1,739 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
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 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
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
Study Protocol for a Stepped-Wedge Randomized Cookstove Intervention in Rural Honduras: Household Air Pollution and Cardiometabolic Health
Growing evidence links household air pollution exposure from biomass-burning cookstoves to cardiometabolic disease risk. Few randomized controlled interventions of cookstoves (biomass or otherwise) have quantitatively characterized changes in exposure and indicators of cardiometabolic health, a growing and understudied burden in low- and middle-income countries (LMICs). Ideally, the solution is to transition households to clean cooking, such as with electric or liquefied petroleum gas stoves; however, those unable to afford or to access these options will continue to burn biomass for the foreseeable future. Wood-burning cookstove designs such as the Justa (incorporating an engineered combustion zone and chimney) have the potential to substantially reduce air pollution exposures. Previous cookstove intervention studies have been limited by stove types that did not substantially reduce exposures and/or by low cookstove adoption and sustained use, and few studies have incorporated community-engaged approaches to enhance the intervention
Template fitting of WMAP 7-year data: anomalous dust or flattening synchrotron emission?
Anomalous microwave emission at 20-40 GHz has been detected across our
Galactic sky. It is highly correlated with thermal dust emission and hence it
is thought to be due to spinning dust grains. Alternatively, this emission
could be due to synchrotron radiation with a flattening (hard) spectral index.
We cross-correlate synchrotron, free-free and thermal dust templates with the
WMAP 7-year maps using synchrotron templates at both 408 MHz and 2.3 GHz to
assess the amount of flat synchrotron emission that is present, and the impact
that this has on the correlations with the other components. We find that there
is only a small amount of flattening visible in the synchrotron spectral
indices by 2.3 GHz, of around \Delta \beta ~ 0.05, and that the significant
level of dust-correlated emission in the lowest WMAP bands is largely
unaffected by the choice of synchrotron template, particularly at high
latitudes (it decreases by only ~7 per cent when using 2.3 GHz rather than 408
MHz). This agrees with expectation if the bulk of the anomalous emission is
generated by spinning dust grains.Comment: 11 pages, 6 figures, 6 tables. Published in MNRA
Fatty Acid Metabolism on Pasture- and Feedlot-Finished Cattle
Feeding high-grain diets to finishing beef cattle results in high proportions of saturated fatty acids (SFA) in the beef, which is considered to confer negative impacts on human health. In contrast, pasture-finished cattle produce lower proportion of SFA, greater n-3 and less n-6 polyunsaturated fatty acids (PUFA), and higher conjugated linoleic acids (CLA) compared to high grain-finished beef (Noviandi et al. 2012). Increased n-3 PUFA, especially C18:3 n-3, can reduce the risk of heart disease, hypertension, inflammation, and mammary cancer, and lower cholesterol concentration in blood (De Deckere et al. 1998; Tapiero et al. 2002).
Nitrogen fertilisation can increase biomass production and nitrogen (N) concentration of tall fescue (TF; Festuca arundinacea) (Berg and Sims 2000; Teuton et al. 2007), which positively affected beef cattle performance (Berg and Sims 1995). However, the metabolism of fatty acids (FA) in pasture-finished beef steers due to N fertilization on TF has not yet been studied. Therefore, the current study was performed to test a hypothesis that due to its potential impacts on nutrient and energy utilization, N fertilization would affect FA compositions in ruminal fluid, blood serum, and adipose tissue of pasture-finished beef steers. In addition, we were interested in beneficial effects of grazing steers by comparing the FA profiles between pasture- and feedlot-finished beef steers
Salinity Reduces the Forage Quality of Forage Kochia: A Halophytic Chenopodiaceae Shrub
Forage kochia (Bassia prostrata [L.] A.J. Scott) is a perennial, halophytic Chenopodiaceae shrub adapted to semiarid rangelands and steppes. It is noted for its ability to produce edible forage in saline environments, but the effect of salinity on its nutritive value has not been determined. Therefore, this study evaluated the dose-response of increasing salinity on the forage quality of forage kochia and Gardnerâs saltbush (Atriplex gardneri [Moq.] D. Dietr., a chenopod forage shrub indigenous to the United States). Individual plants were evaluated in hydroponics for 28 days at 0, 150, 300, and 600 mM NaCl. Salt from accumulated ions, minerals, and forage nutritive value were determined using ground shoot samples. Analysis of forage nutritive value is problematic in plants with high salt concentrations, so neutral detergent fiber (NDF) and in vitro true digestibility (IVTD) were also predicted on an ash-corrected dry matter (DM) basis (NDFcorrected and IVTDcorrected). Forage kochia exhibited a dose-response for salt concentration, IVTDcorrected, and crude protein (CP) as salinity increased. Salt concentrations increased to 19% of DM at 600 mM NaCl, which may reduce voluntary intake by ruminants grazing forage kochia. Results indicated that uncorrected IVTD estimates were inflated as forage kochia IVTDcorrected decreased from 65% to 56% with the major change between 300 and 600 mM NaCl. Crude protein did not differ between two forage kochia cultivars but decreased from 26% to 15% between 0 and 600 mM NaCl, whereas Gardnerâs saltbush CP decreased by only five percentage points as salinity increased. Nonetheless, despite the greater CP sensitivity to salinity level, forage kochia salt concentration was less and digestibility and metabolizable energy (ME) were greater than Gardnerâs saltbush. Overall, salinity reduced the forage quality of forage kochia, though not as dramatically as for Gardnerâs saltbush, thus supporting use of forage kochia to improve the forage base of saline rangelands
O errar na aprendizagem da lĂngua portuguesa
Nossa proposta consiste na discussĂŁo do conceito de aprendizagem da norma padrĂŁo da lĂngua portuguesa, refletindo basicamente sobre desvios e erros no ambiente da Educação Fundamental. Em relação Ă s experimentaçÔes cotidianas da sala de aula, entendemos que o errar e o desviar de trajetos impostos pelo sistema podem ser usados como procedimentos cartogrĂĄficos para a aprendizagem da normatividade grama- tical. Muitos dos que passam pelo processo de escolarização nĂŁo conseguem se manifestar de forma crĂtica, normativa e autĂŽnoma nas suas vivĂȘncias cotidianas dos aspectos sociais e polĂticos; percebemos que muitas vezes esses problemas advĂȘm da ausĂȘncia de afetos positivos no ambiente educacional, e, a partir disso, desenvolvemos as seguintes questĂ”es de investigação: Como o erro afeta os sujeitos em processo de aprendizagem da lĂngua portuguesa? Como a relação afetiva com a lĂngua portuguesa pode reterritorializar a aprendizagem, transformando-a em uma potĂȘncia positiva? Por que alguns desvios em relação Ă norma padrĂŁo nĂŁo sĂŁo percebidos pelos utentes linguĂsticos? Para encontrar respostas, promovemos um agenciamento entre os seguintes autores: Spinoza, Nietzsche, Deleuze, Guattari, Freire e Sen, dentre outros; almejando encontros e intercessores rizomĂĄticos sobre a aprendizagem e sobre o errar enquanto cartografias de trajetos afetuosos e efetivos de um sujeito livre.Our proposal consists of a discussion of the concept of learning the standard norm of Portuguese language, essentially reflecting on detours and errors in the Primary Education environment. With reference to everyday experiences in the classroom, we perceive that the activities of making errors and taking detours from paths imposed by the system can be used as cartographic procedures for the learning of grammar norms. Many of those who follow the schooling process are not able to express themselves using critical thinking, according to norms and autonomously in their everyday experiences of social and political aspects; we realize that these problems frequently emerge due to the absence of positive affections in the educational environment, which has lead to the following research questions: How does making errors affect subjects in the learning process of the Portuguese language? How can having an affective relationship with the Portuguese language reterritorialise learning, transforming it into a positive power (potentia)? Why arenât some detours in relation to the standard norm noticeable by language users? In order to find answers, we enhance an assemblage of the following authors: Spinoza, Nietzsche, Deleuze, Guattari, Freire and Sen, among others; aiming at connections and rhizomatic interactions on learning and on making errors as cartographies of affective and effective paths of a freeperson.info:eu-repo/semantics/publishedVersio
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