325 research outputs found

    Eclipsing Binaries Showing Light Time Effect

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    Four eclipsing binaries, which show apparent changes of period, have been studied with respect to a possible presence of the light time effect. With a least squares method we calculated new light elements of these systems, the mass function of the predicted third body, and its minimum mass. We discuss the probability of the presence of such bodies in terms of mass function, changes in radial velocity and third light in solution of light curves.Comment: 4 pages, 4 figures, 1 table, conference proceeding

    Eclipsing Binaries with Possible Light-Time Effect

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    The period changes of six eclipsing binaries have been studied with focus on the light-time effect. With the least squares method we also calculated parameters of such an effect and properties of the unresolved body in these systems. With these results we discussed the probability of presence of such bodies in the systems with respect to possible confirmation by another method. In two systems we also suggested the hypothesis of fourth body or magnetic activity for explanation of the "second-order variability" after subtraction of the light-time effect of the third body.Comment: 4 pages, 1 figure, 2 tables, conference proceeding

    Gravitationally lensed QSOs in the ISSIS/WSO-UV era

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    Gravitationally lensed QSOs (GLQs) at redshift z = 1-2 play a key role in understanding the cosmic evolution of the innermost parts of active galaxies (black holes, accretion disks, coronas and internal jets), as well as the structure of galaxies at intermediate redshifts. With respect to studies of normal QSOs, GLQ programmes have several advantages. For example, a monitoring of GLQs may lead to unambiguous detections of intrinsic and extrinsic variations. Both kinds of variations can be used to discuss central engines in distant QSOs, and mass distributions and compositions of lensing galaxies. In this context, UV data are of particular interest, since they correspond to emissions from the immediate surroundings of the supermassive black hole. We describe some observation strategies to analyse optically bright GLQs at z of about 1.5, using ISSIS (CfS) on board World Space Observatory-Ultraviolet.Comment: 7 pages, 4 figures, Accepted for publication in Astrophysics & Space Scienc

    On the Path of a Quasi-static Crack in Mode III

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    A method for finding the path of a quasi-static crack growing in a brittle body is presented. The propagation process is modelled by a sequence of discrete steps optimizing the elastic energy released. An explicit relationship between the optimal growing direction and the parameters defining the local elastic field around the tip is obtained for an anti-plane field. This allows to describe a simple algorithm to compute the crack path

    Clinical Conditions “Suggestive of Progressive Supranuclear Palsy”—Diagnostic Performance

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    Background: The Movement Disorder Society diagnostic criteria for progressive supranuclear palsy introduced the diagnostic certainty level “suggestive of progressive supranuclear palsy” for clinical conditions with subtle signs, suggestive of the disease. This category aims at the early identification of patients, in whom the diagnosis may be confirmed as the disease evolves. Objective: To assess the diagnostic performance of the defined clinical conditions suggestive of progressive supranuclear palsy in an autopsy-confirmed cohort. Methods: Diagnostic performance of the criteria was analyzed based on retrospective clinical data of 204 autopsy-confirmed patients with progressive supranuclear palsy and 216 patients with other neurological diseases. Results: The conditions suggestive of progressive supranuclear palsy strongly increased the sensitivity compared to the National Institute of Neurological Disorders and Stroke and Society for Progressive Supranuclear Palsy criteria. Within the first year after symptom onset, 40% of patients with definite progressive supranuclear palsy fulfilled criteria for suggestive of progressive supranuclear palsy. Two-thirds of patients suggestive of progressive supranuclear palsy evolved into probable progressive supranuclear palsy after an average of 3.6 years. Application of the criteria for suggestive of progressive supranuclear palsy reduced the average time to diagnosis from 3.8 to 2.2 years. Conclusions: Clinical conditions suggestive of progressive supranuclear palsy allow earlier identification of patients likely to evolve into clinically possible or probable progressive supranuclear and to have underlying progressive supranuclear palsy pathology. Further work needs to establish the specificity and positive predictive value of this category in real-life clinical settings, and to develop specific biomarkers that enhance their diagnostic accuracy in early disease stages

    A branching, positive relief network in the middle member of the Medusae Fossae Formation, Equatorial Mars - evidence for sapping?

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    The Medusae Fossae Formation (MFF) is a geological formation comprising three geological units (members) spread across five principal lobes. It dominates a quarter of the longitudinal extent of the equatorial region of Mars. Positive relief features referred to as ‘sinuous ridges' (commonly interpreted as inverted paleoflow channel or valley fills) have been observed in the lowest member of the western MFF, but have not been identified within the central and eastern portions of the formation, in the middle and upper members. This paper presents the identification and analysis of a branching, positive relief system which occurs in the central lobe of the MFF in what appears to be an exposure of the middle member. A simple geomorphological map of the system is presented, from which we have adopted the working hypothesis that this is an inverted fill of a branching fluvial channel or valley system. A suite of morphological and topographic evidence supporting this hypothesis is presented, including analysis of the network using a~15 m per pixel digital terrain model derived from a Context Imager (CTX) stereo image pair. The evidence supporting this hypothesis includes: 1) The local slope and topography of the upper surface of the network are consistent with a contributory network, 2) The braided, fan-like form at the termination of the branching network is consistent in morphology with it being a depositional fan at the end of a fluvial system, 3) The terminal fan and surrounding deposits show layering and polygonization, 4) There is strong association between the lower order branches and amphitheater shaped scarps in the depression walls. We evaluate the possible origins of this fluvial system and suggest that seepage sapping is the most probable. Two possible models for the evolution of the network and related features are presented; both require melt of ice within the MFF to form liquid water. We conclude that at least some portions of the Medusae Fossae Formation, if not the entire formation, were once volatile-rich. Finally, we note that our observations do not rule out the case that this network formed before MFF emplacement, and has since been exhumed. However, this conclusion would suggest that much of the surrounding terrain, currently mapped as middle-member MFF, is not in fact MFF material at all

    How to monitor pregnancies complicated by fetal growth restriction and delivery below 32 weeks: a post-hoc sensitivity analysis of the TRUFFLE-study.

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    OBJECTIVES: In the recent TRUFFLE study it appeared that, in pregnancies complicated by fetal growth restriction (FGR) between 26 and 32 weeks, monitoring of the ductus venosus (DV) combined with computerised cardiotocography (cCTG) as a trigger for delivery, increased the chance of infant survival without neurological impairment. However, concerns in interpretation were raised as DV monitoring appeared associated with a non-significant increase in fetal death, and part of the infants were delivered after 32 weeks, after which the study protocol was no longer applied. This secondary sensitivity analysis focuses on women who delivered before 32 completed weeks, and analyses fetal death cases in detail. METHODS: We analysed the monitoring data of 317 women who delivered before 32 weeks, excluding women with absent infant outcome data or inevitable perinatal death. The association of the last monitoring data before delivery and infant outcome was assessed by multivariable analysis. RESULTS: The primary outcome (two year survival without neurological impairment) occurred more often in the two DV groups (both 83%) than in the CTG-STV group (77%), however the difference was not statistically significant (p = 0.21). Nevertheless, in surviving infants 93% was free of neurological impairment in the DV groups versus 85% in the CTG-STV group (p = 0.049). All fetal deaths (n = 7) occurred in women allocated to DV monitoring, which explains this difference. Assessment of the monitoring parameters that were obtained shortly before fetal death in these 7 cases showed an abnormal CTG in only one. Multivariable regression analysis of factors at study entry demonstrated that higher gestational age, larger estimated fetal weight 50th percentile ratio and lower U/C ratio were significantly associated with the (normal) primary outcome. Allocation to the DV groups had a smaller effect, but remained in the model (p < 0.1). Assessment of the last monitoring data before delivery showed that in the CTG-STV group abnormal fetal arterial Doppler was significantly associated with adverse outcome. In contrast, in the DV groups an abnormal DV was the only fetal monitoring parameter that was associated with adverse infant outcome, while fetal arterial Doppler, STV below CTG-group cut-off or recurrent fetal heart rate decelerations were not. CONCLUSIONS: In accordance with the results of the overall TRUFFLE study of the monitoring-intervention management of very early severe FGR we found that the difference in the proportion of infants surviving without neuroimpairment (the primary endpoint) was non-significant when comparing timing of delivery with or without changes in the DV waveform. However, the uneven distribution of fetal deaths towards the DV groups was likely by chance, and among surviving children neurological outcomes were better. Before 32 weeks, delaying delivery until abnormalities in DVPI or STV and/or recurrent decelerations occur, as defined by the study protocol, is therefore probably safe and possibly benefits long-term outcome
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