2,132 research outputs found
An Exact No Free Lunch Theorem for Community Detection
A precondition for a No Free Lunch theorem is evaluation with a loss function
which does not assume a priori superiority of some outputs over others. A
previous result for community detection by Peel et al. (2017) relies on a
mismatch between the loss function and the problem domain. The loss function
computes an expectation over only a subset of the universe of possible outputs;
thus, it is only asymptotically appropriate with respect to the problem size.
By using the correct random model for the problem domain, we provide a
stronger, exact No Free Lunch theorem for community detection. The claim
generalizes to other set-partitioning tasks including core/periphery
separation, -clustering, and graph partitioning. Finally, we review the
literature of proposed evaluation functions and identify functions which
(perhaps with slight modifications) are compatible with an exact No Free Lunch
theorem
Biomedical applications team tasks
The status of the biomedical applications team is discussed along with its activity in applications engineering. Various technology requests are summarized
Planck Observations of M33
We have performed a comprehensive investigation of the global integrated flux
density of M33 from radio to ultraviolet wavelengths, finding that the data
between 100 GHz and 3 THz are accurately described by a single modified
blackbody curve with a dust temperature of = 21.670.30 K
and an effective dust emissivity index of = 1.350.10,
with no indication of an excess of emission at millimeter/sub-millimeter
wavelengths. However, sub-dividing M33 into three radial annuli, we found that
the global emission curve is highly degenerate with the constituent curves
representing the sub-regions of M33. We also found gradients in
and across the disk of M33, with both
quantities decreasing with increasing radius. Comparing the M33 dust emissivity
with that of other Local Group members, we find that M33 resembles the
Magellanic Clouds rather than the larger galaxies, i.e., the Milky Way and M31.
In the Local Group sample, we find a clear correlation between global dust
emissivity and metallicity, with dust emissivity increasing with metallicity. A
major aspect of this analysis is the investigation into the impact of
fluctuations in the Cosmic Microwave Background (CMB) on the integrated flux
density spectrum of M33. We found that failing to account for these CMB
fluctuations would result in a significant over-estimate of
by 5 K and an under-estimate of by 0.4.Comment: Accepted for publication in MNRA
ADOPTION OF BEST MANAGEMENT PRACTICES IN STOCKER CATTLE PRODUCTION
This study identifies current production and management practices of Oklahoma stocker cattle producers and analyzes factors affecting the adoption of best management practices (BMPs) using chi-square analysis. Results reveal that factors influencing the adoption of BMPs are operation size, dependency upon income from the operation, and specialization in stocker production.cattle, stockers, management, production, Livestock Production/Industries,
Transport and Spectroscopic Studies of the Effects of Fullerene Structure on the Efficiency and Lifetime of Polythiophene-based Solar Cells
Time-dependent measurements of both power conversion efficiency and
ultraviolet-visible absorption spectroscopy have been observed for solar cell
blends containing the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) with two
different functionalized C60 electron acceptor molecules: commercially
available [6,6]-phenyl C61 butyric acid methyl ester (PCBM) or [6,6]-phenyl C61
butyric acid octadecyl ester (PCBOD) produced in this laboratory. Efficiency
was found to decay with an exponential time dependence, while spectroscopic
features show saturating exponential behavior. Time constants extracted from
both types of measurements showed reasonable agreement for samples produced
from the same blend. In comparison to the PCBM samples, the stability of the
PCBOD blends was significantly enhanced, while both absorption and power
conversion efficiency were decreased.Comment: manuscript submitted to Solar Energy Materials and Solar Cell
Compression failure of angle-ply laminates
Test results from the compression loading of (+ or - Theta/ - or + Theta)(sub 6s) angle-ply IM7-8551-7a specimens, 0 less than or = Theta less than or = 90 degs, are presented. The observed failure strengths and modes are discussed, and typical stress-strain relations shown. Using classical lamination theory and the maximum stress criterion, an attempt is made to predict failure stress as a function of Theta. This attempt results in poor correlation with test results and thus a more advanced model is used. The model, which is based on a geometrically nonlinear theory, and which was taken from previous work, includes the influence of observed layer waviness. The waviness is described by the wave length and the wave amplitude. The theory is briefly described and results from the theory are correlated with test results. It is shown that by using levels of waviness observed in the specimens, the correlation between predictions and observations is good
Exposure to Household Air Pollution from Biomass-Burning Cookstoves and HbA1c and Diabetic Status Among Honduran Women
Household air pollution from biomass cookstoves is estimated to be responsible for more than two and a half million premature deaths annually, primarily in low and middleâincome countries where cardiometabolic disorders, such as Type II Diabetes, are increasing. Growing evidence supports a link between ambient air pollution and diabetes, but evidence for household air pollution is limited. This crossâsectional study of 142 women (72 with traditional stoves and 70 with cleanerâburning Justa stoves) in rural Honduras evaluated the association of exposure to household air pollution (stove type, 24âhour average kitchen and personal fine particulate matter [PM2.5] mass and black carbon) with glycated hemoglobin (HbA1c) levels and diabetic status based on HbA1c levels. The prevalence ratio (PR) per interquartile range increase in pollution concentration indicated higher prevalence of prediabetes/diabetes (vs normal HbA1c) for all pollutant measures (eg, PR per 84 ÎŒg/m3 increase in personal PM2.5, 1.49; 95% confidence interval [CI], 1.11â2.01). Results for HbA1c as a continuous variable were generally in the hypothesized direction. These results provide some evidence linking household air pollution with the prevalence of prediabetes/diabetes, and, if confirmed, suggest that the global public health impact of household air pollution may be broader than currently estimated
Advanced sensors technology survey
This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed
Exposure to Household Air Pollution from Biomass Cookstoves and Blood Pressure Among Women in Rural Honduras: A CrossâSectional Study
Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed crossâsectional associations of 24âhour mean concentrations of personal and kitchen fine particulate matter (PM2.5), black carbon (BC), and stove type with blood pressure, adjusting for confounders, among 147 women using traditional or cleanerâburning Justa stoves in Honduras. We investigated effect modification by age and body mass index. Traditional stove users had mean (standard deviation) personal and kitchen 24âhour PM2.5 concentrations of 126 ÎŒg/m3 (77) and 360 ÎŒg/m3 (374), while Justa stove usersâ exposures were 66 ÎŒg/m3 (38) and 137 ÎŒg/m3(194), respectively. BC concentrations were similarly lower among Justa stove users. Adjusted mean systolic blood pressure was 2.5 mm Hg higher (95% CI, 0.7â4.3) per unit increase in natural logâtransformed kitchen PM2.5 concentration; results were stronger among women of 40 years or older (5.2 mm Hg increase, 95% CI, 2.3â8.1). Adjusted odds of borderline high and high blood pressure (categorized) were also elevated (odds ratio = 1.5, 95% CI, 1.0â2.3). Some results included null values and are suggestive. Results suggest that reduced household air pollution, even when concentrations exceed air quality guidelines, may help lower cardiovascular disease risk, particularly among older subgroups
Beyond prejudice: Are negative evaluations the problem and is getting us to like one another more the solution?
This is a post print version of an article published in Behavioral and Brain Sciences, 2012, 35 (6), pp 438-439 DOI: http://dx.doi.org/10.1017/S0140525X12001252
Copyright © Cambridge University Press 2012For most of the history of prejudice research, negativity has been treated as its emotional and cognitive signature, a conception that continues to dominate work on the topic. By this definition, prejudice occurs when we dislike or derogate members of other groups. Recent research, however, has highlighted the need for a more nuanced and âinclusiveâ (Eagly 2004) perspective on the role of intergroup emotions and beliefs in sustaining discrimination. On the one hand, several independent lines of research have shown that unequal intergroup relations are often marked by attitudinal complexity, with positive responses such as affection and admiration mingling with negative responses such as contempt and resentment. Simple antipathy is the exception rather than the rule. On the other hand, there is mounting evidence that nurturing bonds of affection between the advantaged and the disadvantaged sometimes entrenches rather than disrupts wider patterns of discrimination. Notably, prejudice reduction interventions may have ironic effects on the political attitudes of the historically disadvantaged, decreasing their perceptions of injustice and willingness to engage in collective action to transform social inequalities. These developments raise a number of important questions. Has the time come to challenge the assumption that negative evaluations are inevitably the cognitive and affective hallmarks of discrimination? Is the orthodox concept of prejudice in danger of side-tracking, if not obstructing, progress towards social justice in a fuller sense? What are the prospects for reconciling a prejudice reduction model of change, designed to get people to like one another more, with a collective action model of change, designed to ignite struggles to achieve intergroup equality
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