Observational evidence for a metal rich atmosphere on the super-Earth GJ1214b

We report observations of two consecutive transits of the warm super-Earth exoplanet GJ1214b at 3.6 and 4.5 microns with the Infrared Array Camera instrument on-board the Spitzer Space Telescope. The two transit light curves allow for the determination of the transit parameters for this system. We find these paremeters to be consistent with the previously determined values and no evidence for transit timing variations. The main investigation consists of measuring the transit depths in each bandpass to constrain the planet's transmission spectrum. Fixing the system scale and impact parameters, we measure R_p/R_star=0.1176 (+0.0008/-0.0009) and 0.1163 (+0.0010/-0.0008) at 3.6 and 4.5 microns, respectively. Combining these data with the previously reported MEarth Observatory measurements in the red optical yields constraints on the GJ1214b's transmission spectrum and allows us to rule-out a cloud-free, solar composition (i.e., hydrogen-dominated) atmosphere at 4.5 sigma confidence. This independently confirms a recent finding that was based on a measurement of the planet's transmission spectrum using the VLT. The Spitzer, MEarth, and VLT observations together yield a remarkably flat transmission spectrum over the large wavelength domain spanned by the data. Consequently, cloud-free atmospheric models require more than 30% metals (assumed to be in the form of H2O by volume to be consistent with all the observations.Comment: Accepted for publication in ApJL. 13 pages, 3 figures, 1 tabl

Risk, Overdiagnosis and Ethical Justifications

Wendy Rogers was supported by Future Fellowship (FT130100346) from the Australian Research Council and a 2018 Residency from the Brocher Foundation. Stacy Carter was supported by National Health and Medical Research Council Centre for Research Excellence 1104136 and a 2018 Residence from the Brocher Foundation. This study was funded by FT130100346 from the Australian Research Council (Rogers) and CRE 1104136 from the National Health and Medical Research Council (Carter), and Rogers and Carter both received support in the form of a 2018 month-long residency at the Brocher Foundation, Switzerland.Peer reviewedPublisher PD

First impressions in familiar eyewitness identifications improve accuracy in target absent lineups

76 leaves : ill. (chiefly col.) ; 29 cm.Includes abstract and appendices.Includes bibliographical references (leaves 55-67).There is evidence in the literature suggesting first impressions, though resilient, can be swayed by additional information (Baker, ten Brinke, & Porter, 2013). The purpose of this research is to investigate whether first impressions influence decisions when the target is familiar to the eyewitness, when utilizing a target-absent identification line-up. Results showed that participants in familiar conditions who received information had higher accuracy rates in comparison to individuals who received no information when making a decision. It was also found that confidence significantly fell in familiar conditions when the participant misidentified. Implications suggest the first impressions the eyewitness has does not impact the accuracy outcomes, but rather any past knowledge about the familiar individual may improve target-absent lineup accuracy. There may be some flexibility when it comes to confidence ratings, seeing a decline in a confidence rating, may allow investigators to assess accuracy in a familiar suspect situation

TheRole of the Insular Cortex in Rodent Social Affective Behavior:

Thesis advisor: John P. ChristiansonIn social species, animals must detect, evaluate and respond to the states of other individuals in their group. A constellation of gestures, vocalizations, and chemosignals enable animals to convey affect and arousal to others in nuanced, multisensory ways. Observers integrate such social information with environmental cues and internal physiology to general social behavioral responses via a process called social decision-making. The mechanisms and anatomical correlates of social decision-making, particularly those that allow behavioral responses to others’ emotional states, are not fully known. Therefore, the objective of this dissertation is to broaden the anatomical understanding of social decision-making by investigating the role of the insular cortex in social behaviors that depend upon others’ emotional state. Using a novel behavioral paradigm, I present causal evidence that implicates the insular cortex and its projections to the nucleus accumbens in social affective behavior. These findings are consistent with evidence from the literature that suggests insular cortex is positioned to convey sensory cues to social brain structures to produce flexible and appropriate behavioral responses to social affective cues.Thesis (PhD) — Boston College, 2019.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Psychology

High Resolution, Differential, Near-infrared Transmission Spectroscopy of GJ 1214b

The nearby star GJ 1214 hosts a planet intermediate in radius and mass between Earth and Neptune, resulting in some uncertainty as to its nature. We have observed this planet, GJ 1214b, during transit with the high-resolution, near-infrared NIRSPEC spectrograph on the Keck II telescope, in order to characterize the planet's atmosphere. By cross-correlating the spectral changes through transit with a suite of theoretical atmosphere models, we search for variations associated with absorption in the planet atmosphere. Our observations are sufficient to rule out tested model atmospheres with wavelength-dependent transit depth variations >5e-4 over the wavelength range 2.1 - 2.4 micron. Our sensitivity is limited by variable slit loss and telluric transmission effects. We find no positive signatures but successfully rule out a number of plausible atmospheric models, including the default assumption of a gaseous, H-dominated atmosphere in chemical equilibrium. Such an atmosphere can be made consistent if the absorption due to methane is reduced. Clouds can also render such an atmosphere consistent with our observations, but only if they lie higher in the atmosphere than indicated by recent optical and infrared measurements. When taken in concert with constraints from other groups, our results support a consensus model in which the atmosphere of GJ 1214b contains significant H and He, but where methane is depleted. If this depletion is the result of photochemical processes, it may also produce a haze that suppresses spectral features in the optical.Comment: 32 pages, 15 figures, preprint, accepted to ApJ, responded to referee's comments. Comments welcom

Compositional Constraints on the Best Characterized Rocky Exoplanet, Kepler-36 b

Kepler-36 is an extreme planetary system, consisting of two transiting sub-Neptune-size planets orbiting around a sub-giant star with periods of 13.84 and 16.24 days. Mutual gravitational interactions between the two planets perturb the planets' transit times, allowing the planets' masses to be measured. Despite the similarity of their masses and orbital radii, the planets show a stark contrast in their mean densities: the inner planet (Kepler-36 b) is more than eight times as dense as its outer companion planet (Kepler-36 c). We perform a photo-dynamical analysis of the Kepler-36 system based on more than three years of Kepler photometry. With N-body integrations of initial conditions sampled from the photo-dynamical fits, we further refine the properties of the system by ruling out solutions that show large scale instability within 5 billion days. Ultimately, we measure the planets' masses with 4.2% precision and the planets' radii with 1.8% precision. Kepler-36 b is the rocky exoplanet with the most precisely measured mass and radius. Kepler-36 b's mass and radius are consistent with an Earth-like composition, whereas an iron-enhanced Mercury-like composition is ruled out

The challenge of overdiagnosis begins with its definition

Overdiagnosis means different things to different people. S M Carter and colleagues argue that we should use a broad term such as too much medicine for advocacy and develop precise, case by case definitions of overdiagnosis for research and clinical purposes The implicit social contract underpinning healthcare is that it will reduce illness and preventable death and improve quality of life. But sometimes these promises are not delivered. Sometimes health services take people who don’t need intervention, subject them to tests, label them as sick or at risk, provide unnecessary treatments, tell them to live differently, or insist on monitoring them regularly.1 These interventions don’t improve things for people; they produce complications or illness, reduce quality of life, or even cause premature death. Active health intervention is not always a good thing: it can be “too much medicine,” or produce what is often called overdiagnosis. Although the concept of overdiagnosis has been described in the literature for nearly 50 years in relation to cancer screening,2 3 it was Welch and colleagues’ 2011 book, Overdiagnosed: Making People Sick in the Pursuit of Health, that popularised the term.4 Overdiagnosis is now an acknowledged problem for patients, clinicians, researchers, and policymakers; it is discussed in journals5 6 7 and at specialist conferences8 and addressed through policy and practice initiatives.9 10 11 There is, however, no formal, agreed definition of overdiagnosis. Rather, the word has become a banner under which disparate people with similar general concerns can unite. This vagueness and breadth allows the appearance of unity but does not serve the more exacting demands of research and healthcare. Here we examine the meanings of overdiagnosis more closely and discuss related challenges for healthcare professionals, patients, and researchers. If overdiagnosis is to be understood and mitigated, the broad concept should be subdivided into different problems and its ethical dimensions better acknowledged.NHMR

The ethical, legal and social implications of using artificial intelligence systems in breast cancer care

Breast cancer care is a leading area for development of artificial intelligence (AI), with applications including screening and diagnosis, risk calculation, prognostication and clinical decision-support, management planning, and precision medicine. We review the ethical, legal and social implications of these developments. We consider the values encoded in algorithms, the need to evaluate outcomes, and issues of bias and transferability, data ownership, confidentiality and consent, and legal, moral and professional responsibility. We consider potential effects for patients, including on trust in healthcare, and provide some social science explanations for the apparent rush to implement AI solutions. We conclude by anticipating future directions for AI in breast cancer care. Stakeholders in healthcare AI should acknowledge that their enterprise is an ethical, legal and social challenge, not just a technical challenge. Taking these challenges seriously will require broad engagement, imposition of conditions on implementation, and pre-emptive systems of oversight to ensure that development does not run ahead of evaluation and deliberation. Once artificial intelligence becomes institutionalised, it may be difficult to reverse: a proactive role for government, regulators and professional groups will help ensure introduction in robust research contexts, and the development of a sound evidence base regarding real-world effectiveness. Detailed public discussion is required to consider what kind of AI is acceptable rather than simply accepting what is offered, thus optimising outcomes for health systems, professionals, society and those receiving care

Precise Particle Tracking Against a Complicated Background: Polynomial Fitting with Gaussian Weight

We present a new particle tracking software algorithm designed to accurately track the motion of low-contrast particles against a background with large variations in light levels. The method is based on a polynomial fit of the intensity around each feature point, weighted by a Gaussian function of the distance from the centre, and is especially suitable for tracking endogeneous particles in the cell, imaged with bright field, phase contrast or fluorescence optical microscopy. Furthermore, the method can simultaneously track particles of all different sizes, and allows significant freedom in their shape. The algorithm is evaluated using the quantitative measures of accuracy and precision of previous authors, using simulated images at variable signal-to-noise ratios. To these we add a new test of the error due to a non-uniform background. Finally the tracking of particles in real cell images is demonstrated. The method is made freely available for non-commencial use as a software package with a graphical user-inferface, which can be run within the Matlab programming environment