Waveform Approach for Assessing Conformity of CISPR 16-1-1 Measuring Receivers

An alternative approach for assessing the conformity of electromagnetic interference measuring receivers with respect to the baseline CISPR 16-1-1 requirements is proposed. The method’s core is based on the generation of digitally synthesized complex waveforms comprising multisine excitation signals and modulated pulses. The superposition of multiple narrowband reference signals populating the standard frequency bands allows for a single-stage evaluation of the receiver’s voltage accuracy and frequency selectivity. Moreover, characterizing the response of the weighting detectors using modulated pulses is more repeatable and less restrictive than the conventional approach. This methodology significantly reduces the amount of time required to complete the verification of the receiver’s baseline magnitudes, because time-domain measurements enable a broadband assessment while the typical calibration methodology follows the time-consuming narrow band frequency sweep scheme. Since the reference signals are generated using arbitrary waveform generators, they can be easily reproduced from a standard numerical vector. For different test receivers, the results of such assessment are presented in the 9 kHz–1 GHz frequency range. Finally, a discussion on the measurement uncertainty of this methodology for assessing measuring receivers is given.Postprint (author's final draft

Improvement in Low Frequency Emission Test Method by Live Impedance Measurement

The MIL-STD-461 CE101 test is one of the essential low-frequency emission tests in the range of 30 Hz – 10 kHz for military and aerospace equipment, however, its application remains challenging. The primary concern is the effect of the power source or grid impedance on test results because the LISNs are not functional in such a low-frequency range. Therefore, the emission levels depend on the source impedance and, consequently, the reproducibility of test results is generally poor. In this paper, we thoroughly analyze this problem and propose a solution based on the live impedance measurement of the CE101 test circuit. For the live impedance measurement, we used the CS101 military low-frequency immunity test system along with the addition of FFT and current measurement capabilities

Opportunities for organoids as new models of aging.

The biology of aging is challenging to study, particularly in humans. As a result, model organisms are used to approximate the physiological context of aging in humans. However, the best model organisms remain expensive and time-consuming to use. More importantly, they may not reflect directly on the process of aging in people. Human cell culture provides an alternative, but many functional signs of aging occur at the level of tissues rather than cells and are therefore not readily apparent in traditional cell culture models. Organoids have the potential to effectively balance between the strengths and weaknesses of traditional models of aging. They have sufficient complexity to capture relevant signs of aging at the molecular, cellular, and tissue levels, while presenting an experimentally tractable alternative to animal studies. Organoid systems have been developed to model many human tissues and diseases. Here we provide a perspective on the potential for organoids to serve as models for aging and describe how current organoid techniques could be applied to aging research

Carta al Editor

La Línea de Educación Infantil, organismo académico, adscrito al Doctorado en Educación y al Centro de Investigación Educativa del Instituto Pedagógico de Caracas-UPEL, le agradece al Consejo Editorial de la Revista de Investigación, coordinada por la profesora Dalia Diez de Tancredi, la gentil invitación que implica la publicación de un número especial, producido por nuestra línea de investigación y dedicado a la Educación Infantil en Venezuela.Uno de los objetivos centrales de esta línea, consiste en promover la divulgación de los trabajos de investigación de sus miembros. Es por eso que la participación de un grupo de profesionales investigadores, dedicados al estudio de diferentes temas sobre la Educación Infantil, permite la presentación de una serie de artículos que ofrecen variadas posiciones en relación a los tópicos propuestos y en cierta forma vienen a enriquecer las investigaciones en esta área.Desde la perspectiva organizacional, la línea plantea la realizaciónde actividades en el ámbito de la docencia, la extensión y la investigación. Se orienta mediante una administración horizontal, donde todos sus miembros ocupan un nivel jerárquico equivalente y ejecutan roles que bien pueden alternarse de acuerdo a las responsabilidades administrativas de la línea.En esta oportunidad, el Consejo Editorial de la Revista de Investigación del IPC-UPEL, ofrece una alternativa que representa un demostrativo ejemplo de como se debe gerenciar la promoción de la investigación

The role of the Guayana Development Corporation in Venezuelan industrialization : diversification or vertical integration

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1987.Bibliography: leaves 81-83.by Antonio J. Azpurua C.M.C.P

The Insulin-Like Growth Factor System in the Long-Lived Naked Mole-Rat.

Naked mole-rats (Heterocephalus glaber) (NMRs) are the longest living rodents known. They show negligible senescence, and are resistant to cancers and certain damaging effects associated with aging. The insulin-like growth factors (IGFs) have pluripotent actions, influencing growth processes in virtually every system of the body. They are established contributors to the aging process, confirmed by the demonstration that decreased IGF signaling results in life-extending effects in a variety of species. The IGFs are likewise involved in progression of cancers by mediating survival signals in malignant cells. This report presents a full characterization of the IGF system in the NMR: ligands, receptors, IGF binding proteins (IGFBPs), and IGFBP proteases. A particular emphasis was placed on the IGFBP protease, pregnancy-associated plasma protein-A (PAPP-A), shown to be an important lifespan modulator in mice. Comparisons of IGF-related genes in the NMR with human and murine sequences indicated no major differences in essential parts of the IGF system, including PAPP-A. The protease was shown to possess an intact active site despite the report of a contradictory genome sequence. Furthermore, PAPP-A was expressed and translated in NMRs cells and retained IGF-dependent proteolytic activity towards IGFBP-4 and IGF-independent activity towards IGFBP-5. However, experimental data suggest differential regulatory mechanisms for PAPP-A expression in NMRs than those described in humans and mice. This overall description of the IGF system in the NMR represents an initial step towards elucidating the complex molecular mechanisms underlying longevity, and how these animals have evolved to ensure a delayed and healthy aging process

A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites

Variographic analysis of public exposure to electromagnetic radiation due to cellular base stations

The spatial structure of the vertical component of the electric field emitted by base stations in the Brussels region (Belgium) is measured, and studied using the variogram. A relationship between the variogram shape and base station antenna density in each measurement area is found; the variogram range and sill level are shown to depend on cellular base stations’ antenna density, following exponential laws. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc.FLWINinfo:eu-repo/semantics/publishe

Transcatheter aortic valve implantation despite challenging vascular access.

We describe transcatheter aortic valve implantation in a patient who had severe peripheral artery disease. The patient\u27s vascular condition required additional preliminary peripheral intervention to enable adequate vascular access. A 78-year-old man with severe aortic stenosis, substantial comorbidities, and severe heart failure symptoms was referred for aortic valve replacement. The patient\u27s 20-mm aortic annulus necessitated the use of a 23-mm Edwards Sapien valve inserted through a 22F sheath, which itself needed a vessel diameter of at least 7 mm for percutaneous delivery. The left common femoral artery was selected for valve delivery. The left iliac artery and infrarenal aorta underwent extensive intervention to achieve an intraluminal diameter larger than 7 mm. After aortic valvuloplasty, valve deployment was successful, and the transaortic gradient decreased from 40 mmHg to less than 5 mmHg. The patient was discharged from the hospital 4 days postoperatively. We conclude that transcatheter aortic valve implantation can be successfully performed in patients with obstructed vascular access, including stenosis of the infrarenal aorta and the subclavian and coronary arteries