bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive precision in block‐Jacobi preconditioning for iterative sparse linear system solvers
Authors: Anzt Hartwig , Dongarra Jack , Flegar Goran , Higham Nicholas J. , Quintana‐Ortí Enrique S. 
Published: March 2018

SummaryWe propose an adaptive scheme to reduce communication overhead caused by data movement by selectively storing the diagonal blocks of a block‐Jacobi preconditioner in different precision formats (half, single, or double). This specialized preconditioner can then be combined with any Krylov subspace method for the solution of sparse linear systems to perform all arithmetic in double precision. We assess the effects of the adaptive precision preconditioner on the iteration count and data transfer cost of a preconditioned conjugate gradient solver. A preconditioned conjugate gradient method is, in general, a memory bandwidth‐bound algorithm, and therefore its execution time and energy consumption are largely dominated by the costs of accessing the problem's data in memory. Given this observation, we propose a model that quantifies the time and energy savings of our approach based on the assumption that these two costs depend linearly on the bit length of a floating point number. Furthermore, we use a number of test problems from the SuiteSparse matrix collection to estimate the potential benefits of the adaptive block‐Jacobi preconditioning scheme.
Accelerating explicit ODE methods on GPUs by kernel fusion
Authors: Korch Matthias , Werner Tim 
Published: March 2018

SummaryGraphics processing units (GPUs) have a promising architecture for implementing highly parallel solution methods for systems of ordinary differential equations (ODEs). However, their high performance comes at the price of caveats such as small caches or wide SIMD. For ODE methods, optimizing the memory access pattern is often crucial. In this article, instead of considering only one specific method, we generalize the description of explicit ODE methods by using data flow graphs consisting of basic operations that are suitable to cover the types of computations occurring in all common explicit methods. After showing that the straightforward approach for processing the data flow graph by calling one kernel per basic operation is memory bound, we explain how the number of memory accesses can be reduced by the kernel fusion technique, which fuses several basic operations into one kernel. Moreover, we will present enabling transformations that allow additional fusions and thus can reduce the number of memory accesses even further. We apply these optimizations to three different classes of explicit ODE methods: embedded Runge–Kutta (RK) methods, parallel iterated RK (PIRK) methods, and peer methods. A detailed experimental evaluation on three modern GPUs showed speedups between 1.86 and 3.51 compared to unfused implementations.
Growth of Bulk GaN from Gas Phase
Authors: Siche Dietmar , Zwierz Radoslaw 
Published: March 2018

AbstractThe present status of the GaN bulk growth by vapor growth methods is reviewed and is shortly classified into all methods with bulk growth potential. The hydride vapor phase epitaxy (HVPE) as the most developed and already commercialized method using chlorine as transport agent was frequently reviewed before. However, it does not yield true bulk GaN, suffers from perfection limiting heteroepitaxy, direction depending growth rate, parasitic growth and by‐product formation, the latter both limiting the process duration. Therefore, in this review other methods are considered. Alternative transport agents are pronounced, like iodine, hydrogen, oxygen, water and the pseudo halide CN− ‐ ion, which are not able to reveal potential for bulk growth. These mostly less successful approaches, are sometimes repeated, because not adequately published.
Identifying the Mechanism of Continued Growth of the Solid–Electrolyte Interphase
Authors: Single Fabian , Latz Arnulf , Horstmann Birger 
Published: March 2018

AbstractContinued growth of the solid–electrolyte interphase (SEI) is the major reason for capacity fade in modern lithium‐ion batteries. This growth is made possible by a yet unidentified transport mechanism that limits the passivating ability of the SEI towards electrolyte reduction. We, for the first time, differentiate the proposed mechanisms by analyzing their dependence on the electrode potential. Our calculations are compared to recent experimental capacity‐fade data. We show that the potential dependence of SEI growth facilitated by solvent diffusion, electron conduction, or electron tunneling qualitatively disagrees with the experimental observations. Only diffusion of Li interstitials results in a potential dependence matching the experiments. Therefore, we identify the diffusion of neutral radicals, such as Li interstitials, as the cause of long‐term SEI growth.
Manual dexterity in young and healthy older adults. 1. Age‐ and gender‐related differences in unimanual and bimanual performance
Authors: Vasylenko Olena , Gorecka Marta M. , Rodríguez‐Aranda Claudia 
Published: March 2018

AbstractThis study aimed to better characterize age‐related differences in dexterity by using an integrative approach where movement times and kinematics were measured for both hands. Forty‐five young (age 19–31) and 55 healthy older adults (age 60–88) were evaluated during unimanual and bimanual performance of the Purdue Pegboard Test. Gender effects were also assessed. From video‐recorded data, movement times and kinematics were obtained for reaching, grasping, transport, and inserting. Results showed that older adults had longer movement times for grasping and inserting with the right hand, and across all movements with the left hand. Kinematic differences were found in path length, linear, and angular velocity. The patterns of slowing were similar in unimanual and bimanual tasks. Gender effects showed more slowing in older males than older females. Age differences in dexterity not only comprise slowing of movements but also kinematic alterations. The importance of gender in hand function was demonstrated.
The nature of the beast: examining climate adaptation options in forests with stand‐replacing fire regimes
Authors: Halofsky Joshua S. , Donato Daniel C. , Franklin Jerry F. , Halofsky Jessica E. , Peterson David L. , Harvey Brian J. 
Published: March 2018

AbstractBuilding resilience to natural disturbances is a key to managing forests for adaptation to climate change. To date, most climate adaptation guidance has focused on recommendations for frequent‐fire forests, leaving few published guidelines for forests that naturally experience infrequent, stand‐replacing wildfires. Because most such forests are inherently resilient to stand‐replacing disturbances, and burn severity mosaics are largely indifferent to manipulations of stand structure (i.e., weather‐driven, rather than fuel‐driven fire regimes), we posit that pre‐fire climate adaptation options are generally fewer in these regimes relative to others. Outside of areas of high human value, stand‐scale fuel treatments commonly emphasized for other forest types would undermine many of the functions, ecosystem services, and other values for which these forests are known. For stand‐replacing disturbance regimes, we propose that (1) managed wildfire use (e.g., allowing natural fires to burn under moderate conditions) can be a useful strategy as in other forest types, but likely confers fewer benefits to long‐term forest resilience and climate adaptation, while carrying greater socio‐ecological risks; (2) reasoned fire exclusion (i.e., the suppression component of a managed wildfire program) can be an appropriate strategy to maintain certain ecosystem conditions and services in the face of change, being more ecologically justifiable in long‐interval fire regimes and producing fewer of the negative consequences than in frequent‐fire regimes; (3) low‐risk pre‐disturbance adaptation options are few, but the most promising approaches emphasize fundamental conservation biology principles to create a safe operating space for the system to respond to change (e.g., maintaining heterogeneity across scales and minimizing stressors); and (4) post‐disturbance conditions are the primary opportunity to implement adaptation strategies (such as protecting live tree legacies and testing new regeneration methods), providing crucial learning opportunities. This approach will provide greater context and understanding of these systems for ecologists and resource managers, stimulate future development of adaptation strategies, and illustrate why public expectations for climate adaptation in these forests will differ from those for frequent‐fire forests.
Comparison of geomorphological field mapping and 2D‐InSAR mapping of periglacial landscape activity at Nordnesfjellet, northern Norway
Authors: Eckerstorfer Markus , Eriksen Harald Øverli , Rouyet Line , Christiansen Hanne H. , Lauknes Tom Rune , Blikra Lars Harald 
Published: March 2018

AbstractThe ability to continuously monitor the dynamic response of periglacial landforms in a climate change context is of increasing scientific interest. Satellite radar interferometry provides information on surface displacement that can be related to periglacial processes. Here we present a comparison of two‐dimensional (2D) surface displacement rates and geomorphological mapping at periglacial landform and sediment scale from the mountain Nordnesfjellet in northern Norway. Hence, 2D Interferometric Synthetic Aperture Radar (InSAR) results stem from a 2009–2014 TerraSAR‐X dataset from ascending and descending orbits, decomposed into horizontal displacement vectors along an east–west plane, vertical displacement vectors and combined displacement velocity. Geomorphological mapping was carried out on aerial imagery and validated in the field. This detailed landform and sediment type mapping revealed an altitudinal distribution dominated by, weathered bedrock blockfields, surrounded primarily by slightly, to non‐vegetated solifluction landforms at the mountain tops. Below, an active rockslide and associated rockfall deposits are located on the steep east‐facing side of the study area, whereas glacial sediments dominate on the gentler western side. We show that 2D InSAR correctly depicts displacement rates that can be associated with typical deformation patterns for flat‐lying or inclined landforms, within and below the regional permafrost limit, for both wet and dry areas. A net lowering of the entire landscape caused by general denudation of the periglacial landforms and sediments is here quantified for the first time using radar remote sensing. Copyright © 2018 John Wiley & Sons, Ltd.
In vivo imaging of Α7 nicotinic receptors as a novel method to monitor neuroinflammation after cerebral ischemia
Authors: Colás Lorena , Domercq Maria , Ramos‐Cabrer Pedro , Palma Ana , Gómez‐Vallejo Vanessa , Padro Daniel , Plaza‐García Sandra , Pulagam Krishna R. , Higuchi Makoto , Matute Carlos , Llop Jordi , Martín Abraham 
Published: March 2018

AbstractIn vivo positron emission tomography (PET) imaging of nicotinic acetylcholine receptors (nAChRs) is a promising tool for the imaging evaluation of neurologic and neurodegenerative diseases. However, the role of α7 nAChRs after brain diseases such as cerebral ischemia and its involvement in inflammatory reaction is still largely unknown. In vivo and ex vivo evaluation of α7 nAChRs expression after transient middle cerebral artery occlusion (MCAO) was carried out using PET imaging with [11C]NS14492 and immunohistochemistry (IHC). Pharmacological activation of α7 receptors was evaluated with magnetic resonance imaging (MRI), [18F]DPA‐714 PET, IHC, real time polymerase chain reaction (qPCR) and neurofunctional studies. In the ischemic territory, [11C]NS14492 signal and IHC showed an expression increase of α7 receptors in microglia and astrocytes after cerebral ischemia. The role played by α7 receptors on neuroinflammation was supported by the decrease of [18F]DPA‐714 binding in ischemic rats treated with the α7 agonist PHA 568487 at day 7 after MCAO. Moreover, compared with non‐treated MCAO rats, PHA‐treated ischemic rats showed a significant reduction of the cerebral infarct volumes and an improvement of the neurologic outcome. PHA treatment significantly reduced the expression of leukocyte infiltration molecules in MCAO rats and in endothelial cells after in vitro ischemia. Despite that, the activation of α7 nAChR had no influence to the blood brain barrier (BBB) permeability measured by MRI. Taken together, these results suggest that the nicotinic α7 nAChRs play a key role in the inflammatory reaction and the leukocyte recruitment following cerebral ischemia in rats.
Vestibular brain changes within 70 days of head down bed rest
Authors: Yuan Peng , Koppelmans Vincent , Reuter‐Lorenz Patricia , De Dios Yiri , Gadd Nichole , Wood Scott , Riascos Roy , Kofman Igor , Bloomberg Jacob , Mulavara Ajitkumar , Seidler Rachael 
Published: March 2018

AbstractHead‐down‐tilt bed rest (HDBR) is frequently utilized as a spaceflight analog research environment to study the effects of axial body unloading and fluid shifts that are associated with spaceflight in the absence of gravitational modifications. HDBR has been shown to result in balance changes, presumably due to sensory reweighting and adaptation processes. Here, we examined whether HDBR results in changes in the neural correlates of vestibular processing. Thirteen men participated in a 70‐day HDBR intervention; we measured balance, functional mobility, and functional brain activity in response to vestibular stimulation at 7 time points before, during, and after HDBR. Vestibular stimulation was administered by means of skull taps, resulting in activation of the vestibular cortex and deactivation of the cerebellar, motor, and somatosensory cortices. Activation in the bilateral insular cortex, part of the vestibular network, gradually increased across the course of HDBR, suggesting an upregulation of vestibular inputs in response to the reduced somatosensory inputs experienced during bed rest. Furthermore, greater increase of activation in multiple frontal, parietal, and occipital regions in response to vestibular stimulation during HDBR was associated with greater decrements in balance and mobility from before to after HDBR, suggesting reduced neural efficiency. These findings shed light on neuroplastic changes occurring with conditions of altered sensory inputs, and reveal the potential for central vestibular‐somatosensory convergence and reweighting with bed rest.
Presurgical language fMRI: Clinical practices and patient outcomes in epilepsy surgical planning
Authors: Benjamin Christopher F. A. , Li Alexa X. , Blumenfeld Hal , Constable R. Todd , Alkawadri Rafeed , Bickel Stephan , Helmstaedter Christoph , Meletti Stefano , Bronen Richard , Warfield Simon K. , Peters Jurriaan M. , Reutens David , Połczyńska Monika , Spencer Dennis D. , Hirsch Lawrence J. 
Published: March 2018

AbstractThe goal of this study was to document current clinical practice and report patient outcomes in presurgical language functional MRI (fMRI) for epilepsy surgery. Epilepsy surgical programs worldwide were surveyed as to the utility, implementation, and efficacy of language fMRI in the clinic; 82 programs responded. Respondents were predominantly US (61%) academic programs (85%), and evaluated adults (44%), adults and children (40%), or children only (16%). Nearly all (96%) reported using language fMRI. Surprisingly, fMRI is used to guide surgical margins (44% of programs) as well as lateralize language (100%). Sites using fMRI for localization most often use a distance margin around activation of 10mm. While considered useful, 56% of programs reported at least one instance of disagreement with other measures. Direct brain stimulation typically confirmed fMRI findings (74%) when guiding margins, but instances of unpredicted decline were reported by 17% of programs and 54% reported unexpected preservation of function. Programs reporting unexpected decline did not clearly differ from those which did not. Clinicians using fMRI to guide surgical margins do not typically map known language‐critical areas beyond Broca's and Wernicke's. This initial data shows many clinical teams are confident using fMRI not only for language lateralization but also to guide surgical margins. Reported cases of unexpected language preservation when fMRI activation is resected, and cases of language decline when it is not, emphasize a critical need for further validation. Comprehensive studies comparing commonly‐used fMRI paradigms to predict stimulation mapping and post‐surgical language decline remain of high importance.
Impaired rich club and increased local connectivity in children with traumatic brain injury: Local support for the rich?
Authors: Verhelst Helena , Vander Linden Catharine , De Pauw Toon , Vingerhoets Guy , Caeyenberghs Karen 
Published: March 2018

AbstractRecent evidence has shown the presence of a “rich club” in the brain, which constitutes a core network of highly interconnected and spatially distributed brain regions, important for high‐order cognitive processes. This study aimed to map the rich club organization in 17 young patients with moderate to severe TBI (15.71 ± 1.75 years) in the chronic stage of recovery and 17 age‐ and gender‐matched controls. Probabilistic tractography was performed on diffusion weighted imaging data to construct the edges of the structural connectomes using number of streamlines as edge weight. In addition, the whole‐brain network was divided into a rich club network, a local network and a feeder network connecting the latter two. Functional outcome was measured with a parent questionnaire for executive functioning. Our results revealed a significantly decreased rich club organization (p values < .05) and impaired executive functioning (p < .001) in young patients with TBI compared with controls. Specifically, we observed reduced density values in all three subnetworks (p values < .005) and a reduced mean strength in the rich club network (p = .013) together with an increased mean strength in the local network (p = .002) in patients with TBI. This study provides new insights into the nature of TBI‐induced brain network alterations and supports the hypothesis that the local subnetwork tries to compensate for the biologically costly subnetwork of rich club nodes after TBI.
The effect of biological soil crusts on soil moisture dynamics under different rainfall conditions in the Tengger Desert, China
Authors: Shi Wei , Wang Xin‐ping , Zhang Ya‐feng , Pan Yan‐xia , Hu Rui , Jin Yan‐xia 
Published: March 2018

AbstractRainfall is considered as the dominant water replenishment in desert ecosystems, and the conversion of rainfall into soil water availability plays a central role in sustaining the ecosystem function. In this study, the role of biological soil crusts (BSCs), typically formed in the revegetated desert ecosystem in the Tengger Desert of China, in converting rainfall into soil water, especially for the underlying soil moisture dynamics, was clarified by taking into account the synthetic effects of BSCs, rainfall characteristics, and antecedent soil water content on natural rainfall conditions at point scale. Our results showed that BSCs retard the infiltration process due to its higher water holding capacity during the initial stage of infiltration, such negative effect could be offset by the initial wet condition of BSCs. The influence of BSCs on infiltration amount was dependent on rainfall regime and soil depth. BSCs promoted a higher infiltration through the way of prolonged water containing duration in the ground surface and exhibited a lower infiltration at deep soil layer, which were much more obvious under small and medium rainfall events for the BSCs area compared with the sand area. Generally, the higher infiltration at top soil layer only increased soil moisture at 0.03 m depth; in consequence, there was no water recharge for the deep soil, and thus, BSCs had a negative effect on soil water effectiveness, which may be a potential challenge for the sustainability of the local deep‐rooted vegetation under the site specific rainfall conditions in northwestern China.
Serum DHEA and Its Sulfate Are Associated With Incident Fall Risk in Older Men: The MrOS Sweden Study
Authors: Ohlsson Claes , Nethander Maria , Karlsson Magnus K , Rosengren Björn E , Ribom Eva , Mellström Dan , Vandenput Liesbeth 
Published: March 2018

ABSTRACT

The adrenal-derived hormones dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are the most abundant circulating hormones and their levels decline substantially with age. Many of the actions of DHEAS are considered to be mediated through metabolism into androgens and estrogens in peripheral target tissues. The predictive value of serum DHEA and DHEAS for the likelihood of falling is unknown. The aim of this study was, therefore, to assess the associations between baseline DHEA and DHEAS levels and incident fall risk in a large cohort of older men. Serum DHEA and DHEAS levels were analyzed with mass spectrometry in the population-based Osteoporotic Fractures in Men study in Sweden (n = 2516, age 69 to 81 years). Falls were ascertained every 4 months by mailed questionnaires. Associations between steroid hormones and falls were estimated by generalized estimating equations. During a mean follow-up of 2.7 years, 968 (38.5%) participants experienced a fall. High serum levels of both DHEA (odds ratio [OR] per SD increase 0.85; 95% CI, 0.78 to 0.92) and DHEAS (OR 0.88, 95% CI, 0.81 to 0.95) were associated with a lower incident fall risk in models adjusted for age, BMI, and prevalent falls. Further adjustment for serum sex steroids or age-related comorbidities only marginally attenuated the associations between DHEA or DHEAS and the likelihood of falling. Moreover, the point estimates for DHEA and DHEAS were only slightly reduced after adjustment for lean mass and/or grip strength. Also, the addition of the narrow walk test did not substantially alter the associations between serum DHEA or DHEAS and fall risk. Finally, the association with incident fall risk remained significant for DHEA but not for DHEAS after simultaneous adjustment for lean mass, grip strength, and the narrow walk test. This suggests that the associations between DHEA and DHEAS and falls are only partially mediated via muscle mass, muscle strength, and/or balance. In conclusion, older men with high DHEA or DHEAS levels have a lesser likelihood of a fall. © 2018 American Society for Bone and Mineral Research.
“She's woke”: The paradoxical effects of the 2016 election on an individual client
Authors: Raskin Patricia M. 
Published: March 2018

AbstractThe purpose of this article is to present a case history of an individual client deeply affected by the 2016 election of Donald Trump: an unexpected key to her self‐empowerment. Raised in poverty and with a history of being sexually abused, the client's anger and frustration at Hillary Clinton's loss in the election led to an examination in therapy of the role of gender in her life and enabled her to strengthen her sense of agency in her world.
Impact of the 2016 US presidential election on OCD symptom presentation: A case illustration
Authors: Davis Michelle L. , McCann Matthew , Goodman Wayne K. , Storch Eric A. 
Published: March 2018

AbstractA recent survey of Americans found that the majority experienced stress during and after the 2016 United States presidential election. Psychosocial, environmental stressors can have a unique impact on symptom presentation in mental health disorders. This manuscript details a case illustration of an individual whose symptoms of obsessive‐compulsive disorder were directly linked to the election, as well as how these symptoms were addressed via treatment with intensive exposure and response prevention.