bluuebunny/crossref_metadata_2025 huggingface dataset:
Permafrost Hydrogeology of Taylor Valley, Antarctica: Insights From Deep Electrical Resistivity Tomography
Authors: Romano Valentina , Fischanger Federico , Wilson Gary , Sciarra Alessandra , Mazzini Adriano , Mazzoli Claudio , Florindo Fabio , Tartarello Maria Chiara , Ascani Massimiliano , Anderson Jacob , Worthington Rachel , Hardie Richard , Dagg Bob , Ruggiero Livio
Published: September 2024

Global warming has prompted globally widespread permafrost thawing, resulting in enhanced greenhouse gas release into the atmosphere. Studies conducted in the Northern Hemisphere reveal an alarming increase in permafrost thawing. However, similar data from Antarctica are scarce. We conducted a 2‐D Deep Electrical Resistivity Tomography (DERT) survey in Taylor Valley, Antarctica, to image the distribution of permafrost, its thicknesses, lower boundaries, and hydrogeology. Results show resistive, discontinuous domains that we suggest represent permafrost units. We also find highly conductive layers (5–10 Ω·m), between 300–350 m and 600–650 m below ground level and a shallower (∼50–100 m depth) conductive layer. The combined data set reveals a broad brine system in Taylor Valley, implying multi‐tiered groundwater circulation: a shallow, localized system linked with surface water bodies and a separate deeper, regional circulation system. The arrangement of these brines across different levels, coupled with the uneven permafrost distribution, underscores potential interplay between the two systems.
A Simple Model of Flow Reversals in Florida’s Karst Springs
Authors: Klammler Harald , Jawitz James W. , Cohen Matthew J.
Published: September 2024

North Florida's karst springs are among the largest and most abundant in the world. Despite relatively stable spring discharges, flow reversals can episodically occur in some springs when river waters backflow into the aquifer during flood events. Reversals are normal features of the springs along the Suwanee River, but the changing incidence of these reversals in response to anthropogenic activities or climate change remains unclear and the mechanisms responsible for these reversals remain poorly described. Here we develop a reduced‐complexity hydrogeological model of the Suwannee River catchment to explore conditions needed to induce spring flow reversals. Our model demonstrates that reversals require two conditions: (a) a hydrogeological setting that combines an upstream catchment with rapid hydrological responses to meteorological drivers, which freely drains to a downstream catchment containing the karst aquifer (i.e., the spring‐fed river segment); and (b) meteorological conditions that create sufficient temporal variability in recharge. Given both conditions, recharge events can propagate from the upstream catchment and fill the downstream river segment faster than it can drain, causing river stage to rise above the aquifer head, resulting in temporary spring flow reversal (or bank storage). Our model accurately predicts significant post‐flood increases in spring flow as bank storage recedes, and using measured electrical conductivity at a major river‐adjacent spring we also quantify the enhancement of limestone dissolution (cave enlargement) due to reversal events. A comprehensive assessment of the incidence and duration of reversal events shows a predominant influence of climate and vegetation changes over that of groundwater pumping.
Estimating Grain Sizes of Martian Dune Sand: A Freeware‐Based Methodology With Initial Results
Authors: Burr D. M. , Nguyen V. N. H. , Gibson T. M.‐G. , Chinchkhede T.
Published: September 2024

Grain sizes of Martian sand dunes are critical sedimentological data on sand provenance and transport pathways. Thermal inertia values are used to characterize the grain sizes of dune sand. Most early characterizations involved single dune fields. Recent work based on global data sets has provided more wide‐spread dune sand locations, though these data sets include the non‐sandy interdune areas. To provide a more accurate grain size characterization, we leverage a global thermal inertia data set, a global dune database and a global imaging mosaic to develop a freeware‐based methodology for deriving grain sizes. This methodology involves delineation of sand‐only areas within dune fields and collection of thermal inertia values from those areas. We consider a unimodal histogram of values with a mode <∼350 thermal inertia units (J m−2 K−1 s−1/2) to imply an effective exclusion of non‐sand surfaces. Application of this methodology to dune fields for which thermal inertia values have been previous derived shows our results fall within the envelope of those values. We apply our methodology to tropical dune fields on Mars for which Dust Cover Index data imply dust‐free surfaces. Conversion of these thermal inertia values to sand grain sizes yields a range of sand classifications of fine sand to granules. Comparison of sand size classifications with geographic location shows grain size ranges that are distinctive by location, consistent with local sourcing. This work points toward geographically diverse sand formation mechanisms yielding diverse grain sizes, while providing a freeware‐based and thus widely accessible method for expanding the derivation of these critical data.
Particle Simulation Study of Obliquely Propagating Whistler Waves in Low‐Beta Plasmas
Authors: Wu Yifan , Zhao Jinsong , Tao Xin , Dai Lei
Published: September 2024

Whistler mode waves, which are electromagnetic emissions commonly observed in various space plasma environments, play critical roles in electron dynamics. While most whistler waves are driven by temperature anisotropy and propagate parallel to the background magnetic field, these waves can also be excited in the oblique direction when electron plasma beta is very low (<0.025). Although linear theory accounts for the excitation processes of obliquely propagating whistler waves, the subsequent evolution and saturation processes remain inadequately understood. This study utilizes two‐dimensional self‐consistent simulations to investigate the complete wave‐particle interaction process. By scanning a broad parameter range, we derive scaling laws for the wave intensity, linking the wave properties to initial and final plasma conditions. The saturated temperature anisotropy from simulations can explain the upper bound anisotropy constraint observed by spacecraft well. Additional phase space analysis shows that both Landau and cyclotron resonance play critical roles in the evolution of electron velocity distribution, albeit in different energy ranges. Oblique whistler waves can effectively heat electrons through Landau resonance, creating a plateau distribution in the parallel direction. This research advances our understanding of the mechanisms behind obliquely propagating whistler waves in low‐beta plasmas and their impact on electron dynamics.
Fundamental equations linking methylation dynamics to maximum lifespan in mammals
Authors: Horvath Steve , Zhang Joshua , Haghani Amin , Lu Ake T. , Fei Zhe
Published: September 2024

We describe a framework that addresses concern that the rate of change in any aging biomarker displays a trivial inverse relation with maximum lifespan. We apply this framework to methylation data from the Mammalian Methylation Consortium. We study the relationship of lifespan with the average rate of change in methylation (AROCM) from two datasets: one with 90 dog breeds and the other with 125 mammalian species. After examining 54 chromatin states, we conclude three key findings: First, a reciprocal relationship exists between the AROCM in bivalent promoter regions and maximum mammalian lifespan: AROCM $$\propto$$
∝
1/MaxLifespan. Second, the correlation between average methylation and age bears no relation to maximum lifespan, Cor(Methyl,Age) ⊥ MaxLifespan. Third, the rate of methylation change in young animals is related to that in old animals: Young animals’ AROCM $$\propto$$
∝
Old AROCM. These findings critically hinge on the chromatin context, as different results emerge in other chromatin contexts.
Regional patterns of human cortex development correlate with underlying neurobiology
Authors: Lotter Leon D. , Saberi Amin , Hansen Justine Y. , Misic Bratislav , Paquola Casey , Barker Gareth J. , Bokde Arun L. W. , Desrivières Sylvane , Flor Herta , Grigis Antoine , Garavan Hugh , Gowland Penny , Heinz Andreas , Brühl Rüdiger , Martinot Jean-Luc , Paillère Marie-Laure , Artiges Eric , Papadopoulos Orfanos Dimitri , Paus Tomáš , Poustka Luise , Hohmann Sarah , Fröhner Juliane H. , Smolka Michael N. , Vaidya Nilakshi , Walter Henrik , Whelan Robert , Schumann Gunter ,   IMAGEN Consortium, Nees Frauke , Banaschewski Tobias , Eickhoff Simon B. , Dukart Juergen
Published: September 2024

Human brain morphology undergoes complex changes over the lifespan. Despite recent progress in tracking brain development via normative models, current knowledge of underlying biological mechanisms is highly limited. We demonstrate that human cortical thickness development and aging trajectories unfold along patterns of molecular and cellular brain organization, traceable from population-level to individual developmental trajectories. During childhood and adolescence, cortex-wide spatial distributions of dopaminergic receptors, inhibitory neurons, glial cell populations, and brain-metabolic features explain up to 50% of the variance associated with a lifespan model of regional cortical thickness trajectories. In contrast, modeled cortical thickness change patterns during adulthood are best explained by cholinergic and glutamatergic neurotransmitter receptor and transporter distributions. These relationships are supported by developmental gene expression trajectories and translate to individual longitudinal data from over 8000 adolescents, explaining up to 59% of developmental change at cohort- and 18% at single-subject level. Integrating neurobiological brain atlases with normative modeling and population neuroimaging provides a biologically meaningful path to understand brain development and aging in living humans.
Underestimation of personal carbon footprint inequality in four diverse countries
Authors: Nielsen Kristian S. , Bauer Jan M. , Debnath Ramit , Emogor Charles A. , Geiger Sonja M. , Ghai Sakshi , Gwozdz Wencke , Hahnel Ulf J. J.
Published: September 2024

Extensive research highlights global and within-country inequality in personal carbon footprints. However, the extent to which people are aware of these inequalities remains unclear. Here we use an online survey distributed across four diverse countries: Denmark, India, Nigeria and the USA, to show widespread underestimation of carbon footprint inequality, irrespective of participants’ country and income segment. Of the 4,003 participants, within each country, 50% of participants were sampled from the top 10% income group. Our results show links between carbon footprint inequality perceptions and climate policy support, but with significant variations observed across the four countries and with participants’ income segments. Furthermore, there are links to the perceived fairness of actual carbon footprint inequality, highlighting the need to raise awareness about carbon footprint inequality and further unpack its implications for climate justice and policy.
Acidity suppresses CD8 + T-cell function by perturbing IL-2, mTORC1, and c-Myc signaling
Authors: Vuillefroy de Silly Romain , Pericou Laetitia , Seijo Bili , Crespo Isaac , Irving Melita
Published: September 2024

CD8 + T cells have critical roles in tumor control, but a range of factors in their microenvironment such as low pH can suppress their function. Here, we demonstrate that acidity restricts T-cell expansion mainly through impairing IL-2 responsiveness, lowers cytokine secretion upon re-activation, and reduces the cytolytic capacity of CD8 + T cells expressing low-affinity TCR. We further find decreased mTORC1 signaling activity and c-Myc levels at low pH. Mechanistically, nuclear/cytoplasmic acidification is linked to mTORC1 suppression in a Rheb-, Akt/TSC2/PRAS40-, GATOR1- and Lkb1/AMPK-independent manner, while c-Myc levels drop due to both decreased transcription and higher levels of proteasome-mediated degradation. In addition, lower intracellular levels of glutamine, glutamate, and aspartate, as well as elevated proline levels are observed with no apparent impact on mTORC1 signaling or c-Myc levels. Overall, we suggest that, due to the broad impact of acidity on CD8 + T cells, multiple interventions will be required to restore T-cell function unless intracellular pH is effectively controlled.
Epigenetic inheritance and gene expression regulation in early Drosophila embryos
Authors: Ciabrelli Filippo , Atinbayeva Nazerke , Pane Attilio , Iovino Nicola
Published: September 2024

Precise spatiotemporal regulation of gene expression is of paramount importance for eukaryotic development. The maternal-to-zygotic transition (MZT) during early embryogenesis in Drosophila involves the gradual replacement of maternally contributed mRNAs and proteins by zygotic gene products. The zygotic genome is transcriptionally activated during the first 3 hours of development, in a process known as “zygotic genome activation” (ZGA), by the orchestrated activities of a few pioneer factors. Their decisive role during ZGA has been characterized in detail, whereas the contribution of chromatin factors to this process has been historically overlooked. In this review, we aim to summarize the current knowledge of how chromatin regulation impacts the first stages of Drosophila embryonic development. In particular, we will address the following questions: how chromatin factors affect ZGA and transcriptional silencing, and how genome architecture promotes the integration of these processes early during development. Remarkably, certain chromatin marks can be intergenerationally inherited, and their presence in the early embryo becomes critical for the regulation of gene expression at later stages. Finally, we speculate on the possible roles of these chromatin marks as carriers of epialleles during transgenerational epigenetic inheritance (TEI).
The colonic polyphenol catabolite dihydroferulic acid (DHFA) regulates macrophages activated by oxidized LDL, 7-ketocholesterol, and LPS switching from pro- to anti-inflammatory mediators
Authors: Lara-Guzmán Oscar J. , Arango-González Ángela , Rivera Diego A. , Muñoz-Durango Katalina , Sierra Jelver A.
Published: September 2024

Macrophage activation plays a central role in the development of atherosclerotic plaques.
Rational design of NT-PSMA heterobivalent probes for prostate cancer theranostics
Authors: Previti Santo , Bodin Sacha , Rémond Emmanuelle , Vimont Delphine , Hindié Elif , Morgat Clément , Cavelier Florine
Published: September 2024

Linker and chelating agents strongly influence the binding affinity of the NTS1-PSMA heterobivalent probe towards NTS1. Comparable affinities between mono- and heterobivalent ligands towards PSMA were observed.
Synthesis of unsymmetrical 2,4-diaryl substituted and 3-bromo-2-(4-bromoalkoxy)-derived pyranocoumarins
Authors: Saravanan Velu , Lin Pin-Hui , Yang Ding-Yah
Published: September 2024

4-Arylpyranocoumarins were prepared as precursors to construct unsymmetrical 2,4-disubstituted and dibromo-derived pyranocoumarins via Heck coupling and a three-component reaction, respectively.
A synthetic method for lanthanum hydroxychloride suitable for industrialization and its thermal decomposition properties
Authors: Tian Hao , Guo Jincheng , Pei Yu , Hou Shaochun , Wang Yuanjiang , Xia Yumei
Published: September 2024

Lanthanum hydroxychloride is synthesized through a reactive crystallization method at low temperature and with a short cycle length in high yields.
Porphyrin photosensitizer molecules as effective medicine candidates for photodynamic therapy: electronic structure information aided design
Authors: Yin Wei-Huang , Li Peng-Yuan , Huang Hou-Hou , Feng Lu , Liu Shu-Hui , Liu Xin , Bai Fu-Quan
Published: September 2024

Novel porphyrin photosensitizer molecules, incorporating perylene diimide groups (PDI), were meticulously designed and screened using electronic structure calculations.
Electron diffraction and solid-state NMR reveal the structure and exciton coupling in a eumelanin precursor
Authors: Vinod Kavya , Mathew Renny , Jandl Christian , Thomas Brijith , Hariharan Mahesh
Published: September 2024

A bottom-up investigation strategy for eumelanin's structure–property relationship by a multidisciplinary approach, using 3D electron diffraction, solid-state NMR, density functional theory and electronic spectroscopy.
Osmotic spawning vesicle
Authors: Kurisu Minoru , Imai Masayuki
Published: September 2024

We discovered a novel division mechanism of vesicles. This simple and highly productive system will provide proliferation ability to existing and future microcompartment systems, simply by selecting suitable membrane compositions and osmolytes.
Self-supervised learning on MeerKAT wide-field continuum images
Authors: Lastufka E. , Bait O. , Taran O. , Drozdova M. , Kinakh V. , Piras D. , Audard M. , Dessauges-Zavadsky M. , Holotyak T. , Schaerer D. , Voloshynovskiy S.
Published: September 2024

Context. Self-supervised learning (SSL) applied to natural images has demonstrated a remarkable ability to learn meaningful, low-dimension representations without labels, resulting in models that are adaptable to many different tasks. Until now, applications of SSL to astronomical images have been limited to Galaxy Zoo datasets, which require a significant amount of preprocessing to prepare sparse images centered on a single galaxy. With wide-field survey instruments at the forefront of the Square Kilometer Array (SKA) era, this approach to gathering training data is impractical.

Aims. We demonstrate that continuum images from surveys such as the MeerKAT Galactic Cluster Legacy Survey (MGCLS) can be successfully used with SSL, without extracting single-galaxy cutouts.

Methods. Using the SSL framework DINO, we experimented with various preprocessing steps, augmentations, and architectures to determine the optimal approach for this data. We trained both ResNet50 and Vision Transformer (ViT) backbones.

Results. Our models match state-of-the-art results (trained on Radio Galaxy Zoo) for FRI/FRII morphology classification. Furthermore, they predict the number of compact sources via linear regression with much higher accuracy. Open-source foundation models trained on natural images such as DINOv2 also excel at simple FRI/FRII classification; the advantage of domain-specific backbones is much smaller models trained on far less data. Smaller models are more efficient to fine-tune, and doing so results in a similar performance between our models, the state-of-the-art, and open-source models on multi-class morphology classification.

Conclusions. Using source-rich crops from wide-field images to train multi-purpose models is an easily scalable approach that significantly reduces data preparation time. For the tasks evaluated in this work, twenty thousand crops is sufficient training data for models that produce results similar to state-of-the-art. In the future, complex tasks like source detection and characterization, together with domain-specific tasks, ought to demonstrate the true advantages of training models with radio astronomy data over natural-image foundation models.
High-resolution observations of 12CO and 13CO J = 3 → 2 towards the NGC 6334 extended filament
Authors: Neupane S. , Wyrowski F. , Menten K. M. , Urquhart J. , Colombo D. , Lin L.-H. , Garay G.
Published: September 2024

NGC 6334 is a giant molecular cloud (GMC) complex that exhibits elongated filamentary structure and harbours numerous OB-stars, H II regions, and star-forming clumps. To study the emission morphology and velocity structure of the gas in the extended NGC 6334 region using high-resolution molecular line data, we made observations of the 12CO and 13CO J = 3 → 2 lines with the LAsMA instrument at the APEX telescope. The LAsMA data provided a spatial resolution of 20″ (~0.16 pc) and sensitivity of 0.4 K at a spectral resolution of 0.25 km s−1. Our observations revealed that gas in the extended NGC 6334 region exhibits connected velocity coherent structure over ~80 pc parallel to the Galactic plane. The NGC 6334 complex has its main velocity component at approximately −3.9 km s−1 with two connected velocity structures at velocities approximately −9.2 km s−1 (the ‘bridge’ features) and −20 km s−1 (the northern filament, NGC 6334-NF). We observed local velocity fluctuations at smaller spatial scales along the filament that are likely tracing local density enhancement and infall, while the broader V-shaped velocity fluctuations observed towards the NGC 6334 central ridge and G352.1 region located in the eastern filament EF1 indicate globally collapsing gas onto the filament. We investigated the 13CO emission and velocity structure around 42 WISE H II regions located in the extended NGC 6334 region and found that most H II regions show signs of molecular gas dispersal from the centre (36 of 42) and intensity enhancement at their outer radii (34 of 42). Furthermore most H II regions (26 of 42) are associated with least one ATLASGAL clump within or just outside of their radii, the formation of which may have been triggered by H II bubble expansion. Typically towards larger H II regions we found visually clear signatures of bubble shells emanating from the filamentary structure. Overall the NGC 6334 filamentary complex exhibits sequential star formation from west to east. Located in the west, the GM-24 region exhibits bubbles within bubbles and is at a relatively evolved stage of star formation. The NGC 6334 central ridge is undergoing global gas infall and exhibits two gas bridge features possibly connected to the cloud-cloud collision scenario of the NGC 6334-NF and the NGC 6334 main gas component. The relatively quiescent eastern filament (EF1 - G352.1) is a hub-filament in formation, which shows the kinematic signature of global gas infall onto the filament. Our observations highlight the important role of H II regions in shaping the molecular gas emission and velocity structure as well as the overall evolution of the molecular filaments in the NGC 6334 complex.
The K2-24 planetary system revisited by CHEOPS
Authors: Nascimbeni V. , Borsato L. , Leonardi P. , Sousa S. G. , Wilson T. G. , Fortier A. , Heitzmann A. , Mantovan G. , Luque R. , Zingales T. , Piotto G. , Alibert Y. , Alonso R. , Bárczy T. , Barrado Navascues D. , Barros S. C. C. , Baumjohann W. , Beck T. , Benz W. , Billot N. , Biondi F. , Brandeker A. , Broeg C. , Busch M.-D. , Collier Cameron A. , Correia A. C. M. , Csizmadia Sz. , Cubillos P. E. , Davies M. B. , Deleuil M. , Deline A. , Delrez L. , Demangeon O. D. S. , Demory B.-O. , Derekas A. , Edwards B. , Ehrenreich D. , Erikson A. , Fossati L. , Fridlund M. , Gandolfi D. , Gazeas K. , Gillon M. , Güdel M. , Günther M. N. , Helling Ch. , Isaak K. G. , Kerschbaum F. , Kiss L. L. , Korth J. , Lam K. W. F. , Laskar J. , Lecavelier des Etangs A. , Leleu A. , Lendl M. , Magrin D. , Maxted P. F. L. , Merín B. , Mordasini C. , Olofsson G. , Ottensamer R. , Pagano I. , Pallé E. , Peter G. , Pollacco D. , Queloz D. , Ragazzoni R. , Rando N. , Rauer H. , Ribas I. , Santos N. C. , Scandariato G. , Ségransan D. , Simon A. E. , Smith A. M. S. , Southworth R. , Stalport M. , Sulis S. , Szabó Gy. M. , Udry S. , Ulmer B. , Van Grootel V. , Venturini J. , Villaver E. , Walton N. A.
Published: September 2024

The planetary system K2-24 is composed of two transiting low-density Neptunians locked in an almost perfect 2:1 resonance and showing large transit time variations (TTVs), and it is an excellent laboratory to search for signatures of planetary migration. Previous studies performed with K2, Spitzer, and RV data tentatively claimed a significant non-zero eccentricity for one or both planets, possibly high enough to challenge the scenario of pure disk migration through resonant capture. With 13 new CHEOPS light curves (seven of planet b, six of planet c), we carried out a global photometric and dynamical re-analysis by including all the available literature data as well. We obtained the most accurate set of planetary parameters to date for the K2-24 system, including radii and masses at 1% and 5% precision (now essentially limited by the uncertainty on stellar parameters) and non-zero eccentricities eb = 0.0498−0.0018+0.0011, ec = 0.0282−0.0007+0.0003 detected at very high significance for both planets. Such relatively large values imply the need for an additional physical mechanism of eccentricity excitation during or after the migration stage. Also, while the accuracy of the previous TTV model had drifted by up to 0.5 days at the current time, we constrained the orbital solution firmly enough to predict the forthcoming transits for the next ~15 years, thus enabling efficient follow-up with top-level facilities such as JWST or ESPRESSO.
Revisiting orogens during the OROGEN project: tectonic maturity, a key element to understand orogenic variability
Authors: Masini Emmanuel , Jammes Suzon , Calassou Sylvain , Vidal Olivier , Thinon Isabelle , Manatschal Gianreto , Chevrot Sébastien , Ford Mary , Mouthereau Frédéric , Lacombe Olivier ,   The Orogen Team
Published: September 2024

By demonstrating that extensional inheritance plays a decisive role in the formation of orogens, recent studies have questioned the ability of a unique, complete Wilson cycle model to explain the diversity of collisional orogens. For 5 years, the OROGEN Research Project had therefore the ambition to challenge this classical Wilson cycle model. By focusing on the diffuse Africa-Europe plate boundary in the Biscay-Pyrenean-Western Mediterranean system, the project questioned the preconceived “Orogen singularity” assumption and investigated the role of divergent and convergent maturities in orogenic and post-orogenic processes. This work led us to rethink the development of collisional orogens in a genetic (or process-driven) way and to propose an updated version of the ” classical Wilson cycle”, the Wilson Cycle 2.0, and the ORO-Genic ID concept presented in this paper. The particularity of the Wilson Cycle 2.0 is to take into account the divergence and convergence maturity reached during extensional and orogenic processes in proposing different tectonic tracks associated with different ORO-Genic ID numbers. The ORO-Genic ID is composed of a letter (or track), corresponding to the maturity of divergence reached and a number corresponding to the maturity of convergence reached during the formation of the orogen. This new concept relies on the observed pre- and syn- convergent tectono- stratigraphic and magmatic record and deformation history and can be identified in using diagnostic criteria presented in this paper. It represents therefore a powerful tool that can be used to characterize the evolution and the architectural type of an orogenic system. Moreover, as a mappable concept, it can be easily used worldwide and can help us to explain differences in the style of deformation at crustal scale between orogens.
Quantitative uniqueness estimates for stochastic parabolic equations on the whole Euclidean space
Authors: Liu Yuanhang , Yang Donghui , Zeng Xingwu , Zhang Can
Published: September 2024

In this paper, a quantitative estimate of unique continuation for the stochastic heat equation with bounded potentials on the whole Euclidean space is established. This paper generalizes the earlier results in [X. Zhang. Differ. Integral Equ. 21 (2008) 81–93] and [Q. Lü and Z. Yin ESAIM Control Optim. Calc. Var. 21 (2015) 378–398] from a bounded domain to an unbounded one. The proof is based on the locally parabolic-type frequency function method. An observability estimate from measurable sets in time for the same equation is also derived.
Methane activation by closed-shell tantalum sulfide anions TaS3−
Authors: Li Qian , Liu Xiao-Xiao , Liu Qing-Yu , He Sheng-Gui
Published: September 2024

Methane is a vital feedstock while the intrinsic inertness of CH4 molecule hinders the conversion of methane under mild conditions. Investigating and understanding the mechanism of methane activation is of great importance in chemistry. In this study, tantalum sulfide anions TaS3− were generated by laser ablation method and mass-selected by a quadrupole mass filter to react with methane, ethane, and propane in an ion funnel trap reactor under thermal collision conditions. The reactant and product ions were detected by a time-of-flight mass spectrometer. Experimental results demonstrate that TaS3− is able to adsorb all of the alkane molecules and break the robust C-H bonds. Further density functional theory calculations reveal that TaS3− is a closed-shell species and effectively activates methane via the Ta/δ+–Sδ− Lewis acid-base pair (LABP, CH4+Taδ+−Sδ− → CH3-Ta-S-H). With a comparative study with NbS3− that contains the Nbδ+–Sδ− LABP, the higher reactivity of TaS3− than that of NbS3− can be attributed to the more acidity of Taδ+ than that of Nbδ+. To the best of our knowledge, this study reports the first example of gas phase species TaS3− to activate methane through the metal-sulfur LABP under thermal collision conditions.
Orthonormal aberration decomposition for circular aperture and rectangular field with extension to multiple-aperture systems
Authors: Chen Baohua , Wu Quanying , Fan Junliu , Yang Songhongkang , Li Zhixiang , Shen Donghui
Published: September 2024

A new set of orthogonal polynomials and the traditional Zernike polynomials are combined to construct the wavefront of the sparse aperture (SA) optical system. The new set of orthogonal polynomials in the rectangular domain is derived based on the Zernike polynomials. The modulation transfer functions (MTFs) of the SA system under different fields of view are calculated. The effects of some wavefront terms on the field-related MTF are analyzed. Imaging simulation and restoration are conducted for the SA system. The results indicate that the wavefront of the SA system can be represented by the combination of the new set of orthogonal polynomials and the Zernike polynomials. The former represents the field term, and the latter represents the pupil term of the wavefront. The field-related Wiener filter is constructed to restore the imaging results of the SA system, and the results show that the image quality can be improved greatly through restoration.
Applying lean production system philosophy to reduce patient waiting time in healthcare services: Simulation-based optimization and validations through experiment
Authors: Hassan Sana , Amjad Asim , Farooq Muhammad Umar , Anwar Saqib , Ammarullah Muhammad Imam
Published: September 2024

Value stream mapping (VSM) is an initial and critical tool for deploying lean concepts in the manufacturing and service sectors, including hospitals. Therefore, the aim of this research is to analyze the current working environment of a radiology department, identify the wastes in the operations by mapping the current patient flow, and test the best possible improvement plan with the help of discrete event simulation modeling using the Arena platform to develop an optimum future map to mitigate the wastes. Therefore, the current patient flow in the x-ray section of a radiology department was mapped using VSM for two types of patients named routine (RP) and procedure (PP). VSM results highlighted a high waiting time (TWT) of 188 and 3732 min for RP and PP. A total of seven scenarios were developed and analyzed to determine the impact of changes on five key performance indicators. Simulation results of the current scenario showed that there were 567 patients coming out of the system with a lead time of 200 and 926 min for RP and PP. Total waiting time obtained for RP and PP was 177 and 860 min, with a maximum wait time of 31 min/patient and an average of 43 patients in the system (WIP). The simulation results of the seventh scenario provided the best results, with 6% improvement in the number of patients getting out of the system and 75% and 55% decreased lead time for RP and PP. Total waiting time for RP and PP was reduced by 80% and 60%, with WIP falling by 62%. Arena Optimizer showed that by adding a technician and radiologist to the system, the optimum patient waiting time in the queue would be 6 min, and the lead time for RP and PP would be (160) and (884 min), respectively. Based on it, a future VSM was created; it provided a reduction of 72% and 60% in (TWT) for RP and PP, which could improve the number of patients to be entertained by the radiology services without adding any new x-ray machines. The results of the present case provide healthcare planners with a road map to discover the waste in operations since the monetary investment and organizational dedication required drive out non-value activities. Therefore, simulation helps to select the best possible improvement strategy for the system without pausing and making physical changes in busy and complex units of hospitals.
Impacts of Atlantic meridional overturning circulation weakening on Arctic amplification
Authors: Lee Yu-Chi , Liu Wei , Fedorov Alexey V. , Feldl Nicole , Taylor Patrick C.
Published: September 2024

Enhanced warming of the Arctic region relative to the rest of the globe, known as Arctic amplification, is caused by a variety of diverse factors, many of which are influenced by the Atlantic meridional overturning circulation (AMOC). Here, we quantify the role of AMOC changes in Arctic amplification throughout the twenty-first century by comparing two suites of climate model simulations under the same climate change scenario but with two different AMOC states: one with a weakened AMOC and another with a steady AMOC. We find that a weakened AMOC can reduce annual mean Arctic warming by 2 °C by the end of the century. A primary contributor to this reduction in warming is surface albedo feedback, related to a smaller sea ice loss due to AMOC slowdown. Another major contributor is the changes in ocean heat uptake. The weakened AMOC and its associated anomalous ocean heat transport divergence lead to increased ocean heat uptake and surface cooling. These two factors are inextricably linked on seasonal timescales, and their relative importance for Arctic amplification can vary by season. The weakened AMOC can also abate Arctic warming via lapse rate feedback, creating marked cooling from the surface to lower-to-mid troposphere while resulting in relatively weaker cooling in the upper troposphere. Additionally, the weakened AMOC increases the low-level cloud fraction over the North Atlantic warming hole, causing significant cooling there via shortwave (sw) cloud feedback despite the overall effect of sw cloud feedback being a slight warming of the average temperature over the Arctic.
Creating individual styles through discourse variation in Singapore Mandarin
Authors: Teo Ming Chew , Lin Jingxia
Published: September 2024

By applying the concepts of indexicality and enregisterment, this paper demonstrates how different discourse
particles and their collocations index various personae in Singapore Mandarin and how media representations enregister them within
the community. The theory of persona is shown to explain the majority of seemingly random individual differences in discourse
particle usage exhibited by two TV hosts. Finally, it is important to note that not all variation between the two hosts can be
attributed to the enactment of personae. Psychological factors, such as bilingual lexical activation, should also be considered
influences on linguistic variation, alongside linguistic and social factors.
Fostering primary students’ competences for democratic culture in EFL
Authors: Abe Motoko , Beecroft Raphaëlle
Published: September 2024

The PEACE project was a teaching unit which was designed, implemented and evaluated in two primary school classes in Japan
and Germany respectively. The project was carried out in an asynchronous virtual exchange format between the two classes. The Reference
Framework of Competences for Democratic Culture was used as a basis for the teaching unit, with the framework’s descriptors for young
learners serving as tools for designing and assessing both the teaching unit and its outcomes in the form of the participating students’
products and utterances. Using the NVivo coding software for content analysis, the study investigated the deployment of the various areas of
competence by the students during the teaching unit and compared these across the classes. This was done to gain insights into both the
context-dependency of the deployment of competences for democratic culture as well as the practicability and potentials of carrying out a
bilateral asynchronous virtual exchange aiming to promote competences for democratic culture in young learners.
Electrical discharge machining of super alloy incoloy 925: a study based on box behnken design and response surface methodology
Authors: Chaurasia Satish , Dutta Hrishikesh , Singh Samarjit , Debnath Kishore , Bhowmik Abhijit
Published: September 2024

Incoloy 925, a Nikel-based superalloy, exhibits low machinability with conventional machining techniques due to its inhomogeneous properties. Therefore, there is a need to establish a non-conventional method to efficiently machine this alloy. This work is a novel attempt to present the electric discharge machining (EDM) of the superalloy Incoloy 925 and subsequent multi-response optimization. The model for the analysis was designed using the Box Behnken Design (BBD) technique, and the Response Surface Methodology (RSM) was used for the optimization of the results. The machining was performed using a cylindrical copper tool of 11 mm diameter. The effect of pulse-on time (Ton), current, and pulse-off time (Toff) on the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) was investigated. The results from variance analysis confirmed the significance of all the three input factors. The investigation revealed that the maximum MRR (99.2154 mm3/min) was obtained at a pulse-on time of 90 μs, pulse-off time of 5 μs, and current of 30 A. The minimum TWR (0.8866 mm3/min) were achieved at Ton = 60 μs, Toff = 8 μs and current = 10 A. The microscopic images of the machined surfaces revealed very few micro-voids and globules and no cracks, resulting in a fine surface finish of 1.2436 μm, achieved through optimal discharge energy transfer and copper electrodes. The optimal values MRR, TWR, and SR according to composite desirability function are 99.1524 mm3/min, 1.0915 mm3/min, and 1.3925 μm. The experimental results were accurately predicted using RSM and an artificial neural network (ANN), with the ANN showing a predicted correlation coefficient (R) close to 1 indicating high accuracy of the model.
Room temperature dual-mode internal quantum deficiency measurement with propagated uncertainty to 0.03% (k = 2)
Authors: Heitmann Solheim Johanne , Bardalen Eivind , Gran Jarle
Published: September 2024

We present improvements in dual-mode calibration of predictable quantum efficient detectors and demonstrate the importance of calculating absolute uncertainties instead of relative uncertainties. We have implemented a new uncertainty component for the thermal fluctuations in the temperature signal which results in a propagated Type A uncertainty, matching the observed standard deviation. A new thermal drift correction method exploiting a monitor thermistor on the heat sink is relaxing the need for thermal stabilisation of the experimental set-up. With beam position uncertainty ±0.25 mm and background electrical power varying from 10 μW to 900 μW, the measured internal quantum deficiency (IQD) is in average 0.00% ± 0.03% (k = 2). The IQD exhibits clear systematic effects of beam position and background power, showing the need for improved design of dual-mode modules to further improve the uncertainty.
CZTSSe thin film solar cells with two absorber layers and a PbS layer
Authors: Zhou Xin , Xue Yuming , Wang Luoxin
Published: September 2024

In this paper, we simulated a novel CZTSSe (copper-zinc-tin-sulfide-selenide) thin film solar cell with two absorber layers and a PbS (a lead sulfide) layer by SCAPS-1D. We investigated the effect of changes in the thickness of the absorbing layer and the acceptor concentration on this cell. Meanwhile, we also optimized the bandgap width of CZTSSe and the thickness of PbS. Moreover, an effective method has been applied with the aim of boosting conversion efficiency by adding a BSF (back surface field) layer to the cell. The BSF layer helps to enhance optical behavior and reduces recombination losses, consequently reducing the Voc (open circuit voltage) deficit. With the highest conversion efficiency calculated in the simulation, a cell conversion efficiency of 27.70% can be achieved, which is significantly higher than the basic structure, providing a large electrical power as well as a more optimal filling factor at the same time.
Modulation of plant transcription factors and priming of stress tolerance by plant growth-promoting bacteria: a systematic review
Authors: Kaleh Abdussabur M , Singh Pooja , Chua Kah Ooi , Harikrishna Jennifer Ann
Published: September 2024

Background

Plant growth-promoting bacteria (PGPB) have been shown to improve plant growth and stress tolerance through mechanisms including improved access to nutrients and biotic competition with pathogens. As such, the use of PGPB can help to address challenges to crop productivity, but information on interactions between PGPB and their plant hosts, especially at the level of gene regulation, is distributed across diverse studies involving several different plants and PGPB.

Scope

For this review, we analysed recent research publications reporting specifically on plant transcription factor (TF) expression in association with PGPB, to determine if there are any common findings and to identify gaps that offer opportunities for focused future research.

Conclusions

The inoculation of plants with PGPB elicits a dynamic and temporal response. Initially, there is an upregulation of defence-responsive TFs, followed by their downregulation in an intermediate phase, and finally, another upregulation, providing longer term stress tolerance. PGPB priming activates plant defences in the form of induced systemic resistance (ISR), often via the MAMP/MAPK pathways and involving one or more of the major plant hormone-signalling pathways and their crosstalk. Following PGPB priming, the TF families most commonly reported as expressed across different plants and for different pathogens are ERF and WRKY, while the TFs most commonly expressed across different plants for different abiotic stresses are ERF and DREB. There were inconsistencies between studies regarding the timing of the shift from the initial phase to the intermediate phase, and some of the TFs expressed during this process have not been fully characterized. This calls for more research to investigate the regulatory functions and phases of TF expression, to enhance crop resilience. Most reports on abiotic stresses have focused on salinity and drought, with fewer studies addressing nutrient deficiency, heavy metals, flooding and other stresses, highlighting the need for further research in these areas.
Semi-parametric benchmark dose analysis with monotone additive models
Authors: Stringer Alex , Akkaya Hocagil Tugba , Cook Richard J , Ryan Louise M , Jacobson Sandra W , Jacobson Joseph L
Published: September 2024

Benchmark dose analysis aims to estimate the level of exposure to a toxin associated with a clinically significant adverse outcome and quantifies uncertainty using the lower limit of a confidence interval for this level. We develop a novel framework for benchmark dose analysis based on monotone additive dose-response models. We first introduce a flexible approach for fitting monotone additive models via penalized B-splines and Laplace-approximate marginal likelihood. A reflective Newton method is then developed that employs de Boor’s algorithm for computing splines and their derivatives for efficient estimation of the benchmark dose. Finally, we develop a novel approach for calculating benchmark dose lower limits based on an approximate pivot for the nonlinear equation solved by the estimated benchmark dose. The favorable properties of this approach compared to the Delta method and a parameteric bootstrap are discussed. We apply the new methods to make inferences about the level of prenatal alcohol exposure associated with clinically significant cognitive defects in children using data from six NIH-funded longitudinal cohort studies. Software to reproduce the results in this paper is available online and makes use of the novel semibmd  R package, which implements the methods in this paper.
collectNET: a web server for integrated inference of cell–cell communication network
Authors: Pan Yan , Gao Zijing , Cui Xuejian , Li Zhen , Jiang Rui
Published: September 2024

Cell–cell communication (CCC) through ligand–receptor (L–R) pairs forms the cornerstone for complex functionalities in multicellular organisms. Deciphering such intercellular signaling can contribute to unraveling disease mechanisms and enable targeted therapy. Nonetheless, notable biases and inconsistencies are evident among the inferential outcomes generated by current methods for inferring CCC network. To fill this gap, we developed collectNET (http://health.tsinghua.edu.cn/collectnet) as a comprehensive web platform for analyzing CCC network, with efficient calculation, hierarchical browsing, comprehensive statistics, advanced searching, and intuitive visualization. collectNET provides a reliable online inference service with prior knowledge of three public L–R databases and systematic integration of three mainstream inference methods. Additionally, collectNET has assembled a human CCC atlas, including 126 785 significant communication pairs based on 343 023 cells. We anticipate that collectNET will benefit researchers in gaining a more holistic understanding of cell development and differentiation mechanisms.

Database URL: http://health.tsinghua.edu.cn/collectnet.