Transmission Mechanisms of Executive Compensation to Cost of Equity Capital

Kanyarat (Lek) Sanoran 사람과세계경영학회 2022 Global Business and Finance Review Vol.27 No.4

Purpose: The nature of each component of executive compensation varies, resulting in variances in executive incentives and investor pricing. To examine whether there is a differential relation between executive compensation components and cost of equity capital, this study decomposes the effects of executive compensation components on the cost of equity capital into wealth alignment, contribution, time horizon, and equity incentive effects. Design/methodology/approach: The hypotheses on the impact of each transmission mechanism of executive compensation component are separately developed in this study. The regression analyses are based on a sample of 11,649 firm-year observations of the U.S. listed companies during 1998-2014. Findings: The findings support all hypotheses by showing a significant reduction in cost of equity capital for bonus plans, long-term performance plans, and shareholdings, but a significant increase in cost of equity capital for salary and stock option. Research limitations/implications: The conclusions of this study are based on an examination of publicly listed companies in the United States; the hypotheses can be tested in other countries with various business environments and cultures. Originality/value: This study is a first attempt to explain the transmission mechanisms of executive compensation components and cost of equity capital by presenting evidence in support of wealth alignment effect, contribution effect, time horizon effect, and equity incentive effect.

Evaluation of Environmental Factors to Determine the Distribution of Functional Feeding Groups of Benthic Macroinvertebrates Using an Artificial Neural Network

박영석,Sovan Lek,전태수,Piet F.M. Verdonschot 한국생태학회 2008 Journal of Ecology and Environment Vol.31 No.3

Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of different groups can change in response to disturbances that affect the food base of the system, thereby offering a means of assessing disruption of ecosystem functioning. In this study, we used benthic macroinvertebrate communities collected at 650 sites of 23 different water types in the province of Overijssel, The Netherlands. Physical and chemical environmental factors were measured at each sampling site. Each taxon was assigned to its corresponding FFG based on its food resources. A multilayer perceptron (MLP) using a backpropagation algorithm, a supervised artificial neural network, was applied to evaluate the influence of environmental variables to the FFGs of benthic macroinvertebrates through a sensitivity analysis. In the evaluation of input variables, the sensitivity analysis with partial derivatives demonstrates the relative importance of influential environmental variables on the FFG, showing that different variables influence the FFG in various ways. Collector-filterers and shredders were mainly influenced by Ca²+ and width of the streams, and scrapers were influenced mostly with Ca²+ and depth, and predators were by depth and pH. Ca²+ and depth displayed relatively high influence on all four FFGs, while some variables such as pH, %gravel, %silt, and %bank affected specific groups. This approach can help to characterize community structure and to ecologically assess target ecosystems. Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of different groups can change in response to disturbances that affect the food base of the system, thereby offering a means of assessing disruption of ecosystem functioning. In this study, we used benthic macroinvertebrate communities collected at 650 sites of 23 different water types in the province of Overijssel, The Netherlands. Physical and chemical environmental factors were measured at each sampling site. Each taxon was assigned to its corresponding FFG based on its food resources. A multilayer perceptron (MLP) using a backpropagation algorithm, a supervised artificial neural network, was applied to evaluate the influence of environmental variables to the FFGs of benthic macroinvertebrates through a sensitivity analysis. In the evaluation of input variables, the sensitivity analysis with partial derivatives demonstrates the relative importance of influential environmental variables on the FFG, showing that different variables influence the FFG in various ways. Collector-filterers and shredders were mainly influenced by Ca²+ and width of the streams, and scrapers were influenced mostly with Ca²+ and depth, and predators were by depth and pH. Ca²+ and depth displayed relatively high influence on all four FFGs, while some variables such as pH, %gravel, %silt, and %bank affected specific groups. This approach can help to characterize community structure and to ecologically assess target ecosystems.

Oxalic acid assisted synthesis of the photochromic tungsten trioxide nanostructure

Parnumart Choopool,Lek Sikong,Kalayanee Kooptarnond 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.12

The photochromic material, tungsten trioxide nanostructure has been successfully prepared by the simple precipitationmethod using nitric acid with the assistance of an oxalic acid. The effect of oxalic acid as the chelating agent on themorphologies, crystal structure, the optical properties and photochromic properties were investigated. The synthesizednanostructure characterized by X-ray diffractometer consisted of orthorhombic and hexagonal phase. The results fromscanning electron microscopy and transmission electron microscopy presented the flower-like shaped nanostructure formed bythe growth of many nanosheets. UV-vis spectrophotometer displayed the absorbance peak at lower than 550 nm. The band gapenergies of the products were decreased and the powder changed color from yellow to dark green after UV irradiation. Theproducts prepared with oxalic acid exhibited the highest photochromic effect due to the mixed phase of orthorhombic (81%)and hexagonal (19%) crystalline which having more defect concentration in its structure and the narrow band gap energy.

Temperature-programmed desorption study of NO reactions on rutile TiO₂(110)-1×1

Kim, Boseong,Dohná,lek, Zdenek,Szanyi, Já,nos,Kay, Bruce D.,Kim, Yu Kwon Elsevier 2016 Surface science Vol.652 No.-

<P><B>Abstract</B></P> <P>Systematic temperature-programmed desorption (TPD) studies of NO adsorption and reactions on rutile TiO<SUB>2</SUB>(110)-1×1 surface reveal several distinct reaction channels in a temperature range of 50–500K. NO readily reacts on TiO<SUB>2</SUB>(110) to form N<SUB>2</SUB>O, which desorbs between 50 and 200K (LT N<SUB>2</SUB>O channels), which leaves the TiO<SUB>2</SUB> surface populated with adsorbed oxygen atoms (O<SUB>a</SUB>) as a by-product of N<SUB>2</SUB>O formation. In addition, we observe simultaneous desorption peaks of NO and N<SUB>2</SUB>O at 270K (HT1 N<SUB>2</SUB>O) and 400K (HT2 N<SUB>2</SUB>O), respectively, both of which are attributed to reaction-limited processes. No N-derived reaction product desorbs from TiO<SUB>2</SUB>(110) surface above 500K or higher, while the surface may be populated with O<SUB>a</SUB>'s and oxidized products such as NO<SUB>2</SUB> and NO<SUB>3</SUB>. The adsorbate-free TiO<SUB>2</SUB> surface with oxygen vacancies can be regenerated by prolonged annealing at 850K or higher. Detailed analysis of the three N<SUB>2</SUB>O desorption yields reveals that the surface species for the HT channels are likely to be various forms of NO dimers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N<SUB>2</SUB>O desorption from NO/TiO<SUB>2</SUB> is enhanced in the presence of oxygen vacancies (V<SUB>O</SUB>'s). </LI> <LI> Overall N<SUB>2</SUB>O yield saturates above a threshold NO dose. </LI> <LI> N<SUB>2</SUB>O yields on <I>h</I>-(or <I>r</I>-) TiO<SUB>2</SUB> are about the same with changes in desorption channels. </LI> <LI> Stabilization of NO in the presence of hydroxyls enhances LT and HT2 N<SUB>2</SUB>O channels. </LI> <LI> Oxidation of NO into NO<SUB>2</SUB> and NO<SUB>3</SUB> decreases the N<SUB>2</SUB>O desorption yield. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Electronic and Magnetic Properties of Copper Tetraazaporphyrin Influenced by Oxygen - a First-Principles Study

이재일,Beata Bia lek 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

We present the results of the electronic structure calculations for a copper tetraazaporphyrin (CuTAP) model monolayer, both bare and interacting with oxygen. The results are compared with those obtained for copper phthalocyanine. We have found that the CuTAP ferromagnetic configuration is preferred over the paramagnetic one. The calculated value of the magnetic moment of the Cu atom in the CuTAP monolayer is 0.54 µB. It does not affect strongly the magnetic properties of the monolayer, in which all but pyrrole nitrogen atoms remain unpolarized. The presence of oxygen molecules in the vicinity of the metallic center of the CuTAP causes a decrease in the magnetic moment of Cu, but does not much influence the overall magnetic properties of the monolayer. However, it influences slightly the ground-state electronic structure of the monolayer, mainly due to the charge transfer between the tetraazaporphyrin ring and the O2 molecules.

Isolation and Analysis of Bioactive Constituents of Sour Cherry (Prunus cerasus) Seed Kernel: An Emerging Functional Food

Istvan Bak,Istvan Lekli,Bela Juhasz,Edit Varga,Balazs Varga,Rudolf Gesztelyi,Levente Szendrei,Arpad Tosaki 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.4

A plant-based diet reduces the risk for the development of several chronic diseases, such as ischemic heart disease or cancer due to natural compounds found in plants. Numerous cereals, berries, fruits, and vegetables, including sour cherry (Prunus cerasus), which is a favored fruit worldwide, contain biological active components. The antioxidant components of the sour cherry seed kernel have not been investigated until now. The aim of our study was to isolate and analyze the bioactive constituents of sour cherry seed kernel. We separated the oil fraction of the kernel; then the remaining solid fraction was dried, and the oil-free kernel extract was further analyzed. Our results show that sour cherry seed kernel oil contains vegetable oils including unsaturated fatty acids, oleic acids, α-tocopherol, tocotrienols, and tocopherol-like components. The components of the solid fraction include various bioactive structures such as polyphenols, flavonoids, vegetable acids, and pro- and anthocyanidins, which could have useful therapeutic effects in the prevention of various vascular diseases.

Photocatalytic activity enhancement of Dy-doped TiO2 nanoparticles hybrid with TiO2 (B) nanobelts under UV and fluorescence irradiation

Thida San Nwe,Lek Sikong,Rungrote Kokoo,Matthana Khangkhamano 한국물리학회 2020 Current Applied Physics Vol.20 No.2

The main drawbacks of anatase titanium dioxide (TiO2) nanoparticles for being used as a photocatalyst are due to the rapid charge recombination of the electron-hole pairs and the wide band gap energy, limiting its photocatalysis application. To enhance photocatalytic activity, structure modification was performed here. Heterogeneous nanostructure of Dy-doped TiO2 nanoparticles hybrid with Monoclinic TiO2 nanobelts (Dy/TNBs) was fabricated via hydrothermal method. Annealing temperature was varied to investigate its effect on phase composition and morphology of the as-prepared TiO2 catalyst. Phase composition and morphology were studied by XRD and SEM, respectively. The effect of amount of catalyst loaded on the degradation efficiency of methylene blue (MB) dye in aqueous solution under UV and fluorescence illumination was investigated. The results showed that pure monoclinic TiO2 nanobelts (TNBs) was achieved at 450 °C. Enhanced photocatalytic activity under both UV and fluorescence irradiation was found on Dy/TNB samples. The optimum Dy dosage providing the highest MB degradation rates under both irradiation sources was 0.1 mol%.

Ammonia Formation from NO Reaction with Surface Hydroxyls on Rutile TiO₂(110)-1 × 1

Kim, Boseong,Kay, Bruce D.,Dohná,lek, Zdenek,Kim, Yu Kwon American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.2

<P>The reaction of NO with the hydroxylated rutile TiO2(110)-1 x 1 surface (h-TiO2) was investigated as a function of NO coverage using temperature-programmed desorption. Our results show that NO reaction with h-TiO2 leads to formation of NH3, which is observed to desorb at similar to 400 K. Interestingly, the amount of NH3 produced depends nonlinearly on the dose of NO. The yield increases up to a saturation value of similar to 1.3 x 10 (13) NH3/cm(2) at a NO dose of 5 x 10(-13) NO/cm(2), but subsequently decreases at higher NO doses. Preadsorbed H2O is found to have a negligible effect on the NH3 desorption yield. Additionally, no NH3 is formed in the absence of surface hydroxyls (HObs) upon coadsorption of NO and (HO)-O-2 on a stoichiometric TiO2(110) (s-TiO2(110)). On the basis of these observations, we conclude that nitrogen from NO has a strong preference to react with HObs on the bridge-bonded oxygen rows (but not with H2O) to form NH3. The absolute NH3 yield is limited by competing reactions of HOb species with titanium-bound oxygen adatoms to form H2O. Our results provide new mechanistic insight about the interactions of NO with hydroxyl groups on TiO2(110).</P>

Histopathology Analysis of Benign Colorectal Diseases and Colorectal Cancer in Hatyai Hospital, Songkhla, Thailand

Kotepui, Manas,Piwkham, Duangjai,Songsri, Apiram,Charoenkijkajorn, Lek Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Background: Colorectal cancer (CRC) is a major cause of morbidity and mortality in the western world and also ranks as the fifth-leading malignancy and death in Thailand. This study aimed to provide a present outlook of colorectal diseases among Thai patients with special emphasis on CRC in Hatyai, Songkhla, southern Thailand. Materials and Methods: This retrospective study covered ten year data of CRC, benign colorectal tumors and non-colorectal tumors from the Department of Pathology in Hatyai Hospital, Songkhla, Thailand, between years 2003-2012. Incidence rates based on age, gender, ten year incidence trends, and distribution of histopathological characteristics of patients were calculated and demonstrated. Results: Out of 730 biopsies, 100 cases were benign colorectal tumors, 336 were CRC and 294 were non-colorectal tumors. Colorectal tumors (both benign and CRC) (60.1%) were more common than non-colorectal tumors (39.9%). CRC (77.1%) were more common than benign colorectal tumors (32.9%). Colorectal tumors were mainly found in patients aged over sixty whereas non-colorectal and benign colorectal tumors were found in those under sixty (P=0.01). sAmong CRC, adenocarcinoma contributed about 97.3% of all cases with well differentiated tumors being the most frequent (56.9%). Both benign colorectal tumors and CRC were more commonly found in males (63%) than females (37%). The incidence trend of CRC demonstrated increase from 2003-2012. Conclusions: The incidence of CRC increased in Hatyai from 2003-2012. CRC tends to be more common in people older than sixty, thus, screening programs, cost-effective analysis of treatment modalities, and treatment protocols for the elderly should be examined. Proper implementation of preventive measures such as changing lifestyle factors might enhance control of colorectal disease.

DGGE를 활용한 BAF 공정의 생물막 세균 군집 분석

김영화 ( Young-hwa Kim ),( Pongsak (lek) Noophan ),안영희 ( Yeong-hee Ahn ) 한국환경기술학회 2016 한국환경기술학회지 Vol.17 No.2

BAF(Biological aerated filter) 공정은 기존 활성슬러지 공법에 비해 비교적 소요부지가 작고 폐수처리 효율이 높은 장점이 있다. 보통 BAF반응기에는 미생물이 생물막을 형성할 수 있는 여재가 채워져 있다. 여재의 생물막 미생물은 이 공정의 처리효율에서 중요한 역할을 함에도 불구하고 잘 알려지지 않았다. 미생물에 대한 정보는 이 공정의 성능향상을 위한 전략개발에 필수적이다. 본 연구 에서는 PCR-DGGE기법으로 BAF공정으로 운영되는 폐수처리장의 무산소조와 호기조 내의 생물막 미생물을 분석하였다. 각 반응조의 여재로부터 DNA를 추출하여 16S rRNA 유전자 단편을 PCR로 증폭하였다. 증폭된 PCR산물로 DGGE를 실시한 결과 두 반응조 시료의 밴드 패턴은 물론이고 주요 밴드가 서로 다르게 나타나, 두 반응조 내의 미생물 군집조성과 우점종이 서로 다름을 알 수 있었다. 이는 각 반응조의 환경 조건이 군집조성과 우점종에 영향을 미친 것으로 사료된다. 무산소조의 우점 종들은 Cytophagia 강과 β-Proteobacteria 강에 속하는 것으로 나타났으며, 한편 호기조의 우점종들은α-Proteobacteria 강과 Nitrospira 강에 해당되는 것으로 나타났다. 향후 운전조건에 따라 반응조 내의 우점 미생물의 동적 변화를 조사하여 처리효율과의 상관관계를 연구하면 본 공정의 처리 효율을 향상시키는데 기여할 수 있을 것이다. Biological aerated filter(BAF) process requires less area for plants and shows higher efficiency of wastewater treatment than conventional activated sludge process. BAF usually employs reactor(s) filled with filter media that can accommodate biofilm microorganisms. Although the microorganisms play important roles in wastewater treatment by the process, information on the biofilm microorganisms is limited. The information is necessary to develop strategies to enhance performance of the process. PCR-DGGE technique was used in this study to analyze biofilm microorganisms in anoxic and aerobic tanks of a sewage treatment plant employing BAF process. Total DNA was extracted from the media sampled from the tanks and used to amplify 16S rRNA gene fragments. DGGE was performed using the fragments to investigate microbial community. Samples from the two tanks showed different DGGE-band patterns and major bands, which suggested anoxic and aerobic tanks had different microbial community and dominant bacteria. The difference in microbial community composition and dominant bacteria could be due to different environmental conditions in the tanks. Major bands detected in anoxic tank belonged to classes Cytophagia and β-Proteobacteria, whereas those in the aerobic one were affiliated with classes α-Proteobacteria and Nitrospira. Research on microbial dynamics under various operational conditions is warranted to enhance performance of BAF process.