Low Resolution Mode Research Articles

A New Approach for the Estimation of Lake Ice Thickness From Conventional Radar Altimetry

Lake ice thickness (LIT), a thematic product of Lakes as an Essential Climate Variable (ECV), is sensitive to changes in air temperature and on-ice snow mass. Here, a novel and efficient analytic method (retracking approach) is presented for the estimation of LIT from Ku-band (13.6 GHz) radar altimetry data. The new retracker, referred to as LRM_LIT, is based on the physical modeling of the conventional radar echoes (also called Low Resolution Mode or LRM) over ice-covered lakes that show a characteristic step-like feature in their leading edge attributed to the reflection of radar waves at the snow-ice and ice-water interfaces. The method is applied to Jason-2 and Jason-3 data acquired over Great Slave Lake, Canada, over three ice seasons (2013-2016). As expected, the agreement between the Jason-2 and Jason-3 LIT estimates over their overlapping period (2016 ice season) is excellent with a mean bias error of 0.013 m and root mean square error (RMSE) of 0.024 m. LIT estimates from LRM_LIT are in good agreement with simulations from a thermodynamic lake ice model and in situ measurements with RMSE values of the order of few centimeters for the three winter seasons. The retracker also provides a robust way to assess the accuracy of LIT estimates which is in the order of 0.10 m when the ice cover is well established and prior to melt onset. In addition, LRM_LIT captures the seasonal transitions during the freeze-up and breakup periods and ice growth over different winter seasons, making it a promising method for monitoring inter-annual variability and trends in LIT from past and current conventional radar altimetry missions.

Improving the diameters of interferometric calibrators with MATISSE

ABSTRACT A good knowledge of the angular diameters of stars used to calibrate the observables in stellar interferometry is fundamental. As the available precision for giant stars is worse than the required per cent level, we aim to improve the knowledge of many diameters using MATISSE (Multiple AperTure mid-Infrared SpectroScopic Experiment) data in its different instrumental configurations. Using the squared visibility MATISSE observable, we compute the angular diameter value, which ensures the best-fitting curves, assuming an intensity distribution of a uniform disc. We take into account that the transfer function varies over the wavelength and is different from one instrumental configuration to another. The uncertainties on the diameters are estimated using the residual bootstrap method. Using the low spectral resolution mode in the Lband, we observed a set of 35 potential calibrators selected in the Mid-infrared stellar Diameter and Flux Compilation Catalogue with diameters ranging from about 1 to 3 mas. We reach a precision on the diameter estimates in the range 0.6 per cent to 4.1 per cent. The study of the stability of the transfer function in visibility over two nights makes us confident in our results. In addition, we identify one star, 75 Vir initially present in the calibrator lists, for which our method does not converge, and prove to be a binary star. This leads us to the conclusion that our method is actually necessary to improve the quality of the astrophysical results obtained with MATISSE, and that it can be used as a useful tool for ‘bad calibrator’ detection.

Validation of the altimetry-based water levels from Sentinel-3A and B in the Inner Niger Delta

Abstract. The comprehension of water level fluctuations and the sustainability of the Inner Niger River Delta (IND) is a major concern for the scientific community, but also for the local population. Located in the centre of Mali, the heart of the Sahel, the delta is characterised by a floodable area of more than 32 000 km2 during the rainy season, which contributes very strongly to the vitality of local ecosystem, and is consequently classified as a Ramsar site under the international Convention for Wetlands. In addition, the Delta acts as an environmental and socio-economic development barometer for the entire sub-region. Nowadays, we can observe an increasing fragility of the delta due to climate change, desertification and human activities, and justifies the need for permanent monitoring. The present study is based on the recent successes of radar altimetry, originally designed to monitor the dynamics topography of the ocean, and now very frequently used to retrieve inland water levels, of lakes, rivers, and wetlands. Previous studies evaluated the performances of several radar altimetry missions including Low Resolution Mode (LRM) (Topex-Poseidon, Jason-1/2/3, ERS-2, ENVISAT, and SARAL, and Synthetic Aperture Radar (SAR) Sentinel-3A missions for water level retrievals over 1992–2017. More than 50 times series of water levels were build at the crossing between water bodies and Sentinel-3A and 3B over 2016–2020. Twenty-four comparisons between in-situ and altimetry-based time-series of water levels were achieved over the IND. RMSE generally lower than 0.7 m and r higher than 0.9 were obtained.

Precise inland surface altimetry (PISA) with nadir specular echoes from Sentinel-3: Algorithm and performance assessment

In the recent years satellite radar altimetry has evolved from pulse-limited low resolution mode (LRM) to a synthetic aperture radar (SAR) high resolution mode. The SAR mode focusses and coherently sums all radar return echoes within the 2-s time window the target surface area is in the antenna beam. In principle the SAR processing improves along-track resolution. Land contamination has been a major concern for inland waters altimetry and SAR can reduce land interference. This paper shows that the physics of specular echoes from smooth inland waters leads to a very different approach which we call precise inland surface altimetry (PISA). PISA uses only echoes within the specular “flash” period, which is approximately the time the satellite nadir crosses over the water body. The processing is four orders of magnitude less than SAR. Land interference is negligible because specular water echoes are usually >50 dB greater than land. Sentinel-3 SRAL dataset on the salar de Uyuni (Bolivia) is used to evaluate PISA ranging precision. During inundation (wet months), echoes are at the theoretical maximum radar cross section (RCS), σ = 129 dBsm, and ranging precision is ~1 mm. In dry months the echoes are quasi-specular, with σ = 70–100 dBsm, and ranging precision is ~1 cm. The precision assessment is made with variate-differences, with pass-to-pass repeatability, and by comparison with GPS measurements. In addition to the salar de Uyuni analysis we gathered σ statistics on five millions Sentinel-3 SRAL Ku-band altimeter bursts (one burst = 64 contiguous echoes) from 52 passes of Sentinel-3A track 167 over South America. We illustrate specular and quasi-specular waters on lakes, a river, and a fjord. Ranging precision is similar to Uyuni, in the 1 mm-1 cm range. Water surface slopes of 1–3 cm/km are detected. We propose a simple rule-set to distinguish specular waveforms (σ >100 dBsm, sidelobes (with Hamming window) of −37 dB or lower) and quasi-specular (σ >70 dBsm, sidelobes lower than −20 dB), and non-specular (sidelobes> − 20 dB). PISA is appropriate to specular and quasi-specular echoes.

Lipidomics of the Edible Brown Alga Wakame (Undaria pinnatifida) by Liquid Chromatography Coupled to Electrospray Ionization and Tandem Mass Spectrometry.

The lipidome of a brown seaweed commonly known as wakame (Undaria pinnatifida), which is grown and consumed around the world, including Western countries, as a healthy nutraceutical food or supplement, was here extensively examined. The study was focused on the characterization of phospholipids (PL) and glycolipids (GL) by liquid chromatography (LC), either hydrophilic interaction LC (HILIC) or reversed-phase LC (RPLC), coupled to electrospray ionization (ESI) and mass spectrometry (MS), operated both in high and in low-resolution mode. Through the acquisition of single (MS) and tandem (MS/MS) mass spectra more than 200 PL and GL of U. pinnatifida extracts were characterized in terms of lipid class, fatty acyl (FA) chain composition (length and number of unsaturations), and regiochemistry, namely 16 SQDG, 6 SQMG, 12 DGDG, 5 DGMG, 29 PG, 8 LPG, 19 PI, 14 PA, 19 PE, 8 PE, 38 PC, and 27 LPC. The FA (C16:0) was the most abundant saturated acyl chain, whereas the monounsaturated C18:1 and the polyunsaturated C18:2 and C20:4 chains were the prevailing ones. Odd-numbered acyl chains, iJ., C15:0, C17:0, C19:0, and C19:1, were also recognized. While SQDG exhibited the longest and most unsaturated acyl chains, C18:1, C18:2, and C18:3, in the sn-1 position of glycerol, they were preferentially located in the sn-2 position in the case of PL. The developed analytical approach might pave the way to extend lipidomic investigations also for other edible marine algae, thus emphasizing their potential role as a source of bioactive lipids.

Infrared photo-induced force microscopy unveils nanoscale features of Norway spruce fibre wall

Infrared photo-induced force microscopy (IR PiFM) was applied for imaging ultrathin sections of Norway spruce (Picea abies) at 800–1885 cm−1 with varying scanning steps from 0.6 to 30 nm. Cell wall sublayers were visualized in the low-resolution mode based on differences in their chemical composition. The spectra from the individual sublayers demonstrated differences in the orientation of cellulose elementary fibrils (EFs) and in the content and structure of lignin. The high-resolution images revealed 5–20 nm wide lignin-free areas in the S1 layer. Full spectra collected from a non-lignified spot and at a short distance apart from it verified an abrupt change in the lignin content and the presence of tangentially oriented EFs. Line scans across the lignin-free areas corresponded to a spatial resolution of ≤ 5 nm. The ability of IR PiFM to resolve structures based on their chemical composition differentiates it from transmission electron microscopy that can reach a similar spatial resolution in imaging ultrathin wood sections. In comparison with Raman imaging, IR PiFM can acquire chemical images with ≥ 50 times higher spatial resolution. IR PiFM is also a surface-sensitive technique that is important for reaching the high spatial resolution in anisotropic samples like the cell wall. All these features make IR PiFM a highly promising technique for analyzing the recalcitrant nature of lignocellulosic biomass for its conversion into various materials and chemicals.Graphic abstract

Evaluation of the Performances of Radar and Lidar Altimetry Missions for Water Level Retrievals in Mountainous Environment: The Case of the Swiss Lakes

Radar altimetry is now commonly used to provide long-term monitoring of inland water levels in complement to or for replacing disappearing in situ networks of gauge stations. Recent improvements in tracking and acquisition modes improved the quality the water retrievals. The newly implemented Open Loop mode is likely to increase the number of monitored water bodies owing to the use of an a priori elevation, especially in hilly and mountainous areas. The novelty of this study is to provide a comprehensive evaluation of the performances of the past and current radar altimetry missions according to their acquisition (Low Resolution Mode or Synthetic Aperture Radar) and tracking (close or open loop) modes, and acquisition frequency (Ku or Ka) in a mountainous area where tracking losses of the signal are likely to occur, as well as of the recently launched ICESat-2 and GEDI lidar missions. To do so, we evaluate the quality of water level retrievals from most radar altimetry missions launched after 1995 over eight lakes in Switzerland, using the recently developed ALtimetry Time Series software, to compare the performances of the new tracking and acquisition modes and also the impact of the frequency used. The combination of the Open Loop tracking mode with the Synthetic Aperture Radar acquisition mode on SENTINEL-3A and B missions outperforms the classical Low Resolution Mode of the other missions with a lake observability greater than 95%, an almost constant bias of (−0.17 ± 0.04) m, a RMSE generally lower than 0.07 m and a R most of the times higher than 0.85 when compared to in situ gauge records. To increase the number of lakes that can be monitored and the temporal sampling of the water level retrievals, data acquired by lidar altimetry missions were also considered. Very accurate results were also obtained with ICESat-2 data with RMSE lower than 0.06 and R higher than 0.95 when compared to in situ water levels. An almost constant bias (0.42 ± 0.03) m was also observed. More contrasted results were obtained using GEDI. As these data were available on a shorter time period, more analyses are necessary to determine their potential for retrieving water levels.

Elevation and Volume Changes in Greenland Ice Sheet From 2010 to 2019 Derived From Altimetry Data

Long-term altimetry data are one of the major sources to analyze the change in global ice reserves. This study focuses on the elevation and volume changes in the Greenland ice sheet (GrIS) from 2010 to 2019 derived from altimetry observations. In this study, the methods for determining surface elevation change rates are discussed, and specific strategies are designed. A new elevation difference method is proposed for CryoSat-2 synthetic aperture interferometric (SARin) mode observations. Through validation with Airborne Topographic Mapper (ATM) data, this new method is proved to be effective for slope terrains at the margins of the ice sheet. Meanwhile, a surface fit method is applied for the flat interior of the ice sheet where low resolution mode (LRM) observations are provided. The results of elevation change rates in the GrIS from 2010 to 2019 are eventually calculated by combining CryoSat-2 and ATM observations. An elevation change rate of −11.83 ± 1.14 cm·a−1 is revealed, corresponding to a volume change rate of −200.22 ± 18.26 km3·a−1. The results are compared with the elevation changes determined by Ice, Cloud, and Land Elevation Satellite (ICESat) from 2003 to 2009. Our results show that the overall volume change rate in the GrIS slowed down by approximately 10% during the past decade, and that the main contributor of GrIS ice loss has shifted from the southeast coast to the west margin of the ice sheet.

Synergic use of altimeter and model sea level data in inner and coastal seas

We analyse high rate (20 Hz) altimeter derived sea level information, both from Synthetic Aperture Radar (SAR) altimetry missions and Low Resolution Mode missions, in an inner sea and coastal environment. They are compared versus measured and high resolution model data. After a compact description of the relevant physical processes affecting the local sea level values, we focus on three specific passes on the Adriatic Sea, East of Italy. Our main finding is that altimeters and models provide both valuable, partially overlapping, but complementary, information to be exploited in parallel with a double purpose: to progressively approach the truth and to ensure the parallel improvement of both sources. From altimeter data there is a very strong suggestion that the spatial, and implicitly temporal, variability of the fields is much higher than shown by models. The reasons are discussed.

Real-Time Hand Gesture Recognition Based on Deep Learning YOLOv3 Model

Using gestures can help people with certain disabilities in communicating with other people. This paper proposes a lightweight model based on YOLO (You Only Look Once) v3 and DarkNet-53 convolutional neural networks for gesture recognition without additional preprocessing, image filtering, and enhancement of images. The proposed model achieved high accuracy even in a complex environment, and it successfully detected gestures even in low-resolution picture mode. The proposed model was evaluated on a labeled dataset of hand gestures in both Pascal VOC and YOLO format. We achieved better results by extracting features from the hand and recognized hand gestures of our proposed YOLOv3 based model with accuracy, precision, recall, and an F-1 score of 97.68, 94.88, 98.66, and 96.70%, respectively. Further, we compared our model with Single Shot Detector (SSD) and Visual Geometry Group (VGG16), which achieved an accuracy between 82 and 85%. The trained model can be used for real-time detection, both for static hand images and dynamic gestures recorded on a video.

Seeing Measurements with the Merak H$\upalpha$ Telescope

The parameter-search method (PSM) established by Rengaswamy, Ravindra, and Prabhu (Solar Phys. 294, 5, 2019) for measuring the terrestrial atmospheric seeing from long-exposure solar H $\upalpha$ images is further validated – through simulations – to include the effects of i) intermediate exposure-time, exposures that are neither as small as 1 to 20 ms used in solar speckle imaging in the visible nor as long as 1 second; ii) under-sampling of the data (with respect to the telescope’s diffraction-limit), and iii) non-ideal telescope point spread function. It is then applied to a large dataset to obtain the statistics of Fried’s parameter $r_{0}$ at Merak: a cold desert in the Himalayas. The bias due to intermediate exposure is well within the error budget. Under-sampling results in an underestimation of $r_{0}$ only when the seeing-limited point spread function is sampled at a rate worse than two pixels per seeing-limit, implying that $r_{0}$ estimated in the low-resolution mode is unreliable beyond $r_{0} = 10$ cm. The non-ideal telescope point spread function tends to reduce the estimated $r_{0}$ -values significantly only when the RMS wave-front error of the aberrated pupil is worse than $\lambda/14$ . The median seeing at Merak estimated from data spanning over five months is 2.7 arcseconds.

Estimate of the D/H Ratio in the Martian Upper Atmosphere from the Low Spectral Resolution Mode of MAVEN/IUVS

AbstractRecent Mars Atmosphere and Volatile EvolutioN (MAVEN) observations have shown unexpectedly large deuterium Lyman‐α emissions near the Martian southern summer solstice. The deuterium Lyman‐α brightness can reach ∼10% of the hydrogen Lyman‐α brightness below 200 km. In this study, we propose a method to estimate the D/H ratio in the Martian upper atmosphere through analysis of the Lyman‐α vertical profiles without the ability to spectrally separate the two atomic emission lines. Lyman‐α vertical profiles measured by MAVEN/IUVS at four periods are analyzed. During southern summer, the derived D/H ratios at 200 km are larger than the HDO/H2O ratio measured in the lower atmosphere, yet the extrapolated D/H ratio from 200 to 80 km agrees with the HDO/H2O ratio. This larger D/H ratio at higher altitude is attributed to the more efficient escape of hydrogen atoms compared to deuterium atoms. The method we describe accounts for uncertainties related to constraining the temperature and density profiles of H and D in the lower thermosphere. Because spectrally resolved D and H Lyman‐α measurements are not always available, this method provides a way to estimate D/H variations in their absence. This method will be useful for analysis of relevant data sets from past and future Mars missions.

A low power reconfigurable ADC for bioimpedance monitroing system

This article introduces a re-configurable pipeline analog-to-digital converter (ADC) deliberated for implantable surveillance devices for bio-impedance monitoring systems. To improve the efficiency of the bio-impedance method, an automatic adaptation circuit is introduced. This adaptive unit is responsible for setting the resolution and sampling rate on the basis of amplitude and frequency of the signal. Using a new, low-power automatic adaptation circuit low power consumption is achieved by using Dynamic Threshold metal oxide semiconductor (DTMOS) technique, it can automatically determine its setup. The converter has two modes of operations. In high-resolution mode, the converter has a 12-bit resolution and at low resolution mode, 8-bit resolution is used. The ADC bandwidth of low-speed mode is 100 kHz and high-speed mode is 1 GHz. The architecture is designed using 180 nm technology and simulated using Cadence virtuoso tool. The results achieved, low power consumption i.e. 0.844 mw, and it is operated with 1 V power supply. For signal to noise and distortion ratio (SNDR), effective number of bits (ENOB), the converter utilizes 71.06 dB, 11.45 in 12-bit and 72.3 dB, 7.41 in 8-bit mode respectively. By using proposed method around 20% of power consumption is reduced and 40% power supply is decreased. The proposed design is also used for mixed signal circuit testing.

The Copernicus Sentinel-6 mission: Enhanced continuity of satellite sea level measurements from space

Given the considerable range of applications within the European Union Copernicus system, sustained satellite altimetry missions are required to address operational, science and societal needs. This article describes the Copernicus Sentinel-6 mission that is designed to provide precision sea level, sea surface height, significant wave height, inland water heights and other products tailored to operational services in the ocean, climate, atmospheric and land Copernicus Services. Sentinel-6 provides enhanced continuity to the very stable time series of mean sea level measurements and ocean sea state started in 1992 by the TOPEX/Poseidon mission and follow-on Jason-1, Jason-2 and Jason-3 satellite missions. The mission is implemented through a unique international partnership with contributions from NASA, NOAA, ESA, EUMETSAT, and the European Union (EU). It includes two satellites that will fly sequentially (separated in time by 5 years). The first satellite, named Sentinel-6 Michael Freilich, launched from Vandenburg Air Force Base, USA on 21st November 2020. The satellite and payload elements are explained including required performance and their operation. The main payload is the Poseidon-4 dual frequency (C/Ku-band) nadir-pointing radar altimeter that uses an innovative interleaved mode. This enables radar data processing on two parallel chains the first provides synthetic aperture radar (SAR) processing in Ku-band to improve the received altimeter echoes through better along-track sampling and reduced measurement noise; the second provides a Low Resolution Mode that is fully backward-compatible with the historical reference altimetry measurements, allowing a complete inter-calibration between the state-of-the-art data and the historical record. A three-channel Advanced Microwave Radiometer for Climate (AMRC) provides measurements of atmospheric water vapour to mitigate degradation of the radar altimeter measurements. The main data products are explained and preliminary in-orbit Poseidon-4 altimeter data performance data are presented that demonstrate the altimeter to be performing within expectations.

Correction: Schlembach, F., et al. Round Robin Assessment of Radar Altimeter Low Resolution Mode and Delay-Doppler Retracking Algorithms for Significant Wave Height. Remote Sens. 2020, 12, 1254

Our earlier work on assessment of altimeter significant wave height (SWH) algorithms [...]

Estimate of the D/H ratio in the Martian upper atmosphere from the low spectral resolution mode of MAVEN/IUVS

Estimate of the D/H ratio in the Martian upper atmosphere from the low spectral resolution mode of MAVEN/IUVS

DRAGraces: A Pipeline for the GRACES High-resolution Spectrograph at Gemini*

Abstract This paper describes the software Data Reduction and Analysis for GRACES (DRAGraces), which is a pipeline reducing spectra from Gemini Remote Access to the CFHT ESPaDOnS Spectrograph (GRACES) at the Gemini North Telescope. The code is written in the IDL language. It is designed to find all the GRACES frames in a given directory, automatically determine the list of bias, flat, arc, and science frames, and perform the whole reduction and extraction within a few minutes. We compare the output from DRAGraces with that of the Open source Pipeline for ESPaDOnS Reduction and Analysis (OPERA), a pipeline developed at the Canada–France–Hawaii Telescope (CFHT) that also can extract GRACES spectra. Both pipelines were developed completely independently, yet they give very similar extracted spectra. They both have their advantages and disadvantages. For instance, DRAGraces is more straightforward and easy to use and is less likely to be derailed by a parameter that needs to be tweaked, while OPERA offers a more careful extraction that can be significantly superior when the highest resolution is required and when the signal-to-noise ratio is low. One should compare both before deciding which one to use for their science. Yet, both pipelines deliver a fairly comparable resolution power (R ∼ 52.8k and 36.6k for DRAGraces and R ∼ 58k and 40k for OPERA in high- and low-resolution spectral modes, respectively), wavelength solution, and signal-to-noise ratio per resolution element.

Characterizing slope correction methods applied to satellite radar altimetry data: A case study around Dome Argus in East Antarctica

Slope correction is important to improve the accuracy of satellite radar elevation measurements by mitigating the slope-induced error (SE), especially over uneven ground surfaces. Although several slope correction methods have been proposed, guidance in the form of stepwise algorithm on how to implement these methods in processing radar altimetric data at the coding level, and the differences among these methods need to be presented and discussed systematically. In this paper, three existing types of slope correction methods—the direct method (DM), intermediate method (IM), and relocation method (RM, further divided into RM1 and RM2)—are described in detail. In addition, their main differences and features for various scientific applications are analyzed. We conduct a systematic experiment with CryoSat-2 Low Resolution Mode (LRM) data in a physically stable area around Dome Argus in East Antarctica, where in-situ measurements were available for comparison. The slope correction is implemented separately using the three methods, with the latest high-accuracy Reference Elevation Model of Antarctica (REMA) as the a-priori topography model. The bias and precision of the slope-corrected CryoSat-2 data results from the RM2 is −0.18 ± 0.86 m based on the comparison with the field Global Navigation Satellite System (GNSS) data. The results from the RM2 indicate higher precision compared to those from the RM1. According to the correlation analysis of the slope-corrected CryoSat-2 data results (RM1 and RM2), the bias enlarges and the precision becomes worse when the surface slope increases from 0 to 0.85°. After a comprehensively comparative analysis, we find that the results from the RM1 and RM2 are superior in precision (0.93 m and 0.86 m) with respect to the GNSS data. The relatively low precision (1.22 m) from the IM is due to the potential error from the a-priori digital elevation model (DEM). The DM has the lowest precision (2.66 m). Another experiment over rough topography in West Antarctica is carried out for comparison, especially between the RM1 (precision of 15.27 m) and RM2 (precision of 16.25 m). In general, the RM is recommended for the SE elimination among the three methods. Moreover, the RM2 is firstly considered over smooth topography due to the superior performance in bias and precision, while the RM1 is more suggested over the rough topography because of the slightly smaller bias and better precision. The IM relies much on the accuracy of the a-prior DEM and is not usually recommended, because of the strict requirement in the sampling time between the radar altimetry data and the a-priori DEM to avoid any surface change over time.

Bone Structure Analysis of the Radius Using Ultrahigh Field (7T) MRI: Relevance of Technical Parameters and Comparison with 3T MRI and Radiography.

Bone fractal signature analysis (FSA—also termed bone texture analysis) is a tool that assesses structural changes that may relate to clinical outcomes and functions. Our aim was to compare bone texture analysis of the distal radius in patients and volunteers using radiography and 3T and 7T magnetic resonance imaging (MRI)—a patient group (n = 25) and a volunteer group (n = 25) were included. Participants in the patient group had a history of chronic wrist pain with suspected or confirmed osteoarthritis and/or ligament instability. All participants had 3T and 7T MRI including T1-weighted turbo spin echo (TSE) sequences. The 7T MRI examination included an additional high-resolution (HR) T1 TSE sequence. Radiographs of the wrist were acquired for the patient group. When comparing patients and volunteers (unadjusted for gender and age), we found a statistically significant difference of horizontal and vertical fractal dimensions (FDs) using 7T T1 TSE-HR images in low-resolution mode (horizontal: p = 0.04, vertical: p = 0.01). When comparing radiography to the different MRI sequences, we found a statistically significant difference for low- and high-resolution horizontal FDs between radiography and 3T T1 TSE and 7T T1 TSE-HR. Vertical FDs were significantly different only between radiographs and 3T T1 TSE in the high-resolution mode; FSA measures obtained from 3T and 7T MRI are highly dependent on the sequence and reconstruction resolution used, and thus are not easily comparable between MRI systems and applied sequences.

High-precision analysis of potassium isotopes by MC-ICP-MS without collision cell using cool plasma technique in low-resolution mode

A practical method to measure K isotopes with MC-ICP-MS without a collision cell in low-resolution mode.