Investigation of heavy metals in the Persian Gulf pearl oyster Pinctada radiata by using atomic absorption spectroscopy

Bioaccumulation of seven heavy metals (Zn, Cu, Fe, Cd, Pb, Ni, Mn) were determined in the Persian Gulf pearl oyster "Pinctada radiata" collected from major pearl oyster beds of Lavan and Handurabi Islands and Nakhiloo port during six months, winter of 1994 and spring of 1995, by spectroscopy, considering their environmental condition such as : salinity, pH, dissolved oxygen and transparency. Three ways analysis of variance and mean comparison tests, have been used to determine the relationship between concentration of metals and factors including time sampling, sites and size of samples

Governance gaps in eradicating forced labor: from global to domestic supply chains

A growing body of scholarship analyzes the emergence and resilience of forced labor in developing countries within global value chains (GVCs). However, little is known about how forced labor arises within domestic supply chains concentrated within national borders, producing products for domestic consumption. We conduct one of the first studies of forced labor in domestic supply chains, through a cross-industry comparison of the regulatory gaps surrounding forced labor in the United Kingdom. We find that understanding the dynamics of forced labor in domestic supply chains requires us to conceptually modify the GVC framework to understand similarities and differences across these contexts. We conclude that addressing the governance gaps that surround forced labor will require scholars and policymakers to carefully refine their thinking about how we might design operative governance that effectively engages with local variation

Shear resistance of SFRSCC short-span beams without transversal reinforcements

Corrosion of steel reinforcements, especially stirrups, is considered as one of the most common reasons that shorten the service life of the reinforced concrete structures. This study aims to replace the stirrups of the beams by means of a tailor made steel fiber reinforced self-compacting concrete (SFRSCC). A hybrid flexural reinforcement system was used for all these beams, composed of glass fiber reinforced polymer (GFRP) rebars placed near to the outer surface of the tensile zone and steel reinforcements positioned with higher SFRSCC cover to be protected against the corrosion, which is considered another strategy for enhancing the durability and attending fire issues in terms of safety at ultimate limit states. The effectiveness of varying the prestressing force applied to GFRP bars to improve the shear capacity and failure mode of the designed elements is evaluated. By considering the obtained experimental results, the predictive performance of some analytical formulations for the shear resistance of fiber reinforced concrete beams was assessed. All formulations demonstrate acceptable accuracy for design purposes, but the one proposed by CEB-FIP Model Code 2010 predicts more conservative shear resistance.European Regional Development Fund (FEDER) - “Inotec”, with reference number 23024Portuguese Foundation for Science and Technology (FCT) - “SlabSys-HFRC”, with reference PTDC/ECM/120394/201

Effect of fiber dosage and prestress level on shear behavior of hybrid GFRP-steel reinforced concrete I-shape beams without stirrups

Corrosion of steel reinforcements embedded in concrete elements is generally known as one of the most common reasons that shorten the service life of the structures. The present study aims to contribute in overcoming this problem by replacing steel stirrups as shear reinforcement of concrete beams using a steel fiber reinforced self-compacting concrete (SFRSCC). In the present research the potential of SFRSCC for improving the shear resistance of the beams without stirrups is explored. In order to further reduce the risk of corrosion in this type of beams, a hybrid system of flexural reinforcement composed of a steel strand and GFRP rebars is applied and properly arranged in order to assure a relatively thick concrete cover for the steel reinforcement. The GFRP bars are placed with the minimum cover thickness for providing the maximum internal arm and, consequently, mobilizing efficiently their relatively high tensile strength. The effectiveness of applying different dosages of steel fibers and varying the prestress force to improve the shear behavior of the designed beam are evaluated. By considering the obtained experimental results, the predictive performance of a constitutive model (plastic-damage multidirectional fixed smeared crack model) implemented in a FEM-based computer program, as well as the one from three analytical formulations for estimating shear resistance of the developed beams were assessed. The FEM-based simulations have provided a good prediction of the deformational response and cracking behavior of the tested beams. All the analytical formulations demonstrated acceptable accuracy for design purposes, but the one proposed by CEB-FIP Modal Code 2010 predicts more conservative shear resistance.The first and second authors, respectively, acknowledge the research grant in the ambit of the project “UrbanCrete”, with reference number of 30367, supported by the European Regional Development Fund (FEDER), and “SlabSys-HFRC”, with reference PTCD/ECM/120394/2010, supported by the Portuguese Foundation for Science and Technology (FCT). The authors also thank the collaboration of the following companies: Tensacciaci in the name of Eng. F. Pimenta for the assistance on the application of prestress reinforcements, Sireg and Schoeck for providing the GFRP rebars, Casais to manufacture the moulds, Exporplas for supplying the polypropylene fibers, Secil/Unibetão for providing the Cement, BASF for supplying the superplasticizer and CiviTest for collaborating in producing the specimens

Role of mindfulness, psychological flexibility and integrative self-knowledge on psychological well-being among the university students

Background: Studies has shown the effect on environmental conditions on psychological well-being. In this regard, psychological characteristics have an important role. This study aimed to investigate the role of mindfulness, psychological flexibility and integrative self -knowledge amonge the university students. Material and Methods: This cross-sectional study was performed on the students of Kashan university of medical sciences (n=300) and based on quota sampling, a number of students (n=241) were selected based on the faculty and the major of the study. The administered tools were Ryff scale of psychological well-being (RSPWB-18), mindfulness (MAAS), acceptance and actions (AAQ-II) questionnaires and integrative self-knowledge scale (ISKS). Finally the data were analyzed using correlation and stepwise regression. Results: Pearson correlation disclosed a positive and considerable relation between mindfulness, integrative self-knowledge, psychological flexibility and psychological well-being. In addition, the findings showed significant role of mindfulness, integrative self-knowledge and psychological flexibility to predict the psychological well-being of the students; so these variables can predict 21 of psychological wellbeing changes. Conclusion: This study disclosed that the mindfulness, psychological flexibility and integrative self -knowledge can in part specify the variance of psychological well-being

Plastic-damage smeared crack model to simulate the behaviour of structures made by cement based materials

This work proposes a constitutive model to simulate nonlinear behaviour of cement based materials subjected to different loading paths. The model incorporates a multidirectional fixed smeared crack approach to simulate crack initiation and propagation, whereas the inelastic behaviour of material between cracks is treated by a numerical strategy that combines plasticity and damage theories. For capturing more realistically the shear stress transfer between the crack surfaces, a softening diagram is assumed for modelling the crack shear stress versus crack shear strain. The plastic damage model is based on the yield function, flow rule and evolution law for hardening variable, and includes an explicit isotropic damage law to simulate the stiffness degradation and the softening behaviour of cement based materials in compression. This model was implemented into the FEMIX computer program, and experimental tests at material scale were simulated to appraise the predictive performance of this constitutive model. The applicability of the model for simulating the behaviour of reinforced concrete shear wall panels submitted to biaxial loading conditions, and RC beams failing in shear is investigated.The authors wish to acknowledge the FCT financial support provided by the Portuguese Foundation for Science and Technology in the scope of the SlabSys-HFRC research project, with reference PTDC/ECM/120394/2010

Gingival neoplasm presenting as an ossifying epulis in a parrot cichlid fish (Hoplarchus psittacus)

This report describes the histopathological features of an ossifying epulis, measuring 1.5 × 1 × 1 cm in length, width and height, respectively, on the lingual surface of the lower jaw of a 2.5 year-old parrot cichlid (Hoplarchus psittacus) from a commercial aquarium. The tumor had appeared in the oral cavity three months prior to its introduction to the laboratory for diagnosis. Grossly, the neoplastic mass was pale-tan with a shiny, smooth surface and coalescing areas of hemorrhage. Microscopically, the overlying epithelium was hyperplastic and extended deeply into the underlying stroma. The stroma consisted of well vascularized collagenous tissue and neoplastic fibroblasts associated with irregular cords and islands of mineral deposition as dentin-like materials confirmed by Masson's trichrome and Goldner's trichrome staining

A microscopic theory of gauge mediation

We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.Comment: 24 pages, 2 figures, accepted to JHEP for publicatio

Anomalous Dimensions and Non-Gaussianity

We analyze the signatures of inflationary models that are coupled to strongly interacting field theories, a basic class of multifield models also motivated by their role in providing dynamically small scales. Near the squeezed limit of the bispectrum, we find a simple scaling behavior determined by operator dimensions, which are constrained by the appropriate unitarity bounds. Specifically, we analyze two simple and calculable classes of examples: conformal field theories (CFTs), and large-N CFTs deformed by relevant time-dependent double-trace operators. Together these two classes of examples exhibit a wide range of scalings and shapes of the bispectrum, including nearly equilateral, orthogonal and local non-Gaussianity in different regimes. Along the way, we compare and contrast the shape and amplitude with previous results on weakly coupled fields coupled to inflation. This signature provides a precision test for strongly coupled sectors coupled to inflation via irrelevant operators suppressed by a high mass scale up to 1000 times the inflationary Hubble scale.Comment: 40 pages, 10 figure

Application of plastic-damage multidirectional fixed smeared crack model in analysis of RC structures

This paper describes a plasticity-damage multidirectional fixed smeared cracking (PDSC) model to simulate the failure process of concrete and reinforced concrete (RC) structures subjected to different loading paths. The model proposes a unified approach combining a multidirectional fixed smeared crack model to simulate the crack initiation and propagation with a plastic-damage model to account for the inelastic compressive behaviour of concrete between cracks. The smeared crack model considers the possibility of forming several cracks in the same integration point during the cracking process. The plasticity part accounts for the development of irreversible strains and volumetric strain in compression, whereas the strain softening and stiffness degradation of the material under compression are controlled by an isotropic strain base damage model. The theoretical aspects about coupling the fracture, plasticity, and damage components of the model, as well as the model appraisal at both material and structural levels, have been detailed in a former publication. This study briefly summarizes the model formulations, and is mainly dedicated to further explore the potentialities of the proposed constitutive model for the analysis of concrete and RC structures. The model is employed to simulate experimental tests that are governed by nonlinear phenomenon due to simultaneous occurrence of cracking and inelastic deformation in compression. The numerical simulations have predicted with good accuracy the load carrying capacity, ductility, crack pattern, plastic (compressive) zone, and failure modes of all types of structures analysed. The influence of the model parameters that simulate the nonlinear behaviour of concrete under tension and compression is analysed through a parametric study.Portuguese Foundation for Science and Technology in the scope of the SlabSys-HFRC research project, with reference PTDC/ECM/120394/201