Evolution of the UV Excess in Early-Type Galaxies

We examine the UV emission from luminous early-type galaxies as a function of redshift. We perform a stacking analysis using Galaxy Evolution Explorer (GALEX) images of galaxies in the NOAO Deep Wide Field Survey (NDWFS) Bo\"otes field and examine the evolution in the UV colors of the average galaxy. Our sample, selected to have minimal ongoing star formation based on the optical to mid-IR SEDs of the galaxies, includes 1843 galaxies spanning the redshift range $0.05\leq z\leq0.65$. We find evidence that the strength of the UV excess decreases, on average, with redshift, and our measurements also show moderate disagreement with previous models of the UV excess. Our results show little evolution in the shape of the UV continuum with redshift, consistent either with the binary model for the formation of Extreme Horizontal Branch (EHB) stars or with no evolution in EHB morphology with look-back time. However, the binary formation model predicts that the strength of the UV excess should also be relatively constant, in contradiction with our measured results. Finally, we see no significant influence of a galaxy's environment on the strength of its UV excess.Comment: 30 pages, 10 figures; accepted by ApJ. Modified from original version to reflect referee's comment

The size, density, and formation of the Orcus-Vanth system in the Kuiper belt

The Kuiper belt object Orcus and its satellite Vanth form an unusual system in the Kuiper belt. Orcus is amongst the largest objects known in the Kuiper belt, but the relative size of Vanth is much larger than that of the tiny satellites of the other large objects. From Hubble Space Telescope observations we find that Orcus and Vanth have different visible colors and that Vanth does not share the water ice absorption feature seen in the infrared spectrum of Orcus. We also find that Vanth has a nearly face-on circular orbit with a period of 9.5393 +-0.0001 days and semimajor axis of 8980+-20 km, implying a system mass of 6.32+- 0.01 X 10^20 kg or 3.8% the mass of dwarf planet Eris. From Spitzer Space Telescope observations we find that the thermal emission is consistent with a single body with diameter 940+-70 km and a geometric albedo of 0.28+-0.04. Assuming equal densities and albedos, this measurements implies sizes of Orcus and Vanth of 900 and 280 km, respectively, and a mass ratio of 33. Assuming a factor of 2 lower albedo for the non-icy Vanth, however, implies sizes of 820 and 640 km and a mass ratio of 2. The measured density depends on the assumed albedo ratio of the two objects but is approximately 1.5+-0.3 g cm^-3$, midway between typical densities measured for larger and for smaller objects. The orbit and mass ratio is consistent with formation from a giant impact and subsequent outward tidal evolution and even consistent with the system having now achieved a double synchronous state. The system can equally well be explained, however, by initial eccentric capture, Kozai cycling which increases the eccentricity and decreases the pericenter of the orbit of Vanth, and subsequent tidal evolution inward.Comment: Submitted to A

Active Galactic Nuclei and the Truncation of Star Formation in K+A Galaxies

We have searched for active galactic nuclei (AGNs) in K+A galaxies, using multiwavelength imaging and spectroscopy in the Bootes field of the NOAO Deep Wide-Field Survey. The K+A galaxies, which have had their star formation rapidly truncated, are selected via their strong Balmer absorption lines and weak H-alpha emission. Our sample consists of 24 K+A galaxies selected from 6594 0.10<z<0.35 galaxies brighter than I=20 with optical spectroscopy from the AGN and Galaxy Evolution Survey. Two thirds of the K+A galaxies are likely ongoing galaxy mergers, with nearby companion galaxies or tidal tails. Galaxy mergers may be responsible for the truncation of star formation, or we are observing the aftermath of merger triggered starbursts. As expected, the optical colors of K+A galaxies largely fall between blue galaxies with ongoing star formation and red passive galaxies. However, only 1% of the galaxies with colors between the red and blue populations are K+A galaxies, and we conclude that the truncation of star formation in K+A galaxies must have been unusually abrupt (<100 Myr). We examined the AGN content of K+A galaxies with both optical emission-line ratios (BPT diagrams) and Chandra X-ray imaging. At least half of all K+A galaxies display the optical emission-line ratios of AGNs, and a third of M_R<-22 K+A galaxies host AGNs with X-ray luminosities of 10^{42} erg/s. The faintest K+A galaxies do not show clear evidence for hosting AGNs, having emission-line ratios consistent with photoionization by massive stars and few X-ray detections. We speculate that two mechanisms may be responsible for the truncation of star formation in K+A galaxies, with AGN feedback only playing a role in M_R<-20.5 galaxies.Comment: Accepted for publication in the Astrophysical Journal. 13 pages, 8 figure

Digging supplementary buried channels: investigating the notch architecture within the CCD pixels on ESA's Gaia satellite

The European Space Agency (ESA) Gaia satellite has 106 CCD image sensors which will suffer from increased charge transfer inefficiency (CTI) as a result of radiation damage. To aid the mitigation at low signal levels, the CCD design includes Supplementary Buried Channels (SBCs, otherwise known as `notches') within each CCD column. We present the largest published sample of Gaia CCD SBC Full Well Capacity (FWC) laboratory measurements and simulations based on 13 devices. We find that Gaia CCDs manufactured post-2004 have SBCs with FWCs in the upper half of each CCD that are systematically smaller by two orders of magnitude (<50 electrons) compared to those manufactured pre-2004 (thousands of electrons). Gaia's faint star (13 < G < 20 mag) astrometric performance predictions by Prod'homme et al. and Holl et al. use pre-2004 SBC FWCs as inputs to their simulations. However, all the CCDs already integrated onto the satellite for the 2013 launch are post-2004. SBC FWC measurements are not available for one of our five post-2004 CCDs but the fact it meets Gaia's image location requirements suggests it has SBC FWCs similar to pre-2004. It is too late to measure the SBC FWCs onboard the satellite and it is not possible to theoretically predict them. Gaia's faint star astrometric performance predictions depend on knowledge of the onboard SBC FWCs but as these are currently unavailable, it is not known how representative of the whole focal plane the current predictions are. Therefore, we suggest Gaia's initial in-orbit calibrations should include measurement of the onboard SBC FWCs. We present a potential method to do this. Faint star astrometric performance predictions based on onboard SBC FWCs at the start of the mission would allow satellite operating conditions or CTI software mitigation to be further optimised to improve the scientific return of Gaia.Comment: Accepted for publication in MNRAS, 16 pages, 19 figure

Maternal plasma DHA levels increase prior to 29 days post-LH surge in women undergoing frozen embryo transfer: a prospective, observational study of human pregnancy

Context: Docosahexaenoic acid (DHA) is an important fatty acid required for neurological development but its importance during early fetal neurological organogenesis is unknown. Objective: To assess plasma fatty acid changes in early pregnancy in women undergoing natural cycle-frozen embryo transfer as a means of achieving accurately-timed periconceptual sampling. Design: Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinising hormone (LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography. Setting: Assisted Conception Unit, Glasgow Royal Infirmary, Scotland Main outcome measures: Plasma fatty acid concentrations, influence of twin pregnancies on DHA plasma concentration. Results: In pregnant women, there was a rapid, early increase in the maternal rate of change of plasma DHA concentration observed by 29 days post-LH surge (mean±SD, from 0.1±1.3 to 1.6±2.9 nmol DHA per mL plasma per day). This early pressure to increase plasma DHA concentration was further emphasised in twin pregnancies where the increase in DHA concentration over 45 days was two-fold higher than in singleton pregnancies (mean±SD increase, 74±39 nmol/mL versus 36±40 nmol/mL). An index of delta-6 desaturase activity increased 30% and positively correlated with the rate of change of DHA concentration between day 18 and 29-post LH surge (R-squared adjusted = 41%, P=0.0002). DHA was the only fatty acid with a continual accelerated increase in plasma concentration and a positive incremental area under the curve (mean±SD, 632±911 nmol/mL x day) over the first 45 days of gestation. Conclusions: An increase in maternal plasma DHA concentration is initiated in human pregnancy prior to neural tube closure which occurs at 28 days' gestation

Candida albicans colonization and dissemination from the murine gastrointestinal tract : the influence of morphology and Th17 immunity

This article is protected by copyright. All rights reserved. This work was supported by the Wellcome Trust (086558, 080088, 102705), a Wellcome Trust Strategic Award (097377) and a studentship from the University of Aberdeen. D.K. was supported by grant 5R01AI083344 from the National Institute of Allergy and Infectious Diseases and by a Voelcker Young Investigator Award from the Max and Minnie Tomerlin Voelcker Fund.Peer reviewedPublisher PD

The effect of alcohol marketing on people with, or at risk of, an alcohol problem: A rapid literature review

There is a comprehensive evidence base demonstrating the relationship between alcohol marketing and underage drinking. Far less is known about the impact of alcohol marketing on other potentially vulnerable populations, such as people with, or at risk of, an alcohol problem. For the purposes of this review, this includes people with an alcohol use disorder, in recovery from an alcohol use disorder, and hazardous and harmful drinkers. This report presents findings from a rapid review that aimed to answer the following research questions: • What is the effect of alcohol marketing on drinking behaviour in adults with, or at risk of, an alcohol problem? • What are the psychological and neurological effects of alcohol marketing in adults with, or at risk of, an alcohol problem? A rapid review of primary studies was conducted with the aim of exploring the effect or potential effect of alcohol marketing on people with, or at risk of an alcohol problem, as defined above. Studies were eligible for inclusion in this review if their populations were defined within the paper as being with, or at risk of an alcohol problem, taking into account the possibility of different definitions in different settings. Studies were only included if results or outcomes were presented separately for at least one of the populations of interest. Binge drinkers were not included as a population of interest in this review. Studies covering different aspects of the ‘marketing mix’ (the four Ps of promotion, place, product, and price) were included, with the exception of alcohol outlet density, labelling and non-branded alcohol cues. Children and adolescents were excluded from the review. Quantitative and qualitative study designs were eligible for inclusion. Outcomes related to alcohol use were included, as well as psychological indicators such as awareness of or noticing marketing, appeal or perception of alcohol advertisements, alcohol craving, intentions to consume alcohol, symptoms of alcohol dependence and alcohol-related emotions and cognitions. Searches for relevant literature were conducted through three peer-reviewed electronic literature databases (from inception to November 2021), reference list scanning and citation tracking of included studies, grey literature searching of relevant websites, and enquiries through expert networks. We undertook a narrative synthesis of included papers, grouping studies together by population (participants with harmful or hazardous consumption levels of alcohol and those recovering from an alcohol use disorder) and by type of study (quantitative; qualitative). The review included 11 studies, which focused on participants recovering from an alcohol use disorder (AUD, 6 studies) and those with hazardous or harmful consumption levels of alcohol (5 studies). Seven studies used a quantitative design and four used a qualitative design. Of the quantitative studies, three were crosssectional studies and four were experimental studies. A limited number of studies have investigated the effect of alcohol advertising in harmful/hazardous drinkers. In experimental studies, one included study found no effect of adverts on actual alcohol consumption, but found that alcohol advertising could influence positive alcohol-related emotions and cognitions among heavy drinkers. Another found that individuals who exhibit greater risky alcohol use are more likely to express intentions to consume alcohol upon exposure to beer than water ads. Finally, one study found shorter reaction times in problem drinkers relative to non-problem drinkers when exposed to non-branded alcohol images in a study where participants were instructed to respond as quickly as possible to ‘go’ stimuli whilst refraining from responding to ‘no-go’ stimuli with branded and unbranded alcohol pictures as stimuli. Two cross-sectional studies highlighted the potential risks of alcohol advertising for heavy drinkers: one found that drinkers reporting symptoms of alcohol problems were more likely to notice alcohol brands in magazines and newspapers, while another found that among students, heavy drinkers perceived alcohol adverts as more appealing; however, due to the observational designs used, neither of these studies were able to make causal inferences about the effect of alcohol advertising. Similarly, a small number of quantitative studies have investigated the effects of advertising on drinkers in recovery. Only two studies were found, both of which suggest a relatively small effect of alcohol advertising in this population. One crosssectional study reported that more than three quarters of participants (77%) recalled seeing alcohol marketing in the last six months, with 24% reporting that alcohol marketing was influential. The most influential factors affecting the purchase of a specific alcohol product included price, accessibility, the brand and alcohol percent. Using an experimental design, a further study reported increased craving after exposure to alcohol advertisements and this measure showed a positive association with the number of alcohol-dependence symptoms. In absolute terms, however, craving was relatively low. In three interview studies, respondents indicated that alcohol advertisements triggered a desire to drink, particularly those which contained the participants’ preferred drink and even where the advertisements were perceived negatively. Some reported that they viewed advertisements as being responsible for their relapse. Television was cited as being a particularly powerful medium, with feelings that television intruded into their own home. One study further reported that music and party scenes were particularly troubling in terms of creating an association with good times. Participants in both studies reported negative emotions associated with viewing alcohol advertisements, including loss, lack of belonging, anger, sadness, guilt and exclusion from the norm. Participants in these studies reported needing to use strategies to avoid alcohol advertising, either through turning off and avoiding adverts or recalling the negative aspects of alcohol use. The retail environment was also identified in one further qualitative study as being challenging for drinkers in recovery. High visibility of alcohol, especially in small shops where it is harder to avoid alcohol products, and in-store advertising were identified as risks to recovery. • Taken together, the findings of the studies included in this review suggest that an effect of alcohol marketing in people with, or at risk of, an alcohol problem is likely. • Several studies report effects of alcohol marketing such as influences on positive alcohol-related emotions and cognitions and alcohol craving, which may translate into effects on alcohol consumption. There is also evidence that alcohol marketing is perceived to act as a trigger by people in recovery from alcohol problems and pose a risk to recovery. • This review demonstrates that the impact of alcohol marketing on people with or at risk of an alcohol problem should be a concern for marketing regulators and a focus for future research. • Future research should include longitudinal and experimental studies to determine whether alcohol advertisement has a causal effect on alcohol use in people with or at risk of an alcohol problems, including the differential effects between these groups and of different types of marketing

The clinical utility of routine urinalysis in pregnancy: A prospective study

Objectives: To determine whether routine urinalysis in the antenatal period facilitates diagnosis of pre-eclampsia. Can routine urinalysis during pregnancy be discontinue in women with normal results of dipstick urinalysis and microscopy at the first antenatal visit? Design: Prospective observational study. Setting: A metropolitan public hospital and a private hospital in Sydney (NSW). Participants: One thousand women were enrolled at their first antenatal visit (March to November 1999), and 913 completed the study. Outcome measures: The primary outcome was a diagnosis of de novo hypertension (gestational hypertension, pre-eclampasia, or pre-eclampsia superimposed on chronic hypertension). Results: Thirty-five women had dipstick proteinuria at the first antenatal visit. In 25 (71%) of these women, further dipstick proteinuria was detected during pregnancy, and two (6%) were diagnosed with pre-eclampsia. Of the 867 without dipstick proteinuria at the first visit, 338 (39%) had dipstick proteinuria (> 1+) at some time during pregnancy. There were no statistically significant differences in the proportion of women with and without dipstick proteinuria at their first visit who developed hypertension during pregnancy. Only six women developed proteinuria before the onset of hypertension. Women who had an abnormal result of a midstream urine test at their first visit, compared with women with a normal result, were more likely to have a urinary tract infection diagnosed during pregnancy; however, the numbers were small. Conclusion: In the absence of hypertension, routine urinalysis during pregnancy is a poor predictor of pre-eclampsia. Therefore, after an initial screening urinalysis, routine urinalysis could be eliminated from antenatal care without adverse outcomes for women

Epidemic reproduction numbers and herd immunity

In this educational article, we explore the meanings and the applications of the reproductive numbers, namely the basic reproductive number R0, and the effective reproductive number R. We also give examples of how these numbers may be affected by the values of β, κ and D, and we go on to explore the relationship of the R0 value to the concept of herd immunity. Finally, we discuss how these concepts may contribute to the control of infectious disease outbreaks.http://www.samj.org.za/index.php/samjam2021School of Health Systems and Public Health (SHSPH