Analisis Pergerakan Indeks Harga Saham Gabungan (IHSG) Sebelum Dan Sesudah Pandemi Covid

The research is aimed at analyzing the movement of the Composite Stock Price Index (IHSG) before and after the COVID-19 pandemic March 2019-February period. The data used is the Composite Stock Price Index (IHSG) in Indonesia published by the Indonesia Stock Exchange (BEI). The research method used is quantitative with the type of research is an Event Study, with a Paired T-Test model. The result of this research showa that COVID-19 has a significant effect on the Composite Stock Price Index (IHSG) on the Indonesia Stock Exchange (BEI) for the period March 2019-February 2021

Pengaruh Metode Chain Writing terhadap Keterampilan Menulis Siswa Kelas V Sekolah Dasar

This study aimed to find out the effect of the implementation of the Chain Writing method on writing skills of grade V SDN Cisasah in learning to developing main ideas. This was a quantitative research with quasi experimental design. The basic consideration for using this design was that learning takes place naturally and the results obtained could be used to measure the effect of a treatment in the characteristics of the subject. The subject of this study were students grade V who came from two groups of students, namely the experimental group (implementing the Chain Writing method) and the control group. The data were collected through test technique divided two part, namely pretest and. The analysis technique this study was t-test. Based on this research showed that: (1) there are differences in the ability to writing skills to develop main ideas between students from experimental group with control group as evidence by the Sig. (2 tailed) is 0.00<0.05; and (2) there is an effect of implementing Chain Writing method for improving writing skills to developing the main ideas. Based on the mean value of the posttest results showed the experimental group is greater than the control group (83.70>57.90)Penelitian ini bertujuan untuk mengetahui pengaruh penerapan metode Chain Writing terhadap keterampilan menulis kelas V SD Negeri Cisasah dalam pembelajaran mengembangkan ide pokok. Jenis penelitian ini adalah kuantitatif dengan quasi experimental design. Dasar pertimbangan menggunakan desain ini adalah pembelajaran berlangsung secara alami sehingga hasil yang diperoleh dapat digunakan untuk mengukur pengaruh suatu perlakuan terhadap karakteristik subjek yang diteliti. Subjek penelitian ini adalah siswa kelas V SD yang berasal dari dua kelompok siswa, yaitu kelompok eksperimen (mengimplementasikan metode Chain Writing) dan kontrol. Pengumpulan data menggunakan teknik tes yang terbagi ke dalam dua bagian, yaitu pretest dan posttest keterampilan menulis mengembangkan ide pokok. Teknik analisis data penelitian ini menggunakan uji-t. Berdasarkan hasil penelitian diketahui bahwa: (1) terdapat perbedaan kemampuan menulis mengembangkan ide pokok antara siswa dari kelas eksperimen dengan kelas kontrol yang dibuktikan dari nilai Sig. (2-tailed) adalah 0.00<0.05; dan (2) terdapat pengaruh penggunaan metode Chain Writing dalam meningkatkan kemampuan menulis mengembangkan ide pokok siswa kelas V di SDN Cisasah. Hasil ini dibuktikan dari nilai rata-rata hasil posttest kelompok eksperimen lebih besar dibandingkan hasil posttest kelompok kontrol (83.70 > 57.90)

Causality between exchange rates and stock prices: evidence from Malaysia and Thailand

This study analyses the causal relationship between exchange rates and stock prices for Thailand and Malaysia. By using daily data from 1993 to 2003, this study attempts to examine the relationship between exchange rates and stock prices in Thailand and Malaysia during pre and post financial crisis. The paper also investigates the long-run relationship between the above-mentioned variables using Johansen-Juselius (1990) cointegration test and short-run dynamic causal relationship by using Toda-Yamamoto (1995) procedure. Likewise, variance decompositions (VDCs) analysis is employed to improve the predictable portion of exchange rate (stock price) changes on the forecast error variance in stock prices (exchange rates). Data from Thailand demonstrates the results predicted by the portfolio balance approach: stock prices lead exchange rates in both pre-crisis and post-crisis periods; however, Malaysian findings support portfolio approach in post-crisis

The standard theory of economic behavior towards risk large risks versus small risks

This paper focuses on some of the major theories of economic behavior towards risks and its efficiency in explaining risk attitudes towards large risks and small risks alike. Risk attitude measures the willingness of a decision maker to undertake risks in return for perceived rewards, ranging from risk aversion, risk neutrality, to risk preference. Due to earlier research exposing the limitations of the expected utility theorem in plausibly explaining risk aversion over relatively smaller stakes, this paper has empirically explored the possibilities that may cause similar ambiguous explanations in such modest-scale risk aversion. The empirical examination of the expected utility theory generally lends further supportive evidence that only large risks are capable of explaining risk aversion, with small to moderate risks being incapable of explaining risk-aversive behavior. Many other risk theories remain to be explored, and it is hoped that variants of these risk models might eventually lead to a more comprehensive coverage of risk behavior over the spectrum of large to small risks

Poly(ethylene glycol)-block-poly(4-vinyl pyridine) as a versatile block copolymer to prepare nanoaggregates of superparamagnetic iron oxide nanoparticles

This work reports an efficient method for the preparation of aqueous dispersions of superparamagnetic iron oxide nanoparticles (SPIONs), involving the use of an amphiphilic block copolymer, poly(ethylene glycol)- block-poly(4-vinyl pyridine) (mPEG-b-P4VP). The iron oxide nanoparticles are easily and efficiently dispersed due to the strong direct interaction of the hydrophobic P4VP segments, through complexation with pyridine units of the copolymer. Well-defined block copolymers, having different compositions and molecular weights, were prepared by atom transfer radical polymerization (ATRP). The aqueous selfassembly behavior of each system has been compared based on the method of preparation. The results revealed that the addition of ionic species has a significant effect on the size and type of formed nanostructures, the magnitude of which is dependent on the block copolymers' molecular design. When similar self-assembly strategies were used in the presence of SPIONs, the same type of nanostructures was formed. The hybrid SPION nanoaggregates were investigated using NMR relaxometric techniques, whereby high r2/r1 relaxivity ratios were achieved, making these materials potentially efficient T2- weighted MRI contrast agents.This work was financially supported by Fundação para a Ciência e a Tecnologia (Portugal), project Nanohybrid (PTDC/EQU-EPR/ 114354/2009) and project PEst-C/SAU/LA0001/2011, by Rede Nacional de RMN (REDE/1517/RMN/2005) with the acquisition of the Bruker Avance III 400 MHz NMR spectrometer in Coimbra (FEDER) and by the EU COST TD1004 Action “Theragnostics Imaging and Therapy”. Nuno Rocha acknowledges FCT-MCTES for his postdoctoral scholarship (SFRH/BPD/86352/2012)