Blood lead concentrations and iron deficiency in Canadian aboriginal infants

Aboriginal Cree infants living in northern Quebec who were 9 months of age were screened for anemia, iron deficiency and elevated blood lead concentrations. Of the 314 infants who were eligible to participate, 274 (87.3%) were screened for anemia, 186 had blood lead concentration measured and 141 of the latter group had iron status determined. The median blood lead concentration was 0.08 micromol/l (range 0.01-1.00 micromol/l). The 25, 50 and 75 percentiles for blood lead concentration were 0.05, 0.08 and 0.12 micromol/l, respectively. The prevalence of elevated blood lead concentrations (> 0.48 micromol/l) was 2.7% (95% Cl 0.36-5.0). Among infants who had blood lead measured, the prevalence of anemia (hemoglobin < 110 g/l) was 25.0% and 7.9% of infants had iron-deficiency anemia (hemoglobin < 110 g/l and serum ferritin < 10 microg/l). Anemic infants had a higher mean geometric blood lead concentration than did babies without anemia (0.11 micromol/l vs. 0.07 micromol/l, P = 0.003). Likewise, infants with iron-deficiency anemia had a significantly higher mean geometric blood lead concentration than infants without iron deficiency anemia (0.16 micromol/l vs. 0.07 micromol/l, P = 0.001). There was a significant negative correlation between blood lead and hemoglobin concentrations (r = -0.203, P = 0.006) and between blood lead and serum ferritin concentrations (r = -0.245, P = 0.003). Infants who were fed traditional food (fish, fowl and game) did not have a significantly different mean geometric blood lead concentration, hemoglobin concentration or serum ferritin concentration than infants who did not eat traditional food. Few infants (5.3%) ate traditional food daily.     

Stability of small group interaction and achievement over time.

Investigated the stability over time of student behavior in small groups and the relationships among student and group characteristics, group interaction, and achievement. 110 students in 3 average-ability 7th- and 8th-grade mathematics classrooms worked for one semester in small groups. Group interaction and achievement were measured in 2 3-wk instructional units, 3 mo apart on perimeter, area, and volume and on the metric system. For both occasions, giving explanations was positively related to achievement and receiving no explanation in response to a question or error (receiving no response or a terminal response) was negatively related to achievement. The input–process–achievement relations were also fairly stable over time: For both occasions, group interaction partially mediated the effects of relative ability within the group and intellectual achievement responsibility on achievement. There were significant differences among group compositions (uniform-ability groups and 2 kinds of mixed-ability groups) in interaction and achievement at the 1st instructional unit but not at the 2nd one. In contrast to the stability of relationships among variables over time, student and group behavior tended to be unstable over time. Possible explanations for the instability of student and group behavior are discussed, as well as the implications of this result for instruction and further research. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implementation of mixed time integration techniques on a vectorized computer with shared memory

The implementation of subcycling in an explicit finite element program executed on a concurrent computer with shared memory is described. The effects of vectorization and parallelization on the speed-up and efficiency achieved with subcycling is discussed. Numerical studies are presented to illustrate the effects of the number of processors, the size of element blocks and problem size. Finally, an efficient allocation algorithm which minimizes the effects of processor idleness is presented.     

Online complete coverage path planning using two-way proximity search

This paper presents an efficient online approach for complete coverage path planning of mobile robots in an unknown workspace based on online boustrophedon motion and an optimized backtracking mechanism. The presented approach first performs a single continuous boustrophedon motion until a critical point is reached. In order to completely cover the environment, next starting point is decided by using the accumulated knowledge of the environment map. An efficient backtracking technique based on proposed Two-way Proximity Search algorithm is used to plan a path from the critical point to the new starting point. Simulation results show the efficiency of proposed backtracking approach with improved total coverage time, coverage path length and memory requirements.     

Advanced DAG-Based Ranking (ADR) Protocol for Blockchain Scalability

In the past decade, blockchain has evolved as a promising solution to develop secure distributed ledgers and has gained massive attention. However, current blockchain systems face the problems of limited throughput, poor scalability, and high latency. Due to the failure of consensus algorithms in managing nodes’identities, blockchain technology is considered inappropriate for many applications, e.g., in IoT environments, because of poor scalability. This paper proposes a blockchain consensus mechanism called the Advanced DAG-based Ranking (ADR) protocol to improve blockchain scalability and throughput. The ADR protocol uses the directed acyclic graph ledger, where nodes are placed according to their ranking positions in the graph. It allows honest nodes to use the Direct Acyclic Graph (DAG) topology to write blocks and verify transactions instead of a chain of blocks. By using a three-step strategy, this protocol ensures that the system is secured against doublespending attacks and allows for higher throughput and scalability. The first step involves the safe entry of nodes into the system by verifying their private and public keys. The next step involves developing an advanced DAG ledger so nodes can start block production and verify transactions. In the third step, a ranking algorithm is developed to separate the nodes created by attackers. After eliminating attacker nodes, the nodes are ranked according to their performance in the system, and true nodes are arranged in blocks in topological order. As a result, the ADR protocol is suitable for applications in the Internet of Things (IoT). We evaluated ADR on EC2 clusters with more than 100 nodes and achieved better transaction throughput and liveness of the network while adding malicious nodes. Based on the simulation results, this research determined that the transaction’s performance was significantly improved over blockchains like Internet of Things Applications (IOTA) and ByteBall.     

MHD 3D free convective flow of nanofluid over an exponentially stretching sheet with chemical reaction

This paper deals with a problem where the effect of variable magnetic field and chemical reaction on free convective flow of an electrically conducting incompressible water based nanofluid over an exponentially stretching sheet has been investigated. In the present study, Buongiorno model associated with Brownian motion and thermophoretic diffusion is employed to describe the heat transfer enhancement of nanofluids. Some suitable similarity transformations reduced the governing boundary layer non-linear partial differential equations into a set of ordinary non-linear differential equations. The transformed equations are then solved numerically using fourth order Runga-Kutta method along with Shooting technique. The major outcomes of the present study is that the magnetic field impedes the fluid motion while thermal as well as mass buoyancy forces accelerate it, the thermophoretic diffusion enhances dimensionless fluid temperature as well as concentration leading to thicker thermal and concentration boundary layers. On the other hand, concentration exponent, Brownian motion parameter and chemical reaction parameter exhibit reverse trend on temperature and concentration. In addition, the presence of magnetic field under the influence of thermal as well as mass buoyancies supports to reduce the rate of heat transfer as well as wall shear stress while the first order chemical reaction develops a thinner concentration boundary layer.     

Experimental and theoretical studies on the corrosion inhibition of vitamins – Thiamine hydrochloride or biotin in corrosion of mild steel in aqueous chloride environment

The corrosion inhibition of thiamine hydrochloride (vitamin B1) or biotin (vitamin B7) on corrosion of mild steel in 240 ppm chloride ions solution was studied using weight loss method, potentiodynamic polarization curves and electrochemical impedance spectroscopy. UV–Vis, FTIR and surface analysis using SEM and EDS characterization were carried out to understand the corrosion inhibition property of these inhibitors in 240 ppm aqueous chloride medium. Experimental results show that both thiamine hydrochloride and biotin act as a good corrosion inhibitors. Quantum chemical parameters obtained from density functional theory (DFT) calculations were discussed with experimental results.     

Influence of heat transfer on a peristaltic flow of Johnson Segalman fluid in a non uniform tube

The present investigation deals with the peristaltic motion of an incompressible non-Newtonian fluid in a non-uniform tube for long wavelength. The mechanical properties of the material are represented by the constitutive equation for a Johnson Segalman fluid. The resulting problem for velocity field and temperature profile is solved using (i) Regular perturbation method (ii) Homotopy analysis method. The influence of various emerging parameters on the flow is shown through graphs and discussed.