2,300 research outputs found

    A molecular-dynamics approach for studying the non-equilibrium behavior of x-ray-heated solid-density matter

    Full text link
    When matter is exposed to a high-intensity x-ray free-electron-laser pulse, the x rays excite inner-shell electrons leading to the ionization of the electrons through various atomic processes and creating high-energy-density plasma, i.e., warm or hot dense matter. The resulting system consists of atoms in various electronic configurations, thermalizing on sub-picosecond to picosecond timescales after photoexcitation. We present a simulation study of x-ray-heated solid-density matter. For this we use XMDYN, a Monte-Carlo molecular-dynamics-based code with periodic boundary conditions, which allows one to investigate non-equilibrium dynamics. XMDYN is capable of treating systems containing light and heavy atomic species with full electronic configuration space and 3D spatial inhomogeneity. For the validation of our approach we compare for a model system the electron temperatures and the ion charge-state distribution from XMDYN to results for the thermalized system based on the average-atom model implemented in XATOM, an ab-initio x-ray atomic physics toolkit extended to include a plasma environment. Further, we also compare the average charge evolution of diamond with the predictions of a Boltzmann continuum approach. We demonstrate that XMDYN results are in good quantitative agreement with the above mentioned approaches, suggesting that the current implementation of XMDYN is a viable approach to simulate the dynamics of x-ray-driven non-equilibrium dynamics in solids. In order to illustrate the potential of XMDYN for treating complex systems we present calculations on the triiodo benzene derivative 5-amino-2,4,6-triiodoisophthalic acid (I3C), a compound of relevance of biomolecular imaging, consisting of heavy and light atomic species

    Satellite Derived Sea surface temperature fronts in relation with Tuna catch In EEZ of Pakistan

    Get PDF
    Sea surface temperature (SST) is an important parameter in marine ecosystem studies as its relations of Fishery and other marine resources. In this study SST fronts have also been studied with relate to tuna fish catch data of April and August 2014 was acquired. Satellite derived MODIS daily products have been used to derive thermal fronts in the exclusive economic zone (EEZ) of Pakistan. Research results indicated that the Sea surface temperature gradually changed from 22C to 24C where Tuna catch is high and By Catch is low in frontal region. The further Relationship between these two data are discussed in this study and also made recommendations for in what way these two datasets should be handled. Remote sensing data and GIS tools are efficient and less time consuming for mapping and classifying sea surface temperature in a broader way. Survey of fishing resources is really time consumed and costly, Satellite Remote sensing data shows a promising tool to monitor fishery resources in a cost effective manner. Satellite data play an important role to identify fish aggregation zones and these techniques could also be used to forecast potential fishing zones by measuring oceanic parameters which influence on fish distribution on a broader scale and these techniques can help to local fisherman and fishery organizations to observe fishery resources

    Risk assessment across life cycle phases for small and medium software

    Get PDF
    Risk is labelled as an undesirable event that is encountered by every project irrespective of industry. Most software projects fail to meet the planned targets, i.e., scope, time, cost and quality. Software projects faced a wide range of risks and all risks cannot be dealt with the same priority. Risk can be prioritized by the probability of its occurrence and its impact. Therefore, risk assessment is required to highlight and prioritize serious risks. However, a very few researches targeted risk assessment faced by small and medium software projects. This research performs a risk assessment and highlighted serious risks faced by professionals working on small and medium software projects by documenting probability and impact. The chances of success of software projects can be increased by performing a proper risk assessment. The risks are identified by exploring and reviewing the existing literature. The identified risks are grouped by life cycle phases. This research utilizes a questionnaire-based approach to record the response of 163 software professionals working in Pakistan software industry. SPSS is used for data management and for performing statistical analysis. Probability and impact of each risk are measured to highlight the potential risks. The results concluded that the severity level of the majority of risks faced by small and medium software projects in Pakistan software industry is significant and high. The success of every project matters a lot for the progress of the organizations working on a small and medium level. Therefore, this research guide professionals and organizations to consider and prioritize the risk faced while working on small and medium software projects to increase the chances of the project's success

    Descriptive Analysis of Human Emotions Based on Eye pupils

    Get PDF
    Facial emotional expressions are viewed as the most descriptive way to understand the human’s state of temperament during confronting communication. In this work numerous statistical approaches have been applied on human eye pupil with static images of Chicago face dataset (CFD) to analyze and classify the considered categories for emotions which are Happy, Fear, Anger and Neutral. The aim of this study is to develop the specific architecture for image processing domain after applying different enhancement techniques on human eye pupil for analysis & recognition of the facial expressions. This work is divided into three phases initially in the first phase data preprocessing is performed to prepare according to the requirement of work and also the color images are converted in to negative by applying the pixel intensity controlled mechanism. Second phase define the boundary to compute the feature by using Circular Hough Transform algorithm. Lastly statistical approaches are applied on extracted features to corporate the central point of pupil. This corporation the central point presents the effects of emotions. While comparing peoples of different Age groups it is concluded that pupil constricted on Anger at different levels on different age groups. If further it is discussed about cross cultural and gender wise comparison then Happy Emotion effects most and resulted towards dilated pupil same like that Anger emotion effects most on constricting the pupil size

    A Novel Hybrid GWO-LS Estimator for Harmonic Estimation Problem in Time Varying Noisy Environment

    Get PDF
    The power quality of the Electrical Power System (EPS) is greatly affected by electrical harmonics. Hence, accurate and proper estimation of electrical harmonics is essential to design appropriate filters for mitigation of harmonics and their associated effects on the power quality of EPS. This paper presents a novel statistical (Least Square) and meta-heuristic (Grey wolf optimizer) based hybrid technique for accurate detection and estimation of electrical harmonics with minimum computational time. The non-linear part (phase and frequency) of harmonics is estimated using GWO, while the linear part (amplitude) is estimated using the LS method. Furthermore, harmonics having transients are also estimated using proposed harmonic estimators. The effectiveness of the proposed harmonic estimator is evaluated using various case studies. Comparing the proposed approach with other harmonic estimation techniques demonstrates that it has a minimum mean square error with less complexity and better computational efficiency

    Profiling users' behavior, and identifying important features of review 'helpfulness'

    Get PDF
    The increasing volume of online reviews and the use of review platforms leave tracks that can be used to explore interesting patterns. It is in the primary interest of businesses to retain and improve their reputation. Reviewers, on the other hand, tend to write reviews that can influence and attract people’s attention, which often leads to deliberate deviations from past rating behavior. Until now, very limited studies have attempted to explore the impact of user rating behavior on review helpfulness. However, there are more perspectives of user behavior in selecting and rating businesses that still need to be investigated. Moreover, previous studies gave more attention to the review features and reported inconsistent findings on the importance of the features. To fill this gap, we introduce new and modify existing business and reviewer features and propose a user-focused mechanism for review selection. This study aims to investigate and report changes in business reputation, user choice, and rating behavior through descriptive and comparative analysis. Furthermore, the relevance of various features for review helpfulness is identified by correlation, linear regression, and negative binomial regression. The analysis performed on the Yelp dataset shows that the reputation of the businesses has changed slightly over time. Moreover, 46% of the users chose a business with a minimum of 4 stars. The majority of users give 4-star ratings, and 60% of reviewers adopt irregular rating behavior. Our results show a slight improvement by using user rating behavior and choice features. Whereas, the significant increase in R2 indicates the importance of reviewer popularity and experience features. The overall results show that the most significant features of review helpfulness are average user helpfulness, number of user reviews, average business helpfulness, and review length. The outcomes of this study provide important theoretical and practical implications for researchers, businesses, and reviewers

    Characterization of Toxic Metals in Tobacco, Tobacco Smoke, and Cigarette Ash from Selected Imported and Local Brands in Pakistan

    Get PDF
    In this study, concentrations of Cd, Ni, Pb, and Cr were determined in tobacco, tobacco smoke-condensate, and cigarette ash for selected brands used in Pakistan. Smoking apparatus was designed for metal extraction from cigarette smoke. Samples were digested through microwave digester and then analyzed by flame atomic absorption spectrophotometer (FAAS). Higher concentration of Ni was detected in imported brands than the counterparts in the local brands. Pb levels were however higher in local brands while significant concentration of Cd was observed in both brands. For Cr, the level in tobacco of local brands was higher than their emitted smoke, whereas imported brands showed higher level in smoke than in tobacco. The cigarette ash retained 65 to 75% of the metal and about 25 to 30% went into the body. While this study revealed the serious requirement to standardize the manufacturing of tobacco products, more importantly is the urgent need for stronger enforcements to put in place to alert the general population about the hazardous effects of cigarettes and the health risks associated with these toxic metals

    Investigation of the cardiac depressant effect of Caralluma tuberculate N.E.Br on isolated rabbit heart

    Get PDF
    Purpose: To investigate the histopathological and cardiac depressant effect of the aqueous methanol extract of Caralluma tuberculata N.E. Br (AMECT) (family: Asclepiadaceae)’ and to determine if there is a scientific basis for its cardiovascular diseases-related folkloric use. Methods: The effect of AMECT in different concentrations ranging from 0.00001 to 1.0 mg/mL were evaluated in isolated perfused rabbit heart to assess their effect on the force of contraction and heart rate using Langendorff’s apparatus. Atropine and adrenaline were used to identify the underlying mechanism of response produced by AMECT. The extract was studied for its possible mechanism in the absence and presence of atropine and adrenaline. In addition, sub-chronic toxicity and histopathological study of heart tissues in rats were assessed by administering 500 mg/kg of extract. Results: At all concentrations, AMECT produced significant (p < 0.001) negative ionotropic and negative chronotropic effects. The most significant effect was observed at 0.001 mg/mL and higher concentrations hence 0.001 mg/mL was selected for further studies. Pre-incubation with atropine did not significantly inhibit the effects of AMECT. However, AMECT significantly (p < 0.01) blocked the cardiac stimulant effect of adrenaline. In the histopathological studies, AMECT did not produce any significant cellular changes or signs of toxicity in the sub-chronic toxicity study. Conclusion: The cardiac-depressant responses of AMECT may involve the β-adrenergic receptors in the myocardium of isolated rabbit heart thus confirming the rationale for its use in ethnomedicine for cardiac diseases

    The GASA Gene Family in Cacao (Theobroma cacao, Malvaceae): Genome Wide Identification and Expression Analysis

    Get PDF
    The gibberellic acid-stimulated Arabidopsis (GASA/GAST) gene family is widely distributed in plants and involved in various physiological and biological processes. These genes also provide resistance to abiotic and biotic stresses, including antimicrobial, antiviral, and antifungal. We are interested in characterizing the GASA gene family and determining its role in various physiological and biological process in Theobroma cacao. Here, we report 17 tcGASA genes distributed on six chromosomes in T. cacao. The gene structure, promoter region, protein structure and biochemical properties, expression, and phylogenetics of all tcGASAs were analyzed. Phylogenetic analyses divided tcGASA proteins into five groups. Among 17 tcGASA genes, nine segmentally duplicating genes were identified which formed four pairs and cluster together in phylogenetic tree. Differential expression analyses revealed that most of the tcGASA genes showed elevated expression in the seeds (cacao food), implying their role in seed development. The differential expression of tcGASAs was recorded between the tolerant and susceptible cultivars of cacao, which indicating their possible role as fungal resistant. Our findings provide new insight into the function, evolution, and regulatory system of the GASA family genes in T.cacao and may suggest new target genes for development of fungi-resistant cacao varieties in breeding programs
    • …
    corecore