FRMDN: Flow-based Recurrent Mixture Density Network

Recurrent Mixture Density Networks (RMDNs) are consisted of two main parts: a Recurrent Neural Network (RNN) and a Gaussian Mixture Model (GMM), in which a kind of RNN (almost LSTM) is used to find the parameters of a GMM in every time step. While available RMDNs have been faced with different difficulties. The most important of them is high$-$dimensional problems. Since estimating the covariance matrix for the high$-$dimensional problems is more difficult, due to existing correlation between dimensions and satisfying the positive definition condition. Consequently, the available methods have usually used RMDN with a diagonal covariance matrix for high$-$dimensional problems by supposing independence among dimensions. Hence, in this paper with inspiring a common approach in the literature of GMM, we consider a tied configuration for each precision matrix (inverse of the covariance matrix) in RMDN as (\(\Sigma _k^{ - 1} = U{D_k}U\)) to enrich GMM rather than considering a diagonal form for it. But due to simplicity, we assume \(U\) be an Identity matrix and \(D_k\) is a specific diagonal matrix for \(k^{th}\) component. Until now, we only have a diagonal matrix and it does not differ with available diagonal RMDNs. Besides, Flow$-$based neural networks are a new group of generative models that are able to transform a distribution to a simpler distribution and vice versa, through a sequence of invertible functions. Therefore, we applied a diagonal GMM on transformed observations. At every time step, the next observation, \({y_{t + 1}}\), has been passed through a flow$-$based neural network to obtain a much simpler distribution. Experimental results for a reinforcement learning problem verify the superiority of the proposed method to the base$-$line method in terms of Negative Log$-$Likelihood (NLL) for RMDN and the cumulative reward for a controller with fewer population size

Pesticides Removal Using Sorption to Iron Oxide Coated Sand

Environmental Engineerin

Development of Biological Permeable Barriers for Removal of 2,4,6 Trichlorophenol in Contaminated Groundwater

Civil Engineerin

Diagnostic Value of Cone-Beam Computed Tomography and Digital Periapical Radiography in Detection of Separated Instruments

Introduction: File Fracture is one of the most common problems during root canal treatment which can affect treatment procedure and prognosis, so it is important to diagnose and prevent it. The aim of this study was to evaluate and compare the diagnostic value of cone-beam computed tomography (CBCT) and digital periapical radiography for detection of separated instrument retained inside the canal. Methods and Materials: Ninety single-rooted extracted human teeth were selected and randomly divided into 3 groups (n=30). Group 1, separated file #10 at the 2-mm apical third of the root canal; group 2, separated file #35 at the 2-mm apical third of the root canal; and group 3, without a broken file (control group). The teeth were instrumented to size #30 and were shaped to size #55 and then the canals were obturated up to separated instrument, or the working length for the teeth without a separated instrument, with lateral condensation technique. After that all teeth were placed in dry skull, digital radiography and CBCT was taken. After data collection, data was analyzed using SPSS software by means of sensitivity, specificity, positive and negative predictive values, and frequency tables. Results: Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of digital periapical radiography in detection of a fractured file #10 in the canal was 96.7% and 63.3%, 76.7%, 73.1%, 67.6%, 70%, for CBCT, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of digital periapical radiography in detection of a fracture file #35 in the canal was 93.3%, 96.7%, 96.6%, 93.5% and 95%, and 36.7%, 76.7%, 61.1%, 54.8%, 56.66%, for CBCT, respectively. Conclusion: Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of digital periapical radiography was better than the CBCT technique in both sizes of broken files.Keywords: Broken File; Cone-Beam Computed Tomography; Digital Radiography; Separated Instrumen

Diagnostic Value of Cone-Beam Computed Tomography and Periapical Radiography In Detection of Vertical Root Fracture

Introduction: Vertical root fracture (VRF) is the longitudinal fracture of the root in endodontically treated teeth. Considering the limitations of two-dimensional radiographic images in detection of VRF and introduction of cone-beam computed tomography (CBCT), this study was designed to find the sensitivity, specificity and accuracy of CBCT and periapical (PA) radiography in detection of VRFs. Methods and Materials: This was a cross-sectional in vitro study on 80 extracted human single canal teeth including 40 maxillary and 40 mandibular teeth. After standardized endodontic treatment of the roots, VRF was induced in half of the teeth in each group, and other half were left without fracture. Teeth were inserted in dry maxillary and mandibular alveoli. PA radiographs and CBCT images were taken from the specimens. Data were analyzed with SPSS software. The McNemar test was used to evaluate the sensitivity, specificity and accuracy of images, and kappa coefficient was used to assess the degree of agreement between the observers. The level of significance was set at 0.05. Results: Sensitivity and specificity values of CBCT were 97.5% and 95%, respectively. However, for PA radiography the sensitivity and specificity were 67.5% and 92.5%, in order of appearance. Accuracy of CBCT (96.25%) and PA radiography (80%) in both jaws were significantly different (P=0.022). Two methods were not significantly different when testing specificity (P=0.298). Conclusion: This study showed that the sensitivity and accuracy of CBCT in detection of vertical root fracture are higher than periapical radiography. CBCT can be recommended to be used in detection of vertical root fractures

A multivariate comparison of electroencephalogram and functional magnetic resonance imaging to electrocorticogram using visual object representations in humans

Today, most neurocognitive studies in humans employ the non-invasive neuroimaging techniques functional magnetic resonance imaging (fMRI) and electroencephalogram (EEG). However, how the data provided by fMRI and EEG relate exactly to the underlying neural activity remains incompletely understood. Here, we aimed to understand the relation between EEG and fMRI data at the level of neural population codes using multivariate pattern analysis. In particular, we assessed whether this relation is affected when we change stimuli or introduce identity-preserving variations to them. For this, we recorded EEG and fMRI data separately from 21 healthy participants while participants viewed everyday objects in different viewing conditions, and then related the data to electrocorticogram (ECoG) data recorded for the same stimulus set from epileptic patients. The comparison of EEG and ECoG data showed that object category signals emerge swiftly in the visual system and can be detected by both EEG and ECoG at similar temporal delays after stimulus onset. The correlation between EEG and ECoG was reduced when object representations tolerant to changes in scale and orientation were considered. The comparison of fMRI and ECoG overall revealed a tighter relationship in occipital than in temporal regions, related to differences in fMRI signal-to-noise ratio. Together, our results reveal a complex relationship between fMRI, EEG, and ECoG signals at the level of population codes that critically depends on the time point after stimulus onset, the region investigated, and the visual contents used

Evaluating the Accuracy of Two Microleakage Assessment Methods for Mineral Trioxide Aggregate and Calcium-enriched Mixture Cement

Introduction: Multiple methods for evaluating microleakage have been introduced over the years, but there has been no agreement as to which technique will give more accurate results. The aim of this study was to compare the accuracy and results of fluid filtration and marginal adaptation methods for mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement apical plugs. Methods and Materials: A total of 250 single-rooted human teeth were collected. The teeth were decoronated, the root canals were prepared and open apex condition was stimulated by passing #1 to 4 Peeso Reamer drills from apical foramen. Five teeth were selected as the positive and negative controls and the rest of the samples were randomly allocated to two groups of MTA and CEM cement plugs. In each group, apical plug was placed into the canal. After the apical plugs were completely set, microleakage and marginal adaptation of the samples were evaluated using fluid filtration method and scanning electron microscopy (SEM), respectively. The obtained results were analyzed by independent-samples t test. Results: Gap between plug and dentin walls and air bubbles displacement was higher in MTA group compared to the CEM cement group, though this difference between MTA group and CEM cement group was not statistically significant. Conclusion: According to the obtained results, it seems that there is a direct relationship between the two methods of microleakage assessment. Keywords: Calcium-enriched Mixture Cement; Marginal Adaptation; Microleakage; Mineral Trioxide Aggregat

Glutathione Peroxidase Activity Assay with Colorimetric Method and Microplate Reading Format and Comparison with Chemiluminescence Method

Glutathione peroxidase (GPX) has a key role in the protection of organisms from oxidative damage. Many diseases and disorders are associated with changes in GPX activity. Therefore, its activity assay can be crucial in prevention, diagnosis and treatment of them. Several companies produce GPX activity assay kit but it is being imported to Iran which is expensive and time-consuming. This research has been done to investigate a simple, rapid and inexpensive method for GPX activity assay. In this study, GPX reduced cumene hydroperoxide while oxidized glutathione (GSH) to GSSG. The generated GSSG was reduced to GSH with consumption of NADPH by glutathione reductase. The decrease of NADPH absorption which was proportional to GPX activity measured at 340 nm with microplate reading format. Sensitivity, precision and accuracy have been examined. The results obtained by the colorimetric method compared with chemiluminescence method and correlation coefficient has been determined. Sensitivity of this method was 15 mU/ml. The coefficient of variation percent for intra and inter assay was less than 9.7 %. According to parallelism and recovery tests, ratio % and recovery %  ranged from 91% to 112% and correlation coefficient between the two methods was 0.9898 (n=60). Data from this study showed that the method has an acceptable sensitivity, precision and accuracy and can be suitable for both clinical and research studies. Indeed, this study is the first step of domestic commercial kit production purpose

Yield Stability in Chickpea (Cicer arietinum L.) and Study Relationship among the univariate and multivariate stability Parameters

Chickpea (Cicer arietinum L.) is traditionally grown as a rain fed crop globally,specifically in Middle East. Its seed is a rich source of protein for human consumption indeveloping countries such as Iran. The development of genotypes, which can be adaptedto a wide range of diversified environment, is the ultimate goal of plant breeders in a cropimprovement program. In this study, several univariate and multivariate stabilitymethods were used to evaluate the genotype × environment (GE) interaction in 17chickpea genotypes. Field experiments were carried out in 16 environments of Iran’schickpea producing areas to characterize GE interaction on grain yield of 17 chickpeagenotypes. Combined analysis of variance across environments indicated that bothenvironments and GE interactions influenced significantly the genotypes performancefor yield. Twenty univariate and multivariate stability methods and techniques were usedto describe the GE interaction and to define stable genotypes in relation to the yieldconsidered in this study. The different stability statistics which measured the differentaspects of stability was substantiated by Spearman’s rank correlation coefficient.According to Spearman’s rank correlation coefficient three groups of stability parameterscan be defined that the results of these different stability methods were variable. We usedgroup 1, include Lin and Binns superiority measure ( i P ), Hernandez et al (1993) parameter( i D ), GGE Biplot method and Principal coordinate method for introduction somegenotypes to farmers. The identified superior genotypes significantly differ from thelocal check cultivars and therefore farmers in semi arid areas of Iran can use thesegenotypes