scholarly journals Assessing representativity of NH<sub>3</sub> measurements influenced by boundary-layer dynamics and turbulent dispersion of a nearby emission source

2021 ◽  
Author(s):  
Ruben B. Schulte ◽  
Margreet C. van Zanten ◽  
Jordi Vilà-Guerau de Arellano
Keyword(s):  
Molar Fraction ◽  
Flux Measurement ◽  
Emission Source ◽  
Turbulent Dispersion ◽  
Emission Sources ◽  
Plume Dispersion ◽  
Fine Scale ◽  
Simulation Framework ◽  
Local Conditions ◽  
The Impact

Abstract. This study presents a fine scale simulation approach to assess the representativity of ammonia (NH3) measurements in proximity of an emission source. Close proximity to emission sources (< 5 km) can introduce a bias in regionally representative measurements of the NH3 molar fraction and flux. Measurement sites should therefore be located a significant distance from emission sources, but such requirements are poorly defined and can be difficult to meet in densely agricultural regions. This study presents a consistent criterium to assess the regional representativity of NH3 measurements in proximity of an emission source, calculating variables that quantify the NH3 plume dispersion using a series of numerical experiments at a fine resolution (20 m). Our fine scale simulation framework with explicitly resolved turbulence enables us to distinguish between the background NH3 and the emission plume, including realistic representations of NH3 deposition and chemical gas-aerosol transformations. We introduce the concept of blending-distance, based on the calculation of turbulent fluctuations, to systematically analyze the impact of the emission plume on simulated measurements, relative to this background NH3. This sensitivity analysis includes systematic experiments varying meteorological factors, emission/deposition and NH3 dependences. Considering these sensitivities, we find that NH3 measurements should be located at a minimum distance of 0.5–2.5 km and 1–3.5 km from an emission source, for NH3 molar fraction and flux measurements respectively. The simulation framework presented here can easily be adapted to local conditions and paves the way for future ammonia research at high spatio-temporal resolution.

The Impact of High-Speed Rail on the Spatial Structure of Chinese Urban Agglomerations

2020 ◽  
Vol 46 (3) ◽  
pp. 379-397
Author(s):  
Chunyang Wang
Keyword(s):  
High Speed ◽  
River Delta ◽  
City Size ◽  
High Speed Rail ◽  
Local Conditions ◽  
Urban Agglomerations ◽  
Large Cities ◽  
Spatial Systems ◽  
Economic Concentration ◽  
The Impact

This paper measures the spatial evolution of urban agglomerations to understand be er the impact of high-speed rail (HSR) construction, based on panel data from fi ve major urban agglomerations in China for the period 2004–2015. It is found that there are signi ficant regional diff erences of HSR impacts. The construction of HSR has promoted population and economic diff usion in two advanced urban agglomerations, namely the Yang e River Delta and Pearl River Delta, while promoting population and economic concentration in two relatively less advanced urban agglomerations, e.g. the middle reaches of the Yang e River and Chengdu–Chongqing. In terms of city size, HSR promotes the economic proliferation of large cities and the economic concentration of small and medium-sized cities along its routes. HSR networking has provided a new impetus for restructuring urban spatial systems. Every region should optimize the industrial division with strategic functions of urban agglomeration according to local conditions and accelerate the construction of inter-city intra-regional transport network to maximize the eff ects of high-speed rail across a large regional territory.

scholarly journals Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

2021 ◽  
Author(s):  
Francesco Mancini ◽  
Raffaele De Giorgi ◽  
Alessandro Ludovisi ◽  
Salvatrice Vizzini ◽  
Giorgio Mancinelli
Keyword(s):  
Dietary Habits ◽  
Trophic Position ◽  
Ecological Impact ◽  
Central Italy ◽  
Local Conditions ◽  
Dikerogammarus Villosus ◽  
Isotopic Signatures ◽  
Depth Analysis ◽  
Stable Isotope Study ◽  
The Impact

AbstractThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.

scholarly journals The Environmental Effects of the April 2020 Wildfires and the Cs-137 Re-Suspension in the Chernobyl Exclusion Zone: A Multi-Hazard Threat

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 467
Author(s):  
Rocío Baró ◽  
Christian Maurer ◽  
Jerome Brioude ◽  
Delia Arnold ◽  
Marcus Hirtl
Keyword(s):  
Air Quality ◽  
Nuclear Power ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Point Of View ◽  
Plume Dispersion ◽  
Exclusion Zone ◽  
Fire Plume ◽  
Mean Values ◽  
The Impact

This paper demonstrates the environmental impacts of the wildfires occurring at the beginning of April 2020 in and around the highly contaminated Chernobyl Exclusion Zone (CEZ). Due to the critical fire location, concerns arose about secondary radioactive contamination potentially spreading over Europe. The impact of the fire was assessed through the evaluation of fire plume dispersion and re-suspension of the radionuclide Cs-137, whereas, to assess the smoke plume effect, a WRF-Chem simulation was performed and compared to Tropospheric Monitoring Instrument (TROPOMI) satellite columns. The results show agreement of the simulated black carbon and carbon monoxide plumes with the plumes as observed by TROPOMI, where pollutants were also transported to Belarus. From an air quality and health perspective, the wildfires caused extremely bad air quality over Kiev, where the WRF-Chem model simulated mean values of PM2.5 up to 300 µg/m3 (during the first fire outbreak) over CEZ. The re-suspension of Cs-137 was assessed by a Bayesian inverse modelling approach using FLEXPART as the atmospheric transport model and Ukraine observations, yielding a total release of 600 ± 200 GBq. The increase in both smoke and Cs-137 emissions was only well correlated on the 9 April, likely related to a shift of the focus area of the fires. From a radiological point of view even the highest Cs-137 values (average measured or modelled air concentrations and modelled deposition) at the measurement site closest to the Chernobyl Nuclear Power Plant, i.e., Kiev, posed no health risk.

scholarly journals How far from the road should land cover be assessed? A case study on mesopredator mortality on roads

2021 ◽  
Vol 67 (2) ◽  
Author(s):  
Angelika Nieszała ◽  
Daniel Klich
Keyword(s):  
Land Cover ◽  
Red Fox ◽  
Home Range Size ◽  
Buffer Size ◽  
Local Conditions ◽  
Explanatory Variables ◽  
The Road ◽  
Spatially Correlated ◽  
European Badger ◽  
The Impact

AbstractThe methods used to assess the significance of land cover in the vicinity of a road for the mortality of mesopredators are diverse. In assessing the effect of land cover along the road on road causalities, scientists use various buffer sizes, or even no buffer along the road. The aim of this study was to verify how results of land cover effects on the mortality of mesopredators on roads may differ when analyzing various buffer sizes from the road. We assessed road causalities in the Warmian-Masurian voivodeship (Poland) from 3 consecutive years: 2015, 2016, and 2017. The roads were divided into equal sections of 2000 m each with buffer size of radius: 10, 250, 500, and 1000 m. We analyzed the number of road kills of red fox and European badger separately in a generalized linear model, whereas explanatory variables we used land cover types (based on the Corine Land Cover inventory) and traffic volume. Mean annual mortality from road collisions amounts to 2.36% of the red fox population and 3.82% of the European badger population. We found that the buffer size determines the results of the impact of land cover on mesocarnivore mortality on roads. The red fox differed from the European badger in response to land cover depending on the buffer size. The differences we have shown relate in particular to built-up areas. Our results indicate a 500-m buffer as best reflecting the land cover effects in road kills of both species. This was confirmed by model evaluation and a tendency to use or avoid the vicinity of human settlements of the analyzed species. We concluded that buffer size will probably affect mostly the significance of cover types that are spatially correlated with roads, positively or negatively. We suggest that the home range size of given species in local conditions should be assessed before determining the size of the buffer for analysis.

scholarly journals A flexible ChIP-sequencing simulation toolkit

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
An Zheng ◽  
Michael Lamkin ◽  
Yutong Qiu ◽  
Kevin Ren ◽  
Alon Goren ◽  
...  
Keyword(s):  
Ground Truth ◽  
Peak Calling ◽  
Simulation Framework ◽  
Experimental Conditions ◽  
Ground Truth Data ◽  
Chip Sequencing ◽  
Genome Wide ◽  
Experimental Parameters ◽  
Differential Binding ◽  
The Impact

Abstract Background A major challenge in evaluating quantitative ChIP-seq analyses, such as peak calling and differential binding, is a lack of reliable ground truth data. Accurate simulation of ChIP-seq data can mitigate this challenge, but existing frameworks are either too cumbersome to apply genome-wide or unable to model a number of important experimental conditions in ChIP-seq. Results We present ChIPs, a toolkit for rapidly simulating ChIP-seq data using statistical models of key experimental steps. We demonstrate how ChIPs can be used for a range of applications, including benchmarking analysis tools and evaluating the impact of various experimental parameters. ChIPs is implemented as a standalone command-line program written in C++ and is available from https://github.com/gymreklab/chips. Conclusions ChIPs is an efficient ChIP-seq simulation framework that generates realistic datasets over a flexible range of experimental conditions. It can serve as an important component in various ChIP-seq analyses where ground truth data are needed.

DEATH AND THE MODERN EMPIRE: THE 1918–19 INFLUENZA EPIDEMIC IN INDIA

2019 ◽  
Vol 29 ◽  
pp. 181-200
Author(s):  
David Arnold
Keyword(s):  
Influenza Pandemic ◽  
Influenza Epidemic ◽  
Local Conditions ◽  
Military Recruitment ◽  
Visual Evidence ◽  
Private Correspondence ◽  
Political Unrest ◽  
Food Shortages ◽  
The Impact ◽  
The Great War

ABSTRACTIn India the 1918–19 influenza pandemic cost at least twelve million lives, more than in any other country; it caused widespread suffering and disrupted the economy and infrastructure. Yet, despite this, and in contrast to the growing literature on recovering the ‘forgotten’ pandemic in other countries, remarkably little was recorded about the epidemic in India at the time or has appeared in the subsequent historiography. An absence of visual evidence is indicative of a more general paucity of contemporary material and first-hand testimony. In seeking to explain this absence, it is argued that, while India was exposed to influenza as a global event and to the effects of its involvement in the Great War, the influenza episode needs to be more fully understood in terms of local conditions. The impact of the disease was overshadowed by the prior encounter with bubonic plague, by military recruitment and the war, and by food shortages and price rises that pushed India to the brink of famine. Subsumed within a dominant narrative of political unrest and economic discontent, the epidemic found scant expression in official documentation, public debate and/or even private correspondence.

scholarly journals Identification of the degree of impact of dams on the hydrologic regime of semi-arid rivers: an evaluation of the DHRAM method

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Naiah Caroline Rodrigues de Souza ◽  
◽  
Andrea Sousa Fontes ◽  
Lafayette Dantas da Luz ◽  
Sandra Maria Conceição Pinheiro ◽  
...  
Keyword(s):  
Hydrological Regime ◽  
Flow Regulation ◽  
Hydrologic Regime ◽  
Local Conditions ◽  
Operating Rules ◽  
Hydrologic Variability ◽  
High Degree ◽  
The Impact ◽  
Semi Arid

ABSTRACT The flow regulation that results from the implantation of dams causes consequences to the river ecosystems due to the modification on the characteristics of the hydrologic regime. The investigation of these changes become relevant, mainly in semi-arid regions where there is a great amount of these hydraulic structures and lack of such analyzes. Considering the above, this paper aims to evaluate the Dundee Hydrological Regime Alteration Method (DHRAM) through the classification of the degree of impact of dams located on rivers Itapicuru, Paraguaçu and their tributaries, verifying the adequacy of its use to represent the semi-arid hydrologic regime. Thereby, the DHRAM was applied in three versions: considering the thresholds that define the scores to classify the degree of impact in its original set (accordingly to Black et al. (2005)); with the adjustment of those thresholds to local conditions; and, with the regrouping of variables and adjustment of thresholds. The results showed that the method in its original set is applicable to semi-arid rivers, however it tends to be very restrictive against the high natural hydrologic variability characteristic of these rivers, and it ends up pointing to a high degree of alteration for dams that are known for not causing a very siginifcant flow regulation. The DHRAM with the regrouping of variables and the adjustment of thresholds presented the classification that approached the most to the known characteristics of the studied dams, being useful for the evaluation of the impact of dams still in project, and also to guide the adoption of operating rules that minimize the most significant hydrologic alterations that are identified.

Revealing of the specificity of mortgage housing lending based on the results of clustering of regions

2021 ◽  
Vol 27 (12) ◽  
pp. 2679-2697
Author(s):  
Lyudmila E. ROMANOVA ◽  
Anna L. SABININA ◽  
Andrei I. CHUKANOV ◽  
Dar’ya M. KORSHUNOVA
Keyword(s):  
Systems Approach ◽  
Mortgage Lending ◽  
Effective Algorithm ◽  
Russian Regions ◽  
Local Conditions ◽  
Partitioning Around Medoids ◽  
Analysis And Synthesis ◽  
The Russian Federation ◽  
The Impact ◽  
Regions Of Russia

Subject. This article deals with the particularities of the development of housing mortgage lending in the regions of Russia. Objectives. The article aims to substantiate the need for clustering of territorial entities by level of development of mortgage housing lending in Russia and test the most effective algorithm for mortgage clustering of regions. Methods. For the study, we used a systems approach, including scientific abstraction, analysis and synthesis, and statistical methods of data analysis. The algorithm k-medoids – Partitioning Around Medoids (PAM) was also used. Results. Based on the results of the study of regional statistics of the Russian Federation, the article reveals a significant asymmetry in the values of key socioeconomic indices that determine the level and dynamics of housing mortgages in the regions. This necessitates the clustering of territorial entities according to the level of development of mortgage housing lending in the country. To take into account the impact of various local conditions in assessing the prospects for the development of regional housing mortgages, the article proposes an indicator, namely, the integral regional mortgage affordability index. On its basis, in accordance with the selected clustering procedure, the article identifies five mortgage clusters in Russia and identifies their representative regions. Conclusions. Based on the analysis of the specificity of the development of regional mortgages in the Tula Oblast, taking into account the implementation of the target State programme, the article concludes that it is necessary to improve the mechanisms for financing regional mortgage programmes and justifies the need to develop differentiated programmes for the development of housing mortgages in groups of Russian regions.

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