2,241 research outputs found
Computer program for compressible laminar or turbulent nonsimilar boundary layers
Description of computer program for solving two dimensional and axisymmetric forms of compressible boundary layer equations for continuity, mean momentum, and mean total enthalp
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A short-term longitudinal study of correlates and sequelae of attachment security in autism
In this short-term longitudinal study, thirty preschool-aged children with autism were first observed in Ainsworth’s Strange Situation procedure and, separately, interacting with the primary caregiver in the home. One year later, each child completed both a developmental assessment and an observational assessment of empathic responding. Behaviors typical for children with autism were distinguished from behaviors suggestive of relationally based attachment disorganization. Forty five percent of the children were classified as securely attached. The secure group demonstrated language skills superior to those of the insecurely attached group, concurrently and during the follow-up. Compared to parents of children who were insecurely attached, parents of securely attached children were rated as more sensitive. Compared to both organized insecure and disorganized children, secure children were rated as more responsive to an examiner’s apparent distress during the follow-up relative to their ratings at intake, whereas empathy ratings of children with insecure classifications did not increase. Importantly, attachment security was associated with empathy above and beyond the contribution of children’s language level. These results indicate that the sequelae of attachment security in autism may be similar to those documented for typically developing children.This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute on Deafness and Other Communication Disorders, as part of the Collaborative Programs of Excellence in Autism: [Program Project Grant Number HD-DCD35470] and Wellcome Trust: [Grant Number WT103343MA]
Captured at Millimeter Wavelengths: a Flare from the Classical T Tauri Star DQ Tau
For several hours on 2008 April 19 the T Tauri spectroscopic binary DQ Tau
was observed to brighten, reaching a maximum detected flux of 468 mJy and
likely making it (briefly) the brightest object at 3 mm in the Taurus
star-forming region. We present the light curve of a rarely before observed
millimeter flare originating in the region around a pre-main-sequence star, and
the first from a classical T Tauri star. We discuss the properties and nature
of the flaring behavior in the context of pulsed accretion flows (the current
picture based largely on studies of this object's optically variable spectrum),
as well as magnetospheric re-connection models (a separate theory that predicts
millimeter flares for close binaries of high orbital eccentricity). We believe
that the flare mechanism is linked to the binary orbit, and therefore periodic.
DQ Tau makes a strong case for multi-wavelength follow-up studies, performed in
parallel, of future flares to help determine whether magnetospheric and
dynamical interactions in a proto-binary system are independent.Comment: 4 pages, Accepted for publication in A&A Letter
The infrared properties of the new outburst star IRAS 05436-0007 in quiescent phase
We compiled and investigated the infrared/sub-mm/mm SED of the new outburst
star IRAS 05436-0007 in quiescent phase. The star is a flat-spectrum source,
with an estimated total luminosity of L_bol ~ 5.6 L_sun, typical of low-mass T
Tauri stars. The derived circumstellar mass of 0.5 M_sun is rather high among
low-mass YSOs. The observed SED differs from the SEDs of typical T Tauri stars
and of 4 well-known EXors, and resembles more the SEDs of FU Orionis objects
indicating the presence of a circumstellar envelope. IRAS 05436-0007 seems to
be a Class II source with an age of approximately 4x10^5 yr. In this
evolutionary stage an accretion disk is already fully developed, though a
circumstellar envelope may also be present. Observations of the present
outburst will provide additional knowledge on the source.Comment: 4 pages, 4 figures, to be published in Astronomy & Astrophysics
Letter
Experimental Design for the Gemini Planet Imager
The Gemini Planet Imager (GPI) is a high performance adaptive optics system
being designed and built for the Gemini Observatory. GPI is optimized for high
contrast imaging, combining precise and accurate wavefront control, diffraction
suppression, and a speckle-suppressing science camera with integral field and
polarimetry capabilities. The primary science goal for GPI is the direct
detection and characterization of young, Jovian-mass exoplanets. For plausible
assumptions about the distribution of gas giant properties at large semi-major
axes, GPI will be capable of detecting more than 10% of gas giants more massive
than 0.5 M_J around stars younger than 100 Myr and nearer than 75 parsecs. For
systems younger than 1 Gyr, gas giants more massive than 8 M_J and with
semi-major axes greater than 15 AU are detected with completeness greater than
50%. A survey targeting young stars in the solar neighborhood will help
determine the formation mechanism of gas giant planets by studying them at ages
where planet brightness depends upon formation mechanism. Such a survey will
also be sensitive to planets at semi-major axes comparable to the gas giants in
our own solar system. In the simple, and idealized, situation in which planets
formed by either the "hot-start" model of Burrows et al. (2003) or the core
accretion model of Marley et al. (2007), a few tens of detected planets are
sufficient to distinguish how planets form.Comment: 15 pages, 9 figures, revised after referee's comments and resubmitted
to PAS
Advanced Water Distribution Modeling and Management
Advanced Water Distribution Modeling and Management builds on Haestad Press’ Water Distribution Modeling book. Addressing the modeling process from data collection to application, Advanced Water Distribution Modeling and Management adds extensive material from an international team of experts from both academia and consulting firms and includes topics such as: In-depth coverage of optimization techniques for model calibration, system design, and pump operations. Advanced water quality modeling topics including tank mixing, water quality solution algorithms, sampling techniques, tracer studies, tank design, and maintenance of adequate disinfectant residuals. Integration of SCADA systems with water distribution modeling for estimating model demands, initial conditions, and control settings; forecasting system operations; calibrating extended-period simulation models; streamlining water quality analysis; and estimating water loss during a main break. The essentials of transient analysis including the causes and sources of transients, as well as the potential effects of transients on water distribution systems. Application of GIS technology for skeletonization, demand allocation, and pipe break analysis; discussion of the technological issues that arise when integrating GIS and water distribution modeling; and the current state of the technology. Use of models to assess water system vulnerability and security, respond to emergencies in real-time, simulate contamination events, prioritize physical security improvements, and unravel past contamination events
Ultraviolet number counts of galaxies from Swift UV/Optical Telescope deep imaging of the Chandra Deep Field South
Deep Swift UV/Optical Telescope (UVOT) imaging of the Chandra Deep Field
South is used to measure galaxy number counts in three near ultraviolet (NUV)
filters (uvw2: 1928 A, uvm2: 2246 A, uvw1: 2600 A) and the u band (3645 A).
UVOT observations cover the break in the slope of the NUV number counts with
greater precision than the number counts by the Hubble Space Telescope (HST)
Space Telescope Imaging Spectrograph (STIS) and the Galaxy Evolution Explorer
(GALEX), spanning a range from 21 < m_AB < 25. Number counts models confirm
earlier investigations in favoring models with an evolving galaxy luminosity
function.Comment: 20 pages, 6 figures, accepted to Ap
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