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Comparison of Least Squares, Ridge Regression and Principal Component Approaches in the Presence of Multicollinearity in Regression Analysis
2019
Soner Çankaya | Samet Eker | Samet Hasan Abacı
The aim of this study was to compare estimation methods: least squares method (LS), ridge regression (RR), Principal component regression (PCR) to estimate the parameters of multiple regression model in situations when the underlying assumptions of least squares estimation are untenable because of multicollinearity. For this aim, the effect of some body measurements on body weights (height at withers and rumps, body length, chest width, chest girth and chest depth, front, middle and hind rump width) obtained from totally 85 Karayaka lambs at weaning period raised at Research Farm of Ondokuz Mayis University was examined. Mean square error, R2 value and significance of parameters were used to evaluate estimator performance. The multicollinearity, between front and middle rump width which were used to estimate live weight, was eliminated by using RR and PCR. Although research findings showed that RR method had the smallest MSE and the highest R2 value, the estimates of PCR were determined to be more consistent when the importance tests of parameters were taken into account. The results showed that principal component regression approach should be used to estimate the live weight of Karayaka lambs at weaning period.
Mostrar más [+] Menos [-]Validation of The Weather Generator CLIGEN with Season Precipitation Data in Tokat Province
2019
Saniye Demir | İrfan Oğuz
In models that predict hydrologic, ecological and product-yield relationship, the climate interface file is widely used. Today, CLIGEN is the most widely used climate model. While this model is extensively used in many countries around the world, it is not used commonly in our country. In this study, daily data belonging to Tokat climate conditions were simulated with CLIGEN. Observed and simulated precipitation was classified as the wet/dry period. The performance of the CLIGEN climate model was evaluated in both wet and dry periods according to the seasons. The relationship between the obtained precipitation data was statistically determined by Kolmogorov-Smirnov and t-test. Tokat province is located in the arid and semi-arid climate zone. The performance of the model in predicting precipitation in all seasons during the dry period was found to be quite successful.
Mostrar más [+] Menos [-]Investigation of Genetic Diversity in Afghan Bread Wheat Genotypes Using SSR and AFLP Markers
2019
Mohammad Bahman Sadeqi | Said Dadshani | Mohammad Yousefi | Gul Mohammad Ajir
Genetic diversity assessment is the principle component for conservation and characterization of germplasm. Genetic diversity study of Afghan bread wheat genotypes is a first step to identify and to select high performance genotypes and distribute to wheat breeding programs. The main objective of this study is to investigate of genetic diversity in 35 Afghan bread wheat genotypes by using Simple Sequence Repeat (SSR) and Amplified Fragment Length Polymorphism (AFLP) markers. DNA extraction according to Cetyl Trimethyl Ammonium Bromide (CTAB) method was conducted and the total genomic DNA was isolated from each variety. Sixty-four SSR primer markers were used and eighteen EcoRI+(N)/MseI+(N) primer combinations with their primer sequences were used for selective polymerase chain reaction (PCR) amplification. Every SSR and AFLP fragment was scored as present (1) or absent (0) within all genotypes under study. Marker/ Value ratio of pairwise genetic distance between genotypes according to the SSRs data was from 0.508 to 0.691 with an average distance of 0.599. Relatively different grouping pattern in comparison to AFLP data observed through cluster analysis. Both types of molecular markers (AFLP and SSR) used in this research proved to be suitable for investigating genetic diversity in the genotypes of Afghan bread wheat, however, AFLP markers gave better view of genetically relationships among genotypes than the SSR markers. The grouping generated by AFLP data showed a special agreement with the origin regions of genotypes (Ariana-07 and Mazar-99 originating from the north of Afghanistan, Lalmi-03 and Kabul-02. Large number of DNA bands identified with AFLP markers might provide a better estimation of genetic similarity than those of SSR markers.
Mostrar más [+] Menos [-]Properties of Solvent Cast Polycaprolactone Films Containing Pomegranate Seed Oil Stabilized with Nanocellulose
2019
Ece Söğüt
The increase of consumer demand for using natural products and reducing the use of non-compostable packaging materials have encouraged research on biodegradable polymers including natural components such as essential oils. Pomegranate seed oil (PSO) has active properties such as antimicrobial and antioxidant activities. The aim of this study was to prepare active polycaprolactone (PCL) films by using PSO. PCL films including PSO emulsions (5-30%), which were stabilized with nanocellulose (NC) particles, were prepared by casting method. The physical and active properties of PCL films were determined by means of water vapor permeability (WVP), mechanical properties, optical properties, release behaviour, and potential antimicrobial activity. The WVP values of PCL films was lower when incorporated with NC-stabilized PSO emulsions. The incorporation of PSO into PCL films in the form of NC-stabilized emulsions significantly reduced the transmittance and lightness values, which resulted in an increase in opacity. In the release tests, the slower release of PSO was observed for NC-stabilized films. The stabilization of PSO with NC showed to be less effective when high concentrations of oil (30%) were used. Film samples showed potential antimicrobial activity against Escherichia coli, and Listeria monocytogenes, however, a clear zone of inhibition around the film samples was not detected. Results also suggested that the antimicrobial effect was dependent on two important factors: the release behaviour of PSO through the film samples and, the direct interaction between PSO and microorganisms. These results showed that the combination PCL films and PSO stabilized with NC could be an interesting approach in active packaging technologies.
Mostrar más [+] Menos [-]The Systematic Composition of Bacillariophyta members from Ergene River (Thrace Region, Turkey)
2019
Rıza Akgül | Füsun Akgül | Veysel Aysel
There are a good many researches carried out to be able to find out the species of phytoplanktonic organisms which are widely met in the inland waters of Turkey and make up the first link of food chain in nature. In addition to this, there are lots of water sources the phytoplanktonic composition (one of the most effective methods of identifying drinking water in Turkey in which inland waters cover a huge area) and biodiversity of which have not been found out and listed. Ergene River is among the richest water basins in Turkey in terms of freshwater and there is not a comprehensive research carried out to determine the algae composition in this area. For that reason, Bacillariophyta members which are met in main streams supporting Ergene River, have been gathered seasonally; and systematic positions of these algae have been identified and photographed. As a consequence of this study; 114 different taxa species belonging to Coscinodiscophyceae (4) and Bacillariophyceae (110) taxa have been observed and found out in Ergene River and other watercourses along with water basins supporting this river. After these taxa have been gathered, how these are spread with regard to seasonal and sample points have been determined. All of these taxa, which have been identified with respect to freshwater algal flora of Turkey, have been recorded for the first time for that region while 22 of these taxa have been recorded for the first time for Turkey.
Mostrar más [+] Menos [-]The Importance of Gamma Aminobutyric Acid Produced by Lactic Acid Bacteria
2019
Seda Yalçınkaya | Gülden Başyiğit Kılıç | Aynur Gül Karahan Çakmakçı
Gamma aminobutyric acid (GABA) is known as an important inhibitory neurotransmitter in the human brain. Recent studies have proved the beneficial effects of GABA on human health. It has been reported that in people who use GABA supplements, the factors affecting the life quality negatively such as psychological problems, insomnia and immune problems have decreased. Studies in this field have shown that lactic acid bacteria (LAB) can produce GABA. For this reason, interest in LAB producing GABA is steadily increasing. It is stated that GABA produced by natural LAB has almost no side effects compared to synthetically created ones. It is also suggested that GABA-producing LAB, which is isolated from especially in Far East countries foods, should be used to develop functional foods. More research needs to be done in order to proceed in this newly developing area, and the undiscovered features of GABA need to be investigated. In this review, the importance of GABA is addressed and the studies about GABA are examined.
Mostrar más [+] Menos [-]The Effects of Various Improvement Methods Applications on Herbage Yield of Natural Pastures
2019
Ayşe Çalık | Tahir Polat
In this study, which was performed on an over-grazing pasture in Şanlıurfa under the influence of a dry climate, the effects of different breeding methods such as natural(control), fertilization, insemination, fertilization+insemination+insemination+insemination + release on natural pastures were investigated. In order to increase the yield potential of Natural Pastures in the research area, manure, seedling, fertilization+seedling, fertilization+seedling+version methods were applied on both protected and grazing fields. Using the transect method, key plant species in the region were determined. As a result of the research, according to two-year averages, the highest dry grass yield in grazing area was 47.98 kg/da fertilized seedlings and the lowest yield was 21.40 kg/da natural (control) seedlings. According to two-year averages, the highest dry grass yield in the protected area was obtained from 171.29 kg/da manure, and the lowest value was obtained from 82.77 kg/da natural (control) pasture. According to the results of breeding methods applied in the field of research; in addition to protecting pasture areas, a suitable fertilization is required. In addition, it was concluded that the desired result could be achieved by making a regular grazing according to the rules of grazing amanjman.
Mostrar más [+] Menos [-]Evaluation of Oat (Avena sativa L.) Genotypes for Yield and Some Quality Parameters in Trakya-Marmara Region
2019
Turhan Kahraman | Asiye Seis Subaşı | Özge Yıldız | Ceylan Büyükkileci | Turgay Sanal
This study was carried out in 2015-2016 cropping year in Kırklareli ve Edirne locations with 60 oat lines and 4 varieties of commercials (Kırklar, Kahraman, Yeniçeri and Sebat). The experiment was arranged in an alpha lattice experiment design (8 x 8= 64) with three replications. In the research, it was aimed to determine genotypes suitable for the region by examining yield and some quality parameter performances of oat genotypes.The traits such as grain yield (GY), thousand kernel weight (TKW), test weight (TW), plumpness (P, sieved 2.2 mm slotted), husk rate (HR), full grain oat protein (FGOP), starch (S), β-glucan (β-G) and L value (L) content of genotypes were investigated. The variation among oat lines for grain yield was significant and differences for TKW, TW, P, HR, FGOP, S, β-G, and LBV were also determined. The GY, TKW, TW, P, HR, FGOP, S, β-G and LBV of oat lines ranged between 588.3-860.8 (735.0) kg/da, 21.1-44.0 (31.9) g, 49.3-58.9 (54.7) kg/hl, 13.5-93.5 (69.9) %, 12.1-31.1 (23.9) %, 14.9-20.9 (18.1) %, 51.3-60.5 (56.2) %, 3.2-4.7 (4.0) % and 83.6-89.3 (87.1) in Kırklareli and 472.8-90.35 (681.3) kg/da, 23.0-41.3 (32.4) g, 42.9-55.3 (549.2) kg/hl, 22.4-95.8 (74.7) %, 18.3-30.8 (25.0) %, 14.9-20.3 (18.1) %, 53.1-62.8 (57.5) %, 2.9-5.0 (3.9) % and 84.2-89.9 (87.7) in Edirne respectively.The oat lines 14, 16, 19, 43, 3, 48 and Kırklar and Kahraman varieties were hopeful in Kırklareli and the oat lines 16,18,19, 21, 22, 44, 2, 51, 52 and Kahraman variety were hopeful in Edirne location for grain yield and investigated quality parameters. The oat lines 14, 16, 19, 21 and Kahraman variety were suitable in terms of investigated traits in Trakya-Marmara region.
Mostrar más [+] Menos [-]Evaluation of Gold Nanoparticles in Terms of Their Use in Biomedical Applications
2019
Burcu Biterge-Süt | Elif Canpolat
Recently nanotechnology has become an integral part of modern biomedical applications. Accordingly, nanoparticles are considered as promising components for the development of innovative tags, probes, biosensors and carrier molecules for drug delivery. Spherical colloidal gold nanoparticles (AuNPs) are prime candidates to be utilized for these purposes due to their useful physical properties. However, in order for the gold nanoparticles to be used in nanomedicine, their biological properties should be extensively studied as well. Therefore, in this paper we chemically synthesized gold nanoparticles and studied their physical and biological characteristics to determine their potential use in medicine. Gold nanoparticles were synthesized by the reduction of chloroauric acid (HAuCl4) solution with sodium citrate. The physical properties of the AuNPs were determined by UV–vis spectrophotometer and Zetasizer readings. The antimicrobial activity of the newly synthesized gold nanoparticles on Escherichia coli, Salmonella infantis, Salmonella kentucky, Salmonella typhimurium, Salmonella enteritidis, Pseudomonas aeruginosa, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Bacillus subtilis and Candida albicans were investigated via disk diffusion method. We found that the AuNPs were monodisperse, stable and not prone to aggregation with an average size of 22.12 nm and an emission band at 522 nm. The disk diffusion tests revealed that the gold nanoparticles did not have a significant growth inhibitory effect on the pathogens tested. In conclusion, here we showed the successful synthesis of gold nanoparticles by a safe and non-toxic method. Furthermore, our evaluation of the antimicrobial activity of these nanoparticles suggests that these molecules could be considered as biologically safe molecules for future medical applications.
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