• School Mathematics
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• v.4 no.4
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• pp.581-599
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• 2002

This study investigated the factorization concept development level of 3rd grades in middle school, the success of factorization problem solving, and the completion of factorization analogy tasks and science concepts analogy tasks. This study's results are followings. 1. Based on Sfard' reification levels, we classified students' factorization concept development levels from level 0 to level 3. As the students' development level was high, they tended to succeed the factorization problems gradually. 2. Experiencing factorization tasks which made students arrange factorization expressions hating same characterization, students ' factorization problem solving was improved. And, as the students' development level was high, they tended to attend to internal structural relations in factorization analogy tasks. 3. Analogy in factorization wasn't interrelated with analogy in science concepts. It said that analogy depended on the knowledges with it.

• Knowledge Management Research
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• v.21 no.2
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• pp.59-75
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• 2020

In this paper, we investigate the influence of factors on the firm, industry, and country levels on the new product development performance (NPD) of manufacturing firms in advanced economies. The resource-based view, industrial organization theory and institutional theory have established that firm-, industry- and country-level factors are all relevant for the NPD of firms. However, little is known about the relative importance of factors at the three different levels across countries, as prior studies on firms' NPD have focused on specific countries and levels of analysis. Our analysis of survey data from 1,437 manufacturing firms in nine advanced OECD countries shows that while firm-level factors are generally better predictors of firms' innovativeness than either industry- or country-level factors, the results strongly differ across countries, indicating that the relative importance of antecedents of innovativeness is country-specific rather than universal.

• The Mathematical Education
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• v.51 no.2
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• pp.173-189
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• 2012

This study investigated elementary and secondary mathematics teachers' views on: (1) Requirements for good mathematics teaching (2) what professional development programs and supports are needed for these requirements. In particular, this study analyzed the common and difference between school levels and teaching experiences. For it, we developed questionnaire and the questionnaire was anonymously answered by one-hundred-five elementary and secondary mathematics teachers. We suggested implications related to professional development programs for mathematics teachers based on common and difference between school levels and teaching experiences.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.522-527
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• 2017

We determined the effects of atmospheric temperature ($10-30{\pm}2^{\circ}C$ in $5^{\circ}C$ increments) and carbon dioxide ($CO_2$) levels ($400{\pm}50ppm$, $540{\pm}50ppm$, and $940{\pm}50ppm$) on the infection of Solanum tuberosum cv. Chubaek by Potato leafroll virus (PLRV). Below $CO_2$ levels of $400{\pm}50ppm$, the PLRV infection rate and RNA content in plant tissues increased as the temperature increased to $20{\pm}2^{\circ}C$, but declined at higher temperatures. At high $CO_2$ levels ($940{\pm}50ppm$), more plants were infected by PLRV at $30{\pm}2^{\circ}C$ than at 20 or $25{\pm}2^{\circ}C$, whereas PLRV RNA content was unchanged in the $20-30{\pm}2^{\circ}C$ temperature range. The effects of atmospheric $CO_2$ concentration on the acquisition of PLRV by Myzus persicae and accumulation of PLRV RNA in plant tissues were investigated using a growth chamber at $20{\pm}2^{\circ}C$. The M. persicae PLRV RNA content slightly increased at elevated $CO_2$ levels ($940{\pm}50ppm$), but this increase was not statistically significant. Transmission rates of PLRV by Physalis floridana increased as $CO_2$ concentration increased. More PLRV RNA accumulated in potato plants maintained at 540 or $940{\pm}50ppm$ $CO_2$, than in plants maintained at $400{\pm}50ppm$. This is the first evidence of greater PLRV RNA accumulation and larger numbers of S. tuberosum plants infected by PLRV under conditions of combined high $CO_2$ levels ($940{\pm}50ppm$) and high temperature ($30{\pm}2^{\circ}C$).

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.873-880
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• 2008

This paper deals with the peer-to-peer data communication to connect each distributed levels of developed unmanned system according to the JAUS. The JAUS is to support the acquisition of unmanned system by providing a mechanism for reducing system life-cycle costs. Each of distributed levels of the JAUS protocol divides into a system, some of subsystems, nodes and components/instances, each of which may be independent or interdependence. We have to distribute each of the levels because high performance is supported in order to create several sub-processor computing data in one processor with high CPU speed performance. To complement such disadvantage, we must think the concept that a distributed processing agrees with separating each of levels from the JAUS protocol. Therefore, each of distributed independent levels send data to another level and then it has to be able to process the received data in other levels. So, peer-to-peer communication has to control a data flow of distributed levels. In this research, we explain each of levels of the JAUS and peer-to-peer communication structure among the levels using our developed unmanned ground vehicle.

• Development and Reproduction
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• v.9 no.1
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• pp.15-22
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• 2005

The objective of the present study was to investigate changes of sex steroid(testosterone: T and $estradiol-17{\beta}:\;E_2$), cortisol levels and gonadal development following $T_3$ treatment to protandrous black porgy, Acanthopagrus schlegeli. Exogenous $T_3$ was found to significantly stimulate the increase of T levels in plasma of black porgy after 60 days of treatment. However no effects of $T_3$ on $E_2$ levels and oocyte size were found. $T_3$ treatment resulted in stimulated spermatogenesis and testicular development in gonad and prolonged spermiation. Also, the levels of cortisol were significantly increased in the fish treated with $T_3$ as compared to control fish at 60 days. The results showed that exogenous $T_3$ had direct effect on the release of T and cortisol, thus $T_3$ seems to play, either directly or indirectly, an important role in the testis development of functional male black porgy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.388-394
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• 2020

This study was undertaken to evaluate and compare the status of animal welfare, environmental level, and sow behavior, by including two farmhouses with sow group housing but having different floor types, viz., litter floor and slat floor. Animal welfare level was evaluated for body and vulval wounds of sows. The environmental level was measured for a total of 4 months, assessing the concentrations of H2S, NH3 and CO2 inside the pig house, once a month. Results of this study indicate that the level of animal welfare, with respect to body and vulval wounds, was better in the concrete slat floor farmhouse (H) than in the litter floor farmhouse (K). Environmental levels obtained (in ppm) were: H2S (H, 1.0; K, 0.0), NH3 (H, 45.4; K, 1.3), and CO2 (H, 1102.3; K, 258.8), indicating higher levels in the H than in K farmhouse. Aggressive behavior was mainly encountered in the H farmhouse. These results indicate that the same group housing system, but with different flooring, results in changes pertaining to aggressive behavior and environmental levels. It is therefore necessary to study the behavior changes, welfare, and environmental levels while deliberating different floor types.

• Journal of the Korean housing association
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• v.9 no.1
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• pp.99-107
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• 1998

This study intends to analyze residential satisfaction and preference of residents of urban core area. The main findings of this study are follows: First, the residents show high satisfaction levels for accessibility and availability of various facilities. However, they express relatively low levels of satisfaction for safety and amenities. Second, the satisfaction levels of female, housewives, and higher income earners are higher than the rest of residents. Third, more than half of core residents still want to live in the core area. This result implies the possibilities of residential development in the core area.

• Molecules and Cells
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• v.41 no.2
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• pp.103-109
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• 2018

Calcium ions are involved in the regulation of diverse cellular processes. Fourteen genes encoding calcium binding proteins have been identified in Dictyostelium. CBP7, one of the 14 CBPs, is composed of 169 amino acids and contains four EF-hand motifs. Here, we investigated the roles of CBP7 in the development and cell migration of Dictyostelium cells and found that high levels of CBP7 exerted a negative effect on cells aggregation during development, possibly by inhibiting chemoattractant-directed cell migration. While cells lacking CBP7 exhibited normal development and chemotaxis similar that of wild-type cells, CBP7 overexpressing cells completely lost their chemotactic abilities to move toward increasing cAMP concentrations. This resulted in inhibition of cellular aggregation, a process required for forming multicellular organisms during development. Low levels of cytosolic free calcium were observed in CBP7 overexpressing cells, which was likely the underlying cause of their lack of chemotaxis. Our results demonstrate that CBP7 plays an important role in cell spreading and cell-substrate adhesion. cbp7 null cells showed decreased cell size and cell-substrate adhesion. The present study contributes to further understanding the role of calcium signaling in regulation of cell migration and development.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.319-331
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• 2021

Heat stress (HS) causes adverse impacts on pig production and health. A potential biomarker of HS is required to predict its occurrence and thereby better manage pigs under HS. Information about the saliva metabolome in heat-stressed pigs is limited. Therefore, this study was aimed to investigate the effects of acute HS on the saliva metabolome and identify metabolites that could be used as potential biomarkers. Growing pigs (n = 6, 3 boars, and 3 gilts) were raised in a thermal neutral (TN; 25℃) environment for a 5-d adaptation period (CON). After adaptation, the pigs were first exposed to HS (30℃; HS30) and then exposed to higher HS (33℃; HS33) for 24 h. Saliva was collected after adaptation, first HS, and second HS, respectively, for metabolomic analysis using 1H-nuclear magnetic resonance spectroscopy. Four metabolites had significantly variable importance in the projection (VIP > 1; p < 0.05) different levels in TN compared to HS groups from all genders (boars and gilts). However, sex-specific characteristics affected metabolites (glutamate and leucine) by showing the opposite results, indicating that HS was less severe in females than in males. A decrease in creatine levels in males and an increase in creatine phosphate levels in females would have contributed to a protective effect from protein degradation by muscle damage. The results showed that HS led to an alteration in metabolites related to energy and protein. Protection from muscle damage may be attributed to the alteration in protein-related metabolites. However, energy-related metabolites showed opposing results according to sex-specific characteristics, such as sex hormone levels and subcutaneous fat layer. This study had shown that saliva samples could be used as a noninvasive method to evaluate heat-stressed pigs. And the results in this study could be contributed to the development of a diagnostic tool as a noninvasive biomarker for managing heat-stressed pigs.