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61.
A multi-scale assessment of human and environmental constraints on forest land cover change on the Oregon (USA) coast range 总被引:3,自引:0,他引:3
Human modification of forest habitats is a major component of global environmental change. Even areas that remain predominantly forested may be changed considerably by human alteration of historical disturbance regimes. To better understand human influences on the abundance and pattern of forest habitats, we studied forest land cover change from 1936 to 1996 in a 25000 km2 landscape in the Oregon (USA) Coast Range. We integrated historical forest survey data and maps from 1936 with satellite imagery and GIS data from 1996 to quantify changes in major forest cover types. Change in the total area of closed-canopy forests was relatively minor, decreasing from 68% of the landscape in 1936 to 65% in 1996. In contrast, large-conifer forests decreased from 42% in 1936 to 17% in 1996, whereas small-conifer forests increased from 21% of the landscape in 1936 to 39% in 1996. Linear regression models were used to predict changes in the proportion of large conifer forest as a function of socioeconomic and environmental variables at scales of subbasins (mean size = 1964 km2, n=13), watersheds (mean size = 302 km2, n=83), and subwatersheds (mean size = 18 km2, n=1325). The proportion of land in private ownership was the strongest predictor at all three spatial scales (partial R2 values 0.57–0.76). The amounts of variation explained by other independent variables were comparatively minor. Results corroborate the hypothesis that differing management regimes on private and public ownerships have led to different pathways of landscape change. Furthermore, these distinctive trajectories are consistent over a broad domain of spatial scales. 相似文献
62.
通过对生产关系创新理解,准确把握马克思的资本主义生产关系本义,解释了马克思“重建个人所有制”真实意思是恩格斯的重新建立消费资料个人所有,坚持了马恩列思想的严肃性和一致性;我国必须坚持和发展马克思主义基本原理,要学会在不同的时代和历史条件下,应用马克思主义基本原理即马克思主义中国化. 相似文献
63.
李永安 《云南农业大学学报(自然科学版)》2014,(3):11-15
学界对于农地产权问题的相关争论,多集中于农地公有制还是私有制更能促进公平与效率.本研究梳理了农地产权问题的不同观点,并分析了这些观点分歧的原因.在此基础上,进一步论证了我国农地产权制度的实践困境不在于“姓公”与“姓私”,而在于农地管理主体(政府)、开发主体(商人)以及经营主体(农民)各自权益边界不清,导致投机盛行,不利于社会公平与效率.为此要突破认识障碍,搁置农地公属私属之争,凝聚“确权”共识.即,以明确使用权而未必是所有权来充实土地权益内容;通过明确的权益边界,排除农地相关主体在使用和处置农地过程中的投机行为,维护公平与效率. 相似文献
64.
《Journal of Veterinary Behavior: Clinical Applications and Research》2014,9(4):143-150
The nature of the relationship between companion dogs and their owners has important impact on the effect of life for both dog and owner. Identifying factors that affect the dog–owner relationship will assist the understanding of how the successful relationship is achieved and how the less successful relationship is mended, with potential benefits for the welfare of both species. In the present study, we investigated the effect of several dog and owner characteristics, including the personality of the dog, on the dog–owner relationship as measured by the Monash Dog Owner Relationship Scale (MDORS). Data were collected by inviting owners of dogs that had been tested on the Danish Dog Mentality Assessment (DMA) to answer an online questionnaire. We were able to match 421 owner answers with their dogs' DMA test results. The questionnaire consisted of the 28 items of the MDORS, as well as questions about the owners and their dogs. Using factor analysis, 5 dog personality traits could be derived from the dogs' test results on the DMA. The predictive value of questionnaire-based owner and dog variables and the 5 dog personality traits on the dog–owner relationship was tested using multiple linear regressions: 1 for each of the 3 subscales of the MDORS. Overall, the variables investigated only predicted a small proportion of the variance in MDORS scores, and owner characteristics appeared to influence the dog–owner relationship more than dog personality traits did. We found that children in the family and using the dog only for company were negatively associated with the owners' perception of the relationship with their dogs. The only dog characteristics to predict the dog–owner relationship were fearfulness and fear-related behavior problems. 相似文献
65.
66.
提出了企业群为发挥核心企业的核心能力而以供应链和部分产权关系为纽带所组成的企业联盟这一半虚拟企业的概念,通过对半虚拟企业特点和供应链结构模型的分析,引入了一种半虚拟企业的物流模式,分析了该物流模式中相关企业间的物流关系及实际案例,指出该模式在核心企业具有较强的物流经营能力时,可以合理兼顾各成员企业的利益,有效降低物流成本,提高物流质量. 相似文献
67.
68.
林权证管理信息系统总体设计 总被引:1,自引:0,他引:1
分析目前我国林权证管理信息系统的现状和存在的问题,通过系统需求分析,提出基于MS SQLServer2005,Microsoft Visual Studio C#,ArcEngine开发设计的林权证管理信息系统;在此基础上设计林权证管理信息系统的开发构架、开发环境、运行环境、功能模块,以期提高工作效率和发证质量,为集体林权制度改革服务。 相似文献
69.
Harandi MF Moazezi SS Saba M Grimm F Kamyabi H Sheikhzadeh F Sharifi I Deplazes P 《Zoonoses and public health》2011,58(8):582-588
Cystic echinococcosis (CE) caused by larval stage of Echinococcus granulosus, is an endemic zoonosis in Iran particularly in rural regions. The objective of this study was to determine the prevalence of CE among rural communities in Kerman using ultrasonography (US) and serology. Kerman Province, in southeastern Iran, is the largest province, with 2.9 million inhabitants. A sample of 1140 individuals (200 males and 940 females) was selected by randomized cluster sampling in 2006-2008. After acquiring informed consent for each participant a questionnaire was filled, complete abdominal US in supine position was carried out and 5 ml blood was collected for ELISA test. Two hydatid cases (0.2%) were detected by ultrasound. Serological results showed 7.3% seropositivity, and females (8.3%) were significantly more positive than males (2.1%). There were significant difference between CE seropositivity and sex, age and occupation. Residents of desert regions (Shahdad, Andouhjerd and Golbaf) were 2.5 times more likely to be seropositive than mountainous regions with better socioeconomic status (OR = 2.5; 95% CI = 1.09-5.95). Dog ownership does not appear to be a significant risk factor for CE in the region. Only about 10% of households own dogs, usually only one dog. However, the stray dog population of Kerman province is estimated at 145 000-480 000 (3.5-11.5 times the owned dog population). Infection in humans and animals would appear to come mostly from infected stray dogs. Management of stray dog population could make major progress in control of hydatid disease. In addition, proper washing of vegetables decreased probability of infection by 53% (OR = 0.47; 95% CI = 0.26-0.84). The serological study showed that many people, especially women, had been exposed to Echinococcus eggs and had seroconverted but were not infected. 相似文献
70.
A spreadsheet population dynamics model was constructed to evaluate the impact of female dog sterilization on the domestic dog population for the province of Teramo, Italy. Baseline owned dog population structure as well as the annual number of births, adoptions, abandonments, and purchases were estimated based on regional managed kennel data in addition to a telephone questionnaire administered to members of the local population. Age- and gender-dependent death rates were based on domestic dog life tables. The model predicts that at the current female dog sterilization rate of 30%, the owned dog population will most probably continue to increase. After 20 years, a mean annual increase of 2.6% (median: 2.5%, 95% CI: −3.2% to 8.8%) is projected assuming that the average age at sterilization is 3 years. A sterilization rate of at least 55% is estimated to be needed to halt population growth if the current age structure for female dog sterilization is maintained. However, if the province of Teramo were to focus on sterilizing female dogs less than 1 year of age, the required sterilization rate to arrest population growth could be reduced to as low as 26%. 相似文献