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The apprehension of the last three factors of the Drake equation, fi · fc · L, is misguided or at least not very well examined. This article scrutinizes the underlying suppositions involved in the search for extraterrestrial intelligence (SETI) research. What is meant by “intelligence,” “technology,” and “civilization”? What makes them possible, and how do they evolve? The present examination aims

In this work, we propose a method for determining an optimal, non-uniform, sampling scheme for multi-dimensional signals by solving a convex optimization problem reminiscent of the sensor selection problem. The optimal sampling scheme is determined given a suitable estimation bound on the parameters of interest, as well as incorporating any imprecise a priori knowledge of the locations of the para

This work proposes a frequency and amplitude estimator tailored for noise corrupted signals that have been clipped. Formulated as a sparse reconstruction problem, the proposed algorithm estimates the signal parameters by solving an atomic norm minimization problem. The estimator also exploits the waveform information provided by the clipped samples, incorporated in the form of linear constraints t

In this work, we propose a method for determining a non-uniform sampling scheme for multi-dimensional signals by solving a convex optimization problem reminiscent of the sensor selection problem. The resulting sampling scheme minimizes the sum of the Cramér–Rao lower bounds for the parameters of interest, given a desired number of sampling points. The proposed framework allows for selecting an arb

We consider channel estimation (CE) in narrowband Internet-of-Things (NB-IoT) systems. Due to the fluctuations in phase within receiver and transmitter oscillators, and also the residual frequency offset (FO) caused by discontinuous receiving of repetition coded transmit data-blocks, random phase noises are presented in received signals. Although the coherent-time of fading channel can be assumed

Channel measurements of large-scale multiuser multiple-input multiple-output (MU-MIMO) radio propagation channels are presented. In the setup, three users with patch antennas communicate simultaneously with a base station (BS) equipped with a large antenna array in an indoor environment. Both a uniform linear array (ULA) and a uniform planar array (UPA) are used, and their relative ability to sepa

The effects of five different calcium antagonists (diltiazem, felodipine, nifedipine, nimodipine, and verapamil) on cat skeletal muscle resistance and capacitance vessels were studied in a whole organ preparation. These calcium antagonists seemed to have the similar qualitative effects on these vascular functions. Calcium antagonists were found to be potent inhibitors of myogenic vascular reactivi

As the demand for connectivity and infotainment services increases in the automotive world, the need to measure and characterize the propagation channels inside vehicles also increases. In this work, a measurement study was performed to investigate the influence of RF cables on in-vehicle channels. It was found that, for the same transmit and receive antenna positions, the routing of the measureme

Barbiturates are used clinically as anaesthetics and to reduce raised intracranial pressure. One side effect is hypotension, usually ascribed to a depression of cardiac contractility, while their effects on the resistance vessels are more controversial: both vasodilation and vasoconstriction have been described. This study analyzes the effects of thiopental on basal vascular tone in the cat skelet

The introduction of picture and archiving communicating systems is currently being evaluated in several institutions. We decided, as an intermediate step, to see if image quality after transferral to a personal computer (PC) is sufficient for the diagnostic needs in an intensive care unit. Seventy-five portable digital chest radiographs were studied both as hard-copies and on a monitor after trans

The international standard ISO 22400 has defined a set of Key Performance Indicators (KPIs) to evaluate the performance of manufacturing operation. However, the defined KPIs seem to be inspired from the discrete production context, and hence do not automatically fit the process industry context. The process industry is defined as the industry in which the raw material undergoes conversion during a

BACKGROUND: Inhaled nitric oxide may be useful in the treatment of pulmonary hypertension and hypoxaemia. Nitric oxide is rapidly oxidized to nitrogen dioxide, which is toxic and may adversely affect the airways of the patient. The aim of the present investigation was to examine factors that may affect the concentration of nitrogen dioxide, using the Servo Ventilator 300 nitric oxide delivery syst

We have evaluated the kinetics of nitrogen dioxide production in a system for inhalation of nitric oxide. In addition to a small fraction of contamination of nitrogen dioxide in the nitric oxide stock gas, a considerable part of the total concentration of nitrogen dioxide is formed immediately after mixing of nitric oxide and oxygen. This initial build-up of nitrogen dioxide is followed by a linea

We have analysed the ability of three nitrogen dioxide absorbing materials (soda lime, noXon and zeolite) to act as nitrogen dioxide scavengers during delivery of inhaled nitric oxide. Different mixtures of gas were produced in a ventilator (Servo Ventilator 300) and passed through an inspiratory tube. Concentrations of nitrogen dioxide and nitric oxide were measured in the distal part of the tube

BACKGROUND: The release of neuron-specific astroglial S-100 protein to the cerebrospinal fluid is a marker of cerebral damage. The aim of this study was to determine the pattern of release of S-100 protein to serum after pediatric cardiac operations and extracorporeal circulation.METHODS: Sequential blood samples from 97 children (up to 16 years) were taken after induction of anesthesia, immediate