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ObjectiveExercise plays a crucial role in maintaining and improving human health. However, the precise molecular mechanisms that govern the body's response to exercise or/compared to periods of inactivity remain elusive. Current evidence appears to suggest that exercise exerts a seemingly dual influence on macrophage polarization states, inducing both pro-immune response M1 activation and cell-repair-focused M2 activation. To reconcile this apparent paradox, we leveraged a comprehensive meta-analysis of 75 diverse exercise and immobilization published datasets (7000+ samples), encompassing various exercise modalities, sampling techniques, and species.Methods75 exercise and immobilization expression datasets were identified and processed for analysis. The data was analyzed using boolean relationships which uses binary gene expression relationships in order to increase the signal to noise achieved from the data, allowing for the use of comparison across such a diverse set of datasets. We utilized a boolean relationship-aided macrophage gene model [1], to model the macrophage polarization state in pre and post exercise samples in both immediate exercise and long term training.ResultsOur modeling uncovered a key temporal dynamic: exercise triggers an immediate M1 surge, while long term training transitions to sustained M2 activation. These patterns were consistent across different species (human vs mouse), sampling methods (blood vs muscle biopsy), and exercise type (resistance vs endurance), and routinely showed statistically significant results. Immobilization was shown to have the opposite effect of exercise by triggering an immediate M2 activation. Individual characteristics like gender, exercise intensity and age were found to impact the degree of polarization without changing the overall patterns. To model macrophages within the specific context of muscle tissue, we identified a focused gene set signature of muscle resident macrophage polarization, allowing for the precise measurement of macrophage activity in response to exercise within the muscle.ConclusionsThese consistent patterns across all 75 examined studies suggest that the long term health benefits of exercise stem from its ability to orchestrate a balanced and temporally-regulated interplay between pro-immune response (M1) and reparative macrophage activity (M2). Similarly, it suggests that an imbalance between pro-immune and cell repair responses could facilitate disease development. Our findings shed light on the intricate molecular choreography behind exercise-induced health benefits with a particular insight on its effect on the macrophages within the muscle.

OBJECTIVES: We conducted an implementation science mental health treatment study in western Kenya, testing strategies for scale up of evidence-based mental health services for common adult disorders using a non-specialist workforce, integrated with existing primary care (Sequential Multiple, Assignment Randomized Trial of non-specialist-delivered psychotherapy (Interpersonal Psychotherapy) and/or medication (fluoxetine) for major depression and post-traumatic stress disorder (PTSD) (SMART DAPPER)). Because study launch coincided with the COVID-19 pandemic, participants were allowed to attend treatment visits via mHealth (audio-only mobile phone) or in-person. We conducted a secondary data analysis of the parent study to evaluate preference for mHealth or in-person treatment among our study participants, including rationale for choosing in-person or mHealth treatment modality, and comparison of baseline demographic and clinical characteristics. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: Participants were public sector primary care patients at Kisumu County Hospital in western Kenya with major depression and/or PTSD and were individually randomised to non-specialist delivery of evidence-based psychotherapy or medication (n=2162). OUTCOMES: Treatment modality preference and rationale were ascertained before randomised assignment to treatment arm (psychotherapy or medication). The parent SMART DAPPER study baseline assessment included core demographic (age, gender, relationship status, income, clinic transport time and cost) and clinical data (eg, depression and PTSD symptoms, trauma exposures, medical comorbidities and history of mental healthcare). Given that this evaluation of mHealth treatment preference sought to identify the demographic and clinical characteristics of participants who chose in-person or mHealth treatment modality, we included most SMART DAPPER core measurement domains (not all subcategories). RESULTS: 649 (30.3%) SMART DAPPER participants preferred treatment via mHealth, rather than in person. The most cited rationales for choosing mHealth were affordability (18.5%) (eg, no transportation cost) and convenience (12.9%). On multivariate analysis, compared with those who preferred in-person treatment, participants who chose mHealth were younger and had higher constraints on receiving in-person treatment, including transport time 1.004 (1.00, 1.007) and finances 0.757 (0.612, 0.936). Higher PTSD symptoms 0.527 (0.395, 0.702) and higher disability 0.741 (0.559, 0.982) were associated with preference for in-person treatment. CONCLUSIONS: To our knowledge, this is the first study of public sector mental healthcare delivered by non-specialists via mHealth for major depression and/or PTSD in Sub-Saharan Africa. Our finding that mHealth treatment is preferred by approximately one-third of participants, particularly younger individuals with barriers to in-person care, may inform future mHealth research to (1) address knowledge gaps in mental health service implementation and (2) improve mental healthcare access to evidence-based treatment. TRIAL REGISTRATION NUMBER: NCT03466346.

BACKGROUND: Racial/ethnic and socioeconomic disparities in diabetes and hypertension outcomes persist in the United States (U.S.), and worsened during the COVID-19 pandemic. This was in part due to suboptimal implementation of telehealth in U.S. safety-net settings alongside the pre-existing digital divide - structural determinants that limit access to digital tools by marginalized communities. To improve health equity, it is critical that health systems in the U.S. integrate principles of digital and health literacy for more equitable chronic disease care. METHODS: We are conducting a 2x2 factorial randomized controlled trial, in partnership with a Community Advisory Board, assessing a multi-level intervention addressing barriers that affect the equitable use of telehealth amongst low-income patients in San Francisco County. Patient-level support is provided through the evidence-based strategies of health coaching and digital navigation (digital coaching); clinic-level support includes equity dashboards, patient advisory councils, and practice facilitation. We are randomizing 600 low-income, racially/ethnically diverse English and Spanish-speaking patients with uncontrolled diabetes to receive digital coaching (n=200) vs. usual care (n=400) for 3 months; and 11 public health primary care clinics to clinic support vs. usual care for 24 months. We aim to evaluate the impact of patient and clinic level interventions to determine individual effectiveness and potential synergistic impact on clinical and process measures related to diabetes and telehealth outcomes. RESULTS: The studys primary clinical outcome is change in patient-level Hemoglobin A1C (A1c); the primary process outcome is patient portal usage. Secondary clinical outcomes include changes in patient-level systolic blood pressure (SBP) and microalbuminuria (UACR), and changes in clinic-level A1c, SBP, and UACR. Secondary process outcomes assess patient-level changes in digital literacy, medication adherence, patient activation, and visit show rates, and clinic-level measures of telehealth adoption. DISCUSSION: The ACCTiVATE trial tests a multi-level intervention developed through a stakeholder-engaged research approach and user-centered design to be feasible and acceptable for impacted communities. If efficacious, ACCTiVATE may provide a scalable model to improve chronic health outcomes and telehealth equity among marginalized racial/ethnic populations experiencing structural and interpersonal access barriers. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT06598436. Registered 15 September 2024.

We report a 40-year history of SF6 atmospheric mole fractions measured at the Advanced Global Atmospheric Gases Experiment (AGAGE) monitoring sites, combined with archived air samples, to determine emission estimates from 1978 to 2018. Previously we reported a global emission rate of 7.3±0.6 Gg yr−1 in 2008 and over the past decade emissions have continued to increase by about 24 % to 9.04±0.35 Gg yr−1 in 2018. We show that changing patterns in SF6 consumption from developed (Kyoto Protocol Annex-1) to developing countries (non-Annex-1) and the rapid global expansion of the electric power industry, mainly in Asia, have increased the demand for SF6-insulated switchgear, circuit breakers, and transformers. The large bank of SF6 sequestered in this electrical equipment provides a substantial source of emissions from maintenance, replacement, and continuous leakage. Other emissive sources of SF6 occur from the magnesium, aluminium, and electronics industries as well as more minor industrial applications. More recently, reported emissions, including those from electrical equipment and metal industries, primarily in the Annex-1 countries, have declined steadily through substitution of alternative blanketing gases and technological improvements in less emissive equipment and more efficient industrial practices. Nevertheless, there are still demands for SF6 in Annex-1 countries due to economic growth, as well as continuing emissions from older equipment and additional emissions from newly installed SF6-insulated electrical equipment, although at low emission rates. In addition, in the non-Annex-1 countries, SF6 emissions have increased due to an expansion in the growth of the electrical power, metal, and electronics industries to support their continuing development. There is an annual difference of 2.5–5 Gg yr−1 (1990–2018) between our modelled top-down emissions and the UNFCCC-reported bottom-up emissions (United Nations Framework Convention on Climate Change), which we attempt to reconcile through analysis of the potential contribution of emissions from the various industrial applications which use SF6. We also investigate regional emissions in East Asia (China, S. Korea) and western Europe and their respective contributions to the global atmospheric SF6 inventory. On an average annual basis, our estimated emissions from the whole of China are approximately 10 times greater than emissions from western Europe. In 2018, our modelled Chinese and western European emissions accounted for ∼36 % and 3.1 %, respectively, of our global SF6 emissions estimate.

BackgroundTobacco smoke may affect atopic dermatitis (AD) because of its known effects on humoral and cellular immunity, but prior studies lack data on disease severity and biomarkers over time.ObjectiveWe investigated the association between passive and active tobacco smoke exposure (TSE) during childhood and adolescence and the activity and severity of AD.MethodsA birth cohort of 10,521 individuals was followed through adolescence as part of the Avon Longitudinal Study of Parents and Children. We used mixed-effect models to determine the risk of AD (based on repeated assessments) with passive smoke exposure during childhood, active TSE during adolescence, and using a serum biomarker of tobacco exposure (cotinine) at 3 time points.ResultsAfter adjusting for confounding factors, there was no evidence of a relationship between passive TSE and concurrent AD activity in childhood (adjusted odds ratio, 0.95; 95% confidence interval, 0.83, 1.07) or of an increased risk between active smoking and AD activity in adolescence (adjusted odds ratio, 0.57; 95% confidence interval, 0.44, 0.75). Secondary analyses demonstrated no dose-response relationship and no increased severity of AD with passive or active TSE. Furthermore, we found no increased risk of AD with a cumulative measure of passive TSE across childhood (adjusted relative risk ratio, 0.98; 95% confidence interval, 0.96, 1.00).ConclusionNeither active nor passive TSE was associated with AD during childhood and adolescence.

The educational historian Brian Simon is well known for his portrayal of the social and political conflicts surrounding adult working-class education in 19th and early 20th-century England. However, the third and fourth volumes of his classic history of education in Britain, covering the period from 1920 to 1940 and 1940 to 1990 respectively, include very little about adult education. These later volumes, indeed, focus on the development of schooling in these years. Yet during his writing of the fourth volume, begun in the late 1970s and published in 1991, the work of the Italian Marxist Antonio Gramsci was published in English and became widely supported among British Marxists. Simon himself was attracted to Gramsci's ideas because of the possibilities that they seemed to raise for educational and social change, in contrast with the neo-Marxist theories of others such as Michael Young and Pierre Bourdieu. This paper traces the development of Simon's approach to adult education, and offers an explanation for his failure to develop a more fully Gramscian version of the history of adult education.

We reconstruct atmospheric abundances of the potent greenhouse gas c-C4F8 (perfluorocyclobutane, perfluorocarbon PFC-318) from measurements of in situ, archived, firn, and aircraft air samples with precisions of ∼1 %–2 % reported on the SIO-14 gravimetric calibration scale. Combined with inverse methods, we found near-zero atmospheric abundances from the early 1900s to the early 1960s, after which they rose sharply, reaching 1.66 ppt (parts per trillion dry-air mole fraction) in 2017. Global c-C4F8 emissions rose from near zero in the 1960s to 1.2±0.1 (1σ) Gg yr−1 in the late 1970s to late 1980s, then declined to 0.77±0.03 Gg yr−1 in the mid-1990s to early 2000s, followed by a rise since the early 2000s to 2.20±0.05 Gg yr−1 in 2017. These emissions are significantly larger than inventory-based emission estimates. Estimated emissions from eastern Asia rose from 0.36 Gg yr−1 in 2010 to 0.73 Gg yr−1 in 2016 and 2017, 31 % of global emissions, mostly from eastern China. We estimate emissions of 0.14 Gg yr−1 from northern and central India in 2016 and find evidence for significant emissions from Russia. In contrast, recent emissions from northwestern Europe and Australia are estimated to be small (≤1 % each). We suggest that emissions from China, India, and Russia are likely related to production of polytetrafluoroethylene (PTFE, “Teflon”) and other fluoropolymers and fluorochemicals that are based on the pyrolysis of hydrochlorofluorocarbon HCFC-22 (CHClF2) in which c-C4F8 is a known by-product. The semiconductor sector, where c-C4F8 is used, is estimated to be a small source, at least in South Korea, Japan, Taiwan, and Europe. Without an obvious correlation with population density, incineration of waste-containing fluoropolymers is probably a minor source, and we find no evidence of emissions from electrolytic production of aluminum in Australia. While many possible emissive uses of c-C4F8 are known and though we cannot categorically exclude unknown sources, the start of significant emissions may well be related to the advent of commercial PTFE production in 1947. Process controls or abatement to reduce the c-C4F8 by-product were probably not in place in the early decades, explaining the increase in emissions in the 1960s and 1970s. With the advent of by-product reporting requirements to the United Nations Framework Convention on Climate Change (UNFCCC) in the 1990s, concern about climate change and product stewardship, abatement, and perhaps the collection of c-C4F8 by-product for use in the semiconductor industry where it can be easily abated, it is conceivable that emissions in developed countries were stabilized and then reduced, explaining the observed emission reduction in the 1980s and 1990s. Concurrently, production of PTFE in China began to increase rapidly. Without emission reduction requirements, it is plausible that global emissions today are dominated by China and other developing countries. We predict that c-C4F8 emissions will continue to rise and that c-C4F8 will become the second most important emitted PFC in terms of CO2-equivalent emissions within a year or two. The 2017 radiative forcing of c-C4F8 (0.52 mW m−2) is small but emissions of c-C4F8 and other PFCs, due to their very long atmospheric lifetimes, essentially permanently alter Earth's radiative budget and should be reduced. Significant emissions inferred outside of the investigated regions clearly show that observational capabilities and reporting requirements need to be improved to understand global and country-scale emissions of PFCs and other synthetic greenhouse gases and ozone-depleting substances.

BACKGROUND: The COVID-19 pandemic led to dramatic changes in the lives of children that impact cardiometabolic health. Cities and counties had varying policies with respect to school closure, recreational programs, and efforts to mitigate food insecurity and economic distress. Our objective was to evaluate changes in BMI-z score and prevalence of overweight/obesity prior to and during the pandemic among children in San Francisco, CA, where public schools were closed for 18-months. METHODS: This was an electronic medical record-based retrospective cohort study. We included 15,401 children, 4-17 years of age at study onset. Our exposure was time into each of three time periods: (1) March 2018-February 2019; (2) March 2019-February 2020; (3) March 2020-August 2021 (the pandemic period of school closure). Generalized estimating equations (GEE) were used to assess changes in BMI-z score and overweight/obesity across the three time periods. We assessed for effect modification by age-category, insurance status, and race/ethnicity. RESULTS: Mean BMI-z score increased by 0.06 per year in time period 2, the year prior to the pandemic (p

BACKGROUND: Promoting physical activity among young individuals with cardiovascular disease (CVD) risk factors such as hypertension, diabetes, or chronic kidney disease can lower systolic blood pressure (BP). We sought to determine whether a 6-month intervention using a physical activity tracker was feasible and effective, compared with usual care. METHODS: Participants were recruited at a single academic medical center. Those aged 8-30 years were randomized in a 2:1 ratio to either the intervention (use of a Fitbit physical activity tracker coupled with feedback regarding the participants step count) or usual care. The primary feasibility outcomes were screening-to-enrollment ratio and 6-month retention rates; the primary clinical outcome was a change in systolic BP from 0-6 months. RESULTS: Sixty-three participants were enrolled (57% male; mean age: 18 ± 4 years). The screening-to-enrollment ratio was 1.8:1. Six-month retention was 62% in the intervention group and 86% in the control group (p = 0.08). Mean change in systolic BP in the intervention group was not significantly different from the control group at 6 months (- 2.3 mmHg; 95% CI - 6.5, 1.8 vs. 3.0 mmHg; 95% CI - 2.5, 8.4, respectively, p = 0.12). CONCLUSIONS: Among children and young adults at elevated CVD risk, the use of a physical activity tracker coupled with tailored feedback regarding their step count progress was feasible but not sustained over time. Physical activity tracker use did not have a statistically significant effect on BP after 6 months. Augmented strategies to mitigate risk in young patients at high risk for early-onset CVD should be explored. This trial is registered at ClinicalTrials.gov (NCT03325426).

High frequency measurements of trifluoromethane (HFC-23, CHF3), a potent hydrofluorocarbon greenhouse gas, largely emitted to the atmosphere as a by-product of the production of the hydrochlorofluorocarbon HCFC-22 (CHClF2), at five core stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, combined with measurements on firn air, old Northern Hemisphere air samples and Cape Grim Air Archive (CGAA) air samples, are used to explore the current and historic changes in the atmospheric abundance of HFC-23. These measurements are used in combination with the AGAGE 2-D atmospheric 12-box model and a Bayesian inversion methodology to determine model atmospheric mole fractions and the history of global HFC-23 emissions. The global modelled annual mole fraction of HFC-23 in the background atmosphere was 28.9 ± 0.6 pmol mol−1 at the end of 2016, representing a 28 % increase from 22.6 ± 0.4 pmol mol−1 in 2009. Over the same time frame, the modelled mole fraction of HCFC-22 increased by 19 % from 199 ± 2 to 237 ± 2 pmol mol−1. However, unlike HFC-23, the annual average HCFC-22 growth rate slowed from 2009 to 2016 at an annual average rate of −0.5 pmol mol−1 yr−2. This slowing atmospheric growth is consistent with HCFC-22 moving from dispersive (high fractional emissions) to feedstock (low fractional emissions) uses, with HFC-23 emissions remaining as a consequence of incomplete mitigation from all HCFC-22 production.Our results demonstrate that, following a minimum in HFC-23 global emissions in 2009 of 9.6 ± 0.6, emissions increased to a maximum in 2014 of 14.5 ± 0.6 Gg yr−1 and then declined to 12.7 ± 0.6 Gg yr−1 (157 Mt CO2 eq. yr−1) in 2016. The 2009 emissions minimum is consistent with estimates based on national reports and is likely a response to the implementation of the Clean Development Mechanism (CDM) to mitigate HFC-23 emissions by incineration in developing (non-Annex 1) countries under the Kyoto Protocol. Our derived cumulative emissions of HFC-23 during 2010–2016 were 89 ± 2 Gg (1.1 ± 0.2 Gt CO2 eq.), which led to an increase in radiative forcing of 1.0 ± 0.1 mW m−2 over the same period. Although the CDM had reduced global HFC-23 emissions, it cannot now offset the higher emissions from increasing HCFC-22 production in non-Annex 1 countries, as the CDM was closed to new entrants in 2009. We also find that the cumulative European HFC-23 emissions from 2010 to 2016 were ∼ 1.3 Gg, corresponding to just 1.5 % of cumulative global HFC-23 emissions over this same period. The majority of the increase in global HFC-23 emissions since 2010 is attributed to a delay in the adoption of mitigation technologies, predominantly in China and East Asia. However, a reduction in emissions is anticipated, when the Kigali 2016 amendment to the Montreal Protocol, requiring HCFC and HFC production facilities to introduce destruction of HFC-23, is fully implemented.

Introduction: The current study aimed to expand current knowledge on cat-related guilt beyond work cat conflict and guilt about cat parenting to determine the influence of owner’s personality traits, choices regarding their cat’s lifestyle, and cat-related guilt factors. Additionally, we sought to assess potential predictors of anxiety and depression to determine the contributions of cat-related guilt, owner personality traits, and social compensatory behaviors, while controlling for owner demographics. Methods: An online, anonymous, cross-sectional survey was disseminated between October 18 and 28, 2023. Survey respondents (n = 531) were adults who resided in the United States and were the primary caretakers of a cat they had owned for at least 6 months. Descriptive statistics captured cat owner demographics. Multiple linear regression was used to predict guilt about cat parenting, work cat conflict, anxiety, and depression. Results: Significant predictors of guilt about cat parenting included guilt factors, time away, indoor, and attention. Significant predictors of work cat conflict included gender and cat guilt factors, time away, and attention. Work cat conflict and personality traits (extraversion, agreeableness, conscientiousness, and neuroticism) significantly predicted depression scores. Lastly, anxiety scores were significantly predicted by work cat conflict, neuroticism, and social compensatory behaviors. Discussion: Findings from this study extend understanding of cat owner’s guilt and illuminate how their personality traits, compensatory behaviors, and lifestyle choices for their pets influence how they perceive and internalize feelings about their cat parenting practices. The nuanced nature of parenting guilt receives limited social recognition, leaving owners isolated in their disenfranchised guilt which significantly influences feelings of anxiety and depression. Our findings underscore the imperative for research and public education about beneficial ways to integrate social contact and enrichment activities to foster both human and animal wellbeing.

Exercise-induced muscle adaptations vary based on exercise modality and intensity. We constructed a signalling network model from 87 published studies of human or rodent skeletal muscle cell responses to endurance or resistance exercise in vivo or simulated exercise in vitro. The network comprises 259 signalling interactions between 120 nodes, representing eight membrane receptors and eight canonical signalling pathways regulating 14 transcriptional regulators, 28 target genes and 12 exercise-induced phenotypes. Using this network, we formulated a logic-based ordinary differential equation model predicting time-dependent molecular and phenotypic alterations following acute endurance and resistance exercises. Compared with nine independent studies, the model accurately predicted 18/21 (85%) acute responses to resistance exercise and 12/16 (75%) acute responses to endurance exercise. Detailed sensitivity analysis of differential phenotypic responses to resistance and endurance training showed that, in the model, exercise regulates cell growth and protein synthesis primarily by signalling via mechanistic target of rapamycin, which is activated by Akt and inhibited in endurance exercise by AMP-activated protein kinase. Endurance exercise preferentially activates inflammation via reactive oxygen species and nuclear factor κB signalling. Furthermore, the expected preferential activation of mitochondrial biogenesis by endurance exercise was counterbalanced in the model by protein kinase C in response to resistance training. This model provides a new tool for investigating cross-talk between skeletal muscle signalling pathways activated by endurance and resistance exercise, and the mechanisms of interactions such as the interference effects of endurance training on resistance exercise outcomes.

ObjectiveTo determine if baseline diabetic retinopathy (DR) severity mediates the relationship between health insurance status and DR progression.DesignRetrospective cohort study.SubjectsSeven hundred sixteen patients aged ≥ 18 years with a diagnosis of type 1 or 2 diabetes mellitus, and a diagnosis of nonproliferative DR (NPDR) were identified from the electronic health record of a tertiary academic center between June 2012 and February 2022.MethodsNPDR severity at baseline was the proposed mediator in the relationship between insurance status and proliferative DR (PDR) progression. Logistic regression was used to determine the association between insurance status and NPDR severity at baseline, and Cox proportional hazards regression was used to assess the association between insurance status and time to PDR progression. To analyze the mediation effect of NPDR severity at baseline, a counterfactual approach, which decomposes a total effect into a natural direct effect and a natural indirect effect was applied.Main outcome measuresTime to progression from first NPDR diagnosis to first PDR diagnosis.ResultsOf the 716 patients, 581 (81%) had Medicare or private insurance, 107 (15%) had Medicaid, and 28 (4.0%) were uninsured at their baseline eye visit. Uninsured or Medicaid patients had a higher proportion of moderate or severe NPDR at their baseline eye visit and a higher proportion of progression to PDR. After adjusting for confounders and NPDR severity at baseline, patients who were uninsured had significantly greater risk of progression to PDR compared with that of patients with Medicare/private insurance (hazard ratio [HR]: 2.63; 95% confidence interval [CI]: 1.10-6.25). Patients with Medicaid also had an increased risk of progression to PDR compared with that of patients with Medicare/private insurance, although not statistically significant (HR: 1.53; 95% CI: 0.81-2.89). NPDR severity at baseline mediated 41% of the effect of insurance status (uninsured vs. Medicare/private insurance) on PDR progression.ConclusionsPatients who were uninsured were more likely to have an advanced stage of NPDR at their baseline eye visit and were at significantly greater risk of progression to PDR compared with patients who had Medicare or were privately insured. Mediation analysis revealed that differences in baseline NPDR severity by insurance explained a significant proportion of the relationship between insurance status and DR progression.Financial disclosuresProprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

This article contributes to the growing evidence based on well-being in doctoral study. It draws on 35 qualitative, in-depth interviews to explore how the well-being of an understudied group--working doctoral student mothers--is affected when undertaking part-time PhDs. While there is a growing literature on the research student experience and an increased awareness of mental health issues in doctoral study, there has been little exploration of the experiences of part-time PhD students. Moreover, this is particularly true of mothers undertaking doctorates on a part-time basis. The experiences of this sub-group of research students constitute the gap to which this paper responds. It explores the consequences of having to straddle a number of competing domains and examines how the gender role conflict, marginalisation and lack of support experienced by doctoral student mothers impact their psychological, physical and social well-being. The article concludes with a number of recommendations that institutions may wish to consider.

Based on observations of the chlorofluorocarbons CFC-13 (chlorotrifluoromethane), ΣCFC-114 (combined measurement of both isomers of dichlorotetrafluoroethane), and CFC-115 (chloropentafluoroethane) in atmospheric and firn samples, we reconstruct records of their tropospheric histories spanning nearly 8 decades. These compounds were measured in polar firn air samples, in ambient air archived in canisters, and in situ at the AGAGE (Advanced Global Atmospheric Gases Experiment) network and affiliated sites. Global emissions to the atmosphere are derived from these observations using an inversion based on a 12-box atmospheric transport model. For CFC-13, we provide the first comprehensive global analysis. This compound increased monotonically from its first appearance in the atmosphere in the late 1950s to a mean global abundance of 3.18 ppt (dry-air mole fraction in parts per trillion, pmol mol−1) in 2016. Its growth rate has decreased since the mid-1980s but has remained at a surprisingly high mean level of 0.02 ppt yr−1 since 2000, resulting in a continuing growth of CFC-13 in the atmosphere. ΣCFC-114 increased from its appearance in the 1950s to a maximum of 16.6 ppt in the early 2000s and has since slightly declined to 16.3 ppt in 2016. CFC-115 increased monotonically from its first appearance in the 1960s and reached a global mean mole fraction of 8.49 ppt in 2016. Growth rates of all three compounds over the past years are significantly larger than would be expected from zero emissions. Under the assumption of unchanging lifetimes and atmospheric transport patterns, we derive global emissions from our measurements, which have remained unexpectedly high in recent years: mean yearly emissions for the last decade (2007–2016) of CFC-13 are at 0.48 ± 0.15 kt yr−1 (> 15 % of past peak emissions), of ΣCFC-114 at 1.90 ± 0.84 kt yr−1 (∼ 10 % of peak emissions), and of CFC-115 at 0.80 ± 0.50 kt yr−1 (> 5 % of peak emissions). Mean yearly emissions of CFC-115 for 2015–2016 are 1.14 ± 0.50 kt yr−1 and have doubled compared to the 2007–2010 minimum. We find CFC-13 emissions from aluminum smelters but if extrapolated to global emissions, they cannot account for the lingering global emissions determined from the atmospheric observations. We find impurities of CFC-115 in the refrigerant HFC-125 (CHF2CF3) but if extrapolated to global emissions, they can neither account for the lingering global CFC-115 emissions determined from the atmospheric observations nor for their recent increases. We also conduct regional inversions for the years 2012–2016 for the northeastern Asian area using observations from the Korean AGAGE site at Gosan and find significant emissions for ΣCFC-114 and CFC-115, suggesting that a large fraction of their global emissions currently occur in northeastern Asia and more specifically on the Chinese mainland.

High-frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements, HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3) and HFC-32 (CH2F2), have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. Global mean mole fractions of HCFC-22, -141b, and -142b have increased throughout the observation period, reaching 234, 24.3 and 22.4 pmol mol−1, respectively, in 2015. HCFC-124 reached a maximum global mean mole fraction of 1.48 pmol mol−1 in 2007 and has since declined by 23 % to 1.14 pmol mol−1 in 2015. The HFCs all show increasing global mean mole fractions. In 2015 the global mean mole fractions (pmol mol−1) were 83.3 (HFC-134a), 18.4 (HFC-125), 17.7 (HFC-143a) and 10.5 (HFC-32). The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of emissive uses of HCFCs with global production and consumption capped in 2013 to mitigate their environmental impact as both ozone-depleting substances and important greenhouse gases. We find that this change has coincided with a stabilisation, or moderate reduction, in global emissions of the four HCFCs with aggregated global emissions in 2015 of 449 ± 75 Gg yr−1, in CO2 equivalent units (CO2 eq.) 0.76 ± 0.1 Gt yr−1, compared with 483 ± 70 Gg yr−1 (0.82 ± 0.1 Gt yr−1 CO2 eq.) in 2010 (uncertainties are 1σ throughout this paper). About 79 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global emissions appear to have been relatively similar since 2011, in spite of the 2013 cap on emissive uses. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing mole fraction growth rates with aggregated global HFC emissions of 327 ± 70 Gg yr−1 (0.65 ± 0.12 Gt yr−1 CO2 eq.) in 2015 compared to 240 ± 50 Gg yr−1 (0.47 ± 0.08 Gt yr−1 CO2 eq.) in 2010. We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly averaged over the 5-year period 2011–2015, compared to 2006–2010. As noted by Lunt et al. (2015) this may reflect a change to refrigerant blends, such as R-410A, which contain HFC-32 and -125 as a 50 : 50 blend.