bluuebunny/crossref_metadata_2025 huggingface dataset:
PP48 Risk Of Bias Of Systematic Reviews Connected To Journal Impact Factor?
Authors: Carrera Vanesa Huertas , Worthy Gill , Kleijnen Joseph
Published: December 2019

Introduction

Systematic reviews (SRs) are today's cornerstone of evidence-based medicine. However, their risk of bias (ROB) may critically impact their findings. Hence, an impartial assessment of their ROB is paramount to their interpretation. The objective of this study is to evaluate the potential association between the results of the ROB assessment for a series of SRs and their corresponding journal's impact factor as determined by the citation reports.

Methods

A sample of over 500 SRs and their corresponding ROB will be employed in this study. The source for these data will be the database KSR Evidence. The corresponding impact factor (IF) for the publishing journal as reported by the Science Citation Index will also be retrieved. The total of ROBIS signaling questions answered as ‘yes’ or ‘probably yes’ will be used to approximate the awarded quality (Quality) for each systematic review. An analysis of the potential correlation between Quality and the IF will be performed with a simple linear regression.

Results

Results will be presented in tables and figures. Preliminary results confirm that a statistically significant association between the suggested variables exists, though this is of low magnitude.

Conclusions

Findings confirm that the ROB of an SR and the IF of the publishing journal are correlated.
PP65 Methods Applied For Systematic Reviews Of Economic Evaluations In Health Technology Assessment
Authors: Luhnen Miriam , Prediger Barbara , Neugebauer Edmund A.M. , Mathes Tim
Published: December 2019

Introduction

When making decisions in health care, it is essential to consider economic evidence about an intervention. The objective of this study was to analyze the methods applied for systematic reviews of economic evaluations in Health Technology Assessment (HTA) and to identify common challenges.

Methods

We manually searched the webpages of HTA organizations and included HTA-reports published since 2015. Prerequisites for inclusion were the conduct of a systematic review of economic evaluations in at least one electronic database and the use of the English, German, French, or Spanish language. Methodological features were extracted in standardized tables. We prepared descriptive statistical (e.g., median, range) measures to describe the applied methods. Data were synthesized in a structured narrative way.

Results

Eighty-three reports were included in the analysis. We identified inexplicable heterogeneity, particularly concerning literature search strategy, data extraction, assessment of quality, and applicability. Furthermore, process steps were often missing or reported in a nontransparent way. The use of a standardized data extraction form was indicated in one-third of reports (32 percent). Fifty-four percent of authors systematically appraised included studies. In 10 percent of reports, the applicability of included studies was assessed. Involvement of two reviewers was rarely reported for the study selection (43 percent), data extraction (28 percent), and quality assessment (39 percent).

Conclusions

The methods applied for systematic reviews of economic evaluations in HTA and their reporting quality are very heterogeneous. Efforts toward a detailed, standardized guidance for the preparation of systematic reviews of economic evaluations definitely seem necessary. A general harmonization and improvement of the applied methodology would increase their value for decision makers.
PP78 Analysis Of Resource Utilization In Psoriasis Care In The Brazilian Health System
Authors: Costa Andrade Larissa de Araujo , Moreira Ricardo , Vitale Vinicius
Published: December 2019

Introduction

Psoriasis is associated with metabolic disorders and has a significant negative impact on patients’ quality of life. There is little information about treatment patterns and the resources used to treat psoriasis and its associated comorbidities. This study aimed to evaluate the frequency of metabolic syndrome (MetS) and estimate the costs associated with psoriasis care in the Brazilian health system.

Methods

A cross-sectional observational study was conducted of 293 Brazilian patients with psoriasis who attended selected dermatology outpatient centers in Brazil during a one-year period. Patients underwent detailed skin and rheumatologic assessments and a series of laboratory tests. The annual costs were estimated by multiplying the amount of each resource consumed by its unit cost.

Results

The prevalence rate of MetS was high in this cohort (50%). Other metabolic disorders were more common in this group than in the general population, including hypertension (62%), diabetes (31%), dyslipidemia (75%), and obesity (53%). The disease duration was, on average, 17.2 years. There were 2,713 consultations reported by 288 patients (average of nine per patient per year). The most common specialists consulted were: dermatologists (93%); general practitioners (41%); cardiologists (27%); rheumatologists (18%); and endocrinologists (13%). There were 110 non-physician visits (average of 11 per patient per year), of which the most frequently consulted specialists were nutritionists (26%), psychologists (24%), and nurses (22%). A total of 279 patients (95%) had at least one medical test (average of 18 per patient per year). Among the treatments required for other conditions, 65% (n = 149) of prescribed medicines were for the cardiovascular system and 24% (n = 5/21) of hospitalizations were due to diseases of the circulatory system; myocardial revascularization was the costliest procedure (USD 2,298).

Conclusions

MetS is frequently associated with psoriasis and directly affects health resource utilization in the Brazilian health system by increasing consultation costs. Further research is needed to evaluate the impact of a multidisciplinary treatment approach for psoriasis patients with MetS.
PP80 A Systematic Review Of The Gugging Swallowing Screen For Assessing Dysphagia
Authors: Lee Seon Heui
Published: December 2019

Introduction

Dysphagia is a clinical burden that can lead to serious complications like aspiration and pneumonia. Complications often result in longer hospital stays or an increased mortality rates. The Gugging Swallowing Screen (GUSS) assesses swallowing ability in patients by allowing separate evaluations for non-fluid and fluid textures, and is a potentially useful tool for determining the risk of aspiration and dysphagia. The purpose of this study is to analyze the validity and effectiveness of GUSS for dysphagia screening.

Methods

We conducted a systematic review by searching the following electronic databases: Medline, EMBASE, The Cochrane Library, KoreaMed, the Research Information Sharing Service, and the Korean Studies Information Service System. We included studies related to dysphagia screening with GUSS that were published in English or Korean up to November 2018.

Results

Of 297 unique studies identified, 219 were reviewed by two independent reviewers. Finally, eight articles were identified as being relevant for this study. With regard to validity, GUSS had a sensitivity ranging from 90 to 100 percent and a specificity of between 50 and 88 percent. In addition, GUSS results significantly correlated with the results of the videofluoroscopic swallow study and the fiberoptic endoscopic evaluation of swallowing. In terms of effectiveness, early systematic dysphagia screening with GUSS by nurses reduced the duration of screening and rate of pneumonia, compared with the control group (p = 0.004). The incidence of X-ray verified pneumonia in the GUSS group was also significantly lower than in the clinical screening group (p < 0.01), although there was no difference in the occurrence of pneumonia, compared with the 10 mL water swallowing test.

Conclusions

Results showed that GUSS is a reliable and sensitive tool for screening patients for dysphagia. This early and systematic assessment can reduce the occurrence of aspiration and pneumonia, although further research is needed to establish the effectiveness of GUSS.
PP135 Setting The Scope For Assessing e-Health Technologies In Hungary
Authors: Takács Bence , Merész Gergő
Published: December 2019

Introduction

E-health and m-health are emerging health technology fields that could possibly give a new scope to health technology assessment (HTA). The Division for Health Technology Assessment (DfHTA) is currently assessing medicines and non-drug technologies (medical devices intended for patient use or for use in hospitals). The experience assessing medical devices for use in hospitals yielded difficulties which could also arise from the critical appraisal of e-health or m-health technologies. The objective of this study was to explore the foundations for HTA guidance on e-health or m-health technologies.

Methods

A targeted literature review was conducted to map the current status of technology assessment practices for e-health and m-health technologies and to assess its concordance with current reimbursement processes in countries belonging to the Organisation for Economic Co-operation and Development. Experiences from past evaluations of other medical devices that could not be evaluated under the current guidance guided the literature search. The findings of this research were used to create a recommendation to amend the current Hungarian Guideline for Health Economic Analyses.

Results

The resulting articles of the targeted literature review provided an insight into current practices on of assessing e-health and m-health products, particularly with respect to the domains of safety, quality, and impact. Recommendations suggested including a list of requirements for companies to submit for critical evaluations of e-health and m-health technologies, in support of a self-assessment approach.

Conclusions

As for other HTA bodies, there is an urgent need for the DfHTA to increase its capacity to assess digital health technologies for entry into the healthcare system, with a focus on the relevant clinical domains. The reimbursement process for these technologies remains a challenge for public funding bodies.
PP136 How To Apply Health Technology Assessment To Large Scale e-Health Processes
Authors: Severinsen Gro-Hilde , Silsand Line , Ekeland Anne
Published: December 2019

Introduction

There are enormous expectations for e-health solutions to support high quality healthcare services, with accessibility, and effectiveness as key goals. E-health encompasses a wide range of information and communication technologies applied to health care, and focuses on combining clinical activity, technical development, and political requirements. Hence, e-health solutions must be evaluated in relation to the desired goals, to justify the high costs of such solutions.

Methods

Health technology assessment (HTA) aims to produce rational decisions for purchasing new technologies and evaluating healthcare investments, like drugs and medical equipment, by measuring added value in relation to clinical effectiveness, safety, and cost effectiveness. It is desired to also apply HTA assessment on large scale e-health solutions, but traditional quantitative HTA methodology may not be applicable to complex e-health systems developed and implemented as ongoing processes over years. Systematic reviews and meta-analyses of these processes risk being outdated when published, therefore action research designed to work with complex, large scale programs may be a more suitable approach.

Results

In the project, we followed the development of a new process-oriented electronic patient record system (EPR) in northern Norway. Part of the process was structuring clinical data to be used in electronic forms within the system. This was the first time a health region structured the clinical data and designed the forms; receiving feedback alongside the process was very important. The goal was to use structured forms as a basis for reusing EPR data within and between systems, and to enable clinical decision support.

Discussion

After designing a prototype of a structured form, we wrote an assessment report focusing on designing a methodology for such development, which stakeholders to include, and how to divide the work between the health region and the system vendor. The answers to such questions will have both practical and economic consequences for designing the next phase of the process.
PP173 Is Early Modelling Too Late? Preventing Pitfalls And Optimizing Value
Authors: Berardi Andrea , Macaulay Richard , Johal Sukhvinder
Published: December 2019

Introduction

Drug development is a risky business. Manufacturers are faced with the dilemma of whether or not to invest at any stage in the development process. Even once marketing authorization has been attained, payers are becoming increasingly demanding of evidence to justify price premiums in the face of increasing budgetary pressures. Cost-effectiveness is a critical decision-making criterion for many payers, and restrictions to sub-populations is common. Early economic modelling at very early phases of the development pathway can inform optimal investment decision-making, including go/no-go decisions and clinical trial design, particularly in population selection. To test the hypothesis of changing payer requirements, we carried out a study on the trends in reimbursement submissions where payers approved but ultimately restricted the population compared to the marketing license or the company's target population.

Methods

A systematic literature review of all single technology appraisals (STAs) by the National Institute for Health and Clinical Excellence (NICE) was carried (01/01/2006- to 16/11/2018). We used a linear regression model to examine the relationship between frequency of optimizations and time.

Results

In total, 357 STAs outcomes were identified, 55 percent were recommended and 26 percent were optimized. The proportion of optimized recommendations increased over time vs all other outcomes (p = 0.01), with more technologies being optimized over time (p < 0.01).

Conclusions

The results indicate an increasing trend by NICE towards maximization of value through approval of drugs in select groups of patients. From a manufacturer's perspective, prediction of such outcomes at an early stage is fundamental for investment purposes and to maximize financial returns. An early stage model provides a framework to examine these issues as well as identifying data gaps, where real world evidence can be planned to support the value argument for products, and to inform clinical trial design through value of information analysis.
PP178 Health Technology Assessment Of Laboratory Medicine
Authors: Di Mauro Roxana , Faggiano Francesco , Andellini Martina , Derrico Pietro , Ritrovato Matteo
Published: December 2019

Introduction

Recent studies have investigated the re-organization and automation of laboratory medicine as a challenge for the hospital in terms of reduction of costs, turnaround time, workload, optimization of human and technological resources and improvement of safety. The purpose of this study was to conduct a health technology assessment (HTA) evaluation process about the possibility to re-organize and automate laboratory medicine at Bambino Gesù Children's Hospital.

Methods

The decision-oriented HTA (Do-HTA) method, involving the integration of the European Network for HTA (EUnetHTA) CoreModel and the Analytic Hierarchy Process, was applied to assess the best technology solution. Twenty-one professionals were involved to define tender specifications related to the adaptation works of the new dedicated rooms, and the automatic technologies and organizational solutions for the new laboratory department. Finally, two manufacturer companies were consulted.

Results

Using Do-HTA, the study was focused on laboratory technologies while the infrastructure evaluation was conducted by the Engineering and Logistic Units of the hospital. Results showed that the total performance score of the first proposal was slightly higher (2.5 percent) than the second one, proving the comparable high qualitative level of both manufactures technologies. After an accurate analysis, evaluating all aspects (safety, clinical efficacy, cost, organization & technical criteria) and integrating the infrastructure evaluation, the decision has fallen upon the first company offer.

Conclusions

This HTA project provided an in-depth examination of two proposed technological and organizational solutions. Thanks to the Do-HTA method, which produced and developed data and all needed information, it was possible to guide and assist the decision makers on the choice between the two technical solutions.
VP22 Applying The IDEAL Framework To NICE Interventional Procedure Guidance
Authors: Anjum Sharika , Powell John , Harris Kevin
Published: December 2019

Introduction

The IDEAL (Idea, Development, Exploration, Assessment, Learning) Framework measures the maturity of evidence base behind surgical innovation. The NICE Interventional Procedures (IP) programme issues guidance for the United Kingdom National Health Service (NHS) on use of surgical innovation. One of four recommendations can be made: (a) standard arrangements, (b) special arrangements, (c) research only, and (d) do not use. This study aimed to investigate whether the recommendation of NICE IP guidance corresponded with the stage of innovation as determined by IDEAL, thus IDEAL's role in informing future guidance production.

Methods

A retrospective sample of 103 pieces of guidance issued between 2015 and 2018 was analysed. One researcher examined the evidence base and determined the corresponding stage of the IDEAL framework, numbered 1, 2, 2a, 3 and 4. The primary outcome measure was the association between stage of evidence on IDEAL framework and the recommendation of published NICE IP guidance.

Results

There were twenty-one (20 percent), thirty-three (32 percent), three (3 percent), forty (39 percent) and six (6 percent) procedures at IDEAL stages 1, 2, 2a, 3 and 4, respectively. Of those at stage 1 (idea), 48 percent were given research only arrangements, 43 percent special arrangements, and 10 percent standard. Many of the procedures at stages 2 (development) and 2a (exploration) were given standard arrangements (39 percent and 67 percent respectively). Forty-three percent of stage 3 (assessment) and 67 percent of stage 4 (learning) guidance were identified standard. At stage 4 none were given a ‘research only’ recommendation.

Conclusions

Procedures given ‘standard’ arrangements guidance are more likely have a mature and robust evidence base as determined by IDEAL. Those with limited evidence are more likely to be given a more cautious ‘research only’ guidance. Routine use of this framework could help inform future guidance production however cannot replace the decision-making function of the NICE committee which also involves patient experiences, population characteristics, risk of serious safety events, and equity issues.
VP37 Patient Involvement In EUnetHTA Assessments (Non-Pharma Technologies)
Authors: Ettinger Sabine , Erdos Judit , De Villiers Cecilia
Published: December 2019

Introduction

Patients can provide valuable experience on living with diseases, health-related quality of life, various therapies and relevant outcomes. Their input and perspectives can be helpful in complementing health technology assessment (HTA) processes. The European Network for HTA (EUnetHTA), funded by the European Commission, aims to further advance and standardise patient involvement processes in order to add to the quality and applicability of HTAs and to allow capability building.

Methods

Different methods for patient involvement in HTAs on non-pharmaceutical technologies were tested: Patient input templates (open questions sent to relevant patient organizations, or published on EUnetHTA website); scoping meeting with patients/patient representatives; one-on-one conversation and group conversation. Applied methods depended on the scope of the HTA and other factors like timelines of HTAs and burden of disease for patients.

Results

Patients were included in eight of sixteen HTAs on non-pharmaceutical technologies. Applied methods were: group conversation (n = 2), scoping meeting (n = 1), patient input templates (n = 4), one-on-one conversation (n = 2,) and other approach (i.e. written feedback on scope n= 2). In some HTAs more than one method was used. Main reasons for not including patients were inability to identify suitable patients or tight timelines. Patients' feedback on health-related quality of life and outcome measures proved most useful in the scoping phase.

Conclusions

The different approaches were useful for complementing HTA processes. Those need to be further tested and evaluated in order to formulate deeper understanding about the impact of patient involvement on HTA. Additionally, feedback from patients that were actively involved in the HTAs should be collected to further improve the involvement methods that should serve as basis for future recommendations post 2020.
VP54 Digital Tools For More Efficient Conduct Of RCTs: Trials Unit Survey
Authors: Nuttall Jacqui , Lane Athene , Blatch-Jones Amanda , Griffiths Gareth , Wyatt Jeremy
Published: December 2019

Introduction

Recruitment of participants to, and their retention in, Randomized Controlled Trials (RCTs) is a key determinant of research efficiency, but is challenging. Digital tools and media are increasingly used to reduce costs, waste and delays in the conduct and delivery of research. The aim of this UK Clinical Trials Unit (CTU) survey was to identify which digital recruitment and retention tools are being used to support RCTs, their benefits and success characteristics.

Methods

A survey was sent to all UK Clinical Research Collaboration (UKCRC)-registered CTUs with a webinar to help increase completion. A logic model and definitions of a “digital tool” were developed by iterative refinement by project team members, the Advisory Board (NIHR Research Design service, NHS Trust, NIHR Clinical Research Networks and patient input) and CTUs.

Results

A total of 24/52 (46%) CTUs responded, 6 (25%) of which stated no prior use. Database screening tools (e.g. CPRD, EMIS) were the tool most widely used (45%) for recruitment and were considered very effective (67%). The most mentioned success criteria were saving GP time and reaching more patients. Social media was second (27%), but estimated effectiveness varied considerably, with only 17% stating very effective. Fewer retention tools were used, with SMS / email reminders reported most (10/15 67%), but certainty about effectiveness varied. A detailed definition on what constitutes a digital tool with examples and a logic model showing relationships between the resources, activities, outputs and outcomes for digital tools was developed.

Conclusions

Database screening tools are the most commonly used digital tool for recruitment, with clear success criteria and certainty about effectiveness. Our detailed definition of what constitutes a digital tool, with examples, will inform the NIHR research community about choices and help them identify potential tools to support recruitment and retention.
VP83 Health Economics Distance Learning For Healthcare Workers In Brazil
Authors: Bagattini Ângela , Marçal dos Santos Adélia , Juk Juliana , Soares Renata , Piola Sergio , Toscano Cristiana
Published: December 2019

Introduction

Despite increased healthcare systems costs, limited opportunities for health economics training are available to healthcare professionals. From 2016-2018, with a grant from the Brazilian Ministry of Health, the Federal University of Goias with 7 other universities, implemented the distance learning Postgraduate Certificate in Health Economics for Health Care Professionals (PCHE) aimed at enhancing technical capacity of professionals working in the Brazilian Public Healthcare System (SUS).

Methods

This is a descriptive and qualitative assessment of the PCHE implemented in Brazil 88 healthcare professionals working in SUS and involved in decision making in all levels of managament were enrolled in a health economics training, through long-distance learning strategy. We present course metrics, describe its workload, content, modalities and structure of training.

Results

PCHE was structured with 3-day workshops introducing each of the modules, during which students were also evaluated regarding the previous module content. With a total workload of 360 hours, structured in four modules: Public Health and Epidemiology; Introduction to health economics and healthcare funding; Management of healthcare resources; and Healthcare economic evaluation. The module coordinator was resposible for supervision of course materials development, workshop, distance based tutoring activities, and evaluation. Course material included theorethical content and practical tools for economic evaluation and health technology assessment in the workplace, applying problem-based learning strategies. Certificates were granted to students with 75 percent presence and approved in all modules, and final papers approved by an examination board. Each module was completed in 8 weeks (90 hours/module). Within groups of 20 students, tutors performed communication witn chats twice weekly and discussion forums by topic.. A total of 88 students were enrolled. Drop-out rate was 35.2 percent (n = 31). Additional 10 students did not pass the exams. In total, 47 students completed the training.

Conclusions

Health economics training through distance learning is a more efficient use of resources with good results.
VP95 Getting the Best Of 3 Ways-Merging EUnetHTA GRADE And Cochrane Guides
Authors: Ballini Luciana , Formoso Giulio , Bassi Maria Chiara , Bonvicini Laura , Bottazzi Paolo , Rossi Paolo Giorgi , Venturelli Francesco , Vicentini Massimo
Published: December 2019

Introduction

European cooperation in Health Technology Assessment (HTA) requires joint assessments to be of high quality, providing findings transferable into national HTA report. To this aim, we piloted the combining of methodological guidance of EUnetHTA for Relative Effectiveness Assessment (REA), GRADE for selection/rating of outcomes and assessing quality of evidence, and Cochrane for Systematic Reviews, while carrying out a collaborative REA on Femtosecond Laser Assisted versus Standard Cataract Surgery.

Methods

While developing the collaborative REA, we used the three organizations’ handbooks, templates and tools for Scope, Project Plan (PP), Summary of Findings, Effectiveness (EFF) and Safety (SAF) domains. We structured the PP according to the EUnetHTA template and added detailed methods on EFF and SAF systematic reviews, as per Cochrane Handbook. For the Scope we convened a multidisciplinary panel for selection and rating of importance of outcomes and clinically significant difference, using the GRADEpro platform. We developed the complete report adopting the EUnetHTA REA Core Model. We used Cochrane's tool Revman to assess risk of bias of included studies for each outcome, and to carry out metanalyses. We applied the GRADE approach to assess quality of evidence for each outcome and to express level of certainty in the estimates. We used the Cochrane handbook's guidance for structuring a scientific abstract and a Plain Language Summary to integrate the Summary of Findings.

Results

The PP resulted in a detailed scientific and operational protocol, receiving extensive and constructive internal and external peer review. Reporting of EFF and SAF domains followed EUnetHTA Assessment Elements while keeping the order of stakeholders' rating of outcomes’ importance. Graphic representation of risk of bias for each outcome contributed to immediacy of the data quality assessment and transparency of the judgement on certainty. The scientific abstract and the Plain Language Summary, facilitated the external dissemination of results.

Conclusions

Merging of the three most important methodological contributions in the field proved successful without altering the distinctive trait of the REA.
VP101 Intrauterine Surgical Interventions: A Rapid Review
Authors: de Aguiar Aurelina Aguiar , Farinasso Cecilia , Rego Daniela , Simões Luciana , Leão Camara , Silva Roberta Borges , Gomes Dalila , Sachetti Camile Giaretta
Published: December 2019

Introduction

Adverse conditions during pregnancy, such as myelomeningocele (MMC), fetal-fetal transfusion syndrome (STFF) and congenital heart disease (CHD) not only significantly increase the risk of fetal death, but also increase the occurrence of severe postnatal sequelae.

Methods

We conducted a rapid review of the efficacy and safety of intrauterine interventions in MMC, STFF and DCC in comparison to traditional interventions. We searched Pubmed via Medline, Cochrane Library and Center for Reviews and Dissemination databases using the terms indexed and synonyms for each intervention.

Results

For STFF, the available scientific evidence indicates that laser ablation is effective and presents better outcomes when compared to other interventions, such as high overall survival rate, better perinatal outcomes and less chance of brain injury. Even though intrauterine interventions in CHD present high rates of live births, high neonatal mortality rates are also reported. Evidence on the efficacy and safety of intrauterine surgical interventions for myelomeningocele and CHD is inconclusive. Regarding myelomeningocele, no significant differences were observed for the outcomes of postnatal mortality, rate of ventriculostomy placement, reversal of posterior brain herniation, motor response and placental rupture.

Conclusions

There is no consensus regarding the efficacy and safety of intrauterine surgical interventions for myelomeningocele and CHD. Regarding STFF, laser ablation is accepted as an effective intervention. It is necessary to conduct prospective studies in order to evaluate the effect of these interventions, considering the specifications of each condition and the ethical aspects.
Monitoring of the eclipsing Wolf-Rayet ULX in the Circinus galaxy
Authors: Qiu Yanli , Soria Roberto
Published: December 2019

. We studied the eclipsing ultraluminous X-ray source CG X-1 in the Circinus galaxy, re-examining two decades of Chandra and XMM-Newton observations. The short binary period (7.21 hr) and high luminosity (LX ≈ 1040 erg s-1) suggest a Wolf-Rayet donor, close to filling its Roche lobe; this is the most luminous Wolf-Rayet X-ray binary known to-date, and a potential progenitor of a gravitational-wave merger. We phase-connect all observations, and show an intriguing dipping pattern in the X-ray lightcurve, variable from orbit to orbit. We interpret the dips as partial occultation of the X-ray emitting region by fast-moving clumps of Compton-thick gas. We suggest that the occulting clouds are fragments of the dense shell swept-up by a bow shock ahead of the compact object, as it orbits in the wind of the more massive donor.
Studying the presence of magnetic fields in a sample of high-mass X-ray binaries
Authors: Hubrig Swetlana , Kholtygin Alexander F. , Sidoli Lara , Schöller Markus , Järvinen Silva P.
Published: December 2019

Previous circular polarization observations obtained with the ESO FOcal Reducer low dispersion spectrograpgh at the VLT in 2007–2008 revealed the presence of a weak longitudinal magnetic field on the surface of the optical component of the X-ray binary Cyg X-1, which contains a black hole and an O9.7Iab supergiant on a 5.6 d orbit. In this contribution we report on recently acquired FORS 2 spectropolarimetric observations of Cyg X-1 along with measurements of a few additional high-mass X-ray binaries.
Local merger rates of double neutron stars
Authors: Chruslinska Martyna
Published: December 2019

The first detection of gravitational waves from a merging double neutron star (DNS) binary implies a much higher rate of DNS coalescences in the local Universe than typically estimated on theoretical grounds. The recent study by Chruslinska et al. (2018) shows that apart from being particularly sensitive to the common envelope treatment, DNS merger rates appear rather robust against variations of several factors probed in their study (e.g. conservativeness of the mass transfer, angular momentum loss, and natal kicks), unless extreme assumptions are made. Confrontation with the improving observational limits may allow to rule out some of the extreme models. To correctly compare model predictions with observational limits one has to account for the other factors that affect the rates. One of those factors relates to the assumed history of star formation and chemical evolution of the Universe and its impact on the final results needs to be better constrained.
Spectroscopic identication of INTEGRAL high-energy sources with VLT/ISAAC
Authors: Fortin F. , Chaty S. , Coleiro A. , Tomsick J. A. , Nitschelm C. H. R.
Published: December 2019

INTEGRAL has been observing the γ-ray sky for 15 years and has discovered many high-energy sources of various nature. Among them, active galactic nuclei (AGN), low or high-mass X-ray binaries (LMXB and HMXB) and cataclysmic variables (CV) are rather difficult to differentiate from one another at high energies and require further optical or near-infrared observations to constrain their exact nature. Using near-infrared photometric and spectroscopic data from ESO VLT/ISAAC, we aim to reveal the nature of 14 high-energy INTEGRAL sources and improve the census of X-ray binaries. By comparing their spectral features to stellar spectra atlases, we identified 5 new CVs, 2 low or intermediate mass X-ray binaries, 2 HMXBs and 5 AGNs.
Orbital resolved spectroscopy of GX 301–2: wind diagnostics
Authors: Islam Nazma
Published: December 2019

GX 301–2, a bright high-mass X-ray binary with an orbital period of 41.5 days, exhibits stable periodic orbital intensity modulations with a strong pre-periastron X-ray flare. Several models have been proposed to explain the accretion at different orbital phases. In Islam & Paul (2014), we presented results from an orbital resolved spectroscopic study of GX 301–2 using data from MAXI Gas Slit Camera. We have found a strong orbital dependence of the absorption column density and equivalent width of the iron emission line. A very large equivalent width of the iron line along with a small value of the column density in the orbital phase range 0.1–0.3 after the periastron passage indicates the presence of high density accretion stream. We aim to further investigate the characteristics of the accretion stream with an AstroSat observation of the system.
3D time-dependent hydrodynamical and radiative transfer modeling of Eta Carinae’s innermost fossil colliding wind structures
Authors: Madura Thomas , Gull T. R. , Clementel N. , Corcoran M. , Damineli A. , Hamaguchi K. , Hillier D. J. , Moffat A. F. J. , Richardson N. , Weigelt G.
Published: December 2019

Eta Carinae is the most massive active binary within 10,000 light-years. While famous for the largest non-terminal stellar explosion ever recorded, observations reveal a supermassive (∼120 M⊙) binary consisting of an LBV and either a WR or extreme O star in a very eccentric orbit (e=0.9) with a 5.54-year period. Dramatic changes across multiple wavelengths are routinely observed as the stars move about in their highly elliptical orbits, especially around periastron when the hot (∼40 kK) companion star delves deep into the denser and much cooler (∼15 kK) extended wind photosphere of the LBV primary. Many of these changes are due to a dynamic wind-wind collision region (WWCR) that forms between the stars, plus expanding radiation-illuminated fossil WWCRs formed one, two, and three 5.54-year orbital cycles ago. These fossil WWCRs have been spatially and spectrally resolved by the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) at multiple epochs, resulting in data cubes that spatially map Eta Carinae’s innermost WWCRs and follow temporal changes in several forbidden emission lines (e.g. [Fe iii] 4659 Å, [Fe ii] 4815 Å) across the 5.54-year cycle. We present initial results of 3D time-dependent hydrodynamical and radiative-transfer simulations of the Eta Carinae binary and its WWCRs with the goal of producing synthetic data cubes of forbidden emission lines for comparison to the available HST/STIS observations. Comparison of the theoretical models to the observations reveals important details about the binary’s orbital motion, photoionization properties, and recent (5–15year) mass loss history. Such an analysis also provides a baseline for following future changes in Eta Carinae, essential for understanding the late-stage evolution of a nearby supernova progenitor. Our modeling methods can also be adapted to a number of other colliding wind binary systems (e.g. WR 140) that are scheduled to be studied with future observatories (e.g. the James Webb Space Telescope).
Ultraluminous X-ray source populations in the Chandra Source Catalog 2.0
Authors: Kovlakas Konstantinos , Zezas Andreas , Andrews Jeff J. , Basu-Zych Antara , Fragos Tassos , Hornschemeier Ann , Lehmer Bret , Ptak Andrew
Published: December 2019

. The nature and evolution of ultraluminous X-ray sources (ULXs) is an open problem in astrophysics. They challenge our current understanding of stellar compact objects and accretion physics. The recent discovery of pulsar ULXs further demonstrates the importance of this intriguing and rare class of objects.

In order to overcome the difficulties of directly studying the optical associations of ULXs, we generally resort in statistical studies of the stellar properties of their host galaxies. We present the largest such study based on the combination of Chandra archival data with the most complete galaxy catalog of the Local Universe. Incorporating robust distances and stellar population parameters based on associated multi-wavelength information, and we explore the association of ULXs with galaxies in the (star formation rate, stellar mass, metallicity) space.

We confirm the known correlation with morphology, star formation rate and stellar mass, while we find an excess of ULXs in dwarf galaxies, indicating dependence on age and metallicity.
Multifractal signatures of gravitational waves detected by LIGO
Authors: de Freitas Daniel B. , Nepomuceno Mackson M. F. , De Medeiros J. R.
Published: December 2019

We analyze the data from the 6 gravitational waves signals detected by LIGO through the lens of multifractal formalism using the MFDMA method, as well as shuffled and surrogate procedures. We identified two regimes of multifractality in the strain measure of the time series by examining long memory and the presence of nonlinearities. The moment used to divide the series into two parts separates these two regimes and can be interpreted as the moment of collision between the black holes. An empirical relationship between the variation in left side diversity and the chirp mass of each event was also determined.
The X-ray binary populations of M81 and M82
Authors: Sell Paul H. , Zezas Andreas , Williams Stephen J. , Andrews Jeff J. , Gazeas Kosmas , Gallagher John S. , Ptak Andrew
Published: December 2019

We use deep Chandra and HST data to uniquely classify the X-ray binary (XRB) populations in M81 on the basis of their donor stars and local stellar populations (into early-type main sequence, yellow giant, supergiant, low-mass, and globular cluster). First, we find that more massive, redder, and denser globular clusters are more likely to be associated with XRBs. Second, we find that the high-mass XRBs (HMXBs) overall have a steeper X-ray luminosity function (XLF) than the canonical star-forming galaxy XLF, though there is some evidence of variations in the slopes of the sub-populations. On the other hand, the XLF of the prototypical starburst M82 is described by the canonical powerlaw (αcum ∼ 0.6) down to LX ∼ 1036 erg s−1. We attribute variations in XLF slopes to different mass transfer modes (Roche-lobe overflow versus wind-fed systems).
Be stars in the X-ray binary context
Authors: Rivinius Thomas
Published: December 2019

Rapidly rotating B-type stars with gaseous mass-loss disks in Keplerian rotation are common central objects in X-Ray binaries. These disks are physically well understood in the framework of the viscous decretion disk, and their typical parameters have been established for a large number of single Be stars in the recent years. According to the current observational evidence, the Be stars and disks found in BeXRBs are well within the boundaries known from single Be stars, i.e., they are normal Be stars. New results have also been obtained on the orbital disk truncation and other tidal effects of the companion objects on the disk.
Clumpy wind accretion in Supergiant X-ray Binaries
Authors: Mellah Ileyk El , Sander Andreas A. C. , Sundqvist Jon O. , Keppens Rony
Published: December 2019

Supergiant X-ray Binaries host a compact object, generally a neutron star, orbiting an evolved O/B star. Mass transfer proceeds through the intense radiatively-driven wind of the stellar donor, a fraction of which is captured by the gravitational field of the neutron star. The subsequent accretion process onto the neutron star is responsible for the abundant X-ray emission from those systems. They also display variations in time of the X-ray flux by a factor of a few 10, along with changes in the hardness ratios believed to be due to varying absorption along the line-of-sight. We used the most recent results on the inhomogeneities (aka clumps) in the non-stationary wind of massive hot stars to evaluate their impact on the time-variable accretion process. We ran three-dimensional simulations of the wind in the vicinity of the accretor to witness the formation of the bow shock and follow the inhomogeneous flow over several spatial orders of magnitude, down to the neutron star magnetosphere. In particular, we show that the impact of the clumps on the time-variability of the intrinsic mass accretion rate is severely damped by the crossing of the shock, compared to the purely ballistic Bondi-Hoyle-Lyttleton estimation. We also account for the variable absorption due to clumps passing by the line-of-sight and estimate the final effective variability of the mass accretion rate for different orbital separations. These results are confronted to recent analysis of Vela X-1 observations with Chandra by Grinberg et al. (2017). It shows that clumps account well for time-variability at low luminosity but can not generate, per se, the high luminosity activity observed.
ONe WD+He star systems as the progenitors of IMBPs
Authors: Wang Bo , Liu Dongdong
Published: December 2019

Previous theoretical studies can only explain part of the observed intermediate-mass binary pulsars (IMBPs) with short orbital periods. Note that an ONe white dwarf (WD) accreting mass from a He star may experience the accretion-induced collapse process and eventually form IMBPs, known as the ONe WD+He star scenario. By investigating the evolution of a large number of ONe WD+He star binaries, we found that the ONe WD+He star scenario can form IMBPs including pulsars with 5 – 340 ms spin periods, and the orbital periods range from 0.04 to 900 d. Compared with the observed IMBPs, this scenario can cover almost all of the IMBPs with short orbital periods. Thus, we suggest that the ONe WD+He star channel is responsible for the formation of IMBPs with short orbital periods.
X-ray binary Beta Lyrae and its donor component structure
Authors: Skulskyy M. Yu. , Vavrukh M. V. , Smerechynskyi S. V.
Published: December 2019

We show that the structure of magnetized accretion gas flows between the components of the Beta Lyrae system can cause a scattering gas shell that masks completely these components in soft X-ray region. Also we have calculated the inner structure of the donor that is filling a Roche lobe and is preceding a forming of the degenerate dwarf. We show that mass of the degenerate core of the donor is in region 0.3−0.5M⊙.
Massive star evolution revealed in the Mass-Luminosity plane
Authors: Higgins Erin R. , Vink Jorick S.
Published: December 2019

Massive star evolution is dominated by key physical processes such as mass loss, convection and rotation, yet these effects are poorly constrained, even on the main sequence. We utilise a detached, eclipsing binary HD166734 as a testbed for single star evolution to calibrate new MESA stellar evolution grids. We introduce a novel method of comparing theoretical models with observations in the ‘Mass-Luminosity Plane’, as an equivalent to the HRD (see Higgins & Vink 2018). We reproduce stellar parameters and abundances of HD166734 with enhanced overshooting (αov=0.5), mass loss and rotational mixing. When comparing the constraints of our testbed to the systematic grid of models we find that a higher value of αov=0.5 (rather than αov=0.1) results in a solution which is more likely to evolve to a neutron star than a black hole, due to a lower value of the compactness parameter.
Studying the H-alpha line of the B[ e ] supergiant binary GG Carinae using high-cadence optical spectroscopy
Authors: Porter Augustus , Blundell Katherine , Lee Steven
Published: December 2019

We present a case study of GG Carinae (GG Car), a Galactic B[ e ] supergiant binary having significant eccentricity (0.28), based on Global Jet Watch spectroscopy data which has been collecting high-time-sampled optical spectra since early 2015. GG Car has so far not been observed in the X-ray band, however it is of similar phenomenology to known X-ray binaries and may therefore be an obscured X-ray source. We have discovered that the absorption component of the H-alpha line displays a ∼62-478-day period in both equivalent width and wavelength centroid indicating cycles in the dynamics of the circumstellar environment, such as precession of the circumbinary or circumprimary disk. Circumbinary disk precession is an as-of-yet underexplored origin of super-orbital variations in the X-ray flux of X-ray binaries, since the rate of precession is generally much longer than the orbital period of the inner binary.
MAXI observations of long-term X-ray activities in SFXTs
Authors: Negoro Hitoshi
Published: December 2019

Supergiant Fast X-ray Transients (SFXTs) are of great interest not only because of their peculiar properties but also as possible progenitors of gravitational-wave objects. The all-sky X-ray monitor MAXI/GSC has detected short flares on timescales of hours and long flares on timescales of days from SFXTs. Using nine-years of MAXI/GSC data, I attempted to search periodicity of eight SFXTs of which the one-day average fluxes were below the detection limit (∼ 10 mCrab), and confirmed the orbital periods of IGR J18483–0311 and IGR J17544–2619. This demonstrates that MAXI data are useful to find periodicities of sources even if the sources are undetectable in one day.
Optical and X-ray study of V404 Cyg during its activity in the Summer 2015
Authors: Nikolaeva Evgeniya A. , Bikmaev Ilfan F. , Glushkov Maxim V. , Irtuganov Eldar N. , Khamitov Irek M.
Published: December 2019

. The black hole X-ray binary V404Cyg was studied during of the 2015 outburst. Optical photometry and spectroscopy were performed by using 1.5-meter Russian-Turkish telescope (RTT-150) facilities at the TUBITAK National Observatory (Antalya, Turkey). From June 22 to June 28, 2015, shell expansion velocity decreased from 650 to 400 km s–1 as measured by Hα and Hβ lines and from 450 to 330 km s–1 as measured by HeI and HeII lines. Thus, the shell expansion occurred with deceleration, where the hydrogen and helium line formation regions are at different radial distances from the center of the star. The correlation of flow variability in the optical and X-ray ranges is caused by fluctuations in the rate of accretion near a compact source where X-ray photons are generated.