基于DEA模型的山东省农地利用经济效益分析

山东省农地面积较广,利用类型丰富,农地的合理利用对推进山东省农业经济发展及土地资源的可持续发展具有重要意义。文章阐述了山东省农地利用状况,从自然因素、土地投入、农业土地利用结构、农业从业人员素质、农产品市场意识及经营手段等方面探讨影响农地利用经济效益的因素,通过构建DEA模型,对农地利用经济效益进行应用分析,并提出加大农业用地投入和建设、优化农业用地结构和规模、强化市场经营意识和管理等提高山东省农地利用经济效益的对策建议,以期为山东省土地合理规划利用提供理论依据。     

高密度开发城市土地利用对交通系统的影响作用研究--以广州为例

Recently the study on the mutual relationship between urban transport and land use has been one of the hot subjects in the fields of urban geography, urban transport planning and urban planning. This paper tires to carry out some methods, such as multi-analysis statistics method to specify the impacts of urban land use on urban transport system. Firstly,the choice of urban transport road network affected by the characters of urban land use layout is discussed. Secondly, the promotion of urban public transportation affected by high-density concentrated land use pattern is demonstrated Thirdly, the impacts of urban city-size on transport system structure characters are expatiated. Finally, the impacts of urban master planning in Guangzhou on the layout of transport system are illustrated.     

Post OPA-90 Vessel Oil Transfer Spill Prevention: The Effectiveness of Coast Guard Enforcement

Although oil spills from tanker accidents receive the most publicity, most vessel spills are not the result of accidents but of oil transfer activities. We investigate determinants of the size of vessel oil transfer spills as well as the effectiveness of Coast Guard enforcement activities in reducing their size. Vessel out-of-water and in-water oil transfer spillage functions are estimated utilizing tobit regression and detailed data on individual vessel oil transfer spills as well as Coast Guard safety/environmental enforcement activity data for the 1991–1995 period. Our estimation results suggest that Coast Guard hull but not machinery inspections are effective in reducing both out-of-water and in-water spills; patrols by air, but not by boat, are effective in reducing out-of-water spills; but neither is effective in reducing in-water spills. The results also show that the type of vessel (oil- and non-oil-cargo), vessel characteristics, vessel operations, weather/visibility conditions, and waterway type are determinants of post OPA-90 vessel oil transfer spills.     

排污权有偿使用阶梯式定价研究——以化学需氧量排放为例

依据河南省2010年污染源普查数据,分析了不同行业化学需氧量排放的公平性问题,基于不同行业经济贡献与排污量之间的差异性的基础上,参考阶梯水价和电价的制定思路,提出了排污权阶梯式定价,并对其内涵与经济学特征进行了分析,最后,在恢复成本法定价的基础上制定了河南省化学需氧量有偿使用阶梯式价格。     

基于成本补偿的水权定价模型研究

为缓解水资源短缺危机,我国开始尝试水权交易,但在交易中存在价格扭曲的现象,挫伤农民节水积极性。因此,解决水权交易中的价格问题意义重大。结合我国水权和水权交易性质,提出水权定价的原则,分析水权交易涉及的各种成本,主要包括工程成本、风险补偿成本、生态补偿成本和经济补偿成本。在此基础上,采用完全成本法进行水权定价,并且区分水权交易期限不大于节(输)水工程的使用寿命与交易期限大于节(输)水工程的使用寿命两种情况讨论,给出水权定价模型。为水权交易中的价格制定提供理论基础和方法,有利于水权市场的完善和水资源的高效利用。     

Cost-effectiveness analysis of sequential biologic therapy with ixekizumab versus secukinumab as first-line treatment of moderate-to-severe psoriasis in the UK

Aims: Patients with psoriasis often undergo treatment with a sequence of biologic agents because of poor/loss of response to initial therapy. With the availability of newer agents like ixekizumab and secukinumab, there is a need for cost-effectiveness analyses to better reflect current clinical practice. This study aimed to assess the cost-effectiveness of a sequence of biologic therapies containing first-line ixekizumab vs first-line secukinumab in patients with moderate-to-severe plaque psoriasis in the UK.

Materials and methods: A Markov model with a lifetime horizon was developed to compare the cost-effectiveness of ixekizumab and secukinumab treatment sequences: ixekizumab → ustekinumab → infliximab → best supportive care (BSC) vs secukinumab → ustekinumab → infliximab → BSC. The model used monthly cycles, and included four health states: trial period, treatment maintenance, BSC, and death. At the end of the trial period, responders transitioned to maintenance therapy; non-responders transitioned to the next biologic in the sequence. An annual discontinuation rate of 20% was assumed for maintenance therapy.

Results: The ixekizumab sequence provided cost savings of £898 (£176,203 vs 177,101) [year 2015 values] and gained 0.03 more quality-adjusted life-years (QALYs: 1.45 vs 1.42) vs the secukinumab sequence over the lifetime horizon. Probabilistic sensitivity analysis showed an 89.8% likelihood that the ixekizumab sequence would be cost-effective at a threshold of £20,000 per QALY gained.

Limitations: The analysis used list prices for drugs rather than confidential, preferentially priced Patient Access Scheme costs. In addition, efficacy input data were based on a network meta-analysis, as there were no head-to-head trials comparing ixekizumab and secukinumab.

Conclusion: First-line treatment with ixekizumab as part of a specific sequential biologic therapy for moderate-to-severe plaque psoriasis in the UK provided slight advantages in cost savings and QALYs gained over a similar treatment sequence initiated with secukinumab. In view of the small magnitude of these differences, factors such as patient preferences (e.g. for number of injections) and long-term safety (e.g. related to time on the market) may also be important for clinical decision-making.     

互联网应用与创业绩效:社会资本的中介作用

借助社会资本理论,探究了与企业经营密切相关的互联网应用——信息获取与社交沟通如何通过社会资本积累对创业绩效产生影响。利用来自中国2432家创业企业的调研数据进行实证研究。结果显示:社会资本中的服务者联系对互联网应用的信息获取维度与创业绩效的关系起部分中介作用;社会资本中的参与者联系对互联网应用的社交沟通维度与创业绩效的关系起部分中介作用。     

新疆水资源承载力探析

新疆水资源制约着新疆的绿洲经济发展,分析水土资源之间的关系有助于合理配置水资源。本文通过水土资源之间的关系分析,估算了新疆水资源的承载能力,从而得出新疆水资源量是稳定且有潜力的,并且能够支撑新疆社会经济发展的结论。     

社会资本视角下农民用水户满意度研究——基于陕西省宝鸡峡灌区农民用水户的调查

以社会资本为研究视角,对社会资本维度进行划分,并运用有序Logistic模型,基于陕西省宝鸡峡灌区农民用水户的调查,研究农民用水户对农民用水户协会的满意度及影响因素。研究结果表明,结构维度和认知维度社会资本是影响用水户对协会满意度的重要因素,家庭收入水平、农业收入占家庭收入比重、渠系完好率、协会专业化程度以及用水户参与积极性对用水户满意度有显著影响;关系维度社会资本、用水户性别、年龄、文化程度对用水户满意度没有显著影响。这表明农民用水户协会主要承担着灌溉管理和农业发展的职能,而其承担的社会功能相对较弱。     

基于村级尺度的农村水贫困评价——以常德澧县梅家港村为例

以WPI为基本框架,结合南方农村社区水资源系统的特点,从水资源状况、供水设施、利用能力、使用效率和环境状况五方面选择24个指标,建立一套南方农村社区水贫困评价指标体系.采用分级打分法量化数据,构建综合指数评价模型,并对湖南澧县梅家港村水贫困水平进行评价.结果表明:梅家港村的WPI指数值为46.567,呈现一定程度的水贫困现象.其水贫困主要表现在水资源使用效率低下、环境状况堪忧以及供水等水利基础设施相对落后等方面.该项研究说明,我国南方自然水资源条件优越的农村地区同样有可能存在不同程度的水贫困问题.