scholarly journals High frequency GPS bursts and path-level analysis reveal linear feature tracking by red foxes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Richard Bischof ◽  
Jon Glenn Omholt Gjevestad ◽  
Andrés Ordiz ◽  
Katrine Eldegard ◽  
Cyril Milleret
Keyword(s):  
High Frequency ◽  
Feature Tracking ◽  
Red Foxes ◽  
Linear Feature ◽  
Level Analysis

scholarly journals VLA Polarization Observation of the Radio Arc at 15 Ghz

1989 ◽  
Vol 136 ◽  
pp. 269-274 ◽  
Author(s):  
M. Inoue ◽  
E. Fomalont ◽  
M. Tsuboi ◽  
F. Yusef-Zadeh ◽  
M. Morris ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
High Spatial Resolution ◽  
Intrinsic Polarization ◽  
Linear Feature ◽  
Field System ◽  
Polarization Observation ◽  
Field Systems ◽  
Relativistic Particles ◽  
Accelerated Particles

Polarization measurements of the radio Arc were made with the VLA at 15 GHz. High frequency polarimetry made with high spatial resolution minimizes Faraday depolarization and reveals polarized filaments which correspond to the predominant filaments of the radio Arc. We notice a peculiar linear feature in the polarization map (“thorns”) which suggests the presence of a second magnetic field system. The total intensity maps show no evidence for an interaction between the two field systems, so the thorns may be foreground magnetized structures. However, if the two magnetic field systems do interact, it would allow a model in which the acceleration of relativistic particles takes place at their intersection. The accelerated particles would flow toward both ends of the radio Arc, and account for the intrinsic polarization observed along the entire length of the system. Thermal electrons responsible for the Faraday depolarization occuring at longer wavelengths may be supplied by the interaction of the streams of relativistic particles with relatively dense, ambient thermal clouds.

A Subsurface Geologic Feature Inferred from Relocation of Local Earthquakes in Al-Refaei District, Southern Iraq

2020 ◽  
Vol 54 (1A) ◽  
pp. 35-43
Author(s):  
Ali Ramthan
Keyword(s):  
High Frequency ◽  
Tectonic Setting ◽  
Arabian Plate ◽  
Stress Regime ◽  
Shallow Subsurface ◽  
Linear Feature ◽  
Recording Station ◽  
Communications System ◽  
System Power ◽  
Southern Iraq

For the last two decades, the District of Al-Refaei, southern Iraq, experienced several small to moderate size earthquakes that seem to be clustered in a relatively small area. The initial locations of these earthquakes from the available local and international bulletins show scattered events without any clear structural patterns. A seven-elements seismic array was installed for the period 2014 to 2018 to monitor this activity. Each element of the array consists of three-component Geospace GS11d high-frequency (4.5 Hz) geophone, a solar system power source, and telemetry communications system to transmit data to a central recording station. During the period of monitoring, the array recorded more than 56 earthquakes having a range of magnitude between 1.5 ML to 4.7 mb. Large number of the low magnitude earthquakes were not detected by other monitoring agencies; however, they were recorded by the array. Fifty-six of the most clearly recorded earthquakes were screened for relocation and analysis. Out of the 56 screened earthquakes, 35 were detected by the array alone. The majority of the selected earthquakes having their initial locations within the array. This improves the relocation process and increase accuracy. The relocated earthquakes express a clear pattern of a linear feature which strikes in the northwest-southeast direction. The direction of the newly inferred pattern coincides with the general tectonic setting of Iraq as it is parallel to Zagros suture zone and the general stress regime of the Arabian Plate. The depth of the relocated earthquakes ranges from about 3.9km to 8.9km. This indicates that these earthquakes occur along a shallow subsurface fault that was not mapped before.

scholarly journals A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor

2021 ◽  
Author(s):  
Mingyang Lu ◽  
Xiaobai Meng ◽  
Ruochen Huang ◽  
Liming Chen ◽  
Anthony Peyton ◽  
...  
Keyword(s):  
Magnetic Permeability ◽  
High Frequency ◽  
Impedance Measurement ◽  
Destructive Testing ◽  
Zero Crossing ◽  
Linear Feature ◽  
Signal Features ◽  
Fast Processing ◽  
Lift Off ◽  
Phase Term

Electromagnetic sensing has been used for diverse applications of non-destructive testing, including the surface inspection, measurement of properties, object characterization. However, the measurement accuracy could be significantly influenced by the lift-off between sensors and samples. To address the issue caused by lift-offs, various strategies have been proposed for the permeability measurement of ferromagnetic steels, which mainly involves different sensor designs and signal features (e.g., the zero-crossing feature). In this paper, a single high-frequency scenario for the permeability retrieval is introduced. By combining the signal of two sensing pairs, the retrieval of magnetic permeability is less affected by the lift-off of sensors. Unlike the previous strategy on reducing the lift-off effect (directly taking the phase term out of the integration) using the Dodd-Deeds analytical method, the proposed method is based on a high-frequency linear feature of the phase term. Therefore, this method has the merit of high accuracy and fast processing for the permeability retrieval (a simplified version of Dodd-Deeds analytical formulas after the integration). Experimental measurement has been carried out on the impedance measurement of designed sensors interrogating ferromagnetic dual-phase steels. For sensor lift-offs of up to 10 mm, the error of the permeability retrieval is controlled within 4 % under the optimal frequency.

Gene Expression Profiling of CML CD34+ Cells Prior to Imatinib Therapy Reveals Differences between Patients with and without Subsequent Complete Cytogenetic Response.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1222-1222
Author(s):  
L. C. Crossman ◽  
M. Loriaux ◽  
K. Vartanian ◽  
Y. Turpaz ◽  
R. Pillai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Gene Expression Profiling ◽  
Expression Profiling ◽  
High Frequency ◽  
Cytogenetic Response ◽  
Classification Models ◽  
Low Level ◽  
Cd34 Cells ◽  
Level Analysis

Abstract Background: Patients with chronic phase CML who achieve a complete cytogenetic response (CCR) have a low risk of disease progression. Since patients unlikely to achieve a CCR may benefit from more aggressive therapy, it would be clinically advantageous to identify those patients prior to therapy. Based on the hypothesis that cytogenetic refractoriness may be a property of leukemic progenitor cells, we explored the potential of gene expression profiling of CD34+ cells as a tool for predicting failure to achieve CCR. Methods: Fifty-one patients with CML who either achieved a CCR within 1 year of imatinib therapy (R, n = 35), or remained at least 65% Ph+ (NR, n = 16) were included in the study. Pre-imatinib CD34+ cells were FACS isolated from cryopreserved bone marrow mononuclear cells. RNA was extracted from the CD34+ cells and samples with >=5ng of high quality total RNA were amplified and labelled with the Affymetrix two cycle cDNA synthesis and IVT labeling protocol using <20ng input RNA; 10μg of labelled target cRNA were hybridized to Affymetrix HG-U133 Plus 2.0 GeneChip® arrays. Gene-by-gene ANOVA determined differential expression between NR and R. Low-level analysis was done using PLIER (Affymetrix) and RMA. Ranked p-values of n-way ANOVA results were used to select candidate classifiers and 90 classification models were tested. Best model selection and conserved accuracy estimate were done by 1 and 2 level nested cross validation respectively. Following hierarchical clustering and Principal Component Analysis (PCA), we identified the gene onotologies and associated pathways of the classifiers that had been selected in high frequency in the tested classification models. Results: The selection procedure yielded CD34+ cells with a median purity of 95.9% and median cell number of 1.0x104. Despite relatively low numbers of input cells, successful hybridization was achieved for 36 patients (24 R and 12 NR). Partial separation of NR and R was seen following hierarchical clustering and PCA, with R vs. NR being identified as a significant source of variation. Regardless of the specific low-level analysis approach, the classifiers performed similarly (conserved estimate of accuracy: 64% PLIER, 65% RMA). Certain biological pathways were associated with those classifiers who were selected in high frequency in the tested classification models (table). The majority of transcripts associated with these pathways were common to both low-level analysis methods, while additional unique transcripts for each pathway were identified with each method. Conclusions: (i) Gene expression profiling of CD34+ cells selected from cryopreserved bone marrow is feasible. (ii) This pilot study suggests that transcript profiling may have clinically useful predictive value in identifying patients unlikely to respond to imatinib. A larger study is needed to determine the predictive accuracy and obtain a clear understanding of the clinical relevance of those values. (iii) The classifiers are dominated by transcripts associated with PI3K and MAPK signalling, cell cycle, cell adhesion and nucleic acid metabolism. Pathway RMA Unique Transcripts PLIER Unique Transcripts Shared Transcripts Cell Cycle 4 1 14 Complement & Coagulation Cascades 8 2 9 Oxidative Phosphorylation 8 3 4 Phosphatidylinositol Signaling System 8 1 15 Purine Metabolism 9 2 13 Pyrimidine Metabolism 9 2 9

scholarly journals Minute Sea-Level Analysis (MISELA): a high-frequency sea-level analysis global dataset

2021 ◽  
Vol 13 (8) ◽  
pp. 4121-4132
Author(s):  
Petra Zemunik ◽  
Jadranka Šepić ◽  
Havu Pellikka ◽  
Leon Ćatipović ◽  
Ivica Vilibić
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Tide Gauge ◽  
Spatial Scales ◽  
Data Quality Control ◽  
Coastal Waves ◽  
Tidal Basins ◽  
Sea Level Oscillations ◽  
Control Procedures ◽  
Level Analysis

Abstract. Sea-level observations provide information on a variety of processes occurring over different temporal and spatial scales that may contribute to coastal flooding and hazards. However, global research on sea-level extremes is restricted to hourly datasets, which prevent the quantification and analyses of processes occurring at timescales between a few minutes and a few hours. These shorter-period processes, like seiches, meteotsunamis, infragravity and coastal waves, may even dominate in low tidal basins. Therefore, a new global 1 min sea-level dataset – MISELA (Minute Sea-Level Analysis) – has been developed, encompassing quality-checked records of nonseismic sea-level oscillations at tsunami timescales (T<2 h) obtained from 331 tide-gauge sites (https://doi.org/10.14284/456, Zemunik et al., 2021b). This paper describes data quality control procedures applied to the MISELA dataset, world and regional coverage of tide-gauge sites, and lengths of time series. The dataset is appropriate for global, regional or local research of atmospherically induced high-frequency sea-level oscillations, which should be included in the overall sea-level extremes assessments.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

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