Optimization of causative factors using logistic regression and artificial neural network models for landslide susceptibility assessment in Ujung Loe Watershed, South Sulawesi Indonesia

Landslide susceptibility maps(LSMs) play a vital role in assisting land use planning and risk mitigation. This study aims to optimize causative factors using logistic regression(LR) and an artificial neural network(ANN) to produce a LSM. The LSM is produced with 11 causative factors and then optimized using forward-stepwise LR(FSLR), ANN, and their combination(FSLR-ANN) until eight causative factors were found for each method. The ANN method produced superior validation results compared with LR. The ROC values for the training data set ranges between 0.8 and 0.9. On the other hand, validation with the percentage of landslide fall into LSM class high and very high, ANN method was higher(92.59%) than LR(82.12%). FSLR-ANN with nine causative factors gave the best validation results with respect to area under curve(AUC) values, and validation with the percentage of landslide fall into LSM class high and very high. In conclusion, ANN was found to be better than LR when producing LSMs. The best Optimization was combination of FSLR-ANN with nine causative factors and AUC success rate 0.847, predictive rate 0.844 and validation with landslide fall into high and very high class with 91.30%. It is an encouraging preliminary model towards a systematic introduction of FSLR-ANN model for optimization causative factors in landslide susceptibility assessment in the mountainous area of Ujung Loe Watershed.

Eco-morphological characteristics of fern species for slope conservation

Degradation of slopes due to shallow landslide and the subsequent erosional processes are a big challenge on the application of soil bioengineering techniques; that is the use of plants as main structural components of a slope protection and conservation system. An optimal application of soil bioengineering techniques should include not only the technical factor of plants as structural components but also the ecology of species and the plant adaptations to disturbances, which is crucial if a longterm successful slope restoration system is intended. Ferns are a dominant understory vegetation species in the forest of Japan, but its characteristics and influences on the recovery of shallow landslide scars have not been fully studied yet. This study aims to find out the ecological characteristics of fern species through the calculation of ecological indicators and the quantification of the morphological features of specimens growing on disturbed and non-disturbed forest slopes in Japan. Gleichenia japonica was found as the vegetation species with biggest ecological indicators on both slopes. The analysis of morphological characteristics of the specimens growing on both sites showed that the development of the specimens is focused in below-ground characteristics. The pull-out force of Gleichenia japonica root system as an indicator of ecological adaptation to a constraint environment and morphological characteristics quality is influenced by height and root length according to the principal component analysis. The eco-morphological characteristics of species can be used as an indicator of an optimal element in soil bioengineering establishment for slope conservation proposes. The long and fibrous root system could be placed on forest roads, steep or small slopes where space limitation is an issue for the establishment of bigger species and if the slope conditions allow it, it can control soil losses due to rainfall and provide stability.

A Phase II Study of Erlotinib in Patients with Previously Treated Non-Small Cell Lung Cancer

Background: Erlotinib has been reported to be effective for the treatment of non-small cell lung cancer (NSCLC). To evaluate the efficacy and safety of erlotinib under conditions similar to daily clinical practice, a phase II trial was conducted in Japanese patients with previously treated NSCLC. Methods: The eligibility criteria were stage IIIB/IV NSCLC, a performance status (PS) of 0 - 2, and previous treatment with 1 - 2 non-EGFR-TKI regimens. Patients received erlotinib (150 mg/day) orally until disease progression or intolerable toxicity occurred. The primary endpoint was the objective response rate (ORR). In addition, the disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and EGFR gene mutation status were evaluated. Results: Thirty-eight patients were enrolled, and 37 patients were evaluated. The median age was 69 years (range, 50 - 80 years). Patient characteristics were as follows: 26 were male and 11 were female;12 had a PS of 0, 20 had a PS of 1, and 5 had a PS of 2;and 26 had adenocarcinoma, and 11 had non-adenocarcinoma histology. The ORR and DCR were 21.6% (95% confidence interval [CI], 11.4% - 37.2%) and 54.1% (95% CI, 35.9% - 66.6%), respectively. Twenty-seven patients could be evaluated for EGFR gene status (12, mutated;15, wild-type). The ORR for EGFR-mutated patients was 41.7%, while that for patients with wild-type EGFR was 13.3%. The median PFS was evaluated as 4.4 months (95% CI, 2.2 - 10.7 months). The median OS was 14.9 months (95% CI, 9.2 months - not reached). Common adverse events were tolerable skin toxicities, diarrhea, and stomatitis. In addition, interstitial lung disease occurred in 8.1% of patients. Conclusion: As efficacy and safety were similar to previous studies, erlotinib was found to be effective for Japanese patients with previously treated NSCLC in clinical practice.