scholarly journals Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile

2022 ◽  
Vol 10 (1) ◽  
Author(s):  
Abigail B. Feuka ◽  
Melia G. Nafus ◽  
Amy A. Yackel Adams ◽  
Larissa L. Bailey ◽  
Mevin B. Hooten
Keyword(s):  
Urban Areas ◽  
Experimental Treatment ◽  
Population Level ◽  
Step Length ◽  
Individual Heterogeneity ◽  
Small Scale ◽  
Boiga Irregularis ◽  
Bayesian Hierarchical ◽  
Treatment Groups ◽  
Movement Parameters

Abstract Background Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam. Methods We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters. Results We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability. Conclusions Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.

Design and Operation of Small Wastewater Treatment Plants by the Microbial Film Process

1990 ◽  
Vol 22 (3-4) ◽  
pp. 139-144 ◽  
Author(s):  
S. Iwai ◽  
Y. Oshino ◽  
T. Tsukada
Keyword(s):  
Urban Areas ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Small Scale ◽  
Small Communities ◽  
Fishing Villages ◽  
Sewer Systems ◽  
Water Treatment Plants ◽  
History Of ◽  
Microbial Film

Although the ratio of sewer systems to population in Japan has been improving in recent years, the construction of sewer systems in small communities such as farming or fishing villages, etc. had lagged behind that of urban areas. However, construction of small-scale sewer systems in farming and fishing villages has been actively carried out in recent years. This report explains the history of the promotion of small-scale sewer systems, why submerged filter beds are being employed in many cases, and introduces the design, operation and maintenance of representative waste-water treatment plants in farming and fishing villages which incorporate de-nitrogen and dephosphorization.

scholarly journals Canard optimization for enhancing the performance of small horizontal axis wind turbine at low wind speeds

2020 ◽  
Vol 37 ◽  
pp. 63-71
Author(s):  
Yui-Chuin Shiah ◽  
Chia Hsiang Chang ◽  
Yu-Jen Chen ◽  
Ankam Vinod Kumar Reddy
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Optimum Parameters ◽  
Low Wind Speeds

ABSTRACT Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

scholarly journals Understanding Spatial Variability of NO2 in Urban Areas Using Spatial Modelling and Data Fusion Approaches

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 179
Author(s):  
Said Munir ◽  
Martin Mayfield ◽  
Daniel Coca
Keyword(s):  
Data Fusion ◽  
Spatial Variability ◽  
Urban Areas ◽  
Road Traffic ◽  
Dispersion Model ◽  
Low Cost ◽  
Spatial Modelling ◽  
City Centre ◽  
Small Scale ◽  
The City

Small-scale spatial variability in NO2 concentrations is analysed with the help of pollution maps. Maps of NO2 estimated by the Airviro dispersion model and land use regression (LUR) model are fused with measured NO2 concentrations from low-cost sensors (LCS), reference sensors and diffusion tubes. In this study, geostatistical universal kriging was employed for fusing (integrating) model estimations with measured NO2 concentrations. The results showed that the data fusion approach was capable of estimating realistic NO2 concentration maps that inherited spatial patterns of the pollutant from the model estimations and adjusted the modelled values using the measured concentrations. Maps produced by the fusion of NO2-LCS with NO2-LUR produced better results, with r-value 0.96 and RMSE 9.09. Data fusion adds value to both measured and estimated concentrations: the measured data are improved by predicting spatiotemporal gaps, whereas the modelled data are improved by constraining them with observed data. Hotspots of NO2 were shown in the city centre, eastern parts of the city towards the motorway (M1) and on some major roads. Air quality standards were exceeded at several locations in Sheffield, where annual mean NO2 levels were higher than 40 µg/m3. Road traffic was considered to be the dominant emission source of NO2 in Sheffield.

Local Communities as a Tool for the Development of Municipal Democracy: German Experience and Lessons for Russia

2020 ◽  
Vol 29 (5) ◽  
pp. 74-88
Author(s):  
Aleksandr Larichev ◽  
Emil Markwart
Keyword(s):  
Local Government ◽  
Urban Areas ◽  
Local Population ◽  
Local Communities ◽  
The State ◽  
Household Waste ◽  
Small Scale ◽  
Issue Management ◽  
State Management ◽  
Municipal Level

Local government as a political, legal and social institution finds itself in a very difficult period of development in Russia. The long-established tendency of its subordination to the state has intensified today in connection with the newly adopted constitutional amendments. At the same time, it seems obvious that further “embedding” of local government into the state management vertical, in the absence of any positive effect in terms of solving socio-economic and infrastructural problems, will inevitably lead to other hard to reverse, negative results both for local government institutions and the system of public authority as a whole. The normal functioning of local government requires, however, not only the presence of its sufficient institutional and functional autonomy from the state, but also an adequate territorial and social base for its implementation. To ensure the formation of viable territorial collectives, especially in urban areas, it seems appropriate to promote the development of self-government based on local groups at the intra-municipal level. Such local groups can independently manage issues of local importance on a small scale (landscaping, social volunteering, and neighborly mutual assistance), and provide, within the boundaries of a local territory, due civil control over the maintenance by municipal authorities of more complex and large-scale local issues (repair and development of infrastructure, removal of solid household waste and more). At the same time, the development of local communities can by no means be a self-sufficient and substitutional mechanism, whose introduction would end the need for democracy in the full scope of municipal structures overall. In this regard, the experience of local communities’ development in Germany, a state with legal traditions similar to Russian ones, with a centuries-old history of the development of territorial communities and a difficult path to building democracy and forming civil society, seems to be very interesting. Here, the progressive development of local forms of democracy and the participation of residents in local issue management are combined with stable mechanisms of municipal government, and the interaction of municipalities with the state does not torpedo the existing citizen forms of self-government. At the same time, the experience of Germany shows that the decentralization of public issue management which involves the local population can only be effective in a situation where, in addition to maintaining a full-fledged self-government mechanism at the general municipal level, relevant local communities are endowed with real competence and resources to influence local issue decision-making. The role of formalized local communities in urban areas, as the German experience shows, can not only facilitate the decentralization of solving public problems, but can also help in timely elimination of triggers for mobilizing citywide supercollectives with negative agendas. This experience seems useful and applicable in the Russian context.

Control of chironomid midge larvae in wastewater stabilisation ponds: comparison of five compounds

2005 ◽  
Vol 51 (12) ◽  
pp. 191-199 ◽  
Author(s):  
R. Craggs ◽  
L. Golding ◽  
S. Clearwater ◽  
L. Susarla ◽  
W. Donovan
Keyword(s):  
New Zealand ◽  
Bacillus Thuringiensis ◽  
Urban Areas ◽  
Large Scale ◽  
Adult Emergence ◽  
Small Scale ◽  
Slight Reduction ◽  
Organic Loading ◽  
Valuable Component ◽  
Pre Treatment

Chironomid midge larvae are a valuable component of wastewater stabilisation pond (WSP) ecology. However, in high numbers, adult midge swarms can be a nuisance to near-by urban areas. Improving WSP treatment by incorporating aerobic or maturation ponds or by the addition of pre-treatment to reduce organic loading also increases the availability of aerobic sediment (midge larva habitat) in the pond system and the potential for midge nuisance problems. The efficacy of Maldison, an organophosphate traditionally used to control midge larvae in New Zealand WSPs, was compared to Bacillus thuringiensis var. israelensis (Bti), Methoprene, Pyriproxyfen and Diflubenzuron which are all more specific to insects and have fewer adverse environmental effects. Initial laboratory trials established the concentration of each compound required to achieve 95% control of the midge population. During 21-day small-scale trials within the WSP, Bti, Diflubenzuron and Maldison reduced live larvae numbers substantially (80–89%) compared to controls and adult midge emergence was markedly reduced by all compounds (72–96%). Large-scale trials with Bti (Vectobac® WG) powder (1000 μg/L) only caused a slight reduction in midge larvae numbers compared to controls and had little effect on adult emergence, however, Methoprene (Prolink XRG granules) (50 μgAI/L) reduced midge adult emergence by ∼80% over 25 days and has been used successfully to control several midge nuisance outbreaks.

Thermo-Economic Optimization in the Design of Small-Scale and Residential Cogeneration Systems

2009 ◽  
Author(s):  
C. P. Lea˜o ◽  
S. F. C. F. Teixeira ◽  
A. M. Silva ◽  
M. L. Nunes ◽  
L. A. S. B. Martins
Keyword(s):  
Gas Turbine ◽  
Urban Areas ◽  
Pressure Ratio ◽  
Optimization Method ◽  
Turbine Engines ◽  
Small Scale ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Economic Optimization ◽  
Micro Turbine

In recent years, gas-turbine engines have undergone major improvements both in efficiency and cost reductions. Several inexpensive models are available in the range of 30 to 250 kWe, with electrical efficiencies already approaching 30%, due to the use of a basic air-compressor associated to an internal air pre-heater. Gas-turbine engines offer significant advantages over Diesel or IC engines, particularly when Natural Gas (NG) is used as fuel. With the current market trends toward Distributed Generation (DG) and the increased substitution of boilers by NG-fuelled cogeneration installations for CO2 emissions reduction, small-scale gas turbine units can be the ideal solution for energy systems located in urban areas. A numerical optimization method was applied to a small-scale unit delivering 100 kW of power and 0.86 kg/s of water, heated from 318 to 353K. In this academic study, the unit is based on a micro gas-turbine and includes an internal pre-heater, typical of these low pressure-ratio turbines, and an external heat recovery system. The problem was formulated as a non-linear optimisation model with the minimisation of costs subject to the physical and thermodynamic constraints. Despite difficulties in obtaining data for some of the components cost-equations, the preliminary results indicate that the optimal compressor pressure ratio is about half of the usual values found in large installations, but higher than those of the currently available micro-turbine models, while the turbine inlet temperature remains virtually unchanged.

scholarly journals Mapping the Production and Mobilization Functions of Collective Action

2020 ◽  
Vol 6 ◽  
pp. 237802312097772
Author(s):  
Blaine G. Robbins ◽  
Ross L. Matsueda ◽  
Steven J. Pfaff
Keyword(s):  
Collective Action ◽  
Undergraduate Students ◽  
Social Life ◽  
Common Good ◽  
Latent Class ◽  
Critical Mass ◽  
Population Level ◽  
Individual Heterogeneity ◽  
Average Production ◽  
Intentions To Participate

Collective action is a fundamental feature of human social life. If public goods are to materialize, social norms are to emerge, and social protests are to succeed, individuals must act jointly to achieve their collective ends. But how can collective action evolve when individuals receive the benefits of a common good without contributing to its production? According to theories of the critical mass, the success of collective action hinges on the type of production function required for the provision of a common good. Production functions and mobilization functions, however, have proven difficult to observe empirically in large groups. Here, the authors report results from a factorial survey experiment administered to a disproportionate stratified random sample of undergraduate students ( n = 880) that required respondents to rate their perceptions of and intentions to participate in a hypothetical student protest. Results show that the population-average production and mobilization functions are decelerating, but individual heterogeneity is observed around the population averages. Moreover, the experiment demonstrates that latent class trajectories of production and mobilization functions, rather than population-level consensus or complete individual heterogeneity, exist in the population. The authors show that the majority of latent class trajectories are decelerating, while a minority are linear or relatively constant. The authors find that subjective interest in the common good and attitudes toward protest predict membership in latent class trajectories. Importantly, the authors provide evidence for the predictive validity of their estimates. The authors discuss the implications of these results for theories of the critical mass and for promoting collective action.

scholarly journals Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas – a review

2017 ◽  
Vol 21 (7) ◽  
pp. 3859-3878 ◽  
Author(s):  
Elena Cristiano ◽  
Marie-Claire ten Veldhuis ◽  
Nick van de Giesen
Keyword(s):  
Temporal Variability ◽  
Urban Areas ◽  
Rainfall Variability ◽  
Urban Environments ◽  
Hydrological Processes ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Weather Radars ◽  
New Instruments

Abstract. In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological response, based on small-scale representation of urban catchment spatial variability. Despite these efforts, interactions between rainfall variability, catchment heterogeneity, and hydrological response remain poorly understood. This paper presents a review of our current understanding of hydrological processes in urban environments as reported in the literature, focusing on their spatial and temporal variability aspects. We review recent findings on the effects of rainfall variability on hydrological response and identify gaps where knowledge needs to be further developed to improve our understanding of and capability to predict urban hydrological response.

scholarly journals Wind Micro-Turbine Networks for Urban Areas: Optimal Design and Power Scalability of Permanent Magnet Generators

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2759 ◽  
Author(s):  
Marco Palmieri ◽  
Salvatore Bozzella ◽  
Giuseppe Cascella ◽  
Marco Bronzini ◽  
Marco Torresi ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Urban Areas ◽  
Permanent Magnets ◽  
Design Procedure ◽  
Circuit Board ◽  
Small Scale ◽  
Electrical Machine ◽  
Direct Drive ◽  
Original Design ◽  
Power Capability

This work is focused on the design optimization of electrical machines that are used in small-scale direct-drive aerogenerators. A ducted wind turbine, equipped with a diffuser, is considered due to its enhanced power capability with respect to bare turbines. An annular type Permanent Magnet brushless generator is integrated in the turbine structure: the stator coils are placed in the internal part of the diffuser, whereas the permanent magnets are on an external ring connected to the turbine blade tips. Moreover, as regards the stator windings, the Printed Circuit Board (PCB) technology is investigated in order to exploit its advantages with respect to conventional wire coils, such as the increased current density capacity, the reduction of costs, and the enhanced precision and repeatability of the PCBs. An original design procedure is presented together with some scalability rules. An automated tool has been developed in order to aid the electrical machine designer in the first design stages: the tool performs multi-objective optimizations (using the Matlab Genetic Algorithm Toolbox), coupled to fast Finite Element analysis (through the open-source software FEMM) for the evaluation of the electromagnetic torque and field distribution. The proposed procedure is applied to the design of an annular PM generator directly coupled to a small-scale turbine for an urban application.

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