scholarly journals Ammonium Pretreatment and Addition Improve Stability of Environmental Parameters and Biogas Production under Anaerobic Co-digestion of Rice Straw and Dairy Manure

2018 ◽  
Author(s):  
Yun Tang ◽  
Shuzhen Zou ◽  
Di Kang
Keyword(s):  
Environmental Factors ◽  
Biogas Production ◽  
Environmental Parameters ◽  
Ammonium Hydroxide ◽  
Variable Coefficients ◽  
Dairy Manure ◽  
Response Relationship ◽  
Environment Factors ◽  
Pretreatment Conditions ◽  
The Stability

AbstractThis paper optimized the anaerobic digestion (AD) pretreatment process, identified the relationship between stability of environmental factors and biogas production under ammonium hydroxide (NH3·H2O) pretreatment and analyzed the reason of NH3·H2O pretreatment to increase biogas production. Variable coefficients (CVs) of environmental factors were calculated to study the stability of environmental factors during AD process. The effect of initial AD environment factors on the stability of environmental factors during AD process was analyzed by redundancy analysis. Path analysis was used to analyze the response relationship the stability of environmental factors between and total biogas production (TBP). Results showed that pretreatment at 8% for 4 days, the TBP produced the highest value (302.5mL/g TS) and significantly higher than the other values (P < 0.01). NH3·H2O pretreatment had effect on the initial AD environment factors and the environment factors during AD process. Under the NH3·H2O pretreatment conditions, the stability of environment factors during AD process was affected by initial AD environment factors, while they had direct and indirect influences on the TBP. This research concluded that NH3·H2O pretreatment improved TBP via changing the initial environment of AD and the stability of environment factors during AD process, as well as the response relationship among initial AD environment factors and the stability of environment factors during AD process and biogas production, the changes improved the stability of environmental factors and made the environment more suitable for AD.

scholarly journals Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

2021 ◽  
Vol 13 (2) ◽  
pp. 325
Author(s):  
Leon Biscornet ◽  
Christophe Révillion ◽  
Sylvaine Jégo ◽  
Erwan Lagadec ◽  
Yann Gomard ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Environmental Factors ◽  
Control Strategies ◽  
Sampling Site ◽  
Rattus Rattus ◽  
Environmental Parameters ◽  
Environmental Indicators ◽  
Small Island ◽  
Urban Landscapes ◽  
Infection Prevalence

Leptospirosis, an environmental infectious disease of bacterial origin, is the infectious disease with the highest associated mortality in Seychelles. In small island territories, the occurrence of the disease is spatially heterogeneous and a better understanding of the environmental factors that contribute to the presence of the bacteria would help implement targeted control. The present study aimed at identifying the main environmental parameters correlated with animal reservoirs distribution and Leptospira infection in order to delineate habitats with highest prevalence. We used a previously published dataset produced from a large collection of rodents trapped during the dry and wet seasons in most habitats of Mahé, the main island of Seychelles. A land use/land cover analysis was realized in order to describe the various environments using SPOT-5 images by remote sensing (object-based image analysis). At each sampling site, landscape indices were calculated and combined with other geographical parameters together with rainfall records to be used in a multivariate statistical analysis. Several environmental factors were found to be associated with the carriage of leptospires in Rattus rattus and Rattus norvegicus, namely low elevations, fragmented landscapes, the proximity of urbanized areas, an increased distance from forests and, above all, increased precipitation in the three months preceding trapping. The analysis indicated that Leptospira renal carriage could be predicted using the species identification and a description of landscape fragmentation and rainfall, with infection prevalence being positively correlated with these two environmental variables. This model may help decision makers in implementing policies affecting urban landscapes and/or in balancing conservation efforts when designing pest control strategies that should also aim at reducing human contact with Leptospira-laden rats while limiting their impact on the autochthonous fauna.

scholarly journals Risk and Environmental Factors Associated with the Presence of Canine Parvovirus Type 2 in Diarrheic Dogs from Thessaly, Central Greece

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 590
Author(s):  
Maria Kantere ◽  
Labrini V. Athanasiou ◽  
Alexios Giannakopoulos ◽  
Vassilis Skampardonis ◽  
Marina Sofia ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Clinical Symptoms ◽  
Gastrointestinal Disease ◽  
Environmental Parameters ◽  
Canine Parvovirus ◽  
Geographical Information ◽  
Factors Associated ◽  
Working Dogs ◽  
Canine Parvovirus Type 2

Canine parvovirus type 2 (CPV-2) primarily infects dogs, which are the main host reservoir, causing severe gastrointestinal disease associated with immunosuppression. The present study was conducted in Thessaly, Greece and aimed to identify risk and environmental factors associated with CPV-2 infection in diarrheic dogs. Fecal samples were collected from 116 dogs presenting diarrhea and were tested by polymerase chain reaction (PCR) for the presence of CPV-2 DNA. Supplementary data regarding clinical symptoms, individual features, management factors and medical history were also gathered for each animal during clinical evaluation. Sixty-eight diarrheic dogs were found to be positive for the virus DNA in their feces. Statistical analysis revealed that CPV-2 DNA was less likely to be detected in senior dogs, while working dogs, namely hounds and shepherds, had higher odds to be positive for the virus. Livestock density and land uses, specifically the categories of discontinuous urban fabric and of human population density, were identified as significant environmental parameters associated with CPV-2 infection by using Geographical Information System (GIS) together with the Ecological Niche Model (ENM). This is the first description of the environmental variables associated with the presence of CPV-2 DNA in dogs’ feces in Greece.

scholarly journals Novel finite point approach for solving time-fractional convection-dominated diffusion equations

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Xiaomin Liu ◽  
Muhammad Abbas ◽  
Honghong Yang ◽  
Xinqiang Qin ◽  
Tahir Nazir
Keyword(s):  
Variable Coefficients ◽  
Numerical Dispersion ◽  
Discrete Equation ◽  
Finite Point ◽  
Spatial Direction ◽  
Convection Diffusion ◽  
Convection Diffusion Equation ◽  
Tailored Finite Point Method ◽  
L1 Approximation ◽  
The Stability

AbstractIn this paper, a stabilized numerical method with high accuracy is proposed to solve time-fractional singularly perturbed convection-diffusion equation with variable coefficients. The tailored finite point method (TFPM) is adopted to discrete equation in the spatial direction, while the time direction is discreted by the G-L approximation and the L1 approximation. It can effectively eliminate non-physical oscillation or excessive numerical dispersion caused by convection dominant. The stability of the scheme is verified by theoretical analysis. Finally, one-dimensional and two-dimensional numerical examples are presented to verify the efficiency of the method.

scholarly journals Relationships between Environmental Factors and Pathogenic Vibrios in the Northern Gulf of Mexico

2010 ◽  
Vol 76 (21) ◽  
pp. 7076-7084 ◽  
Author(s):  
C. N. Johnson ◽  
A. R. Flowers ◽  
N. F. Noriea ◽  
A. M. Zimmerman ◽  
J. C. Bowers ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Water Column ◽  
Vibrio Vulnificus ◽  
Environmental Parameters ◽  
Sampling Period ◽  
Pathogenicity Factor ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin ◽  
Pathogenic Vibrios ◽  
Abundance And Distribution

ABSTRACT Although autochthonous vibrio densities are known to be influenced by water temperature and salinity, little is understood about other environmental factors associated with their abundance and distribution. Densities of culturable Vibrio vulnificus containing vvh (V. vulnificus hemolysin gene) and V. parahaemolyticus containing tlh (thermolabile hemolysin gene, ubiquitous in V. parahaemolyticus), tdh (thermostable direct hemolysin gene, V. parahaemolyticus pathogenicity factor), and trh (tdh-related hemolysin gene, V. parahaemolyticus pathogenicity factor) were measured in coastal waters of Mississippi and Alabama. Over a 19-month sampling period, vibrio densities in water, oysters, and sediment varied significantly with sea surface temperature (SST). On average, tdh-to-tlh ratios were significantly higher than trh-to-tlh ratios in water and oysters but not in sediment. Although tlh densities were lower than vvh densities in water and in oysters, the opposite was true in sediment. Regression analysis indicated that SST had a significant association with vvh and tlh densities in water and oysters, while salinity was significantly related to vibrio densities in the water column. Chlorophyll a levels in the water were correlated significantly with vvh in sediment and oysters and with pathogenic V. parahaemolyticus (tdh and trh) in the water column. Furthermore, turbidity was a significant predictor of V. parahaemolyticus density in all sample types (water, oyster, and sediment), and its role in predicting the risk of V. parahaemolyticus illness may be more important than previously realized. This study identified (i) culturable vibrios in winter sediment samples, (ii) niche-based differences in the abundance of vibrios, and (iii) predictive signatures resulting from correlations between environmental parameters and vibrio densities.

scholarly journals The impact of environmental variables on the spread of COVID-19 in the Republic of Korea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong Kwan Lim ◽  
Oh Joo Kweon ◽  
Hye Ryoun Kim ◽  
Tae-Hyoung Kim ◽  
Mi-Kyung Lee
Keyword(s):  
Environmental Factors ◽  
Virus Disease ◽  
Environmental Parameters ◽  
Environmental Data ◽  
Republic Of Korea ◽  
Metropolitan Region ◽  
Health Concern ◽  
Ozone Level ◽  
The Republic ◽  
The Impact

AbstractCorona virus disease 2019 (COVID-19) has been declared a global pandemic and is a major public health concern worldwide. In this study, we aimed to determine the role of environmental factors, such as climate and air pollutants, in the transmission of COVID-19 in the Republic of Korea. We collected epidemiological and environmental data from two regions of the Republic of Korea, namely Seoul metropolitan region (SMR) and Daegu-Gyeongbuk region (DGR) from February 2020 to July 2020. The data was then analyzed to identify correlations between each environmental factor with confirmed daily COVID-19 cases. Among the various environmental parameters, the duration of sunshine and ozone level were found to positively correlate with COVID-19 cases in both regions. However, the association of temperature variables with COVID-19 transmission revealed contradictory results when comparing the data from SMR and DGR. Moreover, statistical bias may have arisen due to an extensive epidemiological investigation and altered socio-behaviors that occurred in response to a COVID-19 outbreak. Nevertheless, our results suggest that various environmental factors may play a role in COVID-19 transmission.

Co-Digestion of Food Waste and Dairy Manure for Biogas Production

2007 ◽  
Vol 50 (5) ◽  
pp. 1815-1821 ◽  
Author(s):  
H. M. El-Mashad ◽  
R. Zhang
Keyword(s):  
Food Waste ◽  
Biogas Production ◽  
Dairy Manure

Floristic study and assessment of the environmental factors governing the distribution of riparian plants in the Zat sub-Basin: Tensift Watershed, Morocco

2020 ◽  
Vol 45 (2) ◽  
pp. 7900-7915
Author(s):  
Mostakim Lahcen ◽  
Fetnassi Nidal ◽  
Ghamizi Mohamed
Keyword(s):  
Environmental Factors ◽  
Pearson Correlation ◽  
Ecological Status ◽  
Environmental Parameters ◽  
Quality Parameters ◽  
Phosphorus Concentration ◽  
Factors Affecting ◽  
Riparian Plants ◽  
Emergent Plants ◽  
Significant Difference

Measuring the phytodiversity and determining environmental factors affecting the abundance and distribution of riparian plants of Zat sub-basin in Morocco were carried out in this study. A hypothesis was tested whether there is any statistically significant difference in environmental parameters and plants communities among the Zat River and its tributaries. For this purpose, water quality parameters such as temperature, pH, salinity, electrical conductivity, Dissolved Oxygen, nitrate and phosphorus concentration, and riparian plants diversity were estimated at 17 stations along the Zat River and its tributaries during the periods (2018 and 2019). The Canonical Correspondence Analysis (CCA) and Pearson correlation were preformed to assess the relationship between environmental parameters, and the distribution and abundance of riparian plants inventoried. The presence of 113 species was recorded, distributed between 43 families and 97 genera, 9 of which were floating-leaved, 24 submerged, and 80 emergent plants. The rare and threatened species inventoried were represented by 7 taxa, whereas 6 species are reported as endemic. Raunkiaer classification showed a dominance of therophytes (38.39%) over the other groups. According to CCA, the abiotic parameters (DO, elevation, salinity and nitrate concentration) were statistically significant parameters governing the distribution and abundance of the riparian plants inventoried. The results obtained reveal the state of the riparian vegetation in the Zat subBasin, therefore we can consider them as a reliable component for the assessment of the ecological status of the aquatic environment.

scholarly journals Geographically weighted regression modelling of the spatial association between malaria cases and environmental factors in Cameroon.

2020 ◽  
Author(s):  
Marlvin Anemey Tewara ◽  
Liu Yunxia ◽  
Weiqiang Ling ◽  
Binang Helen Barong ◽  
Prisca Ngetemalah Mbah-Fongkimeh ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Spatial Variability ◽  
Geographically Weighted Regression ◽  
Environmental Variables ◽  
Vegetation Index ◽  
Spatial Association ◽  
Ordinary Least Squares ◽  
Variable Coefficients ◽  
Weighted Regression ◽  
Gwr Model

Abstract Background: Studies have illustrated the association of malaria cases with environmental factors in Cameroon but limited in addressing how these factors vary in space for timely public health interventions. Thus, we want to find the spatial variability between malaria hotspot cases and environmental predictors using Geographically weighted regression (GWR) spatial modelling technique.Methods: The global Ordinary least squares (OLS) in the modelling spatial relationships tool in ArcGIS 10.3. was used to select candidate explanatory environmental variables for a properly specified GWR model. The local GWR model used the global OLS candidate variables to examine, predict and explore the spatial variability between environmental factors and malaria hotspot cases generated from Getis-Ord Gi* statistical analysis. Results: The OLS candidate environmental variable coefficients were statistically significant (adjusted R2 = 22.3% and p < 0.01) for a properly specified GWR model. The GWR model identified a strong spatial association between malaria cases and rainfall, vegetation index, population density, and drought episodes in most hotspot areas and a weak correlation with aridity and proximity to water with an overall model performance of 0.243 (adjusted R2= 24.3%).Conclusion: The generated GWR maps suggest that for policymakers to eliminate malaria in Cameroon, there should be the creation of malaria outreach programs and further investigations in areas where the environmental variables showed strong spatial associations with malaria hotspot cases.

Analysis of Group Pile Foundation Environmental Factors Based on Bayes Estimation

2013 ◽  
Vol 351-352 ◽  
pp. 1278-1283
Author(s):  
Tao Xue ◽  
Jun Fa Xu
Keyword(s):  
Environmental Factors ◽  
Pile Foundation ◽  
Growth Process ◽  
Bayes Estimation ◽  
Fusion Algorithm ◽  
Environment Factors ◽  
Sutong Bridge ◽  
Mechanical Performances ◽  
The Impact ◽  
Group Pile

The environmental factors have complex effects on the bearing properties of group pile foundation. Based on the "growth" process of the Sutong Bridge and the combination characteristics of environment factors, the relationships between the measured values of the group pile foundation and environmental factors were established. Then, the correlation decision determinations between the measured values and environmental factors were obtained by using the Bayes estimation fusion algorithm. Finally, the impacts of different environment factors on the bearing properties of group pile foundation had been got. The results showed that the impact of seasonal temperatures on the mechanical performances of the group pile foundation is very large.

Optimal Physical Pretreatment Conditions for the Release of Carbohydrate and Protein from Dairy Manure

2013 ◽  
Vol 291-294 ◽  
pp. 383-389
Author(s):  
Jian Ping Sun ◽  
Jun Zhu
Keyword(s):  
Particle Size ◽  
Experimental Design ◽  
Optimum Condition ◽  
Reaction Temperature ◽  
Organic Materials ◽  
Dairy Manure ◽  
Physical Factors ◽  
Test Results ◽  
Release Rates ◽  
Pretreatment Conditions

Various physical factors including particle size, pH, temperature and so on may influence the release of organic materials from dry dairy manure. The effect of these factors on release of protein and carbohydrate was investigated in this study using Box-Behnken Experimental Design with three factors (particle size, temperature and pH) at three levels. Test results suggested that particle size of 0.15-0.25 mm accounted for almost half of the dry manure particles and the optimum condition for release of protein and carbohydrate were pH 2, particle size 1.0-1.4 mm under reaction temperature of 90 oC, under which the protein and carbohydrate release rates could reach 1570.57 and 2813.29 mg l-1, respectively. The degree to which these factors affected organics release was in the order from high to low of temperature > particle size > pH.

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