试论福建省国营林场分类管理

本文分析了福建省110个国营林场的类型、目前管理体制、管理办法及存在的问题。指出了目前国营林场管理办法中存在着种种弊端,跟深化林业改革很不适应,必须改革和完善国营林场管理机制,理顺“省办地管县监督”的管理体制,实行分类指导。本文就分类管理的依据,原则和实施办法进行了探讨,并提出了一些建议。     

An investigation of uncertainty in field habitat mapping and the implications for detecting land cover change

Land cover data for landscape ecological studies are frequently obtained by field survey. In the United Kingdom, temporally separated field surveys have been used to identify the locations and magnitudes of recent changes in land cover. However, such map data contain errors which may seriously hinder the identification of land cover change and the extent and locations of rare landscape features. This paper investigates the extent of the differences between two sets of maps derived from field surveys within the Northumberland National Park in 1991 and 1992. The method used in each survey was the Phase 1 approach of the Nature Conservancy Council of Great Britain. Differences between maps were greatest for the land cover types with the smallest areas. Overall spatial correspondence between maps was found to be only 44.4%. A maximum of 14.4% of the total area surveyed was found to have undergone genuine land cover change. The remaining discrepancies, equivalent to 41.2% of the total survey area, were attributed primarily to differences of land cover interpretation between surveyors (classification error). Differences in boundary locations (positional error) were also noted, but were found to be a relatively minor source of error. The implications for the detection of land cover change and habitat mapping are discussed.     

The metabolism of R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene] in rat hepatocyte suspensions

The metabolism of R-20458 [(E)-6,7-epoxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene] by rat hepatocytes has been analyzed and compared with that of juvenile hormone I [methyl-(E,E)-cis-10,11-epoxy-7-ethyl-3,11-dimethyl-2,6-tridecadienoate] under identical conditions. The metabolism of R-20458 is characterized by the predominance of NADPH-dependent cytochrome P-450 and epoxide hydrolase reactions; whereas, JH I is metabolized mainly by carboxylesterase, epoxide hydrolase, and glutathione S-transferases. The metabolites of R-20458 have been shown to correspond to (E)-6,7-epoxy-1-(4-hydroxyethylphenoxy)-3,7-dimethyl-2-octene; (E)-6,7-epoxy-1-(4-acetylphenoxy)-3,7-dimethyl-2-octene; (E)-6,7-dihydroxy-1-(4-ethylphenoxy)-3,7-dimethyl-2-octene; and, (E)-6,7-dihydroxy-1-(4-acetylphenoxy)-3,7-dimethyl-2-octene. The production of the α-hydroxyethyl, p-acetylphenoxy, and acetylphenoxy-6,7-diol metabolites is markedly inhibited by SKF 525-A. No dramatic effects are produced by diethylmaleate and 1,2-epoxy-3,3,3-trichloropropane.     

The effect of some Frescon analogs on the aquatic snail,Lymnaea stagnalis: II. Correlation of neurotoxicity to Molluscicidal effectiveness

Although the molluscicide Frescon is a strong neurotoxin to the Lymnaea stagnalis central nervous system in vitro, it is probable that the exposure of the whole animal to this molluscicide fails to result in central nervous system abnormalities: Frescon does not appear to reach the brain in sufficient quantity to disrupt its normal activity. However, only those Frescon analogs found to be neurotoxic were molluscicidal, suggesting some related mode, if not site, of action. Frescon and its analogs may act by affecting excitable tissues other than the nervous system (e.g., the snail musculature) by altering certain functional and/or structural membrane properties.     

Effects of chlordimeform on mitochondria from eggs of Spodoptera littoralis

Mitochondria were isolated from eggs of Spodoptera littoralis. With succinate (+pyruvate) as substrate, respiratory control ratios between 1.70 and 2.54 were obtained. Uncouplers and the energy transfer inhibitor oligomycin influenced these mitochondria in the well-known manner. The uncoupling activity of chlordimeform in vitro was very weak and decreased with increasing age of the eggs. Electron transport in mitochondria from chlordimeform-treated eggs was not uncoupled. Therefore, it is concluded that the ovicidal effect of this pesticide is not due to its uncoupling effect.     

The effect of phosphine on the absorption and circular dichroic spectra of cytochrome c and cytochrome oxidase

The interaction of phosphine with purified cytochrome c and cytochrome oxidase was studied by absorption and circular dichroic spectrometry. Treatment of cytochrome oxidase with phosphine yielded absorption spectra in both the visible and Soret region that were similar to that produced by dithionite. Striking changes in the circular dichroic spectra were also recorded, sugesting that a valence change of the heme iron was accompanied by a conformation change of the prosthetic group.Phosphine treatment of cytochrome c also yielded spectra similar to those produced by reduction with dithionite suggesting a valence change of the heme iron. However, both the time necessary for complete reduction and the concentration of phosphine necessary for this effect suggest that, in comparison with cytochrome oxidase, cytochrome c was relatively insensitive. Reduction of cytochrome oxidase by phosphine had only a very minor effect on the intrinsic dichroic spectrum suggesting little effect on the polypeptide chains.The persistence of a component after reduction by phosphine and the subsequent reduction of this component by dithionite suggests that phosphine primarily reduced only one comonent of the cytochrome aa₃ complex. The failure of EDTA and fluoride, which are known ligands of cytochrome a₃ to affect the reduction of cytochrome aa₃ by phosphine, as well as the occurrence of a 436-nm isosbestic point of the ferric-ferrous absorption spectra suggests that phosphine reduced primarily cytochrome a. However, it is argued that a slow reduction of cytochrome a₃ cannot be ruled out.     

新疆退牧还草工程建设与管理的探讨

草地是发展畜牧业的重要基础,退牧还草工程是恢复、更新天然草地和保护生态环境的重要手段。本文就新疆实施退牧还草工程中所出现的一些问题进行了探讨。     

早熟春甘蓝新品种春冠的选育

春冠亲本之一493是将国外引进的资源96011、9502杂交后，经系统选育，采用露地越冬栽培加大耐先期抽薹性的选择强度选育出的自交不亲和系。另一亲本711是从国外引进的资源B-21经多代自交选育出的自交不亲和系。该品种耐寒，露地越冬不易先期抽薹，早熟，叶球尖桃形，肉质脆嫩，品质佳。单球质量1.5kg左右，每667m^2产量3500kg左右。在南方地区可露地越冬栽培，已在长江流域示范推广。     

Prediction of breeding values for osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints, and pathologic changes in the navicular bones of Hanoverian Warmblood horses

The results of a standardised radiological examination of 5928 Hanoverian Warmblood horses selected for sale at auction were used to predict relative breeding values (RBV) in the 23,662 horses included in the last four generations of the probands' pedigrees. The distribution of the RBV was investigated in the whole four-generation pedigree, in the probands and in those stallions that contributed at least three offspring to the probands. The RBV of the probands' sires were further compared with the officially published performance-based relative breeding values, i.e., total indices dressage (TID) and jumping (TIJ). The sires' level of dressage indices was considerably higher (mean TID=110) than of the jumping indices (mean TIJ=98). Total indices radiographic findings (TIR) were calculated for the sires with varying weighting given to the individual RBV. In each case, this resulted in a mean TIR of 99. Finally, total indices were derived from TIR and TID and/or TIJ in order to develop different selection schemes for all-purpose breeding and for breeding focused on dressage and show jumping. All breeding values under consideration increased by between 1% and 19% when radiographic findings were weighted with between 30% and 60% complementary to the corresponding performance parameters, and when only sires were selected with above average total indices. At the same time, the prevalences of the radiographic findings investigated here were lowered by up to 10% each. When only one radiographic finding was considered at a time, the maximum attainable response to selection was a 16-23% increase in the relative breeding values and a relative decrease in prevalences of radiographic findings of between 31% and 52%. The results of this study indicate that it is possible in horse breeding to consider simultaneously health and performance traits. Medical data should be included in the prediction of breeding values in order to improve the radiological status of today's riding horses.     

工厂化猪场不同猪群死亡率与季节的关系初探

通过对哺乳仔猪群、保育群、育成群各月死亡率的统计分析发现,冬季低温对哺乳仔猪群、保育群死亡率的影响远远大于夏季高温的影响。冬季低温对保育群的死亡率影响最大,而对育成群几乎没有影响。夏季高温对不同猪群的死亡率有不同程度的影响力。不同猪群对温度反应的快慢、强度及持续期各不相同。