Does trading by small investors improve or deteriorate price efficiency?

In this study, we investigate the effect of minimum trade unit (MTU) reductions on the Korea Exchange (KRX) on price efficiency. The KRX switched its MTU from 10 shares to one share for high-price stocks twice, once in December 2004 and once in July 2006. The MTU changes were intended to attract small individual investors to the markets for high-price stocks. The MTU reductions on the KRX are different from previous cases of MTU reductions in other markets in that the KRX MTU reductions are not chosen by firms but are mandated by the exchange. Using these rare events, we examine whether the reductions in MTU and ensuing small investor participation enhance or deteriorate price efficiency. We examine three variables as indicators of price efficiency: return volatility, residual volatility, and the half-life of return volatility shock estimated from a generalized autoregressive conditional heteroskedasticity (GARCH) model. We find evidence of improved price efficiency from the 2004 event. For the 2004 sample, both return variance and residual return variance declined significantly after the MTU reduction. We also find evidence of reduction, albeit weak, in the half-life of volatility shock for the same sample. Meanwhile, for the 2006 sample, we do not find any changes in return variance or residual variance, nor do we find any evidence of change in the half-life of volatility shock. The difference in the patterns of changes in variables between the 2004 and 2006 events appears to be attributable to differences in the price levels of the stocks that were affected by the MTU changes and, consequently, a difference in reactions by small investors

Approximation of circular arcs by Bézier curves

AbstractFor the circular arc of angle 0<α<π we present the explicit form of the best GC3 quartic approximation and the best GC2 quartic approximations of various types, and give the explicit form of the Hausdorff distance between the circular arc and the approximate Bézier curves for each case. We also show the existence of the GC4 quintic approximations to the arc, and find the explicit form of the best GC3 quintic approximation in certain constraints and their distances from the arc. All approximations we construct in this paper have the optimal order of approximation, twice of the degree of approximate Bézier curves

The UDP-Glycosyltransferase Family in Drosophila melanogaster: Nomenclature Update, Gene Expression and Phylogenetic Analysis.

UDP-glycosyltransferases (UGTs) are important conjugation enzymes found in all kingdoms of life, catalyzing a sugar conjugation with small lipophilic compounds and playing a crucial role in detoxification and homeostasis. The UGT gene family is defined by a signature motif in the C-terminal domain where the uridine diphosphate (UDP)-sugar donor binds. UGTs have been identified in a number of insect genomes over the last decade and much progress has been achieved in characterizing their expression patterns and molecular functions. Here, we present an update of the complete repertoire of UGT genes in Drosophila melanogaster and provide a brief overview of the latest research in this model insect. A total of 35 UGT genes are found in the D. melanogaster genome, localized to chromosomes 2 and 3 with a high degree of gene duplications on the chromosome arm 3R. All D. melanogaster UGT genes have now been named in FlyBase according to the unified UGT nomenclature guidelines. A phylogenetic analysis of UGT genes shows lineage-specific gene duplications. Analysis of anatomical and induced gene expression patterns demonstrate that some UGT genes are differentially expressed in various tissues or after environmental treatments. Extended searches of UGT orthologs from 18 additional Drosophila species reveal a diversity of UGT gene numbers and composition. The roles of Drosophila UGTs identified to date are briefly reviewed, and include xenobiotic metabolism, nicotine resistance, olfaction, cold tolerance, sclerotization, pigmentation, and immunity. Together, the updated genomic information and research overview provided herein will aid further research in this developing field

Ethnic differences in craniofacial and upper spine morphology in children with skeletal Class II malocclusion

OBJECTIVES: To analyze differences in upper cervical spine and craniofacial morphology, including posterior cranial fossa and growth prediction signs, between Danish and South Korean pre-orthodontic skeletal Class II children and to analyze associations between upper cervical spine morphology and craniofacial characteristics. MATERIALS AND METHODS: One hundred forty-six skeletal Class II children—93 Danes (54 boys and 39 girls, mean age 12.2 years) and 53 Koreans (27 boys and 26 girls, mean age 10.8 years)—were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender. RESULTS: Significant differences between the ethnic groups were found in the sagittal and vertical craniofacial dimensions (P < .001), mandibular shape (P < .01), dental relationship (P < .01), posterior cranial fossa (P < .05), and growth prediction signs (P < .001). No significant differences were found in upper spine morphology and Atlas dimensions between the groups. Upper spine morphology/dimensions were significantly associated with the cranial base angle (P < .01), sagittal craniofacial dimensions (P < .001), posterior cranial fossa (P < .001), and growth prediction signs (P < .05). CONCLUSIONS: Upper spine morphology/dimensions may be valuable as predictive factors in treatment planning for growing Class II children

Dual additives (lithium nitrate, lithium difluoro(bisoxalato)phosphate) to improve the electrochemical performance of Ni-rich cathode coupled with ultra-thin lithium metal anode

Department of Energy Engineering (Battery Science and Technology)Ni-rich layered oxide cathode (Ni> 80%) and lithium metal anode are strong candidates for high energy density batteries. However, the commercialization is limited due to the morphological instability of the Ni-rich cathode, low coulombic efficiency of lithium metal, and vertical growth of dendrites. Herein, we minimize the distance between the cathode and the anode to increase limit current density and add a dual additive to form a stable solid electrolyte interphase (SEI) layer on the anode and cathode surface. Concentrated ether-based electrolytes containing lithium nitrate (LiNO3) and lithium difluoro (bisoxalato) phosphate (LiDFBP) improves the capacity retention (80%) in a 20 ??m Li|LiNi0.8Co0.1Mn0.1O2 full cell, with a high Coulombic efficiency of 99.5% after 245 cycles at 0.9 C rate. This paper, which improves the battery performance through optimization of cell structure (distance between electrodes) and stabilization of the interface, is expected to help in various lithium metal battery research in the future.clos

ACTRA - A Case Study for Threat Information Sharing

This paper provides a case study for information sharing within a public/private not-for-profit partnership organization called ACTRA – Arizona Cyber Threat Response Alliance, Inc.. This initiative is comprised of public and private entities with government agencies as invited guests aligned around the goal of improved response to cyber security events. Technical, political, legal and organizational issues arise when multiple parties attempt to exchange information in a formal setting. Benefits and specific solutions developed are discussed. The study concludes with several areas for future improvement and investigation as well as recommendations for newly forming sharing groups