8,439 research outputs found
Fathering practices in twenty-six intact families and the implications for child contact
The nature of the contribution that fathers make to families is the subject of intense debate by both academics and policymakers. Contact between non-resident fathers and their children has been promoted by government and the courts, but remains difficult to achieve. This paper reports on interview data collected from fathers, mothers and their adolescent children in intact families on the perceptions of fathering practices and the factors that influence them. In addition, the nature and extent of fathers’ involvement with their children is explored in relation to the problem of ‘boundary setting’.
While the traditional, rather distant, breadwinning father has disappeared, there is no evidence from this study of a shift towards the kind of father who takes equal day-to-day responsibility for his children. Rather, the changes in the nature of fathers’ involvement with their children are more subtle, relying to a large extent on an appreciation of the importance of ‘passive care’ and of mediation by mothers. We suggest that these findings have important implications for what might be expected by and of fathers when relationships break-up, and for the development of policies to encourage father involvement
Solar energy conversion through the interaction of plasmons with tunnel junctions. Part A: Solar cell analysis. Part B: Photoconductor analysis
A solar cell utilizing guided optical waves and tunnel junctions was analyzed to determine its feasibility. From this analysis, it appears that the limits imposed upon conventional multiple cell systems also limit this solar cell. Due to this limitation, it appears that the relative simplicity of the conventional multiple cell systems over the solar cell make the conventional multiple cell systems the more promising candidate for improvement. It was discovered that some superlattice structures studied could be incorporated into an infrared photodetector. This photoconductor appears to be promising as a high speed, sensitive (high D sup star sub BLIP) detector in the wavelength range from 15 to over 100 micrometers
The Second Galex Ultraviolet Variability (GUVV-2) Catalog
We present the second Galaxy Evolution Explorer (GALEX) Ultraviolet
Variability (GUVV-2) Catalog that contains information on 410 newly discovered
time-variable sources gained through simultaneous near (NUV 1750-2750A) and far
(FUV 1350-1750A) ultraviolet photometric observations. Source variability was
determined by comparing the NUV and/or FUV fluxes derived from orbital
exposures recorded during a series of multiple observational visits to 169
GALEX fields on the sky. These sources, which were contained within a sky-area
of 161 square deg, varied on average by amplitudes of NUV = 0.6 mag and FUV =
0.9 mag during these observations. Of the 114 variable sources in the catalog
with previously known identifications, 67 can be categorized as being active
galaxies (QSO's, Seyfert 1 or BL Lac objects). The next largest groups of UV
variables are RR Lyrae stars, X-ray sources and novae.
By using a combination of UV and visible color-color plots we have been able
to tentatively identify 36 possible RR Lyrae and/or Delta Scuti type stars, as
well as 35 probable AGN's, many of which may be previously unidentified QSO's
or blazars. Finally, we show data for 3 particular variable objects: the
contact binary system of SDSS J141818.97+525006.7, the eclipsing dwarf nova
system of IY UMa and the highly variable unidentified source SDSS
J104325.06+563258.1.Comment: Astronomical Journal accepte
GALEX ultraviolet observations of stellar variability in the Hyades and Pleiades clusters
We present GALEX near ultraviolet (NUV:1750 - 2750A) and far ultraviolet
(FUV: 1350 - 1750A) imaging observations of two 1.2 degree diameter fields in
the Hyades and Pleiades open clusters in order to detect possible UV
variability of the member stars. We have performed a detailed software search
for short-term UV flux variability during these observations of the approx 400
sources detected in each of the Hyades and Pleiades fields to identify
flare-like (dMe) stellar objects. This search resulted in the detection of 16
UV variable sources, of which 13 can be directly associated with probable
M-type stars. The other UV sources are G-type stars and one newly discovered RR
Lyrae star, USNOB1.0 1069-0046050, of period 0.624 day and distance 4.5-7.0
kpc. Light curves of photon flux versus time are shown for 7 flare events
recorded on six probable dMe stars. UV energies for these flares span the range
2E27 to 5E29 erg, with a corresponding NUV variability change of 1.82 mag. Only
one of these flare events (on the star Cl* Melotte 25 LH129) can definitely be
associated with an origin on a member the Hyades cluster itself. Finally, many
of our M-type candidates show long periods of enhanced UV activity but without
the associated rapid increase in flux that is normally associated with a flare
event. However, the total UV energy output during such periods of increased
activity is greater than that of many short-term UV flares. These intervals of
enhanced low-level UV activity concur with the idea that, even in quiescence,
the UV emission from dMe stars may be related to a superposition of many small
flare events possessing a wide range of energies.Comment: PASP Submitte
Development of sustainable biodegradable lignocellulosic hemp fiber/polycaprolactone biocomposites for light weight applications
Biocomposites with poly(ε-caprolactone) (PCL) as matrix and lignocellulosic hemp fiber with varying average aspect ratios (19, 26, 30 and 38) as reinforcement were prepared using twin extrusion process. The influence of fiber aspect ratio on the water absorption behavior and mechanical properties are investigated. The percentage of moisture uptake increased with the aspect ratio, following Fickian behavior. The hemp fiber/PCL biocomposites showed enhanced properties (tensile, flexural and low-velocity impact). The biocomposite with 26 aspect ratio showed the optimal properties, with flexural strength and modulus of 169% and 285% respectively, higher than those of neat PCL. However, a clear reduction on the mechanical properties was observed for water-immersed samples, with reduction in tensile and flexural moduli for the aspect ratio of 26 by 90% and 62%, respectively than those of dry samples. Summarily, the optimal sample provides an eco-friendly alternative to conventional, petroleum-based and non-renewable composites for various applications.Peer reviewedFinal Accepted Versio
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