Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) have increased their stellar mass by a factor of almost 2 between z ∼ 0.9 and ...z ∼ 0.2. The numerical simulations further suggest that more than half this mass is accreted through major mergers. Using a sample of 18 distant galaxy clusters with over 600 spectroscopically confirmed cluster members between them, we search for observational evidence that major mergers do play a significant role. We find a major merger rate of 0.38 ± 0.14 mergers per Gyr at z ∼ 1. While the uncertainties, which stem from the small size of our sample, are relatively large, our rate is consistent with the results that are derived from numerical simulations. If we assume that this rate continues to the present day and that half of the mass of the companion is accreted on to the BCG during these mergers, then we find that this rate can explain the growth in the stellar mass of the BCGs that is observed and predicted by simulations. Major mergers therefore appear to be playing an important role, perhaps even the dominant one, in the build up of stellar mass in these extraordinary galaxies.
The mental health of the UK population declined at the onset of the COVID-19 pandemic. Convenience sample surveys indicate that recovery began soon after. Using a probability sample, we tracked ...mental health during the pandemic to characterise mental health trajectories and identify predictors of deterioration.
This study was a secondary analysis of five waves of the UK Household Longitudinal Study (a large, national, probability-based survey that has been collecting data continuously since January, 2009) from late April to early October, 2020 and pre-pandemic data taken from 2018-19. Mental health was assessed using the 12-item General Health Questionnaire (GHQ-12). We used latent class mixed models to identify discrete mental health trajectories and fixed-effects regression to identify predictors of change in mental health.
Mental health was assessed in 19 763 adults (≥16 years; 11 477 58·1% women and 8287 41·9% men; 3453 17·5% participants from minority ethnic groups). Mean population mental health deteriorated with the onset of the pandemic and did not begin improving until July, 2020. Latent class analysis identified five distinct mental health trajectories up to October 2020. Most individuals in the population had either consistently good (7437 39·3% participants) or consistently very good (7623 37·5% participants) mental health across the first 6 months of the pandemic. A recovering group (1727 12·0% participants) showed worsened mental health during the initial shock of the pandemic and then returned to around pre-pandemic levels of mental health by October, 2020. The two remaining groups were characterised by poor mental health throughout the observation period; for one group, (523 4·1% participants) there was an initial worsening in mental health that was sustained with highly elevated scores. The other group (1011 7·0% participants) had little initial acute deterioration in their mental health, but reported a steady and sustained decline in mental health over time. These last two groups were more likely to have pre-existing mental or physical ill-health, to live in deprived neighbourhoods, and be of Asian, Black or mixed ethnicity. Infection with SARS-CoV-2, local lockdown, and financial difficulties all predicted a subsequent deterioration in mental health.
Between April and October 2020, the mental health of most UK adults remained resilient or returned to pre-pandemic levels. Around one in nine individuals had deteriorating or consistently poor mental health. People living in areas affected by lockdown, struggling financially, with pre-existing conditions, or infection with SARS-CoV-2 might benefit most from early intervention.
None.
Objectives To examine temporal trends in sex and age specific incidence of self harm in children and adolescents, clinical management patterns, and risk of cause specific mortality following an index ...self harm episode at a young age.Design Population based cohort study.Setting UK Clinical Practice Research Datalink—electronic health records from 647 general practices, with practice level deprivation measured ecologically using the index of multiple deprivation. Patients from eligible English practices were linked to hospital episode statistics (HES) and Office for National Statistics (ONS) mortality records.Participants For the descriptive analytical phases we examined data pertaining to 16 912 patients aged 10-19 who harmed themselves during 2001-14. For analysis of cause specific mortality following self harm, 8638 patients eligible for HES and ONS linkage were matched by age, sex, and general practice with up to 20 unaffected children and adolescents (n=170 274).Main outcome measures In the first phase, temporal trends in sex and age specific annual incidence were examined. In the second phase, clinical management was assessed according to the likelihood of referral to mental health services and psychotropic drug prescribing. In the third phase, relative risks of all cause mortality, unnatural death (including suicide and accidental death), and fatal acute alcohol or drug poisoning were estimated as hazard ratios derived from stratified Cox proportional hazards models for the self harm cohort versus the matched unaffected comparison cohort.Results The annual incidence of self harm was observed to increase in girls (37.4 per 10 000) compared with boys (12.3 per 10 000), and a sharp 68% increase occurred among girls aged 13-16, from 45.9 per 10 000 in 2011 to 77.0 per 10 000 in 2014. Referrals within 12 months of the index self harm episode were 23% less likely for young patients registered at the most socially deprived practices, even though incidences were considerably higher in these localities. Children and adolescents who harmed themselves were approximately nine times more likely to die unnaturally during follow-up, with especially noticeable increases in risks of suicide (deprivation adjusted hazard ratio 17.5, 95% confidence interval 7.6 to 40.5) and fatal acute alcohol or drug poisoning (34.3, 10.2 to 115.7).Conclusions Gaining a better understanding of the mechanisms responsible for the recent apparent increase in the incidence of self harm among early-mid teenage girls, and coordinated initiatives to tackle health inequalities in the provision of services to distressed children and adolescents, represent urgent priorities for multiple public agencies.
The COVID-19 pandemic has adversely affected population mental health. We aimed to assess temporal trends in primary care-recorded common mental illness, episodes of self-harm, psychotropic ...medication prescribing, and general practitioner (GP) referrals to mental health services during the COVID-19 emergency in the UK.
We did a population-based cohort study using primary care electronic health records from general practices registered on the UK Clinical Practice Research Datalink (CPRD). We included patient records from Jan 1, 2010, to Sept 10, 2020, to establish long-term trends and patterns of seasonality, but focused primarily on the period January, 2019–September, 2020. We extracted data on clinical codes entered into patient records to estimate the incidence of depression and anxiety disorders, self-harm, prescriptions for antidepressants and benzodiazepines, and GP referrals to mental health services, and assessed event rates of all psychotropic prescriptions and self-harm. We used mean-dispersion negative binomial regression models to predict expected monthly incidence and overall event rates, which were then compared with observed rates to assess the percentage reduction in incidence and event rates after March, 2020. We also stratified analyses by sex, age group, and practice-level Index of Multiple Deprivation quintiles.
We identified 14 210 507 patients from 1697 UK general practices registered in the CPRD databases. In April, 2020, compared with expected rates, the incidence of primary care-recorded depression had reduced by 43·0% (95% CI 38·3–47·4), anxiety disorders by 47·8% (44·3–51·2), and first antidepressant prescribing by 36·4% (33·9–38·8) in English general practices. Reductions in first diagnoses of depression and anxiety disorders were largest for adults of working age (18–44 and 45–64 years) and for patients registered at practices in more deprived areas. The incidence of self-harm was 37·6% (34·8–40·3%) lower than expected in April, 2020, and the reduction was greatest for women and individuals aged younger than 45 years. By September, 2020, rates of incident depression, anxiety disorder, and self-harm were similar to expected levels. In Northern Ireland, Scotland, and Wales, rates of incident depression and anxiety disorder remained around a third lower than expected to September, 2020. In April, 2020, the rate of referral to mental health services was less than a quarter of the expected rate for the time of year (75·3% reduction 74·0–76·4).
Consequences of the considerable reductions in primary care-recorded mental illness and self-harm could include more patients subsequently presenting with greater severity of mental illness and increasing incidence of non-fatal self-harm and suicide. Addressing the effects of future lockdowns and longer-term impacts of economic instability on mental health should be prioritised.
National Institute for Health Research and Medical Research Council.
We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z ∼ 1.6, constituting the largest sample of molecular gas measurements in z > 1.5 clusters to date. The observations span three ...galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5 detections of the CO (2-1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z ∼ 1.6 cluster environments. We measure sizable gas reservoirs of 0.5-2 × 1011 M☉ in these objects, with high gas fractions (fgas) and long depletion timescales (τ), averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z = 1.6 toward enhanced gas fractions, at a level of ∼4 , but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies.
We present the first spatially resolved observations of molecular gas in a sample of cluster galaxies beyond z > 0.1. Using ALMA, we detect CO (2-1) in eight z ∼ 1.6 cluster galaxies, all within a ...single 70″ primary beam. The cluster, SpARCS-J0225, was discovered by the Spitzer Adaptation of the Red-sequence Cluster Survey, and is replete with gas-rich galaxies in close proximity, thus affording an efficient multiplexing strategy to amass the first sample of resolved CO in distant clusters. Mapping out the kinematic structure and morphology of molecular gas on ∼3.5 kpc scales reveals rotating gas disks in the majority of the galaxies, and some kinematic peculiarities, including a central gas void, a merger, and one-sided gas tails. We find that the extent of the molecular gas is slightly smaller than that of the optical HST stellar component; this is even more pronounced in low-redshift Virgo cluster galaxies. However, limited by small sample sizes of spatially resolved CO, we are unable to differentiate the distribution of stellar-to-gas radii between cluster and field environments at high redshift. Thus, at first glance, while the cluster galaxies generally look like galaxies infalling from the field, with typical main-sequence star formation rates and massive molecular gas reservoirs situated in rotating disks, they have potentially remarkable attributes, including elevated gas fractions, slightly smaller CO disks, and asymmetric gas tails. Taken in tandem, these signatures are tentative evidence for gas stripping in the z ∼ 1.6 cluster, though verification of these trends will require larger samples.
Obesity is an established risk factor for cancer in many tissues. In the mammalian intestine, a pro-obesity high-fat diet (HFD) promotes regeneration and tumorigenesis by enhancing intestinal stem ...cell (ISC) numbers, proliferation, and function. Although PPAR (peroxisome proliferator-activated receptor) nuclear receptor activity has been proposed to facilitate these effects, their exact role is unclear. Here we find that, in loss-of-function in vivo models, PPARα and PPARδ contribute to the HFD response in ISCs. Mechanistically, both PPARs do so by robustly inducing a downstream fatty acid oxidation (FAO) metabolic program. Pharmacologic and genetic disruption of CPT1A (the rate-controlling enzyme of mitochondrial FAO) blunts the HFD phenotype in ISCs. Furthermore, inhibition of CPT1A dampens the pro-tumorigenic consequences of a HFD on early tumor incidence and progression. These findings demonstrate that inhibition of a HFD-activated FAO program creates a therapeutic opportunity to counter the effects of a HFD on ISCs and intestinal tumorigenesis.
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•HFD augments intestinal stemness through PPARδ and PPARα•A PPAR-FAO program enhances stemness and tumorigenicity in a HFD•Loss or inhibition of Cpt1a-mediated FAO blunts the HFD-enhancing effects in ISCs•Early intestinal tumors arising from HFD ISCs are highly sensitive to FAO inhibition
Mana et al. demonstrate that a high-fat diet enhances intestinal stemness and tumorigenicity through a PPAR-FAO program. The PPAR family members δ and α redundantly activate a robust FAO program in stem cells where loss or inhibition of CPT1a (the mitochondrial long-chain FAO rate-controlling step) dampens these HFD effects.
Using a sample of four galaxy clusters at 1.35 < z < 1.65 and 10 galaxy clusters at 0.85 < z < 1.35, we measure the environmental quenching timescale, tQ, corresponding to the time required after a ...galaxy is accreted by a cluster for it to fully cease star formation. Cluster members are selected by a photometric-redshift criterion, and categorized as star-forming, quiescent, or intermediate according to their dust-corrected rest-frame colors and magnitudes. We employ a "delayed-then-rapid" quenching model that relates a simulated cluster mass accretion rate to the observed numbers of each type of galaxy in the cluster to constrain tQ. For galaxies of mass M* 1010.5 M , we find a quenching timescale of tQ = Gyr in the z ∼ 1.5 cluster sample, and Gyr at z ∼ 1. Using values drawn from the literature, we compare the redshift evolution of tQ to timescales predicted for different physical quenching mechanisms. We find tQ to depend on host halo mass such that quenching occurs over faster timescales in clusters relative to groups, suggesting that properties of the host halo are responsible for quenching high-mass galaxies. Between z = 0 and z = 1.5, we find that tQ evolves faster than the molecular gas depletion timescale and slower than an estimated star formation rate-outflow timescale, but is consistent with the evolution of the dynamical time. This suggests that environmental quenching in these galaxies is driven by the motion of satellites relative to the cluster environment, although due to uncertainties in the atomic gas budget at high redshift, we cannot rule out quenching due to simple gas depletion.
The COVID-19 pandemic is having profound mental health consequences for many people. Concerns have been expressed that, at their most extreme, these consequences could manifest as increased suicide ...rates. We aimed to assess the early effect of the COVID-19 pandemic on suicide rates around the world.
We sourced real-time suicide data from countries or areas within countries through a systematic internet search and recourse to our networks and the published literature. Between Sept 1 and Nov 1, 2020, we searched the official websites of these countries' ministries of health, police agencies, and government-run statistics agencies or equivalents, using the translated search terms "suicide" and "cause of death", before broadening the search in an attempt to identify data through other public sources. Data were included from a given country or area if they came from an official government source and were available at a monthly level from at least Jan 1, 2019, to July 31, 2020. Our internet searches were restricted to countries with more than 3 million residents for pragmatic reasons, but we relaxed this rule for countries identified through the literature and our networks. Areas within countries could also be included with populations of less than 3 million. We used an interrupted time-series analysis to model the trend in monthly suicides before COVID-19 (from at least Jan 1, 2019, to March 31, 2020) in each country or area within a country, comparing the expected number of suicides derived from the model with the observed number of suicides in the early months of the pandemic (from April 1 to July 31, 2020, in the primary analysis).
We sourced data from 21 countries (16 high-income and five upper-middle-income countries), including whole-country data in ten countries and data for various areas in 11 countries). Rate ratios (RRs) and 95% CIs based on the observed versus expected numbers of suicides showed no evidence of a significant increase in risk of suicide since the pandemic began in any country or area. There was statistical evidence of a decrease in suicide compared with the expected number in 12 countries or areas: New South Wales, Australia (RR 0·81 95% CI 0·72-0·91); Alberta, Canada (0·80 0·68-0·93); British Columbia, Canada (0·76 0·66-0·87); Chile (0·85 0·78-0·94); Leipzig, Germany (0·49 0·32-0·74); Japan (0·94 0·91-0·96); New Zealand (0·79 0·68-0·91); South Korea (0·94 0·92-0·97); California, USA (0·90 0·85-0·95); Illinois (Cook County), USA (0·79 0·67-0·93); Texas (four counties), USA (0·82 0·68-0·98); and Ecuador (0·74 0·67-0·82).
This is the first study to examine suicides occurring in the context of the COVID-19 pandemic in multiple countries. In high-income and upper-middle-income countries, suicide numbers have remained largely unchanged or declined in the early months of the pandemic compared with the expected levels based on the pre-pandemic period. We need to remain vigilant and be poised to respond if the situation changes as the longer-term mental health and economic effects of the pandemic unfold.
None.
Abstract
We present the results of a Spitzer/Herschel infrared photometric analysis of the largest (716) and the highest-redshift (z = 1.8) sample of brightest cluster galaxies (BCGs), those from the ...Spitzer Adaptation of the Red-Sequence Cluster Survey Given the tension that exists between model predictions and recent observations of BCGs at z < 2, we aim to uncover the dominant physical mechanism(s) guiding the stellar mass buildup of this special class of galaxies, the most massive in the Universe and uniquely residing at the centres of galaxy clusters. Through a comparison of their stacked, broad-band, infrared spectral energy distributions (SEDs) to a variety of model templates in the literature, we identify the major sources of their infrared energy output, in multiple redshift bins between 0 < z < 1.8. We derive estimates of various BCG physical parameters from the stacked νLν SEDs, from which we infer a star-forming, as opposed to a ‘red and dead’ population of galaxies, producing tens to hundreds of solar masses per year down to z = 0.5. This discovery challenges the accepted belief that BCGs should only passively evolve through a series of gas-poor, minor mergers since z ∼ 4, but agrees with an improved semi-analytic model of hierarchical structure formation that predicts star-forming BCGs throughout the epoch considered. We attribute the star formation inferred from the stacked infrared SEDs to both major and minor ‘wet’ (gas-rich) mergers, based on a lack of key signatures (to date) of cooling-flow-induced star formation, as well as a number of observational and simulation-based studies that support this scenario.
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