Multiple magnetic phase transitions with different universality classes in bilayer La$$_{1.4}$$Sr$$_{1.6}$$Mn$$_{2}$$O$$_7$$ manganite

Here, we report three magnetic transitions at 101 K (T$$_{C1}$$ C 1 ), 246 K (T$$_{C2}$$ C 2 ) and 295 K (T$$_{C3}$$ C 3 ) in bilayer La$$_{1.4}$$ 1.4 Sr$$_{1.6}$$ 1.6 Mn$$_{2}$$ 2 O$$_7$$ 7 . The second order phase transitions have been identified at these transition points with the help of change in entropy analysis and modified Arrott plots (MAPs). The critical behavior around T$$_{C1}$$ C 1 , T$$_{C2}$$ C 2 and T$$_{C3}$$ C 3 have been studied by MAPs and Kouvel–Fisher method. Based on these analyses four magnetic phases are: (1) 2D Ising ferromagnetic (FM) below T$$_{C1}$$ C 1 ,(2) 2D Heisenberg canted antiferromagnetic (CAFM-I) and FM clusters in temperature range T$$_{C1}$$ C 1 < T < T$$_{C2}$$ C 2 , (3) 2D Heisenberg CAFM-II and FM clusters with non magnetically interacting planes in temperature range T$$_{C2}$$ C 2 < T < T$$_{C3}$$ C 3 and (4) paramagnetic for T > T$$_{C3}$$ C 3 .

NGHIÊN CỨU BIỂU HIỆN TỚI HẠN TRONG CÁC BĂNG HỢP KIM Fe88Co2Zr7B2Cu1

In this work, we investigated the critical behavior of Fe88Co2Zr7B2Cu1 alloy ribbons prepared using a single-roller melt-spinning method. X-ray diffraction analysis shows that the alloy is almost amorphous. This alloy undergoes a second-order ferromagnetic-paramagnetic (FM-PM) phase transition at room temperature (Curie temperature TC = 296 K). To investigate the nature of the FM-PM phase transition near the TC for the alloy, we performed a critical-exponent study. Based on modified Arrott plots, the Kouvel-Fisher method, and Widom’s scaling relation, a set of critical parameters were determined. The critical parameters are β = 0.545 ± 0.041 and γ = 1.109 ± 0.018 obtained from the modified Arrott plots; β = 0.547 ± 0.005 and γ = 1.105 ± 0.016 from the Kouvel-Fisher method, and d = 3.035 ± 0.059 from Widom’s scaling relation. These values are close to those expected for the mean-field model, revealing long-range FM interactions.

SYNTHESIS OF DIBENZO[cd, g]INDOLE

In this paper, a synthesis method is proposed and discussed for a compound not previously described – dibenzo [cd, g] indole. For the successful synthesis of the target compound we used the classical method based on well-known procedure of indoles obtaining according to Fisher method with some changes. Commercially available derivatives of anthracene were used as the starting compound since they already contain a ready-made system of three condensed aromatic rings and they reaction activity is rather high. The corresponding diazonium salt was obtained from 9-amino anthracene by reaction with ethyl nitrite. Attempts to obtain the diazonium salt by reaction the amine with inorganic nitrites in an acidic aqueous medium did not lead to a product with an acceptable yield. 9-Antryl hydrazine was prepared by reducing the diazonium salt under mild conditions. Reduction was carried out using sulfur dioxide in aqueous sodium hydrosulfite. Formaldehyde of 9-anthrylhydrazone was obtained from anthrylhydrazine after condensation with paraformaldehyde. The target product was obtained by intramolecular cyclization of hydrazone under the action of BF3 * Et2O under the condition of high dilution and low temperature. The physicochemical characteristics of all the obtained compounds are determined. Melting point was determined on a Stuart SMP-30 instrument. IR spectra were recorded on a Nicolet 380 FT-IR spectrometer in tablets with potassium bromide. NMR spectra were recorded on a Bruker DRX-400 spectrometer (400 MHz), Me4Si was used as a 1H standard, in CDCl3 as a solvent. Elemental analysis was performed on a EuroEA 3000 analyzer. Based on the data from the above analysis methods, it was concluded that the proposed structures correspond to the real ones. In addition, we can conclude that synthesized products are individual substances.

DISCRIMINANT ANALYSIS THROUGH FISHER METHOD ON STUDENT'S MATERIALS BUILDING IN SMP 1 BANDA ACEH

The study is done for determining how many students and how the percentage of students who have mastered the material geometry about prism and pyramid, and getting the discriminant function about the mastery of the material. The study population was the entire eighth grade students of SMP Kasih Banda Aceh while the sample were students of class VIII-1 and VIII-8 to 66 students. Based on the research that has been done using the fisher discriminant analysis method, 18,18% of students have mastered the material geometry and 81,82% of students have not mastered the material geometry. It means that from 66 students only 12 students were able to master the material geometry about well- prism and pyramid. The discriminant function that is formed is and .

Detection of data fabrication using statistical tools

Scientific misconduct potentially invalidates findings in many scientific fields. Improved detection of unethical practices like data fabrication is considered to deter such practices. In two studies, we investigated the diagnostic performance of various statistical methods to detect fabricated quantitative data from psychological research. In Study 1, we tested the validity of statistical methods to detect fabricated data at the study level using summary statistics. Using (arguably) genuine data from the Many Labs 1 project on the anchoring effect (k=36) and fabricated data for the same effect by our participants (k=39), we tested the validity of our newly proposed 'reversed Fisher method', variance analyses, and extreme effect sizes, and a combination of these three indicators using the original Fisher method. Results indicate that the variance analyses perform fairly well when the homogeneity of population variances is accounted for and that extreme effect sizes perform similarly well in distinguishing genuine from fabricated data. The performance of the 'reversed Fisher method' was poor and depended on the types of tests included. In Study 2, we tested the validity of statistical methods to detect fabricated data using raw data. Using (arguably) genuine data from the Many Labs 3 project on the classic Stroop task (k=21) and fabricated data for the same effect by our participants (k=28), we investigated the performance of digit analyses, variance analyses, multivariate associations, and extreme effect sizes, and a combination of these four methods using the original Fisher method. Results indicate that variance analyses, extreme effect sizes, and multivariate associations perform fairly well to excellent in detecting fabricated data using raw data, while digit analyses perform at chance levels. The two studies provide mixed results on how the use of random number generators affects the detection of data fabrication. Ultimately, we consider the variance analyses, effect sizes, and multivariate associations valuable tools to detect potential data anomalies in empirical (summary or raw) data. However, we argue against widespread (possible automatic) application of these tools, because some fabricated data may be irregular in one aspect but not in another. Considering how violations of the assumptions of fabrication detection methods may yield high false positive or false negative probabilities, we recommend comparing potentially fabricated data to genuine data on the same topic.

Analisis Diskriminan Pada Pengklasifikasian Berat Bayi Baru Lahir

Analisis diskriminan merupakan metode statistik untuk menguji perbedaan signifikansi antara dua kelompok yang dalam kasus ini antara berat bayi baru lahir secara normal dan abnormal. Metode fisher merupakan metode yang bertujuan untuk membentuk fungsi diskriminan dengan koefisiennya untuk menghasilkan hasil maksimal antar grup dan variasi grup. Berdasarkan kriteria WHO, berat bayi saat lahir dibagi dua yaitu rendah (≤2500gram) dan normal (≥2500gram). Dalam penelitian ini, hasil yang didapat bahwa fungsi diskriminan yang terbentuk: Berat bayi baru lahir = 0.017 usia ibu + 0.535 jumlah anak + 0.338 + 0.32 aborsi. Persentase determinasi dari fungsi diskriminan ialah 80.0% Discriminant analysis is a statistical method used to test for significant differences between the two groups in this case is normal and abnormal newborns weight. The fisher method is a method that aims to form a discriminant function with its coefficients that produce maximum results between groups and group variations. Based on WHO Criteria, infant weight at birth is divided into two, namely low birth weight (≤2500gram) and normal birth weight (≥2500gram). in the research results obtained that discriminant function that is formed: New Baby Weight Born= 0.017 Mother Age + 0.535 Number of Children+ 0.338 Parity + 0.32 Abortion. Percentage of discriminant function determination is 80.0%.

Preprint of Too good to be false: Nonsignificant results revisited

Due to its probabilistic nature, Null Hypothesis Significance Testing (NHST) is subject to decision errors. The concern for false positives has overshadowed the concern for false negatives in the recent debates in psychology. This is unwarranted, since reported statistically nonsignificant findings may just be 'too good to be false'. We examined evidence for false negatives in nonsignificant results in three different ways. We adapted the Fisher method to detect the presence of at least one false negative in a set of statistically nonsignificant results. Simulations show that the adapted Fisher method generally is a powerful method to detect false negatives. We examined evidence for false negatives in the psychology literature in three applications of the adapted Fisher method. These applications indicate that (i) the observed effect size distribution of nonsignificant effects exceeds the expected distribution assuming a null-effect, and approximately two out of three (66.7%) psychology articles reporting nonsignificant results contain evidence for at least one false negative, (ii) nonsignificant results on gender effects contain evidence of true nonzero effects, and (iii) the statistically nonsignificant replications from the Reproducibility Project Psychology (RPP) do not warrant conclusions about the absence or presence of true zero effects underlying these nonsignificant results. We conclude that false negatives deserve more attention in the current debate on statistical practices in psychology. Neglecting effects due to a lack of statistical power can lead to a waste of research resources and stifle the scientific discovery process.