scholarly journals Estimation of the Pb Content in a Tailings Dam Using a Linear Regression Model Based on the Chargeability and Resistivity Values of the Wastes (La Carolina Mining District, Spain)

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 7
Author(s):  
Rosendo Mendoza ◽  
Julián Martínez ◽  
Maria Carmen Hidalgo ◽  
Maria José Campos-Suñol
Keyword(s):  
Linear Regression ◽  
Contaminated Soils ◽  
Mining District ◽  
Mine Wastes ◽  
Multivariate Statistical ◽  
Flotation Process ◽  
Mean Values ◽  
Geophysical Techniques ◽  
Dispersion Patterns ◽  
High Metal

The study area is located in the old mining district of Linares–La Carolina (southeastern Spain), the largest global producer of lead between 1875 and 1920. The selected environmental liability is the dam of the Federico mine and the waste that was generated during the flotation process. Geophysical techniques were applied along the slope of the dam, specifically ERT and IP. In total, 26 waste samples were taken along the entire slope of the dam, in which a high metal(oid) content was identified, sometimes much higher than the reference levels established by European and regional legislation for contaminated soils. The concentrations of Pb, As, and Ba stood out, with mean values of 4863 mg.kg−1, 89 mg.kg−1, and 794 mg.kg−1, respectively. Univariate and multivariate statistical analysis could characterize the distribution of the contents of the different elements along the slope, defining the associations and dispersion patterns of the metal(oid)s in the interior structure of the mine wastes. With the results of the Pb content (the most abundant metal in mineral paragenesis), a mathematical model was obtained by linear regression that related the variability of this cation with the variation in electrical resistivity and chargeability obtained by geophysical techniques.

scholarly journals Surface and Underground Geomechanical Characterization of an Area Affected by Instability Phenomena in Zaruma Mining Zone (Ecuador)

2021 ◽  
Vol 13 (6) ◽  
pp. 3272
Author(s):  
Paúl Carrión-Mero ◽  
Maribel Aguilar-Aguilar ◽  
Fernando Morante-Carballo ◽  
María José Domínguez-Cuesta ◽  
Cristhian Sánchez-Padilla ◽  
...  
Keyword(s):  
Mass Movement ◽  
Mining Activity ◽  
Mining District ◽  
Mean Values ◽  
Surface Areas ◽  
Definition Of ◽  
Action Measures ◽  
Geomechanical Characterization ◽  
The City

In the last decade, in the mining district of Zaruma-Portovelo, there has been significant land subsidence related to uncontrolled mining activity. The purpose of this work was to carry out a surface and underground geomechanical characterization of a mining sector north of the city of Zaruma that allows the definition of potentially unstable areas susceptible to the mass movement. The methodology used consists of the following stages: (i) compilation of previous studies; (ii) surface and underground characterization of rocky material to establish its susceptibility to mass movement; (iii) interpretation of results; and (iv) proposal of action measures. Among the most relevant results, it stands out that 26.1% of the 23 stations characterized on the surface present conditions that vary from potentially unstable to unstable. In underground galleries, the studied mean values of the 17 stations indicate that the rock has a medium to good quality, representing a medium susceptibility to gallery destabilization. The results obtained for the surface areas (depths up to 50 m, where altered materials predominate) and the underground areas (depths > 50 m, where the alterations are specific) can be used to identify the areas with a more significant potential for instability. For both cases, it has been possible to define specific monitoring, control, and planning actions for sensitive areas.

Optic Nerve Sheath Diameter in Preterm Infants: Suggested Values

Neonatology ◽  
2021 ◽  
Vol 118 (3) ◽  
pp. 297-300
Author(s):  
Molly Rayner ◽  
Tanya Holt ◽  
Sibasis Daspal ◽  
Prosanta Mondal ◽  
Leanne Langford ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Linear Regression ◽  
Preterm Infants ◽  
Gestational Age ◽  
Optic Nerve Sheath Diameter ◽  
Optic Nerve Sheath ◽  
Mean Values ◽  
Nerve Sheath ◽  
Neurologic Sequelae ◽  
Highly Correlated

<b><i>Objective:</i></b> Timely detection of elevated intracranial pressure (ICP) in highrisk preterm infants may be critical to avoid permanent neurologic sequelae. Size of optic nerve sheath diameter (ONSD) is highly correlated with changes in ICP. Normal ultrasonographic ONSD values for preterm infants have been published. This study sought to compare these data with MRI measured OSND and to propose suggested ultrasonographic ONSD values. <b><i>Methods:</i></b> The ONSD in preterm MRIs were retrospectively measured and related to pre-existing ultrasonographic ONSD. Data were stratified for corrected gestational age. Simple linear regression between ONSD mean values and age was modeled for both eyes, and <i>R</i><sup>2</sup> was calculated. Suggested values for ultrasonographic ONSD were ascertained through linear regression and calculated prediction intervals. <b><i>Results:</i></b> ONSD measurements demonstrated <i>R</i><sup>2</sup> values of 0.95 (right ONSD MRI), 0.95 (left ONSD MRI), 0.96 (right ONSD ultrasound), and 0.93 (left ONSD ultrasound). Suggested ONSD values were incremental with corrected gestational age. <b><i>Conclusion:</i></b> ONSD measurements with MRI and ultrasound are similar. The proposed suggested ONSD values may be helpful in clinical situations where ICPs are suspected or known.

scholarly journals Assessment of Occupational Exposure to BTEX in a Petrochemical Plant via Urinary Biomarkers

2021 ◽  
Vol 13 (13) ◽  
pp. 7178
Author(s):  
Višnja Mihajlović ◽  
Nenad Grba ◽  
Jan Suđi ◽  
Diane Eichert ◽  
Smilja Krajinović ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Urinary Biomarkers ◽  
Working Environment ◽  
Passive Samplers ◽  
Control Group ◽  
Petrochemical Plant ◽  
Exposure Limits ◽  
Multivariate Statistical ◽  
Mean Values ◽  
Relative Standard

This work presents the results of the first Serbian monitoring campaign performed to assess the occupational exposure of petrochemical industry workers to benzene (B), toluene (T), ethylbenzene (E), and xylene (X), known collectively as BTEX. The following urinary biomarkers were investigated: phenol, hippuric acid, o-Cresol, p-Cresol, and creatinine. BTEX compounds were collected in 2014 using Casella passive samplers. Multivariate statistical analysis was performed to put in evidence the correlation between the BTEX measured in air and the concentration of urinary biomarkers. While the results indicate an elevated presence of benzene in the air in the working environment studied that surpasses the national and European Occupational Exposure Limits (OEL), the levels of the remaining (TEX) parameters measured were below the OEL. The high relative standard deviations (RSD) for the concentrations of each BTEX compound (68–161 mg m−3) point toward an intensive occupational exposure to BTEX. This was confirmed by relevant urine biomarkers, particularly by the mean values of phenol, which were ten and fourteen times higher than the ones found in the control group (14–12 mg g−1 of creatinine). On average, workers are at a higher risk of developing cancer (6.1 × 10−3), with risk levels exceeding the US EPA limits. Benzene levels should therefore be maintained under tight controls and monitored via proper urinary biomarkers.

Quantitative characterization, classification and reconstruction of oocyst shapes of Eimeria species from cattle

Parasitology ◽  
1998 ◽  
Vol 116 (1) ◽  
pp. 21-28 ◽  
Author(s):  
C. SOMMER
Keyword(s):  
Fourier Transform ◽  
Quantitative Data ◽  
Inverse Fourier Transform ◽  
Morphological Variability ◽  
Eimeria Species ◽  
Equal Weight ◽  
Agglomerative Clustering ◽  
Multivariate Statistical ◽  
Mean Values ◽  
Size And Shape

This study reports on morphological variability of Eimeria species, which may be given either by drawings or as quantitative data. The drawings may be used to facilitate identification by eye of ‘unknown’ Eimeria specimens, whereas quantitative data may serve as a reference set for identification by multivariate statistical techniques. The morphology of 810 Eimeria specimens was defined in binary (b/w) digital images by pixels of their oocyst outline. A Fourier transform of pixel positions yielded size and shape features. To classify coccidia, the quantitative data were employed in an agglomerative clustering by average linkage algorithm with equal weight assigned to size and shape. An inverse Fourier transform served to reconstruct oocyst outlines, i.e. outlines of average shape and size, from mean values of features in resulting clusters. Clusters were subsequently identified based on their average morphology by comparison with drawings of species in an earlier taxonomical work. Five hundred oocyst outlines were simulated for each cluster representing a species, and shape/size variability was presented in contour diagrams. Differences in species shapes, and correspondence in length and width, were seen after reconstruction by inverse Fourier transform and comparison with earlier studies.

Outlier Detection in Linear Regression

2011 ◽  
pp. 510-550 ◽  
Author(s):  
A. A. M. Nurunnabi ◽  
A. H. M. Rahmatullah Imon ◽  
A. B. M. Shawkat Ali ◽  
Mohammed Nasser
Keyword(s):  
Linear Regression ◽  
Least Squares ◽  
Outlier Detection ◽  
Estimation Procedure ◽  
Support Vector ◽  
Parameter Estimates ◽  
Multivariate Statistical ◽  
Data Contamination ◽  
The People ◽  
Computational Simplicity

Regression analysis is one of the most important branches of multivariate statistical techniques. It is widely used in almost every field of research and application in multifactor data, which helps to investigate and to fit an unknown model for quantifying relations among observed variables. Nowadays, it has drawn a large attention to perform the tasks with neural networks, support vector machines, evolutionary algorithms, et cetera. Till today, least squares (LS) is the most popular parameter estimation technique to the practitioners, mainly because of its computational simplicity and underlying optimal properties. It is well-known by now that the method of least squares is a non-resistant fitting process; even a single outlier can spoil the whole estimation procedure. Data contamination by outlier is a practical problem which certainly cannot be avoided. It is very important to be able to detect these outliers. The authors are concerned about the effect outliers have on parameter estimates and on inferences about models and their suitability. In this chapter the authors have made a short discussion of the most well known and efficient outlier detection techniques with numerical demonstrations in linear regression. The chapter will help the people who are interested in exploring and investigating an effective mathematical model. The goal is to make the monograph self-contained maintaining its general accessibility.

scholarly journals Self-Reinforcing Processes Governing Urban Sprawl in Belgium: Evidence over Six Decades

2020 ◽  
Vol 12 (10) ◽  
pp. 4097 ◽  
Author(s):  
Ahmed Mustafa ◽  
Jacques Teller
Keyword(s):  
Linear Regression ◽  
Population Density ◽  
Urban Sprawl ◽  
Urban Dispersion ◽  
Dispersion Degree ◽  
Dispersion Patterns ◽  
Study Country ◽  
Per Capita ◽  
Different Levels ◽  
Over Time

Urban sprawl is widely acknowledged as an environmental and socio-economic challenge worldwide. This study examines urban sprawl in Belgium over six decades from 1950 to 2010. We assume that sprawl is a self-reinforcing process, i.e., sprawl is fueling further sprawl over time. The main objective of this study is to examine this assumption. We measure urban sprawl at four different levels in this study: country, regions, municipalities, and 1-km2 cells. Three sprawl indices are employed: the degree of urban dispersion, degree of urban permeation of the landscape, and built-up land uptake per capita. These three indices consider both the growth of built-up areas and population density to measure the magnitude of sprawl. The drivers of urban sprawl have been analyzed at a 1-km2 level. The examined drivers are previous urban dispersion patterns, distance to urban cores, elevation, and slope degree by means of linear regression. Urban sprawl significantly increased between 1950 and 1980, whereas its increase was more moderate between 1980 and 2010. Urban dispersion and permeation strongly affect the Brussels and Flanders regions. The results show that the increase in the degree of dispersion is locally driven by previous values of dispersion; i.e., it provides an adequate milieu for further dispersion. Therefore, our conclusion is that urban sprawl in Belgium tends to be a self-reinforcing process.

scholarly journals Mercury Speciation and Microbial Transformations in Mine Wastes, Stream Sediments, and Surface Waters at the Almadén Mining District, Spain

2004 ◽  
Vol 38 (16) ◽  
pp. 4285-4292 ◽  
Author(s):  
John E. Gray ◽  
Mark E. Hines ◽  
Pablo L. Higueras ◽  
Isaac Adatto ◽  
Brenda K. Lasorsa
Keyword(s):  
Surface Waters ◽  
Stream Sediments ◽  
Mercury Speciation ◽  
Mining District ◽  
Mine Wastes ◽  
Microbial Transformations

scholarly journals Assessment of Ni Toxicity to Fungi and Bacteria in Oil Tainted Soils in Greater Port Harcourt Area, Nigeria

2021 ◽  
Vol 25 (7) ◽  
pp. 1221-1229
Author(s):  
M.P. Wanjala ◽  
L. Odokuma ◽  
I. Etela ◽  
R. Ramkat ◽  
B.A. Odogwu ◽  
...  
Keyword(s):  
Urban Area ◽  
Contaminated Soils ◽  
Industrial Area ◽  
Agricultural Area ◽  
Natural Ecosystems ◽  
Mean Values ◽  
Mining Areas ◽  
Significant Difference ◽  
The Mean ◽  
Study Sites

Intensified urbanization and industrialization are rapidly triggering the release of pollutants to the environment. This study determined the extent of soil contamination with Nickel (Ni) in oil mining areas and its effect on the levels of Ni tolerance by fungi and bacteria. The total CFUs/g of soil were enumerated after a culture period of 7 days at 28°C and LC50 was determined using probit and regression analysis. The mean values of Ni were 1.38±0.23 in industrial area, 1.41±0.36 ppm in agricultural area and 1.02±0.64 in urban area. The mean values of Total Petroleum Hydrocarbon (TPH) were 4,405.46 ppm in industrial area, 55.65 ppm in agricultural area and 1,304.53 ppm in urban area. Nickel’s peak concentration indicating growth of both fungi and bacteria at 150 ppm. There was significant difference (p ≤ 0.000) in the mean levels of LC50 for fungi among the study sites. There was no significant correlation between the concentration of TPH in soil and LC50 of fungi (r = -0.169) and bacteria (r = 0.042). In conclusion, TPH influenced the levels of fungi and bacteria tolerance to Ni in soils. Moreover, it was observed that LC50 can be a reliable method for monitoring chemically resistant microorganisms directly in the environment to improve the use of microorganisms for the bioremediation of oil contaminated soils and in monitoring of antibiotic resistant microorganisms in natural ecosystems.

scholarly journals Oxygen Consumption in Ammocoetes of the Lamprey Ichthyomyzon Hubbsi Raney

1970 ◽  
Vol 53 (1) ◽  
pp. 47-57 ◽  
Author(s):  
B. J. HILL ◽  
I. C. POTTER
Keyword(s):  
Oxygen Consumption ◽  
Linear Regression ◽  
Continuous Flow ◽  
Medium Size ◽  
Aquatic Animals ◽  
Mean Values ◽  
Lower Vertebrates

1. A continuous flow respirometer suitable for measuring oxygen consumption in some small burrowing aquatic animals is described. 2. Rates of oxygen consumption in ammocoetes of the lamprey Ichthyomyzon hubbsi are low, with mean values at 15.5 °C ranging from 38.8 to 97.1 µl/g/h for large (3.44 g) and small (0.14 g) animals respectively. 3. A Q10 of 3.6 was found for medium-size animals (1.18 g) between 3.5 and 22.5 °C. 4. The slope of the logarithmic linear regression relating weight and oxygen consumption was 0.718 at 15.5°C. 5. The rates of oxygen consumption are discussed with respect to the ecology of ammocoetes and compared with those obtained for other lower vertebrates.

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