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Sample records for absorption rate sar

  1. A Prototype RF Dosimeter for Independent Measurement of the Average Specific Absorption Rate (SAR) During MRI

    PubMed Central

    Stralka, John P; Bottomley, Paul A

    2008-01-01

    Purpose To develop a scanner-independent dosimeter for measuring the average radio frequency (RF) power deposition and specific absorption rates (SAR) for human MRI exposure. Materials and Methods A prototype dosimeter has a transducer with orthogonal conducting loops surrounding a small signal-generating MRI sample. The loops contain resistors whose values are adjusted to load the scanner’s MRI coils equivalent to an average head or body during MRI. The scanner adjusts its power output to normal levels during setup, using the MRI sample. Following calibration, the total power and average SAR deposited in the transducer are measured from the root-mean-square (rms) power induced in the transducer during MRI. Results A 1.5 Tesla head transducer was adjusted to elicit the same load as the average of nine adult volunteers. Once adjusted, the transducer loads other head coils the same as the head does. The dosimeter is calibrated at up to 20 W total deposited power and 4.5 W/kg SAR in the average head, with about 5% accuracy. Conclusion This dosimeter provides a simple portable means of measuring the power deposited in a body-equivalent sample load, independent of the scanner. Further work will develop SAR dosimetry for the torso and for higher fields. PMID:17969145

  2. Combined Acquisition Technique (CAT) for Neuroimaging of Multiple Sclerosis at Low Specific Absorption Rates (SAR)

    PubMed Central

    Biller, Armin; Choli, Morwan; Blaimer, Martin; Breuer, Felix A.; Jakob, Peter M.; Bartsch, Andreas J.

    2014-01-01

    Purpose To compare a novel combined acquisition technique (CAT) of turbo-spin-echo (TSE) and echo-planar-imaging (EPI) with conventional TSE. CAT reduces the electromagnetic energy load transmitted for spin excitation. This radiofrequency (RF) burden is limited by the specific absorption rate (SAR) for patient safety. SAR limits restrict high-field MRI applications, in particular. Material and Methods The study was approved by the local Medical Ethics Committee. Written informed consent was obtained from all participants. T2- and PD-weighted brain images of n = 40 Multiple Sclerosis (MS) patients were acquired by CAT and TSE at 3 Tesla. Lesions were recorded by two blinded, board-certificated neuroradiologists. Diagnostic equivalence of CAT and TSE to detect MS lesions was evaluated along with their SAR, sound pressure level (SPL) and sensations of acoustic noise, heating, vibration and peripheral nerve stimulation. Results Every MS lesion revealed on TSE was detected by CAT according to both raters (Cohen’s kappa of within-rater/across-CAT/TSE lesion detection κCAT = 1.00, at an inter-rater lesion detection agreement of κLES = 0.82). CAT reduced the SAR burden significantly compared to TSE (p<0.001). Mean SAR differences between TSE and CAT were 29.0 (±5.7) % for the T2-contrast and 32.7 (±21.9) % for the PD-contrast (expressed as percentages of the effective SAR limit of 3.2 W/kg for head examinations). Average SPL of CAT was no louder than during TSE. Sensations of CAT- vs. TSE-induced heating, noise and scanning vibrations did not differ. Conclusion T2−/PD-CAT is diagnostically equivalent to TSE for MS lesion detection yet substantially reduces the RF exposure. Such SAR reduction facilitates high-field MRI applications at 3 Tesla or above and corresponding protocol standardizations but CAT can also be used to scan faster, at higher resolution or with more slices. According to our data, CAT is no more uncomfortable than TSE scanning. PMID

  3. Assessment of specific energy absorption rate (SAR) in the head from a TETRA handset.

    PubMed

    Dimbylow, Peter; Khalid, Mohammed; Mann, Simon

    2003-12-01

    Finite-difference time-domain (FDTD) calculations of the specific energy absorption rate (SAR) from a representative TETRA handset have been performed in an anatomically realistic model of the head. TETRA (Terrestrial Trunked Radio) is a modern digital private mobile radio system designed to meet the requirements of professional users, such as the police and fire brigade. The current frequency allocations in the UK are 380-385 MHz and 390-395 MHz for the public sector network. A comprehensive set of calculations of SAR in the head was performed for positions of the handset in front of the face and at both sides of the head. The representative TETRA handset considered. operating at 1 W in normal use, will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a monopole antenna operating at 3 W in normal use will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a helical antenna operating at 3 W in normal use will show compliance with the ICNIRP occupational exposure restriction but will be over the public exposure restriction by up to approximately 50% if kept in the position of maximum SAR for 6 min continuously. PMID:14703166

  4. Resonance behaviour of whole-body averaged specific energy absorption rate (SAR) in the female voxel model, NAOMI

    NASA Astrophysics Data System (ADS)

    Dimbylow, Peter

    2005-09-01

    Finite-difference time-domain (FDTD) calculations have been performed of the whole-body averaged specific energy absorption rate (SAR) in a female voxel model, NAOMI, under isolated and grounded conditions from 10 MHz to 3 GHz. The 2 mm resolution voxel model, NAOMI, was scaled to a height of 1.63 m and a mass of 60 kg, the dimensions of the ICRP reference adult female. Comparison was made with SAR values from a reference male voxel model, NORMAN. A broad SAR resonance in the NAOMI values was found around 900 MHz and a resulting enhancement, up to 25%, over the values for the male voxel model, NORMAN. This latter result confirmed previously reported higher values in a female model. The effect of differences in anatomy was investigated by comparing values for 10-, 5- and 1-year-old phantoms rescaled to the ICRP reference values of height and mass which are the same for both sexes. The broad resonance in the NAOMI child values around 1 GHz is still a strong feature. A comparison has been made with ICNIRP guidelines. The ICNIRP occupational reference level provides a conservative estimate of the whole-body averaged SAR restriction. The linear scaling of the adult phantom using different factors in longitudinal and transverse directions, in order to match the ICRP stature and weight, does not exactly reproduce the anatomy of children. However, for public exposure the calculations with scaled child models indicate that the ICNIRP reference level may not provide a conservative estimate of the whole-body averaged SAR restriction, above 1.2 GHz for scaled 5- and 1-year-old female models, although any underestimate is by less than 20%.

  5. Hand effect on head specific absorption rate (SAR) exposed by two realistic phone models

    NASA Astrophysics Data System (ADS)

    Keshvari, J.; Kivento, M.

    2013-04-01

    There have been some reports about possible effect of the hand presence on the head SAR if hand phantom is included in the measurements of the head SAR compliance assessment procedure. The objective of this computational study was to examine the reported effect by using realistic head models and realistic CAD based phone models. A commercially available FDTD based EM solver was used to carry out the computational work. Based on the results of this study considering the SAR values without hand phantom as reference, following conclusions can be made: 1. In general presence of the hand lead to significantly less conservative SAR values in the head for large majority of cases 2. For lower band GSM frequencies the presence of the hand decreases the head SAR up to ~70%. 3. For the upper band GSM frequencies the presence of the hand decreases the head SAR up to ~55%. Based on the results of this study the present SAR compliance protocol where hand phantom is not included leads to more conservative head SAR results compared to the cases where hand is included.

  6. Outdoor measurement of SAR (specific absorption rate) in a full-sized human model exposed to 29. 9 MHz in the near field

    SciTech Connect

    Olsen, R.G.; Griner, T.A.

    1989-01-01

    Localized and averaged specific absorption rates (SARs) were obtained in a full-size muscle-equivalent human model exposed to near-field 29.9-MHz irradiation at an outdoor facility. The model was positioned erect on a metallic groundplane 1.22 m (4 ft) from the base of a 10.8-m (35 ft) whip antenna with an input power of 1.0 kW. For whole-body SAR, a mean value of 0.83 W/kg was determined using two gradient-layer calorimeters in a twin-well configuration. The localized SARs at 12 body locations were measured using nonperturbing temperature probes and were highest in the ankle region. It is concluded that average SAR measurements in a full-size phantom are feasible using a twin-calorimeter approach; measurements in the field are practical when human-size (183 x 61 x 46 cm) calorimeters are used.

  7. Influence of information about specific absorption rate (SAR) upon customers' purchase decisions and safety evaluation of mobile phones.

    PubMed

    Wiedemann, Peter M; Schütz, Holger; Clauberg, Martin

    2008-02-01

    This study investigated whether the SAR value is a purchase-relevant characteristic of mobile phones for laypersons and what effect the disclosure of a precautionary SAR value has on laypersons' risk perception. The study consisted of two parts: Study part 1 used a conjoint analysis design to explore the relevance of the SAR value and other features of mobile phones for an intended buying decision. Study part 2 used an experimental, repeated measures design to examine the effect of the magnitude of SAR values and the disclosure of a precautionary SAR value on risk perception. In addition, the study included an analysis of prior concerns of the study participants with regard to mobile phone risks. Part 1 indicates that the SAR value has a high relevance for laypersons' purchase intentions. In the experimental purchase setting it ranks even before price and equipment features. The results of study part 2 show that providing information of a precautionary limit value does not influence risk perception. This result suggests that laypersons' underlying subjective "safety model" for mobile phones resembles more a "margin of safety" concept than a threshold concept. The latter observation holds true no matter how concerned the participants are. PMID:17935161

  8. A specific absorption rate prediction concept for parallel transmission MR.

    PubMed

    Graesslin, Ingmar; Homann, Hanno; Biederer, Sven; Börnert, Peter; Nehrke, Kay; Vernickel, Peter; Mens, Giel; Harvey, Paul; Katscher, Ulrich

    2012-11-01

    The specific absorption rate (SAR) is a limiting factor in high-field MR. SAR estimation is typically performed by numerical simulations using generic human body models. However, SAR concepts for single-channel radiofrequency transmission cannot be directly applied to multichannel systems. In this study, a novel and comprehensive SAR prediction concept for parallel radiofrequency transmission MRI is presented, based on precalculated magnetic and electric fields obtained from electromagnetic simulations of numerical body models. The application of so-called Q-matrices and further computational optimizations allow for a real-time estimation of the SAR prior to scanning. This SAR estimation method was fully integrated into an eight-channel whole body MRI system, and it facilitated the selection of different body models and body positions. Experimental validation of the global SAR in phantoms demonstrated a good qualitative and quantitative agreement with the predictions. An initial in vivo validation showed good qualitative agreement between simulated and measured amplitude of (excitation) radiofrequency field. The feasibility and practicability of this SAR prediction concept was shown paving the way for safe parallel radiofrequency transmission in high-field MR. PMID:22231647

  9. Synthetic aperture design for increased SAR image rate

    DOEpatents

    Bielek, Timothy P.; Thompson, Douglas G.; Walker, Bruce C.

    2009-03-03

    High resolution SAR images of a target scene at near video rates can be produced by using overlapped, but nevertheless, full-size synthetic apertures. The SAR images, which respectively correspond to the apertures, can be analyzed in sequence to permit detection of movement in the target scene.

  10. SPECIFIC ABSORPTION RATE DISTRIBUTIONS IN A HETEROGENEOUS MODEL OF THE HUMAN BODY AT RADIOFREQUENCIES

    EPA Science Inventory

    The electric field distribution of the rate of energy absorption referred to as the specific absorption rate (SAR) in a biological body is a complex function of several exposure parameters such as frequency, intensity of the incident field, polarization, source to object configur...

  11. Intelligent low rate compression of speckled SAR imagery

    SciTech Connect

    Ives, R.W.; Eichel, P.; Magotra, N.

    1997-05-01

    This paper describes a compression technique under development at Sandia National Laboratories for the compression of complex synthetic aperture radar (SAR) imagery at very low overall bit rates. The methods involved combine several elements of existing and new lossy and lossless compression schemes in order to achieve an overall compression ratio of large SAR scenes of at least 50:1, while maintaining reasonable image quality. It is assumed that the end user will be primarily interested in specific regions of interest within the image (called chips), but that the context in which these chips appear within the entire scene is also of importance to an image analyst. The term intelligent is used to signify an external cuer which locates the chips of interest.

  12. Specific absorption rate in models of man and monkey at 225 and 2000 MHz

    SciTech Connect

    Olsen, R.G.; Griner, T.A.

    1987-01-01

    Full-size models of a man and a rhesus monkey were exposed to radiofrequency (RF) radiation at 225 MHz. The model of man was also exposed to 2000 MHz. Specific absorption rates (SARs) were measured in partial-body sections, such as the arms, legs, etc., using gradient-layer calorimeters. Also, front-surface thermographic images were obtained to qualitatively show the heating patterns. For all of the configurations used, the SAR in the limbs was much higher than in the torso. Agreement (whole-body SARs) with spheroidal models was better for both models at 225 MHz than at 2000 MHz. These results indicate that in the frequency range two orders of magnitude above whole-body resonance, SAR in the limbs significantly contributes to the whole-body average SAR.

  13. Design of Miniaturized Double-Negative Material for Specific Absorption Rate Reduction in Human Head

    PubMed Central

    Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2014-01-01

    In this study, a double-negative triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The specific absorption rate (SAR) reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the double-negative TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 52.28% reduction for the 10 g SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a mobile phone. PMID:25350398

  14. Quantifying intra- and extracellular aggregation of iron oxide nanoparticles and its influence on specific absorption rate.

    PubMed

    Jeon, Seongho; Hurley, Katie R; Bischof, John C; Haynes, Christy L; Hogan, Christopher J

    2016-09-21

    A promising route to cancer treatment is hyperthermia, facilitated by superparamagnetic iron oxide nanoparticles (SPIONs). After exposure to an alternating external magnetic field, SPIONs generate heat, quantified by their specific absorption rate (SAR, in W g(-1) Fe). However, without surface functionalization, commercially available, high SAR SPIONs (EMG 308, Ferrotec, USA) aggregate in aqueous suspensions; this has been shown to reduce SAR. Further reduction in SAR has been observed for SPIONs in suspensions containing cells, but the origin of this further reduction has not been made clear. Here, we use image analysis methods to quantify the structures of SPION aggregates in the extra- and intracellular milieu of LNCaP cell suspensions. We couple image characterization with nanoparticle tracking analysis and SAR measurements of SPION aggregates in cell-free suspensions, to better quantify the influence of cellular uptake on SPION aggregates and ultimately its influence on SAR. We find that in both the intra- and extracellular milieu, SPION aggregates are well-described by a quasifractal model, with most aggregates having fractal dimensions in the 1.6-2.2 range. Intracellular aggregates are found to be significantly larger than extracellular aggregates and are commonly composed of more than 10(3) primary SPION particles (hence they are "superaggregates"). By using high salt concentrations to generate such superaggregates and measuring the SAR of suspensions, we confirm that it is the formation of superaggregates in the intracellular milieu that negatively impacts SAR, reducing it from above 200 W g(-1) Fe for aggregates composed of fewer than 50 primary particles to below 50 W g(-1) for superaggregates. While the underlying physical mechanism by which aggregation leads to reduction in SAR remains to be determined, the methods developed in this study provide insight into how cellular uptake influences the extent of SPION aggregation, and enable estimation of the

  15. Parallel Transmission Pulse Design with Explicit Control for the Specific Absorption Rate in the Presence of Radiofrequency Errors

    PubMed Central

    Martin, Adrian; Schiavi, Emanuele; Eryaman, Yigitcan; Herraiz, Joaquin L.; Gagoski, Borjan; Adalsteinsson, Elfar; Wald, Lawrence L.; Guerin, Bastien

    2016-01-01

    Purpose A new framework for the design of parallel transmit (pTx) pulses is presented introducing constraints for local and global specific absorption rate (SAR) in the presence of errors in the radiofrequency (RF) transmit chain. Methods The first step is the design of a pTx RF pulse with explicit constraints for global and local SAR. Then, the worst possible SAR associated with that pulse due to RF transmission errors (“worst-case SAR”) is calculated. Finally, this information is used to re-calculate the pulse with lower SAR constraints, iterating this procedure until its worst-case SAR is within safety limits. Results Analysis of an actual pTx RF transmit chain revealed amplitude errors as high as 8% (20%) and phase errors above 3° (15°) for spokes (spiral) pulses. Simulations show that using the proposed framework, pulses can be designed with controlled “worst-case SAR” in the presence of errors of this magnitude at minor cost of the excitation profile quality. Conclusion Our worst-case SAR-constrained pTx design strategy yields pulses with local and global SAR within the safety limits even in the presence of RF transmission errors. This strategy is a natural way to incorporate SAR safety factors in the design of pTx pulses. PMID:26147916

  16. Analysis of the role of lead resistivity in specific absorption rate for deep brain stimulator leads at 3T MRI.

    PubMed

    Angelone, Leonardo M; Ahveninen, Jyrki; Belliveau, John W; Bonmassar, Giorgio

    2010-04-01

    Magnetic resonance imaging (MRI) on patients with implanted deep brain stimulators (DBSs) can be hazardous because of the antenna-effect of leads exposed to the incident radio-frequency field. This study evaluated electromagnetic field and specific absorption rate (SAR) changes as a function of lead resistivity on an anatomically precise head model in a 3T system. The anatomical accuracy of our head model allowed for detailed modeling of the path of DBS leads between epidermis and the outer table. Our electromagnetic finite difference time domain (FDTD) analysis showed significant changes of 1 g and 10 g averaged SAR for the range of lead resistivity modeled, including highly conductive leads up to highly resistive leads. Antenna performance and whole-head SAR were sensitive to the presence of the DBS leads only within 10%, while changes of over one order of magnitude were observed for the peak 10 g averaged SAR, suggesting that local SAR values should be considered in DBS guidelines. With rho(lead) = rho(copper) , and the MRI coil driven to produce a whole-head SAR without leads of 3.2 W/kg, the 1 g averaged SAR was 1080 W/kg and the 10 g averaged SAR 120 W/kg at the tip of the DBS lead. Conversely, in the control case without leads, the 1 g and 10 g averaged SAR were 0.5 W/kg and 0.6 W/kg, respectively, in the same location. The SAR at the tip of lead was similar with electrically homogeneous and electrically heterogeneous models. Our results show that computational models can support the development of novel lead technology, properly balancing the requirements of SAR deposition at the tip of the lead and power dissipation of the system battery. PMID:20335090

  17. Comparison of FDTD-calculated specific absorption rate in adults and children when using a mobile phone at 900 and 1800 MHz

    NASA Astrophysics Data System (ADS)

    Martínez-Búrdalo, M.; Martín, A.; Anguiano, M.; Villar, R.

    2004-01-01

    In this paper, the specific absorption rate (SAR) in scaled human head models is analysed to study possible differences between SAR in the heads of adults and children and for assessment of compliance with the international safety guidelines, while using a mobile phone. The finite-difference time-domain method (FDTD) has been used for calculating SAR values for models of both children and adults, at 900 and 1800 MHz. Maximum 1 g averaged SAR (SAR1 g) and maximum 10 g averaged SAR (SAR10 g) have been calculated in adults and scaled head models for comparison and assessment of compliance with ANSI/IEEE and European guidelines. Results show that peak SAR1 g and peak SAR10 g all trend downwards with decreasing head size but as head size decreases, the percentage of energy absorbed in the brain increases. So, higher SAR in children's brains can be expected depending on whether the thickness of their skulls and surrounding tissues actually depends on age. The SAR in eyes of different sizes, as a critical organ, has also been studied and very similar distributions for the full size and the scaled models have been obtained. Standard limits can only be exceeded in the unpractical situation where the antenna is located at a very short distance in front of the eye.

  18. Motion measurement of SAR antenna based on high frame rate camera

    NASA Astrophysics Data System (ADS)

    Li, Q.; Cao, R.; Feng, H.; Xu, Z.

    2015-03-01

    Synthetic Aperture Radar (SAR) is currently in the marine, agriculture, geology and other fields are widely used, while the SAR antenna is one of the most important subsystems. Performance of antenna has a significant impact on the SAR sensitivity, azimuth resolution, image blur degree and other parameter. To improve SAR resolution, SAR antenna is designed and fabricated according to flexible expandable style. However, the movement of flexible antenna will have a greater impact on accuracy of SAR systems, so the motion measurement of the flexible antenna is an urgent problem. This paper studied motion measurements method based on high frame rate camera, designed and completed a flexible antenna motion measurement experiment. In the experiment the main IMU and the sub IMU were placed at both ends of the cantilever, which is simulation of flexible antenna, the high frame rate camera was placed above the main IMU, and the imaging target was set on side of the sub IMU. When the cantilever motion occurs, IMU acquired spatial coordinates of cantilever movement in real-time, and high frame rate camera captured a series of target images, and then the images was input into JTC to obtain the cantilever motion coordinates. Through the contrast and analysis of measurement results, the measurement accuracy of flexible antenna motion is verified.

  19. Application of pixel segmentation to the low rate compression of complex SAR imagery

    SciTech Connect

    Ives, R.W.; Eichel, P.; Magotra, N.

    1998-03-01

    This paper describes a technique to identify pixels within a subregion (chip) of a complex or detected SAR image which are to be losslessly compressed while the remainder of the image is subjected to a high compression ratio. This multi-modal compression is required for the intelligent low rate compression of SAR imagery, which addresses the problem of transmitting massive amounts of high resolution complex SAR data from a remote airborne sensor to a ground station for exploitation by an automatic target recognition (ATR) system, in a real time environment, over a narrow bandwidth. The ATR system results might then be presented to an image analyst who, using the contextual information from the SAR image, makes final target determination.

  20. SAR models for estimating the percutaneous absorption of polynuclear aromatic hydrocarbons.

    PubMed

    Roy, T A; Krueger, A J; Mackerer, C R; Neil, W; Arroyo, A M; Yang, J J

    1998-01-01

    A structure-activity relationship (SAR) of the in vitro percutaneous absorption of polycyclic aromatic hydrocarbons (PAH) is described. The data set consisted of 60 three to seven ring PAH. Over 50 numeric descriptors were generated from the modeled molecular structures. Computer aided methods were used to evaluate descriptors and develop linear expressions relating the percent of dermally applied PAH dose absorbed through skin (PADA) to PAH structure. Three regression models with one and two variables were developed. The log octanol/water partition coefficient (log P) was the most important variable in determining percutaneous absorption. An inverse relationship between log P and the skin penetration properties of the PAH was observed. Nearly 40 of 60 PAH tested had PADA-values within a factor of two of benzo[a]pyrene (BaP); well over 50 of 60 had PADA-values within a factor of three. The results lend support to the use of isotopically labeled BaP as a surrogate for measuring the dermal flux (in vivo and in vitro) and estimating the dermal bioavailability of PAH from complex mineral oil and coal-tar derived mixtures. PMID:9933958

  1. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Garaio, E.; Collantes, J. M.; Garcia, J. A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-11-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m-1. In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles.

  2. Patch diameter limitation due to high chirp rates in focused SAR images

    NASA Astrophysics Data System (ADS)

    Doerry, Armin W.

    1994-10-01

    Polar-format processed synthetic aperture radar (SAR) images have a limited focused patch diameter that results from unmitigated phase errors. Very high chirp rates, encountered with fine-resolution short-pulse radars, exasperate the problem via a residual video phase error term. This letter modifies the traditional maximum patch diameter expression to include effects of very high chirp rates.

  3. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz

    NASA Astrophysics Data System (ADS)

    Zamorano, M.; Torres-Silva, H.

    2006-04-01

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source.

  4. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz.

    PubMed

    Zamorano, M; Torres-Silva, H

    2006-04-01

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) "inverse skin effect" shows up at 1800 MHz, with respect to a 900 MHz source. PMID:16552096

  5. Specific absorption rate in electrically coupled biological samples between metal plates.

    PubMed

    Joines, W T; Blackman, C F; Spiegel, R J

    1986-01-01

    The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal-plate spacings by using the method of images and induced dipole coupling. For a decrease in metal-plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring-sample spacing. The calculations are compared with measurements made with the aid of an array of 1-in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations. PMID:3741491

  6. On the reliable measurement of specific absorption rates and intrinsic loss parameters in magnetic hyperthermia materials

    NASA Astrophysics Data System (ADS)

    Wildeboer, R. R.; Southern, P.; Pankhurst, Q. A.

    2014-12-01

    In the clinical application of magnetic hyperthermia, the heat generated by magnetic nanoparticles in an alternating magnetic field is used as a cancer treatment. The heating ability of the particles is quantified by the specific absorption rate (SAR), an extrinsic parameter based on the clinical response characteristic of power delivered per unit mass, and by the intrinsic loss parameter (ILP), an intrinsic parameter based on the heating capacity of the material. Even though both the SAR and ILP are widely used as comparative design parameters, they are almost always measured in non-adiabatic systems that make accurate measurements difficult. We present here the results of a systematic review of measurement methods for both SAR and ILP, leading to recommendations for a standardised, simple and reliable method for measurements using non-adiabatic systems. In a representative survey of 50 retrieved datasets taken from published papers, the derived SAR or ILP was found to be more than 5% overestimated in 24% of cases and more than 5% underestimated in 52% of cases.

  7. Comparison of specific absorption rate induced in brain tissues of a child and an adult using mobile phone

    NASA Astrophysics Data System (ADS)

    Lu, Mai; Ueno, Shoogo

    2012-04-01

    The steady increase of mobile phone usage, especially mobile phones by children, has led to a rising concern about the possible adverse health effects of radio frequency electromagnetic field exposure. The objective of this work is to study whether there is a larger radio frequency energy absorption in the brain of a child compared to that of an adult. For this reason, three high-resolution models, two child head models (6 - and 11-year old) and one adult head model (34-year old) have been used in the study. A finite-difference time-domain method was employed to calculate the specific absorption rate (SAR) in the models from exposure to a generic handset at 1750 MHz. The results show that the SAR distributions in the human brain are age-dependent, and there is a deeper penetration of the absorbed SAR in the child's brain. The induced SAR can be significantly higher in subregions of the child's brain. In all of the examined cases, the SAR values in the brains of a child and an adult are well below the IEEE safety standard.

  8. Bioelectromagnetic effects measurements - SAR and induced current.

    PubMed

    Dlugosz, Tomasz

    2015-01-01

    The paper discusses several theoretical and practical aspects of the application of currents flowing through the body of a radiotelephone operator and Specific Absorption Rate (SAR). SAR is known as the physical quantity which is a perfect solution for biological experiments. Unfortunately, SAR cannot be measured directly. Contrary to SAR, which is limited to the penetration depth, a current induced in a point of a body is measurable in any other point of the body. The main objective of this paper is to show that the current induced in a human body when using a radiotelephone or mobile phone is significant and should be analyzed as widely as SAR is. Computer simulations of a human's hand with a radiotelephone were made. Experiments were also conducted. The results of the experiments show that induced current is also as important as SAR and it cannot be omitted in bioelectromagnetic experiments. In biomedical studies both parameters: induced current and SAR play a major role. PMID:25585976

  9. Present knowledge about specific absorption rates inside a human body exposed to radiofrequency electromagnetic fields

    SciTech Connect

    Garn, J.; Gabriel, C.

    1995-02-01

    We have compiled results of scientific investigations about the relationship between external field-strengths and specific absorption rates inside the human body. The data were normalized to SAR-values that form the basis for current safety standards. Results were compared to exposure limits given in these standard. This comparison should serve as a reference for the selection of reliable reference levels for personal protection against thermal effects in radiofrequency electromagnetic fields. The need to measure and monitor ankle/wrist currents to protect some exposed workers is explained. The study has also highlighted a scarcity of dosimetric data at frequencies below 3 MHz. 20 refs., 7 figs.

  10. High intraspecific recombination rate in a native population of Candidatus pelagibacter ubique (SAR11).

    PubMed

    Vergin, Kevin L; Tripp, H James; Wilhelm, Larry J; Denver, Dee R; Rappé, Michael S; Giovannoni, Stephen J

    2007-10-01

    Recombination is an important process in microbial evolution. Rates of recombination with extracellular DNA matter because models of microbial population structure are profoundly influenced by the degree to which recombination is occurring within the population. Low rates of recombination may be sufficient to ensure the lateral propagation of genes that have a high selective advantage without disrupting the clonal pattern of inheritance for other genes. High rates of recombination potentially can obscure clonal patterns, leading to linkage equilibrium, and give microbial populations a population genetic structure more akin to sexually interbreeding eukaryotic populations. We examined eight loci from nine strains of candidatus Pelagibacter ubique (SAR11), isolated from a single 2L niskin sample of natural seawater, for evidence of genetic recombination between strains. The Shimodaira-Hasegawa test revealed significant phylogenetic incongruence in seven of the genes, indicating that frequent recombination obscures phylogenetic signals from the linear inheritance of genes in this population. Statistical evidence for intragenic recombination was found for six loci. An informative sites matrix showed extensive evidence for a widespread breakdown of linkage disequilibrium. Although the mechanisms of genetic transfer in native SAR11 populations are unknown, we measured recombination rates, rho, that are much higher than point mutation rates, theta, as a source of genetic diversity in this clade. The eukaryotic model of species sharing a common pool of alleles is more apt for this SAR11 population than a strictly clonal model of inheritance in which allelic diversity is controlled by periodic selection. PMID:17803769

  11. Inversion of InSAR Data for the Aseismic Slip-Rate on the Hayward Fault

    NASA Astrophysics Data System (ADS)

    Schmidt, D. A.; Bürgmann, R.; Nadeau, R.; D'Alessio, M.

    2002-12-01

    The Hayward fault is a major strand of the San Andreas fault system, and has received considerable attention because of the seismic hazard it poses to the San Francisco Bay Area. We perform a least-squares inversion of multiple geodetic and seismic data sets to determine the strike-slip distribution of the aseismic slip-rate on the fault. The analysis focuses on the northern 60 km of the fault where surface creep rates appear to be constant over the past several decades. InSAR data from 24 independent ERS interferograms are stacked to obtain range-change rates from 1992 to 2000. Surface displacement rates at 43 sites are observed using GPS from 1994 to 2002. Surface creep observations and estimates of deep slip rates determined from characteristic repeating earthquake sequences are also incorporated in the inversion. The densely spaced InSAR data require a non-planar fault surface to adequately model the near-fault data. The fault is discretized into 283 triangular dislocation elements that approximate the non-planar attributes of the fault surface. South of Hayward, a steeply, east-dipping fault geometry accommodates the divergence of the surface trace and the micro-seismicity at depth. Laplacian smoothing and a positivity constraint are included in the inversion. The InSAR data provide the greatest resolution on the shallow portion of the fault. The additional data sets help to complement the InSAR data and improve the model resolution. The inversion result suggests a heterogeneous distribution of aseismic slip-rate that is characterized by both locked and freely slipping patches. A seismic cluster beneath San Leandro coincides with a creeping patch as resolved by the geodetic data. A locked region at depth coincides with the source region of the 1868 earthquake (M 6.8) on the southern Hayward fault.

  12. Specific absorption rate dependence on temperature in magnetic field hyperthermia measured by dynamic hysteresis losses (ac magnetometry)

    NASA Astrophysics Data System (ADS)

    Garaio, Eneko; Sandre, Olivier; Collantes, Juan-Mari; Garcia, Jose Angel; Mornet, Stéphane; Plazaola, Fernando

    2015-01-01

    Magnetic nanoparticles (NPs) are intensively studied for their potential use for magnetic hyperthermia, a treatment that has passed a phase II clinical trial against severe brain cancer (glioblastoma) at the end of 2011. Their heating power, characterized by the ‘specific absorption rate (SAR)’, is often considered temperature independent in the literature, mainly because of the difficulties that arise from the measurement methodology. Using a dynamic magnetometer presented in a recent paper, we measure here the thermal dependence of SAR for superparamagnetic iron oxide (maghemite) NPs of four different size-ranges corresponding to mean diameters around 12 nm, 14 nm, 15 nm and 16 nm. The article reports a parametrical study extending from 10 to 60 {}^\\circ C in temperature, from 75 to 1031 kHz in frequency, and from 2 to 24 kA m-1 in magnetic field strength. It was observed that SAR values of smaller NPs decrease with temperature whereas for the larger sample (16 nm) SAR values increase with temperature. The measured variation of SAR with temperature is frequency dependent. This behaviour is fully explained within the scope of linear response theory based on Néel and Brown relaxation processes, using independent magnetic measurements of the specific magnetization and the magnetic anisotropy constant. A good quantitative agreement between experimental values and theoretical values is confirmed in a tri-dimensional space that uses as coordinates the field strength, the frequency and the temperature.

  13. Estimation of variability of specific absorption rate with physical description of children exposed to electromagnetic field in the VHF band.

    PubMed

    Nagaoka, T; Watanabe, S

    2009-01-01

    Recently, there has been an increasing concern regarding the effects of electromagnetic waves on the health of humans. The safety of radio frequency electromagnetic fields (RF-EMFs) is evaluated by the specific absorption rate (SAR). In recent years, SAR has been estimated by numerical simulation using fine-resolution and anatomically realistic reference whole-body voxel models of people of various ages. The variation in SAR with a change in the physical features of a real person is hardly studied, although every person has different physical features. In this study, in order to estimate the individual variability in SAR of persons, we obtained considerable 3D body shape data from actual three-year-old children and developed several homogeneous models of these children. The variability in SAR of the homogeneous models of three-year-old children for whole-body exposure to RF electromagnetic fields in the very high frequency (VHF) band calculated using the finite-difference time-domain method has been described. PMID:19964253

  14. The formation of linear aggregates in magnetic hyperthermia: implications on specific absorption rate and magnetic anisotropy.

    PubMed

    Saville, Steven L; Qi, Bin; Baker, Jonathon; Stone, Roland; Camley, Robert E; Livesey, Karen L; Ye, Longfei; Crawford, Thomas M; Mefford, O Thompson

    2014-06-15

    The design and application of magnetic nanoparticles for use as magnetic hyperthermia agents has garnered increasing interest over the past several years. When designing these systems, the fundamentals of particle design play a key role in the observed specific absorption rate (SAR). This includes the particle's core size, polymer brush length, and colloidal arrangement. While the role of particle core size on the observed SAR has been significantly reported, the role of the polymer brush length has not attracted as much attention. It has recently been reported that for some suspensions linear aggregates form in the presence of an applied external magnetic field, i.e. chains of magnetic particles. The formation of these chains may have the potential for a dramatic impact on the biomedical application of these materials, specifically the efficiency of the particles to transfer magnetic energy to the surrounding cells. In this study we demonstrate the dependence of SAR on magnetite nanoparticle core size and brush length as well as observe the formation of magnetically induced colloidal arrangements. Colloidally stable magnetic nanoparticles were demonstrated to form linear aggregates in an alternating magnetic field. The length and distribution of the aggregates were dependent upon the stabilizing polymer molecular weight. As the molecular weight of the stabilizing layer increased, the magnetic interparticle interactions decreased therefore limiting chain formation. In addition, theoretical calculations demonstrated that interparticle spacing has a significant impact on the magnetic behavior of these materials. This work has several implications for the design of nanoparticle and magnetic hyperthermia systems, while improving understanding of how colloidal arrangement affects SAR. PMID:24767510

  15. A map of strain rate for Eastern Turkey, from InSAR and GPS data

    NASA Astrophysics Data System (ADS)

    Walters, R. J.; Parsons, B.; Wright, T. J.

    2013-12-01

    Tectonic deformation in Eastern Turkey is dominated by strain localisation on two major strike-slip faults; the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF). Here we use Interferometric Synthetic Aperture Radar (InSAR) to map interseismic strain across the Eurasian-Arabian plate boundary zone in Eastern Turkey, covering both the NAF and the EAF. Most previous InSAR interseismic studies of the NAF have used only descending track data, and in these studies it was therefore necessary to assume purely horizontal, fault-parallel motion in modelling deformation. The slip rate of the EAF has been the focus of only a few geological and geodetic studies, and InSAR has not previously been used to measure interseismic strain accumulation across this fault. We construct ~400 Envisat interferograms on three descending and two ascending tracks in Eastern Turkey, covering both the NAF and EAF. We use these data to generate five line-of-sight velocity maps (ratemaps) using the PiRATE software package (Wang et al., GRL, 2009), which implements a multi-interferogram network approach in order to maximise spatial coverage and correct for orbital errors. We find that the five InSAR ratemaps agree best in overlapping regions when all interferograms are first corrected for atmospheric effects using model outputs from the ERA-Interim global atmospheric model (Jolivet et al., GRL, 2011). From these five overlapping ratemaps, we model elastic strain accumulation for both the NAF and EAF, and calculate slip rates of 20×3 mm/yr and 10×2 mm/yr respectively, with associated locking depths of 16×9 km and 13×4 km. We then use the ratemaps, together with a compilation of GPS data in the area, to calculate a velocity field for Eastern Turkey. We find that the velocity field derived from InSAR and GPS data significantly reduces the uncertainty of east-west velocities when compared with the velocity field derived from GPS data alone, and shows that strain is mainly localised

  16. The relationship of temperature rise to specific absorption rate and current in the human leg for exposure to electromagnetic radiation in the high frequency band.

    PubMed

    Wainwright, P R

    2003-10-01

    Of the biological effects of human exposure to radiofrequency and microwave radiation, the best-established are those due to elevation of tissue temperature. To prevent harmful levels of heating, restrictions have been proposed on the specific absorption rate (SAR). However, the relationship between SAR and temperature rise is not an invariant, since not only the heat capacity but also the efficiency of heat dissipation varies between different tissues and exposure scenarios. For small enough SAR, the relationship is linear and may be characterized by a 'heating factor' deltaT/SAR. Under whole-body irradiation the SAR may be particularly high in the ankles due to the concentration of current flowing through a relatively small cross-sectional area. In a previous paper, the author has presented calculations of the SAR distribution in a human leg in the high frequency (HF) band. In this paper, the heating factor for this situation is derived using a finite element approximation of the Pennes bioheat equation. The sensitivity of the results to different blood perfusion rates is investigated, and a simple local thermoregulatory model is applied. Both time-dependent and steady-state solutions are considered. Results confirm the appropriateness of the ICNIRP reference level of 100 mA on current through the leg, but suggest that at higher currents significant thermoregulatory adjustments to muscle blood flow will occur. PMID:14579857

  17. Measurements of ankle specific absorption rate and body-to-ground current in a suit-protected human model for near-field exposures, 2-400 MHz

    SciTech Connect

    Olsen, R.G.; Van Matre, B.J.

    1994-06-01

    The potential usefulness of a protective-suit ensemble to reduce specific absorption rate (SAR) at submicrowave frequencies was studied using a full-sized, muscle-equivalent human model. In the past, such suits were used predominantly for microwave protection, but some highly conductive suits presented a very real fire hazard when arcing was considered. Suits made from partially conductive fabric were slightly less effective against microwaves but were much less flammable; moreover, their performance against other radiofrequencies (RFs) has not been studied. Recently promulgated exposure standards have imposed theoretical maximum body-currents to limit extremity SAR to 20 W/kg and have impacted certain occupational environments such as those surrounding RF transmitting towers and RF heat sealers. In the present research, reactive near-field irradiation conditions were used at 2.025 and 29.9 MHz, and quasi-near-field conditions were used at 80.0 and 400.0 MHz. Nonperturbing thermal probes were used to measure RF-induced temperature rises from which localized ankle SARs were calculated; a stand-on RF milliammeter recorded RF body-to-ground current over metallic groundplanes. Mean ankle SARs of greater than 23 W/kg were measured for some unprotected conditions, but with full ensemble protection (suit, hood, and overshoes) no mean ankle SAR exceeded 1.1 W/kg. The suit without the overshoes, however, did not reduce ankle SAR. At 29.9 and 80.0 MHz, the presence or absence of the hood caused relatively small SAR changes. We attribute the suit`s ability in reducing ankle SAR to the partially conducting nature of the metal/textile material and to the ability of the overshoes to shunt RF current around the ankles. We recommend that further use of partially conducting fabrics be explored to provide practical means of reducing occupational RF-induced extremity SAR to acceptable levels. 16 refs., 2 figs., 1 tab.

  18. Specific absorption rate and electric field measurements in the near field of six mobile phone base station antennas.

    PubMed

    Toivonen, Tommi; Toivo, Tim; Puranen, Lauri; Jokela, Kari

    2009-05-01

    In this article, the exposure to radio frequency electromagnetic fields was studied in close proximity (distances of 10, 100, 300, and 600 mm) to six base station antennas. The specific absorption rate (SAR) in 800 mm x 500 mm x 200 mm box phantom as well as unperturbed electric field (E) in air was measured. The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure. Also, the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied. Moreover, the assessment of whole-body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole-body SAR. These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied. However, in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E, the exposure was overestimated only very slightly (by factor 1.1) compared to the basic restriction for localized SAR in a human, and hence these results can not be generalized to all antenna types. Moreover, it was shown that the limit for localized exposure could be exceeded before the limit for the whole-body average SAR, if the distance to the antenna was less than 240 mm. PMID:19194889

  19. Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field

    PubMed Central

    Kekalo, K.; Baker, I.; Meyers, R.; Shyong, J.

    2015-01-01

    This paper describes the synthesis and properties of a new type of magnetic nanoparticle (MNP) for use in the hyperthermia treatment of tumors. These particles consist of 2–4 nm crystals of gamma-Fe2O3 gathered in 20–40 nm aggregates with a coating of carboxymethyl-dextran, producing a zetasize of 110–120 nm. Despite their very low saturation magnetization (1.5–6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22–200 W/g at applied alternating magnetic field (AMF) with strengths of 100–500 Oe at a frequency of 160 kHz. PMID:26884816

  20. Localized specific absorption rate calculations in a realistic phantom leg at 1-30 MHz using a finite element method.

    PubMed

    Wainwright, P R

    1999-04-01

    Protection standards for radiofrequency electromagnetic radiation are principally intended to avoid detrimental thermal effects. To this end the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and national bodies such as the National Radiological Protection Board (NRPB), recommend limitations on the localized specific energy absorption rate (SAR) in various parts of the body. The role of numerical dosimetry is to estimate the SAR from measurable parameters such as external field strengths and total body currents. In recent years there have been significant advances in the sophistication of the anatomical models available, and in our knowledge of the electrical properties of the body tissues. Several groups, including NRPB, have developed mathematical phantoms from medical imaging data, such as MRI scans. It has been known for some time that under certain circumstances SAR restrictions may be violated in the ankle due to the concentration of current in a small area. In this paper the author presents calculations of the SAR distribution in a human leg in the high-frequency (HF) band. This band contains the human whole-body resonance frequency and therefore gives the strongest coupling of the body to the field. The present study uses a finite element model with variable mesh size, derived from a 2 mm resolution voxel phantom of the whole body. It also uses recently acquired data on the electrical properties of the tissues. The results are discussed in the light of the exposure standards promulgated by national and international bodies such as NRPB and ICNIRP, and it is shown that the basic SAR restrictions in the leg are ensured by a current reference level of 100 mA. PMID:10232813

  1. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz

    NASA Astrophysics Data System (ADS)

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-01

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg-1 with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings were confirmed

  2. Rating health and stability of engineering structures via classification indexes of InSAR Persistent Scatterers

    NASA Astrophysics Data System (ADS)

    Pratesi, Fabio; Tapete, Deodato; Terenzi, Gloria; Del Ventisette, Chiara; Moretti, Sandro

    2015-08-01

    We propose a novel set of indexes to classify the information content of Persistent Scatterers (PS) and rate the health of engineering structures at urban to local scale. PS are automatically sampled and grouped via 'control areas' coinciding with the building and its surrounding environment. Density over the 'control areas' and velocity of PS are converted respectively into: Completeness of Information Index (Ici) that reflects the PS coverage grade; and Conservation Criticality Indexes (Icc) which rate the health condition of the monument separately for the object and surrounding control areas. The deformation pattern over the structure is classified as isolated (i) or diffused (d) based on the Velocity Distribution Index (Ivd). Both Ici and Icc are rated from A to E classes using a colour-coded system that intentionally emulates an energy-efficiency scale, to encourage the exploitation of PS by stakeholders and end-users in the practise of engineering surveying. Workability and reliability of the classification indexes are demonstrated over the urban heritage of Florence, Italy, using well established ERS-1/2 (1992-2000) descending, ENVISAT (2003-2010) ascending and descending PS datasets. The indexes are designed in perspective of handling outputs from InSAR processing of higher-resolution time series.

  3. Toward Online Adaptive Hyperthermia Treatment Planning: Correlation Between Measured and Simulated Specific Absorption Rate Changes Caused by Phase Steering in Patients

    SciTech Connect

    Kok, H. Petra; Ciampa, Silvia; Kroon-Oldenhof, Rianne de; Steggerda-Carvalho, Eva J.; Stam, Gerard van; Zum Vörde Sive Vörding, Paul J.; Stalpers, Lukas J.A.; Geijsen, Elisabeth D.; Bardati, Fernando; Bel, Arjan; Crezee, Johannes

    2014-10-01

    Purpose: Hyperthermia is the clinical application of heat, in which tumor temperatures are raised to 40°C to 45°C. This proven radiation and chemosensitizer significantly improves clinical outcome for several tumor sites. Earlier studies of the use of pre-treatment planning for hyperthermia showed good qualitative but disappointing quantitative reliability. The purpose of this study was to investigate whether hyperthermia treatment planning (HTP) can be used more reliably for online adaptive treatment planning during locoregional hyperthermia treatments. Methods and Materials: This study included 78 treatment sessions for 15 patients with non-muscle-invasive bladder cancer. At the start of treatments, temperature rise measurements were performed with 3 different antenna settings optimized for each patient, from which the absorbed power (specific absorption rate [SAR]) was derived. HTP was performed based on a computed tomography (CT) scan in treatment position with the bladder catheter in situ. The SAR along the thermocouple tracks was extracted from the simulated SAR distributions. Correlations between measured and simulated (average) SAR values were determined. To evaluate phase steering, correlations between the changes in simulated and measured SAR values averaged over the thermocouple probe were determined for all 3 combinations of antenna settings. Results: For 42% of the individual treatment sessions, the correlation coefficient between measured and simulated SAR profiles was higher than 0.5, whereas 58% showed a weak correlation (R of <0.5). The overall correlation coefficient between measured and simulated average SAR was weak (R=0.31; P<.001). The measured and simulated changes in average SAR after adapting antenna settings correlated much better (R=0.70; P<.001). The ratio between the measured and simulated quotients of maximum and average SARs was 1.03 ± 0.26 (mean ± SD), indicating that HTP can also correctly predict the relative amplitude of

  4. Specific absorption rate variation in a brain phantom due to exposure by a 3G mobile phone: problems in dosimetry.

    PubMed

    Behari, J; Nirala, Jay Prakash

    2013-12-01

    A specific absorption rate (SAR) measurements system has been developed for compliance testing of personal mobile phone in a brain phantom material contained in a Perspex box. The volume of the box has been chosen corresponding to the volume of a small rat and illuminated by a 3G mobile phone frequency (1718.5 MHz), and the emitted radiation directed toward brain phantom .The induced fields in the phantom material are measured. Set up to lift the plane carrying the mobile phone is run by a pulley whose motion is controlled by a stepper motor. The platform is made to move at a pre-determined rate of 2 degrees per min limited up to 20 degrees. The measured data for induced fields in various locations are used to compute corresponding SAR values and inter comparison obtained. These data are also compared with those when the mobile phone is placed horizontally with respect to the position of the animal. The SAR data is also experimentally obtained by measuring a rise in temperature due to this mobile exposures and data compared with those obtained in the previous set. To seek a comparison with the safety criteria same set of measurements are performed in 10 g phantom material contained in a cubical box. These results are higher than those obtained with the knowledge of induced field measurements. It is concluded that SAR values are sensitive to the angular position of the moving platform and are well below the safety criteria prescribed for human exposure. The data are suggestive of having a fresh look to understand the mode of electromagnetic field -bio interaction. PMID:24579373

  5. Subsidence rate monitoring of Aghajari oil field based on Differential SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Moghaddam, N. Fouladi; Sahebi, M. R.; Matkan, A. A.; Roostaei, M.

    2013-06-01

    Land subsidence, due to natural or anthropogenic processes, causes significant costs in both economic and structural aspects. That part of subsidence observed most is the result of human activities, which relates to underground exploitation. Since the gradual surface deformation is a consequence of hydrocarbon reservoirs extraction, the process of displacement monitoring is amongst the petroleum industry priorities. Nowadays, Differential SAR Interferometry, in which satellite images are utilized for elevation change detection and analysis - in a millimetre scale, has proved to be a more real-time and cost-effective technology in contrast to the traditional surveying method. In this study, surface displacements in Aghajari oil field, i.e. one of the most industrious Iranian hydrocarbon sites, are being examined using radar observations. As in a number of interferograms, the production wells inspection reveals that surface deformation signals develop likely due to extraction in a period of several months. In other words, different subsidence or uplift rates and deformation styles occur locally depending on the geological conditions and excavation rates in place.

  6. Monitoring land subsidence rates with permanent scatterers SAR interferometry: a case study of Beijing, China

    NASA Astrophysics Data System (ADS)

    Fan, Jun; Li, Xiaojuan; Yu, Jie; Wang, Yanbing; Wan, Yanyan; An, Zhihui

    2015-12-01

    The ground subsidence phenomenon is more serious in Beijing, large-scale land subsidence seriously threats to urban planning and construction and the safety of residents. In order to study the subsidence condition, it is necessary to monitor land subsidence. Choosing 28 scenes Envisat ASAR images covering Beijing city from December 2003 to March 2009, permanent scatterer SAR interferometry (PSI) technique was applied to obtained time series land subsidence information. Then the trend characteristics and factors of subsidence were analyzed, comparing land subsidence result with the groundwater data and geological structure data. Comparison between the PSI-derived subsidence rates and leveling data obtained shows that the result of PSI is agreed with the leveling data. The results indicate that the PSI technique is capable of providing high-level accuracy subsidence information. The results show that:(1) The deformation rates derived PSI ranging from -45.80 to 4.36mm/a;(2) In the study area, the serious subsidence areas distribute in Chaoyang District, Shunyi District, Tongzhou District and Pinggu District;(3) The subsidence tends to become more and more concentrated in 6 years from 2003 to 2009.

  7. Accuracy improvement of the ice flow rate measurements on Antarctic ice sheet by DInSAR method

    NASA Astrophysics Data System (ADS)

    Shiramizu, Kaoru; Doi, Koichiro; Aoyama, Yuichi

    2015-04-01

    DInSAR (Differential Interferometric Synthetic Aperture Radar) is an effective tool to measure the flow rate of slow flowing ice streams on Antarctic ice sheet with high resolution. In the flow rate measurement by DInSAR method, we use Digital Elevation Model (DEM) at two times in the estimating process. At first, we use it to remove topographic fringes from InSAR images. And then, it is used to project obtained displacements along Line-Of-Sight (LOS) direction to the actual flow direction. ASTER-GDEM widely-used for InSAR prosessing of the data of polar region has a lot of errors especially in the inland ice sheet area. Thus the errors yield irregular flow rates and directions. Therefore, quality of DEM has a substantial influence on the ice flow rate measurement. In this study, we created a new DEM (resolution 10m; hereinafter referred to as PRISM-DEM) based on ALOS/PRISM images, and compared PRISM-DEM and ASTER-GDEM. The study area is around Skallen, 90km south from Syowa Station, in the southern part of Sôya Coast, East Antarctica. For making DInSAR images, we used ALOS/PALSAR data of 13 pairs (Path633, Row 571-572), observed during the period from November 23, 2007 through January 16, 2011. PRISM-DEM covering the PALSAR scene was created from nadir and backward view images of ALOS/PRISM (Observation date: 2009/1/18) by applying stereo processing with a digital mapping equipment, and then the automatically created a primary DEM was corrected manually to make a final DEM. The number of irregular values of actual ice flow rate was reduced by applying PRISM-DEM compared with that by applying ASTER-GDEM. Additionally, an averaged displacement of approximately 0.5cm was obtained by applying PRISM-DEM over outcrop area, where no crustal displacement considered to occur during the recurrence period of ALOS/PALSAR (46days), while an averaged displacement of approximately 1.65 cm was observed by applying ASTER-GDEM. Since displacements over outcrop area are considered

  8. Energy transmission transformer for a wireless capsule endoscope: analysis of specific absorption rate and current density in biological tissue.

    PubMed

    Shiba, Kenji; Nagato, Tomohiro; Tsuji, Toshio; Koshiji, Kohji

    2008-07-01

    This paper reports on the electromagnetic influences on the analysis of biological tissue surrounding a prototype energy transmission system for a wireless capsule endoscope. Specific absorption rate (SAR) and current density were analyzed by electromagnetic simulator in a model consisting of primary coil and a human trunk including the skin, fat, muscle, small intestine, backbone, and blood. First, electric and magnetic strength in the same conditions as the analytical model were measured and compared to the analytical values to confirm the validity of the analysis. Then, SAR and current density as a function of frequency and output power were analyzed. The validity of the analysis was confirmed by comparing the analytical values with the measured ones. The SAR was below the basic restrictions of the International Commission on Nonionizing Radiation Protection (ICNIRP). At the same time, the results for current density show that the influence on biological tissue was lowest in the 300-400 kHz range, indicating that it was possible to transmit energy safely up to 160 mW. In addition, we confirmed that the current density has decreased by reducing the primary coil's current. PMID:18595805

  9. Analysis of current density and specific absorption rate in biological tissue surrounding transcutaneous transformer for an artificial heart.

    PubMed

    Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

    2008-01-01

    This paper reports on the current density and specific absorption rate (SAR) analysis of biological tissue surrounding an air-core transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue is analyzed by the transmission line modeling method, and the current density and SAR as a function of frequency, output voltage, output power, and coil dimension are calculated. The biological tissue of the model has three layers including the skin, fat, and muscle. The results of simulation analysis show SARs to be very small at any given transmission conditions, about 2-14 mW/kg, compared to the basic restrictions of the International Commission on nonionizing radiation protection (ICNIRP; 2 W/kg), while the current density divided by the ICNIRP's basic restrictions gets smaller as the frequency rises and the output voltage falls. It is possible to transfer energy below the ICNIRP's basic restrictions when the frequency is over 250 kHz and the output voltage is under 24 V. Also, the parts of the biological tissue that maximized the current density differ by frequencies; in the low frequency is muscle and in the high frequency is skin. The boundary is in the vicinity of the frequency 600-1000 kHz. PMID:18232363

  10. Subcutaneous insulin infusion: change in basal infusion rate has no immediate effect on insulin absorption rate

    SciTech Connect

    Hildebrandt, P.; Birch, K.; Jensen, B.M.; Kuehl, C.

    1986-11-01

    Eight insulin-dependent diabetic patients were simultaneously given subcutaneous infusions (1.12 IU/h each) of /sup 125/I-labeled Actrapid insulin in each side of the abdominal wall. After 24 h of infusion, the size of the infused insulin depots was measured by external counting for 5 h. The basal infusion rate was then doubled in one side and halved in the other for the next 4 h. Finally, 1.12 IU/h of insulin was given in both sides of the abdominal wall for an additional 3 h. The changes in the size of the depots were measured, and the absorption rates for each hour were calculated. During the first 5 h of infusion, the depot size was almost constant (approximately 5 IU) with an absorption rate that equaled the infusion rate. Doubling the infusion rate led to a significant increase in depot size, but the absorption rate remained unchanged for the first 3 h, and only thereafter was a significant increase seen. When the infusion rate was reduced to the initial 1.12 IU/h, the absorption rate remained elevated during the next 3 h. Correspondingly, when the infusion rate was decreased, the depot size also decreased, but the absorption rate remained unchanged for the first 3 h. The results show that a change in the basal insulin infusion rate does not lead to any immediate change in the insulin absorption rate. This should be considered when planning an insulin-infusion program that includes alteration(s) in the basal-rate setting.

  11. Relationship between peak spatial-averaged specific absorption rate and peak temperature elevation in human head in frequency range of 1–30 GHz

    NASA Astrophysics Data System (ADS)

    Morimoto, Ryota; Laakso, Ilkka; De Santis, Valerio; Hirata, Akimasa

    2016-07-01

    This study investigates the relationship between the peak temperature elevation and the peak specific absorption rate (SAR) averaged over 10 g of tissue in human head models in the frequency range of 1–30 GHz. As a wave source, a half-wave dipole antenna resonant at the respective frequencies is located in the proximity of the pinna. The bioheat equation is used to evaluate the temperature elevation by employing the SAR, which is computed by electromagnetic analysis, as a heat source. The computed SAR is post-processed by calculating the peak spatial-averaged SAR with six averaging algorithms that consider different descriptions provided in international guidelines and standards, e.g. the number of tissues allowed in the averaging volume, different averaging shapes, and the consideration of the pinna. The computational results show that the SAR averaging algorithms excluding the pinna are essential when correlating the peak temperature elevation in the head excluding the pinna. In the averaging scheme considering an arbitrary shape, for better correlation, multiple tissues should be included in the averaging volume rather than a single tissue. For frequencies higher than 3–4 GHz, the correlation for peak temperature elevation in the head excluding the pinna is modest for the different algorithms. The 95th percentile value of the heating factor as well as the mean and median values derived here would be helpful for estimating the possible temperature elevation in the head.

  12. Specific absorption rate levels measured in a phantom head exposed to radio frequency transmissions from analog hand-held mobile phones

    SciTech Connect

    Anderson, V.; Joyner, K.H.

    1995-05-01

    Electric fields (E-fields) induced within a phantom head from exposure to three different advanced mobile phone system (AMPS) hand-held telephones were measured using an implantable E-Field probe. Measurements were taken in the eye nearest the phone and along a lateral scan through the brain from its center to the side nearest the phone. During measurement, the phones were positioned alongside the phantom head as in typical use and were configured to transmit at maximum power (600 mW nominal). The specific absorption rate (SAR) was calculated from the in situ E-field measurements, which varied significantly between phone models and antenna configuration. The SARs induced in the eye ranged from 0.007 to 0.21 W/kg. Metal-framed spectacles enhanced SAR levels in the eye by 9--29%. In the brain, maximum levels were recorded at the measurement point closest to the phone and ranged from 0.12 to 0.83 W/kg. These SARs are below peak spatial limits recommended in the US and Australian national standards and the IRPA guidelines for safe exposure to radio frequency (RF) electromagnetic fields. Furthermore, a detailed thermal analysis of the eye indicated only a 0.022 C maximum steady-state temperature rise in the eye from a uniform SAR loading of 0.21 W/kg. A more approximate thermal analysis in the brain also indicated only a small maximum temperature rise of 0.034 C for a local SAR loading of 0.83 W/kg.

  13. Correlation between nasal membrane permeability and nasal absorption rate.

    PubMed

    Zhang, Hefei; Lin, Chih-Wei; Donovan, Maureen D

    2013-03-01

    The objective of this study was to investigate the relationship between in vitro permeability (Papp) values obtained from isolated nasal tissues and the absorption rates (ka) of the same compounds following nasal administration in animals and humans. The Papp of a set of 11 drug compounds was measured using animal nasal explants and plasma time-concentration profiles for each of the same compounds following intravenous (IV) and intranasal (IN) administration were experimentally determined or obtained from literature reports. The plasma clearance was estimated from the IV plasma time-concentration profiles, and ka was determined from the IN plasma time-concentration profiles using a deconvolution approach. The level of correlation between Papp and ka was established using Pearson correlation analysis. A good correlation (r=0.77) representing a point-to-point relationship for each of the compounds was observed. This result indicates that the nasal absorption for many drug candidates can be estimated from a readily measured in vitro Papp value. PMID:23225081

  14. Characteristics of the SAR distributions in a head exposed to electromagnetic fields radiated by a hand-held portable radio

    SciTech Connect

    Watanabe, Soichi; Taki, Masao; Nojima, Toshio; Fujiwara, Osamu

    1996-10-01

    This paper presents characteristics of the specific absorption rate (SAR) distributions calculated by the finite-difference time-domain (FDTD) method using a heterogeneous and realistic head model and a realistic hand-held portable radio model. The difference between the SAR distributions produced by a 1/4-wavelength monopole antenna and those produced by a 1/2-wavelength dipole antenna is investigated. The dependence of the maximum local SAR on the distance d{sub a} between the auricle of the head and the antenna of the radio is evaluated. It is shown that the maximum local SAR decreases as the antenna length extends from 1/4 to 1/2 of the wavelength. The maximum local SAR`s in a head model with auricles are larger than those in one without auricles. The dependence of the SAR on the electrical inhomogeneity of the tissues in the head model is not significant with regard to the surface distribution and the maximum local SAR when the radio is near the head. It is also shown that the maximum local SAR is not strongly dependent on the position of the hand when the hand does not shade the antenna. Furthermore, the SAR`s experimentally measured in a homogeneous head phantom are compared with the calculated SAR`s.

  15. Multimodal Superparamagnetic Nanoparticles with Unusually Enhanced Specific Absorption Rate for Synergetic Cancer Therapeutics and Magnetic Resonance Imaging.

    PubMed

    Thorat, Nanasaheb D; Bohara, Raghvendra A; Malgras, Victor; Tofail, Syed A M; Ahamad, Tansir; Alshehri, Saad M; Wu, Kevin C-W; Yamauchi, Yusuke

    2016-06-15

    Superparamagnetic nanoparticles (SPMNPs) used for magnetic resonance imaging (MRI) and magnetic fluid hyperthermia (MFH) cancer therapy frequently face trade off between a high magnetization saturation and their good colloidal stability, high specific absorption rate (SAR), and most importantly biological compatibility. This necessitates the development of new nanomaterials, as MFH and MRI are considered to be one of the most promising combined noninvasive treatments. In the present study, we investigated polyethylene glycol (PEG) functionalized La1-xSrxMnO3 (LSMO) SPMNPs for efficient cancer hyperthermia therapy and MRI application. The superparamagnetic nanomaterial revealed excellent colloidal stability and biocompatibility. A high SAR of 390 W/g was observed due to higher colloidal stability leading to an increased Brownian and Neel's spin relaxation. Cell viability of PEG capped nanoparticles is up to 80% on different cell lines tested rigorously using different methods. PEG coating provided excellent hemocompatibility to human red blood cells as PEG functionalized SPMNPs reduced hemolysis efficiently compared to its uncoated counterpart. Magnetic fluid hyperthermia of SPMNPs resulted in cancer cell death up to 80%. Additionally, improved MRI characteristics were also observed for the PEG capped La1-xSrxMnO3 formulation in aqueous medium compared to the bare LSMO. Taken together, PEG capped SPMNPs can be useful for diagnosis, efficient magnetic fluid hyperthermia, and multimodal cancer treatment as the amphiphilicity of PEG can easily be utilized to encapsulate hydrophobic drugs. PMID:27197993

  16. The relationship between specific absorption rate and temperature elevation in anatomically based human body models for plane wave exposure from 30 MHz to 6 GHz.

    PubMed

    Hirata, Akimasa; Laakso, Ilkka; Oizumi, Takuya; Hanatani, Ryuto; Chan, Kwok Hung; Wiart, Joe

    2013-02-21

    According to the international safety guidelines/standard, the whole-body-averaged specific absorption rate (Poljak et al 2003 IEEE Trans. Electromagn. Compat. 45 141-5) and the peak spatial average SAR are used as metrics for human protection from whole-body and localized exposures, respectively. The IEEE standard (IEEE 2006 IEEE C95.1) indicates that the upper boundary frequency, over which the whole-body-averaged SAR is deemed to be the basic restriction, has been reduced from 6 to 3 GHz, because radio-wave energy is absorbed around the body surface when the frequency is increased. However, no quantitative discussion has been provided to support this description especially from the standpoint of temperature elevation. It is of interest to investigate the maximum temperature elevation in addition to the core temperature even for a whole-body exposure. In the present study, using anatomically based human models, we computed the SAR and the temperature elevation for a plane-wave exposure from 30 MHz to 6 GHz, taking into account the thermoregulatory response. As the primary result, we found that the ratio of the core temperature elevation to the whole-body-averaged SAR is almost frequency independent for frequencies below a few gigahertz; the ratio decreases above this frequency. At frequencies higher than a few gigahertz, core temperature elevation for the same whole-body averaged SAR becomes lower due to heat convection from the skin to air. This lower core temperature elevation is attributable to skin temperature elevation caused by the power absorption around the body surface. Then, core temperature elevation even for whole-body averaged SAR of 4 W kg(-1) with the duration of 1 h was at most 0.8 °C, which is smaller than a threshold considered in the safety guidelines/standard. Further, the peak 10 g averaged SAR is correlated with the maximum body temperature elevations without extremities and pinna over the frequencies considered. These findings

  17. Tenfold Disparity Between Decadal InSAR and Millennial Morphochronologic Slip-Rates on the Karakorum Fault

    NASA Astrophysics Data System (ADS)

    Chevalier, M.; Ryerson, F. J.; Tapponnier, P.; Finkel, R. C.; van der Woerd, J.; Li, H.; Liu, Q.

    2004-12-01

    The role of the Karakorum Fault in the kinematics of present-day deformation in Tibet is debated. Although it is the main dextral strike-slip fault north of the Himalayas, recent InSAR data are interpreted to suggest that it is barely active, moving at a rate of 1 ± 3 mm/yr. Surface exposure dating of moraines and terraces south of Bangong lake tell a different story, suggesting it slips ten times as fast. At one site on the west side of the Gar graben (32° 3' N-80° 1' E, 4365 m-4760 m), at the foot of the Aliyari Range, we sampled quartz-rich, rooted blocks on the lateral moraine crests of a large till complex. The moraines are offset right-laterally relative to the valley of the Manikala Daer Glacier. Twenty-seven samples were dated using cosmogenic 10Be. The offsets of 2 well-defined moraine crests (M1 and M2E), obtained from retro-deformation of 1 m-resolution IKONOS images, are 220 ± 10 m and 1520 ± 50 m, respectively. The 10Be exposure ages fall in distinct clusters: 21 ± 0.1 ka and 40 ± 3 ka on M1, and 140 ± 5.5 ka and 180 ± 14 ka on M2. The ages of maximum sample abundance correlate remarkably well with the ages of the coldest periods derived from proxy paleo-temperature records (SPECMAP), suggesting that the Manikala glacier crossed the fault to emplace moraines northeast of the range front only during the LGM and penultimate glacial maximum (late stage 6), and implying little erosion. Pairing the abandonment ages of the two moraines ( ˜ 21 and 140 ka) with their offsets yields concordant dextral slip-rates of 10.9 ± 0.6 and 10.5 ± 0.5 mm/yr. The resulting, average slip rate (10.7 ± 0.7 mm/yr) we derive for the last 150 ka is comparable to the geological rate obtained by Lacassin et al., [2004] (10 ± 3 mm/yr in the last 34 Ma) and to the GPS geodetic rate determined by Banerjee and Burgmann, [2002] (11 ± 4 mm/yr). It is almost 3 times greater than that measured in India by Brown et al., [2002] (4 ± 1 mm/yr) and three times smaller than that

  18. Specific absorption rate and temperature elevation in a subject exposed in the far-field of radio-frequency sources operating in the 10-900-MHz range.

    PubMed

    Bernardi, Paolo; Cavagnaro, Marta; Pisa, Stefano; Piuzzi, Emanuele

    2003-03-01

    The exposure of a subject in the far field of radiofrequency sources operating in the 10-900-MHz range has been studied. The electromagnetic field inside an anatomical heterogeneous model of the human body has been computed by using the finite-difference time-domain method; the corresponding temperature increase has been evaluated through an explicit finite-difference formulation of the bio-heat equation. The thermal model used, which takes into account the thermoregulatory system of the human body, has been validated through a comparison with experimental data. The results show that the peak specific absorption rate (SAR) as averaged over 10 g has about a 25-fold increase in the trunk and a 50-fold increase in the limbs with respect to the whole body averaged SAR (SARWB). The peak SAR as averaged over 1 g, instead, has a 30- to 60-fold increase in the trunk, and up to 135-fold increase in the ankles, with respect to SARWB. With reference to temperature increases, at the body resonance frequency of 40 MHz, for the ICNIRP incident power density maximum permissible value, a temperature increase of about 0.7 degrees C is obtained in the ankles muscle. The presence of the thermoregulatory system strongly limits temperature elevations, particularly in the body core. PMID:12669986

  19. Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.

    PubMed

    Sunohara, Tetsu; Hirata, Akimasa; Laakso, Ilkka; Onishi, Teruo

    2014-07-21

    This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium. The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and charging conditions are considered. The transfer frequency considered in this study is 140 kHz, which is within the range where the magneto-quasi-static approximation is valid. The SAR and in situ electric field in the chest and arm of the models are calculated by numerically solving the scalar potential finite difference equation. The electromagnetic modelling of the coils in the wireless power transfer system is verified by comparing the computed and measured magnetic field distributions. The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the in situ electric field are 72 nW kg(-1) and 91 mV m(-1) for a transmitted power of 1 W, Consequently, the maximum allowable transmitted powers satisfying the exposure limits of the SAR (2 W kg(-1)) and the in situ electric field (18.9 V m(-1)) are found to be 28 MW and 43 kW. The computational results show that the in situ electric field in the chest is the most restrictive factor when compliance with the wireless power transfer system is evaluated according to international guidelines. PMID:24936747

  20. Analysis on the effect of the distances and inclination angles between human head and mobile phone on SAR.

    PubMed

    Hossain, M I; Faruque, M R I; Islam, M T

    2015-11-01

    The aim of this paper is to investigate the effects of the distances between the human head and internal cellular device antenna on the specific absorption rate (SAR). This paper also analyzes the effects of inclination angles between user head and mobile terminal antenna on SAR values. The effects of the metal-glass casing of mobile phone on the SAR values were observed in the vicinity of the human head model. Moreover, the return losses were investigated in all cases to mark antenna performance. This analysis was performed by adopting finite-difference time-domain (FDTD) method on Computer Simulation Technology (CST) Microwave Studio. The results indicate that by increasing the distance between the user head and antenna, SAR values are decreased. But the increase in inclination angle does not reduce SAR values in all cases. Additionally, this investigation provides some useful indication for future design of low SAR mobile terminal antenna. PMID:25863147

  1. Determination of the magnetocrystalline anisotropy constant from the frequency dependence of the specific absorption rate in a frozen ferrofluid

    NASA Astrophysics Data System (ADS)

    Mosher, Nathaniel; Perkins-Harbin, Emily; Aho, Brandon; Wang, Lihua; Kumon, Ronald; Rablau, Corneliu; Vaishnava, Prem; Tackett, Ronald; Therapeutic Biomaterials Group Team

    2015-03-01

    Colloidal suspensions of superparamagnetic nanoparticles, known as ferrofluids, are promising candidates for the mediation of magnetic fluid hyperthermia (MFH). In such materials, the dissipation of heat occurs as a result of the relaxation of the particles in an applied ac magnetic field via the Brownian and Neel mechanisms. In order to isolate and study the role of the Neel mechanism in this process, the sample can be frozen, using liquid nitrogen, in order to suppress the Brownian relaxation. In this experiment, dextran-coated Fe3O4 nanoparticles synthesized via co-precipitation and characterized via transmission electron microscopy and dc magnetization are used as MFH mediators over the temperature range between -70 °C to -10 °C (Brownian-suppressed state). Heating the nanoparticles using ac magnetic field (amplitude ~300 Oe), the frequency dependence of the specific absorption rate (SAR) is calculated between 150 kHz and 350 kHz and used to determine the magnetocrystalline anisotropy of the sample. We would like to thank Fluxtrol, Inc. for their help with this project

  2. SAR measurement in MRI: an improved method

    NASA Astrophysics Data System (ADS)

    Romano, Rocco; Acernese, Fausto; Indovina, Pietro Luigi; Barone, Fabrizio

    2009-03-01

    During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2- 33). The phase transition method is a new method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. Furthermore, in this method, it is possible to show that all deposited SAR power can be considered acquired and measured.

  3. Impairment of jejunal absorption rate of carnosine by glycylglycine in man in vivo.

    PubMed Central

    Cook, G C

    1976-01-01

    Using a double-lumen tube jejunal perfusion system in vivo, the mutual effects of carnosine (beta-alanyl-L-histidine) and glycylglycine on their respective absorption rates have been studied in six Zambian African adults. Data on the effect of the constituent amino-acids of carnosine on glycylglycine absorption rate have similarly been obtained. The solutions infused in each subject contained (A) carnosine (50 mmol l.-1), (B) carnosine (50 mmol l.-1) and glycylglycine (50 mmol l.-1), (C) glycylglycine (50 mmol l.-1), and (D) glycylglycine (50 mmol l.-1), L-histidine (50 mmol l.-1) and beta-alanine (50 mmol l.-1). Glycylglycine produced a significant impairment in the mean rate of histidine absorption from carnosine (P less than 0-01). However, carnosine did not have a significant effect on the mean rate of glycine absorption from glycylglycine. Mean rate of histidine absorption from solution D was significantly higher than that from solution A (P less than 0-01). Mean rate of glycine absorption from glycylglycine was not significantly different during infusion of solutions B, C, and D. The results are consistent with the concept that carnosine on glycylglycine is probably because the affinity of mechanism; the lack of influence of carnosine on glycylglycine is probably because the affinity of carnosine for the dipeptide uptake mechanism is relatively low. A gross difference has been shown between mean absorption rate of histidine from free L-histidine (solution D) (25-8 mmol h-1) and when it is given in the form of carnosine in the presence of another dipeptide (solution B) (8-7 mmol h-1); that emphasizes the complexity of amino acid and peptide interaction during absorption, which must be important in nutrition. PMID:773786

  4. Creeping along the Ismetpasa section of the North Anatolian fault (Western Turkey): Rate and extent from InSAR [rapid communication

    NASA Astrophysics Data System (ADS)

    Cakir, Ziyadin; Akoglu, Ahmet M.; Belabbes, Samir; Ergintav, Semih; Meghraoui, Mustapha

    2005-09-01

    Creeping along the North Anatolian fault (NAF) at Ismetpasa (Turkey) was discovered some thirty years ago, about a decade after the first observations of the phenomenon along the San Andreas fault in California. However, little is known about its lateral extent and rate. In order to study its three dimensional nature and rupture characteristics, we use Synthetic Aperture Radar Interferometry (InSAR) and elastic dislocation models compared also with field observations. Interferograms with temporal baselines ranging between 1.25 and 5 years show that the creeping section starts at the western termination of the 1943 ( M = 7.6) earthquake rupture. It continues about 70-km to the west, overlapping with the eastern part of the 1944 ( M = 7.3) earthquake rupture. Offsets along strike indicate a maximum creep rate of 11 ± 3 mm/year near the mid point of the creeping section decreasing gradually towards the edges. Near Ismetpasa, InSAR data yield 8 ± 3 mm/year of creep rate, consistent with recent instrumental (triangulation and creepmeter) measurements. Modeling of the InSAR and GPS data suggests that the fault-creep occurs most probably at a shallow depth (0-7 km). Our analysis combined with previous studies suggests that creeping might have commenced following the 1944 earthquake, and thus may be a long-lasting, but transient slip episode.

  5. Correlation analysis of optical absorption cross section and rate coefficient measurements in reacting systems

    SciTech Connect

    Hessler, J.P.; Ogren, P.J.

    1992-08-31

    A technique was developed for determining relative importance and correlation between reactions making up a complex kinetic system. This technique was used to investigate measurements of optical absorption cross sections and the correlation between cross sections and measured rate coefficients. It is concluded that (1) species, initial conditions, and temporal regions may be identified where cross sections may be measured without interference from the kinetic behavior of the observed species and (2) experiments designed to measure rate coefficients will always be correlated with the absorption cross section of the observed species. This correlation may reduce the accuracy of rate coefficient measurements.

  6. Numerical analysis of specific absorption rate in the human head due to a 13.56 MHz RFID-based intra-ocular pressure measurement system.

    PubMed

    Hirtl, Rene; Schmid, Gernot

    2013-09-21

    A modern wireless intra-ocular pressure monitoring system, based on 13.56 MHz inductively coupled data transmission, was dosimetrically analyzed with respect to the specific absorption rate (SAR) induced inside the head and the eye due to the electromagnetic field exposure caused by the reader antenna of the transmission system. The analysis was based on numerical finite difference time domain computations using a high resolution anatomical eye model integrated in a modern commercially available anatomical model of a male head. Three different reader antenna configurations, a 7-turn elliptic (30 mm × 50 mm) antenna at 12 mm distance from the eye, a flexible circular antenna (60 mm diameter, 8 turns on 2 mm substrate) directly attached to the skin, and a circular 7-turn antenna (30 mm diameter at 12 mm distance to the eye) were analyzed, respectively. Possible influences of the eye-lid status (closed or opened) and the transponder antenna contained in a contact lens directly attached to the eye were taken into account. The results clearly demonstrated that for typical reader antenna currents required for proper data transmission, the SAR values remain far below the limits for localized exposure of the head, as defined by the International Commission for Non-Ionizing Radiation Protection. Particularly the induced SAR inside the eye was found to be substantially (orders of magnitudes for typical reader antenna currents in the order of 1 A turn) below values which have been reported to be critical with respect to thermally induced adverse health effects in eye tissues. PMID:24002053

  7. Subpicosecond IR transient absorption spectroscopy: measurement of internal conversion rates in DABCO vapor

    NASA Astrophysics Data System (ADS)

    Glownia, J. H.; Misewich, J.; Sorokin, P. P.

    1987-09-01

    An apparatus combining subpicosecond 248.5 nm pump pulses with a time-resolved subpicosecond broadband infrared absorption spectroscopy probe has been utilized to measure an internal conversion rate in 1,4-diazabicyclo[2.2.2]octane vapor. A subpicosecond (⪅ 500 fs) internal conversion rate has been determined.

  8. Theory of absorption rate of carriers in fused silica under intense laser irradiation

    SciTech Connect

    Deng, Hongxiang; Xiang, Xia; Zheng, WG; Yuan, XD; Wu, SY; Jiang, XD; Gao, Fei; Zu, Xiaotao T.; Sun, Kai

    2010-11-15

    A quantum non-perturbation theory for phonon-assisted photon absorption of conduction band electron in intense laser was developed. By carrying out the calculation in fused silica at wavelengths from ultraviolet to infrared in terawatt intensity laser, we show that the Non-perturbation approach can make a uniform description of energy absorption rate at both short wavelengths and long wavelengths on TW / cm2 intensity laser.

  9. Determination of creep rate and extent at Ismetpasa section of the North Anatolian Fault using Persistent Scatterer InSAR and GPS

    NASA Astrophysics Data System (ADS)

    Cetin, E.; Cakir, Z.; Dogan, U.; Akoglu, A. M.; Ozener, H.; Ergintav, S.; Meghraoui, M.

    2012-12-01

    Although fault creep was discovered over half a century ago along the Ismetpasa section of the North Anatolian Fault, its spatiotemporal nature is still poorly known due to lack of geodetic and seismological studies along the fault. Despite the difficulties arising from atmospheric artifacts and low coherency, classical long-term InSAR analysis of ERS (C-band) data between 1992 and 2001 suggested an average creep rate of 9±3 mm along a fault segment of ~70 km long (Cakir et al., 2005). Even though these estimations were obtained from a limited number of available images, these results have been supported by a recent study of stacked PALSAR (L-band) interferograms spanning the period between 2007 and 2010 (Fialko et al., 2011). In this study, we use the Persistent Scatterer InSAR technique to better constrain spatiotemporal characteristics of the surface creep. We analyzed 55 Envisat ASAR images on 2 descending tracks (479 and 207) between 2003 and 2010 and calculated InSAR time series. The PS-InSAR results show clearly the gradual transition between the creeping and locked sections of the NAF west of Ismetpasa. On the contrary, its eastern boundary is crudely determined near 33.4E since the signal is disturbed by the postseismic deformation of the Orta earthquake (June 6, 2000, Mw=6.0). The extent of the creeping section therefore appears to be approximately 81.5 km. The creep rate is also robustly constrained and found to be in the range of 10±2 mm/yr near to Ismetpasa, consistent with the GPS measurements from a small-aperture geodetic network near Ismetpasa and recently reported PALSAR measurements (Fialko et al., 2011). Furthermore, elastic dislocation modeling suggests shallow creeping depth (< 5 km).

  10. Effect of SAR on human head modeling inside cylindrical enclosures.

    PubMed

    Mary, T Anita Jones; Ravichandran, C S

    2013-09-01

    This study intends to discuss enclosed a realistic approach to determine and analyze the effects of radio frequency on human exposure inside a cylindrical enclosure. A scenario in which a mobile phone with inverted-F antenna (IFA) operating in the Global System for Mobile Communication (GSM) band (900 MHz) is used inside a cylindrical enclosure. Metallic enclosures are known to have resonance and reflection effects, thereby increasing electric field strength and hence resulting in a change of the human exposure to electromagnetic absorptions. So, this study examines and compares the levels of absorption in terms of specific absorption rate (SAR) values under various conditions. In this study, a human phantom with dielectric properties is designed and its interaction is studied with IFA inside fully enclosed cylindrical enclosures. The results show that SAR values are increased inside cylindrical enclosures compared with those in free space. The method of computation uses method of moments. Simulations are done in FEKO software. PMID:23323517

  11. Effect of a hands-free wire on specific absorption rate for a waist-mounted 1.8 GHz cellular telephone handset

    NASA Astrophysics Data System (ADS)

    Troulis, S. E.; Scanlon, W. G.; Evans, N. E.

    2003-06-01

    A common feature of cellular telephony is the use of a 'hands-free' audio extension lead connected to a waist-worn handset. Interaction between the transmitting antenna, the wire and the user's body can occur, with detrimental effects including polar pattern degradation, reduced efficiency and localized increases in specific absorption rate (SAR). Using a realistic full-body model of an adult male, finite difference time domain analysis was employed to investigate the coupling between a hip-mounted 1.8 GHz handset fitted with a monopole antenna and a 1 m long wire representing a hands-free wire. Conduction current densities were computed for three identifiable coupling modes: magnetic-only, conductive-only and combined conductive-and-magnetic. Magnetic-only coupling was dominant. Without the lead, placing the handset at waist height led to a 42.8% increase in the total energy deposited in the body, compared to use at the head. Introducing the lead further increased the body loss, with a reduction in system radiation efficiency from 52% to 43.7%. Without the hands-free lead, the peak 1 g and 10 g SARs were 0.450 W kg-1 and 0.265 W kg-1, respectively, for 125 mW transmit power. With the hands-free lead connected, these values increased to 1.14 W kg-1 and 0.430 W kg-1, respectively.

  12. Effect of a hands-free wire on specific absorption rate for a waist-mounted 1.8 GHz cellular telephone handset.

    PubMed

    Troulis, S E; Scanlon, W G; Evans, N E

    2003-06-21

    A common feature of cellular telephony is the use of a 'hands-free' audio extension lead connected to a waist-worn handset. Interaction between the transmitting antenna, the wire and the user's body can occur, with detrimental effects including polar pattern degradation, reduced efficiency and localized increases in specific absorption rate (SAR). Using a realistic full-body model of an adult male, finite difference time domain analysis was employed to investigate the coupling between a hip-mounted 1.8 GHz handset fitted with a monopole antenna and a 1 m long wire representing a hands-free wire. Conduction current densities were computed for three identifiable coupling modes: magnetic-only, conductive-only and combined conductive-and-magnetic. Magnetic-only coupling was dominant. Without the lead, placing the handset at waist height led to a 42.8% increase in the total energy deposited in the body, compared to use at the head. Introducing the lead further increased the body loss, with a reduction in system radiation efficiency from 52% to 43.7%. Without the hands-free lead, the peak 1 g and 10 g SARs were 0.450 W kg(-1) and 0.265 W kg(-1), respectively, for 125 mW transmit power. With the hands-free lead connected, these values increased to 1.14 W kg(-1) and 0.430 W kg(-1), respectively. PMID:12870576

  13. Uncertainty of GHz-band Whole-body Average SARs in Infants based on their Kaup Indices

    NASA Astrophysics Data System (ADS)

    Miwa, Hironobu; Hirata, Akimasa; Fujiwara, Osamu; Nagaoka, Tomoaki; Watanabe, Soichi

    We previously showed that a strong correlation exists between the absorption cross section and the body surface area of a human for 0.3-2GHz far field exposure, and proposed a formula for estimating whole-body-average specific absorption rates (WBA-SARs) in terms of height and weight. In this study, to evaluate variability in the WBA-SARs in infants based on their physique, we derived a new formula including Kaup indices of infants, which are being used to check their growth, and thereby estimated the WBA-SARs in infants with respect to their age from 0 month to three years. As a result, we found that under the same height/weight, the smaller the Kaup indices are, the larger the WBA-SARs become, and that the variability in the WBA-SARs is around 15% at the same age. To validate these findings, using the FDTD method, we simulated the GHz-band WBA-SARs in numerical human models corresponding to infants with age of 0, 1, 3, 6 and 9 months, which were obtained by scaling down the anatomically based Japanese three-year child model developed by NICT (National Institute of Information and Communications Technology). Results show that the FDTD-simulated WBA-SARs are smaller by 20% compared to those estimated for infants having the median height and the Kaup index of 0.5 percentiles, which provide conservative WBA-SARs.

  14. 3D finite element simulation of effects of deflection rate on energy absorption for TRIP steel

    NASA Astrophysics Data System (ADS)

    Hayashi, Asuka; Pham, Hang; Iwamoto, Takeshi

    2015-09-01

    Recently, with the requirement of lighter weight and more safety for a design of automobile, energy absorption capability of structural materials has become important. TRIP (Transformation-induced Plasticity) steel is expected to apply to safety members because of excellent energy absorption capability and ductility. Past studies proved that such excellent characteristics in TRIP steel are dominated by strain-induced martensitic transformation (SIMT) during plastic deformation. Because SIMT strongly depends on deformation rate and temperature, an investigation of the effects of deformation rate and temperature on energy absorption in TRIP is essential. Although energy absorption capability of material can be estimated by J-integral experimentally by using pre-cracked specimen, it is difficult to determine volume fraction of martensite and temperature rise during the crack extension. In addition, their effects on J-integral, especially at high deformation rate in experiment might be quite hard. Thus, a computational prediction needs to be performed. In this study, bending deformation behavior of pre-cracked specimen until the onset point of crack extension are predicted by 3D finite element simulation based on the transformation kinetics model proposed by Iwamoto et al. (1998). It is challenged to take effects of temperature, volume fraction of martensite and deformation rate into account. Then, the mechanism for higher energy absorption characteristic will be discussed.

  15. Evaluation of different indirect measures of rate of drug absorption in comparative pharmacokinetic studies.

    PubMed

    Lacey, L F; Keene, O N; Duquesnoy, C; Bye, A

    1994-02-01

    As indirect measures of rate of drug absorption (metrics), maximum plasma concentration (Cmax) is confounded by extent of drug absorption and the time to reach Cmax (tmax) is a discrete variable, dependent on blood sampling frequency. Building on the work of Endrenyi et al., we have compared different metrics, including Cmax/area under the curve of concentration versus time from time zero to infinity (AUC infinity), partial AUC from zero to tmax (AUCp), and Cmax.tmax with simulated experiments. Importantly, the performance of these metrics was assessed with the results of actual pharmacokinetic studies involving Glaxo drugs. The results of the simulated and real experiments were consistent and produced the following unambiguous findings: (1) Cmax/AUC infinity is a more powerful metric than Cmax in establishing bioequivalence when the formulations are truly bioequivalent; (2) Cmax/AUC infinity is more sensitive than Cmax at detecting differences in rate of absorption when they exist; and (3) the treatment ratios for AUCp, AUCp/AUC infinity, and Cmax.tmax are very imprecisely estimated and are of no practical value as measures of rate of absorption. Of the metrics examined, Cmax/AUC infinity is the most sensitive and powerful indirect measure of rate of drug absorption in comparative pharmacokinetic studies involving immediate-release dosage forms and should be used instead of Cmax in bioequivalence testing. PMID:8169791

  16. Energy absorption at high strain rate of glass fiber reinforced mortars

    NASA Astrophysics Data System (ADS)

    Fenu, Luigi; Forni, Daniele; Cadoni, Ezio

    2015-09-01

    In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF) was finally evaluated.

  17. Metamaterial-Embedded Low SAR PIFA for Cellular Phone.

    PubMed

    Faruque, M R I; Hossain, M I; Misran, N; Singh, M; Islam, M T

    2015-01-01

    A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances. PMID:26599584

  18. Metamaterial-Embedded Low SAR PIFA for Cellular Phone

    PubMed Central

    Faruque, M. R. I.; Hossain, M. I.; Misran, N.; Singh, M.; Islam, M. T.

    2015-01-01

    A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances. PMID:26599584

  19. Assessment of induced SAR in children exposed to electromagnetic plane waves between 10 MHz and 5.6 GHz.

    PubMed

    Bakker, J F; Paulides, M M; Christ, A; Kuster, N; van Rhoon, G C

    2010-06-01

    To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels from the basic restrictions on the induced whole-body-averaged specific absorption rate (SAR(wb)) and the peak 10 g spatial-averaged SAR (SAR(10g)). The objective of this study is to assess if the SAR in children remains below the basic restrictions upon exposure at the reference levels. Finite difference time domain (FDTD) modeling was used to calculate the SAR in six children and two adults when exposed to all 12 orthogonal plane wave configurations. A sensitivity study showed an expanded uncertainty of 53% (SAR(wb)) and 58% (SAR(10g)) due to variations in simulation settings and tissue properties. In this study, we found that the basic restriction on the SAR(wb) is occasionally exceeded for children, up to a maximum of 45% in small children. The maximum SAR(10g) values, usually found at body protrusions, remain under the limit for all scenarios studied. Our results are in good agreement with the literature, suggesting that the recommended ICNIRP reference levels may need fine tuning. PMID:20463374

  20. Estimation of the whole-body averaged SAR of grounded human models for plane wave exposure at respective resonance frequencies.

    PubMed

    Hirata, Akimasa; Yanase, Kazuya; Laakso, Ilkka; Chan, Kwok Hung; Fujiwara, Osamu; Nagaoka, Tomoaki; Watanabe, Soichi; Conil, Emmanuelle; Wiart, Joe

    2012-12-21

    According to the international guidelines, the whole-body averaged specific absorption rate (WBA-SAR) is used as a metric of basic restriction for radio-frequency whole-body exposure. It is well known that the WBA-SAR largely depends on the frequency of the incident wave for a given incident power density. The frequency at which the WBA-SAR becomes maximal is called the 'resonance frequency'. Our previous study proposed a scheme for estimating the WBA-SAR at this resonance frequency based on an analogy between the power absorption characteristic of human models in free space and that of a dipole antenna. However, a scheme for estimating the WBA-SAR in a grounded human has not been discussed sufficiently, even though the WBA-SAR in a grounded human is larger than that in an ungrounded human. In this study, with the use of the finite-difference time-domain method, the grounded condition is confirmed to be the worst-case exposure for human body models in a standing posture. Then, WBA-SARs in grounded human models are calculated at their respective resonant frequencies. A formula for estimating the WBA-SAR of a human standing on the ground is proposed based on an analogy with a quarter-wavelength monopole antenna. First, homogenized human body models are shown to provide the conservative WBA-SAR as compared with anatomically based models. Based on the formula proposed here, the WBA-SARs in grounded human models are approximately 10% larger than those in free space. The variability of the WBA-SAR was shown to be ±30% even for humans of the same age, which is caused by the body shape. PMID:23202273

  1. A review of lung-to-blood absorption rates for radon progeny.

    PubMed

    Marsh, J W; Bailey, M R

    2013-12-01

    The International Commission on Radiological Protection (ICRP) Publication 66 Human Respiratory Tract Model (HRTM) treats clearance of materials from the respiratory tract as a competitive process between absorption into blood and particle transport to the alimentary tract and lymphatics. The ICRP recommended default absorption rates for lead and polonium (Type M) in ICRP Publication 71 but stated that the values were not appropriate for short-lived radon progeny. This paper reviews and evaluates published data from volunteer and laboratory animal experiments to estimate the HRTM absorption parameter values for short-lived radon progeny. Animal studies showed that lead ions have two phases of absorption: ∼10 % absorbed with a half-time of ∼15 min, the rest with a half-time of ∼10 h. The studies also indicated that some of the lead ions were bound to respiratory tract components. Bound fractions, f(b), for lead were estimated from volunteer and animal studies and ranged from 0.2 to 0.8. Based on the evaluations of published data, the following HRTM absorption parameter values were derived for lead as a decay product of radon: f(r) = 0.1, s(r) = 100 d(-1), s(s) = 1.7 d(-1), f(b) = 0.5 and s(b) = 1.7 d(-1). Effective doses calculated assuming these absorption parameter values instead of a single absorption half-time of 10 h with no binding (as has generally been assumed) are only a few per cent higher. However, as there is some conflicting evidence on the absorption kinetics for radon progeny, dose calculations have been carried out for different sets of absorption parameter values derived from different studies. The results of these calculations are discussed. PMID:23887272

  2. SARS Basics

    MedlinePlus

    ... waiting room or office. Top of Page CDC’s response to SARS during the 2003 outbreak CDC worked ... Center to provide round-the-clock coordination and response. Committed more than 800 medical experts and support ...

  3. Updated Long Term Fault Slip Rates and Seismic Hazard in the Central Alborz, Iran: New Constraints From InSAR and GPS

    NASA Astrophysics Data System (ADS)

    Weston, J. M.; Shirzaei, M.

    2015-12-01

    The Alborz mountain range, located south of the Caspian Sea, accommodates 30% of the 25 mm/yr convergence between Arabia and Eurasia. The resulting shortening and left lateral motion is distributed over several active fault zones within the Central Alborz. Despite earlier efforts using only GPS data, little is known about the long term rate of vertical deformation and aseismic slip. Several historical earthquakes have affected this region, some of the largest of these events occurred on the Mosha fault which is close to the capital city, Tehran, which has a population of over eight million. Thus, constraining the interseismic slip rates in this region is particularly important. In this study we complement existing horizontal velocities from a regional GPS network, with line of sight velocities from interferometric synthetic aperture radar (InSAR), to provide additional constraints on the vertical deformation and enhance the spatial coverage. Assuming a seismogenic depth of 30 km, based on microseismicity data, we solve for the geometry and long term slip rates on four major fault strands in this region. We obtain a long term slip rate of ~ 3 mm/yr for the Mosha and North Alborz faults, and ~ 10 mm/yr for the Khazar fault and Parchin faults. These rates and fault geometries are in agreement with earlier works, and fit the GPS data well. However, close to the fault traces there are large residuals in the InSAR data, suggesting that there is shallow creep (< 30 km). Therefore, we carry out a subsequent inversion using only the residual InSAR displacements to solve for the distribution of creep within the seismogenic zones on these faults. We find that the Mosha and North Alborz faults remain locked between 0 - 30 km depth, whilst the Parchin and Khazar faults are creeping. This new observation of fault creep has direct implications for the seismic hazard in the region. On the Mosha fault we estimate a slip deficit equivalent to a Mw 7.0 event. The combination of InSAR

  4. CRUCIAL: Cryosat-2 Success over Inland Water and Land: SAR and SARin Full Bit Rate Altimetric Heights and Validation

    NASA Astrophysics Data System (ADS)

    Moore, Philip; Birkinshaw, Stephen; Restano, Marco; Ambrozio, Americo; Benveniste, Jerome

    2016-04-01

    CRUCIAL is an ESA/STSE funded project investigating innovative land and inland water applications from Cryosat-2 with a forward-look component to the future Sentinel-3 and Jason-CS/Sentinel-6 missions. The high along-track sampling and resolution of Cryosat-2 altimeter in SAR and SARin modes offer the opportunity to recover high frequency signals over inland waters. This paper will present the theoretical approach to analysis of the FBR L1A Doppler beams to form a product using ground cell gridding, beam steering and beam stacking from which inland water heights are derivable from the retracked Cryosat-2 altimetric waveforms. Details of the processing strategy will include a comparison of waveforms and heights from the burst echoes (~80 m along-track) and from multi-look waveforms (~320 m along-track). SAR and SARin FBR data are available for the Amazon, Brahmaputra and Mekong. The Mekong and Amazon FBR SAR data has been processed for 2011-2015 and results will be compared against stage data from the nearest gauge. Similarly, heights from Tonle Sap will be compared against Jason-2 data from the United States Department of Agriculture web site. A strategy to select the number of multi-looks over rivers will also be presented. Results of FBR SARin processing will be presented including comparison of heights from the two antennae and the extraction of slope of the ground surface.

  5. Effects of Receive-Only Inserts on SAR, B1+ Field and Tx Coil Performance

    PubMed Central

    Krishnamurthy, Narayanan; Zhao, Tiejun; Ibrahim, Tamer S

    2013-01-01

    Purpose To evaluate the effect of different cylindrical and close conforming receive only array designs on spin excitation and specific absorption rate (SAR) of a 7 Tesla transmit only head coil. Materials and Methods We developed FDTD models of different receive only array geometries. Cylindrical and close fitting helmet arrays with varying copper trace widths; a TEM Tx coil model and two head models were used in numerical simulations. Tx coil coupling was experimentally measured and validated with FDTD modeling. Results Changing copper trace width of loops in array models caused subtle changes in RF absorption (<5%). Changes in SAR distribution were observed in the head models with Rx-only inserts. Peak SAR increased (−1 to +15%) in different tissues for a mean B1+ in the brain of 2 μT. Total absorption in the head models for 1 Watt forward power increased (5 to 21%) in the heads with Rx-only inserts. Changes in RF absorption with different Rx-inserts indicate a change in RF radiation of the Tx coil even when changes in B1+ and coupling between ports of Tx coil were minimal. Conclusion Changes in local/global SAR and subtle changes in B1+ field distributions were observed with the presence of Rx-only inserts. Thus, incorporation of the receive-only array effects are needed when evaluating SAR and designing RF transmit pulse waveform parameters for shimming and/or Tx-SENSE for 7 T MRI. PMID:23913474

  6. Differing rates of cholesterol absorption among inbred mouse strains yield differing levels of HDL-cholesterol.

    PubMed

    Sontag, Timothy J; Chellan, Bijoy; Getz, Godfrey S; Reardon, Catherine A

    2013-09-01

    Inbred strains of mice with differing susceptibilities to atherosclerosis possess widely varying plasma HDL levels. Cholesterol absorption and lipoprotein formation were compared between atherosclerosis-susceptible, low-HDL C57BL6/J mice and atherosclerosis-resistant, high-HDL FVBN/J mice. [(3)H]cholesterol and triglyceride appeared in the plasma of FVB mice gavaged with cholesterol in olive oil at a much higher rate than in C57 mice. The plasma cholesterol was found almost entirely as HDL-cholesterol in both strains. Inhibition of lipoprotein catabolism with Tyloxapol revealed that the difference in the rate of [(3)H]cholesterol appearance in the plasma was due entirely to a greater rate of chylomicron secretion from the intestine of the FVB mice. Lipid absorption into the 2nd quarter of the small intestine is greater in the FVB mice and indicates that this region may contain the factors that give rise to the differences in absorption observed between the two mouse strains. Additionally, ad libitum feeding prior to cholesterol gavage accentuates the absorption rate differences compared with fasting. The resultant remodeling of the increased levels of chylomicron in the plasma may contribute to increased plasma HDL. Intestinal gene expression analysis reveals several genes that may play a role in these differences, including microsomal triglyceride transfer protein and ABCG8. PMID:23812556

  7. Mechanism and rate of glucose absorption differ between an Australian honeyeater (Meliphagidae) and a lorikeet (Loriidae).

    PubMed

    Napier, Kathryn R; McWhorter, Todd J; Fleming, Patricia A

    2008-11-01

    Efficient mechanisms of glucose absorption are necessary for volant animals as a means of reducing mass during flight: they speed up gut transit time and require smaller volume and mass of gut tissue. One mechanism that may be important is absorption via paracellular (non-mediated) pathways. This may be particularly true for nectarivorous species which encounter large quantities of sugar in their natural diet. We investigated the extent of mediated and non-mediated glucose absorption in red wattlebirds Anthochaera carunculata (Meliphagidae) and rainbow lorikeets Trichoglossus haematodus (Loriidae) to test the hypothesis that paracellular uptake accounts for a significant proportion of total glucose uptake in these species. We found that routes of glucose absorption are highly dynamic in both species. In lorikeets, absorption of L-glucose (non-mediated uptake) is slower than that of D-glucose (mediated and non-mediated uptake), with as little as 10% of total glucose absorbed by the paracellular pathway initially (contrasting previous indirect estimates of approximately 80%). Over time, however, more glucose may be absorbed via the paracellular route. Glucose absorption by both mediated and non-mediated mechanisms in wattlebirds occurred at a faster rate than in lorikeets, and wattlebirds also rely substantially on paracellular uptake. In wattlebirds, we recorded higher bioavailability of L-glucose (96+/-3%) compared with D-glucose (57+/-2%), suggesting problems with the in vivo use of radiolabeled d-glucose. Further trials with 3-O-methyl-D-glucose revealed high bioavailability in wattlebirds (90+/-5%). This non-metabolisable glucose analogue remains the probe of choice for measuring uptake rates in vivo, especially in birds in which absorption and metabolism occur extremely rapidly. PMID:18978218

  8. Increased absorption rate of diclofenac from fast acting formulations containing its potassium salt.

    PubMed

    Reiner, V; Reiner, A; Reiner, G; Conti, M

    2001-11-01

    Diclofenac (CAS 15307-86-5) is a non-steroidal anti-inflammatory drug largely used, mainly to relief pain of various origin. Diclofenac is present on the market as free acid, as sodium salt (CAS 15307-79-6) and as potassium salt (CAS 15307-81-0). The last salification form has shown a prompter absorption rate and a faster onset of analgesic activity than the acid form and sodium salt. This paper extensively reviews three trials carried out on healthy volunteers, where potassium salt of diclofenac present in three fast-acting formulations, namely sachets (Trial 1), tablets (Trial 2) and oral drops (Trial 3), were compared to reference tablet formulations from the market. A very fast absorption rate was encountered with the three test formulations, with the peak reached in one case 5 min and in most cases within 10-15 min after dosing. The quick absorption rate of test formulations was attributed to the special combination of the salt of diclofenac with a dynamic buffering agent, namely bicarbonate, present in the test formulations and covered by an international patent. The prompt absorption of diclofenac from the new fast-acting formulations was accompanied by the presence of only one peak, whereas the reference formulations produced in most cases two peaks, as widely described in literature. This finding suggested the hypothesis that the absorption of test formulations should occur in a shorter tract of the gut. The faster absorption of diclofenac from the three fast-acting formulations is expected to produce a faster onset of analgesic action, which highlights these new formulations as particularly indicated to relief pain of any origin. PMID:11765589

  9. Effects of frequency, irradiation geometry and polarisation on computation of SAR in human brain.

    PubMed

    Zhou, Hongmei; Su, Zhentao; Ning, Jing; Wang, Changzhen; Xie, Xiangdong; Qu, Decheng; Wu, Ke; Zhang, Xiaomin; Pan, Jie; Yang, Guoshan

    2014-12-01

    The power absorbed by the human brain has possible implications in the study of the central nervous system-related biological effects of electromagnetic fields. In order to determine the specific absorption rate (SAR) of radio frequency (RF) waves in the human brain, and to investigate the effects of geometry and polarisation on SAR value, the finite-difference time-domain method was applied for the SAR computation. An anatomically realistic model scaled to a height of 1.70 m and a mass of 63 kg was selected, which included 14 million voxels segmented into 39 tissue types. The results suggested that high SAR values were found in the brain, i.e. ∼250 MHz for vertical polarisation and 900-1200 MHz both for vertical and horizontal polarisation, which may be the result of head resonance at these frequencies. PMID:24399107

  10. SAR Computation inside Fetus by RF Coil during MR Imaging Employing Realistic Numerical Pregnant Woman Model

    NASA Astrophysics Data System (ADS)

    Kikuchi, Satoru; Saito, Kazuyuki; Takahashi, Masaharu; Ito, Koichi; Ikehira, Hiroo

    This paper presents the computational electromagnetic dosimetry inside an anatomically based pregnant woman models exposed to electromagnetic wave during magnetic resonance imaging. The two types of pregnant woman models corresponding to early gestation and 26 weeks gestation were used for this study. The specific absorption rate (SAR) in and around a fetus were calculated by radiated electromagnetic wave from highpass and lowpass birdcage coil. Numerical calculation results showed that high SAR region is observed at the body in the vicinity of gaps of the coil, and is related to concentrated electric field in the gaps of human body such as armpit and thigh. Moreover, it has confirmed that the SAR in the fetus is less than International Electrotechnical Commission limit of 10W/kg, when whole-body average SARs are 2W/kg and 4W/kg, which are the normal operating mode and first level controlled operating mode, respectively.

  11. A new method for SAR measurement in MRI

    NASA Astrophysics Data System (ADS)

    Romano, Rocco; Acernese, Fausto; Indovina, Pietro Luigi; Barone, Fabrizio

    2008-03-01

    During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2 - 33). The phase transition method is a new method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement.

  12. Measurement of erosion rate by absorption spectroscopy in a Hall thruster

    SciTech Connect

    Yamamoto, Naoji; Yokota, Shigeru; Matsui, Makoto; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2005-08-15

    The erosion rate of a Hall thruster was estimated with the objective of building a real-time erosion rate monitoring system using a 1 kW class anode layer type Hall thruster. This system aids the understanding of the tradeoff between lifetime and performance. To estimate the flux of the sputtered wall material, the number density of the sputtered iron was measured by laser absorption spectroscopy using an absorption line from ground atomic iron at 371.9935 nm. An ultravioletAl{sub x}In{sub y}Ga{sub (1-x-y)}N diode laser was used as the probe. The estimated number density of iron was 1.1x10{sup 16} m{sup -3}, which is reasonable when compared with that measured by duration erosion tests. The relation between estimated erosion rate and magnetic flux density also agreed with that measured by duration erosion tests.

  13. Rate- and Extent-Limiting Factors of Oral Drug Absorption: Theory and Applications.

    PubMed

    Sugano, Kiyohiko; Terada, Katsuhide

    2015-09-01

    The oral absorption of drugs has been represented by various concepts such as the absorption potential, the maximum absorbable dose, the biopharmaceutics classification system, and in vitro-in vivo correlation. The aim of this article is to provide an overview of the theoretical relationships between these concepts. It shows how a simple analytical solution for the fraction of a dose absorbed (Fa equation) can offer a theoretical base to tie together the various concepts, and discusses how this solution relates to the rate-limiting cases of oral drug absorption. The article introduces the Fa classification system as a framework in which all the above concepts were included, and discusses its applications for food effect prediction, active pharmaceutical ingredient form selection, formulation design, and biowaiver strategy. PMID:25712830

  14. Fine resolution calculations of SAR in the human body for frequencies up to 3 GHz.

    PubMed

    Dimbylow, P J

    2002-08-21

    Finite-difference time-domain (FDTD) calculations of whole-body averaged specific energy absorption rate (SAR) have been performed from 100 MHz to 3 GHz at the basic 2 mm resolution of the voxel (volume pixel) model NORMAN without any rescaling to larger cell sizes. The reduction in the voxel size from previous work allows SAR to be calculated at higher frequencies. Additionally, the calculations have been extended down to 10 MHz, covering the whole-body resonance regions at a resolution of 4 mm. As well as for the adult phantom, SAR values are calculated for scaled versions representing 10-, 5- and 1-year-old children for both grounded and isolated conditions. External electric field levels are derived from limits of whole-body averaged SAR and localized SAR in the ankle, and compared with NRPB investigation levels and ICNIRP reference levels. The ICNIRP field reference levels alone would not provide a conservative estimate of the localized SAR exposure in the leg for grounded conditions. It would be necessary to invoke the secondary reference level on limb current to provide compliance with basic restrictions on localized SAR averaged over 10 g. PMID:12222849

  15. Fine resolution calculations of SAR in the human body for frequencies up to 3 GHz

    NASA Astrophysics Data System (ADS)

    Dimbylow, P. J.

    2002-08-01

    Finite-difference time-domain (FDTD) calculations of whole-body averaged specific energy absorption rate (SAR) have been performed from 100 MHz to 3 GHz at the basic 2 mm resolution of the voxel (volume pixel) model NORMAN without any rescaling to larger cell sizes. The reduction in the voxel size from previous work allows SAR to be calculated at higher frequencies. Additionally, the calculations have been extended down to 10 MHz, covering the whole-body resonance regions at a resolution of 4 mm. As well as for the adult phantom, SAR values are calculated for scaled versions representing 10-, 5- and 1-year-old children for both grounded and isolated conditions. External electric field levels are derived from limits of whole-body averaged SAR and localized SAR in the ankle, and compared with NRPB investigation levels and ICNIRP reference levels. The ICNIRP field reference levels alone would not provide a conservative estimate of the localized SAR exposure in the leg for grounded conditions. It would be necessary to invoke the secondary reference level on limb current to provide compliance with basic restrictions on localized SAR averaged over 10 g.

  16. Mass Loss Rates for Solar-like Stars Measured from Lyα Absorption

    NASA Astrophysics Data System (ADS)

    Wood, B. E.; Müller, H.-R.; Linsky, J. L.

    2003-10-01

    We present a number of mass loss rate measurements for solar-like stars with coronal winds, computed using a Lyα absorption technique. The collision between the solar wind and the interstellar wind seen by the Sun defines the large scale structure of our heliosphere. Similar structures, ``astrospheres,'' exist around other solar-like stars. The deceleration of the interstellar wind at the solar or stellar bow shock heats the interstellar material. Heated neutral hydrogen in the outer astrosphere (and/or heliosphere) produces a broad Lyα absorption profile that is often detectable in high resolution Hubble Space Telescope spectra. The amount of absorption is dependent upon the strength of the stellar wind. With guidance from hydrodynamic models of astrospheres, we use detected astrospheric Lyα absorption to estimate the stellar mass loss rates. For the solar-like GK stars in our sample, mass loss appears to increase with stellar activity, suggesting that young, active stars have stronger winds than old, inactive stars. However, Proxima Cen (M5.5 Ve) and λ And (G8 IV-III+M V) appear to be inconsistent with this relation.

  17. Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

    NASA Astrophysics Data System (ADS)

    Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-03-01

    This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

  18. Absorption cross-section and decay rate of rotating linear dilaton black holes

    NASA Astrophysics Data System (ADS)

    Sakalli, I.; Aslan, O. A.

    2016-02-01

    We analytically study the scalar perturbation of non-asymptotically flat (NAF) rotating linear dilaton black holes (RLDBHs) in 4-dimensions. We show that both radial and angular wave equations can be solved in terms of the hypergeometric functions. The exact greybody factor (GF), the absorption cross-section (ACS), and the decay rate (DR) for the massless scalar waves are computed for these black holes (BHs). The results obtained for ACS and DR are discussed through graphs.

  19. Strain Rate Effects on the Energy Absorption of Rapidly Manufactured Composite Tubes

    SciTech Connect

    Brighton, Aaron M; Forrest, Mark; Starbuck, J Michael; ERDMAN III, DONALD L; Fox, Bronwyn

    2009-01-01

    Quasi-static and intermediate rate axial crush tests were conducted on tubular specimens of Carbon/Epoxy (Toray T700/G83C) and Glass/Polypropylene (Twintex). The quasi-static tests were conducted at 10 mm/min (1.67x10-4 m/s); five different crush initiators were used. Tests at intermediate rates were performed at speeds of 0.25 m/s, 0.5 m/s, 0.75 m/s 1m/s, 2 m/s and 4 m/s. Quasi-static tests of tubular specimens showed high specific energy absorption (SEA) values with 86 kJ/kg for Carbon/Epoxy specimens. The specific energy absorption of the Glass/Polypropylene specimens was measured to be 29 kJ/kg. Results from the intermediate test rates showed that while a decrease in specific energy absorbed was observed as speeds increased, values did not fall below 55kj/kg for carbon specimens or 35 kJ/kg for the Glass/Polypropylene specimens. When compared with steel and aluminium, specific energy absorption values of 15 kJ/kg and 30 kJ/kg respectively, the benefits of using composite materials in crash structures are apparent.

  20. Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects

    PubMed Central

    Panagopoulos, Dimitris J.; Johansson, Olle; Carlo, George L.

    2013-01-01

    Purpose To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. Methods We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. Results We find that: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. Conclusions SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict

  1. ERS-1 SAR data processing

    NASA Technical Reports Server (NTRS)

    Leung, K.; Bicknell, T.; Vines, K.

    1986-01-01

    To take full advantage of the synthetic aperature radar (SAR) to be flown on board the European Space Agency's Remote Sensing Satellite (ERS-1) (1989) and the Canadian Radarsat (1990), the implementation of a receiving station in Alaska is being studied to gather and process SAR data pertaining in particular to regions within the station's range of reception. The current SAR data processing requirement is estimated to be on the order of 5 minutes per day. The Interim Digital Sar Processor (IDP) which was under continual development through Seasat (1978) and SIR-B (1984) can process slightly more than 2 minutes of ERS-1 data per day. On the other hand, the Advanced Digital SAR Processore (ADSP), currently under development for the Shuttle Imaging Radar C (SIR-C, 1988) and the Venus Radar Mapper, (VMR, 1988), is capable of processing ERS-1 SAR data at a real time rate. To better suit the anticipated ERS-1 SAR data processing requirement, both a modified IDP and an ADSP derivative are being examined. For the modified IDP, a pipelined architecture is proposed for the mini-computer plus array processor arrangement to improve throughout. For the ADSP derivative, a simplified version is proposed to enhance ease of implementation and maintainability while maintaing real time throughput rates. These processing systems are discussed and evaluated.

  2. Imaging Breathing Rate in the CO2Absorption Band.

    PubMed

    Fei, Jin; Zhu, Zhen; Pavlidis, Ioannis

    2005-01-01

    Following up on our previous work, we have developed one more non-contact method to measure human breathing rate. We have retrofitted our Mid-Wave Infra-Red (MWIR) imaging system with a narrow band-pass filter in the CO2absorption band (4.3 µm). This improves the contrast between the foreground (i.e., expired air) and background (e.g., wall). Based on the radiation information within the breath flow region, we get the mean dynamic thermal signal. This signal is quasi-periodic due to the interleaving of high and low intensities corresponding to expirations and inspirations respectively. We sample the signal at a constant rate and then determine the breathing frequency through Fourier analysis. We have performed experiments on 9 subjects at distances ranging from 6-8 ft. We compared the breathing rate computed by our novel method with ground-truth measurements obtained via a traditional contact device (PowerLab/4SP from ADInstruments with an abdominal transducer). The results show high correlation between the two modalities. For the first time, we report a Fourier based breathing rate computation method on a MWIR signal in the CO2absorption band. The method opens the way for desktop, unobtrusive monitoring of an important vital sign, that is, breathing rate. It may find widespread applications in preventive medicine as well as sustained physiological monitoring of subjects suffering from chronic ailments. PMID:17282279

  3. Analysis of the local worst-case SAR exposure caused by an MRI multi-transmit body coil in anatomical models of the human body

    NASA Astrophysics Data System (ADS)

    Neufeld, Esra; Gosselin, Marie-Christine; Murbach, Manuel; Christ, Andreas; Cabot, Eugenia; Kuster, Niels

    2011-08-01

    Multi-transmit coils are increasingly being employed in high-field magnetic resonance imaging, along with a growing interest in multi-transmit body coils. However, they can lead to an increase in whole-body and local specific absorption rate (SAR) compared to conventional body coils excited in circular polarization for the same total incident input power. In this study, the maximum increase of SAR for three significantly different human anatomies is investigated for a large 3 T (128 MHz) multi-transmit body coil using numerical simulations and a (generalized) eigenvalue-based approach. The results demonstrate that the increase of SAR strongly depends on the anatomy. For the three models and normalization to the sum of the rung currents squared, the whole-body averaged SAR increases by up to a factor of 1.6 compared to conventional excitation and the peak spatial SAR (averaged over any 10 cm3 of tissue) by up to 13.4. For some locations the local averaged SAR goes up as much as 800 times (130 when looking only at regions where it is above 1% of the peak spatial SAR). The ratio of the peak spatial SAR to the whole-body SAR increases by a factor of up to 47 and can reach values above 800. Due to the potentially much larger power deposition, additional, preferably patient-specific, considerations are necessary to avoid injuries by such systems.

  4. Determination of methane emission rates on a biogas plant using data from laser absorption spectrometry.

    PubMed

    Groth, Angela; Maurer, Claudia; Reiser, Martin; Kranert, Martin

    2015-02-01

    The aim of the work was to establish a method for emission control of biogas plants especially the observation of fugitive methane emissions. The used method is in a developmental stage but the topic is crucial to environmental and economic issues. A remote sensing measurement method was adopted to determine methane emission rates of a biogas plant in Rhineland-Palatinate, Germany. An inverse dispersion model was used to deduce emission rates. This technique required one concentration measurement with an open path tunable diode laser absorption spectrometer (TDLAS) downwind and upwind the source and basic wind information, like wind speed and direction. Different operating conditions of the biogas plant occurring on the measuring day (December 2013) could be represented roughly in the results. During undisturbed operational modes the methane emission rate averaged 2.8 g/s, which corresponds to 4% of the methane gas production rate of the biogas plant. PMID:25446786

  5. Effective absorption cross sections and photolysis rates of anthropogenic and biogenic secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Romonosky, Dian E.; Ali, Nujhat N.; Saiduddin, Mariyah N.; Wu, Michael; Lee, Hyun Ji (Julie); Aiona, Paige K.; Nizkorodov, Sergey A.

    2016-04-01

    Mass absorption coefficient (MAC) values were measured for secondary organic aerosol (SOA) samples produced by flow tube ozonolysis and smog chamber photooxidation of a wide range of volatile organic compounds (VOC), specifically: α-pinene, β-pinene, β-myrcene, d-limonene, farnesene, guaiacol, imidazole, isoprene, linalool, ocimene, p-xylene, 1-methylpyrrole, and 2-methylpyrrole. Both low-NOx and high-NOx conditions were employed during the chamber photooxidation experiments. MAC values were converted into effective molecular absorption cross sections assuming an average molecular weight of 300 g/mol for SOA compounds. The upper limits for the effective photolysis rates of SOA compounds were calculated by assuming unity photolysis quantum yields and convoluting the absorption cross sections with a time-dependent solar spectral flux. A more realistic estimate for the photolysis rates relying on the quantum yield of acetone was also obtained. The results show that condensed-phase photolysis of SOA compounds can potentially occur with effective lifetimes ranging from minutes to days, suggesting that photolysis is an efficient and largely overlooked mechanism of SOA aging.

  6. New constraints in absorptive capacity and the optimum rate of petroleum output

    SciTech Connect

    El Mallakh, R

    1980-01-01

    Economic policy in four oil-producing countries is analyzed within a framework that combines a qualitative assessment of the policy-making process with an empirical formulation based on historical and current trends in these countries. The concept of absorptive capacity is used to analyze the optimum rates of petroleum production in Iran, Iraq, Saudi Arabia, and Kuwait. A control solution with an econometric model is developed which is then modified for alternative development strategies based on analysis of factors influencing production decisions. The study shows the consistencies and inconsistencies between the goals of economic growth, oil production, and exports, and the constraints on economic development. Simulation experiments incorporated a number of the constraints on absorptive capacity. Impact of other constraints such as income distribution and political stability is considered qualitatively. (DLC)

  7. Specific absorption rate calculations of magnetite, using a modified linear response model for applications in magnetic hyperthermia

    SciTech Connect

    Hernández S, A. E-mail: meduardo2001@hotmail.com; Cano, M. E. E-mail: meduardo2001@hotmail.com; Torres-Arenas, J.

    2014-11-07

    Currently the absorption of electromagnetic radiation by magnetic nanoparticles is studied for biomedical applications of cancer thermotherapy. Several experiments are conduced following the framework of the Rosensweig model, in order to estimate their specific absorption rate. Nevertheless, this linear approximation involves strong simplifications which constrain their accuracy and validity range. The main aim of this work is to incorporate the deviation of the sphericity assumption in particles shapes, to improve the determination of their specific absorption rate. The correction to the effective particles volume is computed as a measure of the apparent amount of magnetic material, interacting with the external AC magnetic field. Preliminary results using the physical properties of Fe3O4 nanoparticles, exhibit an important correction in their estimated specific absorption rate, as a function of the apparent mean particles radius. Indeed, we have observed using a small deviation (6% of the apparent radius), up to 40% of the predicted specific absorption rate by the Rosensweig linear approximation.

  8. COMPARISON OF FINITE-DIFFERENCE TIME DOMAIN SAR CALCULATIONS WITH MEASUREMENT IN A HETEROGENEOUS MODEL OF MAN

    EPA Science Inventory

    A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR) at various sites in a heterogeneous block model of man. he block model represented a close approximation to a full-scale heterogeneous phantom model. oth models were comprised of a ...

  9. The phase transition method for SAR measurement in MRI

    NASA Astrophysics Data System (ADS)

    Romano, Rocco; Acernese, Fausto; Vilasi, Silvia; Barone, Fabrizio

    2010-03-01

    During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2 - 33). The phase transition method is a new method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. On the other hand, it is necessary to establish if all deposited power SAR can be considered acquired and measured. In this paper, that will be shown.

  10. The phase transition method for SAR measurement in MRI

    NASA Astrophysics Data System (ADS)

    Romano, R.; Canonico, R.; Acernese, F.; Giordano, G.; Barone, F.

    2014-03-01

    During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2 - 33). The phase transition method is a new method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. Nevertheless, in order to consider this method it is necessary to verify that all deposited SAR power can be considered acquired and measured. In this paper considerations about this aspect are conducted.

  11. A no-calorimetric method for measuring SAR in MRI

    NASA Astrophysics Data System (ADS)

    Romano, Rocco; Acernese, Fausto; Barone, Fabrizio

    2011-04-01

    During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2 - 33). The phase transition method is a new no-calorimetric method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. On the other hand, it is necessary to establish if all deposited power SAR can be considered acquired and measured. In this paper, that will be shown.

  12. The relationship between localised SAR in the arm and wrist current.

    PubMed

    Dimbylow, P J

    2001-01-01

    Calculations are presented of the specific energy absorption rate, SAR, in the lower arm of the NRPB anatomically realistic voxel model. NORMAN, for induced currents from 100 kHz to 80 MHz. The wrist region has a narrow cross section and contains little high conductivity muscle, comprising mainly low conductivity bone, tendon and fat. Consequently there is a channelling of the current through the high conductivity muscle, which produces high, localised values of the SAR. Values averaged over 10 g and 100 g of tissue are calculated as a function of the current flowing through the wrist. PMID:11572647

  13. Temporal patterns of slip rate on the Little Lake fault, eastern California shear zone, from terrestrial lidar, cosmogenic radionuclides, and InSAR analysis (Invited)

    NASA Astrophysics Data System (ADS)

    Amos, C. B.; Burgmann, R.; Jayko, A. S.; Fisher, G., III; Rood, D. H.

    2010-12-01

    An ever-expanding inventory of fault slip-rates spanning various time intervals reveals contrasting spatial and temporal patterns of strain for active faults within the Eastern California shear zone (ECSZ). Comparison of data derived from geologic, geomorphic, and paleoseismic records with geodetic estimates of fault loading affords unparalleled opportunity to investigate the dynamics of earthquake processes and the evolution of an intracontinental plate boundary fault system. We focus here on the Little Lake fault, which lies along the western margin of the ECSZ between the Sierra Nevada and the Coso Range in east-central California. The fault accommodates between 10-20% of the total dextral motion within the ECSZ at this latitude and a smaller fraction of the relative motion between the Pacific and North American plates. Relatively high rates of decadal fault loading previously described for the Little Lake fault zone from GPS measurements and InSAR data suggest potential discrepancies with longer, late Quaternary records of fault slip. To address this inconsistency, we targeted a series of fluvial terraces related to overtopping and outflow from pluvial Owens Lake that cross the fault and record dextral offset since Late-Pleistocene time. High-resolution topographic surveying using a tripod-mounted laser scanner suggests between 33 and 38 m of reconstructed right-lateral displacement of two individual terrace risers over this time period. Coupled with cosmogenic 10Be dating of intact, meter-scale outwash boulders preserved on terrace treads bounding each riser, detailed characterization of these geomorphic features provides a robust geologic slip-rate estimate for the Little Lake fault zone at the ~104 year timescale. Preliminary correlation of terrace surfaces with available exposure dating of fluvially scoured basalt upstream at Fossil Falls suggests a right-lateral displacement-rate on the order of ~2 mm/yr. Although more than double the previously reported

  14. The absorption efficiency and respiration rate of the Florida lancelet, Branchiostoma floridae.

    PubMed

    Nash, Troy R; Ruppert, Edward E; Colacino, James M

    2009-12-01

    The present study investigates some aspects of the digestive biology and physiological energetics of the Florida lancelet, Branchiostoma floridae. Florida lancelets are able to remove 47.2-56.9% of the energy from a diet of mixed algae. The respiration rate is 0.100mL O(2) (STPD) h(-1) g(-1) (wet), which estimates a metabolic rate of 0.248 J h(-1), at an average body mass of 0.125 g (wet). Published values of the chlorophyll a concentration in its natural habitat indicate that a 125 mg lancelet would need to filter 0.018-0.031 L h(-1) to remove sufficient food to support its resting metabolism. The filtration rate of lancelets has been reported as 0.138 L h(-1), indicating that the actual filtration rate is 4-7 times greater than the filtration rate needed to meet resting metabolic demands. It appears that lancelets have the potential to be raised in aquaculture, because their absorption efficiency and respiration rate are comparable to suspension-feeding invertebrates that have been successfully aquacultured. PMID:19758577

  15. Outdoor measurement of SAR in a full-sized human model exposed to 29. 9 MHz in the near field

    SciTech Connect

    Olsen, R.G.; Griner, T.A.

    1989-01-01

    Localized and averaged specific absorption rates (SARs) were obtained in a full-size muscle-equivalent human model exposed to near-field 29.9 MHz irradiation at an outdoor facility. The model was positioned erect on a metallic groundplane 1.22 m (4 ft) from the base of a 10.8-m (35 ft) whip antenna with an input power of 1.0 kW. For whole-body SAR, a mean value of 0.83 W/kg was determined using two gradient-layer calorimeters in a twin-well configuration. The localized SARs at 12 body locations were measured using nonperturbing temperature probes and were highest in the ankle region. We conclude that averaged SAR measurements in a full-size phantom are feasible using a twin-calorimeter approach; measurements in the field are practical when human-size (183 x 61 x 46 cm) calorimeters are used.

  16. Confirmation of quasi-static approximation in SAR evaluation for a wireless power transfer system.

    PubMed

    Hirata, Akimasa; Ito, Fumihiro; Laakso, Ilkka

    2013-09-01

    The present study discusses the applicability of the magneto-quasi-static approximation to the calculation of the specific absorption rate (SAR) in a cylindrical model for a wireless power transfer system. Resonant coils with different parameters were considered in the 10 MHz band. A two-step quasi-static method that is comprised of the method of moments and the scalar-potential finite-difference methods is applied, which can consider the effects of electric and magnetic fields on the induced SAR separately. From our computational results, the SARs obtained from our quasi-static method are found to be in good agreement with full-wave analysis for different positions of the cylindrical model relative to the wireless power transfer system, confirming the applicability of the quasi-static approximation in the 10 MHz band. The SAR induced by the external electric field is found to be marginal as compared to that induced by the magnetic field. Thus, the dosimetry for the external magnetic field, which may be marginally perturbed by the presence of biological tissue, is confirmed to be essential for SAR compliance in the 10 MHz band or lower. This confirmation also suggests that the current in the coil rather than the transferred power is essential for SAR compliance. PMID:23939244

  17. Statistical Simulation of SAR Variability with Geometric and Tissue Property Changes by Using the Unscented Transform

    PubMed Central

    Shao, Yu; Zeng, Peng; Wang, Shumin

    2015-01-01

    Purpose The local specific absorption rate (SAR) is critical to the safety of radio frequency transmit coils. A statistical simulation approach is introduced to address the local SAR variability related to tissue property and geometric variations. Methods The local SAR is modeled as the output of a nonlinear transformation with factors that may affect its value being treated as random input variables. Instead of using the Monte Carlo method with a large number of sample points, the unscented transform is applied with a small set of deterministic sample points. A sensitivity analysis is further performed to determine the significance of each input variable. Electromagnetic simulations are carried out by the finite-difference time-domain method implemented on graphic processing unit. Results The local SAR variability of a 7 Tesla square loop coil for spine imaging and a 16-element brain imaging array as the result of tissue property and geometric changes were examined respectively. SAR limits were determined based on their means and standard deviations. Conclusion The proposed approach is efficient and general for the study of local SAR variability. PMID:25046818

  18. EEG electrode caps can reduce SAR induced in the head by GSM900 mobile phones.

    PubMed

    Hamblin, Denise L; Anderson, Vitas; McIntosh, Robert L; McKenzie, Ray J; Wood, Andrew W; Iskra, Steve; Croft, Rodney J

    2007-05-01

    This paper investigates the influence of EEG electrode caps on specific absorption rate (SAR) in the head from a GSM900 mobile phone (217-Hz modulation, peak power output 2 W). SAR measurements were recorded in an anthropomorphic phantom using a precision robotic system. Peak 10 g average SAR in the whole head and in just the temporal region was compared for three phantom arrangements; no cap, 64-electrode "Electro-Cap," and 64-electrode "Quick-Cap". Relative to the "no cap" arrangement, the Electro-Cap and Quick-Cap caused a peak SAR (10 g) reduction of 14% and 18% respectively in both the whole head and in the temporal region. Additional computational modeling confirmed that SAR (10 g) is reduced by the presence of electrode leads and that the extent of the effect varies according to the orientation of the leads with respect to the radiofrequency (RF) source. The modeling also indicated that the nonconductive shell between the electrodes and simulated head material does not significantly alter the electrode lead shielding effect. The observed SAR reductions are not likely to be sufficiently large to have accounted for null EEG findings in the past but should nonetheless be noted in studies aiming to measure and report human brain activity under similar exposure conditions. PMID:17518289

  19. SAR simulations for high-field MRI: how much detail, effort, and accuracy is needed?

    PubMed

    Wolf, S; Diehl, D; Gebhardt, M; Mallow, J; Speck, O

    2013-04-01

    Accurate prediction of specific absorption rate (SAR) for high field MRI is necessary to best exploit its potential and guarantee safe operation. To reduce the effort (time, complexity) of SAR simulations while maintaining robust results, the minimum requirements for the creation (segmentation, labeling) of human models and methods to reduce the time for SAR calculations for 7 Tesla MR-imaging are evaluated. The geometric extent of the model required for realistic head-simulations and the number of tissue types sufficient to form a reliable but simplified model of the human body are studied. Two models (male and female) of the virtual family are analyzed. Additionally, their position within the head-coil is taken into account. Furthermore, the effects of retuning the coils to different load conditions and the influence of a large bore radiofrequency-shield have been examined. The calculation time for SAR simulations in the head can be reduced by 50% without significant error for smaller model extent and simplified tissue structure outside the coil. Likewise, the model generation can be accelerated by reducing the number of tissue types. Local SAR can vary up to 14% due to position alone. This must be considered and sets a limit for SAR prediction accuracy. All these results are comparable between the two body models tested. PMID:22611018

  20. A simple parameterization of ozone infrared absorption for atmospheric heating rate calculations

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1991-01-01

    A simple parameterization of ozone absorption in the 9.6-micron region which is suitable for two- and three-dimensional stratospheric and tropospheric models is presented. The band is divided into two parts, a brand center region and a band wing region, grouping together regions for which the temperature dependence of absorption is similar. Each of the two regions is modeled with a function having the form of the Goody random model, with pressure and temperature dependent band parameters chosen by empirically fitting line-by-line equivalent widths for pressures between 0.25 and 1000 mbar and ozone absorber amounts between 1.0 x 10 to the -7th and 1.0 cm atm. The model has been applied to calculations of atmospheric heating rates using an absorber amount weighted mean pressure and temperature along the inhomogeneous paths necessary for flux computations. In the stratosphere, maximum errors in the heating rates relative to line-by-line calculations are 0.1 K/d, or 5 percent of the peak cooling at the stratopause. In the troposphere the errors are at most 0.005 K/d.

  1. Elementary reaction rate measurements at high temperatures by tunable-laser flash-absorption

    SciTech Connect

    Hessler, J.P.

    1993-12-01

    The major objective of this program is to measure thermal rate coefficients and branching ratios of elementary reactions. To perform these measurements, the authors constructed an ultrahigh-purity shock tube to generate temperatures between 1000 and 5500 K. The tunable-laser flash-absorption technique is used to measure the rate of change of the concentration of species which absorb below 50,000 cm{sup {minus}1} e.g.: OH, CH, and CH{sub 3}. This technique is being extended into the vacuum-ultraviolet spectral region where one can measure atomic species e.g.: H, D, C, O, and N; and diatomic species e.g.: O{sub 2}, CO, and OH.

  2. Chirp Scaling Algorithms for SAR Processing

    NASA Technical Reports Server (NTRS)

    Jin, M.; Cheng, T.; Chen, M.

    1993-01-01

    The chirp scaling SAR processing algorithm is both accurate and efficient. Successful implementation requires proper selection of the interval of output samples, which is a function of the chirp interval, signal sampling rate, and signal bandwidth. Analysis indicates that for both airborne and spaceborne SAR applications in the slant range domain a linear chirp scaling is sufficient. To perform nonlinear interpolation process such as to output ground range SAR images, one can use a nonlinear chirp scaling interpolator presented in this paper.

  3. BEHAVIRORAL EFFECTS OF MICROWAVES: RELATIONSHIP OF TOTAL DOSE AND DOSE RATE

    EPA Science Inventory

    The goal of the research was to compare the relationship of whole body averaged specific absorption rate (SAR) and specific absorption (SA) to determine whether dose rate or dose was the better predictor of biological effects. Sperm positive Long-Evans female rats were exposed to...

  4. Aquaporins in ovine amnion: responses to altered amniotic fluid volumes and intramembranous absorption rates.

    PubMed

    Cheung, Cecilia Y; Anderson, Debra F; Brace, Robert A

    2016-07-01

    Aquaporins (AQPs) are transmembrane channel proteins that facilitate rapid water movement across cell membranes. In amniotic membrane, the AQP-facilitated transfer of water across amnion cells has been proposed as a mechanism for amniotic fluid volume (AFV) regulation. To investigate whether AQPs modulate AFV by altering intramembranous absorption (IMA) rate, we tested the hypothesis that AQP gene expression in the amnion is positively correlated with IMA rate during experimental conditions when IMA rate and AFV are modified over a wide range. The relative abundances of AQP1, AQP3, AQP8, AQP9, and AQP11 mRNA and protein were determined in the amnion of 16 late-gestation ovine fetuses subjected to 2 days of control conditions, urine drainage, urine replacement, or intraamniotic fluid infusion. AQP mRNA levels were determined by RT-qPCR and proteins by western immunoblot. Under control conditions, mRNA levels among the five AQPs differed more than 20-fold. During experimental treatments, mean IMA rate in the experimental groups ranged from 100 ± 120 mL/day to 1370 ± 270 mL/day. The mRNA levels of the five AQPs did not change from control and were not correlated with IMA rates. The protein levels of AQP1 were positively correlated with IMA rates (r(2) = 38%, P = 0.01) while the remaining four AQPs were not. These findings demonstrate that five AQPs are differentially expressed in ovine amnion. Our study supports the hypothesis that AQP1 may play a positive role in regulating the rate of fluid transfer across the amnion, thereby participating in the dynamic regulation of AFV. PMID:27440743

  5. Effective light absorption and absolute electron transport rates in the coral Pocillopora damicornis.

    PubMed

    Szabó, Milán; Wangpraseurt, Daniel; Tamburic, Bojan; Larkum, Anthony W D; Schreiber, Ulrich; Suggett, David J; Kühl, Michael; Ralph, Peter J

    2014-10-01

    Pulse Amplitude Modulation (PAM) fluorometry has been widely used to estimate the relative photosynthetic efficiency of corals. However, both the optical properties of intact corals as well as past technical constrains to PAM fluorometers have prevented calculations of the electron turnover rate of PSII. We used a new Multi-colour PAM (MC-PAM) in parallel with light microsensors to determine for the first time the wavelength-specific effective absorption cross-section of PSII photochemistry, σII(λ), and thus PAM-based absolute electron transport rates of the coral photosymbiont Symbiodinium both in culture and in hospite in the coral Pocillopora damicornis. In both cases, σII of Symbiodinium was highest in the blue spectral region and showed a progressive decrease towards red wavelengths. Absolute values for σII at 440 nm were up to 1.5-times higher in culture than in hospite. Scalar irradiance within the living coral tissue was reduced by 20% in the blue when compared to the incident downwelling irradiance. Absolute electron transport rates of P. damicornis at 440 nm revealed a maximum PSII turnover rate of ca. 250 electrons PSII(-1) s(-1), consistent with one PSII turnover for every 4 photons absorbed by PSII; this likely reflects the limiting steps in electron transfer between PSII and PSI. Our results show that optical properties of the coral host strongly affect light use efficiency of Symbiodinium. Therefore, relative electron transport rates do not reflect the productivity rates (or indeed how the photosynthesis-light response is parameterised). Here we provide a non-invasive approach to estimate absolute electron transport rates in corals. PMID:25146689

  6. Low SAR planar antenna for multi standard cellular phones

    NASA Astrophysics Data System (ADS)

    Ben Ahmed, M.; Bouhorma, M.; Elouaai, F.; Mamouni, A.

    2011-03-01

    In this paper the design of a multiband compact antenna for the integration into the new multi function mobile phones is presented. The antenna is matched to operate at GSM 920 MHz, WI-Fi 2.4 GHz and HiperLan 5.1 GHz standards with low SAR levels. Return loss coefficient and radiation pattern of this antenna are computed in free space as well as in the presence of head. The specific absorption rate (SAR) of the planar antenna is calculated and compared with that of the monopole antenna. To examine the performance of this antenna, a prototype was designed, fabricated and measured; the simulation analysis was performed using the HFSS software, good agreement with the simulation providing validation of the design procedure.

  7. Fe /Fe oxide nanocomposite particles with large specific absorption rate for hyperthermia

    NASA Astrophysics Data System (ADS)

    Zeng, Q.; Baker, I.; Loudis, J. A.; Liao, Y.; Hoopes, P. J.; Weaver, J. B.

    2007-06-01

    Using a water-in-oil microemulsion with cetyl trimethyl ammonium bromide as the surfactant, iron was reduced to form a metallic core on which a passivating oxide shell was grown. Transmission electron microscopy, vibrating sample magnetometry, and heating measurements were used to characterize these monodispersed magnetic Fe /Fe3O4 composite nanoparticles with respect to the possible application for magnetic hyperthermia treatments of cancer. The aim is to utilize the fact that an iron core (high saturation magnetization) will give a greater heating effect than iron oxide, while the iron oxide coating will allow the nanoparticles to be observed using magnetic resonance imaging so that therapy can be effectively monitored and targeted. The largest specific absorption rate obtained was 345W/g under an alternating magnetic field of 150Oe at 250kHz.

  8. Quasi-static magnetic measurements to predict specific absorption rates in magnetic fluid hyperthermia experiments

    NASA Astrophysics Data System (ADS)

    Coral, D. F.; Mendoza Zélis, P.; de Sousa, M. E.; Muraca, D.; Lassalle, V.; Nicolás, P.; Ferreira, M. L.; Fernández van Raap, M. B.

    2014-01-01

    In this work, the issue on whether dynamic magnetic properties of polydispersed magnetic colloids modeled using physical magnitudes derived from quasi-static magnetic measurement can be extrapolated to analyze specific absorption rate data acquired at high amplitudes and frequencies of excitation fields is addressed. To this end, we have analyzed two colloids of magnetite nanoparticles coated with oleic acid and chitosan in water displaying, under a radiofrequency field, high and low specific heat power release. Both colloids are alike in terms of liquid carrier, surfactant and magnetic phase composition but differ on the nanoparticle structuring. The colloid displaying low specific dissipation consists of spaced magnetic nanoparticles of mean size around 4.8 nm inside a large chitosan particle of 52.5 nm. The one displaying high specific dissipation consists of clusters of magnetic nanoparticles of mean size around 9.7 nm inside a chitosan particle of 48.6 nm. The experimental evaluation of Néel and Brown relaxation times (˜10-10 s and 10-4 s, respectively) indicate that the nanoparticles in both colloids magnetically relax by Néel mechanism. The isothermal magnetization curves analysis for this mechanism show that the magnetic nanoparticles behave in the interacting superparamagnetic regime. The specific absorption rates were determined calorimetrically at 260 kHz and up to 52 kA/m and were well modeled within linear response theory using the anisotropy density energy retrieved from quasi-static magnetic measurement, validating their use to predict heating ability of a given polydispersed particle suspension. Our findings provide new insight in the validity of quasi-static magnetic characterization to analyze the high frequency behavior of polydispersed colloids within the framework of the linear response and Wohlfarth theories and indicate that dipolar interactions play a key role being their strength larger for the colloid displaying higher dissipation, i

  9. Experimental Evaluation of SAR around an Implanted Cardiac Pacemaker Caused by Mobile Radio Terminal

    NASA Astrophysics Data System (ADS)

    Endo, Yuta; Saito, Kazuyuki; Watanabe, Soichi; Takahashi, Masaharu; Ito, Koichi

    Although the effect of electromagnetic interference on an implanted cardiac pacemaker due to a nearby mobile phone has been investigated, there have been few studies on the enhancement of the specific absorption rate (SAR) around an implanted cardiac pacemaker due to a nearby mobile phone. In this study, the SAR distribution around a pacemaker model embedded in a parallelepiped torso phantom when a mobile phone was nearby was numerically calculated and experimentally measured. The results of both investigations showed a characteristic SAR distribution. The system presented can be used to estimate the effects of electromagnetic interference on implanted electric circuits and thus could lead to the development of guidelines for the safe use of mobile radio terminals near people with medical implants.

  10. Heat equation inversion framework for average SAR calculation from magnetic resonance thermal imaging.

    PubMed

    Alon, Leeor; Sodickson, Daniel K; Deniz, Cem M

    2016-10-01

    Deposition of radiofrequency (RF) energy can be quantified via electric field or temperature change measurements. Magnetic resonance imaging has been used as a tool to measure three dimensional small temperature changes associated with RF radiation exposure. When duration of RF exposure is long, conversion from temperature change to specific absorption rate (SAR) is nontrivial due to prominent heat-diffusion and conduction effects. In this work, we demonstrated a method for calculation of SAR via an inversion of the heat equation including heat-diffusion and conduction effects. This method utilizes high-resolution three dimensional magnetic resonance temperature images and measured thermal properties of the phantom to achieve accurate calculation of SAR. Accuracy of the proposed method was analyzed with respect to operating frequency of a dipole antenna and parameters used in heat equation inversion. Bioelectromagnetics. 37:493-503, 2016. © 2016 Wiley Periodicals, Inc. PMID:27490064

  11. Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine

    SciTech Connect

    Rowley, R.L.; Adams, M.E.; Marshall, T.L.; Oscarson, J.L.; Wilding, W.V.; Anderson, D.J.

    1997-03-01

    Natural gas processors use amine treating processes to remove the acid gases H{sub 2}S and CO{sub 2} from gas streams. Absorption rates of gaseous CO{sub 2} into aqueous N-methyldiethanolamine (MDEA) solutions were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. The absorption rate was found to be insensitive to the diffusion coefficient of CO{sub 2} in solution but very sensitive to the diffusion rate of bicarbonate and protonated MDEA ions. Evidence also suggested that chemical reaction equilibrium is rapid relative to diffusion. A numerical model was developed on the basis of these observations. The model was used to regress diffusion coefficients of bicarbonate and protonated amine, which must be equivalent by electroneutrality arguments, from measured absorption rates. Complete modeling of the absorption process also required data for the diffusion coefficient of MDEA in water. These were measured using a Taylor dispersion apparatus. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate and protonated MDEA were obtained at 298.2 K and 318.2 K in solutions containing 20, 35, and 50 mass % MDEA in water.

  12. Study of the influence of the laterality of mobile phone use on the SAR induced in two head models

    NASA Astrophysics Data System (ADS)

    Ghanmi, Amal; Varsier, Nadège; Hadjem, Abdelhamid; Conil, Emmanuelle; Picon, Odile; Wiart, Joe

    2013-05-01

    The objective of this paper is to investigate and to analyse the influence of the laterality of mobile phone use on the exposure of the brain to radio-frequencies (RF) and electromagnetic fields (EMF) from different mobile phone models using the finite-difference time-domain (FDTD) method. The study focuses on the comparison of the specific absorption rate (SAR) induced on the right and left sides of two numerical adult and child head models. The heads are exposed by both phone models operating in GSM frequency bands for both ipsilateral and contralateral configurations. A slight SAR difference between the two sides of the heads is noted. The results show that the variation between the left and the right sides is more important at 1800 MHz for an ipsilateral use. Indeed, at this frequency, the variation can even reach 20% for the SAR10g and the SAR1g induced in the head and in the brain, respectively. Moreover, the average SAR induced by the mobile phone in the half hemisphere of the brain in ipsilateral exposure is higher than in contralateral exposure. Owing to the superficial character of energy deposition at 1800 MHz, this difference in the SAR induced for the ipsilateral and contralateral usages is more significant at 1800 MHz than at 900 MHz. The results have shown that depending on the phantom head models, the SAR distribution in the brain can vary because of differences in anatomical proportions and in the geometry of the head models. The induced SAR in child head and in sub-regions of the brain is significantly higher (up to 30%) compared to the adult head. This paper confirms also that the shape/design of the mobile and the location of the antenna can have a large influence at high frequency on the exposure of the brain, particularly on the SAR distribution and on the distinguished brain regions.

  13. Measurement and validation of GHz-band whole-body average SAR in a human volunteer using reverberation chamber

    NASA Astrophysics Data System (ADS)

    Wang, Jianqing; Suzuki, Tokio; Fujiwara, Osamu; Harima, Katsushige

    2012-12-01

    The World Health Organization’s (WHO) recommendation on the need for further research for radio-frequency dosimetry has promoted studies on the whole-body average-specific absorption rate (WBA-SAR) in various kinds of anatomical-based numerical models. For experimental validation of GHz-band WBA-SARs in a real human, however, there have not so far been any published papers, despite the fact that, in 1982, Hill measured WBA-SARs at frequencies less than 40 MHz in human volunteers using a TEM-cell exposure system. In this study, we provide a measurement technique with a reverberation chamber for validating numerical dosimetry results on GHz-band WBA-SARs in living humans. We measured WBA-SARs at 1, 1.5 and 2 GHz for a 22 year old male volunteer, with a height of 173 cm and a weight of 73 kg, in the reverberation chamber, and compared the results with the finite-difference time-domain (FDTD) simulation. The reverberation chamber was excited by using a signal generator through an amplifier with an output power of 30-40 mW, which produced inside the chamber with the volunteer an average electric field strength of 5 V m-1 equivalent to an average power spectral density of 6.6 μW cm-2. The WBA-SARs were obtained from the measured S11 and S21 together with the power density. On the other hand, the WBA-SARs have been calculated using the FDTD method for an adult male model with almost the same physique as that of the volunteer exposed to the electromagnetic field in the reverberation chamber. From the comparison between the measured and the calculated WBA-SARs, we could confirm that the measured GHz-band WBA-SARs approximately agree with the FDTD calculated results.

  14. SiSAR: advanced SAR simulation

    NASA Astrophysics Data System (ADS)

    Klaus, Ferdinand

    1995-11-01

    SiSAR was planned as a realistic as possible, modular, user-friendly and fast SAR raw data simulator running on ordinary workstations. Interest in (interferometric) SAR products is growing on an international scale. There is a concentration of manpower and financial resources. Dead ends, respectively failures, have to be avoided during design and mission of every SAR project by simulating the system thoroughly before the experiment. Another reason to make use of extensive reproducible simulations during design and development is the reduction of time and manpower costs. As it comes down to verifying and comparing different processing algorithms we see that (interferometric) SAR simulation is an indispensable tool for testing individual processing steps. SiSAR is a modular SAR raw data simulator for realistic description of the functions of a SAR-system. It contains an implementation of diverse models to characterize radar targets, various approaches to describe the trajectory and the motion of the footprint on the target surface and different raw data formation algorithms. Beyond there is a wide supply of tools for manipulation, analysis and user-friendly simulation handling. Results obtained by SiSAR and some first simulated interferometric SAR raw data are shown in the paper.

  15. Cigarette smoking and rate of gastric emptying: effect on alcohol absorption.

    PubMed Central

    Johnson, R D; Horowitz, M; Maddox, A F; Wishart, J M; Shearman, D J

    1991-01-01

    OBJECTIVE--To examine the effects of cigarette smoking on alcohol absorption and gastric emptying. DESIGN--Randomised crossover study. SETTING--Research project in departments of medicine and nuclear medicine. SUBJECTS--Eight healthy volunteers aged 19-43 who regularly smoked 20-35 cigarettes a day and drank small amounts of alcohol on social occasions. INTERVENTIONS--Subjects drank 400 ml of a radiolabelled nutrient test meal containing alcohol (0.5 g/kg), then had their rates of gastric emptying measured. Test were carried out (a) with the subjects smoking four cigarettes an hour and (b) with the subjects not smoking, having abstained for seven days or more. The order of the tests was randomised and the tests were conducted two weeks apart. MAIN OUTCOME MEASURES--Peak blood alcohol concentrations, absorption of alcohol at 30 minutes, amount of test meal emptied from the stomach at 30 minutes, and times taken for 50% of the meal to leave the proximal stomach and total stomach. RESULTS--Smoking was associated with reductions in (a) peak blood alcohol concentrations (median values in non-smoking versus smoking periods 13.5 (range 8.7-22.6) mmol/l v 11.1 (4.3-13.5) mmol/l), (b) area under the blood alcohol concentration-time curve at 30 minutes (264 x 10(3) (0-509 x 10(3)) mmol/l/min v 140 x 10(3)) (0-217 x 10(3) mmol/l/min), and (c) amount of test meal emptied from the stomach at 30 minutes (39% (5-86%) v 23% (0-35%)). In addition, smoking slowed both the 50% gastric emptying time (37 (9-83) minutes v 56 (40-280) minutes) and the intragastric distribution of the meal. There was a close correlation between the amount of test meal emptied from the stomach at 30 minutes and the area under the blood alcohol concentration-time curve at 30 minutes (r = 0.91; p less than 0.0001). CONCLUSION--Cigarette smoking slows gastric emptying and as a consequence delays alcohol absorption. PMID:1991182

  16. Severe acute respiratory syndrome (SARS)

    MedlinePlus

    ... when the virus spread from small mammals in China. When someone with SARS coughs or sneezes, infected ... causes SARS include: Antibody tests for SARS Direct isolation of the SARS virus Rapid polymerase chain reaction ( ...

  17. NOTE: SAR in a child voxel phantom from exposure to wireless computer networks (Wi-Fi)

    NASA Astrophysics Data System (ADS)

    Findlay, R. P.; Dimbylow, P. J.

    2010-08-01

    Specific energy absorption rate (SAR) values have been calculated in a 10 year old sitting voxel model from exposure to electromagnetic fields at 2.4 and 5 GHz, frequencies commonly used by Wi-Fi devices. Both plane-wave exposure of the model and irradiation from antennas in the near field were investigated for a variety of exposure conditions. In all situations studied, the SAR values calculated were considerably below basic restrictions. For a typical Wi-Fi exposure scenario using an inverted F antenna operating at 100 mW, a duty factor of 0.1 and an antenna-body separation of 34 cm, the maximum peak localized SAR was found to be 3.99 mW kg-1 in the torso region. At 2.4 GHz, using a power of 100 mW and a duty factor of 1, the highest localized SAR value in the head was calculated as 5.7 mW kg-1. This represents less than 1% of the SAR previously calculated in the head for a typical mobile phone exposure condition.

  18. A multichannel, real-time MRI RF power monitor for independent SAR determination

    PubMed Central

    El-Sharkawy, AbdEl-Monem M.; Qian, Di; Bottomley, Paul A.; Edelstein, William A.

    2012-01-01

    Purpose: Accurate measurements of the RF power delivered during clinical MRI are essential for safety and regulatory compliance, avoiding inappropriate restrictions on clinical MRI sequences, and for testing the MRI safety of peripheral and interventional devices at known RF exposure levels. The goal is to make independent RF power measurements to test the accuracy of scanner-reported specific absorption rate (SAR) over the extraordinary range of operating conditions routinely encountered in MRI. Methods: A six channel, high dynamic range, real-time power profiling system was designed and built for monitoring power delivery during MRI up to 440 MHz. The system was calibrated and used in two 3 T scanners to measure power applied to human subjects during MRI scans. The results were compared with the scanner-reported SAR. Results: The new power measurement system has highly linear performance over a 90 dB dynamic range and a wide range of MRI duty cycles. It has about 0.1 dB insertion loss that does not interfere with scanner operation. The measurements of whole-body SAR in volunteers showed that scanner-reported SAR was significantly overestimated by up to about 2.2 fold. Conclusions: The new power monitor system can accurately and independently measure RF power deposition over the wide range of conditions routinely encountered during MRI. Scanner-reported SAR values are not appropriate for setting exposure limits during device or pulse sequence testing. PMID:22559603

  19. SAR in a child voxel phantom from exposure to wireless computer networks (Wi-Fi).

    PubMed

    Findlay, R P; Dimbylow, P J

    2010-08-01

    Specific energy absorption rate (SAR) values have been calculated in a 10 year old sitting voxel model from exposure to electromagnetic fields at 2.4 and 5 GHz, frequencies commonly used by Wi-Fi devices. Both plane-wave exposure of the model and irradiation from antennas in the near field were investigated for a variety of exposure conditions. In all situations studied, the SAR values calculated were considerably below basic restrictions. For a typical Wi-Fi exposure scenario using an inverted F antenna operating at 100 mW, a duty factor of 0.1 and an antenna-body separation of 34 cm, the maximum peak localized SAR was found to be 3.99 mW kg(-1) in the torso region. At 2.4 GHz, using a power of 100 mW and a duty factor of 1, the highest localized SAR value in the head was calculated as 5.7 mW kg(-1). This represents less than 1% of the SAR previously calculated in the head for a typical mobile phone exposure condition. PMID:20647607

  20. SAR measurement due to mobile phone exposure in a simulated biological media.

    PubMed

    Behari, J; Nirala, Jay Prakash

    2012-09-01

    The specific absorption rate (SAR) measurements are carried out for compliance testing of personal 3G Mobile phone. The accuracy of this experimental setup has been checked by comparing the SAR in 10 gm of simulated tissue and an arbitrary shaped box. This has been carried out using a 3G mobile Phone at 1718.5 MHz, in a medium simulating brain and muscle phantom. The SAR measurement system consists of a stepper motor to move a monopole E-field probe in two dimensions inside an arbitrary shaped box. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity). That is close to the average for gray and white matters of the brain at the frequencies of interest (1718.5 MHz). Induced fields are measured using a specially designed monopole probe in its close vicinity. The probe is immersed in the phantom material. The measured data for induced fields are used to compute SAR values at various locations with respect to the mobile phone location. It is concluded that these SAR values are position dependent and well below the safety criteria prescribed for human exposure. PMID:22897400

  1. A multichannel, real-time MRI RF power monitor for independent SAR determination

    SciTech Connect

    El-Sharkawy, AbdEl-Monem M.; Qian Di; Bottomley, Paul A.; Edelstein, William A.

    2012-05-15

    Purpose: Accurate measurements of the RF power delivered during clinical MRI are essential for safety and regulatory compliance, avoiding inappropriate restrictions on clinical MRI sequences, and for testing the MRI safety of peripheral and interventional devices at known RF exposure levels. The goal is to make independent RF power measurements to test the accuracy of scanner-reported specific absorption rate (SAR) over the extraordinary range of operating conditions routinely encountered in MRI. Methods: A six channel, high dynamic range, real-time power profiling system was designed and built for monitoring power delivery during MRI up to 440 MHz. The system was calibrated and used in two 3 T scanners to measure power applied to human subjects during MRI scans. The results were compared with the scanner-reported SAR. Results: The new power measurement system has highly linear performance over a 90 dB dynamic range and a wide range of MRI duty cycles. It has about 0.1 dB insertion loss that does not interfere with scanner operation. The measurements of whole-body SAR in volunteers showed that scanner-reported SAR was significantly overestimated by up to about 2.2 fold. Conclusions: The new power monitor system can accurately and independently measure RF power deposition over the wide range of conditions routinely encountered during MRI. Scanner-reported SAR values are not appropriate for setting exposure limits during device or pulse sequence testing.

  2. Assessment of induced SAR in children exposed to electromagnetic plane waves between 10 MHz and 5.6 GHz

    NASA Astrophysics Data System (ADS)

    Bakker, J. F.; Paulides, M. M.; Christ, A.; Kuster, N.; van Rhoon, G. C.

    2010-06-01

    To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels from the basic restrictions on the induced whole-body-averaged specific absorption rate (SARwb) and the peak 10 g spatial-averaged SAR (SAR10g). The objective of this study is to assess if the SAR in children remains below the basic restrictions upon exposure at the reference levels. Finite difference time domain (FDTD) modeling was used to calculate the SAR in six children and two adults when exposed to all 12 orthogonal plane wave configurations. A sensitivity study showed an expanded uncertainty of 53% (SARwb) and 58% (SAR10g) due to variations in simulation settings and tissue properties. In this study, we found that the basic restriction on the SARwb is occasionally exceeded for children, up to a maximum of 45% in small children. The maximum SAR10g values, usually found at body protrusions, remain under the limit for all scenarios studied. Our results are in good agreement with the literature, suggesting that the recommended ICNIRP reference levels may need fine tuning.

  3. SAR Reduction in 7T C-Spine Imaging Using a “Dark Modes” Transmit Array Strategy

    PubMed Central

    Eryaman, Yigitcan; Guerin, Bastien; Keil, Boris; Mareyam, Azma; Herraiz, Joaquin L.; Kosior, Robert K.; Martin, Adrian; Torrado-Carvajal, Angel; Malpica, Norberto; Hernandez-Tamames, Juan A.; Schiavi, Emanuele; Adalsteinsson, Elfar; Wald, Lawrence L.

    2016-01-01

    Purpose Local specific absorption rate (SAR) limits many applications of parallel transmit (pTx) in ultra high-field imaging. In this Note, we introduce the use of an array element, which is intentionally inefficient at generating spin excitation (a “dark mode”) to attempt a partial cancellation of the electric field from those elements that do generate excitation. We show that adding dipole elements oriented orthogonal to their conventional orientation to a linear array of conventional loop elements can lower the local SAR hotspot in a C-spine array at 7 T. Methods We model electromagnetic fields in a head/torso model to calculate SAR and excitation B1+ patterns generated by conventional loop arrays and loop arrays with added electric dipole elements. We utilize the dark modes that are generated by the intentional and inefficient orientation of dipole elements in order to reduce peak 10g local SAR while maintaining excitation fidelity. Results For B1+ shimming in the spine, the addition of dipole elements did not significantly alter the B1+ spatial pattern but reduced local SAR by 36%. Conclusion The dipole elements provide a sufficiently complimentary B1+ and electric field pattern to the loop array that can be exploited by the radiofrequency shimming algorithm to reduce local SAR. PMID:24753012

  4. SAR compliance assessment of PMR 446 and FRS walkie-talkies.

    PubMed

    Vermeeren, Günter; Joseph, Wout; Martens, Luc

    2015-10-01

    The vast amount of studies on radiofrequency dosimetry deal with exposure due to mobile devices and base station antennas for cellular communication systems. This study investigates compliance of walkie-talkies to exposure guidelines established by the International Commission on Non-Ionizing Radiation Protection and the Federal Communications Committee. The generic walkie-talkie consisted of a helical antenna and a ground plane and was derived by reverse engineering of a commercial walkie-talkie. Measured and simulated values of antenna characteristics and electromagnetic near fields of the generic walkie-talkie were within 2% and 8%, respectively. We also validated normalized electromagnetic near fields of the generic walkie-talkie against a commercial device and observed a very good agreement (deviation <6%). We showed that peak localized specific absorption rate (SAR) induced in the oval flat phantom by the generic walkie-talkie is in agreement with four commercial devices if input power of the generic walkie-talkie is rescaled based on magnetic near field. Finally, we found that SAR of commercial devices is within current SAR limits for general public exposure for a worst-case duty cycle of 100%, that is, about 3 times and 6 times lower than the limit on the 1 g SAR (1.6 W/kg) and 10 g SAR (2 W/kg), respectively. But, an effective radiated power as specified by the Private Mobile Radio at 446 MHz (PMR 446) radio standard can cause localized SAR exceeding SAR limits for 1 g of tissue. PMID:26344699

  5. Potential chlorofluorocarbon replacements: OH reaction rate constants between 250 and 315 K and infrared absorption spectra

    SciTech Connect

    Garland, N.L.; Medhurst, L.J.; Nelson, H.H.

    1993-12-20

    The authors measured the rate constant for reactions of the OH radical with several potential chlorofluorocarbon replacements over the temperature range 251-314 K using laser photolysis laser-induced fluorescence techniques. The compounds studied and Arrhenius parameters determined from fits to the measured rate constants are as follows: CHF{sub 2}OCHF{sub 2} (E 134), k(T) = (5.4 {+-} 3.5) x 10{sup {minus}13} cm{sup 3} s{sup {minus}1} exp [({minus}3.1 {+-} 0.4 kcal mol{sup {minus}1})/RT]; CF{sub 3}CH{sub 2}CF{sub 3} (FC 236fa), k(T) = (2.0 {+-} 1.0) x 10{sup {minus}14} cm{sup 3} s{sup {minus}1} exp [({minus}1.8 {+-} 0.3 kcal mol{sup {minus}1})/RT]; CF{sub 3}CHFCHF{sub 2} (FC 236ea), k(T) = (2.0 {+-} 0.9) x 10{sup {minus}13} cm{sup 3} s{sup {minus}1} exp [({minus}2.0 {+-} 0.3 kcal mol{sup {minus}1})/RT]; and CF{sub 3}CF{sub 2}CH{sub 2}F (FC 236cb), k(T) = (2.6 {+-} 1.6) x 10{sup {minus}13} cm{sup 3} s{sup {minus}1} exp [({minus}2.2 {+-} 0.4 kcal mol{sup {minus}1})/RT]. The measured activation energies (2-3 kcal mol{sup {minus}1}) are consistent with a mechanism of H atom abstraction. The tropospheric lifetimes, estimated from the measured OH reaction rates, and measured integrated infrared absorption cross sections over the range 770 to 1430 cm{sup {minus}1} suggest that E 134 and FC 236fa may have significant global warming potential, while FC 236ea and FC 236cb do not. 17 refs., 4 figs., 3 tabs.

  6. Association of acute adverse effects with high local SAR induced in the brain from prolonged RF head and neck hyperthermia

    NASA Astrophysics Data System (ADS)

    Adibzadeh, F.; Verhaart, R. F.; Verduijn, G. M.; Fortunati, V.; Rijnen, Z.; Franckena, M.; van Rhoon, G. C.; Paulides, M. M.

    2015-02-01

    To provide an adequate level of protection for humans from exposure to radio-frequency (RF) electromagnetic fields (EMF) and to assure that any adverse health effects are avoided. The basic restrictions in terms of the specific energy absorption rate (SAR) were prescribed by IEEE and ICNIRP. An example of a therapeutic application of non-ionizing EMF is hyperthermia (HT), in which intense RF energy is focused at a target region. Deep HT in the head and neck (H&N) region involves inducing energy at 434 MHz for 60 min on target. Still, stray exposure of the brain is considerable, but to date only very limited side-effects were observed. The objective of this study is to investigate the stringency of the current basic restrictions by relating the induced EM dose in the brain of patients treated with deep head and neck (H&N) HT to the scored acute health effects. We performed a simulation study to calculate the induced peak 10 g spatial-averaged SAR (psSAR10g) in the brains of 16 selected H&N patients who received the highest SAR exposure in the brain, i.e. who had the minimum brain-target distance and received high forwarded power during treatment. The results show that the maximum induced SAR in the brain of the patients can exceed the current basic restrictions (IEEE and ICNIRP) on psSAR10g for occupational environments by 14 times. Even considering the high local SAR in the brain, evaluation of acute effects by the common toxicity criteria (CTC) scores revealed no indication of a serious acute neurological effect. In addition, this study provides pioneering quantitative human data on the association between maximum brain SAR level and acute adverse effects when brains are exposed to prolonged RF EMF.

  7. Calculated SAR distributions in a human voxel phantom due to the reflection of electromagnetic fields from a ground plane between 65 MHz and 2 GHz

    NASA Astrophysics Data System (ADS)

    Findlay, R. P.; Dimbylow, P. J.

    2008-05-01

    If an electromagnetic field is incident normally onto a perfectly conducting ground plane, the field is reflected back into the domain. This produces a standing wave above the ground plane. If a person is present within the domain, absorption of the field in the body may cause problems regarding compliance with electromagnetic guidelines. To investigate this, the whole-body averaged specific energy absorption rate (SAR), localised SAR and ankle currents in the voxel model NORMAN have been calculated for a variety of these exposures under grounded conditions. The results were normalised to the spatially averaged field, a technique used to determine a mean value for comparison with guidelines when the field varies along the height of the body. Additionally, the external field values required to produce basic restrictions for whole-body averaged SAR have been calculated. It was found that in all configurations studied, the ICNIRP reference levels and IEEE MPEs provided a conservative estimate of these restrictions.

  8. Recovering Seasat SAR Data

    NASA Astrophysics Data System (ADS)

    Logan, T. A.; Arko, S. A.; Rosen, P. A.

    2013-12-01

    To demonstrate the feasibility of orbital remote sensing for global ocean observations, NASA launched Seasat on June 27th, 1978. Being the first space borne SAR mission, Seasat produced the most detailed SAR images of Earth from space ever seen to that point in time. While much of the data collected in the USA was processed optically, a mere 150 scenes had been digitally processed by March 1980. In fact, only an estimated 3% of Seasat data was ever digitally processed. Thus, for over three decades, the majority of the SAR data from this historic mission has been dormant, virtually unavailable to scientists in the 21st century. Over the last year, researchers at the Alaska Satellite Facility (ASF) Distributed Active Archive Center (DAAC) have processed the Seasat SAR archives into imagery products. A telemetry decoding system was created and the data were filtered into readily processable signal files. Due to nearly 35 years of bit rot, the bit error rate (BER) for the ASF DAAC Seasat archives was on the order of 1 out of 100 to 1 out of 100,000. This extremely high BER initially seemed to make much of the data undecodable - because the minor frame numbers are just 7 bits and no range line numbers exist in the telemetry even the 'simple' tasks of tracking the minor frame number or locating the start of each range line proved difficult. Eventually, using 5 frame numbers in sequence and a handful of heuristics, the data were successfully decoded into full range lines. Concurrently, all metadata were stored into external files. Recovery of this metadata was also problematic, the BER making the information highly suspect and, initially at least, unusable in any sort of automated fashion. Because of the BER, all of the single bit metadata fields proved unreliable. Even fields that should be constant for a data take (e.g. receiving station, day of the year) showed high variability, each requiring a median filter to be usable. The most challenging, however, were the

  9. Influence of dentures on SAR in the visible Chinese human head voxel phantom exposed to a mobile phone at 900 and 1800 MHz.

    PubMed

    Yu, Dong; Zhang, Ruoyu; Liu, Qian

    2012-09-01

    To investigate the influence of dentures on electromagnetic energy absorption during the daily use of a mobile phone, a high-resolution head phantom based on the Visible Chinese Human dataset was reconstructed. Simulations on phantoms with various dentures were performed by using the finite-difference time-domain method with a 0.47 wavelength dipole antenna and a mobile phone model as radiation sources at 900 and 1800 MHz. The Specific energy Absorption Rate (SAR) values including 1 and 10 g average SAR values were assessed. When the metallic dental crowns with resonance lengths of approximately one-third to one-half wavelength in the tissue nearby are parallel to the radiation source, up to 121.6% relative enhancement for 1 g average SAR and 17.1% relative enhancement for 10 g average SAR are observed due to the resonance effect in energy absorption. When the radiation sources operate in the normal configuration, the 10 g average SAR values are still in compliance with the basic restrictions established by the Institute of Electrical and Electronic Engineers (IEEE) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), indicating that the safety limits will not be challenged by the usage of dentures. PMID:22388567

  10. SAR Product Control Software

    NASA Astrophysics Data System (ADS)

    Meadows, P. J.; Hounam, D.; Rye, A. J.; Rosich, B.; Börner, T.; Closa, J.; Schättler, B.; Smith, P. J.; Zink, M.

    2003-03-01

    As SAR instruments and their operating modes become more complex, as new applications place more and more demands on image quality and as our understanding of their imperfections becomes more sophisticated, there is increasing recognition that SAR data quality has to be controlled more completely to keep pace. The SAR product CONtrol software (SARCON) is a comprehensive SAR product control software suite tailored to the latest generation of SAR sensors. SARCON profits from the most up-to-date thinking on SAR image performance derived from other spaceborne and airborne SAR projects and is based on the newest applications. This paper gives an overview of the structure and the features of this new software tool, which is a product of a co-operation between teams at BAE SYSTEMS Advanced Technology Centre and DLR under contract to ESA (ESRIN). Work on SARCON began in 1999 and is continuing.

  11. SAR change detection MTI

    NASA Astrophysics Data System (ADS)

    Scarborough, Steven; Lemanski, Christopher; Nichols, Howard; Owirka, Gregory; Minardi, Michael; Hale, Todd

    2006-05-01

    This paper examines the theory, application, and results of using single-channel synthetic aperture radar (SAR) data with Moving Reference Processing (MRP) to focus and geolocate moving targets. Moving targets within a standard SAR imaging scene are defocused, displaced, or completely missing in the final image. Building on previous research at AFRL, the SAR-MRP method focuses and geolocates moving targets by reprocessing the SAR data to focus the movers rather than the stationary clutter. SAR change detection is used so that target detection and focusing is performed more robustly. In the cases where moving target returns possess the same range versus slow-time histories, a geolocation ambiguity results. This ambiguity can be resolved in a number of ways. This paper concludes by applying the SAR-MRP method to high-frequency radar measurements from persistent continuous-dwell SAR observations of a moving target.

  12. Between-country comparison of whole-body SAR from personal exposure data in Urban areas.

    PubMed

    Joseph, Wout; Frei, Patrizia; Röösli, Martin; Vermeeren, Günter; Bolte, John; Thuróczy, György; Gajšek, Peter; Trček, Tomaž; Mohler, Evelyn; Juhász, Péter; Finta, Viktoria; Martens, Luc

    2012-12-01

    In five countries (Belgium, Switzerland, Slovenia, Hungary, and the Netherlands), personal radio frequency electromagnetic field measurements were performed in different microenvironments such as homes, public transports, or outdoors using the same exposure meters. From the mean personal field exposure levels (excluding mobile phone exposure), whole-body absorption values in a 1-year-old child and adult male model were calculated using a statistical multipath exposure method and compared for the five countries. All mean absorptions (maximal total absorption of 3.4 µW/kg for the child and 1.8 µW/kg for the adult) were well below the International Commission on Non-Ionizing Radiation Protection (ICNIRP) basic restriction of 0.08 W/kg for the general public. Generally, incident field exposure levels were well correlated with whole-body absorptions (SAR(wb) ), although the type of microenvironment, frequency of the signals, and dimensions of the considered phantom modify the relationship between these exposure measures. Exposure to the television and Digital Audio Broadcasting band caused relatively higher SAR(wb) values (up to 65%) for the 1-year-old child than signals at higher frequencies due to the body size-dependent absorption rates. Frequency Modulation (FM) caused relatively higher absorptions (up to 80%) in the adult male. PMID:22674152

  13. Millimeter-wave absorption by cutaneous blood vessels: a computational study.

    PubMed

    Alekseev, Stanislav I; Ziskin, Marvin C

    2009-10-01

    The aims of the present study were to calculate the specific absorption rate (SAR) and E-field distributions inside cutaneous blood vessels and in surrounding tissues (dermis and fat) depending on the frequency of millimeter wave exposure. Most calculations were performed using the finite-difference time-domain (FDTD) technique. A rectangular block of homogeneous or multilayer tissue with blood vessels located in the center of the block was used as the basic geometry. We found that the SAR reached its maximal value in a long blood vessel oriented parallel to the E-field. It exceeded the SAR in the surrounding dermis by 40%-42% at 42.25 GHz. However, in the same blood vessel oriented perpendicularly to the E-field, the SAR was lower than that of the surrounding dermis. Absorption of millimeter waves in a cutaneous blood vessel was higher at 61.22 GHz than at 42.25 GHz. The SAR distribution in a blood vessel was nearly uniform. Because of the small sizes of cutaneous blood vessels relative to the wavelength, the SAR distributions in these blood vessels can be calculated by using quasi-static theory. PMID:19527954

  14. SAR distribution in a bio-medium in close proximity with dual segment cylindrical dielectric resonator antenna.

    PubMed

    Gangwar, R K; Singh, S P; Kumar, D

    2012-05-01

    This paper reports simulation and experimental studies of input characteristics of a dual segment cylindrical dielectric resonator antenna (DSCDRA) in free space and in the presence of a bio-medium (synthetic muscle) along with specific absorption rate (SAR) distribution in the synthetic muscle medium due to the antenna at microwave frequencies. The simulation study has been carried out using CST Microwave Studio software. The experimental SAR distribution has been obtained using two 50 Ω L-shaped and straight coaxial probes and Agilent 3 Hz-50 GHz spectrum analyser. The experimental results for variation in return loss versus frequency for the DSCDRA and SAR distribution in synthetic muscle medium due to the antenna are compared with simulated results. PMID:22506808

  15. The generation of simple compliance boundaries for mobile communication base station antennas using formulae for SAR estimation.

    PubMed

    Thors, B; Hansson, B; Törnevik, C

    2009-07-01

    In this paper, a procedure is proposed for generating simple and practical compliance boundaries for mobile communication base station antennas. The procedure is based on a set of formulae for estimating the specific absorption rate (SAR) in certain directions around a class of common base station antennas. The formulae, given for both whole-body and localized SAR, require as input the frequency, the transmitted power and knowledge of antenna-related parameters such as dimensions, directivity and half-power beamwidths. With knowledge of the SAR in three key directions it is demonstrated how simple and practical compliance boundaries can be generated outside of which the exposure levels do not exceed certain limit values. The conservativeness of the proposed procedure is discussed based on results from numerical radio frequency (RF) exposure simulations with human body phantoms from the recently developed Virtual Family. PMID:19531847

  16. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

    PubMed

    Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

    2016-01-01

    The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m  and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart  mobile phones at the frequencies of 900 and 1800 MHz  was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone. PMID:27157169

  17. Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption.

    PubMed

    Covens, P; Berus, D; Caveliers, V; Struelens, L; Vanhavere, F; Verellen, D

    2013-06-01

    Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity Hp(0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption. PMID:23519114

  18. Abnormal oral glucose tolerance and glucose malabsorption after vagotomy and pyloroplasty. A tracer method for measuring glucose absorption rates

    SciTech Connect

    Radziuk, J.; Bondy, D.C.

    1982-11-01

    The mechanisms underlying the abnormal glucose tolerance in patients who had undergone vagotomy and pyloroplasty were investigated by measuring the rates of absorption of ingested glucose and the clearance rate of glucose using tracer methods. These methods are based on labeling a 100-g oral glucose load with (1-/sup 14/C)glucose and measuring glucose clearance using plasma levels of infused (3-/sup 3/H)glucose. The rate of appearance of both ingested and total glucose is then calculated continuously using a two-compartment model of glucose kinetics. It was found that about 30% of the ingested glucose (100 g) failed to appear in the systemic circulation. That this was due to malabsorption was confirmed using breath-hydrogen analysis. The absorption period is short (101 +/- 11 min) compared with normal values but the clearance of glucose is identical to that in control subjects, and it peaks 132 +/- 7 min after glucose loading. The peak plasma insulin values were more than four times higher in patients than in normal subjects, and this may afford an explanation of rates of glucose clearance that are inappropriate for the short absorption period. The combination of glucose malabsorption and this clearance pattern could yield the hypoglycemia that may be observed in patients after gastric surgery.

  19. Heating from free-free absorption and the mass-loss rate of the progenitor stars to supernovae

    SciTech Connect

    Björnsson, C.-I.; Lundqvist, P. E-mail: peter@astro.su.se

    2014-06-01

    An accurate determination of the mass-loss rate of the progenitor stars to core-collapse supernovae is often limited by uncertainties pertaining to various model assumptions. It is shown that under conditions when the temperature of the circumstellar medium is set by heating due to free-free absorption, observations of the accompanying free-free optical depth allow a direct determination of the mass-loss rate from observed quantities in a rather model-independent way. The temperature is determined self-consistently, which results in a characteristic time dependence of the free-free optical depth. This can be used to distinguish free-free heating from other heating mechanisms. Since the importance of free-free heating is quite model dependent, this also makes possible several consistency checks of the deduced mass-loss rate. It is argued that the free-free absorption observed in SN 1993J is consistent with heating from free-free absorption. The deduced mass-loss rate of the progenitor star is, approximately, 10{sup –5} M {sub ☉} yr{sup –1} for a wind velocity of 10 km s{sup –1}.

  20. AUGMENTATION OF SULFATE ION ABSORPTION FROM THE RATE LUNG BY HEAVY METALS

    EPA Science Inventory

    The effect of heavy metal cations in enhancing the absorption of sulfate ions from the airways of the rat lung was studied. The cations investigated included Cd(2+), Co(2+), Hg(2+), Ni(2+), Fe(3+), Mn(2+), and Zn(2+). The cations exhibited differing efficacies. Co(2+), Hg(2+), Cd...

  1. Application of postured human model for SAR measurements

    NASA Astrophysics Data System (ADS)

    Vuchkovikj, M.; Munteanu, I.; Weiland, T.

    2013-07-01

    In the last two decades, the increasing number of electronic devices used in day-to-day life led to a growing interest in the study of the electromagnetic field interaction with biological tissues. The design of medical devices and wireless communication devices such as mobile phones benefits a lot from the bio-electromagnetic simulations in which digital human models are used. The digital human models currently available have an upright position which limits the research activities in realistic scenarios, where postured human bodies must be considered. For this reason, a software application called "BodyFlex for CST STUDIO SUITE" was developed. In its current version, this application can deform the voxel-based human model named HUGO (Dipp GmbH, 2010) to allow the generation of common postures that people use in normal life, ensuring the continuity of tissues and conserving the mass to an acceptable level. This paper describes the enhancement of the "BodyFlex" application, which is related to the movements of the forearm and the wrist of a digital human model. One of the electromagnetic applications in which the forearm and the wrist movement of a voxel based human model has a significant meaning is the measurement of the specific absorption rate (SAR) when a model is exposed to a radio frequency electromagnetic field produced by a mobile phone. Current SAR measurements of the exposure from mobile phones are performed with the SAM (Specific Anthropomorphic Mannequin) phantom which is filled with a dispersive but homogeneous material. We are interested what happens with the SAR values if a realistic inhomogeneous human model is used. To this aim, two human models, a homogeneous and an inhomogeneous one, in two simulation scenarios are used, in order to examine and observe the differences in the results for the SAR values.

  2. An RF dosimeter for independent SAR measurement in MRI scanners

    PubMed Central

    Qian, Di; El-Sharkawy, AbdEl-Monem M.; Bottomley, Paul A.; Edelstein, William A.

    2013-01-01

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B1) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average

  3. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect

    Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.; Edelstein, William A.

    2013-12-15

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on

  4. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    NASA Technical Reports Server (NTRS)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  5. CRUCIAL: Cryosat-2 Success over Inland Water and Land: Analyses and Validation of SAR and SARin Full Bit Rate Altimetric Heights

    NASA Astrophysics Data System (ADS)

    Moore, Philip; Benveniste, Jérôme; Birkinshaw, Stephen; Ambrózio, Américo; Restano, Marco

    2016-07-01

    CRUCIAL is an ESA/STSE funded project investigating innovative land and inland water applications from Cryosat-2 with a forward-look component to the future Sentinel-3 and Jason-CS/Sentinel-6 missions. The high along-track sampling of Cryosat-2 in its SAR and SARin modes offer the opportunity to recover high frequency signals over inland waters. A theoretical approach has been developed to process the FBR L1A Doppler beams to form a product using ground cell gridding, beam steering and beam stacking from which inland water heights are derivable from the retracked Cryosat-2 altimetric waveforms. Results of the processing strategy will include a comparison of waveforms and heights from the burst echoes (˜80 m along-track) and from multi-look waveforms (˜320 m along-track). SAR and SARin FBR data are available for the Amazon, Brahmaputra and Mekong for 2011-2015. FBR SAR results will be compared against stage data from the nearest gauge where applicable with heights from Tonle Sap compared against Jason-2 data from the United States Department of Agriculture. A strategy to select the number of multi-looks over rivers will also be presented. Results of FBR SARin processing for the Amazon and Brahmaputra will be presented including comparison of heights from the two antennae, extraction of slope of the ground surface and validation against ground data where appropriate.

  6. Evaluation of different partial AUCs as indirect measures of rate of drug absorption in comparative pharmacokinetic studies.

    PubMed

    Duquesnoy, C; Lacey, L F; Keene, O N; Bye, A

    1998-10-01

    The performance of different partial AUCs, including partial AUC from zero to t(max) of the reference formulation (AUC(r)) and partial AUC from zero to tmax of test or reference formulation, whichever occurs earliest (AUC(e), as indirect measures of rate of absorption have been evaluated using simulated experiments. The performance of these metrics relative to C(max), t(max) and C(max)/AUC(infinity) was further assessed using the results of actual studies involving a Glaxo drug. The normalised metrics AUC(r)/AUC(infinity) and AUC(e)/AUC(infinity) have also been evaluated. Our provisional conclusions were: (1) AUC(r)/AUC(infinity) and AUC(e)/AUC(infinity) had greater statistical power than C(max) and the non-normalised partial AUCs at detecting true differences in rate of absorption. Using real data, the performance of AUC(e)/AUC(infinity) was poor, however, the performance of AUC(r)/AUC(infinity) was good; (2) C(max)/AUC(infinity) was more precisely estimated than AUC(r)/AUC(infinity) or AUC(e)/AUC(infinity) and may be a superior metric for assessing absorption rates of highly variable drugs. PMID:9795077

  7. Studies in RF Power Communication, SAR, and Temperature Elevation in Wireless Implantable Neural Interfaces

    PubMed Central

    Zhao, Yujuan; Tang, Lin; Rennaker, Robert; Hutchens, Chris; Ibrahim, Tamer S.

    2013-01-01

    Implantable neural interfaces are designed to provide a high spatial and temporal precision control signal implementing high degree of freedom real-time prosthetic systems. The development of a Radio Frequency (RF) wireless neural interface has the potential to expand the number of applications as well as extend the robustness and longevity compared to wired neural interfaces. However, it is well known that RF signal is absorbed by the body and can result in tissue heating. In this work, numerical studies with analytical validations are performed to provide an assessment of power, heating and specific absorption rate (SAR) associated with the wireless RF transmitting within the human head. The receiving antenna on the neural interface is designed with different geometries and modeled at a range of implanted depths within the brain in order to estimate the maximum receiving power without violating SAR and tissue temperature elevation safety regulations. Based on the size of the designed antenna, sets of frequencies between 1 GHz to 4 GHz have been investigated. As expected the simulations demonstrate that longer receiving antennas (dipole) and lower working frequencies result in greater power availability prior to violating SAR regulations. For a 15 mm dipole antenna operating at 1.24 GHz on the surface of the brain, 730 uW of power could be harvested at the Federal Communications Commission (FCC) SAR violation limit. At approximately 5 cm inside the head, this same antenna would receive 190 uW of power prior to violating SAR regulations. Finally, the 3-D bio-heat simulation results show that for all evaluated antennas and frequency combinations we reach FCC SAR limits well before 1 °C. It is clear that powering neural interfaces via RF is possible, but ultra-low power circuit designs combined with advanced simulation will be required to develop a functional antenna that meets all system requirements. PMID:24223123

  8. A simplified method for calculating the atmospheric heating rate by absorption of solar radiation in the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, T.; Helmle, L. C.

    1979-01-01

    Calculations of the atmospheric heating rate by absorption of solar radiation by O3, H2O, and CO2 are reported. The method needs only seven parameters for each molecule and is particularly useful for heating calculations in three-dimensional global circulation models below 80 km. Applying the formula to the observed distributions of O3, H2O, and CO2 produces reasonable latitudinal and seasonal variations in the heating rate. The calculated heating rate, however, is sensitive to the global distributions of the absorbing gases, and uncertainties in the O3 distribution above approximately 50 km and the H2O distribution below approximately 20 km may seriously affect the global distributions of the heating rate in these regions.

  9. Modifying the high rate algal pond light environment and its effects on light absorption and photosynthesis.

    PubMed

    Sutherland, Donna L; Montemezzani, Valerio; Howard-Williams, Clive; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

    2015-03-01

    The combined use of high rate algal ponds (HRAPs) for wastewater treatment and commercial algal production is considered to be an economically viable option. However, microalgal photosynthesis and biomass productivity is constrained in HRAPs due to light limitation. This paper investigates how the light climate in the HRAP can be modified through changes in pond depth, hydraulic retention time (HRT) and light/dark turnover rate and how this impacts light absorption and utilisation by the microalgae. Wastewater treatment HRAPs were operated at three different pond depth and HRT during autumn. Light absorption by the microalgae was most affected by HRT, significantly decreasing with increasing HRT, due to increased internal self-shading. Photosynthetic performance (as defined by Pmax, Ek and α), significantly increased with increasing pond depth and decreasing HRT. Despite this, increasing pond depth and/or HRT, resulted in decreased pond light climate and overall integrated water column net oxygen production. However, increased light/dark turnover was able to compensate for this decrease, bringing the net oxygen production in line with shallower ponds operated at shorter HRT. On overcast days, modelled daily net photosynthesis significantly increased with increased light/dark turnover, however, on clear days such increased turnover did not enhance photosynthesis. This study has showed that light absorption and photosynthetic performance of wastewater microalgae can be modified through changes to pond depth, HRT and light/dark turnover. PMID:25514661

  10. Operation of a low temperature absorption chiller at rating point and at reduced evaporator temperature

    NASA Astrophysics Data System (ADS)

    Best, R.; Biermann, W.; Reimann, R. C.

    1985-01-01

    The returned fifteen ton Solar Absorption Machine (SAM) 015 chiller was given a cursory visual inspection, some obvious problems were remedied, and then it was placed on a test stand to get a measure of dirty performance. It was then given a standard acid clean, the water side of the tubes was brushed clean, and then the machine was retested. The before and after cleaning data were compared to equivalent data taken before the machine was shipped. The second part of the work statement was to experimentally demonstrate the technical feasibility of operating the chiller at evaporator temperatures below 0(0)C (32(0)F) and identify any operational problems.

  11. Effects of 2.45 GHz electromagnetic fields with a wide range of SARs on bacterial and HPRT gene mutations.

    PubMed

    Koyama, Shin; Takashima, Yoshio; Sakurai, Tomonori; Suzuki, Yukihisa; Taki, Masao; Miyakoshi, Junji

    2007-01-01

    Present day use of mobile phones is ubiquitous. This causes some concern for human health due to exposure to high-frequency electromagnetic fields (HFEMF) from mobile phones. Consequently, we have examined the effects of 2.45 GHz electromagnetic fields on bacterial mutations and the hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene mutations. Using the Ames test, bacteria were exposed to HFEMF for 30 min at specific absorption rates (SARs) from 5 to 200 W/kg. In all strains, there was no significant difference in the frequency of revertant colonies between sham exposure and HFEMF-exposed groups. In examination of mutations of the HPRT gene, Chinese hamster ovary (CHO)-K1 cells were exposed to HFEMF for 2 h at SARs from 5 to 200 W/kg. We detected a combination effect of simultaneous exposure to HFEMF and bleomycin at the respective SARs. A statistically significant difference was observed between the cells exposed to HFEMF at the SAR of 200 W/kg. Cells treated with the combination of HFEMF at SARs from 50 to 200 W/kg and bleomycin exhibited increased HPRT mutations. As the exposure to HFEMF induced an increase in temperature, these increases of mutation frequency may be a result of activation of bleomycin by heat. We consider that the increase of mutation frequency may be due to a thermal effect. PMID:17179647

  12. Analysis of the effect of mobile phone base station antenna loading on localized SAR and its consequences for measurements.

    PubMed

    Hansson, Björn; Thors, Björn; Törnevik, Christer

    2011-12-01

    In this work, the effect of antenna element loading on the localized specific absorption rate (SAR) has been analyzed for base station antennas. The analysis was conducted in order to determine whether localized SAR measurements of large multi-element base station antennas can be conducted using standardized procedures and commercially available equipment. More specifically, it was investigated if the antenna shifting measurement procedure, specified in the European base station exposure assessment standard EN 50383, will produce accurate localized SAR results for base station antennas larger than the specified measurement phantom. The obtained results show that SAR accuracy is affected by the presence of lossy material within distances of one wavelength from the tested antennas as a consequence of coupling and redistribution of transmitted power among the antenna elements. It was also found that the existing standardized phantom is not optimal for SAR measurements of large base station antennas. A new methodology is instead proposed based on a larger, box-shaped, whole-body phantom. PMID:21647933

  13. The estimation of 3D SAR distributions in the human head from mobile phone compliance testing data for epidemiological studies

    NASA Astrophysics Data System (ADS)

    Wake, Kanako; Varsier, Nadège; Watanabe, Soichi; Taki, Masao; Wiart, Joe; Mann, Simon; Deltour, Isabelle; Cardis, Elisabeth

    2009-10-01

    A worldwide epidemiological study called 'INTERPHONE' has been conducted to estimate the hypothetical relationship between brain tumors and mobile phone use. In this study, we proposed a method to estimate 3D distribution of the specific absorption rate (SAR) in the human head due to mobile phone use to provide the exposure gradient for epidemiological studies. 3D SAR distributions due to exposure to an electromagnetic field from mobile phones are estimated from mobile phone compliance testing data for actual devices. The data for compliance testing are measured only on the surface in the region near the device and in a small 3D region around the maximum on the surface in a homogeneous phantom with a specific shape. The method includes an interpolation/extrapolation and a head shape conversion. With the interpolation/extrapolation, SAR distributions in the whole head are estimated from the limited measured data. 3D SAR distributions in the numerical head models, where the tumor location is identified in the epidemiological studies, are obtained from measured SAR data with the head shape conversion by projection. Validation of the proposed method was performed experimentally and numerically. It was confirmed that the proposed method provided good estimation of 3D SAR distribution in the head, especially in the brain, which is the tissue of major interest in epidemiological studies. We conclude that it is possible to estimate 3D SAR distributions in a realistic head model from the data obtained by compliance testing measurements to provide a measure for the exposure gradient in specific locations of the brain for the purpose of exposure assessment in epidemiological studies. The proposed method has been used in several studies in the INTERPHONE.

  14. Some present problems and a proposed experimental phantom for SAR compliance testing of cellular telephones at 835 and 1900 MHz

    NASA Astrophysics Data System (ADS)

    Gandhi, Om P.; Kang, Gang

    2002-05-01

    This paper compares the maximum allowable powers of some typical cellular telephones at 835 and 1900 MHz for compliance with the limits of specific absorption rates (SAR) given in ANSI/IEEE, ICNIRP and the proposed modification of ANSI/IEEE safety guidelines. It is shown that the present ANSI/IEEE guideline is the most conservative with the ICNIRP guidelines allowing a maximum radiated power that is 2.5-3 times higher, and the proposed IEEE modification of treating pinna as an extremity tissue the least conservative allowing even higher radiated powers by up to 50%. The paper also expands the previously reported study of energy deposition in models of adults versus children to two different and distinct anatomically-based models of the adult head, namely the Utah model and the 'Visible Man' model, each of which is increased or reduced by the voxel size to obtain additional head models larger or smaller in all dimensions by 11.1% or -9.1%, respectively. The peak 1 g body-tissue SAR calculated using the widely accepted FDTD method for smaller models is up to 56% higher at 1900 MHz and up to 20% higher at 835 MHz compared to the larger models, with the average models giving intermediate SARs. Also given in the paper is a comparison of the peak 1 g and 10 g SARs for two different anatomically-based models with 6 mm thick smooth plastic ear models used for SAR compliance testing. The SARs obtained with the insulating plastic ear models are up to two or more times smaller than realistic anatomic models. We propose a 2 mm thin shell phantom with lossy ear that should give SARs within +/-15% of those of anatomic models.

  15. Variable food absorption by Antarctic krill: Relationships between diet, egestion rate and the composition and sinking rates of their fecal pellets

    NASA Astrophysics Data System (ADS)

    Atkinson, A.; Schmidt, K.; Fielding, S.; Kawaguchi, S.; Geissler, P. A.

    2012-01-01

    The kinetics of food processing by zooplankton affects both their energy budgets and the biogeochemical fate of their fecal pellets. We sampled 40 schools of krill across the Scotia Sea during spring, summer and autumn and found that in all 3 seasons, every aspect of their absorption and defecation varied greatly. The C content of fecal pellets varied from 0.85% to 29% of their dry mass (median 9.8%) and C egestion rates varied 75-fold. C:N mass ratios of pellets ranged from 4.9 to 13.2 (median 7.8), higher than values of 3.9 in the krill and 5.4 in their food, pointing to enhanced uptake of N. Pellet sinking rates equated to 27-1218 m d -1 (median 304 m d -1), being governed mainly by pellet diameter (80-600 μm, mean 183 μm) and density (1.038-1.391 g cm -3, mean 1.121 g cm -3). Pellets showed little loss of C or N in filtered seawater over the first 2 days and were physically robust. When feeding rates were low, slow gut passage time and high absorption efficiency resulted in low egestion rates of pellets that were low in C and N content. These pellets were compact, dense and fast-sinking. Conversely, in good feeding conditions much food tended to pass quickly through the gut and was not efficiently absorbed, producing C and N-rich, slow-sinking pellets. Such "superfluous feeding" probably maximises the absolute rates of nutrient absorption. Food composition was also important: diatom-rich diets depressed the C content of the pellets but increased their sinking rates, likely due to silica ballasting. So depending on how krill process food, their pellets could represent both vehicles for rapid export and slow sinking, C and N-rich food sources for pelagic scavengers. C egestion rates by krill averaged 3.4% of summer primary production (and ingestion rates would be 2-10-fold higher than this) so whatever the fate of the pellets, krill are an important re-packager within the food web. While salp pellets tend to sink faster than those of krill, it is the latter

  16. A method for the quantitative evaluation of SAR distribution in deep regional hyperthermia.

    PubMed

    Baroni, C; Giri, M G; Meliadó, G; Maluta, S; Chierego, G

    2001-01-01

    The Specific Absorption Rate (SAR) distribution pattern visualization by a matrix of E-field light-emitting sensors has demonstrated to be a useful tool to evaluate the characteristics of the applicators used in deep regional hyperthermia and to perform a quality assurance programme. A method to quantify the SAR from photographs of the sensor array--the so-called 'Power Stepping Technique'--has already been proposed. This paper presents a new approach to the quantitative determination of the SAR profiles in a liquid phantom exposed to electromagnetic fields from the Sigma-60 applicator (BSD-2000 system for deep regional hyperthermia). The method is based on the construction of a 'calibration curve' modelling the light-output of an E-field sensor as a function of the supplied voltage and on the use of a reference light source to 'normalize' the light-output readings from the photos of the sensor array, in order to minimize the errors introduced by the non-uniformity of the photographic process. Once the calibration curve is obtained, it is possible, with only one photo, to obtain the quantitative SAR distribution in the operating conditions. For this reason, this method is suitable for equipment characterization and also for the control of the repeatability of power deposition in time. PMID:11587076

  17. SAR pattern perturbations from resonance effects in water bolus layers used with superficial microwave hyperthermia applicators.

    PubMed

    Neuman, D G; Stauffer, P R; Jacobsen, S; Rossetto, F

    2002-01-01

    This study examines the effect of various thickness water bolus coupling layers on the SAR (Specific Absorption Rate) patterns from Dual Concentric Conductor (DCC) based Conformal Microwave Array (CMA) superficial hyperthermia applicators. Previous theory has suggested that water bolus coupling layers can be considered as a dielectric resonator; therefore, it is possible for the impinging electric field to stimulate volume oscillations and surface wave oscillations inside the water bolus. These spurious oscillations will destructively or constructively interact with the impinging electric field to cause a perturbation of the applicator SAR pattern. An experiment was designed which consisted of mapping the electric field produced by a four element DCC CMA applicator in liquid muscle phantom at depths of 5 and 10mm in front of four different thickness water boli; 0 (no bolus) 4, 9 and 13mm. Using the Finite Difference Time Domain (FDTD) method, SAR distributions were calculated for similar test cases. It was found that for water bolus thicknesses of 9mm or greater, there is a marked perturbation of both experimental and theoretical SAR distributions. It is believed that this perturbation is experimental confirmation of the volume and surface wave oscillation theory described by previous investigators. PMID:12028636

  18. Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

    NASA Astrophysics Data System (ADS)

    Zhu, Wu; Ding, Xiao-Li; Jung, Hyung-Sup; Zhang, Qin; Zhang, Bo-Chen; Qu, Wei

    2016-08-01

    Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect.

  19. New model for assessing dose, dose rate, and temperature sensitivity of radiation-induced absorption in glasses

    SciTech Connect

    Gilard, Olivier; Quadri, Gianandrea; Caussanel, Matthieu; Duval, Herve; Reynaud, Francois

    2010-11-15

    A new theoretical approach is proposed to explain the dose, dose rate and temperature sensitivity of the radiation-induced absorption (RIA) in glasses. In this paper, a {beta}{sup th}-order dispersive kinetic model is used to simulate the growth of the density of color centers in irradiated glasses. This model yields an explanation for the power-law dependence on dose and dose rate usually observed for the RIA in optical fibers. It also leads to an Arrhenius-like relationship between the RIA and the glass temperature during irradiation. With a very limited number of adjustable parameters, the model succeeds in explaining, with a good agreement, the RIA growth of two different optical fiber references over wide ranges of dose, dose rate and temperature.

  20. Advanced digital SAR processing study

    NASA Technical Reports Server (NTRS)

    Martinson, L. W.; Gaffney, B. P.; Liu, B.; Perry, R. P.; Ruvin, A.

    1982-01-01

    A highly programmable, land based, real time synthetic aperture radar (SAR) processor requiring a processed pixel rate of 2.75 MHz or more in a four look system was designed. Variations in range and azimuth compression, number of looks, range swath, range migration and SR mode were specified. Alternative range and azimuth processing algorithms were examined in conjunction with projected integrated circuit, digital architecture, and software technologies. The advaced digital SAR processor (ADSP) employs an FFT convolver algorithm for both range and azimuth processing in a parallel architecture configuration. Algorithm performace comparisons, design system design, implementation tradeoffs and the results of a supporting survey of integrated circuit and digital architecture technologies are reported. Cost tradeoffs and projections with alternate implementation plans are presented.

  1. Rate-equation model for quantitative concentration measurements in flames with picosecond pump-probe absorption spectroscopy.

    PubMed

    Fiechtner, G J; King, G B; Laurendeau, N M

    1995-02-20

    Measurement of radical concentrations is important in understanding the chemical kinetics involved in combustion. Application of optical techniques allows for the nonintrusive determination of specific radical concentrations. One of the most challenging problems for investigators is to obtain flame data that are independent of the collisional environment. We seek to obviate this difficulty by the use of picosecond pump-probe absorption spectroscopy. A picosecond pump-probe absorption model is developed by rate-equation analysis. Implications are discussed for a laser-pulse width that is much smaller than the excited-state lifetime of the absorbing atom or molecule. The possibility of quantitative, quenching-independent concentration measurements is discussed, and detection limits for atomic sodium and the hydroxyl radical are estimated. For a three-level absorber-emitter, the model leads to a novel pump-probe strategy, called dual-beam asynchronous optical sampling, that can be used to obtain both the electronic quenching-rate coefficient and the doublet mixing-rate coefficient during a single measurement. We discuss the successful demonstration of the technique in a companion paper [Appl. Opt. 34, XXX (1995)]. PMID:21037640

  2. Transient finite element analysis of thermal methods used to estimate SAR and blood flow in homogeneously and nonhomogeneously perfused tumour models.

    PubMed

    Wong, T Z; Mechling, J A; Jones, E L; Strohbehn, J W

    1988-01-01

    A two-dimensional time-dependent finite element model was developed to evaluate thermal techniques for estimating blood flow and specific absorption rate (SAR). In these computer simulations, homogeneously and nonhomogeneously perfused tumour models were heated by a 915 MHz interstitial microwave antenna array. Representative blood flow values were assigned within the tumour, and the applied SAR distribution was based on a previously developed antenna theory. SAR values were estimated from the power-on transient temperatures, and blood flow values were estimated from thermal clearance data after power was discontinued. These estimated parameters were then compared to the known 'true' blood flow and SAR values throughout the treatment region. SAR values could be predicted with reasonable accuracy throughout most of the heated region independent of local blood flow. For a homogeneous model, thermal clearance was found to yield reasonably accurate blood flow estimates at high perfusion rates and less accurate estimates at lower perfusion rates. However, for the inhomogeneous model, the blood perfusion estimates were generally poor, and an average blood flow value for the tumour was obtained with little ability to resolve the differences in perfusion between regions. Using temperatures observed early in the cool-down curve resulted in improved spatial resolution, but increased the contribution of thermal conduction to the blood flow estimates. A single time-constant exponential thermal decay curve was found to be a necessary but not sufficient condition for reliable blood flow estimates using this technique. PMID:3171254

  3. Generalized energy-aperture product limit for multi-beam and spotlight SARs

    SciTech Connect

    Karr, T.J.

    1995-12-21

    The SAR energy-aperture product limit is extended to multi-beam SARS, Spotlight and moving spotlight SARS. This fundamental limit bounds the tradeoff between energy and antenna size. The kinematic relations between design variables such as platform speed, pulse repetition frequency, beam width and area rate are analyzed in a unified framework applicable to a wide variety of SARs including strip maps, spotlights, vermer arrays and multi-beam SARS, both scanning and swept-beam. Then the energy-aperture product limit is derived from the signal-to noise requirement and the kinematic constraints. The derivation clarifies impact of multiple beams and spotlighting on SAR performance.

  4. A fast, programmable hardware architecture for spaceborne SAR processing

    NASA Technical Reports Server (NTRS)

    Bennett, J. R.; Cumming, I. G.; Lim, J.; Wedding, R. M.

    1983-01-01

    The launch of spaceborne SARs during the 1980's is discussed. The satellite SARs require high quality and high throughput ground processors. Compression ratios in range and azimuth of greater than 500 and 150 respectively lead to frequency domain processing and data computation rates in excess of 2000 million real operations per second for C-band SARs under consideration. Various hardware architectures are examined and two promising candidates and proceeds to recommend a fast, programmable hardware architecture for spaceborne SAR processing are selected. Modularity and programmability are introduced as desirable attributes for the purpose of HTSP hardware selection.

  5. Quantitative validation of the 3D SAR profile of hyperthermia applicators using the gamma method.

    PubMed

    de Bruijne, Maarten; Samaras, Theodoros; Chavannes, Nicolas; van Rhoon, Gerard C

    2007-06-01

    For quality assurance of hyperthermia treatment planning systems, quantitative validation of the electromagnetic model of an applicator is essential. The objective of this study was to validate a finite-difference time-domain (FDTD) model implementation of the Lucite cone applicator (LCA) for superficial hyperthermia. The validation involved (i) the assessment of the match between the predicted and measured 3D specific absorption rate (SAR) distribution, and (ii) the assessment of the ratio between model power and real-world power. The 3D SAR distribution of seven LCAs was scanned in a phantom bath using the DASY4 dosimetric measurement system. The same set-up was modelled in SEMCAD X. The match between the predicted and the measured SAR distribution was quantified with the gamma method, which combines distance-to-agreement and dose difference criteria. Good quantitative agreement was observed: more than 95% of the measurement points met the acceptance criteria 2 mm/2% for all applicators. The ratio between measured and predicted power absorption ranged from 0.75 to 0.92 (mean 0.85). This study shows that quantitative validation of hyperthermia applicator models is feasible and is worth considering as a part of hyperthermia quality assurance procedures. PMID:17505090

  6. High Repetition Rate and Frequency Stabilized Ho:YLF Laser for CO2 Differential Absorption Lidar

    NASA Technical Reports Server (NTRS)

    Bai, Yingxin; Yu, Jirong; Petros, M.; Petzar, Pau; Trieu, Bo; Lee, Hyung; Singh, U.

    2009-01-01

    High repetition rate operation of an injection seeded Ho:YLF laser has been demonstrated. For 1 kHz operation, the output pulse energy reaches 5.8mJ and the optical-to-optical efficiency is 39% when the pump power is 14.5W.

  7. Absorbed Dose Rates in Tissue from Prompt Gamma Emissions from Near-thermal Neutron Absorption.

    PubMed

    Schwahn, Scott O

    2015-10-01

    Prompt gamma emission data from the International Atomic Energy Agency's Prompt Gamma-ray Neutron Activation Analysis database are analyzed to determine the absorbed dose rates in tissue to be expected when natural elements are exposed in a near-thermal neutron environment. PMID:26313590

  8. Absorbed dose rates in tissue from prompt gamma emissions from near-thermal neutron absorption

    DOE PAGESBeta

    Schwahn, Scott O.

    2015-10-01

    Prompt gamma emission data from the International Atomic Energy Agency s Prompt Gamma-ray Neutron Activation Analysis database are analyzed to determine the absorbed dose rates in tissue to be expected when natural elements are exposed in a near-thermal neutron environment.

  9. Absorption of microwave radiation by the anesthetized rat: electromagnetic and thermal hotspots in body and tail

    SciTech Connect

    D'Andrea, J.A.; Emmerson, R.Y.; DeWitt, J.R.; Gandhi, O.P.

    1987-01-01

    Anatomic variability in the deposition of radiofrequency electromagnetic energy in mammals has been well documented. A recent study reported specific absorption rate (SAR) hotspots in the brain, rectum and tail of rat carcasses exposed to 360- and to 2450-MHz microwave radiation. Regions of intense energy absorption are generally thought to be of little consequence when predicting thermal effects of microwave irradiation because it is presumed that heat transfer via the circulatory system promptly redistributes localized heat to equilibrate tissue temperature within the body. Experiments on anesthetized, male Long-Evans rats (200-260 g) irradiated for 10 or 16 min with 2450, 700, or 360 MHz radiation at SARs of 2 W/kg, 6 W/kg, or 10 W/kg indicated that postirradiation localized temperatures in regions previously shown to exhibit high SARs were appreciably above temperatures at body sites with lower SARs. The postirradiation temperatures in the rectum and tail were significantly higher in rats irradiated at 360 MHz and higher in the tail at 2450 MHz than temperatures resulting from exposure to 700 MHz. This effect was found for whole-body-averaged SARs as low as 6 W/kg at 360 MHz and 10 W/kg at 2450 MHz. In contrast, brain temperatures in the anesthetized rats were not different from those measured in the rest of the body following microwave exposure.

  10. Enhancement of specific absorption rate by exchange coupling of the core-shell structure of magnetic nanoparticles for magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Phadatare, M. R.; Meshram, J. V.; Gurav, K. V.; Hyeok Kim, Jin; Pawar, S. H.

    2016-03-01

    Conversion of electromagnetic energy into heat by nanoparticles (NPs) has the potential to be a powerful, non-invasive technique for biomedical applications such as magnetic fluid hyperthermia, drug release, disease treatment and remote control of single cell functions, but poor conversion efficiencies have hindered practical applications so far. In this paper, an attempt has been made to increase the efficiency of magnetic thermal induction by NPs. To increase the efficiency of magnetic thermal induction by NPs, one can take advantage of the exchange coupling between a magnetically hard core and magnetically soft shell to tune the magnetic properties of the NP and maximize the specific absorption rate, which is the gauge of conversion efficiency. In order to examine the tunability of magnetocrystalline anisotropy and its magnetic heating power, a representative magnetically hard material (CoFe2O4) has been coupled to a soft material (Ni0.5Zn0.5Fe2O4). The synthesized NPs show specific absorption rates that are of an order of magnitude larger than the conventional one.

  11. Rate and composition control by atomic absorption spectroscopy for the coevaporation of high T sub c superconducting films

    SciTech Connect

    Lu, C. ); Missert, N.; Mooij, J.E.; Rosenthal, P.; Matijasevic, V.; Beasley, M.R.; Hammond, R.H. )

    1989-02-01

    Atomic absorption spectroscopy has been used to control the deposition rates during coevaporation processes with multiple electron-beam sources. This technique is material specific and thus allows the deposition rate of each component to be controlled independently. Because only a light beam is needed to interact with the vapor stream, the sampling region can be selected to be very close to the substrate for precise control of the film composition. With its high sensitivity and no limitations on operation pressure, this technique offers some unique advantages for the preparation of high Tc superconducting films by coevaporation in a high oxygen partial pressure environment. The performance of a multi-source deposition controller and the resultant film properties are presented.

  12. SAR antenna calibration techniques

    NASA Technical Reports Server (NTRS)

    Carver, K. R.; Newell, A. C.

    1978-01-01

    Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach.

  13. Real-time SAR change-detection using neural networks

    NASA Astrophysics Data System (ADS)

    Oliver, Christopher J.; White, Richard G.

    1990-11-01

    This paper describes the techniques evolved at RSRE for the production of undistorted, focused synthetic aperture radar (SAR) images, target detection using a neural network method and the automatic detection of changes between pairs of SAR images. All these processes are achievable in a single pipelined process operating on an input data rate in excess of 10 Mbytes/second.

  14. Heating rates in furnace atomic absorption using the L'vov platform

    USGS Publications Warehouse

    Koirtyohann, S.R.; Giddings, R.C.; Taylor, H.E.

    1984-01-01

    Heating rate profiles for the furnace tube wall, the furnace atmosphere, and a L'vov platform were established for a range of conditions in a cyclically heated graphite atomizer. The tube wall profile was made by direct observation with a recording optical pyrometer. The sodium line reversal method was used to establish the heating rate of the furnace atmosphere, and appearance temperatures for a series metals of differing volatility was used to establish platform profiles. The tube wall heating rate was nearly linear at 2240??C s- until the desired temperature was reached after which the temperature remained constant. The furnace atmosphere reached a given temperature 0.2-0.4 s later than the tube wall through most of the atomize cycle. The platform lagged the tube wall 0.5-0.8 s. Under typical operating conditions the furnace atmosphere was 100-200??C cooler than the tube wall and at nearly constant temperature when the analyte vaporized from the platform. The L'vov platform causes the cyclically heated commercial furnace to approximate the behavior of a constant temperature furnace during atomization. ?? 1984.

  15. Aqueous suspensions of polymer coated magnetite nanoparticles: Colloidal stability, specific absorption rate, and transverse relaxivity

    NASA Astrophysics Data System (ADS)

    Saville, Steven Lee

    The design, functionalization, characterization, and applications of magnetic nanoparticles have garnered significant interest over the past several decades. While this area has garnered increasing attention, several questions remain unanswered about the stability of these systems and it's influence on their biomedical applications. To help answer these questions about the stability of these, a novel tri(nitroDOPA) terminated polymer based ligand has been developed for the stabilization of magnetite nanoparticles. The synthesis involves a process in which ethylene oxide is polymerized using a trivinyl initiator, modified with carboxylic acid using a free radical addition of mercaptoundecanoic acid, and then functionalized with nitroDOPA using N,N-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) chemistry. This polymer has displayed robust adhesion even in harsh chemical environments, out performing many polymers used today for the stabilization of magnetite. Along these same lines, the effects of instability of these systems were analyzed in both MRI and magnetic hyperthermia applications. It is widely known that formation of linear aggregates (i.e. chains) occurs in more concentrated ferrofluids systems and that this has an affect on the ferrofluid properties. It has been recently reported that for some suspensions of magnetic nanoparticles the transverse proton relaxation rate, R2, is dependent on the time that the sample is exposed to an applied magnetic field. This time dependence has been linked to the formation of linear aggregates or chains in an applied magnetic field via numerical modeling. In this work the relationships between colloidal stability, the formation of these linear structures, and changes observed in the proton transverse relaxation rate and heating rate in magnetic hyperthermia of aqueous suspensions of magnetic particles are examined. The results indicate that varying the ligand length has a direct effect on the colloidal

  16. SAR calibration technology review

    NASA Technical Reports Server (NTRS)

    Walker, J. L.; Larson, R. W.

    1981-01-01

    Synthetic Aperture Radar (SAR) calibration technology including a general description of the primary calibration techniques and some of the factors which affect the performance of calibrated SAR systems are reviewed. The use of reference reflectors for measurement of the total system transfer function along with an on-board calibration signal generator for monitoring the temporal variations of the receiver to processor output is a practical approach for SAR calibration. However, preliminary error analysis and previous experimental measurements indicate that reflectivity measurement accuracies of better than 3 dB will be difficult to achieve. This is not adequate for many applications and, therefore, improved end-to-end SAR calibration techniques are required.

  17. Energy transfer among CP29 chlorophylls: calculated Förster rates and experimental transient absorption at room temperature.

    PubMed

    Cinque, G; Croce, R; Holzwarth, A; Bassi, R

    2000-10-01

    The energy transfer rates between chlorophylls in the light harvesting complex CP29 of higher plants at room temperature were calculated ab initio according to the Förster mechanism (Förster T. 1948, Ann. Physik. 2:55-67). Recently, the transition moment orientation of CP29 chlorophylls was determined by differential linear dichroism and absorption spectroscopy of wild-type versus mutant proteins in which single chromophores were missing (Simonetto R., Crimi M., Sandonà D., Croce R., Cinque G., Breton J., and Bassi R. 1999. Biochemistry. 38:12974-12983). In this way the Q(y) transition energy and chlorophyll a/b affinity of each binding site was obtained and their characteristics supported by reconstruction of steady-state linear dichroism and absorption spectra at room temperature. In this study, the spectral form of individual chlorophyll a and b ligands within the protein environment was experimentally determined, and their extinction coefficients were also used to evaluate the absolute overlap integral between donors and acceptors employing the Stepanov relation for both the emission spectrum and the Stokes shift. This information was used to calculate the time-dependent excitation redistribution among CP29 chlorophylls on solving numerically the Pauli master equation of the complex: transient absorption measurements in the (sub)picosecond time scale were simulated and compared to pump-and-probe experimental data in the Q(y) region on the native CP29 at room temperature upon selective excitation of chlorophylls b at 640 or 650 nm. The kinetic model indicates a bidirectional excitation transfer over all CP29 chlorophylls a species, which is particularly rapid between the pure sites A1-A2 and A4-A5. Chlorophylls b in mixed sites act mostly as energy donors for chlorophylls a, whereas site B5 shows high and bidirectional coupling independent of the pigment hosted. PMID:11023879

  18. Stepped heating procedure for experimental SAR evaluation of ferrofluids.

    PubMed

    Iacob, N; Schinteie, G; Palade, P; Ticos, C M; Kuncser, V

    2015-06-01

    The aim of this paper is to present a reliable procedure for the experimental determination of the specific absorption rate (SAR) in case of superparamagnetic Fe oxide nanoparticles dispersed in liquid environments. It is based on the acquisition of consecutive steps of time-temperature dependences along of both heating and cooling processes. Linear fitting of these recorded steps provides the heating and cooling speeds at different temperatures, which finally allow the determination of the heating profile in adiabatic-like conditions over a broad temperature range. The presented methodology represents on one hand, a useful alternative tool for the experimental evaluation of the heating capability of nanoparticulate systems for magnetic hyperthermia applications and on the other hand, gives support for a more accurate modeling of bio-heat transfer phenomena. PMID:26087918

  19. The absorption and metabolism of a single L-menthol oral versus skin administration: Effects on thermogenesis and metabolic rate.

    PubMed

    Valente, Angelica; Carrillo, Andres E; Tzatzarakis, Manolis N; Vakonaki, Elena; Tsatsakis, Aristidis M; Kenny, Glen P; Koutedakis, Yiannis; Jamurtas, Athanasios Z; Flouris, Andreas D

    2015-12-01

    We investigated the absorption and metabolism pharmacokinetics of a single L-menthol oral versus skin administration and the effects on human thermogenesis and metabolic rate. Twenty healthy adults were randomly distributed into oral (capsule) and skin (gel) groups and treated with 10 mg kg(-1) L-menthol (ORALMENT; SKINMENT) or control (lactose capsule: ORALCON; water application: SKINCON) in a random order on two different days. Levels of serum L-menthol increased similarly in ORALMENT and SKINMENT (p > 0.05). L-menthol glucuronidation was greater in ORALMENT than SKINMENT (p < 0.05). Cutaneous vasoconstriction, rectal temperature and body heat storage showed greater increase following SKINMENT compared to ORALMENT and control conditions (p < 0.05). Metabolic rate increased from baseline by 18% in SKINMENT and 10% in ORALMENT and respiratory exchange ratio decreased more in ORALMENT (5.4%) than SKINMENT (4.8%) compared to control conditions (p < 0.05). Levels of plasma adiponectin and leptin as well as heart rate variability were similar to control following either treatment (p > 0.05). Participants reported no cold, shivering, discomfort, stress or skin irritation. We conclude that a single L-menthol skin administration increased thermogenesis and metabolic rate in humans. These effects are minor following L-menthol oral administration probably due to faster glucuronidation and greater blood menthol glucuronide levels. PMID:26429629

  20. Feeding rates affect growth, intestinal digestive and absorptive capabilities and endocrine functions of juvenile blunt snout bream Megalobrama amblycephala.

    PubMed

    Xu, Chao; Li, Xiang-Fei; Tian, Hong-Yan; Jiang, Guang-Zhen; Liu, Wen-Bin

    2016-04-01

    This study aimed to investigate the optimal feeding rate for juvenile blunt snout bream (average initial weight 23.74 ± 0.09 g) based on the results on growth performance, intestinal digestive and absorptive capabilities and endocrine functions. A total of 840 fish were randomly distributed into 24 cages and fed a commercial feed at six feeding rates ranging from 2.0 to 7.0 % body weight (BW)/day. The results indicated that weight gain rate increased significantly (P < 0.05) as feeding rates increased from 2.0 to 5.0 % BW/day, but decreased with the further increasing feeding rates (P > 0.05). Protein efficiency ratio and nitrogen and energy retention all showed a similar trend. However, feed conversion ratio increased significantly (P < 0.05) with increasing feeding rates. Feeding rates have little effects (P > 0.05) on whole-body moisture, ash and protein contents, but significantly (P < 0.05) affect both lipid and energy contents with the highest values both observed in fish fed 4.0 % BW/day. In addition, moderate ration sizes (2.0-4.0 % BW/day) resulted in the enhanced activities of intestinal enzymes, including lipase, protease, Na(+), K(+)-ATPase, alkaline phosphatase and creatine kinase. Furthermore, the mRNA levels of growth hormone, insulin-like growth factors-I, growth hormone receptor and neuropeptide all increased significantly (P < 0.05) as feeding rates increased from 2.0 to 5.0 % and 6.0 % BW/day, but decreased significantly (P < 0.05) with the further increase in feeding rates, whereas both leptin and cholecystokinin expressions showed an opposite trend. Based on the broken-line regression analysis of SGR against feeding rates, the optimal feeding rate for juvenile blunt snout bream was estimated to be 4.57 % BW/day. PMID:26597852

  1. HCFC-133a (CF3CH2Cl): OH rate coefficient, UV and infrared absorption spectra, and atmospheric implications

    NASA Astrophysics Data System (ADS)

    McGillen, Max R.; Bernard, François; Fleming, Eric L.; Burkholder, James B.

    2015-07-01

    HCFC-133a (CF3CH2Cl), an ozone-depleting substance, is primarily removed from the atmosphere by gas-phase reaction with OH radicals and by UV photolysis. The rate coefficient, k, for the OH + HCFC-133a reaction was measured between 233 and 379 K and is given by k(T) = (9.32 ± 0.8) × 10-13 exp(-(1296 ± 28)/T), where k(296 K) was measured to be (1.10 ± 0.02) × 10-14 (cm3 molecule-1 s-1) (2σ precision uncertainty). The HCFC-133a UV absorption spectrum was measured between 184.95 and 240 nm at 213-323 K, and a spectrum parameterization is presented. The HCFC-133a atmospheric loss processes, lifetime, ozone depletion potential, and uncertainties were evaluated using a 2-D atmospheric model. The global annually averaged steady state lifetime and ozone depletion potential (ODP) were determined to be 4.45 (4.04-4.90) years and 0.017 (±0.001), respectively, where the ranges are based solely on the 2σ uncertainty in the kinetic and photochemical parameters. The infrared absorption spectrum of HCFC-133a was measured, and its global warming potential was determined to be 380 on the 100 year time horizon.

  2. EFFECT OF HEATING RATE ON EVAPORATIVE HEAT LOSS IN THE MICROWAVE-EXPOSED MOUSE

    EPA Science Inventory

    Male CBA/J mice were administered heat loads of 0-28 J. per g at specific absorption rates (SARs) of either 47 or 93 W. per kg by exposure to 2,450-MHz microwave radiation at an ambient temperature of 30 C while evaporative heat loss (EHL) was continuously monitored with dew-poin...

  3. Hydrogen capacity and absorption rate of the SAES St707 non-evaporable getter at various temperatures.

    SciTech Connect

    Hsu, Irving; Mills, Bernice E.

    2010-08-01

    A prototype of a tritium thermoelectric generator (TTG) is currently being developed at Sandia. In the TTG, a vacuum jacket reduces the amount of heat lost from the high temperature source via convection. However, outgassing presents challenges to maintaining a vacuum for many years. Getters are chemically active substances that scavenge residual gases in a vacuum system. In order to maintain the vacuum jacket at approximately 1.0 x 10{sup -4} torr for decades, nonevaporable getters that can operate from -55 C to 60 C are going to be used. This paper focuses on the hydrogen capacity and absorption rate of the St707{trademark} non-evaporable getter by SAES. Using a getter testing manifold, we have carried out experiments to test these characteristics of the getter over the temperature range of -77 C to 60 C. The results from this study can be used to size the getter appropriately.

  4. SARS/avian coronaviruses.

    PubMed

    Monceyron Jonassen, C

    2006-01-01

    In the hunt for the aetiology of the SARS outbreak in 2003, a newly developed virus DNA micro-array was successfully used to hybridise PCR products obtained by random amplification of nucleic acids extracted from a cell culture infected with material from a SARS patient. The SARS agent was found to hybridise with micro-array probes from both coronaviruses and astroviruses, but one of the coronavirus probes and the four astrovirus probes contained redundant sequences, spanning a highly conserved motif, named s2m, found at the 3' end of the genomes of almost all astroviruses, one picornavirus, and the poultry coronaviruses. The three other coronavirus probes, that hybridised with the SARS agent, were located in the replicase gene, and it could be concluded that the SARS agent was a novel coronavirus, harbouring s2m. The presence of this motif in different virus families is probably the result of recombinations between unrelated viruses, but its presence in both poultry and SARS coronaviruses could suggest a bird involvement in the history of the SARS coronavirus. A recent screening of wild birds for the presence of coronaviruses, using a pan-coronavirus RT-PCR, led to the identification of novel coronaviruses in the three species studied. Phylogenetic analyses performed on both replicase gene and nucleocapsid protein could not add support to a close relationship between avian and SARS coronaviruses, but all the novel avian coronaviruses were found to harbour s2m. The motif is inserted at a homologous place in avian and SARS coronavirus genomes, but in a somewhat different context for the SARS coronavirus. If the presence of s2m in these viruses is a result of two separate recombination events, this suggests that its particular position in these genomes is the only one that would not be deleterious for coronaviral replication, or that it is the result of a copy-choice recombination between coronaviruses, following an ancestral introduction in the coronavirus family by

  5. Development of a carbonate absorption-based process for post-combustion CO2 capture: The role of biocatalyst to promote CO2 absorption rate

    USGS Publications Warehouse

    Lu, Y.; Ye, X.; Zhang, Z.; Khodayari, A.; Djukadi, T.

    2011-01-01

    An Integrated Vacuum Carbonate Absorption Process (IVCAP) for post-combustion carbon dioxide (CO2) capture is described. IVCAP employs potassium carbonate (PC) as a solvent, uses waste or low quality steam from the power plant for CO2 stripping, and employs a biocatalyst, carbonic anhydrase (CA) enzyme, for promoting the CO2 absorption into PC solution. A series of experiments were performed to evaluate the activity of CA enzyme mixed in PC solutions in a stirred tank reactor system under various temperatures, CA dosages, CO2 loadings, CO2 partial pressures, and the presence of major flue gas contaminants. It was demonstrated that CA enzyme is an effective biocatalyst for CO2 absorption under IVCAP conditions. ?? 2011 Published by Elsevier Ltd.

  6. Ingestion of insoluble dietary fibre increased zinc and iron absorption and restored growth rate and zinc absorption suppressed by dietary phytate in rats.

    PubMed

    Hayashi, K; Hara, H; Asvarujanon, P; Aoyama, Y; Luangpituksa, P

    2001-10-01

    We examined the effects of ingestion of five types of insoluble fibre on growth and Zn absorption in rats fed a marginally Zn-deficient diet (6.75 mg (0.103 mmol) Zn/kg diet) with or without added sodium phytate (12.6 mmol/kg diet). The types of insoluble fibre tested were corn husks, watermelon skin, yam-bean root (Pachyrhizus erosus) and pineapple core, and cellulose was used as a control (100 g/kg diet). Body-weight gain in the cellulose groups was suppressed by 57 % by feeding phytate. Body-weight gain in phytate-fed rats was 80 % greater in the watermelon skin fibre and yam-bean root fibre group than that in the cellulose group. Zn absorption ratio in the cellulose groups was lowered by 46 and 70 % in the first (days 7-10) and second (days 16-19) measurement periods with feeding phytate. In the rats fed the phytate-containing diets, Zn absorption ratio in the watermelon skin, yam-bean root and pineapple core fibre groups was 140, 80 and 54 % higher respectively than that in the cellulose group, in the second period. Fe absorption was not suppressed by phytate, however, feeding of these three types of fibre promoted Fe absorption in rats fed phytate-free diets. The concentration of soluble Zn in the caecal contents in the watermelon skin fibre or yam-bean root fibre groups was identical to that in the control group in spite of a higher short-chain fatty acid concentration and lower pH in the caecum. These findings indicate that ingestion of these types of insoluble fibre recovered the growth and Zn absorption suppressed by feeding a high level of phytate, and factors other than caecal fermentation may also be involved in this effect of insoluble fibre. PMID:11591231

  7. A study in normal human volunteers to compare the rate and extent of levothyroxine absorption from Synthroid and Levoxine.

    PubMed

    Berg, J A; Mayor, G H

    1992-12-01

    Numerous branded and generic formulations of levothyroxine (LT4) sodium tablets are currently available. Results from previous studies attempting to examine the comparative bioavailability of these formulations are difficult to interpret because of subject heterogeneity, single time-point blood sampling, varying degrees of hypothyroidism, and other factors. This study was devised to compare the rate and extent of absorption of LT4 from different LT4 sodium tablet formulations, in a simple model using a single-dose two-way single-blind, randomized cross-over design in 30 normal, healthy, nonpregnant, female subjects. This design controlled for many factors that limited previous LT4 bioavailability studies. Subjects were given a single 600 micrograms dose of LT4 as either Synthroid (Boots Pharmaceuticals, Inc., Lincolnshire, IL) tablets (formulation A) or Levoxine tablets (Daniels Pharmaceuticals, St. Petersburg, FL; formulation B). Measurements of baseline-corrected total T4 serum concentrations determined at multiple time points demonstrated statistically significant differences between the two formulations at the 1.00, 3.00, 5.00, and 18.00 hour sampling times. Statistically significant differences for area under the curve (AUC) (0 to 48 hours) (formulation A, 159.9 +/- 9.4 micrograms-hour/dL; formulation B, 193.4 +/- 10.1 micrograms-hour/dL) and maximum peak plasma concentration (Cmax) (formulation A, 5.91 +/- .34; formulation B, 7.12 +/- .32) also were demonstrated. Furthermore, the ratio of the baseline-corrected total T4 concentrations (B/A x 100) were 120.9% for AUC and 120.5% for Cmax. These data demonstrate that the administration of Synthroid and Levoxine result in a significantly different rate and extent of absorption of LT4, and therefore these two formulations cannot be considered bioequivalent.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1487553

  8. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy

    NASA Astrophysics Data System (ADS)

    Shubitidze, Fridon; Kekalo, Katsiaryna; Stigliano, Robert; Baker, Ian

    2015-03-01

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2-5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20-40 nm flower-like aggregates with a hydrodynamic diameter of 110-120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99-164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (<250 Oe). This may extend MNP hyperthermia therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue.

  9. Magnetic nanoparticles with high specific absorption rate of electromagnetic energy at low field strength for hyperthermia therapy

    PubMed Central

    Stigliano, Robert; Baker, Ian

    2015-01-01

    Magnetic nanoparticles (MNPs), referred to as the Dartmouth MNPs, which exhibit high specific absorption rate at low applied field strength have been developed for hyperthermia therapy applications. The MNPs consist of small (2–5 nm) single crystals of gamma-Fe2O3 with saccharide chains implanted in their crystalline structure, forming 20–40 nm flower-like aggregates with a hydrodynamic diameter of 110–120 nm. The MNPs form stable (>12 months) colloidal solutions in water and exhibit no hysteresis under an applied quasistatic magnetic field, and produce a significant amount of heat at field strengths as low as 100 Oe at 99–164 kHz. The MNP heating mechanisms under an alternating magnetic field (AMF) are discussed and analyzed quantitatively based on (a) the calculated multi-scale MNP interactions obtained using a three dimensional numerical model called the method of auxiliary sources, (b) measured MNP frequency spectra, and (c) quantified MNP friction losses based on magneto-viscous theory. The frequency responses and hysteresis curves of the Dartmouth MNPs are measured and compared to the modeled data. The specific absorption rate of the particles is measured at various AMF strengths and frequencies, and compared to commercially available MNPs. The comparisons demonstrate the superior heating properties of the Dartmouth MNPs at low field strengths (<250 Oe). This may extend MNP hyperthermia therapy to deeper tumors that were previously non-viable targets, potentially enabling the treatment of some of the most difficult cancers, such as pancreatic and rectal cancers, without damaging normal tissue. PMID:25825545

  10. SAR Simulation with Magneto Chiral Effects for Human Head Radiated from Cellular Phones

    NASA Astrophysics Data System (ADS)

    Torres-Silva, H.

    2008-09-01

    A numerical method for a microwave signal emitted by a cellular phone, propagating in a magneto-chiral media, characterized by an extended Born-Fedorov formalism, is presented. It is shown that the use of a cell model, combined with a real model of the human head, derived from the magnetic resonance of images allows a good determination of the near fields induced in the head when the brain chirality and the battery magnetic field are considered together. The results on a 2-Dim human head model show the evolution of the specific absorption rate, (SAR coefficient) and the spatial peak specific absorption rate which are sensitives to the magneto-chiral factor, which is important in the brain layer. For GSM/PCN phones, extremely low frequency real pulsed magnetic fields (in the order of 10 to 60 milligauss) are added to the model through the whole of the user's head. The more important conclusion of our work is that the head absorption is bigger than the results for a classical model without the magneto chiral effect. Hot spots are produced due to the combination of microwave and the magnetic field produced by the phone's operation. The FDTD method was used to compute the SARs inside the MRI based head models consisting of various tissues for 1.8 GHz. As a result, we found that in the head model having more than four kinds of tissue, the localized peak SAR reaches maximum inside the head for over five tissues including skin, bone, blood and brain cells.

  11. The influence of colloidal parameters on the specific power absorption of PAA-coated magnetite nanoparticles

    PubMed Central

    2011-01-01

    The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR). With this aim, the SAR of magnetic dispersions containing superparamagnetic magnetite nanoparticles bio-coated with polyacrylic acid of an average particle size of ≈10 nm has been evaluated separately by changing colloidal parameters such as the MNP concentration and the viscosity of the solvent. A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found. These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved. PACS: 80; 87; 87.85jf PMID:21711915

  12. Unimolecular Decomposition Rate of the Criegee Intermediate (CH3)2COO Measured Directly with UV Absorption Spectroscopy.

    PubMed

    Smith, Mica C; Chao, Wen; Takahashi, Kaito; Boering, Kristie A; Lin, Jim Jr-Min

    2016-07-14

    The unimolecular decomposition of (CH3)2COO and (CD3)2COO was measured by direct detection of the Criegee intermediate at temperatures from 283 to 323 K using time-resolved UV absorption spectroscopy. The unimolecular rate coefficient kd for (CH3)2COO shows a strong temperature dependence, increasing from 269 ± 82 s(-1) at 283 K to 916 ± 56 s(-1) at 323 K with an Arrhenius activation energy of ∼6 kcal mol(-1). The bimolecular rate coefficient for the reaction of (CH3)2COO with SO2, kSO2, was also determined in the temperature range 283 to 303 K. Our temperature-dependent values for kd and kSO2 are consistent with previously reported relative rate coefficients kd/kSO2 of (CH3)2COO formed from ozonolysis of tetramethyl ethylene. Quantum chemical calculations of kd for (CH3)2COO are consistent with the experiment, and the combination of experiment and theory for (CD3)2COO indicates that tunneling plays a significant role in (CH3)2COO unimolecular decomposition. The fast rates of unimolecular decomposition for (CH3)2COO measured here, in light of the relatively slow rate for the reaction of (CH3)2COO with water previously reported, suggest that thermal decomposition may compete with the reactions with water and with SO2 for atmospheric removal of the dimethyl-substituted Criegee intermediate. PMID:26985985

  13. From Complex B1 Mapping to Local SAR Estimation for Human Brain MR Imaging Using Multi-channel Transceiver Coil at 7T

    PubMed Central

    Zhang, Xiaotong; Schmitter, Sebastian; Van de Moortel, Pierre-François; Liu, Jiaen

    2014-01-01

    Elevated Specific Absorption Rate (SAR) associated with increased main magnetic field strength remains as a major safety concern in ultra-high-field (UHF) Magnetic Resonance Imaging (MRI) applications. The calculation of local SAR requires the knowledge of the electric field induced by radiofrequency (RF) excitation, and the local electrical properties of tissues. Since electric field distribution cannot be directly mapped in conventional MR measurements, SAR estimation is usually performed using numerical model-based electromagnetic simulations which, however, are highly time consuming and cannot account for the specific anatomy and tissue properties of the subject undergoing a scan. In the present study, starting from the measurable RF magnetic fields (B1) in MRI, we conducted a series of mathematical deduction to estimate the local, voxel-wise and subject-specific SAR for each single coil element using a multi-channel transceiver array coil. We first evaluated the feasibility of this approach in numerical simulations including two different human head models. We further conducted experimental study in a physical phantom and in two human subjects at 7T using a multi-channel transceiver head coil. Accuracy of the results is discussed in the context of predicting local SAR in the human brain at UHF MRI using multi-channel RF transmission. PMID:23508259

  14. SAR calibration: A technology review

    NASA Technical Reports Server (NTRS)

    Larson, R. W.; Politis, D. T.; Shuchman, R. A.

    1983-01-01

    Various potential applications of amplitude-calibrated SAR systems are briefly described, along with an estimate of calibration performance requirements. A review of the basic SAR calibration problem is given. For background purposes and to establish consistent definition of terms, various conventional SAR performance parameters are reviewed along with three additional parameters which are directly related to calibrated SAR systems. Techniques for calibrating a SAR are described. Included in the results presented are: calibration philosophy and procedures; review of the calibration signal generator technology development with results describing both the development of instrumentation and internal calibration measurements for two SAR systems; summary of analysis and measurements required to determine optimum retroreflector design and configuration for use as a reference for the absolute calibration of a SAR system; and summary of techniques for in-flight measurements of SAR antenna response.

  15. Segmentation Of Polarimetric SAR Data

    NASA Technical Reports Server (NTRS)

    Rignot, Eric J. M.; Chellappa, Rama

    1994-01-01

    Report presents one in continuing series of studies of segmentation of polarimetric synthetic-aperture-radar, SAR, image data into regions. Studies directed toward refinement of method of automated analysis of SAR data.

  16. Characterizing and estimating noise in InSAR and InSAR time series with MODIS

    USGS Publications Warehouse

    Barnhart, William D.; Lohman, Rowena B.

    2013-01-01

    InSAR time series analysis is increasingly used to image subcentimeter displacement rates of the ground surface. The precision of InSAR observations is often affected by several noise sources, including spatially correlated noise from the turbulent atmosphere. Under ideal scenarios, InSAR time series techniques can substantially mitigate these effects; however, in practice the temporal distribution of InSAR acquisitions over much of the world exhibit seasonal biases, long temporal gaps, and insufficient acquisitions to confidently obtain the precisions desired for tectonic research. Here, we introduce a technique for constraining the magnitude of errors expected from atmospheric phase delays on the ground displacement rates inferred from an InSAR time series using independent observations of precipitable water vapor from MODIS. We implement a Monte Carlo error estimation technique based on multiple (100+) MODIS-based time series that sample date ranges close to the acquisitions times of the available SAR imagery. This stochastic approach allows evaluation of the significance of signals present in the final time series product, in particular their correlation with topography and seasonality. We find that topographically correlated noise in individual interferograms is not spatially stationary, even over short-spatial scales (<10 km). Overall, MODIS-inferred displacements and velocities exhibit errors of similar magnitude to the variability within an InSAR time series. We examine the MODIS-based confidence bounds in regions with a range of inferred displacement rates, and find we are capable of resolving velocities as low as 1.5 mm/yr with uncertainties increasing to ∼6 mm/yr in regions with higher topographic relief.

  17. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  18. Risk factors for SARS infection within hospitals in Hanoi, Vietnam.

    PubMed

    Nishiyama, Ayako; Wakasugi, Naomi; Kirikae, Teruo; Quy, Tran; Ha, Le Dang; Ban, Vo Van; Long, Hoang Thuy; Keicho, Naoto; Sasazuki, Takehiko; Kuratsuji, Tadatoshi

    2008-09-01

    We investigated a nosocomial infection of severe acute respiratory syndrome (SARS) in Vietnam in 2003 and attempted to identify risk factors for SARS infection. Of the 146 subjects who came into contact with SARS patients at Hospital A, 43 (29.5%) developed SARS, and an additional 16 (11%) were asymptomatic but SARS-coronavirus (CoV) seropositive. The asymptomatic infection rate accounted for 15.5% of the total number of infected patients at Hospital A, which was higher than that of 6.5% observed at Hospital B, to where all patients from Hospital A were eventually transported (P<0.05). At Hospital A, the risk for developing SARS was 12.6 times higher in individuals not using a mask than in those using a mask. The SARS epidemic in Vietnam resulted in numerous secondary infections due to its unknown etiology and delayed recognition at the beginning of the epidemic. The consistent and proper use of a mask was shown to be crucial for constant protection against infection with SARS. PMID:18806349

  19. Design and optimization for variable rate selective excitation using an analytic RF scaling function

    NASA Astrophysics Data System (ADS)

    Gai, Neville D.; Zur, Yuval

    2007-11-01

    At higher B0 fields, specific absorption rate (SAR) deposition increases. Due to maximum SAR limitation, slice coverage decreases and/or scan time increases. Conventional selective RF pulses are played out in conjunction with a time independent field gradient. Variable rate selective excitation (VERSE) is a technique that modifies the original RF and gradient waveforms such that slice profile is unchanged. The drawback is that the slice profile for off-resonance spins is distorted. A new VERSE algorithm based on modeling the scaled waveforms as a Fermi function is introduced. It ensures that system related constraints of maximum gradient amplitude and slew rate are not exceeded. The algorithm can be used to preserve the original RF pulse duration while minimizing SAR and peak b1 or to minimize the RF pulse duration. The design is general and can be applied to any symmetrical or asymmetrical RF waveform. The algorithm is demonstrated by using it to (a) minimize the SAR of a linear phase RF pulse, (b) minimize SAR of a hyperbolic secant RF pulse, and (c) minimize the duration of a linear phase RF pulse. Images with a T1-FLAIR (T1 FLuid Attenuated Inversion Recovery) sequence using a conventional and VERSE adiabatic inversion RF pulse are presented. Comparison of images and scan parameters for different anatomies and coils shows increased scan coverage and decreased SAR with the VERSE inversion RF pulse, while image quality is preserved.

  20. admetSAR: a comprehensive source and free tool for assessment of chemical ADMET properties.

    PubMed

    Cheng, Feixiong; Li, Weihua; Zhou, Yadi; Shen, Jie; Wu, Zengrui; Liu, Guixia; Lee, Philip W; Tang, Yun

    2012-11-26

    Absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties play key roles in the discovery/development of drugs, pesticides, food additives, consumer products, and industrial chemicals. This information is especially useful when to conduct environmental and human hazard assessment. The most critical rate limiting step in the chemical safety assessment workflow is the availability of high quality data. This paper describes an ADMET structure-activity relationship database, abbreviated as admetSAR. It is an open source, text and structure searchable, and continually updated database that collects, curates, and manages available ADMET-associated properties data from the published literature. In admetSAR, over 210,000 ADMET annotated data points for more than 96,000 unique compounds with 45 kinds of ADMET-associated properties, proteins, species, or organisms have been carefully curated from a large number of diverse literatures. The database provides a user-friendly interface to query a specific chemical profile, using either CAS registry number, common name, or structure similarity. In addition, the database includes 22 qualitative classification and 5 quantitative regression models with highly predictive accuracy, allowing to estimate ecological/mammalian ADMET properties for novel chemicals. AdmetSAR is accessible free of charge at http://www.admetexp.org. PMID:23092397

  1. Simulation of SAR in the Human Body to Determine Effects of RF Heating

    NASA Astrophysics Data System (ADS)

    Michiyama, Tetsuyuki; Nikawa, Yoshio

    The body area network (BAN) has attracted attention because of its potential for high-grade wireless communication technology and its safety and high durability. Also, human area transmission of a BAN propagating at an ultra-wide band (UWB) has been demonstrated recently. When considering the efficiency of electromagnetic (EM) propagation inside the human body for BAN and hyperthermia treatment using RF, it is important to determine the mechanism of EM dissipation in the human body. A body heating system for hyperthermia must deposit EM energy deep inside the body. Also, it is important that the EM field generated by the implant system is sufficiently strong. In this study, the specific absorption rate (SAR) distribution is simulated using an EM simulator to consider the biological transmission mechanism and its effects. To utilize the EM field distribution using an implant system for hyperthermia treatment, the SAR distribution inside the human body is simulated. As a result, the SAR distribution is concentrated on the surface of human tissue, the muscle-bolus interface, the pancreas, the stomach, the spleen and the regions around bones. It can also be concentrated in bone marrow and cartilage. From these results, the appropriate location for the implant system is revealed on the basis of the current distribution and differences in the wave impedance of interfacing tissues. The possibility of accurate data transmission and suitable treatment planning is confirmed.

  2. Occupational exposure assessment on an FM mast: electric field and SAR values.

    PubMed

    Valič, Blaž; Kos, Bor; Gajšek, Peter

    2012-01-01

    Electric field strengths normally exceed the reference levels for occupational exposure in close vicinity to large frequency modulation (FM) transmitters. Thus, a detailed investigation on compliance with basic restrictions is needed before any administrative protection measures are applied. We prepared a detailed numerical model of a 20-kW FM transmitter on a 32-m mast. An electrically isolated anatomical human model was placed in 3 different positions inside the mast in the region where the values of the electric field were highest. The electric field strengths in this region were up to 700 V/m. The highest calculated whole-body specific absorption rate (SAR) was 0.48 W/kg, whereas the maximum 10-g average SAR in the head and trunk was 1.66 W/kg. The results show that the reference levels in the FM frequency range are very conservative for near field exposure. SAR values are not exceeded even for fields 10 times stronger than the reference levels. PMID:22721534

  3. Rate-based modeling of reactive absorption of CO{sub 2} and H{sub 2}S into aqueous methyldiethanolamine

    SciTech Connect

    Pacheco, M.A.; Rochelle, G.T.

    1998-10-01

    A general framework was developed to model the transport processes that take place during reactive absorption when both rate- and equilibrium-controlled reactions occur in the liquid phase. This framework was applied to the selective absorption of H{sub 2}S from fuel gas containing CO{sub 2} using aqueous methyldiethanolamine. A rate-based distillation column module was used for the column integration. The Maxwell-Stefan and enhancement factor theories were utilized. In packed columns, CO{sub 2} absorption is controlled by diffusion with fast chemical reactions; in trayed columns it is controlled primarily by physical absorption. Gas-film resistance is never significant for CO{sub 2} absorption. For H{sub 2}S absorption, gas- and liquid-film resistances are important, and diffusion of bisulfide controls the liquid-film resistance. Heat effects produce temperatures bulges that can cause equilibrium pinches at the maximum temperature. This phenomenon gives an optimum packing height for the H{sub 2}S removal. Trayed columns are more selective than packed columns for H{sub 2}S removal, primarily because of the larger number of liquid-film mass transfer units.

  4. Polarization effects and multipolarization SAR

    NASA Technical Reports Server (NTRS)

    Freeman, Anthony

    1992-01-01

    Imaging radar polarimeters are usually implemented using a Synthetic Aperture Radar (SAR) approach to give a high resolution image in two dimensions: range and azimuth. For each pixel in the image a polarimetric SAR gives sufficient information to characterize the polarimetric scattering properties of the imaged area (or target) as seen by the radar. Using a polarimetric SAR system as opposed to a single-polarization SAR system provides significantly more information about the target scattering mechanisms and allows better discrimination between different types of surfaces. In these notes a brief overview of SAR polarimetry is offered. The notes are intended as a text to accompany a lecture on SAR polarimetry as part of an AGARD-NATO course. Covered in the notes are the following: the polarization properties of electromagnetic waves; the concepts of radar scattering and measuring radar backscatter with a SAR; polarization synthesis; scattering matrix, Stokes matrix, and covariance matrix representations of polarimetric SAR data; polarization signature plots; design and calibration of polarimetric SAR systems; polarization filtering for target detection; fitting a simple model to polarimetric SAR measurements of naturally occurring features; and supervised classification of polarimetric SAR data.

  5. Understanding SARS with Wolfram approach.

    PubMed

    Li, Da-Wei; Pan, Yu-Xi; Duan, Yun; Hung, Zhen-De; Xu, Ming-Qing; He, Lin

    2004-01-01

    Stepping acquired immunodeficiency syndrome (AIDS), severe acute respiratory syndrome (SARS) as another type of disease has been threatening mankind since late last year. Many scientists worldwide are making great efforts to study the etiology of this disease with different approaches. 13 species of SARS virus have been sequenced. However, most people still largely rely on the traditional methods with some disadvantages. In this work, we used Wolfram approach to study the relationship among SARS viruses and between SARS viruses and other types of viruses, the effect of variations on the whole genome and the advantages in the analysis of SARS based on this novel approach. As a result, the similarities between SARS viruses and other coronaviruses are not really higher than those between SARS viruses and non-coronaviruses. PMID:14732867

  6. Bistatic SAR: Proof of Concept.

    SciTech Connect

    Yocky, David A.; Doren, Neall E.; Bacon, Terry A.; Wahl, Daniel E.; Eichel, Paul H.; Jakowatz, Charles V,; Delaplain, Gilbert G.; Dubbert, Dale F.; Tise, Bertice L.; White, Kyle R.

    2014-10-01

    Typical synthetic aperture RADAR (SAR) imaging employs a co-located RADAR transmitter and receiver. Bistatic SAR imaging separates the transmitter and receiver locations. A bistatic SAR configuration allows for the transmitter and receiver(s) to be in a variety of geometric alignments. Sandia National Laboratories (SNL) / New Mexico proposed the deployment of a ground-based RADAR receiver. This RADAR receiver was coupled with the capability of digitizing and recording the signal collected. SNL proposed the possibility of creating an image of targets the illuminating SAR observes. This document describes the developed hardware, software, bistatic SAR configuration, and its deployment to test the concept of a ground-based bistatic SAR. In the proof-of-concept experiments herein, the RADAR transmitter will be a commercial SAR satellite and the RADAR receiver will be deployed at ground level, observing and capturing RADAR ground/targets illuminated by the satellite system.

  7. EARSEC SAR processing system

    NASA Astrophysics Data System (ADS)

    Protheroe, Mark; Sloggett, David R.; Sieber, Alois J.

    1994-12-01

    Traditionally, the production of high quality Synthetic Aperture Radar imagery has been an area where a potential user would have to expend large amounts of money in either the bespoke development of a processing chain dedicated to his requirements or in the purchase of a dedicated hardware platform adapted using accelerator boards and enhanced memory management. Whichever option the user adopted there were limitations based on the desire for a realistic throughput in data load and time. The user had a choice, made early in the purchase, for either a system that adopted innovative algorithmic manipulation, to limit the processing time of the purchase of expensive hardware. The former limits the quality of the product, while the latter excludes the user from any visibility into the processing chain. Clearly there was a need for a SAR processing architecture that gave the user a choice into the methodology to be adopted for a particular processing sequence, allowing him to decide on either a quick (lower quality) product or a detailed slower (high quality) product, without having to change the algorithmic base of his processor or the hardware platform. The European Commission, through the Advanced Techniques unit of the Joint Research Centre (JRC) Institute for Remote Sensing at Ispra in Italy, realizing the limitations on current processing abilities, initiated its own program to build airborne SAR and Electro-Optical (EO) sensor systems. This program is called the European Airborne Remote Sensing Capabilities (EARSEC) program. This paper describes the processing system developed for the airborne SAR sensor system. The paper considers the requirements for the system and the design of the EARSEC Airborne SAR Processing System. It highlights the development of an open SAR processing architecture where users have full access to intermediate products that arise from each of the major processing stages. It also describes the main processing stages in the overall

  8. Real-time optical processor prototype for remote SAR applications

    NASA Astrophysics Data System (ADS)

    Marchese, Linda; Doucet, Michel; Harnisch, Bernd; Suess, Martin; Bourqui, Pascal; Legros, Mathieu; Desnoyers, Nichola; Guillot, Ludovic; Mercier, Luc; Savard, Maxime; Martel, Anne; Châteauneuf, François; Bergeron, Alain

    2009-09-01

    A Compact Real-Time Optical SAR Processor has been successfully developed and tested. SAR, or Synthetic Aperture Radar, is a powerful tool providing enhanced day and night imaging capabilities. SAR systems typically generate large amounts of information generally in the form of complex data that are difficult to compress. Specifically, for planetary missions and unmanned aerial vehicle (UAV) systems with limited communication data rates this is a clear disadvantage. SAR images are typically processed electronically applying dedicated Fourier transformations. This, however, can also be performed optically in real-time. Indeed, the first SAR images have been optically processed. The optical processor architecture provides inherent parallel computing capabilities that can be used advantageously for the SAR data processing. Onboard SAR image generation would provide local access to processed information paving the way for real-time decision-making. This could eventually benefit navigation strategy and instrument orientation decisions. Moreover, for interplanetary missions, onboard analysis of images could provide important feature identification clues and could help select the appropriate images to be transmitted to Earth, consequently helping bandwidth management. This could ultimately reduce the data throughput requirements and related transmission bandwidth. This paper reviews the design of a compact optical SAR processor prototype that would reduce power, weight, and size requirements and reviews the analysis of SAR image generation using the table-top optical processor. Various SAR processor parameters such as processing capabilities, image quality (point target analysis), weight and size are reviewed. Results of image generation from simulated point targets as well as real satellite-acquired raw data are presented.

  9. A comparative numerical study of rotating and stationary RF coils in terms of flip angle and specific absorption rate for 7 T MRI

    NASA Astrophysics Data System (ADS)

    Trakic, A.; Jin, J.; Li, M. Y.; McClymont, D.; Weber, E.; Liu, F.; Crozier, S.

    2013-11-01

    While high-field magnetic resonance imaging promises improved image quality and faster scan time, it is affected by non-uniform flip angle distributions and unsafe specific absorption rate levels within the patient, as a result of the complicated radiofrequency (RF) field - tissue interactions. This numerical study explored the possibility of using a single mechanically rotating RF coil for RF shimming and specific absorption rate management applications at 7 T. In particular, this new approach (with three different RF coil element arrangements) was compared against both an 8-channel parallel coil array and a birdcage volume coil, with and without RF current optimisation. The evaluation was conducted using an in-house developed and validated finite-difference time-domain method in conjunction with a tissue-equivalent human head model. It was found that, without current optimisation, the rotating RF coil method produced a more uniform flip angle distribution and a lower maximum global and local specific absorption rate compared to the 8-channel parallel coil array and birdcage resonator. In addition, due to the large number of degrees of freedom in the form of rotated sensitivity profiles, the rotating RF coil approach exhibited good RF shimming and specific absorption rate management performance. This suggests that the proposed method can be useful in the development of techniques that address contemporary RF issues associated with high-field magnetic resonance imaging.

  10. Ionospheric composition in SAR-arcs. [Stable Auroral Red Arcs

    NASA Technical Reports Server (NTRS)

    Raitt, W. J.; Schunk, R. W.; Banks, P. M.

    1976-01-01

    Theoretical ion and electron density profiles in the SAR-arc region are calculated using a model of the ionosphere based on the coupled continuity, momentum, and energy equations for O(+), NO(+), and O2(+). It is found that an increase in the reaction O(+) + N2 yields NO(+) + N, which results from enhanced N2 vibrational excitation due to the high electron temperatures found in SAR arcs, can cause a reduction in F-region electron densities by up to a factor of two. The increase in the O(+) + N2 reaction rate is shown to result in a marked change in the ion composition in SAR arcs, with NO(+) being an important ion up to altitudes of about 350 km at night. Since observed electron-density depressions in SAR arcs generally vary between factors of two and seven, it is concluded that the increase in the O(+) + N2 reaction rate cannot account for these depressions by itself.

  11. Changes in ruminal volatile fatty acid production and absorption rate during the dry period and early lactation as affected by rate of increase of concentrate allowance.

    PubMed

    Dieho, K; Dijkstra, J; Schonewille, J T; Bannink, A

    2016-07-01

    The aim of the present experiment was to study changes in volatile fatty acid (VFA) production using an isotope dilution technique, and changes in VFA fractional absorption rate (kaVFA) using a buffer incubation technique (BIT) during the dry period and early lactation, as affected by the postpartum (pp) rate of increase of concentrate allowance. The current results are complementary to previously reported changes on rumen papillae morphology from the same experiment. From 50 d antepartum to 80 d pp, VFA production rate was measured 5 times and kaVFA was measured 10 times in 12 rumen-cannulated Holstein Friesian cows. Cows had free access to a mixed ration, consisting of grass and corn silage, soybean meal, and (dry period only) chopped straw. Treatment consisted of either a rapid (RAP; 1.0 kg of DM/d; n=6) or gradual (GRAD; 0.25 kg of DM/d; n=6) increase of concentrate allowance (up to 10.9 kg of DM/d), starting at 4 d pp, aimed at creating a contrast in rumen-fermentable organic matter intake. For the BIT, rumen contents were evacuated, the rumen washed, and a standardized buffer fluid introduced [120 mM VFA, 60% acetic (Ac), 25% propionic (Pr), and 15% butyric (Bu) acid; pH 5.9 and Co-EDTA as fluid passage marker]. For the isotope dilution technique, a pulse-dose of (13)C-labeled Ac, Pr, and Bu and Co-EDTA as fluid passage marker was infused. The rate of total VFA production was similar between treatments and was 2 times higher during the lactation (114 mol/d) than the dry period (53 mol/d). Although papillae surface area at 16, 30, and 44 d pp was greater in RAP than GRAD, Bu and Ac production at these days did not differ between RAP and GRAD, whereas at 16 d pp RAP produced more Pr than GRAD. These results provide little support for the particular proliferative effects of Bu on papillae surface area. Similar to developments in papillae surface area in the dry period and early lactation, the kaVFA (per hour), measured using the BIT, decreased from 0.45 (Ac), 0

  12. Evaluation of SAR in a human body model due to wireless power transmission in the 10 MHz band

    NASA Astrophysics Data System (ADS)

    Laakso, Ilkka; Tsuchida, Shogo; Hirata, Akimasa; Kamimura, Yoshitsugu

    2012-08-01

    This study discusses a computational method for calculating the specific absorption rate (SAR) due to a wireless power transmission system in the 10 MHz frequency band. A two-step quasi-static method comprised of the method of moments and the scalar potential finite-difference method are proposed. The applicability of the quasi-static approximation for localized exposure in this frequency band is discussed by comparing the SAR in a lossy dielectric cylinder computed with a full-wave electromagnetic analysis and the quasi-static approximation. From the computational results, the input impedance of the resonant coils was affected by the existence of the cylinder. On the other hand, the magnetic field distribution in free space and considering the cylinder and an impedance matching circuit were in good agreement; the maximum difference in the amplitude of the magnetic field was 4.8%. For a cylinder-coil distance of 10 mm, the difference between the peak 10 g averaged SAR in the cylinder computed with the full-wave electromagnetic method and our quasi-static method was 7.8%. These results suggest that the quasi-static approach is applicable for conducting the dosimetry of wireless power transmission in the 10 MHz band. With our two-step quasi-static method, the SAR in the anatomically based model was computed for different exposure scenarios. From those computations, the allowable input power satisfying the limit of a peak 10 g averaged SAR of 2.0 W kg-1 was 830 W in the worst case exposure scenario with a coil positioned at a distance of 30 mm from the chest.

  13. SAR based adaptive GMTI

    NASA Astrophysics Data System (ADS)

    Vu, Duc; Guo, Bin; Xu, Luzhou; Li, Jian

    2010-04-01

    We consider ground moving target indication (GMTI) and target velocity estimation based on multi-channel synthetic aperture radar (SAR) images. Via forming velocity versus cross-range images, we show that small moving targets can be detected even in the presence of strong stationary ground clutter. Moreover, the velocities of the moving targets can be estimated, and the misplaced moving targets can be placed back to their original locations based on the estimated velocities. Adaptive beamforming techniques, including Capon and generalizedlikelihood ratio test (GLRT), are used to form velocity versus cross-range images for each range bin of interest. The velocity estimation ambiguities caused by the multi-channel array geometry are analyzed. We also demonstrate the effectiveness of our approaches using the Air Force Research Laboratory (AFRL) publicly-released Gotcha SAR based GMTI data set.

  14. Interseismic deformation and creep along the central section of the North Anatolian Fault (Turkey): InSAR observations and implications for rate-and-state friction properties

    NASA Astrophysics Data System (ADS)

    Kaneko, Y.; Fialko, Y.; Sandwell, D. T.; Tong, X.; Furuya, M.

    2013-01-01

    AbstractWe present high-resolution measurements of interseismic deformation along the central section of the North Anatolian Fault (NAF) in Turkey using interferometric synthetic aperture radar data from the Advanced Land Observing Satellite and Envisat missions. We generated maps of satellite line-of-sight velocity using five ascending Advanced Land Observing Satellite tracks and one descending Envisat track covering the NAF between 31.2°E and 34.3°E. The line-of-sight velocity reveals discontinuities of up to ˜5 mm/yr across the Ismetpasa segment of the NAF, implying surface creep at a <span class="hlt">rate</span> of ˜9 mm/yr; this is a large fraction of the inferred slip <span class="hlt">rate</span> of the NAF (21-25 mm/yr). The lateral extent of significant surface creep is about 75 km. We model the inferred surface velocity and shallow fault creep using numerical simulations of spontaneous earthquake sequences that incorporate laboratory-derived <span class="hlt">rate</span> and state friction. Our results indicate that frictional behavior in the Ismetpasa segment is velocity strengthening at shallow depths and transitions to velocity weakening at a depth of 3-6 km. The inferred depth extent of shallow fault creep is 5.5-7 km, suggesting that the deeper locked portion of the partially creeping segment is characterized by a higher stressing <span class="hlt">rate</span>, smaller events, and shorter recurrence interval. We also reproduce surface velocity in a locked segment of the NAF by fault models with velocity-weakening conditions at shallow depth. Our results imply that frictional behavior in a shallow portion of major active faults with little or no shallow creep is mostly velocity weakening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7699E..0BC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7699E..0BC"><span id="translatedtitle">Bayesian <span class="hlt">SAR</span> imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Zhaofu; Tan, Xing; Xue, Ming; Li, Jian</p> <p>2010-04-01</p> <p>We introduce a maximum a posteriori (MAP) algorithm and a sparse learning via iterative minimization (SLIM) algorithm to synthetic aperture radar (<span class="hlt">SAR</span>) imaging. Both MAP and SLIM are sparse signal recovery algorithms with excellent sidelobe suppression and high resolution properties. The former cyclically maximizes the a posteriori probability density function for a given sparsity promoting prior, while the latter cyclically minimizes a regularized least squares cost function. We show how MAP and SLIM can be adapted to the <span class="hlt">SAR</span> imaging application and used to enhance the image quality. We evaluate the performance of MAP and SLIM using the simulated complex-valued backscattered data from a backhoe vehicle. The numerical results show that both MAP and SLIM satisfactorily suppress the sidelobes and yield higher resolution than the conventional matched filter or delay-and-sum (DAS) approach. MAP and SLIM outperform the widely used compressive sampling matching pursuit (CoSaMP) algorithm, which requires the delicate choice of user parameters. Compared with the recently developed iterative adaptive approach (IAA), MAP and SLIM are computationally more efficient, especially with the help of fast Fourier transform (FFT). Also, the a posteriori distribution given by the algorithms provides us with a basis for the analysis of the statistical properties of the <span class="hlt">SAR</span> image pixels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9093E..0PP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9093E..0PP"><span id="translatedtitle">Circular <span class="hlt">SAR</span> GMTI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Page, Douglas; Owirka, Gregory; Nichols, Howard; Scarborough, Steven</p> <p>2014-06-01</p> <p>We describe techniques for improving ground moving target indication (GMTI) performance in multi-channel synthetic aperture radar (<span class="hlt">SAR</span>) systems. Our approach employs a combination of moving reference processing (MRP) to compensate for defocus of moving target <span class="hlt">SAR</span> responses and space-time adaptive processing (STAP) to mitigate the effects of strong clutter interference. Using simulated moving target and clutter returns, we demonstrate focusing of the target return using MRP, and discuss the effect of MRP on the clutter response. We also describe formation of adaptive degrees of freedom (DOFs) for STAP filtering of MRP processed data. For the simulated moving target in clutter example, we demonstrate improvement in the signal to interference plus noise (SINR) loss compared to more standard algorithm configurations. In addition to MRP and STAP, the use of tracker feedback, false alarm mitigation, and parameter estimation techniques are also described. A change detection approach for reducing false alarms from clutter discretes is outlined, and processing of a measured data coherent processing interval (CPI) from a continuously orbiting platform is described. The results demonstrate detection and geolocation of a high-value target under track. The endoclutter target is not clearly visible in single-channel <span class="hlt">SAR</span> chips centered on the GMTI track prediction. Detections are compared to truth data before and after geolocation using measured angle of arrival (AOA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESASP.731E..12M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESASP.731E..12M"><span id="translatedtitle">Deformation Monitoring of Urban Infrastructure by Tomographic <span class="hlt">SAR</span> Using Multi-View Terra<span class="hlt">SAR</span>-X Data Stacks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montazeri, Sina; Zhu, Xiaoxiang; Eineder, Michael; Hanssen, Ramon F.; Bamler, Richard</p> <p>2015-05-01</p> <p>Synthetic Aperture Radar Tomography (Tomo<span class="hlt">SAR</span>) coupled with data from modern <span class="hlt">SAR</span> sensors, such as the German Terra<span class="hlt">SAR</span>-X (TS-X) produces the most detailed three-dimensional (3D) maps by distinguishing among multiple scatterers within a resolution cell. Furthermore, multi-temporal Tomo<span class="hlt">SAR</span> allows for recording the underlying deformation phenomenon of each individual scatterer. One of the limitations of using In<span class="hlt">SAR</span> techniques, including Tomo<span class="hlt">SAR</span>, is that they only measure deformation along the radar Line-of-Sight (LOS). In order to enhance the understanding of deformation, a decomposition of the observed LOS displacement into the 3D deformation vector in the local coordinate system is desired. In this paper we propose a method, based on L1 norm minimization within local spatial cubes, to reconstruct 3D deformation vectors from Tomo<span class="hlt">SAR</span> point clouds available from, at least, three different viewing geometries. The methodology is applied on two pair of cross-heading TS-X spotlight image stacks over the city of Berlin. The linear deformation <span class="hlt">rate</span> and amplitude of seasonal deformation are decomposed and the results from two individual test sites with remarkable deformation patterns are discussed in details.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.H24C..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.H24C..07W"><span id="translatedtitle">Wetland In<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wdowinski, S.; Kim, S.; Amelung, F.; Dixon, T.</p> <p>2006-12-01</p> <p>Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of In<span class="hlt">SAR</span> provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of In<span class="hlt">SAR</span> for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MNRAS.427.1209C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MNRAS.427.1209C"><span id="translatedtitle">Herschel-ATLAS: the far-infrared properties and star formation <span class="hlt">rates</span> of broad <span class="hlt">absorption</span> line quasi-stellar objects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao Orjales, J. M.; Stevens, J. A.; Jarvis, M. J.; Smith, D. J. B.; Hardcastle, M. J.; Auld, R.; Baes, M.; Cava, A.; Clements, D. L.; Cooray, A.; Coppin, K.; Dariush, A.; De Zotti, G.; Dunne, L.; Dye, S.; Eales, S.; Hopwood, R.; Hoyos, C.; Ibar, E.; Ivison, R. J.; Maddox, S.; Page, M. J.; Valiante, E.</p> <p>2012-12-01</p> <p>We have used data from the Herschel Astrophysical Terahertz Large-Area Survey (H-ATLAS) at 250, 350 and 500 μm to determine the far-infrared (FIR) properties of 50 broad <span class="hlt">absorption</span> line quasars (BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and one low-ionization BAL QSO (LoBAL) which are compared against a sample of 329 non-BAL QSOs. These samples are matched over the redshift range 1.5 ≤ z < 2.3 and in absolute i-band magnitude over the range -28 ≤ Mi ≤ -24. Of these, three BAL QSOs (HiBALs) and 27 non-BAL QSOs are detected at the >5 σ level. We calculate star formation <span class="hlt">rates</span> (SFRs) for our individually detected HiBAL QSOs and the non-detected LoBAL QSO as well as average SFRs for the BAL and non-BAL QSO samples based on stacking the Herschel data. We find no difference between the HiBAL and non-BAL QSO samples in the FIR, even when separated based on differing BAL QSO classifications. Using Mrk 231 as a template, the weighted mean SFR is estimated to be ≈240 ± 21 M⊙ yr-1 for the full sample, although this figure should be treated as an upper limit if active galactic nucleus (AGN)-heated dust makes a contribution to the FIR emission. Despite tentative claims in the literature, we do not find a dependence of C IV equivalent width on FIR emission, suggesting that the strength of any outflow in these objects is not linked to their FIR output. These results strongly suggest that BAL QSOs (more specifically HiBALs) can be accommodated within a simple AGN unified scheme in which our line of sight to the nucleus intersects outflowing material. Models in which HiBALs are caught towards the end of a period of enhanced spheroid and black hole growth, during which a wind terminates the star formation activity, are not supported by the observed FIR properties. The Herschel-ATLAS is a project with Herschel, which is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptMa..46..578A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptMa..46..578A"><span id="translatedtitle">Modulation of internal conversion <span class="hlt">rate</span> and nonlinear <span class="hlt">absorption</span> in meso-tetraphenylporphyrins by donor/acceptor substitutes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ao, Guanghong; Qian, Xuemin; Xiao, Zhengguo; Li, Zhongguo; Nie, Zhongquan; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin</p> <p>2015-08-01</p> <p>Meso-tetraphenylporphyrin (TPP), (meso-tetrakis(4-cyanophenyl)porphyrin [TPP(CN)4)] and (meso-tetrakis(4-methoxyphenyl)porphyrin [TPP(OMe)4]) are synthesized. The donor methoxy substitute (OMe) and acceptor cyano substitute (CN) are introduced into TPP in order to examine their influence on the photophysical properties of TPP. The nonlinear <span class="hlt">absorption</span> properties of these three porphyrins are studied using open-aperture Z-scan and time-resolved pump-probe techniques in picosecond and nanosecond regimes, and the results are elucidated successfully by a five-level model. As compared to TPP, TPP(OMe)4 exhibits an accelerated internal conversion from S1 to S0 state (0.02 ns), and S1 to T1 state (0.03 ns). Moreover, a changeover from saturable <span class="hlt">absorption</span> to reverse saturable <span class="hlt">absorption</span> is observed in TPP(OMe)4 in the ps regime. Whereas the nonlinear <span class="hlt">absorption</span> behavior of TPP(CN)4 is similar to that of TPP. The results imply that these two substituents, especially the OMe group, could modulate the photophysical properties of TPP, which may provide a useful option for porphyrin-related applications.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PMB....57..143W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PMB....57..143W"><span id="translatedtitle">Statistical determination of whole-body average <span class="hlt">SARs</span> in a 2 GHz whole-body exposure system for unrestrained pregnant and newborn rats</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Jianqing; Wake, Kanako; Kawai, Hiroki; Watanabe, Soichi; Fujiwara, Osamu</p> <p>2012-01-01</p> <p>A 2 GHz whole-body exposure to rats over a multigeneration has been conducted as part of bio-effect research in Japan. In this study, the rats moved freely in the cage inside the exposure system. From observation of the activity of rats in the cage, we found that the rats do not stay in each position with uniform possibility. In order to determine the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) during the entire exposure period with high accuracy, we present a new approach to statistically determine the <span class="hlt">SAR</span> level in an exposure system. First, we divided the rat cage in the exposure system into several small areas, and derived the fraction of time the rats spent in each small area based on the classification of the documentary photos of rat activity. Then, using the fraction of time spent in each small area as a weighting factor, we calculated the statistical characteristics of the whole-body average <span class="hlt">SAR</span> for pregnant rats and young rats during the entire exposure period. As a result, this approach gave the statistical distribution as well as the corresponding mean value, median value and mode value for the whole-body <span class="hlt">SAR</span> so that we can reasonably clarify the relationship between the exposure level and possible biological effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PMB....53.1511C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PMB....53.1511C"><span id="translatedtitle">Variability analysis of <span class="hlt">SAR</span> from 20 MHz to 2.4 GHz for different adult and child models using finite-difference time-domain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conil, E.; Hadjem, A.; Lacroux, F.; Wong, M. F.; Wiart, J.</p> <p>2008-03-01</p> <p>This paper deals with the variability of body models used in numerical dosimetry studies. Six adult anthropomorphic voxel models have been collected and used to build 5-, 8- and 12-year-old children using a morphing method respecting anatomical parameters. Finite-difference time-domain calculations of a specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) have been performed for a range of frequencies from 20 MHz to 2.4 GHz for isolated models illuminated by plane waves. A whole-body-averaged <span class="hlt">SAR</span> is presented as well as the average on specific tissues such as skin, muscles, fat or bones and the average on specific parts of the body such as head, legs, arms or torso. Results point out the variability of adult models. The standard deviation of whole-body-averaged <span class="hlt">SAR</span> of adult models can reach 40%. All phantoms are exposed to the ICNIRP reference levels. Results show that for adults, compliance with reference levels ensures compliance with basic restrictions, but concerning children models involved in this study, the whole-body-averaged <span class="hlt">SAR</span> goes over the fundamental safety limits up to 40%. For more information on this article, see medicalphysicsweb.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26406030','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26406030"><span id="translatedtitle"><span class="hlt">SAR</span> and thermal response effects of a two-arm Archimedean spiral coil in a magnetic induction sensor on a human head.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Ziyi; Liu, Peiguo; Zhou, Dongming; Zhang, Liang; Ding, Liang</p> <p>2015-01-01</p> <p>This study investigates the radiation safety of a newly designed magnetic induction sensor. This novel magnetic induction sensor uses a two-arm Archimedean spiral coil (TAASC) as the exciter. A human head model with a real anatomical structure was used to calculate the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) and temperature change. Computer Simulation Technology (CST) was used to determine the values of the peak 10-g <span class="hlt">SAR</span> under different operating parameters (current, frequency, horizontal distance between the excitation coil and the receiver coil, vertical distance between the top of the head model and the XOY plane, position of excitation coil, and volume of hemorrhage). Then, the highest response for the <span class="hlt">SAR</span> and temperature rise was determined. The results showed that this new magnetic induction sensor is safe in the initial state; for safety reasons, the TAASC current should not exceed 4 A. The scalp tissue absorbed most of the electromagnetic energy. The TAASC's <span class="hlt">SAR</span>/thermal performance was close to that of the circular coil. PMID:26406030</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18367785','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18367785"><span id="translatedtitle">Variability analysis of <span class="hlt">SAR</span> from 20 MHz to 2.4 GHz for different adult and child models using finite-difference time-domain.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Conil, E; Hadjem, A; Lacroux, F; Wong, M F; Wiart, J</p> <p>2008-03-21</p> <p>This paper deals with the variability of body models used in numerical dosimetry studies. Six adult anthropomorphic voxel models have been collected and used to build 5-, 8- and 12-year-old children using a morphing method respecting anatomical parameters. Finite-difference time-domain calculations of a specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) have been performed for a range of frequencies from 20 MHz to 2.4 GHz for isolated models illuminated by plane waves. A whole-body-averaged <span class="hlt">SAR</span> is presented as well as the average on specific tissues such as skin, muscles, fat or bones and the average on specific parts of the body such as head, legs, arms or torso. Results point out the variability of adult models. The standard deviation of whole-body-averaged <span class="hlt">SAR</span> of adult models can reach 40%. All phantoms are exposed to the ICNIRP reference levels. Results show that for adults, compliance with reference levels ensures compliance with basic restrictions, but concerning children models involved in this study, the whole-body-averaged <span class="hlt">SAR</span> goes over the fundamental safety limits up to 40%. PMID:18367785</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5575986','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5575986"><span id="translatedtitle">Monomeric C-phycocyanin at room temperature and 77 K. Resolution of the <span class="hlt">absorption</span> and fluorescence spectra of the individual chromophores and the energy-transfer <span class="hlt">rate</span> constants</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Debreczeny, M.P.; Sauer, K. Univ. of California, Berkeley, CA ); Zhou, J.; Bryant, D.A. )</p> <p>1993-09-23</p> <p>At both room temperature (RT) and 77 K, the <span class="hlt">absorption</span> and fluorescence spectra of the three individual chromophore types ([alpha][sub 84], [beta][sub 84], and [beta][sub 155]) found in monomeric C-phycocyanin ([alpha][sup PC][beta][sup PC]), isolated from the cyanobacterium Synechococcus sp. PCC 7002, were resolved along with the <span class="hlt">rates</span> of energy transfer between the chromophores. The cpcB/C155S mutant, whose PC is missing the [beta][sub 155] chromophore, was useful in effecting this resolution. At RT, the single broad peak in the visible region of the <span class="hlt">absorption</span> spectrum of ([alpha][sup PC][beta][sup PC]) was resolved into its three-component spectra by comparing the steady-state <span class="hlt">absorption</span> spectra of the isolated wild-type [alpha] subunit of PC ([alpha][sup PC]) (containing only the [alpha][sub 84] chromophore) with those of the monomeric PCs isolated from the mutant strain ([alpha][sup PC][beta]*) and the wild-type strain ([alpha][sup PC][beta][sup PC]). At 77 K, the visible region of the <span class="hlt">absorption</span> spectrum of ([alpha][sup PC][beta][sup PC]) splits into two peaks. This partial resolution at 77 K of the chromophore spectra of ([alpha][sup PC][beta][sup PC]) when compared with the 77 K <span class="hlt">absorption</span> spectra of [alpha][sup PC], [beta][sup PC], and ([alpha][sup PC][beta]*) provided a confirmation of our RT assignments of the chromophore <span class="hlt">absorption</span> spectra. 38 refs., 9 figs., 6 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1159447','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1159447"><span id="translatedtitle">Bistatic <span class="hlt">SAR</span>: Imagery & Image Products.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yocky, David A.; Wahl, Daniel E.; Jakowatz, Charles V,</p> <p>2014-10-01</p> <p>While typical <span class="hlt">SAR</span> imaging employs a co-located (monostatic) RADAR transmitter and receiver, bistatic <span class="hlt">SAR</span> imaging separates the transmitter and receiver locations. The transmitter and receiver geometry determines if the scattered signal is back scatter, forward scatter, or side scatter. The monostatic <span class="hlt">SAR</span> image is backscatter. Therefore, depending on the transmitter/receiver collection geometry, the captured imagery may be quite different that that sensed at the monostatic <span class="hlt">SAR</span>. This document presents imagery and image products formed from captured signals during the validation stage of the bistatic <span class="hlt">SAR</span> research. Image quality and image characteristics are discussed first. Then image products such as two-color multi-view (2CMV) and coherent change detection (CCD) are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15609567','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15609567"><span id="translatedtitle">RF dosimetry: a comparison between power <span class="hlt">absorption</span> of female and male numerical models from 0.1 to 4 ghz.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sandrini, L; Vaccari, A; Malacarne, C; Cristoforetti, L; Pontalti, R</p> <p>2004-11-21</p> <p>Realistic numerical models of human subjects and their surrounding environment represent the basic points of radiofrequency (RF) electromagnetic dosimetry. This also involves differentiating the human models in men and women, possibly with different body shapes and postures. In this context, the aims of this paper are, firstly, to propose a female dielectric anatomical model (fDAM) and, secondly, to compare the power <span class="hlt">absorption</span> distributions of a male and a female model from 0.1 to 4 GHz. For realizing the fDAM, a magnetic resonance imaging tomographer to acquire images and a recent technique which avoids the discrete segmentation of body tissues into different types have been used. Simulations have been performed with the FDTD method by using a novel filtering-based subgridding algorithm. The latter is applied here for the first time to dosimetry, allowing an abrupt mesh refinement by a factor of up to 7. The results show that the whole-body-averaged specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (WBA-<span class="hlt">SAR</span>) of the female model is higher than that of the male counterpart, mainly because of a thicker subcutaneous fat layer. In contrast, the maximum averaged <span class="hlt">SAR</span> over 1 g (1gA-<span class="hlt">SAR</span>) and 10 g (10gA-<span class="hlt">SAR</span>) does not depend on gender, because it occurs in regions where no subcutaneous fat layer is present. PMID:15609567</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004ITEIS.124.2427F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004ITEIS.124.2427F"><span id="translatedtitle">Thermal Index Evaluation of Local <span class="hlt">SAR</span> in MRI-Based Head Models of Adult and Children for Portable Telephones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujiwara, Osamu; Miyamoto, Kayoko; Wang, Jianqing</p> <p></p> <p>Biological hazards due to radio-frequency (RF) waves result mainly from the temperature rise in tissue. It should be, therefore, clarified to what extent the RF waves of portable telephones increase the temperature-rise in human brain that includes the central part governing the body-temperature regulation function. In this paper, we calculated both the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) and the resultant temperature-rise for 900 MHz and 2 GHz portable telephones using the finite-difference time-domain (FDTD) method for three typical use positions, i.e., the vertical position, cheek position and tilt position. As a result, we found that there was an increase for median and 1% value of the cumulative distribution of temperature-rise in children’s brains for any use positions of the portable telephones compared to that in the adult’s brain, and also that the increasing trend in children’s brains for temperature-rise is identical to the temperature-rise trend in children’s hypothalamus. In addition, we found that the ten-gram averaged peak <span class="hlt">SAR</span> among the adult and children heads had the same trend as that of the 0.1% value of the relatively cumulative distribution of temperature-rise, which shows that the ten-gram averaged peak <span class="hlt">SAR</span> reflects only the localized temperature-rise in the brain surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19589878','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19589878"><span id="translatedtitle">FDTD calculations of <span class="hlt">SAR</span> for child voxel models in different postures between 10 MHz and 3 GHz.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Findlay, R P; Lee, A-K; Dimbylow, P J</p> <p>2009-08-01</p> <p>Calculations of specific energy <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) have been performed on the rescaled NORMAN 7-y-old voxel model and the Electronics and Telecommunications Research Institute (ETRI) child 7-y-old voxel model in the standing arms down, arms up and sitting postures. These calculations were for plane-wave exposure under isolated and grounded conditions between 10 MHz and 3 GHz. It was found that there was little difference at each resonant frequency between the whole-body averaged <span class="hlt">SAR</span> values calculated for the NORMAN and ETRI 7-y-old models for each of the postures studied. However, when compared with the arms down posture, raising the arms increased the <span class="hlt">SAR</span> by up to 25%. Electric field values required to produce the International Commission on Non-Ionizing Radiation Protection and Institute of Electrical and Electronic Engineers public basic restriction were calculated, and compared with reference levels for the different child models and postures. These showed that, under certain worst-case exposure conditions, the reference levels may not be conservative. PMID:19589878</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PMB....55.1041M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PMB....55.1041M"><span id="translatedtitle">Comparison of <span class="hlt">SAR</span> and induced current densities in adults and children exposed to electromagnetic fields from electronic article surveillance devices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martínez-Búrdalo, M.; Sanchis, A.; Martín, A.; Villar, R.</p> <p>2010-02-01</p> <p>Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of different size (REMCOM/Hershey and Virtual Family), simulating adult and child bodies, are exposed to a 10 MHz pass-by panel-type EAS consisting of two overlapping current-carrying coils. Two different relative positions between the EAS and the body (frontal and lateral exposures), which imply the exposure of different parts of the body at different distances, have been considered. In all cases, induced current densities in tissues of the central nervous system and specific <span class="hlt">absorption</span> <span class="hlt">rates</span> (<span class="hlt">SARs</span>) are calculated to be compared with the limits from the guidelines. Results show that induced current densities are lower in the case of adult models as compared with those of children in both lateral and frontal exposures. Maximum <span class="hlt">SAR</span> values calculated in lateral exposure are significantly lower than those calculated in frontal exposure, where the EAS-body distance is shorter. Nevertheless, in all studied cases, with an EAS driving current of 4 A rms, maximum induced current and <span class="hlt">SAR</span> values are below basic restrictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16455589','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16455589"><span id="translatedtitle">The in vitro permeability coefficient and short-term <span class="hlt">absorption</span> <span class="hlt">rates</span> for vinyl toluene using human cadaver skin mounted in a static diffusion cell model.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fasano, William J; Baer, Kevin N</p> <p>2006-01-01</p> <p>Vinyl toluene is one of several methylstyrene monomers that provide improved performance in resins for specialty paints, hydrocarbon resins for adhesives, specialty polymers, and unsaturated polyester resins. The purpose of this study was to determine a permeability coefficient (Kp) and short-term <span class="hlt">absorption</span> <span class="hlt">rate</span> for vinyl toluene using human cadaver skin mounted in an in vitro static diffusion cell model with an exposure area of 0.64 cm2. For the Kp determination, vinyl toluene was applied at a <span class="hlt">rate</span> of 100 microL/cm2 to 6 skin replicates representing 4 human subjects. Serial receptor fluid samples were collected at 1, 2, 4, 8, 12, 24, 36, and 48 h postapplication and analyzed for vinyl toluene by HPLC-UV. Based on the slope at steady-state (203.3 microg cm(-2) h(-1) +/- 120.0 microg cm(-2) h(-1)) and the concentration of the applied dose of vinyl toluene, taken as its density (894,600 microg/cm3), the Kp was calculated to be 2.27 x 10(-4) cm/h (+/-1.34 x 10(-4) cm/h). For the short-term <span class="hlt">absorption</span> experiments, 12 skin replicates representing 3 human subjects were employed. Following 10- and 60-min exposures to a finite dose of vinyl toluene (10 microL/cm2), the respective short-term <span class="hlt">absorption</span> <span class="hlt">rates</span> were calculated to be 66.0 (+/-29.9) and 104.2 (+/-63.0) microg cm(-2) h(-1). These data provide industrial hygienists and safety personnel values to estimate the amount of vinyl toluene that may be absorbed via the dermal exposure route, given a variety of exposure scenarios, and the time it takes (skin <span class="hlt">absorption</span> time) to reach a body burden equal to the Occupational Safety and Health Administrative permissible exposure level (OSHA PEL) or ACGIH TLV. PMID:16455589</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/2299234','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/2299234"><span id="translatedtitle">Comparison of two-dimensional numerical approximation and measurement of <span class="hlt">SAR</span> in a muscle equivalent phantom exposed to a 915 MHz slab-loaded waveguide.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rine, G P; Samulski, T V; Grant, W; Wallen, C A</p> <p>1990-01-01</p> <p>Computer predictions of the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) distribution in a uniform muscle-equivalent phantom with an overlying bolus have been compared to those measured experimentally. The microwave source was a 10 cm x 10 cm slab-loaded waveguide applicator operating at 915 MHz. The modelling technique (theory) combines the equivalence principle and a two-dimensional finite element technique to determine the incident and the scattered electric fields separately. The E-field was measured using a small dipole device oriented parallel to the polarized field of the waveguide source. Comparisons of the predicted and measured <span class="hlt">SAR</span> were made for various bolus properties, and reasonable agreement with theory was found in each case. The results demonstrate the usefulness of numerical modelling in characterizing the fields from microwave applicators used in clinical hyperthermia. PMID:2299234</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840008338&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsars','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840008338&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsars"><span id="translatedtitle">Processor architecture for airborne <span class="hlt">SAR</span> systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Glass, C. M.</p> <p>1983-01-01</p> <p>Digital processors for spaceborne imaging radars and application of the technology developed for airborne <span class="hlt">SAR</span> systems are considered. Transferring algorithms and implementation techniques from airborne to spaceborne <span class="hlt">SAR</span> processors offers obvious advantages. The following topics are discussed: (1) a quantification of the differences in processing algorithms for airborne and spaceborne <span class="hlt">SARs</span>; and (2) an overview of three processors for airborne <span class="hlt">SAR</span> systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/920461','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/920461"><span id="translatedtitle">Anatomy of a <span class="hlt">SAR</span> impulse response.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Doerry, Armin Walter</p> <p>2007-08-01</p> <p>A principal measure of Synthetic Aperture Radar (<span class="hlt">SAR</span>) image quality is the manifestation in the <span class="hlt">SAR</span> image of a spatial impulse, that is, the <span class="hlt">SAR</span>'s Impulse Response (IPR). IPR requirements direct certain design decisions in a <span class="hlt">SAR</span>. Anomalies in the IPR can point to specific anomalous behavior in the radar's hardware and/or software.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PMB....54.3393L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PMB....54.3393L"><span id="translatedtitle">Assessment of the computational uncertainty of temperature rise and <span class="hlt">SAR</span> in the eyes and brain under far-field exposure from 1 to 10 GHz</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laakso, Ilkka</p> <p>2009-06-01</p> <p>This paper presents finite-difference time-domain (FDTD) calculations of specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) values in the head under plane-wave exposure from 1 to 10 GHz using a resolution of 0.5 mm in adult male and female voxel models. Temperature rise due to the power <span class="hlt">absorption</span> is calculated by the bioheat equation using a multigrid method solver. The computational accuracy is investigated by repeating the calculations with resolutions of 1 mm and 2 mm and comparing the results. Cubically averaged 10 g <span class="hlt">SAR</span> in the eyes and brain and eye-averaged <span class="hlt">SAR</span> are calculated and compared to the corresponding temperature rise as well as the recommended limits for exposure. The results suggest that 2 mm resolution should only be used for frequencies smaller than 2.5 GHz, and 1 mm resolution only under 5 GHz. Morphological differences in models seemed to be an important cause of variation: differences in results between the two different models were usually larger than the computational error due to the grid resolution, and larger than the difference between the results for open and closed eyes. Limiting the incident plane-wave power density to smaller than 100 W m-2 was sufficient for ensuring that the temperature rise in the eyes and brain were less than 1 °C in the whole frequency range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21571541','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21571541"><span id="translatedtitle">The impact of cell-specific <span class="hlt">absorption</span> properties on the correlation of electron transport <span class="hlt">rates</span> measured by chlorophyll fluorescence and photosynthetic oxygen production in planktonic algae.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Blache, Ulrich; Jakob, Torsten; Su, Wanwen; Wilhelm, Christian</p> <p>2011-08-01</p> <p>Photosynthesis-irradiance (P-E)-curves describe the photosynthetic performance of autotrophic organisms. From these P-E-curves the photosynthetic parameters α-slope, P(max), and E(k) can be deduced which are often used to characterize and to compare different organisms or organisms in acclimation to different environmental conditions. Particularly, for in situ-measurements of P-E curves of phytoplankton the analysis of variable chlorophyll fluorescence proved its potential as a sensitive and rapid method. By using Chlorella vulgaris (Trebouxiophyceae), Nannochloropsis salina (Eustigmatophyceae), Skeletonema costatum and Cyclotella meneghiniana (Bacillariophyceae), the present study investigated the influence of cellular bio-optical properties on the correlation of the photosynthetic parameters derived from fluorescence-based P-E-curves with photosynthetic parameters obtained from the measurement of oxygen evolution. It is demonstrated that small planktonic algae show a wide range of cellular <span class="hlt">absorptivity</span> which was subject to species-specifity, growth stage and environmental conditions, e.g. nutrient limitation. This variability in bio-optical properties resulted in a great deviation of relative electron transport <span class="hlt">rates</span> (rETRs) from oxygen-based photosynthesis <span class="hlt">rates</span>. Thus, the photosynthetic parameters α-slope and P(max) derived from rETRs strongly depend on the specific cellular <span class="hlt">absorptivity</span> and cannot be used to compare the photosynthetic performance of cells with different optical properties. However, it was shown that E(k) is independent of cellular <span class="hlt">absorptivity</span> and could be used to compare samples with unknown optical properties. PMID:21571541</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910031344&hterms=hydrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhydrology','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910031344&hterms=hydrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhydrology"><span id="translatedtitle">Studies of ice sheet hydrology using <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bindschadler, R. A.; Vornberger, P. L.</p> <p>1989-01-01</p> <p>Analysis of <span class="hlt">SAR</span> data of the Greenland ice sheet in summer and winter suggest the use of <span class="hlt">SAR</span> to monitor the temporal hydrology of ice sheets. Comparisons of each <span class="hlt">SAR</span> data set with summer Landsat TM imagery show an areal-positive correlation with summer <span class="hlt">SAR</span> data and a negative correlation with winter <span class="hlt">SAR</span> data. It is proposed that the summer <span class="hlt">SAR</span> data are most sensitive to the variable concentrations of free water in the surface snow and that the winter <span class="hlt">SAR</span> data indicate variations in snow grain size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5078361','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5078361"><span id="translatedtitle">Comparison of whole-body specific <span class="hlt">absorption</span> <span class="hlt">rate</span> for human phantoms with and without skeletal features. Final report, 1 January-31 December 1985</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hurt, W.D.</p> <p>1986-05-01</p> <p>The most common biological effect of overexposure to radiofrequency radiation (RFR) fields may be described as an acute thermal burden. The extent of the effect depends primarily on the time <span class="hlt">rate</span> of transfer of the energy to the biological specimen. The depth of penetration and the amount of incident energy absorbed varies as a function of the frequency of the incident radiation. As the frequency decreases, the penetration of energy into biological tissue becomes deeper; however, wavelengths in the kilohertz (kHz) and lower megahertz (MHz) regions are so long with respect to the physical dimensions of the human subject that energy <span class="hlt">absorption</span> is negligible. The purpose of this research was to measure the energy <span class="hlt">absorption</span> in human phantoms when exposed to high-frequency (HF) band fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22724310S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22724310S"><span id="translatedtitle">Intrinsic <span class="hlt">Absorption</span> in Quasars (AAL & BAL) and its Relation to Outflows, BH Mass, Accretion <span class="hlt">Rate</span>, Spin, Orientation, and Radio Properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stone, Robert Bernard; Richards, Gordon T.</p> <p>2016-01-01</p> <p>Despite the fact that quasars are fueled by matter falling into supermassive black holes, this process spews out considerable mass and energy. We investigate the nature of these outflows in the form of both broad and narrow <span class="hlt">absorption</span> lines using data taken as part of the Sloan Digital Sky Survey (SDSS). Although these outflows are seen to have ejection speeds of up to 60,000 km/s, it is still unclear how they affect the quasar's host-galaxy and its evolution. We look for correlations of these outflows with the radio properties of the quasars, which can potentially reveal a physical connection between the quasar's accretion physics and its outflows. We also investigate how relaxing the traditional criteria for defining both radio loud and broad <span class="hlt">absorption</span> line quasars impacts our understanding of these classes and quasars in general. Our ultimate goal is to understand how outflows from quasars change as a function of line-of-sight orientation, mass, accretion, and spin of the black holes that fuel them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16460760','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16460760"><span id="translatedtitle">Prevalence of psychiatric morbidity and psychological adaptation of the nurses in a structured <span class="hlt">SARS</span> caring unit during outbreak: a prospective and periodic assessment study in Taiwan.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Su, Tung-Ping; Lien, Te-Cheng; Yang, Chih-Yi; Su, Yiet Ling; Wang, Jia-Horng; Tsai, Sing-Ling; Yin, Jeo-Chen</p> <p>2007-01-01</p> <p>To assess the rapidly changing psychological status of nurses during the acute phase of the 2003 <span class="hlt">SARS</span> outbreak, we conducted a prospective and periodic evaluation of psychiatric morbidity and psychological adaptation among nurses in <span class="hlt">SARS</span> units and non-<span class="hlt">SARS</span> units. Nurse participants were from two <span class="hlt">SARS</span> units (regular <span class="hlt">SARS</span> [N=44] and <span class="hlt">SARS</span> ICU [N=26]) and two non-<span class="hlt">SARS</span> units (Neurology [N=15] and CCU [N=17]). Participants periodically self-evaluated their depression, anxiety, post-traumatic stress symptoms, sleep disturbance, attitude towards <span class="hlt">SARS</span> and family support. Results showed that depression (38.5% vs. 3.1%) and insomnia (37% vs. 9.7%) were, respectively, greater in the <span class="hlt">SARS</span> unit nurses than the non-<span class="hlt">SARS</span> unit nurses. No difference between these two groups was found in the prevalence of post-traumatic stress symptoms (33% vs. 18.7%), yet, three unit subjects (<span class="hlt">SARS</span> ICU, <span class="hlt">SARS</span> regular and Neurology) had significantly higher <span class="hlt">rate</span> than those in CCU (29.7% vs. 11.8%, respectively) (p<0.05). For the <span class="hlt">SARS</span> unit nurses, significant reduction in mood <span class="hlt">ratings</span>, insomnia <span class="hlt">rate</span> and perceived negative feelings as well as increasing knowledge and understanding of <span class="hlt">SARS</span> at the end of the study (all p<0.001) indicated that a gradual psychological adaptation had occurred. The adjustment of nurses in the more structured <span class="hlt">SARS</span> ICU environment, where nurses care for even more severely ill patients, may have been as good or better than that of nurses in the regular <span class="hlt">SARS</span> unit. Occurrence of psychiatric symptoms was linked to direct exposure to <span class="hlt">SARS</span> patient care, previous mood disorder history, younger age and perceived negative feelings. Positive coping attitude and strong social and family support may have protected against acute stress. In conclusion, the psychological impact on the caring staffs facing future bio-disaster will be minimized with lowered risk factors and a safer and more structured work environment. PMID:16460760</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRE..112.3S90K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRE..112.3S90K"><span id="translatedtitle"><span class="hlt">SAR/InSAR</span> observation by an HF sounder</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kobayashi, T.; Ono, T.</p> <p>2007-03-01</p> <p>Application of <span class="hlt">SAR</span> imaging algorithm to spaceborne HF sounder observation was studied. Two types of image ambiguity problems were addressed in the application. One is surface/subsurface image ambiguity arising from deep penetration of HF wave, and another is mirror image ambiguity that is inherent to dipole antenna <span class="hlt">SAR</span>. A numerical model demonstrated that the surface/subsurface ambiguity can be mitigated by taking a synthetic aperture large enough to defocus subsurface objects. In order to resolve the mirror image ambiguity problem, an image superposition technique was proposed. The performance of the technique was demonstrated by using simulation data of the HF sounder observation to confirm the feasibility of HF <span class="hlt">SAR</span> and HF In<span class="hlt">SAR</span> observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780013624','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780013624"><span id="translatedtitle">Synthetic Aperture Radar (<span class="hlt">SAR</span>) data processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Beckner, F. L.; Ahr, H. A.; Ausherman, D. A.; Cutrona, L. J.; Francisco, S.; Harrison, R. E.; Heuser, J. S.; Jordan, R. L.; Justus, J.; Manning, B.</p> <p>1978-01-01</p> <p>The available and optimal methods for generating <span class="hlt">SAR</span> imagery for NASA applications were identified. The <span class="hlt">SAR</span> image quality and data processing requirements associated with these applications were studied. Mathematical operations and algorithms required to process sensor data into <span class="hlt">SAR</span> imagery were defined. The architecture of <span class="hlt">SAR</span> image formation processors was discussed, and technology necessary to implement the <span class="hlt">SAR</span> data processors used in both general purpose and dedicated imaging systems was addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=97966','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=97966"><span id="translatedtitle">Characterization of <span class="hlt">sar</span>R, a Modulator of <span class="hlt">sar</span> Expression in Staphylococcus aureus</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Manna, Adhar; Cheung, Ambrose L.</p> <p>2001-01-01</p> <p>The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., <span class="hlt">sar</span> and agr). The <span class="hlt">sar</span> locus is composed of three overlapping transcripts (<span class="hlt">sar</span> P1, P3, and P2 transcripts from P1, P3, and P2 promoters, respectively), all encoding the 372-bp <span class="hlt">sar</span>A gene. The level of <span class="hlt">Sar</span>A, the major regulatory protein, is partially controlled by the differential activation of <span class="hlt">sar</span> promoters. We previously partially purified a ∼12 kDa protein with a DNA-specific column containing a <span class="hlt">sar</span> P2 promoter fragment. In this study, the putative gene, designated <span class="hlt">sar</span>R, was identified and found to encode a 13.6-kDa protein with homology to <span class="hlt">Sar</span>A. Transcriptional and immunoblot studies revealed the <span class="hlt">sar</span>R gene to be expressed in other staphylococcal strains. Recombinant <span class="hlt">Sar</span>R protein bound <span class="hlt">sar</span> P1, P2, and P3 promoter fragments in gel shift and footprinting assays. A <span class="hlt">sar</span>R mutant expressed a higher level of P1 transcript than the parent, as confirmed by promoter green fluorescent protein fusion assays. As the P1 transcript is the predominant <span class="hlt">sar</span> transcript, we confirmed that the <span class="hlt">sar</span>R mutant expressed more <span class="hlt">Sar</span>A than the parental strain. We thus proposed that <span class="hlt">Sar</span>R is a regulatory protein that binds to the <span class="hlt">sar</span> promoters to down-regulate P1 transcription and the ensuing <span class="hlt">Sar</span>A protein expression. PMID:11159982</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PMB....53.1167W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PMB....53.1167W"><span id="translatedtitle">On the effects of straight metallic jewellery on the specific <span class="hlt">absorption</span> <span class="hlt">rates</span> resulting from face-illuminating radio communication devices at popular cellular frequencies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whittow, W. G.; Panagamuwa, C. J.; Edwards, R. M.; Vardaxoglou, J. C.</p> <p>2008-03-01</p> <p>This paper presents simulated and measured phantom results for the possible effects that head worn jewellery may have on the relative levels of energy absorbed in the human head with cellular enabled mobile communication devices. The FDTD electromagnetic code used with simple and complex anatomical mathematical phantoms was used to consider the interactions of metallic jewellery, heads and representative sources at 900 and 1800 MHz. Illuminated metallic pins of different lengths were positioned in front of the face. Initially, a homogenous phantom was used to understand the relative enhancement mechanisms. This geometry allowed the results to be validated with the industry standard DASY4 robot <span class="hlt">SAR</span> measurement system related to the CENELEC head. Jewellery pins were then added to an anatomically realistic head. The relative increase in the 1 g and 10 g <span class="hlt">SAR</span>, due to a pin with a length 0.4λ near the eyebrows of a complex, anatomically realistic head was approximately three times at 1800 MHz. Such pins increased the <span class="hlt">SAR</span> averaged over a 1 g or 10 g mass by redistributing the energy absorbed inside the head and focusing this energy towards the area of the head nearest to the centre of the pin. Although, the pins increased the <span class="hlt">SAR</span>, the <span class="hlt">SAR</span> standards were not breached and the jewellery produced lower values than those of previous studies when the source was positioned close to the ear.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18296756','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18296756"><span id="translatedtitle">On the effects of straight metallic jewellery on the specific <span class="hlt">absorption</span> <span class="hlt">rates</span> resulting from face-illuminating radio communication devices at popular cellular frequencies.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Whittow, W G; Panagamuwa, C J; Edwards, R M; Vardaxoglou, J C</p> <p>2008-03-01</p> <p>This paper presents simulated and measured phantom results for the possible effects that head worn jewellery may have on the relative levels of energy absorbed in the human head with cellular enabled mobile communication devices. The FDTD electromagnetic code used with simple and complex anatomical mathematical phantoms was used to consider the interactions of metallic jewellery, heads and representative sources at 900 and 1800 MHz. Illuminated metallic pins of different lengths were positioned in front of the face. Initially, a homogenous phantom was used to understand the relative enhancement mechanisms. This geometry allowed the results to be validated with the industry standard DASY4 robot <span class="hlt">SAR</span> measurement system related to the CENELEC head. Jewellery pins were then added to an anatomically realistic head. The relative increase in the 1 g and 10 g <span class="hlt">SAR</span>, due to a pin with a length 0.4lambda near the eyebrows of a complex, anatomically realistic head was approximately three times at 1800 MHz. Such pins increased the <span class="hlt">SAR</span> averaged over a 1 g or 10 g mass by redistributing the energy absorbed inside the head and focusing this energy towards the area of the head nearest to the centre of the pin. Although, the pins increased the <span class="hlt">SAR</span>, the <span class="hlt">SAR</span> standards were not breached and the jewellery produced lower values than those of previous studies when the source was positioned close to the ear. PMID:18296756</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ESASP.697E...8A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ESASP.697E...8A"><span id="translatedtitle">Polarimetric <span class="hlt">SAR</span> Tomopgraphy With Terra<span class="hlt">SAR</span>-X By Means Of Distributed Compressed Sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aguilera, E.; Nannini, M.; Antonello, A.; Marotti, L.; Prats, P.; Reigber, A.</p> <p>2012-01-01</p> <p>In <span class="hlt">SAR</span> tomography, the vertical reflectivity function for every azimuth-range pixel is usually recovered by processing data collected using a defined repeat-pass acquisition geometry. A common and appealing approach is to generate a synthetic aperture in the elevation direction through imaging from parallel tracks. However, the quality of conventional reconstruction methods is generally dictated by the Nyquist <span class="hlt">rate</span>, which can be considerably high. In an attempt to reduce this <span class="hlt">rate</span>, we propose a new tomographic focusing approach that exploits correlations between neighboring azimuth-range pixels and polarimetric channels. As a matter of fact, this can be done under the framework of Distributed Com- pressed Sensing (DCS), which stems from Compressed Sensing (CS) theory, thus also exploiting sparsity in the tomographic signal. Results demonstrating the potential of the DCS methodology will be validated, for the first time, using dual-polarized data acquired at X-band by the Terra<span class="hlt">SAR</span>-X spaceborne system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT........53F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT........53F"><span id="translatedtitle">Geodetic imaging of tectonic deformation with In<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fattahi, Heresh</p> <p></p> <p>Precise measurements of ground deformation across the plate boundaries are crucial observations to evaluate the location of strain localization and to understand the pattern of strain accumulation at depth. Such information can be used to evaluate the possible location and magnitude of future earthquakes. Interferometric Synthetic Aperture Radar (In<span class="hlt">SAR</span>) potentially can deliver small-scale (few mm/yr) ground displacement over long distances (hundreds of kilometers) across the plate boundaries and over continents. However, Given the ground displacement as our signal of interest, the In<span class="hlt">SAR</span> observations of ground deformation are usually affected by several sources of systematic and random noises. In this dissertation I identify several sources of systematic and random noise, develop new methods to model and mitigate the systematic noise and to evaluate the uncertainty of the ground displacement measured with In<span class="hlt">SAR</span>. I use the developed approach to characterize the tectonic deformation and evaluate the <span class="hlt">rate</span> of strain accumulation along the Chaman fault system, the western boundary of the India with Eurasia tectonic plates. I evaluate the bias due to the topographic residuals in the In<span class="hlt">SAR</span> range-change time-series and develope a new method to estimate the topographic residuals and mitigate the effect from the In<span class="hlt">SAR</span> range-change time-series (Chapter 2). I develop a new method to evaluate the uncertainty of the In<span class="hlt">SAR</span> velocity field due to the uncertainty of the satellite orbits (Chapter 3) and a new algorithm to automatically detect and correct the phase unwrapping errors in a dense network of interferograms (Chapter 4). I develop a new approach to evaluate the impact of systematic and stochastic components of the tropospheric delay on the In<span class="hlt">SAR</span> displacement time-series and its uncertainty (Chapter 5). Using the new In<span class="hlt">SAR</span> time-series approach developed in the previous chapters, I study the tectonic deformation across the western boundary of the India plate with Eurasia and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920029916&hterms=The+Jet+Propulsion+Laboratory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528%2528%2528The%2BJet%2529%2BPropulsion%2529%2BLaboratory%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920029916&hterms=The+Jet+Propulsion+Laboratory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528%2528%2528The%2BJet%2529%2BPropulsion%2529%2BLaboratory%2529"><span id="translatedtitle">Earth observing <span class="hlt">SAR</span> data processing systems at the Jet Propulsion Laboratory - Seasat to EOS <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nichols, David A.; Curlander, John C.</p> <p>1991-01-01</p> <p>The evolution of <span class="hlt">SAR</span> digital data processing and management ground systems developed at the JPL for earth science missions is discussed. Attention is given to the <span class="hlt">SAR</span> ground data system requirements, the early data processing systems, the Seasat <span class="hlt">SAR</span> system, and the SIR-B data processing system. Special consideration is given to two currently operational <span class="hlt">SAR</span> data systems: the JPL aircraft <span class="hlt">SAR</span> processing system that flies on the NASA DC-8 and the Alaska <span class="hlt">SAR</span> Facility at Fairbanks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918586','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4918586"><span id="translatedtitle">Dynamic <span class="hlt">absorption</span> and scattering of water and hydrogel during high-repetition-<span class="hlt">rate</span> (>100 MHz) burst-mode ultrafast-pulse laser ablation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Qian, Zuoming; Covarrubias, Andrés; Grindal, Alexander W.; Akens, Margarete K.; Lilge, Lothar; Marjoribanks, Robin S.</p> <p>2016-01-01</p> <p>High-repetition-<span class="hlt">rate</span> burst-mode ultrafast-laser ablation and disruption of biological tissues depends on interaction of each pulse with the sample, but under those particular conditions which persist from previous pulses. This work characterizes and compares the dynamics of <span class="hlt">absorption</span> and scattering of a 133-MHz repetition-<span class="hlt">rate</span>, burst-mode ultrafast-pulse laser, in agar hydrogel targets and distilled water. The differences in energy partition are quantified, pulse-by-pulse, using a time-resolving integrating-sphere-based device. These measurements reveal that high-repetition-<span class="hlt">rate</span> burst-mode ultrafast-laser ablation is a highly dynamical process affected by the persistence of ionization, dissipation of plasma plume, neutral material flow, tissue tensile strength, and the hydrodynamic oscillation of cavitation bubbles. PMID:27375948</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27375948','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27375948"><span id="translatedtitle">Dynamic <span class="hlt">absorption</span> and scattering of water and hydrogel during high-repetition-<span class="hlt">rate</span> (>100 MHz) burst-mode ultrafast-pulse laser ablation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qian, Zuoming; Covarrubias, Andrés; Grindal, Alexander W; Akens, Margarete K; Lilge, Lothar; Marjoribanks, Robin S</p> <p>2016-06-01</p> <p>High-repetition-<span class="hlt">rate</span> burst-mode ultrafast-laser ablation and disruption of biological tissues depends on interaction of each pulse with the sample, but under those particular conditions which persist from previous pulses. This work characterizes and compares the dynamics of <span class="hlt">absorption</span> and scattering of a 133-MHz repetition-<span class="hlt">rate</span>, burst-mode ultrafast-pulse laser, in agar hydrogel targets and distilled water. The differences in energy partition are quantified, pulse-by-pulse, using a time-resolving integrating-sphere-based device. These measurements reveal that high-repetition-<span class="hlt">rate</span> burst-mode ultrafast-laser ablation is a highly dynamical process affected by the persistence of ionization, dissipation of plasma plume, neutral material flow, tissue tensile strength, and the hydrodynamic oscillation of cavitation bubbles. PMID:27375948</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820036513&hterms=listening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dlistening','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820036513&hterms=listening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dlistening"><span id="translatedtitle"><span class="hlt">SAR</span> imaging - Seeing the unseen</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kobrick, M.</p> <p>1982-01-01</p> <p>The functional abilities and operations of synthetic aperture radar (<span class="hlt">SAR</span>) are described. <span class="hlt">SAR</span> employs long wavelength radio waves in bursts, imaging a target by 'listening' to the small frequency changes that result from the Doppler shift due to the relative motion of the imaging craft and the motions of the target. The time delay of the signal return allows a determination of the location of the target, leading to the build up of a two-dimensional image. The uses of both Doppler shifts and time delay enable detailed imagery which is independent of distance. The synthetic aperture part of the name of <span class="hlt">SAR</span> derives from the beaming of multiple pulses, which result in a picture that is effectively the same as using a large antenna. Mechanisms contributing to the fineness of <span class="hlt">SAR</span> images are outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3320307','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3320307"><span id="translatedtitle"><span class="hlt">SARS</span> Antibody Test for Serosurveillance</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hsueh, Po-Ren; Kao, Chuan-Liang; Lee, Chun-Nan; Chen, Li-Kuan; Ho, Mei-Shang; Sia, Charles; De Fang, Xin; Lynn, Shugene; Chang, Tseng Yuan; Liu, Shi Kau; Walfield, Alan M.</p> <p>2004-01-01</p> <p>A peptide-based enzyme-linked immunosorbent assay (ELISA) can be used for retrospective serosurveillance of severe acute respiratory syndrome (<span class="hlt">SARS</span>) by helping identify undetected chains of disease transmission. The assay was developed by epitope mapping, using synthetic peptides from the spike, membrane, and nucleocapsid protein sequences of <span class="hlt">SARS</span>-associated coronavirus. The new peptide ELISA consistently detected seroconversion by week 2 of onset of fever, and seropositivity remained through day 100. Specificity was 100% on normal blood donor samples, on serum samples associated with infection by other pathogens, and on an interference panel. The peptide-based test has advantages of safety, standardization, and automation over previous immunoassays for <span class="hlt">SARS</span>. The assay was used for a retrospective survey of healthy healthcare workers in Taiwan who treated <span class="hlt">SARS</span> patients. Asymptomatic seroconversions were detected in two hospitals that had nosocomial disease. PMID:15498156</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMNH51C..05F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMNH51C..05F"><span id="translatedtitle">Landslide Mapping Using Squee<span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferretti, A.; Bellotti, F.; Alberti, S.; Allievi, J.; Del Conte, S.; Tamburini, A.; Broccolato, M.; Ratto, S.; Alberto, W.</p> <p>2011-12-01</p> <p>Squee<span class="hlt">SAR</span> represents the most recent advancement of PSIn<span class="hlt">SAR</span> algorithm. By exploiting signal radar returns both from Permanent and Distributed Scatterers (PS and DS), it is able to detect millimetre displacements over long periods and large areas and to obtain a significant increase in the spatial density of ground measurement points. Squee<span class="hlt">SAR</span> analysis is complementary to conventional geological and geomorphological studies in landslide mapping over wide areas, traditionally based on aerial-photo interpretation and field surveys. However, whenever surface displacement <span class="hlt">rates</span> are low (mm to cm per year), assessing landslide activity is difficult or even impossible without a long-term monitoring tool, as in the case of Deep-seated Gravitational Slope Deformations (DGSD), typically characterized by large areal extent and subtle surface displacement. The availability of surface displacement time series per each measurement point allows one to have both a synoptic overview, at regional scale, as well as an in depth characterization of the instability phenomena analyzed, a meaningful support to the design of traditional monitoring networks and the efficiency testing of remedial works. When data archives are available, Squee<span class="hlt">SAR</span> can also provide valuable information before the installation of any terrestrial measurement system. The Italian authorities increasing interest in the application of Squee<span class="hlt">SAR</span> as a standard monitoring tool to help hydrogeological risk assessment, resulted in a national project, Piano Straordinario di Telerilevamento (PST), founded by the Ministry of the Environment. The aim of the project was to create the first interferometric database on a national scale for mapping unstable areas. More than 12,000 ERS and ENVISAT radar scenes acquired over Italy were processed spanning the period 1992-2010, proving that, in less than ten years, radar interferometry has become a standard monitoring tool. Recently, many regional governments in Italy have applied</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SPIE.5236....9W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SPIE.5236....9W"><span id="translatedtitle">Terra<span class="hlt">SAR</span>-X mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werninghaus, Rolf</p> <p>2004-01-01</p> <p>The Terra<span class="hlt">SAR</span>-X is a German national <span class="hlt">SAR</span>- satellite system for scientific and commercial applications. It is the continuation of the scientifically and technologically successful radar missions X-<span class="hlt">SAR</span> (1994) and SRTM (2000) and will bring the national technology developments DESA and TOPAS into operational use. The space segment of Terra<span class="hlt">SAR</span>-X is an advanced high-resolution X-Band radar satellite. The system design is based on a sound market analysis performed by Infoterra. The Terra<span class="hlt">SAR</span>-X features an advanced high-resolution X-Band Synthetic Aperture Radar based on the active phased array technology which allows the operation in Spotlight-, Stripmap- and Scan<span class="hlt">SAR</span> Mode with various polarizations. It combines the ability to acquire high resolution images for detailed analysis as well as wide swath images for overview applications. In addition, experimental modes like the Dual Receive Antenna Mode allow for full-polarimetric imaging as well as along track interferometry, i.e. moving target identification. The Ground Segment is optimized for flexible response to (scientific and commercial) User requests and fast image product turn-around times. The Terra<span class="hlt">SAR</span>-X mission will serve two main goals. The first goal is to provide the strongly supportive scientific community with multi-mode X-Band <span class="hlt">SAR</span> data. The broad spectrum of scientific application areas include Hydrology, Geology, Climatology, Oceanography, Environmental Monitoring and Disaster Monitoring as well as Cartography (DEM Generation) and Interferometry. The second goal is the establishment of a commercial EO-market in Europe which is driven by Infoterra. The commercial goal is the development of a sustainable EO-business so that the e.g. follow-on systems can be completely financed by industry from the profit. Due to its commercial potential, the Terra<span class="hlt">SAR</span>-X project will be implemented based on a public-private partnership with the Astrium GmbH. This paper will describe first the mission objectives as well as the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JMagR.185...94M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JMagR.185...94M"><span id="translatedtitle">Nonlinear magnetic field gradients can reduce <span class="hlt">SAR</span> in flow-driven arterial spin labeling measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marro, Kenneth I.; Lee, Donghoon; Hyyti, Outi M.</p> <p>2007-03-01</p> <p>This work describes how custom-built gradient coils, designed to generate magnetic fields with amplitudes that vary nonlinearly with position, can be used to reduce the potential for unsafe tissue heating during flow-driven arterial spin labeling processes. A model was developed to allow detailed analysis of the adiabatic excitation process used for flow-driven arterial water stimulation with elimination of tissue signal (FAWSETS) an arterial spin labeling method developed specifically for use in skeletal muscle. The model predicted that, by adjusting the amplitude of the gradient field, the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> could be reduced by more than a factor of 6 while still achieving effective labeling. Flow phantom measurements and in vivo measurements from exercising rat hind limb confirmed the accuracy of the model's predictions. The modeling tools were also applied to the more widely used continuous arterial spin labeling (CASL) method and predicted that specially shaped gradients could allow similar reductions in <span class="hlt">SAR</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PMB....48.3263A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PMB....48.3263A"><span id="translatedtitle">Comparisons of peak <span class="hlt">SAR</span> levels in concentric sphere head models of children and adults for irradiation by a dipole at 900 MHz</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, Vitas</p> <p>2003-10-01</p> <p>The aim of this study is to examine the scale and significance of differences in peak specific energy <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) in the brains of children and adults exposed to radiofrequency emissions from mobile phones. Estimates were obtained by method of multipole analysis of a three layered (scalp/cranium/brain) spherical head exposed to a nearby 0.4lgr dipole at 900 MHz. A literature review of head parameters that influence <span class="hlt">SAR</span> induction revealed strong indirect evidence based on total body water content that there are no substantive age-related changes in tissue conductivity after the first year of life. However, it was also found that the thickness of the ear, scalp and cranium do decrease on average with decreasing age, though individual variability within any age group is very high. The model analyses revealed that compared to an average adult, the peak brain 10 g averaged <span class="hlt">SAR</span> in mean 4, 8, 12 and 16 year olds (yo) is increased by a factor of 1.31, 1.23, 1.15 and 1.07, respectively. However, contrary to the expectations of a recent prominent expert review, the UK Stewart Report, the relatively small scale of these increases does not warrant any special precautionary measures for child mobile phone users since: (a) <span class="hlt">SAR</span> testing protocols as contained in the CENELEC (2001) standard provide an additional safety margin which ensures that allowable localized <span class="hlt">SAR</span> limits are not exceeded in the brain; (b) the maximum worst case brain temperature rise (~0.13 to 0.14 °C for an average 4 yo) in child users of mobile phones is well within safe levels and normal physiological parameters; and (c) the range of age average increases in children is less than the expected range of variation seen within the adult population.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870007729','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870007729"><span id="translatedtitle">The X-<span class="hlt">SAR</span> System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oettl, Herwig</p> <p>1986-01-01</p> <p>During the past few years, there has been significant progress made in the planning for an X-band <span class="hlt">SAR</span>, designed to fly in the shuttle together with the SIR-C system of NASA/JPL. New work and studies have been initiated to enable the goal of two missions in 1990 to be met. The antennas of X-<span class="hlt">SAR</span> and SIR-C will be placed side-by-side on a pivoted steerable foldable structure, which will allow antenna movement without changing the attitude of the shuttle. This figure also shows the pallet, underneath the antenna structure, which houses the electronic sub-systems of both radars. Although the two radar systems, X-band <span class="hlt">SAR</span> and the L- and C-band <span class="hlt">SAR</span> of SIR-C, have different technical designs, their overall system performance, in terms of image quality, is expected to be similar. The current predicted performance of the X-<span class="hlt">SAR</span> system based on results of the continuing Phase B studies is detailed. Differences between the performance parameters of X-<span class="hlt">SAR</span> and those of SIR-C are only detailed in as far as they affect planning decisions to be made by experimenters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26652424','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26652424"><span id="translatedtitle">In vitro hyperthermia with improved colloidal stability and enhanced <span class="hlt">SAR</span> of magnetic core/shell nanostructures.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patil, R M; Thorat, N D; Shete, P B; Otari, S V; Tiwale, B M; Pawar, S H</p> <p>2016-02-01</p> <p>Magnetic core/shell nanostructures of Fe3O4 nanoparticles coated with oleic acid and betaine-HCl were studied for their possible use in magnetic fluid hyperthermia (MFH). Their colloidal stability and heat induction ability were studied in different media viz. phosphate buffer solution (PBS), saline solution and glucose solution with different physiological conditions and in human serum. The results showed enhanced colloidal stability in these media owing to their high zeta potential values. Heat induction studies showed that specific <span class="hlt">absorption</span> <span class="hlt">rates</span> (<span class="hlt">SAR</span>) of core/shells were 82-94W/g at different pH of PBS and concentrations of NaCl and glucose. Interestingly, core/shells showed 78.45±3.90W/g <span class="hlt">SAR</span> in human serum. The cytotoxicity of core/shells done on L929 and HeLa cell lines using 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide and trypan blue dye exclusion assays showed >89% and >80% cell viability for 24 and 48h respectively. Core/shell structures were also found to be very efficient for in vitro MFH on cancer cell line. About 95% cell death was occurred in 90min after hyperthermia treatment. The mechanism of cell death was found to be elevated ROS generation in cells after exposure to core/shells in external magnetic field. This study showed that these core/shells have a great potential to be used in in vivo MFH. PMID:26652424</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013OptCo.294..250K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013OptCo.294..250K"><span id="translatedtitle">High energy, low repetition <span class="hlt">rate</span>, photonic crystal fiber generated supercontinuum for nanosecond to millisecond transient <span class="hlt">absorption</span> spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kho, Julie L. H.; Rohde, Charles A.; Vanholsbeeck, Frédérique; Cather Simpson, M.</p> <p>2013-05-01</p> <p>High energy density per pulse (-15 dBm nm-1) supercontinuum (SC) source has been developed as a probe for transient <span class="hlt">absorption</span> (TrA) spectroscopy of systems with lifetimes from nanoseconds to a few milliseconds. We have generated a 600-1600 nm, broadband SC by pumping a 15 m photonic crystal fiber (PCF) with relatively high power, 7 ns, 1064 nm pulses. The SC generated at peak pump power of 7.1 kW was randomly polarized and maintained a stable output (6.5% rms average power; 9.1% rms shot-to-shot power). Co-pumping with both 1064 and 532 nm light extended the wavelength range of the SC by about 20%, to 500-1700 nm. Power conversion efficiency and spectral flatness were improved as well. In the visible range, the single-pump SC shows a flatness of 5 dB while the dual-pump SC exhibits 3 dB. In the NIR (1100-1600 nm), the flatness in single- and dual-pump configurations were 3 and 2 dB, respectively. Optically induced fiber breakdown was characterized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ASAJ..118R1925S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ASAJ..118R1925S"><span id="translatedtitle">The effects of receiving room dimensions and <span class="hlt">absorption</span> in the measurement of impact insulation class (IIC) <span class="hlt">rating</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Rose Mary; Tocci, Gregory</p> <p>2005-09-01</p> <p>The measurement of the Impact Insulation Class (IIC) <span class="hlt">rating</span> of any floor/ceiling construction requires the use of a certified laboratory space. In a recent investigation into the IIC <span class="hlt">rating</span> of a new floor system, several tests were conducted in a certified laboratory. In many tests, the IIC <span class="hlt">rating</span> was controlled by the 100-Hz 1/3-octave frequency band, despite changes in the floor/ceiling construction. The base floor/ceiling construction included a wood structural floor on open-web wood joists and a GWB ceiling below. This paper will investigate the possibility that room resonances influenced the IIC <span class="hlt">ratings</span> of the several floor systems tested. These data will be compared with IIC data collected for the same floor construction with the GWB ceiling removed. The removal of the GWB ceiling increased the receiver room volume and exposed the glass fiber insulation to the receiver room, thus eliminating the control of the 100-Hz 1/3-octave band over the IIC <span class="hlt">rating</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21964524','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21964524"><span id="translatedtitle">Local <span class="hlt">SAR</span> enhancements in anatomically correct children and adult models as a function of position within 1.5 T MR body coil.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Murbach, Manuel; Cabot, Eugenia; Neufeld, Esra; Gosselin, Marie-Christine; Christ, Andreas; Pruessmann, Klaas P; Kuster, Niels</p> <p>2011-12-01</p> <p>Usage of magnetic resonance imaging (MRI) is continuously increasing due to its excellent soft-tissue contrast and improving diagnostic values. MRI also has the advantage that it operates without ionizing radiation. The main safety concerns are torque, acceleration by the static field, nerve stimulation by the gradient fields, and tissue heating by the radio-frequency (RF) fields. This paper investigates if children and fetuses are at higher risks than adults when the current RF regulations are applied. We analyzed and compared local <span class="hlt">absorption</span> hotspots, i.e., the peak spatial specific <span class="hlt">absorption</span> <span class="hlt">rate</span> averaged over any 10 g (ps<span class="hlt">SAR</span>10g) for five adults, three children of ages 5, 11 and 14 years, and 1 pregnant female (36 weeks' gestation) in 10 different Z-positions (head to calves). In the First Level Operating Mode (4 W/kg whole-body averaged exposure), the ps<span class="hlt">SAR</span>10g values found for adults were as large as 60 W/kg in the trunk and 104 W/kg in the extremities. The corresponding values for children were 43 and 58 W/kg, respectively, and 14 W/kg for the unborn child. Modeling of worst case anatomical RF loops can substantially increase the ps<span class="hlt">SAR</span>10g values, i.e., by factor >2. The results suggest that local exposure for children and fetuses is smaller than for adults (15-75%), i.e., no special considerations for children and the unborn child are needed regarding ps<span class="hlt">SAR</span>10g due to RF. However, the local thermal load of the unborn may be significantly increased due to the high exposure average (up to 4 W/kg) of the non-perfused amniotic fluid. PMID:21964524</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16625834','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16625834"><span id="translatedtitle">Polymorphism of <span class="hlt">SARS</span>-CoV genomes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shang, Lei; Qi, Yan; Bao, Qi-Yu; Tian, Wei; Xu, Jian-Cheng; Feng, Ming-Guang; Yang, Huan-Ming</p> <p>2006-04-01</p> <p>In this work, severe acute respiratory syndrome associated coronavirus (<span class="hlt">SARS</span>-CoV) genome BJ202 (AY864806) was completely sequenced. The genome was directly accessed from the stool sample of a patient in Beijing. Comparative genomics methods were used to analyze the sequence variations of 116 <span class="hlt">SARS</span>-CoV genomes (including BJ202) available in the NCBI GenBank. With the genome sequence of GZ02 as the reference, there were 41 polymorphic sites identified in BJ202 and a total of 278 polymorphic sites present in at least two of the 116 genomes. The distribution of the polymorphic sites was biased over the whole genome. Nearly half of the variations (50.4%, 140/278) clustered in the one third of the whole genome at the 3' end (19.0 kb-29.7 kb). Regions encoding Orf10-11, Orf3/4, E, M and S protein had the highest mutation <span class="hlt">rates</span>. A total of 15 PCR products (about 6.0 kb of the genome) including 11 fragments containing 12 known polymorphic sites and 4 fragments without identified polymorphic sites were cloned and sequenced. Results showed that 3 unique polymorphic sites of BJ202 (positions 13 804, 15 031 and 20 792) along with 3 other polymorphic sites (26 428, 26 477 and 27 243) all contained 2 kinds of nucleotides. It is interesting to find that position 18379 which has not been identified to be polymorphic in any of the other 115 published <span class="hlt">SARS</span>-CoV genomes is actually a polymorphic site. The nucleotide composition of this site is A (8) to G (6). Among 116 <span class="hlt">SARS</span>-CoV genomes, 18 types of deletions and 2 insertions were identified. Most of them were related to a 300 bp region (27,700-28,000) which encodes parts of the putative ORF9 and ORF10-11. A phylogenetic tree illustrating the divergence of whole BJ202 genome from 115 other completely sequenced <span class="hlt">SARS</span>-CoVs was also constructed. BJ202 was phylogeneticly closer to BJ01 and LLJ-2004. PMID:16625834</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8714E..0TK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8714E..0TK"><span id="translatedtitle">Lightweight <span class="hlt">SAR</span> GMTI radar technology development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirk, John C.; Lin, Kai; Gray, Andrew; Hseih, Chung; Darden, Scott; Kwong, Winston; Majumder, Uttam; Scarborough, Steven</p> <p>2013-05-01</p> <p>A small and lightweight dual-channel radar has been developed for <span class="hlt">SAR</span> data collections. Using standard Displaced Phase Center Antenna (DPCA) radar digital signal processing, <span class="hlt">SAR</span> GMTI images have been obtained. The prototype radar weighs 5-lbs and has demonstrated the extraction of ground moving targets (GMTs) embedded in high-resolution <span class="hlt">SAR</span> imagery data. Heretofore this type of capability has been reserved for much larger systems such as the JSTARS. Previously, small lightweight <span class="hlt">SARs</span> featured only a single channel and only displayed <span class="hlt">SAR</span> imagery. Now, with the advent of this new capability, <span class="hlt">SAR</span> GMTI performance is now possible for small UAV class radars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/653511','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/653511"><span id="translatedtitle">Diffusion coefficients significant in modeling the <span class="hlt">absorption</span> <span class="hlt">rate</span> of carbon dioxide into aqueous blends of N-methyldiethanolamine and diethanolamine and of hydrogen sulfide into aqueous N-methyldiethanolamine</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Adams, M.E.; Marshall, T.L.; Rowley, R.L.</p> <p>1998-07-01</p> <p><span class="hlt">Absorption</span> <span class="hlt">rates</span> of gaseous CO{sub 2} into aqueous blends of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) and of gaseous H{sub 2}S into aqueous MDEA were measured in a quiescent, inverted-tube diffusiometer by monitoring the <span class="hlt">rate</span> of pressure drop. A numerical model for <span class="hlt">absorption</span>, diffusion, and reaction of CO{sub 2} and H{sub 2}S in blends of MDEA, DEA, and water was developed. The model was used to regress diffusion coefficients of bicarbonate, carbamate, and MDEAH{sub 2}CO{sub 3} for the case of CO{sub 2} <span class="hlt">absorption</span> and of bisulfide ion for the case of H{sub 2}S <span class="hlt">absorption</span> from measured <span class="hlt">absorption</span> <span class="hlt">rates</span>. CO{sub 2} <span class="hlt">absorption</span> <span class="hlt">rates</span> and diffusion coefficients of bicarbonate, carbamate, and MDEAH{sub 2}CO{sub 3} were obtained at 298.2 K and 318.2 K in aqueous solutions containing 50 mass % total amine at DEA:MDEA mole ratios of 1:20, 1:4, 1L3, and 2:3. H{sub 2}S <span class="hlt">absorption</span> <span class="hlt">rates</span> and diffusion coefficients of bisulfide ion were obtained at 298.2 K and 318.2 K in aqueous solutions containing 20, 35, and 50 mass % MDEA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.664D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.664D"><span id="translatedtitle">Detection of Creep displacement along the North Anatolian Fault by Scan<span class="hlt">SAR-ScanSAR</span> Interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deguchi, Tomonori</p> <p></p> <p>North Anatolian Fault (NAF) has several records of a huge earthquake occurrence in the last one century, which is well-known as a risky active fault. Some signs indicating a creep displacement could be observed on the Ismetpasa segment. The fault with creep deformation is aseismic and never generates the large scale earthquakes. But the scale and <span class="hlt">rate</span> of fault creep are important factors to watch the fault behavior and to understand the cycle of earthquake. The author had investigated the distribution of spatial and temporal change on the ground motion due to fault creep in the surrounding of the Ismetpasa by In<span class="hlt">SAR</span> time series analysis using PALSAR datasets from 2007 until 2011. As a result, the land deformation that the northern and southern parts of the fault have slipped to east and west at a <span class="hlt">rate</span> of 7.5 and 6.5 mm/year in line of sight respectively were obviously detected. These results had good agreement with GPS data. In addition, it became clear that the fault creep along the NAF extended 61 km in east to west direction. In this study, the author applied Scan<span class="hlt">SAR-ScanSAR</span> Interferometry using PALSAR data to the Ismetpasa segment of NAF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.T33D0542C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.T33D0542C"><span id="translatedtitle">Surface deformation of Taipei basin detected by Differential <span class="hlt">SAR</span> Interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Y.; Chang, C.; Yen, J.; Lin, M.</p> <p>2006-12-01</p> <p>Taiwan island is located between the southeastern periphery of the Eurasian plate and the Philippine Sea plate. The two converging plates produced very active tectonics, and can be seen by the high seismicity and deformation <span class="hlt">rate</span>. Taipei, the highest populated area, center of politics, and economics in Taiwan, is in Taipei basin at the northern part of the island. There are several faults in and surrounding the basin, and the city is threatened with a high geological hazard potential that we should keep monitoring the crustal deformation to prevent and mitigate the disaster effect. The aims of our study is to apply the DIn<span class="hlt">SAR</span> technique to determine the surface deformation of Taipei basin area, and discussing the relation between the manifestation of deformation and the tectonically active region, Shanjiao fault. In the past few years, Differential <span class="hlt">SAR</span> Interferometry (DIn<span class="hlt">SAR</span>) has been proved to be a powerful technique for monitoring the neotectonic activities and natural hazards. High spatial sampling <span class="hlt">rate</span> of DIn<span class="hlt">SAR</span> technique allows studies of surface deformations with centimeter accuracy. In this area, we used ERS-1/2 <span class="hlt">SAR</span> images acquired from 1993 to 2005 to generate 10 differential interferograms and processed the data using DIAPASON developed by CNES and SRTM global DEM.From our results, the deformation <span class="hlt">rate</span> in Taipei is generally high in the western end of the basin along the Shanjiao fault and decrease eastward, while the subsidence center often appeared in the center of the Taipei basin. The neotectonic activity of the Shanjiao fault appeared to be insignificant by itself but it seemed to separate the subsiding basin from the surrounding areas. Further comparison between our DIn<span class="hlt">SAR</span> results and isopach of the Taipei basin revealed that the subsidence centers appeared in the interferograms did not coincide with the location where the sediments are thickest. Our results from differential interferometry will be compared to other geodetic measurements such as the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.722E.282E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.722E.282E"><span id="translatedtitle">Ten Years Of Subsidence Monitoring With <span class="hlt">SAR</span> Interferometry And Its Contribution To Risk Management In Aguascalientes, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Esquivel, Ruben; Castaneda, Laura; Taud, Hind; Lira, Jorge</p> <p>2013-12-01</p> <p>A Study involving GPS and differential <span class="hlt">SAR</span> interferometry (DIn<span class="hlt">SAR</span>) monitoring is developed to investigate a subsidence phenomenon in Aguascalientes valley and to obtain displacement models concerned with risk management applications and geodetic purposes. DIn<span class="hlt">SAR</span> study with archived Envisat data allows accumulated displacement mapping yearly, and recent Terra<span class="hlt">SAR</span>-X data implementation provides a more accurate estimation of displacements, which is used for developing models to correct geodetic positions. The maximum subsidence <span class="hlt">rate</span> calculated is 15 cm/year with a decreasing <span class="hlt">rate</span> throughout time in some areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15934785','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15934785"><span id="translatedtitle">hPEPT1 affinity and translocation of selected Gln-<span class="hlt">Sar</span> and Glu-<span class="hlt">Sar</span> dipeptide derivatives.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eriksson, André Huss; Elm, Peter L; Begtrup, Mikael; Nielsen, Robert; Steffansen, Bente; Brodin, Birger</p> <p>2005-01-01</p> <p>The intestinal di- and tripeptide transporter hPEPT1 is considered responsible for the <span class="hlt">absorption</span> of di- and tripeptides arising from digestion, along with several drugs and prodrugs. In order to gather information on the binding site of the protein, several structure-affinity relationships have been suggested. However, these are not necessarily predictive of compounds that are actually translocated by hPEPT1. More information on affinity to and translocation via hPEPT1 of side-chain-modified dipeptides may be gained by conducting a study of selected dipeptide derivatives with variety in size, hydrophobicity, and bond type. The aim of the present study was to synthesize new esters and amides based on L-Glu-<span class="hlt">Sar</span> and investigate the effects that bond type and size of modification of the N-terminal side chain of sarcosine-containing dipeptides have on the affinity to and translocation via hPEPT1. The esters L-Glu(O-i-Bu)-<span class="hlt">Sar</span> and L-Glu(OCH(2)Ada)-<span class="hlt">Sar</span> and the amides L-Gln(N,N-dimethyl)-<span class="hlt">Sar</span> and L-Gln(N-piperidinyl)-<span class="hlt">Sar</span> were synthesized, and affinity to and translocation via hPEPT1 were investigated in mature Caco-2 cell monolayers, grown on permeable supports. Affinity was estimated in a competition assay using (14)C-labeled Gly-<span class="hlt">Sar</span>. Translocation was measured as fluorescence ratios induced by the substrates using the fluorescent probe BCECF and an epifluorescence microscope setup. All compounds showed high affinity to hPEPT1, but only the amides L-Gln(N,N-dimethyl)-<span class="hlt">Sar</span> and L-Gln(N-piperidinyl)-<span class="hlt">Sar</span> were translocated by hPEPT1. hPEPT1 is very susceptible to modifications of the N-terminal amino acid side chain of dipeptidomimetic substrates, in terms of achieving compounds with high affinity for the transporter. However, as affinity is not predictive of translocation, derivatization in this position must be performed with great caution since some of the compounds investigated turn out not to be translocated by the transporter. PMID:15934785</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ESASP.724E..80C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ESASP.724E..80C&link_type=ABSTRACT"><span id="translatedtitle">Marine Targets Classification in PolIn<span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Peng; Yang, Jingsong; Ren, Lin</p> <p>2014-11-01</p> <p>In this paper, marine stationary targets and moving targets are studied by Pol-In-<span class="hlt">SAR</span> data of Radarsat-2. A new method of stationary targets detection is proposed. The method get the correlation coefficient image of the In-<span class="hlt">SAR</span> data, and using the histogram of correlation coefficient image. Then, A Constant False Alarm <span class="hlt">Rate</span> (CFAR) algorithm and The Probabilistic Neural Network model are imported to detect stationary targets. To find the moving targets, Azimuth Ambiguity is show as an important feature. We use the length of azimuth ambiguity to get the target's moving direction and speed. Make further efforts, Targets classification is studied by rebuild the surface elevation of marine targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6568E..0LM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6568E..0LM"><span id="translatedtitle"><span class="hlt">SAR</span> data exploitation: computational technology enabling <span class="hlt">SAR</span> ATR algorithm development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Majumder, Uttam K.; Casteel, Curtis H., Jr.; Buxa, Peter; Minardi, Michael J.; Zelnio, Edmund G.; Nehrbass, John W.</p> <p>2007-04-01</p> <p>A fundamental issue with synthetic aperture radar (<span class="hlt">SAR</span>) application development is data processing and exploitation in real-time or near real-time. The power of high performance computing (HPC) clusters, FPGA, and the IBM Cell processor presents new algorithm development possibilities that have not been fully leveraged. In this paper, we will illustrate the capability of <span class="hlt">SAR</span> data exploitation which was impractical over the last decade due to computing limitations. We can envision that <span class="hlt">SAR</span> imagery encompassing city size coverage at extremely high levels of fidelity could be processed at near-real time using the above technologies to empower the warfighter with access to critical information for the war on terror, homeland defense, as well as urban warfare.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9901E..0TR','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9901E..0TR"><span id="translatedtitle"><span class="hlt">SAR</span> target classification based on multiscale sparse representation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruan, Huaiyu; Zhang, Rong; Li, Jingge; Zhan, Yibing</p> <p>2016-03-01</p> <p>We propose a novel multiscale sparse representation approach for <span class="hlt">SAR</span> target classification. It firstly extracts the dense SIFT descriptors on multiple scales, then trains a global multiscale dictionary by sparse coding algorithm. After obtaining the sparse representation, the method applies spatial pyramid matching (SPM) and max pooling to summarize the features for each image. The proposed method can provide more information and descriptive ability than single-scale ones. Moreover, it costs less extra computation than existing multiscale methods which compute a dictionary for each scale. The MSTAR database and ship database collected from Terra<span class="hlt">SAR</span>-X images are used in classification setup. Results show that the best overall classification <span class="hlt">rate</span> of the proposed approach can achieve 98.83% on the MSTAR database and 92.67% on the Terra<span class="hlt">SAR</span>-X ship database.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20658019','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20658019"><span id="translatedtitle">Calculation of single-beam two-photon <span class="hlt">absorption</span> <span class="hlt">rate</span> of lanthanides: Effective operator method and perturbative expansion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Duan, C.-K.; Ruan Gang; Reid, Michael F.</p> <p>2004-11-01</p> <p>Perturbative contributions to single-beam two-photon transition <span class="hlt">rates</span> may be divided into two types. The first, involving low-energy intermediate states, require a high-order perturbation treatment, or an exact diagonalization. The other, involving high-energy intermediate states, only require a low-order perturbation treatment. We show how to partition the effective transition operator into two terms, corresponding to these two types, in such a way that a many-body perturbation expansion may be generated that obeys the linked cluster theorem and has a simple diagrammatic representation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060051638&hterms=sars&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsars','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060051638&hterms=sars&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsars"><span id="translatedtitle">On Ambiguities in <span class="hlt">SAR</span> Design</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, Anthony</p> <p>2006-01-01</p> <p>Ambiguities are an aliasing effect caused by the periodic sampling of the scene backscatter inherent to pulsed radar systems such as Synthetic Aperture radar (<span class="hlt">SAR</span>). In this paper we take a fresh look at the relationship between <span class="hlt">SAR</span> range and azimuth ambiguity constraints on the allowable pulse repetition frequency (PRF) and the antenna length. We show that for high squint angles smaller antennas may be feasible in some cases. For some applications, the ability to form a synthetic aperture at high squint angles is desirable, but the size of the antenna causes problems in the design of systems capable of such operation. This is because the <span class="hlt">SAR</span> system design is optimized for a side-looking geometry. In two examples design examples we take a suboptimum antenna size and examine the performance in terms of azimuth resolution and swath width as a function of squint angle. We show that for stripmap <span class="hlt">SARs</span>, the swath width is usually worse for off-boresight squint angles, because it is severely limited by range walk, except in cases where we relax the spatial resolution. We consider the implications for the design of modest-resolution, narrow swath, scanning <span class="hlt">SAR</span> scatterometers .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27228950','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27228950"><span id="translatedtitle">A method for assessing real time <span class="hlt">rates</span> of dissolution and <span class="hlt">absorption</span> of carbohydrate and other food matrices in human subjects.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lentle, R G; Sequeira, I R; Hardacre, A K; Reynolds, G</p> <p>2016-06-15</p> <p>We prepared pasta of differing physical dimensions but identical chemical composition that contained two monosaccharide probes (lactulose and mannitol) that are absorbed passively and promptly excreted in urine. We showed that the <span class="hlt">rates</span> of their liberation from the pasta under simulated gastric and small intestinal conditions largely depended upon the <span class="hlt">rate</span> of digestion of the starchy matrix. We showed, in 20 female subjects, that excretion of mannitol was slower from the pasta with the larger particle size. Hence, after consumption of either the powdered pasta or the simple solution of probe sugars, the mass of mannitol excreted between 1 and 2½ hours was greater than that excreted between 2½ and 4 hours. However these masses did not differ significantly after consumption of the pasta pellets. These differences were not reflected in the concurrent patterns of variation in either serum glucose or insulin taken over 120 minutes, their levels being similar for pasta pellets and powder with their peak values occurring synchronously during the first hour. Hence feeding test foods impregnated with lactulose and mannitol probes provided a reproducible and practical means of assessing the timing of digestion of the carbohydrate matrix and showed that this was more protracted than suggested by post prandial glucose levels. Further, the transit times calculated on a basis of the ratios of the two marker sugars could identify that the prolongation of digestion of larger particles was not accompanied by retention of digesta in particular segments of the gut. PMID:27228950</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cdc.gov/sars/about/fs-closecontact.html','NIH-MEDLINEPLUS'); return false;" href="http://www.cdc.gov/sars/about/fs-closecontact.html"><span id="translatedtitle"><span class="hlt">SARS</span> Patients and Their Close Contacts</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Fact Sheet for <span class="hlt">SARS</span> Patients and Their Close Contacts Format: Select one PDF [256 KB] Recommend on ... that are not now known. What does "close contact" mean? In the context of <span class="hlt">SARS</span>, close contact ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20130010590&hterms=beam&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dbeam','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20130010590&hterms=beam&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dbeam"><span id="translatedtitle">Sweep<span class="hlt">SAR</span>: Beam-forming on Receive Using a Reflector-Phased Array Feed Combination for Spaceborne <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, A.; Krieger, G.; Rosen, P.; Younis, M.; Johnson, W. T. K.; Huber, S.; Jordan, R.; Moreira, A.</p> <p>2012-01-01</p> <p>In this paper, an alternative approach is described that is suited for longer wavelength <span class="hlt">SARs</span> in particular, employing a large, deployable reflector antenna and a much simpler phased array feed. To illuminate a wide swath, a substantial fraction of the phased array feed is excited on transmit to sub-illuminate the reflector. Shorter transmit pulses are required than for conventional <span class="hlt">SAR</span>. On receive, a much smaller portion of the phased array feed is used to collect the return echo, so that a greater portion of the reflector antenna area is used. The locus of the portion of the phased array used on receive is adjusted using an analog beam steering network, to 'sweep' the receive beam(s) across the illuminated swath, tracking the return echo. This is similar in some respects to the whiskbroom approach to optical sensors, hence the name: Sweep<span class="hlt">SAR.SweepSAR</span> has advantages over conventional <span class="hlt">SAR</span> in that it requires less transmit power, and if the receive beam is narrow enough, it is relatively immune to range ambiguities. Compared to direct radiating arrays with digital beam- forming, it is much simpler to implement, uses currently available technologies, is better suited for longer wavelength systems, and does not require extremely high data <span class="hlt">rates</span> or onboard processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27380878','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27380878"><span id="translatedtitle">Improved Shock Tube Measurement of the CH4 + Ar = CH3 + H + Ar <span class="hlt">Rate</span> Constant using UV Cavity-Enhanced <span class="hlt">Absorption</span> Spectroscopy of CH3.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Shengkai; Davidson, David F; Hanson, Ronald K</p> <p>2016-07-21</p> <p>We report an improved measurement for the <span class="hlt">rate</span> constant of methane dissociation in argon (CH4 + Ar = CH3 + H + Ar) behind reflected shock waves. The experiment was conducted using a sub-parts per million sensitivity CH3 diagnostic recently developed in our laboratory based on ultraviolet cavity-enhanced <span class="hlt">absorption</span> spectroscopy. The high sensitivity of this diagnostic allowed for measurements of quantitatively resolved CH3 time histories during the initial stage of CH4 pyrolysis, where the reaction system is clean and free from influences of secondary reactions and temperature change. This high sensitivity also allowed extension of our measurement range to much lower temperatures (<1500 K). The current-reflected shock measurements were performed at temperatures between 1487 and 1866 K and pressures near 1.7 atm, resulting in the following Arrhenius <span class="hlt">rate</span> constant expression for the title reaction: k(1.7 atm) = 3.7 × 10(16) exp(-42 200 K/T) cm(3)/mol·s, with a 2σ uncertainty factor of 1.25. The current data are in good consensus with various theoretical and review studies, but at the low temperature end they suggest a slightly higher (up to 35%) <span class="hlt">rate</span> constant compared to these previous results. A re-evaluation of previous and current experimental data in the falloff region was also performed, yielding updated expressions for both the low-pressure limit and the high-pressure limit <span class="hlt">rate</span> constants and improved agreement with all existing data. PMID:27380878</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1174455','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1174455"><span id="translatedtitle">Method for removing RFI from <span class="hlt">SAR</span> images</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Doerry, Armin W.</p> <p>2003-08-19</p> <p>A method of removing RFI from a <span class="hlt">SAR</span> by comparing two <span class="hlt">SAR</span> images on a pixel by pixel basis and selecting the pixel with the lower magnitude to form a composite image. One <span class="hlt">SAR</span> image is the conventional image produced by the <span class="hlt">SAR</span>. The other image is created from phase-history data which has been filtered to have the frequency bands containing the RFI removed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930063989&hterms=1581&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231581','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930063989&hterms=1581&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231581"><span id="translatedtitle">Registration of interferometric <span class="hlt">SAR</span> images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, Qian; Vesecky, John F.; Zebker, Howard A.</p> <p>1992-01-01</p> <p>Interferometric synthetic aperture radar (INSAR) is a new way of performing topography mapping. Among the factors critical to mapping accuracy is the registration of the complex <span class="hlt">SAR</span> images from repeated orbits. A new algorithm for registering interferometric <span class="hlt">SAR</span> images is presented. A new figure of merit, the average fluctuation function of the phase difference image, is proposed to evaluate the fringe pattern quality. The process of adjusting the registration parameters according to the fringe pattern quality is optimized through a downhill simplex minimization algorithm. The results of applying the proposed algorithm to register two pairs of Seasat <span class="hlt">SAR</span> images with a short baseline (75 m) and a long baseline (500 m) are shown. It is found that the average fluctuation function is a very stable measure of fringe pattern quality allowing very accurate registration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930063572&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930063572&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut"><span id="translatedtitle">Monsoon '90 - Preliminary <span class="hlt">SAR</span> results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dubois, Pascale C.; Van Zyl, Jakob J.; Guerra, Abel G.</p> <p>1992-01-01</p> <p>Multifrequency polarimetric synthetic aperture radar (<span class="hlt">SAR</span>) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two <span class="hlt">SAR</span> data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric <span class="hlt">SAR</span> data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920018779&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920018779&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut"><span id="translatedtitle">Monsoon 1990: Preliminary <span class="hlt">SAR</span> results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vanzyl, Jakob J.; Dubois, Pascale; Guerra, Abel</p> <p>1991-01-01</p> <p>Multifrequency polarimetric synthetic aperture radar (<span class="hlt">SAR</span>) images of the Walnut Gulch watershed near Tombstone, Arizona were acquired on 28 Mar. 1990 and on 1 Aug. 1990. Trihedral corner reflectors were deployed prior to both overflights to allow calibration of the two <span class="hlt">SAR</span> data sets. During both overflights, gravimetric soil moisture and dielectric constant measurements were made. Detailed vegetation height, density, and water content measurements were made as part of the Monsoon 1990 Experiment. Preliminary results based on analysis of the multitemporal polarimetric <span class="hlt">SAR</span> data are presented. Only the C-band data (5.7-cm wavelength) radar images show significant difference between Mar. and Aug., with the strongest difference observed in the HV images. Based on the radar data analysis and the in situ measurements, we conclude that these differences are mainly due to changes in the vegetation and not due to the soil moisture changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26377774','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26377774"><span id="translatedtitle">Measuring the <span class="hlt">Absorption</span> <span class="hlt">Rate</span> of CO2 in Nonaqueous CO2-Binding Organic Liquid Solvents with a Wetted-Wall Apparatus.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mathias, Paul M; Zheng, Feng; Heldebrant, David J; Zwoster, Andy; Whyatt, Greg; Freeman, Charles M; Bearden, Mark D; Koech, Phillip</p> <p>2015-11-01</p> <p>The kinetics of the <span class="hlt">absorption</span> of CO2 into two nonaqueous CO2-binding organic liquid (CO2 BOL) solvents were measured at T=35, 45, and 55 °C with a wetted-wall column. Selected CO2 loadings were run with a so-called "first-generation" CO2 BOL, comprising an independent base and alcohol, and a "second-generation" CO2 BOL, in which the base and alcohol were conjoined. Liquid-film mass-transfer coefficient (k'g ) values for both solvents were measured to be comparable to values for monoethanolamine and piperazine aqueous solvents under a comparable driving force, in spite of far higher solution viscosities. An inverse temperature dependence of the k'g value was also observed, which suggests that the physical solubility of CO2 in organic liquids may be making CO2 mass transfer faster than expected. Aspen Plus software was used to model the kinetic data and compare the CO2 <span class="hlt">absorption</span> behavior of nonaqueous solvents with that of aqueous solvent platforms. This work continues our development of the CO2 BOL solvents. Previous work established the thermodynamic properties related to CO2 capture. The present paper quantitatively studies the kinetics of CO2 capture and develops a <span class="hlt">rate</span>-based model. PMID:26377774</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930000112&hterms=registration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dregistration','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930000112&hterms=registration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dregistration"><span id="translatedtitle">Registration Of <span class="hlt">SAR</span> Images With Multisensor Images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Evans, Diane L.; Burnette, Charles F.; Van Zyl, Jakob J.</p> <p>1993-01-01</p> <p>Semiautomated technique intended primarily to facilitate registration of polarimetric synthetic-aperture-radar (<span class="hlt">SAR</span>) images with other images of same or partly overlapping terrain while preserving polarization information conveyed by <span class="hlt">SAR</span> data. Technique generally applicable in sense one or both of images to be registered with each other generated by polarimetric or nonpolarimetric <span class="hlt">SAR</span>, infrared radiometry, conventional photography, or any other applicable sensing method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920018771&hterms=Ecosystems+classification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEcosystems%2Bclassification','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920018771&hterms=Ecosystems+classification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEcosystems%2Bclassification"><span id="translatedtitle">Progress towards <span class="hlt">SAR</span> based ecosystem analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ranson, K. Jon; Sun, Guoqing</p> <p>1991-01-01</p> <p>Recent progress towards a synthetic aperture radar (<span class="hlt">SAR</span>) based system for determining forest ecosystem attributes is discussed. Our <span class="hlt">SAR</span> data processing and analysis sequence, from calibration through classification, is described. In addition, the usefulness of <span class="hlt">SAR</span> image data for identifying ecosystem classes is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8008E..1OG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8008E..1OG"><span id="translatedtitle"><span class="hlt">SAR</span> and In<span class="hlt">SAR</span> georeferencing algorithms for inertial navigation systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Greco, M.; Kulpa, K.; Pinelli, G.; Samczynski, P.</p> <p>2011-10-01</p> <p>This paper presents the concept of Synthetic Aperture Radar (<span class="hlt">SAR</span>) and Interferemetric <span class="hlt">SAR</span> (In<span class="hlt">SAR</span>) georeferencing algorithms dedicated for <span class="hlt">SAR</span> based augmented Inertial Navigation Architecture (SARINA). The SARINA is a novel concept of the Inertial Navigation System (INS), which utilized the <span class="hlt">SAR</span> radar as an additional sensor to provide information about the platform trajectory position and compensate an aircraft drift due to Inertial Measurement Unit (IMU) errors, Global Positioning System (GPS) lack of integrity, etc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3960095','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3960095"><span id="translatedtitle">How Change of Public Transportation Usage Reveals Fear of the <span class="hlt">SARS</span> Virus in a City</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Kuo-Ying</p> <p>2014-01-01</p> <p>The outbreaks of the severe acute respiratory syndrome (<span class="hlt">SARS</span>) epidemic in 2003 resulted in unprecedented impacts on people's daily life. One of the most significant impacts to people is the fear of contacting the <span class="hlt">SARS</span> virus while engaging daily routine activity. Here we use data from daily underground ridership in Taipei City and daily reported new <span class="hlt">SARS</span> cases in Taiwan to model the dynamics of the public fear of the <span class="hlt">SARS</span> virus during the wax and wane of the <span class="hlt">SARS</span> period. We found that for each reported new <span class="hlt">SARS</span> case there is an immediate loss of about 1200 underground ridership (the fresh fear). These daily loss <span class="hlt">rates</span> dissipate to the following days with an e-folding time of about 28 days, reflecting the public perception on the risk of contacting <span class="hlt">SARS</span> virus when traveling with the underground system (the residual fear). About 50% of daily ridership was lost during the peak of the 2003 <span class="hlt">SARS</span> period, compared with the loss of 80% daily ridership during the closure of the underground system after Typhoon Nari, the loss of 50–70% ridership due to the closure of the governmental offices and schools during typhoon periods, and the loss of 60% daily ridership during Chinese New Year holidays. PMID:24647278</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984DorPo...4...29S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984DorPo...4...29S"><span id="translatedtitle">Realtime processor of <span class="hlt">SAR</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schotter, R.</p> <p></p> <p>Attention is given to potential applications of a synthetic aperture radar (<span class="hlt">SAR</span>) real time processor which was developed for Space Shuttle-based earth sensing, and which may prove useful in military surveillance, ocean wave studies, ship movements in territorial waters, land conservation, geology, and mineralogical prospecting. The <span class="hlt">SAR</span> processor's signal processing task is characterized by complex algorithms and large quantities of raw data/time unit. A 'pipeline' configuration has been judged optimal for this type of processing, and it will consist of digital hardware modules for Fourier transform, digital filtering, two-dimensional image memory, and complex multiplication.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910031189&hterms=decibel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddecibel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910031189&hterms=decibel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddecibel"><span id="translatedtitle">Squint mode <span class="hlt">SAR</span> processing algorithms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, C. Y.; Jin, M.; Curlander, J. C.</p> <p>1989-01-01</p> <p>The unique characteristics of a spaceborne <span class="hlt">SAR</span> (synthetic aperture radar) operating in a squint mode include large range walk and large variation in the Doppler centroid as a function of range. A pointing control technique to reduce the Doppler drift and a new processing algorithm to accommodate large range walk are presented. Simulations of the new algorithm for squint angles up to 20 deg and look angles up to 44 deg for the Earth Observing System (Eos) L-band <span class="hlt">SAR</span> configuration demonstrate that it is capable of maintaining the resolution broadening within 20 percent and the ISLR within a fraction of a decibel of the theoretical value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910000148&hterms=types+polarization&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtypes%2Bpolarization','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910000148&hterms=types+polarization&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtypes%2Bpolarization"><span id="translatedtitle">Polarization Filtering of <span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dubois, Pascale C.; Van Zyl, Jakob J.</p> <p>1991-01-01</p> <p>Theoretical analysis of polarization filtering of synthetic-aperture-radar (<span class="hlt">SAR</span>) returns provide hybrid method applied to either (1) maximize signal-to-noise ratio of return from given target or (2) enhance contrast between targets of two different types (that have different polarization properties). Method valid for both point and extended targets and for both monostatic and bistatic radars as well as <span class="hlt">SAR</span>. Polarization information in return signals provides more complete description of radar-scattering properties of targets and used to obtain additional information about targets for use in classifying them, discriminating between them, or enhancing features of radar images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.9077E..0QK&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.9077E..0QK&link_type=ABSTRACT"><span id="translatedtitle">Indoor experimental facility for airborne synthetic aperture radar (<span class="hlt">SAR</span>) configurations - rail-<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirose, Getachew; Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Koenig, Francois; Narayanan, Ram M.</p> <p>2014-05-01</p> <p>The Army Research Laboratory (ARL) is developing an indoor experimental facility to evaluate and assess airborne synthetic-aperture-radar-(<span class="hlt">SAR</span>)-based detection capabilities. The rail-<span class="hlt">SAR</span> is located in a multi-use facility that also provides a base for research and development in the area of autonomous robotic navigation. Radar explosive hazard detection is one key sensordevelopment area to be investigated at this indoor facility. In particular, the mostly wooden, multi-story building houses a two (2) story housing structure and an open area built over a large sandbox. The housing structure includes reconfigurable indoor walls which enable the realization of multiple See-Through-The-Wall (STTW) scenarios. The open sandbox, on the other hand, allows for surface and buried explosive hazard scenarios. The indoor facility is not <span class="hlt">rated</span> for true explosive hazard materials so all targets will need to be inert and contain surrogate explosive fills. In this paper we discuss the current system status and describe data collection exercises conducted using canonical targets and frequencies that may be of interest to designers of ultra-wideband (UWB) airborne, ground penetrating <span class="hlt">SAR</span> systems. A bi-static antenna configuration will be used to investigate the effects of varying airborne <span class="hlt">SAR</span> parameters such as depression angle, bandwidth, and integration angle, for various target types and deployment scenarios. Canonical targets data were used to evaluate overall facility capabilities and limitations. These data is analyzed and summarized for future evaluations. Finally, processing techniques for dealing with RF multi-path and RFI due to operating inside the indoor facility are described in detail. Discussion of this facility and its capabilities and limitations will provide the explosive hazard community with a great airborne platform asset for sensor to target assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8746E..0AD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8746E..0AD"><span id="translatedtitle"><span class="hlt">SAR</span> digital spotlight implementation in MATLAB</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dungan, Kerry E.; Gorham, LeRoy A.; Moore, Linda J.</p> <p>2013-05-01</p> <p>Legacy synthetic aperture radar (<span class="hlt">SAR</span>) exploitation algorithms were image-based algorithms, designed to exploit complex and/or detected <span class="hlt">SAR</span> imagery. In order to improve the efficiency of the algorithms, image chips, or region of interest (ROI) chips, containing candidate targets were extracted. These image chips were then used directly by exploitation algorithms for the purposes of target discrimination or identification. Recent exploitation research has suggested that performance can be improved by processing the underlying phase history data instead of standard <span class="hlt">SAR</span> imagery. Digital Spotlighting takes the phase history data of a large image and extracts the phase history data corresponding to a smaller spatial subset of the image. In a typical scenario, this spotlighted phase history data will contain much fewer samples than the original data but will still result in an alias-free image of the ROI. The Digital Spotlight algorithm can be considered the first stage in a "two-stage backprojection" image formation process. As the first stage in two-stage backprojection, Digital Spotlighting filters the original phase history data into a number of "pseudo"-phase histories that segment the scene into patches, each of which contain a reduced number of samples compared to the original data. The second stage of the imaging process consists of standard backprojection. The data <span class="hlt">rate</span> reduction offered by Digital Spotlighting improves the computational efficiency of the overall imaging process by significantly reducing the total number of backprojection operations. This paper describes the Digital Spotlight algorithm in detail and provides an implementation in MATLAB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7337E..0MH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7337E..0MH"><span id="translatedtitle">Utilizing feedback in adaptive <span class="hlt">SAR</span> ATR systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Horsfield, Owen; Blacknell, David</p> <p>2009-05-01</p> <p>Existing <span class="hlt">SAR</span> ATR systems are usually trained off-line with samples of target imagery or CAD models, prior to conducting a mission. If the training data is not representative of mission conditions, then poor performance may result. In addition, it is difficult to acquire suitable training data for the many target types of interest. The Adaptive <span class="hlt">SAR</span> ATR Problem Set (AdaptSAPS) program provides a MATLAB framework and image database for developing systems that adapt to mission conditions, meaning less reliance on accurate training data. A key function of an adaptive system is the ability to utilise truth feedback to improve performance, and it is this feature which AdaptSAPS is intended to exploit. This paper presents a new method for <span class="hlt">SAR</span> ATR that does not use training data, based on supervised learning. This is achieved by using feature-based classification, and several new shadow features have been developed for this purpose. These features allow discrimination of vehicles from clutter, and classification of vehicles into two classes: targets, comprising military combat types, and non-targets, comprising bulldozers and trucks. The performance of the system is assessed using three baseline missions provided with AdaptSAPS, as well as three additional missions. All performance metrics indicate a distinct learning trend over the course of a mission, with most third and fourth quartile performance levels exceeding 85% correct classification. It has been demonstrated that these performance levels can be maintained even when truth feedback <span class="hlt">rates</span> are reduced by up to 55% over the course of a mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22356763','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22356763"><span id="translatedtitle">The COS/UVES <span class="hlt">absorption</span> survey of the Magellanic stream. III. Ionization, total mass, and inflow <span class="hlt">rate</span> onto the Milky Way</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fox, Andrew J.; Thom, Christopher; Tumlinson, Jason; Ely, Justin; Kumari, Nimisha; Wakker, Bart P.; Hernandez, Audra K.; Haffner, L. Matthew; Barger, Kathleen A.; Lehner, Nicolas; Howk, J. Christopher; Richter, Philipp; Charlton, Jane C.; Westmeier, Tobias; Misawa, Toru; Rodriguez-Hidalgo, Paola</p> <p>2014-06-01</p> <p>Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in <span class="hlt">absorption</span>, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30° of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV <span class="hlt">absorption</span> at Magellanic velocities, indicating that the total cross-section of the Magellanic System is ≈11,000 deg{sup 2}, or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be ≈2.0 × 10{sup 9} M {sub ☉} (d/55 kpc){sup 2}, with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of ∼0.5-1.0 Gyr, it will represent an average inflow <span class="hlt">rate</span> of ∼3.7-6.7 M {sub ☉} yr{sup –1}, potentially raising the Galactic star formation <span class="hlt">rate</span>. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27447635','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27447635"><span id="translatedtitle">Robust Ground Target Detection by <span class="hlt">SAR</span> and IR Sensor Fusion Using Adaboost-Based Feature Selection.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Sungho; Song, Woo-Jin; Kim, So-Hyun</p> <p>2016-01-01</p> <p>Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (<span class="hlt">SAR</span>) images or infrared (IR) images. <span class="hlt">SAR</span>-based detectors can provide a high detection <span class="hlt">rate</span> with a high false alarm <span class="hlt">rate</span> to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level <span class="hlt">SAR</span> and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection <span class="hlt">rate</span> and low false alarm <span class="hlt">rate</span>. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a <span class="hlt">SAR</span> and IR target detection method using modified Boolean map visual theory (modBMVT) and feature-selection based fusion. Previous methods applied different algorithms to detect <span class="hlt">SAR</span> and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in <span class="hlt">SAR</span> target detection. This study examined the image characteristics and proposed a unified <span class="hlt">SAR</span> and IR target detection method by inserting a median local average filter (MLAF, pre-filter) and an asymmetric morphological closing filter (AMCF, post-filter) into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous <span class="hlt">SAR</span> and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC)-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good <span class="hlt">SAR</span> and IR target detection performance through feature selection-based decision fusion on a synthetic database generated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4970160','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4970160"><span id="translatedtitle">Robust Ground Target Detection by <span class="hlt">SAR</span> and IR Sensor Fusion Using Adaboost-Based Feature Selection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kim, Sungho; Song, Woo-Jin; Kim, So-Hyun</p> <p>2016-01-01</p> <p>Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (<span class="hlt">SAR</span>) images or infrared (IR) images. <span class="hlt">SAR</span>-based detectors can provide a high detection <span class="hlt">rate</span> with a high false alarm <span class="hlt">rate</span> to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level <span class="hlt">SAR</span> and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection <span class="hlt">rate</span> and low false alarm <span class="hlt">rate</span>. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a <span class="hlt">SAR</span> and IR target detection method using modified Boolean map visual theory (modBMVT) and feature-selection based fusion. Previous methods applied different algorithms to detect <span class="hlt">SAR</span> and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in <span class="hlt">SAR</span> target detection. This study examined the image characteristics and proposed a unified <span class="hlt">SAR</span> and IR target detection method by inserting a median local average filter (MLAF, pre-filter) and an asymmetric morphological closing filter (AMCF, post-filter) into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous <span class="hlt">SAR</span> and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC)-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good <span class="hlt">SAR</span> and IR target detection performance through feature selection-based decision fusion on a synthetic database generated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27240143','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27240143"><span id="translatedtitle">Experimental and numerical analysis of B1(+) field and <span class="hlt">SAR</span> with a new transmit array design for 7T breast MRI.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Junghwan; Krishnamurthy, Narayan; Santini, Tales; Zhao, Yujuan; Zhao, Tiejun; Bae, Kyongtae Ty; Ibrahim, Tamer S</p> <p>2016-08-01</p> <p>Developing a radiofrequency (RF) coil system that produces a uniform B1(+) field (circularly polarized component of the transverse magnetic field responsible for excitation) and low specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) is critical for high performance ultrahigh field human imaging. In this study, we provide the design of a new eight channel radiofrequency (RF) transmit (Tx) array for breast MRI at 7T. A numerical analysis utilizing an in-house finite difference time domain (FDTD) package was carried out in (1) four breast models, (2) homogeneous spherical model and (3) full body model to calculate the B1(+) intensity (μT) and homogeneity represented by coefficient of variation (CoV=standard deviation/mean) in the proposed RF array design. The numerical results were compared with that measured in breast phantom (Bphantom) and homogeneous spherical phantom at 7T MRI and showed very good agreement. Average and peak <span class="hlt">SARs</span> were also calculated in the four breast models and the temperature rises due to the operation of the RF array were also measured in the Bphantom. The proposed RF array; which can operate in a single or multi transmit modes, demonstrates homogeneous RF field excitation with acceptable local/average <span class="hlt">SAR</span> levels for breast MRI at 7T. PMID:27240143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JMagR.269...55K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JMagR.269...55K&link_type=ABSTRACT"><span id="translatedtitle">Experimental and numerical analysis of B1+ field and <span class="hlt">SAR</span> with a new transmit array design for 7 T breast MRI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Junghwan; Krishnamurthy, Narayan; Santini, Tales; Zhao, Yujuan; Zhao, Tiejun; Bae, Kyongtae Ty; Ibrahim, Tamer S.</p> <p>2016-08-01</p> <p>Developing a radiofrequency (RF) coil system that produces a uniform B1+ field (circularly polarized component of the transverse magnetic field responsible for excitation) and low specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) is critical for high performance ultrahigh field human imaging. In this study, we provide the design of a new eight channel radiofrequency (RF) transmit (Tx) array for breast MRI at 7 T. A numerical analysis utilizing an in-house finite difference time domain (FDTD) package was carried out in (1) four breast models, (2) homogeneous spherical model and (3) full body model to calculate the B1+ intensity (μT) and homogeneity represented by coefficient of variation (CoV = standard deviation/mean) in the proposed RF array design. The numerical results were compared with that measured in breast phantom (Bphantom) and homogeneous spherical phantom at 7 T MRI and showed very good agreement. Average and peak <span class="hlt">SARs</span> were also calculated in the four breast models and the temperature rises due to the operation of the RF array were also measured in the Bphantom. The proposed RF array; which can operate in a single or multi transmit modes, demonstrates homogeneous RF field excitation with acceptable local/average <span class="hlt">SAR</span> levels for breast MRI at 7 T.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830005505','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830005505"><span id="translatedtitle">Further SEASAT <span class="hlt">SAR</span> coastal ocean wave analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kasischke, E. S.; Shuchman, R. A.; Meadows, G. A.; Jackson, P. L.; Tseng, Y.</p> <p>1981-01-01</p> <p>Analysis techniques used to exploit SEASAT synthetic aperture radar (<span class="hlt">SAR</span>) data of gravity waves are discussed and the SEASAT <span class="hlt">SAR</span>'s ability to monitor large scale variations in gravity wave fields in both deep and shallow water is evaluated. The <span class="hlt">SAR</span> analysis techniques investigated included motion compensation adjustments and the semicausal model for spectral analysis of <span class="hlt">SAR</span> wave data. It was determined that spectra generated from fast Fourier transform analysis (FFT) of <span class="hlt">SAR</span> wave data were not significantly altered when either range telerotation adjustments or azimuth focus shifts were used during processing of the <span class="hlt">SAR</span> signal histories, indicating that SEASAT imagery of gravity waves is not significantly improved or degraded by motion compensation adjustments. Evaluation of the semicausal (SC) model using SEASAT <span class="hlt">SAR</span> data from Rev. 974 indicates that the SC spectral estimates were not significantly better than the FFT results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6017611','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6017611"><span id="translatedtitle">Frequency-dependent energy <span class="hlt">absorption</span> in the body and tail of the rodent carcass exposed to radiofrequency radiation. Final report, 31 June-31 December 1985</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bixby, R.R.; Padilla, J.M.</p> <p>1987-04-01</p> <p>The proportion of energy absorbed by the tail of a rat carcass was determined. Male (288 g - 457 g) and female (195 g - 249 g) Sprague-Dawley rat carcasses were exposed to far-field, continuous-wave radiofrequency radiation (RFR). The carcasses were split into two mixed groups: one group was exposed to 700-MHz RFR; and the other, to 350-MHz RFR. Immediately after each exposure, the tail was severed, and the specific <span class="hlt">absorption</span> <span class="hlt">rates</span> (<span class="hlt">SAR</span>) of the tail and body were determined by Dewar flask calorimetry. For example, a 195 g female exposed to 700 MHz yielded <span class="hlt">SARs</span> of 1.26 and 3.64 mW/g (normalized to 1 nW/cm2 incident power density) for its body and tail, respectively; the tail contributed 6.7% to the total energy <span class="hlt">absorption</span>. For a 205 g female exposed to 350 MHz, however, the tail contributed 19.0% to the whole-body <span class="hlt">absorption</span>. Normalized <span class="hlt">SARs</span> of 0.40 and 4.03 nW/g per mW/cm2 were obtained for the body and tail, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12811416','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12811416"><span id="translatedtitle">[Severe acute respiratory syndrome (<span class="hlt">SARS</span>)].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gillissen, Adrian; Ruf, Bernhard R</p> <p>2003-06-15</p> <p>Severe acute respiratory syndrome (<span class="hlt">SARS</span>) is a viral disease, observed primarily in Southern China in November 2002, with variable flu-like symptoms and pneumonia, in approx. 5% leading to death from respiratory distress syndrome (RDS). The disease was spread over more than 30 states all over the globe by <span class="hlt">SARS</span>-virus-infected travelers. WHO and CDC received first information about a new syndrome by the end of February 2003, after the first cases outside the Republic of China had been observed. A case in Hanoi, Vietnam, led to the first precise information about the new disease entity to WHO, by Dr. Carlo Urbani, a co-worker of WHO/Doctors without Borders, who had been called by local colleagues to assist in the management of a patient with an unknown severe disease by the end of February 2003. Dr. Urbani died from <span class="hlt">SARS</span>, as did many other health care workers. In the meantime, more than 7,000 cases have been observed worldwide, predominantly in China and Hong Kong, but also in Taiwan, Canada, Singapore, and the USA, and many other countries, and more than 600 of these patients died from RDS. Since the beginning of March 2003, when WHO and CDC started their activities, in close collaboration with a group of international experts, including the Bernhard-Nocht-Institute in Hamburg and the Department of Virology in Frankfurt/Main, a previously impossible success in the disclosure of the disease was achieved. Within only 8 weeks of research it was possible to describe the infectious agent, a genetically modified coronavirus, including the genetic sequence, to establish specific diagnostic PCR methods and to find possible mechanisms for promising therapeutic approaches. In addition, intensifying classical quarantine and hospital hygiene measures, it was possible to limit <span class="hlt">SARS</span> in many countries to sporadic cases, and to reduce the disease in countries such as Canada and Vietnam. This review article summarizes important information about many issues of <span class="hlt">SARS</span> (May 15th, 2003</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A11A0004O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A11A0004O"><span id="translatedtitle">Photochemical parameters of atmospheric source gases: accurate determination of OH reaction <span class="hlt">rate</span> constants over atmospheric temperatures, UV and IR <span class="hlt">absorption</span> spectra</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Orkin, V. L.; Khamaganov, V. G.; Martynova, L. E.; Kurylo, M. J.</p> <p>2012-12-01</p> <p> instrumental uncertainties related to our FP-RF experiment proves a total uncertainty of the OH reaction <span class="hlt">rate</span> constant to be as small as ca. 2-3%. The high precision of kinetic measurements allows reliable determination of weak temperature dependences of the <span class="hlt">rate</span> constants and clear resolution of the curvature of the Arrhenius plots for the OH reaction <span class="hlt">rate</span> constants of various compounds. The results of OH reaction <span class="hlt">rate</span> constant determinations between 220 K and 370 K will be presented. Similarly, the accuracy of UV and IR <span class="hlt">absorption</span> measurements will be highlighted to provide an improved basis for atmospheric modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhDT........10W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhDT........10W"><span id="translatedtitle">Determination of mass loss and mass transfer <span class="hlt">rates</span> of Algol (Beta Persei) from the analysis of <span class="hlt">absorption</span> lines in the UV spectra obtained by the IUE satellite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wecht, Kristen</p> <p></p> <p>The International Ultraviolet Explorer (IUE) archive of high-resolution ultraviolet spectra of the eclipsing semi-detached binary star, Algol ([beta] Persei, HD 19356), taken from September 1978 to September 1989, is analyzed in order to characterize the movement of gas within and from this system. Light curves are constructed, using a total of 1647 continuum level measurements. These results support the semidetached status of this interacting binary star. Radial velocities, residual intensities, full width half maxima (FWHM), line asymmetries, and equivalent widths of UV <span class="hlt">absorption</span> lines for aluminum, magnesium, iron, and silicon in a range of ionization states are determined and analyzed. For selected epochs, we were able to isolate gas stream and photospheric contributions by an examination of the differences between spectral line shapes. We observed variations in line shape and strength, with orbital phase and epoch, indicating the presence of stable gas streams and circumstellar gas, and periods of increased mass-transfer activity associated with transient gas streams. The 1989 data indicates moderate activity. This epoch was examined most closely since it provides the greatest phase coverage. Spectral line profiles in 1978 and 1984 have the strongest gas-flow <span class="hlt">absorption</span> components, indicating that these are the epochs of the greatest activity. The dense phase coverage in September 1989 allows us to measure the mass loss <span class="hlt">rate</span> from Algol B into Algol A which is of order ~10 -14 [Special characters omitted.] /yr. Since the highest gas-flow velocities are in the 100 kilometer per second range, well below escape velocity, we conclude that systemic mass loss due to gas flow is small for the Algol system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18695413','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18695413"><span id="translatedtitle">Characterization of personal RF electromagnetic field exposure and actual <span class="hlt">absorption</span> for the general public.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Joseph, W; Vermeeren, G; Verloock, L; Heredia, Mauricio Masache; Martens, Luc</p> <p>2008-09-01</p> <p>In this paper, personal electromagnetic field exposure of the general public due to 12 different radiofrequency sources is characterized. Twenty-eight different realistic exposure scenarios based upon time, environment, activity, and location have been defined and a relevant number of measurements were performed with a personal exposure meter. Indoor exposure in office environments can be higher than outdoor exposure: 95th percentiles of field values due to WiFi ranged from 0.36 to 0.58 V m(-1), and for DECT values of 0.33 V m(-1) were measured. The downlink signals of GSM and DCS caused the highest outdoor exposures up to 0.52 V m(-1). The highest total field exposure occurred for mobile scenarios (inside a train or bus) from uplink signals of GSM and DCS (e.g., mobile phones) due to changing environmental conditions, handovers, and higher required transmitted signals from mobile phones due to penetration through windows while moving. A method to relate the exposure to the actual whole-body <span class="hlt">absorption</span> in the human body is proposed. An application is shown where the actual <span class="hlt">absorption</span> in a human body model due to a GSM downlink signal is determined. Fiftieth, 95th, and 99 th percentiles of the whole-body specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) due to this GSM signal of 0.58 microW kg(-1), 2.08 microW kg(-1), and 5.01 microW kg(-1) are obtained for a 95th percentile of 0.26 V m(-1). A practical usable function is proposed for the relation between the whole-body <span class="hlt">SAR</span> and the electric fields. The methodology of this paper enables epidemiological studies to make an analysis in combination with both electric field and actual whole-body <span class="hlt">SAR</span> values and to compare exposure with basic restrictions. PMID:18695413</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApJ...787..147F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApJ...787..147F"><span id="translatedtitle">The COS/UVES <span class="hlt">Absorption</span> Survey of the Magellanic Stream. III. Ionization, Total Mass, and Inflow <span class="hlt">Rate</span> onto the Milky Way</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fox, Andrew J.; Wakker, Bart P.; Barger, Kathleen A.; Hernandez, Audra K.; Richter, Philipp; Lehner, Nicolas; Bland-Hawthorn, Joss; Charlton, Jane C.; Westmeier, Tobias; Thom, Christopher; Tumlinson, Jason; Misawa, Toru; Howk, J. Christopher; Haffner, L. Matthew; Ely, Justin; Rodriguez-Hidalgo, Paola; Kumari, Nimisha</p> <p>2014-06-01</p> <p>Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in <span class="hlt">absorption</span>, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30° of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV <span class="hlt">absorption</span> at Magellanic velocities, indicating that the total cross-section of the Magellanic System is ≈11,000 deg2, or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be ≈2.0 × 109 M ⊙ (d/55 kpc)2, with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of ~0.5-1.0 Gyr, it will represent an average inflow <span class="hlt">rate</span> of ~3.7-6.7 M ⊙ yr-1, potentially raising the Galactic star formation <span class="hlt">rate</span>. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona. Based on observations taken under programs 11520, 11524, 11541, 11585, 11598, 11632, 11686, 11692, 12025, 12029, 12038, 12172, 12204, 12212, 12248, 12263, 12264, 12275, 12533, 12536, 12569, 12593, and 12604 of the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/953746','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/953746"><span id="translatedtitle">Controlling Data Collection to Support <span class="hlt">SAR</span> Image Rotation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Doerry, Armin W.; Cordaro, J. Thomas; Burns, Bryan L.</p> <p>2008-10-14</p> <p>A desired rotation of a synthetic aperture radar (<span class="hlt">SAR</span>) image can be facilitated by adjusting a <span class="hlt">SAR</span> data collection operation based on the desired rotation. The <span class="hlt">SAR</span> data collected by the adjusted <span class="hlt">SAR</span> data collection operation can be efficiently exploited to form therefrom a <span class="hlt">SAR</span> image having the desired rotational orientation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16022801','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16022801"><span id="translatedtitle">Asymptomatic <span class="hlt">SARS</span> coronavirus infection among healthcare workers, Singapore.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilder-Smith, Annelies; Teleman, Monica D; Heng, Bee H; Earnest, Arul; Ling, Ai E; Leo, Yee S</p> <p>2005-07-01</p> <p>We conducted a study among healthcare workers (HCWs) exposed to patients with severe acute respiratory syndrome (<span class="hlt">SARS</span>) before infection control measures were instituted. Of all exposed HCWs, 7.5% had asymptomatic <span class="hlt">SARS</span>-positive cases. Asymptomatic <span class="hlt">SARS</span> was associated with lower <span class="hlt">SARS</span> antibody titers and higher use of masks when compared to pneumonic <span class="hlt">SARS</span>. PMID:16022801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18503014','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18503014"><span id="translatedtitle">The <span class="hlt">SARS</span>-associated stigma of <span class="hlt">SARS</span> victims in the post-<span class="hlt">SARS</span> era of Hong Kong.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siu, Judy Yuen-man</p> <p>2008-06-01</p> <p>This article explores the disease-associated stigma attached to the <span class="hlt">SARS</span> victims in the post-<span class="hlt">SARS</span> era of Hong Kong. I argue that the <span class="hlt">SARS</span>-associated stigma did not decrease over time. Based on the ethnographic data obtained from 16 months of participant observation in a <span class="hlt">SARS</span> victims' self-help group and semistructured interviews, I argue that the <span class="hlt">SARS</span>-associated stigma was maintained, revived, and reconstructed by the biomedical encounters, government institutions, and public perception. I also provide new insight on how the <span class="hlt">SARS</span>-associated stigma could create problems for public health development in Hong Kong. As communicable diseases will be a continuing threat for the human society, understanding how the disease-associated stigma affects the outcomes of epidemic control measures will be crucial in developing a more responsive public health policy as well as medical follow-up and social support service to the diseased social groups of future epidemic outbreaks. PMID:18503014</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24553049','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24553049"><span id="translatedtitle">Prediction and comparison of downlink electric-field and uplink localised <span class="hlt">SAR</span> values for realistic indoor wireless planning.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Plets, David; Joseph, Wout; Aerts, Sam; Vanhecke, Kris; Vermeeren, Günter; Martens, Luc</p> <p>2014-12-01</p> <p>In this paper, for the first time a heuristic network calculator for both whole-body exposure due to indoor base station antennas or access points (downlink exposure) and localised exposure due to the mobile device (uplink exposure) in indoor wireless networks is presented. As an application, three phone call scenarios are investigated (Universal Mobile Telecommunications System (UMTS) macrocell, UMTS femtocell and WiFi voice-over-IP) and compared with respect to the electric-field strength and localised specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) distribution. Prediction models are created and successfully validated with an accuracy of 3 dB. The benefits of the UMTS power control mechanisms are demonstrated. However, dependent on the macrocell connection quality and on the user's average phone call connection time, also the macrocell solution might be preferential from an exposure point of view for the considered scenario. PMID:24553049</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26609371','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26609371"><span id="translatedtitle">Multi-coil approach to reduce electromagnetic energy <span class="hlt">absorption</span> for wirelessly powered implants.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>RamRakhyani, Anil Kumar; Lazzi, Gianluca</p> <p>2014-01-01</p> <p>Near-field inductive coupling is a commonly used technique for wireless power transfer (WPT) in biomedical implants. Owing to the close proximity of the implant coil(s) with the tissue ( ∼1 mm) and high current ( ∼100-300 mA) in the magnetic coil(s), a significant induced electric field can be generated for the operating frequency (1-20 MHz). In this Letter, a multi-coil-based WPT technique is proposed to selectively control the currents in the external and implant coils to reduce the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>). A three-coil WPT system, that can achieve 26% reduction in peak 1-g <span class="hlt">SAR</span> and 15% reduction in peak 10-g <span class="hlt">SAR</span>, as compared to a two-coil WPT system with the same dimensions, is implemented and used to demonstrate the effectiveness of the proposed approach. To achieve the seamless design for the external and implant electronics, the multi-coil system achieves the same voltage gain and bandwidth as the two-coil design with 46% improvement in the power transfer efficiency. PMID:26609371</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4613696','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4613696"><span id="translatedtitle">Multi-coil approach to reduce electromagnetic energy <span class="hlt">absorption</span> for wirelessly powered implants</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lazzi, Gianluca</p> <p>2014-01-01</p> <p>Near-field inductive coupling is a commonly used technique for wireless power transfer (WPT) in biomedical implants. Owing to the close proximity of the implant coil(s) with the tissue ( ∼1 mm) and high current ( ∼100–300 mA) in the magnetic coil(s), a significant induced electric field can be generated for the operating frequency (1–20 MHz). In this Letter, a multi-coil-based WPT technique is proposed to selectively control the currents in the external and implant coils to reduce the specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>). A three-coil WPT system, that can achieve 26% reduction in peak 1-g <span class="hlt">SAR</span> and 15% reduction in peak 10-g <span class="hlt">SAR</span>, as compared to a two-coil WPT system with the same dimensions, is implemented and used to demonstrate the effectiveness of the proposed approach. To achieve the seamless design for the external and implant electronics, the multi-coil system achieves the same voltage gain and bandwidth as the two-coil design with 46% improvement in the power transfer efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3675546','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3675546"><span id="translatedtitle">A <span class="hlt">SAR</span> Observation and Numerical Study on Ocean Surface Imprints of Atmospheric Vortex Streets</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Xiaofeng; Zheng, Weizhong; Zou, Cheng-Zhi; Pichel, William G.</p> <p>2008-01-01</p> <p>The sea surface imprints of Atmospheric Vortex Street (AVS) off Aleutian Volcanic Islands, Alaska were observed in two RADARSAT-1 Synthetic Aperture Radar (<span class="hlt">SAR</span>) images separated by about 11 hours. In both images, three pairs of distinctive vortices shedding in the lee side of two volcanic mountains can be clearly seen. The length and width of the vortex street are about 60-70 km and 20 km, respectively. Although the AVS's in the two <span class="hlt">SAR</span> images have similar shapes, the structure of vortices within the AVS is highly asymmetrical. The sea surface wind speed is estimated from the <span class="hlt">SAR</span> images with wind direction input from Navy NOGAPS model. In this paper we present a complete MM5 model simulation of the observed AVS. The surface wind simulated from the MM5 model is in good agreement with <span class="hlt">SAR</span>-derived wind. The vortex shedding <span class="hlt">rate</span> calculated from the model run is about 1 hour and 50 minutes. Other basic characteristics of the AVS including propagation speed of the vortex, Strouhal and Reynolds numbers favorable for AVS generation are also derived. The wind associated with AVS modifies the cloud structure in the marine atmospheric boundary layer. The AVS cloud pattern is also observed on a MODIS visible band image taken between the two RADARSAT <span class="hlt">SAR</span> images. An ENVISAT advance <span class="hlt">SAR</span> image taken 4 hours after the second RADARSAT <span class="hlt">SAR</span> image shows that the AVS has almost vanished.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26904039','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26904039"><span id="translatedtitle">Antigen Production in Plant to Tackle Infectious Diseases Flare Up: The Case of <span class="hlt">SARS</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Demurtas, Olivia C; Massa, Silvia; Illiano, Elena; De Martinis, Domenico; Chan, Paul K S; Di Bonito, Paola; Franconi, Rosella</p> <p>2016-01-01</p> <p>Severe acute respiratory syndrome (<span class="hlt">SARS</span>) is a dangerous infection with pandemic potential. It emerged in 2002 and its aetiological agent, the <span class="hlt">SARS</span> Coronavirus (<span class="hlt">SARS</span>-CoV), crossed the species barrier to infect humans, showing high morbidity and mortality <span class="hlt">rates</span>. No vaccines are currently licensed for <span class="hlt">SARS</span>-CoV and important efforts have been performed during the first outbreak to develop diagnostic tools. Here we demonstrate the transient expression in Nicotiana benthamiana of two important antigenic determinants of the <span class="hlt">SARS</span>-CoV, the nucleocapsid protein (N) and the membrane protein (M) using a virus-derived vector or agro-infiltration, respectively. For the M protein, this is the first description of production in plants, while for plant-derived N protein we demonstrate that it is recognized by sera of patients from the <span class="hlt">SARS</span> outbreak in Hong Kong in 2003. The availability of recombinant N and M proteins from plants opens the way to further evaluation of their potential utility for the development of diagnostic and protection/therapy tools to be quickly manufactured, at low cost and with minimal risk, to face potential new highly infectious <span class="hlt">SARS</span>-CoV outbreaks. PMID:26904039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4742786','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4742786"><span id="translatedtitle">Antigen Production in Plant to Tackle Infectious Diseases Flare Up: The Case of <span class="hlt">SARS</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Demurtas, Olivia C.; Massa, Silvia; Illiano, Elena; De Martinis, Domenico; Chan, Paul K. S.; Di Bonito, Paola; Franconi, Rosella</p> <p>2016-01-01</p> <p>Severe acute respiratory syndrome (<span class="hlt">SARS</span>) is a dangerous infection with pandemic potential. It emerged in 2002 and its aetiological agent, the <span class="hlt">SARS</span> Coronavirus (<span class="hlt">SARS</span>-CoV), crossed the species barrier to infect humans, showing high morbidity and mortality <span class="hlt">rates</span>. No vaccines are currently licensed for <span class="hlt">SARS</span>-CoV and important efforts have been performed during the first outbreak to develop diagnostic tools. Here we demonstrate the transient expression in Nicotiana benthamiana of two important antigenic determinants of the <span class="hlt">SARS</span>-CoV, the nucleocapsid protein (N) and the membrane protein (M) using a virus-derived vector or agro-infiltration, respectively. For the M protein, this is the first description of production in plants, while for plant-derived N protein we demonstrate that it is recognized by sera of patients from the <span class="hlt">SARS</span> outbreak in Hong Kong in 2003. The availability of recombinant N and M proteins from plants opens the way to further evaluation of their potential utility for the development of diagnostic and protection/therapy tools to be quickly manufactured, at low cost and with minimal risk, to face potential new highly infectious <span class="hlt">SARS</span>-CoV outbreaks. PMID:26904039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3356205','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3356205"><span id="translatedtitle">A facile inhibitor screening of <span class="hlt">SARS</span> coronavirus N protein using nanoparticle-based RNA oligonucleotide</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Roh, Changhyun</p> <p>2012-01-01</p> <p>Hundreds of million people worldwide have been infected with severe acute respiratory syndrome (<span class="hlt">SARS</span>), and the <span class="hlt">rate</span> of global death from <span class="hlt">SARS</span> has remarkably increased. Hence, the development of efficient drug treatments for the biological effects of <span class="hlt">SARS</span> is highly needed. We have previously shown that quantum dots (QDs)-conjugated RNA oligonucleotide is sensitive to the specific recognition of the <span class="hlt">SARS</span>-associated coronavirus (<span class="hlt">SARS</span>-CoV) nucleocapsid (N) protein. In this study, we found that a designed biochip could analyze inhibitors of the <span class="hlt">SARS</span>-CoV N protein using nanoparticle-based RNA oligonucleotide. Among the polyphenolic compounds examined, (−)-catechin gallate and (−)-gallocatechin gallate demonstrated a remarkable inhibition activity on <span class="hlt">SARS</span>-CoV N protein. (−)-catechin gallate and (−)-gallocatechin gallate attenuated the binding affinity in a concentrated manner as evidenced by QDs-conjugated RNA oligonucleotide on a designed biochip. At a concentration of 0.05 μg mL−1, (−)-catechin gallate and (−)-gallocatechin gallate showed more than 40% inhibition activity on a nanoparticle-based RNA oligonucleotide biochip system. PMID:22619553</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B7...23A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B7...23A&link_type=ABSTRACT"><span id="translatedtitle">Monitoring of Land Subsidence in Ravenna Municipality Using Integrated <span class="hlt">SAR</span> - GPS Techniques: Description and First Results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Artese, G.; Fiaschi, S.; Di Martire, D.; Tessitore, S.; Fabris, M.; Achilli, V.; Ahmed, A.; Borgstrom, S.; Calcaterra, D.; Ramondini, M.; Artese, S.; Floris, M.; Menin, A.; Monego, M.; Siniscalchi, V.</p> <p>2016-06-01</p> <p>The Emilia Romagna Region (N-E Italy) and in particular the Adriatic Sea coastline of Ravenna, is affected by a noticeable subsidence that started in the 1950s, when the exploitation of on and off-shore methane reservoirs began, along with the pumping of groundwater for industrial uses. In such area the current subsidence <span class="hlt">rate</span>, even if lower than in the past, reaches the -2 cm/y. Over the years, local Authorities have monitored this phenomenon with different techniques: spirit levelling, GPS surveys and, more recently, Differential Interferometric Synthetic Aperture Radar (DIn<span class="hlt">SAR</span>) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with DIn<span class="hlt">SAR</span> and GPS techniques applied to the study of the land subsidence in the Ravenna territory. With regard to the DIn<span class="hlt">SAR</span>, the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques have been used. Different <span class="hlt">SAR</span> datasets have been exploited: ERS-1/2, ENVISAT, Terra<span class="hlt">SAR</span>-X and Sentinel-1. Some GPS campaigns have been also carried out in a subsidence prone area. 3D vertices have been selected very close to existing persistent scatterers in order to link the GPS measurement results to the <span class="hlt">SAR</span> ones. GPS data were processed into the International reference system and the comparisons between the coordinates, for the first 6 months of the monitoring, provided results with the same trend of the DIn<span class="hlt">SAR</span> data, even if inside the precision of the method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.704E..23C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.704E..23C"><span id="translatedtitle">Applying Pol<span class="hlt">SAR</span> and PolIn<span class="hlt">SAR</span> to Forest Structure Information Extraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, E.; Li, Z.; Li, W.; Feng, Q.; Zhou, W.; Pottier, E.; Hong, W.</p> <p>2013-01-01</p> <p>The key research activities and achievements in the field of applying Pol<span class="hlt">SAR</span> and PolIn<span class="hlt">SAR</span> to forest structure information extraction in DRAGON 2 are summarized in this paper. The limitation of the ALOS PolIn<span class="hlt">SAR</span> dataset acquired in the Culai test site for forest height extraction because of its long temporal baseline (46 days), and how the PolIn<span class="hlt">SAR</span> coherence optimization methods can help improve the topography inversion accuracy under forest canopy were presented. We have analyzed and evaluated the capability of multiple polarization parameters extracted from different frequency Pol<span class="hlt">SAR</span> data for forest scar mapping in the Shibazhan test site, and developed the land cover classification method based on SVM (Support Vector Machine) using Pol<span class="hlt">SAR</span> data. With the L-band E-<span class="hlt">SAR</span> PolIn<span class="hlt">SAR</span> data acquired in the test site in Germany, we developed forest above ground biomass (AGB) estimation approach based on polarization coherence tomography (PCT).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1789.photos.042372p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1789.photos.042372p/"><span id="translatedtitle">5. SWITCH TOWER AND JUNCTION OF <span class="hlt">S.A.R</span>. #1 & <span class="hlt">S.A.R</span>. ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>5. SWITCH TOWER AND JUNCTION OF <span class="hlt">S.A.R</span>. #1 & <span class="hlt">S.A.R</span>. #2 TRANSMISSION LINES, MARCH 7, 1916. SCE drawing no. 4932. - Santa Ana River Hydroelectric System, Transmission Lines, Redlands, San Bernardino County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000057032','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000057032"><span id="translatedtitle">Classification of the Gabon <span class="hlt">SAR</span> Mosaic Using a Wavelet Based Rule Classifier</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Simard, Marc; Saatchi, Sasan; DeGrandi, Gianfranco</p> <p>2000-01-01</p> <p>A method is developed for semi-automated classification of <span class="hlt">SAR</span> images of the tropical forest. Information is extracted using the wavelet transform (WT). The transform allows for extraction of structural information in the image as a function of scale. In order to classify the <span class="hlt">SAR</span> image, a Desicion Tree Classifier is used. The method of pruning is used to optimize classification <span class="hlt">rate</span> versus tree size. The results give explicit insight on the type of information useful for a given class.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1177594','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1177594"><span id="translatedtitle"><span class="hlt">SAR</span> Image Complex Pixel Representations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Doerry, Armin W.</p> <p>2015-03-01</p> <p>Complex pixel values for Synthetic Aperture Radar (<span class="hlt">SAR</span>) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/929123','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/929123"><span id="translatedtitle">Reflectors for <span class="hlt">SAR</span> performance testing.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Doerry, Armin Walter</p> <p>2008-01-01</p> <p>Synthetic Aperture Radar (<span class="hlt">SAR</span>) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9829E..1LD&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9829E..1LD&link_type=ABSTRACT"><span id="translatedtitle">Representing <span class="hlt">SAR</span> complex image pixels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doerry, A. W.</p> <p>2016-05-01</p> <p>Synthetic Aperture Radar (<span class="hlt">SAR</span>) images are often complex-valued to facilitate specific exploitation modes. Furthermore, these pixel values are typically represented with either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values, with constituent components comprised of integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6698041','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6698041"><span id="translatedtitle">Thermal implications of high <span class="hlt">SAR</span>'s in the body extremities at the ANSI-recommended MF-VHF safety levels</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, J.Y.; Gandhi, O.P.</p> <p>1988-06-01</p> <p>Surface temperature elevation of the wrist and the ankle sections were measured for a healthy human subject at room temperature (22-25/sup 0/C) for a variety of RF currents and <span class="hlt">SAR</span>'s in the frequency band 1-50 MHz. The observed highest <span class="hlt">rates</span> of temperature increase in /sup 0/C/min are given by the best-fit relationships: 0.0045 x <span class="hlt">SAR</span> in W/kg for the ankle section and 0.0048 x <span class="hlt">SAR</span> for the wrist section, the latter being involved for conditions of contact with undergrounded bodies like cars, trucks, fences, etc. Since ankle-section <span class="hlt">SAR</span>'s on the order of 182-243 W/kg and wrist-section <span class="hlt">SAR</span>'s as high as 1045 W/kg have previously been projected for the E fields recommended in the ANSI C95.1-1982 safety guide, fairly high <span class="hlt">rates</span> of temperature increase are therefore anticipated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994JMRB..105..147S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994JMRB..105..147S&link_type=ABSTRACT"><span id="translatedtitle">Proton Resonance Spectroscopy Study of the Effects of L-Ornithine-L-Aspartate on the Development of Encephalopathy, Using Localization Pulses with Reduced Specific <span class="hlt">Absorption</span> <span class="hlt">Rate</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slotboom, J.; Vogels, B. A. P. M.; Dehaan, J. G.; Creyghton, J. H. N.; Quack, G.; Chamuleau, R. A. F. M.; Bovee, W. M. M. J.</p> <p></p> <p>Using the SADLOVE ( single-shot adiabatic localized volume excitation) localization technique with reduced specific <span class="hlt">absorption</span> <span class="hlt">rate</span> phase-compensated 2π pulses for localization, in vivo rat brain spectra were obtained in order to study the possible beneficial effects of L-ornithine-L-aspartate (OA) on the development of encephalopathy induced by hyperammonemia in portacaval shunted rats, an experimental model for subacute hepatic encephalopathy. The in vivo1H spectra were quantified using a conjugate-gradient-based frequency-domain fitting procedure. OA treatment resulted in an about threefold lower increase in train lactate ( P < 0.0001) and a slower increase of brain glutamine ( P = 0.022) concentration. However, these changes in brain metabolism, including a significantly lower ammonia concentration during OA treatment, were not associated with a sig significant improvement in clinical symptoms of encephalopathy, suggesting either insufficient decrease in brain ammonia concentration or another effect of OA treatment counteracting the lowering effect on blood and brain ammonia and on brain glutamine and lactate. It is concluded that localized in vivo1H MRS of the brain in combination with other analytical techniques, such as in vivo microdialysis, is helpful in explaining pathophysiological changes during hyperammonemia-induced encephalopathy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22127735','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22127735"><span id="translatedtitle">Ideal current patterns yielding optimal signal-to-noise ratio and specific <span class="hlt">absorption</span> <span class="hlt">rate</span> in magnetic resonance imaging: computational methods and physical insights.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lattanzi, Riccardo; Sodickson, Daniel K</p> <p>2012-07-01</p> <p>At high and ultra-high magnetic field strengths, understanding interactions between tissues and the electromagnetic fields generated by radiofrequency coils becomes crucial for safe and effective coil design as well as for insight into limits of performance. In this work, we present a rigorous electrodynamic modeling framework, using dyadic Green's functions, to derive the electromagnetic field in homogeneous spherical and cylindrical samples resulting from arbitrary surface currents in the presence or absence of a surrounding radiofrequency shield. We show how to calculate ideal current patterns that result in the highest possible signal-to-noise ratio (ultimate intrinsic signal-to-noise ratio) or the lowest possible radiofrequency power deposition (ultimate intrinsic specific <span class="hlt">absorption</span> <span class="hlt">rate</span>) compatible with electrodynamic principles. We identify familiar coil designs within optimal current patterns at low to moderate field strength, thereby establishing and explaining graphically the near-optimality of traditional surface and volume quadrature designs. We also document the emergence of less familiar patterns, e.g., involving substantial electric--as well as magnetic-dipole contributions, at high field strength. Performance comparisons with particular coil array configurations demonstrate that optimal performance may be approached with finite arrays if ideal current patterns are used as a guide for coil design. PMID:22127735</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4752250','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4752250"><span id="translatedtitle">Spaceborne <span class="hlt">SAR</span> Imaging Algorithm for Coherence Optimized</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Qiu, Zhiwei; Yue, Jianping; Wang, Xueqin; Yue, Shun</p> <p>2016-01-01</p> <p>This paper proposes <span class="hlt">SAR</span> imaging algorithm with largest coherence based on the existing <span class="hlt">SAR</span> imaging algorithm. The basic idea of <span class="hlt">SAR</span> imaging algorithm in imaging processing is that output signal can have maximum signal-to-noise ratio (SNR) by using the optimal imaging parameters. Traditional imaging algorithm can acquire the best focusing effect, but would bring the decoherence phenomenon in subsequent interference process. Algorithm proposed in this paper is that <span class="hlt">SAR</span> echo adopts consistent imaging parameters in focusing processing. Although the SNR of the output signal is reduced slightly, their coherence is ensured greatly, and finally the interferogram with high quality is obtained. In this paper, two scenes of Envisat ASAR data in Zhangbei are employed to conduct experiment for this algorithm. Compared with the interferogram from the traditional algorithm, the results show that this algorithm is more suitable for <span class="hlt">SAR</span> interferometry (In<span class="hlt">SAR</span>) research and application. PMID:26871446</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1178360','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1178360"><span id="translatedtitle">Building detection in <span class="hlt">SAR</span> imagery</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Steinbach, Ryan Matthew</p> <p>2015-04-01</p> <p>Current techniques for building detection in Synthetic Aperture Radar (<span class="hlt">SAR</span>) imagery can be computationally expensive and/or enforce stringent requirements for data acquisition. I present two techniques that are effective and efficient at determining an approximate building location. This approximate location can be used to extract a portion of the <span class="hlt">SAR</span> image to then perform a more robust detection. The proposed techniques assume that for the desired image, bright lines and shadows, <span class="hlt">SAR</span> artifact effects, are approximately labeled. These labels are enhanced and utilized to locate buildings, only if the related bright lines and shadows can be grouped. In order to find which of the bright lines and shadows are related, all of the bright lines are connected to all of the shadows. This allows the problem to be solved from a connected graph viewpoint, where the nodes are the bright lines and shadows and the arcs are the connections between bright lines and shadows. For the first technique, constraints based on angle of depression and the relationship between connected bright lines and shadows are applied to remove unrelated arcs. The second technique calculates weights for the connections and then performs a series of increasingly relaxed hard and soft thresholds. This results in groups of various levels on their validity. Once the related bright lines and shadows are grouped, their locations are combined to provide an approximate building location. Experimental results demonstrate the outcome of the two techniques. The two techniques are compared and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3721..170D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3721..170D"><span id="translatedtitle">Multiresolution FOPEN <span class="hlt">SAR</span> image formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DiPietro, Robert C.; Fante, Ronald L.; Perry, Richard P.; Soumekh, Mehrdad; Tromp, Laurens D.</p> <p>1999-08-01</p> <p>This paper presents a new technique for FOPEN <span class="hlt">SAR</span> (foliage penetration synthetic aperture radar) image formation of Ultra Wideband UHF radar data. Planar Subarray Processing (PSAP) has successfully demonstrated the capability of forming multi- resolution images for X and Ka band radar systems under MITRE IR&D and the DARPA IBC program. We have extended the PSAP algorithm to provide the capability to form strip map, multi- resolution images for Ultra Wideband UHF radar systems. The PSAP processing can accommodate very large <span class="hlt">SAR</span> integration angles and the resulting very large range migration. It can also accommodate long coherent integration times and wide swath coverage. Major PSAP algorithm features include: multiple <span class="hlt">SAR</span> sub-arrays providing different look angles at the same image area that can enable man-made target responses to be distinguished from other targets and clutter by their angle dependent specular characteristics, the capability to provide a full resolution image in these and other selected areas without the processing penalty of full resolution in non required areas, and the capability to include angle-dependent motion compensation within the image formation process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ESASP.731E...5W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ESASP.731E...5W&link_type=ABSTRACT"><span id="translatedtitle">In<span class="hlt">SAR</span> Forensics: Tracing In<span class="hlt">SAR</span> Scatterers in High Resolution Optical Image</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yuanyuan; Zhu, XiaoXiang</p> <p>2015-05-01</p> <p>This paper presents a step towards a better interpretation of the scattering mechanism of different objects and their deformation histories in <span class="hlt">SAR</span> interferometry (In<span class="hlt">SAR</span>). The proposed technique traces individual <span class="hlt">SAR</span> scatterer in high resolution optical images where their geometries, materials, and other properties can be better analyzed and classified. And hence scatterers of a same object can be analyzed in group, which brings us to a new level of In<span class="hlt">SAR</span> deformation monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1710313D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1710313D&link_type=ABSTRACT"><span id="translatedtitle">Comparing The Results Of Terrasar-X And Envisat <span class="hlt">Sar</span> Images With Ps-In<span class="hlt">SAR</span> Methods On Slow Motion Landslides: Koyulhisar, Turkey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Demirel, Mehmet; Poyraz, Fatih; Özgür Hastaoğlu, Kemal; Türk, Tarık; Tatar, Orhan; Birdal, Anıl Can</p> <p>2015-04-01</p> <p>In recent years, PS-In<span class="hlt">SAR</span> method has been used widely on monitoring slow motion landslides. The motion amounts obtained by PS-In<span class="hlt">SAR</span> method is avaliable only in LOS(line of sight) and it can't provide information about three dimensional motions. Nevertheless, motions caused by landslides are usually 3 dimensional and also they are not homogeneous. This is one of the biggest handicaps of monitoring landslides with <span class="hlt">SAR</span> method. In this study, annual motion <span class="hlt">rates</span> of the PS points that are located in Koyulhisar landslide region are obtained from differently resolutioned <span class="hlt">sar</span> images of Envisat and Terrasar-x satellite's frames through PS-In<span class="hlt">SAR</span> method and by using StaMPS software. Throughout the landslide region a profile has been established in North-South line, and the correlation of the results obtained from the <span class="hlt">sar</span> images lining on this profile. All results are observed to have %80 correlation with each other. By means of these results a subsidence area has been found in the northern region and an uplifting area has been found in the southern region. Through this study, general information about the landslide mechanism has been obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19396666','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19396666"><span id="translatedtitle">Determining <span class="hlt">SARS</span> sub-clinical infection: a longitudinal seroepidemiological study in recovered <span class="hlt">SARS</span> patients and controls after an outbreak in a general hospital.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Zhen; Wang, Shixin; Li, Qian; Li, Yuming; Wei, Maoti; Gao, Hongsheng; Donovan, Catherine; Wang, Peizhong Peter</p> <p>2009-01-01</p> <p>A cohort of 67 confirmed <span class="hlt">SARS</span> patients were prospectively followed for 16 months and were compared with a control population. Serum samples taken at various times were tested for IgG and IgM; dynamic serological changes in these antibodies were described. The positive responses of IgM and IgG antibodies in sera against <span class="hlt">SARS</span> virus from the first week to the sixth week after onset of the illness in patients with <span class="hlt">SARS</span> were measured. The ELISA test of IgG antibody was negative in 200 community controls. The positive <span class="hlt">rate</span> in the <span class="hlt">SARS</span> high-risk population was 0.61% tested by ELISA and 0.21% by IFA. The high-risk population in this study was defined as those who provided health care and other services to <span class="hlt">SARS</span> patients during the outbreak. IgG antibody in convalescent serum of patients with <span class="hlt">SARS</span> revealed an increasing trend, peaking at the 22nd week after onset of illness followed by a slow decline. IgM appeared earlier than IgG and can be better used for early detection. IgG remained at a high level for a much longer period, serving as a good indicator for follow-up and for assessing past exposure. Our results also suggest that sub-clinical infection, if it exists, is very rare. PMID:19396666</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.720E..51G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.720E..51G"><span id="translatedtitle">A Modular and Configurable Instrument Electronics Architecture for "Mini<span class="hlt">SAR</span>"- An Advanced Smallsat <span class="hlt">SAR</span> Instrument</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez, Jaime; Pastena, Max; Bierens, Laurens</p> <p>2013-08-01</p> <p>Mini<span class="hlt">SAR</span> is a Dutch program focused on the development of a commercial smallsat featuring a <span class="hlt">SAR</span> instrument, led by SSBV as prime contractor. In this paper an Instrument Electronics (IEL) system concept to meet the Mini<span class="hlt">SAR</span> demands is presented. This system has several specificities wrt similar initiatives in the European space industry, driven by our main requirement: keep it small.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PMB....61.2991K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PMB....61.2991K&link_type=ABSTRACT"><span id="translatedtitle">Large scale study on the variation of RF energy <span class="hlt">absorption</span> in the head & brain regions of adults and children and evaluation of the SAM phantom conservativeness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keshvari, J.; Kivento, M.; Christ, A.; Bit-Babik, G.</p> <p>2016-04-01</p> <p>This paper presents the results of two computational large scale studies using highly realistic exposure scenarios, MRI based human head and hand models, and two mobile phone models. The objectives are (i) to study the relevance of age when people are exposed to RF by comparing adult and child heads and (ii) to analyze and discuss the conservativeness of the SAM phantom for all age groups. Representative use conditions were simulated using detailed CAD models of two mobile phones operating between 900 MHz and 1950 MHz including configurations with the hand holding the phone, which were not considered in most previous studies. The peak spatial-average specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (ps<span class="hlt">SAR</span>) in the head and the pinna tissues is assessed using anatomically accurate head and hand models. The first of the two mentioned studies involved nine head-, four hand- and two phone-models, the second study included six head-, four hand- and three simplified phone-models (over 400 configurations in total). In addition, both studies also evaluated the exposure using the SAM phantom. Results show no systematic differences between ps<span class="hlt">SAR</span> induced in the adult and child heads. The exposure level and its variation for different age groups may be different for particular phones, but no correlation between ps<span class="hlt">SAR</span> and model age was found. The ps<span class="hlt">SAR</span> from all exposure conditions was compared to the corresponding configurations using SAM, which was found to be conservative in the large majority of cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011440','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011440"><span id="translatedtitle">High resolution <span class="hlt">SAR</span> applications and instrument design</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dionisio, C.; Torre, A.</p> <p>1993-01-01</p> <p>The Synthetic Aperture Radar (<span class="hlt">SAR</span>) has viewed, in the last two years, a huge increment of interest from many preset and potential users. The good spatial resolution associated to the all weather capability lead to considering <span class="hlt">SAR</span> not only a scientific instrument but a tool for verifying and controlling the daily human relationships with the Earth Environment. New missions were identified for <span class="hlt">SAR</span> as spatial resolution became lower than three meters: disasters, pollution, ships traffic, volcanic eruptions, earthquake effect are only a few of the possible objects which can be effectively detected, controlled and monitored by <span class="hlt">SAR</span> mounted on satellites. High resolution radar design constraints and dimensioning are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1159449','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1159449"><span id="translatedtitle">Bistatic <span class="hlt">SAR</span>: Signal Processing and Image Formation.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wahl, Daniel E.; Yocky, David A.</p> <p>2014-10-01</p> <p>This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (<span class="hlt">SAR</span>) hardware built for the NCNS Bistatic <span class="hlt">SAR</span> project to a final bistatic <span class="hlt">SAR</span> image. In general, the process steps herein are applicable to bistatic <span class="hlt">SAR</span> signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013 on Kirtland Air Force Base, New Mexico.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032497','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032497"><span id="translatedtitle">Mapping ground surface deformation using temporarily coherent point <span class="hlt">SAR</span> interferometry: Application to Los Angeles Basin</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zhang, L.; Lu, Zhiming; Ding, X.; Jung, H.-S.; Feng, G.; Lee, C.-W.</p> <p>2012-01-01</p> <p>Multi-temporal interferometric synthetic aperture radar (In<span class="hlt">SAR</span>) is an effective tool to detect long-term seismotectonic motions by reducing the atmospheric artifacts, thereby providing more precise deformation signal. The commonly used approaches such as persistent scatterer In<span class="hlt">SAR</span> (PSIn<span class="hlt">SAR</span>) and small baseline subset (SBAS) algorithms need to resolve the phase ambiguities in interferogram stacks either by searching a predefined solution space or by sparse phase unwrapping methods; however the efficiency and the success of phase unwrapping cannot be guaranteed. We present here an alternative approach - temporarily coherent point (TCP) In<span class="hlt">SAR</span> (TCPIn<span class="hlt">SAR</span>) - to estimate the long term deformation <span class="hlt">rate</span> without the need of phase unwrapping. The proposed approach has a series of innovations including TCP identification, TCP network and TCP least squares estimator. We apply the proposed method to the Los Angeles Basin in southern California where structurally active faults are believed capable of generating damaging earthquakes. The analysis is based on 55 interferograms from 32 ERS-1/2 images acquired during Oct. 1995 and Dec. 2000. To evaluate the performance of TCPIn<span class="hlt">SAR</span> on a small set of observations, a test with half of interferometric pairs is also performed. The retrieved TCPIn<span class="hlt">SAR</span> measurements have been validated by a comparison with GPS observations from Southern California Integrated GPS Network. Our result presents a similar deformation pattern as shown in past In<span class="hlt">SAR</span> studies but with a smaller average standard deviation (4.6. mm) compared with GPS observations, indicating that TCPIn<span class="hlt">SAR</span> is a promising alternative for efficiently mapping ground deformation even from a relatively smaller set of interferograms. ?? 2011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3747523','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3747523"><span id="translatedtitle">From <span class="hlt">SARS</span> coronavirus to novel animal and human coronaviruses</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>To, Kelvin K. W.; Hung, Ivan F. N.; Chan, Jasper F. W.</p> <p>2013-01-01</p> <p>In 2003, severe acute respiratory syndrome coronavirus (<span class="hlt">SARS</span>-CoV) caused one of the most devastating epidemics known to the developed world. There were two important lessons from this epidemic. Firstly, coronaviruses, in addition to influenza viruses, can cause severe and rapidly spreading human infections. Secondly, bats can serve as the origin and natural animal reservoir of deadly human viruses. Since then, researchers around the world, especially those in Asia where <span class="hlt">SARS</span>-CoV was first identified, have turned their focus to find novel coronaviruses infecting humans, bats, and other animals. Two human coronaviruses, HCoV-HKU1 and HCoV-NL63, were identified shortly after the <span class="hlt">SARS</span>-CoV epidemic as common causes of human respiratory tract infections. In 2012, a novel human coronavirus, now called Middle East respiratory syndrome coronavirus (MERS-CoV), has emerged in the Middle East to cause fatal human infections in three continents. MERS-CoV human infection is similar to <span class="hlt">SARS</span>-CoV in having a high fatality <span class="hlt">rate</span> and the ability to spread from person to person which resulted in secondary cases among close contacts including healthcare workers without travel history to the Middle East. Both viruses also have close relationships with bat coronaviruses. New cases of MERS-CoV infection in humans continue to occur with the origins of the virus still unknown in many cases. A multifaceted approach is necessary to control this evolving MERS-CoV outbreak. Source identification requires detailed epidemiological studies of the infected patients and enhanced surveillance of MERS-CoV or similar coronaviruses in humans and animals. Early diagnosis of infected patients and appropriate infection control measures will limit the spread in hospitals, while social distancing strategies may be necessary to control the outbreak in communities if it remained uncontrolled as in the <span class="hlt">SARS</span> epidemic. PMID:23977429</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.8387S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.8387S"><span id="translatedtitle">Vertical ground movements for Prague and Ostrava-Karviná areas determined by PSIn<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schenk, V.; Wegmüller, U.; Kadlecik, P.; Schenkova, Z.</p> <p>2009-04-01</p> <p>Permanent Scatterers Interferometry <span class="hlt">SAR</span> (PSIn<span class="hlt">SAR</span>) allows precise measurements of ground movements to be detected. This remote sensing technique assesses displacements along the satellite line of sight and detects vertical movements of targets on the Earth surface (called permanent scatterers). They are representing particularly by man-made objects (e.g. individual buildings) and by rock outcrops in a landscape. For area of Prague were processed 78 ERS1/2 <span class="hlt">SAR</span> scenes for period from 1992 to 2005. Subsidence and uplift <span class="hlt">rates</span> in the Prague area reach millimetres to centimetres per year. The PSIn<span class="hlt">SAR</span> analysis identifies primarily vertical movements of local significance, mostly subsiding of buildings and/or object complexes in the urban area. The second investigated Ostrava-Karviná area is heavily affected by long-term undermining activities. The PSIn<span class="hlt">SAR</span> data for this area relate to the 1995-2000 period (acquired by processing ERS1/2 48 <span class="hlt">SAR</span> scenes). Displacements for the urban area of Ostrava town display subsiding effects, because of coal-mining decrease, while in the Karviná coal mining area they are still in a progress. Some areas located in the undermined region move down up to several decimetres per year. Detectable <span class="hlt">rate</span> of vertical movement obtained by the PSIn<span class="hlt">SAR</span> application reaches at most 1.5 centimetres per year. Since in a few locations <span class="hlt">rates</span> of movements are rather high, three scenes from 2007 by differential interferometry <span class="hlt">SAR</span> were processed using the ALOS PALSAR approach to determine these intensive movements. The work was supported by the Targeted Research Programme of the Academy of Sciences of the Czech Republic (1QS300460551) and by Ministry of Education, Youth and Sport of the Czech Republic (LC506).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16121463','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16121463"><span id="translatedtitle">Three-dimensional surface reconstruction from multistatic <span class="hlt">SAR</span> images.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rigling, Brian D; Moses, Randolph L</p> <p>2005-08-01</p> <p>This paper discusses reconstruction of three-dimensional surfaces from multiple bistatic synthetic aperture radar (<span class="hlt">SAR</span>) images. Techniques for surface reconstruction from multiple monostatic <span class="hlt">SAR</span> images already exist, including interferometric processing and stereo <span class="hlt">SAR</span>. We generalize these methods to obtain algorithms for bistatic interferometric <span class="hlt">SAR</span> and bistatic stereo <span class="hlt">SAR</span>. We also propose a framework for predicting the performance of our multistatic stereo <span class="hlt">SAR</span> algorithm, and, from this framework, we suggest a metric for use in planning strategic deployment of multistatic assets. PMID:16121463</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16485757','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16485757"><span id="translatedtitle">Capacitive-loaded interstitial antennas for perfect matching and desirable <span class="hlt">SAR</span> distributions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahn, Hee-Ran; Lee, Kwyro</p> <p>2006-02-01</p> <p>New interstitial antennas are proposed. They basically consist of coaxial cable and two types of capacitive loads. One is tipped at the end of antennas, which helps almost perfect matching possible. The others are located in the middle and needed for better specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) distribution. To distinguish them, one at the end is called the end-capacitive load (ECL) and the others in the middle the middle-capacitive loads (MCLs). Depending on the number of the MCLs, ZMIA (zero MCL interstitial antenna), OMIA (one MCL interstitial antenna) and two MCL interstitial antenna (TMIA) are named and a matching technique based on transmission line theory is suggested. To verify the technique, the three antennas immersed in muscle phantom are designed, fabricated, measured and compared. The measured reflection coefficients of ZMIA, OMIA, and TMIA are -28.4, -21.9, and -22.8 dB, respectively, one of which, -28.4 dB may be considered as the best among those reported. The compared results show that the measured ones are in good agreement with the calculated (predicted) ones. The three antennas are also measured for the <span class="hlt">SAR</span> distributions. The measured results indicate that the TMIA has the best performance as expected and the region more than 43 degrees C is a rugby ball (major axis 6 cm and minor axis 2.9 cm) with only one TMIA, which confirms that they may be used for the treatment for big-sized and deep-seated tumor or cancer. PMID:16485757</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70036636','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70036636"><span id="translatedtitle">Helmand river hydrologic studies using ALOS PALSAR In<span class="hlt">SAR</span> and ENVISAT altimetry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lu, Zhiming; Kim, J.-W.; Lee, H.; Shum, C.K.; Duan, J.; Ibaraki, M.; Akyilmaz, O.; Read, C.-H.</p> <p>2009-01-01</p> <p>The Helmand River wetland represents the only fresh-water resource in southern Afghanistan and one of the least mapped water basins in the world. The relatively narrow wetland consists of mostly marshes surrounded by dry lands. In this study, we demonstrate the use of the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) Interferometric <span class="hlt">SAR</span> (In<span class="hlt">SAR</span>) to detect the changes of the Helmand River wetland water level. In<span class="hlt">SAR</span> images are combined with the geocentric water level measurements from the retracked high-<span class="hlt">rate</span> (18-Hz) Environmental Satellite (Envisat) radar altimetry to construct absolute water level changes over the marshes. It is demonstrated that the integration of the altimeter and In<span class="hlt">SAR</span> can provide spatio-temporal measurements of water level variation over the Helmand River marshes where in situ measurements are absent. ?? Taylor & Francis Group, LLC.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034143','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034143"><span id="translatedtitle">SBAS-In<span class="hlt">SAR</span> analysis of surface deformation at Mauna Loa and Kilauea volcanoes in Hawaii</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Casu, F.; Lanari, Riccardo; Sansosti, E.; Solaro, G.; Tizzani, Pietro; Poland, M.; Miklius, Asta</p> <p>2009-01-01</p> <p>We investigate the deformation of Mauna Loa and K??lauea volcanoes, Hawai'i, by exploiting the advanced differential Synthetic Aperture Radar Interferometry (In<span class="hlt">SAR</span>) technique referred to as the Small BAseline Subset (SBAS) algorithm. In particular, we present time series of line-of-sight (LOS) displacements derived from <span class="hlt">SAR</span> data acquired by the ASAR instrument, on board the ENVISAT satellite, from the ascending (track 93) and descending (track 429) orbits between 2003 and 2008. For each coherent pixel of the radar images we compute time-dependent surface displacements as well as the average LOS deformation <span class="hlt">rate</span>. Our results quantify, in space and time, the complex deformation of Mauna Loa and K??lauea volcanoes. The derived In<span class="hlt">SAR</span> measurements are compared to continuous GPS data to asses the quality of the SBAS-In<span class="hlt">SAR</span> products. ??2009 IEEE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SPIE.5236....1W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SPIE.5236....1W"><span id="translatedtitle">InfoTerra/Terra<span class="hlt">SAR</span> initiative</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, Manfred W.</p> <p>2004-01-01</p> <p>The overarching goal of the InfoTerra/Terra<span class="hlt">SAR</span> Initiative is to establish a self-sustaining operational/commercial business built on Europe"s know-how and experience in space-borne Synthetic Aperture Radar (<span class="hlt">SAR</span>) technology, in <span class="hlt">SAR</span> data processing as well as in <span class="hlt">SAR</span> applications. InfoTerra stands for a new business concept based on supplying innovative geo-information products and services. Terra<span class="hlt">SAR</span> is a space and ground system conceived to consist of an initial deployment and operation of 2 Radar satellites (one in X- and one in L-band) flying in a tandem configuration in the same orbit. The design of Terra<span class="hlt">SAR</span> is driven by the market and is user-oriented. Terra<span class="hlt">SAR</span> is key to capturing a significant proportion of the existing market and to opening new market opportunities, when it becomes operational. The InfoTerra/Terra<span class="hlt">SAR</span> Initiative has evolved gradually. It started in 1997 as a joint venture between German (DSS) and British (MMS-UK) space industry, strongly supported by both space agencies, DLR and BNSC. In early 2001, DLR and BNSC submitted to ESA the Formal Programme Proposal for InfoTerra/Terra<span class="hlt">SAR</span> to become an essential element of ESA"s Earth Watch Programme. In summer 2001, when it became evident that there was not yet sufficient support from the ESA Member States to allow immediate start entering into Terra<span class="hlt">SAR</span> Phase C/D, it has been decided to implement first a Terra<span class="hlt">SAR</span> consolidation phase. In early 2002, in order to avoid further delays, a contract was signed between DLR and Astrium GmbH on the development of one component of Terra<span class="hlt">SAR</span>, the Terra<span class="hlt">SAR</span>-X, in the frame of a national programme, governed by a Public Private Partnership Agreement. Even if now the different launch dates for Terra<span class="hlt">SAR</span>-X and Terra<span class="hlt">SAR</span>-L are narrowing down the window of common data acquisition, it is a reasonable starting point, but it should always be kept in mind that the utmost goal for the longterm is to achieve self sustainability by supplying geo-information products and services</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27052877','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27052877"><span id="translatedtitle">Population Pharmacokinetics of Oral Topotecan in Infants and Very Young Children with Brain Tumors Demonstrates a Role of ABCG2 rs4148157 on the <span class="hlt">Absorption</span> <span class="hlt">Rate</span> Constant.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roberts, Jessica K; Birg, Anna V; Lin, Tong; Daryani, Vinay M; Panetta, John C; Broniscer, Alberto; Robinson, Giles W; Gajjar, Amar J; Stewart, Clinton F</p> <p>2016-07-01</p> <p>For infants and very young children with brain tumors, chemotherapy after surgical resection is the main treatment due to neurologic and neuroendocrine adverse effects from whole brain irradiation. Topotecan, an anticancer drug with antitumor activity against pediatric brain tumors, can be given intravenous or orally. However, high interpatient variability in oral drug bioavailability is common in children less than 3 years old. Therefore, this study aimed to determine the population pharmacokinetics of oral topotecan in infants and very young children, specifically evaluating the effects of age and ABCG2 and ABCB1 on the <span class="hlt">absorption</span> <span class="hlt">rate</span> constant (Ka), as well as other covariate effects on all pharmacokinetic parameters. A nonlinear mixed effects model was implemented in Monolix 4.3.2 (Lixoft, Orsay, France). A one-compartment model with first-order input and first-order elimination was found to adequately characterize topotecan lactone concentrations with population estimates as [mean (S.E.)]; Ka = 0.61 (0.11) h(-1), apparent volume of distribution (V/F) = 40.2 (7.0) l, and apparent clearance (CL/F) = 40.0 (2.9) l/h. After including the body surface area in the V/F and CL/F as a power model centered on the population median, the ABCG2 rs4148157 allele was found to play a significant role in the value of Ka Patients homozygous or heterozygous for G>A demonstrated a Ka value 2-fold higher than their GG counterparts, complemented with a 2-fold higher maximal concentration as well. These results demonstrate a possible role for the ABCG2 rs4148157 allele in the pharmacokinetics of oral topotecan in infants and very young children, and warrants further investigation. PMID:27052877</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19497090','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19497090"><span id="translatedtitle">Bats and emerging zoonoses: henipaviruses and <span class="hlt">SARS</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Field, H E</p> <p>2009-08-01</p> <p>Nearly 75% of all emerging infectious diseases (EIDs) that impact or threaten human health are zoonotic. The majority have spilled from wildlife reservoirs, either directly to humans or via domestic animals. The emergence of many can be attributed to predisposing factors such as global travel, trade, agricultural expansion, deforestation/habitat fragmentation, and urbanization; such factors increase the interface and/or the <span class="hlt">rate</span> of contact between human, domestic animal, and wildlife populations, thereby creating increased opportunities for spillover events to occur. Infectious disease emergence can be regarded as primarily an ecological process. The epidemiological investigation of EIDs associated with wildlife requires a trans-disciplinary approach that includes an understanding of the ecology of the wildlife species, and an understanding of human behaviours that increase risk of exposure. Investigations of the emergence of Nipah virus in Malaysia in 1999 and severe acute respiratory syndrome (<span class="hlt">SARS</span>) in China in 2003 provide useful case studies. The emergence of Nipah virus was associated with the increased size and density of commercial pig farms and their encroachment into forested areas. The movement of pigs for sale and slaughter in turn led to the rapid spread of infection to southern peninsular Malaysia, where the high-density, largely urban pig populations facilitated transmission to humans. Identifying the factors associated with the emergence of <span class="hlt">SARS</span> in southern China requires an understanding of the ecology of infection both in the natural reservoir and in secondary market reservoir species. A necessary extension of understanding the ecology of the reservoir is an understanding of the trade, and of the social and cultural context of wildlife consumption. Emerging infectious diseases originating from wildlife populations will continue to threaten public health. Mitigating and managing the risk requires an appreciation of the connectedness between human</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15809906','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15809906"><span id="translatedtitle">Detection of airborne severe acute respiratory syndrome (<span class="hlt">SARS</span>) coronavirus and environmental contamination in <span class="hlt">SARS</span> outbreak units.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Booth, Timothy F; Kournikakis, Bill; Bastien, Nathalie; Ho, Jim; Kobasa, Darwyn; Stadnyk, Laurie; Li, Yan; Spence, Mel; Paton, Shirley; Henry, Bonnie; Mederski, Barbara; White, Diane; Low, Donald E; McGeer, Allison; Simor, Andrew; Vearncombe, Mary; Downey, James; Jamieson, Frances B; Tang, Patrick; Plummer, Frank</p> <p>2005-05-01</p> <p>Severe acute respiratory syndrome (<span class="hlt">SARS</span>) is characterized by a risk of nosocomial transmission; however, the risk of airborne transmission of <span class="hlt">SARS</span> is unknown. During the Toronto outbreaks of <span class="hlt">SARS</span>, we investigated environmental contamination in <span class="hlt">SARS</span> units, by employing novel air sampling and conventional surface swabbing. Two polymerase chain reaction (PCR)-positive air samples were obtained from a room occupied by a patient with <span class="hlt">SARS</span>, indicating the presence of the virus in the air of the room. In addition, several PCR-positive swab samples were recovered from frequently touched surfaces in rooms occupied by patients with <span class="hlt">SARS</span> (a bed table and a television remote control) and in a nurses' station used by staff (a medication refrigerator door). These data provide the first experimental confirmation of viral aerosol generation by a patient with <span class="hlt">SARS</span>, indicating the possibility of airborne droplet transmission, which emphasizes the need for adequate respiratory protection, as well as for strict surface hygiene practices. PMID:15809906</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1714846B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1714846B&link_type=ABSTRACT"><span id="translatedtitle">Sentinel-3 <span class="hlt">SAR</span> Altimetry Toolbox</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benveniste, Jerome; Lucas, Bruno; DInardo, Salvatore</p> <p>2015-04-01</p> <p>The prime objective of the SEOM (Scientific Exploitation of Operational Missions) element is to federate, support and expand the large international research community that the ERS, ENVISAT and the Envelope programmes have build up over the last 20 years for the future European operational Earth Observation missions, the Sentinels. Sentinel-3 builds directly on a proven heritage of ERS-2 and Envisat, and CryoSat-2, with a dual-frequency (Ku and C band) advanced Synthetic Aperture Radar Altimeter (SRAL) that provides measurements at a resolution of ~300m in <span class="hlt">SAR</span> mode along track. Sentinel-3 will provide exact measurements of sea-surface height along with accurate topography measurements over sea ice, ice sheets, rivers and lakes. The first of the two Sentinels is expected to be launched in early 2015. The current universal altimetry toolbox is BRAT (Basic Radar Altimetry Toolbox) which can read all previous and current altimetry mission's data, but it does not have the capabilities to read the upcoming Sentinel-3 L1 and L2 products. ESA will endeavour to develop and supply this capability to support the users of the future Sentinel-3 <span class="hlt">SAR</span> Altimetry Mission. BRAT is a collection of tools and tutorial documents designed to facilitate the processing of radar altimetry data. This project started in 2005 from the joint efforts of ESA (European Space Agency) and CNES (Centre National d'Etudes Spatiales), and it is freely available at http://earth.esa.int/brat. The tools enable users to interact with the most common altimetry data formats, the BratGUI is the front-end for the powerful command line tools that are part of the BRAT suite. BRAT can also be used in conjunction with Matlab/IDL (via reading routines) or in C/C++/Fortran via a programming API, allowing the user to obtain desired data, bypassing the data-formatting hassle. BRAT can be used simply to visualise data quickly, or to translate the data into other formats such as netCDF, ASCII text files, KML (Google Earth</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930054250&hterms=terrestre&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dterrestre','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930054250&hterms=terrestre&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dterrestre"><span id="translatedtitle">Cross-calibration between airborne <span class="hlt">SAR</span> sensors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zink, Manfred; Olivier, Philippe; Freeman, Anthony</p> <p>1993-01-01</p> <p>As Synthetic Aperture Radar (<span class="hlt">SAR</span>) system performance and experience in <span class="hlt">SAR</span> signature evaluation increase, quantitative analysis becomes more and more important. Such analyses require an absolute radiometric calibration of the complete <span class="hlt">SAR</span> system. To keep the expenditure on calibration of future multichannel and multisensor remote sensing systems (e.g., X-<span class="hlt">SAR</span>/SIR-C) within a tolerable level, data from different tracks and different sensors (channels) must be cross calibrated. The 1989 joint E-<span class="hlt">SAR</span>/DC-8 <span class="hlt">SAR</span> calibration campaign gave a first opportunity for such an experiment, including cross sensor and cross track calibration. A basic requirement for successful cross calibration is the stability of the <span class="hlt">SAR</span> systems. The calibration parameters derived from different tracks and the polarimetric properties of the uncalibrated data are used to describe this stability. Quality criteria for a successful cross calibration are the agreement of alpha degree values and the consistency of radar cross sections of equally sized corner reflectors. Channel imbalance and cross talk provide additional quality in case of the polarimetric DC-8 <span class="hlt">SAR</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=ordinary+AND+equation&pg=4&id=EJ728200','ERIC'); return false;" href="http://eric.ed.gov/?q=ordinary+AND+equation&pg=4&id=EJ728200"><span id="translatedtitle">A Simple Model for a <span class="hlt">SARS</span> Epidemic</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ang, Keng Cheng</p> <p>2004-01-01</p> <p>In this paper, we examine the use of an ordinary differential equation in modelling the <span class="hlt">SARS</span> outbreak in Singapore. The model provides an excellent example of using mathematics in a real life situation. The mathematical concepts involved are accessible to students with A level Mathematics backgrounds. Data for the <span class="hlt">SARS</span> epidemic in Singapore are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987SPIE..786..206W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987SPIE..786..206W"><span id="translatedtitle">Knowledge based <span class="hlt">SAR</span> images exploitations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, David L.</p> <p>1987-01-01</p> <p>One of the basic functions of <span class="hlt">SAR</span> images exploitation system is the detection of man-made objects. The performance of object detection is strongly limited by performance of segmentation modules. This paper presents a detection paradigm composed of an adaptive segmentation algorithm based on a priori knowledge of objects followed by a top-down hierarchical detection process that generates and evaluates object hypotheses. Shadow information and inter-object relationships can be added to the knowledge base to improve performance over that of a statistical detector based only on the attributes of individual objects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/800817','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/800817"><span id="translatedtitle">Regularization Analysis of <span class="hlt">SAR</span> Superresolution</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>DELAURENTIS,JOHN M.; DICKEY,FRED M.</p> <p>2002-04-01</p> <p>Superresolution concepts offer the potential of resolution beyond the classical limit. This great promise has not generally been realized. In this study we investigate the potential application of superresolution concepts to synthetic aperture radar. The analytical basis for superresolution theory is discussed. In a previous report the application of the concept to synthetic aperture radar was investigated as an operator inversion problem. Generally, the operator inversion problem is ill posed. This work treats the problem from the standpoint of regularization. Both the operator inversion approach and the regularization approach show that the ability to superresolve <span class="hlt">SAR</span> imagery is severely limited by system noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900000169&hterms=intervention+mapping&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dintervention%2Bmapping','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900000169&hterms=intervention+mapping&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dintervention%2Bmapping"><span id="translatedtitle">Making Mosaics Of <span class="hlt">SAR</span> Imagery</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curlander, John C.; Kwok, Ronald; Pang, Shirley S.; Pang, Amy A.</p> <p>1990-01-01</p> <p>Spaceborne synthetic-aperture-radar (<span class="hlt">SAR</span>) images useful for mapping of planets and investigations in Earth sciences. Produces multiframe mosaic by combining images along ground track, in adjacent cross-track swaths, or in ascending and descending passes. Images registered with geocoded maps such as ones produced by MAPJTC (NPO-17718), required as input. Minimal intervention by operator required. MOSK implemented on DEC VAX 11/785 computer running VMS 4.5. Most subroutines in FORTRAN, but three in MAXL and one in APAL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18285213','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18285213"><span id="translatedtitle">Reconnaissance with slant plane circular <span class="hlt">SAR</span> imaging.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Soumekh, M</p> <p>1996-01-01</p> <p>This paper presents a method for imaging from the slant plane data collected by a synthetic aperture radar (<span class="hlt">SAR</span>) over the full rotation or a partial segment of a circular flight path. A Fourier analysis for the Green's function of the imaging system is provided. This analysis is the basis of an inversion for slant plane circular <span class="hlt">SAR</span> data. The reconstruction algorithm and resolution for this <span class="hlt">SAR</span> system are outlined. It is shown that the slant plane circular <span class="hlt">SAR</span>, unlike the slant plane linear <span class="hlt">SAR</span>, has the capability to extract three-dimensional imaging information of a target scene. The merits of the algorithm are demonstrated via a simulated target whose ultra wideband foliage penetrating (FOPEN) or ground penetrating (GPEN) ultrahigh frequency (UHF) radar signature varies with the radar's aspect angle. PMID:18285213</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH51D1922W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH51D1922W"><span id="translatedtitle">In<span class="hlt">SAR</span> and Numeric Modeling for Land Subsidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wulamu, A.; Grzovic, M.</p> <p>2015-12-01</p> <p>Monitoring land subsidence due to coal mining is a function of several controlling factors, including: depth of the mine, stratigraphy, presence or absence of faults, thickness of mineral seam, mining method used, and hydrogeological conditions. Numerical modeling, e.g., finite element modeling (FEM), provides a comprehensive tool to simulate three-dimensional deformation at specific locations. The basis of the FEM is the representation of a body or a structure by an assemblage of subdivisions called finite elements, which requires the availability of site specific environmental and physical characteristics. The lack of availability of the necessary data leads to large uncertainties in subsidence estimates. With the use of In<span class="hlt">SAR</span>, many of the needed controlling parameters for improving mine subsidence <span class="hlt">rate</span> estimates can be identified. Coupling In<span class="hlt">SAR</span> with FEM can further improve subsidence <span class="hlt">rate</span> estimates through additional analysis yielding information on the relative importance of various controlling parameters contributing to the mine subsidence, the key mechanisms of failure associated with these parameters, and the surface expressions of these processes. In this contribution, we show that utilizing In<span class="hlt">SAR</span> and FEM leads to an overall enhanced understanding of mine behavior, including the physical mechanisms that lead to mine subsidence through understanding the rheological behavior of the material over the mine in response to wide range of physical and environmental conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27344959','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27344959"><span id="translatedtitle"><span class="hlt">SARS</span> and MERS: recent insights into emerging coronaviruses.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de Wit, Emmie; van Doremalen, Neeltje; Falzarano, Darryl; Munster, Vincent J</p> <p>2016-08-01</p> <p>The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 marked the second introduction of a highly pathogenic coronavirus into the human population in the twenty-first century. The continuing introductions of MERS-CoV from dromedary camels, the subsequent travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality <span class="hlt">rates</span> highlight the need for prophylactic and therapeutic measures. Scientific advancements since the 2002-2003 severe acute respiratory syndrome coronavirus (<span class="hlt">SARS</span>-CoV) pandemic allowed for rapid progress in our understanding of the epidemiology and pathogenesis of MERS-CoV and the development of therapeutics. In this Review, we detail our present understanding of the transmission and pathogenesis of <span class="hlt">SARS</span>-CoV and MERS-CoV, and discuss the current state of development of measures to combat emerging coronaviruses. PMID:27344959</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3323212','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3323212"><span id="translatedtitle">Clinical Manifestations, Laboratory Findings, and Treatment Outcomes of <span class="hlt">SARS</span> Patients</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Jann-Tay; Sheng, Wang-Huei; Fang, Chi-Tai; Chen, Yee-Chun; Wang, Jiun-Ling; Yu, Chong-Jen; Yang, Pan-Chyr</p> <p>2004-01-01</p> <p>Clinical and laboratory data on severe acute respiratory syndrome (<span class="hlt">SARS</span>), particularly on the temporal progression of abnormal laboratory findings, are limited. We conducted a prospective study on the clinical, radiologic, and hematologic findings of <span class="hlt">SARS</span> patients with pneumonia, who were admitted to National Taiwan University Hospital from March 8 to June 15, 2003. Fever was the most frequent initial symptom, followed by cough, myalgia, dyspnea, and diarrhea. Twenty-four patients had various underlying diseases. Most patients had elevated C-reactive protein (CRP) levels and lymphopenia. Other common abnormal laboratory findings included leukopenia, thrombocytopenia, and elevated levels of aminotransferase, lactate dehydrogenase, and creatine kinase. These clinical and laboratory findings were exacerbated in most patients during the second week of disease. The overall case-fatality <span class="hlt">rate</span> was 19.7%. By multivariate analysis, underlying disease and initial CRP level were predictive of death. PMID:15200814</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060041245&hterms=EXTRACTION+OIL&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEXTRACTION%2BOIL','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060041245&hterms=EXTRACTION+OIL&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEXTRACTION%2BOIL"><span id="translatedtitle">Rapid subsidence over oil fields measured by <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fielding, E. J.; Blom, R. G.; Goldstein, R. M.</p> <p>1998-01-01</p> <p>The Lost Hills and Belridge oil felds are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface subsidence bowl. We measure this subsidence from space using interferometric analysis of <span class="hlt">SAR</span> (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence <span class="hlt">rates</span> are as high as 40 mm in 35 days or > 400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month interferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS <span class="hlt">SAR</span>, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17033296','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17033296"><span id="translatedtitle">Cholesterol <span class="hlt">absorption</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ostlund, Richard E</p> <p>2002-03-01</p> <p>Cholesterol <span class="hlt">absorption</span> is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol <span class="hlt">absorption</span> and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol <span class="hlt">absorption</span> is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol <span class="hlt">absorption</span> when dietary intake is high. New clinical treatments based on better understanding of <span class="hlt">absorption</span> physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1550560','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1550560"><span id="translatedtitle"><span class="hlt">SARS</span> and Population Health Technology</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2003-01-01</p> <p>The recent global outbreak of <span class="hlt">SARS</span> (severe acute respiratory syndrome) provides an opportunity to study the use and impact of public health informatics and population health technology to detect and fight a global epidemic. Population health technology is the umbrella term for technology applications that have a population focus and the potential to improve public health. This includes the Internet, but also other technologies such as wireless devices, mobile phones, smart appliances, or smart homes. In the context of an outbreak or bioterrorism attack, such technologies may help to gather intelligence and detect diseases early, and communicate and exchange information electronically worldwide. Some of the technologies brought forward during the <span class="hlt">SARS</span> epidemic may have been primarily motivated by marketing efforts, or were more directed towards reassuring people that "something is being done," ie, fighting an "epidemic of fear." To understand "fear epidemiology" is important because early warning systems monitoring data from a large number of people may not be able to discriminate between a biological epidemic and an epidemic of fear. The need for critical evaluation of all of these technologies is stressed. PMID:12857670</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AdSpR..57.1939A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AdSpR..57.1939A&link_type=ABSTRACT"><span id="translatedtitle">Forest classification using extracted Pol<span class="hlt">SAR</span> features from Compact Polarimetry data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aghabalaei, Amir; Maghsoudi, Yasser; Ebadi, Hamid</p> <p>2016-05-01</p> <p>This study investigates the ability of extracted Polarimetric Synthetic Aperture RADAR (Pol<span class="hlt">SAR</span>) features from Compact Polarimetry (CP) data for forest classification. The CP is a new mode that is recently proposed in Dual Polarimetry (DP) imaging system. It has several important advantages in comparison with Full Polarimetry (FP) mode such as reduction ability in complexity, cost, mass, data <span class="hlt">rate</span> of a <span class="hlt">SAR</span> system. Two strategies are employed for Pol<span class="hlt">SAR</span> feature extraction. In first strategy, the features are extracted using 2 × 2 covariance matrices of CP modes simulated by RADARSAT-2 C-band FP mode. In second strategy, they are extracted using 3 × 3 covariance matrices reconstructed from the CP modes called Pseudo Quad (PQ) modes. In each strategy, the extracted Pol<span class="hlt">SAR</span> features are combined and optimal features are selected by Genetic Algorithm (GA) and then a Support Vector Machine (SVM) classifier is applied. Finally, the results are compared with the FP mode. Results of this study show that the Pol<span class="hlt">SAR</span> features extracted from π / 4 CP mode, as well as combining the Pol<span class="hlt">SAR</span> features extracted from CP or PQ modes provide a better overall accuracy in classification of forest.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3705480','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3705480"><span id="translatedtitle">Ship Detection in <span class="hlt">SAR</span> Image Based on the Alpha-stable Distribution</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Changcheng; Liao, Mingsheng; Li, Xiaofeng</p> <p>2008-01-01</p> <p>This paper describes an improved Constant False Alarm <span class="hlt">Rate</span> (CFAR) ship detection algorithm in spaceborne synthetic aperture radar (<span class="hlt">SAR</span>) image based on Alpha-stable distribution model. Typically, the CFAR algorithm uses the Gaussian distribution model to describe statistical characteristics of a <span class="hlt">SAR</span> image background clutter. However, the Gaussian distribution is only valid for multilook <span class="hlt">SAR</span> images when several radar looks are averaged. As sea clutter in <span class="hlt">SAR</span> images shows spiky or heavy-tailed characteristics, the Gaussian distribution often fails to describe background sea clutter. In this study, we replace the Gaussian distribution with the Alpha-stable distribution, which is widely used in impulsive or spiky signal processing, to describe the background sea clutter in <span class="hlt">SAR</span> images. In our proposed algorithm, an initial step for detecting possible ship targets is employed. Then, similar to the typical two-parameter CFAR algorithm, a local process is applied to the pixel identified as possible target. A RADARSAT-1 image is used to validate this Alpha-stable distribution based algorithm. Meanwhile, known ship location data during the time of RADARSAT-1 <span class="hlt">SAR</span> image acquisition is used to validate ship detection results. Validation results show improvements of the new CFAR algorithm based on the Alpha-stable distribution over the CFAR algorithm based on the Gaussian distribution.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3323313','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3323313"><span id="translatedtitle">Detection of <span class="hlt">SARS</span>-associated Coronavirus in Throat Wash and Saliva in Early Diagnosis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Wei-Kung; Chen, Shey-Ying; Liu, I-Jung; Chen, Yee-Chun; Chen, Hui-Ling; Yang, Chao-Fu; Chen, Pei-Jer; Yeh, Shiou-Hwei; Kao, Chuan-Liang; Huang, Li-Min; Hsueh, Po-Ren; Wang, Jann-Tay; Sheng, Wang-Hwei; Fang, Chi-Tai; Hung, Chien-Ching; Hsieh, Szu-Min; Su, Chan-Ping; Chiang, Wen-Chu; Yang, Jyh-Yuan; Lin, Jih-Hui; Hsieh, Szu-Chia; Hu, Hsien-Ping; Chiang, Yu-Ping; Wang, Jin-Town; Yang, Pan-Chyr</p> <p>2004-01-01</p> <p>The severe acute respiratory syndrome–associated coronavirus (<span class="hlt">SARS</span>-CoV) is thought to be transmitted primarily through dispersal of droplets, but little is known about the load of <span class="hlt">SARS</span>-CoV in oral droplets. We examined oral specimens, including throat wash and saliva, and found large amounts of <span class="hlt">SARS</span>-CoV RNA in both throat wash (9.58 x 102 to 5.93 x 106 copies/mL) and saliva (7.08 x 103 to 6.38 x 108 copies/mL) from all specimens of 17 consecutive probable <span class="hlt">SARS</span> case-patients, supporting the possibility of transmission through oral droplets. Immunofluorescence study showed replication of <span class="hlt">SARS</span>-CoV in the cells derived from throat wash, demonstrating the possibility of developing a convenient antigen detection assay. This finding, with the high detection <span class="hlt">rate</span> a median of 4 days after disease onset and before the development of lung lesions in four patients, suggests that throat wash and saliva should be included in sample collection guidelines for <span class="hlt">SARS</span> diagnosis. PMID:15324540</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8746E..09M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8746E..09M"><span id="translatedtitle">An application of backprojection for video <span class="hlt">SAR</span> image formation exploiting a subaperature circular shift register</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, J.; Bishop, E.; Doerry, A.</p> <p>2013-05-01</p> <p>This paper details a Video <span class="hlt">SAR</span> (Synthetic Aperture Radar) mode that provides a persistent view of a scene centered at the Motion Compensation Point (MCP). The radar platform follows a circular flight path. An objective is to form a sequence of <span class="hlt">SAR</span> images while observing dynamic scene changes at a selectable video frame <span class="hlt">rate</span>. A formulation of backprojection meets this objective. Modified backprojection equations take into account changes in the grazing angle or squint angle that result from non-ideal flight paths. The algorithm forms a new video frame relying upon much of the signal processing performed in prior frames. The method described applies an appropriate azimuth window to each video frame for window sidelobe rejection. A Cardinal Direction Up (CDU) coordinate frame forms images with the top of the image oriented along a given cardinal direction for all video frames. Using this coordinate frame helps characterize a moving target's target response. Generation of synthetic targets with linear motion including both constant velocity and constant acceleration is described. The synthetic target video imagery demonstrates dynamic <span class="hlt">SAR</span> imagery with expected moving target responses. The paper presents 2011 flight data collected by General Atomics Aeronautical Systems, Inc. (GA-ASI) implementing the video <span class="hlt">SAR</span> mode. The flight data demonstrates good video quality showing moving vehicles. The flight imagery demonstrates the real-time capability of the video <span class="hlt">SAR</span> mode. The video <span class="hlt">SAR</span> mode uses a circular shift register of subapertures. The radar employs a Graphics Processing Unit (GPU) in order to implement this algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESASP.731E...4F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESASP.731E...4F"><span id="translatedtitle">Moving from Temporal Coherence to Decorrelation Time of Interferometric Measurements Exploiting ESA's <span class="hlt">SAR</span> Archive</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foumelis, Michael; Mitraka, Zina; Cuccu, Roberto; Desnos, Yves-Louis; Engdahl, Marcus</p> <p>2015-05-01</p> <p>Interferometric coherence can be considered as an expression of temporal decorrelation. It is understood that interferometric coherence decreases with time between <span class="hlt">SAR</span> acquisitions because of changes in surface reflectivity, reducing the quality of <span class="hlt">SAR</span> phase measurements. This is an intrinsic characteristic of the design of <span class="hlt">SAR</span> systems that has a significant contribution at longer time scales. Although in the past there was not sufficient amount of <span class="hlt">SAR</span> data to extract robust statistical metrics for decorrelation, in the present study it is demonstrated that tailored analysis of interferometric coherence exploiting the large <span class="hlt">SAR</span> archive available by the European Space Agency (ESA), enables the accurate quantification of temporal decorrelation. A methodology to translate the observed <span class="hlt">rate</span> of coherence loss into decorrelation times over a volcanic landscape, namely the Santorini volcanic complex is the subject treated in this study. Specifically, a sensitivity analysis was performed on a large data stack of interferometric pairs to quantify at a pixel level the time beyond which the interferometric phase becomes practically unusable due to the effect of decorrelation. Though the dependence of decorrelation on various land cover/use types is already documented the provision of additional information regarding the expected time of decorrelation is of practical use especially when EO data are utilized in operational activities. The performed analysis is viewed within the improved capacity of current and future <span class="hlt">SAR</span> systems, while underlining the necessity for exploitation of archive data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJE...103..609H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJE...103..609H"><span id="translatedtitle">Deceptive jamming for countering UWB-<span class="hlt">SAR</span> based on Doppler frequency phase template of false target</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Xiaodong; Tang, Bin</p> <p>2016-04-01</p> <p>A false target deceptive jamming method for countering ultra-wideband synthetic aperture radar (UWB-<span class="hlt">SAR</span>) is proposed in this paper, which is based on dechirp processing to intercepted UWB-<span class="hlt">SAR</span> signal and inverse dechirp to jamming signal. The jammer quadrature down-converts and dechirps the intercepted UWB-<span class="hlt">SAR</span> signal using a linear frequency modulation (LFM) signal oscillator, which could reduce the bandwidth and sample <span class="hlt">rate</span> of analog-to-digital converter. Then, the jammer utilises the azimuth direction Doppler frequency phase between the false target and the jammer, and backward reflection coefficient template to modulate the phase of the intercepted UWB-<span class="hlt">SAR</span> signal, and then delayed the modulated phase and also modulated the range direction Doppler frequency phase to the that. Finally, the jammer uses LFM signal oscillator to up-convert the narrowband jamming signal in order to recover the bandwidth of the signal. Parameter errors analysis and simulation results have shown that the detected parameters and motion characteristic errors reduce the resolution and offset the expected position of the false target, but it still could obtain an expected false target image. Theoretical analysis and simulation results indicated that the jamming signal proposed in this paper could produce a false target in the UWB-<span class="hlt">SAR</span> image, which provide a feasible method for countering UWB-<span class="hlt">SAR</span> in real time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005SPIE.5788....1L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005SPIE.5788....1L&link_type=ABSTRACT"><span id="translatedtitle">History of <span class="hlt">SAR</span> at Lockheed Martin (previously Goodyear Aerospace)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lasswell, Stephen W.</p> <p>2005-05-01</p> <p>Synthetic Aperture Radar (<span class="hlt">SAR</span>) was invented by Carl Wiley at Goodyear Aircraft Company in Goodyear, Arizona, in 1951. From that time forward, as the company became Goodyear Aerospace Corporation, Loral Corporation, and finally Lockheed Martin Corporation, the Arizona employees past and present played a long and storied role in numerous <span class="hlt">SAR</span> firsts. These include the original <span class="hlt">SAR</span> patent (known as Simultaneous Doppler Buildup), the first demonstration <span class="hlt">SAR</span> and flight test, the first operational <span class="hlt">SAR</span> system, the first operational <span class="hlt">SAR</span> data link, the first 5-foot resolution operational <span class="hlt">SAR</span> system, the first 1-foot resolution <span class="hlt">SAR</span> system, and the first large scale <span class="hlt">SAR</span> digital processor. The company has installed and flown over five hundred <span class="hlt">SAR</span> systems on more than thirty different types of aircraft for numerous countries throughout the world. The company designed and produced all of the evolving high performance <span class="hlt">SAR</span> systems for the U. S. Air Force SR-71 "Blackbird" spy plane throughout its entire operational history, spanning some twenty-nine years. Recent <span class="hlt">SAR</span> accomplishments include long-range standoff high performance <span class="hlt">SAR</span> systems, smaller high resolution podded <span class="hlt">SAR</span> systems for fighter aircraft, and foliage penetration (FOPEN) <span class="hlt">SAR</span>. The company is currently developing the high performance <span class="hlt">SAR</span>/MTI (Moving Target Indication) radar for the Army Aerial Common Sensor (ACS) system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7699E..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7699E..06G"><span id="translatedtitle"><span class="hlt">SAR</span> image formation toolbox for MATLAB</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorham, LeRoy A.; Moore, Linda J.</p> <p>2010-04-01</p> <p>While many synthetic aperture radar (<span class="hlt">SAR</span>) image formation techniques exist, two of the most intuitive methods for implementation by <span class="hlt">SAR</span> novices are the matched filter and backprojection algorithms. The matched filter and (non-optimized) backprojection algorithms are undeniably computationally complex. However, the backprojection algorithm may be successfully employed for many <span class="hlt">SAR</span> research endeavors not involving considerably large data sets and not requiring time-critical image formation. Execution of both image reconstruction algorithms in MATLAB is explicitly addressed. In particular, a manipulation of the backprojection imaging equations is supplied to show how common MATLAB functions, ifft and interp1, may be used for straight-forward <span class="hlt">SAR</span> image formation. In addition, limits for scene size and pixel spacing are derived to aid in the selection of an appropriate imaging grid to avoid aliasing. Example <span class="hlt">SAR</span> images generated though use of the backprojection algorithm are provided given four publicly available <span class="hlt">SAR</span> datasets. Finally, MATLAB code for <span class="hlt">SAR</span> image reconstruction using the matched filter and backprojection algorithms is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910031188&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsars','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910031188&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsars"><span id="translatedtitle">The Alaska <span class="hlt">SAR</span> processor - Operations and control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carande, Richard E.</p> <p>1989-01-01</p> <p>The Alaska <span class="hlt">SAR</span> (synthetic-aperture radar) Facility (ASF) will be capable of receiving, processing, archiving, and producing a variety of <span class="hlt">SAR</span> image products from three satellite-borne <span class="hlt">SARs</span>: E-ERS-1 (ESA), J-ERS-1 (NASDA) and Radarsat (Canada). Crucial to the success of the ASF is the Alaska <span class="hlt">SAR</span> processor (ASP), which will be capable of processing over 200 100-km x 100-km (Seasat-like) frames per day from the raw <span class="hlt">SAR</span> data, at a ground resolution of about 30 m x 30 m. The processed imagery is of high geometric and radiometric accuracy, and is geolocated to within 500 m. Special-purpose hardware has been designed to execute a <span class="hlt">SAR</span> processing algorithm to achieve this performance. This hardware is currently undergoing acceptance testing for delivery to the University of Alaska. Particular attention has been devoted to making the operations semi-automated and to providing a friendly operator interface via a computer workstation. The operations and control of the Alaska <span class="hlt">SAR</span> processor are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8714E..0UE','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8714E..0UE"><span id="translatedtitle"><span class="hlt">SAR</span> and LIDAR fusion: experiments and applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edwards, Matthew C.; Zaugg, Evan C.; Bradley, Joshua P.; Bowden, Ryan D.</p> <p>2013-05-01</p> <p>In recent years ARTEMIS, Inc. has developed a series of compact, versatile Synthetic Aperture Radar (<span class="hlt">SAR</span>) systems which have been operated on a variety of small manned and unmanned aircraft. The multi-frequency-band Slim<span class="hlt">SAR</span> has demonstrated a variety of capabilities including maritime and littoral target detection, ground moving target indication, polarimetry, interferometry, change detection, and foliage penetration. ARTEMIS also continues to build upon the radar's capabilities through fusion with other sensors, such as electro-optical and infrared camera gimbals and light detection and ranging (LIDAR) devices. In this paper we focus on experiments and applications employing <span class="hlt">SAR</span> and LIDAR fusion. LIDAR is similar to radar in that it transmits a signal which, after being reflected or scattered by a target area, is recorded by the sensor. The differences are that a LIDAR uses a laser as a transmitter and optical sensors as a receiver, and the wavelengths used exhibit a very different scattering phenomenology than the microwaves used in radar, making <span class="hlt">SAR</span> and LIDAR good complementary technologies. LIDAR is used in many applications including agriculture, archeology, geo-science, and surveying. Some typical data products include digital elevation maps of a target area and features and shapes extracted from the data. A set of experiments conducted to demonstrate the fusion of <span class="hlt">SAR</span> and LIDAR data include a LIDAR DEM used in accurately processing the <span class="hlt">SAR</span> data of a high relief area (mountainous, urban). Also, feature extraction is used in improving geolocation accuracy of the <span class="hlt">SAR</span> and LIDAR data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21202526','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21202526"><span id="translatedtitle">Next generation <span class="hlt">SAR</span> demonstration on space station</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Edelstein, Wendy; Kim, Yunjin; Freeman, Anthony; Jordan, Rolando</p> <p>1999-01-22</p> <p>This paper describes the next generation synthetic aperture radar (<span class="hlt">SAR</span>) that enables future low cost space-borne radar missions. In order to realize these missions, we propose to use an inflatable, membrane, microstrip antenna that is particularly suitable for low frequency science radar missions. In order to mitigate risks associated with this revolutionary technology, the space station demonstration will be very useful to test the long-term survivability of the proposed antenna. This experiment will demonstrate several critical technology challenges associated with space-inflatable technologies. Among these include space-rigidization of inflatable structures, controlled inflation deployment, flatness and uniform separation of thin-film membranes and RF performance of membrane microstrip antennas. This mission will also verify the in-space performance of lightweight, high performance advanced <span class="hlt">SAR</span> electronics. Characteristics of this <span class="hlt">SAR</span> instrument include a capability for high resolution polarimetric imaging. The mission will acquire high quality scientific data using this advanced <span class="hlt">SAR</span> to demonstrate the utility of these advanced technologies. We will present an inflatable L-band <span class="hlt">SAR</span> concept for commercial and science applications and a P-band design concept to validate the Biomass <span class="hlt">SAR</span> mission concept. The ionospheric effects on P-band <span class="hlt">SAR</span> images will also be examined using the acquired data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=319707','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=319707"><span id="translatedtitle">Dynamic mechanical analysis and high strain-<span class="hlt">rate</span> energy <span class="hlt">absorption</span> characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>The dynamic mechanical behavior and energy <span class="hlt">absorption</span> characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20130003259&hterms=digital+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddigital%2Bcopyright','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20130003259&hterms=digital+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddigital%2Bcopyright"><span id="translatedtitle">First Results from an Airborne Ka-band <span class="hlt">SAR</span> Using Sweep<span class="hlt">SAR</span> and Digital Beamforming</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sadowy, Gregory; Ghaemi, Hirad; Hensley, Scott</p> <p>2012-01-01</p> <p>NASA/JPL has developed Sweep<span class="hlt">SAR</span> technique that breaks typical Synthetic Aperture Radar (<span class="hlt">SAR</span>) trade space using time-dependent multi-beam DBF on receive. Developing Sweep<span class="hlt">SAR</span> implementation using array-fed reflector for proposed DESDynI Earth Radar Mission concept. Performed first-of-a-kind airborne demonstration of the Sweep<span class="hlt">SAR</span> concept at Ka-band (35.6 GHz). Validated calibration and antenna pattern data sufficient for beam forming in elevation. (1) Provides validation evidence that the proposed Deformation Ecosystem Structure Dynamics of Ice (DESDynI) <span class="hlt">SAR</span> architecture is sound. (2) Functions well even with large variations in receiver gain / phase. Future plans include using prototype DESDynI <span class="hlt">SAR</span> digital flight hardware to do the beam forming in real-time onboard the aircraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890052246&hterms=positioning+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpositioning%2Bimage','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890052246&hterms=positioning+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpositioning%2Bimage"><span id="translatedtitle">Geometric accuracy in airborne <span class="hlt">SAR</span> images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blacknell, D.; Quegan, S.; Ward, I. A.; Freeman, A.; Finley, I. P.</p> <p>1989-01-01</p> <p>Uncorrected across-track motions of a synthetic aperture radar (<span class="hlt">SAR</span>) platform can cause both a severe loss of azimuthal positioning accuracy in, and defocusing of, the resultant <span class="hlt">SAR</span> image. It is shown how the results of an autofocus procedure can be incorporated in the azimuth processing to produce a fully focused image that is geometrically accurate in azimuth. Range positioning accuracy is also discussed, leading to a comprehensive treatment of all aspects of geometric accuracy. The system considered is an X-band <span class="hlt">SAR</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996SPIE.2747...61K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996SPIE.2747...61K"><span id="translatedtitle">Design considerations of Geo<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Yunjin; Hensley, Scott; Veilleux, Louise; Edelstein, W.; Lou, Yun-Ling; Burken, A.; Skotnicky, W. F.; Sato, T.; Brown, W.</p> <p>1996-06-01</p> <p>The primary purpose of Geo<span class="hlt">SAR</span> is to demonstrate the feasibility of interferometric topographic mapping through foliage penetration. Geo<span class="hlt">SAR</span> should become a commercially viable instrument after the feasibility demonstration. To satisfy both requirements, we have designed a dual frequency (UHF- and X-band) interferometric radar. For foliage penetration, a lower frequency (UHF) radar is used. To obtain better height accuracy for low backscatter areas, we proposed a high frequency (X-band) interferometric system. In this paper, we present a possible Geo<span class="hlt">SAR</span> system configuration and associated performance estimation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011443','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011443"><span id="translatedtitle">Primary studies of Chinese spaceborne <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, Zhen-Song; Wu, Guo-Xiang; Guo, Hua-Dong; Wei, Zhong-Quan; Zhu, Min-Hui</p> <p>1993-01-01</p> <p>The primary studies on spaceborne synthetic aperture radar (<span class="hlt">SAR</span>) in China are discussed. The <span class="hlt">SAR</span> will be launched aboard a Chinese satellite and operated at L-band with HH polarization. The purpose of the mission in consideration is dedicated to resources and environment uses, especially to natural disaster monitoring. The ground resolution is designed as 25 m x 25 m for detailed mode and 100 m x 100 m for wide scan-<span class="hlt">SAR</span> mode. The off-nadir angle can be varied from 20 to 40 deg. The key system concepts are introduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860001148','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860001148"><span id="translatedtitle">NASA/JPL Aircraft <span class="hlt">SAR</span> Workshop Proceedings</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Donovan, N. (Editor); Evans, D. L. (Editor); Held, D. N. (Editor)</p> <p>1985-01-01</p> <p>Speaker-supplied summaries of the talks given at the NASA/JPL Aircraft <span class="hlt">SAR</span> Workshop on February 4 and 5, 1985, are provided. These talks dealt mostly with composite quadpolarization imagery from a geologic or ecologic prespective. An overview and summary of the system characteristics of the L-band synthetic aperture radar (<span class="hlt">SAR</span>) flown on the NASA CV-990 aircraft are included as supplementary information. Other topics ranging from phase imagery and interferometric techniques classifications of specific areas, and the potentials and limitations of <span class="hlt">SAR</span> imagery in various applications are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930000799&hterms=Segmentation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSegmentation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930000799&hterms=Segmentation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSegmentation"><span id="translatedtitle">Segmentation Of Multifrequency, Multilook <span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rignot, Eric J.; Kwok, Ronald; Chellappa, Rama</p> <p>1993-01-01</p> <p>Segmentation of multifrequency, multilook synthetic-aperture radar (<span class="hlt">SAR</span>) image intensity data into regions, within each of which backscattering characteristics of target scene considered homogeneous, enhanced by use of two statistical models. One represents statistics of multifrequency, multilook speckled intensities of <span class="hlt">SAR</span> picture elements; other represents statistics of labels applied to regions into which picture elements grouped. Each region represents different type of terrain, terrain cover, or other surface; e.g., forest, agricultural land, sea ice, or water. Segmentation of image into regions of neighboring picture elements accomplished by method similar to that described in "Algorithms For Segmentation Of Complex-Amplitude <span class="hlt">SAR</span> Data" (NPO-18524).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.T44B..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.T44B..02L"><span id="translatedtitle">Cascades of In<span class="hlt">SAR</span> in the Cascades - outlook for the use of In<span class="hlt">SAR</span> and space-based imaging catalogues in a Subduction Zone Observatory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lohman, R. B.</p> <p>2015-12-01</p> <p>Interferometric synthetic aperture radar (In<span class="hlt">SAR</span>) has long demonstrated its utility to studies of subduction zone earthquakes, crustal events and volcanic processes, particularly in regions with very good temporal data coverage (e.g., Japan), or arid regions where the timescale of surface change is long compared to the repeat time of the available <span class="hlt">SAR</span> imagery (e.g., portions of South America). Recently launched and future <span class="hlt">SAR</span> missions with open data access will increase the temporal sampling <span class="hlt">rates</span> further over many areas of the globe, resulting in a new ability to lower the detection threshold for earthquakes and, potentially, interseismic motion and transients associated with subduction zone settings. Here we describe some of the anticipated detection abilities for events ranging from earthquakes and slow slip along the subduction zone interface up to landslides, and examine the variations in land use around the circum-Pacific and how that and its changes over time will affect the use of In<span class="hlt">SAR</span>. We will show the results of an effort to combine Landsat and other optical imagery with <span class="hlt">SAR</span> data catalogues in the Pacific Northwest to improve the characterization of ground deformation signals, including the identification of "spurious" signals that are not related to true ground deformation. We also describe prospects for working with other communities that are interested in variations in soil moisture and vegetation structure over the same terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPD....47.1102D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPD....47.1102D&link_type=ABSTRACT"><span id="translatedtitle">The Compound and Homologous Eruptions from the <span class="hlt">SAR</span> 11429</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dhakal, Suman Kumar; Zhang, Jie</p> <p>2016-05-01</p> <p>Super Active Regions (<span class="hlt">SARs</span>) are ARs which shows extremely high <span class="hlt">rate</span> of solar eruptions. NOAA AR 11429 was a <span class="hlt">SAR</span> which produced 47 C-Class, 15 M-Class and 3 X-Class flares and 8 CMEs during its passage from the front disk of the Sun. This <span class="hlt">SAR</span> had anti-Hale and delta-spot magnetic configuration and many sub-regions of magnetic flux emergence. With the aid of multi-wavelength observations of the Solar Dynamics Observatory (SDO), the Solar Terrestrial Relations Observatory (STEREO) and nonlinear force-free model for the magnetic field in the solar corona, we found the existence of many magnetic flux structures (flux bundles) in the corona of the AR. The energy released by these co-existing flux bundles within short time, resulted in compound erutpions from the AR on March 9 and 10, 2012. In the period of 38 hours, after the CME eruption on March 9, the continuous shearing and cancellation and new magnetic flux emergence resulted in another CME on March 10. Both of the events showed the compound nature and the similarity of the foot-points and EUV dimming made these eruptions homologous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AtmEn..38.3879A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AtmEn..38.3879A"><span id="translatedtitle">Monitoring of viable airborne <span class="hlt">SARS</span> virus in ambient air</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agranovski, Igor E.; Safatov, Alexander S.; Pyankov, Oleg V.; Sergeev, Alexander N.; Agafonov, Alexander P.; Ignatiev, Georgy M.; Ryabchikova, Elena I.; Borodulin, Alexander I.; Sergeev, Artemii A.; Doerr, Hans W.; Rabenau, Holger F.; Agranovski, Victoria</p> <p></p> <p>Due to recent <span class="hlt">SARS</span> related issues (Science 300 (5624) 1394; Nature 423 (2003) 240; Science 300 (5627) 1966), the development of reliable airborne virus monitoring procedures has become galvanized by an exceptional sense of urgency and is presently in a high demand (In: Cox, C.S., Wathers, C.M. (Eds.), Bioaerosols Handbook, Lewis Publishers, Boca Raton, FL, 1995, pp. 247-267). Based on engineering control method (Aerosol Science and Technology 31 (1999) 249; 35 (2001) 852), which was previously applied to the removal of particles from gas carriers, a new personal bioaerosol sampler has been developed. Contaminated air is bubbled through porous medium submerged into liquid and subsequently split into multitude of very small bubbles. The particulates are scavenged by these bubbles, and, thus, effectively removed. The current study explores its feasibility for monitoring of viable airborne <span class="hlt">SARS</span> virus. It was found that the natural decay of such virus in the collection fluid was around 0.75 and 1.76 lg during 2 and 4 h of continuous operation, respectively. Theoretical microbial recovery <span class="hlt">rates</span> of higher than 55 and 19% were calculated for 1 and 2 h of operation, respectively. Thus, the new sampling method of direct non-violent collection of viable airborne <span class="hlt">SARS</span> virus into the appropriate liquid environment was found suitable for monitoring of such stress sensitive virus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPArXL74...13D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPArXL74...13D&link_type=ABSTRACT"><span id="translatedtitle">Similarity measures of full polarimetric <span class="hlt">SAR</span> images fusion for improved <span class="hlt">SAR</span> image matching</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, H.</p> <p>2015-06-01</p> <p>China's first airborne <span class="hlt">SAR</span> mapping system (CASMSAR) developed by Chinese Academy of Surveying and Mapping can acquire high-resolution and full polarimetric (HH, HV, VH and VV) Synthetic aperture radar (<span class="hlt">SAR</span>) data. It has the ability to acquire X-band full polarimetric <span class="hlt">SAR</span> data at a resolution of 0.5m. However, the existence of speckles which is inherent in <span class="hlt">SAR</span> imagery affects visual interpretation and image processing badly, and challenges the assumption that conjugate points appear similar to each other in matching processing. In addition, researches show that speckles are multiplicative speckles, and most similarity measures of <span class="hlt">SAR</span> image matching are sensitive to them. Thus, matching outcomes of <span class="hlt">SAR</span> images acquired by most similarity measures are not reliable and with bad accuracy. Meanwhile, every polarimetric <span class="hlt">SAR</span> image has different backscattering information of objects from each other and four polarimetric <span class="hlt">SAR</span> data contain most basic and a large amount of redundancy information to improve matching. Therefore, we introduced logarithmically transformation and a stereo matching similarity measure into airborne full polarimetric <span class="hlt">SAR</span> imagery. Firstly, in order to transform the multiplicative speckles into additivity ones and weaken speckles' influence on similarity measure, logarithmically transformation have to be taken to all images. Secondly, to prevent performance degradation of similarity measure caused by speckles, measure must be free or insensitive of additivity speckles. Thus, we introduced a stereo matching similarity measure, called Normalized Cross-Correlation (NCC), into full polarimetric <span class="hlt">SAR</span> image matching. Thirdly, to take advantage of multi-polarimetric data and preserve the best similarity measure value, four measure values calculated between left and right single polarimetric <span class="hlt">SAR</span> images are fused as final measure value for matching. The method was tested for matching under CASMSAR data. The results showed that the method delivered an effective</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830009652','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830009652"><span id="translatedtitle">SEASAT <span class="hlt">SAR</span> performance evaluation study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1982-01-01</p> <p>The performance of the SEASAT synthetic aperture radar (<span class="hlt">SAR</span>) sensor was evaluated using data processed by the MDA digital processor. Two particular aspects are considered the location accuracy of image data, and the calibration of the measured backscatter amplitude of a set of corner reflectors. The image location accuracy was assessed by selecting identifiable targets in several scenes, converting their image location to UTM coordinates, and comparing the results to map sheets. The error standard deviation is measured to be approximately 30 meters. The amplitude was calibrated by measuring the responses of the Goldstone corner reflector array and comparing the results to theoretical values. A linear regression of the measured against theoretical values results in a slope of 0.954 with a correlation coefficient of 0.970.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.G51A..08D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.G51A..08D"><span id="translatedtitle">Coastal and Wetlands Applications for an In<span class="hlt">SAR</span> Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dixon, T.; Amelung, F.; Gourmelen, N.; Kim, S.; Osmanoglu, B.; Wdowinski, S.</p> <p>2006-12-01</p> <p>Interferometric Synthetic Aperture Radar (In<span class="hlt">SAR</span>) has found wide application in the study of Earth surface change, including earthquake and volcano deformation, motion of glaciers and ice sheets, and ground subsidence due to fluid extraction. In the last few years, In<span class="hlt">SAR</span> may have significant application in studies of wetlands, coastal regions, and related environmental problems. These are becoming increasingly important as global warming contributes to sea level rise, with consequent modification or loss of coastal habitat, and increased storm frequency/intensity, with consequent increased hazard to coastal communities. Most of these applications would benefit from increased data availability and spatial resolution. A common problem for many In<span class="hlt">SAR</span> studies in these areas is the influence of spatially and temporally variable tropospheric water vapor. Multiple interferograms can be used to average down tropospheric noise, or selectively edit image pairs where tropospheric noise is high. Alternately, the Permanent Scatterer (PSIn<span class="hlt">SAR</span>) technique can produce an average surface change <span class="hlt">rate</span> over several months or years for coastal land applications where the assumption of steady state deformation is reasonable (e.g., some land subsidence applications). This technique also effectively identifies tropospheric noise. Common to both approaches is the need for large numbers of images, closely spaced in time. Wetland water levels also change on short time scales (days to weeks) implying the need for frequent coverage. Hence, such applications benefit from mission scenarios emphasizing repeat times shorter than 7 days. Assuming global coverage is desirable, the requirement for rapid re-survey suggests that multi-satellite constellations should be considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8562E..10G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8562E..10G"><span id="translatedtitle">A low-power <span class="hlt">SAR</span> ADC for IRFPA ROIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Lei; Ding, Ruijun; Zhou, Jie; Wang, Pan; Chen, Guoqiang</p> <p>2012-12-01</p> <p>This paper presents a low power ADC for the 512*512 infrared focal plane arrays (IRFPA) readout integrated circuit(ROIC). The major structure, the working mode and the simulation result of the readout integrated circuit are shown in this paper. The power supply voltage of 0.35μm standard CMOS process is 3.3V in this design, and then the output range of the Direct Injection (DI) input circuit is reached 2V. Successive-approximation-register (<span class="hlt">SAR</span>) ADC architecture is used in this readout integrated circuit. And each ADC is shared by one column of the IRFPA. This <span class="hlt">SAR</span> ADC is made up of a 13-bit digital-analog converter (DAC), a high resolution comparator, and a digital control circuit. The most important part is the voltage-scaling and charge-scaling charge redistribution DAC. In this DAC, charge scaling with a capacitor ladder to determine the least significant bits is combined with voltage scaling with a resister ladder to determine the most significant bits. The comparator uses three-stage operational amplifier structure to get a 77dB differential gain. The Common-Mode input rang of the comparator is 1V to 3V, and minimum resolvable voltage difference is 0.3mV. This <span class="hlt">SAR</span> ADC has some advantages, especially in low power and high speed. The simulation result shows that the resolution of the ADC is 12 bit and the conversion time of the ADC is 6.5μs, while the power of each ADC is as low as 300μW. Finally, this <span class="hlt">SAR</span> ADC can satisfy the request of 512*512 IRFPAs ROIC with a 100Hz frame <span class="hlt">rate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPArXL74..231Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPArXL74..231Z"><span id="translatedtitle">Combined DEM Extration Method from Stereo<span class="hlt">SAR</span> and In<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Z.; Zhang, J. X.; Duan, M. Y.; Huang, G. M.; Yang, S. C.</p> <p>2015-06-01</p> <p>A pair of <span class="hlt">SAR</span> images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo <span class="hlt">SAR</span> and interferometric <span class="hlt">SAR</span>. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, Stereo<span class="hlt">SAR</span> and In<span class="hlt">SAR</span> combined adjustment model are constructed, and unify DEM extraction from In<span class="hlt">SAR</span> and Stereo<span class="hlt">SAR</span> into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of <span class="hlt">SAR</span> images 1,2 meet the required conditions for In<span class="hlt">SAR</span> technology, while the other pair of <span class="hlt">SAR</span> images 3,4 can form stereo image pairs. The phase model is based on In<span class="hlt">SAR</span> rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in In<span class="hlt">SAR</span> processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn't require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne In<span class="hlt">SAR</span> and Stereo<span class="hlt">SAR</span> data and compared with In<span class="hlt">SAR</span> and Stereo<span class="hlt">SAR</span> methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvL.111n4101A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvL.111n4101A"><span id="translatedtitle">Chaotic Systems with <span class="hlt">Absorption</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Altmann, Eduardo G.; Portela, Jefferson S. E.; Tél, Tamás</p> <p>2013-10-01</p> <p>Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe <span class="hlt">absorption</span> in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape <span class="hlt">rate</span> κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions Dq obtained without taking <span class="hlt">absorption</span> and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D1 in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection <span class="hlt">rate</span>. Simulations in the cardioid billiard confirm these results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20808028','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20808028"><span id="translatedtitle">The influence of the reflective environment on the <span class="hlt">absorption</span> of a human male exposed to representative base station antennas from 300 MHz to 5 GHz.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vermeeren, G; Gosselin, M C; Kühn, S; Kellerman, V; Hadjem, A; Gati, A; Joseph, W; Wiart, J; Meyer, F; Kuster, N; Martens, L</p> <p>2010-09-21</p> <p>The environment is an important parameter when evaluating the exposure to radio-frequency electromagnetic fields. This study investigates numerically the variation on the whole-body and peak spatially averaged-specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) in the heterogeneous virtual family male placed in front of a base station antenna in a reflective environment. The <span class="hlt">SAR</span> values in a reflective environment are also compared to the values obtained when no environment is present (free space). The virtual family male has been placed at four distances (30 cm, 1 m, 3 m and 10 m) in front of six base station antennas (operating at 300 MHz, 450 MHz, 900 MHz, 2.1 GHz, 3.5 GHz and 5.0 GHz, respectively) and in three reflective environments (a perfectly conducting wall, a perfectly conducting ground and a perfectly conducting ground + wall). A total of 72 configurations are examined. The <span class="hlt">absorption</span> in the heterogeneous body model is determined using the 3D electromagnetic (EM) finite-difference time-domain (FDTD) solver Semcad-X. For the larger simulations, requirements in terms of computer resources are reduced by using a generalized Huygens' box approach. It has been observed that the ratio of the <span class="hlt">SAR</span> in the virtual family male in a reflective environment and the <span class="hlt">SAR</span> in the virtual family male in the free-space environment ranged from -8.7 dB up to 8.0 dB. A worst-case reflective environment could not be determined. ICNIRP reference levels not always showed to be compliant with the basic restrictions. PMID:20808028</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012TRACE..15..381K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012TRACE..15..381K"><span id="translatedtitle">Experimental Analysis of the Effects of Vapor Flow Characteristics on Falling Film <span class="hlt">Absorption</span> <span class="hlt">Rate</span> in NH3-H2O Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kang, Yong Tae; Fujita, Yasushi; Akisawa, Atsushi; Kashiwagi, Takao</p> <p></p> <p>In this paper, experimental analysis was performed for ammonia-water falling film <span class="hlt">absorption</span> process in a plate heat exchanger with enhanced surfaces such as offset strip fin. This paper examined the effect of vapor flow characteristics, inlet subcooling of the liquid flow and inlet concentration difference on heat and mass transfer performance. The inlet liquid concentration was kept constant at 0% while the inlet vapor concentration was varied from70. 36 to 77.31% It was found that before <span class="hlt">absorption</span> started there was rectification process at the top of the test section by the inlet subcooling effect. Water desorption phenomenon was found near the bottom of test section. The lower inlet liquid temperature, the higher Nusselt and Sherwood numbers were obtained. NusseIt and Sherwood correlations were developed as functions of vapor Reynolds number ReV, inlet subcooling and inlet concentration difference with ±10% and ±5% error bands, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3270869','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3270869"><span id="translatedtitle">Statistical Modeling of <span class="hlt">SAR</span> Images: A Survey</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Gui</p> <p>2010-01-01</p> <p>Statistical modeling is essential to <span class="hlt">SAR</span> (Synthetic Aperture Radar) image interpretation. It aims to describe <span class="hlt">SAR</span> images through statistical methods and reveal the characteristics of these images. Moreover, statistical modeling can provide a technical support for a comprehensive understanding of terrain scattering mechanism, which helps to develop algorithms for effective image interpretation and creditable image simulation. Numerous statistical models have been developed to describe <span class="hlt">SAR</span> image data, and the purpose of this paper is to categorize and evaluate these models. We first summarize the development history and the current researching state of statistical modeling, then different <span class="hlt">SAR</span> image models developed from the product model are mainly discussed in detail. Relevant issues are also discussed. Several promising directions for future research are concluded at last. PMID:22315568</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9461E..0PG&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9461E..0PG&link_type=ABSTRACT"><span id="translatedtitle">An algorithm for segmenting polarimetric <span class="hlt">SAR</span> imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geaga, Jorge V.</p> <p>2015-05-01</p> <p>We have developed an algorithm for segmenting fully polarimetric single look Terra<span class="hlt">SAR</span>-X, multilook SIR-C and 7 band Landsat 5 imagery using neural nets. The algorithm uses a feedforward neural net with one hidden layer to segment different surface classes. The weights are refined through an iterative filtering process characteristic of a relaxation process. Features selected from studies of fully polarimetric complex single look Terra<span class="hlt">SAR</span>-X data and multilook SIR-C data are used as input to the net. The seven bands from Landsat 5 data are used as input for the Landsat neural net. The Cloude-Pottier incoherent decomposition is used to investigate the physical basis of the polarimetric <span class="hlt">SAR</span> data segmentation. The segmentation of a SIR-C ocean surface scene into four classes is presented. This segmentation algorithm could be a very useful tool for investigating complex polarimetric <span class="hlt">SAR</span> phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160001388','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160001388"><span id="translatedtitle">Polarimetric <span class="hlt">SAR</span> Interferometry Evaluation in Mangroves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, Seung-Kuk; Fatoyinbo,Temilola; Osmanoglu, Batuhan; Sun, Guoqing</p> <p>2014-01-01</p> <p>TanDEM-X (TDX) enables to generate an interferometric coherence without temporal decorrelation effect that is the most critical factor for a successful Pol-In<span class="hlt">SAR</span> inversion, as have recently been used for forest parameter retrieval. This paper presents mangrove forest height estimation only using single-pass/single-baseline/dual-polarization TDX data by means of new dual-Pol-In<span class="hlt">SAR</span> inversion technique. To overcome a lack of one polarization in a conventional Pol- In<span class="hlt">SAR</span> inversion (i.e. an underdetermined problem), the ground phase in the Pol-In<span class="hlt">SAR</span> model is directly estimated from TDX interferograms assuming flat underlying topography in mangrove forest. The inversion result is validated against lidar measurement data (NASA's G-LiHT data).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880033810&hterms=Product+concept&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DProduct%2Bconcept','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880033810&hterms=Product+concept&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DProduct%2Bconcept"><span id="translatedtitle">Image based <span class="hlt">SAR</span> product simulation for analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Domik, G.; Leberl, F.</p> <p>1987-01-01</p> <p><span class="hlt">SAR</span> product simulation serves to predict <span class="hlt">SAR</span> image gray values for various flight paths. Input typically consists of a digital elevation model and backscatter curves. A new method is described of product simulation that employs also a real <span class="hlt">SAR</span> input image for image simulation. This can be denoted as 'image-based simulation'. Different methods to perform this <span class="hlt">SAR</span> prediction are presented and advantages and disadvantages discussed. Ascending and descending orbit images from NASA's SIR-B experiment were used for verification of the concept: input images from ascending orbits were converted into images from a descending orbit; the results are compared to the available real imagery to verify that the prediction technique produces meaningful image data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840019209','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840019209"><span id="translatedtitle">Tracking ocean wave spectrum from <span class="hlt">SAR</span> images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldfinger, A. D.; Beal, R. C.; Monaldo, F. M.; Tilley, D. G.</p> <p>1984-01-01</p> <p>An end to end algorithm for recovery of ocean wave spectral peaks from Synthetic Aperture Radar (<span class="hlt">SAR</span>) images is described. Current approaches allow precisions of 1 percent in wave number, and 0.6 deg in direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790005271','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790005271"><span id="translatedtitle"><span class="hlt">SAR</span>/LANDSAT image registration study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Murphrey, S. W. (Principal Investigator)</p> <p>1978-01-01</p> <p>The author has identified the following significant results. Temporal registration of synthetic aperture radar data with LANDSAT-MSS data is both feasible (from a technical standpoint) and useful (from an information-content viewpoint). The greatest difficulty in registering aircraft <span class="hlt">SAR</span> data to corrected LANDSAT-MSS data is control-point location. The differences in <span class="hlt">SAR</span> and MSS data impact the selection of features that will serve as a good control points. The <span class="hlt">SAR</span> and MSS data are unsuitable for automatic computer correlation of digital control-point data. The gray-level data can not be compared by the computer because of the different response characteristics of the MSS and <span class="hlt">SAR</span> images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ESASP.709E..39M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ESASP.709E..39M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">SAR</span> Polarimetry for Oil at Sea Observation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Migliaccio, M.; Nunziata, F.</p> <p>2013-03-01</p> <p>Synthetic aperture radar (<span class="hlt">SAR</span>) oil slick observation is a topic of great applicative relevance which has been physically recast by a set of new polarimetric approaches that, exploiting the departure from Bragg scattering, allow observing oil at sea in a very robust and effective way. In this study, these polarimetric approaches are reviewed and their performances are discussed with respect to some thought experiments undertaken on quad-pol full-resolution L- and C-band <span class="hlt">SAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15551530','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15551530"><span id="translatedtitle"><span class="hlt">SAR</span> calculations in an anatomically realistic model of the head for mobile communication transceivers at 900 MHz and 1.8 GHz.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dimbylow, P J; Mann, S M</p> <p>1994-10-01</p> <p>A new mathematical model of the head has been constructed from a set of serial MRI slices from one subject. Finite-difference time-domain (FDTD) calculations of the specific energy <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) have been performed on this model with a 2 mm resolution for a generic mobile communication transceiver represented by a quarter-wavelength monopole on a metal box. The antenna was mounted either at the centre or corner of the top face of the box. The frequencies considered were 900 MHz and 1.8 GHz. Three irradiation geometries were considered, a vertical handset in front of the eye and vertical and horizontal orientations at the side of the ear. The effect of a hand grasping the handset was considered. The head model was scaled to represent the head of an infant and a subset of calculations was performed to verify that the <span class="hlt">SAR</span> deposited in the infant head did not exceed that in the adult. Results are also presented for a half-wavelength dipole. The maximum <span class="hlt">SAR</span> values produced by the generic transceiver for the horizontal orientation at the side of the head which is the most typical position, averaged over 10 g of tissue at 900 MHz and 1.8 GHz, are 2.1 and 3.0 W kg(-1) per W of radiated power. The corresponding values over 1 g of tissue are 2.3 and 4.8 W kg(-1) per W at 900 MHz and 1.8 GHz. However, if one were to consider all possible operational conditions, the placement of the transceiver in front of the eye will give 3.1 and 4.6 W kg(-1) per W averaged over 10 g of tissue and 4.7 and 7.7 W kg(-1) per W over 1 g of tissue at 900 MHz and 1.8 GHz, respectively. PMID:15551530</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdRS....6..319E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdRS....6..319E"><span id="translatedtitle">Influence of GSM900 electromagnetic fields on the metabolic <span class="hlt">rate</span> in rodents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El Ouardi, A.; Streckert, J.; Lerchl, A.; Schwarzpaul, K.; Hansen, V.</p> <p>2008-05-01</p> <p>The development of exposure devices for investigating possible effects of mobile communication systems to non-restrained animals aims at a homogenous field distribution in the area the animals occupy. In the presented 900 MHz exposure device a quite good field homogeneity of 5% (including the standing wave contribution due to internal reflections) is reached in the cage region mainly by flattening the transverse field. For the standard waveguide (WR1150) without dielectric sheets this value reads 14%. The desired maximal whole body specific <span class="hlt">absorption</span> <span class="hlt">rate</span> (<span class="hlt">SAR</span>) of 4 W/kg in the Djungarian hamster model is achieved at an input power of only 3.7 W.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4851008','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4851008"><span id="translatedtitle">Accelerating Spaceborne <span class="hlt">SAR</span> Imaging Using Multiple CPU/GPU Deep Collaborative Computing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Fan; Li, Guojun; Li, Wei; Hu, Wei; Hu, Yuxin</p> <p>2016-01-01</p> <p>With the development of synthetic aperture radar (<span class="hlt">SAR</span>) technologies in recent years, the huge amount of remote sensing data brings challenges for real-time imaging processing. Therefore, high performance computing (HPC) methods have been presented to accelerate <span class="hlt">SAR</span> imaging, especially the GPU based methods. In the classical GPU based imaging algorithm, GPU is employed to accelerate image processing by massive parallel computing, and CPU is only used to perform the auxiliary work such as data input/output (IO). However, the computing capability of CPU is ignored and underestimated. In this work, a new deep collaborative <span class="hlt">SAR</span> imaging method based on multiple CPU/GPU is proposed to achieve real-time <span class="hlt">SAR</span> imaging. Through the proposed tasks partitioning and scheduling strategy, the whole image can be generated with deep collaborative multiple CPU/GPU computing. In the part of CPU parallel imaging, the advanced vector extension (AVX) method is firstly introduced into the multi-core CPU parallel method for higher efficiency. As for the GPU parallel imaging, not only the bottlenecks of memory limitation and frequent data transferring are broken, but also kinds of optimized strategies are applied, such as streaming, parallel pipeline and so on. Experimental results demonstrate that the deep CPU/GPU collaborative imaging method enhances the efficiency of <span class="hlt">SAR</span> imaging on single-core CPU by 270 times and realizes the real-time imaging in that the imaging <span class="hlt">rate</span> outperforms the raw data generation <span class="hlt">rate</span>. PMID:27070606</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27070606','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27070606"><span id="translatedtitle">Accelerating Spaceborne <span class="hlt">SAR</span> Imaging Using Multiple CPU/GPU Deep Collaborative Computing.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Fan; Li, Guojun; Li, Wei; Hu, Wei; Hu, Yuxin</p> <p>2016-01-01</p> <p>With the development of synthetic aperture radar (<span class="hlt">SAR</span>) technologies in recent years, the huge amount of remote sensing data brings challenges for real-time imaging processing. Therefore, high performance computing (HPC) methods have been presented to accelerate <span class="hlt">SAR</span> imaging, especially the GPU based methods. In the classical GPU based imaging algorithm, GPU is employed to accelerate image processing by massive parallel computing, and CPU is only used to perform the auxiliary work such as data input/output (IO). However, the computing capability of CPU is ignored and underestimated. In this work, a new deep collaborative <span class="hlt">SAR</span> imaging method based on multiple CPU/GPU is proposed to achieve real-time <span class="hlt">SAR</span> imaging. Through the proposed tasks partitioning and scheduling strategy, the whole image can be generated with deep collaborative multiple CPU/GPU computing. In the part of CPU parallel imaging, the advanced vector extension (AVX) method is firstly introduced into the multi-core CPU parallel method for higher efficiency. As for the GPU parallel imaging, not only the bottlenecks of memory limitation and frequent data transferring are broken, but also kinds of optimized strategies are applied, such as streaming, parallel pipeline and so on. Experimental results demonstrate that the deep CPU/GPU collaborative imaging method enhances the efficiency of <span class="hlt">SAR</span> imaging on single-core CPU by 270 times and realizes the real-time imaging in that the imaging <span class="hlt">rate</span> outperforms the raw data generation <span class="hlt">rate</span>. PMID:27070606</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140001452','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140001452"><span id="translatedtitle">Ionospheric Specifications for <span class="hlt">SAR</span> Interferometry (ISSI)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pi, Xiaoqing; Chapman, Bruce D; Freeman, Anthony; Szeliga, Walter; Buckley, Sean M.; Rosen, Paul A.; Lavalle, Marco</p> <p>2013-01-01</p> <p>The ISSI software package is designed to image the ionosphere from space by calibrating and processing polarimetric synthetic aperture radar (Pol<span class="hlt">SAR</span>) data collected from low Earth orbit satellites. Signals transmitted and received by a Pol<span class="hlt">SAR</span> are subject to the Faraday rotation effect as they traverse the magnetized ionosphere. The ISSI algorithms combine the horizontally and vertically polarized (with respect to the radar system) <span class="hlt">SAR</span> signals to estimate Faraday rotation and ionospheric total electron content (TEC) with spatial resolutions of sub-kilometers to kilometers, and to derive radar system calibration parameters. The ISSI software package has been designed and developed to integrate the algorithms, process Pol<span class="hlt">SAR</span> data, and image as well as visualize the ionospheric measurements. A number of tests have been conducted using ISSI with Pol<span class="hlt">SAR</span> data collected from various latitude regions using the phase array-type L-band synthetic aperture radar (PALSAR) onboard Japan Aerospace Exploration Agency's Advanced Land Observing Satellite mission, and also with Global Positioning System data. These tests have demonstrated and validated <span class="hlt">SAR</span>-derived ionospheric images and data correction algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......203W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......203W"><span id="translatedtitle">Geolocation with error analysis using imagery from an experimental spotlight <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wonnacott, William Mark</p> <p></p> <p>This dissertation covers the development of a geometry-based sensor model for a specific monostatic spotlight synthetic aperture radar (<span class="hlt">SAR</span>) system---referred to as the Ex<span class="hlt">SAR</span> (for experimental <span class="hlt">SAR</span>). This sensor model facilitates single- and multiple-image geopositioning with error analysis. It allows for the use of known ground control points in refining the collection geometry parameters (a process called image resection) and for the subsequent geopositioning of other points using the resected image. Theoretically, the model also allows for the potential recovery of bias-like, persistent errors common across multiple images. The model also includes multi-image correspondence equations to aid in the cross-image identification of conjugate points. The sensor model development begins with a generic, theoretical approach to the modeling of spotlight <span class="hlt">SAR</span>. A closed-form solution to the range and range-<span class="hlt">rate</span> condition equations and the corresponding error propagation equation are presented. (The <span class="hlt">SAR</span> condition equations have traditionally been solved iteratively.) The application of the closed-form solution in the image-to-ground and ground-to-image transformations is documented. The theoretical work also includes a preliminary error sensitivity analysis and a treatment of the spotlight <span class="hlt">SAR</span> resection process. The Ex<span class="hlt">SAR</span>-specific model is established and assessed with an extensive set of images collected using the experimental radar over arrays of ground control points. Using this set, the imagery metadata elements are assessed, and the optimal element set for geopositioning is determined. The Ex<span class="hlt">SAR</span> imagery is shown to be transformed to the ground plane in only one dimension. The eventual Ex<span class="hlt">SAR</span> sensor model is used with known elevations and single-image geopositioning to show a horizontal accuracy of 8.23 m (rms). With resection using five ground-surveyed control points per image, the horizontal accuracy of reserved check points is 0.45 m (rms). Resections using the same</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.G13B..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.G13B..07L"><span id="translatedtitle">In<span class="hlt">SAR</span> and GPS time series analysis: Crustal deformation in the Yucca Mountain, Nevada region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Z.; Hammond, W. C.; Blewitt, G.; Kreemer, C. W.; Plag, H.</p> <p>2010-12-01</p> <p>Several previous studies have successfully demonstrated that long time series (e.g. >5 years) of GPS measurements can be employed to detect tectonic signals with a vertical <span class="hlt">rate</span> greater than 0.3 mm/yr (e.g. Hill and Blewitt, 2006; Bennett et al. 2009). However, GPS stations are often sparse, with spacing from a few kilometres to a few hundred kilometres. Interferometric <span class="hlt">SAR</span> (In<span class="hlt">SAR</span>) can complement GPS by providing high horizontal spatial resolution (e.g. meters to tens-of metres) over large regions (e.g. 100 km × 100 km). A major source of error for repeat-pass In<span class="hlt">SAR</span> is the phase delay in radio signal propagation through the atmosphere. The portion of this attributable to tropospheric water vapour causes errors as large as 10-20 cm in deformation retrievals. In<span class="hlt">SAR</span> Time Series analysis with Atmospheric Estimation Models (In<span class="hlt">SAR</span> TS + AEM), developed at the University of Glasgow, is a robust time series analysis approach, which mainly uses interferograms with small geometric baselines to minimise the effects of decorrelation and inaccuracies in topographic data. In addition, In<span class="hlt">SAR</span> TS + AEM can be used to separate deformation signals from atmospheric water vapour effects in order to map surface deformation as it evolves in time. The principal purposes of this study are to assess: (1) how consistent In<span class="hlt">SAR</span>-derived deformation time series are with GPS; and (2) how precise In<span class="hlt">SAR</span>-derived atmospheric path delays can be. The Yucca Mountain, Nevada region is chosen as the study site because of its excellent GPS network and extensive radar archives (>10 years of dense and high-quality GPS stations, and >17 years of ERS and ENVISAT radar acquisitions), and because of its arid environment. The latter results in coherence that is generally high, even for long periods that span the existing C-band radar archives of ERS and ENVISAT. Preliminary results show that our In<span class="hlt">SAR</span> LOS deformation map agrees with GPS measurements to within 0.35 mm/yr RMS misfit at the stations which is the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.G43A0503J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.G43A0503J&link_type=ABSTRACT"><span id="translatedtitle">UAVSAR: In<span class="hlt">SAR</span> and Pol<span class="hlt">SAR</span> Test Bed for the Proposed NI-<span class="hlt">SAR</span> Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, C. E.; Hensley, S.; Lou, Y.</p> <p>2014-12-01</p> <p>UAVSAR, which first became operational in 2009, has served as an operational testbed for the NI-<span class="hlt">SAR</span> L-band radar concept and a unique instrument in its own right. UAVSAR supports a broad array of basic and applied geoscience, covering on smaller scale all the disciplines NI-<span class="hlt">SAR</span> would be able to address on a global scale. Although designed specifically to provide high accuracy repeated flight tracks and precise imaging geometry for In<span class="hlt">SAR</span>-based solid earth studies, its fully polarimetric operation, low noise, and consistent calibration accuracy has made it a premier instrument for Pol<span class="hlt">SAR</span>-based studies also. Since 2009 it has successfully imaged more than 16 million km2 and >4300 quad-polarimetric data products are now publicly available online. Upgrades made in the last year to automate the repeat track processing serve as a model for generating large volumes of In<span class="hlt">SAR</span> products: Since January 2014 more than 700 interferometric products have been released, exceeding the output of all previous years combined. Standardly available products now include browse images of all In<span class="hlt">SAR</span> acquisitions and coregistered single-look complex image stacks suitable for standard time series analysis. Here we present an overview of the wide range of studies utilizing UAVSAR data including those based on polarimetry and pair-wise and times series interferometry, highlighting both the unique capabilities of UAVSAR and the ways in which NI-<span class="hlt">SAR</span> would be able to dramatically extend the capabilities. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ794097.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ794097.pdf"><span id="translatedtitle">Online Health Education on <span class="hlt">SARS</span> to University Students during the <span class="hlt">SARS</span> Outbreak</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wong, Mee Lian; Koh, David; Iyer, Prasad; Seow, Adeline; Goh, Lee Gan; Chia, Sin Eng; Lim, Meng Kin; Ng, Daniel; Ong, Choon Nam; Phua, Kai Hong; Tambyah, Paul; Chow, Vincent T K; Chew, Suok Kai; Chandran, Ravi; Lee, Hin Peng</p> <p>2005-01-01</p> <p>Little is known about how online learning may be used to disseminate health information rapidly and widely to large university populations if there is an infectious disease outbreak. During the <span class="hlt">SARS</span> outbreak in Singapore in 2003, a six-lesson elearning module on <span class="hlt">SARS</span> was developed for a large university population of 32,000 students. The module…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1736.photos.042023p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1736.photos.042023p/"><span id="translatedtitle">23. OVERVIEW OF <span class="hlt">SAR</span>3 AREA, SHOWING CORNER OF <span class="hlt">SAR</span>3 WITH ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>23. OVERVIEW OF <span class="hlt">SAR</span>-3 AREA, SHOWING CORNER OF <span class="hlt">SAR</span>-3 WITH TAILRACE, ADMINISTRATIVE OFFICE, TOILET SHED, AND RETAINING WALLS AT FORMER EMPLOYEE HOUSING SITE. VIEW TO SOUTHEAST. PANORAMA 1/2. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('//www.loc.gov/pictures/collection/hh/item/ca1736.photos.042020p/','SCIGOV-HHH'); return false;" href="//www.loc.gov/pictures/collection/hh/item/ca1736.photos.042020p/"><span id="translatedtitle">20. OVERVIEW OF <span class="hlt">SAR</span>3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, <span class="hlt">SAR</span>3 ...</span></a></p> <p><a target="_blank" href="http://www.loc.gov/pictures/collection/hh/">Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey</a></p> <p></p> <p></p> <p>20. OVERVIEW OF <span class="hlt">SAR</span>-3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, <span class="hlt">SAR</span>-3 SWITCH RACK, MAINTENANCE YARD, AND GREENSPOT BRIDGE. NOTE ALSO LARGE PIPE CONDUCTING TAILRACE WATER INTO IRRIGATION SYSTEM. VIEW TO SOUTHWEST. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994SPIE.2238..238H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994SPIE.2238..238H"><span id="translatedtitle"><span class="hlt">SAR</span> imagery of moving targets: application of time-frequency distributions for estimating motion parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haimovich, Alexander M.; Peckham, C. D.; Teti, Joseph G., Jr.</p> <p>1994-06-01</p> <p>It is well known that targets moving along track within a Synthetic Aperture Radar (<span class="hlt">SAR</span>) field of view are imaged as defocused objects. The <span class="hlt">SAR</span> stripmap mode is tuned to stationary ground targets and the mismatch between the <span class="hlt">SAR</span> processing parameters and the target motion parameters causes the energy to spill over to adjacent image pixels, thus not only hindering target feature extraction, but also reducing the probability of detection. The problem can be remedied by generating the image using a filter matched to the actual target motion parameters, effectively focusing the <span class="hlt">SAR</span> image on the target. For a fixed <span class="hlt">rate</span> of motion the target velocity can be estimated from the slope of the Doppler frequency characteristic. The processing is carried out on the range compressed data but before azimuth compression. The problem is similar to the classical problem of estimating the instantaneous frequency of a linear FM signal (chirp). This paper investigates the application of three different time-frequency analysis techniques to estimate the instantaneous Doppler frequency of range compressed <span class="hlt">SAR</span> data. In particular, we compare the Wigner-Ville distribution, the Gabor expansion and the Short-Time Fourier transform with respect to their performance in noisy <span class="hlt">SAR</span> data. Criteria are suggested to quantify the performance of each method in the joint time- frequency domain. It is shown that these methods exhibit sharp signal-to-noise threshold effects, i.e., a certain SNR below which the accuracy of the velocity estimation deteriorates rapidly. It is also shown that the methods differ with respect to their representation of the <span class="hlt">SAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH13A1594E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH13A1594E"><span id="translatedtitle">A Detailed View of Rockslide Deformation Patterns in Northern Norway Using Both Ascending and Descending High-Resolution Terra<span class="hlt">SAR</span>-X Satellite In<span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eriksen, H.; Lauknes, T.; Dehls, J. F.; Larsen, Y.; Corner, G. D.</p> <p>2012-12-01</p> <p>Norway is particularly susceptible to large rockslides due to its many fjords and steep mountains. One of the most dangerous hazards related to rock slope failures are tsunamis that can lead to large loss of life. Many rockslides are clustered east of the Lyngen fjord in Troms county, northern Norway, where several mapped unstable rock slopes occur within the zone of sporadic permafrost. Among these, the Jettan rockslide at Nordnes has been classified as high-risk due to the severe consequences should catastrophic failure occur. In order to fully understand the kinematics and geometric configurations susceptible for sliding, it is imperative to obtain precise measurements of the stability of potential unstable rock slopes. Multi-temporal satellite interferometric synthetic aperture radar (In<span class="hlt">SAR</span>) techniques involve comparing the phase information from multiple spaceborne <span class="hlt">SAR</span> images, produced at different times, to detect millimeter to centimeter scale ground deformation patterns. However, the satellite radar is only capable of measuring displacement that has a component in the radar line-of-sight (LOS). By combining In<span class="hlt">SAR</span> data acquired in both ascending and descending orbits, it is possible to extract more information about the true displacement vector, increasing the interpretability of the displacement patterns. In this study, we apply multitemporal In<span class="hlt">SAR</span> methods to an extensive time series of Terra<span class="hlt">SAR</span>-X data collected in both ascending and descending geometries during the summer seasons in the period 2009-2012. The estimated deformation <span class="hlt">rates</span> from the ascending and descending geometries are decomposed into deformation in the vertical and east/west directions, dip angle and total deformation. For the study area, we present examples of the detailed deformation patterns obtained by using both ascending and descending <span class="hlt">SAR</span> data, together with mapped geological structures and geomorphological elements in the field. Finally, we validate the estimated displacement</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC21D0574H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC21D0574H"><span id="translatedtitle">Monitoring delta subsidence with Interferometric Synthetic Aperture Radar (In<span class="hlt">SAR</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Higgins, S.; Overeem, I.; Syvitski, J. P.</p> <p>2014-12-01</p> <p>Can subsidence in river deltas be monitored in near real-time at the spatial and temporal resolution needed for informing critical management decisions? Interferometric Synthetic Radar Aperture (In<span class="hlt">SAR</span>) is a satellite-based technique that can map ground deformation with millimeter-scale vertical resolution over thousands of square kilometers. In<span class="hlt">SAR</span> has enormous potential to shed light on the dynamics of actively subsiding deltas, but the technique is not commonly applied outside of major cities due to the difficulty of performing In<span class="hlt">SAR</span> in wet, vegetated settings. Given these limitations, how can In<span class="hlt">SAR</span> best serve the global effort to monitor sinking deltas? Here, an overview of In<span class="hlt">SAR</span> processing is provided that addresses delta-specific challenges, including frequent cloud-cover in tropical areas; noisy signals in wetlands and flooded fields; dense forests that interact unpredictably with different radar wavelengths; flat landscapes that hinder image stacking algorithms; rapid urban development that can render Digital Elevation Models (DEMs) inaccurate; and a lack of in situ GPS (Global Positioning System) receivers for In<span class="hlt">SAR</span> calibration. In<span class="hlt">SAR</span> has unique value for monitoring subsidence in deltas, and some natural and anthropogenic drivers of subsidence can be resolved by In<span class="hlt">SAR</span>. High-resolution In<span class="hlt">SAR</span> measurements from the Ganges-Brahmaputra Delta (GBD) are then presented and validated against GPS data. Surface motion is shown to reflect subsurface stratigraphy, and sediment compaction is shown to be the most important factor in this delta on short (non-tectonic) timescales. Average compaction <span class="hlt">rates</span> throughout the eastern delta range from 0 to > 18 mm/y, varying by more than an order of magnitude depending on the ages and grain sizes of surface and subsurface sediment layers. Fastest subsidence is observed in Holocene organic-rich mud, and slowest subsidence is observed along the Meghna River and in areas with surface or subsurface sand deposits. Although groundwater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESASP.722E.278S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESASP.722E.278S"><span id="translatedtitle">Bridge Deformation Monitoring: Instight From In<span class="hlt">SAR</span> Time-Series And Finite Element Modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shamshiri, Roghayeh; Motagh, Mahdi; Baes, Marzieh; Sharifi, Mohammad-Ali</p> <p>2013-12-01</p> <p>This paper presents the capability of advanced In<span class="hlt">SAR</span> time-series techniques such as Small BAseline Subset (SBAS) for monitoring of civil engineering structures like bridge. Deformation monitoring of bridges are essential to mitigate not only the financial and human losses, but also ecological and environmental-related problems. Assessment of deformation during bridge lifespan can provide invaluable insight for better planning and management. The study area, Lake Urmia Causeway (LUC) in northwest Iran, consists of one bridge and two embankments on both sides of it. The difference between the deformation <span class="hlt">rate</span> of the embankments on both sides of the bridge may seriously damage the bridge itself, so it is very important to accurately monitor them in space and time in order to assess the state of the bridge concerning deformations. In this study we apply the In<span class="hlt">SAR</span> time-series technique of SBAS for 58 <span class="hlt">SAR</span> images including 10 ALOS, 30 Envisat and 18 Terra<span class="hlt">SAR</span>-X (TSX) to assess deflation of embankments of Urmia bridge during 2003-2013. The In<span class="hlt">SAR</span> results are used in a 2D Finite Element Model (FEM) to assess structural stability of the embankments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70036617','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70036617"><span id="translatedtitle">Quantifying sub-pixel urban impervious surface through fusion of optical and in<span class="hlt">SAR</span> imagery</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Yang, L.; Jiang, L.; Lin, H.; Liao, M.</p> <p>2009-01-01</p> <p>In this study, we explored the potential to improve urban impervious surface modeling and mapping with the synergistic use of optical and Interferometric Synthetic Aperture Radar (In<span class="hlt">SAR</span>) imagery. We used a Classification and Regression Tree (CART)-based approach to test the feasibility and accuracy of quantifying Impervious Surface Percentage (ISP) using four spectral bands of SPOT 5 high-resolution geometric (HRG) imagery and three parameters derived from the European Remote Sensing (ERS)-2 Single Look Complex (SLC) <span class="hlt">SAR</span> image pair. Validated by an independent ISP reference dataset derived from the 33 cm-resolution digital aerial photographs, results show that the addition of In<span class="hlt">SAR</span> data reduced the ISP modeling error <span class="hlt">rate</span> from 15.5% to 12.9% and increased the correlation coefficient from 0.71 to 0.77. Spatially, the improvement is especially noted in areas of vacant land and bare ground, which were incorrectly mapped as urban impervious surfaces when using the optical remote sensing data. In addition, the accuracy of ISP prediction using In<span class="hlt">SAR</span> images alone is only marginally less than that obtained by using SPOT imagery. The finding indicates the potential of using In<span class="hlt">SAR</span> data for frequent monitoring of urban settings located in cloud-prone areas. Copyright ?? 2009 by Bellwether Publishing, Ltd. All right reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26691595','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26691595"><span id="translatedtitle">Resilience of <span class="hlt">SAR</span>11 bacteria to rapid acidification in the high-latitude open ocean.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hartmann, Manuela; Hill, Polly G; Tynan, Eithne; Achterberg, Eric P; Leakey, Raymond J G; Zubkov, Mikhail V</p> <p>2016-02-01</p> <p>Ubiquitous <span class="hlt">SAR</span>11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short-term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of <span class="hlt">SAR</span>11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic <span class="hlt">SAR</span>11. This study investigated the effect of 2.5-fold acidification of seawater on the metabolism of <span class="hlt">SAR</span>11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake <span class="hlt">rates</span> of the amino acid leucine by <span class="hlt">SAR</span>11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects. PMID:26691595</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22389587','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22389587"><span id="translatedtitle">Permanent Scatterer In<span class="hlt">SAR</span> Analysis and Validation in the Gulf of Corinth.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Elias, Panagiotis; Kontoes, Charalabos; Papoutsis, Ioannis; Kotsis, Ioannis; Marinou, Aggeliki; Paradissis, Dimitris; Sakellariou, Dimitris</p> <p>2009-01-01</p> <p>The Permanent Scatterers Interferometric <span class="hlt">SAR</span> technique (PSIn<span class="hlt">SAR</span>) is a method that accurately estimates the near vertical terrain deformation <span class="hlt">rates</span>, of the order of ∼1 mm year(-1), overcoming the physical and technical restrictions of classic In<span class="hlt">SAR</span>. In this paper the method is strengthened by creating a robust processing chain, incorporating PSIn<span class="hlt">SAR</span> analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs) and Permanent Scatterers (PSs) selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ∼2.5 mm year(-1) occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSIn<span class="hlt">SAR</span> technique. PMID:22389587</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3280733','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3280733"><span id="translatedtitle">Permanent Scatterer In<span class="hlt">SAR</span> Analysis and Validation in the Gulf of Corinth</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Elias, Panagiotis; Kontoes, Charalabos; Papoutsis, Ioannis; Kotsis, Ioannis; Marinou, Aggeliki; Paradissis, Dimitris; Sakellariou, Dimitris</p> <p>2009-01-01</p> <p>The Permanent Scatterers Interferometric <span class="hlt">SAR</span> technique (PSIn<span class="hlt">SAR</span>) is a method that accurately estimates the near vertical terrain deformation <span class="hlt">rates</span>, of the order of ∼1 mm year-1, overcoming the physical and technical restrictions of classic In<span class="hlt">SAR</span>. In this paper the method is strengthened by creating a robust processing chain, incorporating PSIn<span class="hlt">SAR</span> analysis together with algorithmic adaptations for Permanent Scatterer Candidates (PSCs) and Permanent Scatterers (PSs) selection. The processing chain, called PerSePHONE, was applied and validated in the geophysically active area of the Gulf of Corinth. The analysis indicated a clear subsidence trend in the north-eastern part of the gulf, with the maximum deformation of ∼2.5 mm year-1 occurring in the region north of the Gulf of Alkyonides. The validity of the results was assessed against geophysical/geological and geodetic studies conducted in the area, which include continuous seismic profiling data and GPS height measurements. All these observations converge to the same deformation pattern as the one derived by the PSIn<span class="hlt">SAR</span> technique. PMID:22389587</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9260E..1SL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9260E..1SL"><span id="translatedtitle">A novel high resolution wide swath <span class="hlt">SAR</span> based on waveform design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Bo</p> <p>2014-11-01</p> <p>Spaceborne Synthetic Aperture Radar (<span class="hlt">SAR</span>), with "all weather", day or night imaging capabilities, has been playing an important role in the domination of Earth observation. Spaceborne high-resolution wide-swath <span class="hlt">SAR</span> (HRWS-<span class="hlt">SAR</span>) can quickly obtain wide range of the earth's surface information, which is of great significance to Earth mapping, geological exploration, vegetation and biomass estimates, marine monitoring, target search, disaster relief, etc. As a result, spaceborne HRWS-<span class="hlt">SAR</span> has been gaining more and more attention. However, considering the restrictions on pulse repetition frequency (PRF) and power-aperture product, space-based <span class="hlt">SAR</span> imaging cannot achieve high resolution and wide swath at the same time. Currently existing solutions mainly focus on the antenna system hardware devices, such as MIMO, DBF; other signal-processing-bias solutions, such as Mosaic imaging technology, have higher requirements of the antenna pointing or beam control. These methods adopt more antenna elements or complex beam control method, which greatly increased the demand for hardware performance, and the signal processing method become more complicated as well. In order to relieve the pressure on the system hardware devices, this paper presents a new orthogonal coded waveform method based on the theory of communication. By using this method, the LFM signal is coded by the orthogonal codes to make the inter-pulse waveform irrelevant, which ensures the azimuth sampling <span class="hlt">rate</span> as well as a wide swath. Theoretically, this method can alleviate the contradiction between PRF and high resolution wide swath imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3322939','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3322939"><span id="translatedtitle">Cluster of <span class="hlt">SARS</span> among Medical Students Exposed to Single Patient, Hong Kong</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Chin-kei; Tam, Wilson; Lau, Joseph Tak-fai; Yu, Tak-sun; Lui, Siu-fai; Chan, Paul K.S.; Li, Yuguo; Bresee, Joseph S.; Sung, Joseph J.Y.; Parashar, Umesh D.</p> <p>2004-01-01</p> <p>We studied transmission patterns of severe acute respiratory syndrome (<span class="hlt">SARS</span>) among medical students exposed exclusively to the first <span class="hlt">SARS</span> patient in the Prince of Wales Hospital in Hong Kong, before his illness was recognized. We conducted a retrospective cohort study of 66 medical students who visited the index patient’s ward, including 16 students with <span class="hlt">SARS</span> and 50 healthy students. The risk of contracting <span class="hlt">SARS</span> was sevenfold greater among students who definitely visited the index case’s cubicle than in those who did not (10/27 [41%] versus 1/20 [5%], relative risk [RR] 7.4; 95% confidence interval [CI] 1.0 to 53.3). Illness <span class="hlt">rates</span> increased directly with proximity of exposure to the index case. However, four of eight students who were in the same cubicle, but were not within 1 m of the index case-patient, contracted <span class="hlt">SARS</span>. Proximity to the index case-patient was associated with transmission, which is consistent with droplet spread. Transmission through fomites or small aerosols cannot be ruled out. PMID:15030696</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT.......252B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT.......252B"><span id="translatedtitle">Motion compensation for aircraft-borne interferometric <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bullock, Richard John</p> <p></p> <p>This research has studied data driven techniques for roll compensation for aircraft-borne In<span class="hlt">SAR</span>, for platforms where an accurate Inertial Navigation Unit (INU) is inappropriate due to limitations on weight or cost, such as a low-cost civilian mapping system or a miniature UAV. It is shown that for unknown topography, roll errors cannot simply be filtered from the interferogram due to a fundamental ambiguity between aircraft roll effects and certain types of undulating terrain. The solution to this problem lies in the differential Doppler shifts of the signals received at the two antennas. These are proportional to the aircraft roll <span class="hlt">rate</span> and can be extracted by incoherent or coherent means and utilised to reconstruct the aircraft roll history. This research analyses, experimentally evaluates and further develops the incoherent Differential Doppler (DD) method for roll compensation, developed to the proof-of-concept stage by A. Currie at QinetiQ (Malvern) and compares this with the two-look method, which is a novel coherent technique developed, analysed and experimentally evaluated as part of this PhD from an original idea proposed by Prof. R. Voles of UCL. By means of empirical analysis, numerical simulation and real test data from the QinetiQ C-Band In<span class="hlt">SAR</span>, it is shown that the two-look method offers significant advantages in sensitivity, frequency performance, robustness and efficiency of implementation over the DD method, particularly at long range. The experimental results also show that for the QinetiQ C-Band In<span class="hlt">SAR</span>, the two-look method provides roll compensation to a similar quality or better than provided by the on-board Litton-93 INU, which has a specified accuracy of +/-0.05°. Ambiguities in the roll <span class="hlt">rate</span> estimates from other motions are also shown to be small for this platform, and could be reduced further by employing differential GPS track compensation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993GeoRL..20.1439M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993GeoRL..20.1439M"><span id="translatedtitle">An evaluation of the <span class="hlt">rate</span> of <span class="hlt">absorption</span> of solar radiation in the O2(X3Sigma-g - b1Sigma-g) transition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mlynczak, Martin G.</p> <p>1993-07-01</p> <p>The <span class="hlt">rate</span> at which molecular oxygen absorbs radiation in the O2(X3Sigma-g - b1Sigma-g) transition is calculated using a line-by-line radiative transfer model. This <span class="hlt">rate</span> is critical to the determination of the population of the O2(b1Sigma-g) state required for studies of the O2(b1Sigma-g - X3Sigma-g) dayglow, the O2(a1Delta-g - X3Sigma-g) dayglow, and possibly the <span class="hlt">rates</span> of oxidation of H2 and N2O. Previous evaluations of this <span class="hlt">rate</span> (which is sometimes called the g-factor) have significantly overestimated its value. The <span class="hlt">rate</span> is tabulated as a function of altitude, pressure, and solar zenith angle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930069261&hterms=N2O+Absorption+Lines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DN2O%2BAbsorption%2BLines','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930069261&hterms=N2O+Absorption+Lines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DN2O%2BAbsorption%2BLines"><span id="translatedtitle">An evaluation of the <span class="hlt">rate</span> of <span class="hlt">absorption</span> of solar radiation in the O2(X3Sigma-g - b1Sigma-g) transition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mlynczak, Martin G.</p> <p>1993-01-01</p> <p>The <span class="hlt">rate</span> at which molecular oxygen absorbs radiation in the O2(X3Sigma-g - b1Sigma-g) transition is calculated using a line-by-line radiative transfer model. This <span class="hlt">rate</span> is critical to the determination of the population of the O2(b1Sigma-g) state required for studies of the O2(b1Sigma-g - X3Sigma-g) dayglow, the O2(a1Delta-g - X3Sigma-g) dayglow, and possibly the <span class="hlt">rates</span> of oxidation of H2 and N2O. Previous evaluations of this <span class="hlt">rate</span> (which is sometimes called the g-factor) have significantly overestimated its value. The <span class="hlt">rate</span> is tabulated as a function of altitude, pressure, and solar zenith angle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10468077','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10468077"><span id="translatedtitle">Aspirin <span class="hlt">absorption</span> <span class="hlt">rates</span> and platelet inhibition times with 325-mg buffered aspirin tablets (chewed or swallowed intact) and with buffered aspirin solution.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Feldman, M; Cryer, B</p> <p>1999-08-15</p> <p>Large clinical trials such as the second International Study of Infarct Survival routinely gave patients with myocardial infarction a chewed aspirin, yet there are no data to show whether chewing of aspirin is better, or worse, than swallowing a whole tablet. We performed a randomized, placebo-controlled study to determine whether chewing aspirin or administering it in solution accelerates its <span class="hlt">absorption</span> and antiplatelet activity. On separate days, 12 fasting volunteers ingested 325 mg of buffered aspirin, either by chewing a tablet for 30 seconds before swallowing it with 4 ounces of water, swallowing a whole tablet with 4 ounces of water, or drinking 4 ounces of Alka Seltzer. Frequent blood samples were obtained for serum aspirin, salicylate, and thromboxane B2 (TxB2) concentrations. With all formulations of aspirin, serum TxB2 decreased 50% when the plasma aspirin concentration reached approximately 1,000 ng/ml. A 50% and 90% decrease in serum TxB2 occurred more quickly after chewing a tablet than after a tablet was swallowed whole. For example, the t 50% for serum TxB2 inhibition was 5.0 +/- 0.6 minutes with the chewed tablet versus 12.0 +/- 2.3 minutes when the tablet was swallowed (p = 0.01). A 50% decrease in serum TxB2 occurred 7.6 +/- 1.2 minutes after Alka Seltzer solution (p = 0.04 vs chewing a tablet; p = 0.13 vs swallowing a whole tablet). Chewing an aspirin tablet is the most effective way of accelerating <span class="hlt">absorption</span> of aspirin into the blood and shortening the time required for an antiplatelet effect. PMID:10468077</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1221971','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1221971"><span id="translatedtitle">Pre-processing <span class="hlt">SAR</span> image stream to facilitate compression for transport on bandwidth-limited-link</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rush, Bobby G.; Riley, Robert</p> <p>2015-09-29</p> <p>Pre-processing is applied to a raw Video<span class="hlt">SAR</span> (or similar near-video <span class="hlt">rate</span>) product to transform the image frame sequence into a product that resembles more closely the type of product for which conventional video codecs are designed, while sufficiently maintaining utility and visual quality of the product delivered by the codec.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9646E..0CJ&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9646E..0CJ&link_type=ABSTRACT"><span id="translatedtitle">APES-based procedure for super-resolution <span class="hlt">SAR</span> imagery with GPU parallel computing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jia, Weiwei; Xu, Xiaojian; Xu, Guangyao</p> <p>2015-10-01</p> <p>The amplitude and phase estimation (APES) algorithm is widely used in modern spectral analysis. Compared with conventional Fourier transform (FFT), APES results in lower sidelobes and narrower spectral peaks. However, in synthetic aperture radar (<span class="hlt">SAR</span>) imaging with large scene, without parallel computation, it is difficult to apply APES directly to super-resolution radar image processing due to its great amount of calculation. In this paper, a procedure is proposed to achieve target extraction and parallel computing of APES for super-resolution <span class="hlt">SAR</span> imaging. Numerical experimental are carried out on Tesla K40C with 745 MHz GPU clock <span class="hlt">rate</span> and 2880 CUDA cores. Results of <span class="hlt">SAR</span> image with GPU parallel computing show that the parallel APES is remarkably more efficient than that of CPU-based with the same super-resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870065958&hterms=giga&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgiga','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870065958&hterms=giga&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgiga"><span id="translatedtitle">Spacecraft on-board <span class="hlt">SAR</span> image generation for EOS-type missions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, K. Y.; Arens, W. E.; Assal, H. M.; Vesecky, J. F.</p> <p>1987-01-01</p> <p>Spacecraft on-board synthetic aperture radar (<span class="hlt">SAR</span>) image generation is an extremely difficult problem because of the requirements for high computational <span class="hlt">rates</span> (usually on the order of Giga-operations per second), high reliability (some missions last up to 10 years), and low power dissipation and mass (typically less than 500 watts and 100 Kilograms). Recently, a JPL study was performed to assess the feasibility of on-board <span class="hlt">SAR</span> image generation for EOS-type missions. This paper summarizes the results of that study. Specifically, it proposes a processor architecture using a VLSI time-domain parallel array for azimuth correlation. Using available space qualifiable technology to implement the proposed architecture, an on-board <span class="hlt">SAR</span> processor having acceptable power and mass characteristics appears feasible for EOS-type applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApPhB.108..721S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApPhB.108..721S"><span id="translatedtitle">Doppler-limited H2O and HF <span class="hlt">absorption</span> spectroscopy by sweeping the 1,321-1,354 nm range at 55 kHz repetition <span class="hlt">rate</span> using a single-mode MEMS-tunable VCSEL</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stein, B. A.; Jayaraman, V.; Jiang, J. Y.; Cable, A.; Sanders, S. T.</p> <p>2012-09-01</p> <p>A single longitudinal mode micro-electro-mechanical system-tunable vertical cavity surface-emitting laser (VCSEL) was used to measure H2O and HF <span class="hlt">absorption</span> spectra in the 1,321-1,354 nm range at 55 kHz repetition <span class="hlt">rate</span> (˜ 740 MHz/ns tuning <span class="hlt">rate</span>). Pulse delay referencing was used to achieve an absorbance noise level of 0.004 (RMS), within a factor of 2.6 of the shot noise limit. The measured linewidths approach the low-pressure feature linewidths (˜790 MHz) characteristic of the gases studied, highlighting the single-mode nature of the VCSEL throughout each rapid wavelength sweep. At even higher tuning <span class="hlt">rates</span>, molecular features became asymmetric and broad, consistent with rapid passage and Fourier effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10104849','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10104849"><span id="translatedtitle">A comparative evaluation of <span class="hlt">SAR</span> and SLAR</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mastin, G.A.; Manson, J.J.; Bradley, J.D.; Axline, R.M.; Hover, G.L.</p> <p>1993-11-01</p> <p>Synthetic aperture radar (<span class="hlt">SAR</span>) was evaluated as a potential technological improvement over the Coast Guard`s existing side-looking airborne radar (SLAR) for oil-spill surveillance applications. The US Coast Guard Research and Development Center (R&D Center), Environmental Branch, sponsored a joint experiment including the US Coast Guard, Sandia National Laboratories, and the Naval Oceanographic and Atmospheric Administration (NOAA), Hazardous Materials Division. Radar imaging missions were flown on six days over the coastal waters off Santa Barbara, CA, where there are constant natural seeps of oil. Both the Coast Guard SLAR and the Sandia National Laboratories <span class="hlt">SAR</span> were employed to acquire simultaneous images of oil slicks and other natural sea surface features that impact oil-spill interpretation. Surface truth and other environmental data were also recorded during the experiment. The experiment data were processed at Sandia National Laboratories and delivered to the R&D Center on a computer workstation for analysis by experiment participants. Issues such as optimal spatial resolution, single-look vs. multi-look <span class="hlt">SAR</span> imaging, and the utility of <span class="hlt">SAR</span> for oil-spill analysis were addressed. Finally, conceptual design requirements for a possible future Coast Guard <span class="hlt">SAR</span> were outlined and evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/14620481','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/14620481"><span id="translatedtitle">ICAO's anti-<span class="hlt">SARS</span> airport activities.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Finkelstein, Silvio; Curdt-Christiansen, Claus M</p> <p>2003-11-01</p> <p>To prevent <span class="hlt">SARS</span> from spreading through air travel and in order to rebuild the confidence of the traveling public in the safety of air travel, ICAO has set up an "Anti-<span class="hlt">SARS</span> Airport Evaluation Project." The first phase of this project was to develop a set of protective measures for international airports in affected areas to adopt and implement and then to send out, on the request of Contracting States, a team of inspectors to evaluate and assess airports and issue a "statement of evaluation" that the airport inspected complies with the ICAO anti-<span class="hlt">SARS</span> protective measures. In cooperation with the World Health Organization (WHO), the first part of phase 1 was completed in early June this year, and the second part of phase 1 followed soon after. By mid-July, five international airports in Southeast Asia had been inspected and found to be in full compliance with the ICAO anti-<span class="hlt">SARS</span> protective measures. The success of this ICAO project is believed to have contributed significantly to the recovery of international air travel and related industries now taking place. Phase 2 of the project is now being developed. It is aimed at preventing a resurgence of <span class="hlt">SARS</span>, but it also contains elements to make the methodology developed applicable to future outbreaks of any other communicable disease in which the mode of transmission could involve aviation and/or the need to prevent the spread of the disease by air travel. PMID:14620481</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8051E..0WR','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8051E..0WR"><span id="translatedtitle">Low complexity efficient raw <span class="hlt">SAR</span> data compression</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rane, Shantanu; Boufounos, Petros; Vetro, Anthony; Okada, Yu</p> <p>2011-06-01</p> <p>We present a low-complexity method for compression of raw Synthetic Aperture Radar (<span class="hlt">SAR</span>) data. Raw <span class="hlt">SAR</span> data is typically acquired using a satellite or airborne platform without sufficient computational capabilities to process the data and generate a <span class="hlt">SAR</span> image on-board. Hence, the raw data needs to be compressed and transmitted to the ground station, where <span class="hlt">SAR</span> image formation can be carried out. To perform low-complexity compression, our method uses 1-dimensional transforms, followed by quantization and entropy coding. In contrast to previous approaches, which send uncompressed or Huffman-coded bits, we achieve more efficient entropy coding using an arithmetic coder that responds to a continuously updated probability distribution. We present experimental results on compression of raw Ku-<span class="hlt">SAR</span> data. In those we evaluate the effect of the length of the transform on compression performance and demonstrate the advantages of the proposed framework over a state-of-the-art low complexity scheme called Block Adaptive Quantization (BAQ).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3322904','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3322904"><span id="translatedtitle">Possible <span class="hlt">SARS</span> Coronavirus Transmission during Cardiopulmonary Resuscitation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Loutfy, Mona; McDonald, L. Clifford; Martinez, Kenneth F.; Ofner, Mariana; Wong, Tom; Wallington, Tamara; Gold, Wayne L.; Mederski, Barbara; Green, Karen; Low, Donald E.</p> <p>2004-01-01</p> <p>Infection of healthcare workers with the severe acute respiratory syndrome–associated coronavirus (<span class="hlt">SARS</span>-CoV) is thought to occur primarily by either contact or large respiratory droplet transmission. However, infrequent healthcare worker infections occurred despite the use of contact and droplet precautions, particularly during certain aerosol-generating medical procedures. We investigated a possible cluster of <span class="hlt">SARS</span>-CoV infections in healthcare workers who used contact and droplet precautions during attempted cardiopulmonary resuscitation of a <span class="hlt">SARS</span> patient. Unlike previously reported instances of transmission during aerosol-generating procedures, the index case-patient was unresponsive, and the intubation procedure was performed quickly and without difficulty. However, before intubation, the patient was ventilated with a bag-valve-mask that may have contributed to aerosolization of <span class="hlt">SARS</span>-CoV. On the basis of the results of this investigation and previous reports of <span class="hlt">SARS</span> transmission during aerosol-generating procedures, a systematic approach to the problem is outlined, including the use of the following: 1) administrative controls, 2) environmental engineering controls, 3) personal protective equipment, and 4) quality control. PMID:15030699</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16830005','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16830005"><span id="translatedtitle"><span class="hlt">SARS</span> revisited: managing "outbreaks" with "communications".</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Menon, K U</p> <p>2006-05-01</p> <p>"Risk communications" has acquired some importance in the wake of our experience of <span class="hlt">SARS</span>. Handled well, it helps to build mutual respect between a government or an organisation and the target groups with which it is communicating. It helps nurture public trust and confidence in getting over the crisis. The World Health Organization (WHO) has also come to recognise its importance after <span class="hlt">SARS</span> and organised the first Expert Consultation on Outbreak Communications conference in Singapore in September 2004. This article assesses the context and the key features which worked to Singapore's advantage. Looking at the data now widely available on the Internet of the experience of <span class="hlt">SARS</span>-infected countries like China, Taiwan, Canada, the article identifies the key areas of strategic communications in which Singapore fared particularly well. Another issue discussed is whether Singapore's experience has universal applicability or whether it is limited because of Singapore's unique cultural, historical and geographical circumstances. Finally, the article also looks at some of the post-<span class="hlt">SARS</span> enhancements that have been put in place following the lessons learnt from <span class="hlt">SARS</span> and the need to confront new infectious outbreaks like avian flu. PMID:16830005</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930000806&hterms=texture&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dtexture','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930000806&hterms=texture&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dtexture"><span id="translatedtitle">Statistical Approach To Determination Of Texture In <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rignot, Eric J.; Kwok, Ronald</p> <p>1993-01-01</p> <p>Paper presents statistical approach to analysis of texture in synthetic-aperture-radar (<span class="hlt">SAR</span>) images. Objective: to extract intrinsic spatial variability of distributed target from overall spatial variability of <span class="hlt">SAR</span> image.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15141376','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15141376"><span id="translatedtitle">Organ distribution of severe acute respiratory syndrome (<span class="hlt">SARS</span>) associated coronavirus (<span class="hlt">SARS</span>-CoV) in <span class="hlt">SARS</span> patients: implications for pathogenesis and virus transmission pathways.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Yanqing; He, Li; Zhang, Qingling; Huang, Zhongxi; Che, Xiaoyan; Hou, Jinlin; Wang, Huijun; Shen, Hong; Qiu, Liwen; Li, Zhuguo; Geng, Jian; Cai, Junjie; Han, Huixia; Li, Xin; Kang, Wei; Weng, Desheng; Liang, Ping; Jiang, Shibo</p> <p>2004-06-01</p> <p>We previously identified the major pathological changes in the respiratory and immune systems of patients who died of severe acute respiratory syndrome (<span class="hlt">SARS</span>) but gained little information on the organ distribution of <span class="hlt">SARS</span>-associated coronavirus (<span class="hlt">SARS</span>-CoV). In the present study, we used a murine monoclonal antibody specific for <span class="hlt">SARS</span>-CoV nucleoprotein, and probes specific for a <span class="hlt">SARS</span>-CoV RNA polymerase gene fragment, for immunohistochemistry and in situ hybridization, respectively, to detect <span class="hlt">SARS</span>-CoV systematically in tissues from patients who died of <span class="hlt">SARS</span>. <span class="hlt">SARS</span>-CoV was found in lung, trachea/bronchus, stomach, small intestine, distal convoluted renal tubule, sweat gland, parathyroid, pituitary, pancreas, adrenal gland, liver and cerebrum, but was not detected in oesophagus, spleen, lymph node, bone marrow, heart, aorta, cerebellum, thyroid, testis, ovary, uterus or muscle. These results suggest that, in addition to the respiratory system, the gastrointestinal tract and other organs with detectable <span class="hlt">SARS</span>-CoV may also be targets of <span class="hlt">SARS</span>-CoV infection. The pathological changes in these organs may be caused directly by the cytopathic effect mediated by local replication of the <span class="hlt">SARS</span>-CoV; or indirectly as a result of systemic responses to respiratory failure or the harmful immune response induced by viral infection. In addition to viral spread through a respiratory route, <span class="hlt">SARS</span>-CoV in the intestinal tract, kidney and sweat glands may be excreted via faeces, urine and sweat, thereby leading to virus transmission. This study provides important information for understanding the pathogenesis of <span class="hlt">SARS</span>-CoV infection and sheds light on possible virus transmission pathways. This data will be useful for designing new strategies for prevention and treatment of <span class="hlt">SARS</span>. PMID:15141376</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H43H1643K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H43H1643K"><span id="translatedtitle">Characterizing hydrologic changes of Great Dismal Swamp using <span class="hlt">SAR/InSAR</span> technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, J. W.; Lu, Z.; Zhu, Z.</p> <p>2015-12-01</p> <p>Great Dismal Swamp is one of the largest, northernmost peatlands on the Atlantic Coastal Plain, and the swamp is underlain by a thick water-logged organic soil layer (peat) made up of dead and decaying plant material. The peatlands play a role as the sink of large amount of soil organic carbon and methane. However, the disturbance of the peatland negatively impacted the ecosystem and contributed to the climate change caused by the released greenhouse gas. Our <span class="hlt">SAR/InSAR</span> methods observed the hydrologic changes in the peatlands, which is a key factor to conserve the wetland, through several methods. First, we compared averaged <span class="hlt">SAR</span> intensity from C- and L-band <span class="hlt">SAR</span> sensors with groundwater level changes, and deduced a linear relationship between the <span class="hlt">SAR</span> backscattering intensity and the groundwater level change. Second, we extracted the inundated area during wet season from In<span class="hlt">SAR</span> coherence. Third, we measured the relative water level changes in the inundated area using the interferometric phases. Finally, we estimated the groundwater level changes corresponding to the soil moisture changes from time-series In<span class="hlt">SAR</span> method. Our results can provide the unique opportunity to understand the occurring hydrologic and vegetation changes in the Great Dismal Swamp.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS32B..05A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS32B..05A"><span id="translatedtitle">Coastal Sea Level From CRYOSAT-2 <span class="hlt">SAR</span> and <span class="hlt">SAR</span>-In Altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andersen, O. B.; Abulaitijiang, A.; Knudsen, P.; Stenseng, L.</p> <p>2014-12-01</p> <p>Cryosat-2 offers the first ever possibility to perform coastal altimetric studies using bor <span class="hlt">SAR</span>-altimetry and <span class="hlt">SAR</span>-In altimetry. With this technological leap forward Cryosat-2 is now able to observe sea level in very small water bodies and also to provide coastal sea level very close to the shore. We perform an investigation into the retrieval of sea surface height around Denmark and Greenland. These regions have been chosen as the coastal regions around Denmark falls within the <span class="hlt">SAR</span> mask and the coastal regions of Greenland falls in under the <span class="hlt">SAR</span>-in mask employed on Cryosat-2. <span class="hlt">SAR</span>-in was mainly used in coastal regions of Greenland because of its huge topographic changes as Cryosat-2 is designed to map the margins of the ice-sheet. The coastal region around Denmark is a test region of the EU FP7 sponsored project LOTUS esablishing <span class="hlt">SAR</span> altimetry product in preparation for Sentinel-3. With the increased spatial resolution of Cryosat-2 <span class="hlt">SAR</span> we provide valuable sea level observations within the Straits around Denmark which are crucial to constrain the waterflow in and out of the Baltic Sea. The investigation of <span class="hlt">SAR</span>-in data in Greenland adds an entire new dimension to coastal altimetry. An amazing result of the investigation is the ability of Cryosat-2 to detect and recover sea level even though the coast (sealevel) is up to 15 km away from the nadir location of the satellite. This ability of capture and use returns from outside the main (-3Db) loop in theory enables Cryosat-2 <span class="hlt">SAR</span>-in to map sea level height of fjords more frequently than the 369 days repeat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984laus.iafcZ....M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984laus.iafcZ....M"><span id="translatedtitle">The Radarsat <span class="hlt">SAR</span> multi-beam antenna</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martins-Camelo, L.; Cooper, R. T.; Zimcik, D. G.</p> <p>1984-10-01</p> <p>Radarsat, the Canadian radar imaging satellite, will have a Synthetic Aperture Radar (<span class="hlt">SAR</span>) antenna as one of its sensors. The requirements on the performance of the <span class="hlt">SAR</span> antenna are such as to make it a complex system. Radarsat is required to have some unique characteristics which present some new challenges to the antenna designers. The requirements for switchability among 4 shaped beams and high power of transmit operation are major design constraints which strongly impact on the antenna complexity, weight, and cost. A trade-off study was carried out to select the preferred antenna type for the Radarsat <span class="hlt">SAR</span> function. The antenna types analyzed were planar-array and array-fed reflector. A set of comparison criteria was developed. The antenna concepts studied were then compared against these criteria, and a final decision was reached.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3720..123S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3720..123S"><span id="translatedtitle">Super resolution for FOPEN <span class="hlt">SAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shekarforoush, Hassan; Banerjee, Amit; Chellappa, Rama</p> <p>1999-07-01</p> <p>Detecting targets occluded by foliage in Foliage penetrating (FOPEN) Ultra-Wide-Band Synthetic Aperture Radar (UWB <span class="hlt">SAR</span>) images is an important and challenging problem. Given the different nature of FOPEN <span class="hlt">SAR</span> imagery and very low signal- to-clutter ratio in UWB <span class="hlt">SAR</span> data, conventional detection algorithms usually fail to yield robust target detection results on raw data with minimum false alarms. Hence improving the resolving power by means of a super-resolution algorithm plays an important role in hypothesis testing for false alarm mitigation and target localization. In this paper we present a new single-frame super-resolution algorithm based on estimating the polyphase components of the observed signal projected on an optimal basis. The estimated polyphase components are then combined into a single super-resolved image using the standard inverse polyphase transform, leading to improved target signature while suppressing noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920065615&hterms=Yellowstone+National+Park&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528%2528Yellowstone%2BNational%2529%2BPark%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920065615&hterms=Yellowstone+National+Park&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528%2528Yellowstone%2BNational%2529%2BPark%2529"><span id="translatedtitle">New approaches in interferometric <span class="hlt">SAR</span> data processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, Qian; Vesecky, John F.; Zebker, Howard A.</p> <p>1992-01-01</p> <p>It is well established that interferometric synthetic aperture radar (<span class="hlt">SAR</span>) images can be inverted to perform surface elevation mapping. Among the factors critical to the mapping accuracy are registration of the interfering <span class="hlt">SAR</span> images and phase unwrapping. A novel registration algorithm is presented that determines the registration parameters through optimization. A new figure of merit is proposed that evaluates the registration result during the optimization. The phase unwrapping problem is approached through a new method involving fringe line detection. The algorithms are tested with two SEASAT <span class="hlt">SAR</span> images of terrain near Yellowstone National Park. These images were collected on Seasat orbits 1334 and 1420, which were very close together in space, i.e., less than 100 m. The resultant elevation map is compared with the USGS digital terrain elevation model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004SPIE.5405...98W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004SPIE.5405...98W&link_type=ABSTRACT"><span id="translatedtitle">Stop outbreak of <span class="hlt">SARS</span> with infrared cameras</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Yigang M.</p> <p>2004-04-01</p> <p><span class="hlt">SARS</span> (Severe Acute Respiratory Syndrome, commonly known as Atypical Pneumonia in mainland China) caused 8422 people affected and resulting in 918 deaths worldwide in half year. This disease can be transmitted by respiratory droplets or by contact with a patient's respiratory secretions. This means it can be spread out very rapidly through the public transportations by the travelers with the syndrome. The challenge was to stop the <span class="hlt">SARS</span> carriers traveling around by trains, airplanes, coaches and etc. It is impractical with traditional oral thermometers or spot infrared thermometers to screen the tens of travelers with elevated body temperature from thousands of normal travelers in hours. The thermal imager with temperature measurement function is a logical choice for this special application although there are some limitations and drawbacks. This paper discusses the real <span class="hlt">SARS</span> applications of industrial infrared cameras in China from April to July 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/379507','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/379507"><span id="translatedtitle">INTA-<span class="hlt">SAR</span> real-time processor</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gomez, B.; Leon, J.</p> <p>1996-10-01</p> <p>This paper presents the INTASAR real time processor development based on a DSP open architecture for processing Synthetic Aperture Radar (<span class="hlt">SAR</span>) signal. The final designed architecture must consider three different constraints sources: (a) <span class="hlt">SAR</span> signal characteristics : high dynamic range, and complex <span class="hlt">SAR</span> imaging algorithms with high computational load (multiprocessing is convenient). (b) Flexible: in connectivity and algorithms to be programmed. (c) Suitable: for on-board and ground working. The real time constraints will be defined by the image acquisition time, within it the INTASAR system will process the rawdata image and finally presents the results in the system monitor. At ground, however, the real time processing is not a constraint, but the high quality image is. The first algorithm implemented in the system was a Range - Doppler one. With the multiprocessor architecture selected, a pipeline processing method is used. 17 refs., 4 figs., 2 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/14733734','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/14733734"><span id="translatedtitle"><span class="hlt">SARS</span>: lessons learned from other coronaviruses.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Navas-Martin, Sonia; Weiss, Susan R</p> <p>2003-01-01</p> <p>The identification of a new coronavirus as the etiological agent of severe acute respiratory syndrome (<span class="hlt">SARS</span>) has evoked much new interest in the molecular biology and pathogenesis of coronaviruses. This review summarizes present knowledge on coronavirus molecular biology and pathogenesis with particular emphasis on mouse hepatitis virus (MHV). MHV, a member of coronavirus group 2, is a natural pathogen of the mouse; MHV infection of the mouse is considered one of the best models for the study of demyelinating disease, such as multiple sclerosis, in humans. As a result of the <span class="hlt">SARS</span> epidemic, coronaviruses can now be considered as emerging pathogens. Future research on <span class="hlt">SARS</span> needs to be based on all the knowledge that coronavirologists have generated over more than 30 years of research. PMID:14733734</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790023272','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790023272"><span id="translatedtitle">Linear Approximation <span class="hlt">SAR</span> Azimuth Processing Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindquist, R. B.; Masnaghetti, R. K.; Belland, E.; Hance, H. V.; Weis, W. G.</p> <p>1979-01-01</p> <p>A segmented linear approximation of the quadratic phase function that is used to focus the synthetic antenna of a <span class="hlt">SAR</span> was studied. Ideal focusing, using a quadratic varying phase focusing function during the time radar target histories are gathered, requires a large number of complex multiplications. These can be largely eliminated by using linear approximation techniques. The result is a reduced processor size and chip count relative to ideally focussed processing and a correspondingly increased feasibility for spaceworthy implementation. A preliminary design and sizing for a spaceworthy linear approximation <span class="hlt">SAR</span> azimuth processor meeting requirements similar to those of the SEASAT-A <span class="hlt">SAR</span> was developed. The study resulted in a design with approximately 1500 IC's, 1.2 cubic feet of volume, and 350 watts of power for a single look, 4000 range cell azimuth processor with 25 meters resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920018789','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920018789"><span id="translatedtitle">Calibration of a polarimetric imaging <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sarabandi, K.; Pierce, L. E.; Ulaby, F. T.</p> <p>1991-01-01</p> <p>Calibration of polarimetric imaging Synthetic Aperture Radars (<span class="hlt">SAR</span>'s) using point calibration targets is discussed. The four-port network calibration technique is used to describe the radar error model. The polarimetric ambiguity function of the <span class="hlt">SAR</span> is then found using a single point target, namely a trihedral corner reflector. Based on this, an estimate for the backscattering coefficient of the terrain is found by a deconvolution process. A radar image taken by the JPL Airborne <span class="hlt">SAR</span> (AIRSAR) is used for verification of the deconvolution calibration method. The calibrated responses of point targets in the image are compared both with theory and the POLCAL technique. Also, response of a distributed target are compared using the deconvolution and POLCAL techniques.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20130001828&hterms=digital+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddigital%2Bcopyright','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20130001828&hterms=digital+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddigital%2Bcopyright"><span id="translatedtitle">First Results from an Airborne Ka-Band <span class="hlt">SAR</span> Using Sweep<span class="hlt">SAR</span> and Digital Beamforming</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sadowy, Gregory A.; Ghaemi, Hirad; Hensley, Scott C.</p> <p>2012-01-01</p> <p>Sweep<span class="hlt">SAR</span> is a wide-swath synthetic aperture radar technique that is being studied for application on the future Earth science radar missions. This paper describes the design of an airborne radar demonstration that simulates an 11-m L-band (1.2-1.3 GHz) reflector geometry at Ka-band (35.6 GHz) using a 40-cm reflector. The Ka-band Sweep<span class="hlt">SAR</span> Demonstration system was flown on the NASA DC-8 airborne laboratory and used to study engineering performance trades and array calibration for Sweep<span class="hlt">SAR</span> configurations. We present an instrument and experiment overview, instrument calibration and first results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1317065','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1317065"><span id="translatedtitle">Longitudinal Analysis of Severe Acute Respiratory Syndrome (<span class="hlt">SARS</span>) Coronavirus-Specific Antibody in <span class="hlt">SARS</span> Patients</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chang, Shan-Chwen; Wang, Jann-Tay; Huang, Li-Min; Chen, Yee-Chun; Fang, Chi-Tai; Sheng, Wang-Huei; Wang, Jiun-Ling; Yu, Chong-Jen; Yang, Pan-Chyr</p> <p>2005-01-01</p> <p>The serum antibodies to severe acute respiratory syndrome (<span class="hlt">SARS</span>) coronavirus of 18 <span class="hlt">SARS</span> patients were checked at 1 month and every 3 months after disease onset. All of them except one, who missed blood sampling at 1 month, tested positive for the immunoglobulin G (IgG) antibody at 1 month. Fifteen out of 17 tested positive for the IgM antibody at 1 month. The serum IgM antibody of most patients became undetectable within 6 months after the onset of <span class="hlt">SARS</span>. The IgG antibody of all 17 patients, whose serum was checked 1 year after disease onset, remained positive. PMID:16339072</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESASP.731E...7E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESASP.731E...7E"><span id="translatedtitle">Advanced In<span class="hlt">SAR</span> Processing in the Footsteps of Squee<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Even, Markus</p> <p>2015-05-01</p> <p>Several years ago a promising approach for processing In<span class="hlt">SAR</span> time series was introduced under the name Squee<span class="hlt">SAR</span> [1]. The successful application of this framework poses some delicate questions. This paper focuses on the problem that real data do rarely behave perfectly Gaussian. An augmentation of the stochastic model underlying the phase linking step is presented and the applicability under the assumption of complex elliptically symmetric distribution is discussed. Results from tests with two time series of Terra<span class="hlt">SAR</span>-X HRS data are presented and preliminary conclusions drawn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=sars&id=EJ885604','ERIC'); return false;" href="http://eric.ed.gov/?q=sars&id=EJ885604"><span id="translatedtitle">Severe Acute Respiratory Syndrome (<span class="hlt">SARS</span>) Prevention in Taiwan</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Liu, Hsueh-Erh</p> <p>2004-01-01</p> <p>Severe Acute Respiratory Syndrome (<span class="hlt">SARS</span>) is a newly identified respiratory disease that threatened Taiwan between April 14 and July 5, 2003. Chang Gung University experienced various <span class="hlt">SARS</span>-related episodes, such as the postponement of classes for 7 days, the reporting of probable <span class="hlt">SARS</span> cases, and the isolation of students under Level A and B…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..109..178B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..109..178B"><span id="translatedtitle">Mapping slope movements in Alpine environments using Terra<span class="hlt">SAR</span>-X interferometric methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barboux, Chloé; Strozzi, Tazio; Delaloye, Reynald; Wegmüller, Urs; Collet, Claude</p> <p>2015-11-01</p> <p>Mapping slope movements in Alpine environments is an increasingly important task in the context of climate change and natural hazard management. We propose the detection, mapping and inventorying of slope movements using different interferometric methods based on Terra<span class="hlt">SAR</span>-X satellite images. Differential <span class="hlt">SAR</span> interferograms (DIn<span class="hlt">SAR</span>), Persistent Scatterer Interferometry (PSI), Short-Baseline Interferometry (SBAS) and a semi-automated texture image analysis are presented and compared in order to determine their contribution for the automatic detection and mapping of slope movements of various velocity <span class="hlt">rates</span> encountered in Alpine environments. Investigations are conducted in a study region of about 6 km × 6 km located in the Western Swiss Alps using a unique large data set of 140 DIn<span class="hlt">SAR</span> scenes computed from 51 summer Terra<span class="hlt">SAR</span>-X (TSX) acquisitions from 2008 to 2012. We found that PSI is able to precisely detect only points moving with velocities below 3.5 cm/yr in the LOS, with a root mean squared error of about 0.58 cm/yr compared to DGPS records. SBAS employed with 11 days summer interferograms increases the range of detectable movements to <span class="hlt">rates</span> up to 35 cm/yr in the LOS with a root mean squared error of 6.36 cm/yr, but inaccurate measurements due to phase unwrapping are already possible for velocity <span class="hlt">rates</span> larger than 20 cm/year. With the semi-automated texture image analysis the rough estimation of the velocity <span class="hlt">rates</span> over an outlined moving zone is accurate for <span class="hlt">rates</span> of "cm/day", "dm/month" and "cm/month", but due to the decorrelation of yearly TSX interferograms this method fails for the observation of slow movements in the "cm/yr" range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcSpe.101..240B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcSpe.101..240B"><span id="translatedtitle">A simple and fast method for assessment of the nitrogen-phosphorus-potassium <span class="hlt">rating</span> of fertilizers using high-resolution continuum source atomic and molecular <span class="hlt">absorption</span> spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bechlin, Marcos André; Fortunato, Felipe Manfroi; da Silva, Ricardo Moutinho; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta</p> <p>2014-11-01</p> <p>The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular <span class="hlt">absorption</span> spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500-5000 mg L- 1 N (r = 0.9994), 100-2000 mg L- 1 P (r = 0.9946), and 100-2500 mg L- 1 K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97-105% (NO3--N), 95-103% (NH4+-N), 93-103% (urea-N), 99-108% (P), and 99-102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvB..89p5112U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvB..89p5112U"><span id="translatedtitle">Electron thermalization and trapping <span class="hlt">rates</span> in pure and doped alkali and alkaline-earth iodide crystals studied by picosecond optical <span class="hlt">absorption</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ucer, K. B.; Bizarri, G.; Burger, A.; Gektin, A.; Trefilova, L.; Williams, R. T.</p> <p>2014-04-01</p> <p>Although light continues to be emitted from insulating crystals used as scintillators over a period of nanoseconds to microseconds after stopping of an energetic particle, much of what determines the nonlinearity of response goes on in the first picoseconds. On this time scale, free carriers and excitons are at high density near the track core and thus are subject to nonlinear quenching. The hot (free) electrons eventually cool to low enough energy that trapping on holes, dopants, or defects can commence. In the track environment, spatial distributions of trapped carriers determined on the picosecond time scale can influence the proportionality between light yield and the initial particle energy throughout the whole light pulse. Picosecond spectroscopy of optical <span class="hlt">absorption</span> induced by a short pulse of above-gap excitation provides a useful window on what occurs during the crucial early evolution of excited populations. The laser excitation can be tuned to excite carriers that are initially very hot (˜3 eV) relative to the band edges, or that are almost thermalized (˜0.1 eV excess energy) at the outset. Undoped and doped samples of NaI:Tl(0%, 0.1%), CsI:Tl(0%, 0.01%, 0.04%, 0.3%), and SrI2:Eu(0%, 0.2%, 0.5%, 3%) are studied in this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25721224','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25721224"><span id="translatedtitle">Intense Upconversion Luminescence of CaSc2 O4 :Ho(3+) /Yb(3+) from Large <span class="hlt">Absorption</span> Cross Section and Energy-Transfer <span class="hlt">Rate</span> of Yb(3.).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Jing; Zhang, Jiahua; Hao, Zhendong; Chen, Li; Zhang, Xia; Luo, Yongshi</p> <p>2015-05-18</p> <p>Concentration-optimized CaSc2 O4 :0.2 % Ho(3+) /10 % Yb(3+) shows stronger upconversion luminescence (UCL) than a typical concentration-optimized upconverting phosphor Y2 O3 :0.2 % Ho(3+) /10 %  b(3+) upon excitation with a 980 nm laser diode pump. The (5) F4 +(5) S2 →(5) I8 green UCL around 545 nm and (5) F5 →(5) I8 red UCL around 660 nm of Ho(3+) are enhanced by factors of 2.6 and 1.6, respectively. On analyzing the emission spectra and decay curves of Yb(3+) : (2) F5/2 →(2) F7/2 and Ho(3+) : (5) I6 →(5) I8 , respectively, in the two hosts, we reveal that Yb(3+) in CaSc2 O4 exhibits a larger <span class="hlt">absorption</span> cross section at 980 nm and subsequent larger Yb(3+) : (2) F5/2 →Ho(3+) : (5) I6 energy-transfer coefficient (8.55×10(-17) cm(3) s(-1) ) compared to that (4.63×10(-17) cm(3) s(-1) ) in Y2 O3 , indicating that CaSc2 O4 :Ho(3+) /Yb(3+) is an excellent oxide upconverting material for achieving intense UCL. PMID:25721224</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5886..226G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5886..226G"><span id="translatedtitle">Does <span class="hlt">absorption</span> of ultraviolet B by stratospheric ozone and urban aerosols influence colon and breast cancer mortality <span class="hlt">rates</span>? Contributions from NASA and NOAA data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorham, Edward D.; Garland, Frank C.; Mohr, Sharif B.; Grant, William B.; Garland, Cedric F.</p> <p>2005-08-01</p> <p>Although most ultraviolet B (UVB) radiation is absorbed by stratospheric ozone, dense anthropogenic sulfate aerosols in the troposphere may further attenuate UVB in some regions. Mortality <span class="hlt">rates</span> from colon and breast cancer tend to be much higher in areas with low levels of UVB radiation. These high <span class="hlt">rates</span> may be due in part to inadequate cutaneous photosynthesis of vitamin D. Satellite data on atmospheric aerosols, stratospheric ozone, and cloud cover were obtained from the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). These data were combined with age-adjusted mortality <span class="hlt">rates</span> from 175 countries reporting to the World Health Organization. Regression was used to assess the relationship of stratospheric ozone thickness, aerosol optical depth, cloud cover, solar UVB irradiance at the top of the atmosphere, average skin exposure, and a dietary factor with colon and breast cancer mortality <span class="hlt">rates</span>. Solar UVB irradiance at the top of the atmosphere, total cloud cover, and atmospheric aerosols had the strongest associations with mortality <span class="hlt">rates</span>, apart from a strong influence of diet. Since 95% of circulating vitamin D is derived from current or stored products of photosynthesis, which may be nonexistent or minimal much of the year above 37°N or below 37°S, attenuation of UVB by atmospheric aerosols and clouds may have a greater than expected adverse effect on human health.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPA....6g5202M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPA....6g5202M"><span id="translatedtitle">On the optimization, and the intensity dependence, of the excitation <span class="hlt">rate</span> for the <span class="hlt">absorption</span> of two-photons due to the direct permanent dipole moment excitation mechanism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meath, William J.</p> <p>2016-07-01</p> <p>A model two-level dipolar molecule, and the rotating wave approximation and perturbation theory, are used to investigate the optimization and the laser intensity dependence of the two-photon excitation <span class="hlt">rate</span> via the direct permanent dipole mechanism. The <span class="hlt">rate</span> is proportional to the square of the laser intensity I only for small intensities and times when perturbation theory is applicable. An improvement on perturbation theory is provided by a small time RWA result for the <span class="hlt">rate</span> which is not proportional to I2; rather it is proportional to the square of an effective intensity Ieff. For each laser intensity the optimum RWA excitation <span class="hlt">rate</span> as a function of time, for low intensities, is proportional to I, not I2, and for high intensities it is proportional to Ieff. For a given two-photon transition the laser-molecule coupling optimizes for an intensity Imax which, for example, leads to a maximum possible excitation <span class="hlt">rate</span> as a function of time. The validity of the RWA results of this paper, and the importance of including the effects of virtual excited states, are also discussed briefly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.G31D..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.G31D..03C"><span id="translatedtitle">Creep Along the North Anatolian Fault at Ismetpasa (Western Turkey) Deduced From In<span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cakir, Z.; Ergintav, S.; Akoglu, A. M.; Belabbes, S.; Meghraoui, M.</p> <p>2004-12-01</p> <p>Although creeping along the North Anatolian Fault (NAF) at Ismetpasa (Turkey) was discovered some thirty years ago, about a decade after the first observation of the phenomenon along the San Andreas Fault in California, little is known about its extent and <span class="hlt">rate</span>. In order to reveal its three dimensional nature and rupture characteristics, we use Synthetic Aperture Radar Interferometry (In<span class="hlt">SAR</span>) and dislocations on rectangular faults in elastic half space. Interferograms with temporal baselines ranging between 1.25 and 5 years show that creeping starts at the western termination of the 1943 (Mw=7.6) earthquake rupture and continues about 70-km to the west overlapping with the eastern part of the 185-km-long rupture of the 1944 (Mw=7.3) earthquake. Maximum creep <span class="hlt">rate</span> is 10 mm/year approximately in the mid point of the creeping part of the rupture segment diminishing gradually towards the edges. Near Ismetpasa, In<span class="hlt">SAR</span> data yield 7.7 mm/year of creep <span class="hlt">rate</span>, consistent with those deduced from instrumental (triangulation and creepmeters) measurements (i.e. 9 mm/year). Modeling of the In<span class="hlt">SAR</span> and GPS data suggests that the fault creep occurs most probably at a shallow depth (0-7 km). In<span class="hlt">SAR</span> data do not support the previous claims of creep events triggered by the 1999 Izmit earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E3199H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E3199H"><span id="translatedtitle">A tool for bistatic <span class="hlt">sar</span> geometry determinations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hawkins, R.; Gibson, J.; Antonik, P.; Saper, R.; Seymour, M.; St Hilaire, M.; Livingstone, C.</p> <p></p> <p>The geometry of wide angle bistatic <span class="hlt">SAR</span> is somewhat more complex than that of conventional <span class="hlt">SAR</span> because the transmitter and receiver are displaced considerably. Constant bistatic range contours projected onto the geoid form ellipse-like profiles with the transmitter and receiver located at the two foci. Constant Doppler lines intersect the range ellipses and allow under special circumstances a simple orthogonal basis for processing and analysis. This paper illustrates a simple GUI- based tool developed in a MatLab that uses satellite orbit parameters and RADARSAT-1 data to simulate the bistatic geometry and scattering for a tower- based receiver.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994SPIE.2316..192F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994SPIE.2316..192F"><span id="translatedtitle"><span class="hlt">SAR</span> simulation of three-dimensional scenes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Franceschetti, Giorgio; Marino, Raimundo; Migliaccio, Maurizio; Riccio, Daniele</p> <p>1994-12-01</p> <p>In this paper we examine the <span class="hlt">SAR</span> raw signal simulation of extended mountainous natural terrain. In order to cope with this goal we need to consider some problems relative to the evaluation of the backscattering pattern and of the efficient and correct inclusion of the <span class="hlt">SAR</span> system unit response. In particular, and with regard to the first issue inclusion of the third dimension requires accommodation of its coarse description. Subjective and objective norms in order to judge the simulation results are presented and discussed, together with a number of examples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.5095....9G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.5095....9G"><span id="translatedtitle">FOPEN ultrawideband <span class="hlt">SAR</span> imaging by wavelet interpolation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Hanwei; Liang, Diannong; Wang, Yan; Huang, Xiaotao; Dong, Zhen</p> <p>2003-09-01</p> <p>Wave number Domain Imaging algorithm can deal with the problem of foliage-penetrating ultra-wide band synthesis aperture radar (FOPEN UWB <span class="hlt">SAR</span>) imaging. Stolt interpolation is a key role in Imaging Algorithm and is unevenly interpolation problem. There is no fast computation algorithm on Stolt interpolation. In this paper, A novel 4-4 tap of integer wavelet filters is used as Stolt interpolation base function. A fast interpolation algorithm is put forwards to. There is only plus and shift operation in wavelet interpolation that is easy to realize by hardware. The real data are processed to prove the wavelet interpolation valid for FOPEN UWB <span class="hlt">SAR</span> imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780028753&hterms=Beam-pointing+error&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeam-pointing%2Berror','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780028753&hterms=Beam-pointing+error&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeam-pointing%2Berror"><span id="translatedtitle">CCD architecture for spacecraft <span class="hlt">SAR</span> image processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Arens, W. E.</p> <p>1977-01-01</p> <p>A real-time synthetic aperture radar (<span class="hlt">SAR</span>) image processing architecture amenable to future on-board spacecraft applications is currently under development. Using state-of-the-art charge-coupled device (CCD) technology, low cost and power are inherent features. Other characteristics include the ability to reprogram correlation reference functions, correct for range migration, and compensate for antenna beam pointing errors on the spacecraft in real time. The first spaceborne demonstration is scheduled to be flown as an experiment on a 1982 Shuttle imaging radar mission (SIR-B). This paper describes the architecture and implementation characteristics of this initial spaceborne CCD <span class="hlt">SAR</span> image processor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940000371&hterms=Base+data+multidimensional&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBase%2Bdata%2Bmultidimensional','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940000371&hterms=Base+data+multidimensional&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBase%2Bdata%2Bmultidimensional"><span id="translatedtitle">Unsupervised Segmentation Of Polarimetric <span class="hlt">SAR</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rignot, Eric J.; Dubois, Pascale; Van Zyl, Jakob; Kwok, Ronald; Chellappa, Rama</p> <p>1994-01-01</p> <p>Method of unsupervised segmentation of polarimetric synthetic-aperture-radar (<span class="hlt">SAR</span>) image data into classes involves selection of classes on basis of multidimensional fuzzy clustering of logarithms of parameters of polarimetric covariance matrix. Data in each class represent parts of image wherein polarimetric <span class="hlt">SAR</span> backscattering characteristics of terrain regarded as homogeneous. Desirable to have each class represent type of terrain, sea ice, or ocean surface distinguishable from other types via backscattering characteristics. Unsupervised classification does not require training areas, is nearly automated computerized process, and provides nonsubjective selection of image classes naturally well separated by radar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/952099','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/952099"><span id="translatedtitle">Estimating IMU heading error from <span class="hlt">SAR</span> images.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Doerry, Armin Walter</p> <p>2009-03-01</p> <p>Angular orientation errors of the real antenna for Synthetic Aperture Radar (<span class="hlt">SAR</span>) will manifest as undesired illumination gradients in <span class="hlt">SAR</span> images. These gradients can be measured, and the pointing error can be calculated. This can be done for single images, but done more robustly using multi-image methods. Several methods are provided in this report. The pointing error can then be fed back to the navigation Kalman filter to correct for problematic heading (yaw) error drift. This can mitigate the need for uncomfortable and undesired IMU alignment maneuvers such as S-turns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JESS..tmp...92C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JESS..tmp...92C"><span id="translatedtitle">Detecting, mapping and monitoring of land subsidence in Jharia Coalfield, Jharkhand, India by spaceborne differential interferometric <span class="hlt">SAR</span>, GPS and precision levelling techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chatterjee, R. S.; Thapa, Shailaja; Singh, K. B.; Varunakumar, G.; Raju, E. V. R.</p> <p>2015-08-01</p> <p>The study aims at detection, mapping and monitoring of land subsidence in Jharia Coalfield, Jharkhand, India by spaceborne DIn<span class="hlt">SAR</span>, GPS and precision levelling techniques. Using multi-frequency C- and L-band DIn<span class="hlt">SAR</span>, both slowly and rapidly subsiding areas were identified and DIn<span class="hlt">SAR</span>-based subsidence maps were prepared. C-band DIn<span class="hlt">SAR</span> was found useful for detection of slowly subsiding areas whereas L-band DIn<span class="hlt">SAR</span> for rapidly subsiding and/or adverse land cover areas. Due to dynamic nature of mining and adverse land cover, temporal decorrelation poses a serious problem particularly in C-band DIn<span class="hlt">SAR</span>. Specially designed In<span class="hlt">SAR</span> coherence guided adaptive filtering was found useful to highlight the deformation fringes. Collateral GPS and levelling observations were conducted in three test sites to validate DIn<span class="hlt">SAR</span> measurements and to determine the net displacement vectors. We observed an appreciable horizontal displacement component of land subsidence in all the test sites. For comparison of results, we calculated In<span class="hlt">SAR</span> coherence weighted LOS displacement <span class="hlt">rates</span> from the unwrapped differential interferograms of smaller spatial subsets and LOS projected ground-based displacement <span class="hlt">rates</span> in three test sites. We found good agreement between DIn<span class="hlt">SAR</span> and ground-based measurements except for C-band observation in Dobari test site primarily due to large difference in observation periods and temporally inconsistent land subsidence. Collateral spaceborne and ground-based observations were also found useful for characterization of subsidence phenomena to determine net displacement vector and horizontal displacement component. In coal mining areas with spatially scattered and temporally irregular land subsidence phenomena, the adopted methodology can be used successfully for detection, mapping and monitoring of the subsiding areas vulnerable to future collapse. This will facilitate efficient planning and designing of surface infrastructures and other developmental structures in the mining</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/1789123','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/1789123"><span id="translatedtitle">133Xenon <span class="hlt">absorption</span> into rubber-protected portable cadmium telluride (CdTe(Cl)) detectors invalidating the 133Xenon washout method for measurement of cutaneous and subcutaneous blood flow <span class="hlt">rates</span> in man.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sørensen, J L</p> <p>1991-01-01</p> <p>The importance of 133Xenon <span class="hlt">absorption</span> into rubber detector caps during cutaneous and subcutaneous blood flow measurement was investigated in 46 experiments involving 38 persons. 133Xenon was administered atraumatically. Cutaneous and subcutaneous washout <span class="hlt">rates</span> were registered by portable Cadmium Telluride detectors without rubber caps, with rubber caps, and with rubber caps with Mylar membranes interposed between the rubber and the tissue investigated. No difference in <span class="hlt">rate</span> constants obtained by means of various detector types was detected. The accumulation of 133Xenon in the rubber caps was found to take place within the first few minutes after the detectors had been brought into position. The 133Xenon then diffused back into the tissue exhibiting a great variation regarding <span class="hlt">rate</span> constants. The 133Xenon diffused form rubber into air and perfused tissue tracing a monoexponential course; and again the <span class="hlt">rate</span> constants would vary considerably. No correlation was found between elimination <span class="hlt">rates</span> obtained with detectors with and without 133Xenon polluted caps, and no way of correcting for the 133Xenon content in the rubber caps was found. Relative changes in <span class="hlt">rate</span> constants could still be recognized, but absolute values were not obtainable. PMID:1789123</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013DPS....4521116E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013DPS....4521116E&link_type=ABSTRACT"><span id="translatedtitle">Mars Mission Concepts: <span class="hlt">SAR</span> and Solar Electric Propulsion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elsperman, Michael; Clifford, S.; Lawrence, S.; Klaus, K.; Smith, D.</p> <p>2013-10-01</p> <p>Introduction: The time has come to leverage technology advances to reduce the cost and increase the flight <span class="hlt">rate</span> of planetary missions, while actively developing a scientific and engineering workforce to achieve national space objectives. Mission Science at Mars: A <span class="hlt">SAR</span> imaging radar offers an ability to conduct high resolution investigations of the shallow subsurface of Mars, enabling identification of fine-scale layering within the Martian polar layered deposits (PLD), as well as the identification of pingos, investigations of polygonal terrain, and measurements of the thickness of mantling layers at non-polar latitudes. It would allow systematic near-surface prospecting, which is tremendously useful for human exploration purposes. Limited color capabilities in a notional high-resolution stereo imaging system would enable the generation of false color images, resulting in useful science results, and the stereo data could be reduced into high-resolution Digital Elevation Models uniquely useful for exploration planning and science purposes. Mission Concept: Using a common spacecraft for multiple missions reduces costs. Solar electric propulsion (SEP) provides the flexibility required for multiple mission objectives. Our concept involves using a Boeing 702SP with a highly capable <span class="hlt">SAR</span> imager that also conducts autonomous rendezvous and docking experiments accomplished from Mars orbit. Summary/Conclusions: A robust and compelling Mars mission can be designed to meet the 2018 Mars launch window opportunity. Using advanced in-space power and propulsion technologies like High Power Solar Electric Propulsion provides enormous mission flexibility to execute the baseline science mission and conduct necessary Mars Sample Return Technology Demonstrations in Mars orbit on the same mission. An observation spacecraft platform like the high power 5Kw) 702SP at Mars also enables the use of a <span class="hlt">SAR</span> instrument to reveal new insights and understanding of the Mars regolith for both</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.710D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.710D"><span id="translatedtitle">Validation of Open-Sea CRYOSAT-2 Data in <span class="hlt">SAR</span> Mode in the German Bight</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dinardo, Salvatore; Benveniste, Jérôme; Fenoglio-Marc, Luciana; Scharroo, Remko</p> <p></p> <p>This work aims to generate and validate the altimetric geophysical parameters measured by the CryoSat-2 in <span class="hlt">SAR</span> Mode in the temporal interval 2011-2012 in the area of the German Bight at distance to coast larger than 10 Kilometers (open-sea). Instantaneous sea surface height (SSH), significant wave height (SWH) and wind speed at 10 meter from sea surface (U10), measured by CryoSat-2, are compared to in-situ measurements at platforms, buoys and tide gauges and to results from an operational circulation model run by the German Federal Maritime and Hydrographic Agency (BSH). The in-situ data were made available by the Wasser- und Schifffahrtsverwaltung des Bundes (WSV). These stations are part of a network of tide gauges and offshore platforms equipped with continuously operation Global Navigation Satellite System (GNSS) receivers. Since the coordinates of the zero point of the tide gauge are computed in the International Terrestrial Reference Frame (ITRF) the absolute comparison between sea level from tide gauge and altimetry is possible. The relevant in-situ data are sea level, wave and wind data. The CryoSat-2 Data have been Delay-Doppler processed as from the FBR (Full Bit <span class="hlt">Rate</span>) Level 1A to Level 1B and subsequently re-tracked using the SAMOSA's <span class="hlt">SAR</span> Echo Model (full solution) and a curve-fitting scheme based on Levenberg-Marquard Least Square Minimization Algorithm. Sea surface height, significant wave height and wind speed at 20 Hz and 1 Hz have been derived. The Delay-Doppler processing (L1B) and the re-tracking processing (L2) has been carried out by the EOP-SER Altimetry Team at ESA/ESRIN. Pseudo pulse-limited (PLRM) data derived from CryoSat-2 in <span class="hlt">SAR</span> mode and provided via the RADS database are compared with the same parameters derived from the CryoSat-2 <span class="hlt">SAR</span> Data to estimate possible biases and trends between <span class="hlt">SAR</span> mode and LRM mode and tune-up the <span class="hlt">SAR</span> re-tracking scheme. Special attention will be paid to spot trends between <span class="hlt">SAR</span> and PLRM with respect the orbital</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMEP31A0833T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMEP31A0833T"><span id="translatedtitle">Sinking Chao Phraya delta plain, Thailand, derived from <span class="hlt">SAR</span> interferometry time series analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanaka, A.; Mio, A.; Saito, Y.</p> <p>2013-12-01</p> <p>The Bangkok Metropolitan region and its surrounding provinces are located in a low-lying delta plain of the Chao Phraya River. Extensive groundwater use from the late 1950s has caused the decline of groundwater levels in the aquifers and Holocene clay compaction beneath the Bangkok Region, resulting in significant subsidence of the ground. This ground deformation has been monitored using leveling surveys since 1978, and differential In<span class="hlt">SAR</span> (Interferometric Synthetic Aperture Radar) analysis. It shows that the Bangkok Metropolitan region is subsiding at a <span class="hlt">rate</span> of about 20 mm/year during the recent years due to law-limited groundwater pumping, although the highest subsidence <span class="hlt">rate</span> as high as 120 mm/year was recorded in 1981. The subsidence <span class="hlt">rate</span> in the Bangkok area has significantly decreased since the late 1980s; however, the affected area has spread out to the surrounding areas. The maximum subsidence <span class="hlt">rate</span> up to 30 mm/year occurred in the outlying southeast and southwest coastal zones in 2002. In this study, we apply a <span class="hlt">SAR</span> interferometry time series analysis to monitor ground deformations in the lower Chao Phraya delta plain (Lower Central Plain), Thailand, using ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band <span class="hlt">SAR</span>) data acquired between July 2007 and September 2010. We derive a single reference time series interferogram from the stacking of unwrapped phases under the assumptions that those phases are smoothly and continuously connected, and apply a smoothness-constrained inversion algorithm that optimizes the displacement from the phase unwrapping of multitemporal differential <span class="hlt">SAR</span> interferograms. The <span class="hlt">SAR</span> interferometry time series analysis succeeds to monitor the incremental line-of-sight (LOS)-change between <span class="hlt">SAR</span> scene acquisitions. LOS displacements are converted to vertical displacements, based on the assumption that the ground displacement in this area occurs only in the vertical directions. This reveals an overall pattern of subsidence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1000734','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1000734"><span id="translatedtitle">Performance of a four-element Si drift detector for X-ray <span class="hlt">absorption</span> fine-structure spectroscopy: resolution, maximum count <span class="hlt">rate</span>, and dead-time correction with incorporation into the ATHENA data analysis software</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Woicik, J.C.; Newburgh, W.; Ravel, B.; Fischer, D.A.</p> <p>2010-03-09</p> <p>The performance of a four-element Si drift detector for energy-dispersive fluorescence-yield X-ray <span class="hlt">absorption</span> fine-structure measurements is reported, operating at the National Institute of Standards and Technology beamline X23A2 at the National Synchrotron Light Source. The detector can acquire X-ray <span class="hlt">absorption</span> fine-structure spectra with a throughput exceeding 4 x 10{sup 5} counts per second per detector element (>1.6 x 10{sup 6} total counts per second summed over all four channels). At this count <span class="hlt">rate</span> the resolution at 6 keV is approximately 220 eV, which adequately resolves the Mn K{sub {alpha}} and K{sup {beta}} fluorescence lines. Accurate dead-time correction is demonstrated, and it has been incorporated into the ATHENA data analysis program. To maintain counting efficiency and high signal to background, it is suggested that the incoming count <span class="hlt">rate</span> should not exceed {approx}70% of the maximum throughput.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19399244','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19399244"><span id="translatedtitle">Quantum-<span class="hlt">SAR</span> extension of the spectral-<span class="hlt">SAR</span> algorithm: application to polyphenolic anticancer bioactivity.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Putz, Mihai V; Putz, Ana-Maria; Lazea, Marius; Ienciu, Luciana; Chiriac, Adrian</p> <p>2009-03-01</p> <p>Aiming to assess the role of individual molecular structures in the molecular mechanism of ligand-receptor interaction correlation analysis, the recent Spectral-<span class="hlt">SAR</span> approach is employed to introduce the Quantum-<span class="hlt">SAR</span> (Qua<span class="hlt">SAR</span>) "wave" and "conversion factor" in terms of difference between inter-endpoint inter-molecular activities for a given set of compounds; this may account for inter-conversion (metabolization) of molecular (concentration) effects while indicating the structural (quantum) based influential/detrimental role on bio-/eco- effect in a causal manner rather than by simple inspection of measured values; the introduced Qua<span class="hlt">SAR</span> method is then illustrated for a study of the activity of a series of flavonoids on breast cancer resistance protein. PMID:19399244</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=294579','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=294579"><span id="translatedtitle">Diminished virulence of a <span class="hlt">sar</span>-/agr- mutant of Staphylococcus aureus in the rabbit model of endocarditis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cheung, A L; Eberhardt, K J; Chung, E; Yeaman, M R; Sullam, P M; Ramos, M; Bayer, A S</p> <p>1994-01-01</p> <p>Microbial pathogenicity in Staphylococcus aureus is a complex process involving a number of virulence genes that are regulated by global regulatory systems including <span class="hlt">sar</span> and agr. To evaluate the roles of these two loci in virulence, we constructed <span class="hlt">sar</span>-/agr- mutants of strains RN6390 and RN450 and compared their phenotypic profiles to the corresponding single <span class="hlt">sar</span>- and agr- mutants and parents. The secretion of all hemolysins was absent in the <span class="hlt">sar</span>-/agr- mutants while residual beta-hemolysin activity remained in single agr- mutants. The fibronectin binding capacity was significantly diminished in both single <span class="hlt">sar</span>- mutants and double mutants when compared with parents while the reduction in fibrinogen binding capacity in the double mutants was modest. In the rabbit endocarditis model, there was a significant decrease in both infectivity <span class="hlt">rates</span> and intravegetation bacterial densities with the double mutant as compared to the parent (RN6390) at 10(3)-10(6) CFU inocula despite comparable levels of early bacteremia among various challenge groups. Notably, fewer bacteria in the double mutant group adhered to valvular vegetations at 30 min after challenge (10(6) CFU) than the parent group. These studies suggest that both the <span class="hlt">sar</span> and agr loci are involved in initial valvular adherence, intravegetation persistence and multiplication of S. aureus in endocarditis. Images PMID:7962526</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000052471','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000052471"><span id="translatedtitle">The "Myth" of the Minimum <span class="hlt">SAR</span> Antenna Area Constraint</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, A.; Johnson, W. T. K.; Huneycutt, B.; Jordan, R.; Hensley, S.; Siqueira, P.; Curlander, J.</p> <p>1998-01-01</p> <p>A design constraint traceable ot the early days of spaceborne Synthetic Aperture Radar (<span class="hlt">SAR</span>) is known as the minimum antenna area constraint for <span class="hlt">SAR</span>. In this paper, it is confirmed that this constraint strictly applies only to the case where both the best possible resolution and the widest possible swath are the design goals. <span class="hlt">SAR</span> antennas with area smaller than the constraint allows are shown to be possible, have been used on spaceborne <span class="hlt">SAR</span> missions in the past, and should permit further, lower-cost <span class="hlt">SAR</span> mission in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24138240','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24138240"><span id="translatedtitle">Chaotic systems with <span class="hlt">absorption</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Altmann, Eduardo G; Portela, Jefferson S E; Tél, Tamás</p> <p>2013-10-01</p> <p>Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe <span class="hlt">absorption</span> in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape <span class="hlt">rate</span> κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions D(q) obtained without taking <span class="hlt">absorption</span> and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D(1) in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection <span class="hlt">rate</span>. Simulations in the cardioid billiard confirm these results. PMID:24138240</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4985B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4985B"><span id="translatedtitle">Cryosat-2 <span class="hlt">SAR</span> and <span class="hlt">SAR</span>-In Altimetry for Coastal Sea Level</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baltazar Andersen, Ole; Knudsen, Per; Abulaitijiang, Adil; Stenseng, Lars</p> <p>2015-04-01</p> <p>Cryosat-2 offers the first ever possibility to perform coastal altimetric studies using <span class="hlt">SAR</span>-Interferometry as well as <span class="hlt">SAR</span> altimetry. With this technological leap forward Cryosat-2 is now able to observe sea level in very small water bodies and also to provide coastal sea level very close to the shore. We perform an investigation into the retrieval of sea surface height around Denmark and Greenland. These regions have been chosen as the coastal regions around Denmark falls within the <span class="hlt">SAR</span> mask and the coastal regions of Greenland falls in under the <span class="hlt">SAR</span>-in mask employed on Cryosat-2. <span class="hlt">SAR</span>-in was mainly used in coastal regions of Greenland because of its huge topographic changes as Cryosat-2 is designed to map the margins of the ice-sheet. The coastal region around Denmark is a test region of the EU sponsored project LOTUS in which With the increased spatial resolution of Cryosat-2 <span class="hlt">SAR</span> we provide valuable sea level observations within the Straits around Denmark which are crucial to constrain the waterflow in and out of the Baltic Sea. The investigation of <span class="hlt">SAR</span>-in data in Greenland adds an entire new dimension to coastal altimetry. An amazing result of the investigation is the ability of Cryosat-2 to detect and recover sea level even though the coast (sealevel) is up to 15 km away from the nadir location of the satellite. This ability of capture and use returns from outside the main (-3Db) loop in theory enables Cryosat-2 <span class="hlt">SAR</span>-in to map sea level height of fjords more frequently than the 369 days repeat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/634093','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/634093"><span id="translatedtitle">Very low <span class="hlt">rate</span> compression of speckled <span class="hlt">SAR</span> imagery</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eichel, P.H.; Ives, R.W.</p> <p>1998-01-01</p> <p>Synthetic aperture radars produce coherent, and speckled, high resolution images of the ground. Because modern systems can generate large amounts of imagery, there is substantial interest in applying image compression techniques to these products. In this paper, the authors examine the properties of speckled imagery relevant to the task of data compression. In particular, they demonstrate the advisability of compressing the speckle mean function rather than the literal image. The theory, methodology, and an example are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=%22infectious+diseases%22+NOT+%22virus+diseases%22&pg=3&id=EJ900047','ERIC'); return false;" href="http://eric.ed.gov/?q=%22infectious+diseases%22+NOT+%22virus+diseases%22&pg=3&id=EJ900047"><span id="translatedtitle">Epidemic Models for <span class="hlt">SARS</span> and Measles</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Rozema, Edward</p> <p>2007-01-01</p> <p>Recent events have led to an increased interest in emerging infectious diseases. This article applies various deterministic models to the <span class="hlt">SARS</span> epidemic of 2003 and a measles outbreak in the Netherlands in 1999-2000. We take a historical approach beginning with the well-known logistic curve and a lesser-known extension popularized by Pearl and Reed…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920000275&hterms=optical+electronics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Doptical%2Belectronics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920000275&hterms=optical+electronics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Doptical%2Belectronics"><span id="translatedtitle">Acousto-Optical/Electronic Processor For <span class="hlt">SAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bicknell, T. J.; Farr, W. H.</p> <p>1992-01-01</p> <p>Lightweight, compact, low-power apparatus processes synthetic-aperture-radar (<span class="hlt">SAR</span>) returns in real time, providing imagery aboard moving aircraft or spacecraft platform. Processor includes optical and electronic subsystems that, together, resolve range and azimuth coordinates of radar targets by combination of spatial and temporal integrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2263793','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2263793"><span id="translatedtitle"><span class="hlt">SARS</span>: An Emerging Global Microbial Threat.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hughes, James M.</p> <p>2004-01-01</p> <p>In March 2003, the Institute of Medicine published an update to its 1992 landmark report on emerging infections. The new report, Microbial Threats to Health: Emergence, Detection, and Response, describes the current spectrum of global microbial threats, factors affecting their emergence or resurgence, and measures that should be undertaken to effectively address them. Coincident with this publication came increasing reports of severe atypical pneumonia of unknown etiology among persons in southeast Asia. This new disease, designated severe acute respiratory syndrome (<span class="hlt">SARS</span>), spread globally in a matter of weeks, infecting primarily close contacts of index patients (e.g., household members and healthcare workers caring for index patients) but also resulting in community transmission in some areas. An unprecedented worldwide collaborative effort was undertaken to determine the cause of the illness and implement prevention measures. A previously unrecognized coronavirus was identified as the causative agent, and health officials throughout the world struggled to implement measures to contain its spread, including isolation of suspect <span class="hlt">SARS</span> cases and quarantine of exposed persons. The emergence of <span class="hlt">SARS</span> is a timely reminder of the need to expect the unexpected and to ensure strong national and global public health partnerships when preparing for and responding to infectious diseases. Effectively addressing the threat of <span class="hlt">SARS</span> will require enhanced global infectious disease surveillance, the development of rapid diagnostics, new therapies, and vaccines, implementation of aggressive evidence-based infection control strategies, and effective communication. Images Fig. 2 Fig. 3 PMID:17060979</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9811E..1CT&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9811E..1CT&link_type=ABSTRACT"><span id="translatedtitle">Ambiguity noise analysis of a <span class="hlt">SAR</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tian, Haishan; Chang, Wenge; Li, Xiangyang</p> <p>2015-12-01</p> <p>The presence of range and azimuth (or Doppler) ambiguities in synthetic aperture radars (<span class="hlt">SARs</span>) is well known. The ambiguity noise is related to the antenna pattern and the value of pulse repetition frequency (PRF). Because a new frequency modulated continuous wave (FMCW) <span class="hlt">SAR</span> has the characters of low cost and small size, and the capacity of real-time signal processing, the antenna will likely vibrate or deform due to a lack of the stabilized platform. And the value of PRF cannot be much high because of the high computation burden for the real-time processing. The aim of this study is to access and improve the performance of a new FMCW <span class="hlt">SAR</span> system based on the ambiguity noise. First, the quantitative analysis of the system's ambiguity noise level is performed; an antenna with low sidelobes is designed. The conclusion is that the range ambiguity noise is small; the azimuth ambiguity noise is somewhat increased, however, it is sufficiently small to have marginal influence on the image quality. Finally, the ambiguity noise level is measured using the imaging data from a Ku-band FMCW <span class="hlt">SAR</span>. The results of this study show that the measured noise level coincides with the theoretical noise level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1002639','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1002639"><span id="translatedtitle">Discovery and <span class="hlt">SAR</span> of hydantoin TACE inhibitors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, Wensheng; Guo, Zhuyan; Orth, Peter; Madison, Vincent; Chen, Lei; Dai, Chaoyang; Feltz, Robert J.; Girijavallabhan, Vinay M.; Kim, Seong Heon; Kozlowski, Joseph A.; Lavey, Brian J.; Li, Dansu; Lundell, Daniel; Niu, Xiaoda; Piwinski, John J.; Popovici-Muller, Janeta; Rizvi, Razia; Rosner, Kristin E.; Shankar, Bandarpalle B.; Shih, Neng-Yang; Siddiqui, M.A.; Sun, J.; Tong, L.; Umland, S.; Wong, M.K.; Yang, D.Y.; Zhou, G.</p> <p>2010-09-03</p> <p>We disclose inhibitors of TNF-{alpha} converting enzyme (TACE) designed around a hydantoin zinc binding moiety. Crystal structures of inhibitors bound to TACE revealed monodentate coordination of the hydantoin to the zinc. <span class="hlt">SAR</span>, X-ray, and modeling designs are described. To our knowledge, these are the first reported X-ray structures of TACE with a hydantoin zinc ligand.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.G31A0401B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.G31A0401B"><span id="translatedtitle">The Seamless <span class="hlt">SAR</span> Archive (SSARA) Project and Other <span class="hlt">SAR</span> Activities at UNAVCO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, S.; Crosby, C. J.; Meertens, C. M.; Fielding, E. J.; Bryson, G.; Buechler, B.; Nicoll, J.; Baru, C.</p> <p>2014-12-01</p> <p>The seamless synthetic aperture radar archive (SSARA) implements a seamless distributed access system for <span class="hlt">SAR</span> data and derived data products (i.e. interferograms). SSARA provides a unified application programming interface (API) for <span class="hlt">SAR</span> data search and results at the Alaska Satellite Facility and UNAVCO (WIn<span class="hlt">SAR</span> and EarthScope data archives) through the use of simple web services. A federated query service was developed using the unified APIs, providing users a single search interface for both archives. Interest from the international community has prompted an effort to incorporate ESA's Virtual Archive 4 Geohazard Supersites and Natural Laboratories (GSNL) collections and other archives into the federated query service. SSARA also provides Digital Elevation Model access for topographic correction via a simple web service through OpenTopography and tropospheric correction products through JPL's OSCAR service. Additionally, UNAVCO provides data storage capabilities for WIn<span class="hlt">SAR</span> PIs with approved Terra<span class="hlt">SAR</span>-X and ALOS-2 proposals which allows easier distribution to US collaborators on associated proposals and facilitates data access through the SSARA web services. Further work is underway to incorporate federated data discovery for GSNL across <span class="hlt">SAR</span>, GPS, and seismic datasets provided by web services from SSARA, GSAC, and COOPEUS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830037812&hterms=aes+algorithm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Daes%2Balgorithm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830037812&hterms=aes+algorithm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Daes%2Balgorithm"><span id="translatedtitle">Modeling and a correlation algorithm for spaceborne <span class="hlt">SAR</span> signals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wu, C.; Liu, K. Y.; Jin, M.</p> <p>1982-01-01</p> <p>A mathematical model of a spaceborne synthetic aperture radar (<span class="hlt">SAR</span>) response is presented. Thhe associated <span class="hlt">SAR</span> system performance, in terms of the resolution capability, is also discussed. The analysis of spaceborne <span class="hlt">SAR</span> target response indicates that the <span class="hlt">SAR</span> correlation problem is a two-dimensional one with a linear shift-variant response function. A new digital processing algorithm is proposed here in order to realize an economical digital <span class="hlt">SAR</span> correlation system. The proposed algorithm treats the two-dimensional correlation by a combination of frequency domain fast correlation in the azimuth dimension and a time-domain convolver type of operation in the range dimension. Finally, digitally correlated SEASAT satellite <span class="hlt">SAR</span> imagery is used in an exemplary sense to validate the <span class="hlt">SAR</span> response model and the new digital processing technique developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70164312','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70164312"><span id="translatedtitle">Post-eruptive inflation of Okmok Volcano, Alaska, from In<span class="hlt">SAR</span>, 2008–2014</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Qu, Feifei; Lu, Zhong; Poland, Michael; Freymueller, Jeffrey T.; Zhang, Qin; Jung, Hyung-Sup</p> <p>2016-01-01</p> <p>Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (<span class="hlt">SAR</span>) images of Okmok acquired during that time period using the multi-temporal In<span class="hlt">SAR</span> technique. Data from the C-band Envisat and X-band Terra<span class="hlt">SAR</span>-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable <span class="hlt">rate</span> of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The In<span class="hlt">SAR</span> time-series is used as input for deformation source modeling, which suggests magma accumulating at variable <span class="hlt">rates</span> in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3705468','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3705468"><span id="translatedtitle">Detecting Land Subsidence in Shanghai by PS-Networking <span class="hlt">SAR</span> Interferometry</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Guoxiang; Luo, Xiaojun; Chen, Qiang; Huang, Dingfa; Ding, Xiaoli</p> <p>2008-01-01</p> <p>Existing studies have shown that satellite synthetic aperture radar (<span class="hlt">SAR</span>) interferometry has two apparent drawbacks, i.e., temporal decorrelation and atmospheric contamination, in the application of deformation mapping. It is however possible to improve deformation analysis by tracking some natural or man-made objects with steady radar reflectivity, i.e., permanent scatterers (PS), in the frame of time series of <span class="hlt">SAR</span> images acquired over the same area. For detecting land subsidence in Shanghai, China, this paper presents an attempt to explore an approach of PS-neighborhood networking <span class="hlt">SAR</span> interferometry. With use of 26 ERS-1/2 <span class="hlt">SAR</span> images acquired 1992 through 2002 over Shanghai, the analysis of subsiding process in time and space is performed on the basis of a strong network which is formed by connecting neighboring PSs according to a distance threshold. The linear and nonlinear subsidence, atmospheric effects as well as topographic errors can be separated effectively in this way. The subsidence velocity field in 10 years over Shanghai is also derived. It was found that the annual subsidence <span class="hlt">rates</span> in the study area range from -2.1 to -0.6 cm/yr, and the averaged subsidence <span class="hlt">rate</span> reaches -1.1 cm/yr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ESASP.724E..83Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ESASP.724E..83Z"><span id="translatedtitle">A Scheme of Intelligent Oil Spill Monitoring System by <span class="hlt">SAR</span> for Operational Application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeng, Kan; Ma, Youjun; Ding, Xingtao; Zhao, Chaofang; He, Mingxia</p> <p>2014-11-01</p> <p>A scheme of intelligent oil spill monitoring system by <span class="hlt">SAR</span> for operational application is presented. The system includes four key techniques. 1) Picking out dark targets from <span class="hlt">SAR</span> images using a new adaptive threshold segmentation algorithm based on evaluating the trends of background of <span class="hlt">SAR</span> image along the range direction. The algorithm is applicable for <span class="hlt">SAR</span> images of different satellites. 2) Filtering out some of look-alikes from dark targets by a chain of rules. 3) Extracting features from all the remained dark targets, selecting the most useful features and then discriminating the targets between oil spill and look-alikes by an artificial neural network (ANN). The feature extraction is based on lots of targets. The ANN experiences enough training. 4) Using an intelligent feedback with expert knowledge and relevant environment parameters to continually optimize system and improve the detection <span class="hlt">rate</span>. So far, the test on 1448 oil spill and look-alike targets from Envisat/ASAR images shows that the correct recognition <span class="hlt">rate</span> of the system can reach 88 % without the intelligent feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4833730','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4833730"><span id="translatedtitle"><span class="hlt">ABSORPTION</span> ANALYZER</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.</p> <p>1961-11-14</p> <p>A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron <span class="hlt">absorption</span> cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the <span class="hlt">absorption</span> cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. 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