bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term clinical outcome of the Charité III total lumbar disc replacement
Authors: Kitzen J. , Schotanus M. G. M. , van Kuijk S. M. J. , Jutten E. M. C. , Kort N. P. , van Rhijn L. W. , Willems P. C.
Published: January 2020

Purpose

To compare the long-term clinical results and complications of two revision strategies for patients with failed total disc replacements (TDRs).

Methods

In 19 patients, the TDR was removed and the intervertebral defect was filled with a femoral head bone strut graft. In addition, instrumented posterolateral fusion was performed (removal group). In 36 patients, only a posterolateral instrumented fusion was performed (fusion group). Visual analogue scale (VAS) for pain and Oswestry Disability Index (ODI) were completed pre- and post-revision surgery. Intra- and post-operative complications of both revision strategies were assessed.

Results

The median follow-up was 12.3 years (range 5.3–24.3). In both the removal and fusion group, a similar (p = 0.515 and p = 0419, respectively) but significant decrease in VAS- (p = 0.001 and p = 0.001, respectively) and ODI-score (p = 0.033 and p = 0.013, respectively) at post-revision surgery compared to pre-revision surgery was seen. A clinically relevant improvement in VAS- and ODI-score was found in 62.5% and 43.8% in the removal group and in 43.5% and 39.1% in the fusion group (p = 0.242 and p = 0.773, respectively). Removal of the TDR was associated with substantial intra-operative complications such as major vessel bleeding and ureter lesion. The percentage of late reoperations for complications such as pseudarthrosis was comparable for both revision strategies.

Conclusions

Revision of a failed TDR is clinically beneficial in about half of the patients. No clear benefits for additional TDR removal as compared to posterolateral instrumented fusion alone could be identified. Particularly, when considering the substantial risks and complications, great caution is warranted with removal of the TDR.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.
On longitudinal electromagnetic stirring in the continuous casting of steel blooms
Authors: Nick A. S. , Vynnycky M.
Published: January 2020

Recent work highlighting an anomaly in the modelling of rotary electromagnetic stirring (EMS) in the continuous casting of round steel billets is extended to the case of longitudinal stirring for rectangular blooms. An earlier, still often-cited, model forms the basis of the current analysis, which uses asymptotic methods on the three-dimensional (3D) Maxwell equations and demonstrates how the earlier result for the components of the Lorentz force is but a particular case of a more general form. Time-dependent 3D computations using finite-element methods are also performed to verify the validity of the asymptotic analysis, and the relevance of the results to modulated EMS is noted.
Lagrangian Averaged Stochastic Advection by Lie Transport for Fluids
Authors: Drivas Theodore D. , Holm Darryl D. , Leahy James-Michael
Published: January 2020

We formulate a class of stochastic partial differential equations based on Kelvin’s circulation theorem for ideal fluids. In these models, the velocity field is randomly transported by white-noise vector fields, as well as by its own average over realizations of this noise. We call these systems the Lagrangian averaged stochastic advection by Lie transport (LA SALT) equations. These equations are nonlinear and non-local, in both physical and probability space. Before taking this average, the equations recover the Stochastic Advection by Lie Transport (SALT) fluid equations introduced by Holm (Proc R Soc A 471(2176):20140963, 2015). Remarkably, the introduction of the non-locality in probability space in the form of momentum transported by its own mean velocity gives rise to a closed equation for the expectation field which comprises Navier–Stokes equations with Lie–Laplacian ‘dissipation’. As such, this form of non-locality provides a regularization mechanism. The formalism we develop is closely connected to the stochastic Weber velocity framework of Constantin and Iyer (Commun Pure Appl Math 61(3):330–345, 2008) in the case when the noise correlates are taken to be the constant basis vectors in $$\mathbb {R}^3$$

R

3

and, thus, the Lie–Laplacian reduces to the usual Laplacian. We extend this class of equations to allow for advected quantities to be present and affect the flow through exchange of kinetic and potential energies. The statistics of the solutions for the LA SALT fluid equations are found to be changing dynamically due to an array of intricate correlations among the physical variables. The statistical properties of the LA SALT physical variables propagate as local evolutionary equations which when spatially integrated become dynamical equations for the variances of the fluctuations. Essentially, the LA SALT theory is a non-equilibrium stochastic linear response theory for fluctuations in SALT fluids with advected quantities.
CO2 mineralization by burnt oil shale and cement bypass dust: effect of operating temperature and pre-treatment
Authors: Yörük Can Rüstü , Uibu Mai , Usta Mustafa Cem , Kaljuvee Tiit , Trikkel Andres
Published: January 2020

The alkaline wastes such as burnt oil shale (BOS) and cement bypass dust (BPD) generally contain free lime and portlandite which make them suitable sorbent materials for CO2 trapping via mineral carbonation technique of carbon capture and sequestration. In order to study the reaction kinetics and effect of operating parameters on carbonation processes of such alkaline wastes for future industrial sized scale-ups, as well as to identify the effects on carbonation capacity when these sorbents undergo pre-treatment and are exposed to different temperatures, BOS and BPD as sorbents in CO2 mineralization process have been investigated with thermal analysis methods in the current work. Results indicate that selected types of BOS and BPD could be used as binders in the CO2 mineralization systems, binding reasonably good amount of CO2 already in the early stage of the carbonation process which later slows down as the rate of CaO carbonation becomes mainly diffusion controlled. Increased process temperature and hydration as pre-treatment improve the CO2 binding ability, while the effect of milling has been found to be staggering and not as significant as the effect of hydration and temperature rise. The appropriate kinetic mechanism functions were determined, and the kinetic parameters—activation energy (Ea) and pre-exponential factor (A) values were calculated for all the samples. The Ea values of hydrated samples are lower for BOS samples compared to non-hydrated samples. It was shown that activation by hydration enables to reach the same CO2 uptake levels at lower temperatures, thereby making the mineralization process more energy efficient and thus lowering the costs.
Sustaining Programs: Lessons Learned from Former Federal Grantees
Authors: Warner Alexandra , Bennett Nicole , Asheer Subuhi , Alamillo Julia , Keating Betsy , Knab Jean
Published: January 2020

Introduction

A common concern of federal funders and grant recipients is how to sustain program activities once their federal funding period ends. Federal funding can be intended to develop or seed a program but not necessarily to continue its activities indefinitely. Understanding the importance of programmatic sustainability, the Office of Population Affairs (OPA) conducted research in 2015 on the elements that contribute to sustainability. As part of the Sustainability Study, OPA collected information from former Pregnancy Assistance Fund (PAF) program grantees.

Methods

Grantees that were awarded cohort 1 PAF program funding (2010–2014) but not awarded cohort 2 funding (2014–2017) were eligible for study inclusion because their OPA funding ended more than 1 year prior to the Sustainability Study, allowing for an assessment of sustainability after federal funding. Seven former PAF grantees were identified as eligible. Interviews were conducted with six of these grantees; grant applications and interim final reports from all seven were reviewed.

Results

Five lessons emerged from interviews and review of grant documentation. Programs successfully continuing beyond the federal grant period tended to (1) diversify funding sources, (2) communicate regularly with key stakeholders, (3) form partnerships with like-minded programs, (4) consider implementing evidence-based interventions, and (5) begin planning for sustainability early.

Discussion

By considering these lessons learned from the research, grantees can be well positioned to continue beyond a federal grant period. The lessons garnered from the Sustainability Study have informed, expanded, and affirmed OPA’s sustainability toolkit, sustainability framework, and technical assistance.
Resilienz – Geschichte, Modelle und Anwendung
Authors: Thun-Hohenstein Leonhard , Lampert Kerstin , Altendorfer-Kling Ulrike
Published: January 2020

In diesem Beitrag der Zeitschrift für Psychodrama und Soziometrie wird der Begriff der Resilienz beschrieben, eine zusammenfassende Definition gegeben und seine Anwendung dargestellt. Es werden die Resilienzfaktoren und verschiedene Modelle mit dem Versuch, eine vereinheitlichte Zusammenschau zu geben, beschrieben. Auf die Nutzung des Resilienzbegriffes im Psychodrama wird ebenfalls eingegangen. Zuletzt wird auch eine kritische Sichtweise auf die Anwendung des Modells in die Diskussion einbezogen.
Topographic and lithologic controls behind mountain depopulation in Zlatibor District (Western Serbia)
Authors: Telbisz Tamás , Brankov Jovana , Ćalić Jelena
Published: January 2020

Mountain depopulation is a worldwide phenomenon observed in all continents. It has varied socio-economic reasons; among others, the low profitability of traditional agriculture, the better job possibilities and the higher level of services in urban settlements. However, it is often recognized that depopulation is related to natural factors such as elevation, slope or lithology. It is also observed that protected areas are frequently established in depopulated mountain regions. Their primary aim is the conservation of nature, but they may help tourism development as well. Tourism, in turn, may slow down or even reverse the process of depopulation. In this study, we investigate the impact of topographic and lithologic factors, namely of karst settings, on mountain demographic processes and the relationship of protected areas and tourism through the example of the northern part of Zlatibor District (Western Serbia). The study area is characterized by mountains and hills at elevations from 200 to 1600 m a.s.l. Our aim is to find GIS-based statistical relationships between topographic, lithologic factors and demographic characteristics. In this area, mountain depopulation started after WWII, and we proved that this process was strongly controlled by topographic factors. The higher and more dissected the area, the more significant is the decrease of the population and the more advanced is the ageing. As a result, population density contrasts are much more pronounced now than 70 years ago. After WWII, depopulation and ageing became gradually more serious on karstic terrains than on non-karst. However, by using compound topographic and lithologic types, we proved that it is not the effect of karst, but the effect of topography. The flow of population from hills and mountains to valleys and basins are closely related to the restructuring of the economic sectors. At present, for the study area, the development of tourism is unequivocally nature-based and connected to protected areas, namely to Tara National Park, Zlatibor Nature Park and Šargan-Mokra Gora Nature Park. In this paper, we also demonstrate how lithology influences tourism possibilities. The leading role of Zlatibor in tourism development is largely thanks to its favourable position on a main transit route.
Victimized State and Visionary Leader? Questioning China’s Approach to Human Security in Africa
Authors: Hwang Yih-Jye , Black Lindsay
Published: January 2020

Over the past decades, numerous critiques have emerged of China’s policy towards Africa. These critiques perceive China as a mercantilist or neocolonial power seeking to dominate the African continent through land grabs, exploitative trade deals, and resource extraction. These critiques do however not consider how the Chinese government has attempted to justify its aid policy towards Africa in ways that claim to secure human beings. Though the Chinese government has not officially adopted the concept of human security, it has engaged with the concept and developed its own interpretation of how human beings should be secured. This interpretation is based on the depiction of China as a state victimized through imperialism that has emerged in the twenty-first century as a global power with visionary ideas. Accordingly, Chinese policymakers believe they can offer an alternative model to Western interventions, imposition of neoliberal economic doctrine, and emphasis on democratization and human rights. In Africa, though China’s vision has generated benefits for some, it has also victimized others. China needs to critically reflect on and adapt its developmental vision if it truly intends to help human beings overcome the myriad challenges they face in their daily lives.
Worth the Weight? Recent Trends in Obstetric Practices, Gestational Age, and Birth Weight in the United States
Authors: Tilstra Andrea M. , Masters Ryan K.
Published: January 2020

Birth weight in the United States declined substantially during the 1990s and 2000s. We suggest that the declines were likely due to shifts in gestational age resulting from changes in obstetric practices. Using restricted National Vital Statistics System data linked birth/infant death data for 1990–2013, we analyze trends in obstetric practices, gestational age distributions, and birth weights among first-birth singletons born to U.S. non-Hispanic White, non-Hispanic Black, and Latina women. We use life table techniques to analyze the joint probabilities of gestational age-specific birth and gestational age-specific obstetric intervention (i.e., induced cesarean delivery, induced vaginal delivery, not-induced cesarean delivery, and not-induced vaginal delivery) to fully document trends in obstetric practices by gestational age. We use simulation techniques to estimate counterfactual changes in birth weight distributions if obstetric practices did not change between 1990 and 2013. Results show that between 1990 and 2013, the likelihood of induced labors and cesarean deliveries increased at all gestational ages, and the gestational age distribution of U.S. births significantly shifted. Births became much less likely to occur beyond gestational week 40 and much more likely to occur during weeks 37–39. Overall, nearly 18% of births from not-induced labor and vaginal delivery at later gestational ages were replaced with births occurring at earlier gestational ages from obstetric interventions. Results suggest that if rates of obstetric practices had not changed between 1990 and 2013, then the average U.S. birth weight would have increased over this time. Findings strongly indicate that recent declines in U.S. birth weight were due to increases in induced labor and cesarean delivery at select gestational ages.
Genetic and taxonomic assessment of the widespread Afrotropical ambrosia beetle Xyleborus principalis (Coleoptera, Scolytinae)
Authors: Jordal Bjarte , Tischer Marta
Published: January 2020

The taxonomy of the widespread Afrotropical ambrosia beetleXyleborus principalisEichhoff, 1878 is reviewed based on morphological and molecular data. The species is both morphologically and genetically variable but without any structure corresponding to geography, or between genes and morphology. Examination of type material and other specimens collected across Africa and Madagascar documented the existence of a single species. New synonymies are proposed forXyleborus principalis(=X. alluaudiSchaufuss, 1897, =X. camerunusHagedorn, 1910, =X. consobrinusEggers, 1932, =X. discrepansSchedl, 1950, =X. annectensSchedl, 1957, =X. peramploidesSchedl, 1957).
Powassan Virus in a Hunter Returning from a Trip in the Adirondack Park
Authors: Colman David , Peaslee Samuel
Published: January 2020

Powassan virus is a rare flavivirus that may be transmitted by tick bite and is associated with encephalitis. Infections have been described in the northern United States, Canada, and Russia. We present the case of a 56-y-old man who presented to our hospital with symptoms of confusion, altered behavior, and headache. The patient developed fever and status epilepticus despite supportive care and required endotracheal intubation. Six days before presentation, the patient had returned from a hunting trip in the Adirondack region of New York State.
Implications of Alternative Crop Insurance Subsidies
Authors: Maisashvili Aleksandre , Bryant Henry L. , Jones Jason P.H.
Published: January 2020

In this research, we analyze the economic effects across various crop insurance subsidy and policy scenarios to determine producer insurance choice response, total premium and subsidy payments and study their economic implications on dryland corn, soybean, and winter wheat producers. We rely on the expected utility maximization framework to rank policy combination sets that are available to a typical producer to analyze the impacts of crop insurance subsidy changes and elimination of certain insurance policies across the three crops. Several scenarios were analyzed across subsidy and policy options and were found to have noticeably different farmer behavioral responses and economic implications.
The forgotten exotic tapeworms: a review of uncommon zoonotic Cyclophyllidea
Authors: Sapp Sarah G. H. , Bradbury Richard S.
Published: January 2020

As training in helminthology has declined in the medical microbiology curriculum, many rare species of zoonotic cestodes have fallen into obscurity. Even among specialist practitioners, knowledge of human intestinal cestode infections is often limited to three genera,Taenia,HymenolepisandDibothriocephalus. However, five genera of uncommonly encountered zoonotic Cyclophyllidea (Bertiella,Dipylidium,Raillietina,InermicapsiferandMesocestoides) may also cause patent intestinal infections in humans worldwide. Due to the limited availability of summarized and taxonomically accurate data, such cases may present a diagnostic dilemma to clinicians and laboratories alike. In this review, historical literature on these cestodes is synthesized and knowledge gaps are highlighted. Clinically relevant taxonomy, nomenclature, life cycles, morphology of human-infecting species are discussed and clarified, along with the clinical presentation, diagnostic features and molecular advances, where available. Due to the limited awareness of these agents and identifying features, it is difficult to assess the true incidence of these ‘forgotten’ cestodiases as clinical misidentifications are likely to occur. Also, the taxonomic status of many of the human-infecting species of these tapeworms is unclear, hampering accurate species identification. Further studies combining molecular data and morphological observations are necessary to resolve these long-standing taxonomic issues and to elucidate other unknown aspects of transmission and ecology.
Tradition and Innovation in Copper Age Metallurgy: Results of a Metallographic Examination of Flat Axes from Eastern Central Europe and the Carpathian Basin
Authors: Kienlin Tobias L.
Published: January 2020

In this paper an attempt is made to integrate discussions on social and technological aspects of Copper Age metallurgy. The South-east European Copper Age is widely held to be characterised by newly emerging elites and a strong societal impact of metallurgy. It is shown that much of this discussion is influenced by the evidence of the exceptionally rich Varna cemetery in Bulgaria. This is not a suitable model for Copper Age social structure in general because Varna is an extremely short-lived phenomenon and may reflect aspects of culture and identity other than our search for social elites implies. In any case there is no comparable evidence throughout the rest of Copper Age Europe. In the Carpathian basin, for example, Copper Age society certainly did not know permanent hierarchies, centralised control over dispersed settlements units, or distinctions in personal identity other than age and gender. Against this background metallographic data are used to establish the state of knowledge of Copper Age metalworkers. There are similarities in overall approach, yet within this broad tradition two distinct horizons of metallurgical knowledge and practice can be distinguished. The reasons of the differences observed in casting technique and forging are discussed. Drawing on ethnographic data a model is presented to account for uniformity in the basic parameters on the one hand and the spread of innovations in Middle to Late Copper Age society on the other without social elites being in control of raw materials, metalworking, and exchange.
Ritual Structures in South Scandinavian Prehistory
Authors: Larsson Lars
Published: January 2020

An increasing number of buildings are coming to light on prehistoric sites in Scandinavia that seem to be related to ritual, cult, or religious activities. This paper documents examples of such buildings from the Mesolithic to the Viking Period. The Late Meolithic cemetery at Skateholm provides evidence for structures associated with materials only otherwise found in grave contexts. Certain aspects of Early Neolithic long barrows and palisaded enclosures may infer ritual practices not directly of a funerary nature. The later Neolithic was marked in the cultural groupings of various regions by the construction of palisaded enclosures, wooden structures associated with graves, or pile dwellings, each often associated with a rich finds assemblage and frequent evidence for burning. These structures and their contents show obvious distinctions from the contemporary domestic settlement and burial sites with which they were associated. Bronze Age examples include rectangular stone walled and D- and C-shaped wooden structures placed beside burial areas and facing cairns. The latter forms continue into the Iron Age, for which few other clear examples of ritual structures are apparent, in spite of historical references. Those that have been identified seem to be associated with important central places. The site of Uppåkra, in southernmost Sweden, has produced an unusual small building set beside a hall around and within which were deposited hundreds of weapons and gold and glass objects. This relationship bears a striking resemblance to the description of the hall of Wodan at Valhalla in Norse mythology.
An Early Neolithic Grave and Occupation, and an Early Bronze Age Hearth on the Thames Foreshore at Yabsley Street, Blackwall, London
Authors: Coles Sarah , Ford Steve , Taylor Andy , Anthony Sian , Gale Rowena , Keith-Lucas Michael , Raymond Frances , Robinson Mark , Vince Alan
Published: January 2020

Excavation on the Thames floodplain in London revealed traces of Early Neolithic occupation and burial on a sand and gravel bar beneath alluvium. A large expanse of peat also buried by alluvium was recorded between these finds and the modern river Thames suggesting that the occupation was situated on or close to the foreshore. A single grave cut into the natural sand contained a poorly preserved crouched inhumation, possibly of a woman. The burial was accompanied by a fragment of carinated bowl, a flint knife, and other struck flints. A radiocarbon date from an oak retaining plank within the grave of 5252±28 BP (4220–3970 cal BC: KIA20157) makes this burial one of the earliest from the British Isles and the earliest known for London. A scatter of struck flint and pottery predominantly of Early Neolithic date was recovered from adjacent areas of the sand. A nearby hearth contained fragments of Early Bronze Age pottery pointing to later prehistoric activity nearby.

Charred plant remains indicate both the collection of wild plant foods and cultivated cereals in the Early Neolithic. Radiocarbon dating of the adjacent peat deposits indicated their rapid growth within the Middle Bronze Age with a marked decline in woodland cover at the start of the sequence and a rise in grassland and herb species. Cereal pollen then briefly became a significant component of the sequence before declining to more modest levels.
Neolithic Causewayed Enclosures and Later Prehistoric Farming: Duality, Imposition and the Role of Predecessors at Kingsborough, Isle of Sheppey, Kent, UK
Authors: Allen Michael J. , Leivers Matt , Ellis Chris , Stevens Simon , Clelland Susan , Bayliss Alex , Butler Chris , Gale Rowena , Gibson Alex , McKinley Jacqueline I. , Knight Stephanie , Mepham Lorraine , Scaife Robert , Stevens Chris J.
Published: January 2020

Developer-funded archaeology on the Isle of Sheppey resulted in the discovery of not one but two Neolithic causewayed enclosures on the same hilltop in very close (c. 300 m) proximity. In the later Bronze Age enclosures and cremation cemeteries were constructed immediately to the east, followed by Iron Age enclosures and, ultimately, field systems dating to the later Iron Age onwards.

A radiocarbon programme enabled the chronological sequence and hiatus between all of these events to be discerned, but the majority of this paper explores the physical, chronological, and social relationship between the two Neolithic causewayed enclosures. These were of different forms and, although on the same hilltop, they each seem to have had distinctly different viewsheds over the Thames and the Swale respectively. There are subtle, but potentially significant, differences in the material culture and deposition which allow exploration of the possible functions and role(s) of the two largely contemporaneous sites. Questions may be addressed such as whether they performed the same functions for two communities or had separate and distinct roles for a single community. Beyond the Neolithic, the paper also explores the nature of the later use of the hilltop. The Bronze Age enclosures, though agricultural in function, clearly seem to respect their Neolithic predecessors invoking a remembrance of space, which is lost by the Iron Age. The shift away from the special function of this landscape in the Neolithic to a subsequent agricultural use is explored, as is the hiatus in use and subsequent re-use of the area.
Politics of Scale, Bargaining Power and Its Spatial Impacts: Planning for Intercity Railways in the Pearl River Delta, China
Authors: Zhang Mengmeng , Xu Jiang , Chung Calvin King Lam
Published: January 2020

The recent proliferation of China's railways has posed challenges to the dominance of the national-level railway authority on railway development. Since the 2000s, the planning of new railways has evolved into a politics of scale in which actors across multiple scales of government have bargained over railway alignment and station siting for their respective interests. This politics is shaped by the uneven bargaining powers of the contending state agents over railway planning. Interscalar division of regulatory oversight over strategic resources for railway development enables state agents at some scales to bargain more successfully, whereas variations in administrative and economic standing further differentiate the interscalar bargaining powers of municipal governments. Different results of bargaining across scales for each city have produced, as intercity railway planning in the Pearl River Delta illustrates, significant intercity variations in average travel times to the stations for the new railways that these cities share. Owing to the peculiar scalar distribution of the costs and benefits of the new railways, municipal governments with greater bargaining power have, contrary to traditional wisdom, bargained for less accessibility to intercity railway stations.
Oscillatory brain dynamics of pronoun processing in native Spanish speakers and in late second language learners of Spanish
Authors: Rossi Eleonora , Prystauka Yanina
Published: January 2020

A longstanding question in the second language acquisition literature is whether late second language (L2) learners process grammatical structures in a native-like manner. Here, we use Time Frequency Representation (TFR) analysis to test morpho-syntactic processing of clitic pronouns in native and late L2 learners of Spanish. The TFR results show overall similar power decreases in theta, alpha, and beta frequencies in both groups. Critically, the observed oscillatory effects persisted in time for native Spanish speakers, but declined earlier for L2 learners. We discuss the results using cell-assembly theory models for language processing (e.g., Pulvermüller, 1999) that posit a biphasic time-course for neural assemblies consisting of an early ignition (recognition) and a later reverberation (re-processing) phase. We propose a working hypothesis for L2 processing in tune with a cell-assembly theory suggesting that the length of the reverberation phase could be a distinguishing feature between native and L2 processing.
LYAPUNOV-TYPE INEQUALITY FOR EXTREMAL PUCCI’S EQUATIONS
Authors: TYAGI J. , VERMA R. B.
Published: January 2020

In this article, we establish a Lyapunov-type inequality for the following extremal Pucci’s equation:$$\begin{eqnarray}\left\{\begin{array}{@{}ll@{}}{\mathcal{M}}_{\unicode[STIX]{x1D706},\unicode[STIX]{x1D6EC}}^{+}(D^{2}u)+b(x)|Du|+a(x)u=0 & \text{in}~\unicode[STIX]{x1D6FA},\\ u=0 & \text{on}~\unicode[STIX]{x2202}\unicode[STIX]{x1D6FA},\end{array}\right.\end{eqnarray}$$where$\unicode[STIX]{x1D6FA}$is a smooth bounded domain in$\mathbb{R}^{N}$,$N\geq 2$. This work generalizes the well-known works on the Lyapunov inequality for extremal Pucci’s equations with gradient nonlinearity.
Association of depression and diabetes complications and mortality: a population-based cohort study
Authors: Wu C.-S. , Hsu L.-Y. , Wang S.-H.
Published: January 2020

Aims

Several studies suggested that depression might worsen the clinical outcome of diabetes mellitus; however, such association was confounded by duration of illness and baseline complications. This study aimed to assess whether depression increases the risk of diabetes complications and mortality among incident patients with diabetes.

Methods

This was a population-based matched cohort study using Taiwan's National Health Insurance Research Database. A total of 38 537 incident patients with diabetes who had depressive disorders and 154 148 incident diabetes patients without depression who were matched by age, sex and cohort entry year were randomly selected. The study endpoint was the development of macrovascular and microvascular complications, all-cause mortality and cause-specific mortality.

Results

Among participants, the mean (±SD) age was 52.61 (±12.45) years, and 39.63% were male. The average duration of follow-up for mortality was 5.5 years, ranging from 0 to 14 years. The adjusted hazard ratios were 1.35 (95% confidence interval [CI], 1.32–1.37) for macrovascular complications and 1.08 (95% CI, 1.04–1.12) for all-cause mortality. However, there was no association of depression with microvascular complications, mortality due to cardiovascular diseases or mortality due to diabetes mellitus. The effect of depression on diabetes complications and mortality was more prominent among young adults than among middle-aged and older adults.

Conclusions

Depression was associated with macrovascular complications and all-cause mortality in our patient cohort. However, the magnitude of association was less than that in previous studies. Further research should focus on the benefits and risks of treatment for depression on diabetes outcome.
The Impact of an Intense Cyclone on Short‐Term Sea Ice Loss in a Fully Coupled Atmosphere‐Ocean‐Ice Model
Authors: Stern Daniel P. , Doyle James D. , Barton Neil P. , Finocchio Peter M. , Komaromi William A. , Metzger E. Joseph
Published: January 2020

Arctic cyclones may be associated with periods of locally enhanced sea ice loss during the summer, and some studies have found that an intense cyclone in August 2012 resulted in a rapid sea ice retreat. This study uses a coupled atmosphere‐ocean‐ice model (Navy‐ESPC) to explore the relationship between the 2012 cyclone and short‐term sea ice melting. There are two mechanisms of cyclone‐induced melting in Navy‐ESPC: turbulent mixing of a warm layer located at 15‐ to 35‐m depth increases bottom melting and warm air advection by the strong surface winds increases surface melting. Although the rate of sea ice melt is substantially increased in association with the cyclone, this effect is confined to a relatively small region and only lasts for a few days. There is no clear signature of the cyclone on the overall Arctic sea ice extent in Navy‐ESPC.
Untangling El Niño‐La Niña Asymmetries Using a Nonlinear Coupled Dynamic Index
Authors: Kim Soong‐Ki , An Soon‐Il
Published: January 2020

The linear recharge oscillator model for the El Niño–Southern Oscillation (ENSO) was expanded to a nonlinear model, thus allowing identification of a nonlinear dynamic ENSO index. This index was applied for a dynamic examination of the El Niño‐La Niña asymmetry. Here, the nonlinear physical processes including the nonlinear dynamical heating were implemented into the linear recharge oscillator model in the form of quadratic nonlinearity. This nonlinear recharge oscillator model revealed that nonlinear (linear) physical processes play a critical role in the long‐term ENSO skewness (amplitude) changes quantitatively. Particularly, the large part of the long‐term ENSO skewness change could be explained by the quadratic nonlinearity associated with the nonlinear ocean dynamical heating, which is closely related to change in mean thermocline. This research provides a unified framework to understand better the past‐present‐future ENSO changes by applying the interdecadal change dynamics on a low hierarchical level.
The Southern Zagros Collisional Orogen: New Insights From Transdimensional Trees Inversion of Seismic Noise
Authors: Pilia S. , Jackson J. A. , Hawkins R. , Kaviani A. , Ali M. Y.
Published: January 2020

Imaging and resolving the lateral continuity of 3‐D crustal structures enhance our ability to interpret seismicity and to understand how orogens are created. We apply a Bayesian, hierarchical inversion approach based on a transdimensional trees‐structured wavelet parameterization to recover phase velocity maps at 2–40 s periods. We then invert phase velocity dispersion to constrain a 3‐D shear velocity model of the crust beneath south‐central Iran. Together with accurate earthquake centroid depths and focal mechanisms, the pattern of 3‐D velocity variations supports recent suggestions that most large earthquakes in the Zagros occur within the lower sedimentary cover or close to the sediment‐basement interface. Furthermore, we find evidence for Arabian basement underthrusting beneath central Iran, although only in one location does it appear to generate earthquakes. Our new 3‐D tomographic model clarifies and throws new light on the crustal structure of the SE Zagros and its relation to seismicity and active faulting.
Rapid Formation of Clathrate Hydrate From Liquid Ethane and Water Ice on Titan
Authors: Vu T. H. , Choukroun M. , Sotin C. , Muñoz‐Iglesias V. , Maynard‐Casely H. E.
Published: January 2020

Liquid ethane is present in the lakes and seas observed on Titan's surface by the Cassini‐Huygens mission. While interaction between liquid hydrocarbons and water ice is expected to result in the formation of clathrate hydrates, such reaction (and its kinetics) has not yet been demonstrated for cryogenic liquids under relevant planetary conditions. In this paper, we report the first experimental evidence for rapid formation of clathrates upon direct contact of liquid ethane with water ice at 1 bar using micro‐Raman spectroscopy. Kinetics experiments conducted in the temperature range 150–173 K yield an activation energy of 14.8 ± 2.2 kJ/mol, which is suggestive of a diffusion‐controlled mechanism for clathrate formation. This implies that a clathrate reservoir can form within seasonal time scales on Titan if liquid ethane comes into contact with a pre‐existing icy bedrock, which may hold important implications for the structure and dynamics of Titan's crust and its global evolution.
Kinetic Alfvén Waves From Magnetotail to the Ionosphere in Global Hybrid Simulation Associated With Fast Flows
Authors: Cheng Lei , Lin Yu , Perez J. D. , Johnson Jay R. , Wang Xueyi
Published: January 2020

We have used the Auburn Global Hybrid Code in 3‐D to study the generation, dynamics, and global structure of kinetic Alfvén waves (KAWs) from the magnetotail to the ionosphere. Our results show that KAWs are generated in magnetic reconnection in the plasma sheet, located around fast flows, and carrying transverse electromagnetic perturbations, parallel Poynting fluxes, parallel currents, and parallel electric field. Overall, shear Alfvénic turbulent spectrum is found in the plasma sheet. The KAWs are shear Alfvén waves possessing short perpendicular wavelength with
, where
is the perpendicular wave number and
the ion Larmor radius. The KAWs are identified by their dispersion relation and polarizations. The structures of these KAWs embedded in the plasma sheet are also revealed by placing a virtual satellite in the tail. In order to understand whether the Poynting fluxes carried by the shear Alfvén waves/KAWs in the plasma sheet can be carried directly along field lines to the ionosphere, we have tracked the wave propagation from the plasma sheet to the ionosphere. It is found that in front of the flow‐braking region, the structure and strength of the shear Alfvén waves are significantly altered due to interaction with the dipole‐like field, mainly by the flow shear associated with the azimuthal convection. Also in front of the dipole‐like field region, ion kinetic effects (Hall effects) lead to the generation of additional pairs of KAWs. As such, the generation and transport of the shear Alfvén waves/KAWs to the ionosphere are illustrated for the first time in a comprehensive manner on the global scale.
Estimation of Planar Trend Model Parameters for Midlatitude Ionosphere
Authors: Kumbay Yildiz S. , Arikan F.
Published: January 2020

Being under influence of the polar and equatorial regions, the midlatitude ionosphere poses an important challenge in structural modeling. In this study, the general understanding of regional planar trend model is investigated for 2011 by estimation of trend coefficients in the least squares sense. The northern midlatitude is divided into 24 nonoverlapping regions of 10° by 20° in latitude and longitude, respectively. The magnetic conjugates of 24 regions in the Southern Hemisphere are also extracted. The total electron content values are obtained from global ionospheric maps (GIM) with spatial resolution of 2.5° by 5° in latitude and longitude, respectively. The temporal resolution of GIM can be 1 or 2 hr. Estimated planar trend coefficients are used to reconstruct model maps. The difference between GIM and the estimated planar model is obtained in normalized
norm squares sense. It is observed that the planar trend model in latitude and longitude is an agreeable model for total electron content over midlatitude regions for both Northern and Southern Hemispheres. The estimated model parameters generally follow the diurnal, seasonal, and semiannual trend structures of midlatitude ionosphere. The deviations from the model occur mostly during severe disturbances such as geomagnetic storms. The difference between the reconstructed model maps with estimated parameters and GIM is generally under 1% for land and 2% to 5% for ocean regions. The only region that has a very high spread and mostly up to 10% difference with the GIM throughout the year is on the California Current.
ML‐Helio: An Emerging Community at the Intersection Between Heliophysics and Machine Learning
Authors: Camporeale Enrico ,   The Scientific Organizing Committee of ML‐Helio
Published: January 2020

The advancements and breakthroughs achieved in the last 5–10 years in Artificial Intelligence and machine learning (ML) have not gone unnoticed in the scientific community. The body of literature that borrows techniques from ML has steadily grown in all fields of physics. Space physics is particularly well posed to exploit ML due to the large amount of (often under scrutinized) data accumulated over the last few decades. Indeed, ML techniques can offer insights into the data that might enhance our understanding of physical mechanisms. Many of the pioneering studies on the use of ML in Space Physics have been led by several individuals who have independently taken the burden of moving out of their comfort zone to climb the steep slope of learning new jargon, new methodologies, and new coding skills. Such early adopters have recently convened in Amsterdam for the first conference on machine learning in heliophysics. The conference has laid the foundation for a new emerging community, and this commentary summarizes the discussions and steps taken to make such community flourish.
Square‐Root Variable Metric‐Based Nullspace Shuttle: A Characterization of the Nonuniqueness in Elastic Full‐Waveform Inversion
Authors: Liu Qiancheng , Peter Daniel
Published: January 2020

Full‐waveform inversion (FWI) is for most geophysical applications an ill‐posed inverse problem, with nonunique solutions. We examine its nonuniqueness by exploring the nullspace shuttle, which can efficiently generate an ensemble of data fitting solutions. We construct this shuttle based on a quasi‐Newton method, the square‐root variable‐metric (SRVM) method. The latter provides access to the inverse data‐misfit Hessian in FWI for large‐scale applications. Combining the SRVM method with a randomized singular value decomposition, we obtain the eigenvector subspaces of the inverse data‐misfit Hessian. Its primary eigenvalue and eigenvector are considered to determine the null space of inversion result. Using the SRVM‐based nullspace shuttle, we can modify the inverted result a posteriori in a highly efficient manner without corrupting the data misfit. Also, because the SRVM method is embedded through elastic FWI, our method can be extended to multiparameter problems. We confirm and highlight our approach with the elastic Marmousi example.
Dynamical Ocean Response Controlling the Eastward Movement of a Heat Content Anomaly Caused by the 18.6‐Year Modulation of Localized Tidally Induced Mixing
Authors: Osafune S. , Kouketsu S. , Masuda S. , Sugiura N.
Published: January 2020

Numerical experiments based on a long‐term ocean state estimate have been used in previous work to demonstrate that the 18.6‐year modulation of localized tidally induced vertical mixing can influence wintertime sea surface temperature (SST) over a broad area of the northern North Pacific, and may play a role in determining the spatial structure of the Pacific Decadal Oscillation (PDO). This study investigates the mechanism driving the model annual mean surface layer heat content anomaly (SHCa), which is correlated with the SST anomaly, at a location near the center of the PDO in the eastern Pacific. The modulation of mixing first induces an 18.6‐year oscillatory SHCa in the western boundary region, which moves eastward along the boundary between the subtropical and subarctic gyres, taking
10 years to reach the eastern region. Adjoint sensitivity analysis is applied to confirm the importance of the dynamical response of the ocean to the eastward motion of the SHCa. It is shown that the generation of a temperature anomaly by wave‐related current anomalies works to delay the eastward motion of the SHCa. Results also suggest that the generation of a spiciness anomaly in the open ocean may play a role. Although further studies are required to clarify whether the mixing modulation has an impact on the actual climate variability, the mechanism can be applied to any location along an eastward current, independent of the periodicity of the phenomena, and thus might have wide applicability in efforts to understand the role of the ocean in the climate system.
How Machine Learning and High‐Resolution Imagery Can Improve Melt Pond Retrieval From MODIS Over Current Spectral Unmixing Techniques
Authors: Wright Nicholas C. , Polashenski Chris M.
Published: January 2020

Meltwater that pools on the surface of Arctic sea ice enhances solar absorption and accelerates further ice melt. The impact of melt ponds on energy absorption is controlled primarily through their influence on ice albedo, which is, in turn, governed in large part by the ponds' spatial coverage. This work seeks to observe the spatial coverage of melt ponds across the Arctic basin with sufficient accuracy to investigate pond‐albedo feedback and presents an improved technique to achieve this goal. We approach the problem by using the Open Source Sea Ice Processing algorithm to classify surface features in submeter resolution optical satellite imagery over select sites where such imagery is available. These data establish “true” estimates of pond coverage and the ponds' spectral reflectance. This information is then used to inform, improve, and test spectral unmixing and machine learning techniques that seek to determine melt pond coverage from more widely available, but lower resolution, optical satellite imagery (e.g., Moderate Resolution Imaging Spectroradiometer). The new machine learning approach improves accuracy from prior work and can contribute to improved efforts to validate melt pond models or understand trends in pond coverage. Nevertheless, we encounter and carefully document significant challenges to retrieving melt pond fractions from low‐resolution optical imagery. These limit accuracy to levels below that necessary for resolving climatologically important trends. We conclude that greatly expanding the collection of high‐resolution satellite imagery over sea ice is necessary to monitor melt pond coverage with the accuracy needed by the scientific community.
The Forest Effects on the Isotopic Composition of Rainfall in the Northwestern Amazon Basin
Authors: Ampuero A. , Stríkis N. M. , Apaéstegui J. , Vuille M. , Novello V. F. , Espinoza J. C. , Cruz F. W. , Vonhof H. , Mayta V. C. , Martins V. T. S. , Cordeiro R. C. , Azevedo V. , Sifeddine A.
Published: January 2020

In the Amazon basin, intense precipitation recycling across the forest significantly modifies the isotopic composition of rainfall (δ18O, δD). In the tropical hydrologic cycle, such an effect can be identified through deuterium excess (dxs), yet it remains unclear what environmental factors control dxs, increasing the uncertainty of dxs‐based paleoclimate reconstructions. Here we present a 4‐year record of the isotopic composition of rainfall, monitored in the northwestern Amazon basin. We analyze the isotopic variations as a function of the air mass history, based on atmospheric back trajectory analyses, satellite observations of precipitation upstream, leaf area index, and simulated moisture recycling along the transport pathway. We show that the precipitation recycling in the forest exerts a significant control on the isotopic composition of precipitation in the northwestern Amazon basin, especially on dxs during the dry season (r = 0.71). Applying these observations to existing speleothem and pollen paleorecords, we conclude that winter precipitation increased after the mid‐Holocene, as the expansion of the forest allowed for more moisture recycling. Therefore, forest effects should be considered when interpreting paleorecords of past precipitation changes.