9,409 research outputs found

    A search for water maser emission toward obscured post-AGB star and planetary nebula candidates

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    Water maser emission at 22 GHz is a useful probe to study the transition between the nearly spherical mass-loss in the AGB to a collimated one in the post-AGB phase. In their turn, collimated jets in the post-AGB phase could determine the shape of planetary nebulae (PNe) once photoionization starts. We intend to find new cases of post-AGB stars and PNe with water maser emission, including water fountains or water-maser-emitting PNe. We observed water maser emission in a sample of 133 objects, with a significant fraction being post-AGB and young PN candidate sources with strong obscuration. We detected this emission in 15 of them, of which seven are reported here for the first time. We identified three water fountain candidates: IRAS 17291-2147, with a total velocity spread of ~96 km/s in its water maser components and two sources (IRAS 17021-3109 and IRAS 17348-2906) that show water maser emission outside the velocity range covered by OH masers. We have also identified IRAS 17393-2727 as a possible new water-maser-emitting PN. The detection rate is higher in obscured objects (14%) than in those with optical counterparts (7%), consistent with previous results. Water maser emission seems to be common in objects that are bipolar in the near-IR (43% detection rate). The water maser spectra of water fountain candidates like IRAS 17291-2147 show significantly less maser components than others (e.g., IRAS 18113-2503). We speculate that most post-AGBs may show water maser emission with wide enough velocity spread (> 100 km/s) when observed with enough sensitivity and/or for long enough periods of time. Therefore, it may be necessary to single out a special group of "water fountains", probably defined by their high maser luminosities. We also suggest that the presence of both water and OH masers in a PN is a better tracer of its youth, rather than the presence of just one of these species.Comment: To be published in Astronomy & Astrophysics. 16 pages, 1 figure (spanning 5 pages). This version includes some minor language corrections and fixes some errors in Table

    Observing the Onset of Effective Mass

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    The response of a particle in a periodic potential to an applied force is commonly described by an effective mass which accounts for the detailed interaction between the particle and the surrounding potential. Using a Bose-Einstein condensate of 87-Rb atoms initially in the ground band of an optical lattice, we experimentally show that the initial response of a particle to an applied force is in fact characterized by the bare mass. Subsequently, the particle response undergoes rapid oscillations and only over timescales long compared to that of the interband dynamics is the effective mass observed to be an appropriate description

    Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation

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    A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation.Petróleo Brasileiro S/A — PETROBRASCoordination of Improvement of Higher Education Personnel (CAPES)National Council for Scientific and Technological Development (CNPq

    PANIC: the new panoramic NIR camera for Calar Alto

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    PANIC is a wide-field NIR camera, which is currently under development for the Calar Alto observatory (CAHA) in Spain. It uses a mosaic of four Hawaii-2RG detectors and covers the spectral range from 0.8-2.5 micron(z to K-band). The field-of-view is 30x30 arcmin. This instrument can be used at the 2.2m telescope (0.45arcsec/pixel, 0.5x0.5 degree FOV) and at the 3.5m telescope (0.23arcsec/pixel, 0.25x0.25 degree FOV). The operating temperature is about 77K, achieved by liquid Nitrogen cooling. The cryogenic optics has three flat folding mirrors with diameters up to 282 mm and nine lenses with diameters between 130 mm and 255 mm. A compact filter unit can carry up to 19 filters distributed over four filter wheels. Narrow band (1%) filters can be used. The instrument has a diameter of 1.1 m and it is about 1 m long. The weight limit of 400 kg at the 2.2m telescope requires a light-weight cryostat design. The aluminium vacuum vessel and radiation shield have wall thicknesses of only 6 mm and 3 mm respectively.Comment: This paper has been presented in the SPIE of Astronomical Telescopes and Instrumentation 2008 in Marseille (France

    Use of 2-dimensional speckle-tracking echocardiography to assess left ventricular systolic function in dogs with systemic inflammatory response syndrome

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    Background: Early identification of systolic dysfunction in dogs with systemic inflammatory response syndrome (SIRS) potentially could improve the outcome and decrease mortality. Objective: To compare 2-dimensional speckle tracking (2D-STE) with 2-dimensional (2D) and M-mode echocardiography in the evaluation of systolic function in SIRS dogs. Animals: Seventeen SIRS and 17 healthy dogs. Methods: Prospective observational case-control study. Each dog underwent physical examination, conventional echocardiography, 2D-STE, and C-reactive protein measurement. Results: Dogs with SIRS had lower 2D-STE ejection fraction (X4D-EF; 44 ± 8 versus 53 ± 8; P =.003), endocardial global longitudinal strain (ENDO-G-Long-St; -14.6 ± 3.2 versus -18.5 ± 4.1; P =.003), and normalized left ventricular diameter in diastole (1.38 ± 0.25 versus 1.54 ± 0.17; P =.04) and systole (0.85 ± 0.18 versus 0.97 ± 0.11; P =.03) as compared to healthy dogs. Simpson method of disks (SMOD) right parasternal EF (55 ± 9 versus 60 ± 6; P =.07) and end systolic volume index (ESVI; 23 ± 10 versus 21 ± 6; P =.61), SMOD left apical EF (59 ± 9 versus 59 ± 6; P =.87) and ESVI (20 ± 8 versus 22 ± 6; P =.25), fractional shortening (FS; 34 ± 5 versus 33 ± 4; P =.39), M-mode EF (64 ± 7 versus 62 ± 5; P =.35), and ESVI (23 ± 11 versus 30 ± 9; P =.06) were not significantly different between SIRS and control group, respectively. Conclusion and Clinical Importance: Speckle tracking X4D-EF and ENDO-G-Long-St are more sensitive than 2D and M-Mode FS, EF, and ESVI in detecting systolic impairment in dogs with SIRS

    Possible Patient Early Diagnosis by Ultrasonic Noninvasive Estimation of Thermal Gradients into Tissues Based on Spectral Changes Modeling

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    To achieve a precise noninvasive temperature estimation, inside patient tissues, would open promising research fields, because its clinic results would provide early-diagnosis tools. In fact, detecting changes of thermal origin in ultrasonic echo spectra could be useful as an early complementary indicator of infections, inflammations, or cancer. But the effective clinic applications to diagnosis of thermometry ultrasonic techniques, proposed previously, require additional research. Before their implementations with ultrasonic probes and real-time electronic and processing systems, rigorous analyses must be still made over transient echotraces acquired from well-controlled biological and computational phantoms, to improve resolutions and evaluate clinic limitations. It must be based on computing improved signal-processing algorithms emulating tissues responses. Some related parameters in echo-traces reflected by semiregular scattering tissues must be carefully quantified to get a precise processing protocols definition. In this paper, approaches for non-invasive spectral ultrasonic detection are analyzed. Extensions of author's innovations for ultrasonic thermometry are shown and applied to computationally modeled echotraces from scattered biological phantoms, attaining high resolution (better than 0.1°C). Computer methods are provided for viability evaluation of thermal estimation from echoes with distinct noise levels, difficult to be interpreted, and its effectiveness is evaluated as possible diagnosis tool in scattered tissues like liver

    Safeguarding children in dentistry: 1. Child protection training, experience and practice of dental professionals with an interest in paediatric dentistry

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    * Few dental professionals with child protection training have experience of making referrals. * There is a wide gap in practice between recognising signs of child abuse and neglect and responding effectively. * This may indicate missed opportunities to save children from continuing abuse. * There is a need for improved child protection information, support and training for dental professionals. Abstract Following several highly publicised inquiries into the deaths of children from abuse and neglect, there has been much recent interest in the role and responsibility of all health professionals to protect children at risk of maltreatment. The findings of a postal questionnaire, sent in March 2005 to 789 dentists and dental care professionals with an interest in paediatric dentistry working in varied settings in the UK, are presented in a two-part report and discussed in the context of current multi-agency good practice in safeguarding and promoting the welfare of children. This first part explores reported child protection training, experience and practice. There was a significant gap between recognising signs of abuse and responding effectively: 67% of respondents had suspected abuse or neglect of a child patient at some time in their career but only 29% had ever made a child protection referral. The dental profession is alerted to the need to ensure necessary appropriate action to safeguard children is always taken when child abuse or neglect are suspected
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