bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cosmic ray transport in large-amplitude turbulence with small-scale field reversals
Authors: Kempski Philipp , Fielding Drummond B , Quataert Eliot , Galishnikova Alisa K , Kunz Matthew W , Philippov Alexander A , Ripperda Bart 
Published: September 2023

ABSTRACT
The nature of cosmic ray (CR) transport in the Milky Way remains elusive. The predictions of current microphysical CR transport models in magnetohydrodynamic (MHD) turbulence are drastically different from what is observed. These models usually focus on MHD turbulence with a strong guide field and ignore the impact of turbulent intermittency on particle propagation. This motivates our studying the alternative regime of large-amplitude turbulence with δB/B0 ≫ 1, in which intermittent small-scale magnetic field reversals are ubiquitous. We study particle transport in such turbulence by integrating trajectories in stationary snapshots. To quantify spatial diffusion, we use a set-up with continuous particle injection and escape, which we term the turbulent leaky box. We find that particle transport is very different from the strong guide-field case. Low-energy particles are better confined than high-energy particles, despite less efficient pitch-angle isotropization at small energies. In the limit of weak guide field, energy-dependent confinement is driven by the energy-dependent (in)ability to follow reversing magnetic field lines exactly and by the scattering in regions of ‘resonant curvature’, where the field line bends on a scale that is of the order of the local particle gyro-radius. We derive a heuristic model of particle transport in magnetic folds that approximately reproduces the energy dependence of transport found numerically. We speculate that CR propagation in the Galaxy is regulated by the intermittent field reversals highlighted here and discuss the implications of our findings for CR transport in the Milky Way.
An astrometric approach to measuring the colour of an object
Authors: Guo B F , Peng Q Y , Fang X Q , Lin F R 
Published: September 2023

ABSTRACT
The colour of a star is a critical feature to reflect its physical property such as the temperature. The colour index is usually obtained via absolute photometry, which is demanding for weather conditions and instruments. In this work, we present an astrometric method to measure the catalogue-matched colour index of an object based on the effect of differential colour refraction (DCR). Specifically, we can observe an object using only one filter or alternately using two different filters. Through the difference of the DCR effect compared with reference stars, the catalogue-matched colour index of an object can be conveniently derived. Hence, we can perform DCR calibration and obtain its accurate and precise positions even if observed with Null filter during a large range of zenith distances, by which the limiting magnitude and observational efficiency of the telescope can be significantly improved. This method takes advantage of the DCR effect and builds a link between astrometry and photometry. In practice, we measure the colour indices and positions of Himalia (the sixth satellite of Jupiter) using 857 CCD frames over 8 nights by two telescopes. Totally, the mean colour index BP − RP (Gaia photometric system) of Himalia is 0.750 ± 0.004 mag. Through the rotational phased colour index analysis, we find two places with their colour indices exceeding the mean ± 3σ.
CO and [C ii] line emission of molecular clouds: the impact of stellar feedback and non-equilibrium chemistry
Authors: Ebagezio S , Seifried D , Walch S , Nürnberger P C , Rathjen T-E , Naab T 
Published: September 2023

ABSTRACT
We analyse synthetic 12CO, 13CO, and [C ii] emission maps of molecular cloud (MC) simulations from the SILCC-Zoom project. We present radiation, magnetohydrodynamic zoom-in simulations of individual clouds, both with and without radiative stellar feedback, forming in a turbulent multiphase interstellar medium following on-the-fly the evolution of e.g. H2, CO, and C+. We introduce a novel post-processing routine based on cloudy which accounts for higher ionization states of carbon due to stellar radiation in H ii regions. Synthetic emission maps of [C ii] in and around feedback bubbles show that the bubbles are largely devoid of [C ii], as recently found in observations, which we attribute to the further ionization of C+ into C2+. For both 12CO and 13CO, the cloud-averaged luminosity ratio, $L_\rm {CO}/L_\rm {[C\, \small {II}]}$, can neither be used as a reliable measure of the H2 mass fraction nor of the evolutionary stage of the clouds. We note a relation between the $I_\rm {CO}/I_\rm {[C\, \small {II}]}$ intensity ratio and the H2 mass fraction for individual pixels of our synthetic maps. The scatter, however, is too large to reliably infer the H2 mass fraction. Finally, the assumption of chemical equilibrium overestimates H2 and CO masses by up to 150 and 50 per cent, respectively, and $L_\rm {CO}$ by up to 60 per cent. The masses of H and C+ would be underestimated by 65 and 30 per cent, respectively, and $L_\rm {[C\, \small {II}]}$ by up to 35 per cent. Hence, the assumption of chemical equilibrium in MC simulations introduces intrinsic errors of a factor of 2 in chemical abundances, luminosities, and luminosity ratios.
Two-screen scattering in CRAFT FRBs
Authors: Sammons Mawson W , Deller Adam T , Glowacki Marcin , Gourdji Kelly , James C W , Prochaska J Xavier , Qiu Hao , Scott Danica R , Shannon R M , Trott C M 
Published: September 2023

ABSTRACT
Temporal broadening is a commonly observed property of fast radio bursts (FRBs), associated with turbulent media which cause radiowave scattering. Similarly to dispersion, scattering is an important probe of the media along the line of sight to an FRB source, such as the circumburst or circumgalactic media (CGM). Measurements of characteristic scattering times alone are insufficient to constrain the position of the dominant scattering media along the line of sight. However, where more than one scattering screen exists, Galactic scintillation can be leveraged to form strong constraints. We quantify the scattering and scintillation in 10 FRBs with (1) known host galaxies and redshifts and (2) captured voltage data enabling high-time resolution analysis. We find strong evidence for two screens in three cases. For FRBs 20190608B and 20210320C, we find evidence for scattering screens less than approximately 16.7 and 3000 kpc, respectively, from their sources, consistent with the scattering occurring in the circumburst environment, the host interstellar medium (ISM) or the CGM. For FRB 20201124A, we find a low modulation index that evolves over the burst’s scattering tail, indicating the presence of a scattering screen ≈9 kpc from the host, and excluding the circumburst environment from potential scattering sites. By assuming that pulse broadening is contributed by the host galaxy ISM or circumburst environment, the lack of observed scintillation in four FRBs in our sample suggests that existing models may be poor estimators of scattering times associated with the Milky Way’s ISM, similar to the anomalously low scattering observed for FRB 20201124A.
Swift Deep Galactic Plane Survey classification of Swift J170800−402551.8 as a candidate intermediate polar cataclysmic variable
Authors: O’Connor B , Göğüş E , Hare J , Mukai K , Huppenkothen D , Brink J , Buckley D A H , Levan A , Baring M G , Stewart R , Kouveliotou C , Woudt P , Bellm E , Cenko S B , Evans P A , Granot J , Hailey C , Harrison F , Hartmann D , van der Horst A J , Kaper L , Kennea J A , Potter S B , Slane P O , Stern D , Wijers R A M J , Younes G 
Published: September 2023

ABSTRACT
Here, we present the results of our multiwavelength campaign aimed at classifying Swift J170800−402551.8 as part of the Swift Deep Galactic Plane Survey (DGPS). We utilized Target of Opportunity (ToO) observations with the Neil Gehrels Swift Observatory, Chandra X-ray Observatory, Neutron star Interior Composition Explorer (NICER), X-ray Multi-Mirror Mission (XMM–Newton), Nuclear Spectroscopic Telescope Array (NuSTAR), and the Southern African Large Telescope (SALT), as well as multiwavelength archival observations from Gaia, VST Photometric Hα Survey, and VISTA Variables in the Via Lactea. The source displays a periodicity of 784 s in our XMM–Newton observation. The X-ray spectrum (XMM–Newton and NuSTAR) can be described by thermal bremsstrahlung radiation with a temperature of kT ≈ 30 keV. The phase-folded X-ray light curve displays a double-peaked, energy-dependent pulse profile. We used Chandra to precisely localize the source, allowing us to identify and study the multiwavelength counterpart. Spectroscopy with SALT identified a Balmer H α line, and potential He i lines, from the optical counterpart. The faintness of the counterpart (r ≈ 21 AB mag) favours a low-mass donor star. Based on these criteria, we classify Swift J170800−402551.8 as a candidate intermediate polar cataclysmic variable, where the spin period of the white dwarf is 784 s.
Search for directional associations between baikal gigaton volume detector neutrino-induced cascades and high-energy astrophysical sources
Authors: Allakhverdyan V A , Avrorin A D , Avrorin A V , Aynutdinov V M , Bardačová Z , Belolaptikov I A , Bondarev E A , Borina I V , Budnev N M , Chepurnov A S , Dik V Y , Domogatsky G V , Doroshenko A A , Dvornický R , Dyachok A N , Dzhilkibaev Zh-A M , Eckerová E , Elzhov T V , Fajt L , Gafarov A R , Golubkov K V , Gorshkov N S , Gress T I , Kebkal K G , Kharuk I , Khramov E V , Kolbin M M , Konischev K V , Korobchenko A V , Koshechkin A P , Kozhin V A , Kruglov M V , Kulepov V F , Lemeshev Y E , Milenin M B , Mirgazov R R , Naumov D V , Nikolaev A S , Petukhov D P , Pliskovsky E N , Rozanov M I , Ryabov E V , Safronov G B , Seitova D , Shaybonov B A , Shelepov M D , Shilkin S D , Shirokov E V , Šimkovic F , Sirenko A E , Skurikhin A V , Solovjev A G , Sorokovikov M N , Štekl I , Stromakov A P , Suvorova O V , Tabolenko V A , Ulzutuev B B , Yablokova Y V , Zaborov D N , Zavyalov S I , Zvezdov D Y , Kosogorov N A , Kovalev Y Y , Lipunova G V , Plavin A V , Semikoz D V , Troitsky S V ,   Baikal-GVD Collaboration
Published: September 2023

ABSTRACT
Baikal-GVD has recently published its first measurement of the diffuse astrophysical neutrino flux, performed using high-energy cascade-like events. We further explore the Baikal-GVD cascade data set collected in 2018–2022, with the aim to identify possible associations between the Baikal-GVD neutrinos and known astrophysical sources. We leverage the relatively high angular resolution of the Baikal-GVD neutrino telescope (2–3 deg.), made possible by the use of liquid water as the detection medium, enabling the study of astrophysical point sources even with cascade events. We estimate the telescope’s sensitivity in the cascade channel for high-energy astrophysical sources and refine our analysis prescriptions using Monte-Carlo simulations. We primarily focus on cascades with energies exceeding 100 TeV, which we employ to search for correlation with radio-bright blazars. Although the currently limited neutrino sample size provides no statistically significant effects, our analysis suggests a number of possible associations with both extragalactic and Galactic sources. Specifically, we present an analysis of an observed triplet of neutrino candidate events in the Galactic plane, focusing on its potential connection with certain Galactic sources, and discuss the coincidence of cascades with several bright and flaring blazars.
Constraining the geometry of the reflection nebula NGC 2023 with [O i]: emission & absorption
Authors: Mookerjea Bhaswati , Sandell Göran , Güsten Rolf , Wiesemeyer Helmut , Okada Yoko , Jacobs Karl 
Published: September 2023

ABSTRACT
We have mapped the NGC 2023 reflection nebula in the 63 and 145 $\mu$m transitions of [O i] and the 158 $\mu$m [C ii] spectral lines using the heterodyne receiver upGREAT on SOFIA. The observations were used to identify the diffuse and dense components of the photon-dominated region (PDR) traced by the [C ii] and [O i] emission, respectively. The velocity-resolved observations reveal the presence of a significant column of low-excitation atomic oxygen, seen in absorption in the [O i] 63 $\mu$m spectra, amounting to about 20–60 per cent of the oxygen column seen in emission in the [O i] 145 $\mu$m spectra. Some self-absorption is also seen in [C ii], but for the most part it is hardly noticeable. The [C ii] and [O i] 63 $\mu$m spectra show strong red- and blue-shifted wings due to photoevaporation flows especially in the south-eastern and southern part of the reflection nebula, where comparison with the mid- and high-J CO emission indicates that the C+ region is expanding into a dense molecular cloud. Using a two-slab toy model the large-scale self-absorption seen in [O i] 63 $\mu$m is readily explained as originating in foreground low-excitation gas associated with the source. Similar columns have also been observed recently in other Galactic PDRs. These results have two implications: for the velocity-unresolved extragalactic observations this could impact the use of [O i] 63 $\mu$m as a tracer of massive star formation and secondly, the widespread self-absorption in [O i] 63 $\mu$m leads to underestimate of the column density of atomic oxygen derived from this tracer and necessitates the use of alternative indirect methods.
Paraxerus cepapi (Rodentia: Sciuridae)
Authors: Banotai Chris M , Mazzamuto Maria Vittoria , Koprowski John L 
Published: September 2023

Abstract
Paraxerus cepapi (A. Smith, 1836) is a rodent commonly called Smith’s bush squirrel. Pelage color varies throughout its distribution, with grayer individuals in the western reaches of its distribution and more brown individuals in eastern areas. Paraxerus cepapi is 1 of 11 species in the genus Paraxerus and is found throughout sub-Saharan Africa. The International Union for the Conservation of Nature (IUCN) considers P. cepapi to be a species of “Least Concern” (LC), listing no major threats.
Alterations in EGFR and PDGFRA are associated with the localization of contrast-enhancing lesions in glioblastoma
Authors: Makino Ryutaro , Higa Nayuta , Akahane Toshiaki , Yonezawa Hajime , Uchida Hiroyuki , Takajo Tomoko , Fujio Shingo , Kirishima Mari , Hamada Taiji , Yamahata Hitoshi , Kamimura Kiyohisa , Yoshiura Takashi , Yoshimoto Koji , Tanimoto Akihide , Hanaya Ryosuke 
Published: September 2023

Abstract

Background
Glioblastoma (GBM) is a malignant brain tumor, with radiological and genetic heterogeneity. We examined the association between radiological characteristics and driver gene alterations.

Methods
We analyzed the driver genes of 124 patients with IDH wild-type GBM with contrast enhancement using magnetic resonance imaging. We used a next-generation sequencing panel to identify mutations in driver genes and matched them with radiological information. Contrast-enhancing lesion localization of GBMs was classified into 4 groups based on their relationship with the subventricular zone (SVZ) and cortex (Ctx).

Results
The cohort included 69 men (55.6%) and 55 women (44.4%) with a mean age of 66.4 ± 13.3 years. EGFR and PDGFRA alterations were detected in 28.2% and 22.6% of the patients, respectively. Contrast-enhancing lesion touching both the SVZ and Ctx was excluded because it was difficult to determine whether it originated from the SVZ or Ctx. Contrast-enhancing lesions touching the SVZ but not the Ctx had significantly worse overall survival than non-SVZ lesions (441 days vs. 897 days, P = .002). GBM touching only the Ctx had a better prognosis (901 days vs. 473 days, P &lt; .001) than non-Ctx lesions and was associated with EGFR alteration (39.4% vs. 13.2%, P = .015). Multiple contrast lesions were predominant in PDGFRA alteration and RB1-wild type (P = .036 and P = .031, respectively).

Conclusions
EGFR alteration was associated with cortical lesions. And PDGFRA alteration correlated with multiple lesions. Our results suggest that clarifying the association between driver genes and tumor localization may be useful in clinical practice, including prognosis prediction.
Pectate lyase-like lubricates the male gametophyte's path toward its mating partner
Authors: Chebli Youssef , Geitmann Anja 
Published: September 2023

Abstract
The pollen tube is an extension of the male gametophyte in plants and mediates sexual reproduction by delivering the sperm cells to the female gametophyte. To accomplish this task, the elongating pollen tube must break through the thick wall of the pollen grain and penetrate multiple pistillar tissues. Both processes require the loosening of cell wall material—that of the pollen intine and that of the apoplast of the transmitting tract. The enzymatic toolbox for these cell wall modifying processes employed by the invading male gametophyte is elusive. We investigated the role of the pectin-digesting pectate lyase-like (PLL) by combining mutant analysis with microscopy observations, fluorescence recovery after photo-bleaching experiments, and immuno-detection. We show that in Arabidopsis (Arabidopsis thaliana), PLLs are required for intine loosening during the first steps of pollen tube germination. We provide evidence that during pollen tube elongation, PLLs are released by the pollen tube into the extracellular space, suggesting that they may be employed to soften the apoplast of the transmitting tissue. The synergistic enzymatic action of PLLs in the pollen grain, the pollen tube, and the transmitting track contribute to an effective fertilization process.
Arabidopsis ACYL CARRIER PROTEIN4 and RHOMBOID LIKE10 act independently in chloroplast phosphatidate synthesis
Authors: Xu Yang , Kambhampati Shrikaar , Morley Stewart A , Cook Ron , Froehlich John , Allen Doug K , Benning Christoph 
Published: September 2023

Abstract
ACYL CARRIER PROTEIN4 (ACP4) is the most abundant ACP isoform in Arabidopsis (Arabidopsis thaliana) leaves and acts as a scaffold for de novo fatty acid biosynthesis and as a substrate for acyl-ACP-utilizing enzymes. Recently, ACP4 was found to interact with a protein-designated plastid RHOMBOID LIKE10 (RBL10) that affects chloroplast monogalactosyldiacylglycerol (MGDG) biosynthesis, but the cellular function of this interaction remains to be explored. Here, we generated and characterized acp4 rbl10 double mutants to explore whether ACP4 and RBL10 directly interact in influencing chloroplast lipid metabolism. Alterations in the content and molecular species of chloroplast lipids such as MGDG and phosphatidylglycerol were observed in the acp4 and rbl10 mutants, which are likely associated with the changes in the size and profiles of diacylglycerol (DAG), phosphatidic acid (PA), and acyl-ACP precursor pools. ACP4 contributed to the size and profile of the acyl-ACP pool and interacted with acyl-ACP-utilizing enzymes, as expected for its role in fatty acid biosynthesis and chloroplast lipid assembly. RBL10 appeared to be involved in the conversion of PA to DAG precursors for MGDG biosynthesis as evidenced by the increased 34:x PA and decreased 34:x DAG in the rbl10 mutant and the slow turnover of radiolabeled PA in isolated chloroplasts fed with [14C] acetate. Interestingly, the impaired PA turnover in rbl10 was partially reversed in the acp4 rbl10 double mutant. Collectively, this study shows that ACP4 and RBL10 affect chloroplast lipid biosynthesis by modulating substrate precursor pools and appear to act independently.
Engineering Candida boidinii formate dehydrogenase for activity with the non-canonical cofactor 3′-NADP(H)
Authors: Vainstein Salomon , Banta Scott 
Published: September 2023

Abstract
Oxidoreductases catalyze essential redox reactions, and many require a diffusible cofactor for electron transport, such as NAD(H). Non-canonical cofactor analogs have been explored as a means to create enzymatic reactions that operate orthogonally to existing metabolism. Here, we aimed to engineer the formate dehydrogenase from Candid boidinii (CbFDH) for activity with the non-canonical cofactor nicotinamide adenine dinucleotide 3′-phosphate (3′-NADP(H)). We used PyRosetta, the Cofactor Specificity Reversal Structural Analysis and Library Design (CSR-SALAD), and structure-guided saturation mutagenesis to identify mutations that enable CbFDH to use 3′-NADP+. Two single mutants, D195A and D195G, had the highest activities with 3′-NADP+, while the double mutant D195G/Y196S exhibited the highest cofactor selectivity reversal behavior. Steady state kinetic analyses were performed; the D195A mutant exhibited the highest KTS value with 3′-NADP+. This work compares the utility of computational approaches for cofactor specificity engineering while demonstrating the engineering of an important enzyme for novel non-canonical cofactor selectivity.
Post–COVID-19 Intensive Care Unit-Acquired Weakness Compromises Long-Term Functional Status
Authors: Schmidt Débora , Margarites Ane Glauce , Alvarenga Letícia Pinto Krás Borges , Paesi Priscilla Moliterni , Friedman Gilberto , Sbruzzi Graciele 
Published: September 2023

Abstract

Objective
The objective of this study was to evaluate the impact of intensive care unit (ICU)-acquired weakness (ICUAW) on the functional independence of patients hospitalized for coronavirus disease 2019 (COVID-19) over 6 months after ICU discharge.

Methods
This was a prospective cohort study that included patients who were admitted to the ICU because of COVID-19 and who were monitored for 6 months after discharge from the ICU via telephone. Patients were evaluated at 3 times (30 days, 3 months, and 6 months after discharge from the ICU) for functional independence for personal care and mobility activities (Barthel Scale), independence for self-care (Katz Index), impact of COVID-19 on functional status (post–COVID-19 Functional Status Scale [PCFS]), and mobility level (ICU Mobility Scale). The existence of some degree of dependence was considered when the Barthel Scale score was &lt;100 points, the Katz Index was ≥1, and the PCFS score was ≥1. A PCFS score of ≥3 indicated moderate or severe dependence. Patients with a Medical Research Council score of &lt;48 at discharge from the ICU were diagnosed with ICUAW.

Results
Sixty-eight patients were included, with a mean age of 51 (SD = 13) years. The ICUAW rate at ICU discharge was 35%. In the evaluation with the PCFS, the values for the presence of any functional limitation at 30 days, 3 months, and 6 months after ICU discharge were 89.7%, 57.4%, and 38.2%, respectively. The rate of persistence of functional limitations after 6 months was higher in patients with ICUAW than in those without ICUAW (66.7% vs 22.8%; P = .000); the same was true for moderate or severe limitations (20.8% vs 4.5%; P = .035). Likewise, functional independence for personal care, mobility, and self-care activities was poorer in patients with ICUAW.

Conclusions
In patients surviving an ICU stay due to COVID-19, decreased functional independence persists even 6 months after discharge, and patients with ICUAW have worse outcomes.

Impact
Patients who survive ICU stays due to COVID-19 continue to have greater functional dependence even 6 months after ICU discharge.