Automatic topic DETECTION seems unavoidable in social media analysis due to big text data which their users generate. Clustering-based methods are one of the most important and up-to-date categories in topic DETECTION. The goal of this research is to have a wide study on this category. Therefore, this paper aims to study the main components of clustering-based-topic-DETECTION, which are embedding methods, distance metrics, and clustering algorithms. Transfer learning and consequently pretrained language models and word embeddings have been considered in recent years. Regarding the importance of embedding methods, the efficiency of five new embedding methods, from earlier to recent ones, are compared in this paper. To conduct our study, two commonly used distance metrics, in addition to five important clustering algorithms in the field of topic DETECTION, are implemented by the authors. As COVID-19 has turned into a hot trending topic on social networks in recent years, a dataset including one-month tweets collected with COVID-19-related hashtags is used for this study. More than 7500 experiments are performed to determine tunable parameters. Then all combinations of embedding methods, distance metrics and clustering algorithms (50 combinations) are evaluated using Silhouette metric. Results show that T5 strongly outperforms other embedding methods, cosine distance is weakly better than other distance metrics, and DBSCAN is superior to other clustering algorithms.

Purpose: Application of heavy forces to maxillary dentition during treatment with headgear, induces high concentration of STRESSes in periodontal tissue. Quantification of this STRESS is of great concern in orthodontics. This study was designed to investigate the quantity and quality of STRESS response in the PDL of maxillary first molar which was subjected to high pull headgear traction using Finite Element method.Methods and Material: In an experimental study, a three-dimensional finite element model of maxillary dentition, consisting of 17096 elements and 23013 nodes, was developed based on a young human skull. The forces were applied to the maxillary first molar in the stabilized Arch by means of a rectangular full size arch wire in (022) slot bracket. Mechanical properties of this model were based on previous studies. A 350 gram force was used for high pull headgear to affect the dentition (+30 degree) and STRESS distribution was investigated in buccal, palatal, mesial and distal side and in cervical, middle, apical sections of the PDL. The quantity of STRESSes were expressed as principal STRESSes (1,2,3), while the negative and positive signs indicated compressive and tensile STRESSes.Results: The buccal surface of PDL of mesiobuccal root and the buccal, palatal and distal surface in cervical region of PDL of distobuccal root and the distal surface of the PDL of palatal root had received a great deal of STRESSes, in addition, the over all STRESS distribution in roots of molar had intrusive nature.Conclusion: The extension of high STRESS concentration areas observed after using high pull headgear is limited to some root surfaces specially the distobuccal root.

Background: The most frequently used test for evaluation of fetal health is the Non STRESS Test (NST). Unfortunately it has a high incidence of false positive results. The combination of vibroacoustic stimulation with the NTS has been shown to reduce non reactive results.Methods: A tests assessment method was chosen with a simple randomized sampling. 40 pregnant women with non reactive NST in the first 20 minutes who received VAS in one of Tehran University's Hospitals were compared with BPP scores. A vibroacoustic stimulation was applied for a 3 seconds on the maternal abdomen and fallowed within 10 minutes. Data collection tools were NST, sonography instruments, NST result paper, tooth brusher, watch, demographic questioner and check list. Data analysis was made by descriptive static and by using the Fisher's Exact Test (with level of significant at p<0/05). All statistical analysis were performed using an spss/win.Results: After VAS, 70% of non reactive tracing became reactive. All cases with fetal reactivity response after a VAS had a subsequent BPP score of 8 (negative predictive value of 100%). False positivity of VAS was lower than NST.Conclusion: VAS offers benefits, by decreasing the incidence of non reactive test and reducing test time. VAS lowers the rate of false positive NST. VAS is safe and allows more efficient of prenatal services. This test could be used as a rapid antepartum test to predict fetal well-being.

The purpose of this study was comparing the STRESS of breast cancer patients to that of healthy women. A sample of 65 breast cancer patients were selected from "Imam-Khomeini Cancer Institute" (from summer to autumn of 2008). They were chosen from the available patients who were diagnosed with cancer for less than two months. Variables such as marital status, economic status, age and education were taken into consideration in both the experimental and the control groups. Pickle's "life event" questionnaire (1971) was used to assess the STRESS in those groups. The data were analyzed using t-test. The results suggest that the STRESS in breast cancer patients is significantly higher than others. Moreover, women who bereaved the loss of a relative, had unwanted pregnancy or experienced divorce had more STRESS.

Introduction: Pulsed photoacoustic imaging with wideband medical application is a technique in which the absorption of optieal pulse in chromophores produces ultrasonic thermoelastic waves. The waves are detected by an ultrasonic transducer at the surface of the tissue. The transducer with adequate resolution and acoustic sensitivity provides molecular imaging of superficial tissue structures such as the microvessels and skin. In this article, the sensitivity of the optical DETECTION systems were measured in comparison with that of the calibrated hydrophone under the same experimental conditions. Material and Methods: A continuous Nd: YAG laser, a pulsed Nd: YAG laser, an optical STRESS DETECTION system, a Fabry Perot DETECTION system, a needle hydrophone, a fast-photodiode and a 500 MHz digital oscilloscope were used. Laser pulses (energy = 10 mJ, pulsewidth = 6 ns) were delivered via an optical fiber (600 mm) into an aqueous solution of Indocyanine Green (ICG). The pulses absorbed in the solution, and then acoustic waves produced and received by ultrasonic transducer at the surface of the tissue. The other side of the transducer was illuminated by the continuous laser at the wavelength of 532 nm .The modulated optical beam was detected by the photodiode and the digital oscilloscope. Therefore, a photoacoustic signal was observed as a bipolar signal on the oscilloscope monitor.The sensitivity of the of the optical STRESS transducer was measured in comparison with a Fabry Perot DETECTION system and a needle hydrophone by measuring a signal to noise ratio (SNR) and a noise equivalent pressures (NEP).Results: The SNR of hydrophone, optical STRESS transducer and Fabry Perot were 56dB, 45 dB and 26 dB respectively. NEP of hydrophone, Fabry Perot DETECTION system and optical STRESS DETECTION system were 11 kPa, 13 kPa and 15 kPa, respectively. So NEP of Fabry Perot was 2 kPa higher than that of the Optical STRESS DETECTION system.Discussion: NEP of Fabry Perot is higher that of the optical STRESS DETECTION system. Because the bandwidth of the Fabry Perot was 8 MHz higher than that of the optical STRESSes DETECTION system. Conclusion: The combination of high sensitivity and the small active area makes the optical STRESS system particularly suitable for photoacoustic imaging applications.

Germination vigour is one of the most important factors for plant stablishing under drought STRESS. In order to detect of quantitative trait loci related to drought tolerance in germination stage a genetic map was provided by 74 SSR marker and 192 individuals of F2:4 derived from cross between Tarom mahalli´Khazar population. The hundred seeds of 20 families were used for recording of germination rate, radical length and plumule length. Seventy four SSR markers grouped in 12 linkage groups. Thirteen QTLs were detected for traits. Three QTLs were mapped on chromosome 1 that increased drought tolerance in germination stage in rice. Out of these QTLs, qGR-1a distinguished as major effect and explained 26.27% of the total variation. Correlations between traits and overlapping QTLs in RM466-RM259 interval provided a good region for gene pyramiding and marker assisted programs.

Damages or cracks change the natural frequencies and the mode shapes of the structures. Therefore, the modal parameters could be used in damage DETECTION or structural health monitoring techniques. Based on the knowledge of the authors, most researches in this field have been focused on one-dimensional problems, e. g. beams, trusses, columns, and frames. It seems that the main reason for the lack of comprehensive researches is the huge computational cost for two or three-dimensional problems involved with the finite-element modeling. In order to reduce the costs, two distinct techniques have been utilized here. Firstly, instead of using the genetic algorithm method, the particle swarm optimization (PSO) technique has been applied for finding the best solution. Secondly, instead of applying the fine meshes for calculation of the modal parameters in the finite-element modeling, the course meshes are used. In this paper, the combination of the frequencies and the mode shapes as an objective function has been applied in the optimization procedure for damage DETECTION of two-dimensional plane STRESS type problems. For this purpose, the finite-element computer program has been developed in MATLAB environment for the required calculations. The results show that non-gradient-based optimization techniques such as GA and PSO have been successfully detected the existence, location and the intensities of the pre-defined damage scenarios.