scholarly journals Biomarker Responses of Spanish Moss Tillandsia usneoides to Atmospheric Hg and Hormesis in This Species

2021 ◽  
Vol 12 ◽  
Author(s):  
Xingyue Sun ◽  
Peng Li ◽  
Guiling Zheng
Keyword(s):  
Superoxide Anion ◽  
Environmental Pollutant ◽  
Dose Effect ◽  
Coefficient Of Determination ◽  
Linear Relationships ◽  
Mda Content ◽  
Tillandsia Usneoides ◽  
Radical Content ◽  
Hg Pollution

Hg is an environmental pollutant with severe biotoxicity. Epiphytic Tillandsia species, especially Spanish moss T. usneoides, are widely used as the bioindicator of Hg pollution. However, the effects of different Hg concentrations on Tillandsia have been rarely studied and the occurrence of hormesis in Tillandsia species has not been determined. In this study, T. usneoides was subjected to stress induced by 15 concentrations of gaseous Hg ranging from 0 to 1.8 μg m–3 through a misting system and then Hg content and eight common biomarkers in leaves were measured. The results showed that leaf Hg content significantly increased with Hg concentration, showing a linear relationship. However, there were no obvious mortality symptoms, indicating that T. usneoides showed strong resistance to Hg. Conversely, there were no simple linear relationships between changes in various biomarkers following Hg treatment of T. usneoides and Hg concentration. With increasing Hg concentration, malondialdehyde (MDA) content did not change significantly, superoxide anion radical content decreased gradually, superoxide dismutase (SOD) content decreased to the bottom and then bounced back, electrical conductivity increased, and glutathione (GSH) and metallothionein (MT) content increased to the peak and then dropped. The coefficient of determination of the dose-effect curves between SOD, GSH, and MT contents and Hg concentration was high, and the dose-effect relationship varied with hormesis. The present study is first to confirm hormesis induced by heavy metal pollution in Tillandsia species.

scholarly journals Modeling Population Spatial-Temporal Distribution Using Taxis Origin and Destination Data

2021 ◽  
Vol 13 (7) ◽  
pp. 3727
Author(s):  
Fatema Rahimi ◽  
Abolghasem Sadeghi-Niaraki ◽  
Mostafa Ghodousi ◽  
Soo-Mi Choi
Keyword(s):  
Regression Analysis ◽  
Mean Squared Error ◽  
Population Distribution ◽  
Temporal Distribution ◽  
Coefficient Of Determination ◽  
Temporal Modeling ◽  
Location Data ◽  
Time Period ◽  
Proposed Model

During dangerous circumstances, knowledge about population distribution is essential for urban infrastructure architecture, policy-making, and urban planning with the best Spatial-temporal resolution. The spatial-temporal modeling of the population distribution of the case study was investigated in the present study. In this regard, the number of generated trips and absorbed trips using the taxis pick-up and drop-off location data was calculated first, and the census population was then allocated to each neighborhood. Finally, the Spatial-temporal distribution of the population was calculated using the developed model. In order to evaluate the model, a regression analysis between the census population and the predicted population for the time period between 21:00 to 23:00 was used. Based on the calculation of the number of generated and the absorbed trips, it showed a different spatial distribution for different hours in one day. The spatial pattern of the population distribution during the day was different from the population distribution during the night. The coefficient of determination of the regression analysis for the model (R2) was 0.9998, and the mean squared error was 10.78. The regression analysis showed that the model works well for the nighttime population at the neighborhood level, so the proposed model will be suitable for the day time population.

scholarly journals A Multimethod Analysis for Average Annual Precipitation Mapping in the Khorasan Razavi Province (Northeastern Iran)

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 592
Author(s):  
Mehdi Aalijahan ◽  
Azra Khosravichenar
Keyword(s):  
Regional Planning ◽  
Interpolation Method ◽  
Absolute Error ◽  
Rain Gauge ◽  
Annual Precipitation ◽  
Coefficient Of Determination ◽  
Distance Weighting ◽  
Average Annual Precipitation ◽  
Inverse Distance

The spatial distribution of precipitation is one of the most important climatic variables used in geographic and environmental studies. However, when there is a lack of full coverage of meteorological stations, precipitation estimations are necessary to interpolate precipitation for larger areas. The purpose of this research was to find the best interpolation method for precipitation mapping in the partly densely populated Khorasan Razavi province of northeastern Iran. To achieve this, we compared five methods by applying average precipitation data from 97 rain gauge stations in that province for a period of 20 years (1994–2014): Inverse Distance Weighting, Radial Basis Functions (Completely Regularized Spline, Spline with Tension, Multiquadric, Inverse Multiquadric, Thin Plate Spline), Kriging (Simple, Ordinary, Universal), Co-Kriging (Simple, Ordinary, Universal) with an auxiliary elevation parameter, and non-linear Regression. Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and the Coefficient of Determination (R2) were used to determine the best-performing method of precipitation interpolation. Our study shows that Ordinary Co-Kriging with an auxiliary elevation parameter was the best method for determining the distribution of annual precipitation for this region, showing the highest coefficient of determination of 0.46% between estimated and observed values. Therefore, the application of this method of precipitation mapping would form a mandatory base for regional planning and policy making in the arid to semi-arid Khorasan Razavi province during the future.

Determination of dose effect of thermal neutrons on the basis of external ?-radiation

Atomic Energy ◽  
1958 ◽  
Vol 4 (3) ◽  
pp. 401-402 ◽  
Author(s):  
A. G. Istomina ◽  
I. B. Keirim-Markus
Keyword(s):  
Dose Effect ◽  
Thermal Neutrons ◽  
External Radiation

scholarly journals A NON-DESTRUCTIVE METHOD FOR ESTIMATING LEAF AREA OF Ceiba glaziovii (Kuntze) K. Schum.

FLORESTA ◽  
2019 ◽  
Vol 50 (1) ◽  
pp. 1063
Author(s):  
João Everthon da Silva Ribeiro ◽  
Francisco Romário Andrade Figueiredo ◽  
Ester Dos Santos Coêlho ◽  
Walter Esfrain Pereira ◽  
Manoel Bandeira de Albuquerque
Keyword(s):  
Leaf Area ◽  
Regression Models ◽  
Information Criterion ◽  
Coefficient Of Determination ◽  
Linear Measurements ◽  
Maximum Width ◽  
Bias Index ◽  
Different Shapes ◽  
Non Destructive

The determination of leaf area is of fundamental importance in studies involving ecological and ecophysiological aspects of forest species. The objective of this research was to adjust an equation to determine the leaf area of Ceiba glaziovii as a function of linear measurements of leaves. Six hundred healthy leaf limbs were collected in different matrices, with different shapes and sizes, in the Mata do Pau-Ferro State Park, Areia, Paraíba state, Northeast Brazil. The maximum length (L), maximum width (W), product between length and width (L.W), and leaf area of the leaf limbs were calculated. The regression models used to construct equations were: linear, linear without intercept, quadratic, cubic, power and exponential. The criteria for choosing the best equation were based on the coefficient of determination (R²), Akaike information criterion (AIC), root mean square error (RMSE), Willmott concordance index (d) and BIAS index. All the proposed equations satisfactorily estimate the leaf area of C. glaziovii, due to their high determination coefficients (R² ≥ 0.851). The linear model without intercept, using the product between length and width (L.W), presented the best criteria to estimate the leaf area of the species, using the equation 0.4549*LW.

scholarly journals The Effect of Financial Leverage, Operating Leverage and Current Ratio on Profitability at PT. Manunggal Persada Jakarta

2019 ◽  
Vol 3 (2) ◽  
pp. 135
Author(s):  
Waluyo Jati
Keyword(s):  
Hypothesis Testing ◽  
Regression Coefficient ◽  
Sampling Technique ◽  
Coefficient Of Determination ◽  
Analysis Tool ◽  
Financial Leverage ◽  
Current Ratio ◽  
Independent Variable ◽  
Operating Leverage

Funds can be obtained from company owners or from outside parties. The purpose of this study was to determine the effect of financial leverage, operating leverage and current ratio on profitability at PT. Manunggal Persada Jakarta. The method used in this research is descriptive with an associative approach, the sampling technique used is proportional random sampling using the census or saturated sampling method with a sample of 7 years of financial statements. The analysis tool uses classical assumption testing, regression testing, determination coefficient testing and hypothesis testing. The results of the study concluded that the regression coefficient value of Financial leverage of 0.005 was positive with a contribution of 19.3%. Hypothesis testing obtained a significance value of 0.324> 0.05. Regression coefficient value of Operating leverage of 0.001 is positive with a contribution of 16.5%. Hypothesis testing obtained a significance value of 0.368> 0.05. Current coefficient regression value of 0.158 is positive with a contribution of 31.9%. Hypothesis testing obtained a significance value of 0.187> 0.05. Obtained a regression equation Y = 0.110 + 0.009X1 + 0.001X2 + 0.177X3, the regression coefficient value of each positive independent variable with a correlation of 0.927 and a coefficient of determination of 85.8% while the remaining 14.2% is influenced by other factors. Hypothesis testing obtained by calculating Fcount> Ftable or (6.064> 4.120). Thus simultaneously there is a positive and significant effect between financial leverage, operating leverage and current ratio to rentability.

scholarly journals The Influence Of International Brand Image Toward Guest's Decision To Stay At The Four Star Hotel In Lampung

2021 ◽  
Vol 4 (1) ◽  
pp. 38
Author(s):  
Dina Mayasari Soewoyo ◽  
Handono W Widodo
Keyword(s):  
Brand Image ◽  
Linear Regression Analysis ◽  
Software Tool ◽  
Primary Data ◽  
Coefficient Of Determination ◽  
Analysis Technique ◽  
Independent Variable ◽  
Decision To Stay ◽  
Decisions To Stay

<div class="WordSection1"><p>This survey research using the quantitative method was carried out during the Covid-19 pandemic, from May to August 2020 at the 4-star hotel in Lampung Province, Indonesia. The purpose of this study was to determine the influence of the independent variable, namely the image of the international hotel brand toward the dependent variable of guests' decisions to stay at the hotel. Primary data of the study were obtained from the results of distributing questionnaires which were carried out directly to 60 guests who were staying, as research samples and measured using a Likert scale of 1 - 4. Apart from distributing questionnaires, research data collection was also gained through observation, documentation, and literature review. All data collected were then grouped, reduced, tabulated and processed, analyzed descriptively, and statistically, in accordance with the context of the problem being studied using the SPSS 22.0 software tool.</p><p>Based on the simple linear regression analysis technique T-test (partial), R test and R square test, it was found that the value of T count (9,048) was greater than the T table (1,671), with a significance value of 0 or below the significance limit of 0.05. Both variables have a correlation coefficient of 0.765 and a coefficient of determination of 0.585. So it can be concluded that the international hotel brand image has a strong, positive, and significant influence on guest decisions to stay at the 4-star hotel in Lampung, with an effect of 58.5% while the rest, namely 41.5%, is influenced by other variables not examined in this study.</p></div><br clear="all" /><p><em> </em></p>

scholarly journals Kontribusi Penguasaan Semantik terhadap Kemampuan Membaca Pemahaman Mahasiswa IIPK Universitas Negeri Padang

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Afnita .
Keyword(s):  
Reading Comprehension ◽  
Significant Relationship ◽  
Information Science ◽  
Coefficient Of Determination ◽  
Library And Information Science ◽  
Reading Texts

This study aims to determine the contribution of semantic mastery to the ability of the Archives, Library and Information Science (IIPK) students in comprehending the reading texts. The result of this study indicates that the semantic mastery has a positive and significant relationship (with a coefficient of determination of 0.524). This means that the reading comprehension of IIPK students of UNP is 25.4% determined by mastery of semantics, and the remaining 74.6% is determined by other factors. Keywords: semantic mastery, reading comprehension, contribution

scholarly journals Photostability study of amlodipine besylate tablets packed in primary packaging

2021 ◽  
Vol 10 (1) ◽  
pp. 20-28
Author(s):  
Ivana Savić-Gajić ◽  
Ivan Savić ◽  
Predrag Sibinović ◽  
Valentina Marinković
Keyword(s):  
Mobile Phase ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Hplc Method ◽  
Coefficient Of Determination ◽  
Amlodipine Besylate ◽  
Limit Of Quantification ◽  
First Order Kinetics ◽  
The Given

In this study, the modified stability-indicating RP-HPLC method was validated for quantitative analysis of amlodipine besylate in the presence of its impurity D (3-ethyl 5-methyl 2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-6-methylpyridine-3,5-dicarboxylate). The method was applied for the determination of an analyte in the tablets and irradiated samples packed in the primary packaging (Alu/PVC/PVDC blister packaging). The efficient chromatographic separation was achieved using a ZORBAX Eclipse XDB-C18 column (4.6×250 mm, 5 mm) with isocratic elution of mobile phase which consisted of acetonitrile:methanol:triethylamine solution (15:35:50, v/v/v) (pH 3.0). The flow rate of the mobile phase was 1 mL min-1, while the detection of amlodipine besylate was carried out at 273 nm. Amlodipine besylate and its impurity D were identified at the retention times of 16.529 min and 2.575 min, respectively. The linearity of the method with the coefficient of determination of 0.999 was confirmed in the concentration range of 10 - 75 µg mL-1 for amlodipine besylate. The limit of detection was 0.2 µg mL-1, while the limit of quantification was 0.66 µg mL-1. After UV and Vis radiation of the tablets packed in the primary packaging, the content of amlodipine besylate was reduced by 22.38% and 19.89%, respectively. The presence of new degradation products was not detected under the given chromatographic conditions. The photodegradation of amlodipine besylate followed pseudo-first-order kinetics. Based on the half-life of amlodipine besylate (38.4 days for UV radiation and 43.3 days for Vis radiation), it was concluded that amlodipine besylate in the tablets has satisfactory photostability after its packing in the Alu/PVC/PVDC blister packaging.

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