1,974 research outputs found
Twenty-One New Light Curves of OGLE-TR-56b: New System Parameters and Limits on Timing Variations
Although OGLE-TR-56b was the second transiting exoplanet discovered, only one
light curve, observed in 2006, has been published besides the discovery data.
We present twenty-one light curves of nineteen different transits observed
between July 2003 and July 2009 with the Magellan Telescopes and Gemini South.
The combined analysis of the new light curves confirms a slightly inflated
planetary radius relative to model predictions, with R_p = 1.378 +/- 0.090 R_J.
However, the values found for the transit duration, semimajor axis, and
inclination values differ significantly from the previous result, likely due to
systematic errors. The new semimajor axis and inclination, a = 0.01942 +/-
0.00015 AU and i = 73.72 +/- 0.18 degrees, are smaller than previously
reported, while the total duration, T_14 = 7931 +/- 38 s, is 18 minutes longer.
The transit midtimes have errors from 23 s to several minutes, and no evidence
is seen for transit midtime or duration variations. Similarly, no change is
seen in the orbital period, implying a nominal stellar tidal decay factor of
Q_* = 10^7, with a three-sigma lower limit of 10^5.7.Comment: 14 pages, 5 figures, accepted to Ap
Lack of Transit Timing Variations of OGLE-TR-111b: A re-analysis with six new epochs
We present six new transits of the exoplanet OGLE-TR-111b observed with the
Magellan Telescopes in Chile between April 2008 and March 2009. We combine
these new transits with five previously published transit epochs for this
planet between 2005 and 2006 to extend the analysis of transit timing
variations reported for this system. We derive a new planetary radius value of
1.019 +/- 0.026 R_J, which is intermediate to the previously reported radii of
1.067 +/- 0.054 R_J (Winn et al. 2007) and 0.922 +/- 0.057 R_J (Diaz et al.
2008). We also examine the transit timing variation and duration change claims
of Diaz et al. (2008). Our analysis of all eleven transit epochs does not
reveal any points with deviations larger than 2 sigma, and most points are well
within 1 sigma. Although the transit duration nominally decreases over the four
year span of the data, systematic errors in the photometry can account for this
result. Therefore, there is no compelling evidence for either a timing or a
duration variation in this system. Numerical integrations place an upper limit
of about 1 M_E on the mass of a potential second planet in a 2:1 mean-motion
resonance with OGLE-TR-111b.Comment: 28 pages, 7 tables, 6 figures. Accepted by Ap
Antemortem diagnosis of asbestosis by screening chest radiograph correlated with postmortem histologic features of asbestosis: a study of 273 cases
BACKGROUND: Accuracy in the clinical diagnosis of asbestosis has significant implications for the future health of affected patients as well as serious medicolegal implications for both patients and asbestos-associated industries. The radiographic gold-standard for diagnosis of asbestosis has been the plain chest radiograph, and in many asbestosis-screening clinics, chest radiograph abnormalities in conjunction with a history of asbestos exposure have been the mainstay of diagnosis. No studies have yet compared the antemortem chest radiographic diagnosis of asbestosis with the subsequent presence of pulmonary fibrosis and lung tissue ferruginous bodies at autopsy. METHODS: Records were reviewed from 273 autopsies performed to investigate asbestosis over an 11-year period. Accrued data included age and gender as well as the presence or absence of the following: occupational exposure to asbestos, antemortem clinical diagnosis of asbestosis by chest radiograph, fibrous pleural plaques, peribronchiolar or interstitial pulmonary fibrosis, ferruginous bodies in histologic sections of lung tissue, and ferruginous bodies in digested lung tissue. RESULTS: 242 cases with the antemortem radiographic diagnosis of asbestosis (study group) were identified. 31 additional autopsies had been requested based on history of asbestos exposure without radiographic documentation of asbestosis (control group). Comparison of the two groups showed a statistically significant increase in the association of chest radiograph-diagnosed asbestosis and the presence at autopsy of pleural plaques (p = 0.0109), peribronchiolar or interstitial pulmonary fibrosis (p = 0.0472), and histologically-diagnostic asbestosis (p = 0.0021). At autopsy, histologically-diagnostic asbestosis was confirmed in only 90 of the 243 study group cases. Comparison of individual parameters within the 242 study group cases showed a statistically significant correlation between the presence of fibrous pleural plaques and histologically-proven pulmonary fibrosis (p = 0.0025) as well as the subsequent histologic diagnosis of asbestosis (p < 0.0001). CONCLUSION: Clinical diagnosis of asbestosis by screening chest radiograph is more predictive of the postmortem presence of fibrous pleural plaques, pulmonary fibrosis, and histologically-proven asbestosis than is occupational exposure history alone. However, chest radiograph-based diagnosis of asbestosis significantly overpredicts the subsequent histologic diagnosis of asbestosis
Ship-board determination of whole-rock (ultra-)trace element concentrations by laser ablation-inductively coupled plasma mass spectrometry analysis of pressed powder pellets aboard the D/V Chikyu
The Oman Drilling Project (OmanDP), performed under the International Continental Scientific Drilling Program (ICDP), is an international scientific research project that undertook drilling at a range of sites in the Semail ophiolite (Oman) to collect core samples spanning the stratigraphy of the ophiolite, from the upper oceanic crust down to the basal thrust. The cores were logged to International Ocean Discovery Program (IODP) standards aboard the D/V Chikyu. During ChikyuOman2018 Leg 3 (July-August 2018), participants described cores from the crust-mantle transition (CM) sites. The main rock types recovered at these sites were gabbros, dunites and harzburgites, rocks typically forming the base of the oceanic crust and the shallow mantle beneath present-day spreading centres. In addition to the core description, selected samples were analysed by X-ray fluorescence spectrometry (XRF) for their chemical compositions, including major, minor and some trace elements. To complement these standard procedures, we developed new approaches to measure ultra-trace element concentrations using a procedure adapted from previous works to prepare fine-grained pressed powder pellets coupled with laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis using instrumentation aboard the D/V Chikyu. First, three (ultra)mafic reference materials were investigated to test and validate our procedure (BHVO-2, BIR-1a and JP-1), and then the procedure was applied to a selection of gabbro and dunite samples from the CM cores to explore the limitations of the method in its current stage of development. The obtained results are in good agreement with preferred values for the reference materials and with subsequent solution replicate analyses of the same samples performed in shore-based laboratories following Leg 3 for the CM samples. We describe this procedure for the determination of 37 minor and (ultra-)trace elements (transition elements and Ga, Li and Large-Ion Lithophile Elements (LILE), Rare Earth Elements (REE), High-Field-Strength Elements (HFSE), U, Th, and Pb) in mafic and ultramafic rocks. The presented method has the major advantage that it allows the determination at sea of the (ultra-)trace element concentrations in a "dry", safe way, without using acid reagents. Our new approach could be extended for other elements of interest and/or be improved to be adapted to other rock materials during future ocean drilling operations aboard the D/V Chikyu and other platforms.This research used samples and/or data provided by the Oman Drilling Project. The Oman Drilling Project (OmanDP) has been possible through co-mingled funds from the International Continental Scientific Drilling Project (ICDP; Peter B. Kelemen, Juerg Matter, Damon A. H. Teagle Lead PIs), the Sloan Foundation – Deep Carbon Observatory (grant no. 2014-3-01, Kele- men PI), the National Science Foundation (grant no. NSF-EAR-
1516300, Kelemen lead PI), NASA – Astrobiology Institute (grant no. NNA15BB02A, Templeton PI), the German Research Founda-tion (DFG: grant no. KO 1723/21-1, Koepke PI), the Japanese Society for the Promotion of Science (JSPS (grant no. 16H06347), Michibayashi PI; and KAKENHI (grant no. 16H02742), Takazawa PI), the European Research Council (Adv: grant no. 669972; Jamveit PI), the Swiss National Science Foundation (SNF: grant no. 20FI21_163073, Früh-Green PI), JAMSTEC, the TAMU-JR Science Operator, and contributions from the Sultanate of Oman Ministry of Regional Municipalities and Water Resources, the Oman Public Authority of Mining, Sultan Qaboos University, CNRS- Univ. Montpellier, Columbia University of New York, and the University of Southampton. Mathieu Rospabé’s participation in onsite and shipboard operations was made possible through a financial support provided by the Centre National de la Recherche
Scientifique-Institut National des Sciences de l’Univers (CNRSINSU), IODP-France (regular fund
Developmentally regulated cleavage of tRNAs in the bacterium Streptomyces coelicolor
The ability to sense and respond to environmental and physiological signals is critical for the survival of the soil-dwelling Gram-positive bacterium Streptomyces coelicolor. Nutrient deprivation triggers the onset of a complex morphological differentiation process that involves the raising of aerial hyphae and formation of spore chains, and coincides with the production of a diverse array of clinically relevant antibiotics and other secondary metabolites. These processes are tightly regulated; however, the genes and signals involved have not been fully elucidated. Here, we report a novel tRNA cleavage event that follows the same temporal regulation as morphological and physiological differentiation, and is growth medium dependent. All tRNAs appear to be susceptible to cleavage; however, there appears to be a bias towards increased cleavage of those tRNAs that specify highly utilized codons. In contrast to what has been observed in eukaryotes, accumulation of tRNA halves in S. coelicolor is not significantly affected by amino acid starvation, and is also not affected by induction of the stringent response or inhibition of ribosome function. Mutants defective in aerial development and antibiotic production exhibit altered tRNA cleavage profiles relative to wild-type strains
Teaching word recognition to children with severe learning difficulties: an exploratory comparison of teaching methods
Background: Some children with severe learning difficulties fail to begin word recognition. For these children there is a need for an effective and appropriate pedagogy. However, conflicting advice can be found regarding this derived from teaching approaches that are not based on a shared understanding of how reading develops or the skills that the non-reader needs to master.
Purpose: In this research, three techniques for teaching word recognition in this context are described and compared: (1) the handle technique, (2) morphing method and (3) word alone. It also discusses whether it is appropriate for such small-scale research to influence pedagogy.
Programme description: The handle technique uses an abstract mnemonic cue used to teach word recognition, and previous research indicates it is more successful than the presentation of words alone. The morphing method transforms a word into a photographic picture and a previous study suggested that it might also be more effective that presenting words alone.
Sample: Six children between 11 and 13 years of age were selected. The criterion for selection was being unable to recognise any words from the British Ability Scales Reading Test. All the children attended a school for children with severe learning difficulties.
Design and methods: A three-condition related design was used. The order in which the conditions were presented was counterbalanced and each child was taught 12 words, four words in each experimental condition. The children encountered each of the three methods and overall each word was taught via each method. Within conditions (teaching methods), the presentation of words was randomised. The number of words that the children could read (without cues) before each session was recorded, following the presentation of the uncued words in a random order. The difference in the number of words recognised between the three conditions was considered using a non-parametric statistical analysis.
Results: The results suggest that the handle approach might be a more effective method of teaching word recognition.
Conclusion: Research in this area is necessarily small in scale. However, it is ongoing and cumulative, and can give insights into potentially beneficial changes in classroom practice
Evaluation of an early detection tool for social-emotional and behavioral problems in toddlers: The Brief Infant Toddler Social and Emotional Assessment - A cluster randomized trial
<p>Abstract</p> <p>Background</p> <p>The prevalence of social-emotional and behavioral problems is estimated to be 8 to 9% among preschool children. Effective early detection tools are needed to promote the provision of adequate care at an early stage. The Brief Infant-Toddler Social and Emotional Assessment (BITSEA) was developed for this purpose. This study evaluates the effectiveness of the BITSEA to enhance social-emotional and behavioral health of preschool children.</p> <p>Methods and Design</p> <p>A cluster randomized controlled trial is set up in youth health care centers in the larger Rotterdam area in the Netherlands, to evaluate the BITSEA. The 31 youth health care centers are randomly allocated to either the control group or the intervention group. The intervention group uses the scores on the BITSEA and cut-off points to evaluate a child's social-emotional and behavioral health and to decide whether or not the child should be referred. The control group provides care as usual, which involves administering a questionnaire that structures the conversation between child health professionals and parents. At a one year follow-up measurement the social-emotional and behavioral health of all children included in the study population will be evaluated.</p> <p>Discussion</p> <p>It is hypothesized that better results will be found, in terms of social-emotional and behavioral health in the intervention group, compared to the control group, due to more adequate early detection, referral and more appropriate and timely care.</p> <p>Trial registration</p> <p>Current Controlled Trials <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2035">NTR2035</a></p
Comparing the effectiveness of monetary versus moral motives in environmental campaigning
Environmental campaigns often promote energy conservation by appealing to economic (for example, lower electricity bills) rather than biospheric concerns (for example, reduced carbon emissions), assuming that people are primarily motivated by economic self-interest. However, people also care about maintaining a favourable view of themselves (they want to maintain a 'positive self-concept'), and may prefer to see themselves as 'green' rather than 'greedy'. Consequently, people may find economic appeals less attractive than biospheric appeals. Across two studies, participants indicated feeling better about biospheric ('Want to protect the environment? Check your car's tire pressure') than economic ('Want to save money? Check your car's tire pressure') tyre-check appeals. In a field experiment, we found that an economic tyre-check appeal ('Do you care about your finances? Get a free tire check') elicited significantly less compliance than parallel biospheric and neutral appeals. Together, these studies discredit the conventional wisdom that appealing to economic self-interest is the best way to secure behaviour change. At least in some cases, our studies suggest, this strategy is not effective.</p
Reliability and Validity of the Dutch Version of the Brief Infant-Toddler Social and Emotional Assessment (BITSEA)
Background: The Brief Infant-Toddler Social and Emotional Assessment (BITSEA) is a relatively new and short (42-item) questionnaire that measures psychosocial problems in toddlers and consists of a Problem and a Competence scale. In this study the reliability and validity of the Dutch version of the BITSEA were examined for the whole group and for gender and ethnicity subgroups. Methods: Parents of 7140 two-year-old children were invited in the study, of which 3170 (44.4%) parents completed the BITSEA. For evaluation of the score distribution, the presence of floor/ceiling effects was determined. The internal consistency (Cronbach's alpha) was evaluated and in subsamples the test-retest, parent-childcare provider interrater reliability and concurrent validity with regard to the Child Behavioral Checklist (CBCL). Discriminative validity was evaluated by comparing scores of parents that worry and parents that do not worry about their child's development. Results: The BITSEA showed no floor or ceiling effects. Psychometric properties of the BITSEA Problem and Competence scale were respectively: Cronbach's alphas were 0.76 and 0.63. Test-retest correlations were 0.75 and 0.61. Interrater reliability correlations were 0.30 and 0.17. Concurrent validity was as hypothesised. The BITSEA was able to discriminate between parents that worry about their child and parents that do not worry. The psychometric properties of the BITSEA were comparable across gender and ethnic background. Conclusion: The results in this large-scale study of a diverse sample support the reliability and validity of the BITSEA Problem scale. The BITSEA Competence scale needs further study. The performance of the BITSEA appears to be similar in subgroups by gender and ethnic background
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