1,744 research outputs found

    A New Model of Quintessence Compact Stars in Rastall Theory of Gravity

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    In the present work, we study a new model of anisotropic compact stars in the regime of Rastall theory. To solve the Rastall field equations we have used the Karori and Barua (KB) ansatz along with the quintessence dark energy characterized by a parameter ωq\omega_{q} with −1<ωq<−13-1<\omega_{q}<-\frac{1}{3}. We present a comparative study to demonstrate the physical acceptance of our proposed model. We compare the numerical values of physical parameters obtained from our model with those of general relativity (GRGR) model given by Bhar \cite{1} and observe that our model is more compatible (for some chosen values of Rastall dimensionless parameter γ=κλ\gamma=\kappa\lambda) with observational data than GRGR model. For this analysis we have consider four different compact stars, SAXJ1808−3658(SSI)SAX J1808-3658 (SSI), 4U1820−304U 1820-30, VelaX−12Vela X-12 and PSRJ1416−2230PSR J1416-2230 with radii 7.07km7.07km, 10km10km, 9.99km9.99km and 10.3km10.3km, respectively. In this investigation we also present some physical aspects of the proposed model necessary to check the validity of the model and inferred that our model is acceptable physically and geometrically.Comment: 20 pages, 16 figures, 8 tables, Accepted for Publication in Eur. Physical Journal

    Mass transfer efficiency of a tall and low plate free area liquid pulsed sieve-plate extraction column

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    Acknowledgements The authors would like to acknowledge Chakwal group of industries for funding the project. Ms. Madiha, Ms. Zona, Mr. Sohaib, Mr. Abdullah, Mr. Mudassar, and Mr. Salahuddin also deserve our acknowledgements for their assistance in different ways.Peer reviewedPublisher PD

    Nonlinear analysis of drainage systems to examine surface deformation: an example from Potwar Plateau (Northern Pakistan)

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    We devise a procedure in order to characterize the relative vulnerability of the Earth's surface to tectonic deformation using the geometrical characteristics of drainage systems. The present study focuses on the nonlinear analysis of drainage networks extracted from Digital Elevation Models in order to localize areas strongly influenced by tectonics. We test this approach on the Potwar Plateau in northern Pakistan. This area is regularly affected by damaging earthquakes. Conventional studies cannot pinpoint the zones at risk, as the whole region is characterized by a sparse and diffuse seismicity. Our approach is based on the fact that rivers tend to linearize under tectonic forcing. Thus, the low fractal dimensions of the Swan, Indus and Jehlum Rivers are attributed to neotectonic activity. A detailed textural analysis is carried out to investigate the linearization, heterogeneity and connectivity of the drainage patterns. These textural aspects are quantified using the fractal dimension, as well as lacunarity and succolarity analysis. These three methods are complimentary in nature, i.e. objects with similar fractal dimensions can be distinguished further with lacunarity and/or succolarity analysis. We generate maps of fractal dimensions, lacunarity and succolarity values using a sliding window of 2.5 arc minutes by 2.5 arc minutes (2.5'&amp;times;2.5'). These maps are then interpreted in terms of land surface vulnerability to tectonics. This approach allowed us to localize several zones where the drainage system is highly structurally controlled on the Potwar Plateau. The region located between Muree and Muzaffarabad is found to be prone to destructive events whereas the area westward from the Indus seems relatively unaffected. We conclude that a nonlinear analysis of the drainage system is an efficient additional tool to locate areas likely to be affected by massive destructing events affecting the Earth's surface and therefore threaten human activities

    Measuring the BDARX architecture by agent oriented system a case study

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    Distributed systems are progressively designed as multi-agent systems that are helpful in designing high strength complex industrial software. Recently, distributed systems cooperative applications are openly access, dynamic and large scales. Nowadays, it hardly seems necessary to emphasis on the potential of decentralized software solutions. This is because the main benefit lies in the distributed nature of information, resources and action. On the other hand, the progression in multi agent systems creates new challenges to the traditional methodologies of fault-tolerance that typically relies on centralized and offline solution. Research on multi-agent systems had gained attention for designing software that operates in distributed and open environments, such as the Internet. DARX (Dynamic Agent Replication eXtension) is one of the architecture which aimed at building reliable software that would prove to be both flexible and scalable and also aimed to provide adaptive fault tolerance by using dynamic replication methodologies. Therefore, the enhancement of DARX known as BDARX can provide dynamic solution of byzantine faults for the agent based systems that embedded DARX. The BDARX architecture improves the fault tolerance ability of multi-agent systems in long run and strengthens the software to be more robust against such arbitrary faults. The BDARX provide the solution for the Byzantine fault tolerance in DARX by making replicas on the both sides of communication agents by using BFT protocol for agent systems instead of making replicas only on server end and assuming client as failure free. This paper shows that the dynamic behaviour of agents avoid us from making discrimination between server and client replicas

    Blood Glucose Responses to Type, Intensity, Duration, and Timing of Exercise

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    [First Paragraph] The Big Blue Test (BBT) is an annual initiative by the Diabetes Hands Foundation to raise awareness of the importance of physical activity in managing diabetes. Individuals with diabetes voluntarily exercise and record self-monitored blood glucose levels. During the 2012 BBT, 5,157 diabetic participants (~90% insulin users) anonymously entered exercise type, intensity, duration, time elapsed since last meal, and blood glucose readings before and after one or more bouts of exercise separately through www.BigBlueTest.org or an Iphone app

    Scrutinizing human MHC polymorphism:supertype analysis using Poisson-Boltzmann electrostatics and clustering

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    Peptide-binding MHC proteins are thought the most variable proteins across the human population; the extreme MHC polymorphism observed is functionally important and results from constrained divergent evolution. MHCs have vital functions in immunology and homeostasis: cell surface MHC class I molecules report cell status to CD8+ T cells, NKT cells and NK cells, thus playing key roles in pathogen defence, as well as mediating smell recognition, mate choice, Adverse Drug Reactions, and transplantation rejection. MHC peptide specificity falls into several supertypes exhibiting commonality of binding. It seems likely that other supertypes exist relevant to other functions. Since comprehensive experimental characterization is intractable, structure-based bioinformatics is the only viable solution. We modelled functional MHC proteins by homology and used calculated Poisson-Boltzmann electrostatics projected from the top surface of the MHC as multi-dimensional descriptors, analysing them using state-of-the-art dimensionality reduction techniques and clustering algorithms. We were able to recover the 3 MHC loci as separate clusters and identify clear sub-groups within them, vindicating unequivocally our choice of both data representation and clustering strategy. We expect this approach to make a profound contribution to the study of MHC polymorphism and its functional consequences, and, by extension, other burgeoning structural systems, such as GPCRs

    Revisiting the threshold effect of remittances on total factor productivity growth in South Asia: a study of Bangladesh and India

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    Both Bangladesh and India are among the top recipient of remittances in absolute terms. However, in relative terms – remittances as a per cent of GDP – the two countries stand at 6.1% and 2.8%, respectively, well below the levels of the top 10 recipients. In this article, we explore the effect of remittances on the total factor productivity (TFP) growth considering Bangladesh and India, as reference countries over the periods 1980–2012 and 1977–2012, respectively. We examine the presence of a long-run association between remittances and TFP using a number of tests. The results indicate that remittances have threshold effects on TFP growth in both countries. Despite the two countries receiving substantial amount of remittances, we note that Bangladesh has a U-shaped relationship whereas India has an inverted U-shaped relationship with TFP growth. For Bangladesh, a minimum threshold of remittances (% GDP) is 5.3% and for India, a tipping point of remittances (% GDP) is at 1.8%. The causality tests confirm a bidirectional effect, which implies that remittances and TFP growth are mutually reinforcing. Interestingly, while the two economies have similar remittances impact in regards to causality, the study highlights two different tipping points of remittances

    Exploring the effect of ICT and tourism on economic growth: a study of Israel

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    In this paper, we explore the impact of information and communications technology (ICT) and tourism on per worker output over the period 1960–2016 by using an augmented Solow (Quart J Econ 70(1): 65–94, 1956) framework estimated through the autoregressive distributed lag procedure for cointegration (Pesaran et al. in J Appl Econ 16(3):289–326, 2001). The results show that mobile cellular subscriptions (measure of ICT pervasiveness) and visitor arrivals as a percent of workers (measure of tourism) are cointegrated and positive, however, only ICT is statistically significant in the long-run. The long-run elasticity coefficient of ICT and tourism is 0.03 and 0.05, respectively. We note a unidirectional causality from ICT to output per worker, from tourism to output per worker, from capital per worker to tourism, and from ICT to tourism. From the results, we emphasize that focusing on technology advancement and tourism expansion will provide the necessary support for economic growth in the country

    Influence of anodizing process on fatigue life of a machined aluminium alloy

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    In order to investigate the coupled effects of machining and anodizing processes on fatigue life of alloy 7010-T7451, a series of rotating bending fatigue tests were conducted at 60Hz. In the as machined condition, test results showed that fatigue life is surface roughness dependent and that fatigue life decreases with an increase in surface roughness and this effect is found to be more pronounced in high cycle fatigue where major portion of fatigue life is consumed in nucleating the cracks. Effects of pretreatments, like degreasing and pickling employed prior to anodizing, on fatigue life of the given alloy were also studied. Results demonstrated that degreasing showed no change in fatigue life while pickling had negative impact on fatigue life of specimens. The small decrease in fatigue life of anodized specimens as compare to pickled specimens is attributed to brittle and microcracking of the coating. Scanning electron microscopic (SEM) examination revealed multi-site crack initiation for the pickled and anodized specimens. SEM examination showed that pickling solution attacked the grain boundaries and intermetallic inclusions present on the surface resulting in pits formation. These pits are of primary concern with respect to accelerated fatigue crack nucleation and subsequent anodized coating formation

    Survey of aflatoxins in chillies from Pakistan produced in rural, semi-rural and urban environments

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    Chilli peppers from Pakistan are consumed locally and also exported. Their quality is compromised by aflatoxins (AF) contamination. AF in chillies from rural, semi-rural and urban areas of the Punjab region of Pakistan were determined. Twenty-three (52.3%), 22 (50%) and 29 (65.9%) samples from rural, semi-rural and urban areas respectively, contained levels of aflatoxins which exceeded the European Union limits of >5 µg kg-1 for AFB1 and >10 µg kg-1 for total AF that apply to spices. Mean values for AFB1 in ground samples were 23.8, 14.8 and 14.0 µg kg-1 for rural, semi-rural and urban areas, respectively. Mean total AF in ground samples were 27.7, 17.7 and 16.2 µg kg-1 from equivalent locations. Eleven (50%), 12 (54.5%) and 14 (63.6%) whole samples from rural, semi-rural and urban areas, respectively, contained total levels of AF that exceeded European Union limits. The data indicate that individual localities have particular problems. In conclusion, the concentrations were often greater than the statutory limits set by the European Union.The authors acknowledge the financial support of the Higher Education Commission, Pakistan, under Indigenous PhD fellowship 5000 batch-III (Grant Number 063-00445-Ps3-047). R.R.M.P. is grateful for the FCT framework position: Commitment to Science (C2008-UMIN-HO-CEB-2)
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