1,086 research outputs found
The Association Between Health Literacy and Diet Adherence Among Primary Care Patients with Hypertension
This study examines the association between health literacy and adherence to low-salt diet practices among individuals with hypertension. Health literacy is the ability of individuals to understand and utilize health information. We surveyed 238 patients with hypertension from a primary care clinic in Charlotte, NC. We assessed health literacy and self-reported low-salt diet. Logistic regression was used to model the relationship between health literacy and low-salt diet adherence. Respondents were primarily female (67.3%) and black (80%). Black Americans were less likely to have adequate health literacy as compared to white Americans (21.8% vs. 55.8%). The study found no association between adequate health literacy and adherence to a low-salt diet (OR = 1.06, 95% CI: 0.36-3.10) after adjusting for confounders. This study addresses the conflicting findings for health literacy in two related areas: chronic illness self-care, and nutrition/diet skills. Additional research is warranted among black Americans given their increased risk of hypertension, low rates of diet adherence and previous findings of positive associations between health literacy and nutrition skills
Representational precision in visual cortex reveals outcome encoding and reward modulation during action preparation
According to ideomotor theory, goal-directed action involves the active perceptual anticipation of actions and their associated effects. We used multivariate analysis of fMRI data to test if preparation of an action promotes precision in the perceptual representation of the action. In addition, we tested how reward magnitude modulates this effect. Finally, we examined how expectation and uncertainty impact neural precision in the motor cortex. In line with our predictions, preparation of a hand or face action increased the precision of neural activation patterns in the extrastriate body area (EBA) and fusiform face area (FFA), respectively. The size of this effect of anticipation predicted individuals\u27 efficiency at performing the prepared action. In addition, increasing reward magnitude increased the precision of perceptual representations in both EBA and FFA although this effect was limited to the group of participants that learned to associate face actions with high reward. Surprisingly, examination of representations in the hand motor cortex and face motor cortex yielded effects in the opposite direction. Our findings demonstrate that the precision of representations in visual and motor areas provides an important neural signature of the sensorimotor representations involved in goal-directed action
Rest-frame optical continua of L ~ L*, z>3 quasars: probing the faint end of the high z quasar luminosity function
Near-IR photometry for 20 radio-loud z>3 quasars, 16 of which are radio-
selected, are presented. These data sample the rest-frame optical/UV continuum,
which is commonly interpreted as emission from an accretion disk. In a previous
study, we compared the rest-frame optical/UV continuum shapes of 15 optically
bright (V3 quasars with those of 27 low redshift (z~0.1) ones that
were matched to the high redshift sample in evolved luminosity (i.e. having
luminosities ranging from 1-7 times the characteristic luminosity, L*, where
L*~(1+z)^{~3}) to look for signs of evolution in the central engines. We found
the continuum shapes at z~0.1 and z>3 similar, consistent with no significant
change in the ratio mdot/M, where mdot is the accretion rate with respect to
the Eddington rate and M is the black hole mass. This study expands our earlier
high redshift sample to lower luminosity, away from extreme objects and towards
a luminosity overlap with lower redshift samples. The distribution of
rest-frame optical/UV continuum shapes for this fainter sample is broader,
extending further to the red than that of the brighter z>3 one. Three quasars
from this fainter sample, two radio-selected and one optically-selected, have
optical continuum slopes alpha<-1 (F_{nu}~nu^{alpha}). The optically-selected
one, LBQS0056+0125, appears to be reddened by dust along the line of sight or
in the host galaxy, whereas the radio-selected ones, PKS2215+02 and
TXS2358+189, could derive their red continua from the contribution of a
relatively strong synchrotron component to the rest-frame optical. These
objects may represent a bridge to a population of very red high redshift
quasars to which ongoing or future near-IR, optical and deep X-ray surveys will
be sensitive.Comment: 16 pages, 6 figures; accepted for publication in MNRA
Neural correlates of sexual cue reactivity in individuals with and without compulsive sexual behaviours
Although compulsive sexual behaviour (CSB) has been conceptualized as a "behavioural" addiction and common or overlapping neural circuits may govern the processing of natural and drug rewards, little is known regarding the responses to sexually explicit materials in individuals with and without CSB. Here, the processing of cues of varying sexual content was assessed in individuals with and without CSB, focusing on neural regions identified in prior studies of drug-cue reactivity. 19 CSB subjects and 19 healthy volunteers were assessed using functional MRI comparing sexually explicit videos with non-sexual exciting videos. Ratings of sexual desire and liking were obtained. Relative to healthy volunteers, CSB subjects had greater desire but similar liking scores in response to the sexually explicit videos. Exposure to sexually explicit cues in CSB compared to non-CSB subjects was associated with activation of the dorsal anterior cingulate, ventral striatum and amygdala. Functional connectivity of the dorsal anterior cingulate-ventral striatum-amygdala network was associated with subjective sexual desire (but not liking) to a greater degree in CSB relative to non-CSB subjects. The dissociation between desire or wanting and liking is consistent with theories of incentive motivation underlying CSB as in drug addictions. Neural differences in the processing of sexual-cue reactivity were identified in CSB subjects in regions previously implicated in drug-cue reactivity studies. The greater engagement of corticostriatal limbic circuitry in CSB following exposure to sexual cues suggests neural mechanisms underlying CSB and potential biological targets for interventions
High-resolution polarimetry of Parsamian 21: revealing the structure of an edge-on FU Ori disc
We present the first high spatial resolution near-infrared direct and
polarimetric observations of Parsamian 21, obtained with the VLT/NACO
instrument. We complemented these measurements with archival infrared
observations, such as HST/WFPC2 imaging, HST/NICMOS polarimetry, Spitzer IRAC
and MIPS photometry, Spitzer IRS spectroscopy as well as ISO photometry. Our
main conclusions are the following: (1) we argue that Parsamian 21 is probably
an FU Orionis-type object; (2) Parsamian 21 is not associated with any rich
cluster of young stars; (3) our measurements reveal a circumstellar envelope, a
polar cavity and an edge-on disc; the disc seems to be geometrically flat and
extends from approximately 48 to 360 AU from the star; (4) the SED can be
reproduced with a simple model of a circumstellar disc and an envelope; (5)
within the framework of an evolutionary sequence of FUors proposed by Green et
al. (2006) and Quanz et al. (2007), Parsamian 21 can be classified as an
intermediate-aged object.Comment: Accepted for publication in the MNRAS. 16 pages, 18 figures and 5
table
Limits of Abductivism About Logic
I argue against abductivism about logic, which is the view that rational theory choice in logic happens by abduction. Abduction cannot serve as a neutral arbiter in many foundational disputes in logic because, in order to use abduction, one must first identify the relevant data. Which data one deems relevant depends on what I call one's conception of logic. One's conception of logic is, however, not independent of one's views regarding many of the foundational disputes that one may hope to solve by abduction
Only the Lonely: H I Imaging of Void Galaxies
Void galaxies, residing within the deepest underdensities of the Cosmic Web,
present an ideal population for the study of galaxy formation and evolution in
an environment undisturbed by the complex processes modifying galaxies in
clusters and groups, as well as provide an observational test for theories of
cosmological structure formation. We have completed a pilot survey for the HI
imaging aspects of a new Void Galaxy Survey (VGS), imaging 15 void galaxies in
HI in local (d < 100 Mpc) voids. HI masses range from 3.5 x 10^8 to 3.8 x 10^9
M_sun, with one nondetection with an upper limit of 2.1 x 10^8 M_sun. Our
galaxies were selected using a structural and geometric technique to produce a
sample that is purely environmentally selected and uniformly represents the
void galaxy population. In addition, we use a powerful new backend of the
Westerbork Synthesis Radio Telescope that allows us to probe a large volume
around each targeted galaxy, simultaneously providing an environmentally
constrained sample of fore- and background control sample of galaxies while
still resolving individual galaxy kinematics and detecting faint companions in
HI. This small sample makes up a surprisingly interesting collection of
perturbed and interacting galaxies, all with small stellar disks. Four galaxies
have significantly perturbed HI disks, five have previously unidentified
companions at distances ranging from 50 to 200 kpc, two are in interacting
systems, and one was found to have a polar HI disk. Our initial findings
suggest void galaxies are a gas-rich, dynamic population which present evidence
of ongoing gas accretion, major and minor interactions, and filamentary
alignment despite the surrounding underdense environment.Comment: 53 pages, 18 figures, accepted for publication in AJ. High resolution
available at http://www.astro.columbia.edu/~keejo/kreckel2010.pd
Simulated Optimisation of Disordered Structures with negative Poisson’s ratios
Copyright © 2009 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Mechanics of Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanics of Materials, Vol. 41 Issue 8 (2009). DOI: 10.1016/j.mechmat.2009.04.008Two-dimensional regular theoretical units that give a negative Poisson’s ratio (NPR) are well documented and well understood. Predicted mechanical properties resulting from these models are reasonably accurate in two dimensions but fall down when used for heterogeneous real-world materials. Manufacturing processes are seldom perfect and some measure of heterogeneity is therefore required to account for the deviations from the regular unit cells in this real-life situation. Analysis of heterogeneous materials in three dimensions is a formidable problem; we must first understand heterogeneity in two dimensions. This paper approaches the problem of finding a link between heterogeneous networks and its material properties from a new angle. Existing optimisation tools are used to create random two-dimensional topologies that display NPR, and the disorder in the structure and its relationship with NPR is investigated
The faint young Sun problem
For more than four decades, scientists have been trying to find an answer to
one of the most fundamental questions in paleoclimatology, the `faint young Sun
problem'. For the early Earth, models of stellar evolution predict a solar
energy input to the climate system which is about 25% lower than today. This
would result in a completely frozen world over the first two billion years in
the history of our planet, if all other parameters controlling Earth's climate
had been the same. Yet there is ample evidence for the presence of liquid
surface water and even life in the Archean (3.8 to 2.5 billion years before
present), so some effect (or effects) must have been compensating for the faint
young Sun. A wide range of possible solutions have been suggested and explored
during the last four decades, with most studies focusing on higher
concentrations of atmospheric greenhouse gases like carbon dioxide, methane or
ammonia. All of these solutions present considerable difficulties, however, so
the faint young Sun problem cannot be regarded as solved. Here I review
research on the subject, including the latest suggestions for solutions of the
faint young Sun problem and recent geochemical constraints on the composition
of Earth's early atmosphere. Furthermore, I will outline the most promising
directions for future research. In particular I would argue that both improved
geochemical constraints on the state of the Archean climate system and
numerical experiments with state-of-the-art climate models are required to
finally assess what kept the oceans on the Archean Earth from freezing over
completely.Comment: 32 pages, 8 figures. Invited review paper accepted for publication in
Reviews of Geophysic
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