276 research outputs found
The Social Basis of Trust in Government
The relationship between the attitude of trust in government and socio-economic characteristics of the respondents is examined . Survey research data permit an empirical assessment of political trust as the dependent variable . The concept of political trust is operationalized through an interview question, and the independent variable is given empirical reference by the use of demographic data. The evidence suggests that a low level of political trust is pervasive throughout all the segments of the American society and that trust in government is not highly correlated with any social group
Education As A Strategy in Foreign Policy of the United States
The role of international education as an element in the foreign policy strategy of the United States is examined from the end of World War II until the late sixties. It is hypothesized that education was used as a convenient device during the period of the Cold War for conducting international relations when the battle for men\u27s minds was being fought by the superpowers. Data presented indicates that with the intensification of the Cold War, a greater interest was expressed in international educational projects. As an instrument of the United States foreign policy, education was conceived as a convenient format for the achievement of both long range and short term national goals, through the development of a common framework for elite socialization and the articulation of a positive image of the United States around the world
Imaging the Radio Photospheres of Mira Variables
We have used the VLA at 43 GHz to image the radio continuum emission from o
Ceti, R Leo, and W Hya and to precisely locate their SiO maser emission with
respect to the star. The radio continuum emission region for all three stars
has a diameter close to 5.6 AU. These diameters are similar to those measured
at infrared wavelengths in bands containing strong molecular opacity and about
twice those measured in line-free regions of the infrared spectrum. Thus, the
radio photosphere and the infrared molecular layer appear to be coextensive.
The 43 GHz continuum emission is consistent with temperatures near 1600 K and
opacity from H-minus free-free interactions. While the continuum image of o
Ceti appears nearly circular, both R Leo and W Hya display significant
elongations. The SiO masers for all three stars show partial rings with
diameters close to 8 AU.Comment: 14 pages; 3 figure
On the Formation of Multiple-Shells Around Asymptotic Giant Branch Stars
Two types of models for the formation of semi-periodic concentric multiple
shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary
nebulae are compared against observations. Models that attribute the M-shells
to processes in an extended wind acceleration zone around AGB stars result in
an optically thick acceleration zone, which reduces the acceleration efficiency
in outer parts of the extended acceleration zone. This makes such models an
unlikely explanation for the formation of M-shells. Models which attribute the
M-shell to semi-periodic variation in one or more stellar properties are most
compatible with observations. The only stellar variation models on time scales
of 50-1500 years that have been suggested are based on an assumed solar-like
magnetic cycle. Although ad-hoc, the magnetic cycle assumption fits naturally
into the increasingly popular view that magnetic activity plays a role in
shaping the wind from upper AGB stars.Comment: 8 pages, Submitted to Ap
Resolving the hot dust around HD69830 and eta Corvi with MIDI and VISIR
Most of the known debris discs exhibit cool dust in regions analogous to the
Edgeworth-Kuiper Belt. However, a rare subset show hot excess from within a few
AU, which is often inferred to be transient. We examine 2 such sources to place
limits on their location to help distinguish between different interpretations
for their origin. We use MIDI on the VLTI to observe the debris discs around
eta Corvi and HD69830 using baseline lengths from 44-130m. New VISIR
observations of HD69830 at 18.7um are also presented. These observations are
compared with disc models to place limits on disc size. The visibility
functions measured with MIDI for both sources show significant variation with
wavelength across 8-13um in a manner consistent with the disc flux being well
resolved, notably with a dip at 10-11.5um due to the silicate emission feature.
The average ratio of visibilities measured between 10-11.5um and 8-9um is
0.934+/-0.015 for HD69830 and 0.880+/-0.013 for eta Corvi over the 4 baselines
for each source, a departure of 4 and 9sigma from that expected if the discs
were unresolved. HD69830 is unresolved by VISIR at 18.7um. The combined limits
from MIDI and 8m imaging constrain the warm dust to lie within 0.05-2.4AU for
HD69830 and 0.16-2.98AU for eta Corvi. These results represent the first
resolution in the mid-IR of dust around main sequence stars. The constraints
placed on the location of the dust are consistent with radii predicted by SED
modelling. Tentative evidence for a common position angle for the dust at 1.7AU
with that at 150AU around eta Corvi, which might be expected if the hot dust is
fed from the outer disc, demonstrates the potential of this technique for
constraining the origin of the dust and more generally for the study of dust in
the terrestrial regions of main sequence stars.Comment: Accepted for publication in Astronomy and Astrophysic
Maternal Folate Status and Risk Factors for Autism Spectrum Disorders
Autism spectrum disorders (ASD) are thought to be influenced by environmental, genetic, and maternal factors, including potential links to periconceptional folic acid. This quantitative case-control study, guided by the life course theory, explored the association of maternal risk factors (age, race, education, income, folate status, gestational diabetes, gestational hypertension, and MTHFR mutation) on the precipitation of ASD in offspring. The sample comprised 96 mothers of children with ASD and 143 mothers of children without ASD. Logistic regression analysis indicated no significant association between maternal folate status and ASD (OR = 1.00, 95% CI [1.000, 0.001], p = .755). Mothers with higher education were significantly less likely to have offspring with ASD than mothers with a high school diploma, GED, or less (OR = 0.251, 95% CI [0.103, 0.61], p = .002). Univariate analysis found the presence of gestational diabetes to be significantly associated (OR = 5.776, 95% CI [2.357, 14.156], p = \u3c .001) and preeclampsia to be insignificantly associated (OR = 1.564, 95% CI [0.705, 3.469], p = .272) with ASD. However, an inverse relationship was observed between gestational diabetes and ASD in the final model. Further research is recommended to explore the relationship between ASD and maternal conditions, namely gestational diabetes and preeclampsia. These findings underscore the need for comprehensive prenatal care to promote optimal supplementation, nutrition, and strategies targeting modifiable risk factors in ASD risk during pregnancy. Within this context, researchers can better understand ASD etiology, develop targeted interventions, and contribute to more effective prevention efforts
Multi-wavelength visibility measurements of the red giant R Doradus
We present visibility measurements of the nearby Mira-like star R Doradus
taken over a wide range of wavelengths (650--990 nm). The observations were
made using MAPPIT (Masked APerture-Plane Interference Telescope), an
interferometer operating at the 3.9-m Anglo-Australian Telescope. We used a
slit to mask the telescope aperture and prism to disperse the interference
pattern in wavelength. We observed in R Dor strong decreases in visibility
within the TiO absorption bands. The results are in general agreement with
theory but differ in detail, suggesting that further work is needed to refine
the theoretical models.Comment: 8 pages; SPIE Conf. 4006 "Interferometry in Optical Astronomy
Amphiphilic graphene oxide stabilisation of hexagonal BN and MoS2 sheets
Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.A simple and scalable method has been developed for directly forming water-dispersible van der Waals solids involving mixing aqueous solution of graphene oxide (GO) with hexagonal boron nitride (BN) or molybdenum disulphide (MoS2) in N-methylpyrrolidone. The GO acts as an amphiphile in stabilising the colloidal solutions of the heterolaminar material in water
High fidelity imaging of geosynchronous satellites with the MROI
Interferometry currently provides the only practicable way to image satellites in Geosynchronous Earth Orbit (GEO) with sub-meter spatial resolution. The Magdalena Ridge Observatory Interferometer (MROI) is being funded by the US Air Force Research Laboratory to demonstrate the 9.5 magnitude sensitivity (at 2.2 µm wavelength) and baseline-bootstrapping capability that will be needed to realize a useful turn-key GEO imaging capability. This program will utilize the central three telescopes of the MROI and will aim to validate routine acquisition of fringe data on faint well-resolved targets. In parallel with this effort, the University of Cambridge are investigating the spatial resolution and imaging fidelity that can be achieved with different numbers of array elements. We present preliminary simulations of snapshot GEO satellite imaging with the MROI. Our results indicate that faithful imaging of the main satellite components can be obtained with as few as 7 unit telescopes, and that increasing the number of telescopes to 10 improves the effective spatial resolution from 0.75 meter to 0.5 meter and enables imaging of more complex targets.This is the author accepted manuscript. The final version is available from SPIE via http://dx.doi.org/10.1117/12.223247
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