Makale | 2018 | Research in Science Education
This research investigated the effect of problem-based learning (PBL) for the topic of energy metabolism in a biochemistry course on the academic achievements of students studying in the healthcare field in a nursing department. The study had a one-group pre-test and post-test research design. The study group consisted of first-year students studying at the Department of Nursing in the Faculty of Health Sciences at Bulent Ecevit University (N = 210). The scenario, entitled “Emre’s Sports Life: Is It True or False? You Decide!” and consisting of five educational sessions was developed and implemented after taking into account the opi . . .nions of two biochemistry and pedagogical experts. The “Energy Metabolism Achievement Test” (EMAT) and a structured interview form were used as data collection tools. The content analysis of the EMAT post-test indicated that PBL increased students’ responses in the sound and partial understanding categories and the Wilcoxon signed rank test result revealed that there was a significant difference between EMAT pre- and post-test scores in favor of post-test scores (z = - 12.567, p Daha fazlası Daha az
Topuz A. | Engin T. | Alper Özalp A. | Erdoğan B. | Mert S. | Yeter A.
Makale | 2018 | Journal of Thermal Analysis and Calorimetry131 ( 3 ) , pp.2843 - 2863
This paper presents thermal performance and pressure drop characteristics of water-based nanofluids flowing through a horizontal circular microchannel under the constant surface temperature condition, experimentally. Al2O3 (13 nm), TiO2 (10–25 nm) and ZnO (18 nm) nanoparticles with 0.5, 0.7 and 1.0% volume concentrations were used in order to prepare nanofluid. The thermal conductivity and viscosity values needed for the calculations were obtained by measuring separately. For the experiments, the microchannels made by both the different materials (Stainless steel, PEEK) and the different inner diameter (400, 750, 1000 µm) were teste . . .d for the different surface temperatures (283, 298, 313 K). In the tests, the nanofluids had the different inlet temperature (323–333 K), the volume flow rates (20, 35, 50 mL min-1) and the concentrations. Heat transfer rate, Nusselt number, pressure drop and friction factor results were calculated. The optimum conditions were determined by using Taguchi approach. The thermal performance and the pressure drop of the fluids were compared. The results showed that the best thermal performance was obtained for Al2O3 nanofluid with 1.0% vol. concentration. A heat transfer enhancement of 15.3% was achieved using nanofluid instead of deionized water as the base fluid. Moreover, it has been seen no considerable pressure drop. © 2017, Akadémiai Kiadó, Budapest, Hungary Daha fazlası Daha az
Demirdöğen, Betül | Hanuscin, Deborah L | Uzuntiryaki-Kondakçı, Esen | Köseoğlu, Fitnat
Makale | 2016 | Research in Science Education46 ( 4 ) , pp.575 - 612
The purpose of this case study is to delve into the complexities of the early development of preservice chemistry teachers’ science teaching orientations, knowledge of learners, knowledge of instructional strategies, and knowledge of assessment during a two-semester intervention designed to enhance their pedagogical content knowledge (PCK) for teaching nature of science (NOS). Thirty preservice chemistry teachers enrolled in a Research in Science Education course participated in the study. Qualitative data sources included responses to an open-ended instrument, interviews, observations, and artifacts such as lesson plans and reflect . . .ion papers. Through the in-depth analysis of explicit PCK and constant comparative method of analysis, we identified the influence of the intervention on participants’ PCK for NOS. Analysis of data revealed four major themes related to the nature of preservice chemistry teachers’ NOS teaching practices and their PCK for NOS: (1) prerequisite knowledge and beliefs are necessary to teach NOS, (2) there is a developmental progression of PCK for NOS from knowledge to application level, (3) teachers need some comfort in their NOS understanding to teach NOS, and (4) the higher integration of PCK components leads to successful NOS teaching practices. Implications for science teacher education and research are discussed. © 2015, Springer Science+Business Media Dordrecht Daha fazlası Daha az
Arslan H. | Garip A.K. | Taran S.
Makale | 2019 | Journal of Nanoparticle Research21 ( 6 ) , pp.575 - 612
In this study, the classical molecular dynamics simulations in canonical ensemble conditions (NVT) were used to investigate the dynamical properties of bimetallic Co–Au nanoalloy clusters with the interatomic interactions modeled by Gupta many-body potential. Global optimizations were performed using basin-hopping algorithm for all compositions of 147 atom Co–Au bimetallic clusters. A structure based on icosahedron was obtained for the majority of the compositions. Structural analysis results showed that lower surface and cohesive energy of Au atoms give rise to Au atoms on the surface sites preferably. The global minimum structures . . . were taken as the initial configurations for MD simulations. We obtained caloric curves and also Lindemann parameters to investigate melting transitions. In general, the melting temperatures were fluctuated around 675 K for Au-rich compositions and 750 K for Co-rich compositions. © 2019, Springer Nature B.V Daha fazlası Daha az
Makale | 1999 | Transition Metal Chemistry24 ( 1 ) , pp.77 - 80
Molybdenum and tungsten tetracarbonyl compounds of the cis-[M(CO)4L2] (M = Mo, L2 = apmi, appi, apmi-Ph, appi-2-OMe, apmi-1-Me-1-Ph, bpmi, bppi, bpmi-Ph, bppi-2-OMe, bpmi-1-Me-1-Ph, bpai, M = W, L2 = apmi, appi, appi-2-OMe, bppi, bppi-2-OMe)† type have been prepared and characterised by 1H n.m.r., i.r., FAB-MS spectroscopy and by microanalysis.
Mouton A. | Mortelliti A. | Grill A. | Sara M. | Kryštufek B. | Juškaitis R. | Latinne A.
Makale | 2017 | Conservation Genetics18 ( 1 ) , pp.181 - 196
Robust identification of species and significant evolutionary units (ESUs) is essential to implement appropriate conservation strategies for endangered species. However, definitions of species or ESUs are numerous and sometimes controversial, which might lead to biased conclusions, with serious consequences for the management of endangered species. The hazel dormouse, an arboreal rodent of conservation concern throughout Europe is an ideal model species to investigate the relevance of species identification for conservation purposes. This species is a member of the Gliridae family, which is protected in Europe and seriously threaten . . .ed in the northern part of its range. We assessed the extent of genetic subdivision in the hazel dormouse by sequencing one mitochondrial gene (cytb) and two nuclear genes (BFIBR, APOB) and genotyping 10 autosomal microsatellites. These data were analysed using a combination of phylogenetic analyses and species delimitation methods. Multilocus analyses revealed the presence of two genetically distinct lineages (approximately 11 % cytb genetic divergence, no nuclear alleles shared) for the hazel dormouse in Europe, which presumably diverged during the Late Miocene. The phylogenetic patterns suggests that Muscardinus avellanarius populations could be split into two cryptic species respectively distributed in western and central-eastern Europe and Anatolia. However, the comparison of several species definitions and methods estimated the number of species between 1 and 10. Our results revealed the difficulty in choosing and applying an appropriate criterion and markers to identify species and highlight the fact that consensus guidelines are essential for species delimitation in the future. In addition, this study contributes to a better knowledge about the evolutionary history of the species. © 2016, Springer Science+Business Media Dordrecht Daha fazlası Daha az
Arca D. | Citiroglu H.K. | Kutoglu H.S. | Mekik C. | Deguchi T.
Makale | 2017 | Natural Hazards87 ( 1 ) , pp.307 - 322
Kozlu is a mining town only 5 km away from the main city of Zonguldak and initially was not favored for settlement due to its rugged and hilly topography. However, along with hard coal production in large quantities throughout the years came the industrialization at its full speed with plenty job opportunities which then gave rise to intense population in the region where there were only a few sheds and slums just a century ago. Workers migrating to Kozlu in thousands needed dwellings to live in, but the law, so-called the Coal Basin Restrictions Law which came in effect in 1910, hindered the implementation of zoning plans. Planned . . .housing was not possible in the region not until the abolishment of the law in 1986. During these 76 years, the settlement in the area mostly by the mining and industry workers was carried out without proper zoning plans, usually on demand basis. Today because of this unplanned housing and harsh topography, the Kozlu settlement area (KSA) has a history of being attraction point for many natural and man-made disasters which can be summarized as are topography, geological and carstic structure, mining activities and mass movements. In this study, a settlement suitability map is produced for the study area using a geographic information system. The map produced is designated into four settlement suitability zones, namely suitable to settlement, slightly suitable to settlement, suitable to settlement with precautions and unsuitable to settlement. It clearly shows that 24.73% of the study area lies in suitable and slightly suitable to settlement areas while the bulky rest pertains to suitable to settlement with precautions and unsuitable to settlement. The latest studies show that the 37.5% of the buildings and houses in the KSA are situated on the lithologic units identified as hydrogeological permeable and semipermeable, 7.8% on carstic caverns and a hefty rate of 47.6% on the surfaces deformed by mining-induced subsidence. Therefore, it is needless to claim that the administrators of Kozlu should promptly develop a settlement plan for the welfare of the city. © 2017, Springer Science+Business Media Dordrecht Daha fazlası Daha az
Becek K. | Horwath A.B.
Makale | 2017 | Natural Hazards85 ( 2 ) , pp.1279 - 1290
Vegetation and tropical forests in particular have a central role in mitigating the effects of increasing levels of atmospheric CO 2 . Photosynthesis is the fundamental process during which CO 2 is taken up by plants and fixed into carbohydrates. The effect of temperature on the rate of photosynthesis in different plant species is directly related to degree-days (D-D) as well as the leaf area index (LAI). Throughout the dry season, the reduced net primary productivity is tightly correlated with increasing D-D, while the reduction in soil moisture leads to progressive canopy thinning, indicated by decreasing LAI. Forest degradation e . . .xacerbated by soil erosion and depletion of nutrients in response to high rainfall intensities during the rainy season further disturbs the ecological balance of the entire ecosystem, destabilising it beyond its natural resilience. Given this fact, ground-based evidence and remote sensing-based findings, we propose a climatically induced cascade of events leading to a gradual alteration of the tropical forest ecosystems on Borneo with a diminishing ability to absorb CO 2 and release O 2 . Such a feedback loop, which is primarily triggered by increases in temperature, has potentially dangerous outcome for tropical ecosystems and has already been observed in the north-western state of Brunei Darussalam. The island of Borneo as a whole seems to have reached a level of forest degradation that is beyond a point of no return. In the worst-case scenario, the next niche of stability may be a destruction of tropical forests and the loss of a major proportion of Earth’s biodiversity. Our aim is to stimulate further research on such occurrences and inspire the implementation of future preventative measures. © 2016, The Author(s) Daha fazlası Daha az
Gunel-Ozcan A. | Basar M.M. | Kısa U. | Ankaralı H.C.
Makale | 2009 | Molecular Biology Reports36 ( 7 ) , pp.1709 - 1714
The aim of this study was to screen infertile men for HFE H63D mutation in correlation with clinical characteristics of infertile men (sperm concentration, sperm motility, morphology, testicular volume, Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH) and total Testosterone levels) and find out if the HFE H63D mutation has an effect on male infertility. After excluding hormonal treatment, any scrotal pathology, having any systemic diseases such as diabetes mellitus, sickle cell anemia and microdeletions of the Y chromosome, a total of 148 infertile men with age range between 17 and 52-years-old (average age 29.6 ± 7.2) w . . .ere enrolled into the study. Our analysis indicates that the mean FSH levels are significantly higher (6.3 ± 4.6 mIU/ml, P = 0.03), whereas sperm motility is significantly lower (36.6 ± 28.1%, P = 0.01) in the infertile men with the HFE H63D mutation compared with subjects lacking this mutation. Comparison of allele frequencies of the infertile men with Ts < 50% versus the infertile men with Ts > 50% revealed a significant difference as expected (P = 0.001, OR = 0.14, %95 CI = 0.04-0.44). Comparison of allele frequencies of infertile men with abnormal sperm motility versus infertile men with normal sperm motility revealed a highly significant difference (P = 0.005, OR = 3.11, %95 CI = 1.41-6.86). Thus, the HFE H63D mutation seems to be an important risk factor for impaired sperm motility and is clinically associated with male infertility. © 2008 Springer Science+Business Media B.V Daha fazlası Daha az
Makale | 2016 | Journal of Science Teacher Education27 ( 5 ) , pp.495 - 532
The purpose of this case study is to delve into the complexities of how preservice science teachers’ science teaching orientations, viewed as an interrelated set of beliefs, interact with the other components of pedagogical content knowledge (PCK). Eight preservice science teachers participated in the study. Qualitative data were collected in the form of content representation, responses to an open-ended instrument, and semi-structured interviews. Preservice teachers’ orientation and PCK were analyzed deductively. Constant comparison analysis of how their orientation interacted with other PCK components revealed three major themes: . . .(1) one’s purpose for science teaching determines the PCK component(s) with which it interacts, (2) a teacher’s beliefs about the nature of science do not directly interact with his/her PCK, unless those beliefs relate directly to the purposes of teaching science, and (3) beliefs about science teaching and learning mostly interact with knowledge of instructional strategies. Implications for science teacher education and research are discussed. © 2016, The Association for Science Teacher Education, USA Daha fazlası Daha az
Gurelik G. | Safak N. | Koksal M. | Bilgihan K. | Hasanreisoglu B.
Makale | 1999 | International Ophthalmology23 ( 3 ) , pp.131 - 135
Purpose: To assess acute corneal decompensation after silicone oil removal in some aphakic eyes with clear corneas whose anterior chambers were completely filled with silicone oil for a considerable period of time. Methods: Eight eyes of 8 patients who underwent vitrectomy and intraocular silicone oil injection were studied. All the eyes were aphakic and anterior chambers were completely filled with silicone oil. In all eyes, corneas were clear and no corneal finding indicating keratopathy was detected by slit-lamp microscopy before silicone oil removal. The mean silicone oil removal time was 4 months (range 2-7 months). A specular . . .microscope was used for the evaluation of corneal endothelial changes and corneal pachometry was performed to observe corneal changes before and after the silicone oil removal in 5 eyes besides slit-lamp microscopy. The follow up period after silicone oil removal was 2-12 months (mean 6 months). Results: In all eyes severe corneal stromal edema and clouding was detected in the first day following silicone oil removal. Increased corneal thickness was seen in all eyes. Decreased (at or below critical levels) corneal cell density was detected by specular microscopy before and after silicone oil removal. No significant improvement was observed during the follow up period. Conclusion: Eyes whose anterior chambers completely filled with silicone oil could be evaluated as clear corneas by slit lamp microscopy despite severe endothelial damage. We recommend that eyes with silicone oil in the anterior chambers should be monitored by a combination of slit-lamp microscopic examination and specular microscopy to determine the relative corneal endothelial tolerance to the silicone oil and endothelial damage. Early removal of the silicone oil can be considered when the retinal adhesion allows Daha fazlası Daha az
Konferans nesnesi | 2004 | Journal of Intelligent Manufacturing15 ( 4 ) , pp.463 - 470
Process planning is a decision-making process. Decisions on machining operations for a particular feature have to be made on various independent conditions such as which operation should be performed with which tools and under what cutting parameters. An integrated knowledge-based CAPP system called ProPlanner has been developed. The system has five modules namely information acquisition, feature recognition, machining operation planning and tool selection, set-up planning, and operation sequencing. Most process-planning systems do not produce alternative process plans. Usually, a fixed sequence created by a process plan is not nece . . .ssarily the best possible sequence, Therefore, the aim should be to generate all possible operation sequences and use some optimality criteria to obtain the best sequence for the given operating environment. This paper presents an efficient heuristic algorithm, belongs to the system's operation sequencing module, for finding near-optimal operation sequences from all available process plans in a machining set-up. The costs of the various machining schemes are calculated and the machining scheme with the lowest cost is chosen. All feasible cutting tools are identified for each particular feature and the corresponding machining operations. This process is repeated for all the features in the machining set-up. All possible feature sequence combinations allowed by the current feature constraints are then generated. Appropriate cutting tools are identified and assigned to different operations. The feature sequence with the smallest number of tool changes is adopted Daha fazlası Daha az