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Fourier Analysis (0):
Recent article
Fourier Analysis
Abstract
We shall address. We shall point out the confusions about the conventional identity in the min-plus algebra and present an analytical expression of the asymptotic identity that may not cause confusions....
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PMID: 21822446
PDF is available here.
PDF is available here.
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Abstract
We discovered that heart rate variability was associated with the level of intelligence. The purpose of this study is to confirm this association using more reliable method and to define more precisely the frequency band within which the amplitude of the heart rate modulations is related to intellig...
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PMID: 21961308
PDF is available here.
PDF is available here.
Abstract
We studied the effect of exercise training on the density and spacing of left ventricle cardiomyocyte T-tubules in normal and remodeled hearts that associate with detubulation, by confocal laser scanning microscopy. First, exercise training in normal rats increased cardiomyocyte volume by 16% (P...
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PMID: 21660947
PDF is available here.
PDF is available here.
Abstract
This study explored a novel method for measuring cerebrovascular impedance to quantify the relationship between pulsatile changes in cerebral blood flow (CBF) and arterial pressure. Arterial pressure in the common carotid artery (CBP, applanation tonometry), CBF velocity in the middl...
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PMID: 21617082
PDF is available here.
PDF is available here.
Abstract
A single probe has limited brightness in time-domain imaging and such limitation frequently renders individual molecules undetectable in the presence of interference or complex cellular structures. However, a single photoswitchable probe produces a signal, which can be separated from interference or...
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PMID: 21539363
PDF is available here.
PDF is available here.
Abstract
The ultimate goal of quantitative ultrasound (QUS) imaging methods based on backscatter coefficient (BSC) estimates is to obtain system-independent structural information about samples. In the current study, three BSC estimation methods were compared and evaluated using the same backscattered pressur...
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PMID: 21568393
PDF is available here.
PDF is available here.
Abstract
Within the viscosity-extended Biot framework of wave propagation in porous media, the existence of a slow shear wave mode with non-vanishing velocity is predicted. It is a highly diffusive shear mode wherein the two constituent phases essentially undergo out-of-phase shear motions (slow shear wave)....
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PMID: 21568383
PDF is available here.
PDF is available here.
Abstract
The problem of high-resolution image volume reconstruction from reduced frequency acquisition sequences has drawn significant attention from the scientific community because of its practical importance in medical diagnosis. To address this issue, several reconstruction strategies have been recently p...
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PMID: 20729163
PDF is available here.
PDF is available here.
Abstract
We have developed what we believe to be a novel set of methods to characterize these undulations and extract the underlying profiles in the large systems. Our approach first obtains an undulation reference surface for each frame in the simulation and subsequently isolates the long-wavelength undulat...
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PMID: 21539778
PDF is available here.
PDF is available here.
Abstract
The measurement of lumbar spine motion is an important step for injury prevention research during complex and high impact activities, such as cricket fast bowling or javelin throwing. This study examined the performance of two designs of a lumbar rig, previously used in gait research, during a contro...
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PMID: 21576722
PDF is available here.
PDF is available here.
Abstract
This paper addresses depth discrimination of a water column target from bottom clutter discretes in wideband active sonar. To facilitate classification, the waveguide invariant property is used to derive multiple snapshots by uniformly sub-sampling the short-time Fourier transform (STFT) coefficients...
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PMID: 21476638
PDF is available here.
PDF is available here.
A theoretical comparison of attenuation measurement techniques from backscattered ultrasound echoes.
Abstract
Accurate characterization of tissue pathologies using ultrasonic attenuation is strongly dependent on the accuracy of the algorithm that is used to obtain the attenuation coefficient estimates. In this paper, computer simulations were used to compare the accuracy and the precision of the three method...
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PMID: 21476687
PDF is available here.
PDF is available here.
Abstract
Finite amplitude acoustic wave propagation through atmospheric turbulence is modeled using a Khokhlov-Zabolotskaya-Kuznetsov (KZK)-type equation. The equation accounts for the combined effects of nonlinearity, diffraction, absorption, and vectorial inhomogeneities of the medium. A numerical algorithm...
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PMID: 21476633
PDF is available here.
PDF is available here.
Abstract
A model is presented for the complete passive fathometer response to ocean surface noise, interfering discrete noise sources, and locally uncorrelated noise in an ideal waveguide. The leading order term of the ocean surface noise contribution produces the cross-correlation of vertical multipaths and...
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PMID: 21476639
PDF is available here.
PDF is available here.
Abstract
The transmission loss of sound through infinite orthogonally rib-stiffened double-panel structures having cavity-filling fibrous sound absorptive materials is theoretically investigated. The propagation of sound across the fibrous material is characterized using an equivalent fluid model, and the mot...
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PMID: 21476648
PDF is available here.
PDF is available here.
Abstract
The concept of a propagator is central to the angular spectrum formulation of diffraction theory, which expresses the pressure field diffracted by a two-dimensional aperture as a superposition of a continuum of plane waves. In the conventional form, an exponential term, known as a propagator, is mult...
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PMID: 21476660
PDF is available here.
PDF is available here.
Abstract
Abstract
The authors present a robust face recognition system for large-scale data sets taken under uncontrolled illumination variations. The proposed face recognition system consists of a novel illumination-insensitive preprocessing method, a hybrid Fourier-based facial feature extraction, and a score fusion...
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PMID: 20923738
PDF is available here.
PDF is available here.
Abstract
Compressed sensing (CS) has the potential to reduce magnetic resonance (MR) data acquisition time. In order for CS-based imaging schemes to be effective, the signal of interest should be sparse or compressible in a known representation, and the measurement scheme should have good mathematical propert...
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PMID: 20937579
PDF is available here.
PDF is available here.
Abstract
In this study a driving simulator was used to determine changes in mental effort in response to manipulations of steering demand. Changes in mental effort were assessed by using subjective effort ratings, physiology, and the standard deviation of the lateral position. Steering demand was increased by...
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PMID: 21376904
PDF is available here.
PDF is available here.
Abstract
Our aim was to ascertain whether the ultrasonic measurement of longitudinal corneal apex displacements carried out in a proper headrest is a credible method of ocular pulse (OP) detection. To distinguish between longitudinal movements of the eye globe treated as a rigid body and ocular surface expans...
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PMID: 21177153
PDF is available here.
PDF is available here.
Abstract
We study the effects of passive dendritic properties on the dynamics of neuronal oscillators. We find that the addition of a passive dendrite can sometimes have counterintuitive effects on firing frequency. Specifically, the addition of a hyperpolarized passive dendritic load can either increase, de...
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PMID: 21517524
PDF is available here.
PDF is available here.
Abstract
We consider control of reaction and population systems by imposing transitions between states with different numbers of particles or individuals. The transitions take place at predetermined instants of time. Even where they are significantly less frequent than spontaneous transitions, they can expon...
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PMID: 21517535
PDF is available here.
PDF is available here.
Abstract
We study the response of one-dimensional diffusive systems, consisting of particles interacting via symmetric or asymmetric exclusion, to time-periodic driving from two reservoirs coupled to the ends. The dynamical response of the system can be characterized in terms of the structure factor. We find...
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PMID: 21517462
PDF is available here.
PDF is available here.
Abstract
We propose a simple complexity indicator of classical Liouvillian dynamics, namely the separability entropy, which determines the logarithm of an effective number of terms in a Schmidt decomposition of phase space density with respect to an arbitrary fixed product basis. We show that linear growth o...
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PMID: 21517471
PDF is available here.
PDF is available here.
Abstract
Arterial elasticity has been proposed as an independent predictor of cardiovascular diseases and mortality. Identification of the different propagating modes in thin shells can be used to characterize the elastic properties. Ultrasound radiation force was used to generate local mecha...
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PMID: 21428498
PDF is available here.
PDF is available here.
Psychiatria Danubina (23)1 2011
Abstract
We assume that the initial neural event and feedback regulatory mechanisms that we can comprise with our models take place in the central brain structures. Here we demonstrate a refinement of the system identification procedure with skin conductance response signal, in order to test the thesis of th...
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PMID: 21448092
PDF is available here.
PDF is available here.
Medical Physics (38)3 2011
Abstract
Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital x-ray systems. Extensive works have been conducted to achieve accurate and precise measurement of NPS. One approach to improve the accuracy of the NPS measurement is to redu...
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PMID: 21520872
PDF is available here.
PDF is available here.
Abstract
Our data analysis also provides strong support for the notion that in the S(2) state the coordination of the Mn(III) ion is square-pyramidal (5-coordinate) or octahedral (6-coordinate) with tetragonal elongation. In addition, it is shown that only one of the currently published OEC models, the Siegb...
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PMID: 21341708
PDF is available here.
PDF is available here.
Abstract
We have tested this technique on 380 retina images from healthy individuals aged 50+ years, randomly selected from the Blue Mountains Eye Study population. To assess its reliability in assessing retinal vascular fractals from different allocation of optic center, we performed pair-wise Pearson corre...
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PMID: 20851791
PDF is available here.
PDF is available here.
Abstract
We developed a standardized approach for quantitative analysis of scar collagen morphology by confocal microscopy using fractal dimension and lacunarity analysis. Full-thickness wounds were created on adult mice, closed by primary intention, and harvested at 14 days after wounding for morphometrics...
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PMID: 21281794
PDF is available here.
PDF is available here.
Abstract
We hypothesize that screening mammograms obtained prior to the detection of cancer could contain subtle signs of early stages of breast cancer, in particular, architectural distortion. The methods are based upon Gabor filters, phase portrait analysis, a novel method for the analysis of the angular s...
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PMID: 20851789
PDF is available here.
PDF is available here.
Abstract
We present a modified Cartesian feedback technique called "frequency-offset Cartesian feedback" (FOCF) that significantly reduces these problems. In the FOCF architecture, the feedback control is performed at a low intermediate frequency rather than dc, so that quadrature ghosts and dc errors are sh...
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PMID: 20959264
PDF is available here.
PDF is available here.
Abstract
We report on novel cross-validating optoacoustic methods for measuring the frequency response of wideband acoustic sensors. The approach developed does not require pre-calibrated hydrophones and therefore can be readily adopted in any existing optoacoustic measurement configuration. The methods are...
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PMID: 21342817
PDF is available here.
PDF is available here.
Abstract
The purpose of this study has been to describe motor activity data obtained by using wrist-worn actigraphs in patients with schizophrenia and major depression by the use of linear and non-linear methods of analysis. Different time frames were investigated, i.e., activity counts measured every minute...
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PMID: 21297977
PDF is available here.
PDF is available here.
Abstract
We conducted an integrative analysis of time series transcriptomics and metabolomics data of Escherichia coli generated by cDNA microarray and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS), respectively. We identified a 60-min time lag between transition points of transcrip...
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PMID: 20863252
PDF is available here.
PDF is available here.
Abstract
Abstract A new system for nasal sound analysis via Internet to cellular phone was investigated. Spectral analysis of the nasal sound with frequency domain and dB is an important factor in the investigation of nasal airflow pattern. This study included 10 patients and 10 healthy subjects. Patients un...
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PMID: 21214305
PDF is available here.
PDF is available here.
Abstract
We for the first time utilize atomic force microscopy (AFM) to investigate nipple arrays of the Drosophila lens, achieving an unprecedented visualization of the architecture of these nanostructures. We find by Fourier analysis that the nipple arrays of Drosophila are disordered, and that the seeming...
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PMID: 21811578
PDF is available here.
PDF is available here.
Abstract
Modelling in systems biology often builds on the study of time-dependent phenomena. Fourier Transforms are a convenient tool for analysing the frequency domain of time series. However, there are well-known limitations of this method, such as the introduction of spurious frequencies when handling sho...
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PMID: 21702910
PDF is available here.
PDF is available here.
Acta Biomaterialia (7)1 2011
Abstract
We describe the structural and functional properties of three-dimensional (3D) nerve guides fabricated from poly-ε-caprolactone (PCL) using the air gap electrospinning process. This process makes it possible to deposit nano-to-micron diameter fibers into linear bundles that are aligned in parallel...
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PMID: 20727992
PDF is available here.
PDF is available here.
Abstract
A new method for estimation of EEG synchronism based on the analysis of correlation between amplitude modulation processes (envelopes) is considered. The efficiency of the given method is shown in different aspects: for detection of a topographical pattern, for analysis in frequency...
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PMID: 21961323
PDF is available here.
PDF is available here.
Abstract
Power spectra of cortical potentials of baseline activity during interstimuli intervals (4 s; Fourier transform in the frequency band of 1-60 Hz) and short-term (0.8 s) induced responses to facial stimuli (wavelet transform in the 15-60 Hz band) were assessed in the study of the visual cognitive set...
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PMID: 21950084
PDF is available here.
PDF is available here.
Abstract
We present a novel method for ultrasound backscatter image formation wherein lateral resolution of the target is obtained by using traveling shear waves to encode the lateral position of targets in the phase of the received echo. We demonstrate that the phase modulation as a function of shear wavenu...
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PMID: 21244978
PDF is available here.
PDF is available here.
Abstract
We present two approaches, one based on hardware and the other based on software. We compare the time they each take to achieve similar results and discuss the computational resources and form of blur model that each requires....
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PMID: 21244991
PDF is available here.
PDF is available here.
Abstract
Optical coherence tomography (OCT) is a non-destructive, non-invasive imaging modality conceptually similar to ultrasound imaging but uses near-infrared radiation rather than sound. It is attracting interest throughout the medical community as a tool for ophthalmic scanning (especially of the retina...
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PMID: 21042978
PDF is available here.
PDF is available here.
Abstract
We use level set propagation to capture the left ventricle boundaries. The proposed approach uses a new speed term based on local phase and local orientation derived from the monogenic signal, which makes the algorithm robust to attenuation artifact. Furthermore, we use Cauchy kernels, as a better a...
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PMID: 21216695
PDF is available here.
PDF is available here.
Clinical Neurophysiology (121)12 2010
Abstract
An analysis of EEG synchrony between homologous early visual areas tested the hypothesis that interhemispheric functional connectivity during visual stimulation is reduced in children with autism compared to controls.
EEG power and coherence within and between two homologous regions of the occipital...
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PMID: 20605520
PDF is available here.
PDF is available here.
Abstract
We conducted a Fourier analysis on data obtained using correlation and principal component analyses of parallel-standardized dental study models; both maxillary and mandibular dental arches were predominantly round square in shape. The present study compared and determined the contribution ratio and...
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PMID: 21174937
PDF is available here.
PDF is available here.
Abstract
We examine a unique patient cohort that has undergone decompressive hemicraniectomy, a surgical procedure wherein a portion of the calvaria is removed for several months during which time the scalp overlies the brain without intervening bone. We quantify the differences in signals between electrodes...
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PMID: 19925193
PDF is available here.
PDF is available here.
Medical Physics (37)11 2010
Abstract
The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast s...
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PMID: 21158316
PDF is available here.
PDF is available here.
Medical Physics (37)11 2010
Abstract
The authors report a noninvasive technique and instrumentation for visualizing vasculature in the breast in three dimensions without using either ionizing radiation or exogenous contrast agents, such as iodine or gadolinium. Vasculature is visualized by virtue of its high hemoglobin content compared...
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PMID: 21158321
PDF is available here.
PDF is available here.
Abstract
To better understand the processing of complex high-frequency sounds, modulation-detection thresholds were measured for sinusoidal frequency modulation (SFM), quasi-frequency modulation (QFM), sinusoidal amplitude modulation (SAM), and random-phase FM (RPFM). At the lowest modulation frequency (5 Hz...
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PMID: 20968328
PDF is available here.
PDF is available here.
Abstract
We describe an automated system to identify follicles in IHC-stained tissue sections. A unique feature of the system described here is the use of texture and color information to mimic the process that a human expert might use to identify follicle regions. Comparison of system-generated results with...
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PMID: 20639174
PDF is available here.
PDF is available here.
Abstract
Abstract
[1] the similarity in cranial vault shape between H. erectus and H. neanderthalensis suggests a single gradually evolving lineage; [2] The taxon H. heidelbergensis can be embedded into the H. erectus→H. neanderthalensis line; and [3] H. sapiens seems to be a separate evolutionary development and i...
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PMID: 20801442
PDF is available here.
PDF is available here.
Applied Optics (49)28 2010
Abstract
We developed a method for immobilization of biomolecules onto thiol functionalized surfaces according to UV diffraction patterns. UV light-assisted molecular immobilization proceeds through the formation of free, reactive thiol groups that can bind covalently to thiol reactive surfaces. We demonstra...
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PMID: 20885470
PDF is available here.
PDF is available here.
Optics Express (18)20 2010
Abstract
We demonstrate that the cavity resonance frequency - the round-trip frequency - of Terahertz quantum cascade lasers can be injection-locked by direct modulation of the bias current using an RF source. Metal-metal and single-plasmon waveguide devices with roundtrip frequencies up to 35GHz have been s...
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PMID: 20940975
PDF is available here.
PDF is available here.
Optics Express (18)20 2010
Abstract
We carry out a complete spatio-temporal characterization of the electric field of an ultrashort laser pulse after passing through a diffractive optical element composed of several binary amplitude concentric rings. Analytical expressions for the total diffraction field in the time and spectral domai...
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PMID: 20940985
PDF is available here.
PDF is available here.
Optics Express (18)20 2010
Abstract
Clean 7.5 fs pulses at 400 nm with less than 3% energy in tiny satellite pulses were obtained by spectral broadening in a hollow fiber and dispersive compensating using a prism pair together with a deformable mirror system. As an example, this stable and clean pulse was used to study the ultrafast p...
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PMID: 20940959
PDF is available here.
PDF is available here.
Optics Express (18)20 2010
Abstract
We present an analytical singular-value decomposition of a tomosynthesis system, which provides the measurement component of any given object. The method is demonstrated on an example object. The measurement component can be used as a reconstruction of the object, and can also be utilized in future...
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PMID: 20940966
PDF is available here.
PDF is available here.