bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of Supermassive Black Hole Seeds in ETG Star-forming Progenitors: Multiple Merging of Stellar Compact Remnants via Gaseous Dynamical Friction and Gravitational-wave Emission
Authors: Boco L. , Lapi A. , Danese L.
Published: March 2020

We propose a new mechanism for the growth of supermassive black hole (BH) seeds in the star-forming progenitors of local early-type galaxies (ETGs) at z ≳ 1. This envisages the migration and merging of stellar compact remnants (neutron stars and stellar-mass BHs) via gaseous dynamical friction toward the central high-density regions of such galaxies. We show that, under reasonable assumptions and initial conditions, the process can build up central BH masses of the order of 104–106
M
⊙ within some 107 yr, so effectively providing heavy seeds before standard disk (Eddington-like) accretion takes over to become the dominant process for further BH growth. Remarkably, such a mechanism may provide an explanation, alternative to super-Eddington accretion rates, for the buildup of billion-solar-massed BHs in quasar hosts at z ≳ 7, when the age of the universe ≲0.8 Gyr constitutes a demanding constraint; moreover, in more common ETG progenitors at redshift z ∼ 2–6, it can concur with disk accretion to build such large BH masses even at moderate Eddington ratios ≲0.3 within the short star formation duration ≲Gyr of these systems. Finally, we investigate the perspectives to detect the merger events between the migrating stellar remnants and the accumulating central supermassive BH via gravitational-wave emission with future ground- and space-based detectors such as the Einstein Telescope and the Laser Interferometer Space Antenna.
Modeling the Early Evolution of a Slow Coronal Mass Ejection Imaged by the Parker Solar Probe
Authors: Rouillard Alexis P. , Poirier Nicolas , Lavarra Michael , Bourdelle Anthony , Dalmasse Kévin , Kouloumvakos Athanasios , Vourlidas Angelos , Kunkel Valbona , Hess Phillip , Howard Russ A. , Stenborg Guillermo , Raouafi Nour E.
Published: March 2020

During its first solar encounter, the Parker Solar Probe (PSP) acquired unprecedented up-close imaging of a small coronal mass ejection (CME) propagating in the forming slow solar wind. The CME originated as a cavity imaged in extreme ultraviolet that moved very slowly (<50 km s−1) to 3–5 solar radii (R
⊙), where it then accelerated to supersonic speeds. We present a new model of an erupting flux rope (FR) that computes the forces acting on its expansion with a computation of its internal magnetic field in three dimensions. The latter is accomplished by solving the Grad–Shafranov equation inside two-dimensional cross sections of the FR. We use this model to interpret the kinematic evolution and morphology of the CME imaged by PSP. We investigate the relative role of toroidal forces, momentum coupling, and buoyancy for different assumptions on the initial properties of the CME. The best agreement between the dynamic evolution of the observed and simulated FR is obtained by modeling the two-phase eruption process as the result of two episodes of poloidal flux injection. Each episode, possibly induced by magnetic reconnection, boosted the toroidal forces accelerating the FR out of the corona. We also find that the drag induced by the accelerating solar wind could account for about half of the acceleration experienced by the FR. We use the model to interpret the presence of a small dark cavity, clearly imaged by PSP deep inside the CME, as a low-density region dominated by its strong axial magnetic fields.
MHD Mode Composition in the Inner Heliosphere from the Parker Solar Probe’s First Perihelion
Authors: Chaston C. C. , Bonnell J. W. , Bale S. D. , Kasper J. C. , Pulupa M. , Wit T. Dudok de , Bowen T. A. , Larson D. E. , Whittlesey P. L. , Wygant J. R. , Salem C. S. , MacDowall R. J. , Livi R. L. , Vech D. , Case A. W. , Stevens M. L. , Korreck K. E. , Goetz K. , Harvey P. R. , Malaspina D. M.
Published: March 2020

Field and plasma variations during the first perihelion pass of the Parker Solar Probe (PSP) from 53 into 35 solar radii (R

S
) from the Sun and over a frequency range in the spacecraft frame (f
SC) from 0.0002 to 0.2 Hz are decomposed into constituent magnetohydrodynamic (MHD) modes. The analysis operates on measurements of the MHD variables recorded between impulsive, large amplitude rotations of the magnetic field to reveal the dominance of a broad spectrum of shear Alfvén waves propagating antiparallel (backward) to the background magnetic field (
B

0) with a significant fraction of spectral energy density in the backward slow mode and, to a lesser extent, fast mode waves. While all three MHD modes provide Poynting flux directed outward from the Sun the impulsive rotations of B
0 from inward to outward radial orientations provide intervals of outward and inward propagation in the plasma frame, respectively. This morphology is suggestive of outward wave propagation from a near Sun source along kinked field lines that provide alternating radial B
0 orientations as the magnetic field is advected with the flow over the spacecraft. Shear Alfvén and slow mode spectral energy density is generally largest within intervals of reversed radial B
0, while the fast mode tends to occur outside these regions, albeit with lower intensity. The spectral energy density in the forward propagating modes increases with f
SC above 0.01 Hz, which is suggestive of back scatter in the plasma frame of the dominant backward modes from the radial field reversals and associated inhomogeneities of the embedded plasmas.
Proton Temperature Anisotropy Variations in Inner Heliosphere Estimated with the First Parker Solar Probe Observations
Authors: Huang Jia , Kasper J. C. , Vech D. , Klein K. G. , Stevens M. , Martinović Mihailo M. , Alterman B. L. , Ďurovcová Tereza , Paulson Kristoff , Maruca Bennett A. , Qudsi Ramiz A. , Case A. W. , Korreck K. E. , Jian Lan K. , Velli Marco , Lavraud B. , Hegedus A. , Bert C. M. , Holmes J. , Bale Stuart D. , Larson Davin E. , Livi Roberto , Whittlesey P. , Pulupa Marc , MacDowall Robert J. , Malaspina David M. , Bonnell John W. , Harvey Peter , Goetz Keith , de Wit Thierry Dudok
Published: March 2020

We present a technique for deriving the temperature anisotropy of solar wind protons observed by the Parker Solar Probe (PSP) mission in the near-Sun solar wind. The radial proton temperature measured by the Solar Wind Electrons, Alphas, and Protons (SWEAP) Solar Probe Cup is compared with the orientation of local magnetic field measured by the FIELDS fluxgate magnetometer, and the proton temperatures parallel and perpendicular to the magnetic field are extracted. This procedure is applied to different data products, and the results are compared and optimum timescales for data selection and trends in the uncertainty in the method are identified. We find that the moment-based proton temperature anisotropy is more physically consistent with the expected limits of the mirror and firehose instabilities, possibly because the nonlinear fits do not capture a significant non-Maxwellian shape to the proton velocity distribution function near the Sun. The proton beam has a small effect on total proton temperature anisotropy owing to its much smaller density relative to the core compared to what was seen by previous spacecraft farther from the Sun. Several radial trends in the temperature components and the variation of the anisotropy with parallel plasma beta are presented. Our results suggest that we may see stronger anisotropic heating as PSP moves closer to the Sun, and that a careful treatment of the shape of the proton distribution may be needed to correctly describe the temperature.
KAZAKHSTAN AND ESTONIA: EVALUATION OF PREFERENCES IN INTERMARRIAGES
Authors: Kozlov Vladimir
Published: March 2020

This paper is devoted to the "ethnic" preferences in partners’ choice for the inter-ethnic marriages inEstoniaandKazakhstan(countries with the share of Russians more than 20% in the total population). As a measure for the preferences the author uses inter-ethnic distance and for the calculation national census data by nationality and marriage status are used.
TELEMEDICINE IN THE ARCTIC ZONE OF RUSSIA
Authors: Natenzon M.
Published: March 2020

Russiais simultaneously carrying out two breakthrough projects: transition to digital health and the development of the Arctic zone. An unrestricted solution to these problems is the integrated use of telemedicine system solutions, technologies, stationary and mobile equipment. The relevant decisions are adapted to the specific living conditions of diﬀerent groups of the population in the Arctic zone.
Reserves for Increasing the Participation of the Population in the Labour Force
Authors: Sindyashkina Evgenia N. , Mukhina Irina I.
Published: March 2020

In the conditions of long-continued reduction of the working-age population size in Russia, researchers and practitioners are in search for ways to compensate demographic losses. One of the ways is the increase the labour force participation rate for certain socio-demographic groups of the population. The article examines the reserves and opportunities for expanding the involvement of young people, older persons, women with underage children in the workforce.
Impact of the demographic dividend on economic growth
Authors: Kazbekova Zarina
Published: March 2020

In the context of the working-age population decline in the Russian Federation, the study of the influence of the dynamics of the share of the working -age population on economic growth is of particular interest. The main purpose of the article is to assess the contribution of the first demographic dividend to the GDP per capita growth rate in Russia betwеen 1997 and 2015. The main methods used by the author of this work are statistical analysis and econometric modeling based on Rosstat data. According to the results obtained in the course of this study, the first demographic dividend provided about 13% growth of real GDP per capita in the Russian Federation in 1997-2015. It has been proved that the age structure of the population is important.
Symptomatic Intratendinous Ganglion Cyst of the Patellar Tendon
Authors: Jose Jean , O’Donnell Kevin , Lesniak Bryson
Published: March 2020

Ganglion cysts have been previously described throughout the body, most commonly about the wrist, hand, knee, ankle, and feet. When symptomatic, they may interfere with joint mechanics, resulting in snapping, catching, and locking. Intratendinous ganglion cysts lack a synovial epithelial lining and are thought to develop from the mucoid degeneration of connective tissue caused by chronic irritation, chronic repetitive injury, and chronic ischemia. On magnetic resonance imaging, ganglion cysts originating from tendons, ligaments, tendon sheaths, menisci, or joint capsules appear as well-defined lobulated masses that follow simple or complex fluid signal intensity on all pulse sequences, with enhancing walls and internal septations on post-contrast images. There may be appreciable degeneration and partial tearing of the structure of origin, particularly if associated with tendons. On ultrasonography, they present as hypoechoic masses, with internal septations and lobulations of varying sizes, without significant vascularity on power or color Doppler sampling. A thin fluid neck extending from the structure of origin (tail sign), when present, is a reliable sign of a ganglion cyst.

This article describes a sonographically guided technique to treat symptomatic ganglion cysts within the patellar tendon. Complete evacuation of the ganglion cyst, with disappearance of the tail sign, is considered the determining factor for a successful procedure. A similar technique can be used for the treatment of other symptomatic intratendinous ganglion cysts elsewhere in the body. To our knowledge, symptomatic intratendinous ganglion cysts within the patellar tendon and their treatment have not been previously reported.
CHARLEY PATTON MED SAKRALNIM IN PROFANIM
CHARLEY PATTON BETWEEN SACRAL AND PROFANE

Authors: Weber Jane
Published: March 2020

Prispevek obravnava sakralne skladbe Charleyja Pattona, posnete med letoma 1929 in 1934 na gramofonskih ploščah z 78 o/min. Na njih so dokumentirane Pattonove številne glasbene značilnosti. Moč njegove glasbe je na primer pogosto najočitnejša v njegovih spiritualih in gospelih. Avtor preučuje ločnico med posvetno in sakralno glasbo v Pattonovi glasbeni zapuščini in širše v afroameriški kulturi, pri čemer se osredinja na prehajanja te ločnice in prepletanje glasbenih slogov ter ugotavlja, da se je Patton v glasbenih izvedbah zlahka sprehajal med sakralnim in posvetnim.***The article introduces Charley Patton’s religious songs on 78 rpm gramophone records recorded in the period from 1929 to 1934. Almost all of Patton’s varied musical skills come out on those records. For example, the power of his music is often most evident in his spiritual and gospel work. The author writes about the divide between secular and sacred music in Afro-American culture and particularly in Patton’s legacy. The author was also mainly interested in crossing of that dividing line and in blending of various styles, and he ascertained that in his performances Patton easily crossed the line of separation between sacred and profane.
Satellite television transmission in the world - broadcasting systems and standards
Authors: Jaksic Branimir , Miljkovic Dragisa , Maksimovic Vladimir , Petrovic Mile , Gvozdic Branko
Published: March 2020

This paper considers the characteristics of satellite television transmission in the world. An overview of the development of satellite television is given through the following characteristics: broadcasting systems - analog and digital (SDTV, HDTV, UHDTV), frequency band (C, Ku, Ka), broadcasting standards (DVB-S, DVB-S2, DigiCipher, DSS), as well as the availability of TV services Free-To-Air TV (FTA) and PAY TV. All of these characteristics were considered both at the global and at the regional level: North America, South America, Europe, Africa, Russia, Asia, and Australia. The gathered data are presented in tabular form and presented graphically for the period from 1996 to 2018. Based on the presented results, an analysis of the development of satellite television transmission was carried out in accordance with the characteristics of the broadcast.
Urban growth dynamics based on surface Albedo changes in Petrolina, Brazil
Authors: Oliveira Michele Laurentino de , Rufino Iana Alexandra Alves , Cunha John Elton de Brito Leite , Vasconcelos Rochele Sheila , Brito Higor Costa de
Published: March 2020

Cities keep growing, and in most of the cases this expansion process is hard to model and describe for planning actions. Quantitative methods are increasingly used to help planning, monitoring, and regulating urban land-use processes. Remote sensing images series are making possible different types of spatial-temporal analysis of the Earth surface. Surface albedo is a remote sensing product acquired in a long series of satellite images such as Landsat (more than 40 years of observation). Those analyses allow measuring waterproofed areas for urban drainage studies, as well as monitoring urban spreading patterns, growth vectors, and issues related to comfort and environmental quality, as well as about land use and land-use planning (directives for master plans) among others. This article shows the direct applicability of surface albedo changes as an indicator of urban land-cover changes. The current study analyzed the urban area of Petrolina County (PE) in the following periods: 2001 and 2006, 2006 and 2011, and 2011 and 2017. Such analysis uses the surface albedo variation along the time and results showed a strong correlation between increased surface albedo and urban expansion. Besides, it enabled to observe the relation between the high urban growth in the 2011-2017 period and the urban spot expansion by 14% (approximately 590 thousand square meters of territorial extension). The Urban development stood out in the Northern and Southwestern regions of Petrolina County.
Brazilian continental aquaculture: a model for the development of its regularization
Authors: Nogueira Sara Monaliza Sousa , Santos Marco Aurélio dos , Lordelo Sandro Alberto Vianna , Farias Filho José Rodrigues de
Published: March 2020

The Brazilian fish farming in Federal reservoirs is being discouraged by the country's current legal system due to the bureaucracy and the involvement of many agencies. This research provides a survey of the problems related to the current processes of Authorization of Aquaculture in Federal Waterbodies and Environmental Licensing of the activity and develops a model that gathers theories for improving these processes. In order to do this, 68 questionnaires were applied to key-agents of the sector from different regions of the country. Also, a Grounded Theory methodology was used to organize, code, and analyze the data collected and to outline the model of the main emerging theories. The model revealed 21 recommendations to unlock and accelerate the current process of regularization. Putting some of these actions into practice, it’s believed that fish farming would be able to attract new and old interested parties, reducing many illegal enterprises.
A simulated case study of a library in Brazil to improve energy efficiency
Authors: Gamarra Melanie Gissel Urdangarín , Siqueira Jair Antonio Cruz , Pereira Fabyo Luiz
Published: March 2020

The aim of this study is to quantify the energy savings of a library in the city of Foz do Iguaçu/Brazil, through simulations in EnergyPlus. Due to the great participation of air conditioning in the electric consumption of the building under study, the following proposals were studied: the exchange of the current split air conditioning units by a Variable Refrigerant Flow (VRF) system; the application of solar control films on the glasses; and both options together. The methodology followed these steps: firstly, it was simulated the current electricity consumption and the results were validated with real measures; secondly, the retrofitting measures were sized and implemented in the program and the energy savings were quantified; finally, an economic analysis was performed in order to determine the feasibility of the proposals. As a result, the VRF system showed an annual saving in air-conditioning of 42.08% related to the mini-split system. The annual electricity savings were 32.01, 2.14 and 32.80% for the VRF, solar control films, and both options together, respectively. The feasibility analysis of the VRF, considering financing and for a scenario consistent with the historical average growth of the electricity prices and inflation rate, showed that the use of a VRF instead of the splits units recovers the initial investment in 14 years. The application of solar control films proved to be economically unfeasible.
Prática da automedicação entre estudantes de enfermagem de instituição de ensino superior/ Self-medication practice among nursing students at a higher education institution
Authors: Bohomol Elena , Andrade Camilla Moreira
Published: March 2020

Objetivo: conhecer a prevalência, os medicamentos utilizados e os principais motivos da automedicação entre os discentes de um curso de enfermagem em uma instituição de ensino superior. Método: estudo transversal descritivo, de abordagem quantitativa, com amostra de 126 estudantes matriculados no curso de graduação em enfermagem de instituição pública. A coleta de dados foi realizada por meio de um questionário estruturado disponibilizado por aplicativo e foram analisados por estatística descritiva. Resultados: os estudantes tinham entre 18 e 25 anos de idade (85,7%), a maioria do sexo feminino (92,9%) e moravam com familiares (86,5%). Observou-se um alto índice de automedicação (99,2%), e a classe medicamentosa prevalente foi a dos analgésicos (28,7%) utilizados para alívio rápido da dor (88,1%) e levados à utilização pelo próprio conhecimento (73,8%). Conclusão: a alta prevalência de automedicação coloca em risco a saúde dos estudantes e reforça a necessidade de implementação de políticas públicas para a conscientização sobre o uso racional de medicamentos.
Polynomially weighted $\ell^p$-completions and group homology
Authors: Engel Alexander , Löh Clara
Published: March 2020

We introduce polynomially weighted

\ell^p

-norms on the bar complex of a finitely generated group. We prove that, for groups of polynomial or exponential growth, the homology of the completed complex does not depend on the value of

p

in the range

(1,\infty)

.
O círculo de bakhtin e suas possíveis contribuições aos debates teóricos no campo da Ciência da Informação
Authors: Castro Gilberto de , Nascimento Bruna Silva do
Published: March 2020

Objetivo: Este ensaio apresenta os argumentos principais utilizados por Araújo (2016) no seu artigo Novo quadro conceitual para a ciência da informação: informação, mediações e cultura no sentido de ampliar o escopo teórico da Ciência da Informação. Método: Utiliza abordagem qualitativa objetivando identificar possíveis contribuições do Círculo de Bakhtin à Ciência da Informação. Resultado: Na visão do autor, é preciso resgatar a Ciência da Informação de um certo abstracionismo conceitual, transformando-a numa ciência mais pragmática, em que questões subjetivas e sociais estejam presentes à reflexão sobre a informação. Para Araújo, esse novo viés estaria na direção do que vem sendo chamado na área de o terceiro modelo. Corroborando as expectativas do autor, o intuito deste trabalho é trazer algumas contribuições dos autores do Círculo de Bakhtin, que tendo a linguagem como o centro epistemológico do seu pensamento, enfrentaram pragmaticamente questões relativas à interação humana e à formação subjetiva. Conclusões: No conjunto das reflexões dos autores russos, encontra-se uma visão muito particular de semiótica e ideologia, a discussão sobre os gêneros de discurso, sua diversidade social de enunciados e os seus ambientes sociais de realização, e também contribuições significativas sobre a interpretação da constituição social de nossa subjetividade que podem contribuir para uma visão mais concreta e material da informação.
Occupational Therapy Practice Guidelines for Older Adults With Low Vision
Authors: Kaldenberg Jennifer , Smallfield Stacy
Published: March 2020

Importance: The aging of the population is generating increased demand for occupational therapy practitioners to address the occupational performance of those experiencing low vision.

Objective: This Practice Guideline, which is informed by systematic reviews on interventions for older adults with low vision, is meant to serve as a reference for occupational therapy practitioners to guide best practice in service delivery, improve quality of care, enhance consumer satisfaction, and justify occupational therapy services to external stakeholders. Interventions included in this guideline address performance of activities of daily living (ADLs) and instrumental activities of daily living (IADLs), reading, and leisure and social participation.

Method: We examined, synthesized, and integrated the results of three systematic reviews into recommendations for practice, education, and research.

Results: Thirty-eight articles were included in the systematic reviews, which served as the basis for clinical recommendations. A case study describes translation and application of the recommendations to clinical practice.

Conclusions and Recommendations: Strong evidence supports the role of occupational therapy for older adults with low vision. On the basis of the evidence, we recommend routine use of low vision rehabilitation for ADL and IADL impairments, multicomponent interventions to improve ADL and IADL performance and leisure and social participation, stand-based electronic magnification to enhance reading, and visual skills training to enhance reading for clients with a central field impairment. We recommend using client-centered problem-solving training to enhance ADL and IADL performance, reading, and leisure and social participation. Mainstream technology may be considered for use on a case-by-case basis to enhance reading performance. Finally, adapted tango may be considered for use on a case-by-case basis to enhance ADL and IADL performance and leisure and social participation.

What This Article Adds: This Practice Guideline provides a summary of the current evidence supporting occupational therapy intervention for older adults with low vision. It summarizes the emerging literature supporting the use of mainstream technology and provides additional support for the use of multicomponent intervention strategies.
Geocenter coordinates and Earth rotation parameters from GPS-only, GLONASS-only, Galileo-only, and the combined GPS+GLONASS+Galileo solutions
Authors: Sośnica Krzysztof , Zajdel Radosław , Bury Grzegorz , Strugarek Dariusz , Kaźmierski Kamil
Published: March 2020

The European GNSS – Galileo can be considered as fully serviceable with 24 active satellites in space since late 2018. Galileo satellites have a different revolution period than that of GPS and GLONASS, and moreover, two additional Galileo satellites are orbiting in an eccentric orbit which helps to decorrelate some global geodetic parameters.

This contribution shows the results from Galileo-only, GPS-only, GLONASS-only, and the combined multi-GNSS solutions with a focus on Earth rotation parameters and geocenter coordinates based on the 3-year solution. We discuss the system-specific issues in individual GNSS-derived series and resonances between satellite revolution periods and Earth rotation. We found that the Galileo-based and GLONASS-based parameters are inherently influenced by the spurious signals at the frequencies which arise from the combination of the satellite revolution period and the Earth’s rotation, e.g. 3.4 days for Galileo and 3.9 days for GLONASS. On the other hand, we observe a systematic drift of GPS-based UT1-UTC values with a magnitude of 8.1 ms/year which is due to the revolution period of the GPS satellites which is equal to half of the sidereal day and causes a deep resonance. For Galileo, the UT1-UTC drift is sixteen times smaller than that of GPS and equals just 0.5 ms/year. GLONASS-derived pole coordinates and geocenter coordinates show large spurious offsets with respect GPS and Galileo solutions, as well as with respect to the IERS-C04-14 series and Satellite Laser Ranging data. GLONASS-specific problems can be partially reduced by applying a box-wing orbit model and by reducing the number of estimated empirical orbit parameters. The quality of Galileo-derived geocenter coordinates is comparable to the GPS-based results. The Galileo-derived polar motion is affected by systematic errors in receiver and satellite antenna offsets. The best results of geocenter coordinates and Earth rotation parameters can be obtained from the combined GPS+Galileo+GLONASS solutions, however, some system-specific issues still remain in the combination.

 
Cenozoic sea-level and cryospheric evolution from deep-sea geochemical and continental margin records
Authors: Miller Kenneth , Browning James , Schmelz W. John , Kopp Robert , Mountain Gregory , Wright James
Published: March 2020

Cenozoic (past ~66 Myr) sea-level history reflects temperature changes and cryospheric evolution of the Earth from essentially ice-free conditions in the Early Eocene to bipolar ice sheets in the Quaternary. We derived a global mean sea level (GMSL) estimate for the Cenozoic using a new astronomically calibrated Pacific benthic foraminiferal δ18O splice from published records and a 2 Myr-smoothed Pacific bottom water temperature record based on published benthic foraminiferal Mg/Ca data. Our GMSL estimates are similar to sea-level estimates derived from “backstripping” (progressively accounting for compaction, loading and thermal subsidence) of cores from the mid-Atlantic U.S. continental margin. Peak global warmth, elevated GMSL, high CO2, and largely ice-free conditions occurred during the Early Eocene “Hothouse.” During the Middle-Late Eocene “Cool Greenhouse,” small ice sheets associated with lower atmospheric CO2 drove sea-level changes. Continental-scale ice sheets began in the Oligocene “Icehouse” (ca. 34 Ma), a permanent East Antarctic ice sheet began in the middle Middle Miocene (ca. 12.8 Ma), and full, bipolar glaciation began in the Quaternary (ca. 2.55 Ma). The Last Glacial Maximum (20-27 ka) was the largest lowering of GMSL (~130 m) of the Mesozoic-Cenozoic and GMSL rise during last deglaciation (ca. 19-10 ka) exceeded 40-45 mm/yr.  Sea-level rise progressively slowed from 10 ka to 2 ka and was then at stillstand until late 19th to early 20th century when rates began to rise. Despite large uncertainties in proxies, our study reaffirms that throughout the Cenozoic, high long-term (107-year scale) CO2 was associated with warm climates and high sea levels.  However, sea level-change was dominated by periodic, astronomically controlled (10’s kyr-Myr scale) Milankovitch variations superimposed upon longer-term changes driven by CO2.
Reconstructing the propagation of Whistlers observed in ELF during ASM burst sessions from the lightning strikes to their detection and validation of IRI model
Authors: Coïsson Pierdavide , Truhlik Vladimir , Mlynarczyk Janusz , Hulot Gauthier , Madelon Rémi , Bonnot Olivier , Vigneron Pierre , Burešová Dalia , Chum Jaroslav , Rzonca Pawel , Kulak Andzej
Published: March 2020

New sessions of burst-mode acquisition of the Absolute Scalar Magnetometers (ASM) onboard Swarm satellites have been conducted during 2019 , with the aim of acquiring events covering various geophysical conditions, in terms of geomagnetic latitude, spacecraft Local Time and season, to better understand the conditions under which the ELF component of whistlers is excited and can be detected at satellite altitude and to provide an additional ionospheric monitoring.

Among all candidate events detected using an automatic algorithm specifically designed for that purpose, a selection of remarkable whistler events have been further studied. Firstly, from the estimation of the whistler dispersions, the origin times of the lightning discharge have been estimated and validated with ground data from the World ELF Radiolocation Array (WERA), providing the locations of the lightning strikes and their intensity in the ELF spectral band. These locations have also been validated using data from the World Wide Lightning Location Network (WWLLN) providing measurements.

Subsequently, to reconstruct the propagation path inside the ionosphere of the ELF component of the whistler, a dedicated ray-tracing algorithm has been designed. It uses a background ionosphere model of electron and ions based on the International Reference Ionosphere. For the purposes of producing a ionospheric representation as close as possible to the experimental conditions, the update of the main ionospheric parameters based on worldwide ionosonde data IRTAM has been applied, validating it by using ionosonde data available in the vicinity of specific whistler events. The in-situ electron density measurements of the Electric Field Instrument (EFI) of Swarm satellite have also been used to constrain the model in the topside ionosphere.

We present the recent results obtained during some of these burst sessions, and discuss the possibility offered by this new dataset to validate global ionospheric models and provide a new avenue in ionospheric research, that could be also pursued by the NanoMagSat mission.
A data-mining approach to investigate El Niño damage in Peru
Authors: Brill Fabio , Kreibich Heidi
Published: March 2020

Compound natural hazards, like El Niño events, which trigger torrential rain, mudslides, riverine and flash floods, cause high damage to society. An improved risk management based on reliable risk assessments are urgently needed. However, knowledge about the complex processes leading to El Niño damage is lacking, and so are loss models.  We explore a large dataset of building damage from the coastal El Niño event 2017 in Peru. We use data-mining techniques to analyse data of damage grades of about 180.000 affected houses together with satellite observations and open geo-information. In a first step, we use unsupervised clustering (t-SNE + OPTICS) to separate regions of different dominant processes. Secondly, we train various supervised classification algorithms and create feature importance rankings per cluster, to identify drivers of observed damage for each of these regions. A comparison of different algorithms provides further insights about the potential and limitations of these methods and datasets. Results indicate that topographic wetness is the most important indicator, as selected by the algorithms, when using the entire dataset. Rainfall sum and maximum from TRMM satellite measurements are identified as damage driver despite the coarse spatial resolution. Also urbanity, based on a focal window around the global urban footprint, appears to play a role for the amount of damage. At least a coarse separation of processes is possible: the slope length and steepness, bare soil index, stream power index, and maximum rainfall are dominating the damage processes in lower mountain ranges and canyons, indicating rapid processes. Damage in upper mountain areas seem more influenced by the rainfall sum, local topographic position, and vegetation cover. In the lowlands, topographic wetness is very dominant, indicating ponding water or riverine floods. As opposed to previous work, this study constructs importance rankings based entirely on real observed damage to buildings. It is therefore a step towards data-driven damage assessments for El Niño events.
The “syn” and “post” depositional evolution of a foredeep basin segmented by orogen-transversal tectonic structures: the case of the Cervarola Sandstones Formation, Miocene, Northern Apennines, Italy
Authors: Piazza Alberto , Tinterri Roberto , Artoni Andrea
Published: March 2020

In collisional belts, foredeep turbidites are tracers of the evolution of the orogenic wedge. Syn-depositional tectonics affects the sedimentary facies distribution of the turbidite deposits, while post-depositional tectonics generates the major structures that deform the foredeep basins. The Aquitanian to Burdigalian Cervarola turbiditic succession is one of the main Oligo-Miocene foredeep units that characterize the northwestern portion of the Northern Apennines. The reconstructed sin and post depositional evolution of the Cervarola succession reveals that orogen-transversal tectonic structures strongly and persistently controlled this turbiditic succession, from the time turbidites were infilling the foredeep basin (Aquitanian-Burdigalian) to the time this foredeep deposits became a major and complex thrust sheet of the Northern Apennines orogenic wedge (post-Burdigalian-Present). The syn-depositional history of the Cervarola turbiditic succession has been defined through a detailed facies analysis that has allowed the basin morphology to be accurately constrained. Then, the post-depositional history has been addressed to define the multi-scale deformations preserved in the Cervarola succession through the following approaches: 1) analysis of published geological maps, 2) detailed field mapping, 3) construction of geological cross sections across the major folds, 4) analysis of meso-scale structures and 5) analysis of a seismic reflection profile. The study has outlined that the foredeep basin morphology was tectonically controlled and segmented by compressive structures transversal to the NW-SE basin elongation. The same structures were also present during the post-depositional compressive phases that built up the orogenic wedge and they have been even reactivated in the latest extensional events that have dismembered the mountain range. These orogeny-transversal and long-lasting (~23Myrs) lineaments cross-cut the entire tectonic stacking of the Northern Apennines, affecting tectonic units which suffered different amount of translation during the mountain building, making the reconstruction of the geological evolution possible only with an integrated approach as performed in this work.
Structure and evolution of the Jan Mayen Microcontinent
Authors: Dannowski Anke , Schnabel Michael , Barckhausen Udo , Franke Dieter , Thorwart Martin , Funck Thomas , Engels Martin , Berndt Christian
Published: March 2020

The Jan Mayen Ridge (JMR) is a 150-km-long and 10–30 km wide seafloor expression in N-S direction in the centre of the North Atlantic and part of the Jan Mayen Microcontinent (JMMC). Previous studies show that the eastern flank of the JMR was formed during the breakup of the Norway Basin along today’s Aegir Ridge, prior to magnetic anomaly C23 (~50 Ma). The western margin of the JMMC is conjugate to East Greenland. Rifting gradually propagated northward, likely from Chron C21 (~46 Ma) onward. Fan-shaped magnetic anomalies in the Norway Basin suggest that the JMMC must have rotated counter-clockwise. The JMR is likely underlain by continental crust. Volcanic flows have been observed within the sediments in the Jan Mayen Basin (JMB). While a relatively uniform upper crust was observed throughout the JMMC, the thickness of the lower continental crust varies significantly from up to 15 km below the JMR down to almost zero thickness towards the western part of the JMB. However, the character of the lower crust and the development of the conjugate East Greenland – JMMC margins during Oligocene are still disputed.

Here, we investigate the crustal structure of the JMMC using a new 265-km-long seismic refraction line crossing the JMMC at 69.7°N in E-W direction, which was acquired on board of RV Maria S. Merian during cruise MSM67. The profile consists of 30 ocean bottom seismometers (OBS) with a spacing of 9.5 km. The dataset was complemented by on-board gravity measurements and a magnetometer array towed behind the vessel during shooting. The line extends from oceanic crust in the Norway Basin, across the microcontinent and into oceanic crust that formed at the presently active mid-oceanic Kolbeinsey Ridge. The magnetic profile shows old seafloor spreading anomalies in the east (likely anomaly 24, ~52 Ma), then low amplitude magnetic anomalies in the central portion of the profile, which are typical for many plutonic continental rocks. On the western part of the profile, high amplitude anomalies of younger oceanic crust (likely anomalies C5C trough C6, ~19–16 Ma) are recognized near the western termination of the JMB. The seismic velocity distribution and crustal thickness vary strongly along the profile, with velocities typical for oceanic crust at either end of the profile and a thickened crust (12–13 km) underneath the JMR. This suggests that the JMMC consists of thinned continental crust with a total width of 100 km.
Bank erosion processes within the fluvial corridor of the St. Lawrence River: causes, drivers and future challenges.
Authors: Chassiot Léo , Bernier Jean-François , Lajeunesse Patrick
Published: March 2020

The St. Lawrence River is one of the largest river affected by seasonal ice formation outside the periglacial domain. It is also a major socio-economical axis in eastern North America where human activities and facilities are numerous within its fluvial corridor, upstream Quebec City (QC, Canada). Recent flooding episodes in 2017 and 2019 have shown that the sustainability of the St. Lawrence River and thus its socio-economic and ecological services will likely be altered in a near future. Bank erosion today represents a major hazard for land owners, infrastructures and riverine ecosystems. Consequently, there is a growing need to integrate bank erosion hazard in order to ensure sustainable management of riparian areas and to adapt land-use planning strategies.

Literature review and field surveys allowed us to conceptualize a scientific framework about bank erosion dynamics in large rivers characterized by the formation of river ice. We used this framework within the fluvial corridor of the St. Lawrence River to identify bank erosion processes and their drivers, with a focus on the role of river ice and the impacts of anthropogenic stressors such as urbanization, riverbank concreting, large-scale damming, and maritime traffic. We illustrate erosion processes and their impacts through several case studies representing different ecosystems from the fluvial section of the St. Lawrence River. We then discuss the future changes in the nature, the timing, the frequency and the magnitude of bank erosion processes to address the challenges caused by climate change and increased human activities in the St. Lawrence, and more generally in large rivers affected by seasonal ice formation.
Imaging azimuthal anisotropy in the alpine crust using noise cross-correlations
Authors: Soergel Dorian , Pedersen Helle , Paul Anne , Stehly Laurent
Published: March 2020

Imaging azimuthal anisotropy from seismic noise cross-correlations is challenging, especially in very complex tectonic settings such as the Alps. In this region, the focus has been mainly on retrieving anisotropy using SKS-splitting data, but this data does not provide strong depth constraints. In this work, we map the azimuthal anisotropy of Rayleigh-wave velocity in the Alps using seismic noise cross-correlations. This initial study focusses on waves at ~15 s period. The study area is divided into small zones for which all the stations outside are used as virtual sources and all the stations inside are used as receivers. For each virtual source and each zone, we perform time domain beam forming to retrieve the local phase velocity and propagation direction. As the distances between sources and receivers are relatively small, we use an algorithm that takes into account circular wavefronts. The beam forming shows that the waveforms are very coherent for different stations within each small array, and that deviations from great-circle propagation can be significant. The resulting phase velocities in each zone show a variation with azimuth which is in some locations very small (indicating that anisotropy is insignificant) and which in all other locations has a 2θ dependency on azimuth, indicative of well resolved azimuthal anisotropy. Bootstrapping uncertainty estimates show that the results are very stable if a sufficient number of source stations is used. The combination of permanent stations with the temporary AlpArray stations provides us with a very high station density that allows us to carry out this measurement across a large area. The resulting anisotropy maps show a good resolution, with higher uncertainties in the Po plain and the areas of low station density. The clear 2θ azimuth dependency is a sign that our method overcomes both effects related to source directivity (which has an approximate 1θ dependency) and measurement instability which can be significant for Eikonal tomography in the case of irregular networks.
Changes of decadal SST Variations in the subpolar North Atlantic under strong CO2 forcing as an indicator for the ocean circulation’s contribution to Atlantic Multidecadal Variability
Authors: Hand Ralf , Bader Jürgen , Matei Daniela , Ghosch Rohit , Jungclaus Johann
Published: March 2020

The question, whether ocean dynamics are relevant for basin-scale North Atlantic decadal temperature variability is subject of ongoing discussions. Here, we analyze a set of simulations with a single climate model, consisting of a 2000-year pre-industrial control experiment, a 100-member historical ensemble, and a 100-member ensemble forced with an incremental CO2 increase by 1%/year. Compared to previous approaches, our setup offers the following advantages: First, the large ensemble size allows to robustly separate internally and externally forced variability and to robustly detect statistical links between different quantities. Second, the availability of different scenarios allows to investigate the role of the background state for drivers of the
variability. We find strong evidence that ocean dynamics, particularly ocean heat transport variations, form an important contribution to generate the Atlantic Multidecadal Variability (AMV) in the Max Planck Institute Earth System Model (MPI- ESM). Particularly the Northwest North Atlantic is substantially affected by ocean circulation for the historical and pre-industrial simulations. Anomalies of the Labrador Sea deep ocean density precede a change of the Atlantic Meridional Overturning Circulation (AMOC) and heat advection to the region south of Greenland.
Under strong CO2 forcing the AMV-SST regression pattern shows crucial changes: SST variability in the north western part of the North Atlantic is strongly reduced, so that the AMV pattern in this scenario is dominated by the low-latitude branch. We found a connection to changes in the deep water formation, that cause a strong reduction of the mean AMOC and its variability. Consequently, ocean heat transport convergence becomes less important for the SST variability south of Greenland.
Cumulative impact of small reservoirs : a review of estimations and methods
Authors: Habets Florence , Molénat Jérôme , Carluer Nadia , Douez Olivier , Leenhardt Delphine
Published: March 2020

Due to a reduce cost, availability of many favorable locations, easy access due to proximity, the number of small reservoirs has increased, especially in arid and semi-arid regions. The cumulative impact of reservoirs in a catchment is considered as the modifications induced by the reservoir network taken as a whole. The impact may exert on the flow regimes and sediment, nutrient and contaminant transfer, and thereby modify the ecological behaviour of the aquatic environment, the continuity of rivers and the habitats of organisms living in them. The cumulative impact is not necessarily the sum of individual and local modifications, because reservoirs may be inter-dependent. This is the case for instance in cascading reservoirs along a stream course. The cumulative impact is not straightforward to estimate, even solely considering hydrological impact, in part due to the difficulty to collect data on the functioning of those reservoirs. However, there are evidences that the cumulative impacts are not negligible.

This work is dedicated to a review of the studies dealing with the cumulative impact of small reservoirs on hydrology, focusing on the methodology as well as on the way the impacts are reported. It is shown that similar densities of small reservoirs can lead to different impacts on the quantitative water resource in different regions. This is probably due to the hydro-climatic conditions, and makes it difficult to define simple indicators to provide a first guess of the cumulative impact. The impacts vary also on time, with a more intense reduction of the river discharge during the dry years than during the wet years. This is certainly an important point to take into account in a context of climate change.

Habets, F., Molénat, J., Carluer, N., Douez, O. and Leenhardt,D, 2018, The cumulative impacts of small reservoirs on hydrology: A review, Science of The Total Environment, 643, 850-867, doi.org/10.1016/j.scitotenv.2018.06.188