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This document is a correction notice for an article published in the Journal of Neurology. It acknowledges an error in the original article where Table 1 was duplicated as Table 2. The correction provides the correct version of Table 2, which presents the results of a study comparing the use of 3T and 7T MRI in various neurological conditions. The study found that 7T MRI generally provided better visibility and delineation of structures compared to 3T MRI, but there were variations in the results depending on the specific condition being studied. [Extracted from the article]

Bacterial chromosomes are folded into tightly regulated three-dimensional structures to ensure proper transcription, replication, and segregation of the genetic information. Direct visualization of chromosomal shape within bacterial cells is hampered by cell-wall confinement and the optical diffraction limit. Here, we combine cell-shape manipulation strategies, high-resolution fluorescence microscopy techniques, and genetic engineering to visualize the shape of unconfined bacterial chromosome in real-time in live Bacillus subtilis cells that are expanded in volume. We show that the chromosomes predominantly exhibit crescent shapes with a non-uniform DNA density that is increased near the origin of replication (oriC). Additionally, we localized ParB and BsSMC proteins – the key drivers of chromosomal organization – along the contour of the crescent chromosome, showing the highest density near oriC. Opening of the BsSMC ring complex disrupted the crescent chromosome shape and instead yielded a torus shape. These findings help to understand the threedimensional organization of the chromosome and the main protein complexes that underlie its structure. The spatial structure of the bacterial chromosome is resolved in the absence of confinement by the cell boundary. Size-expanded cells reveal a crescent-shaped Bacillussubtilis chromosome and the effects of ParB and SMC proteins on chromosome shape. [ABSTRACT FROM AUTHOR]

Objective: Recently, the 7 Tesla (7 T) Epilepsy Task Force published recommendations for 7 T magnetic resonance imaging (MRI) in patients with pharmaco-resistant focal epilepsy in pre-surgical evaluation. The objective of this study was to implement and evaluate this consensus protocol with respect to both its practicability and its diagnostic value/potential lesion delineation surplus effect over 3 T MRI in the pre-surgical work-up of patients with pharmaco-resistant focal onset epilepsy. Methods: The 7 T MRI protocol consisted of T1-weighted, T2-weighted, high-resolution-coronal T2-weighted, fluid-suppressed, fluid-and-white-matter-suppressed, and susceptibility-weighted imaging, with an overall duration of 50 min. Two neuroradiologists independently evaluated the ability of lesion identification, the detection confidence for these identified lesions, and the lesion border delineation at 7 T compared to 3 T MRI. Results: Of 41 recruited patients > 12 years of age, 38 were successfully measured and analyzed. Mean detection confidence scores were non-significantly higher at 7 T (1.95 ± 0.84 out of 3 versus 1.64 ± 1.19 out of 3 at 3 T, p = 0.050). In 50% of epilepsy patients measured at 7 T, additional findings compared to 3 T MRI were observed. Furthermore, we found improved border delineation at 7 T in 88% of patients with 3 T-visible lesions. In 19% of 3 T MR-negative cases a new potential epileptogenic lesion was detected at 7 T. Conclusions: The diagnostic yield was beneficial, but with 19% new 7 T over 3 T findings, not major. Our evaluation revealed epilepsy outcomes worse than ILAE Class 1 in two out of the four operated cases with new 7 T findings. [ABSTRACT FROM AUTHOR]

Bacterial cells require DNA segregation machinery to properly distribute a genome to both daughter cells upon division. The most common system involved in chromosome and plasmid segregation in bacteria is the ParABS system. A core protein of this system - partition protein B (ParB) - regulates chromosome organization and chromosome segregation during the bacterial cell cycle. Over the past decades, research has greatly advanced our knowledge of the ParABS system. However, many intricate details of the mechanism of ParB proteins were only recently uncovered using in vitro single-molecule techniques. These approaches allowed the exploration of ParB proteins in precisely controlled environments, free from the complexities of the cellular milieu. This review covers the early developments of this field but emphasizes recent advances in our knowledge of the mechanistic understanding of ParB proteins as revealed by in vitro single-molecule methods. Furthermore, we provide an outlook on future endeavors in investigating ParB, ParB-like proteins, and their interaction partners. [ABSTRACT FROM AUTHOR]

VirB is a transcriptional activator of virulence in the gram-negative bacterium Shigella flexneri encoded by the large invasion plasmid, pINV. It counteracts the transcriptional silencing by the nucleoid structuring protein, H-NS. Mutations in virB lead to loss of virulence. Studies suggested that VirB binds to specific DNA sequences, remodels the H-NS nucleoprotein complexes, and changes DNA supercoiling. VirB belongs to the superfamily of ParB proteins which are involved in plasmid and chromosome partitioning often as part of a ParABS system. Like ParB, VirB forms discrete foci in Shigella flexneri cells harbouring pINV. Our results reveal that purified preparations of VirB specifically bind the ribonucleotide CTP and slowly but detectably hydrolyse it with mild stimulation by the virS targeting sequences found on pINV. We show that formation of VirB foci in cells requires a virS site and CTP binding residues in VirB. Curiously, DNA stimulation of clamp closure appears efficient even without a virS sequence in vitro. Specificity for entrapment of virS DNA is however evident at elevated salt concentrations. These findings suggest that VirB acts as a CTP-dependent DNA clamp and indicate that the cellular microenvironment contributes to the accumulation of VirB specifically at virS sites. This study sheds light on the mechanism of transcription activation by which VirB, a virulence transcription activator in Shigella flexneri, the causative agent of the diarrheal disease shigellosis, uses the ribonucleotide CTP as a cofactor to load at specific DNA sites. [ABSTRACT FROM AUTHOR]

SMC and SMC-like complexes promote chromosome folding and genome maintenance in all domains of life. Recently, they were also recognized as factors in cellular immunity against foreign DNA. In bacteria and archaea, Wadjet and Lamassu are anti-plasmid/ phage defence systems, while Smc5/6 and Rad50 complexes play a role in anti-viral immunity in humans. This raises an intriguing paradox — how can the same, or closely related, complexes on one hand secure the integrity and maintenance of chromosomal DNA, while on the other recognize and restrict extrachromosomal DNA? In this minireview, we will briefly describe the latest understanding of each of these complexes in immunity including speculations on how principles of SMC(-like) function may explain how the systems recognize linear or circular forms of invading DNA. [ABSTRACT FROM AUTHOR]

Purpose: Developmental dyslexia in alphabetic languages (DD) is characterized by a phonological deficit. Since logographic scripts rely predominantly on visual and morphological processing, reading performance in DD can be assumed to be less impaired when reading logographic scripts. Methods: 40 German-speaking children (18 with DD, 22 not reading-impaired—group C; 9–11 years) received Chinese lessons. Eye movements (EM) were recorded during naming single alphabetic words, pictures (confrontational) and Chinese characters to be named in German and Chinese. The main outcome variables were: Articulation latency, numbers and durations of fixations. Quality of life (QoL) was assessed by questionnaires. Results: While reading alphabetic words, articulation latencies and numbers of fixations were significantly higher for group DD than for group C (AL-DD = 1.13, AL-C = 0.84, p<.001; FN-DD = 3.50; FN-C = 2.00, p<.001). For naming pictures and Chinese characters in German and in Chinese, no significant group differences were found for any of the EM variables. The percentage of correct answers was high for German naming (DD = 86.67%, C = 95.24%; p =.015) and lower for Chinese naming in both groups, but significantly lower in group DD, especially for Chinese naming (DD = 56.67%, C: 83.77%; p =.003). QoL differed between groups from the children's perspective only at posttest. Parents of group DD perceived their children's QoL to be lower compared with parents of group C at pre- and posttest. Conclusions: Children with dyslexia performed as well as group C during naming Chinese characters in German and in Chinese regarding their EM variables, presumably because they processed Chinese characters by the visuo-spatial pathway with direct access to the semantic system. However, the significantly lower percentage of correct answers especially during Chinese naming showed that group DD had more difficulties naming Chinese characters than group C, which could be attributed to their phonological deficit, among other factors. Trial registration: German clinical trials register (DRKS00015697). [ABSTRACT FROM AUTHOR]

Estimates of the past thermal state of the land surface are crucial to assess the magnitude of current anthropogenic climate change as well as to assess the ability of Earth System Models (ESMs) to forecast the evolution of the climate near the ground, which is not included in standard meteorological records. Subsurface temperature reacts to long-term changes in surface energy balance – from decadal to millennial time scales – thus constituting an important record of the dynamics of the climate system that contributes, with low-frequency information, to proxy-based paleoclimatic reconstructions. Broadly used techniques to retrieve past temperature and heat flux histories from subsurface temperature profiles based on a singular value decomposition (SVD) algorithm were able to provide robust global estimates for the last millennium, but the approaches used to derive the corresponding 95 % confidence interval were wrong from a statistical point of view in addition to being difficult to interpret. To alleviate the lack of a meaningful framework for estimating uncertainties in past temperature and heat flux histories at regional and global scales, we combine a new bootstrapping sampling strategy with the broadly used SVD algorithm and assess its performance against the original SVD technique and another technique based on generating perturbed parameter ensembles of inversions. The new bootstrap approach is able to reproduce the prescribed surface temperature series used to derive an artificial profile. Bootstrap results are also in agreement with the global mean surface temperature history and the global mean heat flux history retrieved in previous studies. Furthermore, the new bootstrap technique provides a meaningful uncertainty range for the inversion of large sets of subsurface temperature profiles. We suggest the use of this new approach particularly for aggregating results from a number of individual profiles, and to this end, we release the programs used to derive all inversions in this study as a suite of codes labeled CIBOR v1: Codes for Inverting BORholes, version 1. [ABSTRACT FROM AUTHOR]

Monitoring of the periglacial environment is relevant for many disciplines including glaciology, natural hazard management, geomorphology, and geodesy. Since October 2022, Rock Glacier Velocity (RGV) is a new Essential Climate Variable (ECV) product within the Global Climate Observing System (GCOS). However, geodetic surveys at high elevation remain very challenging due to environmental and logistical reasons. During the past decades, the introduction of low-cost global navigation satellite system (GNSS) technologies has allowed us to increase the accuracy and frequency of the observations. Today, permanent GNSS instruments enable continuous surface displacement observations at millimetre accuracy with a sub-daily resolution. In this paper, we describe decennial time series of GNSS observables as well as accompanying meteorological data. The observations comprise 54 positions located on different periglacial landforms (rock glaciers, landslides, and steep rock walls) at altitudes ranging from 2304 to 4003 ma.s.l. and spread across the Swiss Alps. The primary data products consist of raw GNSS observables in RINEX format, inclinometers, and weather station data. Additionally, cleaned and aggregated time series of the primary data products are provided, including daily GNSS positions derived through two independent processing tool chains. The observations documented here extend beyond the dataset presented in the paper and are currently continued with the intention of long-term monitoring. An annual update of the dataset, available at 10.1594/PANGAEA.948334 ,​​​​​​​ is planned. With its future continuation, the dataset holds potential for advancing fundamental process understanding and for the development of applied methods in support of e.g. natural hazard management. [ABSTRACT FROM AUTHOR]

SMC complexes, loaded at ParB-parS sites, are key mediators of chromosome organization in bacteria. ParA/Soj proteins interact with ParB/Spo0J in a pathway involving adenosine triphosphate (ATP)-dependent dimerization and DNA binding, facilitating chromosome segregation in bacteria. In Bacillus subtilis, ParA/Soj also regulates DNA replication initiation and along with ParB/Spo0J is involved in cell cycle changes during endospore formation. The first morphological stage in sporulation is the formation of an elongated chromosome structure called an axial filament. Here, we show that a major redistribution of SMC complexes drives axial filament formation in a process regulated by ParA/Soj. Furthermore, and unexpectedly, this regulation is dependent on monomeric forms of ParA/Soj that cannot bind DNA or hydrolyze ATP. These results reveal additional roles for ParA/Soj proteins in the regulation of SMC dynamics in bacteria and yet further complexity in the web of interactions involving chromosome replication, segregation and organization, controlled by ParAB and SMC. [ABSTRACT FROM AUTHOR]

Estimates of the past thermal state of the land surface are crucial to assess the magnitude of current anthropogenic climate change, as well as to assess the ability of Earth System Models to forecast the evolution of the climate near the ground, not included in standard meteorological records. Subsurface temperature data are able to retrieve long-term changes in surface energy balance -from decadal to millennial time scales, thus constituting an important record of the dynamics of the climate system that contributes low-frequency information to proxy-based paleoclimatic reconstructions. A broadly used technique to retrieve past temperature and heat flux histories from subsurface temperature profiles based on a Singular Value Decomposition (SVD) algorithm was able to take into account a limited number of sources of uncertainty, with recent works attempting to increase the number of factors considered in uncertainty estimates. Nevertheless, the SVD methodology did not define a statistical framework for aggregating inversions of individual profiles to derive global results, which lead to estimates of global and regional uncertainties that are difficult to interpret. To alleviate the lack of a conceptual framework for estimating uncertainties in past temperature and heat flux histories at regional and global scales, we combine a new bootstrapping sampling strategy with the broadly used SVD algorithm, and assess its performance against the original SVD technique and another technique based on generating perturbed parameter ensembles of inversions. The new bootstrap approach is able to reproduce the prescribed surface temperature series used to derive an artificial profile. Bootstrap results are also in agreement with the global mean surface temperature history and the global mean heat flux history retrieved in previous studies. Furthermore, the new bootstrap technique provides with a meaningful uncertainty range for the inversion of large sets of subsurface temperature profiles. We suggest the use of this new approach particularly for aggregating results from a number of individual profiles, and to this end, we release the programs used to derive all inversions in this study as a suite of codes labelled CIBOR 1.0: Codes for Inverting BORholes, version 1.0. [ABSTRACT FROM AUTHOR]

Soil freeze–thaw processes play a fundamental role in the hydrology, geomorphology, ecology, thermodynamics, and soil chemistry of cold regions' landscapes. In understanding these processes, the temperature of the soil is used as a proxy to represent the partitioning of soil ice and water content via a soil freezing characteristic curve (SFCC). This mathematical construct relates the soil ice content to a specific temperature for a particular soil. SFCCs depend on many factors, including soil properties (e.g., porosity and composition), soil pore water pressure, dissolved salts, (hysteresis in) freezing/thawing point depression, and the degree of saturation, all of which can be site-specific and time-varying characteristics. SFCCs have been measured using various methods for diverse soils since 1921, but, to date, these data have not been broadly compared. This is in part because they had not previously been compiled in a single dataset. The dataset presented in this publication includes SFCC data digitized or received from authors, and it includes both historic and modern studies. The data are stored in an open-source repository, and an R package is available to facilitate their use. Aggregating the data has pointed out some data gaps, namely that there are few studies on coarse soils and comparably few in situ measurements of SFCCs in mountainous environments. It is hoped that this dataset (10.5281/zenodo.5592825;) will aid in the development of SFCC theory and improve SFCC approximations in soil freeze–thaw modelling activities. [ABSTRACT FROM AUTHOR]

Simple Summary: Magnetic resonance spectroscopic imaging is an imaging method that can map the distribution of multiple biochemicals in the human brain in one scan. Using stronger magnetic fields, such as 7 Tesla, allows for higher resolution images and more biochemical maps. To test these results, we compared it to positron emission tomography, the established clinical standard for metabolic imaging. This comparison mainly looked at the overlap between regions with increased signal between both methods. We found that the molecules glutamine and glycine, only mappable at 7 Tesla, corresponded better to positron emission tomography than the commonly used choline. (1) Background: Recent developments in 7T magnetic resonance spectroscopic imaging (MRSI) made the acquisition of high-resolution metabolic images in clinically feasible measurement times possible. The amino acids glutamine (Gln) and glycine (Gly) were identified as potential neuro-oncological markers of importance. For the first time, we compared 7T MRSI to amino acid PET in a cohort of glioma patients. (2) Methods: In 24 patients, we co-registered 7T MRSI and routine PET and compared hotspot volumes of interest (VOI). We evaluated dice similarity coefficients (DSC), volume, center of intensity distance (CoI), median and threshold values for VOIs of PET and ratios of total choline (tCho), Gln, Gly, myo-inositol (Ins) to total N-acetylaspartate (tNAA) or total creatine (tCr). (3) Results: We found that Gln and Gly ratios generally resulted in a higher correspondence to PET than tCho. Using cutoffs of 1.6-times median values of a control region, DSCs to PET were 0.53 ± 0.36 for tCho/tNAA, 0.66 ± 0.40 for Gln/tNAA, 0.57 ± 0.36 for Gly/tNAA, and 0.38 ± 0.31 for Ins/tNAA. (4) Conclusions: Our 7T MRSI data corresponded better to PET than previous studies at lower fields. Our results for Gln and Gly highlight the importance of future research (e.g., using Gln PET tracers) into the role of both amino acids. [ABSTRACT FROM AUTHOR]

Soil freeze-thaw processes play a fundamental role in the hydrology, geomorphology, ecology, thermodynamics and soil chemistry of a cold-regions landscape. In understanding these processes, the temperature of the soil is used as a proxy to represent the soil ice content through a soil freezing characteristic curve (SFCC). This mathematical construct relates the soil ice content to a specific temperature for a particular soil. SFCCs depend on many factors including soil properties (e.g., porosity, composition, etc.), soil pore water pressure, dissolved salts, (hysteresis in) freezing/thawing point depression, and degree of saturation, all of which can be site-specific and time varying. SFCCs have been measured using various methods for diverse soils since 1921, and to date this data has not been broadly compared, in part because it has not previously been compiled in a single data set. The dataset presented in this publication includes SFCC data digitized or received from authors, and includes both historic and modern studies. The data is stored in an open-source repository, and an R package is available to facilitate its use. Aggregating the data has pointed out some data gaps, namely that there are few studies of coarse soils, and comparably few in-situ measurements of SFCCs in mountainous environments. It is hoped that this dataset will aid in the development of SFCC theory, and improve SFCC approximations in soil freeze-thaw modelling activities. [ABSTRACT FROM AUTHOR]

This correction notice is for an article titled "Direct observation of a crescent-shape chromosome in expanded Bacillus subtilis cells" published in Nature Communications. The correction addresses an error in the "Acknowledgement" section, where the grant number for funding the work in S.G. lab was incorrect. The correct grant number is 310030_197770. The correction has been made in both the PDF and HTML versions of the article. The authors of the article are Miloš Tišma, Florian Patrick Bock, Jacob Kerssemakers, Hammam Antar, Aleksandre Japaridze, Stephan Gruber, and Cees Dekker. [Extracted from the article]

Purpose Recently, a 3D‐concentric ring trajectory (CRT)‐based free induction decay (FID)‐MRSI sequence was introduced for fast high‐resolution metabolic imaging at 7 T. This technique provides metabolic ratio maps of almost the entire brain within clinically feasible scan times, but its robustness has not yet been thoroughly investigated. Therefore, we have assessed quantitative concentration estimates and their variability in healthy volunteers using this approach. Methods: We acquired whole‐brain 3D‐CRT‐FID‐MRSI at 7 T in 15 min with 3.4 mm nominal isometric resolution in 24 volunteers (12 male, 12 female, mean age 27 ± 6 years). Concentration estimate maps were calculated for 15 metabolites using internal water referencing and evaluated in 55 different regions of interest (ROIs) in the brain. Data quality, mean metabolite concentrations, and their inter‐subject coefficients of variation (CVs) were compared for all ROIs. Results: Of 24 datasets, one was excluded due to motion artifacts. The concentrations of total choline, total creatine, glutamate, myo‐inositol, and N‐acetylaspartate in 44 regions were estimated within quality thresholds. Inter‐subject CVs (mean over 44 ROIs/minimum/maximum) were 9%/5%/19% for total choline, 10%/6%/20% for total creatine, 11%/7%/24% for glutamate, 10%/6%/19% for myo‐inositol, and 9%/6%/19% for N‐acetylaspartate. Discussion: We defined the performance of 3D‐CRT‐based FID‐MRSI for metabolite concentration estimate mapping, showing which metabolites could be robustly quantified in which ROIs with which inter‐subject CVs expected. However, the basal brain regions and lesser‐signal metabolites in particular remain as a challenge due susceptibility effects from the proximity to nasal and auditory cavities. Further improvement in quantification and the mitigation of B0/B1‐field inhomogeneities will be necessary to achieve reliable whole‐brain coverage. [ABSTRACT FROM AUTHOR]

Purpose: State‐of‐the‐art whole‐brain MRSI with spatial‐spectral encoding and multichannel acquisition generates huge amounts of data, which must be efficiently processed to stay within reasonable reconstruction times. Although coil combination significantly reduces the amount of data, currently it is performed in image space at the end of the reconstruction. This prolongs reconstruction times and increases RAM requirements. We propose an alternative k‐space‐based coil combination that uses geometric deep learning to combine MRSI data already in native non‐Cartesian k‐space. Methods: Twelve volunteers were scanned at a 3T MR scanner with a 20‐channel head coil at 10 different positions with water‐unsuppressed MRSI. At the eleventh position, water‐suppressed MRSI data were acquired. Data of 7 volunteers were used to estimate sensitivity maps and form a base for simulating training data. A neural network was designed and trained to remove the effect of sensitivity profiles of the coil elements from the MRSI data. The water‐suppressed MRSI data of the remaining volunteers were used to evaluate the performance of the new k‐space‐based coil combination relative to that of a conventional image‐based alternative. Results: For both approaches, the resulting metabolic ratio maps were similar. The SNR of the k‐space‐based approach was comparable to the conventional approach in low SNR regions, but underperformed for high SNR. The Cramér‐Rao lower bounds show the same trend. The analysis of the FWHM showed no difference between the two methods. Conclusion: k‐Space‐based coil combination of MRSI data is feasible and reduces the amount of raw data immediately after their sampling. [ABSTRACT FROM AUTHOR]

Eukaryotic cells employ three SMC (structural maintenance of chromosomes) complexes to control DNA folding and topology. The Smc5/6 complex plays roles in DNA repair and in preventing the accumulation of deleterious DNA junctions. To elucidate how specific features of Smc5/6 govern these functions, we reconstituted the yeast holo‐complex. We found that the Nse5/6 sub‐complex strongly inhibited the Smc5/6 ATPase by preventing productive ATP binding. This inhibition was relieved by plasmid DNA binding but not by short linear DNA, while opposing effects were observed without Nse5/6. We uncovered two binding sites for Nse5/6 on Smc5/6, based on an Nse5/6 crystal structure and cross‐linking mass spectrometry data. One binding site is located at the Smc5/6 arms and one at the heads, the latter likely exerting inhibitory effects on ATP hydrolysis. Cysteine cross‐linking demonstrated that the interaction with Nse5/6 anchored the ATPase domains in a non‐productive state, which was destabilized by ATP and DNA. Under similar conditions, the Nse4/3/1 module detached from the ATPase. Altogether, we show how DNA substrate selection is modulated by direct inhibition of the Smc5/6 ATPase by Nse5/6. SYNOPSIS: The Smc5/6 complex prevents accumulation of toxic DNA junctions during DNA replication and repair, in order to enable faithful chromosome segregation in mitosis and meiosis. Biochemical reconstitution of the yeast holo‐complex reveals a central role of the Nse5/6 sub‐complex in DNA substrate selection. Nse5/6 promotes ATP‐dependent, salt‐stable DNA association of Smc5/6.Nse5/6 inhibits the Smc5/6 ATPase by preventing productive ATP binding in the absence of DNA.Nse5/6 contacts the Smc5/6 hexamer via multiple interfaces including one at the SMC joint and one at the heads.Lysine cross‐linking (XL‐MS) and cysteine cross‐linking uncover major conformational changes upon Nse5/6 association.A crystal structure of the Nse5/6 core shows a HEAT‐repeat‐like organization. [ABSTRACT FROM AUTHOR]

Permafrost warming is coinciding with accelerated mass movements, talking place especially in steep, mountainous topography. While this observation is backed up by evidence and analysis of both remote sensing as well as repeat terrestrial surveys undertaken since decades much knowledge is to be gained about the specific details, the variability and the processes governing these mass movements in the mountain cryosphere. This dataset collates data of continuously acquired kinematic observations obtained through in-situ Global Navigation Satellite Systems (GNSS) instruments that have been designed and implemented in a large-scale multi field-site monitoring campaign across the whole Swiss Alps. The landforms covered include rock glaciers, high-alpine steep bedrock bedrock as well as landslide sites, most of which are situated in permafrost areas. The dataset was acquired at 54 different stations situated at locations from 2304 to 4003 m a.s.l and comprises 209’948 daily positions derived through double-differential GNSS post-processing. Apart from these, the dataset contains down-sampled and cleaned time series of weather station and inclinometer data as well as the full set of GNSS observables in RINEX format. Furthermore the dataset is accompanied by tools for processing and data management in order to facilitate reuse, open alternate usage opportunities and support the life-long living data process with updates. To date this dataset has seen numerous use cases in research as well as natural-hazard mitigation and adaptation due to climate change. [ABSTRACT FROM AUTHOR]

The accurate simulation of heat transfer with phase change is a central problem in cryosphere studies. This is because the non-linear behaviour of enthalpy as function of temperature can prevent thermal models of snow, ice, and frozen soil from converging to the correct solution. Existing numerical techniques rely on increased temporal resolution in trying to keep corresponding errors within acceptable bounds. Here, we propose an algorithm, originally applied to solve water flow in soils, as a method to solve these integration issues with guaranteed convergence and conservation of energy for any time step size. We review common modelling approaches, focusing on the fixed-grid method and on frozen soil. Based on this, we develop a conservative formulation of the governing equation and outline problems of alternative formulations in discretized form. Then, we apply the nested Newton–Casulli–Zanolli (NCZ) algorithm to a one-dimensional finite-volume discretization of the energy–enthalpy formulation. Model performance is demonstrated against the Neumann and Lunardini analytical solutions and by comparing results from numerical experiments with integration time steps of 1 h, 1 d, and 10 d. Using our formulation and the NCZ algorithm, the convergence of the solver is guaranteed for any time step size. With this approach, the integration time step can be chosen to match the timescale of the processes investigated. [ABSTRACT FROM AUTHOR]

The fronts of two rock glaciers located in South Tyrol (Italian Alps) failed on 13 August 2014, initiating debris flows in their downslope channels. A multimethod approach including climate, meteorological, and ground temperature data analysis, aerial image correlation, as well as geotechnical testing and modeling, led to the reconstruction of the two events. An integrated investigation of static predisposing factors, slowly changing preparatory factors, and potential triggering events shed light on the most likely reasons for such failures. Our results suggest that the occurrence of front destabilization at the two rock glaciers can only partly be explained by the occurrence of heavy rainfall events. Indeed, antecedent hydrological and thermal ground conditions were characterized by a saturated active layer favored by a snow‐rich winter and extensive precipitation in late spring and summer. Also, the rising trend of air temperature during spring and summer months since 1950s might explain the concurrent marked displacement of the two rock glaciers. Indeed, geotechnical investigations have provided strong indications that one of the investigated rock glacier fronts was at a marginally stable state prior to 2014. As rainfall events more intense than the one that occurred in August 2014 were previously recorded in the same area without resulting failures at the studied rock glaciers, we propose that both predisposing and preparatory destabilizing factors have played a key role in the 2014 rock glacier front failures. [ABSTRACT FROM AUTHOR]

Recent studies have shown the cold and arid trans-Himalayan region comprises significant areas underlain by permafrost. While the information on the permafrost characteristics of this region started emerging, the governing energy regime is of particular interest. This paper presents the results of a surface energy balance (SEB) study carried out in the upper Ganglass catchment in the Ladakh region of India which feeds directly into the Indus River. The point-scale SEB is estimated using the 1D mode of the GEOtop model for the period of 1 September 2015 to 31 August 2017 at 4727 m a.s.l. elevation. The model is evaluated using field-monitored snow depth variations (accumulation and melting), outgoing long-wave radiation and near-surface ground temperatures and showed good agreement with the respective simulated values. For the study period, the SEB characteristics of the study site show that the net radiation (29.7 Wm-2) was the major component, followed by sensible heat flux (-15.6 Wm-2), latent heat flux (-11.2 Wm-2) and ground heat flux (-0.5 Wm-2). During both years, the latent heat flux was highest in summer and lowest in winter, whereas the sensible heat flux was highest in post-winter and gradually decreased towards the pre-winter season. During the study period, snow cover builds up starting around the last week of December, facilitating ground cooling during almost 3 months (October to December), with sub-zero temperatures down to -20 ∘ C providing a favourable environment for permafrost. It is observed that the Ladakh region has a very low relative humidity in the range of 43 % compared to e.g. ∼70 % in the European Alps, resulting in lower incoming long-wave radiation and strongly negative net long-wave radiation averaging ∼-90 Wm-2 compared to -40 Wm-2 in the European Alps. Hence, land surfaces at high elevation in cold and arid regions could be overall colder than the locations with higher relative humidity, such as the European Alps. Further, it is found that high incoming short-wave radiation during summer months in the region may be facilitating enhanced cooling of wet valley bottom surfaces as a result of stronger evaporation. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to compare reading speeds (RS) of either paragraphs of text or single sentences in patients with maculopathy by investigating the repeatability of RS to decide which text type to use in studies on patients with maculopathy. Methods: RS was measured for standardized texts in 25 participants with a central scotoma due to maculopathy (mean age 77.8 years ± 9.9 SD, mean binocular visual acuity 0.65 logMAR (±0.85 SD), median magnification requirement 3-fold). Reading 3 single sentences taken from the Radner reading charts (sample #1, #2, and #3) of 14 words and reading 3 paragraphs of International Reading Speed Texts (IReST, sample # 3, #6, and #10) with a mean of 132 (±3.2 SD) words, each in German, were compared. The 6 texts were read aloud in random order from a closed-circuit TV system, with size adjusted according to the individual magnification requirement. Reading time was measured by stopwatch, and speed was calculated in correctly read words per minute (wpm). Differences in RS depending on text length (single sentence vs. paragraph) and text sample were calculated by the Bland-Altman analysis. Results: The mean RS showed no significant difference between 2 charts of the same kind (sentences: 93 wpm ± 37 SD; paragraphs: 95 wpm ± 38 SD). RS differences between 2 charts were lower in paragraphs than in single sentences. Highest correlations of RS between all 6 texts existed between the 3 IReST text samples (r = 0.98, 0.98, and 0.98) compared with the 3 Radner sentences (r = 0.89, 0.81, and 0.90). The inter-chart reliability (coefficient of repeatability) was smaller for the paragraphs (12.9 wpm) than for the single sentences (36.4 wpm). Conclusion: In patients with maculopathy, single sentences are well suited for single measurement of RS. For repeated measurements (e.g., monitoring the course of a reading disorder or assessing effects of interventions), paragraphs are preferable because of their lower variability of RS between the paragraphs. [ABSTRACT FROM AUTHOR]

Purpose: To explore the impact of temporal motion‐induced coil sensitivity changes on CEST‐MRI at 7T and its correction using interleaved volumetric EPI navigators, which are applied for real‐time motion correction. Methods: Five healthy volunteers were scanned via CEST. A 4‐fold correction pipeline allowed the mitigation of (1) motion, (2) motion‐induced coil sensitivity variations, ΔB1‐, (3) motion‐induced static magnetic field inhomogeneities, ΔB0, and (4) spatially varying transmit RF field fluctuations, ΔB1+. Four CEST measurements were performed per session. For the first 2, motion correction was turned OFF and then ON in absence of voluntary motion, whereas in the other 2 controlled head rotations were performed. During post‐processing ΔB1‐ was removed additionally for the motion‐corrected cases, resulting in a total of 6 scenarios to be compared. In all cases, retrospective ∆B0 and ‐ΔB1+ corrections were performed to compute artifact‐free magnetization transfer ratio maps with asymmetric analysis (MTRasym). Results: Dynamic ΔB1‐ correction successfully mitigated signal deviations caused by head motion. In 2 frontal lobe regions of volunteer 4, induced relative signal errors of 10.9% and 3.9% were reduced to 1.1% and 1.0% after correction. In the right frontal lobe, the motion‐corrected MTRasym contrast deviated 0.92%, 1.21%, and 2.97% relative to the static case for Δω = 1, 2, 3 ± 0.25 ppm. The additional application of ΔB1‐ correction reduced these deviations to 0.10%, 0.14%, and 0.42%. The fully corrected MTRasym values were highly consistent between measurements with and without intended head rotations. Conclusion: Temporal ΔB1‐ cause significant CEST quantification bias. The presented correction pipeline including the proposed retrospective ΔB1‐ correction significantly reduced motion‐related artifacts on CEST‐MRI. [ABSTRACT FROM AUTHOR]

The Rad50‐Mre11 nuclease complex plays a vital role in DNA repair in all domains of life. It recognizes and processes DNA double‐strand breaks. Rad50 proteins fold into an extended structure with a 20 to 60 nm long coiled coil connecting a globular ABC ATPase domain with a zinc hook dimerization domain. A published structure of an archaeal Rad50 zinc hook shows coiled coils pointing away from each other. Here we present the crystal structure of an alternate conformation displaying co‐aligned coiled coils. Archaeal Rad50 may thus switch between rod‐shaped and ring‐like conformations as recently proposed for a bacterial homolog. [ABSTRACT FROM AUTHOR]

The central Slave Geological Province is situated 450–650 km from the presumed spreading centre of the Keewatin Dome of the Laurentide Ice Sheet, and it differs from the western Canadian Arctic, where recent thaw-induced landscape changes in Laurentide ice-marginal environments are already abundant. Although much of the terrain in the central Slave Geological Province is mapped as predominantly bedrock and ice-poor, glacial deposits of varying thickness occupy significant portions of the landscape in some areas, creating a mosaic of permafrost conditions. Limited evidence of ice-rich ground, a key determinant of thaw-induced landscape change, exists. Carbon and soluble cation contents in permafrost are largely unknown in the area. Twenty-four boreholes with depths up to 10 m were drilled in tundra north of Lac de Gras to address these regional gaps in knowledge and to better inform projections and generalizations at a coarser scale. Excess-ice contents of 20 %–60 %, likely remnant Laurentide basal ice, are found in upland till, suggesting that thaw subsidence of metres to more than 10 m is possible if permafrost were to thaw completely. Beneath organic terrain and in fluvially reworked sediment, aggradational ice is found. The variability in abundance of ground ice poses long-term challenges for engineering, and it makes the area susceptible to thaw-induced landscape change and mobilization of sediment, solutes and carbon several metres deep. The nature and spatial patterns of landscape changes, however, are expected to differ from ice-marginal landscapes of western Arctic Canada, for example, based on greater spatial and stratigraphic heterogeneity. Mean organic-carbon densities in the top 3 m of soil profiles near Lac de Gras are about half of those reported in circumpolar statistics; deeper deposits have densities ranging from 1.3–10.1 kg C m -3 , representing a significant additional carbon pool. The concentration of total soluble cations in mineral soils is lower than at previously studied locations in the western Canadian Arctic. This study can inform permafrost investigations in other parts of the Slave Geological Province, and its data can support scenario simulations of future trajectories of permafrost thaw. Preserved Laurentide basal ice can support new ways of studying processes and phenomena at the base of an ice sheet. [ABSTRACT FROM AUTHOR]

Correct bioriented attachment of sister chromatids to the mitotic spindle is essential for chromosome segregation. In budding yeast, the conserved protein shugoshin (Sgo1) contributes to biorientation by recruiting the protein phosphatase PP2A-Rts1 and the condensin complex to centromeres. Using peptide prints, we identified a Serine-Rich Motif (SRM) of Sgo1 that mediates the interaction with condensin and is essential for centromeric condensin recruitment and the establishment of biorientation. We show that the interaction is regulated via phosphorylation within the SRM and we determined the phospho-sites using mass spectrometry. Analysis of the phosphomimic and phosphoresistant mutants revealed that SRM phosphorylation disrupts the shugoshin–condensin interaction. We present evidence that Mps1, a central kinase in the spindle assembly checkpoint, directly phosphorylates Sgo1 within the SRM to regulate the interaction with condensin and thereby condensin localization to centromeres. Our findings identify novel mechanisms that control shugoshin activity at the centromere in budding yeast. Author summary: Proper chromosome segregation in eukaryotes is ensured through correct attachment of the spindle microtubules to the centromeric chromosomal regions. The attachment is mediated via the multimolecular proteinaceous complex called the kinetochore. This enables the establishment of bioirentation, when each sister chromatid is attached to microtubules emanating from opposite spindle poles. Shugoshin (Sgo1) is a conserved centromeric protein that facilitates biorientation through its interactions with the protein phosphatase PP2A/Rts1, chromosome passenger complex and centromeric condensin. Here, we identified a serine-rich motif that is required for the interaction of shugoshin with the condensin complex. We show that loss of this region impairs condensin enrichment at the centromere, chromosome biorientation, segregation as well as the function of the chromosome passenger complex in the error correction. Moreover, the interaction is phosphoregulated, as phosphorylation of the serine-rich motif on Sgo1 disrupts its interaction with condensin. Finally, we show that the conserved spindle assembly checkpoint kinase Mps1 is responsible for this phosphorylation. Our findings uncover novel regulatory mechanisms that facilitate proper chromosome segregation. [ABSTRACT FROM AUTHOR]

ERA5-Land (ERA5L) is a reanalysis product derived by running the land component of ERA5 at increased resolution. This study evaluates ERA5L soil temperature in permafrost regions based on observations and published permafrost products. We find that ERA5L overestimates soil temperature in northern Canada and Alaska but underestimates it in mid–low latitudes, leading to an average bias of -0.08 ∘ C. The warm bias of ERA5L soil is stronger in winter than in other seasons. As calculated from its soil temperature, ERA5L overestimates active-layer thickness and underestimates near-surface (<1.89 m) permafrost area. This is thought to be due in part to the shallow soil column and coarse vertical discretization of the land surface model and to warmer simulated soil. The soil temperature bias in permafrost regions correlates well with the bias in air temperature and with maximum snow height. A review of the ERA5L snow parameterization and a simulation example both point to a low bias in ERA5L snow density as a possible cause for the warm bias in soil temperature. The apparent disagreement of station-based and areal evaluation techniques highlights challenges in our ability to test permafrost simulation models. While global reanalyses are important drivers for permafrost simulation, we conclude that ERA5L soil data are not well suited for informing permafrost research and decision making directly. To address this, future soil temperature products in reanalyses will require permafrost-specific alterations to their land surface models. [ABSTRACT FROM AUTHOR]

Heave and subsidence of the ground surface can offer insight into processes of heat and mass transfer in freezing and thawing soils. Additionally, subsidence is an important metric for monitoring and understanding the transformation of permafrost landscapes under climate change. Corresponding ground observations, however, are sparse and episodic. A simple tilt-arm apparatus with logging inclinometer has been developed to measure heave and subsidence of the ground surface with hourly resolution and millimeter accuracy. This contribution reports data from the first two winters and the first full summer, measured at three sites with contrasting organic and frost-susceptible soils in warm permafrost. The patterns of surface movement differ significantly between sites and from a prediction based on the Stefan equation and observed ground temperature. The data are rich in features of heave and subsidence that are several days to several weeks long and that may help elucidate processes in the ground. For example, late-winter heave followed by thawing and subsidence, as reported in earlier literature and hypothesized to be caused by infiltration and refreezing of water into permeable frozen ground, has been detected. An early-winter peak in heave, followed by brief subsidence, is discernible in a previous publication but so far has not been interpreted. An effect of precipitation on changes in surface elevation can be inferred with confidence. These results highlight the potential of ground-based observation of subsidence and heave as an enabler of progress in process understanding, modeling and interpretation of remotely sensed data. [ABSTRACT FROM AUTHOR]

Purpose: A properly characterized macromolecular (MM) contribution is essential for accurate metabolite quantification in FID‐MRSI. MM information can be included into the fitting model as a single component or parameterized and included over several individual MM resonances, which adds flexibility when pathologic changes are present but is prone to potential overfitting. This study investigates the effects of different MM models on MRSI reproducibility. Methods: Clinically feasible, high‐resolution FID‐MRSI data were collected in ~5 min at 7 Tesla from 10 healthy volunteers and quantified via LCModel (version 6.3) with 3 basis sets, each with a different approach for how the MM signal was handled: averaged measured whole spectrum (full MM), 9 parameterized components (param MM) with soft constraints to avoid overparameterization, or without any MM information included in the fitting prior knowledge. The test–retest reproducibility of MRSI scans was assessed voxel‐wise using metabolite coefficients of variation and intraclass correlation coefficients and compared between the basis sets. Correlations of concentration estimates were investigated for the param MM fitting model. Results: The full MM model provided the most reproducible quantification of total NAA, total Cho, myo‐inositol, and glutamate + glutamine ratios to total Cr (coefficients of variations ≤ 8%, intraclass correlation coefficients ≥ 0.76). Using the param MM model resulted in slightly lower reproducibility (up to +3% higher coefficients of variations, up to −0.1 decreased intraclass correlation coefficients). The quantification of the parameterized macromolecules did not affect quantification of the overlapping metabolites. Conclusion: Clinically feasible FID‐MRSI with an experimentally acquired MM spectrum included in prior knowledge provides highly reproducible quantification for the most common neurometabolites in healthy volunteers. Parameterization of the MM spectrum may be preferred as a compromise between quantification accuracy and reproducibility when the MM content is expected to be pathologically altered. [ABSTRACT FROM AUTHOR]

Simulations of land-surface processes and phenomena often require driving time series of meteorological variables. Corresponding observations, however, are unavailable in most locations, even more so, when considering the duration, continuity and data quality required. Atmospheric reanalyses provide global coverage of relevant meteorological variables, but their use is largely restricted to grid-based studies. This is because technical challenges limit the ease with which reanalysis data can be applied to models at the site scale. We present the software toolkit GlobSim, which automates the downloading, interpolation and scaling of different reanalyses – currently ERA5, ERA-Interim, JRA-55 and MERRA-2 – to produce meteorological time series for user-defined point locations. The resulting data have consistent structure and units to efficiently support ensemble simulation. The utility of GlobSim is demonstrated using an application in permafrost research. We perform ensemble simulations of ground-surface temperature for 10 terrain types in a remote tundra area in northern Canada and compare the results with observations. Simulation results reproduced seasonal cycles and variation between terrain types well, demonstrating that GlobSim can support efficient land-surface simulations. Ensemble means often yielded better accuracy than individual simulations and ensemble ranges additionally provide indications of uncertainty arising from uncertain input. By improving the usability of reanalyses for research requiring time series of climate variables for point locations, GlobSim can enable a wide range of simulation studies and model evaluations that previously were impeded by technical hurdles in obtaining suitable data. [ABSTRACT FROM AUTHOR]

The Canadian Land Surface Scheme and Canadian Terrestrial Ecosystem Model (CLASS-CTEM) together form the land surface component of the Canadian Earth System Model (CanESM). Here, we investigate the impact of changes to CLASS-CTEM that are designed to improve the simulation of permafrost physics. Overall, 18 tests were performed, including changing the model configuration (number and depth of ground layers, different soil permeable depth datasets, adding a surface moss layer), and investigating alternative parameterizations of soil hydrology, soil thermal conductivity, and snow properties. To evaluate these changes, CLASS-CTEM outputs were compared to 1570 active layer thickness (ALT) measurements from 97 observation sites that are part of the Global Terrestrial Network for Permafrost (GTN-P), 105 106 monthly ground temperature observations from 132 GTN-P borehole sites, a blend of five observation-based snow water equivalent (SWE) datasets (Blended-5), remotely sensed albedo, and seasonal discharge for major rivers draining permafrost regions. From the tests performed, the final revised model configuration has more ground layers (increased from 3 to 20) extending to greater depth (from 4.1 to 61.4 m) and uses a new soil permeable depths dataset with a surface layer of moss added. The most beneficial change to the model parameterizations was incorporation of unfrozen water in frozen soils. These changes to CLASS-CTEM cause a small improvement in simulated SWE with little change in surface albedo but greatly improve the model performance at the GTN-P ALT and borehole sites. Compared to the GTN-P observations, the revised CLASS-CTEM ALTs have a weighted mean absolute error (wMAE) of 0.41–0.47 m (depending on configuration), improved from >2.5 m for the original model, while the borehole sites see a consistent improvement in wMAE for most seasons and depths considered, with seasonal wMAE values for the shallow surface layers of the revised model simulation of at most 3.7 ∘ C, which is 1.2 ∘ C more than the wMAE of the screen-level air temperature used to drive the model as compared to site-level observations (2.5 ∘ C). Subgrid heterogeneity estimates were derived from the standard deviation of ALT on the 1 km 2 measurement grids at the GTN-P ALT sites, the spread in wMAE in grid cells with multiple GTN-P ALT sites, as well as from 35 boreholes measured within a 1200 km 2 region as part of the Slave Province Surficial Materials and Permafrost Study. Given the size of the model grid cells (approximately 2.8 ∘), subgrid heterogeneity makes it likely difficult to appreciably reduce the wMAE of ALT or borehole temperatures much further. [ABSTRACT FROM AUTHOR]

Purpose: To assess the performance, in the presence of scanner instabilities, of three dynamic correction methods which integrate ∆B0 mapping into the chemical exchange saturation transfer (CEST) measurement and three established static ∆B0‐correction approaches. Methods: A homogeneous phantom and five healthy volunteers were scanned with a CEST sequence at 7 T. The in vivo measurements were performed twice: first with unaltered system frequency and again applying frequency shifts during the CEST acquisition. In all cases, retrospective voxel‐wise ∆B0‐correction was performed using one intrinsic and two extrinsic [prescans with dual‐echo gradient‐echo and water saturation shift referencing (WASSR)] static approaches. These were compared with two intrinsic [using phase data directly generated by single‐echo or double‐echo GRE (gradient‐echo) CEST readout (CEST‐GRE‐2TE)] and one extrinsic [phase from interleaved dual‐echo EPI (echo planar imaging) navigator (NAV‐EPI‐2TE)] dynamic ∆B0‐correction approaches [allowing correction of each Z‐spectral point before magnetization transfer ratio asymmetry (MTRasym) analysis]. Results: All three dynamic methods successfully mapped the induced drift. The intrinsic approaches were affected by the CEST labeling near water (∆ω < |0.3| ppm). The MTRasym contrast was distorted by the frequency drift in the brain by up to 0.21%/Hz when static ∆B0‐corrections were applied, whereas the dynamic ∆B0 corrections reduced this to <0.01%/Hz without the need of external scans. The CEST‐GRE‐2TE and NAV‐EPI‐2TE resulted in highly consistent MTRasym values with/without drift for all subjects. Conclusion: Reliable correction of scanner instabilities is essential to establish clinical CEST MRI. The three dynamic approaches presented improved the ∆B0‐correction performance significantly in the presence of frequency drift compared to established static methods. Among them, the self‐corrected CEST‐GRE‐2TE was the most accurate and straightforward to implement. [ABSTRACT FROM AUTHOR]

Purpose: Inhomogeneities in the static magnetic field (B0) deteriorate MRSI data quality by lowering the spectral resolution and SNR. MRSI with low spatial resolution is also prone to lipid bleeding. These problems are increasingly problematic at ultra‐high fields. An approach to tackling these challenges independent of B0‐shim hardware is to increase the spatial resolution. Therefore, we investigated the effect of improved spatial resolution on spectral quality and quantification at 4 field strengths. Methods: Whole‐brain MRSI data was simulated for 3 spatial resolutions and 4 B0s based on experimentally acquired MRI data and simulated free induction decay signals of metabolites and lipids. To compare the spectral quality and quantification, we derived SNR normalized to the voxel size (nSNR), linewidth and metabolite concentration ratios, their Cramer‐Rao‐lower‐bounds (CRLBs), and the absolute percentage error (APE) of estimated concentrations compared to the gold standard for the whole‐brain and 8 brain regions. Results: At 7T, we found up to a 3.4‐fold improved nSNR (in the frontal lobe) and a 2.8‐fold reduced linewidth (in the temporal lobe) for 1 cm3 versus 0.25 cm3 resolution. This effect was much more pronounced at higher and less homogenous B0 (1.6‐fold improved nSNR and 1.8‐fold improved linewidth in the parietal lobe at 3T). This had direct implications for quantification: the volume of reliably quantified spectra increased with resolution by 1.2‐fold and 1.5‐fold (when thresholded by CRLBs or APE, respectively). Conclusion: MRSI data quality benefits from increased spatial resolution particularly at higher B0, and leads to more reliable metabolite quantification. In conjunction with the development of better B0 shimming hardware, this will enable robust whole‐brain MRSI at ultra‐high field. [ABSTRACT FROM AUTHOR]

Proton MRS (1H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good‐quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi‐adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use. [ABSTRACT FROM AUTHOR]

Simulations of land-surface processes and phenomena often require driving time series of meteorological variables. Corresponding observations, however, are unavailable in most locations, even more so, when considering the duration, continuity and data quality required. Atmospheric reanalyses provide global coverage of relevant meteorological variables, but their use is largely restricted to grid-based studies. This is because technical challenges limit the ease with which reanalysis data can be applied to models at the site scale. We present the software toolkit GlobSim, which automates the downloading, interpolation and scaling of different reanalyses - currently ERA-5, ERA-Interim, JRA-55 and MERRA-2 - to produce meteorological time series for user-defined point locations. The resulting data have consistent structure and units to efficiently support ensemble simulation. The utility of GlobSim is demonstrated using an application in permafrost research. We perform ensemble simulations of ground-surface temperature for ten terrain types in a remote tundra area in northern Canada and compare the results with observations. Simulation results reproduced seasonal cycles and variation between terrain types well, demonstrating that GlobSim can support efficient land-surface simulations. Ensemble means often yielded better accuracy than individual simulation and ensemble ranges additionally provide indications of uncertainty arising from uncertain input. By improving the usability of reanalyses for research requiring time-series of climate variables for point locations, GlobSim can enable a wide range of simulation studies and model evaluations that previously were impeded by technical hurdles in obtaining suitable data. [ABSTRACT FROM AUTHOR]

The PermaSense project is an ongoing interdisciplinary effort between geo-science and engineering disciplines and started in 2006 with the goals of realizing observations that previously have not been possible. Specifically, the aims are to obtain measurements in unprecedented quantity and quality based on technological advances. This paper describes a unique >10-year data record obtained from in situ measurements in steep bedrock permafrost in an Alpine environment on the Matterhorn Hörnligrat, Zermatt, Switzerland, at 3500 ma.s.l. Through the utilization of state-of-the-art wireless sensor technology it was possible to obtain more data of higher quality, make these data available in near real time and tightly monitor and control the running experiments. This data set (10.1594/PANGAEA.897640,) constitutes the longest, densest and most diverse data record in the history of mountain permafrost research worldwide with 17 different sensor types used at 29 distinct sensor locations consisting of over 114.5 million data points captured over a period of 10 or more years. By documenting and sharing these data in this form we contribute to making our past research reproducible and facilitate future research based on these data, e.g., in the areas of analysis methodology, comparative studies, assessment of change in the environment, natural hazard warning and the development of process models. Finally, the cross-validation of four different data types clearly indicates the dominance of thawing-related kinematics. [ABSTRACT FROM AUTHOR]

The Canadian Land Surface Scheme and Canadian Terrestrial Ecosystem Model (CLASS-CTEM) together form the land surface component of the Canadian Earth System model (CanESM). Here we investigate the impact of changes to CLASS-CTEM that are designed to improve the simulation of permafrost physics. Eighteen tests were performed including changing the model configuration (number and depth of ground layers, different soil permeable depth datasets, adding a surface moss layer), and investigating alternative parameterizations of soil hydrology, soil thermal conductivity and snow properties. To evaluate these changes, outputs from CLASS-CTEM were compared to 1570 active layer thickness (ALT) measurements from 97 observation sites that are part of the Global Terrestrial Network for Permafrost (GTN-P), 105 106 monthly ground temperature observations from 132 GTN-P borehole sites, a blend of 5 observation-based snow water equivalent (SWE) datasets (Blended-5), remotely-sensed albedo, and seasonal discharge for major rivers draining permafrost regions. From the tests performed, the final revised model configuration has more ground layers (increased from 3 to 20) extending to greater depth (from 4.1m to 61.4m) and uses a new soil permeable depths dataset with a surface layer of moss added. The most beneficial change to the model parameterizations was incorporation of unfrozen water in frozen soils. These changes to CLASS-CTEM cause a small improvement in simulated SWE with little change in surface albedo but greatly improve the model performance at the GTN-P ALT and borehole sites. Compared to the GTN-P observations, the revised CLASS-CTEM ALTs have a weighted mean absolute error (wMAE) of 0.41-0.47m (depending on configuration), improved from >2.5m for the original model, while the borehole sites see a consistent improvement in wMAE for most seasons and depths considered, with seasonal wMAE values for the shallow surface layers of the revised model simulation at most 1.2°C greater than those calculated for the model driving screen-level air temperature compared to observations at the sites. Sub-grid heterogeneity estimates were derived from the standard deviation of ALT on the 1km² measurement grids at the GTN-P ALT sites, the spread in wMAE in grid cells with multiple GTN-P ALT sites, as well as from 35 boreholes measured within a 1200km² region as part of the Slave Province Surficial Materials and Permafrost Study. Given the size of the model grid cells (ca. 2.8°), sub-grid heterogeneity makes it likely difficult to appreciably reduce the wMAE of ALT or borehole temperatures much further. [ABSTRACT FROM AUTHOR]

The PermaSense project is an ongoing interdisciplinary effort between geo-science and engineering disciplines started in 2006 with the goals to make observations possible that previously have not been possible. Specifically the aims are to obtain measurements data in unprecedented quantity and quality based on technological advances. This paper describes a unique ten+ year data record obtained from in-situ measurements in steep bedrock permafrost in an Alpine environment on the Matterhorn Hörnligrat, Zermatt Switzerland at 3500 m a.s.l. Through the utilization of state-of-the-art wireless sensor technology it was possible to obtain more data of higher quality, make this data available in near real-time and tightly monitor and control the running experiments. This data set (DOI: https://doi.org/10.1594/PANGAEA.897640, Weber et al., 2019a) constitutes the longest, densest and most diverse data record in the history of mountain permafrost research worldwide with 17 different sensor types used at 29 distinct sensor locations consisting of over 114.5 million data points captured over a period of ten+ years. By documenting and sharing this data in this form we contribute to making our past research reproducible and facilitate future research based on this data e.g. in the area of analysis methodology, comparative studies, assessment of change in the environment, natural hazard warning and the development of process models. [ABSTRACT FROM AUTHOR]

Rockfalls and rock avalanches are a recurrent process in high mountain areas like the Mont Blanc massif. These processes are surveyed due to the hazard they present for infrastructure and alpinists. While rockfalls and rock avalanches have been documented for the last 150 years, we know very little about their frequency since the Last Glacial Maximum (LGM). In order to improve our understanding, it is imperative to date them on a longer timescale. A pilot campaign using Terrestrial Cosmogenic Nuclide (TCN) dating of five samples was carried out in 2006 at the Aiguille du Midi (3842 m a.s.l.). In 2011, a larger scale study (20 samples) was carried out in five other test sites in the Mont Blanc massif. This paper presents the exposure ages of the 2011 TCN study as well as the updated exposure ages of the 2006 study using newer TCN dating parameters. Most of these exposure ages lie within the Holocene but three ages are Pleistocene (59.87 ± 6.10 ka for the oldest). A comparison of these ages with air temperature and glacier cover proxies explored the possible relationship between the most active rockfall periods and the warmest periods of the Holocene: two clusters of exposure ages have been detected, corresponding to the Middle Holocene (8.2-4.2 ka) and the Roman Warm Period (c. 2 ka) climate periods. Some recent rockfalls have also been dated (< 0.56 ka). [ABSTRACT FROM AUTHOR]

Purpose: Full‐slice magnetic resonance spectroscopic imaging at ≥ 7 T is especially vulnerable to lipid contaminations arising from regions close to the skull. This contamination can be mitigated by improving the point spread function via higher spatial resolution sampling and k‐space filtering, but this prolongs scan times and reduces the signal‐to‐noise ratio (SNR) efficiency. Currently applied parallel imaging methods accelerate magnetic resonance spectroscopic imaging scans at 7T, but increase lipid artifacts and lower SNR‐efficiency further. In this study, we propose an SNR‐efficient spatial‐spectral sampling scheme using concentric circle echo planar trajectories (CONCEPT), which was adapted to intrinsically acquire a Hamming‐weighted k‐space, thus termed density‐weighted‐CONCEPT. This minimizes voxel bleeding, while preserving an optimal SNR. Theory and Methods: Trajectories were theoretically derived and verified in phantoms as well as in the human brain via measurements of five volunteers (single‐slice, field‐of‐view 220 × 220 mm2, matrix 64 × 64, scan time 6 min) with free induction decay magnetic resonance spectroscopic imaging. Density‐weighted‐CONCEPT was compared to (a) the originally proposed CONCEPT with equidistant circles (here termed e‐CONCEPT), (b) elliptical phase‐encoding, and (c) 5‐fold Controlled Aliasing In Parallel Imaging Results IN Higher Acceleration accelerated elliptical phase‐encoding. Results: By intrinsically sampling a Hamming‐weighted k‐space, density‐weighted‐CONCEPT removed Gibbs‐ringing artifacts and had in vivo +9.5%, +24.4%, and +39.7% higher SNR than e‐CONCEPT, elliptical phase‐encoding, and the Controlled Aliasing In Parallel Imaging Results IN Higher Acceleration accelerated elliptical phase‐encoding (all P < 0.05), respectively, which lead to improved metabolic maps. Conclusion: Density‐weighted‐CONCEPT provides clinically attractive full‐slice high‐resolution magnetic resonance spectroscopic imaging with optimal SNR at 7T. Magn Reson Med 79:2874–2885, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. [ABSTRACT FROM AUTHOR]