林业经济学领域的拓展

当前的林业经济学模型,构建于木材永续利用体系和新古典经济学框架之上,存在着诸多局限性。森林可持续经营(sustainableforestmanagement,SFM)体系中的社会、经济和生态因素不同于木材永续利用。因此,SFM经济学将以多元均衡经济学和消费者偏好理论为基础。其中,消费者偏好理论考虑了个体的复杂性、环境的特殊性、偏好的动态性、需求的差异性以及需求的层次性等因素。鉴于SFM的内在要求,有必要拓展林业经济学领域。发展经济学、制度经济学、生态经济学以及经济学的其他新流派理论为该学科领域的拓展提供强有力的支持。     

ASSESSMENT OF ANIMAL SKIDDING AND GROUND MACHINE SKIDDING UNDER MOUNTAIN CONDITIONS

INTRoDUCTlONHcilongiiangProvillce'with46o,()o()squarekilometcrsarcaand35l11llllOI1popula-tion'islocatedinnortI1castpaftofChlnaFor-cstland'\\llicl1isma1l1l\don1il1atcdbxtl1rcclargcIbrcstareasfylchunForestAIca(YC)-MudanjlangForestArea(MDJ)andDaxi-llanIingForcstArca(DXL).co\'ersncarI}36'\,ot'totalIal1darca,Morcthanthirt3pcr-cClltoftotaItil11bcruscdinCl1inasinccI94()Ilascol11cfrol11HeilonVia11gPro\'i11cc.Forcsthari'estingil1HcilonVial1gForestRcgionhasbcenchangcdgrcatI}'.Assl1ox…     

Gamma generalized linear model to investigate the effects of climate variables on the area burned by forest fire in northeast China

The purpose of this study was to determine a suitable model for investigating the effects of climate factors on the area burned by forest fire in the Tahe forest region, Daxing’an Mountains, in northea...     

Effects of fucoidan on angiogenesis of human multiple myeloma RPMI 8226 cells

AIM: To investigate the effects of fucoidan on the angiogenesis of multiple myeloma cells in vitro, and its related mechanisms. METHODS: The human multiple myeloma RPMI 8226 cells and human endothelial cells were cultured in vitro. The growth inhibition rate of RPMI 8226 cells was examined by MTT assay. The cell cycle and apoptosis rate were measured by flow cytometry. RPMI 8226 cells were treated with fucoidan for 72 h, and the cell culture supernatant was collected. The VEGF concentration was examined by ELISA, and the tube formation assay was applied to assess the angiogenic activity. After treatment with fucoidan for 72 h at different concentrations, the protein levels of HIF-1α, VEGF, p-AKT and p-ERK1/2 were detected by Western blot. RESULTS: Fucoidan inhibited the growth of RPMI 8226 cells in a dose- and time-dependent manner. After treatment with fucoidan for 72 h, the cell cycle was arrested at G₁ phase, and the apoptotic rate of RPMI 8226 cells was increased with the increasing concentration of fucoidan, which was much higher than that in control group (P<0.05). The VEGF concentration was significantly decreased with the increa-sing concentration of fucoidan. The numbers and areas of the capillary-like structures decreased while the concentration of fucoidan increased, and those at 100 mg/L were less than those in the control (P<0.05). The protein levels of HIF-1α, VEGF, p-AKT and p-ERK1/2 in fucoidan group were significantly lower than those in control group (P<0.05). CONCLUSION: Fucoidan inhibits the secretion of VEGF in multiple myeloma cells, and reduces angiogenesis induced by multiple myeloma cells. It inhibits the protein expression of HIF-1α and VEGF, which may be related to inhibiting the phosphorylation of AKT and ERK1/2.     

北京果园土壤养分和pH与微生物数量的相关分析及优化方案

通过对北京苹果、梨、桃和葡萄48个果园0～40 cm土层土壤养分、pH和微生物种群数量的调查,应用典型相关、多元统计分析与线性规划等方法分析土壤养分、pH对土壤微生物种群数量影响的主要因子、相关性和优化方案。结果表明,土壤有机质、全氮、有效钾、有效铁和阳离子交换量(cation exchange capacity,CEC)以及土壤中的细菌、真菌数量以苹果园最高,葡萄和桃园次之,梨园最低。土壤细菌数量与土壤有机质、有效磷和有效硼含量呈显著正相关,与土壤全氮含量呈显著负相关;真菌数量与土壤全氮、有效钾和CEC呈显著正相关;放线菌数量与土壤有机质、有效锌和有效硼含量呈显著正相关,与有效磷含量呈显著负相关;土壤pH与细菌和真菌数量均呈显著负相关。线性规划求出了8—10月土壤微生物种群数量最大的土壤养分和pH因子优化方案为:土壤有机质为55.0 g.kg-1、全氮为1.50～3.00 g.kg-1、有效磷为20～200 mg.kg-1、有效钾为120～600 mg.kg-1、有效锌为0.5～20.0 mg.kg-1、有效硼为10 mg.kg-1、CEC为300 mmol.kg-1、pH值为6.5。北京地区果园通过提高土壤有机质含量和CEC、降低果园土壤pH值来调节锌、硼等微量元素含量是土壤管理中的关键技术措施。     

基于遗传算法的苹果产量组合预测模型研究

苹果产量的预测不仅能为社会和经济管理决策提供可靠的依据,也给有关部门编制计划提供重要的数据.首先介绍了指数曲线模型、多元线性回归模型和组合预测模型.通过比较发现,组合预测模型能充分利用单个预测模型的优点,能够有效地减少单个预测模型受随机因素的影响,从而提高预测的精度和稳定性.为此,提出了苹果产量组合预测模型,将指数曲线...     

土耳其伊兹密尔轻轨车辆乘客信息系统集成设计

对土耳其伊兹密尔轻轨车辆乘客信息系统的系统集成、接口功能实现等方面进行了详细描述。     

冬麦后复种糯玉米品种试验

对7个鲜食糯玉米品种开展麦后复种育苗移栽试验,分别从生育进程、果穗性状、综合品质和产量效益等方面进行了分析,结果表明:品种甜糯8010适合灵武市冬麦后种植。     

宁夏引黄灌区春小麦复种蔬菜适宜种类筛选

复种是提高土地利用率及保证区域粮食安全的重要措施之一,宁夏引黄灌区近年来农业区域气候资源变化趋向利于多熟制,研究筛选春小麦复种蔬菜的适宜种类成为区域农作制度发展的必然。本试验选择灌区具有生产潜力的17种蔬菜与春小麦复种,运用层次分析方法(AHP),设3个2级指标, 12个3级指标,通过对各模式相应评价指标测定及分析,筛选适于灌区的麦后复种蔬菜的两熟制模式。结果表明:近10年来,灌区年≥10℃积温3407.9℃,降水量206.4 mm,无霜期208.4 d,蒸发量1619.3 mm。主要气候因子理论上可以满足麦后复种叶菜类和根菜类蔬菜,但与理论生产潜力相比较,实际产量的提升空间较大;麦后复种果菜类的气候资源不足。17种蔬菜中,春小麦复种的白萝卜、满堂红萝卜、娃娃菜、黄瓜(‘626’) 4种蔬菜资源利用效率较高;春小麦复种的胡萝卜、白萝卜、芹菜、西红柿(‘丰收128’) 4种蔬菜提升地力效果较好;春小麦复种娃娃菜、白萝卜、满堂红萝卜、小辣椒(‘娇龙7号’) 4种蔬菜经济效益较高。综合评价,得出适宜宁夏引黄灌区春小麦后复种的8种蔬菜为:娃娃菜、白萝卜、满堂红萝卜、辣椒(‘娇龙7号’)、辣椒(‘洋大帅’)、苦苣、芹菜和西葫芦,分别比综合效益最低的小麦-苤蓝种植模式高143.0%、121.5%、77.7%、46.3%、43.0%、35.5%、33.1%和33.0%,可大面积推广。