Forests have been constantly growing with their dynamic structure. In order for this dynamic structure must be managed based on sustainable perspective. Diameter, height, age, stand structure, etc. parameters are used in the inventory stage of the planning. The easiest to measure among these parameters is the diameter. Therefore, the developed models are usually aimed at reaching other forest parameters from the diameter. In this article, 9 different height-diameter models were fitted using regression models, and feed-forward backpropagation artificial neural network model methods for uneven-aged fir (Abies nordmanniana subsp. equi-trojani) stands in Kökez, Bolu region of Turkey. The models compared based on adjusted R², bias, absolute bias, and root mean square error (RMSE). It was observed that the best result was obtained from the artificial neural network model, and the worst result was obtained from the power model.

This study deals with the effect of GeoGebra, one of the dynamic mathematics software, on high school students in learning the subject of geometrical place and the relationship of this effect with the socio-demographic characteristics of the students. The study was carried out with 12th grade students at a private high school located in Çankaya, Ankara. The assignments of the students included in the research to the experimental and control groups were made randomly, and the subject of geometric place was taught to the control group using traditional methods and to the experimental group using GeoGebra software. There were a total of 31 students, 12 girls and 19 boys, in the experimental group, and a total of 32 students, 14 girls and 18 boys, in the control group. "Personal Information Form" and "Achievement Test" prepared by the researcher were used in the research. In the Achievement Test applied as a pre-test, no statistically significant difference was found between the success means of the experimental group and the control group. In the Achievement Test applied as a post-test, a statistically significant difference was found between the experimental group and control group means in favor of the experimental group. On the other hand, a significant difference was observed between the pre-test and post-test in both the experimental group and the control group. In the analysis of the sub-problem of the research, there was a significant difference in the success mean of the experimental group according to the gender variable, but no significant difference was observed in the mean of success in the control group.

In the present study, the length-weight relationship of black sea trout (Salmo labrax) captured from the tributaries of the Ilgaz Stream was investigated. A total number of 36 individuals were captured during 2014-2015 and transported to the laboratory. Here, the length and weight values of the fish were measured and the age determination was performed. Afterward, the condition factor and length-weight relationship parameters were calculated. The age of the fish ranged between 1+ and 4+. The mean condition factor was found to be 1.30 ± 0.13 for all fishes. The total length of the fish ranged between 12.80 and 23.90 cm whereas the weight ranged between 20.52 and 203.46 g. The “b” value was calculated as 3.4 and the growth of the fish was determined to be isometric. It was inferred that the Ilgaz stream is rich in food and the black sea trout inhabiting the stream is well-nourished. The stream is a convenient source in terms of nutrition and future studies should explore other aspects of aquaculture to benefit from the source to grow fish.

In the study, the effect of some demographic characteristics of the employees of an enterprise operating in forest products on the levels of organizational identification was examined. The research population consists of the employees in the production facility of the company operating in the forest products industry sector. Within the scope of the study, 97 surveys were evaluated. As a result, it was determined that the organizational identification scale averages of the employees were at a moderate level. According to the logistic regression analysis, while there was a significant difference between the organizational identification levels of the employees according to the working time, there was no significant difference between the organizational identification levels according to the other demographic characteristics.

The regression analysis determines the relationship model between dependent and independent variables. In this study, the body weight, milking time, milk yield and environmental factors obtained from 42 dairy cattle were used for internal and external temperatures. In this study, the Bayesian Regression method was used to estimate milk yield parameters in case of multicollinearity. According to the results, it was seen that Bayesian method can be applied successfully in the field of animal husbandry. It is thought that the use of this study for dairy cattle in other agricultural areas will be useful for better evaluation of the data obtained.

In teleosts, biometric parameters of certain bony structures are used for the age and/or size determination of the fish. Otolith is perhaps the most widely used of these bony structures. There are numerous studies which have shown that otolith biometry is positively and strongly correlated with fish size. In this paper, some recent studies that investigate the relationship between otolith biometry and fish length are summarized. It is possible to estimate fish size and/or age by knowing this relationship. This information can be useful, especially when it is not possible to sample a certain portion of a fish population. Besides, otoliths found in archaeological excavation sites or in the stomachs of predators can provide information about the fish they belong to. These data are useful to taxonomists, paleobiologists, and researchers studying the nutritional biology of predators.