bluuebunny/crossref_metadata_2025 huggingface dataset:
Postoperative Management of Vascular Surgery Patients and Complications
Authors: Rabai Ferenc , Cooper Michol A. , Covington Derek B.
Published: May 2021

Vascular surgery carries an increased risk of a variety of complications in the immediate and extended postoperative periods. Major vascular operations, such as thoracoabdominal aortic aneurysm repairs and limb revascularizations, are commonly associated with prolonged operative time, ischemic reperfusion injuries, large blood losses, and systemic inflammatory response syndrome. Additionally, vascular patients usually present with a high burden of comorbidities. These factors increase the risk of multiple organ systems failing postoperatively. Myocardial injury, postoperative pulmonary complications, acute kidney injury, and neurovascular complications are relatively common and have been shown to increase morbidity and mortality. Close monitoring and an appropriate level of care ensure a safe transition into the postoperative phase. Recent data suggest that risk stratification with modern diagnostic tools and laboratory tests using sensitive biomarkers play pivotal roles in the early detection of deteriorating organ function and initiation of timely intervention. Evidence-based postoperative management guidelines and care bundles (e.g., prehabilitation, enhanced screening for myocardial injury, lung-protective ventilator management, kidney protection strategies, and enhanced recovery protocols) show promise in preventing, mitigating, and effectively treating complications with an overarching goal of optimizing postoperative outcomes and ensuring that patients recover successfully.
Thoracic Radiology
Authors: Freels Parker D. , Wynn Gregory C. , Meyer Travis , Giuratrabocchetta Giuseppe
Published: May 2021

Diagnostic imaging plays an important role in patient care and management. Particularly in the procedural setting, the likelihood of a patient receiving some form of perioperative imaging is high. Therefore, the anesthesiologist should be familiar with the various available radiologic tools, their proper utilization, and the common imaging findings. These diagnostic imaging techniques allow clinicians the opportunity to gain insight into a patient’s unique anatomy and, based on these findings, prepare for a more appropriate patient-centered course of treatment based on these findings. Thoracic radiology is an extensive subject with a long list of potential pathology that can occur within the chest. In this chapter, the authors’ goal is to review the more routinely used imaging modalities (radiography, computed tomography, and ultrasonography) while focusing on some of the most common diseases, disorders, and defects of the thorax encountered by anesthesiologists during their daily practice. These include abnormalities of the airways, lungs, pleura, vasculature, and esophagus.
Physiology of One-Lung Ventilation
Authors: Shanmugam Geetha , Pla Raymond
Published: May 2021

Ventilation and perfusion are matched under physiologic conditions for optimal gas exchange and oxygenation. Ventilation involves the entry and exit of air from the lungs, while perfusion involves the flow of blood through alveolar pulmonary capillaries. Both are necessary for the diffusion of oxygen into and carbon dioxide out of the bloodstream. During thoracic surgery, the ventilation/perfusion (V/Q) relationship is disrupted by induction of general anesthesia, lateral decubitus positioning, one-lung ventilation, and the open chest. Despite ventilation/perfusion alterations, severe hypoxia is usually avoided with the aid of several intrinsic and extrinsic factors. This chapter will delve into the changing V/Q relationship that occurs during thoracic surgery; modifying factors, including hypoxic pulmonary vasoconstriction and position, among others; and strategies to address hypoxia intraoperatively.
Bronchoscopic Anatomy
Authors: Panjeton Geoffrey D. , Kirk Fowler W. , Panjeton Hess , Deng Yi , White Jeffrey D.
Published: May 2021

A functional understanding of normal tracheobronchial anatomy as well as its clinically relevant variations is essential to effective, safe perioperative anesthetic evaluation and management for thoracic procedures. This chapter reviews the anatomy of the airway and lung structures that are encountered during basic bronchoscopy. The larynx, trachea, and tracheobronchial tree, including right and left lung and bronchial anatomy and vascular supply to the trachea and bronchial tree, are presented in addition to key identifying features for each structure. Labeled illustrations and bronchoscopic images are provided for reference and clarity. The vascular supply is also described and depicted. This chapter includes possible anatomical and pathological variants that may be discovered during bronchoscopy.
Visit 3
Authors: Ferguson Robert J. , Gillock Karen Lee
Published: May 2021

In this visit, survivors review their practice and response to quick relaxation, and their overall ability to use relaxation skills in daily life. They also review their use of self-instructional training, review homework, and discuss any other memory and attention problems they’ve noticed. Visit 3 involves reviewing verbal rehearsal strategies (verbal rehearsal, spaced rehearsal, chunking, and rhymes) and selecting one to focus on. The survivor learns how to identify and challenge thinking that leads to excessive stress or erodes their emotional strength and resilience (use of probability estimation and Decatastrophizing). They will also practice the new memory and attention strategy and identify how and where it will be best applied and used in daily activity.
Visit 6
Authors: Ferguson Robert J. , Gillock Karen Lee
Published: May 2021

In Visit 6, survivors are introduced to combined internal and external strategies: active listening and verbal rehearsal for socializing. Active listening is a compensatory strategy used in MAAT to help reduce social avoidance due to cognitive difficulties. Active listening involves using basic interviewing methods, such as summarizing and clarifying what one heard, so that survivors can compensate for parts of conversation they may miss. It presents an opportunity to clarify and “verbally rehearse” the conversational point to register and remember. Verbal rehearsal also provides a strategy to help become re-engaged in previously avoided social activity. Three steps can be taken to aid with active listening skills: (1) review nonverbal behaviors and paralinguistic tone; (2) review summarization (when the listener repeats back a summary of what it is they believed they heard, thus rehearsing the message); and (3) review clarification to seek assurance that what was heard was the intended message. Further, fatigue management and sleep improvement are highlighted if relevant to the survivor, with the rationale of using simple behavior change to minimize the potential impact of sleep problems and fatigue on cognitive function.
Visit 8
Authors: Ferguson Robert J. , Gillock Karen Lee
Published: May 2021

In this last visit, the first part of the visit involves a review of visualization strategies, which ones were used and in which situations. The survivor and clinician then work together to form a maintenance plan that will help the survivor to continue to apply and refine MAAT compensatory and coping strategies. Emphasis is not on the end of MAAT, but “the end of the beginning.” A review of all compensatory strategies learned to date is completed and are detailed on how they will be applied in daily life in the maintenance plan. The survivor also identifies a plan for continued review of the MAAT Survivor Workbook and a source of social support in order that compensatory strategies continue to be applied and refined over the course of his or her lifetime. The intent is to maintain continued memory skills building and adaptations through life.
Visit 2
Authors: Ferguson Robert J. , Gillock Karen Lee
Published: May 2021

In Visit 2, the clinician sets the frame for homework by following up on assignments from Visit 1 without being punitive about tasks that were not done. Rather, the clinician reinforces progress/successes and brainstorms corrective actions. A review of self-monitoring worksheets should assist in identifying themes in memory and attention failures (e.g., verbal-auditory, visual-attention, recall of written or auditory information, ability to follow instruction) while acknowledging the role of environmental factors and inner physical and emotional states (e.g., anxiety, frustration, fatigue, hunger, pain). A review of progressive muscle relaxation sets the stage for learning quick relaxation. The important internal strategy of self-instructional training is introduced.
Visit 8
Authors: Ferguson Robert J. , Gillock Karen Lee
Published: May 2021

In Visit 8, the last MAAT visit, the clinician emphasizes the theme of maintaining continuous mastery and refinement of MAAT principles and adaptive skills going forward in life. Visit 8 begins with a review of visualization and the degree to which visualization methods are useful and practical for the survivor. After discussion about specific experiences with visualization (modifying as necessary), discussion is turned to developing a plan to maintain the new behaviors and attitudes toward self-managing CRCI in daily life. Emphasis is placed on the notion that MAAT is not completed; rather, Visit 8 represents “the end of the beginning.” Continuous application and use of MAAT compensatory strategies will become more routine with time, and this requires maintenance of awareness and use. Cognitive performance failures will likely wax and wane due to numerous factors, including the chronic nature of CRCI. Constructing the maintenance plan entails reviewing each of the adaptive strategies with the survivor and completing a provided form. In addition, the clinician and survivor identify a schedule of at least monthly review of the survivor workbook to help maintain and adapt MAAT skills with changes in life. They also identify sources of social support to help the survivor maintain consistency. Finally, the clinician and survivor may identify a schedule of follow-up or “booster” visits to reinforce maintenance.
Obesity
Authors: Saxena Bhavna , Sinha Ashish C.
Published: May 2021

This chapter explores the physiology and pathophysiology of obesity and provides an overview of its medical management. In spite of recognizing the medical problems associated with obesity, it was 2013 when the American Medical Association acknowledged it as a disease; thereafter, medical societies began treating it as such. Understanding body weight regulation requires an understanding of energy balance. There are three main factors that affect and maintain energy balance and a steady body weight—the homoeostatic, environmental, and behavioural processes. Alterations in any of these may lead to weight changes. Although weight loss can usually be achieved through restriction of caloric intake and/or increased physical activity, most individuals have a tendency to regain the lost weight. A plausible hypothesis is that body weight is maintained at a particular set level, and deviations from this set point are resisted and minimized by a feedback control system. Diet, exercise, and behavioural modifications should be all parts of obesity management, with adjunctive pharmacotherapy as necessary. In patients with extreme obesity, however, bariatric surgery is the best alternative treatment.
Cardiorespiratory physiology including airway changes in obesity
Authors: Porhomayon Jahan , Papadakos Peter J.
Published: May 2021

Obese patients may present for an elective procedure, for bariatric surgery, for emergency surgery, or for obstetric anaesthesia or analgesia. The anaesthesiologist and surgical personnel are routinely involved in the care of obese surgical patients. It is therefore necessary to understand the complex physiology of this group of patients and respond appropriately to manage this population. Additional, special equipment is often necessary and its availability and use must be planned in advance. Preoperative assessment and preparation, anaesthesia technique, patient positioning, and postoperative care all require special consideration and differ qualitatively as well as quantitatively.
Thoracoabdominal surgeries in obese patients
Authors: Ushakumari Deepu S. , Callison Stephanie Rayos
Published: May 2021

Obesity carries a unique set of physiological changes and increased risks that impact thoracic surgery. Obese patients have reductions in expiratory reserve volume and functional residual capacity, decreased lung and chest wall compliance, and increased work of breathing. Preoperative assessment should include evaluation for signs of difficult airway management and review of studies assessing pre-thoracotomy respiratory function. Invasive lines may be required in addition to standard American Society of Anesthesiologists monitors. Positive pressure ventilation, optimal positioning, and passive oxygen may assist in adequate preoxygenation before induction. Lung isolation may be achieved via double-lumen tube or bronchial blocker placement through a single-lumen tube, or via exchange to a double-lumen tube. Lateral decubitus positioning can be challenging and carries a risk of brachial plexus injury. Hypoxaemia during one-lung ventilation may be managed with continuous positive airway pressure, positive end-expiratory pressure, or periodic re-inflation of specific lungs. Thoracic epidural analgesia or paravertebral block may assist postoperative pain management. Hypoxaemia, dysrhythmias, haemorrhage, and acute kidney injury must be monitored for postoperatively.
Obesity and anaesthesia for spine and neurosurgery
Authors: Tewari Anurag , Ghazanwy Mahmood , Ayrian Eugenia
Published: May 2021

Obesity has nearly doubled in the world since 1980. Obesity is a common, serious, and costly problem. More than 10% of the world’s adult population is suffering from obesity. In 2009–2010, more than one-third of adults in the United States (35.7%) were obese. The prevalence of obesity is continuously increasing and causing problems in all aspects of healthcare including anaesthesiology. Obesity is an energy imbalance and is linked with increased morbidity and mortality and associated with a wide spectrum of medical and surgical issues. Fat-containing intracranial tumours and developmental lesions such as lipomas, dermoid and epidermoid cysts, and teratomas are common. An increased prevalence of obesity in patients undergoing craniotomy for meningiomas suggests an increased incidence of meningiomas in obese men. In this chapter, physiological changes associated with obesity, pharmacology, and the anaesthetic considerations and challenges for spine and neurosurgery are addressed.
Outcomes in bariatric surgery
Authors: Mekel Gabriel , Renza-Stingone Elizabeth , Castellanos Andres
Published: May 2021

Multiple procedures have been developed since the early beginnings of bariatric surgery in the 1950s. Some outcome measures used to evaluate success in bariatric surgery include percentage of excess weight loss, length of hospital stay, and resolution of comorbid diseases such as diabetes mellitus, hypertension, dyslipidaemia, and obstructive sleep apnoea. Surgery is considered successful for an individual patient if he or she loses more than 50% of their excess weight and resolves preoperative comorbid conditions.
Perioperative analgesia
Authors: Mangla Dipty
Published: May 2021

Postoperative pain remains a major cause of patient dissatisfaction and increased hospital costs. Obese patients with their increased sensitivity to narcotics and poor wound healing mechanisms are at a greater risk than non-obese individuals having a similar surgical procedure. The aims of this chapter are to understand the mechanism of pain, identify patients at risk of developing chronic pain, and realize the need of interdisciplinary pain management teams using multimodal pain management. The multimodal pain management approach includes oral analgesics, intravenous drugs, infiltrations, regional anaesthesia, and nerve blocks.
Postoperative complications in the obese patient and their management
Authors: Bowman Sara , Moonesinghe S. R.
Published: May 2021

This chapter discusses surgical, medical, and management challenges faced by the clinicians involved in the care of obese or bariatric surgical patients in the postoperative period. Obesity itself is an independent risk factor for postoperative morbidity and mortality. This is, in part, due to the direct impact of obesity and also to the increased prevalence of comorbidities in obese patients, including cardiovascular, respiratory, and endocrine disease, all of which may also be independently associated with adverse outcomes. More specifically, with the worldwide increase in obesity and increasing evidence of their benefits, greater numbers of weight loss operations are being undertaken, most commonly, laparoscopic gastric bypass or sleeve gastrectomy procedures. Surgery is commonly undertaken in specialist centres and length of stay is generally short; therefore, these patients may present with late complications at non-specialist hospitals, where general surgeons, anaesthetists, or physicians may not be familiar with the techniques of bariatric surgery. Thus, generalists may be faced with the management of acute or chronic complications of weight reduction surgery in an emergency setting and therefore an understanding of the surgery and the care of the obese patient is important for subsequent management.
Fluid management in the obese patient
Authors: Cole Michelle , Gilhooly David , Moonesinghe S. R.
Published: May 2021

Fluid management is a fundamental aspect of safe perioperative care for any surgical patient. This can present with several challenges when applied in the obese surgical patient, mainly because of differences in baseline fluid homeostasis and physiological responses to fluid administration, when compared to the non-obese patient. Obese patients often have cardiorespiratory dysfunction whereby their physiological responses to hypervolaemia or hypovolaemia can lead to further pathology. As such, the threshold for perioperative echocardiography should be lower in obese patients to fully evaluate the dynamic cardiovascular changes to fluid imbalance. Despite the challenges in terms of volume and rate of fluid administration in obese patients, the principles of fluid maintenance remain the same as one would adopt in the non-obese population. The nature of the fluid loss determines whether a resuscitative or maintenance approach is adopted, together with the type of fluid used, be that crystalloids, colloids, or blood products.
Cutaneous involvement and management of Sjögren’s syndrome
Authors: Tull Thomas J , Benton Emma , D’Cruz David
Published: May 2021

Primary Sjögren’s syndrome (SS) is an autoimmune condition characterized by sicca symptoms affecting mucosal surfaces with or without a spectrum of systemic manifestations. The skin acts as a remarkable window for the diagnosis of systemic autoimmune disease. SS has many diverse cutaneous manifestations, which occur in approximately 16% of patients, making skin involvement one of the most common extra-glandular manifestations of the disease. However, cutaneous manifestations of SS remain understudied. The most common cutaneous manifestations of SS are thought to be xerosis, cutaneous vasculitis, and annular erythema, the clinical and histopathological of which will be described in the chapter. Clinicians managing patients with SS should be mindful that cutaneous manifestations, such as purpura, are an important sign of systemic complications of the disease. It is therefore important for clinicians to undertake a full skin examination at each clinic visit.
Musculoskeletal disease—presentation and management
Authors: Price Elizabeth J.
Published: May 2021

Musculoskeletal manifestations are amongst the commonest extra-glandular manifestations seen in Sjögren’s syndrome (SS), affecting over half of patients. Arthralgia (joint pain without signs of inflammation) is a common manifestation (> 50%), with arthritis (joint pain with clinically detectable inflammation) being present in 16%. The arthritis is predominantly peripheral, symmetrical, polyarticular, and intermittent. Metacarpophalangeal, proximal interphalangeal joints, and wrists are the most commonly affected. It is usually nondeforming and nonerosive, and synovitis, when present, is generally mild and may be subclinical but detected on ultrasonography. In up to 20% the joint symptoms precede the diagnosis, in about 50% they are coincident with the diagnosis, and in 30% they occur later. Raynaud’s affects between a third and half of patients with SS. Although myalgia is common, myositis is rare. Chronic pain and fatigue are common.
Fatigue in Sjögren’s syndrome
Authors: Yeoh Su-Ann , Ciurtin Coziana
Published: May 2021

Fatigue is a common symptom described by people with Sjögren’s syndrome. There are different patterns of fatigue, and people with Sjögren’s syndrome may experience tiredness of a different nature compared to a healthy individual. The aetiology of fatigue is not fully understood and is likely to be multifactorial. There are a number of fatigue outcome measures and disease-activity scores used to assess and monitor fatigue. We discuss pharmacological therapies which have been studied in the context of fatigue and allude to nonpharmacological interventions to address fatigue. We also highlight the importance of incorporating assessment of fatigue due to the significant impact on the quality of life of patients and their abilities to carry out activities of daily living.
Post-operative breathlessness
Authors: Robinson Chapman
Published: May 2021

The respiratory physician is often asked to see patients who have become dyspnoeic following an operative procedure. The risk of pulmonary complications is greatest with thoracic or upper abdominal surgery, when a degree of respiratory dysfunction and consequent breathlessness due to atelectasis is inevitable. Always rule out upper airway obstruction.
Pregnancy and breathlessness
Authors: Robinson Chapman
Published: May 2021

Elevated serum progesterone levels stimulate respiratory drive and lead to an increased tidal volume and raised minute ventilation, with only a modest increase in O2 consumption. Any cause of maternal hypercapnia leads quickly to foetal respiratory acidosis. Elevation of the diaphragm occurs due to the enlarging uterus, leading to a reduced functional residual capacity (FRC). Raised levels of coagulation factors and impaired fibrinolysis, combined with venous stasis, result in a significantly increased risk of venous thromboembolism (VTE). Upper airway oedema, particularly in the setting of pre-eclampsia, may predispose to upper airway obstruction during sleep, but rarely frank OSA. OSA tends to occur in obese women and may be associated with impaired foetal growth and pre-eclampsia. Snoring in pregnancy is a poor predictor of OSA.
Preoperative assessment
Authors: Robinson Chapman
Published: May 2021

The respiratory physician may be asked to assess a patient prior to elective or emergency surgery. These patients are usually those with pre-existing respiratory disease such as COPD. Patients are now often also referred to respiratory units following positive screening for OSA. The usual functional status of the patient should be determined. Their respiratory function should be optimized, if possible, with medication changes where appropriate. In those with confirmed OSA pre-operative CPAP should be considered. These patients may require ventilatory support post-operatively. Ultimately, the decisions regarding fitness for surgery rest with the surgeon and the anaesthetist.
Paediatric lung disorders
Authors: Robinson Chapman
Published: May 2021

Includes: Chronic lung disease of prematurity, viral wheeze and asthma, congenital abnormalities, transition.
Rare lung diseases
Authors: Robinson Chapman
Published: May 2021

Includes: Pathophysiology, classification, and lung involvement of alveolar microlithiasis and amyloidosis, hereditary haemorrhagic telangiectasia, idiopathic pulmonary haemosiderosis, Langerhans cell histiocytosis, clinical features, diagnosis, and management of lymphangioleiomyomatosis (LAM), primary ciliary dyskinesia (PCD), pathophysiology, clinical features, and diagnosis and treatment of pulmonary alveolar proteinosis (PAP), aetiology, diagnosis, management, and complications of pulmonary arteriovenous malformations (PAVMs), and recurrent respiratory papillomatosis.
Respiratory infection—parasitic
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Includes: Pulmonary hydatid disease, amoebic pulmonary disease, pulmonary ascariasis, strongyloidiasis, toxocariasis, dirofilariasis, schistosomiasis, paragonimiasis, tropical (filarial) pulmonary eosinophilia.
Vasculitis and the lung
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Includes: Granulomatosis with polyangiitis (Wegener’s): presentation and diagnosis, management, microscopic polyangiitis, anti-glomerular basement membrane disease (Goodpasture’s), eosinophilic granulomatosis with polyangiitis (Churg–Strauss syndrome), rare pulmonary vasculitides,
Immunosuppressive drugs
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Immunosuppressive drugs are used mainly in the management of pulmonary vasculitis, but also in asthma, sarcoidosis, and ILD. The chapter also covers corticosteroids, azathioprine, methotrexate, cyclophosphamide, rituximab
Oxygen therapy
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Includes: Emergency oxygen therapy, home oxygen therapy, practical issues with home oxygen, long-term oxygen therapy (LTOT), ambulatory oxygen therapy (AOT), short burst oxygen therapy (SBOT)
Bronchoscopy
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Includes: Indications and risks, bleeding and bronchoscopy, patient preparation, bronchial washings, bronchial brushings, bronchial biopsies, bronchoalveolar lavage (BAL), transbronchial lung biopsy (TBB), central airway obstruction, diagnostic procedures, TBNA, EBUS, Radial EBUS, autofluorescence bronchoscopy, rigid bronchoscopy, navigation bronchoscopy, therapeutic procedures, bronchial laser resection, electrocautery, argon–plasma coagulation (APC), and cryotherapy/cryoextraction, photodynamic therapy (PDT), tracheobronchial stent insertion, and rachytherapy.
Chest drains
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Chest drain insertion is associated with significant morbidity and mortality, and careful consideration should be given to the precise indication for drainage. Out-of-hours drain insertion should be avoided, unless an emergency. Ultrasound guidance should be used for all drains inserted for fluid, but is not required for pneumothorax.
Cricothyroidotomy
Authors: Chapman Stephen J. , Robinson Grace V. , Shrimanker Rahul , Turnbull Chris D. , Wrightson John M.
Published: May 2021

Difficulty in intubating patients often arises unexpectedly, even in those predicted to be low risk. The Difficult Airway Society have produced guidelines to help planning for difficulty and to produce a standardized approach. Cricothyroidotomy or ‘emergency front of neck access’ is the Plan D on these guidelines. It should be performed in after plans A–C have failed, a situation termed ‘can’t intubate can’t oxygenate’ (CICO). Cricothyroidotomy should only be performed by those with appropriate skills and training. The descriptions in this chapter are included to describe the technique and to outline the equipment required.
Signalling Standards for Progress: Bridging the Divide Between a Valid Consent to Use Patient Data Under Data Protection Law and the Common Law Duty of Confidentiality
Authors: Dove Edward S , Taylor Mark J
Published: May 2021

In this article, we analyse the legal components of disclosing confidential patient information under the UK’s common law duty of confidentiality (CLDoC) and processing personal (health) data under the UK’s General Data Protection Regulation (GDPR) and Data Protection Act 2018. We describe the ostensible divide between the CLDoC and data protection law when it comes to the requirements of a valid signal of consent by a patient to use and disclose patient information, obtained by a health professional in the context of direct care, for health care and health research purposes. Ultimately, our analysis suggests that we are saddled, at least in the medium term, with two regimes operating with different standards of a valid consent—while putatively protecting similar interests. There is, however, opportunity for progress. It is possible to improve professional guidance on the interaction between the regimes and to achieve significant normative alignment without aligning the signalling standard for consent; this would promote consistent protection of reasonable expectations of patients across both regimes. Further coherence would require aligning not only the standard, but also the role played by consent under each regime. Here we argue that, in relation to direct care, any such shift should be away from consent as the normal justification. In relation to health research, on the contrary, it should be toward consent as the normal justification for use and disclosure of patient information under both the CLDoC and data protection law.
Galaxy formation with L-GALAXIES: modelling the environmental dependency of galaxy evolution and comparing with observations
Authors: Ayromlou Mohammadreza , Kauffmann Guinevere , Yates Robert M , Nelson Dylan , White Simon D M
Published: May 2021

We present a variation of the recently updated Munich semi-analytical galaxy formation model, L-Galaxies, with a new gas stripping method. Extending earlier work, we directly measure the local environmental properties of galaxies to formulate a more accurate treatment of ram-pressure stripping for all galaxies. We fully recalibrate the modified L-Galaxies model using a Markov Chain Monte Carlo (MCMC) method with the stellar mass function and quenched fraction of galaxies as a function of stellar mass at 0 ≤ z ≤ 2 as constraints. Due to this recalibration, global galaxy population relations, including the stellar mass function, quenched fractions versus galaxy mass, and H i mass function are all largely unchanged and remain consistent with observations. By comparing to data on galaxy properties in different environments from the SDSS and HSC surveys, we demonstrate that our modified model improves the agreement with the quenched fractions and star formation rates of galaxies as a function of environment, stellar mass, and redshift. Overall, in the vicinity of haloes with total mass 1012 to $10^{15}\, \rm M_{\odot }$ at z = 0, our new model produces higher quenched fractions and stronger environmental dependencies, better recovering observed trends with halocentric distance up to several virial radii. By analysing the actual amount of gas stripped from galaxies in our model, we show that those in the vicinity of massive haloes lose a large fraction of their hot halo gas before they become satellites. We demonstrate that this affects galaxy quenching both within and beyond the halo boundary. This is likely to influence the correlations between galaxies up to tens of megaparsecs.
Planet Hunters TESS III: two transiting planets around the bright G dwarf HD 152843
Authors: Eisner N L , Nicholson B A , Barragán O , Aigrain S , Lintott C , Kaye L , Klein B , Miller G , Taylor J , Zicher N , Buchhave L A , Caldwell D A , Horner J , Llama J , Mortier A , Rajpaul V M , Stassun K , Sporer A , Tkachenko A , Jenkins J M , Latham D , Ricker G , Seager S , Winn J , Alhassan S , Baeten E M L , Bean S J , Bundy D M , Efremov V , Ferstenou R , Goodwin B L , Hof M , Hoffman T , Hubert A , Lau L , Lee S , Maetschke D , Peltsch K , Rubio-Alfaro C , Wilson G M
Published: May 2021

We report on the discovery and validation of a two-planet system around a bright (V  = 8.85 mag) early G dwarf (1.43  R⊙, 1.15  M⊙, TOI 2319) using data from NASA’s Transiting Exoplanet Survey Satellite (TESS). Three transit events from two planets were detected by citizen scientists in the month-long TESS light curve (sector 25), as part of the Planet Hunters TESS project. Modelling of the transits yields an orbital period of $11.6264 _{ - 0.0025 } ^ { + 0.0022 }$ d and radius of $3.41 _{ - 0.12 } ^ { + 0.14 }$ R⊕ for the inner planet, and a period in the range 19.26–35 d and a radius of $5.83 _{ - 0.14 } ^ { + 0.14 }$ R⊕ for the outer planet, which was only seen to transit once. Each signal was independently statistically validated, taking into consideration the TESS light curve as well as the ground-based spectroscopic follow-up observations. Radial velocities from HARPS-N and EXPRES yield a tentative detection of planet b, whose mass we estimate to be $11.56 _{ - 6.14 } ^ { + 6.58 }$ M⊕, and allow us to place an upper limit of 27.5 M⊕ (99 per cent confidence) on the mass of planet c. Due to the brightness of the host star and the strong likelihood of an extended H/He atmosphere on both planets, this system offers excellent prospects for atmospheric characterization and comparative planetology.
Absorption spectra from the n = 3 manifold states of Li atoms in magnetic fields of white dwarfs
Authors: Zhao L B
Published: May 2021

The two-dimensional B-spline approach recently developed has been applied to calculations of absorption spectra from the n  = 3 manifold states of Li atoms in magnetic fields of white dwarfs. A total of 28 magnetized atomic states of five symmetries, 20±, 2(− 1)±, and 2(− 2)+, for this atomic system are involved in the current calculations. Wavelengths and oscillator strengths are presented for 60 transitions as a function of magnetic fields ranging from 2.35 to 2350 MG, typical of magnetic white dwarfs. Zeeman spectral lines of all these transitions lie in the region of ultraviolet, visible light, and infrared except for the six transitions, in which energy levels of the initial and final states are inversed at some magnetic field strength. Our results in the field-free case are compared to available data in the literature. Excellent agreement is observed between our spectral data and those from the NIST data base as well as the other theoretical calculations in the field-free case. The present spectral data are applicable to modelling discrete atomic spectral lines in the magnetic white dwarf atmospheres with lithium included.
Characterizing hydrostatic mass bias with mock-X
Authors: Barnes David J , Vogelsberger Mark , Pearce Francesca A , Pop Ana-Roxana , Kannan Rahul , Cao Kaili , Kay Scott T , Hernquist Lars
Published: May 2021

Surveys in the next decade will deliver large samples of galaxy clusters that transform our understanding of their formation. Cluster astrophysics and cosmology studies will become systematics limited with samples of this magnitude. With known properties, hydrodynamical simulations of clusters provide a vital resource for investigating potential systematics. However, this is only realized if we compare simulations to observations in the correct way. Here we introduce the mock-X analysis framework, a multiwavelength tool that generates synthetic images from cosmological simulations and derives halo properties via observational methods. We detail our methods for generating optical, Compton-y and X-ray images. Outlining our synthetic X-ray image analysis method, we demonstrate the capabilities of the framework by exploring hydrostatic mass bias for the IllustrisTNG, BAHAMAS, and MACSIS simulations. Using simulation derived profiles we find an approximately constant bias b ≈ 0.13 with cluster mass, independent of hydrodynamical method, or subgrid physics. However, the hydrostatic bias derived from synthetic observations is mass-dependent, increasing to b = 0.3 for the most massive clusters. This result is driven by a single temperature fit to a spectrum produced by gas with a wide temperature distribution in quasi-pressure equilibrium. The spectroscopic temperature and mass estimate are biased low by cooler gas dominating the emission, due to its quadratic density dependence. The bias and the scatter in estimated mass remain independent of the numerical method and subgrid physics. Our results are consistent with current observations and future surveys will contain sufficient samples of massive clusters to confirm the mass dependence of the hydrostatic bias.
A first glimpse at the Galactic plane with the ASKAP: the SCORPIO field
Authors: Umana G , Trigilio C , Ingallinera A , Riggi S , Cavallaro F , Marvil J , Norris R P , Hopkins A M , Buemi C S , Bufano F , Leto P , Loru S , Bordiu C , Bunton J D , Collier J D , Filipovic M , Franzen T M O , Thompson M A , Andernach H , Carretti E , Dai S , Kapińska A , Koribalski B S , Kothes R , Leahy D , Mcconnell D , Tothill N , Michałowski M J
Published: May 2021

In the broad context of the Australian Square Kilometer Array Pathfinder (ASKAP) early-science phase and preparation for the related surveys, we report the first radio observations towards the Galactic plane. The targeted field was chosen to encompass the entire SCORPIO survey, one of the several pathfinder projects for the Evolutionary Map of the Universe survey planned with the ASKAP. The observations were carried out in 2018 January at a central frequency of 912 MHz, with 15 operational antennas, and covered a total area of about 40 square degrees in three different pointings. The final image has a resolution of 24.1 × 21.1 arcsec2 and a median rms of $541\ \mu \mathrm{Jy\ beam}^{-1}$. We were able to extract 3545 candidate sources, 75 per cent of them point sources. For a preliminary validation, a comparison with the 843 MHz Molonglo Galactic Plane Survey is presented. Although the present observations were obtained with the ASKAP only partially deployed, its unique capability to map complex sources, such as those inhabiting the Galactic plane, at different angular scales, is highlighted. Within the SCORPIO field all the previously classified H ii regions, Planetary Nebulae (PNe), and supernovae remnants (SNRs), previously known to be radio sources, were detected. We also report new radio detections from several H ii regions previously classified as ‘candidates’ or ‘radio quiet’ and from half of all the PNe in the SCORPIO field with robust classification. Most notably, we find numerous unclassified, extended sources which constitute a promising sample of candidates H ii regions and SNRs.
Thermal instability in the CGM of L⋆ galaxies: testing ‘precipitation’ models with the FIRE simulations
Authors: Esmerian Clarke J , Kravtsov Andrey V , Hafen Zachary , Faucher-Giguère Claude-André , Quataert Eliot , Stern Jonathan , Kereš Dušan , Wetzel Andrew
Published: May 2021

We examine the thermodynamic state and cooling of the low-z circumgalactic medium (CGM) in five FIRE-2 galaxy formation simulations of Milky Way-mass galaxies. We find that the CGM in these simulations is generally multiphase and dynamic, with a wide spectrum of largely non-linear density perturbations sourced by the accretion of gas from the intergalactic medium (IGM) and outflows from both the central and satellite galaxies. We investigate the origin of the multiphase structure of the CGM with a particle-tracking analysis and find that most of the low-entropy gas has cooled from the hot halo as a result of thermal instability triggered by these perturbations. The ratio of cooling to free-fall time-scales tcool/tff in the hot component of the CGM spans a wide range of ∼1−100 at a given radius but exhibits approximately constant median values of ∼5−20 at all radii 0.1Rvir < r < Rvir. These are similar to the ≈10−20 value typically adopted as the thermal instability threshold in ‘precipitation’ models of the ICM. Consequently, a one-dimensional model based on the assumption of a constant tcool/tff and hydrostatic equilibrium approximately reproduces the number density and entropy profiles of each simulation but only if it assumes the metallicity profile and temperature boundary condition taken directly from the simulation. We explicitly show that the tcool/tff value of a gas parcel in the hot component of the CGM does not predict its probability of subsequently accreting on to the central galaxy. This suggests that the value of tcool/tff is a poor predictor of thermal stability in gaseous haloes in which large-amplitude density perturbations are prevalent.
The H i and stellar mass bivariate distribution of centrals and satellites for all, late-, and early-type local galaxies
Authors: Calette A R , Avila-Reese Vladimir , Rodríguez-Puebla Aldo , Lagos Claudia del P , Catinella Barbara
Published: May 2021

We characterize the conditional distributions of the H i gas-to-stellar mass ratio, $\mbox{$R_{\rm H\,\rm{i}}$}\equiv \mbox{$M_{\rm H\,\rm{i}}$}/\mbox{$M_{\ast }$}$, given the stellar mass, M*, of local galaxies from M* ∼ 107–1012 M⊙ separated into centrals and satellites as well as into late- and early-type galaxies (LTGs and ETGs, respectively). To do so, we use (1) the homogeneous ‘eXtended GALEX Arecibo SDSS Survey’, xGASS (Catinella et al. 2018), by re-estimating their upper limits and taking into account them in our statistical analysis; and (2) the results from a large compilation of H i data reported in Calette et al. (2018). We use the $R_{\rm H\,\rm{i}}$ conditional distributions combined with the Galaxy Stellar Mass Function to infer the bivariate $M_{\rm H\,\rm{i}}$ and M* distribution of all galaxies as well of the late/early-type and central/satellite subsamples and their combinations. Satellites are on average less H i gas-rich than centrals at low and intermediate masses, with differences being larger for ETGs than LTGs; at M* > 3−5 × 1010 M⊙ the differences are negligible. The differences in the H i gas content are much larger between LTGs and ETGs than between centrals and satellites. Our empirical H i Mass Function is strongly dominated by central galaxies at all masses. The empirically constrained bivariate $M_{\rm H\,\rm{i}}$ and M* distributions presented here can be used to compare and constrain theoretical predictions as well as to generate galaxy mock catalogues.
Black hole magnetic fields and their imprint on circular polarization images
Authors: Ricarte Angelo , Qiu Richard , Narayan Ramesh
Published: May 2021

The circular polarization of black hole accretion flows can encode properties of the underlying magnetic field structure. Using general relativistic magnetohydrodynamic (GRMHD) simulations, we study the imprint of magnetic field geometry on circular polarization images potentially observable by the Event Horizon Telescope (EHT). We decompose images into the different mechanisms that generate circular polarization in these models that are sensitive to both the line-of-sight direction and twist of the magnetic field. In these models, a stable sign of the circular polarization over time, as observed for several sources, can be attributed to a stability of these properties. We illustrate how different aspects of a generic helical magnetic field geometry become imprinted on a circular polarization image. We also identify novel effects of light bending that affect the circular polarization image on event horizon scales. One consequence is the sign flipping of successive photon rings in face-on systems, which if observable and uncorrupted by Faraday rotation, can directly encode the handedness of the approaching magnetic field.
A scaling relation for the molecular cloud lifetime in Milky Way-like galaxies
Authors: Jeffreson Sarah M R , Keller Benjamin W , Winter Andrew J , Chevance Mélanie , Kruijssen J M Diederik , Krumholz Mark R , Fujimoto Yusuke
Published: May 2021

We study the time evolution of molecular clouds across three Milky Way-like isolated disc galaxy simulations at a temporal resolution of 1 Myr and at a range of spatial resolutions spanning two orders of magnitude in spatial scale from ∼10 pc up to ∼1 kpc. The cloud evolution networks generated at the highest spatial resolution contain a cumulative total of ∼80 000 separate molecular clouds in different galactic–dynamical environments. We find that clouds undergo mergers at a rate proportional to the crossing time between their centroids, but that their physical properties are largely insensitive to these interactions. Below the gas–disc scale height, the cloud lifetime τlife obeys a scaling relation of the form τlife∝ℓ−0.3 with the cloud size ℓ, consistent with over-densities that collapse, form stars, and are dispersed by stellar feedback. Above the disc scale height, these self-gravitating regions are no longer resolved, so the scaling relation flattens to a constant value of ∼13 Myr, consistent with the turbulent crossing time of the gas disc, as observed in nearby disc galaxies.
The interplay between ambipolar diffusion and Hall effect on magnetic field decoupling and protostellar disc formation
Authors: Zhao Bo , Caselli Paola , Li Zhi-Yun , Krasnopolsky Ruben , Shang Hsien , Lam Ka Ho
Published: May 2021

Non-ideal magnetohydrodynamic (MHD) effects have been shown recently as a robust mechanism of averting the magnetic braking ‘catastrophe’ and promoting protostellar disc formation. However, the magnetic diffusivities that determine the efficiency of non-ideal MHD effects are highly sensitive to microphysics. We carry out non-ideal MHD simulations to explore the role of microphysics on disc formation and the interplay between ambipolar diffusion (AD) and Hall effect during the protostellar collapse. We find that removing the smallest grain population (≲10 nm) from the standard MRN size distribution is sufficient for enabling disc formation. Further varying the grain sizes can result in either a Hall-dominated or an AD-dominated collapse; both form discs of tens of au in size regardless of the magnetic field polarity. The direction of disc rotation is bimodal in the Hall-dominated collapse but unimodal in the AD-dominated collapse. We also find that AD and Hall effect can operate either with or against each other in both radial and azimuthal directions, yet the combined effect of AD and Hall is to move the magnetic field radially outward relative to the infalling envelope matter. In addition, microphysics and magnetic field polarity can leave profound imprints both on observables (e.g. outflow morphology, disc to stellar mass ratio) and on the magnetic field characteristics of protoplanetary discs. Including Hall effect relaxes the requirements on microphysics for disc formation, so that prestellar cores with cosmic ray ionization rate of ≲2–3 × 10−16 s−1 can still form small discs of ≲10 au radius. We conclude that disc formation should be relatively common for typical prestellar core conditions, and that microphysics in the protostellar envelope is essential to not only disc formation, but also protoplanetary disc evolution.
Kepler’s Goat Herd: An exact solution to Kepler’s equation for elliptical orbits
Authors: Philcox Oliver H E , Goodman Jeremy , Slepian Zachary
Published: May 2021

A fundamental relation in celestial mechanics is Kepler’s equation, linking an orbit’s mean anomaly to its eccentric anomaly and eccentricity. Being transcendental, the equation cannot be directly solved for eccentric anomaly by conventional treatments; much work has been devoted to approximate methods. Here, we give an explicit integral solution, utilizing methods recently applied to the ‘geometric goat problem’ and to the dynamics of spherical collapse. The solution is given as a ratio of contour integrals; these can be efficiently computed via numerical integration for arbitrary eccentricities. The method is found to be highly accurate in practice, with our C++ implementation outperforming conventional root-finding and series approaches by a factor greater than two.