• Korean Journal of Cognitive Science
• /
• v.34 no.3
• /
• pp.181-196
• /
• 2023

Size, velocity, and time equivalence are mechanisms that allow us to perceive objects in three-dimensional space consistently, despite errors on the two-dimensional retinal image. These mechanisms work on common cues, suggesting that the perception of motion distance, motion speed, and motion time may share common processing. This can lead to the hypothesis that, despite the spatial nature of visual stimuli distorting temporal perception, the perception of motion speed and the perception of motion duration will tend to oppose each other, as observed for objects moving in the environment. To test this hypothesis, the present study measured perceived speed using Müller-Lyer illusion stimulus to determine the relationship between the time-perception consequences of motion stimuli observed in previous studies and the speed perception measured in the present study. Experiment 1 manipulated the perceived motion trajectory while controlling for the retinal motion trajectory, and Experiment 2 manipulated the retinal motion trajectory while controlling for the perceived motion trajectory. The result is that the speed of the inward stimulus, which is perceived to be shorter, is estimated to be higher than that of the outward stimulus, which is perceived to be longer than the actual distance traveled. Taken together with previous time perception findings, namely that time perception is expanded for outward stimuli and contracted for inward stimuli, this suggests that when the perceived trajectory of a stimulus manipulated by the Müller-Lyer illusion is controlled for, perceived speed decreases with increasing duration and increases with decreasing duration when the perceived distance of the stimulus is constant. This relationship suggests that the relationship between time and speed perceived by spatial cues corresponds to the properties of objects moving in the environment, i.e, an increase in time decreases speed and a decrease in time increases speed when distance remains the same.

• Korean Journal of Environmental Biology
• /
• v.41 no.3
• /
• pp.325-334
• /
• 2023

The invasive red swamp crayfish, Procambarus clarkii, is native to south-central United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.

• Pediatric Infection and Vaccine
• /
• v.31 no.1
• /
• pp.75-82
• /
• 2024

Purpose: As the coronavirus disease 2019 (COVID-19) pandemic ended, the number of patients with respiratory syncytial virus (RSV) pneumonia increased during the spring/summer of 2022. This study aimed to analyze the clinical features and antibiotic usage of children hospitalized for RSV pneumonia in a recently established general hospital in Sejong city. Methods: In this retrospective review, we included inpatients of the Pediatric Department of Chungnam National University Sejong Hospital diagnosed with RSV pneumonia between March 2022 and April 2023. Patients were divided into 2 groups: with and without antibiotic treatment. Demographic data, initial presentations, and clinical courses were reviewed. Results: A total of 116 patients with RSV pneumonia were hospitalized during this period, of which 102 were analyzed, excluding 14 with underlying diseases or who did not fall within the definition of pneumonia. The median age was 17 months. Diagnoses of bacterial infections (acute otitis media and sinusitis) were documented in 9.8% of cases. Intravenous (IV) antibiotics were administered in 46% of cases. The group receiving IV antibiotics showed higher inflammatory levels (C-reactive protein; CRP), more infiltration on initial chest X-rays, and longer fever duration. There was no difference in the length of hospitalization between the groups with and without IV antibiotics. Conclusions: This study showed a tendency for the attending physician to prescribe IV antibiotics to patients with longer fever duration, pulmonary infiltrations on the initial chest X-ray, and higher CRP levels. However, given the high rate of IV antibiotic usage compared to previous studies, care should be taken in antibiotic use.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.37 no.1
• /
• pp.67-76
• /
• 2024

In this paper, we present a DIP-MLS testing method that combines digital image processing with a rigid body-based MLS differencing approach to measure mechanical variables and analyze the impact of target location and image resolution. This method assesses the displacement of the target attached to the sample through digital image processing and allocates this displacement to the node displacement of the MLS differencing method, which solely employs nodes to calculate mechanical variables such as stress and strain of the studied object. We propose an effective method to measure the displacement of the target's center of gravity using digital image processing. The calculation of mechanical variables through the MLS differencing method, incorporating image-based target displacement, facilitates easy computation of mechanical variables at arbitrary positions without constraints from meshes or grids. This is achieved by acquiring the accurate displacement history of the test specimen and utilizing the displacement of tracking points with low rigidity. The developed testing method was validated by comparing the measurement results of the sensor with those of the DIP-MLS testing method in a three-point bending test of a rubber beam. Additionally, numerical analysis results simulated only by the MLS differencing method were compared, confirming that the developed method accurately reproduces the actual test and shows good agreement with numerical analysis results before significant deformation. Furthermore, we analyzed the effects of boundary points by applying 46 tracking points, including corner points, to the DIP-MLS testing method. This was compared with using only the internal points of the target, determining the optimal image resolution for this testing method. Through this, we demonstrated that the developed method efficiently addresses the limitations of direct experiments or existing mesh-based simulations. It also suggests that digitalization of the experimental-simulation process is achievable to a considerable extent.

• Journal of Food Hygiene and Safety
• /
• v.39 no.2
• /
• pp.109-117
• /
• 2024

This study investigated the microbial contamination of agricultural, livestock, and marine ingredients in 55 meal kits distributed across Gyeonggi-do, South Korea. Of the 55 meal kits, 48 contained agricultural ingredients, 43 contained livestock ingredients, and 16 contained marine ingredients. The detection rate of the total aerobic bacteria in the agricultural, livestock, and marine products was 100%. The average numbers of the total aerobic bacteria were 6.57 log colony-forming units (CFU)/g in the agricultural products, 4.60 log CFU/g in the livestock products, and 5.47 log CFU/g in the marine products. The coliform detection rates in the agricultural, livestock, and marine products were 81.25%, 69.77%, and 43.75%, respectively. The average numbers of coliforms were 2.83 log CFU/g in the agricultural products, 1.34 log CFU/g in the livestock products, and 1.12 log CFU/g in the marine products. Escherichia coli was detected in 13 livestock products (30.23%), with levels ranging from 0.70 to 2.36 log CFU/g. Contrastingly, E. coli was detected in only one marine product (6.25%) and was not detected in any agricultural products. The detection rates of fungi in agricultural, livestock, and marine products were 97.92%, 93.02%, and 93.75%, respectively. The average numbers of fungi were 3.82 log CFU/g for the agricultural products, 2.92 log CFU/g for the livestock products, and 2.82 log CFU/g for the marine products. The isolation rates of foodborne pathogens from the agricultural, livestock, and marine products were 35.42%, 37.21%, and 31.25%, respectively. Forty-five foodborne pathogens of seven species, including Bacillus cereus and Salmonella spp., were isolated from the raw materials of the agricultural, livestock, and marine products in 55 meal kits. To prevent foodborne diseases caused by meal kits, it is necessary to focus on washing, heating, and preventing cross-contamination during cooking.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.41 no.3
• /
• pp.13-26
• /
• 2023

Landscapes and gardens have emerged as an important medium of practice in contemporary cities. Among them, this paper examines the city through the frame of gardens. This is because gardens are being reconceptualized as a medium of activity for urban residents and have become an important subject of action in urban regeneration and the creation of urban villages. From this perspective, this paper examines and proposes an "integrated garden city theory" as a landscape theory suitable for the contemporary era by focusing on the urban structure and the behavior of urban residents through the medium of gardens, as well as the process and results. This is both a process and a result of looking back at the evolution of landscape for over a century and rethinking the identity of landscape. We first examined garden city theory, noting that Ebenezer Howard and Frederick Law Olmsted's positions on the relationship between gardens and cities were not so different, and that "working and responsive landscapes" were fundamental to cities and the beginning of landscape theory. We also examine how their ideals have not been fully realized in cities over the past century, but the prototype of gardens based on traditional garden culture is now being formed in East Asian cities, and the evolution of landscape theory in response. The conclusion is that a new version of the garden concept should be reestablished as a living infrastructure in our cities, and a new garden city theory is needed to make it work. To this end, each chapter examines three arguments, as follows First, the values of gardens and East Asian garden cultures in contemporary cities are shaped by the themes of community and integrity. Second, Korean communality, represented by apartments, is expressed through gardening and requires the reconciliation of city and life and the role of landscape architecture as a specialized field to support it. Third, we examine and consider an integrated garden city theory as a theory of practice in which city-based, everyday life, and garden mediums, i.e., city, life, and garden, are organic, based on an oriental view of nature. As a result, it is confirmed that contemporary gardens and cities are looking for important elements and values that still need to be rediscovered in East Asian landscape and garden cultures. Although the proposal of an integrated garden city theory cannot guarantee the continuation of landscaping, it can be an opportunity for all fields related to cities, not just landscaping, to collaborate and consider garden cities. Through this, it is hoped that "the concept of garden and city suitable for metropolitan or dense cities, ways to spread and support garden culture based on community, evolution of landscape theory/design theory suitable for lifestyle and terrain conditions, search for sustainable/resilient garden city theory that can respond to climate change, and establishing a new role for landscape in the 21st century" will be seriously considered.

• Korean Journal of Environmental Biology
• /
• v.41 no.4
• /
• pp.473-481
• /
• 2023

Pinus densiflora is a fixed-growth coniferous species that elongates its shoot once a year and finishes growing in early summer. However, it may produce additional shoots in the same year in response to external stimuli, called abnormal shoot growth. This study investigated the effects of open-field summer warming and drought on the abnormal shoot growth of P. densiflora seedlings. In March 2022, two factorial combinations were constructed, including two temperature treatments (control and 4℃ increase) and two precipitation treatments (control and drought), with five replicates for each combination. The temperature treatment was performed for 87 days from May 14 to August 8, 2022, and the precipitation treatment was performed for 33 days from May 14 to June 15, blocking 100% of the ambient rainfall. The abnormal shoot occurrence rate and leaf unfolding stages were measured in November, and the shoot and root collar diameter growth rates were calculated by comparing the seedling height and root collar diameter measured in August(after the cessation of treatment) and October(after the end of growing period) with the initial values (i.e., May 2022). The abnormal shoot occurrence rate significantly increased under the warming treatment, showing a 410.6% increase in the warming plots (38.4%) compared to the control plots (7.5%). There was no significant difference in the shoot and root collar diameter growth rate regarding warming and drought treatments. Abnormal shoots may have been affected by high temperatures by inducing early transition to the next ontogenetic stage.

• Journal of The Korean Association For Science Education
• /
• v.44 no.4
• /
• pp.325-341
• /
• 2024

This study examined how specific aspects of epistemic cognition are developed in elementary students during modeling activities, using the Apt-AIR framework. The study focused on a class unit titled 'Shall We Find Out What the Landscape of a Riverside Looks Like?' which is part of the land chapter in the third-grade Korean elementary science curriculum. Ambitious Science Teaching (AST) was applied as a teaching strategy to enhance students' model construction. Seven science classes were conducted in line with the core practices of AST, with 29 elementary school students participating in the study. The classes were organized into four stages: initial model composition, inquiry activity, group model composition-sharing, and final model construction. The class activities at each stage were analyzed using both the AIR model, i.e., epistemic aim and value (A), epistemic ideals (I), and reliable epistemic processes (R), and the multi-faceted framework for epistemic thinking from the Apt-AIR framework. The results of the study revealed that in science classes emphasizing modeling activities based on the core practices of AST, the elementary students progressively developed more sophisticated explanatory models that included causal relationships explaining the topographic differences between the upstream and downstream sections of a river. This result was due to their engagement in constructing initial models to describe phenomena, supplementing the initial models using data collected in the model experiment, and participating in discussions to share and evaluate group models. Additionally, from the perspective of the Apt-AIR framework, the aspects of epistemic cognition demonstrated by the elementary students in their modeling activities were appropriate for engaging with cognitive processes related to epistemic aims and values, epistemic ideals, and reliable processes. The other four aspects of the Apt-AIR framework, however, were not performed as effectively. In particular, the application of reliable epistemic processes for knowledge construction required more improvement.

• Journal of the Korean Applied Science and Technology
• /
• v.41 no.3
• /
• pp.745-755
• /
• 2024

Calystegia pubescens Lindl. (C. pubesens) is a native Korean herb that has been traditionally used for its diuretic, fatigue, and blood sugar-lowering effects. In previous studies, C. pubesens has shown antioxidant and whitening effects, but research on its antibacterial and anti-inflammatory properties is limited, and its potential as functional materials is lacking. In this study, we investigated the antibacterial, antioxidant, and anti-inflammatory effects of leaf (CPL) and stem (CPS) extracts of C. pubesens extracted with 70% ethanol. When the anti-bacterial effect was confirmed, CPL showed superior anti-bacterial effect than CPS for C. acne, S. aureus, E. coli and P. aeruginosa. Additionally, CPL exhibited significantly higher antioxidant activity compared to CPS, as demonstrated by DPPH and ABTS⁺ radical scavenging assays. Therefore, CPL showed superior anti-bacterial and antioxidant effects compared to CPS. Based on these results, further investigation was conducted to confirm the anti-inflammatory effect of CPL using RAW264.7 macrophages. Nitric oxide (NO) produced by lipopolysaccharide (LPS) stimulation was significantly reduced by CPL treatment in a dose-dependent manner. Additionally, the protein and mRNA expression of iNOS was reduced by CPL in LPS-indueced RAW264.7 cells, which was consistent with NO production. In conclusion, this study confirmed that CPL has superior anti-bacterial and antioxidant effects compared to CPS, and demonstrated anti-inflammatory effect of CPL via inhibiting iNOS expression and NO production induced by LPS. Based on the result, we suggest the potential of CPL as a valuable functional materials.

• Korean Journal of Clinical Laboratory Science
• /
• v.56 no.3
• /
• pp.217-227
• /
• 2024

In this paper, the factors affecting tissues during fixation on slides were determined by changing the tissue type, fixation time, and temperature. Also, stainability and DNA conservation were evaluated. The tissues selected were parenchymal and intestinal tissue. The stainability was evaluated using hematoxylin and eosin staining and a special stain suitable for the tissue. DNA conservation was evaluated using the DNA integrity number (DIN) for stability evaluation after purity measurement. The results showed that, at all temperatures, as time increased, there was no histomorphological difference and the stainability tended to intensify. The intestinal tissue tended to have less mucosal change and proper muscle layer degeneration. There was little difference in the purity. However, the longer the fixation time, the lower the DIN value for DNA. Significant differences were identified at 25℃ and 50℃. This means that fixation at 4℃ is the more safe for DNA. This experiment confirmed that, between the time and temperature conditions associated with fixation, time had a greater effect on both staining and DNA conservation. The results of this study are expected to provide basic data for future research on the setting appropriate conditions for fixation for histopathological examinations or diagnoses.