The magnetic activity, winds and planets of young, cool stars

This thesis uses spectropolarimetry to observationally investigate the properties of dynamos and winds of young cool stars, and search for young planets. The techniques of Doppler Imaging and Zeeman Doppler Imaging were used to reconstruct the surface brightness and large-scale magnetic field morphologies of four low-mass weak-line T Tauri stars. The first sample consists of two solar mass stars of different ages, V1095 Sco (1 Myrs) and TWA 9A (10 Myrs). The second sample analysed consists of two 10 Myr old, M-type stars, TWA 25 (0.7 M⊙) and TWA 7 (0.4 M⊙). Taken together, the reconstructed brightness maps of these young cool stars show a wide variety in their morphologies, as do the reconstructed large-scale magnetic fields. These findings are in agreement with the results of the wider Magnetic Topologies of Young Stars and the Survival of close-in giant Exoplanets (MaTYSSE) large programme, of which this thesis is a part. The variations in radial velocity are examined for all four stars, using the brightness information where available to filter out activity jitter, improving the detection limits for close-in giant planets around these stars. In addition to this investigation of pre-main sequence stellar dynamos and young planetary systems, a time series of magnetic field observations of the planet-hosting young star T Boötis spanning more than half a decade - the longest to date - is used to infer changes in the stellar wind, and the resulting potential impacts on the orbiting planet. In overall terms, this thesis demonstrates that spectropolarimetry is a valuable tool for understanding the magnetic dynamos of young cool stars, modelling stellar winds, and for searching for planets in the presence of stellar activity. In future, spectropolarimetry used as part of radial velocity surveys can advance our understanding of the early evolution of cool stars and their planetary systems

The Cutaneous Microbiome and Wounds: New Molecular Targets to Promote Wound Healing

The ecological community of microorganisms in/on humans, termed the microbiome, is vital for sustaining homeostasis. While culture-independent techniques have revealed the role of the gut microbiome in human health and disease, the role of the cutaneous microbiome in wound healing is less defined. Skin commensals are essential in the maintenance of the epithelial barrier function, regulation of the host immune system, and protection from invading pathogenic microorganisms. In this review, we summarize the literature derived from pre-clinical and clinical studies on how changes in the microbiome of various acute and chronic skin wounds impact wound healing tissue regeneration. Furthermore, we review the mechanistic insights garnered from model wound healing systems. Finally, in the face of growing concern about antibiotic-resistance, we will discuss alternative strategies for the treatment of infected wounds to improve wound healing and outcomes. Taken together, it has become apparent that commensals, symbionts, and pathogens on human skin have an intimate role in the inflammatory response that highlights several potential strategies to treat infected, non-healing wounds. Despite these promising results, there are some contradictory and controversial findings from existing studies and more research is needed to define the role of the human skin microbiome in acute and chronic wound healing

Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian Processes

Detecting planetary signatures in radial velocity time-series of young stars is challenging due to their inherently strong stellar activity. However, it is possible to learn information about the properties of the stellar signal by using activity indicators measured from the same stellar spectra used to extract radial velocities. In this manuscript, we present a reanalysis of spectroscopic HARPS data of the young star K2-233, which hosts three transiting planets. We perform a multidimensional Gaussian Process regression on the radial velocity and the activity indicators to characterise the planetary Doppler signals. We demonstrate, for the first time on a real dataset, that the use of a multidimensional Gaussian Process can boost the precision with which we measure the planetary signals compared to a one-dimensional Gaussian Process applied to the radial velocities alone. We measure the semi-amplitudes of K2-233 b, c, and d as 1.31(-0.74)(+0.81), 1.81(-0.67)(+0.71), and 2.72(-0.70)(+0.66) m/s, which translates into planetary masses of 2.4(-1.3)(+1.5), 4.6(-1.7)(+1.8), and 10.3(-2.6)(+2.4), respectively. These new mass measurements make K2-233 d a valuable target for transmission spectroscopy observations with JWST. K2-233 is the only young system with two detected inner planets below the radius valley and a third outer planet above it. This makes it an excellent target to perform comparative studies, to inform our theories of planet evolution, formation, migration, and atmospheric evolution.Comment: Accepted for publication in MNRA

Revisiting K2-233 spectroscopic time-series with multidimensional Gaussian processes

Detecting planetary signatures in radial velocity time-series of young stars is challenging due to their inherently strong stellar activity. However, it is possible to learn information about the properties of the stellar signal by using activity indicators measured from the same stellar spectra used to extract radial velocities. In this manuscript, we present a reanalysis of spectroscopic High Accuracy Radial Velocity Planet Searcher data of the young star K2-233, which hosts three transiting planets. We perform a multidimensional Gaussian process regression on the radial velocity and the activity indicators to characterize the planetary Doppler signals. We demonstrate, for the first time on a real data set, that the use of a multidimensional Gaussian process can boost the precision with which we measure the planetary signals compared to a one-dimensional Gaussian process applied to the radial velocities alone. We measure the semi-amplitudes of K2-233 b, c, and d as 1.31+0.81−0.74, 1.81+0.71−0.67, and 2.72+0.66−0.70 m s−1, which translate into planetary masses of 2.4+1.5−1.3, 4.6+1.8−1.7, and 10.3+2.4−2.6 M⊕, respectively. These new mass measurements make K2-233 d a valuable target for transmission spectroscopy observations with JWST. K2-233 is the only young system with two detected inner planets below the radius valley and a third outer planet above it. This makes it an excellent target to perform comparative studies, to inform our theories of planet evolution, formation, migration, and atmospheric evolution

A function-based typology for Earth’s ecosystems

As the United Nations develops a post-2020 global biodiversity framework for the Convention on Biological Diversity, attention is focusing on how new goals and targets for ecosystem conservation might serve its vision of ‘living in harmony with nature’(1,2). Advancing dual imperatives to conserve biodiversity and sustain ecosystem services requires reliable and resilient generalizations and predictions about ecosystem responses to environmental change and management(3). Ecosystems vary in their biota(4), service provision(5) and relative exposure to risks(6), yet there is no globally consistent classification of ecosystems that reflects functional responses to change and management. This hampers progress on developing conservation targets and sustainability goals. Here we present the International Union for Conservation of Nature (IUCN) Global Ecosystem Typology, a conceptually robust, scalable, spatially explicit approach for generalizations and predictions about functions, biota, risks and management remedies across the entire biosphere. The outcome of a major cross-disciplinary collaboration, this novel framework places all of Earth’s ecosystems into a unifying theoretical context to guide the transformation of ecosystem policy and management from global to local scales. This new information infrastructure will support knowledge transfer for ecosystem-specific management and restoration, globally standardized ecosystem risk assessments, natural capital accounting and progress on the post-2020 global biodiversity framework

Family day care educators : an exploration of their understanding and experiences promoting children\u27s social and emotional wellbeing

This study aimed to explore family day care (FDC) educators&rsquo; knowledge of child social and emotional wellbeing and mental health problems, the strategies used to promote children&rsquo;s wellbeing, and barriers and opportunities for promoting children&rsquo;s social and emotional wellbeing. Thirteen FDC educators participated in individual semi-structured interviews. FDC educators were more comfortable defining children&rsquo;s social and emotional wellbeing than they were in identifying causes and early signs of mental health problems. Strategies used to promote children&rsquo;s mental health were largely informal and dependent on educator skills and capacities rather than a systematic scheme-wide approach. Common barriers to mental health promotion were limited financial resources, a need for more training and hesitance raising child mental health issues with parents. There is a need to build FDC educators&rsquo; knowledge of child social and emotional wellbeing and for tailored mental health promotion strategies in FDC.<br /