• Title/Summary/Keyword: Adaptive response

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Promotion of Plant Growth by Submergence and the Action Network of Hormones (침수에 의한 식물의 생장 촉진과 호르몬들의 작용 네트워크)

  • Cho Young Jun;Lee Young Na;Park Woong June
    • Journal of Life Science
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    • v.15 no.1 s.68
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    • pp.112-117
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    • 2005
  • Plants living riverside show diverse resistance responses to submergence. The promoted petiole elongation of semi-aquaitc plants, e.g., such as Ranunculus sceleratus and Rumex palustris, is one of the adaptive responses mediated by the plant hormone ethylene. The gaseous hormone is trapped in submerged plant tissues and enhances the petiole growth by increasing sensitivity of the tissues to some plant hormones including auxin. Due to the stimulated growth of petioles, the leaves finally reach the water surface and can respirate again. At the water surface, the accumulated ethylene diffuses out from the tissues to the air. As a result, the increased hormone sensitivity decreases again, and thus the growth rate reduces to the basal level as before. The increased auxin sensitivities by ethylene observed in Ranunculus sceleratus, revealed by the changes in the auxin dose-response curves, indicate the increase of affinities of the receptors to auxin. However, the molecular mechanism of the affinity regulation remains still largely unknown, because the identity of the auxin receptor is still unclear.

A Study on Evaluation Method of ACC Test Considering Domestic Road Environment (국내도로 환경을 고려한 ACC 시험평가 방법에 관한 연구)

  • Kim, BongJu;Lee, SeonBong
    • Journal of Auto-vehicle Safety Association
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    • v.9 no.4
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    • pp.38-47
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    • 2017
  • With automobiles sharply increasing worldwide, we are faced with serious social problems such as traffic accidents, traffic jams, environmental pollution, and economic inefficiency. In response, research on ITS is promoted mainly by regions with advanced automotive industry such as the US, Europe, and Japan. While Korea is working to get ahead to take global market through developing and turning into global standards systems related to ASV(Advanced Safety Vehicle), the country is not excellently prepared for such projects. The purpose of ACC is to control the vehicle's longitudinal speed and distance and minimize driver workload. Such a system should be useful in preventing accidents, as it reduces driver workload in the 21st-century world of telematics created by the development of automobile culture industry. In this light, the thesis presents a method to test and evaluate ACC system and a mathematical method to assess distance. Furthermore, for the proposed test and evaluation, theoretical values are tested with vehicle test and a database is acquired, by using vehicles equipped with an ACC system. We proposed the scenarios suitable for the domestic environment and conducted the actual road test. Theoretical evaluation criteria for developing ACC system may be employed and scenario-specific evaluation methods may find their useful application through testing the formula proposed by comparing the database and the mathematical method. and, many companies are expected to utilize the scenario in the developing stage of ACC, and be able to employ as a verification method by harnessing theoretical formula before a road test.

An Effective addressing assignment method and Its Routing Algorithm in Smart Grid Environments (스마트그리드 환경에서 효율적인 주소 할당 방법과 라우팅 알고리즘)

  • Im, Song-Bin;Kim, Hwa-Sung;Oh, Young-Hwan
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.10
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    • pp.89-98
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    • 2012
  • In this paper, we proposed the efficient addressing scheme for improving the performance of routing algorithm by using ZigBee in Smart Grid environment. In a 16-bit address space and the network size of a few thousands, it is very unlikely to suffer from frequent address collisions. In response, we propose an elegant (x, y, z) coordinate axes addressing scheme from divided address space of 16 bit and its routing algorithm. One of disadvantages of (x, y) coordinate axes addressing, however, is that any router may not hold as many children as proposed, since sensor nodes tend to be connected to a geographically nearby router. We also present an adaptive routing algorithm for location-aware routing algorithms, using our addressing scheme. As a result, each node was reduced not only bitwise but also multi hop using the coordinate axes while routing and the effective address assignment and routing is to minimize the average energy consumption of each node in the network.

Detecting response patterns of zooplankton to environmental parameters in shallow freshwater wetlands: discovery of the role of macrophytes as microhabitat for epiphytic zooplankton

  • Choi, Jong-Yun;Kim, Seong-Ki;Jeng, Kwang-Seuk;Joo, Gea-Jae
    • Journal of Ecology and Environment
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    • v.38 no.2
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    • pp.133-143
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    • 2015
  • Freshwater macrophytes improve the structural heterogeneity of microhabitats in water, often providing an important habitat for zooplankton. Some studies have focused on the overall influence of macrophytes on zooplankton, but the effects of macrophyte in relation to different habitat characteristics of zooplankton (e.g., epiphytic and pelagic) have not been intensively studied. We hypothesized that different habitat structures (i.e., macrophyte habitat) would strongly affect zooplankton distribution. We investigated zooplankton density and diversity, macrophyte characteristics (dry weight and species number), and environmental parameters in 40 shallow wetlands in South Korea. Patterns in the data were analyzed using a self-organizing map (SOM), which extracts information through competitive and adaptive properties. A total of 20 variables (11 environmental parameters and 9 zooplankton groups) were patterned onto the SOM. Based on a U-matrix, 3 clusters were identified from the model. Zooplankton assemblages were positively related to macrophyte characteristics (i.e., dry weight and species number). In particular, epiphytic species (i.e., epiphytic rotifers and cladocerans) exhibited a clear relationship with macrophyte characteristics, while large biomass and greater numbers of macrophyte species supported high zooplankton assemblages. Consequently, habitat heterogeneity in the macrophyte bed was recognized as an important factor to determine zooplankton distribution, particularly in epiphytic species. The results indicate that macrophytes are critical for heterogeneity in lentic freshwater ecosystems, and the inclusion of diverse plant species in wetland construction or restoration schemes is expected to generate ecologically healthy food webs.

Analytical and higher order finite element hybrid approach for an efficient simulation of ultrasonic guided waves I: 2D-analysis

  • Vivar-Perez, Juan M.;Duczek, Sascha;Gabbert, Ulrich
    • Smart Structures and Systems
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    • v.13 no.4
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    • pp.587-614
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    • 2014
  • In recent years the interest in online monitoring of lightweight structures with ultrasonic guided waves is steadily growing. Especially the aircraft industry is a driving force in the development of structural health monitoring (SHM) systems. In order to optimally design SHM systems powerful and efficient numerical simulation tools to predict the behaviour of ultrasonic elastic waves in thin-walled structures are required. It has been shown that in real industrial applications, such as airplane wings or fuselages, conventional linear and quadratic pure displacement finite elements commonly used to model ultrasonic elastic waves quickly reach their limits. The required mesh density, to obtain good quality solutions, results in enormous computational costs when solving the wave propagation problem in the time domain. To resolve this problem different possibilities are available. Analytical methods and higher order finite element method approaches (HO-FEM), like p-FEM, spectral elements, spectral analysis and isogeometric analysis, are among them. Although analytical approaches offer fast and accurate results, they are limited to rather simple geometries. On the other hand, the application of higher order finite element schemes is a computationally demanding task. The drawbacks of both methods can be circumvented if regions of complex geometry are modelled using a HO-FEM approach while the response of the remaining structure is computed utilizing an analytical approach. The objective of the paper is to present an efficient method to couple different HO-FEM schemes with an analytical description of an undisturbed region. Using this hybrid formulation the numerical effort can be drastically reduced. The functionality of the proposed scheme is demonstrated by studying the propagation of ultrasonic guided waves in plates, excited by a piezoelectric patch actuator. The actuator is modelled utilizing higher order coupled field finite elements, whereas the homogenous, isotropic plate is described analytically. The results of this "semi-analytical" approach highlight the opportunities to reduce the numerical effort if closed-form solutions are partially available.

Development of WebCAT System for ICT Knowledge Ability Evaluation (ICT 소양능력 평가를 위한 WebCAT 시스템의 개발)

  • Lee, Young-Hyoun;Jung, Young-Sik;Kim, Myeong-Ryeol
    • Journal of The Korean Association of Information Education
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    • v.8 no.2
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    • pp.261-268
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    • 2004
  • The Government has established the infrastructure for knowledge and information-oriented society, strengthening the ICT technology education. Although information knowledge ability of learners is prerequisite to educate ICT, but systematic educating courses and time for that are insufficient, and many difficulties have been pointed out. In order to solve such problems, this study developed Web-based computerized adaptive testing system using the item response theory. This system enables the learners to evaluate their own ICT knowledge abilities in their school or home by using familiar web interface and to perform supplementary or deepening study according to the results, and consequently, smooth education of ICT application will be achieved. In addition, this system will be a very effective method for the elementary/middle/high-school ICT knowledge ability certification system.

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Hepatic and Renal cysteine Sulfinic Acid Decarboxylase Activities in Cats Fed Different Levels of Dietary Protein and Taurine

  • Park, Taesun;Quinton R. Rogers
    • Preventive Nutrition and Food Science
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    • v.4 no.1
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    • pp.47-51
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    • 1999
  • In order to evaluate the dietary regulation of cysteine sulfinic acid decarboxylase (EC 4.1.1.29) in cats, acitivity and protein content of CSAD were assessed in the liver and kidney of cats fed different levels of dietary protein, with and without taurine. Four groups of cats were fed one of the follow diets for 5 weeks ; 20% protein and taurine- free diet(LP0T) ; 20% protein and 0.15% taurine diet(LPNT) ; 60% protein and taurine-free diet(HP0T); and 60% protein and 0.15% taurine diet (HPNT). CSAD activity was determined in the liver and kidney of cats by measuring 14C2 released form [1-14C]-L cysteine sulfinic acid. CSAD protein was quantified using an immunochemical method. CSAD activity was extremely low in cat tissues, among which kidney showed the highest activity which was 0.118$\pm$0.050, and 0.377$\pm$0.056 nmol.min-1.mg soluble portein-1 iin animals fed LP0T and HP0T, respectively. Even though renal CSAD protein content was 18~55% of the hepatic CSAD protein content, renal CSAD acitivity was 1.3~6.5 times of the hepatic CSAD activity . Renal CSAD acitivities of cats fed 60% protein were about 1.6~3.2 times those of animals fed 2.% protein , and hepatic CSAD activity was not significantly affected by the dietary level of protein. Taurine depletion significantly elevated both hepatic and renal CSAD activities above the values for cats having normal taurine status most probably as an adaptive response.

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Renal transplantation in a patient with Bartter syndrome and glomerulosclerosis

  • Lee, Se-Eun;Han, Kyoung-Hee;Jung, Yun-Hye;Lee, Hyun-Kyung;Kang, Hee-Gyung;Moon, Kyung-Chul;Ha, Il-Soo;Choi, Yong;Cheong, Hae-Il
    • Clinical and Experimental Pediatrics
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    • v.54 no.1
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    • pp.36-39
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    • 2011
  • Bartter syndrome (BS) is a clinically and genetically heterogeneous inherited renal tubular disorder characterized by renal salt wasting, hypokalemic metabolic alkalosis and normotensive hyperreninemic hyperaldosteronism. There have been several case reports of BS complicated by focal segmental glomerulosclerosis (FSGS). Here, we have reported the case of a BS patient who developed FSGS and subsequent end-stage renal disease (ESRD) and provided a brief literature review. The patient presented with classic BS at 3 months of age and developed proteinuria at 7 years. Renal biopsy performed at 11 years of age revealed a FSGS perihilar variant. Hemodialysis was initiated at 11 years of age, and kidney transplantation was performed at 16 years of age. The post-transplantation course has been uneventful for more than 3 years with complete disappearance of BS without the recurrence of FSGS. Genetic study revealed a homozygous p.Trp(TGG)610Stop(TGA) mutation in the CLCNKB gene. In summary, BS may be complicated by secondary FSGS due to the adaptive response to chronic salt-losing nephropathy, and FSGS may progress to ESRD in some patients. Renal transplantation in patients with BS and ESRD results in complete remission of BS.

Conditioning-induced cardioprotection: Aging as a confounding factor

  • Randhawa, Puneet Kaur;Bali, Anjana;Virdi, Jasleen Kaur;Jaggi, Amteshwar Singh
    • The Korean Journal of Physiology and Pharmacology
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    • v.22 no.5
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    • pp.467-479
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    • 2018
  • The aging process induces a plethora of changes in the body including alterations in hormonal regulation and metabolism in various organs including the heart. Aging is associated with marked increase in the vulnerability of the heart to ischemia-reperfusion injury. Furthermore, it significantly hampers the development of adaptive response to various forms of conditioning stimuli (pre/post/remote conditioning). Aging significantly impairs the activation of signaling pathways that mediate preconditioning-induced cardioprotection. It possibly impairs the uptake and release of adenosine, decreases the number of adenosine transporter sites and down-regulates the transcription of adenosine receptors in the myocardium to attenuate adenosine-mediated cardioprotection. Furthermore, aging decreases the expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha ($PGC-1{\alpha}$) and subsequent transcription of catalase enzyme which subsequently increases the oxidative stress and decreases the responsiveness to preconditioning stimuli in the senescent diabetic hearts. In addition, in the aged rat hearts, the conditioning stimulus fails to phosphorylate Akt kinase that is required for mediating cardioprotective signaling in the heart. Moreover, aging increases the concentration of $Na^+$ and $K^+$, connexin expression and caveolin abundance in the myocardium and increases the susceptibility to ischemia-reperfusion injury. In addition, aging also reduces the responsiveness to conditioning stimuli possibly due to reduced kinase signaling and reduced STAT-3 phosphorylation. However, aging is associated with an increase in MKP-1 phosphorylation, which dephosphorylates (deactivates) mitogen activated protein kinase that is involved in cardioprotective signaling. The present review describes aging as one of the major confounding factors in attenuating remote ischemic preconditioning-induced cardioprotection along with the possible mechanisms.

Causal study on the effect of survey methods in the 19th presidential election telephone survey (19대 대선 전화조사에서 조사방법 효과에 대한 인과연구)

  • Kim, Ji-Hyun;Jung, Hyojae
    • The Korean Journal of Applied Statistics
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    • v.30 no.6
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    • pp.943-955
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    • 2017
  • We investigate and estimate the causal effect of the survey methods in telephone surveys for the 19th presidential election. For this causal study, we draw a causal graph that represents the causal relationship between variables. Then we decide which variables should be included in the model and which variables should not be. We explain why the research agency is a should-be variable and the response rate is a shouldnot-be variable. The effect of ARS can not be estimated due to data limitations. We have found that there is no significant difference in the effect of the proportion of cell phone survey if it is less than about 90 percent. But the support rate for Moon Jae-in gets higher if the survey is performed only by cell phones.