569 research outputs found
Low speed testing of the inlets designed for a tamden-fan V/STOL nacelle
An approximately 0.25 scale model of a tandem fan nacelle, designed for a subsonic V/STOL aircraft, was tested in a Lewis wind tunnel. Model variables included long and short aft inlet cowls and the addition of exterior strakes to the short inlet cowl. Inlet pressure recoveries and distortion were measured at pitch angles to 40 deg and at combinations of pitch and yaw to 30 deg. Airspeeds covered a range to 135 knots (69 m/sec). The short aft inlet with added strakes had the best aerodynamic performance and is considered suitable for the intended V/STOL application
Do Poison Pills Increase Firm Risk?
Management scholars have argued that an active takeover market discourages risk-taking by managers and that takeover defenses serve to counter the risk-reducing pressures of an active takeover market. This study employs the Black and Scholes Option Pricing Model to determine whether or not adoption of poison pill securities increases investor perceptions of firm risk. The results provide evidence that the Option-Implied Standard Deviations of common stock returns increase significantly on the poison pill adoption date, on average. Furthermore, the implied standard deviations remained significantly above pre-adoption levels for several days after the poison pill adoption, suggesting that the perceived increase in firm risk is permanent. These results suggest the poison pills may serve a more constructive role in the governance of publicly traded firms than is generally assumed
Spitzer observations of the HH 1/2 system. The discovery of the counterjet
We present unpublished Spitzer IRAC observations of the HH 1/2 young stellar outow processed
with a high angular resolution deconvolution algorithm, that produces sub-arcsecond (~ 0.6 - 0.8â)
images. In the resulting mid-infrared images, the optically invisible counterjet is detected for the first
time. The counterjet is approximately half as bright as the jet at 4.5 ”m (the IRAC band that best
traces young stellar outows) and has a length of ~ 10â. The NW optical jet itself can be followed back
in the mid-IR to the position of the exciting VLA 1 source. An analysis of the IRAC colors indicates
that the jet/counterjet emission is dominated by collisionally excited H_2 pure rotational lines arising
from a medium with a neutral Hydrogen gas density of ~ 1000-2000 cm^(-3) and a temperature ~ 1500
K. The observed jet/counterjet brightness asymmetry is consistent with an intrinsically symmetric
outow with extinction from a dense, circumstellar structure of ~ 6â size (along the outow axis),
and with a mean visual extinction, A_V ~ 11 mag
Young and Old Adults' Concerns About Morality and Competence
Two experiments were conducted to examine people's sensitivity to person information from the morality domain (relation-oriented) and the competence domain (task & achievement-oriented). In a lexical decision paradigm, the findings from Experiment 1 showed that younger adults were faster to identify person cues (trait words) from the morality than from the competence domain, especially cues that were related to immorality. Experiment 2 compared the responses of younger and older adults. Despite the slower responses of the older adults, the findings indicated that all participants were faster at identifying cues from the morality domain than from the competence domain, with no age interactions. The results from Experiment 2 also suggested that disparate findings in the literature regarding reaction times to morality/competence cues and valence (positive or negative) were a function of word frequency effects. The findings are discussed in terms of people's chronic concern with the moral aspects of others as invariant across the lifespan, given that the morality domain is where interpersonal costs and threats are most likely to be signaled.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45370/1/11031_2004_Article_343706.pd
âI h 8 uâ: Findings from a five-year study of text and e-mail bullying
Copyright @ 2010 British Educational Research Association. The final version of this article is available at the link below.This study charts reports of nasty or threatening text and e-mail messages received by students in academic years 7 and 8 (11-13 years of age) attending 13 secondary schools in the North of England between 2002-2006. Annual surveys were undertaken on behalf of the local education authority (LEA) to monitor bullying. Results indicated that, over five years, the number of pupils receiving one or more nasty or threatening text messages or e-mails increased significantly, particularly among girls. However, receipt of frequent nasty or threatening text and e-mail messages remained relatively stable. For boys, being a victim of direct-physical bullying was associated with receiving nasty or threatening text and e-mail messages; for girls it was being unpopular among peers. Boys received more hate-related messages and girls were primarily the victims of name-calling, Findings are discussed with respect to theoretical and policy developments, and recommendations for future research are offered
A Warm Heart and a Clear Head
Prior studies on the association between weather and psychological changes have produced mixed results. In part, this inconsistency may be because weather's psychological effects are moderated by two important factors: the season and time spent outside. In two correlational studies and an experiment manipulating participants' time outdoors (total N = 605), pleasant weather (higher temperature or barometric pressure) was related to higher mood, better memory, and âbroadenedâ cognitive style during the spring as time spent outside increased. The same relationships between mood and weather were not observed during other times of year, and indeed hotter weather was associated with lower mood in the summer. These results are consistent with findings on seasonal affective disorder, and suggest that pleasant weather improves mood and broadens cognition in the spring because people have been deprived of such weather during the winter.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73377/1/j.1467-9280.2005.01602.x.pd
Near-Infrared Imaging Polarimetry of Young Stellar Objects in rho-Ophiuchi
The results of a near-infrared (J H K LP) imaging linear polarimetry survey
of 20 young stellar objects (YSOs) in rho Ophiuchi are presented. The majority
of the sources are unresolved, with K-band polarizations, P_K < 6 per cent.
Several objects are associated with extended reflection nebulae. These objects
have centrosymmetric vector patterns with polarization discs over their cores;
maximum polarizations of P_K > 20 per cent are seen over their envelopes.
Correlations are observed between the degree of core polarization and the
evolutionary status inferred from the spectral energy distribution. K-band core
polarizations >6 per cent are only observed in Class I YSOs. A 3D Monte Carlo
model with oblate grains aligned with a magnetic field is used to investigate
the flux distributions and polarization structures of three of the rho Oph YSOs
with extended nebulae. A rho proportional to r^(-1.5) power law for the density
is applied throughout the envelopes. The large-scale centrosymmetric
polarization structures are due to scattering. However, the polarization
structure in the bright core of the nebula appears to require dichroic
extinction by aligned non-spherical dust grains. The position angle indicates a
toroidal magnetic field in the inner part of the envelope. Since the measured
polarizations attributed to dichroic extinction are usually <10 per cent, the
grains must either be nearly spherical or very weakly aligned. The higher
polarizations observed in the outer parts of the reflection nebulae require
that the dust grains responsible for scattering have maximum grain sizes <=1.05
microns.Comment: 26 pages. Accepted by MNRAS. Available as online early versio
A CO (J=3-2) Outflow Survey of the Elias 29 Region
We present a 5'x5' integrated intensity map of 12CO (J=3-2) emission from the
rho-Ophiuchi cloud core that traces low-luminosity outflow emission from two
protostars: Elias 29 and, most likely, LFAM 26. The morphology of the outflow
from Elias 29 is bipolar and has a curved axis that traces the S-shaped
symmetry seen in H_2 emission. The outflow from LFAM 26 is a new detection and
oriented in the east/west direction near the plane of the sky with most of the
blue-shifted emission being absorbed by intervening clouds. The outflow axis of
this object also appears to intersect a knot of H_2 emission previously
attributed to Elias 29. LFAM 26 is a low luminosity source (L_bol = 0.06 L_sun)
which, in combination with the observed outflow, makes it a candidate Very Low
Luminosity Object (VeLLO). We derive lower limits to the gas column densities
and energetics for both outflows. The mechanical luminosities for Elias 29 and
LFAM 26 are 6.4 and 10.3 x 10^{-3} L_sun, respectively.Comment: 9 pages, 2 figures, accepted to the ApJ
Digging into NGC 6334I(N): Multiwavelength Imaging of a Massive Protostellar Cluster
We present a high-resolution, multi-wavelength study of the massive
protostellar cluster NGC 6334I(N) that combines new spectral line data from the
Submillimeter Array (SMA) and VLA with a reanalysis of archival VLA continuum
data, 2MASS and Spitzer images. As shown previously, the brightest 1.3 mm
source SMA1 contains substructure at subarcsecond resolution, and we report the
first detection of SMA1b at 3.6 cm along with a new spatial component at 7 mm
(SMA1d). We find SMA1 (aggregate of sources a, b, c, and d) and SMA4 to be
comprised of free-free and dust components, while SMA6 shows only dust
emission. Our 1.5" resolution 1.3 mm molecular line images reveal substantial
hot-core line emission toward SMA1 and to a lesser degree SMA2. We find CH3OH
rotation temperatures of 165\pm 9 K and 145\pm 12 K for SMA1 and SMA2,
respectively. We estimate a diameter of 1400 AU for the SMA1 hot core emission,
encompassing both SMA1b and SMA1d, and speculate that these sources comprise a
>800 AU separation binary that may explain the previously-suggested precession
of the outflow emanating from the SMA1 region. The LSR velocities of SMA1,
SMA2, and SMA4 all differ by 1-2 km/s. Outflow activity from SMA1, SMA2, SMA4,
and SMA6 is observed in several molecules including SiO(5--4) and IRAC 4.5
micron emission; 24 micron emission from SMA4 is also detected. Eleven water
maser groups are detected, eight of which coincide with SMA1, SMA2, SMA4, and
SMA6. We also detect a total of 83 Class I CH3OH 44GHz maser spots which likely
result from the combined activity of many outflows. Our observations paint the
portrait of multiple young hot cores in a protocluster prior to the stage where
its members become visible in the near-infrared.Comment: Accepted to ApJ, 24 pages, a full high resolution version is
available at http://www.cv.nrao.edu/~cbrogan/ms.long.pd
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