Atmospheric Characterization of the Hot Jupiter Kepler-13Ab

Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations observed by warm Spitzer at 4.5 mic and 3.6 mic and a ground-based occultation observation in the Ks band (2.1 mic). We derive a day-side hemisphere temperature of 2,750 +- 160 K as the effective temperature of a black body showing the same occultation depths. Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion. Our analysis shows evidence for a relatively high geometric albedo, Ag= 0.33 +0.04 -0.06. While measured with a simplistic method, a high Ag is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical. We use stellar spectra to determine the dilution, in the four wide bands where occultation was measured, due to the visual stellar binary companion 1.15 +- 0.05" away. The revised stellar parameters measured using these spectra are combined with other measurements leading to revised planetary mass and radius estimates of Mp = 4.94 - 8.09 Mjup and Rp = 1.406 +- 0.038 Rjup. Finally, we measure a Kepler mid-occultation time that is 34.0 +- 6.9 s earlier than expected based on the mid-transit time and the delay due to light travel time, and discuss possible scenarios.Comment: V2: Accepted to ApJ on 2014 April 11. Spitzer photometry and model fitting Matlab pipeline code is publicly available at: http://gps.caltech.edu/~shporer/spitzerphot

Think, Collaborate, Decide, Teach: A Guide for Success

Through recent and documented observations, interviews, and assessments, it has been determined that many educational institutions are in need of intervention in regards to four specific areas, particularly as related to its school leadership team and instructional staff. Proper interventions are needed for institutions to reach their fullest potential and ultimately provide students with the most effective and engaging school experience possible. There are specific challenges related to the ability to effectively make sound decisions, particularly when encountering stressful circumstances that often exist within a complex school environment. This lack of effective decision-making has contributed to shortcomings in the way in which school faculty and staff are working together. This guidebook will present educational institutions with pragmatic ways in which teams can work together to foster collaboration and promote synergy. It will also outline strategies whereby communication may be enhanced to improve student achievement and outcomes. Ultimately, leaders are concerned with the development of critical thinking in the classroom for educators, which will result in behavior issues being solved before administrative intervention. Furthermore, this can reduce or eliminate the pressure on administrators if the situations can be diffused on the classroom level. Therefore, this is the ultimate guide for success: Think, Collaborate, Decide, There are specific challenges related to the ability to effectively make sound decisions, particularly when encountering stressful circumstances that often exist within a complex school environment. This lack of effective decision-making has contributed to shortcomings in the way in which school faculty and staff are working together. This guidebook will present educational institutions with pragmatic ways in which teams can work together to foster collaboration and promote synergy. It will also outline strategies whereby communication may be enhanced to improve student achievement and outcomes. Ultimately, leaders are concerned with the development of critical thinking in the classroom for educators, which will result in behavior issues being solved before administrative intervention. Furthermore, this can reduce or eliminate the pressure on administrators if the situations can be diffused on the classroom level. Therefore, this is the ultimate guide for success: Think, Collaborate, Decide, Teach

The Factory and the Beehive III: PTFEB132.707+19.810, a Low-Mass Eclipsing Binary in Praesepe Observed by PTF and K2

Theoretical models of stars constitute a fundamental bedrock upon which much of astrophysics is built, but large swaths of model parameter space remain uncalibrated by observations. The best calibrators are eclipsing binaries in clusters, allowing measurement of masses, radii, luminosities, and temperatures, for stars of known metallicity and age. We present the discovery and detailed characterization of PTFEB132.707+19.810, a P=6.0 day eclipsing binary in the Praesepe cluster ($\tau$~600--800 Myr; [Fe/H]=0.14$\pm$0.04). The system contains two late-type stars (SpT$_P$=M3.5$\pm$0.2; SpT$_S$=M4.3$\pm$0.7) with precise masses ($M_p=0.3953\pm0.0020$~$M_{\odot}$; $M_s=0.2098\pm0.0014$~$M_{\odot}$) and radii ($R_p=0.363\pm0.008$~$R_{\odot}$; $R_s=0.272\pm0.012$~$R_{\odot}$). Neither star meets the predictions of stellar evolutionary models. The primary has the expected radius, but is cooler and less luminous, while the secondary has the expected luminosity, but is cooler and substantially larger (by 20%). The system is not tidally locked or circularized. Exploiting a fortuitous 4:5 commensurability between $P_{orb}$ and $P_{rot,prim}$, we demonstrate that fitting errors from the unknown spot configuration only change the inferred radii by <1--2%. We also analyze subsets of data to test the robustness of radius measurements; the radius sum is more robust to systematic errors and preferable for model comparisons. We also test plausible changes in limb darkening, and find corresponding uncertainties of ~1%. Finally, we validate our pipeline using extant data for GU Boo, finding that our independent results match previous radii to within the mutual uncertainties (2--3%). We therefore suggest that the substantial discrepancies are astrophysical; since they are larger than for old field stars, they may be tied to the intermediate age of PTFEB132.707+19.810.Comment: Accepted to ApJ; 36 pages, 19 figures, 8 tables in two-column AASTEX6 forma

Walks of molecular motors in two and three dimensions

Molecular motors interacting with cytoskeletal filaments undergo peculiar random walks consisting of alternating sequences of directed movements along the filaments and diffusive motion in the surrounding solution. An ensemble of motors is studied which interacts with a single filament in two and three dimensions. The time evolution of the probability distribution for the bound and unbound motors is determined analytically. The diffusion of the motors is strongly enhanced parallel to the filament. The analytical expressions are in excellent agreement with the results of Monte Carlo simulations.Comment: 7 pages, 2 figures, to be published in Europhys. Let

Transcription-translation coupling: direct interactions of RNA polymerase with ribosomes and ribosomal subunits.

In prokaryotes, RNA polymerase and ribosomes can bind concurrently to the same RNA transcript, leading to the functional coupling of transcription and translation. The interactions between RNA polymerase and ribosomes are crucial for the coordination of transcription with translation. Here, we report that RNA polymerase directly binds ribosomes and isolated large and small ribosomal subunits. RNA polymerase and ribosomes form a one-to-one complex with a micromolar dissociation constant. The formation of the complex is modulated by the conformational and functional states of RNA polymerase and the ribosome. The binding interface on the large ribosomal subunit is buried by the small subunit during protein synthesis, whereas that on the small subunit remains solvent-accessible. The RNA polymerase binding site on the ribosome includes that of the isolated small ribosomal subunit. This direct interaction between RNA polymerase and ribosomes may contribute to the coupling of transcription to translation

The importance of sustained attention in early Alzheimer\u27s disease

Introduction: There is conflicting evidence regarding impairment of sustained attention in early Alzheimer\u27s disease (AD). We examine whether sustained attention is impaired and predicts deficits in other cognitive domains in early AD. Methods: Fifty-one patients with early AD (MMSE \u3e 18) and 15 healthy elderly controls were recruited. The sustained attention to response task (SART) was used to assess sustained attention. A subset of 25 patients also performed tasks assessing general cognitive function (ADAS-Cog), episodic memory (Logical memory scale, Paired Associates Learning), executive function (verbal fluency, grammatical reasoning) and working memory (digit and spatial span). Results: AD patients were significantly impaired on the SART compared to healthy controls (total error β = 19.75, p = 0.027). SART errors significantly correlated with MMSE score (Spearman\u27s rho = −0.338, p = 0.015) and significantly predicted deficits in ADAS-Cog (β = 0.14, p = 0.004). Discussions: Patients with early AD have significant deficits in sustained attention, as measured using the SART. This may impair performance on general cognitive testing, and therefore should be taken into account during clinical assessment, and everyday management of individuals with early AD. Copyright © 2016 John Wiley & Sons, Ltd

Predicting recovery following stroke: deep learning, multimodal data and feature selection using explainable AI

Machine learning offers great potential for automated prediction of post-stroke symptoms and their response to rehabilitation. Major challenges for this endeavour include the very high dimensionality of neuroimaging data, the relatively small size of the datasets available for learning, and how to effectively combine neuroimaging and tabular data (e.g. demographic information and clinical characteristics). This paper evaluates several solutions based on two strategies. The first is to use 2D images that summarise MRI scans. The second is to select key features that improve classification accuracy. Additionally, we introduce the novel approach of training a convolutional neural network (CNN) on images that combine regions-of-interest extracted from MRIs, with symbolic representations of tabular data. We evaluate a series of CNN architectures (both 2D and a 3D) that are trained on different representations of MRI and tabular data, to predict whether a composite measure of post-stroke spoken picture description ability is in the aphasic or non-aphasic range. MRI and tabular data were acquired from 758 English speaking stroke survivors who participated in the PLORAS study. The classification accuracy for a baseline logistic regression was 0.678 for lesion size alone, rising to 0.757 and 0.813 when initial symptom severity and recovery time were successively added. The highest classification accuracy 0.854 was observed when 8 regions-of-interest was extracted from each MRI scan and combined with lesion size, initial severity and recovery time in a 2D Residual Neural Network.Our findings demonstrate how imaging and tabular data can be combined for high post-stroke classification accuracy, even when the dataset is small in machine learning terms. We conclude by proposing how the current models could be improved to achieve even higher levels of accuracy using images from hospital scanners

Spitzer Secondary Eclipse Observations of Five Cool Gas Giant Planets and Empirical Trends in Cool Planet Emission Spectra

In this work we present Spitzer 3.6 and 4.5 micron secondary eclipse observations of five new cool (<1200 K) transiting gas giant planets: HAT-P-19b, WASP-6b, WASP-10b, WASP-39b, and WASP-67b. We compare our measured eclipse depths to the predictions of a suite of atmosphere models and to eclipse depths for planets with previously published observations in order to constrain the temperature- and mass-dependent properties of gas giant planet atmospheres. We find that the dayside emission spectra of planets less massive than Jupiter require models with efficient circulation of energy to the night side and/or increased albedos, while those with masses greater than that of Jupiter are consistently best-matched by models with inefficient circulation and low albedos. At these relatively low temperatures we expect the atmospheric methane to CO ratio to vary as a function of metallicity, and we therefore use our observations of these planets to constrain their atmospheric metallicities. We find that the most massive planets have dayside emission spectra that are best-matched by solar metallicity atmosphere models, but we are not able to place strong constraints on metallicities of the smaller planets in our sample. Interestingly, we find that the ratio of the 3.6 and 4.5 micron brightness temperatures for these cool transiting planets is independent of planet temperature, and instead exhibits a tentative correlation with planet mass. If this trend can be confirmed, it would suggest that the shape of these planets' emission spectra depends primarily on their masses, consistent with the hypothesis that lower-mass planets are more likely to have metal-rich atmospheres.Comment: 16 pages, 14 figures, accepted for publication in Ap