用层次分析法评测大学生就业竞争力

通过对大学生及用人单位进行就业问卷调查,分析了影响大学生就业竞争力的一些主要因素,建立了大学生就业竞争力层次模型。并利用层次分析方法评估大学毕业生的就业竞争力,从而指导大学生就业。     

Turbidity, velocity and interspecific interactions affect foraging behaviour of rosyside dace (Clinostomus funduloides) and yellowfin shiners (Notropis lutippinis)

Abstract –  Fish diversity is strongly affected by habitat degradation (e.g., increased turbidity) and invasive species. We examined the effects of turbidity, velocity, length, dominance and intra- and interspecific competition on focal point depth, movement rate, dominance and aggression rate in native rosyside dace ( Clinostomus funduloides ) and invasive yellowfin shiners ( Notropis lutipinnis ) in a southern Appalachian stream (NC, USA). We compared results for intra- and interspecific groups of fishes at two densities (two and four fishes), three turbidity levels (10, 20 and 30 nephelometric turbidity units), and two velocities (12, 18 cm·s⁻¹). Dominance was significantly correlated with length in intraspecific groups of both species, and dominant fish held more profitable foraging positions about 75% of the time. Yellowfin shiners were dominant more often than rosyside dace in interspecific trials. Akaike's Information Criterion indicated that models containing turbidity, velocity, species and intraspecific competition, explained the greatest amount of information in focal point depth data. By contrast, movement and aggression rates were best explained by models based on dominance and velocity. Finally, aggression rate was best explained by models containing fish length and turbidity. These results indicate that habitat degradation, intra- and interspecific interactions influence the foraging behaviour and future success of these species in the Little Tennessee River drainage.     

山东省中心城市竞争力定量分析

本文借鉴已有的关于城市竞争力分析的成果,建立了山东省中心城市竞争力的评价体系。采用因子分析方法对山东省17个中心城市(地级以上城市)2005年的城市竞争力作了综合评价,并给出最终的排名。     

试论建筑市场的价格竞争

论述了我国现阶段建筑市场价格竞争的现状，并对如何赢得价格竞争的途径进行了分析。     

Effects of Different Tree Species on Growth and Yield of Mung Bean (Vigna radiata (L.) Wilczek) Grown in Hedgerow Intercropping Systems in Sri Lanka

Reduction of crop yields due to resource competition from tree hedges is a serious drawback of hedgerow intercropping. This work quantified the competition of six potential hedgerow tree species ( Calliandra calothyrus , Desmodium ransonii , Flemingia congesta , Gliricidia sepium , Cassia spectabilis and Tithonia diversifolia ) on mung bean ( Vigna radiata ) grown as hedgerow intercrops at Pallekelle in the mid-elevational (367 m above sea level), subhumid (rainfall of 1400 mm year⁻¹) zone of Sri Lanka. Leaf area, total biomass and yield of mung bean in hedgerow intercrops showed a clear reduction closer to the hedgerows, whereas no such reduction was observed in a sole crop of mung bean. At 30 cm from the hedgerow, growth and yield of mung bean were significantly lower than in the sole crop, indicating significant competition from hedgerows. However, growth and yield of mung bean increased with increasing distance from hedgerows so that, at 150 cm, mung bean under Gliricidia and Desmodium showed significantly greater growth and yields than the control. In contrast, even the maximum mung bean yields under the rest of the species did not reach that of the control. The differences in competition with different hedgerow species are discussed in terms of variations between tree species in biomass production, quality of prunings and the possibility of root competition.     

Crop canopy development and structure influence weed suppression

Weed suppression characteristics of different winter cereal species and cultivars were studied in two field experiments in two successive years. Two cultivars each of barley, oats and wheat were studied using the weed Galium aparine L. at a range of densities. Significant differences were found in the suppressive abilities of the crop species: oats being the most suppressive, followed by barley and then wheat. Percentage yield loss was related to G. aparine density using a rectangular hyperbolic model. In 1995–96, significant differences between the two wheat cultivars were found, with cv. Avalon being able to suppress G. aparine growth much more effectively than cv. Spark. However, in 1996–97, high rainfall in May, June and July enabled G. aparine to escape suppression by the cultivars. Cultivar competitive ability was associated with high overall leaf area, resistance to loss of tillers under competitive pressure, greater height, canopy structure and development. The oat cultivars were more competitive at early growth stages than could be accounted for by their canopy structure; the possible contribution of allelopathic exudates to their suppressive ability is discussed.     

Competition between Artemisia frigida and Cleistogenes squarrosa under different clipping intensities in replacement series mixtures at different nitrogen levels

The relative competitive ability of Artemisia frigida Willd. (C₃, semi‐shrub) and Cleistogenes squarrosa (Trin.) Keng (C₄, perennial bunchgrass), grown in a greenhouse, was studied under three nitrogen fertilizer levels, three defoliation intensities and five competitive replacement series in a factorial arrangement. Relative yield total and the respective crowding coefficients for each species were calculated with reference to aboveground, below‐ground and total biomass. The index of aggressivity was also determined relative to total biomass. Cleistogenes squarrosa was a consistently weak competitor at all nitrogen fertilizer and clipping levels compared with A. frigida. Artemesia frigida had a higher relative yield when grown in mixtures with C. squarrosa than in monocultures, whereas the yield of C. squarrosa was lower in mixtures with A. frigida than in monocultures. The relative competitive ability of A. frigida over C. squarrosa declined significantly at different clipping intensities with increasing nitrogen fertilizer. The interaction of nitrogen fertilizer with clipping was significant, although the clipping effect on aggressivity was not significant.     

产品市场竞争对资本结构的作用机理研究

企业融资结构与产品市场竞争策略是企业发展中最重要的两项决策,两者间具有密切的相关关系。本文从产品市场竞争对企业在资本市场上融资能力的影响、产品市场竞争对企业资本结构选择的影响以及产品市场竞争对企业不同债务融资渠道选择的影响三个方面分析了产品市场竞争对企业资本结构的作用机理。     

Combined effects of wheat competition and 2,4-D amine on phenoxy herbicide resistant Raphanus raphanistrum populations

Phenoxy herbicides are integral to the control of Raphanus raphanistrum populations in Australian crop production systems, but the development of phenoxy resistant R. raphanistrum populations poses a major threat to the sustainability of these systems. In dose–response pot studies, phenoxy herbicide resistant R. raphanistrum populations, WARR12 and WARR20, suffered large biomass reductions following treatment with recommended or higher application rates of phenoxy herbicides. This indicates the presence of a weak resistance mechanism where treated plants, although surviving, are affected by these herbicides. Subsequently, the competitive ability of 2,4-D amine treated or untreated WARR12 and WARR20 populations with wheat was assessed using a target-neighbourhood experiment. The combination of wheat competition and 2,4-D amine application resulted in control of the resistant WARR12 population, but not the WARR20 population. Wheat crop competition alone resulted in large (>40%) biomass reductions of WARR12 and WARR20 populations. However, the application of the recommended rate of 2,4-D amine caused a large (>75%) reduction in WARR12 biomass, but had a reduced effect on WARR20 biomass. These studies possibly explain the largely successful control of R. raphanistrum populations being achieved with phenoxy herbicides in cropping systems across the Western Australia wheatbelt. However, the results also indicated that the strategy of combining crop competition with phenoxy herbicides for the control of this weed is likely to be an effective option in the short-term only.