Characterization of extrasolar terrestrial planets from diurnal photometric variability

The detection of massive planets orbiting nearby stars has become almost routine, but current techniques are as yet unable to detect terrestrial planets with masses comparable to the Earth's. Future space-based observatories to detect Earth-like planets are being planned. Terrestrial planets orbiting in the habitable zones of stars-where planetary surface conditions are compatible with the presence of liquid water-are of enormous interest because they might have global environments similar to Earth's and even harbor life. The light scattered by such a planet will vary in intensity and colour as the planet rotates; the resulting light curve will contain information about the planet's properties. Here we report a model that predicts features that should be discernible in light curves obtained by low-precision photometry. For extrasolar planets similar to Earth we expect daily flux variations up to hundreds of percent, depending sensitively on ice and cloud cover. Qualitative changes in surface or climate generate significant changes in the predicted light curves. This work suggests that the meteorological variability and the rotation period of an Earth-like planet could be derived from photometric observations. Other properties such as the composition of the surface (e.g., ocean versus land fraction), climate indicators (for example ice and cloud cover), and perhaps even signatures of Earth-like plant life could be constrained or possibly, with further study, even uniquely determined.Comment: Published in Nature. 9 pages including 3 figure

Reduction of Thermal Conductivity in Wafer-Bonded Silicon

Blocks of silicon up to 3-mm thick have been formed by directly bonding stacks of thin wafer chips. These stacks showed significant reductions in the thermal conductivity in the bonding direction. In each sample, the wafer chips were obtained by polishing a commercial wafer to as thin as 36 {micro}m, followed by dicing. Stacks whose starting wafers were patterned with shallow dots showed greater reductions in thermal conductivity. Diluted-HF treatment of wafer chips prior to bonding led to the largest reduction of the effective thermal conductivity, by approximately a factor of 50. Theoretical modeling based on restricted conduction through the contacting dots and some conduction across the planar nanometer air gaps yielded fair agreement for samples fabricated without the HF treatment

Clinical setting influences off-label and unlicensed prescribing in a paediatric teaching hospital

Purpose - To estimate the prevalence of off-label and unlicensed prescribing during 2008 at a major paediatric teaching hospital in Western Australia. Methods - A 12-month retrospective study was conducted at Princess Margaret Hospital using medication chart records randomly selected from 145,550 patient encounters from the Emergency Department, Inpatient Wards and Outpatient Clinics. Patient and prescribing data were collected. Drugs were classified as off-label or unlicensed based on Australian registration data. A hierarchical system of age, indication, route of administration and dosage was used. Drugs were classified according to the Anatomical Therapeutic Chemical Code. Results - A total of 1,037 paediatric patients were selected where 2,654 prescriptions for 330 different drugs were prescribed to 699 patients (67.4%). Most off-label drugs (n = 295; 43.3%) were from the nervous system; a majority of unlicensed drugs were systemic hormonal preparations excluding sex hormones (n = 22, 32.4%). Inpatients were prescribed more off-label drugs than outpatients or Emergency Department patients (p < 0.0001). Most off-label prescribing occurred in infants and children (31.7% and 35.9% respectively) and the highest percentage of unlicensed prescribing (7.2%) occurred in infants (p < 0.0001). There were 25.7% of off-label and 2.6% of unlicensed medications prescribed across all three settings. Common reasons for off-label prescribing were dosage (47.4%) and age (43.2%). Conclusion - This study confirmed off-label and unlicensed use of drugs remains common. Further, that prevalence of both is influenced by the clinical setting, which has implications in regards to medication misadventure, and the need to have systems in place to minimise medication errors. Further, there remains a need for changes in the regulatory system in Australia to ensure that manufacturers incorporate, as it becomes available, evidence regarding efficacy and safety of their drugs in children in the official product information

Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System

The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not anticipated by theoretical work on the formation of planetary systems. Here we report observations and light curve modeling of gravitational microlensing event MACHO-97-BLG-41, which indicates that the lens system consists of a planet orbiting a binary star system. According to this model, the mass ratio of the binary star system is 3.8:1 and the stars are most likely to be a late K dwarf and an M dwarf with a separation of about 1.8 AU. A planet of about 3 Jupiter masses orbits this system at a distance of about 7 AU. If our interpretation of this light curve is correct, it represents the first discovery of a planet orbiting a binary star system and the first detection of a Jovian planet via the gravitational microlensing technique. It suggests that giant planets may be common in short period binary star systems.Comment: 11 pages, with 1 color and 2 b/w Figures included (published version

Orbital Elements and Stellar Parameters of the Active Binary UX Arietis

This is the final version of the article. Available from American Astronomical Society via the DOI in this record.Stellar activity observed as large surface spots, radio flares, or emission lines is often found in binary systems. UX Arietis exhibits these signs of activity, originating on the K0 subgiant primary component. Our aim is to resolve the binary, measure the orbital motion, and provide accurate stellar parameters such as masses and luminosities to aid in the interpretation of the observed phenomena. Using the CHARA six-telescope optical long-baseline array on Mount Wilson, California, we obtained amplitudes and phases of the interferometric visibility on baselines up to 330 m in length, resolving the two components of the binary. We reanalyzed archival Center for Astrophysics spectra to disentangle the binary component spectra and the spectrum of the third component, which was resolved by speckle interferometry. We also obtained new spectra with the Nordic Optical Telescope, and we present new photometric data that we use to model stellar surface spot locations. Both interferometric visibilities and spectroscopic radial velocities are modeled with a spotted primary stellar surface using the Wilson–Devinney code. We fit the orbital elements to the apparent orbit and radial velocity data to derive the distance (52.1 ± 0.8 pc) and stellar masses (MP = 1.30 0.06 M, MS = 1.14 0.06 M). The radius of the primary can be determined to be RP = 5.6 0.1 R and that of the secondary to be RS = 1.6 0.2 R. The equivalent spot coverage of the primary component was found to be 62% with an effective temperature 20% below that of the unspotted surface.We thank Robert Wilson (University of Florida) for providing a custom version of his code to compute images of spotted stellar surfaces and for his help with using it. This work is based upon observations obtained with the Georgia State University (GSU) Center for High Angular Resolution Astronomy (CHARA) array at Mount Wilson Observatory. The CHARA array is supported by the National Science Foundation under grant numbers AST-1211929 and AST-1411654. Institutional support has been provided by the GSU College of Arts and Sciences and the GSU Office of the Vice President for Research and Economic Development. The MIRC instrument at the CHARA array was funded by the University of Michigan. F.B., R.R., and J.D.M. acknowledge support from NSF-AST 1210972 and 1108963. G.T. acknowledges partial support from NSF grant AST-1509375. S.K. acknowledges support from an STFC Rutherford Fellowship (ST/J004030/1) and ERC Starting Grant (grant agreement no. 639889). This work is also based on observations made with the Nordic Optical Telescope (NOT), operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. This research has made use of the SIMBAD database, operated at the CDS, Strasbourg, France. This research has made use of the Jean-Marie Mariotti Center SearchCal service13 codeveloped by FIZEAU and LAOG/IPAG and of the CDS astronomical databases SIMBAD and VIZIER.14 This research has made use of the Washington Double Star Catalog, maintained at the U.S. Naval Observatory. We thank Nicholas Elias II for discussions. We thank Dimitri Pourbaix for maintaining and providing access to the SB9 database of RV measurements of spectroscopic binaries

Neurospora from natural populations: Population genomics insights into the Life history of a model microbial Eukaryote

The ascomycete filamentous fungus Neurospora crassa played a historic role in experimental biology and became a model system for genetic research. Stimulated by a systematic effort to collect wild strains initiated by Stanford geneticist David Perkins, the genus Neurospora has also become a basic model for the study of evolutionary processes, speciation, and population biology. In this chapter, we will first trace the history that brought Neurospora into the era of population genomics. We will then cover the major contributions of population genomic investigations using Neurospora to our understanding of microbial biogeography and speciation, and review recent work using population genomics and genome-wide association mapping that illustrates the unique potential of Neurospora as a model for identifying the genetic basis of (potentially adaptive) phenotypes in filamentous fungi. The advent of population genomics has contributed to firmly establish Neurospora as a complete model system and we hope our review will entice biologists to include Neurospora in their research

Neutralino versus axion/axino cold dark matter in the 19 parameter SUGRA model

We calculate the relic abundance of thermally produced neutralino cold dark matter in the general 19 parameter supergravity (SUGRA-19) model. A scan over GUT scale parameters reveals that models with a bino-like neutralino typically give rise to a dark matter density \Omega_{\tz_1}h^2\sim 1-1000, i.e. between 1 and 4 orders of magnitude higher than the measured value. Models with higgsino or wino cold dark matter can yield the correct relic density, but mainly for neutralino masses around 700-1300 GeV. Models with mixed bino-wino or bino-higgsino CDM, or models with dominant co-annihilation or A-resonance annihilation can yield the correct abundance, but such cases are extremely hard to generate using a general scan over GUT scale parameters; this is indicative of high fine-tuning of the relic abundance in these cases. Requiring that m_{\tz_1}\alt 500 GeV (as a rough naturalness requirement) gives rise to a minimal probably dip in parameter space at the measured CDM abundance. For comparison, we also scan over mSUGRA space with four free parameters. Finally, we investigate the Peccei-Quinn augmented MSSM with mixed axion/axino cold dark matter. In this case, the relic abundance agrees more naturally with the measured value. In light of our cumulative results, we conclude that future axion searches should probe much more broadly in axion mass, and deeper into the axion coupling.Comment: 23 pages including 17 .eps figure

The role of healthcare professionals in encouraging parents to see and hold their stillborn baby: a meta-synthesis of qualitative studies.

Background: Globally, during 2013 there were three million recorded stillbirths. Where clinical guidelines exist some recommend that professionals do not encourage parental contact. The guidance is based on quantitative evidence that seeing and holding the baby is not beneficial for everyone, but has been challenged by bereaved parents' organisations. We aim to inform future guideline development through a synthesis of qualitative studies reporting data relevant to the research question; how does the approach of healthcare professionals to seeing and holding the baby following stillbirth impact parents views and experiences? Methods/Findings: Using a predetermined search strategy of PubMed and PsychINFO we identified robust qualitative studies reporting bereaved parental views and/or experiences relating to seeing and holding their stillborn baby (final search 24 February, 2014). Eligible studies were English language, reporting parental views, with gestational loss >20weeks. Quality was independently assessed by three authors using a validated tool. We used meta-ethnographic techniques to identify key themes and a line of argument synthesis. We included 12 papers, representing the views of 333 parents (156 mothers, 150 fathers, and 27 couples) from six countries. The final themes were: "[Still]birth: Nature of care is paramount", "Real babies: Perfect beauties, monsters and spectres", and "Opportunity of a lifetime lost." Our line-of-argument synthesis highlights the contrast between all parents need to know their baby, with the time around birth being the only time memories can be made, and the variable ability that parents have to articulate their preferences at that time. Thus, we hypothesised that how health professionals approach contact between parents and their stillborn baby demands a degree of active management. An important limitation of this paper is all included studies originated from high income, westernised countries raising questions about the findings transferability to other cultural contexts. We do not offer new evidence to answer the question "Should parents see and hold their stillborn baby?", instead our findings advance understanding of how professionals can support parents to make appropriate decisions in a novel, highly charged and dynamic situation. Conclusions: Guidelines could be more specific in their recommendations regarding parental contact. The role of healthcare professionals in encouraging parents to see and hold their stillborn baby is paramount. Parental choice not to see their baby, apprehension, or uncertainty should be continuously revisited in the hours after birth as the opportunity for contact is fleeting and final

Power to identify a genetic predictor of antihypertensive drug response using different methods to measure blood pressure response

<p>Abstract</p> <p>Background</p> <p>To determine whether office, home, ambulatory daytime and nighttime blood pressure (BP) responses to antihypertensive drug therapy measure the same signal and which method provides greatest power to identify genetic predictors of BP response.</p> <p>Methods</p> <p>We analyzed office, home, ambulatory daytime and nighttime BP responses in hypertensive adults randomized to atenolol (N = 242) or hydrochlorothiazide (N = 257) in the Pharmacogenomic Evaluation of Antihypertensive Responses Study. Since different measured BP responses may have different predictors, we tested the "same signal" model by using linear regression methods to determine whether known predictors of BP response depend on the method of BP measurement. We estimated signal-to-noise ratios and compared power to identify a genetic polymorphism predicting BP response measured by each method separately and by weighted averages of multiple methods.</p> <p>Results</p> <p>After adjustment for pretreatment BP level, known predictors of BP response including plasma renin activity, race, and sex were independent of the method of BP measurement. Signal-to-noise ratios were more than 2-fold greater for home and ambulatory daytime BP responses than for office and ambulatory nighttime BP responses and up to 11-fold greater for weighted averages of all four methods. Power to identify a genetic polymorphism predicting BP response was directly related to the signal-to-noise ratio and, therefore, greatest with the weighted averages.</p> <p>Conclusion</p> <p>Since different methods of measuring BP response to antihypertensive drug therapy measure the same signal, weighted averages of the BP responses measured by multiple methods minimize measurement error and optimize power to identify genetic predictors of BP response.</p