历了幅度较小的退化、恢复、退化的过程。草地恢复主要分布在青海湖西北及北部地区,草地发生退化主要分布在流域西北地区。     

气候变化与人类活动对川西高原草地变化相对作用的定量评估

气候变化与人类活动是草地变化两个最广泛的内在驱动力。本研究利用实际净初级生产力(NPP)和Miami气候模型模拟出潜在NPP并结合土地覆被数据来定量评估川西高原20002008年气候变化与人类活动对草地变化的相对作用。研究结果表明,川西高原20002008年草地总体上处于恢复状态,草地恢复面积占牧区草地面积比例为91.98%,草地退化面积仅为8.02%,且显著退化与极显著退化面积仅占0.1%,但退化区域相对较为集中。就草地退化而言,人为因素主导的草地退化主要集中在研究区北部,气候因素主导的草地退化主要集中在研究区中南部。就草地恢复而言,人类活动在川西高原20002008年草地恢复中起到了决定作用,如"退牧还草"工程,但集约化的管理也对工程区等局部地方的草地带来巨大的压力。本研究结果为政府保持、改进以及制定新的草地保护政策提供了依据。     

青海省草地生态环境变化态势及驱动力分析

利用青海省2个重要生态区域“三江源地区”和“环青海湖地区”1987-2004年具有代表性的草地生态观测数据和1961-2004年气象资料,并结合卫星遥感及社会调查数据,分析了2个区域草地生态环境的变化态势。主要表现为草地“黑土滩”面积不断扩大,牧草地上生物量、高度与覆盖度下降及毒杂草大量滋生,还体现在草地优势种群演化、草群结构变化、草地生产力下降等生态功能的变化上,使得草地可利用面积减少。通过研究表明,在自然因素和人为因素共同驱动力的作用下天然草地生态环境出现了不良态势,最终导致天然草地退化和载畜能力下降。并揭示了草地生态不良变化的原因、机理及生态过程,气候暖干化,加之20世纪90年代以来极端天气、气候事件的增多,是促使草地生境恶化的重要自然因素;在人为因素中,由于草畜季节不平衡、草地不均匀的放牧压力、人口增长以及生物因素等,进一步加剧天然草地生态功能的退化。     

青海湖流域气候变化对草原生态环境的影响

利用青海湖流域草原牧场气候资料和牧业生态统计资料,分析青海湖流域同德高原牧区气候变化特征及其对天然牧草生物量、草地生态环境和畜牧业的影响,发现同德地区气候变化的显著特征是:年平均气温、秋季、冬季、春季、夏季每10年升温趋势分别为0.37℃、0.23 ℃、0.50～0.88℃、0.11～0.35℃和0.10～0.33℃;年降水量每10年以10.5 mm的趋势减小,90年代是降水量最少的时期.气温年际变化趋势呈上升趋势,增温速度均大于全国增温速度.20世纪70年代之后持续偏暖.温度变化的倾向率均为正;草地年干燥指数变化呈显著上升趋势,使牧区草场产草数量和质量下降,劣等牧草、杂草和毒草的比例越来越高,草场生产力进一步下降.气象因子对草地生物量和生态环境的影响温度大于降水;降水对生态环境的影响主要表现在降水量的年际波动和年内各季节分布的差异上.当前存在的草原退化现象主要应归咎于不合理的人为活动.     

基于NDVI的藏北地区草地退化时空分布特征分析

本文以藏北地区为研究区域,基于归一化植被指数(NDVI)反演草地植被盖度,以植被盖度作为判断草地退化的标准,综合计算藏北地区2000-2010年逐年草地退化指数(grassland degradation index),定量揭示藏北地区草地退化的时空分布规律.结果表明,截至2010年,藏北地区草地退化现状仍然较为严重,退化草地的面积占全区面积的58.2%.其中,重度退化和极重度退化草地面积的比例分别为19.0%和6.5%,区域草地退化指数为1.97,接近中等退化水平.分区结果显示,藏北地区中部,东部,北部草地退化情况较为严重,均处于中等退化等级,西部地区的退化情况最轻,处于轻度退化等级.分析2000-2010年藏北地区全区及各个分区的草地退化趋势表明,只有北部地区有减缓趋势;2000-2010年间与1981-1985年间对比结果显示,重度退化及极重度退化草地面积比例上升幅度较大.2000-2010年间藏北地区平均草地退化指数为1.84,草地退化等级在轻度退化到中度退化之间波动.     

黄河首曲流域草地生态与自然环境退化成因及对策研究

近50年来黄河首曲流域草场退化、沙化,水土流失,生物多样性减少,生态系统功能弱化.分析了黄河首曲流域气候、生态观测资料及统计资料,结果表明:造成生态与自然环境退化的主要原因是气候变化和环境蠕变.黄河首曲大部分区域降水量年际变化呈下降趋势,气温年际变化呈上升趋势,增温速度均大于全国增温速度.草地年干燥指数呈显著上升趋势,20世纪80年代末至2004年明显趋于干旱化,气候变化是草地生态退化的自然诱发因素.超载过牧、滥采乱挖、人为破坏、生物链失衡等环境蠕变是造成生态退化的人为因素.二者共同作用导致黄河首曲流域草地与湿地生态与自然环境退化.控制放牧、防止滥采乱挖、建立自然生态保护区是维护该区域生态系统平衡的措施.     

藏北高寒草地生态系统现状及发展态势

以藏北那曲地区为例,分析了1955－2005年高寒草地、人口、家畜和社会经济现状与发展态势。结果表明,50年来,藏北那曲地区的年均气温上升了0.8～2.0 ℃,年均降水量增加了100～240 mm,牧业人口增加了5倍左右,家畜存栏数增加了2.9倍,牧民人均纯收入增长了94.1%,人均消费支出增长了93.1%,高寒草地退化面积占总草地面积的64.3%。以上结果说明,藏北那曲地区的气候向湿润暖温方向变化,对减缓草地退化趋势具有促进作用,而牧业人口的增加和过度放牧利用成为高寒草地退化的主要原因。因此,正确处理草地畜牧业经济发展与生态屏障保护的关系,合理利用草地资源,是目前藏北高寒草地生态系统可持续发展亟待解决的问题。     

青海省玉树县草地生态环境现状及采取的保护措施

位于青海省三江源自然保护区的玉树县随着人口的增加、资源的过度开发利用及全球气候变化的影响,正面临严重的生态环境问题,主要表现为:草场严重退化,水土流失加剧,土地沙漠化面积扩大,冰川湿地退缩、生物多样性锐减等。现已成为青海省草地退化最严重、面积最大、退化速率最快,生态问题最突出的地区之一。为了改善当地生态环境,维护国家生态安全,该地区通过禁牧、阶段性禁牧、围栏封育、季节性休牧、划区轮牧、鼠虫害防治等措施对退化的草地生态系统进行自然恢复和人工恢复重建,取得了一定的效果。     

青藏高原边缘地区草地利用现状及持续利用策略——以天祝县为例

位于青藏高原边缘地区的天祝县天然草地普遍退化,严重退化草地面积占草地总面积的34.4％。草地覆盖度、高度和产量较20世纪50年代分别下降了11.11%、41.7%和30.4%;草地群落内物种数下降,禾本科比例降低,毒杂草比例增加。草地退化主要因素包括气候干旱化、季节性超载、鼠虫危害、乱采滥挖。针对草地资源利用现状和草地生态建设的薄弱环节,提出草地资源持续利用策略。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

Smart Phone Assisted City-scale Wireless Sensor Network Deployment for Transportation System Monitoring

<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.