94 research outputs found
A Comparison of Attitude Change in Senior Citizen and College Age Subjects
The present study was designed to examine the validity of generally held assumptions of decreased attitudinal flexibility in the aged. A preliminary study preceded the formal study and identified a target attitude, sources of varying credibility, and evaluated self-esteem as a possible confounding variable. Subsequently 40 college age and 40 senior citizen subjects\u27 attitude toward the Equal Rights Amendment were measured by a paper and pencil survey. Two weeks later an anti- E.R.A. attitude change message, attributed to sources of varying age and credibility, was presented and its impact measured by a posttest survey. Follow-up measures were taken three weeks later.
An analysis of covariance yielded a significant subject age effect at the posttest with greater attitude change exhibited by the senior citizens. Neither source age nor source credibility main effects reached significance and there were no significant interactions. On the follow-up measure there were no significant main effects or interactions, though subject age approached significance. The results were interpreted as being contrary to assumptions of increased rigidity in the elderly and not supportive of the decrement model of aging. Methodological difficulties were discussed with respect to the results found and further research was recommended
Attraction of a Senior Citizen to a Hypothetical Stranger as a Function of the Stranger\u27s Age, Sex, and Attitude Similarity
The present study was designed to examine the variables which affect attraction in a senior citizen population. In particular, variables which have been shown to affect attraction in younger persons were examined as to their relevancy to older subjects. It was predicted that a strangerâs age, sex, and proportion of similar attitudes would have a significant effect on a senior citizen\u27s attraction rating of the stranger.
A strangerâs age, sex, and proportion of similar attitudes were varied according to a 3 (proportion of similar attitudes) X 3 (age of stranger) X 2 (sex of stranger) factorial design. Male and female senior-citizen subjects responded to attitude surveys representing the age, sex, and attitudes of the hypothetical stranger. The subjectâs response was completion of a rating scale of his attraction toward the stranger based on the information in the attitude survey.
It was found that only the proportion of similar attitudes had a significant effect on a senior citizen\u27s attraction rating of a stranger. Age and sex of the stranger had no significant effect and none of the interactions among the variables reached significance. It was also found th^t the sex of the subject had no effect on his attraction rating of the stranger.
Further research was suggested to study the use of paper and pencil techniques with older subjects
Ueber eine dem Bilde der cerebrospinalen grauen Degeneration Ă€hnliche Erkrankung des centralen Nervensystems ohne anatomischen Befund, nebst einigen Bemerkungen ĂŒber paradoxe Contraction
Correction to: Bone defect reconstruction with a novel biomaterial containing calcium phosphate and aluminum oxide reinforcement
Stellar Populations at the Center of IC 1613
We have observed the center of the Local Group dwarf irregular galaxy IC 1613
with WFPC2 aboard the Hubble Space Telescope in the F439W, F555W, and F814W
filters. We find a dominant old stellar population (aged ~7 Gyr), identifiable
by the strong red giant branch (RGB) and red clump populations. From the (V-I)
color of the RGB, we estimate a mean metallicity of the intermediate-age
stellar population [Fe/H] = -1.38 +/- 0.31. We confirm a distance of 715 +/- 40
kpc using the I-magnitude of the RGB tip. The main-sequence luminosity function
down to I ~25 provides evidence for a roughly constant SFR of approximately
0.00035 solar masses per year across the WFPC2 field of view (0.22 square kpc)
during the past 250-350 Myr. Structure in the blue loop luminosity function
implies that the SFR was ~50% higher 400-900 Myr ago than today. The mean heavy
element abundance of these young stars is 1/10th solar. The best explanation
for a red spur on the main-sequence at I = 24.7 is the blue horizontal branch
component of a very old stellar population at the center of IC 1613. We have
also imaged a broader area of IC 1613 using the 3.5-meter WIYN telescope under
excellent seeing conditions. The AGB-star luminosity function is consistent
with a period of continuous star formation over at least the age range 2-10
Gyr. We present an approximate age-metallicity relation for IC 1613, which
appears similar to that of the Small Magellanic Cloud. We compare the Hess
diagram of IC 1613 to similar data for three other Local Group dwarf galaxies,
and find that it most closely resembles the nearby, transition-type dwarf
galaxy Pegasus (DDO 216).Comment: To appear in the September 1999 Astronomical Journal. LaTeX, uses
AASTeX v4.0, emulateapj style file, 19 pages, 12 postscript figures, 2
tables. 5 of the figures available separately via the WW
Hubble Space Telescope Observations of the Draco Dwarf Spheroidal
We present an F606W-F814W color-magnitude diagram for the Draco dwarf
spheroidal galaxy based on Hubble Space Telescope WFPC2 images. The luminosity
function is well-sampled to 3 magnitudes below the turn-off. We see no evidence
for multiple turnoffs and conclude that, at least over the field of the view of
the WFPC2, star formation was primarily single-epoch. If the observed number of
blue stragglers is due to extended star formation, then roughly 6% (upper
limit) of the stars could be half as old as the bulk of the galaxy. The color
difference between the red giant branch and the turnoff is consistent with an
old population and is very similar to that observed in the old, metal-poor
Galactic globular clusters M68 and M92. Despite its red horizontal branch,
Draco appears to be older than M68 and M92 by 1.6 +/- 2.5 Gyrs, lending support
to the argument that the ``second parameter'' which governs horizontal branch
morphology must be something other than age. Draco's observed luminosity
function is very similar to that of M68, and the derived initial mass function
is consistent with that of the solar neighborhood.Comment: 16 pages, AASTeX, 9 postscript figures, figures 1 and 2 available at
ftp://bb3.jpl.nasa.gov/pub/draco/. Accepted for publication in the
Astronomical Journa
Growth factor-mediated augmentation of long bones: evaluation of a BMP-7 loaded thermoresponsive hydrogel in a murine femoral intramedullary injection model
Background
Due to our aging population, an increase in proximal femur fractures can be expected, which is associated with impaired activities of daily living and a high risk of mortality. These patients are also at a high risk to suffer a secondary osteoporosis-related fracture on the contralateral hip. In this context, growth factors could open the field for regenerative approaches, as it is known that, i.e., the growth factor BMP-7 (bone morphogenetic protein 7) is a potent stimulator of osteogenesis. Local prophylactic augmentation of the proximal femur with a BMP-7 loaded thermoresponsive hydrogel during index surgery of an osteoporotic fracture could be suitable to reduce the risk of further osteoporosis-associated secondary fractures. The present study therefore aims to test the hypothesis if a BMP-7 augmented hydrogel is an applicable carrier for the augmentation of non-fractured proximal femurs. Furthermore, it needs to be shown that the minimally invasive injection of a hydrogel into the mouse femur is technically feasible.
Methods
In this study, male C57BL/6 mice (nâ=â36) received a unilateral femoral intramedullary injection of either 100âÎŒl saline, 100âÎŒl 1,4 Butan-Diisocyanat (BDI)-hydrogel, or 100âÎŒl hydrogel loaded with 1âÎŒg of bone morphogenetic protein 7. Mice were sacrificed 4 and 12âweeks later. The femora were submitted to high-resolution X-ray tomography and subsequent histological examination.
Results
Analysis of normalized CtBMD (Cortical bone mineral density) as obtained by X-ray micro-computed tomography analysis revealed significant differences depending on the duration of treatment (4 vs 12âweeks; pâ<â0.05). Furthermore, within different anatomically defined regions of interest, significant associations between normalized TbN (trabecular number) and BV/TV (percent bone volume) were noted. Histology indicated no signs of inflammation and no signs of necrosis and there were no cartilage damages, no new bone formations, or new cartilage tissues, while BMP-7 was readily detectable in all of the samples.
Conclusions
In conclusion, the murine femoral intramedullary injection model appears to be feasible and worth to be used in subsequent studies that are directed to examine the therapeutic potential of BMP-7 loaded BDI-hydrogel. Although we were unable to detect any significant osseous effects arising from the mode or duration of treatment in the present trial, the effect of different concentrations and duration of treatment in an osteoporotic model appears of interest for further experiments to reach translation into clinic and open new strategies of growth factor-mediated augmentation
Stellar Populations in Three Outer Fields of the LMC
We present HST photometry for three fields in the outer disk of the LMC
extending approximately four magnitudes below the faintest main sequence
turnoff. We cannot detect any strongly significant differences in the stellar
populations of the three fields based on the morphologies of the
color-magnitude diagrams, the luminosity functions, and the relative numbers of
stars in different evolutionary stages. Our observations therefore suggest
similar star formation histories in these regions, although some variations are
certainly allowed. The fields are located in two regions of the LMC: one is in
the north-east field and two are located in the north-west. Under the
assumption of a common star formation history, we combine the three fields with
ground-based data at the same location as one of the fields to improve
statistics for the brightest stars. We compare this stellar population with
those predicted from several simple star formation histories suggested in the
literature, using a combination of the R-method of Bertelli et al (1992) and
comparisons with the observed luminosity function. The only model which we
consider that is not rejected by the observations is one in which the star
formation rate is roughly constant for most of the LMC's history and then
increases by a factor of three about 2 Gyr ago. Such a model has roughly equal
numbers of stars older and younger than 4 Gyr, and thus is not dominated by
young stars. This star formation history, combined with a closed box chemical
evolution model, is consistent with observations that the metallicity of the
LMC has doubled in the past 2 Gyr.Comment: 30 pages, includes 10 postscript figures. Figure 1 avaiable at
ftp://charon.nmsu.edu/pub/mgeha/LMC. Accepted for publication in Astronomical
Journa
Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source
Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a wellcharacterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 mu m diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 angstrom ngstrom were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.11Ysciescopu
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