An Empirically Derived Three-Dimensional Laplace Resonance in the Gliese 876 Planetary System

We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 based solely on Doppler measurements and demanding long-term orbital stability. Our dataset incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, HARPS, and Keck HIRES as well as previously unpublished HIRES velocities. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We find that a four-planet model is preferred over a three-planet model. Next, we apply a Newtonian MCMC algorithm to perform a Bayesian analysis of the planet masses and orbits using an n-body model in three-dimensional space. Based on the radial velocities alone, we find that a 99% credible interval provides upper limits on the mutual inclinations for the three resonant planets ($\Phi_{cb}<6.20^\circ$ for the "c" and "b" pair and $\Phi_{be}<28.5^\circ$ for the "b" and "e" pair). Subsequent dynamical integrations of our posterior sample find that the GJ 876 planets must be roughly coplanar ($\Phi_{cb}<2.60^\circ$ and $\Phi_{be}<7.87^\circ$), suggesting the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model supports the idea of the outer-three planets having undergone significant past disk migration.Comment: 19 pages, 11 figures, 8 tables. Accepted to MNRAS. Posterior samples available at https://github.com/benelson/GJ87

Solvable Systems of Linear Differential Equations

The asymptotic iteration method (AIM) is an iterative technique used to find exact and approximate solutions to second-order linear differential equations. In this work, we employed AIM to solve systems of two first-order linear differential equations. The termination criteria of AIM will be re-examined and the whole theory is re-worked in order to fit this new application. As a result of our investigation, an interesting connection between the solution of linear systems and the solution of Riccati equations is established. Further, new classes of exactly solvable systems of linear differential equations with variable coefficients are obtained. The method discussed allow to construct many solvable classes through a simple procedure.Comment: 13 page

Rest-frame near-infrared sizes of galaxies at cosmic noon: objects in JWST's mirror are smaller than they appeared

Galaxy sizes and their evolution over cosmic time have been studied for decades and serve as key tests of galaxy formation models. However, at $z\gtrsim1$ these studies have been limited by a lack of deep, high-resolution rest-frame infrared imaging that accurately traces galaxy stellar mass distributions. Here, we leverage the new capabilities of the James Webb Space Telescope to measure the 4.4$\mu$m sizes of ${\sim}1000$ galaxies with $\log{\rm{M}_*/\rm{M}_\odot}\ge9$ and $1.0\le z \le 2.5$ from public CEERS imaging in the EGS deep field. We compare the sizes of galaxies measured from NIRCam imaging at 4.4$\mu$m ($\lambda_{\mathrm{rest}}\sim1.6\mu$m) with sizes measured at $1.5\mu$m ($\lambda_{\mathrm{rest}}\sim5500$A). We find that, on average, galaxy half-light radii are $\sim8$% smaller at 4.4$\mu$m than 1.5$\mu$m in this sample. This size difference is markedly stronger at higher stellar masses and redder rest-frame $V-J$ colors: galaxies with ${\rm M}_* \sim 10^{11}\,{\rm M}_\odot$ have 4.4$\mu$m sizes that are $\sim 25$% smaller than their 1.5$\mu$m sizes. Our results indicate that galaxy mass profiles are significantly more compact than their rest-frame optical light profiles at cosmic noon, and demonstrate that spatial variations in age and attenuation are important, particularly for massive galaxies. The trend that we find here impacts our understanding of the size growth and evolution of galaxies, and suggests that previous studies based on rest-frame optical light may not have captured the mass-weighted structural evolution of galaxies. This paper represents a first step towards a new understanding of the morphologies of early massive galaxies enabled by JWST's infrared window into the distant universe.Comment: Accepted to ApJL. 10 pages, 4 figures, 1 table with full size catalog in F150W and F444

Gastroesophageal reflux and PPI exposure alter gut microbiota in very young infants

ImportanceInfants with symptomatic Gastroesophageal reflux are treated with pharmacological therapy that includes proton pump inhibitors (PPI) with clinical improvement. The alterations to gut microbiome profiles in comparison to infants without reflux is not known.ObjectiveTo determine the effect of PPI therapy on gut bacterial richness, diversity, and proportions of specific taxa in infants when compared to infants not exposed to acid suppressive therapy.Design, setting, and participantsThis cohort study was conducted at the Stony Brook Hospital in Stony Brook, NY between February 2016, and June 2019. Infants meeting inclusion criteria were enrolled in a consecutive fashion.ResultsA total of 76 Infants were recruited and 60 were enrolled in the study, Twenty nine infants met clinical criteria for reflux and were treated with PPI therapy: median [IQR] gestation: 38.0 weeks [34.7–39.6 weeks]; median [IQR] birthweight: 2.95 Kg [2.2–3.4]; 14 [46.7%] male) and 29 infant were healthy controls median [IQR] gestation: 39.1 weeks [38–40 weeks]; median [IQR] birthweight: 3.3 Kg [2.2–3.4]; 17 [58.6%] male); 58 stool samples from 58 infants were analyzed. There were differences in Shannon diversity between the reflux and control groups. The reflux group that was exposed to PPI therapy had increased relative abundance of a diverse set of genera belonging to the phylum Firmicutes. On the other hand, the control group microbiota was dominated by Bifidobacterium, and a comparatively lower level of enrichment and abundance of microbial taxa was observed in this group of infants.Conclusions and relevanceWe observed significant differences in both α- and β-diversity of the microbiome, when the two groups of infants were compared. The microbiome in the reflux group had more bacterial taxa and the duration of PPIs exposure was clearly associated with the diversity and abundance of gut microbes. These findings suggest that PPI exposure among infants results in early enrichment of the intestinal microbiome

Where is the UK's pollinator biodiversity? The importance of urban areas for flower-visiting insects

Insect pollinators provide a crucial ecosystem service, but are under threat. Urban areas could be important for pollinators, though their value relative to other habitats is poorly known. We compared pollinator communities using quantified flower-visitation networks in 36 sites (each 1 km2) in three landscapes: urban, farmland and nature reserves. Overall, flower-visitor abundance and species richness did not differ significantly between the three landscape types. Bee abundance did not differ between landscapes, but bee species richness was higher in urban areas than farmland. Hoverfly abundance was higher in farmland and nature reserves than urban sites, but species richness did not differ significantly. While urban pollinator assemblages were more homogeneous across space than those in farmland or nature reserves, there was no significant difference in the numbers of rarer species between the three landscapes. Network-level specialization was higher in farmland than urban sites. Relative to other habitats, urban visitors foraged from a greater number of plant species (higher generality) but also visited a lower proportion of available plant species (higher specialization), both possibly driven by higher urban plant richness. Urban areas are growing, and improving their value for pollinators should be part of any national strategy to conserve and restore pollinators

Reporting HIV in Papua New Guinea: Trends and Omissions from 2000 to 2010

This article presents the findings from a longitudinal content analysis on the reporting of HIV (Human Immunodeficiency Virus) in Papua New Guinea’s two national newspapers—The National and Post-Courier—in 2000, 2005 and 2010. The authors tried to answer two key questions: Did press coverage of the disease increase and did the topics change or remain the same? Data from the content analysis showed that coverage of the disease increased significantly during the ten-year study period, and that the framing of the disease moved beyond representing HIV as purely a health story to one that was linked to socio-economic conditions and cultural practices. The feature stories gradually showed more sensitivity to people living with HIV, while they recognised and challenged the social stigma still associated with the disease in much of the countr

Social movements and public health advocacy in action : the UK people's health movement

There are growing calls within public health for researchers and practitioners working to improve and protect the public's health to become more involved in politics and advocacy. Such a move takes practitioners and researchers beyond the traditional, evidence-based public health paradigm, raising potential dilemmas and risks for those who undertake such work. Drawing on the example of the People's Health Movement, this short paper argues that advocacy and social movements are an essential component of public health's efforts to achieve great health equity. It outlines how the Scottish branch of the People's Health Movement sought to overcome potential tensions between public health evidence and advocacy by developing a regional manifesto for health via transparent and democratic processes which combine empirical and experiential evidence. We suggest that this is an illustrative example of how potential tensions between public health research and advocacy can be overcome, through bottom–up movements of solidarity and action

Modelling disease progression of Multiple Sclerosis in a South Wales cohort

Objectives: To model multiple sclerosis (MS) disease progression and compare disease trajectories by sex, age of onset, and year of diagnosis. Study Design and settings: Longitudinal EDSS scores (20,854 observations) were collected for 1787 relapse-onset MS patients at MS clinics in South Wales and modelled using a multilevel model (MLM). The MLM adjusted for baseline covariates (sex, age of onset, year of diagnosis, and disease modifying treatments (DMTs)), and included interactions between baseline covariates and time variables. Results: The optimal model was truncated at 30 years after disease onset and excluded EDSS recorded within 3 months of relapse. As expected, older age of onset was associated with faster disease progression at 15 years (effect size (ES): 0.75; CI: 0.63, 0.86; P: 2011) progressed more slowly than those diagnosed historically (<2006); (ES: -0.46; CI: -0.75, -0.16; P: 0.006) and (ES: -0.95; CI: -1.20, -0.70; P: <0.001), respectively. Conclusion: We present a novel model of MS outcomes, accounting for the nonlinear trajectory of MS and effects of baseline covariates, validating well-known risk factors (sex and age of onset) associated with disease progression. Also, patients diagnosed more recently progressed more slowly than those diagnosed historically

Cerebral microdialysis and glucopenia in traumatic brain injury: A review

Traditionally, intracranial pressure (ICP) and partial brain tissue oxygenation (PbtO2) have been the primary invasive intracranial measurements used to guide management in patients with severe traumatic brain injury (TBI). After injury however, the brain develops an increased metabolic demand which may require an increment in the oxidative metabolism of glucose. Simultaneously, metabolic, and electrical dysfunction can lead to an inability to meet these demands, even in the absence of ischemia or increased intracranial pressure. Cerebral microdialysis provides the ability to accurately measure local concentrations of various solutes including lactate, pyruvate, glycerol and glucose. Experimental and clinical data demonstrate that such measurements of cellular metabolism can yield critical missing information about a patient's physiologic state and help limit secondary damage. Glucose management in traumatic brain injury is still an unresolved question. As cerebral glucose metabolism may be uncoupled from systemic glucose levels due to the metabolic dysfunction, measurement of cerebral extracellular glucose concentrations could provide more predictive information and prove to be a better biomarker to avoid secondary injury of at-risk brain tissue. Based on data obtained from cerebral microdialysis, specific interventions such as ICP-directed therapy, blood glucose increment, seizure control, and/or brain oxygen optimization can be instituted to minimize or prevent secondary insults. Thus, microdialysis measurements of parenchymal metabolic function provides clinically valuable information that cannot be obtained by other monitoring adjuncts in the standard ICU setting