Transit Detection in the MEarth Survey of Nearby M Dwarfs: Bridging the Clean-First, Search-Later Divide

In the effort to characterize the masses, radii, and atmospheres of potentially habitable exoplanets, there is an urgent need to find examples of such planets transiting nearby M dwarfs. The MEarth Project is an ongoing effort to do so, as a ground-based photometric survey designed to detect exoplanets as small as 2 Earth radii transiting mid-to-late M dwarfs within 33 pc of the Sun. Unfortunately, identifying transits of such planets in photometric monitoring is complicated both by the intrinsic stellar variability that is common among these stars and by the nocturnal cadence, atmospheric variations, and instrumental systematics that often plague Earth-bound observatories. Here we summarize the properties of MEarth data gathered so far, and we present a new framework to detect shallow exoplanet transits in wiggly and irregularly-spaced light curves. In contrast to previous methods that clean trends from light curves before searching for transits, this framework assesses the significance of individual transits simultaneously while modeling variability, systematics, and the photometric quality of individual nights. Our Method for Including Starspots and Systematics in the Marginalized Probability of a Lone Eclipse (MISS MarPLE) uses a computationally efficient semi-Bayesian approach to explore the vast probability space spanned by the many parameters of this model, naturally incorporating the uncertainties in these parameters into its evaluation of candidate events. We show how to combine individual transits processed by MISS MarPLE into periodic transiting planet candidates and compare our results to the popular Box-fitting Least Squares (BLS) method with simulations. By applying MISS MarPLE to observations from the MEarth Project, we demonstrate the utility of this framework for robustly assessing the false alarm probability of transit signals in real data. [slightly abridged]Comment: accepted to the Astronomical Journal, 21 pages, 12 figure

Classifying network attack scenarios using an ontology

This paper presents a methodology using network attack ontology to classify computer-based attacks. Computer network attacks differ in motivation, execution and end result. Because attacks are diverse, no standard classification exists. If an attack could be classified, it could be mitigated accordingly. A taxonomy of computer network attacks forms the basis of the ontology. Most published taxonomies present an attack from either the attacker's or defender's point of view. This taxonomy presents both views. The main taxonomy classes are: Actor, Actor Location, Aggressor, Attack Goal, Attack Mechanism, Attack Scenario, Automation Level, Effects, Motivation, Phase, Scope and Target. The "Actor" class is the entity executing the attack. The "Actor Location" class is the Actor‟s country of origin. The "Aggressor" class is the group instigating an attack. The "Attack Goal" class specifies the attacker‟s goal. The "Attack Mechanism" class defines the attack methodology. The "Automation Level" class indicates the level of human interaction. The "Effects" class describes the consequences of an attack. The "Motivation" class specifies incentives for an attack. The "Scope" class describes the size and utility of the target. The "Target" class is the physical device or entity targeted by an attack. The "Vulnerability" class describes a target vulnerability used by the attacker. The "Phase" class represents an attack model that subdivides an attack into different phases. The ontology was developed using an "Attack Scenario" class, which draws from other classes and can be used to characterize and classify computer network attacks. An "Attack Scenario" consists of phases, has a scope and is attributed to an actor and aggressor which have a goal. The "Attack Scenario" thus represents different classes of attacks. High profile computer network attacks such as Stuxnet and the Estonia attacks can now be been classified through the “Attack Scenario” class

A retrospective description of anesthetic medication dosing in overweight and obese children

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108075/1/pan12396.pd

I do think that accessibility is a really major thing that has come [out] of [the] pandemic: The lived experiences of resilience and health-related quality of life among a diverse sample of graduate students during the COVID-19 pandemic.

The COVID-19 pandemic has negatively impacted the mental health and wellbeing of post-secondary students. Resilience has been found to serve as a protective factor against mental distress among students during the pandemic. Despite the plethora of research that exists on post-secondary students during this crisis, most studies exploring students health and resilience are quantitative and lack diversity. To date, the lived experiences of health-related quality of life (HRQOL) and resilience among graduate students representing diversity in age, gender, ethnicity, parental status, university, degree, and faculty during the COVID-19 pandemic remain unknown. As a part of a larger study, the purpose of this qualitative paper was to understand the lived experiences of resilience and HRQOL among a diverse sample of graduate students approximately 18 months into the COVID-19 pandemic in Ontario, Canada. A total of 14 students participated in semi-structured interviews exploring HRQOL domains, factors that supported/undermined participants resilience, challenges/barriers to being resilient, and participants inner strength. Thematic analysis revealed 5 themes: (1) cultural influences on resilience; (2) the role of privilege/power in shaping resilience; (3) how life stage and past experiences support resilience; (4) how the COVID-19 pandemic has undermined the resilience of equity-deserving groups; and (5) the role of disability/chronic pain. This work presents a unique dichotomy between how the COVID-19 pandemic has disrupted the lives of some graduate students, while simultaneously creating opportunities for others to thrive. Findings from this work underscore the importance of creating inclusive and accessible educational spaces to support graduate students resilience and HRQOL currently, and in times of crisis

NLTT 41135: a field M-dwarf + brown dwarf eclipsing binary in a triple system, discovered by the MEarth observatory

We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5 dwarf that was already known to have a wider, slightly more massive common proper motion companion, NLTT 41136, at 2.4 arcsec separation. Analysis of combined-light and radial velocity curves of the system indicates that NLTT 41135B is a 31-34 +/- 3 MJup brown dwarf (where the range depends on the unknown metallicity of the host star) on a circular orbit. The visual M-dwarf pair appears to be physically bound, so the system forms a hierarchical triple, with masses approximately in the ratio 8:6:1. The eclipses are grazing, preventing an unambiguous measurement of the secondary radius, but follow-up observations of the secondary eclipse (e.g. with the James Webb Space Telescope) could permit measurements of the surface brightness ratio between the two objects, and thus place constraints on models of brown dwarfs.Comment: 15 pages, 6 figures, 10 tables, emulateapj format. Accepted for publication in Ap

Poster Introductions II--The Children’s Health and Activity Modification Program (C.H.A.M.P.): Exploring the Impact of a 4-week Lifestyle Intervention on Obese Children and Their Families

C.H.A.M.P., a 4-week day camp for obese children aged 8-14, was held during August 2008. The program included daily physical activity, dietary, and behavioural modification for children, and similarly-themed educational sessions for family members on weekends. The purpose of the present study was to explore the experiences of children and family members who participated in C.H.A.M.P.. Methods: This qualitative study enlisted a trained facilitator to moderate five focus groups immediately following the intervention. Children (n = 12) were allocated to 1 of 2 groups; parents (n = 17) were allocated to 1 of 3 groups. Following a semi-structured interview guide, each session was digitally recorded, transcribed verbatim, and analyzed using inductive content analysis. Results: Preliminary analysis revealed that children enjoyed participating in physical activities progressively and felt that it got easier over time. Children reported that they felt more confident in themselves and their ability to try new activities; using positive self-talk and involving their families in healthy change were emphasized. Dietary themes for children included the importance of eating balanced meals, monitoring serving sizes, and moderation. Parents reported increased confidence in parenting skills, and greater awareness of their influence on family members. Goal setting, trust, and empowerment of children in decision making were also emphasized by parents. Conclusion: This pilot study offers unique insight into the perspectives of obese children and their families. Overall, the program was well-received and impacted participants positively. Results will be discussed in terms of their implications for continued program development and future implementation. Erin Pearson is a doctoral student in the Health and Rehabilitation Sciences Program at the University of Western Ontario. Erin\u27s research interests lie in the areas of health and exercise psychology, as well as the promotion of physical activity in sedentary populations. Currently, Erin\u27s doctoral research focuses on health and wellness pertaining specifically to obesity, behaviour modification, and the use of Motivational Interviewing and Co-Active Life Coaching as health promotion tools. Erin is the Program Coordinator for the Children\u27s Health and Activity Modification Program (C.H.A.M.P.), a group-based lifestyle intervention for obese children at risk for type II diabetes and their families

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ~475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.Peer reviewe

The Transit Light Curve Project. X. A Christmas Transit of HD 17156b

Photometry is presented of the Dec. 25, 2007 transit of HD 17156b, which has the longest orbital period and highest orbital eccentricity of all the known transiting exoplanets. New measurements of the stellar radial velocity are also presented. All the data are combined and integrated with stellar-evolutionary modeling to derive refined system parameters. The planet's mass and radius are found to be 3.212_{-0.082}^{+0.069} Jupiter masses and 1.023_{-0.055}^{+0.070} Jupiter radii. The corresponding stellar properties are 1.263_{-0.047}^{+0.035} solar masses and 1.446_{-0.067}^{+0.099} solar radii. The planet is smaller by 1 sigma than a theoretical solar-composition gas giant with the same mass and equilibrium temperature, a possible indication of heavy-element enrichment. The midtransit time is measured to within 1 min, and shows no deviation from a linear ephemeris (and therefore no evidence for orbital perturbations from other planets). We provide ephemerides for future transits and superior conjunctions. There is an 18% chance that the orbital plane is oriented close enough to edge-on for secondary eclipses to occur at superior conjunction. Observations of secondary eclipses would reveal the thermal emission spectrum of a planet that experiences unusually large tidal heating and insolation variations.Comment: To appear in ApJ [26 pages