Pengaruh Tenure, Rotasi Dan Spesialisasi Kantor Akuntan Publik (KAP) Terhadap Kualitas Audit: Perbandingan Sebelum Dan Sesudah Regulasi Rotasi KAP Di Indonesia

Indonesia is a country that not only applied the rule of audit partner rotation, but also audit firm rotation with aim to improve the audit quality. This research tries to investigate the impact of audit firm audit rotation and audit tenure to the audit quality. The audit quality is measured by four earning quality (predictive value, timeliness, representational faithfulness and neutrality perspective). The sample data are the public listed companies from period before the regulation (1999-2001) to period after the regulation (2004-2008). This research finds that in the pre-regulation period, generally there is no impact of audit firm tenure to audit quality. In the after regulation period, audit firm tenure has convex relationship with audit quality from neutrality and timeliness perspectives with minimum point at 10 and 8.3 years (decrease for 10 years and 8.3 years and then increase). As the decrease period is quite long, we can conclude that the relationship between audit firm tenure and audit quality is negative. This research also found that generally no impact of audit rotation on audit quality, but 2 from 8 regression found that audit rotation decrease the audit quality in the pre and after regulation period. Specializations have positive impact to audit quality. Mandatory audit firm rotation may not be the most efficient way to enhance audit quality

Effect of electronic doping and traps on carrier dynamics in tin halide perovskites

Tin halide perovskites have recently emerged as promising materials for low band gap solar cells. Much effort has been invested on controlling the limiting factors responsible for poor device efficiencies, namely self-p-doping and tin oxidation. Both phenomena are related to the presence of defects; however, full understanding of their implications in the optoelectronic properties of the material is still missing. We provide a comprehensive picture of the competing radiative and non-radiative recombination processes in tin-based perovskite thin films to establish the interplay between doping and trapping by combining photoluminescence measurements with trapped-carrier dynamic simulations and first-principles calculations. We show that pristine Sn perovskites, i.e. sample processed with commercially available SnI2 used as received, exhibit extremely high radiative efficiency due to electronic doping which boosts the radiative band-to-band recombination. Contrarily, thin films where Sn4+ species are intentionally introduced show drastically reduced radiative lifetime and efficiency due to a dominance of Auger recombination at all excitation densities when the material is highly doped. The introduction of SnF2 reduces the doping and passivates Sn4+ trap states but conversely introduces additional non-radiative decay channels in the bulk that fundamentally limit the radiative efficiency. Overall, we provide a qualitative model that takes into account different types of traps present in tin-perovskite thin films and show how doping and defects can affect the optoelectronic properties

Erythrocytosis in a patient with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) can be accompanied by compensatory secondary erythrocytosis. However, the exact prevalence of secondary erythrocytosis in COPD is unknown. Although diagnostic criteria for polycythemia vera versus secondary erythrocytosis are mutually exclusive, we describe here the coexistence of polycythemia vera and COPD in the same patient

How Photogenerated I2 Induces I-Rich Phase Formation in Lead Mixed Halide Perovskites

Bandgap tunability of lead mixed halide perovskites (LMHPs) is a crucial characteristic for versatile optoelectronic applications. Nevertheless, LMHPs show the formation of iodide-rich (I-rich) phase under illumination, which destabilizes the semiconductor bandgap and impedes their exploitation. Here, it is shown that how I2 , photogenerated upon charge carrier trapping at iodine interstitials in LMHPs, can promote the formation of I-rich phase. I2 can react with bromide (Br- ) in the perovskite to form a trihalide ion I2 Br- (Iδ- -Iδ+ -Brδ- ), whose negatively charged iodide (Iδ- ) can further exchange with another lattice Br- to form the I-rich phase. Importantly, it is observed that the effectiveness of the process is dependent on the overall stability of the crystalline perovskite structure. Therefore, the bandgap instability in LMHPs is governed by two factors, i.e., the density of native defects leading to I2 production and the Br- binding strength within the crystalline unit. Eventually, this study provides rules for the design of chemical composition in LMHPs to reach their full potential for optoelectronic devices