698 research outputs found

    Numerical Solution of Some Nonlinear Volterra Integral Equations of the First Kind

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    In this paper, the solving of a class of the nonlinear Volterra integral equations (NVIE) of the first kind is investigated. Here, we convert NVIE of the first kind to a linear equation of the second kind. Then we apply the operational Tau method to the problem and prove convergence of the presented method. Finally, some numerical examples are given to show the accuracy of the method

    Meningkatkan Hasil Belajar Fisika Menggunakan Strategi Question Student Have Berbantuan Animasi di SMP

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    This research aims to improve student learning outcomes using Question Student Have strategy with animation media on light reflection in class VIII of MTS Al-Islamiya Rahaudatul Peniti Luar. There are 27 students involved in the study of this classroom action research. Based on data analysis concluded that the used of Question Student Have strategies with animation media can improve student learning outcomes in light reflection. Before the research was conducted, the average of student learning outcomes reached KKM (Criteria Complete Minimal) of 65.5. The number of students who reached KKM were 10 people with a percentage of 36.7%. After being given the action I, the average result of learning was 66.67. The number of students who reached KKM were 17 people with a percentage of 63%. The percentage of students who reached KKM increased by 26.3%. After being given a second action, the average learning outcomes was 73.3. The number of students who reached KKM for 21 people with a percentage of 77.8%. The percentage of students who reached KKM increased by 14.8%

    Understanding complex magnetic order in disordered cobalt hydroxides through analysis of the local structure

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    In many ostensibly crystalline materials, unit-cell-based descriptions do not always capture the complete physics of the system due to disruption in long-range order. In the series of cobalt hydroxides studied here, Co(OH)2x_{2-x}(Cl)x_x(H2_2O)n_{n}, magnetic Bragg diffraction reveals a fully compensated N\'eel state, yet the materials show significant and open magnetization loops. A detailed analysis of the local structure defines the aperiodic arrangement of cobalt coordination polyhedra. Representation of the structure as a combination of distinct polyhedral motifs explains the existence of locally uncompensated moments and provides a quantitative agreement with bulk magnetic measurements and magnetic Bragg diffraction

    Magneto-elastic coupling and competing entropy changes in substituted CoMnSi metamagnets

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    We use neutron diffraction, magnetometry and low temperature heat capacity to probe giant magneto-elastic coupling in CoMnSi-based antiferromagnets and to establish the origin of the entropy change that occurs at the metamagnetic transition in such compounds. We find a large difference between the electronic density of states of the antiferromagnetic and high magnetisation states. The magnetic field-induced entropy change is composed of this contribution and a significant counteracting lattice component, deduced from the presence of negative magnetostriction. In calculating the electronic entropy change, we note the importance of using an accurate model of the electronic density of states, which here varies rapidly close to the Fermi energy.Comment: 11 pages, 9 figures. Figures 4 and 6 were updated in v2 of this preprint. In v3, figures 1 and 2 have been updated, while Table II and the abstract have been extended. In v4, Table I has updated with relevant neutron diffraction dat

    Evaluation of patient outcome and satisfaction after surgical treatment of adolescent idiopathic scoliosis using scoliosis research society-30

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    Background: Adolescent idiopathic scoliosis (AIS) may lead to physical and mental problems. It also can adversely affect patient satisfaction and the quality of life. In this study, we assessed the outcomes and satisfaction rate after surgical treatment of AIS using scoliosis research society-30 questionnaire (SRS-30). Methods: We enrolled 135 patients with AIS undergoing corrective surgery. Patients were followed for at least 2 years. We compared pre- and post-operative x-rays in terms of Cobb's angles and coronal balance. At the last visit, patients completed the SRS-30 questionnaire. We then assessed the correlation between radiographic measures, SRS-30 total score, and patient satisfaction. Results: Cobb's angle and coronal balance improved significantly after surgery (P<0.001). The scores of functional activity, pain, self-image/cosmesis, mental health, and satisfaction were 27±4.3, 26±2.5, 33±5.2, 23±3.5, and 13±1.8, respectively. The total SRS-30 score was 127±13. Radiographic measures showed significant positive correlation with satisfaction and SRS-30 total scores. There was also a positive correlation between satisfaction and self-image/cosmesis domain scores. Conclusions: The greater the radiographic angles were corrected the higher the SRS-30 total score and patient satisfaction were. It is intuitive that the appearance and cosmesis is of most important factor associated with patient satisfaction. © 2015 BY THE ARCHIVES OF BONE AND JOINT SURGERY

    Correlated Differential Privacy: Feature Selection in Machine Learning

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    © 2005-2012 IEEE. Privacy preserving in machine learning is a crucial issue in industry informatics since data used for training in industries usually contain sensitive information. Existing differentially private machine learning algorithms have not considered the impact of data correlation, which may lead to more privacy leakage than expected in industrial applications. For example, data collected for traffic monitoring may contain some correlated records due to temporal correlation or user correlation. To fill this gap, in this article, we propose a correlation reduction scheme with differentially private feature selection considering the issue of privacy loss when data have correlation in machine learning tasks. The proposed scheme involves five steps with the goal of managing the extent of data correlation, preserving the privacy, and supporting accuracy in the prediction results. In this way, the impact of data correlation is relieved with the proposed feature selection scheme, and moreover the privacy issue of data correlation in learning is guaranteed. The proposed method can be widely used in machine learning algorithms, which provide services in industrial areas. Experiments show that the proposed scheme can produce better prediction results with machine learning tasks and fewer mean square errors for data queries compared to existing schemes

    Electronic structure and magnetic properties of the spin-1/2 Heisenberg system CuSe2O5

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    A microscopic magnetic model for the spin-1/2 Heisenberg chain compound CuSe2O5 is developed based on the results of a joint experimental and theoretical study. Magnetic susceptibility and specific heat data give evidence for quasi-1D magnetism with leading antiferromagnetic (AFM) couplings and an AFM ordering temperature of 17 K. For microscopic insight, full-potential DFT calculations within the local density approximation (LDA) were performed. Using the resulting band structure, a consistent set of transfer integrals for an effective one-band tight-binding model was obtained. Electronic correlations were treated on a mean-field level starting from LDA (LSDA+U method) and on a model level (Hubbard model). In excellent agreement of experiment and theory, we find that only two couplings in CuSe2O5 are relevant: the nearest-neighbour intra-chain interaction of 165 K and a non-frustrated inter-chain coupling of 20 K. From a comparison with structurally related systems (Sr2Cu(PO4)2, Bi2CuO4), general implications for a magnetic ordering in presence of inter-chain frustration are made.Comment: 20 pages, 8 figures, 3 table

    Quantification of spatial subclonal interactions enhancing the invasive phenotype of pediatric glioma.

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    Diffuse midline gliomas (DMGs) are highly aggressive, incurable childhood brain tumors. They present a clinical challenge due to many factors, including heterogeneity and diffuse infiltration, complicating disease management. Recent studies have described the existence of subclonal populations that may co-operate to drive pro-tumorigenic processes such as cellular invasion. However, a precise quantification of subclonal interactions is lacking, a problem that extends to other cancers. In this study, we combine spatial computational modeling of cellular interactions during invasion with co-evolution experiments of clonally disassembled patient-derived DMG cells. We design a Bayesian inference framework to quantify spatial subclonal interactions between molecular and phenotypically distinct lineages with different patterns of invasion. We show how this approach could discriminate genuine interactions, where one clone enhanced the invasive phenotype of another, from those apparently only due to the complex dynamics of spatially restricted growth. This study provides a framework for the quantification of subclonal interactions in DMG

    Giant crystal-electric-field effect and complex magnetic behavior in single-crystalline CeRh3Si2

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    Single-crystalline CeRh3Si2 was investigated by means of x-ray diffraction, magnetic susceptibility, magnetization, electrical resistivity, and specific heat measurements carried out in wide temperature and magnetic field ranges. Moreover, the electronic structure of the compound was studied at room temperature by cerium core-level x-ray photoemission spectroscopy (XPS). The physical properties were analyzed in terms of crystalline electric field and compared with results of ab-initio band structure calculations performed within the density functional theory approach. The compound was found to crystallize in the orthorhombic unit cell of the ErRh3Si2 type (space group Imma -- No.74, Pearson symbol: oI24) with the lattice parameters: a = 7.1330(14) A, b = 9.7340(19) A, and c = 5.6040(11) A. Analysis of the magnetic and XPS data revealed the presence of well localized magnetic moments of trivalent cerium ions. All physical properties were found to be highly anisotropic over the whole temperature range studied, and influenced by exceptionally strong crystalline electric field with the overall splitting of the 4f1 ground multiplet exceeding 5700 K. Antiferromagnetic order of the cerium magnetic moments at TN = 4.70(1)K and their subsequent spin rearrangement at Tt = 4.48(1) K manifest themselves as distinct anomalies in the temperature characteristics of all investigated physical properties and exhibit complex evolution in an external magnetic field. A tentative magnetic B-T phase diagram, constructed for B parallel to the b-axis being the easy magnetization direction, shows very complex magnetic behavior of CeRh3Si2, similar to that recently reported for an isostructural compound CeIr3Si2. The electronic band structure calculations corroborated the antiferromagnetic ordering of the cerium magnetic moments and well reproduced the experimental XPS valence band spectrum.Comment: 32 pages, 12 figures, to appear in Physical Review
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