Planar Contact Structures with Binding Number Three

In this article, we find the complete list of all contact structures (up to isotopy) on closed three-manifolds which are supported by an open book decomposition having planar pages with three (but not less) boundary components. We distinguish them by computing their first Chern classes and three dimensional invariants (whenever possible). Among these contact structures we also distinguish tight ones from those which are overtwisted.Comment: 35 pages, 19 figures, 9 tables (published version

On the support genus of a contact structure

The algorithm given by Akbulut-Ozbagci constructs an explicit open book decomposition on a contact three-manifold described by a contact surgery on a link in the three-sphere. In this article, we will improve this algorithm by using Giroux's contact cell decomposition process. Our algorithm is more economical on choosing the supporting genus of the open book; in particular it gives a good upper bound for the recently defined ``minimal supporting genus invariant'' of contact structures.Comment: 20 pages, 13 figures, title shorthened, minor correction

Measuring the e-Learning Autonomy of Distance Education Students

Previous studies have provided evidence that learner autonomy is an important factor in academic achievement. However, few studies have investigated the autonomy of distance education students in e-learning environments. The purpose of this study is to evaluate the e-learning autonomy of distance education students who are responsible for their own learning. For this purpose, as the first step of the study, an e-learning autonomy scale was developed. Analyses of the validity and reliability of the scale were carried out with the participation of 1,152 distance education students from Anadolu University, Open Education System. The scale has an internal consistency coefficient of α = 0.952 and a single factorial model that explains 66.58% of the total variance. The scale was implemented with 3,293 students from 42 different programs. According to the findings, student autonomy in e-learning environments is directly proportional to level of ICT use but not affected by program or gender

An Upper Bound for Accuracy of Prediction Using GBLUP.

This study aims at characterizing the asymptotic behavior of genomic prediction R2 as the size of the reference population increases for common or rare QTL alleles through simulations. Haplotypes derived from whole-genome sequence of 85 Caucasian individuals from the 1,000 Genomes Project were used to simulate random mating in a population of 10,000 individuals for at least 100 generations to create the LD structure in humans for a large number of individuals. To reduce computational demands, only SNPs within a 0.1M region of each of the first 5 chromosomes were used in simulations, and therefore, the total genome length simulated was 0.5M. When the genome length is 30M, to get the same genomic prediction R2 as with a 0.5M genome would require a reference population 60 fold larger. Three scenarios were considered varying in minor allele frequency distributions of markers and QTL, for h2 = 0.8 resembling height in humans. Total number of markers was 4,200 and QTL were 70 for each scenario. In this study, we considered the prediction accuracy in terms of an estimability problem, and thereby provided an upper bound for reliability of prediction, and thus, for prediction R2. Genomic prediction methods GBLUP, BayesB and BayesC were compared. Our results imply that for human height variable selection methods BayesB and BayesC applied to a 30M genome have no advantage over GBLUP when the size of reference population was small (<6,000 individuals), but are superior as more individuals are included in the reference population. All methods become asymptotically equivalent in terms of prediction R2, which approaches genomic heritability when the size of the reference population reaches 480,000 individuals

Time Dependent Live-bed Scour Around Circular Piers under Flood Waves

The aim of this study is to investigate live-bed scour under unsteady flow. During the experiments, 16 different triangular hydrographs were generated. Circular piers with three different diameters were tested under these hydrographs. Uniform bed material of 1.63 mm diameter was used during the experiments. The effects of the peak flow rate, the duration of hydrographs and the pier diameter on scour were interpreted. It was observed that the dominant element of the scour was the flow rate during the rising limb and the sediment transport rate during the falling limb. Maximum scour depths took place near the peak flow and lower final scour depths occurred at the end of the hydrograph. Two empirical equations were derived to predict time dependent scour depth and maximum scour depth. Statistically significant determination coefficient values and scatter indices were obtained

Securitization and desecuritization of energy resources: insights from alsace-lorraine for Cyprus island

Energy resources since the industrial revolution have been paramount for both developing and developed countries. Therefore, the urgent need for and control over energy resources in order to have an advantage against rivalries have become a significant part of national security. From the late 18th century to early 20th century, coal and gasoline were major energy resources to make machines operational but they have been gradually replaced by the fossil fuels, oil and gas. While transformation is happening, dependency on energy resources in the fields ranging from housewarming to jet fuels dramatically increased. Having adequate energy resources, in this sense, provides industrially and economically strategic advantages for a country, so military or political struggles over energy resources have been a salient issue in international relations. This paper seeks to examine the struggle over energy resources under the light of Alsace-Lorraine case and to compare the results with the Cyprus case. In doing so, securitization studies facilitate theoretical ground on how energy resources are securitized, which leads to a country to take extreme cautions, including armed conflict and on how energy resources are de-securitized, which leads to changes in foreign policies from conflict to cooperatio

Evaluation of Plasticity Models Using Uniaxial Tensile Test

In this study, it is aimed to evaluate plasticity model prediction performance for plastic behavior of materials using a uniaxial tensile test. For this purpose, von Mises, Hill-48, Hill-93, Barlat-89 and Hu -2003 plasticity models are studied, and DC04, DP780, 6000 series aluminum alloy are used as materials. Tensile tests are performed with three directions (rolling, diagonal, transverse), and mechanical properties of materials are obtained. In addition, anisotropy coefficients of materials are calculated by uniaxial tensile tests. Validation of plasticity models is performed using obtained material parameters. Yield locus and yield stresses-anisotropy coefficients depends on directions are used in evaluation of plasticity models. As a result of this study, Hu-2003 showed the best modeling performance for all materials