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 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 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.

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.

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.                                                                                                                 

scholarly journals THE IMPACT OF THE COVID-19 PANDEMIC AND THE DROUGHT ON THE PRICES OF THE MAIN AGRICULTURAL PRODUCTS OF ANIMAL ORIGIN IN ROMANIA

2020 ◽  
pp. 108-118
Keyword(s):  
Price Level ◽  
Correlation Coefficients ◽  
Point Of View ◽  
Agricultural Products ◽  
Animal Origin ◽  
Market Demand ◽  
Statistical Point ◽  
The World ◽  
The Impact

Globally, the pandemic installed by the coronavirus has led to a change in the way business is conducted. In the context of the economic crisis knocking on the door, the states of the world are trying to take the most severe measures to mitigate the effects of this epidemic. One sector of the economy that needs to be protected is agriculture, because it provides the much-needed food for everyone. The role of farmers is very important in this equation, as they provide the necessary food stabilizing stocks of food that can be depleted faster. In this paper we want to determine the possible impact that the drought and the overlap of the COVID pandemic on it may have on the prices of agricultural products of animal origin in Romania. In this context, the level of prices in the first half of the previous year was compared with the level of prices in the first half of the current year, in order to be able to determine, from a statistical point of view, whether there are significant differences. It was found that for five of the six products analyzed, the prices in the first half of 2020 were higher than in the first half of 2019. Following this analysis, the correlation coefficients between the price level and the precipitation level were determined, and subsequently between the price level and the market demand, the latter influenced by the pandemic. It was found that both phenomena indirectly influenced the prices of agricultural products of animal origin.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Intergroup Threat and Outgroup Attitudes

2013 ◽  
Vol 44 (5) ◽  
pp. 311-319 ◽  
Author(s):  
Marco Brambilla ◽  
David A. Butz
Keyword(s):  
Gay Men ◽  
Social Group ◽  
Welfare Recipients ◽  
Intergroup Attitudes ◽  
Social Policies ◽  
Intergroup Threat ◽  
Economic Threat ◽  
The Impact ◽  
General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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