bluuebunny/crossref_metadata_2025 huggingface dataset:
COVID-19 Pandemic: Mental Health in Girls With and Without Fragile X Syndrome
Authors: Jordan Tracy L , Bartholomay Kristi L , Lee Cindy Hsin-Yu , Miller Jonas G , Lightbody Amy A , Reiss Allan L
Published: September 2021

Objective

Children and adolescents, who have less developed coping skills, are affected by natural disasters and other traumatic events differently than adults. Emotional and behavioral effects are particularly pronounced during a pandemic-related disaster, when support networks that typically promote healthy coping, such as friends, teachers, and family members, may be less available. Children and adolescents with fragile X syndrome (FXS), who are at increased risk for developing anxiety and depression, may be particularly vulnerable to behavioral or emotional difficulties during a pandemic. This study examined the mental health outcomes of school-aged girls with FXS during the COVID-19 pandemic and associated stay-at-home orders.

Methods

Participants included 47 school-aged girls with FXS and 33 age- and developmentally matched comparison girls. Associations between COVID-19 behavioral and emotional outcomes and prior academic, adaptive, behavioral, and emotional functioning as well as prior maternal mental health and characteristics of the mother–child relationship were examined. Qualitative data from the parental report of emotional and behavioral responses to the pandemic were also obtained.

Results

Results indicate that school-aged girls with FXS demonstrate a distinct profile of COVID-19 related associations compared to the comparison group, such that pandemic-related worries and emotional impact of pandemic restrictions were predicted by prior mental health factors for the comparison group but by prior social, behavioral, and relational factors for the FXS group.

Conclusions

Findings provide insight into factors that may confer risk or resilience for youth with special needs, suggesting potential therapeutic targets and informing public health initiatives in response to the pandemic.
Storm Clouds and Silver Linings: Day-to-Day Life in COVID-19 Lockdown and Emotional Health in Adolescent Girls
Authors: Silk Jennifer S , Scott Lori N , Hutchinson Emily A , Lu Celine , Sequeira Stefanie L , McKone Kirsten M P , Do Quyen B , Ladouceur Cecile D
Published: September 2021

Objective

We examined risk and protective factors for emotional health problems in adolescent girls during the COVID-19 pandemic. We investigated pre- to early-pandemic changes in symptoms of anxiety and depression, documented daily activities and perceived positive and negative impacts of the pandemic, and linked perceived positive and negative impacts of the pandemic to real-time changes in emotional health.

Methods

The study was a 10-day daily diary study with 93 U.S. adolescent girls (aged 12–17; 68% White non-Hispanic) at temperamental risk for anxiety and depression, conducted in April/May 2020 when all participants were under state-issued stay-at-home orders. Girls provided daily reports of positive and negative affect, depressive and anxious symptoms, activities, and positive and negative impacts resulting from the pandemic.

Results

Girls reported engaging in many activities that may contribute to well-being. Mixed effects analyses revealed positive impacts associated with improved same-day emotional health such as more time for family and relaxation and reduced pressure from school/activities. Negative impacts associated with poorer same-day emotional health included problems with online schooling, lack of space/privacy, lack of a regular schedule, and family conflict.

Conclusion

Findings highlight the importance of providing in-person or quality online schooling, resources and space for learning, promoting daily routines, and spending time with teens while reducing family conflict. The pandemic also appears to have offered many girls a respite from the chronic stress of modern teen life, with time to relax and engage in creative and healthy pursuits showing benefits for daily emotional health, which should be considered following the return to normal life.
Parents’ Experiences of Their Child’s Solid-Organ Transplant: A Meta-Ethnography of Qualitative Studies
Authors: McLoughlin Affraic , Wilson Charlotte , Swords Lorraine
Published: September 2021

Objective

The aim of this paper was to conduct a systematic review and meta-ethnography of qualitative studies examining the experiences of parents adjusting to life after the solid organ transplant (SOT) of their child.

Methods

A systematic review of the literature was conducted to identify qualitative studies that examined this topic. The search retrieved 4,964 studies to review against inclusion criteria. A total of 21 studies were included in the meta-ethnography. A reciprocal translation was conducted to compare themes identified in each study. A line of argument synthesis was then conducted in order to integrate the similarities and differences between all of the studies into a new interpretative context.

Results

The synthesis identified four themes: (a) adjusting to life after transplant, (b) factors that facilitate adjustment, (c) factors that disrupt adjustment, and (d) changes caused by transplant. As a result of the synthesis, a new interpretation of parents’ experiences of adjusting to life after the SOT of their child was constructed. A summary figure is presented.

Conclusion

This review found that while parents may struggle to adapt to life post-transplant and the demands of caring for their child, the experience can also result in the development of new skills, a new appreciation for life, and viewing the self in a more positive manner. A better understanding of parental experiences will promote the development of more effective interventions for the adjustment of parents and families to post-transplant life.
Beliefs About Worry and Pain Amongst Adolescents With and Without Chronic Pain
Authors: Wainwright Elaine , Jordan Abbie , Fisher Emma , Wilson Charlotte , Mullen Darragh , Madhavakkannan Harini
Published: September 2021

Objective

To explore beliefs about worries, beliefs about pain, and worries about pain held by adolescents with and without chronic pain.

Methods

Adolescents with and without chronic pain aged 14–19 completed an online survey with free text questions about pain and worry. We collected demographics and used the Penn State Worry Questionnaire and Pain Catastrophizing Scale for Children to contextualize the qualitative data, which was analyzed with reflexive thematic analysis.

Results

Eighty-one participants completed the survey, 36 with chronic pain and 45 without (mean age: 16.73). Compared to adolescents without chronic pain, adolescents living with chronic pain reported significantly higher general worry and pain catastrophizing. Thematic analysis generated two themes, “Worry changes perceptions of selfhood” and “Pain changes perceptions of selfhood.” Each theme comprised two sub-themes showing how current and future identity trajectories were distorted by worry and pain. The theme “Pain changes perceptions of selfhood” also included a third sub-theme: “Pain impedes future working choices.” Worry content as well as process was problematic in all adolescents. Adolescents experiencing chronic pain had specific, additional worries that pain reduces future career progression. These worries appeared highly salient and challenging.

Conclusions

Adolescents may need greater support in recognizing worry as part of normative development. Adolescents in pain may benefit from specific support identifying and reducing how pain-related worries interact with their futures and careers, and from school-based and vocational interventions to reduce the realistic risks they face negotiating modern labor markets.
Clinical Influenza Testing Practices in Hospitalized Children at United States Medical Centers, 2015-2018
Authors: Tenforde Mark W , Campbell Angela P , Michaels Marian G , Harrison Christopher J , Klein Eileen J , Englund Janet A , Selvarangan Rangaraj , Halasa Natasha B , Stewart Laura S , Weinberg Geoffrey A , Williams John V , Szilagyi Peter G , Staat Mary A , Boom Julie A , Sahni Leila C , Singer Monica N , Azimi Parvin H , Zimmerman Richard K , McNeal Monica M , Talbot H Keipp , Monto Arnold S , Martin Emily T , Gaglani Manjusha , Silveira Fernanda P , Middleton Donald B , Ferdinands Jill M , Rolfes Melissa A
Published: September 2021

At nine US hospitals that enrolled children hospitalized with acute respiratory illness (ARI) during 2015-2016 through 2017-2018 influenza seasons, 50% of children with ARI received clinician-initiated testing for influenza and 35% of cases went undiagnosed due to lack of clinician-initiated testing. Marked heterogeneity in testing practice was observed across sites.
The use of soft contact lens for intraocular foreign body removal to avoid inadvertent cataract formation
Authors: Eid Maroun , Bou Said Reeda , Jarade Elias
Published: September 2021

Ocular injuries carry a significant morbidity worldwide. Visual outcomes vary depending on the mechanism of injury, the damage on arrival and the surgical technique used. The presence of an intraocular foreign body further complicates matters, due to its constituents, the infectious potential, and/or damage to intraocular structures. Another described problem is the inadvertent cataract formation due to contact with the natural lens during removal of the foreign body. The purpose of this paper is to describe a case with a mechanical foreign body lodging in the posterior chamber without harming the lens. The surgical challenge was to remove it without causing cataractous changes. Therefore, a soft contact lens was used to form a protective layer between the foreign body and the natural lens of the eye allowing successful removal of the foreign body.
Endoscopic and surgical management of Bouveret’s syndrome complicated by gallstone ileus
Authors: Varre Jaya Sai , Wu Jin Ling , Hopmann Peter , Ruiz Oscar , Reddy Raghuram
Published: September 2021

Bouveret’s syndrome is a rare complication that occurs most commonly in elderly patients with multiple comorbidities. It is secondary to an impacted gallstone causing gastric outlet obstruction from a cholecystoduodenal fistula, and there is no defined standardized management in current literature. A 92-year-old woman presents to our tertiary community hospital with abdominal discomfort concerning for bowel obstruction. Computed tomography revealed pneumobilia with a cholecystoduodenal fistula and a large gallstone in the proximal duodenum causing gastric outlet obstruction. The impacted gallstone failed endoscopic extraction with electrohydraulic lithotripsy, and patient subsequently developed distal gallstone ileus requiring exploratory laparotomy and enterolithotomy. This case report examines the need for early coordinated endoscopic and surgical management of a patient with Bouveret’s syndrome complicated by gallstone ileus as it is associated with high morbidity and mortality rates.
Mixed serous and mucinous retroperitoneal cystadenoma: an extremely rare case
Authors: Khan Hotak Mirwais , He Mike
Published: September 2021

Mixed serous and mucinous retroperitoneal cyst adenoma is an extremely rare condition as most of the reported cases in the literature are primary retroperitoneal mucinous cystadenomas and primary retroperitoneal serous cystadenomas. They are initially asymptomatic and become symptomatic gradually depending on their size and anatomical extension and location. We report a 49-year-old woman with a history of right-side abdomen pain for a few years. Diagnostic images revealed a large retroperitoneal cystic lesion. A laparoscopic resection was performed without spillage. The patient was discharged without complication postoperatively and no recurrence on follow-up. Surgical excision, either open/or laparoscopic without any spillage, remains the most effective and appropriate treatment for this lesion.
Primary pancreatic cancer of the jejunum: a case report and brief review of literature
Authors: Brigmon Erika P , Malik Mishel S , Malik Shazli N , Logue Alicia
Published: September 2021

The variable clinical presentation of heterotopic pancreatic (HP) tissue and its malignant transformation makes the diagnosis very challenging. These lesions are very rare, usually not suspected upon initial presentation and for the most part, are diagnosed incidentally on review of pathology following surgical resection. In this study, we are reporting an adenocarcinoma arising from jejunal heterotopic pancreatic tissue in a 59-year-old female and a brief review of previously reported cases.
The Etymology of Sabaic brṯ‘place’
Authors: Rendsburg Gary A
Published: September 2021

This article proposes an etymology for the common Sabaic word brṯ ‘place’, namely, via derivation from the nominalised prepositional phrase b‘in’ + ʾṯ r ‘place’, with two phonological shifts at play: (a) elision of the intervocalic glottal stop, and (b) metathesis of /ṯ / and /r/.
Reflections on the Suffix Conjugations in Semitic
Authors: Loesov Sergey
Published: September 2021

Suffix conjugations (SCs) of East and West Semitic may not be traced back to the same verb form in Proto-Semitic. Rather, they evolved separately, by way of a ‘common drift’ in the two branches of Semitic. This is demonstrated, in particular, by a crass contrast, both in forms and diathetic meanings, between the SCs of East and West Semitic. Due to the scarcity of data, a gapless reconstruction of diachronic paths for neither of the two branches is possible. Only one thing remains certain: both the SC in East Semitic and non-passive forms of the SC in Central Semitic ultimately came about via verbalisation of adjectives, first primary and then deverbal ones.
Dynamics and thermal sensitivity of rRNA maturation paths in plants
Authors: Shanmugam Thiruvenkadam , Streit Deniz , Schroll Frank , Kovacevic Jelena , Schleiff Enrico
Published: September 2021

Ribosome biogenesis is a constitutive fundamental process for cellular function. Its rate of production depends on the rate of maturation of precursor rRNA (pre-rRNA). The rRNA maturation paths are characterized by four dominant rate-limiting intermediates with cell type variation of the processivity rate. We have identified that high temperature stress in plants, while halting the existing pre-rRNA maturation schemes, also transiently triggers an atypical pathway for 35S pre-rRNA processing. This pathway leads to production of an aberrant pre-rRNA, reminiscent of yeast 24S, encompassing 18S and 5.8S rRNAs that do not normally co-occur together at subunit levels; this response is elicited specifically by high and not low temperatures. We show this response to be conserved in two other model crop plant species (rice and tomato). This pathway persists even after returning to normal growth conditions for 1 h, and is reset between 1 h and 6 h after stress treatment, probably due to resumption of normal 35S pre-rRNA synthesis and processing. The heat-induced ITS2 cleavage-derived precursors and stalled P-A2-like precursors were heterogeneous in nature, with a fraction containing polymeric (A) tails. Furthermore, high temperature treatment and subsequent fractionation resulted in polysome and pre-rRNA depletion.
Portal Venous Thrombosis in a Special Operations Paratrooper: A Case Report
Authors: Bridwell Rachel E , Clerkin Sean , Walker Nathaniel R , Long Brit , Goss Sarah
Published: September 2021

Portal vein thrombosis is the thrombotic occlusion of the extrahepatic portal system, which can propagate towards the vena caval system. Although rare, it occurs primarily in those with cirrhosis, intra-abdominal infections, malignancy, or hypercoagulable disorders. This report describes the first reported case of a soldier within special operations without identifiable risk factors who was found to have a completely occlusive portal vein thrombosis after approximately 10 days of insidious abdominal pain. This case emphasizes the importance of considering this rare but dangerous pathology among this highly screened and capable special operations population.
A systematic review on distribution and antifungal resistance pattern ofCandidaspecies in the Indian population
Authors: Verma Rashi , Pradhan Dibyabhaba , Hasan Ziaul , Singh Harpreet , Jain Arun Kumar , Khan Luqman Ahmad
Published: September 2021

The emergence of antifungal drug resistance in Candida species has led to increased morbidity and mortality in immunocompromised patients. Understanding species distribution and antifungal drug resistance patterns is an essential step for novel drug development. A systematic review was performed addressing this challenge in India with keywords inclusive of ‘Candida’, ‘Antifungal Drug Resistance’, ‘Candidemia’, ‘Candidiasis’ and ‘India’. A total of 106 studies (January 1978–March 2020) from 20 Indian states were included. Of over 11,429 isolates, Candida albicans was the major species accounting for 37.95% of total isolates followed by C. tropicalis (29.40%), C. glabrata (11.68%) and C. parapsilosis (8.36%). Rates of antifungal resistance were highest in non-albicans Candida (NAC) species - C. haemuloni (47.16%), C. krusei (28.99%), C. lipolytica (28.89%) and C. glabrata (20.69%). Approximately 10.34% isolates of C. albicans were observed to be drug resistant. Candida species were frequently resistant to certain azoles (ketoconazole-22.2%, miconazole–22.1% and fluconazole–21.8%). In conclusion, the present systematic review illustrates the overall distribution and antifungal resistance pattern of Candida species among the Indian population that could be helpful in the future for the formation of treatment recommendations for the region but also elsewhere.

Lay Summary

A total of 106 studies were reviewed to define the prevalence, distribution and antifungal resistance pattern of Candida species in India. The presented data could become the point of reference for all reported findings on Candida species in India.
Characterizing mass, momentum, energy, and metal outflow rates of multiphase galactic winds in the FIRE-2 cosmological simulations
Authors: Pandya Viraj , Fielding Drummond B , Anglés-Alcázar Daniel , Somerville Rachel S , Bryan Greg L , Hayward Christopher C , Stern Jonathan , Kim Chang-Goo , Quataert Eliot , Forbes John C , Faucher-Giguère Claude-André , Feldmann Robert , Hafen Zachary , Hopkins Philip F , Kereš Dušan , Murray Norman , Wetzel Andrew
Published: September 2021

We characterize mass, momentum, energy, and metal outflow rates of multiphase galactic winds in a suite of FIRE-2 cosmological ‘zoom-in’ simulations from the Feedback in Realistic Environments (FIRE) project. We analyse simulations of low-mass dwarfs, intermediate-mass dwarfs, Milky Way-mass haloes, and high-redshift massive haloes. Consistent with previous work, we find that dwarfs eject about 100 times more gas from their interstellar medium (ISM) than they form in stars, while this mass ‘loading factor’ drops below one in massive galaxies. Most of the mass is carried by the hot phase (>105 K) in massive haloes and the warm phase (103−105 K) in dwarfs; cold outflows (<103 K) are negligible except in high-redshift dwarfs. Energy, momentum, and metal loading factors from the ISM are of order unity in dwarfs and significantly lower in more massive haloes. Hot outflows have 2−5 × higher specific energy than needed to escape from the gravitational potential of dwarf haloes; indeed, in dwarfs, the mass, momentum, and metal outflow rates increase with radius whereas energy is roughly conserved, indicating swept up halo gas. Burst-averaged mass loading factors tend to be larger during more powerful star formation episodes and when the inner halo is not virialized, but we see effectively no trend with the dense ISM gas fraction. We discuss how our results can guide future controlled numerical experiments that aim to elucidate the key parameters governing galactic winds and the resulting associated preventative feedback.
Stellar migration and chemical enrichment in the milky way disc: a hybrid model
Authors: Johnson James W , Weinberg David H , Vincenzo Fiorenzo , Bird Jonathan C , Loebman Sarah R , Brooks Alyson M , Quinn Thomas R , Christensen Charlotte R , Griffith Emily J
Published: September 2021

We develop a hybrid model of galactic chemical evolution that combines a multiring computation of chemical enrichment with a prescription for stellar migration and the vertical distribution of stellar populations informed by a cosmological hydrodynamic disc galaxy simulation. Our fiducial model adopts empirically motivated forms of the star formation law and star formation history, with a gradient in outflow mass loading tuned to reproduce the observed metallicity gradient. With this approach, the model reproduces many of the striking qualitative features of the Milky Way disc’s abundance structure: (i) the dependence of the [O/Fe]–[Fe/H] distribution on radius Rgal and mid-plane distance |z|; (ii) the changing shapes of the [O/H] and [Fe/H] distributions with Rgal and |z|; (iii) a broad distribution of [O/Fe] at sub-solar metallicity and changes in the [O/Fe] distribution with Rgal, |z|, and [Fe/H]; (iv) a tight correlation between [O/Fe] and stellar age for [O/Fe] > 0.1; (v) a population of young and intermediate-age α-enhanced stars caused by migration-induced variability in the Type Ia supernova rate; (vi) non-monotonic age–[O/H] and age–[Fe/H] relations, with large scatter and a median age of ∼4 Gyr near solar metallicity. Observationally motivated models with an enhanced star formation rate ∼2 Gyr ago improve agreement with the observed age–[Fe/H] and age–[O/H] relations, but worsen agreement with the observed age–[O/Fe] relation. None of our models predict an [O/Fe] distribution with the distinct bimodality seen in the observations, suggesting that more dramatic evolutionary pathways are required. All code and tables used for our models are publicly available through the Versatile Integrator for Chemical Evolution (VICE; https://pypi.org/project/vice).
1/f noise analysis for FAST H i intensity mapping drift-scan experiment
Authors: Hu Wenkai , Li Yichao , Wang Yougang , Wu Fengquan , Zhang Bo , Zhu Ming , Zuo Shifan , Lagache Guilaine , Ma Yin-Zhe , Santos Mario G , Chen Xuelei
Published: September 2021

We investigate the 1/f noise of the Five-hundred-meter Aperture Spherical Telescope (FAST) receiver system using drift-scan data from an intensity mapping pilot survey. All the 19 beams have 1/f fluctuations with similar structures. Both the temporal and the 2D power spectrum densities are estimated. The correlations directly seen in the time series data at low frequency f are associated with the sky signal, perhaps due to a coupling between the foreground and the system response. We use singular value decomposition (SVD) to subtract the foreground. By removing the strongest components, the measured 1/f noise power can be reduced significantly. With 20 modes subtraction, the knee frequency of the 1/f noise in a 10-MHz band is reduced to $1.8 \times 10^{-3}\, {\rm Hz}$, well below the thermal noise over 500-s time-scale. The 2D power spectra show that the 1/f-type variations are restricted to a small region in the time-frequency space and the correlations in frequency can be suppressed with SVD modes subtraction. The residual 1/f noise after the SVD mode subtraction is uncorrelated in frequency, and a simple noise diode frequency-independent calibration of the receiver gain at 8-s interval does not affect the results. The 1/f noise can be important for H i intensity mapping, we estimate that the 1/f noise has a knee frequency (fk) ∼ 6 × 10−4 Hz, and time and frequency correlation spectral indices (α) ∼ 0.65, (β) ∼ 0.8 after the SVD subtraction of 30 modes. This can bias the H i power spectrum measurement by 10 per cent.
Gravitational-wave cosmology with extreme mass-ratio inspirals
Authors: Laghi Danny , Tamanini Nicola , Del Pozzo Walter , Sesana Alberto , Gair Jonathan , Babak Stanislav , Izquierdo-Villalba David
Published: September 2021

The Laser Interferometer Space Antenna (LISA) will open the mHz frequency window of the gravitational-wave (GW) landscape. Among all the new GW sources expected to emit in this frequency band, extreme mass-ratio inspirals (EMRIs) constitute a unique laboratory for astrophysics and fundamental physics. Here, we show that EMRIs can also be used to extract relevant cosmological information, complementary to both electromagnetic (EM) and other GW observations. By using the loudest EMRIs (S/N > 100) detected by LISA as dark standard sirens, statistically matching their sky localization region with mock galaxy catalogues, we find that constraints on H0 can reach ∼1.1 per cent (∼3.6 per cent) accuracy, at the 90 per cent credible level, in our best(worst)- case scenario. By considering a dynamical dark energy (DE) cosmological model, with ΛCDM parameters fixed by other observations, we further show that in our best(worst)- case scenario ∼5.9 per cent (∼12.3 per cent) relative uncertainties at the 90 per cent credible level can be obtained on w0, the DE equation of state parameter. Besides being relevant in their own right, EMRI measurements will be affected by different systematics compared to both EM and ground-based GW observations. Cross-validation with complementary cosmological measurements will therefore be of paramount importance, especially if convincing evidence of physics beyond ΛCDM emerges from future observations.
CLMM: a LSST-DESC cluster weak lensing mass modeling library for cosmology
Authors: Aguena M , Avestruz C , Combet C , Fu S , Herbonnet R , Malz A I , Penna-Lima M , Ricci M , Vitenti S D P , Baumont L , Fan H , Fong M , Ho M , Kirby M , Payerne C , Boutigny D , Lee B , Liu B , McClintock T , Miyatake H , Sifón C , von der Linden A , Wu H , Yoon M ,   The LSST Dark Energy Science Collaboration, Chisari Elisa , Clowe Douglas , Dell’Antonio Ian
Published: September 2021

We present the v1.0 release of CLMM, an open source python library for the estimation of the weak lensing masses of clusters of galaxies. CLMM is designed as a stand-alone toolkit of building blocks to enable end-to-end analysis pipeline validation for upcoming cluster cosmology analyses such as the ones that will be performed by the Vera C. Rubin Legacy Survey of Space and Time-Dark Energy Science Collaboration (LSST-DESC). Its purpose is to serve as a flexible, easy-to-install, and easy-to-use interface for both weak lensing simulators and observers and can be applied to real and mock data to study the systematics affecting weak lensing mass reconstruction. At the core of CLMM are routines to model the weak lensing shear signal given the underlying mass distribution of galaxy clusters and a set of data operations to prepare the corresponding data vectors. The theoretical predictions rely on existing software, used as backends in the code, that have been thoroughly tested and cross-checked. Combined theoretical predictions and data can be used to constrain the mass distribution of galaxy clusters as demonstrated in a suite of example Jupyter Notebooks shipped with the software and also available in the extensive online documentation.
Spurious heating of stellar motions in simulated galactic discs by dark matter halo particles
Authors: Ludlow Aaron D , Fall S Michael , Schaye Joop , Obreschkow Danail
Published: September 2021

We use idealized N-body simulations of equilibrium stellar discs embedded within course-grained dark matter (DM) haloes to study the effects of spurious collisional heating on disc structure and kinematics. Collisional heating artificially increases the vertical and radial velocity dispersions of disc stars, as well as the thickness and size of discs; the effects are felt at all galacto-centric radii. The integrated effects of collisional heating are determined by the mass of DM halo particles (or equivalently, by the number of particles at fixed halo mass), their local density and characteristic velocity dispersion, but are largely insensitive to the stellar particle mass. The effects can therefore be reduced by increasing the mass resolution of DM in cosmological simulations, with limited benefits from increasing the baryonic (or stellar) mass resolution. We provide a simple empirical model that accurately captures the effects of spurious collisional heating on the structure and kinematics of simulated discs, and use it to assess the importance of disc heating for simulations of galaxy formation. We find that the majority of state-of-the-art zoom simulations, and a few of the highest-resolution, smallest-volume cosmological runs, are in principle able to resolve thin stellar discs in Milky Way-mass haloes, but most large-volume cosmological simulations cannot. For example, DM haloes resolved with fewer than ≈106 particles will collisionally heat stars near the stellar half-mass radius such that their vertical velocity dispersion increases by ≳ 10 per cent of the halo’s virial velocity in approximately one Hubble time.
A radiation transfer model for the Milky Way. II The global properties and large scale structure
Authors: Natale Giovanni , Popescu Cristina C , Rushton Mark , Yang Ruizhi , Thirlwall Jordan J , Pricopi Dumitru
Published: September 2021

We obtained an axi-symmetric model for the large-scale distribution of stars and dust in the Milky Way (MW) using a radiative transfer code that can account for the existing near-infrared (NIR)/mid-infrared/submm all-sky emission maps of our Galaxy. We find that the MW has a star-formation rate of SFR = 1.25 ± 0.2 M⊙/yr, a stellar mass M* = (4.9 ± 0.3) × 1010 M⊙, and a specific SFR that is relatively constant with radius (except for the inner 1 kpc). We identified an inner radius Rin = 4.5 kpc beyond which the stellar emissivity and dust distribution fall exponentially. For R < Rin the emissivities fall linearly towards the centre. The old stellar populations in the disk have an exponential scalelength that increases monotonically from $h_{\rm s}^{\rm disk}(K)=2.2\pm 0.6$ kpc in the NIR, to $h_{\rm s}^{\rm disk}(B)=3.2\pm 0.9$ kpc at the shorter optical bands, and a scaleheight that varies with radial distance, from $z_{\rm s}^{\rm disk}(0) =140\pm 20$ pc in the centre to $z_{\rm s}^{\rm disk}(R_{\odot }) =300\pm 20$ pc at the solar radius. The young stellar populations have a scalelength of $h_{\rm s}^{\rm tdisk}=3.2\pm 0.9$ kpc and a scaleheight that varies from $z_{\rm s}^{\rm tdisk}(0)=50\pm 10$ pc in the centre to $z_{\rm s}^{\rm tdisk}(R_{\odot })=90\pm 10$ pc at the solar radius. We discovered an inner stellar disk within the central 4.5 kpc, which we associate with the extended long bar of the MW. Most of the obscured star formation happens within this inner thin disk. The diffuse dust is mainly distributed in a disk with scalelength $h_{\rm d}^{\rm disk}=5.2\pm 0.8$ kpc and scaleheight $z_{\rm d}^{\rm disk}=0.14\pm 0.02$ kpc. We give the first derivation of the MW attenuation curve and present it as a functional fit to the model data. We find the MW to lie in the Green Valley of the main sequence relation for spiral galaxies.
The influence of the environment on the spin evolution of low-mass stars – I. External photoevaporation of circumstellar discs
Authors: Roquette J , Matt S P , Winter A J , Amard L , Stasevic S
Published: September 2021

Massive stars are strong sources of far-ultraviolet radiation that can be hostile to the evolution of protoplanetary discs, driving mass-loss by external photoevaporation and shortening disc-dissipation time-scales. Their effect may also reduce the time-scale of angular momentum exchanges between the disc and host star during the early pre-main-sequence phase. To improve our understanding of the environmental influence on the rotational history of stars, we developed a model that considers the influence of the local far-ultraviolet radiation on the spin evolution of low mass stars. Our model includes an assumption of disc locking, which fixes the rotation rate during the star-disc-interaction phase, with the duration of this phase parametrized as a function of the local far-ultraviolet radiation and stellar mass (in the range of 0.1–1.3 M⊙). In this way, we demonstrate how the feedback from massive stars can significantly influence the spin evolution of stars and explain the mass dependence observed in period-mass distributions of young regions like Upper Sco and NGC 2264. The high far-ultraviolet environments of high-mass stars can skew the period distribution of surrounding stars towards fast-rotation, explaining the excess of fast-rotating stars in the open cluster h Per. The proposed link between rotation and the pre-main-sequence environment opens new avenues for interpreting the rotational distributions of young stars. For example, we suggest that stellar rotation may be used as a tracer for the primordial ultraviolet irradiation for stars up to ∼1 Gyr, which offers a potential method to connect mature planetary systems to their birth environment.
Distant probes of rotation measure structure: where is the Faraday rotation towards the Magellanic Leading Arm?
Authors: Jung S Lyla , McClure-Griffiths N M , Hill Alex S
Published: September 2021

Faraday rotation measures (RMs) should be interpreted with caution because there could be multiple magneto-ionized medium components that contribute to the net Faraday rotation along sightlines. We introduce a simple test using Galactic diffuse polarized emission that evaluates whether structures evident in RM observations are associated with distant circumgalactic medium or foreground interstellar medium. We focus on the Magellanic Leading Arm region where a clear excess of RM was previously reported. There are two gaseous objects standing out in this direction: the distant Magellanic Leading Arm and the nearby Antlia supernova remnant (SNR). We recognized narrow depolarized filaments in the $2.3\, \rm GHz$ S-band Polarization All Sky Survey image that overlaps with the reported RM excess. We suggest that there is a steep gradient in Faraday rotation in a foreground screen arising from the Antlia SNR. The estimated strength of the line-of-sight component of the magnetic field is $B_{\parallel }\sim 5\, \rm \mu G$, assuming that the excess of RM is entirely an outcome of the magnetized supernova shell. Our analysis indicates that the overlap between the RM excess and the Magellanic Leading Arm is only a remarkable coincidence. We suggest for future RM grid studies that checking Galactic diffuse polarization maps is a convenient way to identify local Faraday screens.
Broadened profiles of diffuse interstellar bands
Authors: Krełowski J , Galazutdinov G A , Gnaciński P , Hakalla R , Szajna W , Siebenmorgen R
Published: September 2021

The paper describes profile broadening and peak wavelength variation of diffuse interstellar bands (DIBs) measured for 46 lines of sight, probably caused by the physical properties of intervening clouds. The full width at half-maximum of four studied DIBs (5780, 5797, 6196 and 6614 Å) demonstrates strong variability, sometimes doubling the widths of the features. Despite the high magnitude of the effect, our current analysis is restricted to the strongest DIBs because the weaker ones require a much higher signal-to-noise ratio. The profile broadening in the studied DIBs moves the profile’s centres towards longer wavelengths, probably due to the excitation of higher levels of the P branch of the unknown molecular carrier. Moreover, DIBs are broader in clouds with abundantly populated vibrationally excited states of hydrogen molecules; that is, the broadening of DIBs correlates with the rotational temperature estimated on the H2ν= 2 vibrational level. However, objects that demonstrate extremely broadened profiles of DIBs are scarce. The extreme peculiarity of the DIB profiles was detected in Herschel 36. Here we show the gradual growths of the widths of DIBs, confirmed in spectra from different instruments.
The Thousand-Pulsar-Array programme on MeerKAT – VI. Pulse widths of a large and diverse sample of radio pulsars
Authors: Posselt B , Karastergiou A , Johnston S , Parthasarathy A , Keith M J , Oswald L S , Song X , Weltevrede P , Barr E D , Buchner S , Geyer M , Kramer M , Reardon D J , Serylak M , Shannon R M , Spiewak R , Venkatraman Krishnan V
Published: September 2021

We present pulse width measurements for a sample of radio pulsars observed with the MeerKAT telescope as part of the Thousand-Pulsar-Array (TPA) programme in the MeerTime project. For a centre frequency of 1284 MHz, we obtain 762 W10 measurements across the total bandwidth of 775 MHz, where W10 is the width at the 10 per cent level of the pulse peak. We also measure about 400 W10 values in each of the four or eight frequency sub-bands. Assuming, the width is a function of the rotation period P, this relationship can be described with a power law with power law index μ = −0.29 ± 0.03. However, using orthogonal distance regression, we determine a steeper power law with μ = −0.63 ± 0.06. A density plot of the period-width data reveals such a fit to align well with the contours of highest density. Building on a previous population synthesis model, we obtain population-based estimates of the obliquity of the magnetic axis with respect to the rotation axis for our pulsars. Investigating the width changes over frequency, we unambiguously identify a group of pulsars that have width broadening at higher frequencies. The measured width changes show a monotonic behaviour with frequency for the whole TPA pulsar population, whether the pulses are becoming narrower or broader with increasing frequency. We exclude a sensitivity bias, scattering and noticeable differences in the pulse component numbers as explanations for these width changes, and attempt an explanation using a qualitative model of five contributing Gaussian pulse components with flux density spectra that depend on their rotational phase.
Impact of magnetic braking on high-mass close binary formation
Authors: Harada Naoto , Hirano Shingo , Machida Masahiro N , Hosokawa Takashi
Published: September 2021

Combining numerical simulations and analytical modelling, we investigate whether close binary systems form by the effect of magnetic braking. Using magnetohydrodynamics simulations, we calculate the cloud evolution with a sink, for which we do not resolve the binary system or binary orbital motion to realize long-term time integration. Then, we analytically estimate the binary separation using the accreted mass and angular momentum obtained from the simulation. In unmagnetized clouds, wide binary systems with separations of >100 au form, in which the binary separation continues to increase during the main accretion phase. In contrast, close binary systems with separations of <100 au can form in magnetized clouds. Since the efficiency of magnetic braking strongly depends on both the strength and configuration of the magnetic field, they also affect the formation conditions of a close binary. In addition, the protostellar outflow has a negative impact on close binary formation, especially when the rotation axis of the prestellar cloud is aligned with the global magnetic field. The outflow interrupts the accretion of gas with small angular momentum, which is expelled from the cloud, while gas with large angular momentum preferentially falls from the side of the outflow on to the binary system and widens the binary separation. This study shows that a cloud with a magnetic field that is not parallel to the rotation axis is a favourable environment for the formation of close binary systems.
Strobed imaging as a method for the determination and diagnosis of local seeing
Authors: Stubbs Christopher W
Published: September 2021

The image quality budget of many telescopes can have substantial contributions from local seeing, both ‘mirror’ and ‘dome’, which arise from turbulence and temperature variations that are difficult to quantify, measure directly, and ameliorate. We describe a method to determine the ‘local’ seeing degradation due to wavefront perturbations within the final few metres of the optical path from celestial sources to the focal plane of a ground-based telescope, using the primary instrument and along the same path taken by light from celestial sources. The concept involves placing strobed emitters along the light path to produce images on the main focal plane that ‘freeze’ different realizations of index perturbations. This method has the advantage of measuring directly the image motion and scintillation imparted by the dynamic spatial and temporal structure of local perturbations in the index of refraction along the light path, with a clean separation from seeing induced in the atmosphere above the dome. The strobed-source approach allows for rapid image motion and scintillation to be measured directly on the focal plane, even for large-aperture telescopes with wide-field instruments and slow shutters, such as that being constructed for the Rubin Observatory. A conceptual design is presented that uses the ‘guider’ CCDs in the Rubin telescope focal plane to make local-seeing measurements on demand, perhaps even during science exposures.
Unraveling circular polarimetric images of magnetically arrested accretion flows near event horizon of a black hole
Authors: Mościbrodzka M , Janiuk A , De Laurentis M
Published: September 2021

Magnetically arrested accretion flows are thought to fuel some of the supermassive black holes and to power their relativistic jets. We calculate and study a time sequence of linear and circular polarimetric images of numerical, high resolution, and long-duration simulations of magnetically dominated flows to investigate observational signatures of strong magnetic fields near the event horizon of a non-rotating black hole. We find that the magnitude of resolved linear and circular polarizations is rather sensitive to the assumption of the coupling of electron and ions in the accretion flow. Models with cooler electrons have higher Faraday rotation and conversion depths, which result in scrambled linear polarization and enhanced circular polarization. In those high Faraday thickness cases, the circular polarization is particularly sensitive to dynamics of toroidasl-radial magnetic fields in the accretion flows. The models with high Faraday thickness are characterized by nearly constant handedness of circular polarization, consistent with observations of some accreting black holes. We also find that the emission region produced by light, which is lensed around the black hole, shows inversion of circular polarization handedness with respect to the handedness of the circular polarization of the entire emission region. Such polarity inversions are unique to near horizon emission.
Projecting the likely importance of weak-interaction-driven bulk viscosity in neutron star mergers
Authors: Most Elias R , Harris Steven P , Plumberg Christopher , Alford Mark G , Noronha Jorge , Noronha-Hostler Jacquelyn , Pretorius Frans , Witek Helvi , Yunes Nicolás
Published: September 2021

In this work, we estimate how much bulk viscosity driven by Urca processes is likely to affect the gravitational wave signal of a neutron star coalescence. In the late inspiral, we show that bulk viscosity affects the binding energy at fourth post-Newtonian order. Even though this effect is enhanced by the square of the gravitational compactness, the coefficient of bulk viscosity is likely too small to lead to observable effects in the waveform during the late inspiral, when only considering the orbital motion itself. In the post-merger, however, the characteristic time-scales and spatial scales are different, potentially leading to the opposite conclusion. We post-process data from a state-of-the-art equal-mass binary neutron star merger simulation to estimate the effects of bulk viscosity (which was not included in the simulation itself). In that scenario, we find that bulk viscosity can reach high values in regions of the merger. We compute several estimates of how much it might directly affect the global dynamics of the considered merger scenario, and find that it could become significant. Even larger effects could arise in different merger scenarios or in simulations that include non-linear effects. This assessment is reinforced by a quantitative comparison with relativistic heavy-ion collisions where such effects have been explored extensively.
Dust traffic jams in inclined circumbinary protoplanetary discs – I. Morphology and formation theory
Authors: Aly Hossam , Gonzalez Jean-François , Nealon Rebecca , Longarini Cristiano , Lodato Giuseppe , Price Daniel J
Published: September 2021

Gas and dust in inclined orbits around binaries experience precession induced by the binary gravitational torque. The difference in precession between gas and dust alters the radial drift of weakly coupled dust and leads to density enhancements where the radial drift is minimized. We explore this phenomenon using 3D hydrodynamical simulations to investigate the prominence of these ‘dust traffic jams’ and the evolution of the resulting dust sub-structures at different disc inclinations and binary eccentricities. We then derive evolution equations for the angular momentum of warped dust discs and implement them in a 1D code and present calculations to further explain these traffic jams. We find that dust traffic jams in inclined circumbinary discs provide significant dust density enhancements that are long lived and can have important consequences for planetesimal formation.
CHANG-ES XXIII: influence of a galactic wind in NGC 5775
Authors: Heald G H , Heesen V , Sridhar S S , Beck R , Bomans D J , Brüggen M , Chyży K T , Damas-Segovia A , Dettmar R-J , English J , Henriksen R , Ideguchi S , Irwin J , Krause M , Li J-T , Murphy E J , Nikiel-Wroczyński B , Piotrowska J , Rand R J , Shimwell T , Stein Y , Vargas C J , Wang Q D , van Weeren R J , Wiegert T
Published: September 2021

We present new radio continuum images of the edge-on starburst galaxy NGC 5775, from LOFAR (140 MHz) and the Karl G. Jansky Very Large Array CHANG-ES survey (1500 MHz). We trace the non-thermal radio halo up to 13 kpc from the disc, measuring the non-thermal spectral index and estimating the total equipartition magnetic field strength (≈13 $\mu$G in the disc and ≈7 $\mu$G above the plane). The radio halo has a similar extent at both frequencies, displays evidence for localized cosmic ray streaming coinciding with prominent H α filaments and vertical extensions of the regular magnetic field, and exhibits a boxy morphology especially at 140 MHz. In order to understand the nature of the disc–halo flow, we extend our previous model of cosmic ray propagation by implementing an iso-thermal wind with a tunable ‘flux tube’ (approximately hyperboloidal) geometry. This updated model is successful in matching the vertical distribution of non-thermal radio emission, and the vertical steepening of the associated spectral index, in a consistent conceptual framework with few free parameters. Our new model provides the opportunity to estimate the mass outflow driven by the star formation process, and we find an implied rate of $\dot{M}\approx 3$–$6\, \mathrm{M_{\odot }\, yr^{-1}}$ (≈40–80 per cent of the star formation rate) if the escape velocity is reached, with substantial uncertainty arising from the poorly understood distribution of interstellar medium material entrained in the vertical flow. The wind may play a role in influencing the vertical gradient in rotational velocity.