bluuebunny/crossref_metadata_2025 huggingface dataset:
Hospitalisations for falls and hip fractures attributable to vitamin D deficiency in older Australians
Authors: Neale Rachel E. , Wilson Louise F. , Black Lucinda J. , Waterhouse Mary , Lucas Robyn M. , Gordon Louisa G.
Published: January 2021

Vitamin D deficiency is associated with an increased risk of falls and fractures. Assuming this association is causal, we aimed to identify the number and proportion of hospitalisations for falls and hip fractures attributable to vitamin D deficiency (25 hydroxy D (25(OH)D) <50 nmol/l) in Australians aged ≥65 years. We used 25(OH)D data from the 2011/12 Australian Health Survey and relative risks from published meta-analyses to calculate population-attributable fractions for falls and hip fracture. We applied these to data published by the Australian Institute of Health and Welfare to calculate the number of events each year attributable to vitamin D deficiency. In men and women combined, 8·3 % of hospitalisations for falls (7991 events) and almost 8 % of hospitalisations for hip fractures (1315 events) were attributable to vitamin D deficiency. These findings suggest that, even in a sunny country such as Australia, vitamin D deficiency contributes to a considerable number of hospitalisations as a consequence of falls and for treatment of hip fracture in older Australians; in countries where the prevalence of vitamin D deficiency is higher, the impact will be even greater. It is important to mitigate vitamin D deficiency, but whether this should occur through supplementation or increased sun exposure needs consideration of the benefits, harms, practicalities and costs of both approaches.
The foreign language effect in bilingualism: Examining prosocial sentiment after offense taking
Authors: Miller David , Solis-Barroso Cecilia , Delgado Rodrigo
Published: January 2021

This study examines whether theforeign language effectmitigates reactions to value-inconsistent sociopolitical content. We examined 69 English–Spanish bilinguals and 31 Spanish–English heritage bilinguals, half of whom did the experiment in their native language and half in their second language. Participants were administered a survey in which trial emotiveness was manipulated by using the quantifiers some and all (e.g.,Some Trump supporters are racistsvs.All Trump supporters are racists). The some-types (n= 30) served as a baseline for the all-types (n= 30). After each target, participants rated their willingness to be prosocial (e.g., holding the door for a stranger) on a scale of 1–7, 1 beingtotally agreeand 7 beingtotally disagree. Our results suggest that processing emotional information in a second language is less emotional than in a first language and that such a decrease in emotionality results in the neutralization of offense taken. However, individual differences in linguistic profiles across participants, as well as contextual framing, lead to discrete value judgments. Proficiency, learner type, political affiliation, and context type affect willingness to engage in prosocial behavior. As a group, the bilinguals showed no decrease in their willingness to engage in such behaviors, regardless of context type; speakers of higher proficiency and stronger political values increase prosocial sentiment; and lower proficiency and weaker views lead to neutral prosocial sentiment.
Reconnecting to others: grounded theory of social functioning following age-related hearing loss
Authors: Fowler Elizabeth , Woodside Jayne V. , Kee Frank , Loughrey David , Lawlor Brian , McHugh Power Joanna
Published: January 2021

Age-related hearing loss (ARHL) is common and a known risk factor for social disengagement in later life. This study explored social functioning following a diagnosis of ARHL. Using a constructivist grounded theory approach we developed an interview schedule to advance a grounded theory from data collected from six older adults who used either hearing aids or cochlear implants. Interview questions concerned social functioning as well as focusing on their perspective of the impact of ARHL on cognitive functioning. We describe a grounded theory conceived as ‘Reconnecting to Others’. This theory posits that participants faced social challenges in relation to their ARHL, and resolved these challenges partly through the use of hearing aids and cochlear implantation. The theory also emphasises the importance of help from other hearing aid users for new users, and corroborates prior findings about strategies older adults with ARHL use to cope with their hearing impairment in various social situations. Once hearing aids and cochlear implants are used and adapted to with the help of peers, participants completed their journey by helping others who had received diagnoses of ARHL. Additionally, participants spoke of the pleasure of hearing again. Interestingly, no participant felt that their ARHL had impacted their cognitive functioning. Our theory provides a basis for explaining existing quantitative findings as well as creating new hypotheses for future testing.
Determinants of Managed Entry Agreements in the context of Health Technology Assessment: a comparative analysis of oncology therapies in four countries
Authors: Efthymiadou Olina , Kanavos Panos
Published: January 2021

Background

Managed Entry Agreements (MEAs) are increasingly used to address uncertainties arising in the Health Technology Assessment (HTA) process due to immature evidence of new, high-cost medicines on their real-world performance and cost-effectiveness. The literature remains inconclusive on the HTA decision-making factors that influence the utilization of MEAs. We aimed to assess if the uptake of MEAs differs between countries and if so, to understand which HTA decision-making criteria play a role in determining such differences.

Methods

All oncology medicines approved since 2009 in Australia, England, Scotland, and Sweden were studied. Four categories of variables were collected from publicly available HTA reports of the above drugs: (i) Social Value Judgments (SVJs), (ii) Clinical/Economic evidence submitted, (iii) Interpretation of this evidence, and (iv) Funding decision. Conditional/restricted decisions were coded as Listed With Conditions (LWC) other than an MEA or LWC including an MEA (LWCMEA). Cohen's κ-scores measured the inter-rater agreement of countries on their LWCMEA outcomes and Pearson's chi-squared tests explored the association between HTA variables and LWCMEA outcomes.

Results

A total of 74 drug-indication pairs were found resulting in n = 296 observations; 8 percent (n = 23) were LWC and 55 percent (n = 163) were LWCMEA. A poor-to-moderate agreement existed between countries (−.29 < κ < .33) on LWCMEA decisions. Cross-country differences within the LWCMEA sample were partly driven by economic uncertainties and largely driven by SVJs considered across agencies.

Conclusions

A set of HTA-related variables driving the uptake of MEAs across countries was identified. These findings can be useful in future research aimed at informing country-specific, “best-practice” guidelines for successful MEA implementation.
Epidemiology of COVID-19 in Northern Ireland, 26 February 2020–26 April 2020
Authors: Pett J. , McAleavey P. , McGurnaghan P. , Spiers R. , O'Doherty M. , Patterson L. , Johnston J.
Published: January 2021

This paper describes the epidemiology of coronavirus disease 2019 (COVID-19) in Northern Ireland (NI) between 26 February 2020 and 26 April 2020, and analyses enhanced surveillance and contact tracing data collected between 26 February 2020 and 13 March 2020 to estimate secondary attack rates (SAR) and relative risk of infection among different categories of contacts of individuals with laboratory confirmed severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Our results show that during the study period COVID-19 cumulative incidence and mortality was lower in NI than the rest of the UK. Incidence and mortality were also lower than in the Republic of Ireland (ROI), although these observed differences are difficult to interpret given considerable differences in testing and surveillance between the two nations. SAR among household contacts was 15.9% (95% CI 6.6%–30.1%), over 6 times higher than the SAR among ‘high-risk’ contacts at 2.5% (95% CI 0.9%–5.4%). The results from logistic regression analysis of testing data on contacts of laboratory-confirmed cases show that household contacts had 11.0 times higher odds (aOR: 11.0, 95% CI 1.7–70.03,P-value: 0.011) of testing positive for SARS-CoV-2 compared to other categories of contacts. These results demonstrate the importance of the household as a locus of SARS-CoV-2 transmission, and the urgency of identifying effective interventions to reduce household transmission.
Not by equations alone: Reasoning with extensible effects
Authors: KISELYOV OLEG , MU SHIN-CHENG , SABRY AMR
Published: January 2021

The challenge of reasoning about programs with (multiple) effects such as mutation, jumps, or IO dates back to the inception of program semantics in the works of Strachey and Landin. Using monads to represent individual effects and the associated equational laws to reason about them proved exceptionally effective. Even then it is not always clear what laws are to be associated with a monad—for a good reason, as we show for non-determinism. Combining expressions using different effects brings challenges not just for monads, which do not compose, but also for equational reasoning: the interaction of effects may invalidate their individual laws, as well as induce emerging properties that are not apparent in the semantics of individual effects. Overall, the problems are judging the adequacy of a law; determining if or when a law continues to hold upon addition of new effects; and obtaining and easily verifying emergent laws.

We present a solution relying on the framework of (algebraic, extensible) effects, which already proved itself for writing programs with multiple effects. Equipped with a fairly conventional denotational semantics, this framework turns useful, as we demonstrate, also for reasoning about and optimizing programs with multiple interacting effects. Unlike the conventional approach, equational laws are not imposed on programs/effect handlers, but induced from them: our starting point hence is a program (model), whose denotational semantics, besides being used directly, suggests and justifies equational laws and clarifies side conditions. The main technical result is the introduction of the notion of equivalence modulo handlers (“modulo observation”) or a particular combination of handlers—and proving it to be a congruence. It is hence usable for reasoning in any context, not just evaluation contexts—provided particular conditions are met.

Concretely, we describe several realistic handlers for non-determinism and elucidate their laws (some of which hold in the presence of any other effect). We demonstrate appropriate equational laws of non-determinism in the presence of global state, which have been a challenge to state and prove before.
Triposes as a generalization of localic geometric morphisms
Authors: Frey Jonas , Streicher Thomas
Published: January 2021

In Hyland et al. (1980), Hyland, Johnstone and Pitts introduced the notion of tripos for the purpose of organizing the construction of realizability toposes in a way that generalizes the construction of localic toposes from complete Heyting algebras. In Pitts (2002), one finds a generalization of this notion eliminating an unnecessary assumption of Hyland et al. (1980). The aim of this paper is to characterize triposes over a base topos ${\cal S}$ in terms of so-called constant objects functors from ${\cal S}$ to some elementary topos. Our characterization is slightly different from the one in Pitts’s PhD Thesis (Pitts, 1981) and motivated by the fibered view of geometric morphisms as described in Streicher (2020). In particular, we discuss the question whether triposes over Set giving rise to equivalent toposes are already equivalent as triposes.
Search for high-redshift blazars with Fermi-LAT
Authors: Kreter Michael
Published: January 2021

Abstarct

High-redshift blazars (z ⩾ 2.5) are one of the most powerful classes of gamma-ray sources in the Universe. These objects posses the highest jet powers and luminosities and have black-hole masses often in excess of 109 solar masses. In addition, high-redshift blazars are important cosmological probes and serve as test objects for blazar evolution models. Due to their large distance, their high-energy emission peak is downshifted to energies below the GeV range, which makes them difficult to study with Fermi/LAT and only the very brightest objects are detectable. Hence, only a small number of high-redshift blazars could be detected with Fermi/LAT so far. In this work, we present a strategy to significantly increase the detection statistics at redshift z ⩾ 2.5 via a search for flaring events in high-redshift gamma-ray blazars whose long-term flux remains below the sensitivity limit of Fermi/LAT. Seven previously GeV undetected high-redshift blazars have been identified from their bright monthly outburst periods, while more detections are expected in the future.
Panchromatic characterisation of accreting black holes in dusty star-forming galaxies
Authors: Rivera Gabriela Calistro
Published: January 2021

Although AGN do not typically dominate the bolometric emission of dusty star forming galaxies, large AGN fractions (sometimes > 40%) have been observed in various sub-millimeter surveys. These diagnostics have been however mostly based on X-ray counterpart selections and a complete multiwavength census of the fraction of AGN hosts is needed. I will present new advances in the modelling of panchromatic spectral energy distributions (SEDs) of active galactic nuclei (AGN), based on our publicly available code AGNfitter (Calistro-Rivera et al.2016). AGNfitter implements a fully Bayesian Markov Chain Monte Carlo method to fit the spectral energy distributions of AGNs pushing the wavelengths frontiers from the radio to the X-rays. I will present a recent application of AGNfitter on dusty star forming galaxies in the ALESS submillimeter survey to obtain an unbiased multiwavelength characterisation of the nuclear activity buried in dusty star formation. Our method reveals a significantly larger contribution of AGN activity to the emission in these galaxies than previously observed based on X-rays diagnostics. Our method represents a unique tool to potentially characterise an unbiased accretion history of the Universe when applied to larger populations of star-forming galaxies.
AGN types and unification model
Authors: Spinoglio Luigi , Fernández-Ontiveros Juan Antonio
Published: January 2021

The motivation of the “unified model” is to explain the main properties of the large zoo of active galactic nuclei with a single physical object. The discovery of broad permitted lines in the polarized spectrum of type 2 Seyfert galaxies in the mid 80’s led to the idea of an obscuring torus, whose orientation with respect to our line of sight was the reason of the different optical spectra. However, after many years of observations with different techniques, including IR and mm interferometry, the resulting properties of the observed dust structures differ from the torus model that would be needed to explain the type 1 vs type 2 dichotomy. Moreover, in the last years, multi-frequency monitoring of active galactic nuclei has shown an increasing number of transitions from one type to the other one, which cannot be explained in terms of the simple orientation of the dusty structure surrounding the active galactic nucleus (AGN). The interrelations between the AGN and the host galaxy, as also shown in the Magorrian relation, suggest that the evolution of the host galaxy may also have an important role in the observed manifestation of the nuclei. As an example, the observed delay between the maximum star formation activity and the onset of the AGN activity, and the higher occurrence of type 2 nuclei in star forming galaxies, have suggested the possible evolutionary path from, e.g., H II → AGN2 → AGN1. In the next years the models of unification need to also consider this observational framework and not only simple orientation effects.
Predicting the emission profile and estimation of model parameters for some nearby LLAGN using accretion and jet models
Authors: Bandyopadhyay Bidisha , Xie Fu-Guo , Nagar Neil M. , Schleicher Dominik R. G. , Ramakrishnan Venkatessh , Arévalo Patricia , López Elena , Diaz Yaherlyn
Published: January 2021

The Event Horizon Telescope (EHT) provides a unique opportunity to probe the physics of supermassive black holes through Very Large Baseline Interferometry (VLBI), such as the existence of the event horizon, the accretion processes as well as jet formation in Low Luminosity AGN (LLAGN). We build a theoretical model which includes an Advection Dominated Accretion Flow (ADAF) and a simple radio jet outflow. The predicted spectral energy distribution (SED) of this model can be compared to observations to get the best estimates of the model parameters. The model-predicted radial emission profiles at different frequency bands can be used to predict whether the inflow can be resolved by the EHT or other telescopes. We have applied this method to some nearby LLAGN such as M84, NGC 4594, NGC 4278 and NGC 3998. We also estimate the model parameters for each of them using high resolution data from different surveys.
The role of failed accretion disk winds in active galactic nuclei
Authors: Giustini Margherita , Proga Daniel
Published: January 2021

Both observational and theoretical evidence point at outflows originating from accretion disks as fundamental ingredients of active galactic nuclei (AGN). These outflows can have more than one component, for example an unbound supersonic wind and a failed wind (FW). The latter is a prediction of the simulations of radiation-driven disk outflows which show that the former is accompanied by an inner failed component, where the flow struggles to escape from the strong gravitational pull of the supermassive black hole. This FW component could provide a physical framework to interpret various phenomenological components of AGN. Here we briefly discuss a few of them: the broad line region, the X-ray obscurer, and the X-ray corona.
Elusive accretion discs in low luminosity AGN
Authors: Almudena Prieto M. , Fernandez-Ontiveros Juan A.
Published: January 2021

Low luminosity AGN represent the vast majority of the AGN population in the near universe, and still the least conforming class with the standard AGN scenario. Their low luminosity is at odds with their often very high black hole masses and powerful jets. I will review the challenges that parsec-scale observations across the electromagnetic spectrum of some of the nearest ones are opening on the true nature of their emission, their transition from the most luminous to the feeble ones, and their accretion power. The strict limits imposed by these observations on their accretion power are confronted with the high mechanical energy inferred for their jets. Possible scenarios for these nuclei including the extraction of power form the black hole spin are discussed (Prieto et al. 2016; Fernandez-Ontiveros et al. 2019).
Properties of green valley galaxies in relation to their selection criteria
Authors: Nyiransengiyumva Beatrice , Pović Mirjana , Nkundabakura Pheneas , Mahoro Antoine
Published: January 2021

The distribution of galaxies has been studied to show the difference between the blue cloud and red sequence and to define the green valley region. However, there are still many open questions regarding the importance of the green valley for understanding the morphological transformation and evolution of galaxies, how galaxies change from late-type to early-type and the role of AGN in galaxy formation and evolution scenario. The work focused on studying in more details the properties of green valley galaxies by testing the six most used selection criteria, differences between them, and how they may affect the main results and conclusions. The main findings are that, by selecting the green valley galaxies using different criteria, we are selecting different types of galaxies in terms of their stellar masses, sSFR, SFR, spectroscopic classification and morphological properties, where the difference was more significant for colour criteria than for sSFR and SFR vs. M* criteria.
Quasar host galaxies and environments in the GAMA survey
Authors: Kotilainen Jari
Published: January 2021

We present first results from our study of the host galaxies and environments of quasars in Galaxy And Mass Assembly (GAMA), a multiwavelength photometric and spectroscopic survey for ∼300,000 galaxies over ∼300 deg2, to a limiting magnitude of r ∼ 20 mag. We use a GAIA-selected sample of ∼350 quasars at z < 0.3 in GAMA. For all the quasars, we determine all surrounding GAMA galaxies and measure their star formation (SF) rate and SF history, and the host galaxy morphology and group membership of the quasars. As a comparison sample of inactive galaxies, we use 1000 subsets of galaxies in GAMA, matched in redshift and galaxy stellar mass to the quasars. We find that quasar activity does not depend on the large-scale environment (cluster/group/void), although quasars tend to prefer satellite location in their environment. Compared to inactive galaxies, quasars are preferentially hosted in bulge-dominated galaxies and have higher SF rates, both overall and averaged over the last 10 and 100 Myr. Quasars also have shorter median SF timescales, shorter median time since the last SF burst, and higher metallicity than inactive galaxies. We discuss these results in terms of triggering mechanisms of the quasar activity and the role of quasars in galaxy evolution.
The impact of AGN on the life of their host galaxies at z ∼ 2
Authors: Circosta Chiara
Published: January 2021

Feedback from active galactic nuclei (AGN) is thought to be key in shaping the life cycle of host galaxies by regulating star formation. Therefore, measuring the molecular gas reservoir out of which stars form is essential to understand the impact of AGN on star formation. In this talk I present an ongoing analysis to study the CO(J = 3−2) emission in a sample of 25 AGN at z ∼ 2 using ALMA observations. The CO properties of our AGN have been compared to normal (non-AGN) star-forming galaxies. The comparison between the two samples reveals that, on average, the CO luminosities of AGN at high stellar masses (log(M*/M⊙) > 11) are 0.5 dex lower than normal galaxies. We ascribe this difference to the AGN activity, which could be able to change the conditions of the gas through, e.g., excitation, heating or removal of CO.
Accretion and star formation in ‘radio-quiet’ quasars
Authors: White Sarah V. , Jarvis Matt J. , Kalfountzou Eleni , Hardcastle Martin J. , Verma Aprajita , Cao Orjales José M. , Stevens Jason
Published: January 2021

Radio observations allow us to identify a wide range of active galactic nuclei (AGN), which play a significant role in the evolution of galaxies. Amongst AGN at low radio-luminosities is the ‘radio-quiet’ quasar (RQQ) population, but how they contribute to the total radio emission is under debate, with previous studies arguing that it is predominantly through star formation. In this talk, SVW summarised the results of recent papers on RQQs, including the use of far-infrared data to disentangle the radio emission from the AGN and that from star formation. This provides evidence that black-hole accretion, instead, dominates the radio emission in RQQs. In addition, we find that this accretion-related emission is correlated with the optical luminosity of the quasar, whilst a weaker luminosity-dependence is evident for the radio emission connected with star formation. What remains unclear is the process by which this accretion-related emission is produced. Understanding this for RQQs will then allow us to investigate how this type of AGN influences its surroundings. Such studies have important implications for modelling AGN feedback, and for determining the accretion and star-formation histories of the Universe.
Clustering dependence of Chandra COSMOS Legacy AGN on host galaxy properties
Authors: Allevato Viola
Published: January 2021

The presence of a super massive BH in almost all galaxies in the Universe is an accepted paradigm in astronomy. How these BHs form and how they co-evolve with the host galaxy is one of the most intriguing unanswered problems in modern Cosmology and of extreme relevance to understand the issue of galaxy formation. Clustering measurements can powerfully test theoretical model predictions of BH triggering scenarios and put constraints on the typical environment where AGN live in, through the connection with their host dark matter halos. In this talk, I will present some recent results on the AGN clustering dependence on host galaxy properties, such as galaxy stellar mass, star formation rate and specific BH accretion rate, based on X-ray selected Chandra COSMOS Legacy Type 2 AGN. We found no significant AGN clustering dependence on galaxy stellar mass and specif BHAR for Type 2 COSMOS AGN at mean z ∼ 1.1, with a stellar - halo mass relation flatter than predicted for non active galaxies in the Mstar range probed by our sample. We also observed a negative clustering dependence on SFR, with AGN hosting halo mass increasing with decreasing SFR. Mock catalogs of active galaxies in hosting dark matter halos with logMh[Msun] > 12.5, matched to have the same X-ray luminosity, stellar mass and BHAR of COSMOS AGN predict the observed Mstar - Mh, BHAR - Mh and SFR-Mh relations, at z ∼ 1.
Radio jets: Properties, life and impact
Authors: Morganti Raffaella
Published: January 2021

Our view of the properties of extragalactic radio jets and the impact they have on the host galaxy has expanded in the recent years. This has been possible thanks to the data from new or upgraded radio telescopes. This review briefly summarises the current status of the field and describes some of the exciting recent results and the surprises they have brought. In particular, the physical properties of radio jets as function of their radio power will be discussed together with the advance made in understanding the life-cycle of radio sources. The evolutionary stage (e.g. newly born, dying, restarted) of the radio AGN can be derived from their morphology and properties of the radio spectra. The possibilities offered by the new generation of low-frequency radio telescopes make it possible to derive (at least to first order) the time-scale spent in each phase. The presence of a cycle of activity ensures a recurrent impact of the radio jets on their surrounding inter-stellar and inter-galactic medium and, therefore, their relevance for AGN feedback. The last part is dedicated to the recent results showing the effect of jets on the surrounding galactic medium. The predictions made by numerical simulations on the impact of a radio jet (and in particular a newly born jet) on a clumpy medium describe well what is seen by the observations. The high resolution studies of jet-driven outflows of cold gas (and molecular) has provided new important addition both in term of quantifying the impact of the outflows and their relevance for feedback as well as for providing an unexpected view of the physical conditions of the gas under these extreme conditions.
Understanding the origin of radio outflows in Seyfert galaxies using radio polarimetry
Authors: Sebastian Biny , Kharb Preeti , O’ Dea Christopher P. , Gallimore Jack F. , Baum Stefi A. , Colbert Edward J. M.
Published: January 2021

The role of starburst winds versus active galactic nuclei (AGN) jets/winds in the formation of the kiloparsec scale radio emission seen in Seyferts is not yet well understood. In order to be able to disentangle the role of various components, we have observed a sample of Seyfert galaxies exhibiting kpc-scale radio emission suggesting outflows, along with a comparison sample of starburst galaxies, with the EVLA B-array in polarimetric mode at 1.4 GHz and 5 GHz. The Seyfert galaxy NGC 2639, shows highly polarized secondary radio lobes, not observed before, which are aligned perpendicular to the known pair of radio lobes. The additional pair of lobes represent an older epoch of emission. A multi-epoch multi-frequency study of the starburst-Seyfert composite galaxy NGC 3079, reveals that the jet together with the starburst superwind and the galactic magnetic fields might be responsible for the well-known 8-shaped radio lobes observed in this galaxy. We find that many of the Seyfert galaxies in our sample show bubble-shaped lobes, which are absent in the starburst galaxies that do not host an AGN.
The space VLBI mission RadioAstron: AGN results
Authors: Kovalev Yuri
Published: January 2021

The RadioAstron Space VLBI mission utilized the 10-m radio telescope on board the dedicated Spektr-R spacecraft to observe cosmic radio sources with an unprecedented angular resolution at centimeter wave lengths in total and polarized light. The longest baseline of the space-ground interferometer is about 350000 km. It operated in 2011–2019 together with 58 largest ground radio telescopes. Resolution as high as 10 microarcsec has been achieved. An overview of its AGN science results will be presented in the talk. It includes a probe of jet emission mechanism through brightness temperature measurements, reconstruction of magnetic field structure close to the jet origin using polarization data, jet formation and collimation study for well resolved nearby AGN, as well as observations and analysis of jet precession and plasma instabilities. We will also discuss a new scattering effect which was discovered by RadioAstron to affect high resolution radio measurements of AGN and SgrA*.
Optical variations in changing-look AGNs selected at X-rays
Authors: Cazzoli Sara , Masegosa Josefa , Márquez Isabel , Hernández-García Lorena , Álvarez-Hernández A. , Hermosa-Muñoz Laura
Published: January 2021

Recent observations of local AGNs have revealed that many of them show a ‘changing look’ behavior at optical and X-rays wavelengths in the sense of transiting between different AGNs families (e.g. from type-1 to type-2 or vice-versa). In order to pinpoint the possible relation of the changes, we performed optical spectroscopic observations (with CAFOS/CAHA) of 15 changing look AGNs selected at X-rays. Highlights from our spectroscopic study are presented.
NGC7469 as seen by MEGARA at the GTC
Authors: Cazzoli Sara , Gil de Paz Armando , Márquez Isabel , Masegosa Josefa , Iglesias Jorge , Gallego Jesus , Carrasco Esperanza , Cedazo Raquel , Luisa García-Vargas María , Castillo-Morales África , Pascual Sergio , Cardiel Nicolás , Pérez-Calpena Ana , Gómez-Alvarez Pedro , Martínez-Delgado Ismael , Hermosa-Muñoz Laura
Published: January 2021

We present the main results from the analysis of the Hα-[NII] emission lines with integral field spectroscopy observations gathered with MEGARA at the GTC of the nearby Seyfert 1.5 galaxy NGC7469. We obtained maps of the ionised gas in the inner 12.5 arcsec × 11.3 arcsec, at spatial scales of 0.62 arcsec, with an unprecedented spectral resolution (R ˜ 20 000). We characterized the kinematics and ionisation mechanism of the distinct kinematic components (Cazzoli et al.2019).
Optical spectral properties of radio loud quasars along the main sequence
Authors: del Olmo Ascensión , Marziani Paola , Ganci Valerio , D’Onofrio Mauro , Bon Edi , Bon Natasa , Negrete Alenka C.
Published: January 2021

We analyze the optical properties of Radio-Loud quasars along the Main Sequence (MS) of quasars. A sample of 355 quasars selected on the basis of radio detection was obtained by cross-matching the FIRST survey at 20cm and the SDSS DR12 spectroscopic survey. We consider the nature of powerful emission at the high-Fe ii end of the MS. At variance with the classical radio-loud sources which are located in the Population B domain of the MS optical plane, we found evidence indicating a thermal origin of the radio emission of the highly accreting quasars of Population A.
Accretion rate in AGN and X-ray-to-optical flux ratio at z ≤ 0.2
Authors: Gaulle Asrate , Pović Mirjana , Zewdie Dejene
Published: January 2021

We explored a sample of 545 local galaxies using data from the 3XMM-DR7 and SDSS-DR8 surveys. We carried out all analyses up to z ˜ 0.2, and we studied the relation between X/O flux ratio and accretion rate for different classes of active galaxies such as LINERs and Seyfert 2. We obtained a slight correlation between the two parameters if the whole sample of AGN is used. However, LINERs and Sy2 galaxies show different properties, slight correlation and slight anti-correlation, respectively. This could confirm that LINERs and Sy2 galaxies have different accretion efficiencies and maybe different accretion disc properties, as has been suggested previously.
A search for new γ-ray blazars from infrared selected candidates
Authors: Musiimenta Blessing , Sversut Arsioli Bruno , Jurua Edward , Mutabazi Tom
Published: January 2021

We present a systematic study of gamma-ray blazar candidates based on a sample of 40 objects taken from the WIBR catalogue. By using a likelihood analysis, 26 of the 40 sources showed significant gamma-ray signatures ⩾ 3σ. Using high-energy test statistics (TS) maps, we confirm 8 sources, which are completely new, and show another 15 promising γ-ray candidates. The results from this analysis show that a multi-frequency approach can help to improve the current description of the gamma-ray sky.
Feii strength in NLS1s – dependence on the viewing angle and FWHM(Hβ)
Authors: Panda Swayamtrupta , Marziani Paola , Czerny Bożena
Published: January 2021

We address the effect of orientation of the accretion disk plane and the geometry of the broad line region (BLR) in the context of understanding the distribution of quasars along their Main Sequence. We utilize the photoionization code CLOUDY to model the BLR, incorporating the ‘un-constant’ virial factor. We show the preliminary results of the analysis to highlight the co-dependence of the Eigenvector 1 parameter, RFeII on the broad HβFWHM (i.e. the line dispersion) and the inclination angle (θ), assuming fixed values for the Eddington ratio (Lbol/ LEdd), black hole mass (MBH), spectral energy distribution (SED) shape, cloud density (nH) and composition.†
Understanding galaxy mergers and AGN feedback with UVIT
Authors: Rubinur Khatun , Das Mousumi , Kharb Preeti , Rahne P. T.
Published: January 2021

Simulations expect an enhanced star-formation and active galactic nuclei (AGN) activity during galaxy mergers, which can lead to formation of binary/dual AGN. AGN feedback can enhance or suppress star-formation. We have carried out a pilot study of a sample of ˜10 dual nuclei galaxies with AstroSat’s Ultraviolet Imaging Telescope (UVIT). Here, we present the initial results for two sample galaxies (Mrk 739, ESO 509) and deep multi-wavelength data of another galaxy (Mrk 212). UVIT observations have revealed signatures of positive AGN feedback in Mrk 739 and Mrk 212, and negative feedback in ESO 509. Deeper UVIT observations have recently been approved; these will provide better constraints on star-formation as well as AGN feedback in these systems.
Extragalactic background light inhomogeneities and Lorentz-Invariance Violation in gamma-gamma absorption and Compton scattering
Authors: Abdalla Hassan
Published: January 2021

At energies approaching the Planck energy scale 1019GeV, several quantum-gravity theories predict that familiar concepts such as Lorentz (LIV) symmetry can be broken. Such extreme energies are currently unreachable by experiments on Earth, but for photons traveling over cosmological distances the accumulated deviations from the Lorentz symmetry may be measurable using the Cherenkov Telescope Array (CTA). To study the spectral hardening feature observed in some VHE gamma-ray blazars, we calculate the reduction of the EBL gamma-gamma opacity due to the existence of underdense regions along the line of sight to VHE -gamma ray sources and we compared with the possibility of a LIV signature. Considering the LIV effect, we found that the cosmic opacity for VHE-gamma rays with energy more than 10 TeV can be strongly reduced. I will further discuss the impact of LIV on the Compton scattering process, and how future CTA observations may open an exciting window on studies of the fundamental physics.
Mass-radius relation of compact objects
Authors: Abaraya Seman , Biressa Tolu
Published: January 2021

Compact objects are of great interest in astrophysical research. There are active research interests in understanding better various aspects of formation and evolution of these objects. In this paper we addressed some problems related to the compact objects mass limit. We employed Einstein field equations (EFEs) to derive the equation of state (EoS). With the assumption of high densities and low temperature of compact sources, the derived equation of state is reduced to polytropic kind. Studying the polytropic equations we obtained similar physical implications, in agreement to previous works. Using the latest version of Mathematica-11 in our numerical analysis, we also obtained similar results except slight differences in accuracy.
Mass-loss varying luminosity and its implication to the solar evolution
Authors: Tilahun Shukure Negessa , Tessema Solomon Belay , Mengistu Endalkachew
Published: January 2021

Several models of the solar luminosity, , in the evolutionary timescale, have been computed as a function of time. However, the solar mass-loss, , is one of the drivers of variation in this timescale. The purpose of this study is to model mass-loss varying solar luminosity, , and to predict the luminosity variation before it leaves the main sequence. We numerically computed the up to 4.9 Gyrs from now. We used the solution to compute the modeled . We then validated our model with the current solar standard model (SSM). The shows consistency up to 8 Gyrs. At about 8.85 Gyrs, the Sun loses 28% of its mass and its luminosity increased to 2.2. The model suggests that the total main sequence lifetime is nearly 9 Gyrs. The model explains well the stage at which the Sun exhausts its central supply of hydrogen and when it will be ready to leave the main sequence. It may also explain the fate of the Sun by making some improvements in comparison to previous models.
The Association Between Chronic Disease and Psychological Distress: An Australian Twin Study
Authors: Tyler Jessica , Lam Janine , Scurrah Katrina , Dite Gillian
Published: January 2021

There is a commonly observed association between chronic disease and psychological distress, but many potential factors could confound this association. This study investigated the association using a powerful twin study design that can control for unmeasured confounders that are shared between twins, including genetic and environmental factors. We used twin-paired cross-sectional data from the Adult Health and Lifestyle Questionnaire collected by Twins Research Australia from 2014 to 2017. Linear regression models fitted using maximum likelihood estimations (MLE) were used to test the association between self-reported chronic disease status and psychological distress, measured by the Kessler Psychological Distress Scale (K6). When comparing between twin pairs, having any chronic disease was associated with a 1.29 increase in K6 (95% CI: 0.91, 1.66; p < .001). When comparing twins within a pair, having any chronic disease was associated with a 0.36 increase in K6 (95% CI: 0.002, 0.71; p = .049). This within-pair estimate is of most interest as comparing twins within a pair naturally controls for shared factors such as genes, age and shared lived experiences. Whereas the between-pair estimate does not. The weaker effect found within pairs tells us that genetic and environmental factors shared between twins confounds the relationship between chronic disease and psychological distress. This suggests that associations found in unrelated samples may show exaggerated estimates.
Non‐Linear Response of Ammonia Volatilization to Periphyton in Paddy Soils
Authors: Huang Jing , Liu Xuemei , Liu Yuqing , Yan Xing , Yan Xiaoyuan , Wu Yonghong , Xia Yongqiu
Published: January 2021

Ammonia (NH3) volatilization from paddy soils is one of the main contributors to agricultural NH3 emissions, however, little attention has been paid to the role of the ubiquitous periphyton in paddy soils on NH3 volatilization. Considering that the composition of periphyton is dominated by autotrophs that directly affect the redox and pH conditions, it is hypothesized that the presence of periphyton may be an important factor affecting NH3 emissions. In this study, NH3 volatilization was determined under six periphyton biomass treatments and under treatments with six different N application rates to evaluate the contribution of periphyton to NH3 volatilization in the laboratory representing the paddy soils system. Results showed that periphyton had trade‐off effects on NH3 volatilization through pH and the NH4+ concentration. Periphyton had net inhibition effects on NH3 volatilization when the periphyton biomass was higher than 110 g·m−2. In contrast, periphyton had net promotion effects on NH3 volatilization when the periphyton biomass was less than 110 g·m−2. The contribution of periphyton to NH3 volatilization increased exponentially with increasing N application rates (i.e., with the increasing nitrogen concentration of the overlying water). In the low‐nitrogen treatments (≤20 kg N·ha−1), periphyton had no significant effect on NH3 volatilization. In contrast, periphyton contributed as much as 47.4% of NH3 volatilization at high nitrogen concentrations (100 kg N·ha−1). This study provides valuable insight into the role of periphyton on NH3 volatilization, offers quantified relationship between periphyton and NH3 volatilization, and improves the accuracy of NH3 volatilization estimation in regional paddy soils.
PDX1LOW MAFALOW β-cells contribute to islet function and insulin release
Authors: Nasteska Daniela , Fine Nicholas H. F. , Ashford Fiona B. , Cuozzo Federica , Viloria Katrina , Smith Gabrielle , Dahir Aisha , Dawson Peter W. J. , Lai Yu-Chiang , Bastidas-Ponce Aimée , Bakhti Mostafa , Rutter Guy A. , Fiancette Remi , Nano Rita , Piemonti Lorenzo , Lickert Heiko , Zhou Qiao , Akerman Ildem , Hodson David J.
Published: January 2021

Transcriptionally mature and immature β-cells co-exist within the adult islet. How such diversity contributes to insulin release remains poorly understood. Here we show that subtle differences in β-cell maturity, defined using PDX1 and MAFA expression, contribute to islet operation. Functional mapping of rodent and human islets containing proportionally more PDX1HIGH and MAFAHIGH β-cells reveals defects in metabolism, ionic fluxes and insulin secretion. At the transcriptomic level, the presence of increased numbers of PDX1HIGH and MAFAHIGH β-cells leads to dysregulation of gene pathways involved in metabolic processes. Using a chemogenetic disruption strategy, differences in PDX1 and MAFA expression are shown to depend on islet Ca2+ signaling patterns. During metabolic stress, islet function can be restored by redressing the balance between PDX1 and MAFA levels across the β-cell population. Thus, preserving heterogeneity in PDX1 and MAFA expression, and more widely in β-cell maturity, might be important for the maintenance of islet function.
Universally bistable shells with nonzero Gaussian curvature for two-way transition waves
Authors: Vasios Nikolaos , Deng Bolei , Gorissen Benjamin , Bertoldi Katia
Published: January 2021

Multi-welled energy landscapes arising in shells with nonzero Gaussian curvature typically fade away as their thickness becomes larger because of the increased bending energy required for inversion. Motivated by this limitation, we propose a strategy to realize doubly curved shells that are bistable for any thickness. We then study the nonlinear dynamic response of one-dimensional (1D) arrays of our universally bistable shells when coupled by compressible fluid cavities. We find that the system supports the propagation of bidirectional transition waves whose characteristics can be tuned by varying both geometric parameters as well as the amount of energy supplied to initiate the waves. However, since our bistable shells have equal energy minima, the distance traveled by such waves is limited by dissipation. To overcome this limitation, we identify a strategy to realize thick bistable shells with tunable energy landscape and show that their strategic placement within the 1D array can extend the propagation distance of the supported bidirectional transition waves.
De novo DNA methyltransferase activity in colorectal cancer is directed towards H3K36me3 marked CpG islands
Authors: Masalmeh Roza H. Ali , Taglini Francesca , Rubio-Ramon Cristina , Musialik Kamila I. , Higham Jonathan , Davidson-Smith Hazel , Kafetzopoulos Ioannis , Pawlicka Kamila P. , Finan Hannah M. , Clark Richard , Wills Jimi , Finch Andrew J. , Murphy Lee , Sproul Duncan
Published: January 2021

The aberrant gain of DNA methylation at CpG islands is frequently observed in colorectal tumours and may silence the expression of tumour suppressors such asMLH1. Current models propose that these CpG islands are targeted by de novo DNA methyltransferases in a sequence-specific manner, but this has not been tested. Using ectopically integrated CpG islands, here we find that aberrantly methylated CpG islands are subject to low levels of de novo DNA methylation activity in colorectal cancer cells. By delineating DNA methyltransferase targets, we find that instead de novo DNA methylation activity is targeted primarily to CpG islands marked by the histone modification H3K36me3, a mark associated with transcriptional elongation. These H3K36me3 marked CpG islands are heavily methylated in colorectal tumours and the normal colon suggesting that de novo DNA methyltransferase activity at CpG islands in colorectal cancer is focused on similar targets to normal tissues and not greatly remodelled by tumourigenesis.
Infrared nanospectroscopy reveals the molecular interaction fingerprint of an aggregation inhibitor with single Aβ42 oligomers
Authors: Ruggeri Francesco Simone , Habchi Johnny , Chia Sean , Horne Robert I. , Vendruscolo Michele , Knowles Tuomas P. J.
Published: January 2021

Significant efforts have been devoted in the last twenty years to developing compounds that can interfere with the aggregation pathways of proteins related to misfolding disorders, including Alzheimer’s and Parkinson’s diseases. However, no disease-modifying drug has become available for clinical use to date for these conditions. One of the main reasons for this failure is the incomplete knowledge of the molecular mechanisms underlying the process by which small molecules interact with protein aggregates and interfere with their aggregation pathways. Here, we leverage the single molecule morphological and chemical sensitivity of infrared nanospectroscopy to provide the first direct measurement of the structure and interaction between single Aβ42 oligomeric and fibrillar species and an aggregation inhibitor, bexarotene, which is able to prevent Aβ42 aggregation in vitro and reverses its neurotoxicity in cell and animal models of Alzheimer’s disease. Our results demonstrate that the carboxyl group of this compound interacts with Aβ42 aggregates through a single hydrogen bond. These results establish infrared nanospectroscopy as a powerful tool in structure-based drug discovery for protein misfolding diseases.