bluuebunny/crossref_metadata_2025 huggingface dataset:
Full-waveform centroid moment tensor inversion of passive seismic data acquired at the reservoir scale
Authors: Liu Qiancheng , Waheed Umair bin , Borisov Dmitry , Simons Frederik J , Gao Fuchun , Williamson Paul
Published: April 2022

Passive seismic inversion at the reservoir scale offers the advantages of low cost, negligible environmental impact and the ability to probe a target area with low-frequency energy not afforded by even the most modern active-source seismic technology. In order to build starting models suitable for full-waveform wave speed tomography, characterization of earthquake sources is an indispensable first step. We present a workflow for the centroid moment tensor (CMT) inversion of seismic events identified in a passive seismic data set acquired by a large and dense array of three-component broad-band seismic sensors in a mountainous setting in the Himalayan foothills. The data set comprised 256 instruments operating for 2×4 months over an area of 8000 km2. An initial 3-D wave speed model was determined for the region via the analysis of first-arriving traveltime picks. Of the 2607 identified seismic events that were well recorded at frequencies between 0.2–50 Hz, 86 with magnitudes 1.3 ≤ M ≤ 3.0 initially had their CMT focal mechanisms determined by a waveform fitting procedure built on a Green’s function approach in a 1-D layered average wave speed model, for stations within an offset of 10 km, in the frequency range 0.2–1.4 Hz. Here, we obtain updated CMT mechanisms for the 86 events in that catalogue via multicomponent full-waveform inversion in the 3-D wave speed model. Our workflow includes automated data- and model-driven data selection using a combination of different metrics derived from signal-to-noise considerations and waveform-fitting criteria, and relies upon spectral-element simulations of elastic wave propagation in the 3-D wave speed model, honouring topography. Starting from the initial CMT solutions, we seek improvement to the data fit within the frequency band 0.5–2.5 Hz by minimizing the waveform difference between observed and synthetic data, while accommodating wave speed-model errors by allowing for small time-shifts. We balance uneven data coverage and tune their contributions via data-space weighting functions. We quantify the improvements to the data fit in terms of different metrics. We summarize the changes to the CMT solutions, and present and analyse the resulting catalogue for the region, including their breakdown into double-couple and non-double couple components, and their relation to mapped faults.
Polio by the Numbers—A Global Perspective
Authors: Badizadegan Kamran , Kalkowska Dominika A , Thompson Kimberly M
Published: April 2022

Background

Investments in national immunization programs and the Global Polio Eradication Initiative (GPEI) have resulted in substantial reductions in paralytic polio worldwide. However, cases prevented because of investments in immunization programs and GPEI remain incompletely characterized.

Methods

Using a global model that integrates polio transmission, immunity, and vaccine dynamics, we provide estimates of polio incidence and numbers of paralytic cases prevented. We compare the results with reported cases and estimates historically published by the World Health Organization.

Results

We estimate that the existence and use of polio vaccines prevented 5 million cases of paralytic polio for 1960–1987 and 24 million cases worldwide for 1988–2021 compared to a counterfactual world with no polio vaccines. Since the 1988 resolution to eradicate polio, our estimates suggest GPEI prevented 2.5–6 million cases of paralytic polio compared to counterfactual worlds without GPEI that assume different levels of intensity of polio vaccine use in routine immunization programs.

Conclusions

Analysis of historical cases provides important context for understanding and communicating the benefits of investments made in polio eradication. Prospective studies will need to explore the expected benefits of future investments, the outcomes of which will depend on whether and when polio is globally eradicated.
Analysis of Ceftazidime/Avibactam Use for Treating Carbapenem-Resistant Infections in Critically Ill Patients With Thermal or Inhalation Injuries
Authors: Martin Kelsey , Arif Faisal , Sultan-Ali Ibrahim , Velamuri Sai R , Hill David M
Published: April 2022

Rising antimicrobial resistance is a pressing public health concern. An increase in carbapenem-resistant organisms has led to increased use of novel antibiotics, such as ceftazidime/avibactam (CZ/AV). However, recent studies have shown increasing treatment failures and resistance rates associated with ceftazidime/avibactam use. The efficacy of CZ/AV has not been studied in patients with thermal or inhalation injuries, where pharmacokinetic derangements are common and patients are often subject to longer lengths of stay and several antimicrobial courses that may lead to higher resistance rates. The objective of this study was to evaluate the outcomes of patients with thermal and inhalation injuries including clinical success, the frequency of adverse effects, and emergence of resistance. In the 17 courses of CZ/AV evaluated, clinical success occurred in 71% (12/17) of courses. Enterobacter cloacae was the most commonly treated pathogen. Resistance developed in 18% (3/17) of courses, but follow-up sensitivities were not evaluable for every case. Although lower than desired, clinical success rates in this sample were similar to other reported populations treated with CZ/AV. However, the emergence of resistance occurred more frequently and was likely underreported in this sample. Although limited by its small sample size, this study emphasizes the concern of growing antimicrobial resistance among even novel antibiotics. Resistance can develop during the initial course, stressing the importance of infection prevention and antimicrobial stewardship. Furthermore, attention and resources should be given to proper pharmacokinetic analysis of medications given in severely ill, hypermetabolic populations.
Liquidity and Discipline. Bank due Diligence Over the Business Cycle
Authors: Cao Qingqing , Di Pietro Marco , Kokas Sotirios , Minetti Raoul
Published: April 2022

The quality of bank lending is increasingly viewed as a force driving the buildup and unfolding of crises. In a dynamic general equilibrium model, we show that banks’ access to liquidity and the values of loan portfolios govern banks’ incentives and effectiveness in producing information on loans. Consistent with granular loan-level evidence from US banks, the calibrated model predicts that loan due diligence deteriorates during expansions and intensifies during contractions. This countercyclicality attenuates investment and output effects of liquidity shocks but can moderately amplify loan quality shocks. Credit policies may dilute stabilizing effects of due diligence.
Seasonal and diurnal variation in ecosystem respiration and environmental controls from an alpine wetland in arid northwest China
Authors: Yao Hu , Peng Haijun , Hong Bing , Ding Hanwei , Hong Yetang , Zhu Yongxuan , Wang Jie , Cai Cheng
Published: April 2022

Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services. Understanding the dynamics of wetland carbon exchange is crucial for assessing carbon budgets and predicting their future evolution. Although many studies have been conducted on the effects of climate change on the ecosystem carbon cycle, little is known regarding carbon emissions from the alpine wetlands in arid northwest China. In this study, we used an automatic chamber system (LI-8100A) to measure ecosystem respiration (ER) in the Bayinbuluk alpine wetland in northwest China. The ER showed a significant bimodal diurnal variation, with peak values appearing at 16:30 and 23:30 (Beijing time, UTC + 8). A clear seasonal pattern in ER was observed, with the highest value (19.38 µmol m−2 s−1) occurring in August and the lowest value (0.11 µmol m−2 s−1) occurring in late December. The annual ER in 2018 was 678 g C m−2 and respiration during the non-growing season accounted for 13% of the annual sum. Nonlinear regression revealed that soil temperature at 5 cm depth and soil water content (SWC) were the main factors controlling the seasonal variation in ER. The diurnal variation in ER was mainly controlled by air temperature and solar radiation. Higher temperature sensitivity (Q10) occurred under conditions of lower soil temperatures and medium SWC (25% ≤ SWC ≤ 40%). The present study deepens our understanding of CO2 emissions in alpine wetland ecosystems and helps evaluate the carbon budget in alpine wetlands in arid regions.
Dynamics of gliotoxin and bis(methylthio)gliotoxin production during the course of Aspergillus fumigatus infection
Authors: Gomez-Lopez Alicia , Rueda Cristina , Pando Pozo Rebeca , Sanchez Gonzalez Luis Miguel
Published: April 2022

As recently described, fungal secondary metabolism activates during infection in response to a hostile host environment. Gliotoxin and bis(methylthio)gliotoxin are two recognized secondary metabolites produced by Aspergillus fumigatus with differential cytotoxicity and involved in virulence. We sought to describe the temporal dynamics of gliotoxin and bis(methylthio)gliotoxin during A. fumigatus progression to further explore their role in the infection. First, we optimized the production of the mycotoxins under different in vitro growth conditions and then specifically measured them using an UHPLC/PDA method. The analytical conditions were selected after testing different parameters such as extraction procedures, column type, and mobile phase composition. We found that gliotoxin and bis(methylthio)gliotoxin are differentially excreted to the extracellular media during the course of A. fumigatus infection regardless of the growth format tested. Dynamic profiles show an early production of gliotoxin, which, after reaching a maximum, decreases coinciding with the increase in the production of the inactive derivative bis(methylthio)gliotoxin. Presence of gliotoxin may indicate an early phase of fungal development, whereas detection of bis(methylthio)gliotoxin may correspond to a more advanced stage of infection. Our chromatographic method successfully characterizes these secondary metabolites. Thus, it may potentially be used to further understand Aspergillus infection.

Lay Summary

Aspergillus fumigatus secondary metabolites may contribute to fungal survival. A new chromatographic method was applied to simultaneously characterize two relevant metabolites. Presence of toxic gliotoxin may indicate an early phase of development, whereas the detection of the inactive derivate may represent an advanced infection stage.
Serendipitous discovery of radio flaring behaviour from a nearby M dwarf with MeerKAT
Authors: Andersson Alex , Fender Rob P , Lintott Chris J , Williams David R A , Driessen Laura N , Woudt Patrick A , van der Horst Alexander J , Buckley David A H , Motta Sara E , Rhodes Lauren , Eisner Nora L , Osten Rachel A , Vreeswijk Paul , Bloemen Steven , Groot Paul J
Published: April 2022

We report on the detection of MKT J174641.0−321404, a new radio transient found in untargeted searches of wide-field MeerKAT radio images centred on the black hole X-ray binary H1743−322. MKT J174641.0−321404 is highly variable at 1.3 GHz and was detected three times during 11 observations of the field in late 2018, reaching a maximum flux density of 590 ± 60 µJy. We associate this radio transient with a high proper motion, M dwarf star SCR 1746−3214 12 pc away from the Sun. Multiwavelength observations of this M dwarf indicate flaring activity across the electromagnetic spectrum, consistent with emission expected from dMe stars, and providing upper limits on quiescent brightness in both the radio and X-ray regimes. TESS photometry reveals a rotational period for SCR 1746−3214 of 0.2292 ± 0.0025 d, which at its estimated radius makes the star a rapid rotator, comparable to other low-mass systems. Dedicated spectroscopic follow up confirms the star as a mid-late spectral M dwarf with clear magnetic activity indicated by strong H α emission. This transient’s serendipitous discovery by MeerKAT, along with multiwavelength characterization, make it a prime demonstration of both the capabilities of the current generation of radio interferometers and the value of simultaneous observations by optical facilities such as MeerLICHT. Our results build upon the literature of M dwarfs’ flaring behaviour, particularly relevant to the habitability of their planetary systems.
Large-scale dynamics of winds driven by line force from a thin accretion disc
Authors: Zhu Yi , Bu De-Fu , Yang Xiao-Hong , Yuan Feng , Lin Wen-Bin
Published: April 2022

Winds play a significant role in active galactic nuclei feedback process. Previous simulations studying winds only focus on a small dynamical range. Therefore, it is unknown how far the winds can go and what the properties of the winds will be if they can move to large radii. We perform simulations to study the large-scale dynamics of winds driven by line force. We find that the properties of the winds depend on both black hole mass (MBH) and accretion disc luminosity. When the accretion disc luminosity is 0.6Ledd (Ledd being Eddington luminosity), independent of MBH, the winds have kinetic energy flux exceeding $1{{\ \rm per\ cent}} L_{\rm edd}$ and can escape from the black hole potential. For the case with the accretion disc luminosity equaling 0.3 Ledd, the strength of the winds decreases with the decrease of MBH. If MBH decreases from 109 to 106 solar mass (M⊙), the winds kinetic energy flux decreases from ∼0.01 Ledd to ∼10−6Ledd. In case of $M_{\rm BH}\ge 10^7 \, \mathrm{M}_\odot$, winds can escape from black hole potential. In the case of $M_{\rm BH}=10^6 \, \mathrm{M}_\odot$, the winds cannot escape. We find that for the ultra-fast winds observed in hard X-ray bands, the observed dependence of the mass flux and the kinetic energy flux on accretion disc luminosity can be well produced by line force driven winds model. We also find that the properties of the ultra-fast winds observed in soft X-ray bands can be explained by the line force driven winds model.
On the environmental influence of groups and clusters of galaxies beyond the virial radius: Galactic conformity at few Mpc scales
Authors: Lacerna Ivan , Rodriguez Facundo , Montero-Dorta Antonio D , O’Mill Ana L , Cora Sofía A , Artale M Celeste , Ruiz Andrés N , Hough Tomás , Vega-Martínez Cristian A
Published: April 2022

The environment within dark matter haloes can quench the star formation of galaxies. However, environmental effects beyond the virial radius of haloes (≳1 Mpc) are less evident. An example is the debated correlation between colour or star formation in central galaxies and neighbour galaxies in adjacent haloes at large separations of several Mpc, referred to as two-halo galactic conformity. We use two galaxy catalogues generated from different versions of the semi-analytic model sag applied to the mdpl2 cosmological simulation and the IllustrisTNG300 cosmological hydrodynamical simulation to study the two-halo conformity by measuring the quenched fraction of neighbouring galaxies as a function of the real-space distance from central galaxies. We find that low-mass central galaxies in the vicinity of massive systems (M200c ≥ 1013$h^{-1}~\rm M_{\odot }$) out to 5 $h^{-1}~\rm Mpc$ are preferentially quenched compared to other central galaxies at fixed stellar mass M⋆ or fixed host halo mass M200c at z ∼ 0. In all the galaxy catalogues is consistent that the low-mass (M⋆ < 1010$h^{-1}~\rm M_{\odot }$ or M200c < 1011.8$h^{-1}~\rm M_{\odot }$) central galaxies in the vicinity of clusters and, especially, groups of galaxies mostly produce the two-halo galactic conformity. On average, the quenched low-mass central galaxies are much closer to massive haloes than star-forming central galaxies of the same mass (by a factor of ∼ 5). Our results agree with other works regarding the environmental influence of massive haloes that can extend beyond the virial radius and affect nearby low-mass central galaxies.
Dusty circumbinary discs: inner cavity structures and stopping locations of migrating planets
Authors: Coleman Gavin A L , Nelson Richard P , Triaud Amaury H M J
Published: April 2022

We present the results of two-fluid hydrodynamical simulations of circumbinary discs consisting of gas and dust, with and without embedded planets, to examine the influence of the dust on the structure of the tidally truncated inner cavity and on the parking locations of migrating planets. In this proof-of-concept study, we consider Kepler-16 and Kepler-34 analogues, and examine dust fluids with Stokes numbers in the range 10−4 ≤ St ≤ 10−1 and dust-to-gas ratios of 0.01 and 1. For the canonical dust-to-gas ratio of 0.01, we find the inclusion of the dust has only a minor effect on the cavity and stopping locations of embedded planets compared to dust-free simulations. However, for the enhanced dust-to-gas ratio of unity, assumed to arise because of significant dust drift and accumulation, we find that the dust can have a dramatic effect by shrinking and circularizing the inner cavity, which brings the parking locations of planets closer to the central binary. This work demonstrates the importance of considering both gas and dust in studies of circumbinary discs and planets, and provides a potential means of explaining the orbital properties of circumbinary planets such as Kepler-34b, which have hitherto been difficult to explain using gas-only hydrodynamical simulations.
The northern cross fast radio burst project – II. Monitoring of repeating FRB 20180916B, 20181030A, 20200120E, and 20201124A
Authors: Trudu M , Pilia M , Bernardi G , Addis A , Bianchi G , Magro A , Naldi G , Pelliciari D , Pupillo G , Setti G , Bortolotti C , Casentini C , Dallacasa D , Gajjar V , Locatelli N , Lulli R , Maccaferri G , Mattana A , Michilli D , Perini F , Possenti A , Roma M , Schiaffino M , Tavani M , Verrecchia F
Published: April 2022

In this work, we report the results of a 19-month fast radio burst observational campaign carried out with the north–south arm of the Medicina Northern Cross radio telescope at 408 MHz in which we monitored four repeating sources: FRB20180916B, FRB20181030A, FRB20200120E, and FRB20201124A. We present the current state of the instrument and the detection and characterization of three bursts from FRB20180916B. Given our observing time, our detections are consistent with the event number we expect from the known burst rate (2.7 ± 1.9 above our 10σ, 38 Jy ms detection threshold) in the 5.2 d active window of the source, further confirming the source periodicity. We detect no bursts from the other sources. We turn this result into a 95 per cent confidence level lower limit on the slope of the differential fluence distribution α to be α > 2.1 and α > 2.2 for FRB20181030A and FRB20200120E, respectively. Given the known rate for FRB20201124A, we expect 1.0 ± 1.1 bursts from our campaign, consistent with our non-detection.
Using AGN light curves to map accretion disc temperature fluctuations
Authors: Neustadt J M M , Kochanek C S
Published: April 2022

We introduce a new model for understanding AGN continuum variability. We start from a Shakura–Sunyaev thin accretion disc with a steady-state radial temperature profile T(R) and assume that the variable flux is due to axisymmetric temperature perturbations δT(R, t). After linearizing the equations, we fit UV–optical AGN light curves to determine δT(R, t) for a sample of seven AGNs. We see a diversity of |δT/T| ∼ 0.1 fluctuation patterns which are not dominated by outgoing waves travelling at the speed of light as expected for the ‘lamppost’ model used to interpret disc reverberation mapping studies. Rather, the most common pattern resembles slow (v ≪ c) ingoing waves. An explanation for our findings is that these ingoing waves trigger central temperature fluctuations that act as a lamppost, producing lower amplitude temperature fluctuations moving outwards at the speed of light. The light curves are dominated by the lamppost signal – even though the temperature fluctuations are dominated by other structures with similar variability time-scales – because the discs exponentially smooth the contributions from the slower moving (v ≪ c) fluctuations to the observed light curves. This leads to light curves that closely resemble the expectations for a lamppost model but with the slow variability time-scales of the ingoing waves. This also implies that longer time-scale variability signals will increasingly diverge from lamppost models because the smoothing of slower moving waves steadily decreases as their period or spatial wavelength increases.
Fundamental differences in the properties of red and blue quasars: measuring the reddening and accretion properties with X-shooter
Authors: Fawcett V A , Alexander D M , Rosario D J , Klindt L , Lusso E , Morabito L K , Calistro Rivera G
Published: April 2022

We have recently found fundamental differences in the radio properties of red quasars when compared to typical blue quasars. In this paper, we use data from the X-shooter spectrograph on the Very Large Telescope, providing spectral coverage from ∼3000–$25\,000\,$ Å, of a sample of 40 red and blue luminous quasars at 1.45 < z < 1.65 to explore the connections between the radio, emission-line, and accretion-disc properties. We fit various dust-extinction curves to the data and find that dust reddening can fully explain the observed colours for the majority of the red quasars in our sample, with moderate extinctions ranging from AV ∼ 0.06–0.7 mag. We confront our spectra with a simple thin accretion-disc model and find this can describe the continua of both the blue and red quasars, once corrected for dust extinction; we also find no significant differences in the accretion properties. We detect ionized outflows in a number of red and blue quasars, but do not find any significant evidence that they are more prevalent in the red quasar population. Overall our findings imply that the radio emission is more closely connected to circumnuclear/ISM opacity rather than accretion disc or outflow differences.
Machine learning for fast transients for the Deeper, Wider, Faster programme with the Removal Of BOgus Transients (ROBOT) pipeline
Authors: Goode Simon , Cooke Jeff , Zhang Jielai , Mahabal Ashish , Webb Sara , Hegarty Sarah
Published: April 2022

The Deeper, Wider, Faster (DWF) programme is optimized to detect fast transients that show luminosity changes on time-scales of sub-second to days using fast cadence simultaneous observations and rapid response follow up. One of the significant bottlenecks in DWF is the time required to assess candidates for rapid follow up and to manually inspect candidates prior to triggering space-based or large ground-based telescopes. In this paper, we present the Removal Of BOgus Transients (ROBOTs) pipeline that uses a combination of machine learning methods, a Convolutional Neural Network (CNN), and Decision Tree (CART), to analyse source quality and to filter in promising candidates. The ROBOT pipeline is optimized for ‘lossy’ compressed data required by DWF for fast data transfer to find these candidates within minutes of the light hitting the telescopes. Preliminary testing of the ROBOT pipeline on archival data showed to reduce the number of candidates that require a manual inspection from 69 628 to 3327 (a factor of ∼21 times), whilst simultaneously sorting candidates into categories of priority, with potential for further improvement. Recent real-time operation of the ROBOT pipeline in DWF-O10 showed to further reduce manual inspections from ∼155 000 to ∼5000 (a factor of ∼31 times).
High-density disc reflection spectroscopy of low-mass active galactic nuclei
Authors: Mallick L , Fabian A C , García J A , Tomsick J A , Parker M L , Dauser T , Wilkins D R , De Marco B , Steiner J F , Connors R M T , Mastroserio G , Markowitz A G , Pinto C , Alston W N , Lohfink A M , Gandhi P
Published: April 2022

The standard alpha-disc model predicts an anticorrelation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass (MBH > 106 M⊙) active galactic nuclei (AGNs). In this work, we test the predictions of the alpha-disc model and study the properties of the inner accretion flow for the low-mass end (MBH ≈ 105–6 M⊙) of AGNs. We utilize a new high-density disc reflection model where the density parameter varies from ne = 1015 to 1020 cm−3 and apply it to the broad-band X-ray (0.3–10 keV) spectra of the low-mass AGN sample. The sources span a wide range of Eddington fractions and are consistent with being sub-Eddington or near-Eddington. The X-ray spectra reveal a soft X-ray excess below ∼1.5 keV which is well modelled by high-density reflection from an ionized accretion disc of density ne ∼ 1018 cm−3 on average. The results suggest a radiation pressure-dominated disc with an average of 70 per cent fraction of the disc power transferred to the corona, consistent with that observed in higher mass AGNs. We show that the disc density higher than 1015 cm−3 can result from the radiation pressure compression when the disc surface does not hold a strong magnetic pressure gradient. We find tentative evidence for a drop in black hole spin at low-mass regimes.
Mitochondrial 1555 G>A variant as a potential risk factor for childhood glioblastoma
Authors: Li Shaobo , Gai Xiaowu , Myint Swe Swe , Arroyo Katti , Morimoto Libby , Metayer Catherine , de Smith Adam J , Walsh Kyle M , Wiemels Joseph L
Published: April 2022

Background

Childhood glioblastoma multiforme (GBM) is a highly aggressive disease with low survival, and its etiology, especially concerning germline genetic risk, is poorly understood. Mitochondria play a key role in putative tumorigenic processes relating to cellular oxidative metabolism, and mitochondrial DNA variants were not previously assessed for association with pediatric brain tumor risk.

Methods

We conducted an analysis of 675 mitochondrial DNA variants in 90 childhood GBM cases and 2789 controls to identify enrichment of mitochondrial variant associated with GBM risk. We also performed this analysis for other glioma subtypes including pilocytic astrocytoma. Nuclear-encoded mitochondrial gene variants were also analyzed.

Results

We identified m1555 A>G was significantly associated with GBM risk (adjusted OR 29.30, 95% CI 5.25–163.4, P-value 9.5 X 10–4). No association was detected for other subtypes. Haplotype analysis further supported the independent risk contributed by m1555 G>A, instead of a haplogroup joint effect. Nuclear-encoded mitochondrial gene variants identified significant associations in European (rs62036057 in WWOX, adjusted OR = 2.99, 95% CI 1.88–4.75, P-value = 3.42 X 10–6) and Hispanic (rs111709726 in EFHD1, adjusted OR = 3.57, 95% CI 1.99–6.40, P-value = 1.41 X 10–6) populations in ethnicity-stratified analyses.

Conclusion

We report for the first time a potential role played by a functional mitochondrial ribosomal RNA variant in childhood GBM risk, and a potential role for both mitochondrial and nuclear-mitochondrial DNA polymorphisms in GBM tumorigenesis. These data implicate cellular oxidative metabolic capacity as a contributor to the etiology of pediatric glioblastoma.
Synthetic extracellular matrices and astrocytes provide a supportive microenvironment for the cultivation and investigation of primary pediatric gliomas
Authors: Rota Christopher M , Brown Alexander T , Addleson Emily , Ives Clara , Trumper Ella , Pelton Kristine , Teh Wei Pin , Schniederjan Matthew J , Castellino Robert Craig , Buhrlage Sara , Lauffenburger Douglas A , Ligon Keith L , Griffith Linda G , Segal Rosalind A
Published: April 2022

Background

Pediatric gliomas comprise a diverse set of brain tumor entities that have substantial long-term ramifications for patient survival and quality of life. However, the study of these tumors is currently limited due to a lack of authentic models. Additionally, many aspects of pediatric brain tumor biology, such as tumor cell invasiveness, have been difficult to study with currently available tools. To address these issues, we developed a synthetic extracellular matrix (sECM)-based culture system to grow and study primary pediatric brain tumor cells.

Methods

We developed a brain-like sECM material as a supportive scaffold for the culture of primary, patient-derived pediatric glioma cells and established patient-derived cell lines. Primary juvenile brainstem-derived murine astrocytes were used as a feeder layer to support the growth of primary human tumor cells.

Results

We found that our culture system facilitated the proliferation of various primary pediatric brain tumors, including low-grade gliomas, and enabled ex vivo testing of investigational therapeutics. Additionally, we found that tuning this sECM material allowed us to assess high-grade pediatric glioma cell invasion and evaluate therapeutic interventions targeting invasive behavior.

Conclusion

Our sECM culture platform provides a multipurpose tool for pediatric brain tumor researchers that enables both a wide breadth of biological assays and the cultivation of diverse tumor types.
Phase II study of intravenous etoposide in patients with relapsed ependymoma (CNS 2001 04)
Authors: Apps John R , Maycock Shanna , Ellison David W , Jaspan Timothy , Ritzmann Timothy A , Macarthur Donald , Mallucci Conor , Wheatley Keith , Veal Gareth J , Grundy Richard G , Picton Susan
Published: April 2022

Background

Relapsed ependymoma has a dismal prognosis, and the role of chemotherapy at relapse remains unclear. This study prospectively evaluated the efficacy of intensive intravenous (IV) etoposide in patients less than 21 years of age with relapsed intracranial ependymoma (NCT00278252).

Methods

This was a single-arm, open-label, phase II trial using Gehan’s two-stage design. Patients received IV etoposide 100 mg/m2 on days 1-3, 8-10, and 15-17 of each 28-day cycle, up to maximum of 6 cycles. Primary outcome was radiological response after 3 cycles. Pharmacokinetic analysis was performed in 10 patients.

Results

Twenty-five patients were enrolled and included in the intention-to-treat (ITT) analysis. Three patients were excluded in per-protocol (PP) analysis. After 3 cycles of etoposide, 5 patients (ITT 20%/PP 23%) had a complete response (CR), partial response (PR), or objective response (OR). Nine patients (ITT 36%/PP 41%,) had a best overall response of CR, PR, or OR. 1-year PFS was 24% in ITT and 23% in PP populations. 1-year OS was 56% and 59%, 5-year OS was 20% and 18%, respectively, in ITT and PP populations. Toxicity was predominantly hematological, with 20/25 patients experiencing a grade 3 or higher hematological adverse event.

Conclusions

This study confirms the activity of IV etoposide against relapsed ependymoma, however, this is modest, not sustained, and similar to that with oral etoposide, albeit with increased toxicity. These results confirm the dismal prognosis of this disease, provide a rationale to include etoposide within drug combinations, and highlight the need to develop novel treatments for recurrent ependymoma.
The allosteric gating mechanism of the MthK channel
Authors: Guan Fenghui , Li Tianyu , Dong Wei , Guo Rui , Chai Hao , Chen Zhiqiu , Ren Zhong , Li Yang , Ye Sheng
Published: April 2022

Allostery is a fundamental element during channel gating in response to an appropriate stimulus by which events occurring at one site are transmitted to distal sites to regulate activity. To address how binding of the first Ca2+ ion at one of the eight chemically identical subunits facilitates the other Ca2+-binding events in MthK, a Ca2+-gated K+ channel containing a conserved ligand-binding RCK domain, we analysed a large collection of MthK structures and performed the corresponding thermodynamic and electrophysiological measurements. These structural and functional studies led us to conclude that the conformations of the Ca2+-binding sites alternate between two quaternary states and exhibit significant differences in Ca2+ affinity. We further propose an allosteric model of the MthK-gating mechanism by which a cascade of structural events connect the initial Ca2+-binding to the final changes of the ring structure that open the ion-conduction pore. This mechanical model reveals the exquisite design that achieves the allosteric gating and could be of general relevance for the action of other ligand-gated ion channels containing the RCK domain.
A Content Analysis of Promotional Features in US Direct-Mail From Advertisements Across Tobacco Products From 2018 to 2020
Authors: Silver Nathan , Rahman Basmah , Folger Shanell , Bertrand Adrian , Khatib Bushraa , Gbenro Macred , Schillo Barbara
Published: April 2022

Introduction

Direct-mail advertising is a crucial channel through which tobacco companies deliver price incentives that lower the barrier to tobacco use while promoting tobacco products via thematic appeals not legally permitted on other marketing channels. We examine the prevalence of price incentives and ad characteristics used in tobacco product advertisements (ads) mailed directly to US consumers.

Aims and Methods

We analyzed the content of direct-mail tobacco ads (N = 1047) in circulation between January 2018 and December 2020 as captured by Mintel Comperemedia Direct. These ads were coded for product type, manufacturer/brand type, model characteristics, price incentives, and themes known to appeal to vulnerable subgroups.

Results

Ads across all tobacco products included price incentives (96%) and contained themes that appealed to rural white (40%) and black audiences (15%). Themes known to appeal to youth and young adults were present in 40% of ads across all products, including 78% of ads promoting electronic nicotine delivery systems (ENDS). Moreover, the ENDS ads featuring youth appealing themes (51%), also featured young models.

Discussion

Expanding on previous research which focused on combustible and smokeless tobacco products, this analysis examines direct-mail ads across the full range of tobacco products. Our findings highlight the need for regulations to address (1) the high prevalence of price incentives that undermine the effectiveness of excise taxes on tobacco use, and (2) ad themes and characteristics that appeal to groups vulnerable to tobacco use, both of which have the potential to further exacerbate tobacco-related health disparities.

Implications

This study reinforces the importance of examining direct-mail as the dominant medium for tobacco advertising, particularly by including coupons and discount codes that reduce product price and thus circumventing the effect of tobacco-related tax legislation. Direct-mail encourages continued product loyalty and use and engages new consumers using price incentives and advertising strategies likely to appeal to price-sensitive consumers and other vulnerable populations. Substantial use of youth-appealing elements in ENDS ads contradicts the tobacco industry’s mandate to not appeal to youth, warranting highlighting the gaps in current regulations that allows them to continue appealing to this population.
The Consequences of the Coronavirus Disease 2019 Pandemic on Smoking Behavior: Evidence from the English Longitudinal Study of Ageing
Authors: Gaggero Alessio
Published: April 2022

Introduction

Smoking is a risk factor for the progression of COVID-19, with smokers having higher odds of COVID-19 progression than never-smokers. This study presents novel findings on the effect of the COVID-19 pandemic on smoking behavior in older adults.

Methods

Panel data were obtained from the English Longitudinal Study of Ageing (N = 60160, 12% smokers, 55% women, 62% married, mean age = 67 years, 23% employed). Fixed-effect regression models were used to estimate the extent to which the COVID-19 pandemic affected smoking behavior. A separate model was estimated for men, women, employed, and retired.

Results

The findings suggest a significant and positive effect of the COVID-19 pandemic on smoking behavior (β = 0.024; P < .001). The estimated effects were stronger for men and for the sample of individuals reporting being employed.

Conclusions

In this study, I provide robust evidence of the effect of the COVID-19 pandemic on smoking behavior using the English Longitudinal Study of Ageing. This large and representative dataset is uniquely suited for the analysis. I find evidence that the proportion of smokers has increased significantly as a result of the COVID-19 pandemic.

Implications

In the United Kingdom, the proportion of smokers increased significantly as a consequence of the COVID-19 pandemic. These findings suggest that smoking behavior may have been used as a mechanism to cope with depression, stress, and anxiety due to the COVID-19 outbreak. To the extent to which smoking behavior has been used as a coping mechanism to deal with job-related issues, targeted policy action to provide financial stability to those in worse economic situations may have beneficial effects on smoking behavior.
Net economic benefits of well-below 2°C scenarios and associated uncertainties
Authors: Drouet Laurent , Bosetti Valentina , Tavoni Massimo
Published: April 2022

Climate stabilization pathways reviewed by the Intergovernmental Panel on Climate Change depict the transformation challenges and opportunities of a low carbon world. The scenarios provide information about the transition, including its economic repercussions. However, these calculations do not account for the economic benefits of lowering global temperature; thus, only gross policy costs are reported and discussed. Here, we show how to combine low carbon pathways’ mitigation costs with the growing but complex literature quantifying the economic damages of climate change. We apply the framework to the scenarios reviewed in the Special Report on 1.5°C of the Intergovernmental Panel on Climate Change. Under a probabilistic damage function and climate uncertainty, we show that Paris-compliant trajectories have net present economic benefits but are not statistically different from zero. After mid-century, most scenarios have higher benefits than costs; these net benefits are most prominent in developing countries. We explore the robustness of results to an extensive set of damage functions published in the literature, and for most of the specifications examined, we cannot reject the null hypothesis of net benefits. Future research could improve these results with a better understanding of damage functions with greater coverage of damages and including adaptation and its cost.
Indigenous Knowledge and Oral Traditions in Nigeria
Authors: Falola Toyin
Published: April 2022

Historical reconstruction and documentation of events and practices among preliterate societies is a dauting task with which Africanist scholars—historians in particular—must contend. In the face of growing concern about the accuracy of the information produced regarding the African past and preserved in the colonial archives, oral traditions, in their various forms, have gained more traction among Africanist scholars. These traditions consist of several genres of indigenous knowledge production communicated to us verbally through what has been described as “ritual archives,” “oral artifacts,” and many more, as they constitute the pillars of African past and personality. Over the years, these traditions have evolved along with the cultures and societies that produced them. This chapter interrogates the viability of these sources vis-à-vis their meanings, makings, limitations, and changes in practice and theory as related to the Nigerian experience.
Nigeria and African Affairs
Authors: Oyebade Adebayo
Published: April 2022

This chapter examines Nigeria’s role in African affairs from its independence in 1960 to the present time. It introduces readers to the dynamics of the country’s foreign policy toward Africa and relations with some African states. It reviews the Nigerian foreign policy shift from the cautious, conservative preoccupation of the 1960s to the bolder, more radical principles of the post-civil war period in the 1970s and 1980s. It examines Nigeria as a dominant power on the continent for much of its post-independence history, its role in West Africa’s subregion, and within the pan-African body, the Organization of African Unity (now African Union). Further, it examines Nigeria’s role in Africa’s struggle against European imperialism, especially its leadership of the liberation movement in Southern Africa. Finally, the chapter briefly examines Nigeria’s declining power in Africa in the contemporary period.
State Management and Political Institutions in Nigeria before 1800
Authors: Osadolor Osarhieme Benson
Published: April 2022

The evolution of political institutions before 1800 derived from the origins of social complexity, and the responses to local geographical factors, not least of which were contacts with other cultures or their influences that stimulated the emergence of a wide range of diverse power structures and socio-political superstructures for state management. The wielding of authority and the function of governing was closely related to the emergence of the state, its management, and political institutions’ evolution. The wide variety of state structures is also derived from the many trajectories of state formation. The mega- and mini-states’ political structures reflect diverse power structures, authority, and organizational structures. The most common of the politically organized community was the kingdom, which was a territorial unit with a kingship system, though Great Benin Empire, Oyo Empire, and Kanem–Borno Empire engaged in empire-building to enlarge the size of their territories and the influence of their power and authority in a wider geographical area.
The Conquest of Nigeria
Authors: Sani Abubakar Babajo
Published: April 2022

This chapter relates the British colonial conquest of Nigeria, which began with the removal of all visible oppositions to the imposition of British rule. It talks about the expansion and consolidation of British rule, and the use of diplomacy and coercion to reduce and contain potential opposition. It also mentions inaccessible areas in Northern Nigeria that offered pockets of stiff resistance to the British until the 1920s, located in some remote places with rough topography and decentralized political systems. The chapter looks at the series of events that occurred in Nigerian regions between 1885 and 1914 that have their roots in Europe since the early nineteenth century and were linked to Industrialization and the rise of New Imperialism. It highlights the colonial occupation of the Nigerian areas, the process of the occupation, and how Nigeria was incorporated under the British colonial empire.
Agriculture, Environment, and Sustainable Development in Nigeria
Authors: Korieh Chima J.
Published: April 2022

Agriculture is the most critical economic activity in every society. It has historically remained the source of food that sustains the population and a source of wealth accumulation. This chapter looks at the intersection of environment, agriculture, and sustainable development. Whether it be crop production or animal husbandry, suitable agricultural production is dependent on a suitable and sustainable environment. This article looks at the link between the environment, agricultural productivity, and sustainable development. It also examines the link between contemporary agricultural crisis and environmental crisis and how both issues have posed a challenge to continued and future suitable, sustainable development.
Embrainment and Enculturation: Culture, Brain, and Self
Authors: Northoff Georg
Published: April 2022

Embrainment and enculturation are central concepts in cultural neuroscience, but their mechanisms remain unclear. Embrainment describes how cultural contexts are encoded into the brain’s neuronal activity, whereas enculturation means that neuronal activity is impacted by cultural contexts as manifested in the brain’s affective and cognitive functions. This chapter takes the self as a paradigmatic example of embrainment and enculturation. It discusses different concepts of self and shows the neuronal correlates of self, which highlight spatiotemporal, scale-free (i.e., across different spatial and temporal scales operating in a self-similar way), and stochastic mechanisms. That very same spatiotemporal, scale-free, and stochastic encoding is manifested on the mental level in human selves, which, therefore, are relational and spatiotemporal. The chapter concludes that embrainment and enculturation reflect two distinct aspects of one and the same underlying process, that is, self-related processing as manifested in the self as relational self. Moreover, as human selves provide the basis of mental health, the here-described mechanisms of embrainment and enculturation of self are central for global mental health as people with their self and the underlying brain’s spontaneous activity move across different cultures.
String Instruments—Bowed
Authors: Woodhouse Jim
Published: April 2022

This chapter provides an introduction to the scientific study of bowed-string instruments, concentrating on aspects that are of direct relevance to performers. Points of similarity and contrast with plucked-string instruments are discussed. A key similarity is in the question of what governs the loudness of any acoustical string instrument. The key contrast is in the manner in which a bowed string vibrates: this is governed by more complicated physics than the vibration of a plucked string, and this has important implications for “playability” and other aspects of performance such as the wolf note. Because of the nature of the subject matter, the organization of the chapter does not separate the background science from the implications for performance: as each successive topic is discussed, implications for performers and teachers are discussed in an integrated way.
Motion Capture of Music Performances
Authors: Wanderley Marcelo M.
Published: April 2022

Motion capture (mocap)—the recording of three-dimensional movement using high-accuracy systems—has become a standard research tool in the analysis of music performances in the last two decades. A variety of systems is currently available, ranging from optical, multi-camera (passive and/or active) infra-red systems and inertial systems (using orientation sensors) to electromagnetic trackers providing six degrees-of-freedom (DoF) measurement per marker/sensor. Recent advances in technology have made many of these systems more affordable, allowing access to a large research community. Music-related mocap applications include the tracking movements of solo or group, beginner, or expert performers and instruments for teaching performance skills, comparing movement strategies across performers, generating movement synthesis parameters in animation, and use in real-time music interaction. This chapter introduces the basic concepts behind motion capture, reviews the most common mocap technologies used in the study of music performance, and presents several examples of research, pedagogy, and artistic uses. Mocap of single acoustic instrument performances is reviewed, including violin, cello, piano, clarinet, timpani, and acoustic guitar, as well as examples of mocap of multiple instruments. Finally, we discuss the limitations of mocap and possible solutions to overcome them.