1,132 research outputs found

    Further Refining Swampland dS Conjecture in Mimetic f(G) Gravity

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    Mimetic gravity analysis has been studied as a theory in various types of general relativity extensions, such as mimetic f(R) gravity, mimetic f(R, T) gravity, mimetic f(R, G) gravity, etc., in the literature. This paper presents a set of equations arising from mimetic conditions and studies cosmic inflation with a combination of mimetic f(G) gravity and swampland dS conjectures. We analyze and evaluate these results. Therefore, we first thoroughly introduce the mimetic f(G) gravity and calculate some cosmological parameters such as the scalar spectral index, the tensor-to-scalar ratio, and the slow-roll parameters. Also, we investigate the potential according to the mimetic f(G) gravity. Then we will challenge the swampland dS conjectures with this condition. By expressing the coefficient of swampland dS conjectures viz C1C_{1} and C2C_2 in terms of nsn_{s} and rr, we plot some figures and determine the allowable range for each of these cosmological parameters and these coefficients, and finally, compare these results with observable data such as Planck and BICEP2/Keck array data. We show C1C_{1} and C2C_2 are not O(1)\mathcal{O}(1), so the refining swampland dS conjecture is not satisfied for this inflationary model. Then we examine it with further refining swampland dS conjecture, which has a series of free parameters such as a,b>0a,b>0, q>2q>2, and a+b=1a+b=1. By adjusting these parameters, the compatibility of the mentioned conjecture with the inflationary model can be discussed. We determine the further refining swampland dS conjecture is satisfied. when a<11.00489=0.99513a < \frac{1}{1.00489}=0.99513, we can always find aa, bb and qq whose value is larger than 2, viz for q=2.4q=2.4, we find 0.99185a<10.99185\leq a < 1, which we can choose a=0.99235a=0.99235 according to the condition a<0.99513a < 0.99513. Also we know b=1ab=1-a, so we will have 10.99235=0.00765>01-0.99235=0.00765 > 0.Comment: 25 pages, 5 figures. Accepted for publication in International Journal of Modern Physics D (This work is dedicated to the memory of Prof Farhad Darabi

    Persian Pūlād Production: Chāhak Tradition

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    Crucible steel has fascinated scientists for over a century, but the study of its production is a fairly new field of research. Publications so far focus on archaeological sites from Central Asia (9th–12th centuries CE), India and Sri Lanka (mostly 17th century CE onwards). However, the development and spread of crucible steel-making is yet to be re-constructed to its full extent. It has been long suspected that the origins of this sophisticated technology potentially are to be found in Persia, modern day Iran, yet no archaeological evidence for this has been published so far. Several historical manuscripts provide some information on this technology and relate it to production centres in Persia. This article reports archaeological evidence for Persian crucible steel production, based on the medieval site of Chāhak in Central Iran, in the context of selected historical documents. The Chāhak crucible fragments have distinctive features that had not been seen elsewhere, while some similarities with Central Asian crucibles are evident. Microstructure and elemental composition of different crucible fragments and slags were determined with optical microscope and SEM-EDS, providing information on the fabric of the crucibles, the slag composition and the metal which was produced by this process. This project attempts to open a new chapter in the study of crucible steel production by introducing the Chāhak tradition, comparing it to other Central Asian traditions of production. This may pave the way to track and study the origins of crucible steel production in the broader context of Central and Western Asia

    Decoherence Dynamics of Measurement-Induced Nonlocality and comparison with Geometric Discord for two qubit systems

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    We check the decoherence dynamics of Measurement-induced Nonlocality(in short, MIN) and compare it with geometric discord for two qubit systems. There are quantum states, on which the action of dephasing channel cannot destroy MIN in finite or infinite time. We check the additive dynamics of MIN on a qubit state under two independent noise. Geometric discord also follows such additive dynamics like quantum discord. We have further compared non-Markovian evolution of MIN and geometric discord under dephasing and amplitude damping noise for pure state and it shows distinct differences between their dynamics.Comment: 11 pages, 10 figures, Revte

    An analysis of housing livability in Karaj with attitude social justice

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    Objective: Housing, in the sense the term of 'shelter', is the most basic and vital need of any living beings in nature. Housing is one of the most important sectors of development in a society that recognizing and assessing its status and unprosperous in the form of the social justice depends on identifying and analyzing the influencing factors. Likewise, the Promotion of affordable housing and also, increasing the choise of suitable housing options for all people, is one of the main goals of viability Methods: Therefore, the purpose of the research is to investigate the housing viability for achieving to viability of cities in social justice’s shadow. The type of research is applied – developmental, and its method is descriptive-analytical. The gathering of data is documentary and research indicators were collected from the Population and Housing Census of Karaj districts in 2016. Results:The analysis of the data has been displayed by using TODIM multi-criteria decision making model and finally, by integrating the indicators into the relevant model and formation its layers in GIS software and having districts map. The results show that Karaj 8th district, in comparison to others, is ranked first in terms of housing viability indicators, and the other districts are in the next levels with little difference. The findings also indicate different levels of viability within each district, so it is indicating a discontinuity between neighborhoods in districts. Conclusion: This discontinuity indicates that neighborhoods do not have equal facilities and amenities, so that undermine the social justice at them

    Is metabolic syndrome considered to be a risk factor for gastroesophageal reflux disease (non-erosive or erosive esophagitis)?: A systematic review of the evidence

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    Context: The incidences of both gastroesophageal reflux disease (GERD) and metabolic syndrome (MetS) have increased in recent years, and it has been suggested that there is a probable association between the two. The aim of this review is to clarify whether or not MetS is a risk factor for the incidence of GERD. Evidence Aquisition: We searched the PubMed, ProQuest, Ovid, Science Direct, and Google Scholar databases up to February 2015 regarding the relationship between GERD and MetS as found in observational studies. Any studies that evaluated the association between the components of MetS and GERD, as well as any studies examining the association of MetS with Barrett�s esophagus or esophageal carcinoma, were excluded. Results: Thirteen studies met the eligibility criteria. The results of nine studies suggested that there was a higher prevalence of MetS among patients with GERD (P < 0.05) and, thus, it could be considered as an independent risk factor for the incidence of GERD. However, in the one study was not observed significant association between GERD and MetS (P = 0.71). Two studies in which the prevalence of GERD was compared between individuals with and without MetS showed a higher prevalence of GERD in patients with MetS (P < 0.05). However, this finding was not observed in a similar study conducted among female participants, which reported that the different types of MetS were not important factors with regard to the prevalence of erosive esophagitis (P = Not significant). Conclusions: It can be concluded that MetS may increase the risk of GERD. Consequently, there might be potential benefits to treating the metabolic abnormalities in these patients. © 2016, Iranian Red Crescent Medical Journal

    Cashmere quality of Raeini goats kept by nomads in Iran

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    The income of the nomads in Kerman Province depends mainly on Raeini goats that produce meat, milk and cashmere. This paper assesses the cashmere quality and its variation in Raeini herds to determine the scope for improvement. In April 2010 fleece weights (FW) and midside fleece samples were taken from a total of 686 male and female cashmere goats of 1, 2 and 3 years of age belonging to 29 herds. The herds were randomly chosen in the summer grazing area of nomads within 20 km of the city of Baft, province of Kerman, South of Iran, the main cashmere producing area in Iran. Cashmere yield (CY) was determined from the weight of dehaired cashmere to weight of shorn fiber. Cashmere fibers were analyzed using an OFDA instrument. A general mixed linear model including sex, age and sex by age interaction as fixed effects and herd as random effect was used to analyze the data and measure the relationships between different cashmere characteristics and fleece attributes. The overall means ± standard deviations were for fleece weights (FW) 507 ± 183 g, cashmere yield (CY) 56.5 ± 12.2%, mean fiber diameter (MFD) 19.7 ± 1.5 μm, fiber diameter standard deviation (FDSD) 4.5 ± 0.6 μm, fiber curvature (FC) 62.9 ± 8.5°/mm and staple length (SL) 54.2 ± 7.0 mm, respectively. Herd effect was significant for all traits except for SL and sex by age effect was only significant for MFD. One year old males and females had finer cashmere than older goats. FW and FDSD were higher in males and CY and FC was higher in young animals. Pearson correlation between MFD and FC, FDSD and MFD, MFD and FW was −0.647, 0.399 and 0.211 respectively. Raeini cashmere is white, has an excellent SL and FC but is relatively coarse. Given the differences between and within herds there seems to be substantial scope to improve the commercial value of Raeini cashmere.Fil: Ansari-Renani, Hamid R. Animal Science Research Institute; IránFil: Mueller, Joaquin Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Rischkowsky, Barbara. International Center for Agricultural Research in the Dry Areas; SiriaFil: Seyed Momend, S.M. Agriculture and Natural Resources Research Center; IránFil: Alipour, O. Livestock Office of Agriculture Department of Baft; IránFil: Ehsani, M. Agriculture and Natural Resources Research Center; IránFil: Moradi, Sepehr. University of Zanjan. Agriculture College. Animal Science Department; Irán. Animal Science Research Institute; Irán

    Exact symmetry breaking ground states for quantum spin chains

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    We introduce a family of spin-1/2 quantum chains, and show that their exact ground states break the rotational and translational symmetries of the original Hamiltonian. We also show how one can use projection to construct a spin-3/2 quantum chain with nearest neighbor interaction, whose exact ground states break the rotational symmetry of the Hamiltonian. Correlation functions of both models are determined in closed form. Although we confine ourselves to examples, the method can easily be adapted to encompass more general models.Comment: 4 pages, RevTex. 4 figures, minor changes, new reference

    Phantom Mimicry on the Normal Branch of a DGP-inspired Braneworld Scenario with Curvature Effect

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    It has been shown recently that phantom-like effect can be realized on the normal branch of the DGP setup without introduction of any phantom matter neither in the bulk nor on the brane and therefore without violation of the null energy condition. It has been shown also that inclusion of the Gauss-Bonnet term in the bulk action modifies this picture via curvature effects. Here, based on the Lue-Starkman conjecture on the dynamical screening of the brane cosmological constant in the DGP setup, we extend this proposal to a general DGP-inspired f(R,ϕ)f(R,\phi) model that stringy effects in the ultra-violet sector of the theory are taken into account by inclusion of the Gauss-Bonnet term in the bulk action. We study cosmological dynamics of this setup, especially its phantom-like behavior and possible crossing of the phantom divide line especially with a non-minimally coupled quintessence field on the brane. In this setup, scalar field and curvature quintessence are treated in a unified framework.Comment: 25 Figures, To appear in MPL
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