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Comparison of impacts of economic and social factors on countries' logistics performances: a study with 26 oecd countries

Guner S., Coskun E.

Research in Logistics & Production

2012

Vol. 2, No. 4

330-343

The aim of this study is to set forth the relationship of economic and social factors with logistics performance of countries', which is very important for their competitiveness. To achieve this, researchers had correlated the logistics performances of twenty six OECD countries with a variety of economic and social indicators and interpreted the results. Analysis of results shows that, contrary to expectations, social indicators are more related with logistics performance than economic ones. The article discussed findings and reasons for them.

Key factors in the site selection of Rosa canina (L.) - applying the Generalized Additive Model

Guner S., Ozkan K., Comez A.

Polish Journal of Ecology

2011

Vol. 59, nr 3

475-482

Determining suitable sites for species is of great importance in the choice of plant species to be used for ecosystem restoration. The number of plant species to be used in restoration of degraded ecosystems is restricted by climate in arid and semi arid regions. Planting with economically important species in addition to ecological aspects is preferred by decision makers in Mediterrenian countries including Turkey. This study was addressed to determine the significant environmental factors influencing the distribution of dog rose hip (Rosa canina) and to obtain its distribution model. The study was carried out in an area of 26,400 km2 in The Inner Anatolia which has semiarid climate. 106 sample plots, 20 x 20 m in size, were selected from different sites with and without Rosa canina in the summer of 2007. Wilcoxon rank-sum statistic for continuous variables and Pearson Chi-square tests for categorical variables were applied. Altitude, slope degree, available water capacity, soil reaction and soil K, Ca, Mg content as well and total calcium carbonate amount as the continuous variables and northwest-northeast group of aspect, metamorphic group of bedrock as the categorical variables were determined as the significant factors influencing the presence of dog rose. Generalized Additive Model (GAM) was performed for modeling the distribution of the species. To obtain the best model, all significant environmental factors were evaluated. The best model result was obtained (training Area Under Curve (AUC) = 0.902 and cross-validation AUC = 0.841) by means of altitude, slope degree, aspect, and bedrock. Interspecific correlation analysis (ICA) was applied to define indicator species accompanying the dog rose. Dog rose distribution was positively correlated with Cistus laurifolius, Pyrus elaeagnifolia, Lonicera caucasica subsp. orientalis, Quercus vulcanica and Amelanchier rotundifolia subsp. rotundifolia. The results obtained from this study are crucial for estimation of the suitable areas for Dog rose in restoration studies of natural ecosystems in the Mediterranean region, including Anatolia in Turkey.