人口密度分布对地价影响的实证研究

将人口密度分布应用于地价分析是对改进传统地价模型的一种尝试。每一块土地都具有面积、形状、位置、周边环境等一系列土地特性,因而形成相应的地价。作者在本文中把土地特性分为区属特性和地点特性,将人口密度作为体现该地区社会经济活动的区属特性导入模型,使人口密度分布和地价的关系趋于明朗,进一步区分了常住人口密度和从业人员密度对地价的不同影响,建立了旨在同时说明住宅地和非住宅地地价的模型,并以日本地方省会城市冈山市为例进行了实证分析。

Allometric prediction of above-ground biomass of eleven woody tree species in the Sudanian savanna-woodland of West Africa

Allometric models are necessary for estimating biomass in terrestrial ecosystems. Generalized allometric relationship exists for many tropical trees, but species- and region-specific models are often lacking. We developed species-specific allometric models to predict aboveground biomass for 11 native tree species of the Sudanian savanna- woodlands. Diameters at the base and at breast height, with species means ranging respectively from 11 to 28 cm and 9 to 19 cm, and the height of the trees were used as predictor variables. Sampled trees spanned a wide range of sizes including the largest sizes these species can reach. As a response variable, the biomass of the trees was obtained through destructive sampling of 4 754 trees during wood harvesting. We used a stepwise multiple regression analysis with backward elimination procedure to develop models separately predicting, total biomass of the trees, stem biomass, and biomass of branches and twigs. All species- specific regression models relating biomass with measured tree dimen- sions were highly significant （p 〈 0.001）. The biomass of branches and twigs was less predictable compared to stem biomass and total biomass, although their models required fewer predictors and predictor interac- tions. The best-fit equations for total above-ground biomass and stem biomass bad R2 〉 0.70, except for the Acacia species; for branches including twig biomass, R2-values varied from 0.749 for Anogeissus leiocarpa to 0.183 for Acacia macrostachya. The use of these equations in estimating available biomass will avoid destructive sampling, and aid in planning for sustainable use of these species.

Effect of Milk Proteins on Physical and Chemical Characteristics of Crispy Puff Snacks

Dairy proteins included sweet whey solids （SWS）, whey protein concentrate （WPC）, milk protein concentrate （MPC） or sodium caseinate （SC） at level of 10% by weight were extruded with corn, rice, oat flour and other ingredients in a twin screw extruder. The functional properties and textural of crispy balls snacks （CBS） have been studied. The results showed that different protein types were significantly affected on functional and chemical properties of extrudate. The bulk density of CBS-SC was the lowest due to the highest expansion, while CBS-WPC retained the most water in the product, whereas, the maximum value of water solubility index was obtained in the CBS-CWP. Results also showed that protein digestibility value of extrudates had higher than non-extruded products. Color analysis of CBS-SC and CBS-SWS products had the highest AE values （P ≤ 0.05）, whereas CBS-SWS was statistically higher than CBS-SC in rank. Also, it was noticed that CBS-SWS had the highest value of browning index. The hardness of all extrudates products was desirable for expanded crispy where ranged from 17.3 N to 12.18 N. Generally, MPC and SC incorporated with cereal flour had acceptable quality characteristics and improved significantly the functional and texture properties of crispy balls products.

Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas as derived from TRMM PR

Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas are investigated based on the measurements of Tropical Rainfall Measuring Mission's(TRMM) Precipitation Radar(PR) from 1998 to 2007.Results indicate that convective precipitation are distributed mainly over the Intertropical Convergence Zone(ITCZ),the South Pacific Convergence Zone(SPCZ),the Asian Monsoon Region,regions between the South America and the Mid-America,and the Tropical Africa where the frequencies lie between 1% and 2%.But in four seasons,total area fractions of convective precipitation frequencies less than 1% all exceed 85%.The frequencies of stratiform precipitation are much higher than those of convective precipitation,and total area fractions of stratiform precipitation frequencies >1% are over 55% during four seasons.However,frequencies of the two rain types show not only remarkable regionality,but also distinct seasonal variations.Conditional rain rates of convective precipitation range from 6 to 14 mm/h whereas those of stratiform precipitation are smaller than 4 mm/h.Meanwhile,rain tops of convective precipitation are higher than those of stratiform precipitation.The mean profiles of the two rain types show significant latitudinal dependency.And the seasonal variations of precipitation profiles are displayed mainly in the variations of rain tops.The frequencies and conditional rain rates of both rain types over ocean are higher than those over land,but rain tops are just the opposite.Moreover,the seasonal variations of both rain types over ocean are weaker than those over land because of the different stable states of underlying surfaces.