bluuebunny/crossref_metadata_2025 huggingface dataset:
On the receptivity of low-pressure turbine blades to external disturbances
Authors: Lengani D. , Simoni D. , Pralits J.O. , Đurović K. , De Vincentiis L. , Henningson D.S. , Hanifi A.
Published: March 2022

In the present work, the laminar–turbulent transition of the flow evolving around a low-pressure turbine blade has been investigated. Direct numerical simulations have been carried out for two different free stream turbulence intensity (FSTI) levels to investigate the role of free stream oscillations on the evolution of the blade boundary layer. Emphasis is placed on identifying the mechanisms driving the formation and breakup of coherent structures in the high FSTI case and how these processes are affected by the leading-edge receptivity and/or by the continuous forcing in the blade passage. Proper orthogonal decomposition (POD) has been adopted to provide a clear statistical representation of the shape of the structures. Extended POD projections provided temporal and spanwise correlations that allowed us to identify dominant temporal structures and spanwise wavelengths in the transition process. The extended POD analysis shows that the structures on the pressure side are not related to what happens at the leading edge. The results on the suction side show that the modes defining the leading edge and the passage bases correlate with coherent structures responsible for the transition. The most energetic mode of the passage basis is strongly related to the most amplified wavelength in the boundary layer and breakup events leading to transition. Modes with a smaller spanwise wavelength belong to the band predicted by optimal disturbance theory, they amplify with a smaller gain in the rear suction side, and they show the highest degree of correlation between the passage region and the rear suction side.
On the wavenumber–frequency spectrum of the wall pressure fluctuations in turbulent channel flow
Authors: Yang Bowen , Yang Zixuan
Published: March 2022

Direct numerical simulations (DNS) of turbulent channel flows up to${Re}_{\tau} \approx 1000$are conducted to investigate the three-dimensional (consisting of streamwise wavenumber, spanwise wavenumber and frequency) spectrum of wall pressure fluctuations. To develop a predictive model of the wavenumber–frequency spectrum from the wavenumber spectrum, the time decorrelation mechanisms of wall pressure fluctuations are investigated. It is discovered that the energy-containing part of the wavenumber–frequency spectrum of wall pressure fluctuations can be well predicted using a similar random sweeping model for streamwise velocity fluctuations. To refine the investigation, we further decompose the spectrum of the total wall pressure fluctuations into the autospectra of rapid and slow pressure fluctuations, and the cross-spectrum between them. We focus on evaluating the assumption applied in many predictive models, that is, the magnitude of the cross-spectrum is negligibly small. The present DNS shows that neglecting the cross-spectrum causes a maximum error up to 4.7 dB in the subconvective region for all Reynolds numbers under test. Our analyses indicate that the approximation of neglecting the cross-spectrum needs to be applied carefully in the investigations of acoustics at low Mach numbers, in which the subconvective components of wall pressure fluctuations make important contributions to the radiated acoustic power.
Traditional Kenyan herbal medicine: exploring natural products’ therapeutics against schistosomiasis
Authors: Ndegwa Fidensio K. , Kondam Chaitanya , Aboagye Samuel Y. , Esan Taiwo E. , Waxali Zohra Sattar , Miller Margaret E. , Gikonyo Nicholas K. , Mbugua Paul K. , Okemo Paul O. , Williams David L. , Hagen Timothy J.
Published: March 2022

Praziquantel (PZQ) remains the only drug of choice for the treatment of schistosomiasis, caused by parasitic flatworms. The widespread use of PZQ in schistosomiasis endemic areas for about four decades raises concerns about the emergence of resistance of Schistosoma spp. to PZQ under drug selection pressure. This reinforces the urgency in finding alternative therapeutic options that could replace or complement PZQ. We explored the potential of medicinal plants commonly used by indigenes in Kenya for the treatment of various ailments including malaria, pneumonia, and diarrhoea for their antischistosomal properties. Employing the Soxhlet extraction method with different solvents, seven medicinal plants Artemisia annua, Ajuga remota, Bredilia micranta, Cordia africana, Physalis peruviana, Prunus africana and Senna didymobotrya were extracted. Qualitative phytochemical screening was performed to determine the presence of various phytochemicals in the plant extracts. Extracts were tested against Schistosoma mansoni newly transformed schistosomula (NTS) and adult worms and the schistosomicidal activity was determined by using the adenosine triphosphate quantitation assay. Phytochemical analysis of the extracts showed different classes of compounds such as alkaloids, tannins, terpenes, etc., in plant extracts active against S. mansoni worms. Seven extracts out of 22 resulted in <20% viability against NTS in 24 h at 100 μg/ml. Five of the extracts with inhibitory activity against NTS showed >69.7% and ≥72.4% reduction in viability against adult worms after exposure for 24 and 48 h, respectively. This study provides encouraging preliminary evidence that extracts of Kenyan medicinal plants deserve further study as potential alternative therapeutics that may form the basis for the development of the new treatments for schistosomiasis.
Electron acceleration from the interaction of three crossed parallel Alfvén waves
Authors: Daiffallah K.
Published: March 2022

We study the nonlinear interaction of three parallel Alfvén wave packets (AWPs) in an initially uniform plasma using 2.5-dimensional particle-in-cell (PIC) numerical simulations. We aim to help to explain the observation of suprathermal electrons by the collision of multiple Alfvén waves in regions where these waves are trapped like the IAR (Ionospheric Alfvén Resonator), Earth radiation belts or coronal magnetic loops. In the context of the acceleration by the parallel Alfvén waves interactions (APAWI) process that has been described by Mottez (Ann. Geophys., vol. 30, issue 1, 2012, pp. 81–95; J. Plasma Phys., vol. 81, issue 1, 2015, p. 325810104), the interaction of two parallel Alfvén waves (AWs) generates longitudinal density modulations and parallel electric fields at the APAWI crossing region that can accelerate particles effectively in the direction of the background magnetic field. Our simulations show that when a third parallel AWP of different initial position arrives at the APAWI crossing region, it gives rise to a strong parallel electron beam (

$V \sim 5\text {--}7 V_{Te}$

) at longitudinal cavity density gradients. We suggest that velocity drift from an outgoing AW generates interface waves in the transverse direction, which allows propagating waves to develop parallel electric fields by the phase mixing process when

$k_{\perp }^{-1}$

of the wavy density gradient (oblique gradient) is in the range of the electron inertial length

$c/\omega _{p0}$

.
Association of intellectual disability with violent and sexual crime and victimization: a population-based cohort study
Authors: Latvala Antti , Tideman Magnus , Søndenaa Erik , Larsson Henrik , Butwicka Agnieszka , Fazel Seena , Lichtenstein Paul
Published: March 2022

Background

Intellectual disability (ID) is associated with violent and sexual offending and victimization, but the importance of neuropsychiatric comorbidity and severity of disability remains unclear.

Methods

In a register-based cohort study of people born in Sweden 1980–1991 (n = 1 232 564), we investigated associations of mild and moderate/severe ID with any, violent and sexual crimes, and with assault victimization, stratified by comorbid autism and attention deficit hyperactivity disorder (ADHD). We defined ID by attendance at a special school or registered diagnosis and obtained data on criminal convictions and injuries or deaths due to assaults from nationwide registers until end of 2013.

Results

Compared to people without ID, autism or ADHD, men and women with mild or moderate/severe ID and comorbid ADHD had elevated risks of violent crimes [range of hazard ratios (HRs) 4.4–10.4] and assault victimization (HRs 2.0–7.7). Women with mild ID without comorbidities or with comorbid autism also had elevated risks of violent crimes and victimization (HRs 1.8–4.6) compared to women without ID, autism or ADHD. The relative risks of sexual offending and victimization were elevated in men and women with ID without comorbidities (HRs 2.6–12.7). The highest risks for sexual offending in men (HRs 9.4–11.0) and for sexual assault victimization in women (HRs 11.0–17.1) related to ID and comorbid ADHD.

Conclusions

The elevated risk of violent offending and assault victimization in people with ID is largely explained by comorbid ADHD, whereas ID is independently associated with sexual crimes and victimization, even though absolute risks are low.
Insights from real-time comprehension of Spanish verbal tense in children with developmental language disorder: An eye-tracking study
Authors: Christou Spyros , Andreu Llorenç , Coloma Carmen Julia , Guerra Ernesto , Araya Claudia , Rodriguez-Ferreiro Javier , Sanz-Torrent Monica
Published: March 2022

The comprehension of Spanish verbal future and past tense of children with developmental language disorder (DLD) was evaluated in an eye-tracking experiment with 96 Spanish- and Catalan-speaking participants distributed in 4 groups: 24 children with DLD (Mage7.8 years), 24 children with the same chronological age (Mage7.8), 24 children with the same linguistic level (Mage6.8 years), and 24 adults (Mage22.5 years). Empirical data revealed that children with DLD can comprehend verbal tense, at least in the present experimental conditions. Based on the empirical results and despite some minor differences between the DLD group and the chronological control group, we suggest that tense morphology comprehension in DLD might be more typical than what is generally considered. Additionally, we propose that verbal comprehension difficulties in children with DLD might be less related to the lack of understanding of specific morphological markers, and more to an accumulation of difficulty which leads to a linguistic processing slowdown.
The marketplace of rationalizations
Authors: Williams Daniel
Published: March 2022

Recent work in economics has rediscovered the importance of belief-based utility for understanding human behaviour. Belief ‘choice’ is subject to an important constraint, however: people can only bring themselves to believe things for which they can find rationalizations. When preferences for similar beliefs are widespread, this constraint generates rationalization markets, social structures in which agents compete to produce rationalizations in exchange for money and social rewards. I explore the nature of such markets, I draw on political media to illustrate their characteristics and behaviour, and I highlight their implications for understanding motivated cognition and misinformation.
The League of Nations’ Collaboration with an ‘International Public’, 1919–1939
Authors: Seidenfaden Emil Eiby
Published: March 2022

This article analyses the distinctive characteristics of how the League of Nations sought to publicly legitimise itself from 1919 to 1939. Discussing the work of the Information Section of the League Secretariat, it traces the organisational development of this section throughout the interwar years and argues that a preference of ‘collaboration’ through liaison with influential members of the public in the League's member states permeated this section's work, and that this strategy was, in the eyes of League officials, necessitated by the tight political constraints the Secretariat was subjected to rather than the result of an inherent ‘elitism’ of the officials.
A Bridge between Art and Philosophy: The Case of Thomas Hobbes
Authors: Skinner Quentin
Published: March 2022

The leading question raised by the rhetoricians of classical antiquity was how to speak with maximum persuasive force. You must find the means, they answered, to enable your readers to see what you are arguing. This initially gave rise to a preoccupation with visual metaphors and other so-called figures of speech. Much later, with the development of the printed book, this also led to the practice of inserting actual figures into books to provide visual summaries of their arguments. Here, one pioneer was Thomas Hobbes, and this article offers an interpretation of the frontispieces he included in his two main works of political philosophy, De cive and Leviathan. The moral Hobbes aims to convey is that we have no alternative but to submit to the protecting power of the sovereign state if we wish to live in security and peace.
Cluster Analysis of Combined EDS and EBSD Data to Solve Ambiguous Phase Identifications
Authors: Parish Chad M.
Published: March 2022

A common problem in analytical scanning electron microscopy (SEM) using electron backscatter diffraction (EBSD) is the differentiation of phases with distinct chemistry but the same or very similar crystal structure. X-ray energy dispersive spectroscopy (EDS) is useful to help differentiate these phases of similar crystal structures but different elemental makeups. However, open, automated, and unbiased methods of differentiating phases of similar EBSD responses based on their EDS response are lacking. This paper describes a simple data analytics-based method, using a combination of singular value decomposition and cluster analysis, to merge simultaneously acquired EDS + EBSD information and automatically determine phases from both their crystal and elemental data. I use hexagonal TiB2 ceramic contaminated with multiple crystallographically ambiguous but chemically distinct cubic phases to illustrate the method. Code, in the form of a Python 3 Jupyter Notebook, and the necessary data to replicate the analysis are provided as Supplementary material.
COVID-19 testing trends: pre-radiation and throughout cancer care
Authors: Messing Ian , Felps Miriam , Goyal Sharad , Rao Yuan James , Schreiner Katherine , Scully Diana , Ojong-Ntui Martin , Huynh-Le Minh-Phuong
Published: March 2022

Introduction:

Patients presenting for radiation therapy (RT) at a single institution were analysed regarding treatment delays and disparities during the coronavirus disease 2019 (COVID-19) pandemic.

Methods:

The study was conducted at an urban multidisciplinary cancer centre. In April 2020, the institution’s radiation oncology department implemented universal COVID-19 screening protocols prior to RT initiation. COVID-19 testing information on cancer patients planned for RT from 04/2020 to 01/2021 was reviewed. Trends of other lifetime COVID-19 testing and overall care delays were also studied.

Results:

Two hundred and fifty-four consecutive cancer patients received RT. Median age was 63 years (range 24–94) and 57·9% (n = 147) were Black. Most (n = 107, 42·1%) patients were insured through Medicare. 42·9% (n = 109) presented with stage IV disease. One (0·4%) asymptomatic patient tested positive for COVID-19 pre-RT. The cohort received 975 lifetime COVID-19 tests (median 3 per patient, range 1–18) resulting in 29 positive test results across 21 patients. Sixteen patients had RT delays. Identifying as Hispanic/Latino was associated with testing positive for COVID-19 (p = 0·015) and RT delay (p = 0·029).

Conclusion:

Most patients with cancer planned for RT tested negative for COVID-19 and proceeded to RT without delay. However, increased testing burden, delays in diagnostic workup and testing positive for COVID-19 may intensify disparities affecting this urban patient population.
Becoming virtually real: using the Virtual Environment for Radiotherapy Training (VERT™) platform for the summative assessment of performance in a palliative radiotherapy treatment technique
Authors: Williams Andrew , Blane Shelley
Published: March 2022

Introduction:

Direct observation in the radiotherapy clinic remains the primary method for the assessment of procedural skills. But with increasing automation and reductions in clinical placement time during the recent pandemic, the role of summative, simulation-based assessment is being revisited. The aim of this article is to share early experiences of using Virtual Environment for Radiotherapy Training (VERT) in the assessment of a palliative, parallel pair, external beam treatment delivery technique in a new pre-registration undergraduate programme.

Methods:

Eight first-year students completed a campus-based individual virtual assessment using virtual patient plans representing metastatic disease in the brain and pelvis and late-stage primary lung tumours. Performance was logged on a 25-item checklist for pre and post-procedure checks and treatment delivery tasks.

Results:

All eight students participated in the assessment with seven students (87·5%) achieving a pass grade at first attempt. The course team observed that participants demonstrated a range of skills and abilities and were able to compare and contrast individual approaches to patient positioning. Specific feed-forward action points were also highlighted as areas for students’ to focus on during their second placement. The project also identified logistical benefits for assessment teams.

Conclusions:

While these experiences are a single snapshot, a VERT simulation-based summative assessment is feasible and identified benefits included controlled observation and structured feedback on individual performance and scheduling pressure reductions for clinical teams. However, more work is needed to determine the psychometric qualities and predictability of performance in more complex techniques.
The Acknowledge–Normalize–Partner (ANP) Framework: A novel empathic communication tool for oncology nurses
Authors: Kramer Dana , Chow Kimberly , Davis Mary Elizabeth , Nelson Judith E. , Anderson Kelley , Okpako Molly , Bernal Camila , Malisse Catherine E. , Goldberg Jessica I.
Published: March 2022

Objective

To describe the development and implementation of a novel tool designed to enhance nurse–patient communication in a major academic cancer center, which nurses can learn quickly, incorporate into their primary palliative care practice, and broadly disseminate in order to improve the patient experience.

Method

An evidence-based empathic communication tool and educational program were designed to provide essential skills to oncology nurses in having discussions with patients about their personal values. Evaluation included nurse focus groups, pre- and post-course evaluations and interviews, and patient questionnaires.

Results

Nurses were satisfied with the educational program and found the communication tool effective in a variety of clinical situations including discussions about personal values. Patients reported increased occurrences of these discussions when nurses utilized the framework (97% vs. 58%, p < 0.0001) and a higher quality of clinician communication (mean [SD] from 0 = very worst to 10 = very best: 7.18 [2.3] vs. 5.04 [2.9], p = 0.001).

Significance of results

Skilled, empathic communication is an essential component of high-quality primary palliative care. Oncology nurses are well suited to lead communication and provide this care as part of an interprofessional team. The training and tool described here are targeted and efficient, and prepare nurses to respond skillfully to emotion while facilitating important discussions about patient values.
Opposing abortion in a feminist paradise: Conservative rhetoric in Iceland
Authors: Sigvaldason Gunnar , Ómarsdóttir Silja Bára
Published: March 2022

This article addresses the conservative opposition to Iceland’s recently liberalised abortion laws. It argues that the opposition belongs to a long and rich history of conservatives willing to employ diverse measures to oppose progress. It further claims that the rhetoric employed has strong roots in the conservative tradition. This is demonstrated by the fact that the discourse in Iceland fits within Hirschman’s analytical framework, through which he analyses the main arguments of conservatives in the past. Icelandic conservatives argued that the proposed legislation would lead to the perverse effect that healthy foetuses would be aborted, that the legislation was futile, as the system was already well-functioning, and that it would jeopardise women by giving them the sole responsibility of deciding whether to terminate a pregnancy. The article sheds light on the underlying resistance to women’s bodily autonomy and right to self-determination. It also illustrates the importance of hierarchy and conservatism’s opposition to equality that is perceived to be taken too far. In light of global trends, where conservatives have tried to implement policies that are hostile towards women and women’s interests, it is important to explore national contexts where legislative success has been achieved despite global backlash.
Individual Career Transitions of German Olympians During the COVID-19 Pandemic
Authors: Leisterer Sascha , Lautenbach Franziska
Published: March 2022

Abstract. The COVID-19 pandemic can affect individual career transitions in athletes preparing for the Olympic Games (OG). This study reconstructs German Olympians’ career transitions while preparing for the postponed OG in Tokyo, applying the Scheme of Change for Sport Psychology Practice (SCSPP). Eleven (age: M ± SD = 26.81 ± 2.92; three females) athletes provide insights into their career transitions according to the SCSPP framework. The athletes report changes (e. g., training, professional status, missing competitions) related to emotional tensions (e. g., relief vs. disappointment) and the effects on their decision-making processes (i. e., initial coping, acceptance, adaptation). The Olympians develop identities, commonly experience relief, and describe their optimism toward Tokyo 2021. No interviewee wants to quit because of COVID-19. While preparing for Tokyo 2021, the Olympians use emotion- (e. g., vacation) and problem-oriented coping (e. g., new routines). Based on our results, we discuss recommendations for sport psychology practice.
The Stratospheric Diurnal Cycle in COSMIC GPS Radio Occultation Data: Scientific Applications
Authors: Leroy S. S. , Gleisner H.
Published: March 2022

The diurnal cycle throughout the stratosphere is analyzed by applying Bayesian interpolation to Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System radio occultation (RO) data and three scientific applications of the analysis are introduced. First, the migrating thermal tides are analyzed with unprecedented accuracy and precision, with an uncertainty in the analysis of the vertically propagating tides ranging from 0.1 in the lower stratosphere to 0.6 K in the upper stratosphere for an individual month of RO data and with an uncertainty in a 10‐year climatological diurnal cycle a factor of 10 less. Moreover, the midlatitude trapped tide is found to be smaller than what is produced by an atmospheric model and lags the model in phase, a likely consequence of a faulty parameterization of eddy diffusivity in the upper stratosphere. Second, a clear signal of solar cycle influence on the diurnal cycle is evident in this analysis, but whether the cause is the systematic bias of ionospheric residual associated with RO retrieval or it is an actual atmospheric phenomenon is less clear. Third, RO satellites and missions that obtain inadequate coverage of the diurnal cycle will be biased by under‐sampling it, whether or not subsampling weather forecasts is used to removal sampling error. The analysis of the diurnal cycle in COSMIC RO data can be used to diagnose the systematic sampling error incurred by incomplete coverage of the diurnal cycle, which is of the order of 0.2 K for a Metop‐based RO climatology.
Linking the Subsurface Indian Ocean Dipole to Central Pacific ENSO
Authors: Song G. , Ren R. C.
Published: March 2022

We identified a remote linkage from the Central Pacific (CP) El Niño–Southern Oscillation (ENSO) to the subsurface Indian Ocean dipole (Sub‐IOD) occurring in winter‐to‐spring. Although most Sub‐IOD events co‐occur with a surface Indian Ocean dipole (IOD) in autumn, some Sub‐IOD events develop independently in winter‐to‐spring. These spring Sub‐IODs are usually accompanied by a CP ENSO event that develops in the winter, peaks in early spring, and has a more westward‐located sea surface temperature anomaly over the central equatorial Pacific (around 180°E). The sea surface temperature anomaly and the accompanying surface zonal wind anomalie during these western CP El Niño (La Niña) events contributes to an anomalous descending (ascending) branch of the Walker circulation over the Indo‐Pacific region and easterly (westerly) anomalies over the equatorial Indian Ocean from winter to the following spring. This helps to trigger a positive (negative) Sub‐IOD event.
Storstrømmen and L. Bistrup Bræ, North Greenland, Protected From Warm Atlantic Ocean Waters
Authors: Rignot Eric , Bjork Anders , Chauche Nolwenn , Klaucke Ingo
Published: March 2022

Storstrømmen and L. Bistrup Bræ are 20‐ and 10‐km wide, surge type glaciers in North Greenland in quiescent phase that terminate in the southernmost floating ice tongue in East Greenland. Novel multi‐beam echo sounding data collected in August 2020 indicate a seabed at 350–400 m depth along a relatively uniform ice shelf front, 100 m deeper than expected, but surrounded by shallower terrain (<100 m) over a 30‐km wide region that blocks the access of warm, salty, subsurface Atlantic Intermediate Water (AIW) at +1.6°C. Conductivity temperature depth data reveal waters in front of the glaciers at −1.8°C not connected to AIW in the outer fjord, Dove Bugt. The recent grounding line retreat of the glaciers is attributed to glacier thinning at its ablation rate, with little influence of ocean waters, which illustrates the fundamental importance of knowing the bathymetry of glacial fjords.
Elucidating Coastal Ocean Carbon Transport Processes: A Novel Approach Applied to the Northwest North Atlantic Shelf
Authors: Rutherford Krysten , Fennel Katja
Published: March 2022

A latitudinal pattern in coastal air‐sea CO2 flux has emerged where mid‐and high‐latitude shelves act as net sinks and low‐latitude shelves as net sources to the atmosphere. Regional studies, however, report the mid‐latitude Scotian Shelf (SS) at the eastern Canadian seaboard acts as a large source of CO2, contradicting several global syntheses. Here, we combine observations and a regional biogeochemical model to explain, for the first time, how this net outgassing of CO2 is sustained. We employ a novel approach using passive dye tracers to estimate how carbonate properties change along dominant transport pathways. We show that cold, carbon‐rich subpolar North Atlantic water is a dominant endmember that warms and combines with low alkalinity (TA), carbon‐deplete freshwater from the Gulf of St. Lawrence, becoming oversaturated with CO2 on the SS. Our approach explicitly considers the 3‐dimensional nature of coastal ocean transport processes and should be applied to other shelf regions.
Exploring Ocean Circulation on Icy Moons Heated From Below
Authors: Bire Suyash , Kang Wanying , Ramadhan Ali , Campin Jean‐Michel , Marshall John
Published: March 2022

We numerically explore convection and general circulation of an ocean, encased in a spherical shell of uniform thickness, heated from below by a spatially uniform heat flux, and whose temperature at the upper surface is relaxed to the freezing point of water. The role of salt is not considered. We describe the phenomenology and equilibrium solutions across a broad range of two key non‐dimensional numbers: the natural Rossby number, a measure of the influence of rotation, and the ratio of inner to outer radius of the moon's ocean, a measure of the geometry of the moon's tangent cylinder. Two distinct regimes of circulation are identified, both dominated by Taylor columns aligned with the rotation axis—“plumes” and “rolls” which predominate inside and outside the tangent cylinder, respectively. Inside the tangent cylinder, convective plumes align with Taylor columns that extend from the bottom to the ice shell. The plumes energize geostrophic turbulence which in turn generates a general circulation consisting counter‐rotating zonal jets. Moreover, the plumes are efficient at transferring heat from the bottom to the surface, resulting in loss of heat from the ocean to the polar ice. If the plumes are suppressed rolls outside the tangent cylinder become the dominant mode of heat transfer resulting in equatorial cooling. We conclude that if moons such as Enceladus and Europa were to be predominantly heated from below, they will likely have a “Jovian‐like” circulation: an unstratified, turbulent, geostrophically controlled ocean with strong “Taylor column” behavior and a circulation dominated by counter‐rotating zonal jets.
Development of a Process‐Based N2O Emission Model for Natural Forest and Grassland Ecosystems
Authors: Ma Minna , Song Chaoqing , Fang Huajun , Zhang Jingbo , Wei Jing , Liu Shurong , Chen Xiuzhi , Zhang Kerou , Yuan Wenping , Lu Haibo
Published: March 2022

Forests and grasslands play a significant role in global nitrous oxide (N2O) emission, while a sophisticated model is missing to interpret the microbial processes involved in N2O production and consumption in these ecosystems. A new N2O emission model, MicN model, was developed for natural forest and grassland ecosystems by integrating with Integrated BIosphere Simulator (IBIS). This new model includes four major N2O correlated processes: autotrophic nitrification, heterotrophic nitrification, nitrifier denitrification and denitrifier denitrification. Thirty‐nine observation sites, including various forest and grassland ecosystem types, were selected to calibrate and validate IBIS‐MicN model. The IBIS‐MicN model explained 89% and 85% of observed daily variability in N2O emission for all calibration and validation sites, respectively. In addition, the model successfully predicted the concentrations of two important intermediates (i.e., ammonium and nitrate) for N2O production at nine validation sites. Compared with Forest‐DNDC model, IBIS‐MicN model performed better in simulating N2O emission, soil NH4+ and NO3−concentrations. At site scale, the simulated N2O emissions by IBIS‐MicN model positively correlated with annual mean soil temperature and annual precipitation, but negatively correlated with soil pH. This study provides an alternative model to estimate global N2O emission from natural forest and grassland ecosystems and to investigate corresponding environmental regulations.
Modeling Intra‐ and Interannual Variability of BVOC Emissions From Maize, Oil‐Seed Rape, and Ryegrass
Authors: Havermann Felix , Ghirardo Andrea , Schnitzler Jörg‐Peter , Nendel Claas , Hoffmann Mathias , Kraus David , Grote Rüdiger
Published: March 2022

Air chemistry is affected by the emission of biogenic volatile organic compounds (BVOCs), which originate from almost all plants in varying qualities and quantities. They also vary widely among different crops, an aspect that has been largely neglected in emission inventories. In particular, bioenergy‐related species can emit mixtures of highly reactive compounds that have received little attention so far. For such species, long‐term field observations of BVOC exchange from relevant crops covering different phenological phases are scarcely available. Therefore, we measured and modeled the emission of three prominent European bioenergy crops (maize, ryegrass, and oil‐seed rape) for full rotations in north‐eastern Germany. Using a proton transfer reaction–mass spectrometer combined with automatically moving large canopy chambers, we were able to quantify the characteristic seasonal BVOC flux dynamics of each crop species. The measured BVOC fluxes were used to parameterize and evaluate the BVOC emission module (JJv) of the physiology‐oriented LandscapeDNDC model, which was enhanced to cover de novo emissions as well as those from plant storage pools. Parameters are defined for each compound individually. The model is used for simulating total compound‐specific reactivity over several years and also to evaluate the importance of these emissions for air chemistry. We can demonstrate substantial differences between the investigated crops with oil‐seed rape having 37‐fold higher total annual emissions than maize. However, due to a higher chemical reactivity of the emitted blend in maize, potential impacts on atmospheric OH‐chemistry are only 6‐fold higher.
The Vertical Structure and Entrainment of Subglacial Melt Water Plumes
Authors: Burchard Hans , Bolding Karsten , Jenkins Adrian , Losch Martin , Reinert Markus , Umlauf Lars
Published: March 2022

Basal melting of marine‐terminating glaciers, through its impact on the forces that control the flow of the glaciers, is one of the major factors determining sea level rise in a world of global warming. Detailed quantitative understanding of dynamic and thermodynamic processes in melt‐water plumes underneath the ice‐ocean interface is essential for calculating the subglacial melt rate. The aim of this study is therefore to develop a numerical model of high spatial and process resolution to consistently reproduce the transports of heat and salt from the ambient water across the plume into the glacial ice. Based on boundary layer relations for momentum and tracers, stationary analytical solutions for the vertical structure of subglacial non‐rotational plumes are derived, including entrainment at the plume base. These solutions are used to develop and test convergent numerical formulations for the momentum and tracer fluxes across the ice‐ocean interface. After implementation of these formulations into a water‐column model coupled to a second‐moment turbulence closure model, simulations of a transient rotational subglacial plume are performed. The simulated entrainment rate of ambient water entering the plume at its base is compared to existing entrainment parameterizations based on bulk properties of the plume. A sensitivity study with variations of interfacial slope, interfacial roughness and ambient water temperature reveals substantial performance differences between these bulk formulations. An existing entrainment parameterization based on the Froude number and the Ekman number proves to have the highest predictive skill. Recalibration to subglacial plumes using a variable drag coefficient further improves its performance.
Correlate light–matter interactions in different spectral regimes
Authors: Gan Qiaoqiang
Published: March 2022

Using mid-infrared plasmons to trigger visible surface enhanced Raman spectroscopy signals within a nanocavity represents new opportunities for fundamental investigation of light–matter interaction within quantum regimes, requiring improved sensing capabilities enabled by well-designed nano/microstructures and characterization systems.
An orally available, brain penetrant, small molecule lowers huntingtin levels by enhancing pseudoexon inclusion
Authors: Keller Caroline Gubser , Shin Youngah , Monteys Alex Mas , Renaud Nicole , Beibel Martin , Teider Natalia , Peters Thomas , Faller Thomas , St-Cyr Sophie , Knehr Judith , Roma Guglielmo , Reyes Alejandro , Hild Marc , Lukashev Dmitriy , Theil Diethilde , Dales Natalie , Cha Jang-Ho , Borowsky Beth , Dolmetsch Ricardo , Davidson Beverly L. , Sivasankaran Rajeev
Published: March 2022

Huntington’s Disease (HD) is a progressive neurodegenerative disorder caused by CAG trinucleotide repeat expansions in exon 1 of the huntingtin (HTT) gene. The mutant HTT (mHTT) protein causes neuronal dysfunction, causing progressive motor, cognitive and behavioral abnormalities. Current treatments for HD only alleviate symptoms, but cerebral spinal fluid (CSF) or central nervous system (CNS) delivery of antisense oligonucleotides (ASOs) or virus vectors expressing RNA-induced silencing (RNAi) moieties designed to induce mHTT mRNA lowering have progressed to clinical trials. Here, we present an alternative disease modifying therapy the orally available, brain penetrant small molecule branaplam. By promoting inclusion of a pseudoexon in the primary transcript, branaplam lowers mHTT protein levels in HD patient cells, in an HD mouse model and in blood samples from Spinal Muscular Atrophy (SMA) Type I patients dosed orally for SMA (NCT02268552). Our work paves the way for evaluating branaplam’s utility as an  HD therapy, leveraging small molecule splicing modulators to reduce expression of dominant disease genes by driving pseudoexon inclusion.
Xenogeneic silencing strategies in bacteria are dictated by RNA polymerase promiscuity
Authors: Forrest David , Warman Emily A. , Erkelens Amanda M. , Dame Remus T. , Grainger David C.
Published: March 2022

Horizontal gene transfer facilitates dissemination of favourable traits among bacteria. However, foreign DNA can also reduce host fitness: incoming sequences with a higher AT content than the host genome can misdirect transcription. Xenogeneic silencing proteins counteract this by modulating RNA polymerase binding. In this work, we compare xenogeneic silencing strategies of two distantly related model organisms: Escherichia coli and Bacillus subtilis. In E. coli, silencing is mediated by the H-NS protein that binds extensively across horizontally acquired genes. This prevents spurious non-coding transcription, mostly intragenic in origin. By contrast, binding of the B. subtilis Rok protein is more targeted and mostly silences expression of functional mRNAs. The difference reflects contrasting transcriptional promiscuity in E. coli and B. subtilis, largely attributable to housekeeping RNA polymerase σ factors. Thus, whilst RNA polymerase specificity is key to the xenogeneic silencing strategy of B. subtilis, transcriptional promiscuity must be overcome to silence horizontally acquired DNA in E. coli.
Accelerating flash droughts induced by the joint influence of soil moisture depletion and atmospheric aridity
Authors: Qing Yamin , Wang Shuo , Ancell Brian C. , Yang Zong-Liang
Published: March 2022

The emergence of flash drought has attracted widespread attention due to its rapid onset. However, little is known about the recent evolution of flash droughts in terms of the speed of onset and the causes of such a rapid onset phase of flash droughts. Here, we present a comprehensive assessment of the onset development of flash droughts and the underlying mechanisms on a global scale. We find that 33.64−46.18% of flash droughts with 5-day onset of drying, and there is a significant increasing trend in the proportion of flash droughts with the 1-pentad onset time globally during the period 2000−2020. Flash droughts do not appear to be occurring more frequently in most global regions, just coming on faster. In addition, atmospheric aridity is likely to create a flash drought-prone environment, and the joint influence of soil moisture depletion and atmospheric aridity further accelerates the rapid onset of flash droughts.
Astrocytic phagocytosis contributes to demyelination after focal cortical ischemia in mice
Authors: Wan Ting , Zhu Wusheng , Zhao Ying , Zhang Xiaohao , Ye Ruidong , Zuo Meng , Xu Pengfei , Huang Zhenqian , Zhang Chunni , Xie Yi , Liu Xinfeng
Published: March 2022

Ischemic stroke can cause secondary myelin damage in the white matter distal to the primary injury site. The contribution of astrocytes during secondary demyelination and the underlying mechanisms are unclear. Here, using a mouse of distal middle cerebral artery occlusion, we show that lipocalin-2 (LCN2), enriched in reactive astrocytes, expression increases in nonischemic areas of the corpus callosum upon injury. LCN2-expressing astrocytes acquire a phagocytic phenotype and are able to uptake myelin. Myelin removal is impaired in Lcn2−/− astrocytes. Inducing re-expression of truncated LCN2(Δ2–20) in astrocytes restores phagocytosis and leads to progressive demyelination in Lcn2−/− mice. Co-immunoprecipitation experiments show that LCN2 binds to low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. Knockdown of Lrp1 reduces LCN2-induced myelin engulfment by astrocytes and reduces demyelination. Altogether, our findings suggest that LCN2/LRP1 regulates astrocyte-mediated myelin phagocytosis in a mouse model of ischemic stroke.
Sex-linked deubiquitinase establishes uniparental transmission of chloroplast DNA
Authors: Joo Sunjoo , Kariyawasam Thamali , Kim Minjae , Jin EonSeon , Goodenough Ursula , Lee Jae-Hyeok
Published: March 2022

Most sexual organisms inherit organelles from one parent, commonly by excluding organelles from the smaller gametes. However, post-mating elimination of organelles derived from one gamete ensures uniparental inheritance, where the underlying mechanisms to distinguish organelles by their origin remain obscure. Mating in Chlamydomonas reinhardtii combines isomorphic plus and minus gametes, but chloroplast DNA from minus gametes is selectively degraded in zygotes. Here, we identify OTU2p (otubain protein 2), encoded in the plus mating-type locus MT+, as the protector of plus chloroplast. Otu2p is an otubain-like deubiquitinase, which prevents proteasome-mediated degradation of the preprotein translocase of the outer chloroplast membrane (TOC) during gametogenesis. Using OTU2p-knockouts and proteasome inhibitor treatment, we successfully redirect selective DNA degradation in chloroplasts with reduced TOC levels regardless of mating type, demonstrating that plus-specific Otu2p establishes uniparental chloroplast DNA inheritance. Our work documents that a sex-linked organelle quality control mechanism drives the uniparental organelle inheritance without dimorphic gametes.
Role of mobile genetic elements in the global dissemination of the carbapenem resistance gene blaNDM
Authors: Acman Mislav , Wang Ruobing , van Dorp Lucy , Shaw Liam P. , Wang Qi , Luhmann Nina , Yin Yuyao , Sun Shijun , Chen Hongbin , Wang Hui , Balloux Francois
Published: March 2022

The mobile resistance gene blaNDM encodes the NDM enzyme which hydrolyses carbapenems, a class of antibiotics used to treat some of the most severe bacterial infections. The blaNDM gene is globally distributed across a variety of Gram-negative bacteria on multiple plasmids, typically located within highly recombining and transposon-rich genomic regions, which leads to the dynamics underlying the global dissemination of blaNDM to remain poorly resolved. Here, we compile a dataset of over 6000 bacterial genomes harbouring the blaNDM gene, including 104 newly generated PacBio hybrid assemblies from clinical and livestock-associated isolates across China. We develop a computational approach to track structural variants surrounding blaNDM, which allows us to identify prevalent genomic contexts, mobile genetic elements, and likely events in the gene’s global spread. We estimate that blaNDM emerged on a Tn125 transposon before 1985, but only reached global prevalence around a decade after its first recorded observation in 2005. The Tn125 transposon seems to have played an important role in early plasmid-mediated jumps of blaNDM, but was overtaken in recent years by other elements including IS26-flanked pseudo-composite transposons and Tn3000. We found a strong association between blaNDM-carrying plasmid backbones and the sampling location of isolates. This observation suggests that the global dissemination of the blaNDM gene was primarily driven by successive between-plasmid transposon jumps, with far more restricted subsequent plasmid exchange, possibly due to adaptation of plasmids to their specific bacterial hosts.
Structural basis of leukotriene B4 receptor 1 activation
Authors: Wang Na , He Xinheng , Zhao Jing , Jiang Hualiang , Cheng Xi , Xia Yu , Eric Xu H. , He Yuanzheng
Published: March 2022

Leukotriene B4 receptor 1 (BLT1) plays crucial roles in the acute inflammatory responses and is a valuable target for anti-inflammation treatment, however, the mechanism by which leukotriene B4 (LTB4) activates receptor remains unclear. Here, we report the cryo-electron microscopy (cryo-EM) structure of the LTB4 -bound human BLT1 in complex with a Gi protein in an active conformation at resolution of 2.91 Å. In combination of molecule dynamics (MD) simulation, docking and site-directed mutagenesis, our structure reveals that a hydrogen-bond network of water molecules and key polar residues is the key molecular determinant for LTB4 binding. We also find that the displacement of residues M1013.36 and I2717.39 to the center of receptor, which unlock the ion lock of the lower part of pocket, is the key mechanism of receptor activation. In addition, we reveal a binding site of phosphatidylinositol (PI) and discover that the widely open ligand binding pocket may contribute the lack of specificity and efficacy for current BLT1-targeting drug design. Taken together, our structural analysis provides a scaffold for understanding BLT1 activation and a rational basis for designing anti-leukotriene drugs.
Exploratory study reveals far reaching systemic and cellular effects of verapamil treatment in subjects with type 1 diabetes
Authors: Xu Guanlan , Grimes Tiffany D. , Grayson Truman B. , Chen Junqin , Thielen Lance A. , Tse Hubert M. , Li Peng , Kanke Matt , Lin Tai-Tu , Schepmoes Athena A. , Swensen Adam C. , Petyuk Vladislav A. , Ovalle Fernando , Sethupathy Praveen , Qian Wei-Jun , Shalev Anath
Published: March 2022

Currently, no oral medications are available for type 1 diabetes (T1D). While our recent randomized placebo-controlled T1D trial revealed that oral verapamil had short-term beneficial effects, their duration and underlying mechanisms remained elusive. Now, our global T1D serum proteomics analysis identified chromogranin A (CHGA), a T1D-autoantigen, as the top protein altered by verapamil and as a potential therapeutic marker and revealed that verapamil normalizes serum CHGA levels and reverses T1D-induced elevations in circulating proinflammatory T-follicular-helper cell markers. RNA-sequencing further confirmed that verapamil regulates the thioredoxin system and promotes an anti-oxidative, anti-apoptotic and immunomodulatory gene expression profile in human islets. Moreover, continuous use of oral verapamil delayed T1D progression, promoted endogenous beta-cell function and lowered insulin requirements and serum CHGA levels for at least 2 years and these benefits were lost upon discontinuation. Thus, the current studies provide crucial mechanistic and clinical insight into the beneficial effects of verapamil in T1D.
Promoter/enhancer-based controllability of regulatory networks
Authors: Devkota Prajwal , Wuchty Stefan
Published: March 2022

Understanding the mechanisms of tissue-specific transcriptional regulation is crucial as mis-regulation can cause a broad range of diseases. Here, we investigated transcription factors (TF) that are indispensable for the topological control of tissue specific and cell-type specific regulatory networks as a function of their binding to regulatory elements on promoters and enhancers of corresponding target genes. In particular, we found that promoter-binding TFs that were indispensable for regulatory network control regulate genes that are tissue-specifically expressed and overexpressed in corresponding cancer types. In turn, indispensable, enhancer-binding TFs were enriched with disease and signaling genes as they control an increasing number of cell-type specific regulatory networks. Their target genes were cell-type specific for blood and immune-related cell-types and over-expressed in blood-related cancers. Notably, target genes of indispensable enhancer-binding TFs in cell-type specific regulatory networks were enriched with cancer drug targets, while target genes of indispensable promoter-binding TFs were bona-fide targets of cancer drugs in corresponding tissues. Our results emphasize the significant role control analysis of regulatory networks plays in our understanding of transcriptional regulation, demonstrating potential therapeutic implications in tissue-specific drug discovery research.