Low birth weight as an additional indication for chromosomal analysis

INTRODUCTION: Even though there are few epidemiological studies evaluating the birth weights of different groups of malformed babies with chromosomal abnormalities, it is widely known that infants with trisomy 18, and to a lesser degree those with trisomy 13 and other chromosomal alterations, have low birth weights. PATIENTS AND METHODS: In this study we present the analysis of the birth weights and gestational ages of a large sample of babies (23,155 malformed and a similar number of nonmalformed babies), separating the different groups of chromosomal anomalies and comparing the weight in the clinical groups of malformed infants. RESULTS: Most of the groups with chromosomal abnormalities present lower birth weights in comparison to the other groups. CONCLUSIONS: The results of our study support the conclusion that the relationship between chromosomal alterations and low birth weight is sufficiently important that such a low birth weight in children with minor or major anomalies should be considered as one more indication to perform chromosomal analysis.     

Analysis of the /spl Sigma/-/spl Delta/ pulsed digital oscillator for MEMS

The aim of this paper is the analysis, simulation, and experimental verification of the /spl Sigma/-/spl Delta/ pulsed digital oscillator (PDO) topology. As it has been shown in previous works, the oscillation frequency and output spectrum in the PDO depend on the sampling frequency, the natural frequency of the microelectromechanical systems (MEMS) resonator and its damping factor. Here, extensive discrete-time simulations have been carried out which show that the normalized oscillation frequency as a function of the normalized natural frequency of the resonator is very similar to a distorted Devil's Staircase fractal. This nonlinear behavior is a direct consequence of the damping losses of the MEMS resonator. Analytical conditions for a perfect oscillation at the natural frequency of the resonator are also calculated. For this set of what we call "perfect" frequencies, it is also shown that the energy transfer from the electrical to the mechanical domain is maximum. Then a more generalized structure of the oscillator is considered and the drawn conclusions are tested against experimental results obtained from an oscillator prototype which uses a MEMS resonator with thermoelectric actuation and piezoresistive position sensing.     

Electrochemical behaviour of indium ions in molten equimolar CaCl2–NaCl mixture at 550 ∘C

The stability of indium chloride and oxide as well as the electrochemical behaviour of indium ions have been studied in the equimolar CaCl2–NaCl melt at 550 C by X-ray diffraction (XRD) and different electrochemical techniques, using molybdenum and tungsten wires as working electrodes. Voltammetric and chronopotentiometric studies showed signals attributed to the presence of three oxidation states of indium, i.e. 0, i and iii. The standard potential of the redox couples, as well as the solubility products of indium oxides have been determined, showing that In(iii) ions are completely reduced to monovalent indium by the indium metal according to the reaction: In () + 2 In 3 In () and that In₂O is a strong oxide donor according to the reaction: In₂O(s) 2 In() + O^2- These results have allowed the construction of E-pO2– equilibrium diagrams summarising the properties of In–O compounds. The electrodeposition of indium was uncomplicated at Mo and W electrodes. Very good adherence of liquid indium to the electrode materials was observed, with the formation of Na–In alloys at highly reducing potentials, and there was no evidence of indium dissolution into the melt. Moreover, the voltammograms corresponding to the electrochemical In(iii)/In(i) exchange were well defined. The two electrochemical steps were found to be quasi-reversible, and the values of the kinetic parameters, ko and , for both reactions, as well as the diffusion coefficients, DIn(III) and DIn(I) were calculated.     

Effects of acid leaching treatment of soda-lime silicate glass on crack initiation and fracture

Water or acid soaking surface treatments have been shown to increase the mechanical strength of soda-lime silicate (SLS) glasses. This increase in strength has traditionally been attributed to effects related to residual stress or changes in fracture resistance. In this work, we report experimental data that cannot be explained based on the existing knowledge of glass surface mechanics. In dry environments, annealed and acid-leached SLS surfaces have comparable crack initiation stress and fracture stress as measured by Hertzian indentation and biaxial bending tests, respectively. Yet, in the presence of humidity, acid-leached surfaces have higher failure stress than the annealed surfaces. This apparent enhancement in the crack resistance of the acid-leached surface of SLS glass in humid environments supports the hypothesis that acid-leached surface chemistry can lower the transport kinetics of molecular water to critical flaws.     

Error Analysis for hp-FEM Semi-Lagrangian Second Order BDF Method for Convection-Dominated Diffusion Problems

We present in this paper an analysis of a semi-Lagrangian second order Backward Difference Formula combined with hp-finite element method to calculate the numerical solution of convection diffusion equations in ℝ². Using mesh dependent norms, we prove that the a priori error estimate has two components: one corresponds to the approximation of the exact solution along the characteristic curves, which is O(Dt²+h^m+1(1+\frac\mathopen|logh|Dt))O(\Delta t^{2}+h^{m+1}(1+\frac{\mathopen{|}\log h|}{\Delta t})); and the second, which is O(Dt^p+|| [(u)\vec]-[(u)\vec]_h||_L^￥)O(\Delta t^{p}+\| \vec{u}-\vec{u}_{h}\|_{L^{\infty}}), represents the error committed in the calculation of the characteristic curves. Here, m is the degree of the polynomials in the finite element space, [(u)\vec]\vec{u} is the velocity vector, [(u)\vec]_h\vec{u}_{h} is the finite element approximation of [(u)\vec]\vec{u} and p denotes the order of the method employed to calculate the characteristics curves. Numerical examples support the validity of our estimates.     

Influence of deposited metal structures on the failure mechanisms of silicon-based components

Miniaturised silicon-based multilayer chips are nowadays widespread as semiconductor components for the mobile device technology. The use of special processing and integration procedures requires such materials to possess a definite mechanical strength to ensure the functionality of the entire device. The strength and mechanical reliability of such components can be described by the Weibull theory, and is highly influenced by the geometry of the metallisation and other near-surface functional layers. In this work, we attempt to clarify the mechanisms leading to the failure of the metallised side of Si-chip components. The combined use of Finite Elements (FE) and Focused Ion Beam (FIB) analyses allowed recognising that cracks are induced in the metal-oxide-silicon interfacial area well before complete failure of the component. Such cracks have a crucial role in the lower strength and higher Weibull modulus observed on the metallised side.     

A general method for evaluating the overhead when consolidating servers: performance degradation in virtual machines and containers

The Journal of Supercomputing - Server consolidation is one of the most commonly used techniques for reducing energy consumption in datacenters; however, this results in inherent performance...