A search for p-modes and other variability in the binary system 85 Pegasi using MOST photometry

Context: Asteroseismology has great potential for the study of metal-poor stars due to its sensitivity to determine stellar ages. Aims: Our goal was to detect p-mode oscillations in the metal-poor sub-dwarf 85 Peg A and to search for other variability on longer timescales. Methods: We have obtained continuous high-precision photometry of the binary system 85 Pegasi with the MOST space telescope in two seasons (2005 & 2007). Furthermore, we redetermined vsini for 85 Peg A using high resolution spectra obtained through the ESO archive, and used photometric spot modeling to interpret long periodic variations. Results: Our frequency analysis yields no convincing evidence for p-modes significantly above a noise level of 4 ppm. Using simulated p-mode patterns we provide upper RMS amplitude limits for 85 Peg A. The light curve shows evidence for variability with a period of about 11 d and this periodicity is also seen in the follow up run in 2007; however, as different methods to remove instrumental trends in the 2005 run yield vastly different results, the exact shape and periodicity of the 2005 variability remain uncertain. Our re-determined vsini value for 85 Peg A is comparable to previous studies and we provide realistic uncertainties for this parameter. Using these values in combination with simple photometric spot models we are able to reconstruct the observed variations. Conclusions: The null-detection of p-modes in 85 Peg A is consistent with theoretical values for pulsation amplitudes in this star. The detected long-periodic variation must await confirmation by further observations with similar or better precision and long-term stability. If the 11 d periodicity is real, rotational modulation of surface features on one of the components is the most likely explanation.Comment: 11 pages, 9 figures, accepted for publication in A&

New Precision Orbits of Bright Double-Lined Spectroscopic Binaries. I: RR Lyncis, 12 Bootis, and HR 6169

Radial velocities from the 2.1 m telescope at McDonald Observatory supplemented with radial velocities from the coude' feed telescope at KPNO provide new precise orbits for the double-lined spectroscopic binaries RR Lyn (A3/A8/A6), 12 Boo (F8IV), and HR 6169 (A2V). We derive orbital dimensions and minimum masses with accuracies of 0.06 to 0.9 %. The three systems, which have V magnitudes of 5.54, 4.83, and 6.42, respectively, are all sufficiently bright that they are easily within the grasp of modern optical interferometers and so afford the prospect, when our spectroscopic observations are complemented by interferometric observations, of fully-determined orbits, precise masses, and distances. In the case of RR Lyn, which is also a detached eclipsing binary with a well-determined orbital inclination, we are able to determine the semimajor axis of the relative orbit, a = 29.32 +/- 0.04 Rsun, primary and secondary radii of 2.57 +/- 0.02 Rsun and 1.59 +/- 0.03 Rsun, respectively; and primary and secondary masses of 1.927 +/- 0.008 Msun and 1.507 +/- 0.004 Msun, respectively. Comparison of our new systemic velocity determination, gamma = -12.03 +/- 0.04 km/s, with an earlier one, gamma = -11.61 +/- 0.30 km/s, shows no evidence of any change in the systemic velocity in the 40 years separating the two measurements, a null result that neither confirms nor contradicts the presence of the low-mass third component proposed by Khaliullin & Khaliullina (2002). Our spectroscopic orbit of 12 Boo is more precise that that of Boden et al. (2005), but confirms their results about this system. Our analysis of HR 6169 has produced a major improvement in its orbital elements. The minimum masses of the primary and secondary are 2.20 +/- 0.01 and 1.64 +/- 0.02 Msun, respectively.Comment: To appear in the May A

Anti-C2 Antibody ARGX-117 Inhibits Complement in a Disease Model for Multifocal Motor Neuropathy

BACKGROUND AND OBJECTIVES: To determine the role of complement in the disease pathology of multifocal motor neuropathy (MMN), we investigated complement activation, and inhibition, on binding of MMN patient-derived immunoglobulin M (IgM) antibodies in an induced pluripotent stem cell (iPSC)-derived motor neuron (MN) model for MMN. METHODS: iPSC-derived MNs were characterized for the expression of complement receptors and membrane-bound regulators, for the binding of circulating IgM anti-GM1 from patients with MMN, and for subsequent fixation of C4 and C3 on incubation with fresh serum. The potency of ARGX-117, a novel inhibitory monoclonal antibody targeting C2, to inhibit fixation of complement was assessed. RESULTS: iPSC-derived MNs moderately express the complement regulatory proteins CD46 and CD55 and strongly expressed CD59. Furthermore, MNs express C3aR, C5aR, and complement receptor 1. IgM anti-GM1 antibodies in serum from patients with MMN bind to MNs and induce C3 and C4 fixation on incubation with fresh serum. ARGX-117 inhibits complement activation downstream of C4 induced by patient-derived anti-GM1 antibodies bound to MNs. DISCUSSION: Binding of IgM antibodies from patients with MMN to iPSC-derived MNs induces complement activation. By expressing complement regulatory proteins, particularly CD59, MNs are protected against complement-mediated lysis. Yet, because of expressing C3aR, the function of these cells may be affected by complement activation upstream of membrane attack complex formation. ARGX-117 inhibits complement activation upstream of C3 in this disease model for MMN and therefore represents an intervention strategy to prevent harmful effects of complement in MMN

Longitudinal fecal microbiota and volatile metabolomics preceding necrotizing enterocolitis in preterm infants: a case–control study

Alterations in fecal microbiota and volatile organic compound (VOC) profiles of preterm infants have been demonstrated before onset of necrotizing enterocolitis (NEC). However, NEC-specific signatures need to be identified before potential application as predictive biomarker in clinical practice. A prospective multicenter case–control study was conducted to identify preclinical fecal microbiota and VOC profiles of infants that developed NEC. Microbiota analysis (PCR-based IS-pro technique) and VOC analysis (gas chromatography-mass spectrometry) were performed on fecal samples collected up to three days before clinical NEC onset. In 112 infants (56 NEC, 56 matched controls), sufficient number fecal samples were collected for either microbiota or VOC analysis. Prior to NEC onset, Clostridium perfringens (p = 0.023, unadjusted) was more present in infants with NEC, versus controls. VOC analysis showed a clear distinction between fecal profiles of NEC cases and controls (area under the curve = 0.82). Fourteen unique VOC features contributed to this discrimination. Fecal microbiota and VOC profiles may serve as early indicators of NEC, and allow for increased understanding of pathophysiological mechanisms of NEC, but larger validation cohorts are needed before an overarching NEC-specific predictive microbiota-based biomarker can be implemented

A Housing Affordability Standard for the UK

Since 1990 there has been extensive exploration of the meaning of housing affordability by members of the academic, professional and advocacy communities in Britain. These debates have revealed weaknesses in the traditional ratio standard of affordability and led to arguments in support of an alternative, residual income concept of affordability. However, so far there has been only limited success in operationalising and applying the residual income approach in the UK. In the US, by contrast, arguments in support of a residual income approach to housing affordability emerged in the late 1960s and early 1970s, culminating in the formulation of operational standards utilising normative family budgets. This paper draws upon the US experience to formulate a residual income housing affordability standard for the UK that utilises the non-shelter components of the Family Budget Unit (FBU) ‘Low Cost but Acceptable’ budgets as the normative standard for minimum adequate residual income. The paper concludes by suggesting how use of such a ‘shelter’ poverty standard to assess housing affordability problems and needs in the UK might yield results that differ from those based on the ratio standard

Low-mass and sub-stellar eclipsing binaries in stellar clusters

We highlight the importance of eclipsing double-line binaries in our understanding on star formation and evolution. We review the recent discoveries of low-mass and sub-stellar eclipsing binaries belonging to star-forming regions, open clusters, and globular clusters identified by ground-based surveys and space missions with high-resolution spectroscopic follow-up. These discoveries provide benchmark systems with known distances, metallicities, and ages to calibrate masses and radii predicted by state-of-the-art evolutionary models to a few percent. We report their density and discuss current limitations on the accuracy of the physical parameters. We discuss future opportunities and highlight future guidelines to fill gaps in age and metallicity to improve further our knowledge of low-mass stars and brown dwarfs.Comment: 30 pages, 5 figures, no table. Review pape

What is housing affordability? The case for the residual income approach

This article seeks to increase the awareness of and support for the residual income approach to housing affordability indicators and standards, especially in the United States. It begins with an overview of various semantic, substantive, and definitional issues relating to the notion of affordability, leading to an argument supporting the conceptual soundness of the residual income approach. The concept is then briefly set into the historical context of U.S. and British debates on affordability measures. This description is followed by a discussion of two of the principal issues involved in crafting an operational residual income standard: the selection of a normative standard for non-housing items and the treatment of taxes. The article concludes by considering some of the potential implications of the residual income paradigm for the analysis of housing problems and needs, for housing subsidy policy, and for mortgage underwriting practice

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

Background Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. Methods We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). Findings In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]). Interpretation In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. Funding British Journal of Surgery Society

A multiwavelength study of CC Eridani

Radio and optical observations from December 2001 and January 2002 of the active RS CVn-like binary CC Eri are presented. The star was monitored at 4.80 and 8.64 GHz over 3 × 12 h allocations with the Australia Telescope Compact Array on 28 to 30 December 2001. The Anglo-Australian Telescope was used for simultaneous optical spectropolarimetry during a 0.5 h period on 30 December. Data from four nights of broadband photometry gathered around the same period are also included in this present multiwavelength study. The low levels of radio emission were circularly polarised at ~20% with slightly positive spectral indices of ~0.26. Two flare-like increases were observed on successive nights with steep positive spectral indices and no detectable polarisation. Cross-correlation analysis of the 4.80 and 8.64 GHz intensities over the stronger flare showed that the higher frequency emission preceded that at the lower frequency by ~5 min, a result consistent with the propagation of a hydromagnetic disturbance outwards through the corona. On the same night, a significant cross-correlation in the ‘quiescent’ emission indicates the presence of micro-flaring, although its low intensity does not permit the evaluation of a time delay. The emission parameters on the three nights are compatible with a gyrosyncrotron mechanism, in which the radio source becomes optically thick during strong flaring. We develop a simple model, which is based on assuming that the number of radiating electrons is a given function of the magnetic field in the source region, and derive feasible values for the field, source radius, and number of emitting electrons, which are not strongly dependent on the field modelling function or the aspect ratio of the source. Spectropolarimetry demonstrates the presence of a strong surface magnetic field. Optical photometry, covering a sufficient amount of the orbit, indicates a maculation region of significant size (~14° radius). The results help develop a three-dimensional picture of a large stellar magnetically active region and encourage more detailed follow-up multiwavelength studies of this and similar stars