• Title/Summary/Keyword: Diversity-stability

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Gender Diversity and Financial Stability: Evidence from Malaysian Listed Firms

  • AL-ABSY, Mujeeb Saif Mohsen;ALMAAMARI, Qais;ALKADASH, Tamer;HABTOOR, Ammar
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.181-193
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    • 2020
  • This study examines the relationship between gender diversity (women on the board and women on the audit committee) and a firm's financial stability. The ordinary least square analysis was used to determine the relationship. To measure the financial stability of Malaysian suspect firms, i.e., firms with the lowest positive earnings, the Altman (1993) Z-Score measurement was utilized. The results indicate that women on the board are significantly and negatively associated with the firm's financial stability. That is, they are related to low financial stability, which contradicts the agency and resource dependence theories. Regarding women directors on the audit committee, there is no significant relationship with financial stability, meaning that they cannot protect the company against financial distress. These results are robust and do not change when using different measurements of gender diversity, one-year lag of independent variables, and other methods of analysis, namely random effect panel data. This study is the first to alert policymakers, stakeholders, researchers, and society in general to the need to re-evaluate and strengthen the role of women directors in improving firms' financial stability, particularly in emerging economies like Malaysia.

Stability Analysis of Soil Oribatid Mite Communities (Acari: Oribatida from Namsan and Kwangreung Deciduous Forests, Korea

  • Jung, Chulue;Lee, Joon-Ho
    • The Korean Journal of Ecology
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    • v.24 no.4
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    • pp.239-243
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    • 2001
  • One of the most important justifications of conservation of ecosystem and biodiversity is that diversity begets stability. Impact of biodiversity on community and ecosystem function has long been debated in science. Here we report the stability analysis of soil oribatid mite communities from environmentally stressed habitat(Namsan) and relatively well preserved habitat (Kwangreung) with the perspective of consistency as a primary criteria of stability. Stability of oribatid mite communities were evaluated with turnover rate, constancy analysis, b diversity index, and absolute abundance, abundance ranking, and the presence or absence of species over time. Out of 6 criteria, three consented that oribatid community from Kwangreung was more stable than that from Namsan. Those are turnover rate in litter layer, constancy analysis, and absolute abundance. Feasibility of stability analysis using oribatid mites was further discussed, rendering further study.

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Heterogeneous Habitat for Increasing Biological Diversity

  • Lee, Sang-Don
    • Korean Journal of Environmental Biology
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    • v.21 no.4
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    • pp.337-341
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    • 2003
  • Habitat heterogeneity can enhance biological diversity by providing variation in structural diversity. This paper reviewed heterogeneous habitat serves as a population stability and superior demographic performance (e.g., high density, survivorship, reproductive rate) can be observed compared with organisms with inferior demographic performance. The idea of habitat variation has been further developed in modelling. Furthermore the size and configuration (distribution) of a patch (of a particular habitat type) become effective for the stability of population through hiding places and food resources. Species diversity is related to habitat complexity that provides structural diversity to ground -dwelling organisms. Finally coarse woody debris can enhance habitat complexity thus stabilizing population fluctuation and increasing survivorship.

Effect of Non-indigenous Bacterial Introductions on Rhizosphere Microbial Community

  • Nogrado, Kathyleen;Ha, Gwang-Su;Yang, Hee-Jong;Lee, Ji-Hoon
    • Korean Journal of Environmental Agriculture
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    • v.40 no.3
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    • pp.194-202
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    • 2021
  • BACKGROUND: Towards achievement of sustainable agriculture, using microbial inoculants may present promising alternatives without adverse environmental effects; however, there are challenging issues that should be addressed in terms of effectiveness and ecology. Viability and stability of the bacterial inoculants would be one of the major issues in effectiveness of microbial pesticide uses, and the changes within the indigenous microbial communities by the inoculants would be an important factor influencing soil ecology. Here we investigated the stability of the introduced bacterial strains in the soils planted with barley and its effect on the diversity shifts of the rhizosphere soil bacteria. METHODS AND RESULTS: Two different types of bacterial strains of Bacillus thuringiensis and Shewanella oneidensis MR-1 were inoculated to the soils planted with barley. To monitor the stability of the inoculated bacterial strains, genes specific to the strains (XRE and mtrA) were quantified by qPCR. In addition, bacterial community analyses were performed using v3-v4 regions of 16S rRNA gene sequences from the barley rhizosphere soils, which were analyzed using Illumina MiSeq system and Mothur. Alpha- and beta-diversity analyses indicated that the inoculated rhizosphere soils were grouped apart from the uninoculated soil, and plant growth also may have affected the soil bacterial diversity. CONCLUSION: Regardless of the survival of the introduced non-native microbes, non-indigenous bacteria may influence the soil microbial community and diversity.

Shannon의 함수

  • Yi, Beom-Jun
    • 한국해양학회지
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    • v.14 no.1
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    • pp.32-38
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    • 1979
  • The original concept and theory of Shannon's function H=-$\Sigma$(i-1,n)Pi, log$\_$2/Pi and its applicable domains in ecology are discussed. The confusions exist in use and interpretation of this function are due to: 1. Mixing the idea of proper ecological diversity with that of Shannon's information theory. 2. Confusion of physical or thermodynamical systems with ecological systems. 3. Confusion of the system from which one had calculated function H with the system of which function H is interpreted. It's proposed to use function H for the comparison of community's structure and so, for the distinction of community's evolution (succession) steps.

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3'UTR Diversity: Expanding Repertoire of RNA Alterations in Human mRNAs

  • Dawon Hong;Sunjoo Jeong
    • Molecules and Cells
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    • v.46 no.1
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    • pp.48-56
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    • 2023
  • Genomic information stored in the DNA is transcribed to the mRNA and translated to proteins. The 3' untranslated regions (3'UTRs) of the mRNA serve pivotal roles in post-transcriptional gene expression, regulating mRNA stability, translation, and localization. Similar to DNA mutations producing aberrant proteins, RNA alterations expand the transcriptome landscape and change the cellular proteome. Recent global analyses reveal that many genes express various forms of altered RNAs, including 3'UTR length variants. Alternative polyadenylation and alternative splicing are involved in diversifying 3'UTRs, which could act as a hidden layer of eukaryotic gene expression control. In this review, we summarize the functions and regulations of 3'UTRs and elaborate on the generation and functional consequences of 3'UTR diversity. Given that dynamic 3'UTR length control contributes to phenotypic complexity, dysregulated 3'UTR diversity might be relevant to disease development, including cancers. Thus, 3'UTR diversity in cancer could open exciting new research areas and provide avenues for novel cancer theragnostics.

Species Composition and Stand Structure of Natural Forest, Timber-harvested Forest and Degraded Forest in the Bago Yoma Region of Myanmar

  • Oo, Thaung Naing;Lee, Don Koo
    • Journal of Korean Society of Forest Science
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    • v.96 no.5
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    • pp.572-579
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    • 2007
  • Tree species diversity is an important aspect of forest ecosystem stability. Tree species inventories at defined sites and in minimum diameter classes give a reliable indicator of the diversity level as well as the structural stability level of a study site. This study was conducted to investigate the species composition and the stand structure of the natural forest, timber-harvested forest (logged-over forest) and degraded forest of the Oak-twin Township in the Bago Yoma Region of Myanmar. Natural forest showed the highest family and species richness in all the investigated forests. At the family level, Verbenaceae occupied the highest importance value index (IVI) in all the forest stands while teak (Tectona grandis Linn. f.) occupied the highest IVI at the species level. However, the small diameter classes of T. grandis and other commercial species were less than those of big diameter classes in all the investigated forests. This abnormal pattern of diameter distribution could be a problem for the sustainable production of commercial timber species in the near future.

Design of optimum criterion for opportunistic multi-hop routing in cognitive radio networks

  • Yousofi, Ahmad;Sabaei, Masoud;Hosseinzadeh, Mehdi
    • ETRI Journal
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    • v.40 no.5
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    • pp.613-623
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    • 2018
  • The instability of operational channels on cognitive radio networks (CRNs), which is due to the stochastic behavior of primary users (PUs), has increased the complexity of the design of the optimal routing criterion (ORC) in CRNs. The exploitation of available opportunities in CRNs, such as the channel diversity, as well as alternative routes provided by the intermediate nodes belonging to routes (internal backup routes) in the route-cost (or weight) determination, complicate the ORC design. In this paper, to cover the channel diversity, the CRN is modeled as a multigraph in which the weight of each edge is determined according to the behavior of PU senders and the protection of PU receivers. Then, an ORC for CRNs, which is referred to as the stability probability of communication between the source node and the destination node (SPC_SD), is proposed. SPC_SD, which is based on the obtained model, internal backup routes, and probability theory, calculates the precise probability of communication stability between the source and destination. The performance evaluation is conducted using simulations, and the results show that the end-to-end performance improved significantly.

Function of Habitat Heterogeneity for the Biodiversity and Demography of Population in Small Mammal Community (소척추동물군집에서 개체군 변동과 생물다양성 유지를 위한 서식지 이질성의 기능)

  • Lee, Sang Don
    • The Korean Journal of Ecology
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    • v.18 no.4
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    • pp.512-523
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    • 1995
  • The central theme of Habital heterogeneity is to provide animals with habital complexity or structural diversity and to allow resource partitioning among individuals. In turn, the leads to population stability because prey can escape more easily with more hiding places causing less population fluctuation. Species diversity is characterized due to more potential niches both horizontally and verticall. Empirically, in homogeneous habitats population was less abundant, reproduction and survival were lower, spacing behavior, competition and dispersal were higher than in heterogeneous habitats. The results imply that diversity and conservation of species can be maintained through providing heterogeneous habitats.

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Stability of Early Language Development of Verbally-Precocious Korean Children from 2 to 3 Year-old (조기언어발달 아동의 초기 언어능력의 안정성)

  • Lee, Kwee-Ock
    • The Korean Journal of Community Living Science
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    • v.19 no.4
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    • pp.673-684
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    • 2008
  • The purpose of this study is to compare the complexity of language level between verbally-precocious and typically-developing children from 2 to 3 years-old. Participants were 15 children classified as verbally-precocious were scored at the mean 56.85(expressive language) and 88.82(receptive language), and another 15 children classified as typically developing did at the mean 33.51(expressive language) and 58.01(receptive language) on MCDI-K. Each child's spontaneous utterances in interaction with her caregiver were collected at three different times with 6 months interval. All of the utterances were transcribed and analyzed for the use of MLU and lexical diversity by using KCLA. Summarizing the overall results, verbally-precocious children had significantly higher language abilities than typically-developing children at each time, and there were significant differences between two groups in syntactic and semantic language development, showing that verbally-precocious children indicated distinctive MLU and lexical diversity. These results suggest a high degree of stability in precocious verbal status, with variations in language complexity during conversations contributing to later differences in their language ability.

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