Browsing by Author "Yesilova, Abdullah"

Now showing 1 - 12 of 12

A Comparison of Hot Deck Imputation and Substitution Methods in the Estimation of Missing Data
(Gazi Univ, 2011) Yesilova, Abdullah; Kaya, Yilmaz; Almali, M. Nuri
It is of great importance to obtain data in an accurate and incomplete way for adequate conclusions to be drawn from investigations conducted. Due to various reasons, certain parts of an investigation might not be observed, and as a result of this, data might be missing and obtained incompletely. Missing value may not only be based on a single variable but also a multitude of variables. In this study, missing data in different proportions and belonging to more than a variable were produced. When data were considered within a context which is missing completely at random, Hot Deck imputation, random Hot Deck imputation and substitution methods (mean, median) were compared in the estimation of missing value. As a result of analysis, Hot Deck imputation method was found to be more effective in the estimation of missing value.
Detection and Comparison of Neuraminidase Activities in Human and Bovine Group B Streptococci
(Wiley-blackwell, 2016) Ekin, Ismail Hakki; Gurturk, Kemal; Ilhan, Ziya; Ekin, Suat; Borum, Ayse Ebru; Arabaci, Cigdem; Yesilova, Abdullah
Human and bovine group B streptococcus (GBS) isolates were serotyped and amounts of released N-acetylneuraminic acid from N-acetylneuraminyl-lactose by extracellular neuraminidase were colorimetrically assessed. According to serotyping by co-agglutination method, 30 of bovine GBS and 43 of human GBS could be serotyped (ST) by monospecific antisera coated with protein A. The remaining GBS strains were designated as nontypeable (NT). The released N-acetylneuraminic acid was determined in 90.9% of bovine GBS and 47.1% of human GBS isolates. The differences between the total bovine and human GBS isolates were statistically significant (p < 0.001). In comparison with detected N-acetylneuraminic acid level in bovine and human groups, significant decrease was observed in the bovine NT group according to increased human NT (p < 0.01) and bovine ST groups (p < 0.01). However, N-acetylneuraminic acid level in bovine ST and bovine total groups significantly (p < 0.001) increased with respect to the human ST group and human total group. Neuraminidase activity was detected more frequently in bovine GBS isolates. Considerable differentiations were observed between typeable and nontypeable isolates.
Investigation of the Effects of Physico-Chemical Environmental Conditions on Population Fluctuations of Notonecta Viridis Delcourt, 1909 (Hemiptera: Notonectidae) in Van Lake by Using Zero-Inflated Generalized Poisson Regression
(Entomological Soc Turkey, Ege Univ, 2011) Yesilova, Abdullah; Ozgokce, Mehmet Salih; Atlihan, Remzi; Karaca, Ismail; Ozgokce, Fevzi; Yildiz, Sukran; Kaya, Yilmaz
In ecological studies, it is a common situation occured that population density of species extremly increases or decreases in certain periods depending on many abiotic and biotic factors. Because of ecologial factors that cause high level fluctuation in population density, It is possible to get zero individual at samplings, and on the other hand, differences between maximum and minimum values obtained in different samplings intervals can be very high. Because this type of data based on counting does not show normal distribution, and shape of the distribution is skewed to the right because of the abundance of zero, using the Zero-inflated Poisson regression method (ZIGP) is required. This study was carried out to obtain information on effects of physico-chemical environmental conditions on population fluctuation of Notonecta viridis. Samplings were conducted with monthly periods along the coastal band of Van Lake in 2005-2006. Samples were taken from 20 sampling places where have three different characters as stream entrances, settlements and natural coastlines. Reults were analysed by using ZIGP regression model. According to results, Effect of sampling intervals and sampling stations on population densities of Notonecta viridis were important. On the other hand, HCO3 had negative effect on population densities in zero-inflated model while it had possitive effect on population densities in other two models. It was determined that Fe effected the species populations in the negative way in the mean regression model, and Cl and Mg effected it in possitive way in the overdispersion regression. In the result, it was deductived that Notonecta viridis was found excessive numbers or none in some sampling stations because of the pysico-chemical structures of water.
Locational Classification of Walnut (Juglans Regia L.) Genotypes Collected From Lake Van Basin by Using Mixture Modeling
(Academic Journals, 2010) Yesilova, Abdullah; Ozrenk, Koray; Kaki, Baris; Almali, M. Nuri; Balta, Fikri
In mixture modeling, it is assumed that the data set shows a heterogeneous structure. This heterogeneity is defined as unobservable heterogeneity. The data set's heterogeneity produces serious deviations in the parameter estimates and the standard deviations. Heterogeneity is overcome when the data set divides itself into homogeneous sub-populations. Thus, while homogeneity is attained for sub-populations, the heterogeneity between the sub-populations is tried to be put forward. Akaike's information criteria (AIC), Bayesian information criteria (BIC), and Entropy classification criteria are used to determine the number of sub-populations. After the number of sub-populations is determined, the model determines the probability that each observation will fall within a particular sub-population. In this study, the classification of districts based on fruit traits is achieved by applying mixture modeling to walnut fruits collected from eight districts. According to the AIC, BIC, and entropy criteria, a model with five sub-populations was chosen where the data set is the most distributed. Therefore, it was determined that each district does not form a different population according to the studied walnut fruit traits, but are distributed into five sub-populations. The fourth sub-population had the most desirable traits for walnut improvement, and the highest proportion of these traits came from the naturally grown populations of Adilcevaz and Ahlat districts.
Meglumine Antimoniate Is More Effective Than Sodium Stibogluconate in the Treatment of Cutaneous Leishmaniasis
(Taylor & Francis Ltd, 2016) Yesilova, Yavuz; Surucu, Hacer Altin; Ardic, Nurittin; Aksoy, Mustafa; Yesilova, Abdullah; Oghumu, Steve; Satoskar, Abhay R.
Sodium stibogluconate (SSG, Pentostam) and meglumine antimoniate (MA, Glucantime) are two antimonials that are widely used to treat cutaneous leishmaniasis (CL), but the relative efficacies of these treatments are not clear. The aim of this study is to compare the efficacy of intralesional SSG with intralesional MA therapy in the treatment of CL. One month after completion of the therapy, 1431 of 1728 patients (82%) who received intralesional MA showed complete clinical cure compared to 1157 of 1728 patients (67%) in the SSG group. Patients who did not respond to the first round of therapy were re-administered the same treatment but with twice weekly injections. Following completion of the second course of therapy, 237 of 297 patients (80%) in the MA group and 407 of 561 patients (72%) in the SSG group healed their lesions by 1-month post-treatment. At both times, the differences in cure rates between MA and SSG groups were statistically significant (p<0.05). Cure rates in the MA group were always significantly higher than SSG groups irrespective of other parameters including age, gender, lesion site and type of lesion. Intralesional MA is more effective than intralesional SSG in the treatment of CL.
Modeling Insect-Egg Data With Excess Zeros Using Zero-Inflated Regression Models
(Hacettepe Univ, Fac Sci, 2010) Yesilova, Abdullah; Kaydan, M. Bora; Kaya, Yilmaz
As zero-inflated observations occur very often in studies on plant protection, models taking into account zero-inflated observations are frequently required. Especially, zero-inflated observations occur in large numbers for insects whose post-oviposition period lasts long, or that generally lay their eggs during the first clays of the oviposition period. For the data used in this study, 1114 (43.84%) of the 2541 observations were zero. In the selection of an appropriate regression model, zero-inflated negative binomial regression was chosen as the best model. In all regression models, the day of laying and the three different hosts were seen to have a significant effect on daily egg numbers (p < 0.01).
Modeling Mite Counts Using Poisson and Negative Binomial Regressions
(Parlar Scientific Publications (p S P), 2016) Yesilova, Abdullah; Denizhan, Evsel
Poisson regression is frequently used for analyzing dependent variable based on count data. The main feature of the Poisson distribution is the assumption that the mean and variance are equal. However, this equal the mean and the variance relationship rarely occurs in application. In many case, the variance is larger than the mean, which is called overdispersion. When overdispersion occurs in a data set, negative binomial regression, in which parameter estimations are obtained by considering the effect that stems from overdispersion, is preferable. In this study, there was overdispersion in the number of mites. Therefore, parameter estimations were interpreted according to negative binomial regression. Effects of all independent variables were statistically significant on number of mites (p<0.01) in the negative binomial regression. The number of mites in Bardakci area was higher than that in Edremit and Samranalti (p < 0.01). Mite density in July was higher than that in other months (p < 0.01). The number of mites in the Golden variety was also found to be less than that in the Starking variety (p < 0.01).
Modeling With Gaussian Mixture Regression for Lactation Milk Yield in Anatolian Buffaloes
(Agricultural Research Communication Centre, 2016) Yesilova, Abdullah; Yilmaz, Ayhan; Ser, Gazel; Kaki, Bads
The purpose of this study was to classify Anatolian buffalo using Gaussian mixture regression model according to discrete and continuous environmental effects. Gaussian mixture model performs separately regression analysis both within and between groups. This is an important property of Gaussian mixture models which makes it different from other multivariate statistical methods. The data were obtained from 1455 Anatolian buffalo lactation milk yield records reared in seven different locations in Bitlis province, Turkey. Age of dam, lactation duration and locations were considered as environmental effects on lactation milk yield. Data set was divided into three homogenous subgroups with respect to AIC and BIC in the Gaussian mixture regression, based on environmental effects on lactation milk yield. Estimated mean for lactation milk yields and mixing probabilities for the first, second and third subgroups were determined as 1494.33 kg (16.9%), 540.33 kg (45.2%) and 847.61 (37.9%), respectively. The numbers of buffalo in each subgroup according to mixing probability were obtained as 159, 756, and 540 for the first, second, and third groups, respectively. The effects of lactation period, age of dam and villages were found statistically significant on lactation milk yield in subgroup 1 that was highest mean for lactation milk yield (p<0.01). In conclusion, results showed that Gaussian mixture regression was an important tool for classifying quantitative traits considering environmental effects in animal breeding.
Modelling of the Arthropod Population Densities in the Coastal Band of Lake Van Using Mixture Poisson Regression
(Parlar Scientific Publications (p S P), 2016) Yesilova, Abdullah; Ozgokce, Mehmet Salih; Atlihan, Remzi; Yildiz, Sukran Polat; Karaca, Ismail; Ser, Gazel
This study is based on periodical surveys of the coastal band of Lake Van. Twenty sampling sites were determined on the basis of 3 different characteristics: stream entrance point, settlement on the coastline, and natural coastline. Macro invertebrates were collected with a standard sweep net, and zooplankton samples were collected using plankton nets. Mixture Poisson regression was used for data analysis. In mixture Poisson modeling, the data set is assumed to have an unobservable heterogeneous structure, causing serious deviations in parameter estimations and standard errors. This heterogeneity is overcome when the data set is divided into homogeneous subpopulations. Thus, homogeneity is achieved for subpopulations but the heterogeneity to be put forward between the subpopulations is unclear. In this study, 20 zooplankton and 7 insect species were found and their populations were separated into 8 subpopulations according to the mixture Poisson regression model. The relationship between species densities and the physicochemical structure of water was statistically significant (p<0.01). In the subpopulations, it was determined that the densities of certain species in areas with the same characteristics were high. This indicates that these species are indicators for these areas.
Pediatric Cutaneous Leishmaniasis in an Endemic Region in Turkey: a Retrospective Analysis of 8786 Cases During 1998-2014
(Public Library Science, 2016) Aksoy, Mustafa; Doni, Nebiye; Ozkul, Hatice Uce; Yesilova, Yavuz; Ardic, Nurittin; Yesilova, Abdullah; Satoskar, Abhay R.
Background Cutaneous leishmaniasis ( CL) is a major public health concern in Turkey and Sanliurfa represents the most endemic city in Turkey. Although children are most commonly affected by CL, detailed studies of pediatric CL in Turkey are lacking. Methodology/Principal Findings In this report we retrospectively evaluated clinical and epidemiological data of 8786 pediatric CL cases, and how children respond to antimonial therapy. CL was observed most frequently in children between 6-10 years old. Interestingly this group showed shorter duration of disease and smaller lesions compared to 0-5 year and 11-15 year old groups. Females were more affected in all groups. Lesion localization and types varied among groups, with 0-5 year old presenting head/neck and mucosal lesions, and more often suffered from recidivans type, this could be associated to the longest duration of the disease in this group. Eleven-15 year old group showed fewer lesions in the head/neck but more generalized lesions. Evaluation of treatment response revealed that intra-lesional treatment was preferred over intramuscular treatment. However, 0-5 year old received intramuscular treatment more often than the other groups. Furthermore, the majority of 0-5 year old group which received intra-lesional treatment did not received subsequent intra-lesional cycles, as did children in the range of 6-15 years old. Conclusions/Significance We report an increase in pediatric CL patients within the last four years. Analysis of pediatric CL patients by age revealed significant differences in CL progression. The data suggest that children between 0-5 years old responded better than other groups to intralesional treatment, since they received more often a single cycle of IL treatment, although follow up observation is required since they were more prone to develop recidivans. Eleven-15 year old patients comprise the largest percentage of patients receiving two or three cycles of intralesional treatment, suggesting that this group did not respond efficiently to intralesional treatment and highlighting the need for more effective therapeutic strategies against CL.
The Prevalence and The Determinants of Contraceptive Use Among Men and Women in Eastern Turkey
(Parlar Scientific Publications (p S P), 2017) Karaaslan, Selver; Sahin, Hanim Guler; Yesilova, Abdullah; Gunbatar, Nizamettin; Keskin, Siddik; Orhun, Reyhan; Akyigit, Elif
A variety of individual and community level determinants affect contraceptive usage. Traditionally the researches focus on women. The aim of this study was to investigate the prevalence and factors that are related to the use of contraception and the choice of contraceptive method among men and women in eastern Turkey which has a high fertility rate. The randomly selected study respondents were privately interviewed face-to-faces. A total of 3292 (676 men and 2616 women) respondents between 15 and 50 years of age were interviewed. The prevalence of the use of any form of family planning was 74%. Male condoms were used by 22.9% of the respondents, followed by intrauterine devices (16.7%), oral contraceptives (13.7%) and withdrawal (13%). Lower education level, maternal age at first birth, belief that lactation protects against getting pregnant, incorrect knowledge about contraceptive methods and efficacy were significantly associated with a preference for using less effective traditional methods (p < 0.05). Governments should focus on increasing the education level of men and women, creating greater awareness of family planning methods and their side effects, and increasing male involvement, which can decrease male opposition and thus increase rates of contraceptive use.
Sexual Behaviour Characteristics in Norduz and Karakas Rams and Changes With Age
(Ankara Univ, Fac Agr, 2009) Yilmaz, Ayhan; Karakus, Ferda; Yesilova, Abdullah
This study was performed to determine the changes of sexual behaviour traits based on age in Norduz and Karakas rams Akkaraman variety. For this purpose, the rams were divided into two groups according to age. First and second group consisted of 3 >= and 2 years old rams, respectively. To determine sexual behaviours, the rams of the first (n=7) and second (n=5) groups were tested individually with 3-5 estrous sheep for 15-min periods in each 2 days. The defined values for anogenital investigations without flehmen, anogenital investigations with flehmen, rising of tail, vocalization, mounts without ejaculation and ejaculations in rams were found as 4.65 +/- 0.53, 2.08 +/- 0.19, 8.58 +/- 0.97, 62.90 +/- 6.30, 38.73 +/- 3.04, 1.29 +/- 0.19, respectively. The least squares mean for mounting duration, ejaculation duration and ejaculation efficiency were found as 0.65 +/- 0.11 min., 5.16 +/- 0.71 min. and 0.05 +/- 0.006, respectively. Over the 4 test days, 3 >= years old rams were superior in terms of rising of tail, the vocalization, ejaculations, ejaculation duration and ejaculation efficiency than 2 years old rams (P<0.05). It was observed that sexual activity test did not provide an improvement in 2 years old rams.