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Search Results: 1 - 10 of 3057 matches for " Hasan Gok "
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P-wave Dispersion for Predicting Paroxysmal Atrial Fibrillation in Acute Ischemic Stroke
Umuttan Dogan, Ebru Apaydin Dogan, Mehmet Tekinalp, Osman Serhat Tokgoz, Alpay Aribas, Hakan Akilli, Kurtulus Ozdemir, Hasan Gok, Betigul Yuruten
International Journal of Medical Sciences , 2012,
Abstract: Background: Detection of paroxysmal atrial fibrillation (PAF) in acute ischemic stroke patients poses diagnostic challenge. The aim of this study was to predict the presence of PAF by means of 12-lead ECG in patients with acute ischemic stroke. Our hypothesis was that P-wave dispersion (Pd) might be a useful marker in predicting PAF in patients with acute ischemic stroke. Methods: 12-lead resting ECGs, 24-hour Holter recordings and echocardiograms of 400 patients were analyzed retrospectively. PAF was detected in 40 patients on 24-hour Holter monitoring. Forty out of 360 age and gender matched patients without PAF were randomly chosen and assigned as the control group. Demographics, P-wave characteristics and echocardiographic findings of the patients with and without PAF were compared. Results: Maximum P-wave duration (p=0.002), Pd (p<0.001) and left atrium diameter (p=0.04) were significantly higher in patients with PAF when compared to patients without PAF. However, in binary logistic regression analysis Pd was the only independent predictor of PAF. The cut-off value of Pd for the detection of PAF was 57.5 milliseconds (msc). Area under the curve was 0.80 (p<0.001). On a single 12-lead ECG, a value higher than 57.5 msc predicted the presence of PAF with a sensitivity of 80% and a specificity of 73%. Conclusion: Pd on a single 12-lead ECG obtained within 24 hours of an acute ischemic stroke might help to predict PAF and reduce the risk of recurrent strokes.
Development of Problem Solving Confidence Questionnaire: Study of Validation and Reliability [PDF]
Tolga Gok
Latin-American Journal of Physics Education , 2012,
Abstract: This study aimed to develop and validate a problem solving confidence questionnaire which would help teachers, instructors, and researchers to have better understanding of problem solving confidence of students. The participants of this scale were 950 undergraduate science and engineering students enrolled in the Introductory Calculus Based Physics. The development of the scale included the following three steps; item formulation, content validation and reliability calculation. The scale has 20 items allocated to two factors: (1) High Confidence; (2) Low Confidence. The scale items had a factor loading of at least .40. The results of the factor analysis revealed that the scale accounted for the 57.32% of the total variance. The alpha reliability coefficient was .92. According to these findings, the Problem Solving Confidence Questionnaire (PSCQ) is a valid and reliable instrument that can be used in the field of engineering and science education.
A new approach: Computer-assisted problem-solving systems
Tolga GOK
Asia-Pacific Forum on Science Learning and Teaching , 2010,
Abstract: Computer-assisted problem solving systems are rapidly growing in educational use and with the advent of the Internet. These systems allow students to do their homework and solve problems online with the help of programs like Blackboard, WebAssign and LON-CAPA program etc. There are benefits and drawbacks of these systems. In this study, the drawbacks of this software were examined. Unfortunately, this software is insufficient to completely improve students’ fundamental and conceptual understanding and problem solving completely. In this paper, problem solving is viewed as a fundamental part of learning physics, and due to the drawbacks of other software, IPSS (Integrated Problem Solving Strategy Steps) was developed for problem solving on the computer. Using the IPSS method, the number of attempts for correct answer was eliminated to focus the students’ attention on getting the correct answer with the full solution. Students’ opinions toward IPSS were taken. According to their declarations, it seems that students found the program helpful for their learning on a conceptual basis.
The General Assessment of Problem Solving Processes in Physics Education
Tolga Gok
Eurasian Journal of Physics and Chemistry Education , 2010,
Abstract: Problem solving is one of the primary tools for college and university science instruction. In this study, the review of problem solving and metacognition skills of students was presented. Basically, at the first step, problem solving was defined and then the differences of the experienced and inexperienced problem solvers were considered. Various strategy steps of problem solving reported in the open literature were discussed. Metacognition was introduced as an important part of problem solving process. The research available in the literature indicated that teaching problem solving strategies help students but not sufficient to promote true science expertise. Meta-cognitive skills should be clearly taught to build structured knowledge and develop desirable habits of mind, and to guide students through the stages of cognitive development.
Does FMF have a property to protect children from obesity?  [PDF]
Faysal Gok, lsmail Dursun, lbrahim Gokce
Health (Health) , 2010, DOI: 10.4236/health.2010.23038
Abstract: Objectives: This study investigates the prevalence of obesity in children with familial Mediterranean fever (FMF). Material and Methods: We retrospectively reviewed the medical records of 70 patients with FMF whose cases had been followed in our Pediatric Nephrology and Rheumatology Unit. The height and weight measurements of children with FMF were obtained and body mass index was calculated. Results: The mean body mass index was 16.7± 2.4 in the boys, and 17.4±2.9 in the girls. Nine of the children (five boys, four girls) were found to be overweight, a rate of 12.8% in FMF patients. Obesity was not detected in FMF patients. Conclusions: We think that there are some unligteening molecular mechanisms that prevent obesity in FMF patients. Due to the limited number of patients in this study, further research involving more patients are needed.
Effect of Sowing Date and Varieties on Essential Oil Ratio and Essential Oil Components of Coriander (Coriandrum sativum L.) in Van Ecological Condition
Bunyamin Yildirim,Nihat Gok
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.1925.1929
Abstract: This study was carried out as random blocks experiment design that three recurrent in Van ecological condition in 2009 infour sowing time (April 5 and 20, May 5 and 20) which to determine essential oil ratio and components of one local coriander population and two coriander varieties. The highest essential oil ratio was obtained as 0.45% from Gurbuz variety. The highest essential oil ratio was obtained as 0.5% from May 20 sowing time. In terms of essential oil it was no different in varieties and in sowing times. The essential oil yield average yields changed from 0.09-0.116 L ha-1. Linalool which essential oil component ratio was changed from 68.3-74.8%. Gamma terpinen ratio was changed from 7-8%. The highest gamma terpinen ratio was obtained as 8.8% from April 20 sowing time.
Ejecta detection in the middle-aged Galactic supernova remnant G296.1-0.5 observed with Suzaku
F. Gok,A. Sezer
Physics , 2011, DOI: 10.1111/j.1365-2966.2011.19822.x
Abstract: In this paper, we report the detection of ejecta in the middle-aged Galactic supernova remnant G296.1-0.5 with the X-ray Imaging Spectrometer onboard the Suzaku satellite. The spectra of three lobes, north, southeast and southwest and inter-lobe regions, consist of soft (0.3-2.0 keV) emission originated from non-equilibrium ionization plasma. In north, southeast and inter-lobe regions, the thermal emission can be represented by a one-component, in southwest region it can be represented by two- component non-equilibrium ionization (VNEI) model. The spectra of studied regions have lines of N, O, Ne, Mg and Si elements. Si emission from this remnant is shown for the first time in this work. Enhanced abundances of Ne, Mg and Si elements obtained show the ejecta contribution in all regions. Assuming that the remnant is in Sedov phase, we obtained ambient density n0 ~ 0.45 cm-3, age t ~ 2.8 x 104 yr, shock velocity Vs ~ 320 km s-1, shock temperature Ts ~ 1.2 x 106 K, and swept-up mass Msw ~ 340 M at an adopted distance of d=3 kpc.
A deep X-ray observation of supernova remnant G304.6+0.1 (Kes 17) with Suzaku
F. Gok,A. Sezer
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.20948.x
Abstract: In this paper, we present the analysis of a deep (99.6 ks) observation of G304.6 + 0.1 with the X-ray Imaging Spectrometer on board {\it Suzaku} satellite. The X-ray spectral data are well-fitted with a plasma model consisting of a thermal component in collisional ionization equilibrium and a non-thermal component. The thermal emission is well fitted with VMEKAL model with an electron temperature of $kT_{\rm e}\sim 0.75$ keV, a high absorbing column density of $N_{\rm H}\sim 3.9\times10^{22}$ $\rm cm^{-2}$ and near/lower solar abundances which indicate that the X-ray emitting plasma of G304.6 + 0.1 is dominated by swept-up ambient medium. The non-thermal component is well fitted with a power-law model with photon index of $\Gamma \sim 1.4$. We found a relatively high electron density $n_{\rm e}\sim 2.3f^{-1/2}$ cm$^{-3}$, age $t$ $\sim 1.4\times10^4f^{1/2}$ yr, and X-ray emitting mass $M_{\rm x}\sim 380f^{1/2}$ {M\sun} at an adopted distance of d=10 kpc. Using the morphological and spectral X-ray data, we confirm that the remnant is a new member of mixed-morphology supernova remnants.
Suzaku study of centrally brightened supernova remnant G272.2-3.2
A. Sezer,F. Gok
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.20570.x
Abstract: In this work, the results from Suzaku observation of Galactic supernova remnant G272.2-3.2 are presented. Spectra of G272.2-3.2 are well fitted by a single-temperature variable abundances non-equilibrium ionization (VNEI) model with an electron temperature kTe \sim 0.77 keV, ionization timescale {\tau} \sim 6.5 \times 10^10 cm-3 s and absorbing column density NH \sim 1.1 \times 10^22 cm-2. We have detected enhanced abundances of Si, S, Ca, Fe and Ni in the center region indicating that the X-ray emission has ejecta origin. We estimated the electron density ne to be \sim0.48f^-1/2 cm-3, age \sim4300f^1/2 yr and the X-ray total mass Mx = 475f^1/2 M by taking the distance to be d=10 kpc. To understand the origin of the centrally-peaked X-ray emission of the remnant, we studied radial variations of the electron temperature and surface brightness. The relative abundances in the center region suggest that G272.2-3.2 is the result of a Type Ia supernova explosion.
Fe-rich ejecta in the supernova remnant G352.7-0.1 with Suzaku
Aytap Sezer,Fatma Gok
Physics , 2014, DOI: 10.1088/0004-637X/790/1/81
Abstract: In this work, we present results from a $\sim$201.6 ks observation of G352.7$-$0.1 by using the X-ray Imaging Spectrometer onboard {\it Suzaku} X-ray Observatory. The X-ray emission from the remnant is well described by two-temperature thermal models of non-equilibrium ionization with variable abundances with a column density of $N_{\rm H}$ $\sim$ 3.3$\times$10$^{22}$ cm$^{-2}$. The soft component is characterized by an electron temperature of $kT_{\rm e}$ $\sim$ 0.6 keV, an ionization time-scale of $\tau$ $\sim$ 3.4$\times$10$^{11}$ cm$^{-3}$ s, and enhanced Si, S, Ar, and Ca abundances. The hard component has $kT_{\rm e}$ $\sim$ 4.3 keV, $\tau$ $\sim$ 8.8$\times$10$^{9}$ cm$^{-3}$ s, and enhanced Fe abundance. The elemental abundances of Si, S, Ar, Ca, and Fe are found to be significantly higher than the solar values that confirm the presence of ejecta. We detected strong Fe K-shell emission and determined its origin to be the ejecta for the first time. The detection of Fe ejecta with a lower ionization time-scale favor Type Ia origin for this remnant.
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