2,646 research outputs found
The role of dispositional factors in moderating message framing effects
Objective: Health messages can be framed in terms of the benefits of adopting a recommendation (gain frame) or the costs of not adopting a recommendation (loss frame). In recent years, research has demonstrated that the relative persuasiveness of gain and loss frames can depend on a variety of dispositional factors. This article synthesizes this growing literature to develop our understanding of the moderators of framing. Method: A systematic review of published literature on gain and loss framing was conducted. Articles were retrieved that tested the interaction between framing and moderators representing individual differences in how people are predisposed to think, feel, and behave. The significance and direction of framing main effects and interactions were noted and effect size data extracted where available. Results: Forty-seven reports published between January 1990 and January 2012 were retrieved that reported on 50 unique experiments testing 23 different moderators. Significant interactions with typically small to medium simple main effect sizes were found in 37 of the 50 studies. Consistent interactions were found for factors such as ambivalence, approach–avoidance motivation, regulatory focus, need for cognition, and self-efficacy beliefs. Less consistent effects were found for perceived riskiness of activity, issue involvement, and perceived susceptibility/severity. Conclusion: The relative effectiveness of gain- or loss-framed messages can depend on the disposition of the message recipient. Tailoring the frame to the individual therefore has the potential to maximize message persuasiveness
Periodic photometric variability of the brown dwarf Kelu-1
We have detected a strong periodicity of 1.80+/-0.05 hours in photometric
observations of the brown dwarf Kelu-1. The peak-to-peak amplitude of the
variation is ~1.1% (11.9+/-0.8 mmag) in a 41nm wide filter centred on 857nm and
including the dust/temperature sensitive TiO & CrH bands. We have identified
two plausible causes of variability: surface features rotating into- and
out-of-view and so modulating the light curve at the rotation period; or,
elliposidal variability caused by an orbiting companion. In the first scenario,
we combine the observed vsin(i) of Kelu-1 and standard model radius to
determine that the axis of rotation is inclined at 65+/-12 degrees to the line
of sight.Comment: 7 pages, 9 figures. Accepted for publication in MNRA
Global environmental effects of impact-generated aerosols: Results from a general circulation model
Cooling and darkening at Earth's surface are expected to result from the interception of sunlight by the high altitude worldwide dust cloud generated by impact of a large asteroid or comet, according to the one-dimensional radioactive-convective atmospheric model (RCM) of Pollack et al. An analogous three-dimensional general circulation model (GCM) simulation obtains the same basic result as the RCM but there are important differences in detail. In the GCM simulation the heat capacity of the oceans, not included in the RCM, substantially mitigates land surface cooling. On the other hand, the GCM's low heat capacity surface allows surface temperatures to drop much more rapidly than reported by Pollack et al. These two differences between RCM and GCM simulations were noted previously in studies of nuclear winter; GCM results for comet/asteroid winter, however, are much more severe than for nuclear winter because the assumed aerosol amount is large enough to intercept all sunlight falling on Earth. In the simulation the global average of land surface temperature drops to the freezing point in just 4.5 days, one-tenth the time required in the Pollack et al. simulation. In addition to the standard case of Pollack et al., which represents the collision of a 10-km diameter asteroid with Earth, additional scenarios are considered ranging from the statistically more frequent impacts of smaller asteroids to the collision of Halley's comet with Earth. In the latter case the kinetic energy of impact is extremely large due to the head-on collision resulting from Halley's retrograde orbit
A study of fiber volume fraction effects in notched unidirectional SCS-6/Ti-15V-3Cr-3Al-3Sn composite
Notched unidirectional SCS-6/Ti-15-3 composite of three different fiber volume fractions (vf = 0.15, 0.37, and 0.41) was investigated for various room temperature microstructural and material properties including: fatigue crack initiation, fatigue crack growth, and fracture toughness. While the matrix hardness is similar for all fiber volume fractions, the fiber/matrix interfacial shear strength and matrix residual stress increases with fiber volume fraction. The composite fatigue crack initiation stress is shown to be matrix controlled and occurs when the net maximum matrix stress approaches the endurance limit stress of the matrix. A model is presented which includes residual stresses and presents the composite initiation stress as a function of fiber volume fraction. This model predicts a maximum composite initiation stress at vf approximately 0.15 which agrees with the experimental data. The applied composite stress levels were increased as necessary for continued crack growth. The applied Delta(K) values at crack arrest increase with fiber volume fraction by an amount better approximated using an energy based formulation rather than when scaled linear with modulus. After crack arrest, the crack growth rate exponents for vf37 and vf41 were much lower and toughness much higher, when compared to the unreinforced matrix, because of the bridged region which parades with the propagating fatigue crack. However, the vf15 material exhibited a higher crack growth rate exponent and lower toughness than the unreinforced matrix because once the bridged fibers nearest the crack mouth broke, the stress redistribution broke all bridged fibers, leaving an unbridged crack. Degraded, unbridged behavior is modeled using the residual stress state in the matrix ahead of the crack tip. Plastic zone sizes were directly measured using a metallographic technique and allow prediction of an effective matrix stress intensity which agrees with the fiber pressure model if residual stresses are considered. The sophisticated macro/micro finite element models of the 0.15 and 0.37 fiber volume fractions presented show good agreement with experimental data and the fiber pressure model when an estimated effective fiber/matrix debond length is used
Nothing to hide: An X-ray survey for young stellar objects in the Pipe Nebula
We have previously analyzed sensitive mid-infrared observations to establish
that the Pipe Nebula has a very low star-formation efficiency. That study
focused on YSOs with excess infrared emission (i.e, protostars and pre-main
sequence stars with disks), however, and could have missed a population of more
evolved pre-main sequence stars or Class III objects (i.e., young stars with
dissipated disks that no longer show excess infrared emission). Evolved
pre-main sequence stars are X-ray bright, so we have used ROSAT All-Sky Survey
data to search for diskless pre-main sequence stars throughout the Pipe Nebula.
We have also analyzed archival XMM-Newton observations of three prominent areas
within the Pipe: Barnard 59, containing a known cluster of young stellar
objects; Barnard 68, a dense core that has yet to form stars; and the Pipe
molecular ring, a high-extinction region in the bowl of the Pipe. We
additionally characterize the X-ray properties of YSOs in Barnard 59. The ROSAT
and XMM-Newton data provide no indication of a significant population of more
evolved pre-main sequence stars within the Pipe, reinforcing our previous
measurement of the Pipe's very low star formation efficiency.Comment: Accepted for publication in Ap
Risk Perception of Cigarette and E-cigarette use during Pregnancy: A Qualitative Postpartum Perspective
Aim: The aim of this exploratory qualitative analysis is to assess the perceptions of risks of cigarette and e-cigarette use during pregnancy. Background: An important public health aim is a reduction of smoking at time of delivery (SATOD) from 10.6% to less than 6% by 2022 in the United Kingdom (UK). In order to successfully meet this target, we need to have a better understanding of the perceived risks associated with cigarette smoking. Additionally, the use of e-cigarettes is increasing in the general population, with pregnant women being supported to use such products if it helps them remain smoke free. However, in contrast to cigarette smoking, there is little definitive research assessing the safety of e-cigarette use during pregnancy, with most information disregarding the health of the growing fetus. E-cigarettes are of special interest, given they are an unlicensed product for use during pregnancy, yet women are being supported to use them as a method of harm reduction. A better understanding of perceived risks is essential. Method: Fourteen interviews were conducted one month postpartum with women who smoked during pregnancy and continued to smoke after the birth. Thematic analysis was conducted. Suzanne Froggatt, Nadja Reissland, Judith Covey 2 Findings: Two themes emerged for cigarette smoking; health and justifications. Six themes were identified for e-cigarette use; the unknown, experience, comparison to cigarettes, the product, advice and healthier option. A range of subthemes are discussed. Conclusion: Women provided a range of justifications for continuing to smoke during pregnancy. Women felt e-cigarettes were a riskier option than continuing to smoke
Vsini-s for late-type stars from spectral synthesis in K-band region
We analyse medium-resolution spectra (R\sim 18000) of 19 late type dwarfs in
order to determine vsini-s using synthetic rather than observational template
spectra. For this purpose observational data around 2.2 m of stars with
spectral classes from G8V to M9.5V were modelled.
We find that the Na I (2.2062 and 2.2090 m) and CO 2-0 band
features are modelled well enough to use for vsini determination without the
need for a suitable observational template spectra. Within the limit of the
resolution of our spectra, we use synthetic spectra templates to derive vsini
values consistent with those derived in the optical regime using observed
templates. We quantify the errors in our vsini determination due to incorrect
choice of model parameters \Teff, log , , [Fe/H] or FWHM and
show that they are typically less than 10 per cent. We note that the spectral
resolution of our data(\sim 16 km/s) limited this study to relatively fast
rotators and that resolutions of 60000 will required to access most late-type
dwarfs.Comment: 8 pages, 4 figures, 3 tables, accepted to the MNRA
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