17 research outputs found

    PGO models in the envelope function and effective mass approximations

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    A recipe to design quantum devices that exhibit the theoretical pseudo-Gaussian oscillator electronic states properties is given. The algorithm is described en detail and is illustrated by the computation of a Mn x Cd 1- x Te ternary alloy pseudo-Gaussian heterostructure. The numerical procedure reaches beyond of pseudo-Gaussian models and can be used for designing epitaxial growth devices with desired electronic states structure. The calculations are carried out in the envelope function and effective mass approximations. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2011

    Challenges in sonographic detection of fetal major structural abnormalities at the first trimester anomaly scan

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    First-trimester (FT) ultrasound examination appears to have a very good sensitivity in the detection of fetal abnormalities, especially when an extended protocol that is achievable with reasonable resources of time, personnel and ultrasound equipment, is used. It has been shown that the efficiency of the routine anomaly scan varies widely between the studies performed both in early or mid-pregnancy. The analysis of technique and study designs reveals that in each gestational age, the extension of the investigational protocol is the most important factor in modulating the detection rate. Moreover, the use of similar basic checklists at the FT and second trimester (ST) examinations revealed comparable anomaly detection rates in large population groups. First trimester combined test have been demonstrated as a useful screening tool for genetic syndromes and consecutively the FT ultrasound scan became a routine examination in most prenatal diagnostic centers. Its performance in structural abnormalities detection has been communicated in high-, medium-risk populations or unselected low-risk variable number of patients and compared to the ST anomaly scan effectiveness. A detailed first-trimester anomaly scan using an extended protocol is an efficient screening method to detect major fetal structural abnormalities in lowrisk pregnancies. It is a method that it is feasible at 12 to 13 + 6 weeks with ultrasound equipment and personnel already used for routine first-trimester screening. Rate of detection of severe malformations is greater in early- than in mid-pregnancy and on postnatal evaluation. Early heart investigation could be improved by an extended protocol involving use of color Doppler. © 2015, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved

    Applications of ultrasound in prelabor and labor

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    Ultrasound is a crucial part of everyday obstetrical practice and becomes more and more important in the management of traditionally clinical aspects of obstetrics, such as management of labor and delivery, offering a possibly more objective method of examination. The rate of labor induction has doubled in the last two decades and more objective methods are needed to assess the possible outcome of an induction and help clinicians in order to counsel women appropriately. Regarding the management of labor there is extensive evidence that clinical assessment during labor is not accurate, with potential consecutive major implications in the decision-making and the prognosis of the delivery mode. Several studies have shown that ultrasound is an objective method of assessing labor and its progress and is very helpful in decision-making for instrumental deliveries. The purpose of this article is to review the evidence available in literature regarding the benefits and the role in general of ultrasonography in prelabor and labor

    Soft computing in absorption cooling systems

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    Absorption cooling systems make sense in many applications for process water cooling. Instead of mechanically compressing a refrigerant gas, as in the conventional vapor compression process, absorption cooling uses a thermo-chemical process. Two different fluids are used, a refrigerant and an absorbent. Heat directly from natural gas combustion, solar energy, waste-heat source or indirectly from a boiler, drives the process. In recent years, soft computing (SC) methods have been widely utilized in the analysis of absorption cooling systems. Soft computing is becoming useful as an alternate approach to conventional techniques. Soft computing differs from conventional (hard) computing in that, unlike hard computing, it is tolerant of imprecision, uncertainty, partial truth, and approximation. In this chapter, the research of applying soft computing methods for absorption cooling applications is presente
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