130 research outputs found
Evolution of Density Perturbations in a Cylindrical Molecular Cloud Using Smoothed Particle Hydrodynamics
Molecular clouds have a hierarchical structure from few tens of parsecs for giants to few tenth of a parsec for proto-stellar cores. Nowadays, our observational techniques are so advanced that it has become possible to detect the small-scale substructures inside the molecular cores. The question that arises is how these small condensations are formed. In the present research, we study the effect of ambipolar diffusion heating on the ubiquitous perturbations in a molecular cloud and investigate the possibility of converting them to dense substructures. For this purpose, a small azimuthal perturbation is implemented on the density of an axisymmetric two-dimensional cylindrical cloud, and its evolution is simulated bythe technique of two-fluid smoothed particle hydrodynamics. Theself-gravity is not included and the initial state has uniformdensity, temperature and magnetic field, parallel to theaxis of cylinder. In addition, all perturbed quantities are assumed todepend onlyon azimuth angle and time. Computer experiments show that if theambipolar diffusion heating is ignored, the perturbation willbe dispersed over the time. Including the heating due to ambipolardiffusion heats the matter in regions adjacent to the perturbation, thus,leading to the transfer of matter into the perturbed area. In this case, the density of perturbations can be increased. Also, the results ofsimulations show that an increase of the initial magnetic pressureleads to the intensification of difference between density ofperturbations and their surroundings (i.e. increasing of density contrast). This effect is due to the direct relationship of the drift velocity to the intensity of the magnetic field and its gradient. Simulations with different initial uniform densities show that the growth of relative density contrast is more clear with a special density. This result can be explained by the intensification of thermal instability in this special density
Analysis of Amiralmu’minin (As)’S Method in Correcting Beliefs and Behaviors
Imam Ali (AS) lived in a time that was saturated with the corruption derived from the caliphate of caliphs. The existence of this deep intellectual-behavioral gap in society led to abnormal behaviors and inappropriate attitudes. Imam Ali (AS) has used targeted and planned methods to correct false attitudes and abnormal behavior with the aim of creating security and peace in society. The best way of persuading people to correct misconceptions and correcting them is to clarify vague issues with arguments that have been among the practical tools of the Imams (AS), including Imam Ali (AS) in educating the people of the time. Accordingly, the purpose of this research is to examine and analyze the method of explanation in the Alavid system in order to modify the attitude and behavior based on its narratives in a descriptive-analytical method and to study its importance in the field of Islam. Findings indicate that the main method of Imam Ali (AS) in reforming attitude and behavior is the method of explanation, i.e. a rational explanation used in two non-cited and cited ways. Although Imam Ali (AS) did not speak without citation, but in some cases he did not express the citation. At the end of the research, the features of this method in the Alavid system have been investigated
Modified Carbon Nanotube Paste Electrode for Voltammetric Determination of Carbidopa, Folic Acid, and Tryptophan
A simple and convenient method is described for voltammetric determination of carbidopa (CD), based on its electrochemical oxidation at a modified multiwall carbon nanotube paste electrode. Under optimized conditions, the proposed method exhibited acceptable analytical performances in terms of linearity (over the concentration range from 0.1 to 700.0 μM), detection limit (65.0 nM), and reproducibility (RSD = 2.5%) for a solution containing CD. Also, square wave voltammetry (SWV) was used for simultaneous determination of CD, folic acid (FA), and tryptophan (TRP) at the modified electrode. To further validate its possible application, the method was used for the quantification of CD, FA, and TRP in urine samples
Weakly-Supervised Anomaly Detection in Surveillance Videos Based on Two-Stream I3D Convolution Network
The widespread adoption of city surveillance systems has led to an increase in the use of surveillance videos for maintaining public safety and security. This thesis tackles the problem of detecting anomalous events in surveillance videos. The goal is to automatically identify abnormal events by learning from both normal and abnormal videos. Most of previous works consider any deviation from learned normal patterns as an anomaly, which may not always be valid since the same activity could be normal or abnormal under different circumstances. To address this issue, the thesis utilizes the Two-Stream Inflated 3D (I3D) Convolutional Networks to extract spatial and temporal video features and demonstrates how it outperforms the 3D Convolutional Network (C3D) used in prior work as feature extractor. To avoid annotating abnormal activities in training videos, a weakly supervised anomaly detection model is implemented based on the Multiple Instance Learning (MIL) framework. The model considers normal and abnormal videos as bags and video clips as instances, learns a ranking model to predict high anomaly scores for video clips containing anomalies. The thesis further shows that the choice of features input, such as concatenating RGB and flow features, and careful choice of optimization settings, such as optimizer, can significantly improve the performance of the anomaly detection model on some evaluation metrics
Development of a highly sensitive voltammetric sensor for the detection of folic acid by using MoS2 and ionic liquid-modified carbon paste electrode
Background and purpose: Sensitive analytical determination of folic acid is important in clinical laboratories due to its versatile biological functions. Experimental approach: A simple folic acid sensor was successfully fabricated based on two-dimensional transition metal dichalcogenide MoS2 modified carbon ionic liquid paste electrode (MoS2-CILPE). The electrochemical properties of the fabricated electrode were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry. Key results: The fabricated sensor displayed excellent electroactivity towards folic acid using CV. Under optimal conditions (0.1 M PBS (pH 7.0)), the DPV oxidation peak current was proportional to folic acid concentration in the range from 5.0 μM to 100.0 μM with an estimated limit of detection of 1.0 µM and limit of quantification of 5.0 µM. Conclusion: The ability of the sensor for routine analyses was demonstrated by the detection of folic acid present in folic acid tablets and urine samples with appreciable recovery values.
Modeling leaf production and senescence in chickpea (Cicer arietinum L.): leaf lifetime
Quantitative information regarding leaf lifetime in chickpea (Cicer arietinum L.) is scarce. Data from a field
experiment with a range of planting date and density were analyzed to estimate leaf lifetime and its variation in
chickpea. The experiment was conducted under well-watered conditions. An average leaf lifetime of 23.5
physiological days was estimated. A physiological day is a calendar day with no limitation of photoperiod and
temperature for plant development. Planting date and density did not affect leaf lifetime. The results of this study
can be used in simulation models of chickpea
In vitro and in vivo antifungal properties of silver nanoparticles against Rhizoctonia solani, a common agent of rice sheath blight disease
Sheath blight disease in rice has caused major crop losses worldwide. Managing the causal agent of disease Rhizoctonia solani Kühn is difficult because of its broad host range and formation of sclerotia which can survive in harsh environmental conditions; therefore developing innovative disease management methods without application of hazardous chemicals has been considered as the main concern to maintain sustainable agriculture. This presented research has revealed the negative impact of Silver nanoparticles (SNPs) on R. solani and disease progress both in vitro and in vivo. The adverse effects of the SNPs on R. solani are significantly dependent on the quantity of SNPs, sprayed at different concentrations in vitro. The highest inhibition level against sclerotia formation and mycelia growth are 92 and 85%, respectively, at a SNPs concentration of 50 ppm. In vivo glasshouse experiments also showed that SNPs at the same concentration favorably affects both the fresh and dry weight of rice plants with a remarkable suppressive effect on the lesion development in leaves
Effects of organophosphate, diazinon on some haematological and biochemical changes in Rutilus frisii kutum (Kamensky, 1901) male brood stocks
The acute toxicity and effects of diazinon on some haematological parameters of kutum (Rutilus frisii kutum, Kamensky, 1901) weighing 613.33 ± 157.06 g were studied under static water quality conditions at 15 °C ± 2 ºC. These experiments were carried out based on the standard TRC, 1984 method over 4 days, and controlled for the effective water physicochemical factors having pH ranges of 7-8.2, total hardness 300 mgl^-1 (CaCO3), dissolved oxygen 7 mgl^-1. The results showed that the 96h LC50 value of diazinon was 0.4 mgl^-1 and that the maximum allowable concentration (MAC) value of this toxin was 0.04 mgl^-1. The second stage of experiments consisted of four treatments: LC0: 0 as blank, treatment A with a concentration of LC1: 0.107 mgl^-1, treatment B with a concentration of LC5: 0.157 mgl^-1, treatment C with a concentration of MAC value: 0.04 mgl^-1. Male brood stocks of R. frisii were treated with these concentrations for 45 days. The results showed that long-term exposure to diazinon causes a decrease in the erythrocyte count (RBC), haemoglobin (Hb), haematocrit (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), leucocyte count (WBC), lymphocyte, testosterone, iron (Fe), sodium (Na), lactate dehydrogenase (LDH) and cholinesterase (CHeS) (P0.05). The results showed that long-term exposure to low concentrations of diazinon causes changes in some haematological and biochemical parameters of R. frisii male brood stocks
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