Bounds for the relative n-th nilpotency degree in compact groups

The line of investigation of the present paper goes back to a classical work of W. H. Gustafson of the 1973, in which it is described the probability that two randomly chosen group elements commute. In the same work, he gave some bounds for this kind of probability, providing information on the group structure. We have recently obtained some generalizations of his results for finite groups. Here we improve them in the context of the compact groups.Comment: 9 pages; to appear in Asian-European Journal of Mathematics with several improvement

Investigating the Effects of Several Parameters on the Growth of Chlorella vulgaris Using Taguchi's Experimental Approach

Algae are part of photosynthetic organisms that play an important role in the aquatics nutrition. Like plants, algae need water, light and CO2 to grow. Using Taguchi's experimental approach (5 factors in four levels with 16 runs), effects of several parameters (NaCl, sodium bicarbonate and iron concentrations as well as light and temperature) on the growth of Chlorella vulgaris was studied. Increasing the concentrations of NaCl and sodium bicarbonate resulted in corresponding decreases in the growth of C. vulgaris. Media with 30.0g l-1NaCl did not indicate any algal growth. Also, with 9.0 g l-1sodium bicarbonate, biomass production was decreased. Chlorella vulgaris showed different growing behaviors at the various concentrations of iron (Fe+2) and at the different temperatures of this study. Maximum biomass production (approximately 3.56 g dry matter) was obtained at the 0.0 g l-1 sodium bicarbonate, 10.0g l-1NaCl, 18.0 µmol l-1 iron and at 30±2 °C. Yellow and blue lights increased the algal growth. Analysis of variance showed that salinity (i.e., the NaCl concentration) had the highest impact on the biomass production.

Gully erosion zonation mapping using integrated geographically weighted regression with certainty factor and random forest models in GIS

© 2018 Elsevier Ltd Every year, gully erosion causes substantial damage to agricultural land, residential areas and infrastructure, such as roads. Gully erosion assessment and mapping can facilitate decision making in environmental management and soil conservation. Thus, this research aims to propose a new model by combining the geographically weighted regression (GWR) technique with the certainty factor (CF) and random forest (RF) models to produce gully erosion zonation mapping. The proposed model was implemented in the Mahabia watershed of Iran, which is highly sensitive to gully erosion. Firstly, dependent and independent variables, including a gully erosion inventory map (GEIM) and gully-related causal factors (GRCFs), were prepared using several data sources. Secondly, the GEIM was randomly divided into two groups: training (70%) and validation (30%) datasets. Thirdly, tolerance and variance inflation factor indicators were used for multicollinearity analysis. The results of the analysis corroborated that no collinearity exists amongst GRCFs. A total of 12 topographic, hydrologic, geologic, climatologic, environmental and soil-related GRCFs and 150 gully locations were used for modelling. The watershed was divided into eight homogeneous units because the importance level of the parameters in different parts of the watershed is not the same. For this purpose, coefficients of elevation, distance to stream and distance to road parameters were used. These coefficients were obtained by extracting bi-square kernel and AIC via the GWR method. Subsequently, the RF-CF integrated model was applied in each unit. Finally, with the units combined, the final gully erosion susceptibility map was obtained. On the basis of the RF model, distance to stream, distance to road and land use/land cover exhibited a high influence on gully formation. Validation results using area under curve indicated that new GWR–CF–RF approach has a higher predictive accuracy 0.967 (96.7%) than the individual models of CF 0.763 (76.3%) and RF 0.776 (77.6%) and the CF-RF integrated model 0.897 (89.7%). Thus, the results of this research can be used by local managers and planners for environmental management

Generalized (2+1) dimensional black hole by Noether symmetry

We use the Noether symmetry approach to find $f(R)$ theory of $(2+1)$ dimensional gravity and $(2+1)$ dimensional black hole solution consistent with this $f(R)$ gravity and the associated symmetry. We obtain $f({R})=D_1 R({n}/{n+1})({R}/{K})^{1/n}+D_2 R+D_3$, where the constant term $D_3$ plays no dynamical role. Then, we find general spherically symmetric solution for this $f(R)$ gravity which is potentially capable of being as a black hole. Moreover, in the special case $D_1=0, D_2={1}$, namely $f(R)=R+D_3$, we obtain a generalized BTZ black hole which, other than common conserved charges $m$ and $J$, contains a new conserved charge Q. It is shown that this conserved charge corresponds to the freedom in the choice of the constant term $D_3$ and represents symmetry of the action under the transformation $R \rightarrow R'=R+D_3$ along the killing vector $\partial_{R}$. The ordinary BTZ black hole is obtained as the special case where $D_3$ is {\it fixed} to be proportional to the infinitesimal cosmological constant and consequently the symmetry is broken via Q=0. We study the thermodynamics of the generalized BTZ black hole and show that its entropy can be described by the Cardy-Verlinde formula.Comment: 13 pages, major revision, title chang

The effectiveness of pituitary extract from Crucian carp (Carassius auratus Linnaes, 1758) in inducing ovulation in veil tail gold fish (Carrassius auratus gibelio) and its effects on egg quality

The effectiveness of pituitary extract from Crucian carp (Carassius auratus Linnaes 1758) in inducing ovulation in Veil T ail Gold Fish (Carassius auratus gibelio Bloch 1783), was examined and the effect of maternal hormone treatment on egg quality in two types of fertilization (fertilization in aquarium and artificial fertilization), were evaluated in 22 degree C temperature. Fish were injected intrapritoneally with three doses of, 2, 3 and 4mg/kg B.W pituitary extract (PE). With increasing of pituitary dose, practical fecundity also increased from 1775 in control fish to 3201 in fish with 4mg /kg B.W of PE. Mean time to ovulation was reduced significantly (P<0.05) from 13 2h in control fish to 13h in fish with 4mg/kg B.W. Ovulated eggs from fish injected with 4mg/kg B.W of PE had lower fertility and hatching rates compared to egg s from fish injected with lower doses and the control fish. The methods of fertilization had no significant effect on the egg quality. In conclusion, the result s of this study showed that the pituitary extract of Crucian carp is effective in inducing and shortening of ovulation of Veil Tail Gold Fish and the suggested dose for this species is 3mg/kg B.W

Identification of erosion-prone areas using different multi-criteria decision-making techniques and gis

© 2018 The Author(s). The awareness of erosion risk in watersheds provides the possibility of identifying critical areas and prioritising protective and management plans. Soil erosion is one of the major natural hazards in the rainy mountainous regions of the Neka Roud Watershed in Mazandaran Province, Iran. This research assesses soil erosion susceptibility through morphometric parameters and the land use/land cover (LU/LC) factor based on multiple-criteria decision-making (MCDM) techniques, remote sensing and GIS. A set of 17 linear, relief and shape morphometric parameters and 5 LU/LC classes are used in the analysis. The aforementioned factors are selected as indicators of soil erosion in the study area. Then, four MCDM models, namely, the new additive ratio assessment (ARAS), complex proportional assessment (COPRAS), multi-objective optimisation by ratio analysis and compromise programming, are applied to the prioritisation of the Neka Roud sub-watersheds. The Spearman’s correlation coefficient test and Kendall’s tau correlation coefficient test indices are used to select the best models. The validation of the models indicates that the ARAS and COPRAS models based on morphometric parameters and LU/LC classes, respectively, achieve the best performance. The results of this research can be used by planners and decision makers in soil conservation and in reducing soil erosion

Assessment of landslide susceptibility using statistical- and artificial intelligence-based FR-RF integrated model and multiresolution DEMs

© 2019 by the authors. Landslide is one of the most important geomorphological hazards that cause significant ecological and economic losses and results in billions of dollars in financial losses and thousands of casualties per year. The occurrence of landslide in northern Iran (Alborz Mountain Belt) is often due to the geological and climatic conditions and tectonic and human activities. To reduce or control the damage caused by landslides, landslide susceptibility mapping (LSM) and landslide risk assessment are necessary. In this study, the efficiency and integration of frequency ratio (FR) and random forest (RF) in statistical- and artificial intelligence-based models and different digital elevation models (DEMs) with various spatial resolutions were assessed in the field of LSM. The experiment was performed in Sangtarashan watershed, Mazandran Province, Iran. The study area, which extends to 1072.28 km2, is severely affected by landslides, which cause severe economic and ecological losses. An inventory of 129 landslides that occurred in the study area was prepared using various resources, such as historical landslide records, the interpretation of aerial photos and Google Earth images, and extensive field surveys. The inventory was split into training and test sets, which include 70 and 30% of the landslide locations, respectively. Subsequently, 15 topographic, hydrologic, geologic, and environmental landslide conditioning factors were selected as predictor variables of landslide occurrence on the basis of literature review, field works and multicollinearity analysis. Phased array type L-band synthetic aperture radar (PALSAR), ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), and SRTM (Shuttle Radar Topography Mission) DEMs were used to extract topographic and hydrologic attributes. The RF model showed that land use/land cover (16.95), normalised difference vegetation index (16.44), distance to road (15.32) and elevation (13.6) were the most important controlling variables. Assessment of model performance by calculating the area under the receiving operating characteristic curve parameter showed that FR-RF integrated model (0.917) achieved higher predictive accuracy than the individual FR (0.865) and RF (0.840) models. Comparison of PALSAR, ASTER, and SRTM DEMs with 12.5, 30 and 90 m spatial resolution, respectively, with the FR-RF integrated model showed that the prediction accuracy of FR-RF-PALSAR (0.917) was higher than FR-RF-ASTER (0.865) and FR-RF-SRTM (0.863). The results of this study could be used by local planners and decision makers for planning development projects and landslide hazard mitigation measures

Spatial modelling of Gully erosion using GIS and R programing: A comparison among three data mining algorithms

© 2018 by the authors. Gully erosion triggers land degradation and restricts the use of land. This study assesses the spatial relationship between gully erosion (GE) and geo-environmental variables (GEVs) using Weights-of-Evidence (WoE) Bayes theory, and then applies three data mining methods-Random Forest (RF), boosted regression tree (BRT), and multivariate adaptive regression spline (MARS)-for gully erosion susceptibility mapping (GESM) in the Shahroud watershed, Iran. Gully locations were identified by extensive field surveys, and a total of 172 GE locationsweremapped. Twelve gully-related GEVs: Elevation, slope degree, slope aspect, plan curvature, convergence index, topographic wetness index (TWI), lithology, land use/land cover (LU/LC), distance from rivers, distance from roads, drainage density, and NDVI were selected to model GE. The results of variables importance by RF and BRT models indicated that distance from road, elevation, and lithology had the highest effect on GE occurrence. The area under the curve (AUC) and seed cell area index (SCAI) methods were used to validate the three GE maps. The results showed that AUC for the three models varies from 0.911 to 0.927, whereas the RF model had a prediction accuracy of 0.927 as per SCAI values, when compared to the other models. The findings will be of help for planning and developing the studied region

Risk analysis of the sea desalination plant at the 5th refinery of south pars gas company using Hazop procedures

Developments in designs complexity in the last two decades, has underlined the need for a comprehensive and systematic method capable of identifying and evaluating the process hazards. Amongst various methods presented to date, hazard and operability study (HAZOP) has received a considerable attention in the development of chemical and process industries. In this study, hazards in the desalination unit of a gas refinery in Asaluyeh, south of Iran was evaluated, using the PHA-PRO6 software, for which recommendations were made to avoid potential risks involved. Based on 8-years history of the refinery operation, maintenance records, accidents, safety vulnerabilities of the plant were evaluated. Employing the existing techniques and standards as well as installing appropriate flow control devices could ensure maintaining a normal operating pressure, which will in turn reduce pump stoppage and the unit being less out of service due to water flow shortage. Based on the HAZOP study results expressed here, the start-up procedure was also modified and problems associated with design, several mechanical parts and pipe lines installed were identified and adjusted.Keywords: HAZOP; hazard identity; sea water desalination unit; risk; gas refinery

Exogenous salicylic acid positively affects morpho-physiological and molecular responses of Impatiens walleriana plants grown under drought stress

The aim of this experiment was to investigate the exogenous application of salicylic acid (SA) on morpho-physiological and molecular characteristics of Impatiens walleriana plants grown under water deficit stress. Three levels of soil water contents (95, 85, and 75% of field capacity; FC) and three levels of SA (0, 1, and 2 mM) were applied on two impatient cultivars (‘Tempo’ and ‘Salmon’). The results showed that increasing water deficit stress negatively affected growth and flowering characteristics. On the contrary, the foliar application of SA reduced the adverse effect of water deficit stress and improved growth and ornamental plant attributes. Water deficit increased the amount of electrolyte leakage (EL), malondialdehyde (MDA), peroxidase (POD) and ascorbate peroxidase (APX) activities; and proline content. The expression of the gene encoding for Δ1-pyrroline-5-carboxylate synthetase (P5CS) was slightly increased under control treatment (95% FC + SA 0&nbsp;mM) and then significantly increased at 75% FC and after the SA treatments. The expression pattern of P5CR (Δ1-pyrroline-5-carboxylate reductase gene) was similar to that of P5CS, with differences in terms of intensity. The application of SA reduced the amount of EL and MDA through increased antioxidant activities and water balance. Overall, the results of this study showed that ‘Salmon’ cultivar was able to tolerate drought stress conditions better than ‘Tempo.’ The application of 2&nbsp;mM SA increased growth and physiological indices in drought-stressed impatient, mitigating the detrimental effects of water deficit in this important ornamental species