A New Approach to Performance Control in Earnings Management Studies

Yoon, Kim and Woodruff(2013) 한국회계정보학회 2013 한국회계정보학회 학술대회발표집 Vol.2013 No.2

We propose a cash flow from operations (CFO) portfolio approach to performance control issue in earnings management studies, which was initiated Kothari et al.(2005). We argue that the CFO portfolio is less costly, and yet controls performance more properly and ensures more stable and consistent measures of discretionary accruals than the Kothari et al. approach. We address the issues of alternative models as well as estimation approaches to make the study more comprehensive. We carry out diverse analyses and tests and document some important findings. First, the new models proposed by Yoon et al.(2013) are superior to the Jones and modified Jones models. Second, the industry approach results in unsigned or inconsistent regression coefficients across different industries. Third, the CFO portfolio approach significantly outperforms the industry approach, indicating that the estimation approach is more important than the models. Fourth, there are significant differences in mean nondiscretionary and discretionary accruals between different models when the industry approach is used. However, the between-model differences disappear when the CFO portfolio approach is used. Fifth, the Jones models do not properly isolate discretionary accruals particularly when the industry approach is used. We find that the application of a better estimation approach is more important than the choice of models. Sixth, CFO levels and estimation approach matter in terms of type-1 errors. There are larger differences in the rejection rates between the estimation approaches than between the models. However, the rejection rates are mostly lower than the hypothesized rate for the middle CFO level firm-years. Seventh, there are risks of drawing wrong inferences when the ROA control approach is used. Eighth, we document that a significant proportion of negative CFO firms employ income-increasing earnings management strategy to avoid loss reporting, and that there are considerable number of big-bath firms particularly when their CFO level is very low. Lastly, discretionary accruals can be overestimated (underestimated) when CFO level is negative (positive) under the industry approach, indicating that use of the CFO control approach is more warranted.

Changes of Students’Understanding of the Nature of Science After Two and Half Years of Public Science Education in Ontario Canada

박혜란,Woodruff, Earl 경북대학교 과학교육연구소 2014 科學敎育硏究誌 Vol.38 No.1

A longitudinal study traced changes in students’ understanding of Nature Of science (NOS) through the public secondary science education in Ontario Canada. Although the concepts of NOS are complicated, and students' understandings are not easy to change, not many longitudinal studies have been done across the world. The current study tried to identify the changes of participating students' understandings of NOS for two and half years of public secondary science education in Ontario Canada. Pretest was administered using Views of Nature of Science (VNOS-C) when six participants graduated from a middle school of Toronto. Two and half years of secondary education, the posttest was carried out using the same instrument. After pre and posttest, probing interviews were performed. The analysis of the data was founded on the Standards and the conceptual framework for this study. The findings were that the initial views have little changed. Most examples and explanations the participants provided were from their science classes. Lab activities for confirming the existing laws and theories and observable photos in science textbooks made students regard the knowledge as a truth. Naturally, their knowledge has been expanded for 2 and 1/2 years, but this expansion of scientific knowledge led students toward Universalist views on science. On the other hand, when science was presented with a historical approach or was networked with other concepts, students acknowledged science and scientific knowledge had been induced from inferences as well as observations and experimental results. Based on the findings the authors of this research suggest that educating the knowledge of science should be historical and networked approaches rather than teaching the knowledge as concise and true statements of the nature.

Knife’s edge: Balancing immunogenicity and reactogenicity in mRNA vaccines

Lee Jisun,Woodruff Matthew C.,Kim Eui-Ho,Nam Jae-Hwan 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Since the discovery of messenger RNA (mRNA), there have been tremendous efforts to wield them in the development of therapeutics and vaccines. During the COVID-19 pandemic, two mRNA vaccines were developed and approved in record-breaking time, revolutionizing the vaccine development landscape. Although first-generation COVID-19 mRNA vaccines have demonstrated over 90% efficacy, alongside strong immunogenicity in humoral and cell-mediated immune responses, their durability has lagged compared to long-lived vaccines, such as the yellow fever vaccine. Although worldwide vaccination campaigns have saved lives estimated in the tens of millions, side effects, ranging from mild reactogenicity to rare severe diseases, have been reported. This review provides an overview and mechanistic insights into immune responses and adverse effects documented primarily for COVID-19 mRNA vaccines. Furthermore, we discuss the perspectives of this promising vaccine platform and the challenges in balancing immunogenicity and adverse effects.

Single Optical Port Access Holographic Particle Image Velocimetry

Cha, Dong-Jin,Woodruff, Steven D. 한밭대학교 생산기반기술연구소 2001 생산기반기술연구소 논문집 Vol.1 No.1

An optical system, which requires only a single optical window mounted on a test volume, is proposed for holographic particle image velocimetry (HPIV). The optical system is a derivative of the double-exposure, double-reference-beam, off-axis HPIV system, but the innovative idea behind the system is to use back scattered light from the particles as the object wave. A 45˚ beam splitter inserted in front of the window serves to admit the illumination beam and extract the back scattered light. This concept can be of great engineering interest because optical access is often limited to one window in practical devices. The preliminary results of the technique appear quite promising, with current studies aimed at defining the optical resolution capabilities.

Changes of Students`Understanding of the Nature of Science After Two and Half Years of Public Science Education in Ontario Canada

( Hye Ran Park ),( Earl1 Woodruff ) 경북대학교 과학교육연구소 2014 科學敎育硏究誌 Vol.38 No.1

A longitudinal study traced changes in students` understanding of Nature Of science (NOS) through the public secondary science education in Ontario Canada. Although the concepts of NOS are complicated, and students` understandings are not easy to change, not many longitudinal studies have been done across the world. The current study tried to identify the changes of participating students` understandings of NOS for two and half years of public secondary science education in Ontario Canada. Pretest was administered using Views of Nature of Science (VNOS-C) when six participants graduated from a middle school of Toronto. Two and half years of secondary education, the posttest was carried out using the same instrument. After pre and posttest, probing interviews were performed. The analysis of the data was founded on the Standards and the conceptual framework for this study. The findings were that the initial views have little changed. Most examples and explanations the participants provided were from their science classes. Lab activities for confirming the existing laws and theories and observable photos in science textbooks made students regard the knowledge as a truth. Naturally, their knowledge has been expanded for 2 and 1/2 years, but this expansion of scientific knowledge led students toward Universalist views on science. On the other hand, when science was presented with a historical approach or was networked with other concepts, students acknowledged science and scientific knowledge had been induced from inferences as well as observations and experimental results. Based on the findings the authors of this research suggest that educating the knowledge of science should be historical and networked approaches rather than teaching the knowledge as concise and true statements of the nature.

Antagonists of Both D1 and D2 Mammalian Dopamine Receptors Block the Effects of Dopamine on Helix aspersa Neurons

Kim, Young-Kee,Woodruff, Michael L. Korean Society for Biochemistry and Molecular Biol 1995 Journal of biochemistry and molecular biology Vol.28 No.3

Dopamine mediates inhibitory responses in Helix aspersa neurons from the right parietal lobe ("F-lobe") of the circumoesophageal ganglia. The effects appeared as a dose-dependent hyperpolarization of the plasma membrane and a decrease in the occurrence of spontaneous action potentials. The average hyperpolarization with 5 ${\mu}m$ dopamine was -12 mV (${\pm}1.5$mV, S.D., n=12). Dopamine also modulated the currents 'responsible for shaping the action potentials in these neurons. When dopamine was added and action potentials were triggered by an injection of current, the initial depolarization was slowed, the amplitude and the duration of action potentials were decreased, and the after-hyperpolarization was more pronounced. The amplitude and the duration of action potential were reduced about 15 mV and about 13% by 5 ${\mu}m$ dopamine, respectively. The effects of dopamine on the resting membrane potentials and the action potentials of Helix neurons were dose-dependent in the concentration range 0.1 ${\mu}m$ to 50 ${\mu}m$. In order to show 1) that the effects of dopamine were mediated by dopamine receptors rather than by direct action on ionic channels and 2) which type of dopamine receptor might be responsible for the various effects, we assayed the ability of mammalian dopamine receptor antagonists, SCH-23390 (antagonist of D1 receptor) and spiperone (antagonist of D2 receptor), to block the dopamine-dependent changes. The D1 and D2 antagonists partially inhibited the dopamine-dependent hyperpolarization and the decrease in action potential amplitude. They both completely blocked the decrease in action potential duration and the increase in action potential after-hyperpolarization. The dopamine-induced slowdown of the depolarization in the initial phase of the action potentials was less effected by SCH-23390 and spiperone. From the results we suggest 1) that Helix F-lobe neurons may have a single type of dopamine receptor that binds both SCH-23390 and spiperone and 2) that the dopamine receptor of Helix F-lobe neurons may be homologous with and primitive to the family of mammalian dopamine receptors.

Antagonists of Both D1 and D2 Mammalian Dopamine Receptors Block the Effects of Dopamine on Helix aspersa Neurons

Kim, Young Kee,Woodruff, Michael L 생화학분자생물학회 1977 BMB Reports Vol.28 No.3

Dopamine mediates inhibitory responses in Helix aspersa neurons from the right parietal lobe ($quot;F-lobe$quot;) of the circumoesophageal ganglia. The effects appeared as a dose-dependent hyperpolarization of the plasma membrane and a decrease in the occurrence of spontaneous action potentials. The average hyperpolarization with 5 hM dopamine was -12 mV ( 1.5 mV, S.D., n=12). Dopamine also modulated the currents responsible for shaping the action potentials in these neurons. When dopamine was added and action potentials were triggered by an injection of current, the initial depolarization was slowed, the amplitude and the duration of action potentials were decreased, and the after-hyperpolarization was more pronounced. The amplitude and the duration of action potential were reduced about 15 mV and about 13% by 5 μM dopamine, respectively. The effects of dopamine on the resting membrane potentials and the action potentials of Helix neurons were dose-dependent in the concentration range 0.1 μM to 50 μM. In order to show 1) that the effects of dopamine were mediated by dopamine receptors rather than by direct action on ionic channels and 2) which type of dopamine receptor might be responsible for the various effects, we assayed the ability of mammalian dopamine receptor antagonists, SCH-23390 (antagonist of D1 receptor) and spiperone (antagonist of D2 receptor), to block the dopamine-dependent changes. The D1 and D2 antagonists partially inhibited the dopamine-dependent hyperpolarization and the decrease in action potential amplitude. They both completely blocked the decrease in action potential duration and the increase in action potential after-hyperpolarization. The dopamine-induced slowdown of the depolarization in the initial phase of the action potentials was less effected by SCH-23390 and spiperone. From the results we suggest 1) that Helix F-lobe neurons may have a single type of dopamine receptor that binds both SCH-23390 and spiperone and 2) that the dopamine receptor of Helix F-lobe neurons may be homologous with and primitive to the family of mammalian dopamine receptors.

단 관측장 측정을 위한 홀로그래피 입자 화상 유속계

차동진,Steven D. Woodruff 한밭대학교 생산융합기술연구소 2001 생산융합기술연구소 논문집 Vol.1 No.1

Mastoid osteoma: A rare incidental finding in an orthodontic patient

Borissova, Ioanna B.,Venturin, Jaqueline S.,Claro-Woodruff, Wanda I.,Shintaku, Werner H. Korean Academy of Oral and Maxillofacial Radiology 2020 Imaging Science in Dentistry Vol.50 No.4

Mastoid osteomas of the temporal bone are rare, benign, and usually asymptomatic tumors. However, depending on their size and extension, mastoid osteomas may cause facial palsy, a sensation of ear fullness, pressure-related pain, hearing loss, recurrent external ear infections, and chronic discharge. The etiology of mastoid osteomas is still unknown, but congenital, infectious, and traumatic factors have been proposed. Surgical treatment may be performed with minimal postoperative morbidity. In this article, the authors report a case of a 48-year-old woman seeking orthodontic treatment with an unusual retroauricular protruding mass, including the diagnostic process and differential diagnosis. This case supports the essential role of cone-beam computed tomography to analyze and identify the lesion as a mastoid osteoma.

Implication of Oxygen Level on the regulation of follicle growth in cultured mice ovaries in vitro

노재숙 ( Jae Sook Roh ),Teresa K Woodruff 대한산부인과학회 2008 대한산부인과학회 학술대회 Vol.94 No.-