bluuebunny/crossref_metadata_2025 huggingface dataset:
Keeping the Pilot Happy—the Contribution of Research and Development
Authors: Morgan Morien
Published: March 2023

When asked to give the de Havilland Memorial Lecture I could have taken as my subject the general state of play in aerospace research and development, with special reference to what Farnborough and its outstations were up to. Geoffrey de Havilland was a Farnborough product—a fact of which we at the RAE are very proud—so such a theme might have been appropriate. But de Havilland was not only a gifted aircraft designer, he was also essentially a test pilot. The whole rather special atmosphere at Hatfield which he created and sustained—and which still survives his death—owes much to the fact that we had here in one man both a quite exceptional engineer and an experienced and highly critical pilot who was quite capable of evaluating his own products in the air. As a matter of interest, I have reproduced in Figs. 1(a), and 1(b), pages from one of his 1911 notebooks at Farnborough which have recently come to light; even in those early days the pilot/designer combination sings out.
A Study of the Spectral Gust Alleviation Factor
Authors: Huntley E.
Published: March 2023

A great deal of research effort is going into the measurement of turbulent air velocities in relation to aircraft flight. There is a continuing need to review our knowledge of aircraft responses to air turbulence in order to appreciate the significance of the new information as it becomes available and in order to demonstrate which parameters in the problem are of most importance and therefore deserving of the closest study.

At the present stage of aircraft development we can see dramatic changes in aircraft speed, size and shape. Increased aircraft size, speed and height of operation imply larger values of the gust mass parameter μg than hitherto; they also mean that structural flexibility is becoming increasingly significant. Change of shape towards the slender configuration involves us not only in new appraisals of aircraft aerodynamics, steady and unsteady, but also in different modes of structural distortion from those typical of current subsonic turbojet transport aircraft.
Effect of Environmental Forces on the Attitude of Gravity Orientated Satellites
Authors: Modi V. J. , Flanagan R. C.
Published: March 2023

There are several situations of practical importance where it is essential to maintain a satellite in a fixed orientation relative to the earth. Of the numerous methods proposed for such station keeping, gravity gradient stabilisation has gained considerable attention primarily due to the passive nature of the system. The pioneering work for pure gravity orientated satellites was carried out by Klemperer who obtained the exact solution for planar librations of a dumbbell satellite in circular orbit, and by Baker who found periodic solutions of the problem for small orbit eccentricity. Schechter attempted, with limited success, to extend Klemperer's solution to non-circular orbital motion by perturbation methods. Zlatousov et al and, more recently, Brereton and Modi successfully employed numerical methods, involving the use of the stroboscopic phase plane, to analyse motion in the large for orbits of arbitrary eccentricity.
The Analysis of Radial Flow Impellers by the Matrix Finite Element Method
Authors: Chan A. S. L. , Henrywood R. K.
Published: March 2023

The stress analysis of an axisymmetrical body under the influence of a field of centrifugal body force is of considerable importance to the design of rotating machinery. The classical problem of the rotating disc of uniform thickness was considered by Maxwell as long ago as 1850. For this, the simplifying assumption that the stresses are functions of the distance from the centre only, with no change across the thickness, was made. Since then, the same basic analysis has been extended to discs of conical and hyperbolical cross-section profile, with or without a central hole, references to which may be found in a number of text books. The analysis of a disc with an elliptical cross-section was published by Chree in 1895. The solution for a disc of constant thickness has been refined to allow stress variation across the thickness. Although these solutions, in common with many analytical solutions in the theory of elasticity, do not satisfy all the boundary conditions exactly, they serve as very good approximations in practice.
The significance of propulsion in commercial aircraft productivity
Authors: Torell Bruce N.
Published: March 2023

You can pick up almost any history of aviation—from the early times to the present—and read of the exploits and adventures of pilots and their planes. Sir Charles Kingsford-Smith and his Fokker, Charles Lindbergh and his Ryan, Amelia Earhart and her Lockheed. We who have technical interests in aviation know that Kingsford- Smith and Lindbergh depended on their Whirlwinds, and Miss Earhart on a Wasp, but the popular stories often fail to make that point.

In more modern times, the engines are equally vital but sometimes get overlooked. Once, when a new jet aircraft was being announced at a press briefing, an airline officer breathlessly described the aircraft, showed artists’ concepts of the cabin and flight deck, and talked at length of the systems and subsystems. After an hour-long description, he called on his audience of reporters, and then he got his come-uppance from an engine man’s point of view. A reporter at the back of the room was recognised, and asked: ‘And what is this aircraft going to be? A glider?’ The by now red-faced official had neglected to mention the powerplants.
Finite deflection of sandwich panels resting on elastic supports
Authors: Ng S. F.
Published: March 2023

Due to their high strength to weight ratio, sandwich panels have become increasingly popular in various areas of structural design. This is particularly true with the aerospace industry where high strength low density materials play an important role in the fabrication of major structural components. Along with the continual quest for strong lightweight structures, recent optimisation methods in structural design have led to a re-examination of the validity of the traditional conservative designs based on the usual linear assumptions of structural analysis and tend to adopt more realistic approaches incorporating geometric nonlinearity of the structure by using more exact finite-displacement, strain-displacement equations.
Do Classified Boards Deter Takeovers? Evidence from Merger Waves
Authors: John Kose , Kadyrzhanova Dalida , Lee Sangho
Published: March 2023

We exploit the arrival of industry-wide synergistic merger waves to identify whether classified boards deter takeover bids. In a stylized model, we show that when target classified boards are costly to bidders, their negative effect on takeover likelihood should be more pronounced during merger waves. Using a sample of takeover bids in the United States between 1990 and 2016, we find strong evidence supporting this prediction. The results are robust to accounting for the benefits of classified boards and controlling for other antitakeover provisions. Our findings suggest that classified boards effectively reduce a firm’s exposure to the takeover market.
Bayesian optimization of massive material injection for disruption mitigation in tokamaks
Authors: Pusztai I. , Ekmark I. , Bergström H. , Halldestam P. , Jansson P. , Hoppe M. , Vallhagen O. , Fülöp T.
Published: March 2023

A Bayesian optimization framework is used to investigate scenarios for disruptions mitigated with combined deuterium and neon injection in ITER. The optimization cost function takes into account limits on the maximum runaway current, the transported fraction of the heat loss and the current quench time. The aim is to explore the dependence of the cost function on injected densities, and provide insights into the behaviour of the disruption dynamics for representative scenarios. The simulations are conducted using the numerical framework Dream (Disruption Runaway Electron Analysis Model). We show that, irrespective of the quantities of the material deposition, multi-megaampere runaway currents will be produced in the deuterium–tritium phase of operations, even in the optimal scenarios. However, the severity of the outcome can be influenced by tailoring the radial profile of the injected material; in particular, if the injected neon is deposited at the edge region it leads to a significant reduction of both the final runaway current and the transported heat losses. The Bayesian approach allows us to map the parameter space efficiently, with more accuracy in favourable parameter regions, thereby providing us with information about the robustness of the optima.
Legitimate child protection interventions and the dimension of confidence: A comparative analysis of populations views in six European countries
Authors: Loen Mathea , Skivenes Marit
Published: March 2023

The legitimacy of welfare state institutions is a key question in public policy research. In this study we examine population’s confidence in child protection systems, the role of institutional context and moral alignment. Analysing representative samples of survey data (N=6,043) of citizens in six European countries (Czechia, England, Finland, Norway, Poland and Romania), we find that overall people express confidence in their child protection system. Differences between populations are correlated with institutional context, i.e. the type of child protection system in place – that is, if people live in a country with a risk-oriented system or a family service-oriented system. People’s view on their moral alignment with the system (or not) only shows minor differences in support of interventions. However, a tendency towards polarisation is detected in Finland and Norway with clear differences in support of interventions that restrict parental rights: individuals who state they are in alignment with the system favour stronger interventions than those who say they are not.
Outcomes of truncal valve replacement in neonates and infants: a meta-analysis
Authors: Hardy William A. , Kang Lillian , Turek Joseph W. , Rajab T. Konrad
Published: March 2023

Background:

Infants with truncus arteriosus typically undergo repair by repurposing the truncal valve as the neo-aortic valve and using a valved conduit homograft for the neo-pulmonary valve. In cases where the native truncal valve is too insufficient for repair, it is replaced, but this is a rare occurrence with a paucity of data, especially in the infant population. Here, we conduct a meta-analysis to better understand the outcomes of infant truncal valve replacement during the primary repair of truncus arteriosus.

Methods:

We systematically reviewed PubMed, Scopus, and CINAHL for all studies reporting infant (<12 months) truncus arteriosus outcomes between 1974 and 2021. Exclusion criteria were studies which did not report truncal valve replacement outcomes separately. Data extracted included valve replacement type, mortality, and reintervention. Our primary outcome was early mortality, and our secondary outcomes were late mortality and reintervention rates.

Results:

Sixteen studies with 41 infants who underwent truncal valve replacement were included. The truncal valve replacement types were homografts (68.8%), mechanical valves (28.1%), and bioprosthetic valves (3.1%). Overall early mortality was 49.4% (95% CI: 28.4–70.5). The pooled late mortality rate was 15.3%/year (95% CI: 5.8–40.7). The overall rate of truncal valve reintervention was 21.7%/year (95% CI: 8.4–55.7).

Conclusions:

Infant truncal valve replacement has poor early and late mortality as well as high rates of reintervention. Truncal valve replacement therefore remains an unsolved problem in congenital cardiac surgery. Innovations in congenital cardiac surgery, such as partial heart transplantation, are required to address this.
Risk perception of cardiovascular disease among Turkish adults: a cross-sectional study
Authors: Topçu Sevcan , Ardahan Melek
Published: March 2023

Aim:

The aim of the study was to determine in adults the risk perception for cardiovascular disease (CVD) and the associated factors.

Background:

CVDs are the leading cause of death globally. In adults, perceptions related to the risk for CVDs have a considerable effect on decision-making processes related to one’s own health.

Methods:

A cross-sectional study was conducted with 453 adult people from April to June 2019 in İzmir, Turkey. Data were collected with a sociodemographic characteristics questionnaire, perception of risk of heart disease scale (PRHDS), and health perception.

Findings:

The mean PRHDS score of adults was 48.88 ± 8.12. The risk perception for CVD was influenced by variables that were age, gender, education, marital status, employment status, health perception, familial cardiovascular disease history, chronic disease status, smoking status, and body mass index. Although CVDs are the most prominent cause of disease-related death in the world, risk perception for CVD was found to be low among the individuals included in this study. This finding indicates the importance of informing individuals about CVD risk factors, raising awareness, and training.
Unterstützte Kommunikation – ein Angebot für alle?
Authors: Schüler Maren , Hänel-Faulhaber Barbara
Published: March 2023

Zusammenfassung. Partizipation und soziale Teilhabe hängen maßgeblich von erfolgreicher Kommunikation ab. Um den heterogenen kommunikativen Bedürfnissen von Kindern in inklusiven Kitagruppen gerecht zu werden, wurden pädagogische Fachkräfte in der Verwendung von lautsprachunterstützenden Gebärden fortgebildet. Die vorliegende Studie untersucht das Gebärdenlernverhalten der Kinder im Längsschnitt. Mit Fragebögen wurden 18 Monate nach Beginn der Implementierung Daten von 124 Kindern im Alter von 17 bis 70 Monaten erhoben. Es zeigte sich für lebensweltlich einsprachige bzw. lebensweltlich deutschsprachige (L1) und für bilingual aufwachsende Kinder (2L1) ein signifikanter Zusammenhang zwischen dem Sprachentwicklungsstand im Deutschen und der Anzahl der erlernten Gebärden: Höhere Punktzahlen in einem standardisierten Sprachscreening gingen mit einem größeren Gebärdenwortschatz einher. Zudem erlernten Kinder mit einem frühen Zweitspracherwerb des Deutschen im Durchschnitt mehr Gebärden als L1- und 2L1-Kinder mit einem vergleichbaren deutschen Sprachniveau. Folglich erwerben Kinder sowohl mit geringen als auch guten Sprachkompetenzen in inklusiven Kitagruppen durch Modeling Gebärden. So kann die Basis für eine weitere gemeinsame Kommunikationsform geschaffen werden, von der auch Kinder, die Deutsch als frühe Zweitsprache erwerben, profitieren könnten.
Measurements of Aerosol Particle Size Distributions and INPs Over the Southern Ocean in the Late Austral Summer of 2017 on Board the R/V Mirai: Importance of the Marine Boundary Layer Structure
Authors: Miyakawa Takuma , Taketani Fumikazu , Tobo Yutaka , Matsumoto Kazuhiko , Yoshizue Momoka , Takigawa Masayuki , Kanaya Yugo
Published: March 2023

The Southern Ocean (SO) is a unique region with rich ecosystems and minimal anthropogenic and terrestrial natural impacts especially during austral summer. We conducted measurements and sampling of aerosol particles to investigate the characteristics and role of aerosol particles in cloud formation on Japanese research vessel Mirai over the SO in the late austral summer of 2017. Observations of air masses with minimal terrestrial impacts indicated that bimodal aerosol particle size distributions were mostly observed over the SO and relative abundances of two modes varied with the changes in the structure of the marine boundary layer (MBL) such as surface mixing layer. As the local minimum diameter between two modes (DH) is considered a critical size for cloud‐droplet activation in the MBL, we analyzed the aerosol particles with diameter larger than DH (CNAcc) as a proxy for cloud condensation nuclei. Variations in the concentrations of aerosol particles with diameter larger than 300 nm were accounted for by the sea‐spray source function, whereas it substantially underestimated those of CNAcc. This implies the significance of the nonsea‐spray sources of CNAcc in the MBL over the SO. The concentrations of ice nucleating particles (NINPs) active at −25°C were 20–100 m−3, consistent with recent observations over the summertime SO. The observational evidence of very low NINPs relative to the CNAcc concentrations (40–110 cm−3) over a wide area of the SO is important for predicting the effects of cloud radiative properties on the radiative balances over the SO using climate models.
Increased Utilization of Storm Surge Barriers: A Research Agenda on Estuary Impacts
Authors: Orton Philip , Ralston David , van Prooijen Bram , Secor David , Ganju Neil , Chen Ziyu , Fernald Sarah , Brooks Bennett , Marcell Kristin
Published: March 2023

Rising coastal flood risk and recent disasters are driving interest in the construction of gated storm surge barriers worldwide, with current studies recommending barriers for at least 11 estuaries in the United States alone. Surge barriers partially block estuary‐ocean exchange with infrastructure across an estuary or its inlet and include gated areas that are closed only during flood events. They can alter the stratification and salt intrusion, change sedimentary systems, and curtail animal migration and ecosystem connectivity, with impacts growing larger with increasing gate closures. Existing barriers are being used with increasing frequency due to sea level rise. New barrier proposals typically come with maximum closure frequency recommendations, yet the future adherence to them is uncertain. Given that the broader environmental effects and coupled‐human dynamics of surge barriers are not well‐understood, we present an interdisciplinary research agenda for this increasingly prevalent modification to our coastal zone.
Retro‐Foredeep Basin Evolution in Taiwan: Zircon U‐Pb and Hf Isotope Constraints From the Coastal Range
Authors: Chen Tsai‐Wei , Chu Mei‐Fei , Chen Wen‐Shan , Chung Sun‐Lin , Lee Hao‐Yang , Iizuka Yoshiyuki
Published: March 2023

The evolution of the Taiwan orogen, an active arc–continent collision zone between the North Luzon Arc (NLA) and the Eurasian continent, is recorded in arc volcanic and sedimentary rocks from the Taiyuan retro‐foredeep basin of the Coastal Range, eastern Taiwan. Arc volcanism in the northern NLA experienced a magmatic culmination at 9–7 Ma and a cessation at 5.3–4.3 Ma, based on new U‐Pb zircon ages. Young zircon U‐Pb ages (1.74, 1.58, and <1.2 Ma) and low Hf isotope signatures also indicate that three biotite‐bearing lapilli tuff layers deposited in the retro‐foredeep basin are associated with eruptions of the Lutao volcano in the southern NLA. NLA volcanism terminated progressively from ∼5.3 to <1.2 Ma in response to a southward‐propagating collision zone that followed the uplift of the orogenic wedge by <3 myr. The detrital zircon U‐Pb age spectra suggest no significant shift in provenance during the Plio‐Pleistocene period and indicate that the synorogenic sediments in the Taiyuan Basin were mainly derived from the Yuli Belt, a Miocene accretionary complex in the eastern Taiwan orogen. The accumulation rate of synorogenic deposits varies from 0.53 to 5.14 km/myr, with an abrupt increase at ∼2 Ma. This new rate is higher than the previously proposed rates and that of the pro‐foreland basin to the west, suggesting asymmetric and rapid uplift of the Taiwan orogen.
The Effects of the Upper Atmosphere and Corona on the Solar Wind Interaction With Venus
Authors: Ma Y. , Combi M. R. , Tenishev V. , Shou Y. , Bougher S.
Published: March 2023

Since Venus has no substantial planetary magnetic field, the fast‐flowing solar wind plasma interacts directly with its ionosphere, upper atmosphere, and corona. The thermal atmosphere and hot oxygen corona of Venus are expected to play essential roles in the interaction process. To quantify their effects, we combine three major state‐of‐the‐art three‐dimensional numerical models, including (a) The Venus thermosphere general circulation model (VTGCM), (b) The adaptive mesh particle simulator (AMPS), and (c) A multi‐species Magnetohydrodynamics (MHD) model of Venus based on Block Adaptive Tree Solar‐wind Roe Upwind Scheme. The global multi‐species MHD model is used to simulate the planet's interaction with the ambient solar wind, where the background neutral densities are provided by VTGCM and AMPS. Using the above‐mentioned numerical models, the effect of the upper atmosphere and corona on solar wind driven ion escape rates are examined for three typical solar cycle conditions, including solar maximum, solar median, and solar minimum conditions. The model results suggest that even though the hot oxygen corona only has a minor effect on the ion density profiles in the ionosphere, it can enhance ion loss rate up to ∼25% for high solar activity.
A Geodynamic Investigation of Plume‐Lithosphere Interactions Beneath the East African Rift
Authors: Rajaonarison Tahiry A. , Stamps D. Sarah , Naliboff John , Nyblade Andrew , Njinju Emmanuel A.
Published: March 2023

The force balance that drives and maintains continental rifting to breakup is poorly understood. The East African Rift (EAR) provides an ideal natural laboratory to elucidate the relative role of plate driving forces as only lithospheric buoyancy forces and horizontal mantle tractions act on the system. Here, we employ high‐resolution 3D thermomechanical models to test whether: (a) the anomalous, rift‐parallel surface deformation observed by Global Navigation Satellite System (GNSS) data in the EAR are driven by viscous coupling to northward mantle flow associated with the African Superplume, and (b) the African Superplume is the dominant source mechanism of anomalous rift‐parallel seismic anisotropy beneath the EAR. We calculate Lattice Preferred Orientations (LPO) and surface deformation from two types of mantle flow: (a) a scenario with multiple plumes constrained by shear wave tomography and (b) a single superplume model with northward boundary condition to simulate large‐scale flow. Comparison of calculated LPO with observed seismic anisotropy, and surface velocities with GNSS and plate kinematics reveal that there is a better fit with the superplume mantle flow model, rather than the tomography‐based (multiple plumes) model. We also find a relatively better fit spatially between observed seismic anisotropy and calculated LPO with the superplume model beneath northern and central EAR, where the superplume is proposed to be shallowest. Our results suggest that the viscous coupling of the lithosphere to northward mantle flow associated with the African Superplume drives most of the rift‐parallel deformation and is the dominant source of the first‐order pattern of the observed seismic anisotropy in the EAR.
Laboratory Wave and Stress Measurements Quantify the Aerodynamic Sheltering in Extreme Winds
Authors: Tan Peisen , Smith Andrew W. , Curcic Milan , Haus Brian K.
Published: March 2023

In strong winds, air flow detaches from the ocean surface in the lee of wave crests and creates a low‐pressure zone on the wave’s leeward face. The pressure difference between the wave’s rear and front face modulates the momentum input from wind to waves. Numerical wave models parameterize this effect using a so‐called sheltering coefficient. However, its value and dependence on wind speed are not well understood, particularly with background swell waves. To bridge this gap, we conducted laboratory experiments with winds up to Category 4 hurricane force blown over various mechanically generated wave conditions (pure wind sea, mixed waves with directional spreading, and monochromatic unidirectional waves) and measured the wind, waves, and stress at a sufficient frequency to resolve wind‐wave variability over the long‐wave phase. We analyze the results in the context of Jeffreys’s sheltering theory and find two regimes: (a) from low‐to‐moderate wind forcing (10 m s−1 < U10 < 33 m s−1), the aerodynamic sheltering increases with wind speed, consistent with previous studies; (b) in hurricane conditions (U10 > 33 m s−1), the aerodynamic sheltering decreases with wind at a rate depending on wave state. Further, we isolate the short wind waves from the longer paddle waves and find that the aerodynamic sheltering by longer waves leads to a phase‐dependent variability of the short wind‐waves’ local steepness, which is evidenced by the sheltering coefficient’s value derived from wind and wave measurements. Our results emphasize the need for further measurements of aerodynamic sheltering and improving its representation in models.
Global and Regional Characteristics of Radially Outward Propagating Tropical Cyclone Diurnal Pulses
Authors: Zhang Xinyan , Ditchek Sarah D. , Corbosiero Kristen L. , Xu Weixin
Published: March 2023

The radially outward propagating, cloud top cooling, diurnal pulse (DP) is a prominent feature in tropical cyclones (TCs) that has important implications for changes in TC structure and intensity. By using an objective identification algorithm, this study characterizes DPs over various ocean basins and examines their environmental conditions and convective structures. DPs occur on 52% of TC days globally and the occurrence frequency exhibits significant regional variability. The Northwest Pacific (NWP) has the highest DP frequency (60%) and shares the largest fraction of DPs worldwide (34%). The median duration and propagation distance of DPs are 12–15 hr and 500–600 km, respectively. Although the mean propagation speed of DPs is 11–13 m s−1, persistent DPs (lasting >15 hr) mostly propagate at speeds similar to internal inertial gravity waves (5–10 m s−1). Additionally, the longer the pulse duration, the stronger the pulse amplitude. Further, most DPs initiate in the inner core overnight, in phase with inner‐core deep convection. Inner‐core cold clouds, precipitation, and lightning are all markedly enhanced on DP days compared to non‐DP days. Interestingly, the DP signal significantly weakens and becomes slower while propagating through the 200–400‐km annulus during 09–12 local time (LT). Finally, DPs are more likely to occur over warm sea surface temperatures (SSTs), in low shear, and with a moist mid‐to‐upper troposphere. SST plays an important role in DP development over all basins, while shear and humidity are less important in the Northeast Pacific (NEP) and North Atlantic (NA) basins.
Spatial and Longitudinal Distributions of Total Carbon, Nitrogen and Sulfur Together With Water‐Soluble Major Ions in Marine Aerosols Collected From the Western Paciﬁc and Southern Ocean
Authors: Kunwar Bhagawati , Pokhrel Ambarish , Niwai Takeji , Kawamura Kimitaka
Published: March 2023

To explore the latitudinal distributions, sources and formation mechanisms of total carbon (TC), nitrogen (TN), sulfur (TS) and water‐soluble major ions (Na+, Cl−, SO42−, K+, nss‐SO42−, NH4+, NO3−, and MSA−), marine aerosol samples were collected over the Western Pacific (WP) and Southern Ocean (SO) from November 1994 to February 1995. Concentrations of TC ranged 30–390 ng m−3 (av. 190 ng m−3) over the SO, which are six times lower than those (1,200 ng m−3) over the WP, whereas concentrations of TN (av. 83 ng m−3) in the SO are three times lower than those (av. 232 ng m−3) over the WP. The highest concentrations of TC and TN were observed near New Zealand (7,000 and 720 ng m−3, respectively), suggesting a continental influence over the marine atmosphere. NO3−, tracer of anthropogenic sources, showed higher concentrations over the WP, whereas NH4+ concentrations over the SO are higher than the WP. The latter may be associated with penguin‐derived guano droppings from Antarctica. The concentration trends and statistical analysis demonstrate that the formation mechanisms of MSA− over the SO and WP is different. We found a strong correlation between MSA− and liquid water content (LWC) over the WP, suggesting the heterogenous aqueous phase production of MSA−, whereas aqueous phase reaction is less important over the SO. The strong correlation (R2 = 0.97) between nss‐Ca2+ and ss‐Ca2+ together with their similar relative abundances demonstrates an influence of CaCO3 eroded from coral reefs and shells and subsequent emission to the atmosphere by bubble bursting process.
Effects of Elevated Ozone Exposure on Regional Meteorology and Air Quality in China Through Ozone‐Vegetation Coupling
Authors: Jin Zhipeng , Yan Dan , Zhang Zihan , Li Mengmeng , Wang Tijian , Huang Xin , Xie Min , Li Shu , Zhuang Bingliang
Published: March 2023

Ozone is a phytotoxic pollutant that could damage the vegetation growth and lead to complicated impacts on air quality through meteorological and biogeochemical feedbacks. This study implements a semi‐empirical parameterization regarding the impacts of ozone exposure on photosynthesis rate and stomatal resistance into the Noah‐Multi‐parameterization (Noah‐MP) dynamic vegetation module of Weather Research and Forecasting with Chemistry (WRF/Chem) model. The gaseous dry deposition and biogenic emission algorithms are also coupled with Noah‐MP to enable the ozone‐vegetation coupling. This model reproduces the near‐surface meteorology, air pollutants and vegetation physiology in China, with a spatial correlation coefficient more than 0.9 and normalized mean bias from −0.19 to 0.42. The optimized model also improves the simulations of vegetation physiology (e.g., a reduction of model error by 18%–32%) and ozone dry deposition velocity. The elevated ozone damages plant photosynthesis, and decreases the national gross primary productivity (−28.85%) and leaf area index (−17.41%). The plant transpiration and surface heat flux, as well as air temperature (e.g., up to +0.16°C in summer) and other associated meteorological variables are also altered, finally contributing to 0.49 μg m−3 increase of surface ozone. Otherwise, the suppressed vegetation LAI and biogenic emissions, as well as the lower dry deposition velocity in response to the ozone‐vegetation coupling contribute to the remaining ozone changes by −1.07 μg m−3 and 1.18 μg m−3, jointly constituting the complicated ozone‐vegetation feedbacks on air quality. Our results highlight the necessity of including the ozone‐vegetation coupling in models for reliable prediction of regional climate and air quality.
Reconstructing Long‐Term Forest Cover in China by Fusing National Forest Inventory and 20 Land Use and Land Cover Data Sets
Authors: Xia Xiaosheng , Xia Jiangzhou , Chen Xiuzhi , Fan Lei , Liu Shuguang , Qin Yuanwei , Qin Zhangcai , Xiao Xiangming , Xu Wenfang , Yue Chao , Yue Xu , Yuan Wenping
Published: March 2023

As an important type of terrestrial carbon sink, forests play a critical role in offsetting anthropogenic fossil fuel CO2 emissions which should help nations to achieve carbon neutrality goals worldwide. According to National Forest Inventory (NFI), China has experienced substantial increases in forest cover by benefiting from national afforestation projects initiated in the l980s. However, none of the current land use and land cover (LULC) data sets can reproduce the long‐term changes of forest cover derived from NFI in China. Here, by combining NFI and 20 LULC data sets, we developed a new method of reconstructing historical forest cover in China from 1980 to 2015 at 5‐year intervals. The new forest cover data set can accurately reproduce the historical changes of forest cover in China during this period. Validated against 3851 field survey samples covering the study period of 1985–2015, the data sets show high accuracy with overall accuracy varying from 76.9% to 99.4%. Accurate long‐term forest cover maps have great potential for use in estimating terrestrial carbon, tracking forest management, and other scientific research studies.
Ecosystem Metabolism Is the Dominant Source of Carbon Dioxide in Three Young Boreal Cascade‐Reservoirs (La Romaine Complex, Québec)
Authors: Barbosa Pedro M. , Bodmer Pascal , Stadler Masumi , Rust Felipe , Tremblay Alain , del Giorgio Paul A.
Published: March 2023

The impoundment of rivers for multipurpose reservoirs has significant consequences to the carbon cycle, one of the most relevant being the increase in greenhouse gases emissions. Reservoirs have been shown to be net sources of such gases to the atmosphere, emitting between 0.8 and 1.08 Pg carbon dioxide (CO2) equivalents per year. Even though emission estimates have become common, less is known about the processes driving this CO2 excess, a prerequisite for understanding and ultimately predicting and managing CO2 emissions from reservoirs. In the present study, we aimed at exploring ecosystem metabolism (gross primary production, ecosystem respiration, and net ecosystem production [NEP]) and its environmental drivers in three young hydroelectric reservoirs in a cascade configuration but with distinctive morphometries (shape, depth, and size). By combining our metabolic measurements with a hydrological mass balance approach, we quantified the relative contributions of internal (ecosystem metabolism) versus external sources (tributaries and groundwater) to the reservoir surface diffusive CO2 emissions. There was a predominance of net heterotrophy in all sites, and metabolism played a key role in fueling CO2 fluxes in all three reservoirs, NEP alone being able to account for the measured fluxes in approximately 50% of all sites. Internal production was thus the main process explaining total reservoir CO2 diffusive emissions (∼100%), with groundwater and tributaries contributing similarly but more modestly (∼9% each). Our results contribute to our understanding of the processes underlying boreal reservoir carbon footprints, and in particular, for apportioning the emissions can be attributed to the reservoir itself.
Simulating the Transport and Rupture of Pollen in the Atmosphere
Authors: Subba Tamanna , Zhang Yingxiao , Steiner Allison L.
Published: March 2023

Pollen, one type of primary biological aerosol particle (PBAP), is emitted from the terrestrial biosphere and can undergo physical changes in the atmosphere via particle rupture. To examine the fate of pollen and its atmospheric processing, a pollen emission and transport scheme is coupled to the Weather Research and Forecasting Model with Chemistry (WRF‐Chem). We simulate the emission of pollen and its impacts on the cloud properties and precipitation in the Southern Great Plains from 12 to 19 April 2013, a period with both high pollen emissions and convective activity. We conduct a suite of ensemble runs that simulate primary pollen and three different pollen rupture mechanisms that generate subpollen particles, including (a) high humidity‐induced surface rupture, (b) high humidity‐induced in‐atmosphere plus surface rupture, and (c) lightning‐induced rupture, where in‐cloud and cloud‐to‐ground lightning strikes trigger pollen rupture events. When relative humidity is high (>80%), coarse primary pollen (∼1 μg m−3) is converted into fine subpollen particles (∼1.2e−4 μg m−3), which produces 80% more subpollen particles than lightning‐induced rupture. The in‐atmosphere humidity‐driven rupture predominantly produces subpollen particles, which is further enhanced during a frontal thunderstorm. During strong convection, vertical updrafts lift primary pollen and subpollen particles (∼0.5e−4 μg m−3) to the upper troposphere (∼12 km) and laterally transports the ruptured pollen in the anvil top outflow. In regions of high pollen and strong convection, ruptured pollen can influence warm cloud formation by decreasing low cloud (<4 km) cloud water mixing ratios and increasing ice phase hydrometeors aloft (>10 km).
Specifying High Altitude Electrons Using Low‐Altitude LEO Systems: Updates to the SHELLS Model
Authors: Boyd A. J. , Green J. C. , O’Brien T. P. , Claudepierre S. G.
Published: March 2023

We describe a new version of the SHELLS model, which specifies the outer electron belt environment as observed by the Van Allen Probes using the Kp Index and data from Polar‐orbiting Operational Environmental Satellites and the Meteorological Operational satellites as inputs. The updated model combines the radial, angular and energy dependence into a single neural network, allowing for specification of the electron environment for a set of user input energy, L‐shell and Bmirror values. We demonstrate that the model can accurately reproduce the outer electron radiation belt dynamics using both out‐of‐sample data from the Van Allen Probes and measurements from the Combined X‐ray Dosimeter instrument on GPS. This updated model will provide valuable characterization of the internal charging hazard for non‐GEO orbits, particularly in the post‐Van Allen Probes era.
Probabilistic Sensitivity Analysis With Dependent Variables: Covariance‐Based Decomposition of Hydrologic Models
Authors: Gao Yifu , Sahin Abdullah , Vrugt Jasper A.
Published: March 2023

Variance‐based analysis has emerged as method of choice for quantifying the sensitivity of the output, y, of a scalar‐valued square‐integrable function, f ∈ L2(), to its d ≥ 1 input variables, x = {x1, …, xd}, with support . The prototype of this approach, Sobol's method is a generalization of the analysis of variance (ANOVA) to d > 2 independent input variables and decomposes y, as sum of elementary functions of zeroth‐, first‐, second‐, up to dth‐order. This independence assumption is mathematically convenient but may not be borne out of the causal or correlational relationships between the x's. This paper is concerned with variance‐based sensitivity analysis (SA) for correlated input variables, for example, multivariate dependencies in a posterior parameter distribution. We use high‐dimensional model representation (HDMR) of Li et al. (2010, https://doi.org/10.1021/jp9096919), Li and Rabitz (2012, https://doi.org/10.1007/s10910-011-9898-0) and replace Sobol's elementary functions with so‐called component functions with unknown expansion coefficients to disentangle the structural, correlative and total contribution of input factors. We contrast the default HDMR methodology with cubic B‐splines and sequential coefficient estimation against its successor, HDMRext of Li and Rabitz (2012, https://doi.org/10.1007/s10910-011-9898-0), which uses polynomial component functions with an extended orthonormalized basis. Benchmark experiments confirm that HDMR and HDMRext parse out the structural and correlative contributions of input factors to the model output and infer an optimal experimental design with parameter correlation. Our last study applies HDMRext to probabilistic SA of a watershed model. The multivariate posterior parameter distribution supports model emulation and yields sensitivity indices that pertain to measured discharge data.
Single-shot ultrafast terahertz photography
Authors: Dong Junliang , You Pei , Tomasino Alessandro , Yurtsever Aycan , Morandotti Roberto
Published: March 2023

Multidimensional imaging of transient events has proven pivotal in unveiling many fundamental mechanisms in physics, chemistry, and biology. In particular, real-time imaging modalities with ultrahigh temporal resolutions are required for capturing ultrashort events on picosecond timescales. Despite recent approaches witnessing a dramatic boost in high-speed photography, current single-shot ultrafast imaging schemes operate only at conventional optical wavelengths, being suitable solely within an optically-transparent framework. Here, leveraging on the unique penetration capability of terahertz radiation, we demonstrate a single-shot ultrafast terahertz photography system that can capture multiple frames of a complex ultrafast scene in non-transparent media with sub-picosecond temporal resolution. By multiplexing an optical probe beam in both the time and spatial-frequency domains, we encode the terahertz-captured three-dimensional dynamics into distinct spatial-frequency regions of a superimposed optical image, which is then computationally decoded and reconstructed. Our approach opens up the investigation of non-repeatable or destructive events that occur in optically-opaque scenarios.
Rewired m6A epitranscriptomic networks link mutant p53 to neoplastic transformation
Authors: Xu An , Liu Mo , Huang Mo-Fan , Zhang Yang , Hu Ruifeng , Gingold Julian A. , Liu Ying , Zhu Dandan , Chien Chian-Shiu , Wang Wei-Chen , Liao Zian , Yuan Fei , Hsu Chih-Wei , Tu Jian , Yu Yao , Rosen Taylor , Xiong Feng , Jia Peilin , Yang Yi-Ping , Bazer Danielle A. , Chen Ya-Wen , Li Wenbo , Huff Chad D. , Zhu Jay-Jiguang , Aguilo Francesca , Chiou Shih-Hwa , Boles Nathan C. , Lai Chien-Chen , Hung Mien-Chie , Zhao Zhongming , Van Nostrand Eric L. , Zhao Ruiying , Lee Dung-Fang
Published: March 2023

N6-methyladenosine (m6A), one of the most prevalent mRNA modifications in eukaryotes, plays a critical role in modulating both biological and pathological processes. However, it is unknown whether mutant p53 neomorphic oncogenic functions exploit dysregulation of m6A epitranscriptomic networks. Here, we investigate Li-Fraumeni syndrome (LFS)-associated neoplastic transformation driven by mutant p53 in iPSC-derived astrocytes, the cell-of-origin of gliomas. We find that mutant p53 but not wild-type (WT) p53 physically interacts with SVIL to recruit the H3K4me3 methyltransferase MLL1 to activate the expression of m6A reader YTHDF2, culminating in an oncogenic phenotype. Aberrant YTHDF2 upregulation markedly hampers expression of multiple m6A-marked tumor-suppressing transcripts, including CDKN2B and SPOCK2, and induces oncogenic reprogramming. Mutant p53 neoplastic behaviors are significantly impaired by genetic depletion of YTHDF2 or by pharmacological inhibition using MLL1 complex inhibitors. Our study reveals how mutant p53 hijacks epigenetic and epitranscriptomic machinery to initiate gliomagenesis and suggests potential treatment strategies for LFS gliomas.
Four distinct network patterns of supramolecular/polymer composite hydrogels controlled by formation kinetics and interfiber interactions
Authors: Nakamura Keisuke , Kubota Ryou , Aoyama Takuma , Urayama Kenji , Hamachi Itaru
Published: March 2023

Synthetic composite hydrogels comprising supramolecular fibers and covalent polymers have attracted considerable attention because their properties are similar to biological connective tissues. However, an in-depth analysis of the network structures has not been performed. In this study, we discovered the composite network can be categorized into four distinct patterns regarding morphology and colocalization of the components using in situ, real-time confocal imaging. Time-lapse imaging of the network formation process reveals that the patterns are governed by two factors, the order of the network formation and the interactions between the two different fibers. Additionally, the imaging studies revealed a unique composite hydrogel undergoing dynamic network remodeling on the scale of a hundred micrometers to more than one millimeter. Such dynamic properties allow for fracture-induced artificial patterning of a network three dimensionally. This study introduces a valuable guideline to the design of hierarchical composite soft materials.
Phytochrome B photobodies are comprised of phytochrome B and its primary and secondary interacting proteins
Authors: Kim Chanhee , Kwon Yongmin , Jeong Jaehoon , Kang Minji , Lee Ga Seul , Moon Jeong Hee , Lee Hyo-Jun , Park Youn-Il , Choi Giltsu
Published: March 2023

Phytochrome B (phyB) is a plant photoreceptor that forms a membraneless organelle called a photobody. However, its constituents are not fully known. Here, we isolated phyB photobodies from Arabidopsis leaves using fluorescence-activated particle sorting and analyzed their components. We found that a photobody comprises ~1,500 phyB dimers along with other proteins that could be classified into two groups: The first includes proteins that directly interact with phyB and localize to the photobody when expressed in protoplasts, while the second includes proteins that interact with the first group proteins and require co-expression of a first-group protein to localize to the photobody. As an example of the second group, TOPLESS interacts with PHOTOPERIODIC CONTROL OF HYPOCOTYL 1 (PCH1) and localizes to the photobody when co-expressed with PCH1. Together, our results support that phyB photobodies include not only phyB and its primary interacting proteins but also its secondary interacting proteins.
Excitons in mesoscopically reconstructed moiré heterostructures
Authors: Zhao Shen , Li Zhijie , Huang Xin , Rupp Anna , Göser Jonas , Vovk Ilia A. , Kruchinin Stanislav Yu. , Watanabe Kenji , Taniguchi Takashi , Bilgin Ismail , Baimuratov Anvar S. , Högele Alexander
Published: March 2023

Moiré effects in vertical stacks of two-dimensional crystals give rise to new quantum materials with rich transport and optical phenomena that originate from modulations of atomic registries within moiré supercells. Due to finite elasticity, however, the superlattices can transform from moiré-type to periodically reconstructed patterns. Here we expand the notion of such nanoscale lattice reconstruction to the mesoscopic scale of laterally extended samples and demonstrate rich consequences in optical studies of excitons in MoSe2–WSe2 heterostructures with parallel and antiparallel alignments. Our results provide a unified perspective on moiré excitons in near-commensurate semiconductor heterostructures with small twist angles by identifying domains with exciton properties of distinct effective dimensionality, and establish mesoscopic reconstruction as a compelling feature of real samples and devices with inherent finite size effects and disorder. Generalized to stacks of other two-dimensional materials, this notion of mesoscale domain formation with emergent topological defects and percolation networks will instructively expand the understanding of fundamental electronic, optical and magnetic properties of van der Waals heterostructures.
BioASQ-QA: A manually curated corpus for Biomedical Question Answering
Authors: Krithara Anastasia , Nentidis Anastasios , Bougiatiotis Konstantinos , Paliouras Georgios
Published: March 2023

The BioASQ question answering (QA) benchmark dataset contains questions in English, along with golden standard (reference) answers and related material. The dataset has been designed to reflect real information needs of biomedical experts and is therefore more realistic and challenging than most existing datasets. Furthermore, unlike most previous QA benchmarks that contain only exact answers, the BioASQ-QA dataset also includes ideal answers (in effect summaries), which are particularly useful for research on multi-document summarization. The dataset combines structured and unstructured data. The materials linked with each question comprise documents and snippets, which are useful for Information Retrieval and Passage Retrieval experiments, as well as concepts that are useful in concept-to-text Natural Language Generation. Researchers working on paraphrasing and textual entailment can also measure the degree to which their methods improve the performance of biomedical QA systems. Last but not least, the dataset is continuously extended, as the BioASQ challenge is running and new data are generated.