scholarly journals The Impact of Nonlocal Ammonia on Submicron Particulate Matter and Visibility Degradation in Urban Shanghai

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Roeland Cornelis Jansen ◽  
Jianmin Chen ◽  
Yunjie Hu
Keyword(s):  
Particulate Matter ◽  
Correlation Coefficients ◽  
Visibility Degradation ◽  
Molar Equivalent ◽  
On Line ◽  
Inorganic Aerosol ◽  
Negative Exponential ◽  
The Impact ◽  
Mass Concentrations

To study the role of submicron particulate matter on visibility degradation in Shanghai, mass concentrations of PM1, secondary inorganic aerosol (SIA) in PM1, and SIA precursor gasses were on-line monitored during a 4-week intensive campaign in December 2012. During the campaign, 8 haze periods were identified when on average PM1mass increased to 62.1 ± 25.6 μg/m3compared to 30.7 ± 17.1 μg/m3during clear weather periods. The sum of SIA in PM1increased in mass concentration during the haze from 14.9 ± 7.4 μg/m3during clear periods to 29.7 ± 10.7 μg/m3during the haze periods. Correlation coefficients (R2) of the visibility as function of mass concentrations of SIA species in PM1show negative exponential relations implying the importance of the SIA species in visibility reduction. The important role of ammonia in SIA formation is recognized and demonstrated. Generally, ammonium neutralizes sulfate and nitrate and the molar equivalent ratio of ammonium versus the sum of sulfate and nitrate increases during the haze episodes. Air mass backward trajectories introducing the haze periods show the impact of nonlocal ammonia on visibility degradation in Shanghai.

scholarly journals Impact of wildfires on particulate matter in the Euro-Mediterranean in 2007: sensitivity to the parameterization of emissions in air quality models

2018 ◽  
Author(s):  
Marwa Majdi ◽  
Solene Turquety ◽  
Karine Sartelet ◽  
Carole Legorgeu ◽  
Laurent Menut ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Correlation Coefficients ◽  
World Health ◽  
Fire Emissions ◽  
Fire Plumes ◽  
Emissions Modeling ◽  
Highly Sensitive ◽  
Health Organization ◽  
The Impact

Abstract. This study examines the uncertainties on air quality modeling associated with the integration of wildfire emissions in chemistry-transport models (CTMs). To do so, aerosol concentrations during the summer 2007, which was marked by severe fire episodes in the Euro-Mediterranean region especially in Balkan (20–31 July 2007, 24–30 August 2007) and Greece (24–30 August 2007), are analysed. Through comparisons to observations from surface networks and satellite remote sensing, we evaluate the abilities of two CTMs, Polyphemus/Polair3D and CHIMERE, to simulate the impact of fires on the regional particulate matter (PM) concentrations and optical properties. During the two main fire events, fire emissions may contribute up to 90 % of surface PM2.5 concentrations, with a significant regional impact associated with long-range transport. Good general performances of the models and a clear improvement of PM2.5 and aerosol optical depth (AOD) are shown when fires are taken into account in the models with high correlation coefficients. Two sources of uncertainties are specifically analysed in terms of surface PM concentrations and AOD using sensitivity simulations: secondary organic aerosol (SOA) formation from intermediate and semi-volatile organic compounds (I/S-VOCs) and emissions' injection heights. The analysis highlights that surface PM2.5 concentrations are highly sensitive to injection heights (with a sensitivity that can be as high as 50 % compared to the sensitivity for I/S-VOCs emissions which is lower than 30 %). However, AOD which is vertically integrated is less sensitive to the injection heights (mostly below 20 %), but highly sensitive to I/S-VOCs emissions (with sensitivity that can be as high as 40 %). The maximum dispersion, which quantifies uncertainties related to fire emissions modeling, is up to 75 % for PM2.5 in Balkan and Greece, and varies between 36 and 45 % for AOD above fire regions. The simulated number of daily exceedance of World Health Organization (WHO) recommendations for PM2.5 over the considered region reaches 30 days in regions affected by fires and ∼ 10 days in fire plumes which is slightly underestimated compared to available observations. The maximum dispersion (σ) on this indicator is also large (with σ reaching 15 days), showing the need for better understanding of the transport and evolution of fire plumes in addition to fire emissions.

scholarly journals Prediction of source contributions to urban background PM10 concentrations in European cities: a case study for an episode in December 2016 – Part.1 The country contributions

2019 ◽  
Author(s):  
Matthieu Pommier ◽  
Hilde Fagerli ◽  
Michael Schulz ◽  
Alvaro Valdebenito ◽  
Richard Kranenburg ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Total Concentration ◽  
Large Fraction ◽  
Correlation Coefficients ◽  
Grid Cell ◽  
Primary Component ◽  
Mitigation Strategies ◽  
Grid Cells ◽  
European Cities ◽  
The Impact

Abstract. A large fraction of the urban population in Europe is exposed to particulate matter levels above the WHO guideline. To make more effective mitigation strategies, it is important to understand the influence on particulate matter (PM) from pollutants emitted in different European nations. In this study, we evaluate a source apportionment forecasting system aimed to assess the domestic and transboundary contributions to PM in major European cities for an episode in December 2016. The system is composed of two models (EMEP/MSC-W rv4.15 and LOTOS-EUROS v2.0) which allows to consider differences in the source attribution. We also compared the PM10 concentrations and both models present satisfactory agreement in the 4day-forecasts of the surface concentrations, since the hourly concentrations can be highly correlated with in-situ observations. The correlation coefficients reach values up to 0.58 for LOTOS-EUROS and 0.50 for EMEP for the urban stations; and 0.58 for LOTOS-EUROS and 0.72 for EMEP for the rural stations. However, the models under-predict the highest hourly concentrations measured by the urban stations (mean underestimation by 36 %), predictable with the relatively coarse model resolution used (0.25° longitude × 0.125° latitude). For the source receptor calculations, the EMEP/MSC-W model uses a scenario having reduced anthropogenic emissions and then it is compared to a reference run where no changes are applied. Different percentages (5 %, 15 % and 50 %) in the reduced emissions were used to test the robustness of the methodology. The impact of the different ways to define the urban area for the studied cities was also investigated (i.e. 1 model grid cell, 9 grid cells and the grid cells covering the definition given by the Global Administrative Area – GADM). We found that by combining the use of the 15 % factor and of a larger domain for the city edges (9 grid cells or GADM), it helps to reduce the impact of non-linearity on the chemistry which is seen in the mismatch between the total concentration and the sum of the concentrations from different calculated sources. Even limited, this non-linearity is observed in the NO3−, NH4+ and H2O concentrations, which is related to gas-aerosol partitioning of the species. The use of a 15 % factor and of a larger city domain also gives a better agreement in the determination of the main country contributors between both country source receptor calculations. During the studied episode, dominated by the influence of the domestic emissions for the 34 European cities investigated and occurring from December 01st to 09th 2016, the two models agree 68 % of the time (on hourly resolution) on the country, having been the dominant contributor to PM10 concentrations. 75 % of the hourly predicted PM10 concentrations by both models, have the same top 5 main country contributors. Better results are found in the determination the dominant country contributor for the primary component (70 % for POM and 80 % for EC) than for the secondary inorganic aerosols (50 %).

scholarly journals The development and outcomes of the COVID-19 disease correlate with the type of nutrition

2021 ◽  
Author(s):  
Sophia Ponomarenko
Keyword(s):  
Correlation Coefficients ◽  
Animal Origin ◽  
The Internet ◽  
Scientific Publications ◽  
Nutritional Factors ◽  
Excessive Consumption ◽  
The Media ◽  
The Impact ◽  
The Relationship

Aim. Analyze the role of diet in the process of infection with the SARS-CoV-2 coronavirus and identify factors that correlate with a decrease in the pathogenic consequences of the COVID-19 disease. Materials and methods. The information and data required for this review were found in scientific publications and the media available on the Internet, as well as obtained from statistical databases using specific keywords, both for a single tag, and in various combinations of them. Statistical samples were managed from sources and facts available on the Internet. Results and discussion. The relationship between nutritional factors and the impact of the 15-month COVID-19 pandemic in different regions was investigated using various available statistics for five continents and 47 countries. A clear relationship was found between the prevalence of the SARS-CoV-2 epidemic and the amount of food consumed, with correlations in the negative range r = -0.98 and r = -0.66 for plant proteins and with a correlation coefficient r = 0.92 for animal proteins. Also, excessive sugar consumption increases the severity of COVID-19 with correlation coefficients in the range of r = 0.99-0.72. Conclusions. Quantitative analysis of statistical data and an assessment of nutritional factors during the development of a 15-month pandemic in various regions showed that the severity of the infectious process of the SARS-CoV-2 virus and the COVID-19 disease was aggravated by excessive consumption of sugar, fat and total protein. The number of people infected with the virus or deaths from COVID-19 per 100,000 inhabitants was radically lower in regions where more plant foods were consumed than products of animal origin.

The relationship between leadership style and the success of Lean management implementation

2018 ◽  
Vol 39 (6) ◽  
pp. 807-824 ◽  
Author(s):  
Daniela Maria da Costa Nogueira ◽  
Paulo S.A. Sousa ◽  
Maria R.A. Moreira
Keyword(s):  
Leadership Style ◽  
Positive Impact ◽  
Intellectual Stimulation ◽  
Lean Management ◽  
Empowering Leadership ◽  
Content Type ◽  
On Line ◽  
The Impact ◽  
The Relationship

Purpose The purpose of this paper is to better understand the role that leadership plays in the success of Lean management (LM) implementation, by trying to identify what is the impact of the transactional, transformational, directive and empowering leadership styles on the success of such an implementation in Portuguese companies, and what are the most important leaders’ attributes. Design/methodology/approach An on-line questionnaire was distributed to 65 manufacturing and services Portuguese organizations that have implemented LM. Findings The results suggest that the empowering leadership style has a positive impact on the success of LM implementation. Even though results do not allow concluding about the impact of the other styles, several leader’s attributes were identified as having influence: individualized consideration, information sharing, skill development, intellectual stimulation, assigned goals and self-directed decision making. Originality/value Very few studies have addressed the role of leadership in the success of adopting LM and, to the best knowledge, only one paper studied the critical attributes of leaders in LM implementation. Moreover, the present study focuses in Portugal, country where this topic has rarely been investigated.

scholarly journals Rarity of microbial species: In search of reliable associations

2018 ◽  
Author(s):  
Arnaud Cougoul ◽  
Xavier Bailly ◽  
Gwenaëel Vourc’h ◽  
Patrick Gasqui
Keyword(s):  
Correlation Coefficients ◽  
Computation Time ◽  
Microbial Interactions ◽  
Operational Taxonomic Units ◽  
Abundance Data ◽  
The Impact ◽  
Empirical Approaches ◽  
Read Abundance ◽  
Methodological Difficulties

AbstractThe role of microbial interactions on the properties of microbiota is a topic of key interest in microbial ecology. Microbiota contain hundreds to thousands of operational taxonomic units (OTUs), most of which are rare. This feature of community structure can lead to methodological difficulties: simulations have shown that methods for detecting pairwise associations between OTUs (which presumably reflect interactions) yield problematic results. The performance of association detection tools is impaired for a high proportion of zeros in OTU table. Here, we explored the statistical testability of such associations given occurrence and read abundance data. The goal was to understand the impact of OTU rarity on the testability of correlation coefficients. We found that a large proportion of pairwise associations, especially negative associations, cannot be reliably tested. This constraint could hamper the identification of candidate biological agents that could be used to control rare pathogens. Consequently, identifying testable associations could serve as an objective method for trimming datasets (in lieu of current empirical approaches). This trimming strategy could significantly reduce the computation time and improve inference of association networks. When OTU prevalence is low, association measures for occurrence and read abundance data are correlated, raising questions about the information actually being captured.

scholarly journals The development of infants’ responses to mispronunciations: A Meta-Analysis

2019 ◽  
Author(s):  
Katie Von Holzen ◽  
Christina Bergmann
Keyword(s):  
Sentence Processing ◽  
Native Language ◽  
Meta Analysis ◽  
Vocabulary Size ◽  
Phonological Representations ◽  
On Line ◽  
The Impact ◽  
Line P ◽  
Made In

As they develop into mature speakers of their native language, infants must not only learn words but also the sounds that make up those words. To do so, they must strike a balance between accepting speaker dependent variation (e.g. mood, voice, accent), but appropriately rejecting variation when it (potentially) changes a word's meaning (e.g. cat vs. hat). This meta-analysis focuses on studies investigating infants' ability to detect mispronunciations in familiar words, or mispronunciation sensitivity. Our goal was to evaluate the development of infants' phonological representations for familiar words as well as explore the role of experimental manipulations related to theoretical questions and analysis choices. The results show that although infants are sensitive to mispronunciations, they still accept these altered forms as labels for target objects. Interestingly, this ability is not modulated by age or vocabulary size, suggesting that a mature understanding of native language phonology may be present in infants from an early age, possibly before the vocabulary explosion. These results also support several theoretical assumptions made in the literature, such as sensitivity to mispronunciation size and position of the mispronunciation. We also shed light on the impact of data analysis choices that may lead to different conclusions regarding the development of infants' mispronunciation sensitivity. Our paper concludes with recommendations for improved practice in testing infants' word and sentence processing on-line.

scholarly journals Changes in particulate matter physical properties during Saharan advections over Rome (Italy): a four-year study, 2001–2004

2013 ◽  
Vol 13 (2) ◽  
pp. 4963-4988 ◽  
Author(s):  
G. P. Gobbi ◽  
F. Angelini ◽  
F. Barnaba ◽  
F. Costabile ◽  
J. M. Baldasano ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Physical Properties ◽  
Saharan Dust ◽  
Centre Of Mass ◽  
Central Mediterranean ◽  
Regional Background ◽  
The Impact ◽  
The City ◽  
Mass Concentrations

Abstract. Particulate matter mass concentrations measured in the city of Rome (Italy) in the period 2001–2004 have been cross-analysed with concurrent Saharan dust advection events to infer the impact these natural episodes bear on the standard air quality parameter PM10 observed at two city stations and at one regional background station. Natural events as Saharan dust advections are associated to a definite health risk. At the same time, the Directive 2008/50/EC allows subtraction of PM exceedances caused by natural contributions from statistics used to determine air-quality of EU sites. In this respect, it is important to detect and characterize such advections by means of reliable, operational techniques. To assess the PM10 increase we used both the "regional-background method" suggested by EC Guidelines and a "local background" one, demonstrated to be most suited to this central Mediterranean region. The two approaches provided results within 20% from each other. The sequence of Saharan advections over the city has been either detected by Polarization Lidar (laser radar) observations or forecast by the operational numerical regional mineral dust model BSC-DREAM8b of the Barcelona Supercomputing Centre. Lidar observations were also employed to retrieve the average physical properties of the dust clouds as a function of height. Along the four-year period, Lidar measurements (703 evenly distributed days) revealed Saharan plumes transits over Rome on 28.6% of the days, with minimum occurrence in wintertime. Dust was observed to reach the ground on 17.5% of the days totalling 88 episodes. Most (90%) of these advections lasted up to 5 days, averaging to ~3 days. Median time lag between advections was 7 days. Typical altitude range of the dust plumes was 0–6 km, with centre of mass at ~3 km a.g.l. BSC-DREAM8b model simulations (1461 days) predicted Lidar detectable (532nm extinction coefficient >0.005 km−1) dust advections on 25.9% of the days, with ground contacts on 13% of the days. As in the Lidar case, the average dust centre of mass was forecast at ~3 km. Along the 703-day Lidar dataset, model forecast and Lidar detection of the presence of dust coincided on 80% of the cases, 92% coincidences are found within a ±1-day window. Combination of the BSC-DREAM8b and Lidar records leads to about 21% of the days being affected by presence of Saharan dust at the ground. This combined dataset has been used to compute the increase in PM with respect to dust-unaffected previous days. This analysis has shown Saharan dust events to exert a meaningful impact on the PM10 records, causing average increases of the order of 11.9 μg m−3. Conversely, PM10 increases computed relying only on the Lidar detections (i.e., presence of dust layers actually observed) were of the order of 15.6 μg m−3. Both analyses indicate the annual average contribution of dust advections to the city PM10 mass concentrations to be of the order of 2.35 μg m−3. These results confirm Saharan advections in the central Mediterranean as important modulators of PM10 loads and exceedances.

scholarly journals Research on the Advantages of Digital Sensor Equipment in Language Audio-Visual and Oral Teaching

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wu Yufei ◽  
Wang Dandan ◽  
Zhu Yanwei
Keyword(s):  
Impulse Response Function ◽  
Auditory Attention ◽  
Sensor Technology ◽  
Accurate Information ◽  
Auditory Information ◽  
Speech Time ◽  
On Line ◽  
The Impact ◽  
Oral Teaching

Digital sensors use biotechnology and information processing technology to strengthen the processing of relevant visual and auditory information, which is helpful to ensure that the receiver can obtain more accurate information, so as to improve the learning effect and reduce the impact on the environment. This paper designs an experiment to explore the role of digital sensors in language audio-visual teaching, which provides a reference for the application of digital sensors in the future. The impulse response function in sensor technology is introduced. The speech time domain envelope and time-varying mouth area of the sensor device are calculated. The auditory attention transfer detection based on line of sight rotation estimation is carried out through the auditory attention decoding fusion technology and the sensor auditory attention conversion detection method. At the same time, the characteristic of sensor heog signal is analyzed. The results show that the algorithm proposed in this paper has good results.

scholarly journals Be Muslim Buy from Muslims: Impact of Retailers Religious Orientations on Consumers Purchasing Patterns

2021 ◽  
Vol 7 (4) ◽  
Author(s):  
Saba Amin ◽  
Muhammad Nabeel Safdar ◽  
Qamar Ali
Keyword(s):  
Positive Impact ◽  
Religious Affiliation ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Purchase Intentions ◽  
Mediating Role ◽  
Extrinsic Religiosity ◽  
Purchasing Patterns ◽  
The Impact

Purpose: This study investigates the impact of retailers’ religious affiliation and religiosity on consumers’ purchasing patterns. The moderated mediation model of this study contemplates a) the mediating role of buying motives of consumers based on thoughts, feelings, emotions, which help them make decisions, and b) the moderating role of intrinsic and extrinsic religiosity dimensions. Design/Methodology/Approach: Data were obtained from consumers from metropolitan cities of Pakistan. Simple Linear Regression and Pearson Correlation Coefficients were used to investigate the relationships with the help of SPSS and AMOS software. ArcMap was used to represent the selected sample size. Findings: Drawing on the belief-congruence theory, the findings of this study suggest that religious affiliation of the retailer (RAR) has a significantly positive impact on consumer purchase intentions (CPI) and that consumer buying motives (CBM) have a strong mediating role between RAR and CPI. The study also reveals that the impact of CBM on CPI is stronger in consumers with high intrinsic religiosity. However, data analysis shows that consumers’ extrinsic religiosity is not a significant moderator of the relationship between consumers’ buying motives and purchase intentions. Implications/Originality/Value: The findings of this study can help retailers make better policies to attract consumers and sustain their businesses.                                                           

The Role of Uncertainty Analysis in Model Validation

2003 ◽  
Author(s):  
Richard G. Hills ◽  
Ian H. Leslie
Keyword(s):  
Uncertainty Analysis ◽  
Model Validation ◽  
Correlation Coefficients ◽  
Physical Processes ◽  
Graph Norm ◽  
Thermally Induced ◽  
Test Models ◽  
Model Predictions ◽  
The Impact

Our increased dependence on mathematical models for engineering design, coupled with our decreased dependence on experimental observation, leads to the obvious question — how do we know that our models are valid representations of physical processes? We test models by comparisons between model predictions and experimental observations. As our models become more complex (i.e., multiphysics models), our ability to test models over the range of possible applications becomes more difficult. This difficulty is compounded by the uncertainty that is invariably present in the experimental data used to test the model, the uncertainties in the parameters that are incorporated into the model, and the uncertainties in the model structure itself. When significant uncertainties of these types are present, evaluating model validity through graphical comparisons of model predictions to experimental observations becomes very subjective. Here we consider the impact of uncertainty and the role of uncertainty analysis in model validation. We focus on uncertainty in the model predictions due to parameter uncertainty, and on experimental uncertainty due to measurement noise. We show that characterizing these uncertainties allows us to use a meaningful metric for model testing that is less subjective than the traditional “view graph norm” or the evaluation of correlation coefficients. We demonstrate this methodology through its application to a model and experimental observations of thermally induced foam decomposition.

Sign in / Sign up

Export Citation Format

Share Document