Sharif Digital Repository

The gas chromatography retention indices of 168 pesticides were used to construct a robust quantitative structure - retention relationship (QSRR) model. After outlier detection by Cook's influence measurement, the remaining compounds were subjected to two different modeling strategies. The first one was stepwise multiple linear regression (stepwise-MLR). Results of this method revealed that 81.7 percent of variances of the response could be explained by the model. The other strategy was kernel orthogonal projection to latent structure (KOPLS). R2 and RMSE values for the prediction set established by Monte Carlo cross validation of the KOPLS were 0.906 and 0.093, respectively. Y-randomization... 

Transportation has significant and long lasting economical, social and environmental impacts, and so is an important dimension of urban sustainability. Some attempts have been made to develop sustainable transport indicators, STI. A few studies actually apply STI to compare sustainability among various world cities. In this paper various world cities ranked in terms of urban sustainable transport composite index. The study database is created from UITP databank: "Millennium cities database for sustainable mobility" or MCDST. Firstly sustainable transportation indicators were selected by reviewing past researches. Some indicators are edited or redefined. Consequently 9 STI were developed, 3... 

The impact of adding correlation to a population of neurons on the information and the activity of the population is one of the fundamental questions in recent system neuroscience. In this paper, we would like to introduce topology-based correlation at the level of storing patterns in a recurrent network. We then study the effects of topological patterns on the activity and memory capacity of the network. The general aim of the present work is to show how the repertoire of possible stored patterns is determined by the underlying network topology.Two topological probability rules for pattern selection in recurrent network are introduced. The first one selects patterns according to a... 

We prepared single-phase polycrystalline Gd1-xPrx Ba2Cu3O7-δ samples with x = 0, 0.10, 0.15, and 0.20. The deoxygenation process of these samples was performed by an annealing method. Electrical resistivity measurements revealed depression of the transition temperature with the increase of x and δ. We calculated the hole concentration in the CuO2 plane for different values of x and δ. A linear dependence of transition temperature and hole concentration in the CuO2 plane was found as a function of 2δ + x. It is proposed that a combination of the localization and filling of holes should be considered as the effective mechanisms for the appearance of the Pr anomaly in HTSCs  

STUDY DESIGN. Cross-cultural translation and psychometric testing were performed. OBJECTIVES. To cross-culturally translate the Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RDQ), and Quebec Back Pain Disability Scale (QDS) into Persian, and then investigate the psychometric properties of the Persian versions produced. SUMMARY OF BACKGROUND DATA. To the authors' knowledge, there is no validated instrument to measure functional status in Persian-speaking patients with low back pain (LBP) in Iran. To our knowledge, the widely used back-specific measures, the ODI, RDQ, and QDS, have not been translated and validated for Persian-speaking patients with LBP. METHODS. The... 

In this study isolated perfused rat muscle was used to examine the direct effect of temperature changes on the eccentric contraction-induced force and desmin loss. The left medial gastrocnemius muscle was separated and the entire lower limb was transferred into a prewarmed (35°C) organ bath. Temperature was adjusted to 31 or 39°C before and during eccentric contractions. Maximal isometric force and desmin loss were measured after 15 isometric or eccentric contractions. According to our data, organ bath temperature changes before or during eccentric contractions had no significant effect on force loss. However, a strong correlation between desmin loss and temperature changes before (r = 0.93,... 

In recent years, researchers have paid particular attention to safety, air pollution, and energy consumption, which are all affected by vehicle type. The primary objective of this study is to achieve a thorough understanding of the relationships of transportation attitudes, safety attitudes, personality, and lifestyle with vehicle type for the first time in Iran, as a developing country. For this purpose, an interview questionnaire was designed, and 740 participants were interviewed in Tehran. Vehicle types are categorized into seven groups: mini, compact, medium, heavy, Sport Utility Vehicle (SUV), pickup, and motorcycle. In the first stage, factor analysis was employed to identify the... 

The aim of this study is to assess the functional connectivity from resting state functional magnetic resonance imaging (fMRI) data. Spectral clustering algorithm was applied to the realistic and real fMRI data acquired from a resting healthy subject to find functionally connected brain regions. In order to make computation of the spectral decompositions of the entire brain volume feasible, the similarity matrix has been sparsified with the t-nearestneighbor approach. Realistic data were created to investigate the performance of the proposed algorithm and comparing it to the recently proposed spectral clustering algorithm with the Nystrom approximation and also with some well-known... 

A novel solid-phase microextraction (SPME) method was developed for isolation of dextromethorphan (DM) and its main metabolite dextrorphan (DP) from human plasma followed by GC-MS determination. Three different polymers, poly(dimethylsiloxane) (PDMS), poly(ethylenepropyleneglycol) monobutyl ether (Ucon) and polyethylene glycol (PEG) were synthesized as coated fibers using sol-gel methodologies. DP was converted to its acetyl-derivative prior to extraction and subsequent determination. The porosity of coated fibers was examined by SEM technique. Effects of different parameters such as fiber coating type, extraction mode, agitation method, sample volume, extraction time, and desorption... 

In this article, the relation between meteorological parameters and dust activities in western Iran has been studied. Satellite-based data achieved from TOMS are used to investigate the dust activities within a time period of 30 years. In the first part of this study, we examine the statistical trend of Aerosol Index (AI) and local meteorological parameters in 15 different stations. The same patterns of AI variations in all stations indicate that this region has always been subjected to dust storms which originate from similar sources in the neighboring countries that could be known as a sole dust transfer system. In the second part, we investigate the spatial correlation between the... 

Abnormalities in the topology of brain networks may be an important feature and etiological factor for psychogenic non-epileptic seizures (PNES). To explore this possibility, we applied a graph theoretical approach to functional networks based on resting state EEGs from 13 PNES patients and 13 age- and gender-matched controls. The networks were extracted from Laplacian-transformed time-series by a cross-correlation method. PNES patients showed close to normal local and global connectivity and small-world structure, estimated with clustering coefficient, modularity, global efficiency, and small-worldness metrics, respectively. Yet the number of PNES attacks per month correlated with a... 

Growth arrest-specific gene 6 (GAS6) is a growth factor-like cytokine whose function is related with vitamin K. This protein interacts with receptor tyrosine kinase proteins such as Tyro3, Axl, and TAM Receptor family, therefore affecting the tumorigenic processes via different mechanisms. GAS6-antisense 1 (GAS6-AS1) is a long non-coding RNAs (lncRNAs) that is transcribed from a genomic regions nearby GAS6. This lncRNA is also implicated in the pathobiology of cancer. We intended to judge the role of GAS6 and GAS6-AS1 in the pathogenesis of breast cancer through appraisal of their expression levels in breast cancer tissues and their paired neighboring non-cancerous samples. Expression of... 

Motivated by the fact that in computer vision data samples are matrices, in this paper, we propose a matrix-variate probabilistic model for canonical correlation analysis (CCA). Unlike probabilistic CCA which converts the image samples into the vectors, our method uses the original image matrices for data representation. We show that the maximum likelihood parameter estimation of the model leads to the two-dimensional canonical correlation directions. This model helps for better understanding of two-dimensional Canonical Correlation Analysis (2DCCA), and for further extending the method into more complex probabilistic model. In addition, we show that two-dimensional Linear Discriminant... 

The disguise of traditional monopolistic electricity markets into deregulated competitive ones has made 'price forecasting' a crucial strategy for both producers and consumers: for the producers, to maximize their profit and hedge against price volatilities and for the consumers to manage their utility. Electricity price forecasting has thus emerged as a progressive field of study and numerous researches have been conducted to improve and optimize the price forecast methods. This paper proposes a precise and computationally efficient method to perform price forecasting in deregulated power markets. A locally linear neuro-fuzzy model is developed for price forecasting. The model is trained by... 

We use the detrended fluctuation analysis (DFA), the detrended cross correlation analysis (DCCA) and the magnitude and sign decomposition analysis to study the fluctuations in the turbulent time series and to probe long-term nonlinear levels of complexity in weakly and high turbulent flow. The DFA analysis indicate that there is a time scaling region in the fluctuation function, segregating regimes with different scaling exponents. We discuss that this time scaling region is related to inertial range in turbulent flows. The DCCA exponent implies the presence of power-law cross correlations. In addition, we conclude its multifractality for high Reynold's number in inertial range. Further, we... 

A number of challenges including instability, nonconvergence, nonuniqueness, nonoptimality, and lack of a general guideline for inverse modelling have limited the application of automatic calibration by generic inversion codes in solving the saltwater intrusion problem in real-world cases. A systematic parameter selection procedure for the selection of a small number of independent parameters is applied to a real case of saltwater intrusion in a small island aquifer system in the semiarid region of the Persian Gulf. The methodology aims at reducing parameter nonuniqueness and uncertainty and the time spent on inverse modelling computations. Subsequent to the automatic calibration of the... 

Lake Urmia (LU) is the second largest hypersaline lake in the world. Lake Urmia's water level has dropped drastically from 1277.85 m to 1270.08 m a.s.l (equal to 7.77 m) during the last 20 years, equivalent to a loss of 70% of the lake area. The likelihood of lake-groundwater connection on the basin-scale is uncertain and understudied because of lack of basic data and precise information required for physically-based modeling. In this study, cross-correlation analysis is applied on a various time-frames of water level of the lake and groundwater levels (2001–2018) recorded in 797 observation wells across 17 adjacent aquifers. This provides insightful information on the lake-groundwater...