生物结皮对高寒退化草地植物群落的影响

生物结皮在各类生态系统中扮演着重要的角色,具有调控土壤水分,养分含量与侵蚀敏感性等作用,并可直接或间接地影响地上植物群落,但对植物群落发展存在促进还是抑制作用尚不清楚。本研究于2017年在青海贵南县森多镇高寒草原,设置大样方,对生物结皮种类和分布格局进行调查。结果表明：在青藏高原高寒退化草地生态系统中,生物结皮的存在显著影响了植物的群落结构,降低了杂草的比例;苔藓生物结皮的盖度与草本植物盖度在初级发育阶段的生物结皮（地衣和苔藓共存）的样方中呈显著正相关关系（P<0.05）,在高级发育阶段的生物结皮（仅有苔藓结皮存在）的样方中正相关关系极显著（P<0.01）。由此可见,生物结皮是高寒草地生态系统的重要组成部分,有调节高寒退化植物群落的结构和功能的作用。     

Pregnancy-related diabetes mellitus in two dogs

CASE SUMMARIES: Two cases of diabetes mellitus occurring in bitches in association with pregnancy are reported. In the first case, a bitch with suspected acromegaly developed diabetes mellitus within 2 weeks of the due date. Despite insulin therapy, euglycaemia was not achieved. Tw o live, small pups were delivered by elective Caesarean section but died within 2 days. Signs consistent with acromegaly resolved but diabetes mellitus was permanent in the bitch. In the second case, diabetic ketosis with severe gastrointestinal disease was diagnosed 2 days after Caesarean section was performed due to dystocia. The pups delivered all died within 5 days. The bitch recovered fully from diabetes mellitus within 2 weeks and has remained euglycaemic without insulin for a period of at least 18 months.

CLINICAL RELEVANCE: These two cases demonstrate that diabetes mellitus can occur in association with pregnancy in dogs, that diabetic ketosis can occur during transient diabetes mellitus in dogs, and suggest that acromegaly may occur during pregnancy-related dioestrus in dogs. The scarcity of previous reports of this nature, however, suggests that such cases are unusual.

Lack of prompt resolution of hyperglycaemia may result in secondary diabetes mellitus becoming permanent. Management should focus on immediate insulin therapy or ovariohysterectomy to minimise this risk. Even mild hyperglycaemia should not be ignored during pregnancy. The insulin antagonistic effects of pregnancy, stressful illness, surgery and dystocia can be enough to result in diabetic ketosis in the absence of permanent insulin deficiency. Maternal hyperglycaemia may contribute to adverse fetal outcomes in dogs but further study is required regarding the nature of the risk.     

低温在诱导油桃芽解除休眠过程中对代谢的影响

果树温室栽培时常出现萌芽率低，萌芽开花延迟，花器官发育差，座果率低等问题。调查了分批移入人工气候室的“NJ72”油桃萌芽率，以确定其休眠解除时间，试验结果表明“NJ72”油桃于1月中旬结束休眠，不同温度处理对“NJ72”油桃休眠期代谢的影响不同，低温促进花芽内H2O2的积累，同时促进过氧化氢酶（CAT）、超氧物歧化酶（SOD）、过氧化物酶（POD）活性的提高，低温处理使花芽呼吸速率增加，其中磷酸戊糖途径（PPP）代谢增加，糖酵解（EMP）降低，而三羧酸循环（TCA）代谢波动较小，葡萄糖－6－磷酸（G－6－PDH）脱氢酶活性也有所增加。     

Agreement among three different equine venipuncture sites with regard to measurement of packed cell volume and total solids

The primary objective of this study was to determine the agreement between the packed cell volume (PCV) and total solids (TS) values in blood collected from the jugular vein (JV) in comparison with the cephalic vein (CV) and the transverse facial venous sinus (TFVS) in healthy adult horses. A total of 72 samples were taken from 24 horses. We found high agreement that reflects no clinically relevant differences between the PCV and TS values obtained from the CV or the TFVS in comparison with the JV in standing healthy adult horses.     

Rotation and Magnetism of Earth's Inner Core

Three-dimensional numerical simulations of the geodynamo suggest that a super- rotation of Earth's solid inner core relative to the mantle is maintained by magnetic coupling between the inner core and an eastward thermal wind in the fluid outer core. This mechanism, which is analogous to a synchronous motor, also plays a fundamental role in the generation of Earth's magnetic field.     

Determination of the Trace Element Contents in Plants Using Atomic Absorption Spectrophotometer

The aim of the study is to investigate the contents of trace dement Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite fumace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respec-tively; Cd in burdock stem, skin and leaf are 0. 160 0, 0.300 0, O. 140 0 isg/g, respectively; Cd in burdock stem, skin and leaf are 2.020, 3.960,2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 la.g/g, respectively; for Cd are 0.181 0 and 0.202 0 μg/g, respec-tively ; for Pb are 3.572 and 4.021 μg/g, respectively. In garlic, $e, Cd and Pb are 73. 900 O, 6.900 0 and 0.390 0, respectively. All the standard devi-ations of measured results are below 2.3%, recovery rate are from 99% to 101%.     

玉树州特色中藏药发展对策及前景分析

根据玉树特殊的地理环境,气候特点,特色中藏药自然资源优势及其形态特征,提出了玉树特色中藏药发展对策。     

GIS支持下1985-2000年北京林地数量、质量演变与驱动分析

在收集、研究1985年、1995年、2000年北京土地覆盖类型的图像和矢量数据的基础上,提取不同时间段北京林地相关的数据信息,并从多个角度分析研究区内各类林地与其它土地覆盖类型之问相互转化和各类林地之间的演替情况,得出2000年北京各类林地面积总量与1985年相比有少量增加,但林地总体质量水平却有下降趋势;并从经济社会发展以及国家及北京的生态环保政策等方面,对林地演变的驱动因子进行分析.     

Detection of Water Buffalo Sex Chromosomes in Spermatozoa by Fluorescence in situ Hybridization

In order to identify X‐ and Y‐bearing spermatozoa in water buffalo by fluorescence in situ hybridization (FISH), some available probes of closely related species were examined. An X‐ and Y‐specific probe set, made from flow sorted yak chromosomes, labelled in somatic metaphases of water buffalo the whole X and Y, respectively, except their centromere regions. A cattle Y‐chromosome repeat sequence (BC1.2) showed strong signal on the telomere region of the buffalo Y‐chromosome, demonstrating the evolutionary conservation of this locus in water buffalo. In hybridization experiments with spermatozoa from five buffaloes, the yak X‐Y paint set demonstrated clear signals in more than 92% (46.8% X and 45.8% Y) of the cells. Using the cattle Y‐chromosome specific BC1.2 probe, clear hybridization signal was detected in more than 48% of the cells. Statistical analysis showed that there was no significant difference between bulls or from the expected 50 : 50 ratio of X‐ and Y‐bearing cells. The probes presented here are reliable to assess separation of X‐ and Y‐bearing spermatozoa.     

Reproductive performance of Thoroughbred mares on six commercial stud farms

The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the first served oestrous cycle (77.8%) than in mares that needed two served oestrous cycles to become pregnant (65.4%). Of all diagnosed pregnancies, 19.5% were not completed. Pregnancy loss was lower (P < 0.05) in maiden (12.4%) than in barren (19.7%) or foaling (20.9%) mares. Twins were diagnosed in 7.8% of all pregnancies. If one conceptus was lost without external interference, 84.1% of pregnancies went to term. If one conceptus was manually crushed, 55.9% of pregnancies were maintained. If prostaglandin was used to terminate twin pregnancies, 60% of mares so treated produced foals the following year.