Browsing by Author "Keskin, S."

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Calculation of Power in Chi-Square and Likelihood Ratio Chi-Square Statistics by a Special Sas Macro
(2006) Özdemir, T.; Keskin, S.; Çak, B.
The goal of this study was relatively analyzed as to power in Chi-Square and Likelihood Ratio ChiSquare Statistics by using SAS special macro which is presented in Appendix. For the aim, data sets regarding questionnaire responses of 107 refugees were utilized. Contrary to other data sets (had power values with high-level), sample size for only data set 3 having power values with low-moderate level for both statistics were artificially increased from backward to forward and optimum samples sizes for Ch-Square and other were determined as 280 and 170, respectively. As a result, it was concluded that power of Chi-Square and Likelihood Ratio Chi-Square Statistics changed to some factors: the size of sample and combinations of all cells' frequencies of contingency table. Besides, it is possible that researchers can determine sample size which is suitable for each data set by means of special SAS macro in appendix. Moreover, ones should not forget that power concept in any statistic technique means reliability. © 2006 Asian Network for Scientific Information.
Canonical Correlation for Some Body Traits of Angora Goats
(indian veterinary Journal, 2007) Daskiran, I.; Keskin, S.; Kizilkaya, K.; Bingol, M.
The objective of this study was to determine combinations of the six-month age body weights and body measurements associated with combinations of the monthly body weights until weaning weight in Angora goat.
Classification Tree for Low Birth Weight Rate of Calves
(2009) Mirtagioglu, H.; Keskin, S.; Bakir, G.
The aim of study was to determine effects and interactions of age of first insemination, first calving age, calving age, calving interval, lactation order, dry period, calving month and sex of calf variables on low birth weight rate in calves by using of Classification tree (CT) method. For this the observations obtained from 596 animal materials were used. As a result, calving interval, calving age and calving month were found as significant predictor variables for low birth weight rate of female calves. On the other hand, none of these (calving interval, calving age and calving month) variables was found as significant for male calves.
Comparison of Growth Models in Norduz Female Kids
(indian veterinary Journal, 2007) Keskin, S.; Daskiran, I.
Growth is one of the important characteristics in livestock. Genetic and environmental factors have important effect on growth. Growth rate is not same in the life period of animals. Determinations of various growth parameters,such as body weight, body length and heart depth at different ages are quite important for selection-of animals at early phases of growth. Manipulation of selection due to these parameters helps to determine suitable management and feeding regimens and to decide optimal age at which animals can be used for production purposes (Bayram et al., 2004; Kor et al., 2006). Some authors (Lawrence and Fowler, 2002; Landgraft et al., 2002) informed that growth curve parameters can be also used as direct breeding criteria in improving some of the growths associated traits in addition to describing growth in animals. The aim of this study was to estimate the growth function of Norduz goats at early phases for regulation of the growth intensity, attaining adequate growth and development by feeding regimes and solving some herd management problems.
Determination of the Effective Factors for 305 Days Milk Yield by Regression Tree (Rt) Method
(2010) Bakir, G.; Keskin, S.; Mirtagioglu, H.
The purpose of this study was to determine the effects of dry period, lactation parity, farm, calving season and age on 305 days milk yield using Regression Tree (RT) method. For this purpose 3315 data of 735 Holstein-Friesian raised in Ceylanpinar, Reyhanli and Tahirova State Farms were analyzed. Dry period-lactation parity and farm-calving season and calving age were determined to affect 305 days milk yield at the first, second and third degree factors, respectively. The 305 days milk yield was affected by dry period, calving age and season and being of the dry period around ideal period (60 days) affected milk yield positively. It was suggested that dry period should be around 60 days and some precautions to decrease the adverse effects of heat on milk yield are required to be taken. © Medwell Journals, 2010.
The Effect of Social Anxiety on Student Interactions in Asynchronous Online Discussion Forums as Mediated by Social Presence and Moderated by Anonymity
(Springer, 2024) Demir, O.; Keskin, S.; Cinar, M.
Pervasive internet use in higher education has rendered social anxiety a lesser problem in circumventing interactions. However, the attenuation of vitality in interactions still remains a contentious issue, especially in asynchronous online discussions. This study aims to elucidate how anonymity and social presence affect the relationship between avoidance of interaction and peer and content interaction in online discussions. In the true experimental study, we recruited 123 first-year university students, of which 62 were randomly assigned to the anonymous group, and 61 to the identified group. This paper adopts a moderated mediation model, in which anonymity and social presence are included as moderator and mediator, respectively. We revealed that the “straightforward” relationship between avoidance of interaction and peer and content interaction is actually highly complex. The results substantiate a full mediation of social presence and moderation of anonymity in favor of disclosed identity. This study accentuates the critical role of social presence in fostering interactions. The results also suggest that disclosing discussants’ identities might be useful during asynchronous interactions in online discussions for increasing social presence only if their avoidance of interaction is low; in the case of a high avoidance of interaction, anonymity should be preferred. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Effects of Different Progestins in Oral Contraceptives on Sexual Function and Well-Being of Women
(Yuzuncu Yil Universitesi Tip Fakultesi, 2015) Çetin, O.; Keskin, S.; Verit, F.F.; Yücel, O.
To compare the effects of different progestins in combined oral contraceptives (COC) on sexual functions and well-being of women. In this prospective and observational study, 52 participants used drosperinone, 48 participants used gestodene, 55 participants used levonorgestrele and 60 participants used non- hormonal contraception. All participants completed the Female Sexual Function Index (FSFI) and Beck Depression Inventory (BDI) at baseline and after six cycles of treatment. There was a statistically significant improvement between FSFI scores at baseline and after six cycles of treatment compared with each other. There was no significant difference between FSFI scores compared with each other. In the hormonal contraception group, there was a statistically significant increase between BDI scores at baseline and after six cycles of treatment. In each hormonal contraception subgroup, there was no significant difference between BDI scores. These data show that COC pills make positive effects on female sexuality. Androgenic or antiandrogenic progestins have similar improvements on female sexual function. In addition, COC pills have negative impacts on depression. © 2015 Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
The Effects of Radiotherapy on Arterial Diameters in Patients With High-Grade Glial Tumors Who Have Undergone Adjuvant Radiotherapy
(Wolters Kluwer Medknow Publications, 2023) Karaca, F.; Mentes, S.; Boga, Z.; Akkaya, H.; Keskin, S.; Gulek, B.
Background and Aims:Our purpose was to evaluate the M2 branch of the middle cerebral artery (MCA) in high-grade glial tumor patients who undergo adjuvant radiotherapy (RT). For this purpose, the diameter of the M2 branch was measured and evaluated by means of contrast-enhanced magnetic resonance imaging (CE-MRI) before and after RT. Post-radiotherapeutical measurements were made 1, 3, 5, and 7 months after the procedure; and vascular diameter alterations were evaluated. Materials and Methods:CE-MRI examinations were performed on the 32 patients enrolled in the study, who had undergone radiotherapy of the temporoparietal region. MRI examinations were performed prior to RT (RT0) and 1 (RT1), 3 (RT2), 5 (RT3), and 7 (RT4) months after RT. The M2 branch of the MCA was evaluated on MRI images, and the vessel diameter was measured in millimeters (mm), and then comparisons were made. Results:Statistically significant results were obtained during RT0-RT1, RT0-RT2, RT0-RT3, RT0-RT4, RT1-RT2, RT2-RT4, and RT3-RT4, and comparisons of the diameters of the M2 branch of the right MCA were performed (P < 0.05). When the same measurements and comparisons were made for the M2 branch of the left MCA, statistically significant results were found for the RT1-RT2, RT1-RT3, and RT1-RT4 comparisons (P < 0.05). Conclusion:Our study showed that the MCA M2 branch diminished in size following RT. This was demonstrated by means of CE-MRI controls performed up to 7 months after the completion of the RT procedures.
Estimation of Parameters of Linear and Nonlinear Growth Curve Models at Early Growth Stage in California Turkeys
(Eugen Ulmer Gmbh Co, 2007) Ersoy, I. E.; Mendes, M.; Keskin, S.
This study was designed to investigate growth characteristics of totally 194 California turkeys (98 male, 96 female) using their weight-age data at early growth stage (during first 10 weeks). Linear, Logistic with three parameters and Richards' growth models were applied to estimate growth parameters. Results of analyses showed that both Logistic and Richard's growth models fitted weight and age data very well with R-2 = 99.3% and 99.4% for males and R-2 = 99.2% and 99.3% for females. Mature weights of males and females estimated using Logistic growth (2,228 +/- 55.3 g and 2,011 +/- 54.4 g) model and Richard's growth model (2,195 +/- 62.5 g and 1,973 +/- 59.9 g) was similar. In the case of the estimate on the change of body weights of male and female turkeys by equations W-t = -196.22 + 275.98t and W-t = -169.50 + 246.28t using the linear model, the k2 values of the estimates were 93.8% and 94.0%. R2 values in the linear model were smaller than those in the Logistic and Richards's models. When comparison is done based on the other criteria (Jp, AIC, BIC, DW, and asymptotic correlation), Logistic and Richard's growth models can be assumed to be more appropriate to estimate growth characteristics of young turkeys. On the other hand, among these growth curve models the logistic model can give the most reliable estimates of growth parameters of turkeys at early stage of life.
Evaluating Interleukin-16 Expression in Patients With Grade-3 and Grade-4 Glial Cell Tumors and Healthy Individuals
(Wolters Kluwer Medknow Publications, 2023) Karaca, F.; Keskin, S.; Mentes, S.; Boga, Z.; Cavus, G.; Koksal, F.
Background: This study evaluated the change in IL-16 levels in patients with high-grade glial tumors undergoing radiotherapy (RT) and healthy individuals (control group).Materials and Methods: Serum IL-16 levels of 35 high-grade glioma patients receiving radiotherapy (RT) and 30 healthy individuals were compared. We compared the IL-16 levels before (RT0) and after the (RT1) and IL-16 levels were measured and the relationship of this change with other characteristics such as age, gender, weight, height, and blood test results. Results: The RT0-IL-16 level was approximately 15 pg/ml higher than the RT1 measurement in the patient group. The mean RT0-IL-16 levels in the patient group were approximately 10 pg/ml higher than the mean IL-16 levels in the control group. Likewise, at the RT1 time-point, the mean IL-16 levels for the patient group were approximately 5 pg/ml lower than the mean IL-16 for the control group. The mean RT0-RT1-IL-16 value tended to be higher in female patients than in male patients. Conclusion: The application of RT reduces the overall IL-16 levels, suggesting the efficacy of RT, as well as the role of IL-16 in tumorigenesis.
Evaluation of Fatigue in Behçet's Syndrome; Relationship With Disease Activity, Clinical Manifestations, Anxiety, Depression, and Daily Living Activities
(2010) Karaaslan, G.; Hiz, O.; Ediz, L.; Tekeoǧlu, I.; Keskin, S.
Objective: The aim of this study was to assess fatigue in patients with Behcet's Syndrome and to identify the relationship between fatigue and clinical signs, psychological status and activities of daily living in these patients. Material and Methods: Seventy-six Behcet's Syndrome (BS) patients who were diagnosed with at least one year and the same number of healthy control subjects with similar demographic features were included in the study. Multidimension Assessment of Fatigue (MAF) used for evaluation of fatigue in both groups. In addition, hospital depression and anxiety scale and short form 36 were filled by the patients. Results: A negative correlation between level of education and the degree and severity of fatigue was found, while there was a positive correlation between disease duration and degree and severity of fatigue, and the global score. Threre was correlation between clinical signs of Behcet's disease and some sub-groups of the MAF, however the global score was not significantly correlated. Statistically significant high scores of MAF values were found in patients with BS in comparison with the control group. There was a positive correlation between anxiety, depression and fatigue values in patients with BS. Negative correlation determined between all parameters of daily living quality (SF-36) and fatigue values of the patients. Conclusion: Fatigue is common in BS and closely associated with psychological status and affects negatively activities of daily living. Therefore, it should be taken into account in the evaluation of BS patients. Copyright © 2010 by Türk Tibbi Rehabilitasyon Kurumu Derneǧi.
Evaluation of Hematologic and Biochemical Parameters in Patients With Early Stage Uterine Malignancy Receiving Radiotherapy
(Yuzuncu Yil Universitesi Tip Fakultesi, 2018) Karaca, F.; Menteş, S.; Keskin, S.
Surgery is the primary choice of treatment for this disorder. Radiotherapy is an important step of treatment in this cancer after surgery due to the stage of the disease. Lack of prospective randomised data for survival limits the use of adjuvant radiotherapy. Hovewer adjuvant radiotherapy is suggested for high risk patients to reduce locoregional recurrence. The aim of this study is to define the statistical difference of hemogram, transaminases, kidney function tests and electrolyte changes in patients before starting radiotherapy, the end of radiotherapy, with the onset of acute side effects, and three months after finishing radiotherapy with the onset of chronic side effects. 18 patients with early stage endometrial malignancy attending to Adana Numune Training and Research Hospital have been included. This study has assessed the changes in hemogram, blood transaminases, urea, creatinin and electrolyte values of patients before radiotherapy, at the last week of radiotherapy and three months after radiotherapy. The values were statistically significant for AST, Ca, LDH, urea, Hb and HTC values before treatment, at the end of the treatment and three months after treatment (p<0.05). The effect of radiotheraphy seen as lower values of hemoglobin and hematocrite in endometrial malignancy patients resolved and become normal after three months of the radiotherapy. © 2018, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Evaluation of Il-17a Expressions in High-Grade Glial Tumors Receiving Radiotherapy
(Wolters Kluwer Medknow Publications, 2022) Karaca, F.; Keskin, S.; Mentes, S.; Okten, A., I; Cavus, G.; Arslan, A.; Koksal, F.
Aim: In this study, we aimed to investigate the interleukin-17A (IL-17A) levels in patients with high-grade glial tumors before receiving radiotherapy, immediately after radiotherapy, and 3 months after radiotherapy. Patients and Methods: A total of 33 patients who applied to Adana City Training and Research Hospital, Department of Radiation Oncology between December 2016 and May 2018 was included in this study. A total of three blood samples was taken from each patient to assess IL-17A levels before and after radiotherapy and 3 months after the completion of radiotherapy. Results: The differences in IL-17A levels between genders were not statistically significant. IL-17A levels progressively decreased after the radiotherapy and 3 months after the radiotherapy as compared to the levels before radiotherapy. However, this was not statistically significant. IL-17A levels in the non-surviving patients were high before and after radiotherapy as compared to the surviving ones, but this was also not statistically significant. Conclusion: As compared to the period before radiotherapy, IL-17A levels tend to decrease in the period of acute and chronic phases of radiotherapy in all patient groups.
Evaluation of Relationships Between Postural and Functional Lateral Preferences and Chewing Side Among Students in Eastern Turkey
(Yuzuncu Yil Universitesi Tip Fakultesi, 2019) Erkec, O.E.; Keskin, S.
This study aims to evaluate the relationships between postural and functional lateral preferences and the preferred chewing side among young subjects. Functional lateral preferences, postural lateral preferences and the preferred chewing side were assessed in 376 young individuals (178 men, 198 women, mean age: 20.07). Of the 376 individuals, 31.1 % were strong right-handers, 58.8 % were weak right-handers, 2.9% were ambidextrous, 5.9% were weak left-handers, 1.3% was strong left-handers. There was a right-side preference for handedness (89.9%), footedness (75.8%), earedness (59.2%), eyedness (paper tube test, 70.0%), eyedness (Rosenbach dominant eye test, 62.9%), hand clapping (78.4%), leg-crossing (64.4%), preferred chewing side (60.9%) and a left-side preference for hand-clasping (55.2%), and arm-folding (55.3%). Only eyedness (paper tube test) differed between the genders; women mostly preferred the left eye when looking through the paper tube. Handedness, footedness, earedness, and eyedness (paper tube) were each related with hand-clapping, however not with hand clasping and arm folding. In addition, hand clapping and leg crossing (but not hand clasping and arm folding) were each related to preferred chewing side. In general, individuals who preferred the right side were right sided in all of the variables, while individuals who preferred the left side were closely related to individuals who preferred both sides. Thus, it can be concluded that individuals who preferred the left side tended to be mostly bilateral, compared with individuals who preferred only the right side. These results may bring insight into the relationships between functional and postural lateral preferences and the preferred chewing side for the young population. © 2019, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Evaluation of Sensory Characteristics of Sheep and Goat Meat by Procrustes Analysis
(Czech Academy Agricultural Sciences, 2012) Keskin, S.; Kor, A.; Karaca, S.
Relationships between sensory variables, species, feeding systems, and panelists were examined by Procrustes Analysis. Six meat groups considering species and feeding type combinations were evaluated by ten panelists for five sensory characteristics (colour, texture, odour, taste, and acceptability). These characteristics were assessed using a nine-point hedonic scale (9 = extremely enjoy, 1 = extremely dislike). Generalized Procrustes Analysis was performed and 61.11% of the total variability was explained by the first two dimensions that correspond to Factor 1 and Factor 2. The first one accounted for 33.99% and the second for 27.12%. Results showed that pasture conditions were reflected in all sensory characteristics of meat of Hair goat as well as Karakas sheep. This study concluded that meat of sheep and goats reared in pasture conditions was more preferable as concerns sensory characteristics than that of fattening animals or those reared in intensive conditions.
Factors Affecting the Number of Fatalities and Injuries in Motor Vehicle Accidents in Turkey
(Yuzuncu Yil Universitesi Tip Fakultesi, 2024) Aşırdizer, M.; Etli, Y.; Keskin, S.
Reducing traffic-related deaths and injuries by 50% by 2030 is the main objective of the General Assembly of the United Nations in 2020. The current study aimed to investigate the characteristics of motor vehicle accidents (MVAs) that occurred between 2013 and 2022 in Turkey and the factors influencing the number of injuries and fatalities in these MVAs, to determine how close this target is. Crude data for the study was taken from the Turkish Statistical Institute's (TUIK) public website. To enable secure comparisons, these crude data were proportionately standardized for this study. Both the number of MVAs per 1,000 registered vehicles and the number of injured and deceased victims per 100,000 people in Turkey decreased after peaking in 2015. Urban regions contributed to 76.2% of the MVAs which resulted in injuries and fatalities. Males accounted for 76.9% of all fatalities, 69.4% of all injured victims, 97.7% of dead drivers, and 92.5% of injured drivers. While most injuries and deaths occurred between the ages of 25 and 64, the highest risk of death was observed among individuals aged 65 and older in comparison with the 100,000 people. Most of the fatalities and injuries in MVAs happened in August, during weekends and daylight hours. Twilight MVAs had the highest fatality risk. Automobile MVAs were the most common cause of all MVAs, injuries, and deaths. Drivers were accountable for 88.5% of the faults that caused MVAs. In Turkey, the frequency of MVAs, together with the number of injuries and fatalities sustained, continues to be comparatively high. Therefore, a road safety committee should be established, and an emergency action plan for safe road vehicle traffic in Turkey should be designed. © 2024, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Gastrıc İntestınal Metaplasıa And Covıd 19 İnfectıon
(Yuzuncu Yil Universitesi Tip Fakultesi, 2020) Aydın, M.; Dülger, A.C.; Özer, S.; Dirik, Y.; Keskin, S.; Demir, C.
Gastric intestinal metaplasia (GIM) is defined as immigration of enteric or colonic mucosa within gastric lining.Gastric intestinal metaplasia (GIM) is a premalign condition seen in gastric lining. It is prevalent in Asia and may lead to gastric carcinoma at a rate of 1% annually. COVID 19, which has been a global issue since late 2019, causes mostly respiratory symptoms; however, some patients may present with gastrointestinal symptoms including diarrhea, vomiting (5%) and abdominal pain (3.8%).We tried in this text to handle any possible association between COVID 19 infection and GIM. In this retrospective study we included 39 COVID 19 patients and 180 age-matched control subjects to compare rate of intestinal metaplasia. All statistical analyses were performed with SAS software (SAS Institute, Cary, N.C.). The clinical and radiological characteristics of patients were compared using Student's t-test. Intestinal metaplasia was found in 11 (28%) of 39 patients while in 7 (3,9%) of 181 controls, which meant a statistical significance (p<0,05). Of the 181 subjects, atrophy was found in 39 (21%) whereas it was noted in 9 (23%) of 39 patients, which yielded no statistical significance (p>0,05). We found that GIM is a premalignant condition that can lead to COVID 19 infection. © 2020, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Introduction of Nonlinear Principal Component Analysis With an Application in Health Science Data
(Yuzuncu Yil Universitesi Tip Fakultesi, 2022) Demir, C.; Keskin, S.
Nonlinear Principal Component Analysis is one of the explanatory dimension reducing technique and presents numerical and graphical results for variable set included linear or nonlinear relationships. In this study, Nonlinear Principal Components Analysis was introduced and the relationship between students' sexual and physical trauma stories and demographic characteristics was examined with this method. In the study, the relationship between trauma and 9 variables obtained by questionnaire from 548 students was evaluated by non-linear principal components analysis. The total eigenvalue of first dimension has been found to be 1.766 and the total eigenvalue of second dimension ha s been found to be 1.504 The variance explanation rate of these eigenvalues are 17.656% and 15.044% respectfully. The total explained variance is seen as 28.550%. With nonlinear principal component analysis, categorical variables are scaled to the desired size in the most appropriate way, and thus, nonlinear relationships can be modeled as well as linear relationships between variables. With this analysis, gender, age, marital status and suicide variables were found to be effective on trauma. © 2022, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.
Online Learners’ Navigational Patterns Based on Data Mining in Terms of Learning Achievement
(Springer International Publishing, 2019) Keskin, S.; Sahin, M.; Yurdugül, H.
The aim of this study is to explore navigational patterns of university students in a learning management system (LMS). After a close review of the literature, a scarcity of research on the relation between online learners’ navigational patterns and their learning performance was found. To contribute to this research area, the study aims to examine whether there is a potential difference in navigational patterns of the learners in terms of their academic achievement (pass, fail). The data for the study comes from 65 university students enrolled in online Computer Network and Communication. Navigational log records derived from the database were converted into sequential database format. According to students’ achievement (pass, failure) at the end of the academic term, these data were divided into two tables. Page connections of the users were transformed into interaction themes, namely homepage, content, discussion, messaging, profile, assessment, feedback, and ask the instructor. Data transformed into sequential patterns by the researchers were organized in navigational pattern graphics by taking frequency and ratio into consideration. The z test was used to test the significance of the difference between the ratios calculated by the researchers. The findings of the research revealed that although learners differ in terms of their achievement, they draw upon similar processes in the online learning environments. Nevertheless, it was observed that students differ from each other when considering their system interaction durations. According to this, learning agents, interventional feedbacks, and leaderboards can be used to keep failed students in the online learning environment. Studies were also proposed on the ordering of these LMS navigational themes, which are important in the e-learning process. Findings from these studies can guide designers and researchers in the design of adaptive e-learning environments, which are also called next-generation digital learning environments. © Springer Nature Switzerland AG 2019.
Online Learners' Navigational Patterns Based on Data Mining in Terms of Learning Achievement
(International Conference on Cognition and Exploratory Learning in Digital Age, 2016) Keskin, S.; Sahin, M.; Ozgur, A.; Yurdugul, H.
The aim of this study is to determine navigational patterns of university students in a learning management system (LMS). It also investigates whether online learners' navigational behaviors differ in terms of their academic achievement (pass, fail). The data for the study comes from 65 third grade students enrolled in online Computer Network and Communication lesson in a state university. As the online learning environment, Moodle, an open source software, is used in this study. Navigational log records derived from database were converted into sequential database format. According to students' achievement (pass, failure) at the end of the academic term, these data were divided in two tables. Page connections of the users were transformed into interaction themes namely, homepage, content, discussion, messaging, profile, assessment, feedback and ask the instructor. Data transformed to sequential patterns by the researchers were organized in navigational pattern graphics by taking frequency and ratio into consideration. To test the difference between obtained patterns ratio test was conducted by means of z statistics. The findings of the research revealed that first and second order navigational patterns of passed and failed students in the online learning environment had similar features, but passed students allocated more time to interaction process.