16,575 research outputs found
A feasibility study: Forest Fire Advanced System Technology (FFAST)
The National Aeronautics and Space Administration/Jet Propulsion Laboratory and the United States Department of Agriculture Forest Service completed a feasibility study that examined the potential uses of advanced technology in forest fires mapping and detection. The current and future (1990's) information needs in forest fire management were determined through interviews. Analysis shows that integrated information gathering and processing is needed. The emerging technologies that were surveyed and identified as possible candidates for use in an end to end system include ""push broom'' sensor arrays, automatic georeferencing, satellite communication links, near real or real time image processing, and data integration. Matching the user requirements and the technologies yielded a ""strawman'' system configuration. The feasibility study recommends and outlines the implementation of the next phase for this project, a two year, conceptual design phase to define a system that warrants continued development
Association between obesity and bacterial vaginosis as assessed by Nugent score
Background
Bacterial vaginosis is one of the most common vaginal conditions in the U.S. Recent studies have suggested obese women have an abnormal microbiota reminiscent of BV; however, few studies have investigated the prevalence of bacterial vaginosis in overweight and obese populations. Moreover, despite the increased prevalence of obesity and bacterial vaginosis in black women, it is not known whether racial disparities exist in the relationship between obesity and bacterial vaginosis.
Objective
The objective of this study was to examine the relationship between body mass index and bacterial vaginosis as determined by Nugent score and to determine the influence of race in this context.
Study Design
We performed a cross-sectional study using patient data and vaginal smears from 5,918 participants of the Contraceptive CHOICE Project. Gram stained vaginal smears were scored using the Nugent method and categorized as BV-negative (Nugent score 0-3), BV-intermediate (Nugent score 4-6), or BV-positive (Nugent score 7-10). Body mass index was determined using Centers for Disease Control and Prevention guidelines and obese individuals were categorized as Class I, II, or III obese based on NIH and World Health Organization body mass index parameters. Linear regression was used to model mean differences in Nugent scores and Poisson regression with robust error variance was used to model prevalence of bacterial vaginosis.
Results
In our cohort, 50.7% of participants were black, 41.5% were white, and 5.1% were of Hispanic ethnicity with an average age of 25.3 years old. Overall, 28.1% of participants were bacterial vaginosis-positive. Bacterial vaginosis was prevalent in 21.3% of lean, 30.4% of overweight, and 34.5% of obese women (p<0.001). The distribution of bacterial vaginosis-intermediate individuals was similar across all body mass index categories. Compared to lean women, Nugent scores were highest among overweight and obese Class I women (adjusted mean difference; overweight 0.33 [95% CI 0.14, 0.51] and Class I obese 0.51 [95% CI 0.29, 0.72]). Consistent with this, overweight and obese women had a higher frequency of bacterial vaginosis compared to lean women, even after adjusting for variables including race. Among white women, the prevalence of BV was higher for overweight and Class I and Class II/III obese white women compared to lean white women, a phenomenon not observed among black women, suggesting an effect modification.
Conclusion
Overweight and obese women have higher Nugent scores and a greater occurrence of bacterial vaginosis compared to lean women. Black women have a greater prevalence of bacterial vaginosis independent of their body mass index compared to white women
Submicrosecond comparison of international clock synchronization by VLBI and the NTS satellite
The intercontinental clock synchronization capabilities of Very Long Baseline Interferometry (VLBI) and the Navigation Technology Satellite (NTS) were compared using both methods to synchronize the Cesium clocks at the NASA Deep Space Net complexes at Madrid, Spain and Goldstone, California. Verification of the accuracy of both systems was examined. The VLBI experiments used the Wideband VLBI Data Acquisition System developed at the NASA Jet Propulsion Laboratory. The NTS Satellites were designed and built by the Naval Research Laboratory used with NTS Timing Receivers developed by the Goddard Space Flight Center. The two methods agreed at about the one-half microsecond level
Accretion Disks Around Young Objects. III. Grain Growth
We present detailed models of irradiated T Tauri disks including dust grain
growth with power-law size distributions. The models assume complete mixing
between dust and gas and solve for the vertical disk structure
self-consistentlyincluding the heating effects of stellar irradiation as well
as local viscous heating. For a given total dust mass, grain growth is found to
decrease the vertical height of the surface where the optical depth to the
stellar radiation becomes unit and thus the local irradiation heating, while
increasing the disk emission at mm and sub-mm wavelengths. The resulting disk
models are less geometrically thick than our previous models assuming
interstellar medium dust, and agree better with observed spectral energy
distributions and images of edge-on disks, like HK Tau/c and HH 30. The
implications of models with grain growth for determining disk masses from
long-wavelength emission are considered.Comment: 29 pages, including 11 figures and 1 table, APJ accepte
Decomposition of the visible and dark matter in the Einstein ring 0047-2808 by semi-linear inversion
We measure the mass density profile of the lens galaxy in the Einstein ring
system 0047-2808 using our semi-linear inversion method developed in an earlier
paper. By introducing an adaptively gridded source plane, we are able to
eliminate the need for regularisation of the inversion. This removes the
problem of a poorly defined number of degrees of freedom, encountered by
inversion methods that employ regularisation, and so allows a proper
statistical comparison between models. We confirm the results of Wayth et al.
(2004), that the source is double, and that a power-law model gives a
significantly better fit that the singular isothermal ellipsoid model. We
measure a slope alpha=2.11+/-0.04. We find, further, that a dual-component
constant M/L baryonic + dark halo model gives a significantly better fit than
the power-law model, at the 99.7% confidence level. The inner logarithmic slope
of the dark halo profile is found to be 0.87^{+0.69}_{-0.61} (95% CL),
consistent with the predictions of CDM simulations of structure formation. We
determine an unevolved B-band mass to light ratio for the baryons (only) of
3.05^{+0.53}_{-0.90} h_65 M_sol/L_Bsol (95% CL). This is the first measurement
of the baryonic M/L of a single galaxy by purely gravitational lens methods.
The baryons account for 65^{+10}_{-18}% (95% CL) of the total projected mass,
or, assuming spherical symmetry, 84^{+12}_{-24}% (95% CL) of the total
three-dimensional mass within the mean radius of 1.16'' (7.5 h_65^{-1} kpc)
traced by the ring. Finally, at the level of >3sigma, we find that the halo
mass is rounder than the baryonic distribution and that the two components are
offset in orientation from one another.Comment: 17 pages, 5 figures, accepted by ApJ on 17/12/05. This version
corrects various typo
Flows and Non-thermal Velocities in Solar Active Regions Observed with the Extreme-ultraviolet Imaging Spectrometer on Hinode: A Tracer of Active Region Sources of Heliospheric Magnetic Fields?
From Doppler velocity maps of active regions constructed from spectra
obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode
spacecraft we observe large areas of outflow (20-50 km/s) that can persist for
at least a day. These outflows occur in areas of active regions that are faint
in coronal spectral lines formed at typical quiet Sun and active region
temperatures. The outflows are positively correlated with non-thermal
velocities in coronal plasmas. The bulk mass motions and non-thermal velocities
are derived from spectral line centroids and line widths, mostly from a strong
line of Fe XII at 195.12 Angstroms. The electron temperature of the outflow
regions estimated from an Fe XIII to Fe XII line intensity ratio is about
1.2-1.4 MK. The electron density of the outflow regions derived from a density
sensitive intensity ratio of Fe XII lines is rather low for an active region.
Most regions average around 7E10+8 cm(-3), but there are variations on pixel
spatial scales of about a factor of 4. We discuss results in detail for two
active regions observed by EIS. Images of active regions in line intensity,
line width, and line centroid are obtained by rastering the regions. We also
discuss data from the active regions obtained from other orbiting spacecraft
that support the conclusions obtained from analysis of the EIS spectra. The
locations of the flows in the active regions with respect to the longitudinal
photospheric magnetic fields suggest that these regions might be tracers of
long loops and/or open magnetic fields that extend into the heliosphere, and
thus the flows could possibly contribute significantly to the solar wind.Comment: one tex file, 11 postscript figure file
The Discovery of a Companion to the Lowest Mass White Dwarf
We report the detection of a radial velocity companion to SDSS
J091709.55+463821.8, the lowest mass white dwarf currently known with
M~0.17Msun. The radial velocity of the white dwarf shows variations with a
semi-amplitude of 148.8 km/s and a period of 7.5936 hours, which implies a
companion mass of M > 0.28Msun. The lack of evidence of a companion in the
optical photometry forces any main-sequence companion to be smaller than
0.1Msun, hence a low mass main sequence star companion is ruled out for this
system. The companion is most likely another white dwarf, and we present
tentative evidence for an evolutionary scenario which could have produced it.
However, a neutron star companion cannot be ruled out and follow-up radio
observations are required to search for a pulsar companion.Comment: ApJ, in press. See the Press Release at
http://www.cfa.harvard.edu/press/2007/pr200708.htm
The Relationship between Just World Beliefs and Life Satisfaction
An important and often unexplored factor shaping life satisfaction is one’s perception of the world as a “just” place. The “just world hypothesis” is predicated on the idea that the world works as a place where people get what they merit, an idea that often serves as a means for people to rationalize injustices. The research addressing just world beliefs has expanded into a four-factor model that categorizes just world beliefs for self and others into subcategories of distributive and procedural justice. Distributive justice involves evaluations of the fairness of outcomes, allocations, or distribution of resources, while procedural concerns evaluations of the fairness of decision processes, rules, or interpersonal treatment. This study explored the relationship between the four just world beliefs subscales and overall satisfaction with life and examined their associations with demographic variables including ethnicity, age, gender, religion, and social class. The relationships of demographic factors with justice beliefs and life satisfaction generally yielded very small effect sizes. However, respondents who identified themselves as middle and upper class reported higher levels of life satisfaction than those who identified themselves as lower class, with a medium effect size. Consistent with the results of earlier research, regressing life satisfaction on the four justice beliefs subscales indicated that the two self-subscales (distributive and procedural) were significantly predictive of life satisfaction, but the two other subscales (distributive and procedural) were not
Brief mindfulness training enhances cognitive control in socioemotional contexts: Behavioral and neural evidence.
In social contexts, the dynamic nature of others' emotions places unique demands on attention and emotion regulation. Mindfulness, characterized by heightened and receptive moment-to-moment attending, may be well-suited to meet these demands. In particular, mindfulness may support more effective cognitive control in social situations via efficient deployment of top-down attention. To test this, a randomized controlled study examined effects of mindfulness training (MT) on behavioral and neural (event-related potentials [ERPs]) responses during an emotional go/no-go task that tested cognitive control in the context of emotional facial expressions that tend to elicit approach or avoidance behavior. Participants (N = 66) were randomly assigned to four brief (20 min) MT sessions or to structurally equivalent book learning control sessions. Relative to the control group, MT led to improved discrimination of facial expressions, as indexed by d-prime, as well as more efficient cognitive control, as indexed by response time and accuracy, and particularly for those evidencing poorer discrimination and cognitive control at baseline. MT also produced better conflict monitoring of behavioral goal-prepotent response tendencies, as indexed by larger No-Go N200 ERP amplitudes, and particularly so for those with smaller No-Go amplitude at baseline. Overall, findings are consistent with MT's potential to enhance deployment of early top-down attention to better meet the unique cognitive and emotional demands of socioemotional contexts, particularly for those with greater opportunity for change. Findings also suggest that early top-down attention deployment could be a cognitive mechanism correspondent to the present-oriented attention commonly used to explain regulatory benefits of mindfulness more broadly
The internal structure and formation of early-type galaxies: the gravitational--lens system MG2016+112 at z=1.004
[Abridged] We combine our measurements of the velocity dispersion and the
surface brightness profile of the lens galaxy D in the system MG2016+112
(z=1.004) with constraints from gravitational lensing to study its internal
mass distribution. We find that: (i) dark matter accounts for >50% of the total
mass within the Einstein radius (99% CL), excluding at the 8-sigma level that
mass follows light inside the Einstein radius with a constant mass-to-light
ratio (M/L). (ii) the total mass distribution inside the Einstein radius is
well-described by a density profile ~r^-gamma' with an effective slope
gamma'=2.0+-0.1+-0.1, including random and systematic uncertainties. (iii) The
offset of galaxy D from the local Fundamental Plane independently constrains
the stellar M/L, and matches the range derived from our models, leading to a
more stringent lower limit of >60% on the fraction of dark matter within the
Einstein radius (99%CL).
Under the assumption of adiabatic contraction, the inner slope of the dark
matter halo before the baryons collapsed is gamma_i<1.4 (68 CL), marginally
consistent with the highest-resolution cold dark matter simulations that
indicate gamma_i~1.5. This might indicate that either adiabatic contraction is
a poor description of E/S0 formation or that additional processes play a role
as well. Indeed, the apparently isothermal density distribution inside the
Einstein radius, is not a natural outcome of adiabatic contraction models,
where it appears to be a mere coincidence. By contrast, we argue that
isothermality might be the result of a stronger coupling between luminous and
dark-matter, possibly the result of (incomplete) violent relaxation processes.
Hence, we conclude that galaxy D appears already relaxed 8 Gyr ago.Comment: 8 pages, 4 figures, ApJ, in press, minor change
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