The ground state properties of the spin-1/2 transverse Ising chain with periodically varying bonds and fields

Using continued fractions we study the ground state properties of the spin-1/2 Ising chain in a transverse field with periodically varying interaction strengths and external fields. We consider in detail the chain having the period of modulation of interactions equals 2 and compare the results obtained with those corresponding to the spin-1/2 isotropic XY chain in a transverse field. In contrast to the behaviour of the transverse XY chain, the transverse Ising chain does not exhibit a step-like magnetization vs. field dependence caused by the alternation of bonds, its susceptibility exhibits a logarithmic singularity at the field determined by interaction strengths, and it is stable with respect to spin-Peierls dimerization.Comment: 11 pages, latex, 4 figure

Analisis Kompetensi Guru Sebagai Bagian Dari Pedagogical Content Knowledge Guru Dalam Menerapkan Pendekatan Saintifik Dalam Program Plpg

The purpose of this research is to analyze the competence of teachers as part of the teachers\u27 pedagogical content knowledge in applying scientific approach in Mathematics PLPG (in-service teacher education and professional training) program rayon 138 Yogyakarta, Indonesia, in 2014. The research method used is descriptive with quantitative approach. The subjects of the study consisted of 23 mathematics teachers including mathematics teachers of junior high school, high school and vocational school from Kebumen, Purworejo, and Magelang. Data was collected by filling in a questionnaire at the beginning and end of the training, observing microteaching activities, and documenting the learning material arranged by PLPG participants. Based on the analysis, it can be concluded that PLPG especially PLPG rayon 138 Yogyakarta, Indonesia, in 2014 gives benefits for the development of teachers\u27 PCK, especially in terms of teachers\u27 competence in applying scientific approach. Based on the analysis of learning materials arranged by the teachers and analysis of learning videos, it is known that the majority of the teachers have been able to construct a learning material using scientific approach and implement it properly

Analysis of Difficulty Understanding Student Mathematica by Using Online Learning Model

This research is based on the low understanding of students’ mathematics. One of the causes for the low understanding of students’ mathematics is a factor in the students themselves in the form of student difficulties in solving problems related to the material in the Differential Calculus course. The purpose of this study was to describe the difficulties of students’ mathematical understanding in solving problems in the Differential Calculus Course using the online learning model. This type of research uses a qualitative approach and is descriptive in nature. The subjects of this study were first semester students taking Differential Calculus courses in the Mathematics Education study program, Muhammadiyah University of Tapanuli Selatan, Academic Year 2020/2021. The instrument used in this study was an interview. The results showed that the difficulties of students’ mathematical understanding in solving problems in the Differential Calculus course using the online learning model were related to technical difficulties, adaptation difficulties and internal difficulties for each individual student. To overcome these difficulties, it is necessary to have a more varied strategy for using online learning media. Keywords: Online learning; mathematic; medi

The 16 November 2006 flank collapse of South-East Crater at Mount Etna, Italy: study of the deposit and hazard assessment

On 16 November 2006 a flank collapse affected the unstable Eastern slope of the South-East Crater 16 (SEC) of Mt. Etna. The collapse occurred during one of the paroxysmal events with sustained strombolian 17 activity that characterized the August-December 2006 eruption and was triggered by erosion of loose, 18 hydrothermally-altered material of the steep south-east sector of SEC from the outpour of lava. The collapse 19 produced a debris avalanche that involved both lithic and juvenile material and resulted in a deposit 20 emplaced on the Eastern flank of the volcano up to 1.2 km away from the source. The total volume of the 21 deposit was estimated to be in the order of 330,000-413,000 m3. The reconstruction of the collapse event 22 was simulated using TITAN2D, software designed to model granular avalanches and landslides. This 23 approach can be used to estimate areas that may be affected by similar collapse events in the future. The 24 area affected by the 16 November 2006 lateral collapse of SEC was a small portion of the Mt. Etna summit 25 area, but the fact that no one was killed or injured should be considered fortuitous. The summit and adjacent 26 areas of the volcano, in fact, are usually visited by many tourists who are not prepared to face this type of 27 danger. The 16 November 2006 collapse points to the need to be prepared for similar events through 28 scientific investigation (analysis of flank instability, numerical simulation of flows) and development of specific civil protection plans

Increased Thyroid Hormone Levels in Pesticide Sprayer at Agricultural Area

Pesticides used massively in the agricultural sector would cause many poisoning and serious health problems. Organophosphate pesticides have been identified as endocrine-disrupting chemicals. This study aimed to compare thyroid hormone levels between the sprayers chronically exposed to pesticides and the control respondents who had never been exposed to pesticides. This study was an analytical observational with a cross-sectional design. The total number of respondents was 150, 50 as sprayers and 100 as control respondents. The venous blood samples were examined using the Enzyme-Linked Immunosorbent Assay (ELISA). The findings significantly showed that the sprayer had a higher level of thyroid-stimulating hormone (TSH) (4.776 ± 1.1166), lower triiodothyronine (T3) (108.822 ± 18.810), and lower thyroxine (T4) (7.808 ± 1.067). Determinant factors among sprayers that significantly correlated to TSH levels was age (p-value = 0.006); work duration (p-value = 0.000); personal protection equipment (PPE) (p-value = 0.045); body position (p-value = 0.014); type of pesticides (p-value = 0.004), correlated with T3 levels was age (p-value = 0.037); body position (p-value = 0.045), correlated with T4 levels was age (p-value = 0.000); PPE (p-value = 0.045). It could be concluded that chronic organophosphate exposure would increase TSH and decrease T3 and T4

Development of the Couple Stress Relationships for the Power Law Fluid and the Solution of Flow in Ceramic Tape Casting Process

The absence of characteristic material length in the Navier-Stokes equations has led to the development of different couple stress theories. In the present study, for the first time, the relations of a couple stress theory are extended to power-law fluids. Moreover, considering the significance of the length scale in nano- and micromechanics, the relations of the extended theory were applied to Newtonian and power-law fluids in tape casting of ceramics. The obtained velocity was used to calculate the volumetric flow rate as well as the thickness of the ceramic tape. A comparison between the results of the Newtonian fluid and the analytical and experimental results indicated a close agreement between the present results and the results of other studies. Moreover, the tape thickness was obtained for different length scales (L) by numerically solving the velocity relations obtained for the non-Newtonian fluid. Also, the impact of casting speed on the tape thickness was shown for four power-law fluids assuming L=0.35

Retinal findings of COVID-19 patients using ocular coherence tomography angiography two to three months after infection: Ocular appearance recovered COVID-19 patient

Purpose: The aim of this study was to evaluate the ocular disorders in COVID-19 patients, two to three months after infection. Methods: In this cross-sectional, historically controlled study, fifty-one COVID-19 patients were compared with thirty-seven age, and gender-matched healthy individuals. After complete ophthalmological examination, all participants underwent peripapillary and macular optical coherence tomography, and optical coherence tomography angiography (OCTA) measurements (OptoVue Inc, Freemont, CA, USA). Results: The time between the initial onset of symptoms, and ophthalmologic examination was 63.31±15.21 (40�95 days). Ophthalmic examination of all the recovered COVID-19 patients was within normal range. None of the peripapillary and macular OCTA parameters were significantly different between the two groups with pairwise comparisons, but after adjusting for age, gender, axial length, and signal strength index (SSI), recovered COVID-19 eyes showed a significant increase in peripapillary retinal nerve fiber (RNFL) thickness, superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with healthy control eyes (p<= 0.05). Inner retinal thickness overall is higher in recovered COVID-19 eyes compared to healthy eyes after adjustment. Conclusion: Patients with moderate-intensity SARS-CoV-2 pneumonia had altered peripapillary and macular vessel density compared to healthy subjects. Further investigation is warranted to analyze the correlation of these changes with disease severity as well as evolution of these changes over time

Pembuatan dan Pemurnian Etanol Dari Nira Aren dengan Menggunakan Teknik Destilasi Refluks

Telah dilakukan pembuatan dan pemurnian etanol dari nira aren dengan menggunakan teknik destilasi refluks. Etanol didapatkan dari air nira pohon aren yang telah terfermentasi secara alamiah dan didestilasi menggunakan teknik refluks untuk memperoleh kemurnian 70-96% (v/v). Konsentrasi etanol dalam kaldu yang digunakan dalam pemanasan adalah 30% dengan volume total 7 L dalam ketel (boiler). Sebelum separasi dimulai dilakukan pengeringan (drying) pada kolom dan kondensor dengan tujuan untuk memisahkan sisa air yang terdapat didalamnya. Hasil menunjukan bahwa etanol kemurnian 70%, 85%, 90%, 95% dan 96% diperoleh pada proses pemanasan dengan suhu kolom atas 82, 81, 79.3, 78.3, dan 78.5 ºC.Ethanol was been prepared and purified by using a reflux distillation method. Ethanol was obtained from a sap water tapped of the palm tree (arenga pinnata) and then was distilled by a reflux separation technique. The ethanol concentration obtained a range of 70-90% (v/v), the concentration of yeasted liquor filled inside boiler was of 30% with a volume 7 L. Prior to a separation conducted the reflux colomn was dried by flowing a warm air aiming remove a remnant water from the packing materials. The result showed that the ethanol with the concentration of 70%, 85%, 90%, 95% and 96% were obtained by setting the column temperature at 82, 81, 79.3, 78.3, 78.5ºC