bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cycle-dependent and cycle-independent surface tracers of solar magnetic activity
Authors: Sokoloff D. D. , V. N.  , Obridko  , I. M.  , Livshits  , Shibalova A. S. 
Published: March 2020

AbstractWe consider several tracers of magnetic activity that separate cycle-dependent contributions to the background solar magnetic field from those that are independent of the cycle. The main message is that background fields include two relative separate populations. The background fields with a strength up to 100 Mx cm−2 are very poorly correlated with the sunspot numbers and vary little with the phase of the cycle. In contrast, stronger magnetic fields demonstrate pronounced cyclic behaviour. Small-scale solar magnetic fields demonstrate features of fractal intermittent behaviour, which requires quantification. We investigate how the observational estimate of the solar magnetic flux density B depends on resolution D in order to obtain the scaling In BD = −k In D + a in a reasonably wide range. The quantity k demonstrates cyclic variations typical of a solar activity cycle. k depends on the magnetic flux density, i.e. the ratio of the magnetic flux to the area over which the flux is calculated, at a given instant. The quantity a demonstrates some cyclic variation, but it is much weaker than in the case of k. The scaling is typical of fractal structures. The results obtained trace small-scale action in the solar convective zone and its coexistence with the conventional large-scale solar dynamo based on differential rotation and mirror-asymmetric convection. Here we discuss the message for solar dynamo studies hidden in the above results.
Nano dust in space and astrophysics
Authors: Mann Ingrid , Li Aigen , Tanaka Kyoko K. 
Published: March 2020

AbstractThe theme of this focus meeting is related to the detection, characterization and modeling of nano particles — cosmic dust of sizes of roughly 1 to 100 nm — in space environments like the interstellar medium, planetary debris disks, the heliosphere, the vicinity of the Sun and planetary atmospheres, and the space near Earth. Discussions focus on nano dust that forms from condensations and collisions and from planetary objects, as well as its interactions with space plasmas like the solar and stellar winds, atmospheres and magnetospheres. A particular goal is to bring together space scientists, astronomers, astrophysicists, and laboratory experimentalists and combine their knowledge to reach cross fertilization of different disciplines.
Standardization in the UV with Astrosat and its issues related to star cluster studies
Authors: Shah Priya 
Published: March 2020

AbstractThe Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in Astrosat, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300-1800 Å), and the other for the near-ultraviolet (NUV) channel (2000-3000 Å) and the visible (VIS) channel (3200-5500 Å). We shall discuss the issues with standardization in the UV with reference to Astrosat Observations (Cycle A04). I shall discuss the problems faced in data-analysis and how these in turn lead to serious issues dealing with the color-magnitude diagarms, membership and age of the young embedded clusters studied.
FM14 Session 1: Bridging the Astronomy Research and Outreach Communities - Recent Highlights, Emerging Collaborations, Best Practices and Support Structures
Authors: Cheung Sze-leung , Vauclair Sylvie D. , Cui Chenzhou , Li Shanshan , Hanaoka Yoichiro , Hunt Sharon E. , Kawagoe Shio K. , Kusakabe Nobuhiko , Nakamura Shigeru , Maravelias Grigoris , Vourliotis Emmanouel , Marouda Krinio , Belias Ioannis , Kardasis Emmanouel , Papadeas Pierros , Strikis Iakovos D. , Vakalopoulos Eleftherios , Voutyras Orfefs , Marchetti Lucia , Jarrett Thomas H. , Marchis Franck , Malvache Arnaud , Marfisi Laurent , Borot Antonin , Arbouch Emmanuel , Villicaña-Pedraza I. , Carreto-Parra F. , Prugh S. , Lopez K. , Nuss J. , Cadena D. , Lopez V. , Shah Priya 
Published: March 2020

AbstractSection 1 of the FM14 focus on bridging the astronomy research and outreach communities - recent highlights, emerging collaborations, best practices and support structures. This paper also contains supplementary materials that point to contributed talks and poster presentations that can be found online.
The IAU Strategic Plan for 2020-2030: OAO
Authors: van Dishoeck Ewine F. , Meloy Elmegreen Debra 
Published: March 2020

AbstractThe IAU Strategic Plan for 2020-2030 presents an overview of all of the activities of the IAU along with priorities, key goals, mandates, and specific actions. Here future plans and goals are outlined for the Office of Astronomy for Development (OAO).
Evaluation of NCEP‐FNL and ERA‐Interim Data Sets in Detecting Tibetan Plateau Vortices in May–August of 2000–2015
Authors: Li Lun , Zhang Renhe , Wu Peili 
Published: March 2020

AbstractTibetan Plateau vortices (TPVs) are important rainfall triggers in southwestern and eastern China after they move off the plateau. Characteristics of the moving‐off TPVs derived from two gridded data sets, the final operational global analysis data from the Global Forecasting System of National Centers for Environment Prediction (NCEP‐FNL) and the ERA‐interim data from the European Centre for Medium‐Range Weather Forecasts, are evaluated against the Yearbooks of Tibetan Plateau Vortex and Shear Line (YB). Generally, NCEP‐FNL captures more moving‐off TPVs in YB than ERA‐interim does. Both gridded data sets perform the best in capturing the TPVs in YB in May and the worst in July. Zonal propagation distances of TPVs are apparently better revealed in NCEP‐FNL than in ERA‐interim, and the performances of NCEP‐FNL and ERA‐interim in showing the meridional propagation distances and lifespans are similar. Positional deviations of TPVs in NCEP‐FNL and ERA‐interim reveal that both data sets show good skills in presenting the TPVs locations, and NCEP‐FNL generally performs better than ERA‐interim. In both gridded data sets, positional deviations of TPVs are larger before the TPVs move off the plateau than after moving off, and zonal deviations are always larger than meridional deviations. Before the TPVs move off, NCEP‐FNL shows no specific preference for the directions of positional deviations, whereas ERA‐interim tends to present further west TPVs locations relative to those in YB. After the TPVs move off, TPVs in both gridded data sets are always observed to the west and north of the TPVs in YB, which is more significant in ERA‐interim.
Plutonic‐Squishy Lid: A New Global Tectonic Regime Generated by Intrusive Magmatism on Earth‐Like Planets
Authors: Lourenço Diogo L. , Rozel Antoine B. , Ballmer Maxim D. , Tackley Paul J. 
Published: March 2020

AbstractThe thermal and chemical evolution of rocky planets is controlled by their surface tectonics and magmatic processes. On Earth, magmatism is dominated by plutonism/intrusion versus volcanism/extrusion. However, the role of plutonism on planetary tectonics and long‐term evolution of rocky planets has not been systematically studied. We use numerical simulations to systematically investigate the effect of plutonism combined with eruptive volcanism. At low‐to‐intermediate intrusion efficiencies, results reproduce the three common tectonic/convective regimes as are usually obtained in simulations using a viscoplastic rheology: stagnant‐lid (a one‐plate planet), episodic (where the lithosphere is usually stagnant and sometimes overturns into the mantle), and mobile‐lid (similar to plate tectonics). At high intrusion efficiencies, we observe a new additional regime called “plutonic‐squishy lid.” This regime is characterized by a set of small, strong plates separated by warm and weak regions generated by plutonism. Eclogitic drippings and lithospheric delaminations often occur close to these weak regions, which leads to significant surface velocities toward the focus of delamination, even if subduction is not active. The location of the plate boundaries is strongly time dependent and mainly occurs in regions of magma intrusion, leading to small, ephemeral plates. The plutonic‐squishy‐lid regime is also distinctive from other regimes because it generates a thin lithosphere, which results in high conductive heat fluxes and lower internal mantle temperatures when compared to a stagnant lid. This regime has the potential to be applicable to the Early Archean Earth and present‐day Venus, as it combines elements of both protoplate tectonic and vertical tectonic models.
Finite‐Frequency Sensitivity Kernels for Seismic Noise Interferometry Based on Differential Time Measurements
Authors: Liu Xin 
Published: March 2020

AbstractFull waveform adjoint tomography has achieved great success in applications from global Earth structure using earthquakes to exploration seismology using active sources. When combined with ambient seismic noise data, however, the ambient noise cross correlations are subject to strong variability and bias due to nonstationary and unevenly distributed noise sources. As a result, the shape of the structure sensitivity kernel can deviate significantly from the classic banana‐doughnut kernel of a point source, which has been used in previous studies as an inference from empirical Green's function and contains bias. In this study I calculate the sensitivity kernel for ambient noise cross correlation by introducing an additional station to the classic two‐station setting. I compute sensitivity kernels for differential traveltime measurements. These differential sensitivity kernels show promise for canceling the overlapping part of the original source and structure kernels for pairs of stations in interferometry, thus significantly reducing the effect of nonisotropically distributed and nonstationary noise sources. I apply the ambient noise differential sensitivity kernel to synthetic data examples based on 2‐D membrane waves, though the approach will apply for 3‐D as well. Our results for multiple station pairs show promise for velocity tomography based on seismic noise interferometry when perfect information on noise source distribution is not available.
The Lithospheric Thickness Control on the Compositional Variation of Continental Intraplate Basalts: A Demonstration Using the Cenozoic Basalts and Clinopyroxene Megacrysts From Eastern China
Authors: Sun Pu , Niu Yaoling , Guo Pengyuan , Duan Meng , Wang Xiaohong , Gong Hongmei , Xiao Yuanyuan 
Published: March 2020

AbstractStudies on intraplate ocean island basalts have demonstrated the control of lithosphere thickness on the extent of melting and pressure of melt extraction (i.e., the lid effect). However, whether lithosphere thickness also controls the composition of within‐continent basalts remains unclear. Here, we test this hypothesis by studying the Cenozoic basalts contaitning clinopyroxene megacrysts from 10 localities throughout eastern continental China with a north‐south spatial coverage in excess of 2,500 km. Indeed, the geochemical parameters (e.g., abundances and ratios of major and trace elements) correlate well with the depth of the lithosphere‐asthenosphere boundary (LAB) calculated using the clinopyroxene barometry, showing significant lithospheric thickness control on basalt compositions. These observations offer further evidence for melt pooling (a melt rich layer) close beneath the LAB as a “stable magma reservoir” for crystallizing compositionally uniform clinopyroxene megacrysts to be carried by subsequent pulses of melt transport and eruption.
Biophysical Interactions in Driving the Summer Monsoon Chlorophyll Bloom Off the Somalia Coast
Authors: Lakshmi R. S. , Chatterjee Abhisek , Prakash Satya , Mathew Teesha 
Published: March 2020

AbstractThe biophysical interactions along the Somali coast are discussed during summer monsoon based on a numerical model study. The Somali coast is known to be the fifth largest upwelling region of the world ocean and one of the most productive regions of the globe. Based on scattered observations, mostly dated back to 1960s, it is widely accepted that the strong chlorophyll bloom along the Somali coast during summer is driven by upwelled nutrient flux. We show that the upwelling‐driven productivity is primarily limited to the northern part of the coast when examined along the shelf break off the Somalia coast. In contrast, productivity in the south of 9°N is driven by weaker upwelling in the early half of the summer monsoon but later dominated by the wind‐based mixing induced entrainment and therefore shows much weaker chlorophyll concentration than the north. Further, the strong poleward alongshore currents advect the upwelled nutrients away from the southern and central parts of the coast to the north, thereby controlling the biological community over the Somali region. This abundant locally upwelled and remotely advected nutrients support the enhanced growth of diatoms in the northern part of the transect as earlier observed from in situ measurements. However, limited nutrients allow smaller phytoplankton communities to grow in the southern and central sections. We show that nitrate is the primary limiting nutrient for the phytoplankton growth in the central and southern parts of the Somalia coast.
Process‐Based Simulation of Aerosol‐Cloud Interactions in a One‐Dimensional Cirrus Model
Authors: Kärcher B. 
Published: March 2020

AbstractA new microphysical cirrus model to simulate ice crystal nucleation, depositional growth, and gravitational settling is described. The model tracks individual simulation ice particles in a vertical column of air and allows moisture and heat profiles to be affected by turbulent diffusion. Ice crystal size‐ and supersaturation‐dependent deposition coefficients are employed in a one‐dimensional model framework. This enables the detailed simulation of microphysical feedbacks influencing the outcome of ice nucleation processes in cirrus. The use of spheroidal water vapor fluxes enables the prediction of primary ice crystal shapes once microscopic models describing the vapor uptake on the surfaces of cirrus ice crystals are better constrained. Two applications addressing contrail evolution and cirrus formation demonstrate the potential of the model for advanced studies of aerosol‐cirrus interactions. It is shown that supersaturation in, and microphysical and optical properties of, cirrus are affected by variable deposition coefficients. Vertical variability in ice supersaturation, ice crystal sedimentation, and high turbulent diffusivity all tend to decrease homogeneously nucleated ice number mixing ratios over time, but low ice growth efficiencies counteract this tendency. Vertical mixing induces a tendency to delay the onset of homogeneous freezing. In situations of sustained large‐scale cooling, natural cirrus clouds may often form in air surrounding persistent contrails.
Paleolakes in the Northwest Hellas Region, Mars: Implications for the Regional Geologic History and Paleoclimate
Authors: Zhao Jiannan , Xiao Long , Glotch Timothy D. 
Published: March 2020

AbstractHellas basin is one of the largest and oldest impact basins on the Martian surface. Its surrounding highland regions have undergone complicated geologic processes after the formation of Hellas basin. However, the geologic and climatic histories of the highlands surrounding Hellas are still unclear. Paleolakes provide us clues to answer these questions. In this study, we made a detailed investigation of paleolakes in the northwest Hellas region with high‐resolution imaging, topographic, and spectral data. A total of 64 paleolakes were identified with diameters larger than 4 km, in which 49 are newly reported. We calculated basic hydrologic parameters of the paleolakes and analyzed the sedimentary landforms, resurfacing processes, and aqueous minerals in the lake basins. Comprehensive analyses of the geomorphology, mineralogy, and age of the paleolakes revealed the geologic and climatic histories of the northwest Hellas region: a climate transition from warm and wet to semi‐arid happened in Noachian, and then lakes drained in a cold and dry climate in the early Hesperian, contemporary with or followed by a period of intense volcanic activity peaked around 3.3 Ga, and finally in the Amazonian, an extensive glacial event around 0.9 Ga resurfaced most of the paleolakes in the region south of 25°S. Our study also supports the existence of a “Hellas Ocean” and indicates that the Martian climate could have variations on regional scales and further studies are still needed to clarify the details.
Far‐UV Observations of Lunar Rayed Craters with LRO‐LAMP
Authors: Byron B. D. , Retherford K. D. , Greathouse T. K. , Wyrick D. , Cahill J. T. S. , Hendrix A. R. , Raut U. , Mandt K. E. , Denevi B. W. 
Published: March 2020

AbstractUsing data from the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP), we investigate the spectral properties of rayed craters in the far‐ultraviolet (FUV). Because LAMP is sensitive to the uppermost layer of the lunar surface and regolith grains, it is ideal for characterizing regolith maturity and space weathering products such as submicroscopic iron. We find that crater rays from a survey of the largest Copernican‐age craters have high Off‐band (155–190 nm)/On‐band (130–155 nm) albedo (Off/On) LAMP product ratios, consistent with immature regolith and low amounts of submicroscopic iron. The Off/On ratio of the highlands crater rays decreases linearly over time (0.095 per 100 My), and we use this trend to estimate the age of Jackson crater (~152 My). Some large young highlands craters (e.g., Tycho, Jackson, Giordano Bruno, and Necho) display lower ratio halos around the crater cavity, at regions where previous studies have suggested abundant impact melt exists. The lower Off/On ratio is likely due to the increased glass component of the regolith at these highlands regions, which would act to increase absorption at Off‐band wavelengths. We also find that ejecta blankets from large maria craters (e.g., Copernicus and Aristillus) have a similar Off/On ratio to the mature background highlands. This supports previous findings that determined that the rays from these craters are composed of highlands material excavated from beneath the maria and subsequently weathered to maturity.
Up to 70 THz bandwidth from an implanted Ge photoconductive antenna excited by a femtosecond Er:fibre laser
Authors: Singh Abhishek , Pashkin Alexej , Winnerl Stephan , Welsch Malte , Beckh Cornelius , Sulzer Philipp , Leitenstorfer Alfred , Helm Manfred , Schneider Harald 
Published: March 2020

AbstractPhase-stable electromagnetic pulses in the THz frequency range offer several unique capabilities in time-resolved spectroscopy. However, the diversity of their application is limited by the covered spectral bandwidth. In particular, the upper frequency limit of photoconductive emitters - the most widespread technique in THz spectroscopy – reaches only up to 7 THz in the regular transmission mode due to absorption by infrared-active optical phonons. Here, we present ultrabroadband (extending up to 70 THz) THz emission from an Au-implanted Ge emitter that is compatible with mode-locked fibre lasers operating at wavelengths of 1.1 and 1.55 μm with pulse repetition rates of 10 and 20 MHz, respectively. This result opens up the possibility for the development of compact THz photonic devices operating up to multi-THz frequencies that are compatible with Si CMOS technology.
Tomography of the source zone of the great 2011 Tohoku earthquake
Authors: Hua Yuanyuan , Zhao Dapeng , Toyokuni Genti , Xu Yixian 
Published: March 2020

AbstractThe mechanism and rupture process of the giant 2011 Tohoku-oki earthquake (Mw 9.0) are still poorly understood due to lack of permanent near-field observations. Using seismic arrival times recorded by dense seismograph networks on land and at ocean floor, we determine a detailed seismic tomography model of the megathrust zone beneath the Tohoku forearc. Our results show that the coseismic slip of the 2011 Tohoku-oki earthquake initiated at a boundary between a down-dip high-velocity anomaly and an up-dip low-velocity anomaly. The slow anomaly at shallow depths near the Japan trench may reflect low-rigidity materials that are close to the free surface, resulting in large slip and weak high-frequency radiation. Our new tomographic model can account for not only large slip near the trench but also weak high-frequency radiation from the shallow rupture areas.
Effects of route of administration on oxytocin-induced changes in regional cerebral blood flow in humans
Authors: Martins D. A. , Mazibuko N. , Zelaya F. , Vasilakopoulou S. , Loveridge J. , Oates A. , Maltezos S. , Mehta M. , Wastling S. , Howard M. , McAlonan G. , Murphy D. , Williams S. C. R. , Fotopoulou A. , Schuschnig U. , Paloyelis Y. 
Published: March 2020

AbstractCould nose-to-brain pathways mediate the effects of peptides such as oxytocin (OT) on brain physiology when delivered intranasally? We address this question by contrasting two methods of intranasal administration (a standard nasal spray, and a nebulizer expected to improve OT deposition in nasal areas putatively involved in direct nose-to-brain transport) to intravenous administration in terms of effects on regional cerebral blood flow during two hours post-dosing. We demonstrate that OT-induced decreases in amygdala perfusion, a key hub of the OT central circuitry, are explained entirely by OT increases in systemic circulation following both intranasal and intravenous OT administration. Yet we also provide robust evidence confirming the validity of the intranasal route to target specific brain regions. Our work has important translational implications and demonstrates the need to carefully consider the method of administration in our efforts to engage specific central oxytocinergic targets for the treatment of neuropsychiatric disorders.
Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency
Authors: Jiang Wentao , Sarabalis Christopher J. , Dahmani Yanni D. , Patel Rishi N. , Mayor Felix M. , McKenna Timothy P. , Van Laer Raphaël , Safavi-Naeini Amir H. 
Published: March 2020

AbstractEfficient interconversion of both classical and quantum information between microwave and optical frequency is an important engineering challenge. The optomechanical approach with gigahertz-frequency mechanical devices has the potential to be extremely efficient due to the large optomechanical response of common materials, and the ability to localize mechanical energy into a micron-scale volume. However, existing demonstrations suffer from some combination of low optical quality factor, low electrical-to-mechanical transduction efficiency, and low optomechanical interaction rate. Here we demonstrate an on-chip piezo-optomechanical transducer that systematically addresses all these challenges to achieve nearly three orders of magnitude improvement in conversion efficiency over previous work. Our modulator demonstrates acousto-optic modulation with $${V}_{\pi }$$

V

π

= 0.02 V. We show bidirectional conversion efficiency of $$1{0}^{-5}$$
1

0

−
5

with 3.3 μW red-detuned optical pump, and $$5.5 \%$$
5.5
%
with 323 μW blue-detuned pump. Further study of quantum transduction at millikelvin temperatures is required to understand how the efficiency and added noise are affected by reduced mechanical dissipation, thermal conductivity, and thermal capacity.