Frequency

The paper examines electrophysiological activity produced by exposing the brains of laboratory animals to rectangular pulses of microwave energy. These results suggest that a microwave auditory phenomenon is evoked by a mechanism similar to conventional sound reception, and that the primary interaction site is peripheral to the cochlea. It is shown that the peak pressure due to thermal expansion is greater than the radiation pressure or electrostriction, and that the induced sound frequency is only a function of the size and acoustic property of the brain. Several suggestions were made for future research in microwave auditory effect and its health implications. ~~~~~~~ TITLE: Sensation and perception of microwave energy Authors: Michaelson, S. M. (Rochester Univ.)

Research shows that cellular and mitochondrial (ΔΨm) membrane potentials are strong indicators of cellular physiology. In this paper we review further research suggesting that microcurrent frequencies can positively influence both these membrane potentials. The goal of this research is to show how microcurrent might stimulate physiological potentials in order to support a healthy function of bioelectric fields of cells and organs. In the second part of the article, a study to examine the effects of microcurrent application on the body's response to electric measurements is presented, in particular to a change in voltage-current lag known as a phase angle. The test involved measuring bioimpedance of a person before and after a 30-minute application with microcurrent stimulation. Fifteen healthy subjects were examined through impedance measurements taken on one arm. The results showed a consistent increase in phase angle directly after the stimulation, confirming a widely accepted indication of health improvement on a cellular level. These results are encouraging and justify further investigations on the effect of microcurrent stimulation on the human body in relation to general cellular health and regenerative functions.

Abstmct-Experimental and theoretical studies have revealed several effects in surface-acoustic-wave chirp filters that arise from electrode reflections. One effect is that down-chirp filters have lower loss than up-chirp filters, which is shown to be caused by ...

ÐEfficient and effective buffering of disk blocks in main memory is critical for better file system performance due to a wide speed gap between main memory and hard disks. In such a buffering system, one of the most important design decisions is the block replacement policy that determines which disk block to replace when the buffer is full. In this paper, we show that there exists a spectrum of block replacement policies that subsumes the two seemingly unrelated and independent Least Recently Used (LRU) and Least Frequently Used (LFU) policies. The spectrum is called the LRFU (Least Recently/Frequently Used) policy and is formed by how much more weight we give to the recent history than to the older history. We also show that there is a spectrum of implementations of the LRFU that again subsumes the LRU and LFU implementations. This spectrum is again dictated by how much weight is given to recent and older histories and the time complexity of the implementations lies between O(1) (the time complexity of LRU) and ylog P n (the time complexity of LFU), where n is the number of blocks in the buffer. Experimental results from trace-driven simulations show that the performance of the LRFU is at least competitive with that of previously known policies for the workloads we considered.

The aim of the present study was to investigate the prevalence of left ventricular (LV) thrombus formation and important determinants in patients with acute ST elevation myocardial infarction localized to the anterior wall treated with percutaneous coronary intervention (PCI) and dual-antiplatelet therapy. One hundred selected patients with ST elevation myocardial infarctions revascularized with PCI in the left anterior descending coronary artery were included. The patients participated in the Autologous Stem Cell Transplantation in Acute Myocardial Infarction (ASTAMI) trial. All were treated with aspirin 75 mg/day and clopidogrel 75 mg/day and underwent serial echocardiography and magnetic resonance imaging during the first 3 months after PCI. After 4 to 5 days, the ejection fraction and infarct size in percentage of the left anterior descending coronary artery area were assessed using single photon-emission computed tomography in addition to the ejection fraction by echocardiography. LV thrombi were detected in 15 patients during the first 3 months, 2/3 of them within the first week. No differences in baseline characteristics between the groups with and without LV thrombi were shown. However, in the thrombus group, significantly higher peak creatine kinase levels (6,128 vs 2,197 U/L, p <0.01), larger infarct sizes (82.5% vs 63.8%, p <0.01), and lower ejection fractions on single photon-emission computed tomography (35.5% vs 40.0%, p ‫؍‬ 0.03) and on echocardiography (43.0% vs 46.0%, p ‫؍‬ 0.03) were found compared to patients without LV thrombi. In conclusion, LV thrombus formation is a frequent finding in patients with anterior wall ST elevation myocardial infarction treated acutely with PCI and dualantiplatelet therapy and should be assessed by echocardiography within the first week.

Volcanoes generate a variety of pre-eruptive lowfrequency seismic signals. Hybrid earthquakes comprise a class of these signals having high-frequency onsets followed by low-frequency ringing. They are used empirically to predict eruptions, but their ambiguous physical origin limits their diagnostic use. The short-duration, near-field hybrid seismograms associated with the 2004 Mount St. Helens eruption indicate that much of the prolonged signal is due to path rather than resonating fluids. We show using seismic source spectra that the hybrids have a corner frequency/ seismic moment relationship that scales consistently with brittle-failure. The unusually low frequency of these earthquakes can result from low rupture velocities combined with strong path effects due to their shallow sources. This new application of near-field instrumentation provides the first seismological evidence for brittle-failure as a major process in dome building, and suggests that hybrids should not be used as direct indicators of fluids.

Details are given on a method of tuning a hydrogen maser cavity by means of a variable capacitance diode placed in a loop directly inside the cavity. The design of the loop-in which the varactor is placed, the loop connection to an external dc bias, and a theoretical analysis of the whole loop system (cavity, tuning loop, and coupling loop) are also given.

The digital waveguide mesh is an extension of the onedimensional (1-D) digital waveguide technique. The mesh can be used for simulation of two-and three-dimensional (3-D) wave propagation in musical instruments and acoustic spaces. The original rectangular digital waveguide mesh algorithm suffers from direction-dependent dispersion. Alternative geometries, such as the triangular mesh, have been proposed previously to improve the performance of the mesh. In this paper, we show that the dispersion problem may be reduced using various other techniques. These methods include multidimensional interpolation, optimization of the point-spreading function, and frequency warping. We compare the accuracy and computational complexity of these techniques in the two-dimensional (2-D) case and conduct numerical simulations of a membrane. A rectangular mesh using second-order Lagrange interpolation can be implemented without multiplications, but its accuracy is worse than that of other enhanced structures. The most accurate technique in terms of the relative frequency error is the warped triangular mesh whose maximum error is 0.6%. The warped rectangular mesh with optimized weighting coefficients is not as exact, but still offers a 1.2% accuracy.

Purpose: In adrenocortical tumors (ACT), Wnt/β-catenin pathway activation can be explained by β-catenin somatic mutations only in a subset of tumors. ACT is observed in patients with familial adenomatous polyposis (FAP) with germline APC mutations, as well as in patients with Beckwith-Wiedemann syndrome with Wilms' tumors reported to have WTX somatic mutations. Both APC and WTX are involved in Wnt/β-catenin pathway regulation and may play a role in ACT tumorigenesis. The aim of this study was to report if APC and WTX may be associated with FAP-associated and sporadic ACT.

Abstract— This paper presents an adaptive control scheme for suppressing jitter in laser beams. The variable-order adaptive controller is based on an adaptive lattice filter that implicitly identifies the disturbance statistics from real-time sensor data. The multi-channel adaptive ...

A typical 1 /f noise is excited in a GaAs filament with the Hooge's noise parameter of about aH = 2 x The noise level increases in proportion to the square of the terminal voltage, and decreases approximately in inverse proportion to the total number of carriers within the device. A transition from the typical 1 lfnoise characteristics to the diffusion noise characteristics of MESFET's was observed when the electric field was increased above 1 kV/cm. The noise parameters were also investigated as a function of the device width between 2 and 200 pm. Deep levels within the n-GaAs active layer and the high electric field are the main factors of the nonideal l/fcharacteristics.

Noninverting operational amplifiers cannot readily be used for various Sallen and Key filters because they cannot provide gain less than unity. A simple network modification is suggested that overcomes this limitation and introduces an added degree of freedom with parameters that are determined by passive components only.

Absiruct4alculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would he the case for printed antennas at millimeter wave frequeneies. Prioted dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, abd gallium arsenide substrate are considered. Data are given for resonant length, resoriant resistance, bahdwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. A h presented is an optimizatidn procedure for maximizing or minimizing power launched into surface waves from a multielemerit printed antenna array. The data are calculated by a moment method solution.

Since minimizing the co-channel interference in the conventional cellular technologies (AMPS, TDMA, and GSM) leads to better spectral efficiency, these technologies require a systematic frequency planning scheme. Generally, cells are grouped in a cluster of 7 (N=7). Each cluster reuses the same frequency to maximize bandwidth efficiency. To further minimize the co-channel interference from adjacent clusters, sector antennas are used. A cell is typically sectorized into three sectors (K=3) to achieve rapid frequency reuse. The deployment practices include using the N=7, K=3 or using the N=4, K=6 frequency reuse scheme.

This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in the laboratory, corroborate that these faults can be detected, in the EPVA signature, by the identification of a spectral component at twice the fundamental supply frequency. On-site tests, conducted in a power generation plant and in a cement mill, demonstrate the effectiveness of the EPVA in the detection of stator circuit faults in large industrial motors, rated up to 5 MW

Wheat germ agglutinin (WGA) lectin is a model compound for the interaction between viruses and cells during infection events and thus an interesting analyte for mass-sensitive sensing to study these interaction phenomena. Scanning tunneling microscopy studies reveal that surface molecular imprinting leads to cavities having the dimensions of WGA dimers. These reincorporate WGA from phosphatebuffered saline between 1 and 160 μg/ml. Whereas the quartz crystal microbalance (QCM) frequency for molecularly imprinted polymer (MIP)-coated electrodes decreases, indicating uptake of the analyte, their nonimprinted counterparts yield positive, concentration-dependent frequency shifts characteristic for slip of the analyte on the QCM surface. The MIPs achieve selectivity factors towards bovine serum albumin of roughly 4 at higher protein concentrations. Brunauer-Emmett-Teller analysis reveals that binding is favored by 29 kJ/mol until the adsorption of up to ten monolayers on the MIP, whereas above this range the value is lower. Together with the binding behavior of MIP and nonimprinted polymers, this indicates that the MIP acts as a nucleus for multilayer deposition onto the surface.

Resuhs: Eleven faculty, 11 resident physicians, and 13 emergency nurses were observed. Of 409 total contacts, 272 were clean, 46 were dirty, and 91 were gloved. Hand washing occurred after 32.3% of total contacts (SD, 2.31%). Nurses washed after 58.2% of 146 contacts (SD, 4.1%), residents after 18.6% of 129 contacts (SD, 3.4%), and faculty after t7.2% of 134 contacts (SD, 3.3%). Nurses had a significantly higher hand washing frequency than either faculty (P< .0001) or resident physicians (P< .0081). Hand washes occurred after 28.4% of 272 clean contacts (SO, 2.34%), which was significantly less (P< .0001) than 50.0% of 46 dirty contacts (SD, 7.4%) and 64.8% of 91 gloved contacts (SD, 5.0%).

The unique nature of the molecular structures of gas hydrates results in curious acoustic properties which have yet to be adequately characterized. Understanding the acoustic behavior of hydrates in liquids, in bubbly liquids, and in sediments containing liquids and/or gas is vital for surveying their location using seismic or echosounding techniques and may become a key tool for monitoring hydrate dissociation and its possible link to climate change. Acoustic properties of gassy substances are known to have a strong dependence on excitation frequency; however, tabulated values of hydrate sound speeds are most often measured at high frequencies (>200 kHz) despite modern location methods which use frequencies below 100 kHz. This presentation details a laboratory experiment in which the dissociation pressures of natural structure I and structure II methane hydrate samples were determined by measuring their low-frequency acoustic velocity in a liquid as a function of hydrostatic pressure.

Experiments with an acoustooptic phase modulator for single-mode optical fibers are described. The device, which operates in the 500-MHz frequency range, uses a zinc oxide transducer sputter deposited on top of a gold fim evaporated on the fiber. The device was heat cooled and partially acoustically terminated by gallium, which was also used as the top electrode of the zinc oxide transducer. The maximum modulation observed on a 2-mm length of fiber was 2 rad with an input power of 2 W.

1] A parametric study is presented on the temporal evolution of the phase space density (PSD) of the outer radiation belt energetic electrons driven by the superluminous right-hand extraordinary (R-X) mode waves at the location L = 4.5. Bounce-averaged diffusion rates in pitch angle and momentum are calculated by varying the peak wave frequency, the wave normal angle distribution, and the wave latitudinal distribution. Those diffusion rates are used as inputs to solve a 2-D momentum-pitch angle diffusion equation. In particular, three cases are considered: momentum diffusion rates alone, momentum +pitch angle diffusion rates, and momentum +pitch angle +cross diffusion rates. Numerical results show that at 24 h, electron PSDs can enhance substantially for 1 MeV energy at higher pitch angles. Momentum diffusion dominates the dynamic evolution of energetic electrons, whereas the contribution of pitch angle or cross-diffusion rates is insignificant using the specified wave model. In addition, PSD evolutions are sensitively dependent on the assumed different wave normal angle distributions and tend to be located in lower pitch angles when wave normal angles move to smaller regions. Diffusion coefficients and PSD evolution are largely determined by the wave latitudinal distributions. High-latitude R-X mode waves primarily contribute to pitch angle scattering of energetic electrons, whereas equatorial (or lower latitude) R-X mode waves yield efficient acceleration of electrons. This result supports the previous findings that superluminous R-X mode waves potentially contribute to dramatic variation in the outer radiation belt electron dynamics under appropriate conditions.

This study investigates a task in which discrete and rhythmic movements are combined in a single-joint elbow rotation. Previous studies reported a tendency for the EMG burst associated with the discrete movement to occur around the expected burst associated with the rhythmic movement (e.g., [Exp. Brain Res. 99 (1994) 325; J. Neurol. Neurosurg. Psychiatry 40 (1977) 1129 Hum. Mov. Sci. 19 (2000) 627]). We document this interaction between discrete and rhythmic movements in different task variations and suggest a model consisting of rhythmic and discrete pattern generators that reproduces the major results. In the experiment, subjects performed single-joint elbow oscillatory movements (2 Hz). Upon a signal, they initiated a movement that consisted of a shift in the midpoint of the oscillation (MID), a shift in the amplitude of the oscillation (AMP), or a combination of both (MID + AMP). These shifting movements were performed either in a reaction time or in a self-paced fashion. The tendency for the EMG bursts associated with the discrete and rhythmic movements to synchronize was found similarly in all three tasks and instruction conditions, but the synchronization was most pronounced in the selfinitiated discrete movement. Reaction time was increased for the combined task (MID + AMP), indicating higher control demands due to a combination of discrete and rhythmic components. This EMG burst synchronization was reproduced in a model based on a half-center oscillator with activation signals that produce either rhythmic or discrete activity. This activity was interpreted as torques driving a simple limb model. Summation of discrete and rhythmic activation signals of the pattern generators was sufficient to simulate the EMG burst synchronization. Further, simulation data reproduced the modulation of the reaction time as a function of the phase of the discrete movement. D

UWB systems based on impulse radio have the potential to provide very high data rates over short distances. In this paper, a new pulse shape is presented that satisfies the FCC spectral mask. Using this pulse, the link budget is calculated to quantify the relationship between data rate and distance. It is shown that UWB can be a good candidate for high rate transmission over short ranges, with the capability for reliably transmitting 100 Mbps over distances at about 10 meters.

Mediante esta práctica calcularemos experimentalmente el valor de la constante de elasticidad (k), y el periodo (T) haciendo uso de la ley de Hooke y la ecuación del movimiento armónico simple de un resorte sometido a una fuerza, con estos datos se hallara el margen de error cometido en el laboratorio y así lograr aclarar los conceptos teóricos de la materia.

This paper reports experimental research undertaken to study the effect of variation of inter-electrode distance on the Electromyogram (EMG). The experiments were conducted on ten healthy subjects and they performed isometric contraction of their biceps of the right arm at 20, 50 and 80% of their maximal voluntary contraction (MVC). EMG was recorded using surface electrodes with the distance between the two active electrodes being 18 and 36mm. It has been observed that at low levels of muscle contraction there was no significant variation due to the change in the distance between the electrodes while at 50 and 80% of MVC there was a significant change in the amplitude of the EMG. Using Time-Frequency analysis of EMG, the study demonstrates a variation of the spectral content of the EMG with change in the IED. The study also has shown that there is a variation of the EMG with muscle contraction but that the comparison should be done if the distance between the electrodes has been kept constant.

A fully automated design methodology based on nonlinear response history analysis is proposed for the optimum seismic design of reinforced concrete (RC) structures. The conventional trial-and-error process is replaced by a structural optimization algorithm that serves as a search engine capable of locating the most efficient design in terms of cost and performance. Two variations of the proposed design methodology are introduced. The first approach treats the optimum design problem in a deterministic manner, while in the second variation the optimum design is sought in the framework of a reliability-based optimization problem. The reliability-based approach seems to be a more rational procedure since more meaningful design criteria that correlate better with the performance-based design concept can be adopted. Thus, the practice of using the mean annual frequency of a limit-state being exceeded to assess the candidate designs is compared with the use of deterministic criteria. Both ...

In this paper, we present an original image quality metric for open-loop transcoding architectures based on frequency selective transmission. The proposed metric computes the normalized HVS-weighted mean squared error (NWMSE) between the reference digital video compressed bitstream, and its transcoded version. This computation is performed directly from the quantized DCT coefficients of the compressed bitstream. The resulting MSE error is implicitly weighted by the HVS sensitivity by considering the MPEG perceptual coding properties. Finally, rate control and error propagation are also taken into account, in order to improve transcoded video quality assessment. Experimental results are given which show that the proposed NWMSE metric correlates well with a conventional WPSNR. This validates the proposed assumptions used for the NWMSE computation. The major advantage of the approach is its simplicity since it does not need to perform the complete decoding of the compressed bitstream. Hence, the NWMSE metric is highly suited for real-time video applications.

A theoretical study of possible neuromuscular incapacitation based on the application of high-intensity, ultrashort electric pulses is presented. The analysis is applied to a rat, but the approach is general and can be extended to any whole-animal and applies for any arbitrary pulse waveform. It is hypothesized that repeatable and reversible action potential blocks in nerves can be attained based on the electroporation mechanism. Our numerical studies are based on the Hodgkin-Huxley distributed circuit representation of nerves, and incorporate a nodal analysis for the time-dependent and volumetric perturbing potentials and internal electric fields in whole animals. The predictions are compared to actual 600-ns experimental reports on rats and shown to be in very good agreement. Effective strength-duration plots for neuromuscular incapacitation are also generated.

Subband all-pole modelling is a flexible, scalable, and powerful approach for parsimoniously modelling rational transfer functions. Its advantage lies in its ability to model frequency bands independently of one another, thereby resulting in lower model orders in each subband and an overall reduction in the required number of parameters. To alleviate discontinuities in the spectrum at subband boundaries, it is necessary to increase slightly the computational complexity of the problem by incorporating continuity constraints. Previous solutions for implementing these constraints have been formulated for mathematical tractability and convenience; however, they are approximate and introduce modelling artifacts. This paper outlines an exact solution to the constrained modelling problem by using Lagrangian multipliers. The modelling results improve on the approximate formulations previously published.

This paper describes the use of the Extended Park's Vector Approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in the laboratory, corroborate that these faults can be detected, in the EPVA signature, by the identification of a spectral component at twice the fundamental supply frequency. On-site tests, conducted in a power generation plant and in a cement mill, demonstrate the effectiveness of the EPVA in the detection of these faults in large industrial motors, rated up to 5 MW.

The potential of a ground-based microwave temperature profiler to combine full tropospheric profiling with highresolution profiling of the boundary layer is investigated. For that purpose, statistical retrieval algorithms that incorporate observations from different elevation angles and frequencies are derived from long-term radiosonde data. A simulation study shows the potential to significantly improve the retrieval performance in the lowest kilometer by combining angular information from relatively opaque channels with zenith-only information from more transparent channels. Observations by a state-of-the-art radiometer employed during the International Lindenberg Campaign for Assessment of Humidity and Cloud Profiling Systems and Its Impact on High-Resolution Modeling (LAUNCH) in Lindenberg, Germany, are used for an experimental evaluation with observations from a 99-m mast and radiosondes. The comparison not only reveals the high accuracy achieved by combining angular and spectral observations (overall, less than 1 K below 1.5 km), but also emphasizes the need for a realistic description of radiometer noise within the algorithm. The capability of the profiler to observe the height and strength of low-level temperature inversions is highlighted.

In this paper, we present a multiagent algorithm for the frequency assignment problem in cellular radio networks. The algorithm, that has been successfully applied to GSM networks, efficiently assigns frequencies to each radio cell satisfying the constraints given by a compatibility matrix.

AbstracCA new high-speed, programmable FIR filter is present, which is a multiplierless filter with CSD encoding coefficients. With this encoding scheme, the speed of filter is improved and the area is optimized. In order to make this filter more applicable, we employ a new programmable CSD encoding structure to make CSD coefficients programmable. In the end of this paper, we design a 10-bits, 18 taps video luminance filter with the filter structure we present. The completed filter core occupies 6.8x6.8 mm2 of silicon area in Wu-Xi Shanghua 0.6-pm 2P2M CMOS technology, and its maximum work frequency is 100MHz.

Expanded polystyrene (EPS) geofoam seismic buffers can be used to reduce earthquake-induced loads acting on rigid retaining wall structures. A numerical study was carried out to investigate the influence of wall height; EPS geofoam type, thickness, and stiffness; and excitation record on seismic buffer performance. The numerical simulations were carried out using a verified FLAC code. The influence of parameter values was examined by computing the maximum forces on the walls, the buffer compressive strains, and the relative efficiency of the buffer system. In general, the closer the predominant frequency of excitation to the fundamental frequency of the wall model, the greater the seismic loads and buffer compression. The choice of earthquake record is shown to affect the magnitude of maximum earth force and isolation efficiency. However, when the wall response for walls 3 to 9 m in height are presented in this study in terms of isolation efficiency, the data from scaled accelerogra...

Summary form only given. Telecommunications has continued to push optical fibers towards ever-more demanding applications-such as high bit rates, dense wavelength-division multiplexing (DWDM), and long distances-and in response there has been renewed interest in alternative fiber designs to lift fundamental limitations of silica fibers. A particularly exciting departure from traditional fibers are fibers based on photonic band gaps, forbidden frequency

Abstruct-A two-component Cole-Cole model was used to obtain statistically significant fits to 100-Hz-10-MHz impedance data for EMT-6 mouse tumors during the progressive histological changes induced by hyperthermia. The resulting fitting parameters were used to deconvolute and reconstruct the two dispersions which confer the predominant impedance features to this tissue. The time-dependent changes of these two dispersions were correlated with the concurrent, heat-induced morphological changes of the tumors' cells. The higher frequency dispersion (fc M 1 MHz) was identified with a Maxwell-Wagner relaxation process linked to the overall volume response of the cells. The lower frequency dispersion (fc % 10 kHz) represented an alpharelaxation associated with the surface morphology and integrity of the plasma membranes. Thus, two aspects of the characteristic cellular damage sequence in these tumors were found to be separately discernable and trackable in real-time using the impedance data.