植物根系吸水模型研究进展

根系吸水是植物水分传输系统的最初端,直接控制着整株植物的水分传输量,进而影响植物的生命活动。对植物根系吸水的研究不仅是土壤-植物-大气连续体(SPAC)中水分运移规律研究的重要内容,同时也是水文、气候、土壤、农业、生态等多学科领域交叉研究的重点。根系吸水模型是定量化研究植物根系吸水的数学模拟工具。建立合适的根系吸水模型是准确估算植物根系吸水量的基础,这有助于弄清植物的需水特性和水分来源。本研究在总结根系吸水模型的基础上,概述了根系吸水的机理、不同研究尺度下的根系吸水模型的分类,并重点分析了实际应用较广泛的宏观根系吸水模型,且对每种模型应用的范围和局限性做出了说明。最后对现有根系吸水模型中存在的问题进行了初步分析,并对其未来研究方向和内容进行展望。     

桑苗的生长发育及其管理

桑子自播种到培育成实生苗的整个过程,大致分为:出苗期、缓慢生长期、旺盛生长期、停止生长期等四个时期,现将不同时期的情况和管理分述如下: 一、播种后到子叶出土时,通常称为出苗期。这期种子发芽要有足够的水分,适当的温度和空气。具体来讲:种子播入土壤后,即从土壤中吸取水分,吸水后可使种皮膨胀软化,     

中型,乾宁狼尾草的适宜种植区域分析

通过对中型、乾宁狼尾草野生资源分布区年积温、降水量、最高温度和最低温度等气象资料及土壤类型分析，得出这两种狼尾草生长的适宜气候区限和土壤类型。并通过对收集到的全国８９８个县（市）相应气象资料和土壤类型相似性聚类分析，规划出这两种狼尾草适宜种植区主要为长江流域及淮河以南等水热较同步的地区。     

内蒙古通辽市2011年生长季气候对农作物影响分析

根据内蒙古通辽地区境内的7个国家气象观测站2011年4—9月的气温、降水、墒情等资料,并结合农作物在整个生长过程中的生长状况,对通辽地区2011年生长季气候对农作物生长的影响进行了综合分析。结果表明,从农作物生长的整个生育期来看,播种至出苗期水分充足,土壤墒情好,春播抓苗顺利;水热匹配较为适宜,基本上是雨热同季,适宜大田作物生长发育,使农作物生长旺;夏季冰雹、洪涝、干旱等自然灾害给农牧业生产造成一定的经济损失,但由于田间管理及时到位,抗旱浇地组织及时,有效地降低了灾害损失。     

松嫩草原羊草群落水分生态的研究

采用自行设计的蒸散仪和加拿大产自动气象设备，研究了松嫩草原羊草群落的水分生态问题，结果表明，生长季晴天条件下，羊草群落的蒸散、蒸腾速率的日变化基本呈双峰曲线，但秒同月份差异显著。环境因子对群落蒸腾作用的影响是综合性的，其中太阳辐射为主导因子，并与群落的蒸腾速率呈极显著相关。温度、相对湿度、土壤含水率的日变化与群落蒸腾速率的日变化相关关系均不明显。降水量、蒸散量、土壤含水量和植物含水量构成土壤－羊草     

驼绒藜属牧草种子水分生理及幼苗耐早性研究

对驼绒藜属7份材料的种子及幼苗进行水分生理和耐旱性研究。结果表明，种子萌发时的吸水能力很强，需水量高，达到种子重量的4～7倍；种子吸水能力在种间和生态型间存在差异；种子萌发时的吸水量与其原产地的降水量呈负相关，而与种子苞片的重量呈正相关，其中生长在恶劣生境条件下的材料，苞片毛较重而密，种子吸水量较高；种子萌发吸胀吸水期的吸水速率与其活力呈负相关。供试材料的耐旱性很强，但是幼苗的耐旱性很差，主要表现在种子萌发时的需水量较高，幼苗生物量低，与其属于低营养短寿命类型的遗传特性有关；幼苗生长的最低需水量与种子的活力呈正相关，而与成熟植株的耐旱性无关。驼绒藜属牧草种子萌发和幼苗生长的水分条件是制约目前生产开基的技术关键。     

半干旱草原主要植物光能和水分利用特征的研究

在植物生长季内测定了内蒙古半干旱草原6种主要植物的光合和水分利用特征，比较了植物之间在光能和水分利用方面的差异，认为水分利用效率难以反应植物对干旱的适应性，而其倒数－水分竞争系数是较好的表征指标；植物的光能利用效率和水分竞争系数之间存在补偿关系；半干旱草原主要植物适应环境的方式不同，它们在光能和水分资源生态位上存在分离。     

天山北坡中山带天然牧草对水分条件反应特性的分析

利用新疆乌鲁木齐市牧业气象试验站2004—2009年的气象和牧草资料,研究了降水、土壤水分等水分条件对天山北坡中山带乌鲁木齐南山草原5种优势天然牧草生长高度及产量形成的影响。结果表明：天山北坡中山带中老芒麦（Elymus sibiricus）、早熟禾（Poa annua）、黄芪（Astragalus hoantchy）、老鹳草（Gterantum pratense）、千叶蓍（Achillea millefoli-um）这5种天然牧草的生长高度和产量对水分条件表现出不同的反应,老芒麦最耐旱;早熟禾和千叶蓍的抗旱性相当;黄芪对水分条件的反应最为敏感。因此,大部分牧草产量形成需水临界期是6月。这对天山北坡中山带地区草地增水抗旱工作的时间安排具有指导作用。     

4种根茎型多年生禾本科牧草抗旱生理比较研究

植物对干旱的抵抗和适应能力叫做植物的抗旱性.牧草的抗旱性是指牧草对水分胁迫的抵抗能力,包括牧草抵抗水分亏缺的能力和牧草从缺水土壤中吸水的能力.不同品种的牧草对于干旱或水分胁迫会表现出不同的抗性.     

今年我国北方大部分草原提前返青

正农业部草原监理中心采取地面观测、卫星遥感和结合气象资料分析的方法,对全国草原牧草返青状况进行了监测分析。结果显示:与常年相比,3~5月全国大部分草原地区气温较高,土壤墒情较好,水热条件总体有利于牧草返青生长。截至5月20日,全国92%的草原已经返青,与常年相比我国北方大部分草原提前返青。一、气象状况入春以来,我国大部分草原地区气温较常年高1~2℃,良好的热量条件有利于积雪融化、土壤解冻和牧草萌     

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.     

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.     

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.     

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.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.