Modelling correlated variability in accreting black holes:the effect of high density and variable ionization on reverberation lags

We present a new release of the RELTRANS model to fit the complex cross-spectrum of accreting black holes as a function of energy. The model accounts for continuum lags and reverberation lags self-consistently in order to consider the widest possible range of X-ray variability timescales. We introduce a more self-consistent treatment of the reverberation lags, accounting for how the time variations of the illuminating flux change the ionisation level of the accretion disc. This process varies the shape of the reflection spectrum in time causing an additional source of lags besides the light crossing delay. We also consider electron densities in the accretion disc up to $10^{20}$ cm$^{-3}$, which are found in most of the stellar mass black holes and in some AGN. These high densities increase the amplitude of the reverberation lags below $1$ keV since the reflection flux enhances in the same energy range. In addition, we investigate the properties of hard lags produced by variations in the power-law index of the continuum spectrum, which can be interpreted as due to roughly $3\%$ variability in the corona's optical depth and temperature. As a test case, we simultaneously fit the lag energy spectra in a wide range of Fourier frequency for the black hole candidate MAXI J1820+070 observed with NICER. The best fit shows how the reverberation lags contribute even at the longer timescales where the hard lags are important. This proves the importance of modelling these two lags together and self-consistently in order to constrain the parameters of the system.Comment: Accepted for publication in MNRA

Primary health care for Aboriginal Australian women in remote communities after a pregnancy with hyperglycaemia

Background: Hyperglycaemia in pregnancy contributes to adverse outcomes for women and their children. The postpartum period is an opportune time to support women to reduce cardiometabolic and diabetes risk in subsequent pregnancies. Aims: To identify strengths and gaps in current care for Aboriginal women after a pregnancy complicated by hyperglycaemia. Methods: A retrospective review of the 12 month postpartum care provided by primary health centres in remote Australia in 2013-2014 identified 195 women who experienced hyperglycaemia in pregnancy (gestational diabetes (GDM) (n = 147), type 2 diabetes (T2D) (n = 39), and unclear diabetes status (n = 9)). RESULTS: Only 80 women (54%) with GDM had postpartum glycaemic checks. Of these, 32 women were diagnosed with prediabetes (n = 24) or diabetes (n = 8). Compared to women with GDM, women with T2D were more likely to have their weight measured (75% vs. 52%, p <0.01), and smoking status documented as "discussed" (65% vs. 34%, p < 0.01). Most women (97%) accessed the health centre at least once in the 12 month postpartum period but, during these visits, only 52% of women had service provision, either structured or opportunistic, related to diabetes. Conclusion: High rates of dysglycaemia among women screened for T2D after GDM in the 12 month postpartum period highlight the need for increased screening and early intervention to prevent the development of T2D and its complications. Whilst a clear strength was high postpartum attendance, many women did not attend health services for diabetes screening or management.Anna Wood, Diana MacKay, Dana Fitzsimmons, Ruth Derkenne, Renae Kirkham, Jacqueline A. Boyle, Christine Connors, Cherie Whitbread, Alison Welsh, Alex Brown, Jonathan E. Shaw, and Louise Maple-Brow

Hyperglycemia in pregnancy and developmental outcomes in children at 18-60 months of age: the PANDORA Wave 1 study

First published online: 4 April 2022This study aimed to explore the association between hyperglycemia in pregnancy (type 2 diabetes (T2D) and gestational diabetes mellitus (GDM)) and child developmental risk in Europid and Aboriginal women.PANDORA is a longitudinal birth cohort recruited from a hyperglycemia in pregnancy register, and from normoglycemic women in antenatal clinics. The Wave 1 substudy included 308 children who completed developmental and behavioral screening between age 18 and 60 months. Developmental risk was assessed using the Ages and Stages Questionnaire (ASQ) or equivalent modified ASQ for use with Aboriginal children. Emotional and behavioral risk was assessed using the Strengths and Difficulties Questionnaire. Multivariable logistic regression was used to assess the association between developmental scores and explanatory variables, including maternal T2D in pregnancy or GDM.After adjustment for ethnicity, maternal and child variables, and socioeconomic measures, maternal hyperglycemia was associated with increased developmental "concern" (defined as score ≥1 SD below mean) in the fine motor (T2D odds ratio (OR) 5.30, 95% CI 1.77-15.80; GDM OR 3.96, 95% CI 1.55-10.11) and problem-solving (T2D OR 2.71, 95% CI 1.05-6.98; GDM OR 2.54, 95% CI 1.17-5.54) domains, as well as increased "risk" (score ≥2 SD below mean) in at least one domain (T2D OR 5.33, 95% CI 1.85-15.39; GDM OR 4.86, 95% CI 1.95-12.10). Higher maternal education was associated with reduced concern in the problem-solving domain (OR 0.27, 95% CI 0.11-0.69) after adjustment for maternal hyperglycemia.Maternal hyperglycemia is associated with increased developmental concern and may be a potential target for intervention so as to optimize developmental trajectories.Angela Titmuss, Anita D, Aprano, Federica Barzi, Alex D.H. Brown, Anna Wood, Christine Connors, Jacqueline A. Boyle, Elizabeth Moore, Kerin O'Dea, Jeremy Oats, H. David McIntyre, Paul Zimmet, Jonathan E. Shaw, Maria E. Craig and Louise J. Maple-Brow

Association between hyperglycaemia in pregnancy and growth of offspring in early childhood: The PANDORA study

First published: 29 May 2022Background: Few studies have assessed whether children exposed to in utero hyperglycaemia experience different growth trajectories compared to unexposed children.Objectives:To assess association of type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) with early childhood weight, length/height and body mass index(BMI) trajectories, and with timing and magnitude of peak BMI in infancy.Methods:PANDORA is a birth cohort recruited from an Australian hyperglycaemia in pregnancy register, and women with normoglycaemia recruited from the community.Offspring growth measures were obtained from health records over a median follow-up of 3.0 years (interquartile range 1.9–4.0). This analysis included children born to Aboriginal mothers with in utero normoglycaemia (n=95), GDM (n=228) or T2D(n=131). Growth trajectories (weight, length/height and BMI) were estimated usinglinear mixed models with cubic spline functions of child age. Results:After adjustment for maternal factors (age, BMI, parity, smoking, and socio-economic measures) and child factors (age, gestational age at birth, and sex), children born to mothers with T2D or GDM had lower weight, length/height and BMI trajectories in infancy than children born to mothers with normoglycaemia, but similar weight and BMI by completion of follow-up. Children exposed to T2D had lower mean peak BMI 17.6 kg/m2(95% confidence interval [CI] 17.3–18.0) than childrenexposed to normoglycaemia (18.6 kg/m2[18.1–18.9]) (p=0.001). Conclusions: Maternal hyperglycaemia was associated with differences in early child-hood growth trajectories after adjustment for maternal BMI. Exploration of associations between in utero hyperglycaemia exposure and growth trajectories into later childhood is required.Angela Titmuss, Danielle K. Longmore, Federica Barzi, Elizabeth L. M. Barr, Vanya Webster, Anna Wood, Alison Simmonds, Alex D. H. Brown, Christine Connors, Jacqueline A. Boyle, Jeremy Oats, H. David McIntyre, Jonathan E. Shaw, Maria E. Craig, Louise J. Maple-Brown, the PANDORA Study Research Tea

Postpartum uptake of diabetes screening tests in women with gestational diabetes: The PANDORA study

OnlinePublAims To determine rates and predictors of postpartum diabetes screening among Aboriginal and/or Torres Strait Islander and non-Indigenous women with gestational diabetes mellitus (GDM). Methods PANDORA is a prospective longitudinal cohort of women recruited in pregnancy. Postpartum diabetes screening rates at 12 weeks (75-g oral glucose tolerance test (OGTT)) and 6, 12 and 18 months (OGTT, glycated haemoglobin [HbA₁Cₓ ] or fasting plasma glucose) were assessed for women with GDM (n = 712). Associations between antenatal factors and screening with any test (OGTT, HbA₁Cₓ, fasting plasma glucose) by 6 months postpartum were examined using Cox proportional hazards regression. Results Postpartum screening rates with an OGTT by 12 weeks and 6 months postpartum were lower among Aboriginal and/or Torres Strait Islander women than non-Indigenous women (18% vs. 30% at 12 weeks, and 23% vs. 37% at 6 months, p < 0.001). Aboriginal and/or Torres Strait Islander women were more likely to have completed a 6-month HbA₁Cₓ compared to non-Indigenous women (16% vs. 2%, p < 0.001). Screening by 6 months postpartum with any test was 41% for Aboriginal and/or Torres Strait Islander women and 45% for non-Indigenous women (p = 0.304). Characteristics associated with higher screening rates with any test by 6 months postpartum included, insulin use in pregnancy, first pregnancy, not smoking and lower BMI. Conclusions Given very high rates of type 2 diabetes among Aboriginal and Torres Strait Islander women, early postpartum screening with the most feasible test should be prioritised to detect prediabetes and diabetes for intervention.Anna J. Wood, I-Lynn Lee, Elizabeth L. M. Barr, Federica Barzi, Jacqueline A. Boyle, Christine Connors, Elizabeth Moore, Jeremy J. N. Oats, Harold D. McIntyre, Angela Titmuss, Alison Simmonds, Paul Z. Zimmet, Alex D. H. Brown, Sumaria Corpus, Jonathan E. Shaw, Louise J. Maple-Brown, on behalf of PANDORA Study tea

Association between maternal hyperglycemia in pregnancy and offspring anthropometry in early childhood: the pandora wave 1 study

Background: In-utero hyperglycemia exposure influences later cardiometabolic risk, although few studies include women with pre-existing type 2 diabetes (T2D) or assess maternal body mass index (BMI) as a potential confounder. Objective: To explore the association of maternal T2D and gestational diabetes mellitus (GDM) with childhood anthropometry, and the influence of maternal BMI on these associations. Methods: The PANDORA cohort comprises women (n = 1138) and children (n = 1163). Women with GDM and T2D were recruited from a hyperglycemia in pregnancy register, and women with normoglycemia from the community. Wave 1 follow-up included 423 children, aged 1.5–5 years (median follow-up age 2.5 years). Multivariable linear regression assessed associations between maternal antenatal variables, including BMI and glycemic status, with offspring anthropometry (weight, height, BMI, skinfold thicknesses, waist, arm and head circumferences). Results: Greater maternal antenatal BMI was associated with increased anthropometric measures in offspring independent of maternal glycemic status. After adjustment, including for maternal BMI, children exposed to maternal GDM had lower mean weight (−0.54 kg, 95% CI: −0.99, −0.11), BMI (−0.55 kg/m2, 95% CI: −0.91, −0.20), head (−0.52 cm, 95% CI: −0.88, −0.16) and mid-upper arm (−0.32 cm, 95% CI: −0.63, −0.01) circumferences, and greater mean suprailiac skinfold (0.78 mm, 95% CI: 0.13, 1.43), compared to children exposed to normoglycemia. Adjustment for maternal BMI strengthened the negative association between GDM and child weight, BMI and circumferences. Children exposed to maternal T2D had smaller mean head circumference (−0.82 cm, 95% CI: −1.33, −0.31) than children exposed to normoglycemia. Maternal T2D was no longer associated with greater child mean skinfolds (p = 0.14) or waist circumference (p = 0.18) after adjustment for maternal BMI. Conclusions: Children exposed to GDM had greater suprailiac skinfold thickness than unexposed children, despite having lower mean weight, BMI and mid-upper arm circumference, and both GDM and T2D were associated with smaller mean head circumference. Future research should assess whether childhood anthropometric differences influence lifetime cardiometabolic and neurodevelopmental risk.Angela Titmuss, Federica Barzi, Elizabeth L. M. Barr, Vanya Webster, Anna Wood, Joanna Kelaart, Marie Kirkwood, Christine Connors, Jacqueline A. Boyle, Elizabeth Moore, Jeremy Oats, H. David McIntyre, Paul Zimmet, Alex D. H. Brown, Jonathan E. Shaw, Maria E. Craig, and Louise J. Maple-Brow

New games, new rules: big data and the changing context of strategy

Big data and the mechanisms by which it is produced and disseminated introduce important changes in the ways information is generated and made relevant for organizations. Big data often represents miscellaneous records of the whereabouts of large and shifting online crowds. It is frequently agnostic, in the sense of being produced for generic purposes or purposes different from those sought by big data crunching. It is based on varying formats and modes of communication (e.g., texts, image and sound), raising severe problems of semiotic translation and meaning compatibility. Crucially, the usefulness of big data rests on their steady updatability, a condition that reduces the time span within which this data is useful or relevant. Jointly, these attributes challenge established rules of strategy making as these are manifested in the canons of procuring structured information of lasting value that addresses specific and long-term organizational objectives. The developments underlying big data thus seem to carry important implications for strategy making, and the data and information practices with which strategy has been associated. We conclude by placing the understanding of these changes within the wider social and institutional context of longstanding data practices and the significance they carry for management and organizations