Select toxic metals status of pregnant women with history of pregnancy complications in Benin City, South-South Nigeria.

Toxic metals are part of the most important groups of environmental pollutants that can bind to vital cellular components and interfere with their functions via inhalation, foods, water etc. The serum levels of toxic metals (lead, mercury, cadmium and arsenic) in pregnant women with history of pregnancy complications, pregnant women without history of pregnancy complication and non-pregnant women in Benin City, South – South Nigeria was investigated in this paper, with total of 135 healthy women comprising of 45 pregnant women with history of previous pregnancy complications, 45 pregnant women without history of pregnancy complications and 45 non-pregnant women without history of pregnancy complications (controls). Some demographic characteristics and 4ml of blood samples were obtained from each subject for the analysis of lead, mercury, cadmium and arsenic by standard methods. Pregnant women with history of pregnancy complications recorded a highly significant increase in the toxic metal (lead) mean value of 25.81μg/dl as against 23.70μg/dl for pregnant women without history of pregnancy complications and 11.23μg/dl for non-pregnant (control) women without history of pregnancy complications as well as significant increases in the mean values of other toxic metals (mercury, cadmium and arsenic) compared with controls (p<0.001). The selected toxic metals (Pb, Hg, Cd and As) may be involved in the development of pregnancy complications among pregnant women in Benin City, South– South Nigeria. Lead in particular may pose threat to mothers and fetuses as its mean values in the two groups of pregnant women were well above normal.

Peat humic substances enriched with nutrients for agricultural applications: Competition between nutrients and non-essential metals present in tropical soils

Improved agricultural productivity, and reduction of environmental impacts, require studies of the interactions between different soil components. Fertilizers marketed as "organic" or "natural", such as peats or humic substances (HS) extracted from peats, are enriched with macro and micronutrients that, according to the manufacturers, are released to the plant in accordance with its needs. This work investigates the complexation capacity of HS for macro and micronutrient metal species, considering the competition, for HS complexation sites, between non-essential metals (aluminium and lead), present in the soil, and the nutrients. Humic substances were found to possess strong affinities for Pb(II) and Al(III), forming stable complexes, with concomitant release of complexed nutrients. Although HS are already used commercially as organic fertilizers, further studies of methods of HS enrichment, aimed at avoiding losses, are highly desirable from environmental and economic perspectives. (C) 2009 Elsevier B.V. All rights reserved.

Mesh Adaption for Tracking Vortex Structures in OVERTURNS Simulation of the S-76 Rotor in Hover

The constant need to improve helicopter performance requires the optimization of existing and future rotor designs. A crucial indicator of rotor capability is hover performance, which depends on the near-body flow as well as the structure and strength of the tip vortices formed at the trailing edge of the blades. Computational Fluid Dynamics (CFD) solvers must balance computational expenses with preservation of the flow, and to limit computational expenses the mesh is often coarsened in the outer regions of the computational domain. This can lead to degradation of the vortex structures which compose the rotor wake. The current work conducts three-dimensional simulations using OVERTURNS, a three-dimensional structured grid solver that models the flow field using the Reynolds-Averaged Navier-Stokes equations. The S-76 rotor in hover was chosen as the test case for evaluating the OVERTURNS solver, focusing on methods to better preserve the rotor wake. Using the hover condition, various computational domains, spatial schemes, and boundary conditions were tested. Furthermore, a mesh adaption routine was implemented, allowing for the increased refinement of the mesh in areas of turbulent flow without the need to add points to the mesh. The adapted mesh was employed to conduct a sweep of collective pitch angles, comparing the resolved wake and integrated forces to existing computational and experimental results. The integrated thrust values saw very close agreement across all tested pitch angles, while the power was slightly over predicted, resulting in under prediction of the Figure of Merit. Meanwhile, the tip vortices have been preserved for multiple blade passages, indicating an improvement in vortex preservation when compared with previous work. Finally, further results from a single collective pitch case were presented to provide a more complete picture of the solver results.

Comparing simulation output accuracy of discrete event and agent based models: a quantitative approach

In our research we investigate the output accuracy of discrete event simulation models and agent based simulation models when studying human centric complex systems. In this paper we focus on human reactive behaviour as it is possible in both modelling approaches to implement human reactive behaviour in the model by using standard methods. As a case study we have chosen the retail sector, and here in particular the operations of the fitting room in the women wear department of a large UK department store. In our case study we looked at ways of determining the efficiency of implementing new management policies for the fitting room operation through modelling the reactive behaviour of staff and customers of the department. First, we have carried out a validation experiment in which we compared the results from our models to the performance of the real system. This experiment also allowed us to establish differences in output accuracy between the two modelling methods. In a second step a multi-scenario experiment was carried out to study the behaviour of the models when they are used for the purpose of operational improvement. Overall we have found that for our case study example both, discrete event simulation and agent based simulation have the same potential to support the investigation into the efficiency of implementing new management policies.

Inverse Spectral Methods in Acoustic Normal Mode Velocimetry of High Reynolds Number Spherical Couette Flows

Experimental geophysical fluid dynamics often examines regimes of fluid flow infeasible for computer simulations. Velocimetry of zonal flows present in these regimes brings many challenges when the fluid is opaque and vigorously rotating; spherical Couette flows with molten metals are one such example. The fine structure of the acoustic spectrum can be related to the fluid’s velocity field, and inverse spectral methods can be used to predict and, with sufficient acoustic data, mathematically reconstruct the velocity field. The methods are to some extent inherited from helioseismology. This work develops a Finite Element Method suitable to matching the geometries of experimental setups, as well as modelling the acoustics based on that geometry and zonal flows therein. As an application, this work uses the 60-cm setup Dynamo 3.5 at the University of Maryland Nonlinear Dynamics Laboratory. Additionally, results obtained using a small acoustic data set from recent experiments in air are provided.

Evaluating tests for convergence of economic series using Monte Carlo methods with an application to real GDP's per head.

Doutoramento em Economia.

X-ray fluorescence spectroscopic determination of heavy metals and trace elements in aerial parts of Origanum sipyleum L from Turkey

Purpose: To determine the heavy metal and trace element composition of the powdered aerial parts of Origanum sipyleum L. and its water extract. Methods: The heavy metal and trace elements content of the powdered plant material and 2 % aqueous extract were evaluated by x-ray fluorescence spectroscopy with silicon drift detector SDD at a resolution of 145 eV and 10,000 pulses. The process conditions were 0.1 g sample weight, process time of 300 s at a voltage of 25 kV and 50 kV, and at a current of 0.5 and 1.0 mA under helium atmosphere. Results: The major elements, K, Ca and Na, known as macronutrients, constituted 11990, 10490 and 970 ppm of the powdered drug and 8910, 2991 and 810 ppm of the water extract, respectively. Among other constituents, arsenic, lead and uranium levels were < 1, 2.1 and < 3 ppm, respectively, in the powdered material while in the aqueous extract, the levels were < 1, < 2 and 200 ppm, respectively. Conclusion: O. sipyleum is a potential source of macro- and micronutrients from which useful food additives and health supplements can be derived.

Stress based prediction of formability and failure in incremental sheet forming

A strain-based forming limit criterion is widely used in sheet-metal forming industry to predict necking. However, this criterion is usually valid when the strain path is linear throughout the deformation process [1]. Strain path in incremental sheet forming is often found to be severely nonlinear throughout the deformation history. Therefore, the practice of using a strain-based forming limit criterion often leads to erroneous assessments of formability and failure prediction. On the other hands, stress-based forming limit is insensitive against any changes in the strain path and hence it is first used to model the necking limit in incremental sheet forming. The stress-based forming limit is also combined with the fracture limit based on maximum shear stress criterion to show necking and fracture together. A derivation for a general mapping method from strain-based FLC to stress-based FLC using a non-quadratic yield function has been made. Simulation model is evaluated for a single point incremental forming using AA 6022-T43, and checked the accuracy against experiments. By using the path-independent necking and fracture limits, it is able to explain the deformation mechanism successfully in incremental sheet forming. The proposed model has given a good scientific basis for the development of ISF under nonlinear strain path and its usability over conventional sheet forming process as well.

Effects of low- versus high-fidelity simulations on the cognitive burden and performance of entry-level paramedicine students: a mixed-methods comparison trial using eye-tracking, continuous heart rate, difficulty rating scales, video observation and inte

INTRODUCTION: High-fidelity simulation-based training is often avoided for early-stage students because of the assumption that while practicing newly learned skills, they are ill suited to processing multiple demands, which can lead to "cognitive overload" and poorer learning outcomes. We tested this assumption using a mixed-methods experimental design manipulating psychological immersion. METHODS: Thirty-nine randomly assigned first-year paramedicine students completed low- or high-environmental fidelity simulations [low-environmental fidelity simulations (LFenS) vs. high-environmental fidelity simulation (HFenS)] involving a manikin with obstructed airway (SimMan3G). Psychological immersion and cognitive burden were determined via continuous heart rate, eye tracking, self-report questionnaire (National Aeronautics and Space Administration Task Load Index), independent observation, and postsimulation interviews. Performance was assessed by successful location of obstruction and time-to-termination. RESULTS: Eye tracking confirmed that students attended to multiple, concurrent stimuli in HFenS and interviews consistently suggested that they experienced greater psychological immersion and cognitive burden than their LFenS counterparts. This was confirmed by significantly higher mean heart rate (P < 0.001) and National Aeronautics and Space Administration Task Load Index mental demand (P < 0.05). Although group allocation did not influence the proportion of students who ultimately revived the patient (58% vs. 30%, P < 0.10), the HFenS students did so significantly more quickly (P < 0.01). The LFenS students had low immersion resulting in greater assessment anxiety. CONCLUSIONS: High-environmental fidelity simulation engendered immersion and a sense of urgency in students, whereas LFenS created assessment anxiety and slower performance. We conclude that once early-stage students have learned the basics of a clinical skill, throwing them in the "deep end" of high-fidelity simulation creates significant additional cognitive burden but this has considerable educational merit.

A structured framework improves clinical patient assessment and nontechnical skills of early career emergency nurses: a pre-post study using full immersion simulation

AIMS AND OBJECTIVES: The aim of this study was to evaluate the effect of the new evidence-informed nursing assessment framework HIRAID (History, Identify Red flags, Assessment, Interventions, Diagnostics, reassessment and communication) on the quality of patient assessment and fundamental nontechnical skills including communication, decision making, task management and situational awareness. BACKGROUND: Assessment is a core component of nursing practice and underpins clinical decisions and the safe delivery of patient care. Yet there is no universal or validated system used to teach emergency nurses how to comprehensively assess and care for patients. DESIGN: A pre-post design was used. METHODS: The performance of thirty eight emergency nurses from five Australian hospitals was evaluated before and after undertaking education in the application of the HIRAID assessment framework. Video recordings of participant performance in immersive simulations of common presentations to the emergency department were evaluated, as well as participant documentation during the simulations. Paired parametric and nonparametric tests were used to compare changes from pre to postintervention. RESULTS: From pre to postintervention, participant performance increases were observed in the percentage of patient history elements collected, critical indicators of urgency collected and reported to medical officers, and patient reassessments performed. Participants also demonstrated improvement in each of the four nontechnical skills categories: communication, decision making, task management and situational awareness. CONCLUSION: The HIRAID assessment framework improves clinical patient assessments performed by emergency nurses and has the potential to enhance patient care. RELEVANCE TO CLINICAL PRACTICE: HIRAID should be considered for integration into clinical practice to provide nurses with a systematic approach to patient assessment and potentially improve the delivery of safe patient care.

Comparison of different extrusion methods for compaction of powders

Densification of metallic powders by means of extrusion is regarded as a very attractive processing technique that allows obtaining a high level of relative density of the compact. However, the uniformity of the relative density depends on that of strain distribution and on the processing parameters. Several variants of extrusion can be used for compaction of metal particulates, including the conventional extrusion (CE) and equal channel angular pressing (ECAP), often referred to as equal-channel angular extrusion. Each of these processes has certain advantages and drawbacks with respect to compaction. A comparative study of these two extrusion processes influencing the relative density of compacts has been conducted by numerical simulation using commercial finite element software DEFORM2D. The results have been validated by experiments with titanium and magnesium powders and chips.

A damage accumulation model for complex strain paths: prediction of ductile failure in metals

The characterisation of strain path with respect to the directionality of defect formation is discussed. The criterion of non-monotonic strain path is used in the scalar and tensor models for damage accumulation and recovery. Comparable analysis of models and their verification has been obtained by simulation of crack initiation in a two-stage metal forming operation consisting of wire drawing followed by constrained upsetting.

Towards simulation of NASA35 axial compressor

Purpose – This paper aims to validate and analyse the NASA35 axial compressor performance based on a numerical approach. Design/methodology/approach – Knowledge about flow property change during compressor operation at high and relatively low speed is still limited. This work provides a numerical approach to address these problems. Validation of numerical methods is proposed to generate confidence the numerical approach adopted, and after that, analysis of compressor performance at different operation conditions is carried out. Findings – The numerical methods proposed are proved capable in predicting compressor performance. Changes of flow property during compressor operation are discussed and explained. Research limitations/implications – The current numerical work is carried out based on the first stage of the NASA35 axial compressor, where the interactive effects from adjacent stage are not counted in. Furthermore, the steady-state simulation enforces an averaging of flow at rotor-stator interface, where the transient rotor-stator interaction is removed. Practical implications – This work validates the numerical methods used in the prediction of NASA35 axial compressor performance, and a similar numerical approach can be used for other turbomachinery simulation cases. Originality/value – This work reinforces the understanding of axial compressor operation and provides reliable results for further investigation of a similar type of compressor. In addition, details of flow field within the NASA35 compressor during operation are given and explained which experiments still have difficult to achieve.

Cultural respect encompassing simulation training: being heard about health through broadband

BACKGROUND: Cultural Respect Encompassing Simulation Training (CREST) is a learning program that uses simulation to provide health professional students and practitioners with strategies to communicate sensitively with culturally and linguistically diverse (CALD) patients. It consists of training modules with a cultural competency evaluation framework and CALD simulated patients to interact with trainees in immersive simulation scenarios. The aim of this study was to test the feasibility of expanding the delivery of CREST to rural Australia using live video streaming; and to investigate the fidelity of cultural sensitivity - defined within the process of cultural competency which includes awareness, knowledge, skills, encounters and desire - of the streamed simulations. DESIGN AND METHODS: In this mixed-methods evaluative study, health professional trainees were recruited at three rural academic campuses and one rural hospital to pilot CREST sessions via live video streaming and simulation from the city campus in 2014. Cultural competency, teaching and learning evaluations were conducted. RESULTS: Forty-five participants rated 26 reliable items before and after each session and reported statistically significant improvement in 4 of 5 cultural competency domains, particularly in cultural skills (P<0.05). Qualitative data indicated an overall acknowledgement amongst participants of the importance of communication training and the quality of the simulation training provided remotely by CREST. CONCLUSIONS: Cultural sensitivity education using live video-streaming and simulation can contribute to health professionals' learning and is effective in improving cultural competency. CREST has the potential to be embedded within health professional curricula across Australian universities to address issues of health inequalities arising from a lack of cultural sensitivity training. Significance for public healthThere are significant health inequalities for migrant populations. They commonly have poorer access to health services and poorer health outcomes than the Australian-born population. The factors are multiple, complex and include language and cultural barriers. To address these disparities, culturally competent patient-centred care is increasingly recognised to be critical to improving care quality, patient satisfaction, patient compliance and patient outcomes. Yet there is a lack of quality in the teaching and learning of cultural competence in healthcare education curricula, particularly in rural settings where qualified trainers and resources can be limited. The Cultural Respect Encompassing Simulation Training (CREST) program offers opportunities to health professional students and practitioners to learn and develop communication skills with professionally trained culturally and linguistically diverse simulated patients who contribute their experiences and health perspectives. It has already been shown to contribute to health professionals' learning and is effective in improving cultural competency in urban settings. This study demonstrates that CREST when delivered via live video-streaming and simulation can achieve similar results in rural settings.

Simulation of progressive damage in composites using the enhanced embedded element technique

Analysis of complex composite structures requires a fine contiguous mesh of threedimensional (3D) solid elements. The embedded element technique is a promising technique for predicting stiffness and stress. This paper presents a new method for enhancing the embedded element with continuum damage mechanics methods for predicting the evolution of damage in fiber reinforced composite structures. Comparison of the model prediction with experimental results reveals an excellent correlation between the tensile strength of quasi-isotropic laminate with an open hole. The embedded element technique allows the fiber reinforcement and matrix domains to be meshed independently and failure is evaluated separately in each domain. The enhanced embedded element approach allows the failure modes to be observed, specifically, the evolution of matrix cracking and fiber rupture. Compared to the traditional contiguous mesh finite element method, the present modelling technique demonstrates a clear advantage in predicting the experimentally observed failure modes and accurate characterisation of intralaminar fracture.