Flare Rate Research Articles

Disease activity at conception predicts lupus flare up to two years after birth: A multicentre long term follow-up study

ObjectiveTo assess predicting factors that might influence systemic lupus erythematosus (SLE) disease activity in women in an extended follow-up period of two years after giving birth with clinical assessments every three months. MethodsThe study was design as an international retrospective study, enrolling 119 women with a first birth and with a two years follow-up. ResultsJoint involvement was present in 80% of patients, acute cutaneous in 64%, haematological in 54%, renal in 41% and 75% of patients were positive for anti-dsDNA. The mean SLE disease activity index 2000 (SLEDAI-2K) at diagnosis was 13.5±6.8 and at first birth was 2.8±4.4.At follow-up, 51.3% of patients had at least one flare after a mean time after birth of 9±6.3 months (mean flare per patient 0.94±1.1). The most frequent flare manifestations were joint involvement (48%), renal (33%), cutaneous (28%) and haematologic (20%).Patients with remission of disease (SLEDAI-2K=0; no clinical or laboratory manifestations of SLE) at conception had significantly lower rates of flares (18/49–37% vs. 43/70–61%; p=0.008).Patients who experienced a flare during pregnancy (17 patients) had higher rates of flares during follow-up (76% vs. 47%; p=0.019), lower time for first flare (4.4±2.3 months vs. 10.3±6.5; p<0.001), lower rate of remission of disease at conception (12% vs. 46%; p<0.001), lower rates of SLEDAI-2K at conception (5.9±5.6 vs. 2.3±4; p<0.001) and lower rates of exclusive breastfeeding (24% vs. 57%: p=0.009). Results were confirmed after performing multivariate analysis. ConclusionRemission at conception can influence SLE disease positively, even at long-term. Planned pregnancy counseling is fundamental when managing SLE patients.

There Is No Evidence That Inactivated COVID-19 Vaccines Increase Risks of Uveitis Flare.

This is a retrospective study to investigate the impact of inactivated Coronavirus disease-2019 (COVID-19) vaccination on uveitis flare in patients with uveitis. Sixty patients that were regularly followed up for uveitis for at least two months after the last dose of inactivated COVID-19 vaccines were included in the vaccination group. Sixty patients with comparable characteristics of uveitis who had not received the COVID-19 vaccines were included in the control group. Uveitis flare within 30 days and 60 days after the vaccination in the vaccination group, or after a randomly selected date in the control group, were statistically compared. The flare rate was 16.7% (30 days) and 23.3% (60 days) in the vaccination group, while it was 13.3% (30 days) and 25% (15/60) in the control group. There was no statistical difference in the flare rate of uveitis between the two groups (p = 0.471 for 30 days, p = 0.347 for 60 days). Inactivated COVID-19 vaccination appeared not to increase the flare rate in patients with uveitis. Ophthalmologists should give proper and individualized recommendations based on the overall conditions of patients.

Characterization of the NUV and optical emission and temperature of flares from Ross 733 with Swift and TESS

ABSTRACT We present the results of a coordinated campaign to simultaneously observe the M star binary Ross 733 in the optical and near-ultraviolet (NUV) with TESS and Swift, respectively. We observed two flares in the Swift NUV light curve. One of these was decay phase of a flare that was also detected with TESS and the other was only detected in the NUV. We used the TESS light curve to measure the white-light flare rate of Ross 733, and calculate that the system flares with an energy of 1033 erg once every 1.5 d. We used our simultaneous observations to measure a pseudo-continuum temperature of $7340^{+810}_{-900}$ K during the flare decay. We also used our observations to test the NUV predictions of the 9000 K blackbody flare model, and find that it underestimates number of flares we detect in our Swift NUV light curve. We discuss the reasons for this and attribute it to the unaccounted contributions from emission lines and continuum temperatures above 9000 K. We discuss how additional observations are required to break the degeneracy between the two in future multiwavelength flare campaigns.

Increased Relapse Rate During COVID-19 Lockdown in an Italian Cohort of Children With Juvenile Idiopathic Arthritis.

ObjectiveChanges of routine disease management associated with COVID‐19 lockdown might have potentially affected the clinical course of juvenile idiopathic arthritis (JIA). The aim of our study was to assess the rate of disease flare before and during COVID‐19 lockdown to investigate its impact on disease course in children with JIA.MethodsA single‐center retrospective study was conducted, including patients presenting with inactive JIA between September 1, 2018 and March 9, 2019 (group A) and between September 1, 2019 and March 9, 2020 (group B). For each patient, demographic and clinical data were collected. The rate of JIA flare from March 10, 2019 to June 30, 2019 for group A and from March 10, 2020 to June 30, 2020 for group B was compared.ResultsGroup A included 126 patients, and group B 124 patients. Statistical analysis did not show significant differences among the 2 cohorts with respect to age, sex, age at JIA onset, JIA subtype, co‐occurrence of uveitis, antinuclear antibody positivity, and past or ongoing medications. The rate of disease flare during lockdown at the time of the first COVID‐19 pandemic wave was significantly higher in comparison to the previous year (16.9% versus 6.3%; P = 0.009).ConclusionOur study showed that COVID‐19 lockdown was associated with a higher rate of joint inflammation in children with JIA. This finding has a considerable clinical implication, as restrictive measures may be necessary in order to contain pandemics. Our data highlight the need for rearrangement in the home and health care management of children with JIA during lockdowns.

S1369 Outcomes of Gout in Patients With Cirrhosis - A NIS-Based Study

Introduction: Hyperuricemia is a prerequisite for the development of gout. Elevated serum uric acid (UA) levels result from either overproduction or decreased excretion (whether by the kidneys or bowel). Some literary works denote a positive correlation between serum UA levels, cirrhosis-related complications and the incidence of non-alcoholic fatty liver disease. The exact relationship, whether hyperuricemia results in worsening cirrhosis outcomes or vice versa, is unknown. Despite these correlations, few studies explore the relationship between cirrhosis and gout. We aim to explore a possible link between them. Methods: The National Inpatient Sample (NIS) was used to identify patients hospitalized with gout, stratified based on a history of cirrhosis, from 2001 to 2013 via the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) codes. Primary outcomes consisted of mortality, gout complications (rates of flare, tophi formation, nephrolithiasis, nephropathy, and septic arthritis), and joint interventions (arthrocentesis and joint injection). Chi-squared and independent t-tests were done to assess categorical and continuous data, respectively. Multiple logistic regression was used to control for confounders, including age, sex at birth, race, cardiac arrhythmias, chronic pulmonary disease, heart failure, diabetes, HIV, HTN, peripheral vascular disease, alcohol use disorder and renal failure. Results: Patients without cirrhosis were older (70.37±13.53 years versus 66.21±12.325 years; p< 0.05). The majority of both groups were male, but cirrhotic patients had more males versus females (74.63% versus 66.83%; adjusted p=0.121). Cirrhotic patients had higher rates of mortality (5.49% versus 2.03%; adjusted p< 0.05), gout flare (2.89% versus 2.77%; adjusted p< 0.05) and tophi (0.97% versus 0.75%; adjusted p=0.677). Non-cirrhotic patients had higher rates of arthrocentesis (2.45% versus 2.21%; adjusted p< 0.05) and joint injections (0.72% versus 0.52%; adjusted p< 0.05). Rates of septic arthritis, nephropathy and uric acid nephrolithiasis did not differ significantly among both groups. Conclusion: Cirrhotics had greater incidence of gout-related complications, representing a possible link between cirrhosis and elevated average serum UA levels. Non-cirrhotics had higher rates of more invasive interventions, which could be due to clinician hesitancy with performing these interventions given increased bleeding risk in the setting of cirrhosis-related coagulopathy. (Table) Table 1. - Patient Characteristics and Differences in Inpatient Gout Outcomes in Individuals With and Without Cirrhosis Non-Cirrhotics Cirrhotics OR CI p-value AOR ACI Adjusted p-value Percentage n Percentage n Sex at birth Female 33.17 494,890 25.37 9,372 0.685 0.669-0.701 < 0.05 0.979 0.953-1.006 0.121 Male 66.83 996,939 74.63 27,576 Mortality 2.03 30,286 5.49 2,029 2.804 2.678-2.937 < 0.05 3.092 2.939-3.252 < 0.05 Gout Flare 2.77 41,282 2.89 1,066 1.044 0.982-1.11 0.171 0.816 0.765-0.871 < 0.05 Tophi 0.75 11,202 0.97 358 1.293 1.164-1.438 < 0.05 1.025 0.914-1.149 0.677 Uric Acid Nephrolithiasis 0.02 374 0.02 9 0.972 0.502-1.882 0.932 1.037 0.53-2.03 0.915 Nephropathy 0.02 283 0.01 5 0.713 0.295-1.727 0.452 0.548 0.223-1.346 0.19 Arthrocentesis 2.45 36,611 2.21 818 0.9 0.839-0.965 < 0.05 0.741 0.686-0.8 < 0.05 Joint Injection 0.72 10,673 0.52 192 0.725 0.628-0.837 < 0.05 0.713 0.61-0.833 < 0.05 Septic Arthritis 0.31 4,637 0.31 114 0.993 0.824-1.196 0.939 0.997 0.821-1.211 0.977 Mean SD SE Mean Mean SD SE Mean Mean difference CI p-value Age at admission (years) 70.37 13.53 0.011 66.21 12.325 0.064 4.167±0.071 4.027-4.306 < 0.05 n: sample size; OR: odds ratio; CI: 95% confidence interval; AOR: adjusted odds ratio; ACI: adjusted 95% confidence interval; SD: standard deviation; SE: standard error.

S963 Characteristics, Treatment and Outcome of Patients With Previously Diagnosed Autoimmune Disease After Immune Checkpoint Inhibitor Exposure

Introduction: Immune checkpoint inhibitors (ICI) can predispose to immune related adverse events (irAEs) and autoimmune disease (AD) flare-ups. irAE characteristics among patients with previously diagnosed AD have not been well studied. We aim to describe the clinical course, complications, treatment, and outcomes of patients with AD on ICIs. Methods: This is a retrospective chart review of adult cancer patients at the MD Anderson Cancer Center diagnosed with AD (based on ICD code) prior to the first dose of ICI treatment between 01/01/2010 and 04/30/2021. Patients’ clinical course, treatment and outcomes related to both AD and irAE were collected and analyzed. Results: A total of 197 patients were included in this study. A majority of our sample were female (55.4%) most frequently having melanoma (28.4%) and receiving PD-1/L1 inhibitors (83.7%). Forty-two patients (21.3%) developed a new irAE after starting immunotherapy, while 29 had an AD flare (14.7%). Patients with inflammatory bowel disease (IBD) had the highest rate of AD flare (31.7%), while patients with hypothyroidism had the highest incidence of new irAEs at 39.2%. Patients with IBD had more severe adverse events however with a median CTCAE grade of 3.5. In our cohort, all patients that were diagnosed with a new irAE were treated with immunosuppressive therapy. AD flares were managed similarly. With regards to irAE manifestations, colitis was the most common presentation in our cohort; at least 24 patients (23.2%) excluding those patients with a diagnosis of (IBD and microscopic colitis) had this type of complication. This was followed by pneumonitis in 9 patients (4.5%) and transaminitis in 7 patients (3.5%). Conclusion: Studies on the correlation between prior AD and immunotherapy are still lacking. Our findings suggest that patients with GI and rheumatologic ADs had higher incidence of AD flare up than new irAE development, while patients with thyroid and neurologic ADs appeared to have higher incidence of new irAEs compared to AD flare. Patients with prior AD experiencing a flare or a new irAE after immunotherapy tend to require more aggressive immunosuppressive treatment for symptom control. Thorough evaluation of baseline disease status, the appropriate medical management prior to ICI, and early recognition of inflammatory exacerbation could be key factors to ensure long-term success with treating and improving outcomes of these patients. Table 1. - Summary of irAE characteristics per Autoimmune Disease system, N=197 Autoimmune Disease per system Active AD status before ICI, N (%) On medical Rx before ICI, N (%) Flare up after ICI, N (%) Type of ICI Peak CTCAE grade of flare up (median, IQR) Required IMS for flare up, N (% of those that had flare) New irAE in different organ from AD, N (%) Peak CTCAE of irAE (median, IQR) IMS required for irAE, N (% of those that had irAE) Hematological ITP (N=2) 0 (0) 0 (0) 0 (0) PD1/L1=2 (100) N/A N/A 0 (0) N/A N/A Endocrine Hypothyroidism (N=51) 0 (0) 51 (100) 2 (3.9) Combined= 9 (17.6); PD1/L1=42 (82.3) Grade 2 in 1 (50) 0 (0) 20 (39.2) 2(1-3) 20 (100) Neurological MS-TM-GBS (N=27) 27 (100) 3 (11.1) 2 (7.4) Combined= 1 (3.8); PD1/L1= 21 (77.7); CTLA-4=5 (18.5) N/A 2 (100) 5 (18.5) 1(1-1.5) 5 (100) Rheumatological Rheumatoid A (N=58) 0 (0) 58 (100) 15 (25.8) Combined= 1 (1.7); PD1/L1= 57 (98.2); N/A 15 (100) 12 (20.6) 2.5(2-3) 9 (75) Gastroenterological (N=30) 0 (0) 30 (100) 10 (33.3) Combined=3 (10); PD1/L1=27 (90) N/A 10 (100) 5 (16.6) N/A 5 (100) Microscopic Colitis (N=10) 0 (0) 3(30) 8 (80) PD1/L1=10 (100) N/A 8 (100) 1 (10) N/A 1 (100) Celiac Disease (N=1) 0 (0) 0 (0) 0 (0) PD1/L1=1 (100) N/A N/A 0 (0) N/A N/A IBD (N=19) 1 (5.2) 10 (52.6) 6 (31.7) Combined=3 (15.7); PD1/L1=16 (84.2) N/A 6 (100) 4 (21) 3.5(3-4) 4 (100) Footnote: IMS=immunosuppressant. ITP=Immune Thrombocytopenic Purpura. MS=Multiple Sclerosis. TM= Transverse Myelitis. GBS=Guillain Barre Syndrome. IBD=Inflammatory Bowel Disease.*all the patients had baseline low activity at the time of ICI initiation. Flare up occurred when the symptoms progressed from baseline activity.

Safety and efficacy of the SGLT2 inhibitor dapagliflozin in patients with systemic lupus erythematosus: a phase I/II trial

ObjectiveSodium-glucose cotransporter-2 inhibitors have been identified profound renal/cardiac protective effects in different diseases. Here, we assessed the safety and efficacy of dapagliflozin among adult patients with systemic lupus erythematosus (SLE).MethodsWe...

A Pilot Survey of an M Dwarf Flare Star with Swift’s UV Grism

The near-ultraviolet (NUV) spectral region is a useful diagnostic for stellar flare physics and assessing the energy environment of young exoplanets, especially as relates to prebiotic chemistry. We conducted a pilot NUV spectroscopic flare survey of the young M dwarf AU Mic with the Neil Gehrels Swift Observatory's UltraViolet and Optical Telescope. We detected four flares and three other epochs of significantly elevated count rates during the 9.6 hr of total exposure time, consistent with a NUV flare rate of ∼0.5 hr−1. The largest flare we observed released a minimum energy of 6 × 1033 erg between 1730 and 5000 Å. All flares had durations longer than the ∼14–17 minutes duration of each Swift visit, making measuring total flare energy and duration infeasible.

Lupus low disease activity state as a treatment target for pediatric patients with lupus nephritis.

Lupus low disease activity state (LLDAS) is a treatment target for patients with SLE and is associated with decreased risk for severe flare and new damage. We investigated the utility of the achievement of LLDAS in children with lupus nephritis and whether attainment of LLDAS is associated with more favorable outcomes. Data of children, diagnosed with biopsy-proven lupus nephritis between January 2012 and December 2020, were retrospectively analyzed. For patients who did not achieve LLDAS after initial treatment (first 6months), presence of autoimmune hemolytic anemia (62% vs. 18%, p = 0.047), anti-Sm (85% vs. 18%, p = 0.003) and anti-dsDNA (77% vs. 27%, p = 0.038) antibodies, proliferative lupus nephritis (77% vs. 27%, p = 0.038), and hypertension (69% vs. 9%, p = 0.005) at onset were more frequently encountered. Also, a lower rate of complete kidney response (43% vs. 100%, p = 0.005) and a higher rate of hypertension (86% vs. 13%, p = 0.002) were observed in patients who did not achieve LLDAS-50, defined as being in LLDAS at least 50% of the observation time. Attainment of both LLDAS after initial treatment and LLDAS-50 were associated with lower rates of kidney flare (p = 0.001 and p = 0.002, respectively) and damage accrual (p = 0.007 and p = 0.02, respectively) through the observation period. LLDAS is an attainable treatment target for children with lupus nephritis and associated with lower rates of kidney flare and damage. Presence of hematologic involvement, hypertension, and proliferative lupus nephritis at onset adversely influenced the early achievement of LLDAS. A higher resolution version of the Graphical abstract is available as Supplementary information.

Predictors of infection requiring hospitalization in patients with systemic lupus erythematosus: a time-to-event analysis

ObjectivesTo evaluate the predictors of serious infection in patients with systemic lupus erythematosus (SLE). MethodsSerious infections were identified in SLE patients in a prospectively-followed single centre cohort. Associations of serious infection with disease-related variables and medication use were analysed using Cox and related regression models. Results346 patients were followed for a mean (SD) of 6.6 (3.7) years. 86 episodes of serious infection were observed, with an incidence rate of 3.8 episodes per 100 person-years. Patients who had serious infection had higher baseline SLE Damage Index (SDI) and Charlston Comorbidity Index (CCI); they were also more likely to have high disease activity status (HDAS), and higher disease activity in multiple clinical domains, higher flare rates, higher time-adjusted prednisolone dose exposure, and less time in lupus low disease activity state (LLDAS). Patients who have received cyclophosphamide, rituximab and mycophenolate were more likely to have experienced serious infection. After multivariable adjustment in Cox regression analysis, cyclophosphamide, higher SDI score, and higher disease activity were associated with an increased hazard of first serious infection. History of previous serious infection conferred the highest risk. Lymphopenia was also a modest but statistically significant predictor of serious infection. ConclusionHistory of previous serious infection was the strongest predictor of serious infection in our SLE cohort. This study also suggests that clinical factors such as damage accrual, disease activity, and choice of immunosuppressant, can each have an independent risk in predicting serious infection particularly the first episode.

Detectability of the gravitational-wave background produced by magnetar giant flares

We study the gravitational-wave background produced by f-mode oscillations of neutron stars triggered by magnetar giant flares. For the gravitational-wave energy, we use analytic formulae obtained via general relativistic magnetohydrodynamic simulations of strongly magnetized neutron stars. Assuming the magnetar giant flare rate is proportional to the star-formation rate, we show the gravitational-wave signal is likely undetectable by third-generation detectors such as the Einstein Telescope and Cosmic Explorer. We calculate the minimum value of the magnetic field and the magnetar giant flare rate necessary for such a signal to be detectable, and discuss these in the context of our current understanding of magnetar flares throughout the Universe.

Clustering Behavior in Solar Flare Dynamics

The solar magnetic activity cycle provides energy input that is released in intense bursts of radiation known as solar flares. As such, the dynamics of the activity cycle is embedded in the sequence of times between the flare events. Recent analysis shows that solar flares exhibit memory on different timescales. These previous studies showed that the time ordering of flare events is not random, but rather there is dependence between successive flares. In the present work, the clustering of flares is demonstrated through a straightforward nonparametric method where the cumulative distribution function of successive flares is compared with the cumulative distribution function of surrogate sequences of flares obtained by random permutation of flares. The random permutation is performed within rate-variable Bayesian blocks during which the flare rate is assumed to be constant. Differences between the cumulative distribution functions are substantial on a timescale around 3 hr, suggesting that flare recurrence on that timescale is more likely than would be expected if the waiting time were drawn from a nonstationary Poisson process.

Solar and Stellar Flares: Frequency, Active Regions, and Stellar Dynamo

We demonstrate that for weak flares the dependence of their frequency occurrence on spottedness can be rather weak. The fact is that such flares can occur in both small and large active regions. At the same time, powerful large flares of classes M and X occur much more often in large active regions. In energy estimates, the mean magnetic field in starspots can also be assumed to be equal to the mean field in the sunspot umbra. So the effective mean magnetic field is 900 Mx cm−2 in sunspots and 2000 Mx cm−2 in starspots. Moreover, the height of the energy storage cannot be strictly proportional to A 1/2. For stars, the fitting factor is an order of magnitude smaller. The analysis of the occurrence rate of powerful solar X-ray flares of class M and X and superflares on stars shows that, with allowance for the difference in the spottedness and compactness of active regions, both sets can be described by a single model. Thus, the problem of superflares on stars and their absence on the Sun is reduced to the problem of the difference in the effectiveness of the dynamo mechanisms.

Effect and safety profile of belimumab and tacrolimus combination therapy in thirty-three patients with systemic lupus erythematosus.

Belimumab combined with mycophenolate mofetil has been proven to be effective for treating systemic lupus erythematosus (SLE) in several randomized controlled trials. Calcineurin inhibitors are also useful in controlling the activity of SLE. However, the safety and effectiveness of belimumab-calcineurin inhibitor combination therapy have not been addressed. Therefore, the current single-center retrospective study aimed to analyze the safety/efficacy profile of belimumab-tacrolimus (B-T) combination therapy in patients with SLE. Patients with SLE administered tacrolimus and belimumab during treatment were included in the study. Samples were analyzed for the drug retention rate, SLE flare rate, infection incidence rate, and glucocorticoid-sparing effect of the B-T combination therapy. Thirty-three patients with SLE were treated with B-T combination therapy at our institution. Four patients discontinued treatment due to insufficient response or adverse events. The drug retention rate was over 90% at week 52 and approximately 80% at day 1000. Only one patient developed serious infection. The lupus low disease activity state (LLDAS) achievement ratio was 9.1% on the day of initiation and improved to 64.0% at 52weeks after initiation. SLE flares were observed in three patients (9.1%) in the first 52weeks after initiation, and in five patients (15.2%) throughout the study period. A glucocorticoid-reducing effect was also observed in patients treated with B-T combination therapy. In most patients with SLE, B-T combination therapy is well tolerated with a good efficacy profile and glucocorticoid-reducing effect. Thus, B-T combination therapy represents a feasible option for patients with refractory lupus. Key Points • The safety and effectiveness of belimumab-calcineurin inhibitor combination therapy have not been addressed. • The drug retention rate of belimumab-tacrolimus combination therapy was over 90% at week 52 and around 80% on day 1000 • Almost none of the patients suffered from severe infection after the initiation of belimumab-tacrolimus combination therapy. • Belimumab-tacrolimus combination therapy is efficacious in suppressing lupus activity and achieving LLDAS.

Managing ANCA-associated vasculitis during COVID-19 pandemic: a single-center cross-sectional study.

The objective of the study is to report the outcomes of COVID-19 in ANCA-associated vasculitis (AAV) patients. This was a registry-based observational study conducted at a tertiary care center in north India. AAV patients with at least one follow-up visit between March 2020 and September 2021 were included. Demographic features, clinical manifestations, disease activity, and treatment details of underlying AAV were noted in all patients. Details of COVID-19 infection including severity, treatment, and outcomes were noted. Predictors of COVID-19 severity were determined using univariate analysis. A total of 33 (18.3%) out of 180 AAV patients contracted COVID-19 infection. Moderate COVID-19 infection was seen in 33.3% and severe or critical infection was seen in 36.3% of patients. Seventeen patients (51.5%) required supplemental oxygen therapy. Nine patients had active disease at the time of COVID-19 infection and three of them died due to COVID-19 infection. The risk of COVID-19 infection and its severity did not differ between patients receiving different immunosuppressants including rituximab induction. Hypothyroidism (p = 0.046) and ocular (p = 0.038) involvement due to AAV predicted the development of moderate to severe/critical COVID-19. Three (9.1%) patients died from COVID-19 and the rate of AAV flare after COVID-19 was similar to that in non-COVID-19 patients (15.3/100 person-year vs. 15.6/100 person-year, p = 0.95). Majority of the patients with AAV had moderate to severe or critical COVID-19 infection. The rate of death due to COVID-19 in AAV is higher than in general population. Use of standard remission induction regimens did not lead to increased risk of COVID-19 infection in our AAV cohort.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00296-022-05177-2.

Galactic Kinematics and Observed Flare Rates of a Volume-complete Sample of Mid-to-late M Dwarfs: Constraints on the History of the Stellar Radiation Environment of Planets Orbiting Low-mass Stars

We present a study of the relationship between Galactic kinematics, flare rates, chromospheric activity, and rotation periods for a volume-complete, nearly all-sky sample of 219 single stars within 15 pc and with masses between 0.1 and 0.3 M ⊙ observed during the primary mission of TESS. We find all stars consistent with a common value of α = 1.984 ± 0.019 for the exponent of the flare frequency distribution. Using our measured stellar radial velocities and Gaia astrometry, we determine Galactic UVW space motions. We find 78% of stars are members of the Galactic thin disk, 7% belong to the thick disk, and for the remaining 15% we cannot confidently assign membership to either component. If we assume star formation has been constant in the thin disk for the past 8 Gyr, then based on the fraction that we observe to be active, we estimate the average age at which these stars transition from the saturated to the unsaturated flaring regime to be 2.4 ± 0.3 Gyr. This is consistent with the ages that we assign from Galactic kinematics: we find that stars with rotation period P rot < 10 days have an age of 2.0 ± 1.2 Gyr, stars with 10 days < P rot ≤ 90 days have an age of 5.6 ± 2.7 Gyr, and stars with P rot > 90 days have an age of 12.9 ± 3.5 Gyr. We find that the average age of stars with P rot < 10 days increases with decreasing stellar mass from 0.6 ± 0.3 Gyr (0.2–0.3 M ⊙) to 2.3 ± 1.3 Gyr (0.1–0.2 M ⊙).

Energetic nuclear transients in luminous and ultraluminous infrared galaxies

Energetic nuclear outbursts have been discovered in luminous and ultraluminous infrared galaxies (U/LIRGs) at unexpectedly high rates. To investigate this population of transients, we performed a search in mid-IR data from the Wide-field Infrared Survey Explorer (WISE) satellite and its NEOWISE survey to detect and characterise luminous and smoothly evolving transients in a sample of 215 U/LIRGs. We report three new transients, all with ΔL &gt; 1043 erg s−1, in addition to two previously known cases. Their host galaxies are all part of major galaxy mergers, and through radiative transfer model fitting we find that all have a significant contribution from an active galactic nucleus (AGN). We characterised the transients through measurements of their luminosities and resulting energetics, all of which are between 1050.9 erg and 1052.2 erg. The IR emission of the five transients was found to be consistent with re-radiation by the hot dust of emission at shorter wavelengths, presumably originating from an accretion event, onto the supermassive black hole. The corresponding transient rate of (1.6–4.6) × 10−3 yr−1 galaxy−1 is over an order of magnitude higher than the rate of large amplitude flares shown by AGN in the optical. We suggest that the observed transients are part of a dust-obscured population of tidal disruption events (TDEs) that have remained out of the reach of optical surveys due to the obscuring dust. In one case, this is supported by our radio observations. We also discuss other plausible explanations. The observed rate of events is significantly higher than optical TDE rates, which can be expected in U/LIRG hosts undergoing a major galaxy merger with increased stellar densities in the nuclear regions. Continued searches for such transients and their multi-wavelength follow-up is required to constrain their rate and nature.

The Epidemiology of Pediatric Autoimmune Hepatitis in Scotland: A National Cohort Study.

All prevalent pediatric patients with AIH cared for in pediatric services between January 2013 and September 2018 were included. Individual patient data were obtained from electronic patient records in the 3-main academic pediatric centers in Scotland covering the entire population. Thirty-eight patients were included (25 female) with median follow-up of 33 months (range, 2-145 mo) and 136 total patient years. The incidence between 2014 and 2017 was 0.49/100 000/y (95% confidence interval, 0.29-0.78) and point prevalence between 2013 and 2018 was 1.75/100 000 (95% confidence interval, 1.42-2.13). Thirty-five (92%) patients were autoantibody positive, most commonly anti-nuclear antibody (63%) and anti-smooth muscle antibody (42%). Thirty-seven (97%) patients had induction therapy with oral corticosteroids, 30 (79%) required maintenance treatment with azathioprine, and 23 (61%) received ursodeoxycholic acid. There were 1.4 disease flares per 10 patient years and 3 patients required liver transplantation with an overall 5-year survival rate without the need for transplantation of 95%. We calculated a novel incidence and prevalence rate for pediatric AIH in Scotland. Nearly all were invariably treated initially with corticosteroids with most placed-on azathioprine as maintenance therapy. Outcomes were generally favorable with low rates of disease flares and the need for transplantation being rare.

Medium-term impact of the SARS-CoV-2 mRNA vaccine against disease activity in patients with systemic lupus erythematosus

ObjectivesNumerous case reports have referred to new onset or flare of SLE after SARS-CoV-2 messenger RNA (mRNA) vaccines. Several observational studies showed that the short-term flare rate of SLE after...

A methodology for quantifying combustion efficiencies and species emission rates of flares subjected to crosswind

Despite strong indications that flares subjected to crosswinds can undergo fuel stripping mechanisms that reduce efficiency and lead to emission of unburned fuel, most published flare experiments have not considered the impact of a crosswind. Knowledge of flare performance in turbulent crosswinds representative of atmospheric wind is especially lacking. Accurate experiments to fill this gap can only be achieved in an environment where the wind conditions can be controlled. This work presents a methodology to determine the carbon conversion efficiency and species emission rates of a flare burning in a closed-loop wind tunnel. The developed methodology is based on solving an unsteady mass balance to relate measured accumulation rates in a closed-loop wind tunnel to emission rates, while extending the applicability and correcting errors of an earlier method. The developed methodology considers complicating factors such as infiltration and exfiltration of gases into and out of the wind tunnel, potential for reburning of products within the wind tunnel, and presence of inert species in the fuel stream. The methodology is assessed with a comprehensive Monte Carlo uncertainty and sensitivity analysis. Results suggest that carbon conversion efficiency can be measured with a systematic bias uncertainty of ≲ ±0.5%, ranging from 0.04% for a 99% efficient flare to 0.55% for a 70% efficient flare at 95% confidence, and methane emission rates can be measured within ±3.25% at 95% confidence. Demonstration experiments in a large closed-loop wind tunnel show that precision (repeatability) uncertainties will be larger but that overall (combined bias and precision) uncertainties of <10% are readily achievable.