bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dense geodesics, tower alignment, and the Sharpened Distance Conjecture
Authors: Etheredge Muldrow 
Published: January 2024

Abstract
The Sharpened Distance Conjecture and Tower Scalar Weak Gravity Conjecture are closely related but distinct conjectures, neither one implying the other. Motivated by examples, I propose that both are consequences of two new conjectures: 1. The infinite distance geodesics passing through an arbitrary point ϕ in the moduli space populate a dense set of directions in the tangent space at ϕ. 2. Along any infinite distance geodesic, there exists a tower of particles whose scalar-charge-to-mass ratio (–∇log m) projection everywhere along the geodesic is greater than or equal to $$ 1/\sqrt{d-2} $$
1
/

d
−
2

. I perform several nontrivial tests of these new conjectures in maximal and half-maximal supergravity examples. I also use the Tower Scalar Weak Gravity Conjecture to conjecture a sharp bound on exponentially heavy towers that accompany infinite distance limits.
Lorentzian Robin Universe
Authors: Ailiga Manishankar , Mallik Shubhashis , Narain Gaurav 
Published: January 2024

Abstract
In this paper, we delve into the gravitational path integral of Gauss-Bonnet gravity in four spacetime dimensions, in the mini-superspace approximation. Our primary focus lies in investigating the transition amplitude between distinct boundary configurations. Of particular interest is the case of Robin boundary conditions, known to lead to a stable Universe in Einstein-Hilbert gravity, alongside Neumann boundary conditions. To ensure a consistent variational problem, we supplement the bulk action with suitable surface terms. This study leads us to compute the necessary surface terms required for Gauss-Bonnet gravity with the Robin boundary condition, which wasn’t known earlier. Thereafter, we perform an exact computation of the transition amplitude. Through ħ → 0 analysis, we discover that the Gauss-Bonnet gravity inherently favors the initial configuration, aligning with the Hartle-Hawking no-boundary proposal. Remarkably, as the Universe expands, it undergoes a transition from the Euclidean (imaginary time) to the Lorentzian signature (real time). To further reinforce our findings, we employ a saddle point analysis utilizing the Picard-Lefschetz methods. The saddle point analysis allows us to find the initial configurations which lead to Hartle-Hawking no-boundary Universe that agrees with the exact computations. Our study concludes that for positive Gauss-Bonnet coupling, initial configurations corresponding to the Hartle-Hawking no-boundary Universe gives dominant contribution in the gravitational path-integral.
Massive ambitwistor-strings; twistorial models
Authors: Albonico Giulia , Geyer Yvonne , Mason Lionel 
Published: January 2024

Abstract
Ambitwistor-strings are chiral strings whose targets are spaces of complex massless particles, and whose correlation functions directly lead to simple, compact formulae for scattering amplitudes and loop integrands for massless gauge and gravity theories. This article extends the framework to massive particles in 4d, obtained via a symmetry reduction of higher dimensional massless models based on twistors. The target space of the resulting models turns out to be the phase space of 4d massive particles in a twistorial representation, and the worldsheet theory agrees with the two-twistor string previously introduced by the authors. The paper has been written so as to be largely self-contained. We discuss two interesting classes of massive theories in detail. For gauge theories, the reduction procedure is explicitly adapted to supersymmetric gauge theories on the Coulomb branch. For supergravity theories, the reduction is adapted to give theories obtained via Cremmer, Scherk & Schwartz (CSS) reduction, with broken supersymmetry and massive multiplets. The reduction procedure gives explicit and systematic rules to obtain amplitudes for all these theories and their amplitudes from two compact master formulae that have their origins in 6d based on the polarized scattering equations; in the CSS case the formulae are new, and in both cases their derivation is systematic. The freedom to include mass allows the definition of a loop insertion operator, thereby extending the formulae to 1-loop. Unlike the massless 4d twistorial models, these all display a perfect double copy structure, here incorporating massive particles in the relationship between gauge theory and CSS supergravity amplitudes.
The Hilbert space of de Sitter quantum gravity
Authors: Chakraborty Tuneer , Chakravarty Joydeep , Godet Victor , Paul Priyadarshi , Raju Suvrat 
Published: January 2024

Abstract
We obtain solutions of the Wheeler-DeWitt equation with positive cosmological constant for a closed universe in the large-volume limit. We argue that this space of solutions provides a complete basis for the Hilbert space of quantum gravity in an asymptotically de Sitter spacetime. Our solutions take the form of a universal phase factor multiplied by distinct diffeomorphism invariant functionals, with simple Weyl transformation properties, that obey the same Ward identities as a CFT partition function. The Euclidean vacuum corresponds to a specific choice of such a functional but other choices are equally valid. Each functional can be thought of as specifying a “theory” and, in this sense, the space of solutions is like “theory space”. We describe another basis for the Hilbert space where all states are represented as excitations of the vacuum that have a specific constrained structure. This gives the finite GN generalization of the basis proposed by Higuchi in terms of group averaging, which we recover in the nongravitational limit.
Primordial black holes as dark matter: interferometric tests of phase transition origin
Authors: Baldes Iason , Olea-Romacho María Olalla 
Published: January 2024

Abstract
We show that primordial black holes — in the observationally allowed mass window with fPBH = 1 — formed from late nucleating patches in a first order phase transition imply upcoming gravitational wave interferometers will see a large stochastic background arising from the bubble collisions. As an example, we use a classically scale invariant B – L model, in which the right handed neutrinos explain the neutrino masses and leptogenesis, and the dark matter consists of primordial black holes. The conclusion regarding the gravitational waves is, however, expected to hold model independently for black holes coming from such late nucleating patches.
Polyether Ketone Ketone (PEKK) matrix composites for material extrusion additive manufacturing
Authors: Rashed Kaifur , Kafi Abdullah , Simons Ranya , Dell’Olio Mel , Bateman Stuart 
Published: January 2024

AbstractDespite the widespread use of fused filament fabrication (FFF) (an extrusion-based additive manufacturing process) to manufacture end-use parts for the aerospace industry, limited materials are available within this process that can be used for structural applications in the harsh space environment. Currently available high-performance polymers need to be improved by incorporating additives within the polymer matrix to achieve multi-functional properties. Additives such as graphene, graphene oxide, carbon nanotubes and boron carbide are known to improve mechanical and thermal properties and radiation shielding. This study aims to understand if these additives can be successfully incorporated into PEKK matrix to manufacture printable filaments for FFF. Graphene, graphene oxide (GO) and boron carbide (B4C) were compatibilised with PEKK matrix, and their mechanical, thermal and rheological properties were analysed and compared with commercially available carbon fibre and carbon nanotube-reinforced PEKK where appropriate. As rheological properties of the formulations confirmed that they were printable, filaments for FFF were then manufactured. Graphene–PEKK was the most printable filament followed by GO–PEKK while B4C–PEKK was not printable. TEM images of filament cross-section showed good dispersion of graphene and graphene oxide, while boron carbide formed large agglomerates; B4C also presented feeding issues due to its hardness which affected its printability. Dispersion of the additives was also confirmed by studying their X-ray diffraction (XRD) patterns, and chemical structures were assessed using FT-IR spectroscopy. Finally, parts were printed using selected composite filaments, and their porosity and surface roughness were compared with neat PEKK and commercial CNT-reinforced PEKK to develop an understanding of metrology and bulk material properties of the composites.
Mid-term Clinical Outcome of Microvascular Gracilis Muscle Flaps for Defects of the Hand
Authors: Pastor Tatjana , Meier Rahel , Merky Dominique , Haug Luzian , Pastor Torsten , Zubler Cédric , Vögelin Esther 
Published: January 2024

AbstractPurpose: Gracilis muscle flaps are useful to cover defects of the hand. However, there are currently no studies describing outcome measurements after covering soft tissue defects using free flaps in the hand. Aim: To analyze mid-term results of gracilis muscle flap coverage for defects on the hand, with regard to functional and esthetic integrity. Methods: 16 patients aged 44.3 (range 20–70) years were re-examined after a mean follow-up of 23.6 (range 2–77) months. Mean defect size was 124 (range 52–300) cm2 located palmar (n = 9), dorsal (n = 6), or radial (n = 1). All flaps were performed as microvascular muscle flaps, covered by split thickness skin graft. Results: Flaps survived in 15 patients. 6 patients required reoperations. Reasons for revisions were venous anastomosis failure with total flap loss (n = 1) requiring a second gracilis muscle flap; necrosis at the tip of the flap (n = 1) with renewed split thickness skin cover. A surplus of the flap (n = 2) required flap thinning and scar corrections were performed in 2 patients. Mean grip strength was 25% (range 33.3–96.4%) compared to the contralateral side and mean patient-reported satisfaction 1.4 (range 1–3) (1 = excellent; 4 = poor). Conclusions: Gracilis muscle flaps showed a survival rate of 94%. Patients showed good clinical outcomes with acceptable wrist movements and grip strength as well as high reported satisfaction rates. Compared to fasciocutaneous free flaps, pliability and thinness especially on the palmar aspect of the hand are advantageous. Hence, covering large defects of the hand with a gracilis muscle flap can be a very satisfactory procedure.Level of evidence: IV observational.
Genetic analysis of late-maturity α-amylase in twelve wheat populations
Authors: Fairlie William , Norman Adam , Edwards James , Mather Diane E. , Kuchel Haydn 
Published: January 2024

Abstract
Main conclusion
Genetic loci, particularly those with an effect in the independent panel, could be utilised to further reduce LMA expression when used with favourable combinations of genes known to affect LMA.

Abstract
Late maturity α-amylase (LMA) is a grain quality defect involving elevated α-amylase within the aleurone of wheat (Triticum aestivum L.) grains. The genes known to affect expression are the reduced height genes Rht-B1 (chromosome 4B) and Rht-D1 (chromosome 4D), and an ent-copalyl diphosphate synthase gene (LMA-1) on chromosome 7B. Other minor effect loci have been reported, but these are poorly characterised and further genetic understanding is needed. In this study, twelve F4-derived populations were created through single seed descent, genotyped and evaluated for LMA. LMA-1 haplotype C and the Rht-D1b allele substantially reduced LMA expression. The alternative dwarfing genes Rht13 and Rht18 had no significant effect on LMA expression. Additional quantitative trait loci (QTL) were mapped at 16 positions in the wheat genome. Effects on LMA expression were detected for four of these QTL in a large independent panel of Australian wheat lines. The QTL detected in mapping populations and confirmed in the large independent panel provide further opportunity for selection against LMA, especially if combined with Rht-D1b and/or favourable haplotypes of LMA-1.
Expansion of the complex genotypic and phenotypic spectrum of FGFR2-associated neurocutaneous syndromes
Authors: Schmidt Julia , Kaulfuß Silke , Ott Hagen , Gaubert Marianne , Reintjes Nadine , Bremmer Felix , Dreha-Kulaczewski Steffi , Stroebel Philipp , Yigit Gökhan , Wollnik Bernd 
Published: January 2024

AbstractThe fibroblast growth factor receptors comprise a family of related but individually distinct tyrosine kinase receptors. Within this family, FGFR2 is a key regulator in many biological processes, e.g., cell proliferation, tumorigenesis, metastasis, and angiogenesis. Heterozygous activating non-mosaic germline variants in FGFR2 have been linked to numerous autosomal dominantly inherited disorders including several craniosynostoses and skeletal dysplasia syndromes. We report on a girl with cutaneous nevi, ocular malformations, macrocephaly, mild developmental delay, and the initial clinical diagnosis of Schimmelpenning–Feuerstein–Mims syndrome, a very rare mosaic neurocutaneous disorder caused by postzygotic missense variants in HRAS, KRAS, and NRAS. Exome sequencing of blood and affected skin tissue identified the mosaic variant c.1647=/T > G p.(Asn549=/Lys) in FGFR2, upstream of the RAS signaling pathway. The variant is located in the tyrosine kinase domain of FGFR2 in a region that regulates the activity of the receptor and structural mapping and functional characterization revealed that it results in constitutive receptor activation. Overall, our findings indicate FGFR2-associated neurocutaneous syndrome as the accurate clinical-molecular diagnosis for the reported individual, and thereby expand the complex genotypic and phenotypic spectrum of FGFR-associated disorders. We conclude that molecular analysis of FGFR2 should be considered in the genetic workup of individuals with the clinical suspicion of a mosaic neurocutaneous condition, as the knowledge of the molecular cause might have relevant implications for genetic counseling, prognosis, tumor surveillance and potential treatment options.
Non-alcoholic fatty liver disease in patients with morbid obesity: the gut microbiota axis as a potential pathophysiology mechanism
Authors: Cornejo-Pareja Isabel , Amiar Mohamed Reda , Ocaña-Wilhelmi Luís , Soler-Humanes Rocío , Arranz-Salas Isabel , Garrido-Sánchez Lourdes , Gutiérrez-Repiso Carolina , Tinahones Francisco Jose 
Published: January 2024

Abstract
Background/aim
Alterations in gut microbiota are associated with the pathogenesis of metabolic diseases, including metabolic-associated fatty liver disease (MAFLD). The aim of this study was to evaluate gut microbiota composition and functionality in patients with morbid obesity with different degrees of MAFLD, as assessed by biopsy.

Subjects/methods
110 patients with morbid obesity were evaluated by biopsy obtained during bariatric surgery for MAFLD. Stool samples were collected prior to surgery for microbiota analysis.

Results
Gut microbiota from patients with steatosis and non-alcoholic steatohepatitis (NASH) were characterized by an enrichment in Enterobacteriaceae (an ethanol-producing bacteria), Acidaminococcus and Megasphaera and the depletion of Eggerthellaceae and Ruminococcaceae (SCFA-producing bacteria). MAFLD was also associated with enrichment of pathways related to proteinogenic amino acid degradation, succinate production, menaquinol-7 (K2-vitamin) biosynthesis, and saccharolytic and proteolytic fermentation. Basic histological hepatic alterations (steatosis, necroinflammatory activity, or fibrosis) were associated with specific changes in microbiota patterns. Overall, the core microbiome related to basic histological alterations in MAFLD showed an increase in Enterobacteriaceae and a decrease in Ruminococcaceae. Specifically, Escherichia coli was associated with steatosis and necroinflammatory activity, whilst Escherichia-shigella was associated with fibrosis and necroinflammatory activity.

Conclusions
We established a link between gut microbiota alterations and histological injury in liver diagnosis using biopsy. Harmful products such as ethanol or succinate may be involved in the pathogenesis and progression of MAFLD. Thus, these alterations in gut microbiota patterns and their possible metabolic pathways could add information to the classical predictors of MAFLD severity and suggest novel metabolic targets.
Experimental study of long-term catalytic effect on hydrogen generation G value of water by gamma-ray irradiation and hydrogen diffusion analysis in Compacted Hulls and End-Piece waste
Authors: Eto Junji , Kawai Masaki , Matsumoto Masaaki , Tanaka Hirohisa , Hino Ryutaro , Terada Atsuhiko , Taniguchi Masashi , Sugiyama Hitoshi 
Published: January 2024

AbstractIn this study, it was evaluated the long-term catalytic effect and catalyst poisoning effect of gamma-ray irradiation on zirconium molybdate hydrate in the presence of three-way catalysts. The results indicated that the three-way catalyst was effective in suppressing the increase in hydrogen concentration due to radiolysis without being affected by poisoning. In addition, hydrogen diffusion analysis of the compressed hull and endpiece waste shows that hydrogen flows well through the waste and is suppressed by a three-way catalyst located in the center of the waste headspace.
Linking the future likelihood of large fires to occur on mountain slopes with fuel connectivity and topography
Authors: Conedera Marco , Feusi Jeremy , Pezzatti Gianni Boris , Krebs Patrik 
Published: January 2024

AbstractIn the long run, ongoing climate change is expected to alter fuel production as well as the frequency and severity of fire weather, which may result in an unprecedented frequency of extreme fire events. In this paper we propose a simplified and spatially explicit method to assess the probability of experiencing large fires, based on topography (slope length) as well as extent and aggregation of the forested area (fuel connectivity). We considered 21 homogeneous pyroregions covering entire Switzerland as a study case and computed the length of the upslope paths within the forested areas, simulating ignition points on a systematic 100 × 100 m square grid. We then compared the obtained path lengths for each pyroregion with selected historical large forest fire statistics (e.g., mean area of the largest 5% of fires, maximum burnt area per fire) collected over the course of the last 30 years. This resulted in rather high R2 values, ranging from 0.558 to 0.651. The proposed approach was shown to allow for an easy identification and geo-localization of potential hotspots in terms of the likelihood for large fires to occur in mountainous regions, which is a prerequisite for a targeted planning of fire management measures aimed at preventing large fires and related post-fire gravitative natural hazards.
Enhancing catalytic performance, coke resistance, and stability with strontium-promoted Ni/WO3-ZrO2 catalysts for methane dry reforming
Authors: Elnour Ahmed Yagoub , Fakeeha Anis Hamza , Ibrahim Ahmed Aidid , Osman Ahmed I. , Abasaeed Ahmed Elhag , Adil Syed Farooq , Kumar Rawesh , Al-Fatesh Ahmed S. 
Published: January 2024

AbstractThe first step of the DRM reaction is just the decomposition of CH4 into CH4−x (x = 1–4). The next step comprises two steps, namely the oxidation of CH4−x into syngas (by CO2) and the self-polymerization of CH4−x species. The earlier one is known as dry reforming of methane (DRM), and the latter one generates carbon deposits over the catalyst surface. In this study, we investigated the impact of 1–3 wt% Sr over Ni-based catalysts on a ZrO2-WO3 support on the catalytic activity and coke deposit. Various characterization techniques such as thermogravimetric analysis, X-ray diffraction, Raman spectroscopy, temperature-programed oxidation, temperature-programed reduction, and temperature-programed desorption were used to assess the physicochemical properties of the fresh and spent catalysts. The addition of 2wt% Sr promoter significantly improves the catalyst’s basicity in strong basic sites region through Sr2+ mediated interaction of CO2 species as well as inhibits the deposition of carbyne type carbon. Enhanced CO2 interaction results into the potential oxidation of carbon deposit and the highest CH4 conversion, reaching 60% up to 470 min TOS at a reaction temperature of 700 ℃.
Graphical abstract
The Effect of Social Cohesion on Subjective Individual Quality of Life in European Countries
Authors: Bottoni Gianmaria , Addeo Felice 
Published: January 2024

AbstractMany scholars have studied the effects of economic conditions on subjective well-being, but scarce attention has been paid to the effect of cultural and social determinants on quality of life. This study aims to analyse the effect of social cohesion considered as a characteristic of a country on subjective quality of life. In addition, we also tested the moderating effect of social cohesion on the relationship between income and placement in society with quality of life. To test our hypotheses we estimated a multilevel regression model. First, we estimated the null model, which showed that almost a quarter of the variance in quality of life is located at country level. Second, we included in the model all the level-1 predictors. This model highlighted that self-evaluated position on the social ladder has a larger positive effect than income on quality of life. In the third step, we added country-level predictors. Controlling for other macro factors—GDP, Life Expectancy, Gini coefficient and Homicide rate—and individual-level variables, we shows that Cohesion exerts a positive effect on subjective quality of life. The model also points out that country’s economic conditions (measured by GDP) do not affect quality of life when we control this relationship for social cohesion. Interestingly, also the within-country economic disparities (measured by Gini coefficient) do not seem to affect quality of life when cohesion is taken into account. Finally, we also shows that the positive effect of income on quality of life is moderated by cohesion. In other words, income is a relatively less important factor in determining quality of life in countries with higher levels of cohesion. In the same way, individuals’ position and perception of their placement on the social ladder affects in a lesser extent their quality of life in those countries that have higher degrees of cohesion.