Ecological risk assessment of hydropower dam construction based on ecological network analysis

Dam construction is regarded as one of the major factors contributing to significant modifications of the river ecosystems, and the ecological risk (ER) assessment of dam construction has received growing attention in recent years. In the present study, we explored the potential ecological risk caused by dam project based on the general principles of the ecological risk assessment. Ecological network analysis was proposed as the usable analytic method for the implement of ecological risk assessment, thus contributing to the modelling of dam-induced risk process. Applying ecological network analysis to the ecological risk assessment of river ecosystems after dam construction, this study may provide important insights into the understanding of how an affected river ecosystem reacts to the artificial perturbation on a whole-ecosystem scale

Ecological network analysis of embodied particulate matter 2.5 – A case study of Beijing

Over the past decades, China has been facing severe airborne pollution associated with atmospheric fine particulate matter (PM2.5). Much attention has been paid to the physical transport of PM2.5 emissions. However, the embodied emissions, namely the emissions transferred through economic activities, have seldom been investigated. In this paper, embodied emission of PM2.5 from each sector of Beijing is quantified based on input–output analysis (IOA). Forty-two economic sectors from the input–output table are aggregated into fifteen components. Furthermore, the mutual interactions and control relationship within those sectors have been revealed by using ecological network analysis (ENA) to identify the dominant sectors. The results show that, in 2010, 34% of the total PM2.5 emissions, or 59.4 kt PM2.5, were indirect emissions traded through economic sectors within Beijing. According to the results of ENA, we found that “Smelting & Pressing of Metals“, “Metal Products” and “Nonmetal Mineral Products“ are the top three sectors with the highest control levels while “Agriculture”, “Catering Services” and “Residential Services” are the lowest-ranking sectors among the system. The network confirms that sectors related to heavy industry are the dominant sectors driving the embodied PM2.5 emissions in the whole system. Compared to the conventional approaches for tracking PM2.5 emissions, ENA may provide a practical way to reveal the mechanisms of embodied PM2.5 emission flows via socioeconomic activities from a holistic perspective

Information indices from ecological network analysis for urban metabolic system

The system analysis of urban metabolic system, still a black box in urban research, has been underlined recently due to its important role in assessing the sustainability of urban ecosystem. An interpretation of the information indices from ecological network analysis when combined with urban metabolic research, however, has not been addressed systematically. In this study, a conceptual network model of urban metabolic systems was developed based on the identification of seven compartments. Emergy analysis and extended exergy analysis were introduced in order to define the proper way of quantifying the material and energy flows within the system. After that, the information indices derived from ecological network analysis such as developmental capacity, ascendancy, overload were proposed as the potential indicators reflecting the sustainability of urban development. An interpretation of these information indices when embedded into urban metabolic system was conducted to further demonstrate their potential application to urban research. With the qualification and interpretation of these information indices from network analysis, this study may provide some lights on unfolding the black box

Graphene zigzag ribbons, square lattice models and quantum spin chains

We present an extended study of finite-width zigzag graphene ribbons (ZGRs) based on a tight-binding model with hard-wall boundary conditions. We provide an exact analytic solution that clarifies the origin of the predicted width dependence on the conductance through junctions of ribbons with different widths. An analysis of the obtained solutions suggests a new description of ZGRs in terms of coupled chains. We pursue these ideas further by introducing a mapping between the ZGR model and the Hamiltonian for N-coupled quantum chains as described in terms of 2N Majorana fermions. The proposed mapping preserves the dependence of ribbon properties on its width thus rendering metallic ribbons for N odd and zero-gap semiconductor ribbons for N even. Furthermore, it reveals a close connection between the low-energy properties of the ZGR model and a continuous family of square lattice model Hamiltonians with similar width-dependent properties that includes the $\pi-$flux and the trivial square lattice models. As a further extension, we show that this new description makes it possible to identify various aspects of the physics of graphene ribbons with those predicted by models of quantum spin chains (QSCs)

Interactive effects of joint angle, contraction state and method on estimates of Achilles tendon moment arms

The muscle-tendon moment arm is an important input parameter for musculoskeletal models. Moment arms change as a function of joint angle and contraction state and depend on the method being employed. The overall purpose was to gain insights into the interactive effects of joint angle, contraction state and method on the Achilles tendon moment arm using the center of rotation (COR) and the tendon excursion method (TE). Moment arms were obtained at rest (TErest, CORrest) and during a maximum voluntary contraction (CORMVC) at four angles. We found strong correlations between TErest and CORMVC for all angles (0.72 ≤ r ≤ 0.93) with Achilles tendon moment arms using CORMVC being 33 - 36% greater than those obtained from TErest. The relationship between Achilles tendon moment arms and angle was similar across both methods and both levels of muscular contraction. Finally, Achilles tendon moment arms for CORrest were 1 – 8% greater than for CORMVC. [NB rendition of scientific symbols is approximate in this display; please check full text for precise rendition]

Cell biology:Collagen secretion explained

Cells package proteins into vesicles for secretion to the extracellular milieu. A study shows that an enzyme modifies the packaging machinery to encapsulate unusually large proteins such as collagen

Niche emergence as an autocatalytic process in the evolution of ecosystems

The utilisation of the ecospace and the change in diversity through time has been suggested to be due to the effect of niche partitioning, as a global long-term pattern in the fossil record. However, niche partitioning, as a way to coexist, could be a limited means to share the environmental resources and condition during evolutionary time. In fact, a physical limit impedes a high partitioning without a high restriction of the niche's variables. Here, we propose that niche emergence, rather than niche partitioning, is what mostly drives ecological diversity. In particular, we view ecosystems in terms of autocatalytic sets: catalytically closed and self-sustaining reaction (or interaction) networks. We provide some examples of such ecological autocatalytic networks, how this can give rise to an expanding process of niche emergence (both in time and space), and how these networks have evolved over time (so-called evoRAFs). Furthermore, we use the autocatalytic set formalism to show that it can be expected to observe a power-law in the size distribution of extinction events in ecosystems. In short, we elaborate on our earlier argument that new species create new niches, and that biodiversity is therefore an autocatalytic process

Time and space model of urban pollution migration: Economy-energy-environment nexus network

In recent years, news of “cancer villages” in the Huaihe River Basin filled front and back pages of newspapers and generated elevated concern among readers. This study aims to understand the relationship between the “cancer villages” and the “large cities” around them. A gravity model is constructed to analyze the correlation between “big cities” and “cancer villages” in terms of indices involving economic connections and pollution frequency. Direct and indirect environmental relationships between large cities and “cancer villages” are analyzed using ecological network analysis, in particular the utility analysis method. Results of the pollution-utility analysis showed that cities distant from “cancer villages” can also affect the county through indirect connections. Based on the pollution utility relationship, we found that “cancer villages” both affect and are affected by cities through indirect feedback relationships. It can be inferred that “cancer villages” have a high incidence of malignant disease not only because of the pollution from its surrounding cities but also because of the influence of far-away cities through a network of interactions. In this way, the pollution of “cancer villages” may be heightened with harmful consequences to population health. Considering these indirect connections, not all of the “cancer villages” are able to reduce their pollution by transferring it to another city or county because it can return through indirect pathways. The best approach would be to lower the pollution generation in the first place in order to prevent its impacts, as well as to at least partially mitigate them through more effective medical care

Solitonic excitations in the Haldane phase of a S=1 chain

We study low-lying excitations in the 1D $S=1$ antiferromagnetic valence-bond-solid (VBS) model. In a numerical calculation on finite systems the lowest excitations are found to form a discrete triplet branch, separated from the higher-lying continuum. The dispersion of these triplet excitations can be satisfactorily reproduced by assuming approximate wave functions. These wave functions are shown to correspond to moving hidden domain walls, i.e. to one-soliton excitations.Comment: RevTex 3.0, 24 pages, 2 figures on request by fax or mai

WORSILEAR (Word Square Interactive Learning): Media Pembelajaran Akuntansi Berbasis Aplikasi Sebagai Upaya Peningkatan Pemahaman Akuntansi Dasar Siswa Sekolah Menengah Kejuruan

The challenge in realizing quality education requires educators to be more creative, innovative, and inspiring in designing learning activities. This is carried out as well as preparation to welcome Indonesia's golden generation in 2045. In addition, in the accounting world, the role of educator accountants is very important to form reliable millennial accountants with high competitiveness. This research is a media development research that raises the incorporation of interactive media using the word square learning model with the aim of facilitating the understanding of accounting material for students so that it can motivate students to be enthusiastic about learning and obtain maximum learning outcomes. Learning activities through interactive media are learning using technology-based tools. Meanwhile, the model in word square learning is a learning model with the same level of similarity as the crossword puzzle learning model. In word square learning, answers are available but they are disguised using the addition of letters or numbers, as well as the addition of boxes as a distraction with the aim of training students' critical and conscientious attitude. The method in this study, namely the research and development method of the ADDIE model. Based on the research results that have been obtained, it can be concluded that the learning process is more interesting if it uses a combination of technology-based interactive media with the word square model. This research reaches the design stage of the application to be developed. This research can be improved later with practical trials in the field on students in the classroom