5,459 research outputs found

    OH-selected AGB and post-AGB stellar objects II.Blue versus red evolution off the AGB

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    Using objects found in a systematic survey of the galactic Plane in the 1612-MHz OH line, we discuss in detail two ``sequences'' of post-AGB evolution, a red and a blue. We argue that the red and the blue groups separate by initial mass at 4Msun, based on evolutionary-sequence turn-off colours, spectral energy distributions, outflow velocities and scaleheight. The higher-mass (blue) objects may have earlier AGB termination. The lower-mass (red) objects undergo very sudden reddening for IRAS colour R21\sim1.2; these sources must all undergo a very similar process at AGB termination. The transition colour corresponds to average initial masses of 1.7Msun. A combined IRAS-MSX colour proves a very sensitive tool to distinguish lower-mass, early post-AGB objects from sources still on the AGB and also to distinguish more evolved post-AGB objects from star-forming regions. The high-mass blue objects are the likely precursors of bipolar planetary nebulae, whereas the low-mass red objects will evolve into elliptical planetary nebulae.Comment: 12 pages, LaTex, 7 figures (1 colour), AJ (accepted

    HST Snapshot Survey of Post-AGB Objects

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    The results from a Hubble Space Telescope (HST) snapshot survey of post-AGB objects are shown. The aim of the survey is to complement existing HST images of PPN and to connect various types of nebulosities with physical and chemical properties of their central stars. Nebulosities are detected in 15 of 33 sources. Images and photometric and geometric measurements are presented. For sources with nebulosities we see a morphological bifurcation into two groups, DUPLEX and SOLE, as previous studies have found. We find further support to the previous results suggesting that this dichotomy is caused by a difference in optical thickness of the dust shell. The remaining 18 sources are classified as stellar post-AGB objects, because our observations indicate a lack of nebulosity. We show that some stellar sources may in fact be DUPLEX or SOLE based on their infrared colors. The cause of the differences among the groups are investigated. We discuss some evidence suggesting that high progenitor-mass AGB stars tend to become DUPLEX post-AGB objects. Intermediate progenitor-mass AGB stars tend to be SOLE post-AGB objects. Most of the stellar sources probably have low mass progenitors and do not seem to develop nebulosities during the post-AGB phase and therefore do not become planetary nebulae.Comment: 21 pages, 11 figure

    Anterolateral proximal tibial opening wedge osteotomy for biplanar correction in genu valgum recurvatum using patient specific instrumentation (PSI):A technical note

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    BACKGROUND: Biplanar anterolateral proximal tibial opening wedge osteotomy has been described as successful for patients with combined recurvatum and valgus alignment. As it is a correction in two planes, it is a technically demanding procedure. We report the use of a novel technique with patient specific instrumentation (PSI) guides for different steps, aiming to reduce the complexity of this procedure. METHODS: One patient was treated for genu valgum recurvatum. A virtual surgical plan was made. A two-step PSI approach was used, consisting of an osteotomy guide and a repositioning guide and a custom trial wedges. RESULTS: Follow-up showed full function and improved VAS and KOOS scores. A neutral alignment was achieved. There was 2.76 degrees less varus compared to pre-operative planning, 1.24 degrees of excess slope and a rotational difference of 0.10 degrees. Saw plane accuracy was within 1 mm. CONCLUSIONS: PSI is a recent technical addition to HTOs as a modality to improve accuracy and reduce surgical complexity. Pre-planning and PSI use in an anterolateral opening wedge PTO allowed for an accurate and reproducible biplanar correction in genu valgum recurvatum. Accuracy was comparable to PSI use in lateral open wedge high tibial osteotomies

    An evolutionary catalogue of Galactic post-AGB and related objects

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    With the ongoing AKARI infrared sky survey, of much greater sensitivity than IRAS, a wealth of post-AGB objects may be discovered. It is thus time to organize our present knowledge of known post-AGB stars in th galaxy with a view to using it to search for new post-AGB objects among AKARI sources. We searched the literature available on the NASA Astrophysics Data System up to 1 October 2006, and defined criteria for classifying sources into three categories: "very likely", "possible" and "disqualified" post-AGB objects. The category of "very likely" post-AGB objects is made up of several classes. We have created an evolutionary, on-line catalogue of Galactic post-AGB objects, to be referred to as "The Torun catalogue of Galactic post-AGB and related objects". The present version of the catalogue contains 326 "very likely", 107 "possible" and 64 "disqualified" objects. For the very likely post-AGB objects, the catalogue gives the available optical and infrared photometry, infrared spectroscopy and spectral types, and links to finding charts and bibliography.Comment: 9 pages, 6 figures, accepted for publication in A&

    Actief randenbeheer Drenthe lijkt effect te hebben

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    Via monitoring inzicht krijgen in het effect van actief randenbeheer op de oppervlaktewaterkwaliteit en de biodiversiteit in het landelijk gebied en op de inpasbaarheid op de agrarische bedrijven in een bepaald gebied. Dat was het doel van het pilotprogramma ‘Actief Randenbeheer Drenthe’: een initiatief van de Provincie Drenthe, LTO-Noord en de waterschappen Hunze en Aa’s en Velt en Vecht, in het zuidoostelijk deel van Drenthe. Uitvoerende partijen zijn Royal Haskoning, Praktijkonderzoek Plant & Omgeving van Wageningen UR en enkele agrarische bedrijven. Het programma begon in januari 2006 en is in november 2008 afgesloten. De totale duur van de meetperiode bedroeg 27 maande

    The clinical effectiveness of concise cognitive behavioral therapy with or without pharmacotherapy for depressive and anxiety disorders; a pragmatic randomized controlled equivalence trial in clinical practice

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    Background: Depressive and anxiety disorders contribute to a high disease burden. This paper investigates whether concise formats of cognitive behavioral- and/or pharmacotherapy are equivalent with longer standard care in the treatment of depressive and/or anxiety disorders in secondary mental health care. Methods: A pragmatic randomized controlled equivalence trial was conducted at five Dutch outpatient Mental Healthcare Centers (MHCs) of the Regional Mental Health Provider (RMHP) \u27Rivierduinen\u27. Patients (aged 18-65 years) with a mild to moderate anxiety and/or depressive disorder, were randomly allocated to concise or standard care. Data were collected at baseline, 3, 6 and 12 months by Routine Outcome Monitoring (ROM). Primary outcomes were the Brief Symptom Inventory (BSI) and the Web Screening Questionnaire (WSQ). We used Generalized Estimating Equations (GEE) to assess outcomes. Results: Between March 2010 and December 2012, 182 patients, were enrolled (n = 89 standard care; n = 93 concise care). Both intention-to-treat and per-protocol analyses demonstrated equivalence of concise care and standard care at all time points. Severity of illness reduced, and both treatments improved patient\u27s general health status and subdomains of quality of life. Moreover, in concise care, the beneficial effects started earlier. Discussion: Concise care has the potential to be a feasible and promising alternative to longer standard secondary mental health care in the treatment of outpatients with a mild to moderate depressive and/or anxiety disorder. For future research, we recommend adhering more strictly to the concise treatment protocols to further explore the beneficial effects of the concise treatment

    Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry

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    A drop impacting on a solid surface deforms before the liquid makes contact with the surface. We directly measure the time evolution of the air layer profile under the droplet using high-speed color interferometry, obtaining the air layer thickness before and during the wetting process. Based on the time evolution of the extracted profiles obtained at multiple times, we measure the velocity of air exiting from the gap between the liquid and the solid, and account for the wetting mechanism and bubble entrapment. The present work offers a tool to accurately measure the air layer profile and quantitatively study the impact dynamics at a short time scale before impact

    Proton Motive Force-Dependent Hoechst 33342 Transport by the ABC Transporter LmrA of Lactococcus lactis

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    The fluorescent compound Hoechst 33342 is a substrate for many multidrug resistance (MDR) transporters and is widely used to characterize their transport activity. We have constructed mutants of the adenosine triphosphate (ATP) binding cassette (ABC)-type MDR transporter LmrA of Lactococcus lactis that are defective in ATP hydrolysis. These mutants and wild-type LmrA exhibited an atypical behavior in the Hoechst 33342 transport assay. In membrane vesicles, Hoechst 33342 transport was shown to be independent of the ATPase activity of LmrA, and it was not inhibited by orthovanadate but sensitive to uncouplers that collapse the proton gradient and to N,N'-dicyclohexylcarbodiimide, an inhibitor of the F0F1-ATPase. In contrast, transport of Hoechst 33342 by the homologous, heterodimeric MDR transporter LmrCD showed a normal ATP dependence and was insensitive to uncouplers of the proton gradient. With intact cells, expression of LmrA resulted in an increased rate of Hoechst 33342 influx while LmrCD caused a decrease in the rate of Hoechst 33342 influx. Cellular toxicity assays using a triple knockout strain, i.e., L. lactis ΔlmrA ΔlmrCD, demonstrate that expression of LmrCD protects cells against the growth inhibitory effects of Hoechst 33342, while in the presence of LmrA, cells are more susceptible to Hoechst 33342. Our data demonstrate that the LmrA-mediated Hoechst 33342 transport in membrane vesicles is influenced by the transmembrane pH gradient due to a pH-dependent partitioning of Hoechst 33342 into the membrane.
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