688 research outputs found
Adipose Tissue Distribution and Survival Among Women with Nonmetastatic Breast Cancer.
ObjectivePrevious studies of breast cancer survival have not considered specific depots of adipose tissue such as subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT).MethodsThis study assessed these relationships among 3,235 women with stage II and III breast cancer diagnosed between 2005 and 2013 at Kaiser Permanente Northern California and between 2000 and 2012 at Dana Farber Cancer Institute. SAT and VAT areas (in centimeters squared) were calculated from routine computed tomography scans within 6 (median: 1.2) months of diagnosis, covariates were collected from electronic health records, and vital status was assessed by death records. Hazard ratios (HRs) and 95% CIs were estimated using Cox regression.ResultsSAT and VAT ranged from 19.0 to 891 cm2 and from 0.484 to 454 cm2 , respectively. SAT was related to increased risk of death (127-cm2 increase; HR [95% CI]: 1.13 [1.02-1.26]), but no relationship was found with VAT (78.18-cm2 increase; HR [95% CI]: 1.02 [0.91-1.14]). An association with VAT was noted among women with stage II cancer (stage II: HR: 1.17 [95% CI: 0.99-1.39]; stage III: HR: 0.90 [95% CI: 0.76-1.07]; P interaction < 0.01). Joint increases in SAT and VAT were associated with mortality above either alone (simultaneous 1-SD increase: HR 1.19 [95% CI: 1.05-1.34]).ConclusionsSAT may be an underappreciated risk factor for breast cancer-related death
Gender, economics and culture: diversity and the international evolution of smoking prevalence
Aims: To examine whether the observed diversity between national patterns of smoking prevalence could require modification of the World Health Organization (WHO) linear model for an international `smoking pandemic' (a worldwide epidemic) to address data from non-western countries.
Method: We conducted secondary research using current measures in three publicly available databases: Globalink, the International Labour Organization and the World Bank (all internetaccessible). The measures we used are the separate percentage data for men and women on: smoking and employment and national income per capita (US$) and percentage growth per annum.
Results: Regression analysis showed that women smokers were more frequent in countries with higher national income, but women were less likely to smoke in countries of rapid growth. Men were less likely to smoke in countries with higher national income, but more likely to smoke in countries of rapid growth. Two principle components together explained 62% of all the variance in the international data. The largest factor was positively correlated with the percentage of employed females, the percentage of female smokers and national income per capita, but negatively correlated with the percentage of male smokers and percentage annual growth. The effect of female employment was not continuous, but above a threshold of 51%, was associated with a higher prevalence of female smoking. The smaller, second factor was only weakly correlated with any smoking variables.
Conclusions: In his 1994 model (subsequently adopted by the WHO) Lopez looked at historical trends in `stages' of smoking prevalence. These have been associated with `stages' of economic development. We extended this analysis to look at a dynamic change (% annual growth) and a social indicator (employment). Male and female smoking is affected differentially by economic change and by level of income. These are also strongly related to the percentage of women in employment. This has implications for workplace policies on smoking
No evidence for externally triggered substorms based on superposed epoch analysis of IMF Bz
Superposed epoch analyses have shown that, on average, the interplanetary magnetic field (IMF) turns northward close to substorm onset. This has been commonly accepted as evidence for the substorm onset being triggered by a rapid northward turning of the IMF. Here we show that the tendency arises in any superposed epoch analysis of the IMF in which event onset is biased to occur for southward IMF, irrespective of a coincident rapid northward turning of the IMF. The overall IMF variation found in the largest superposed epoch analysis of this kind is also well reproduced using a Minimal Substorm Model in which substorm onsets are determined without the requirement of a northward IMF turning trigger. We discuss the explanation underlying these results and conclude that there is no conclusive evidence in favour of the hypothesis that substorm onsets are triggered by a rapid northward turning of the IMF. Citation: Freeman, M. P., and S. K. Morley (2009), No evidence for externally triggered substorms based on superposed epoch analysis of IMF B-z, Geophys. Res. Lett., 36, L21101, doi: 10.1029/2009GL040621
Does higher sampling rate (multiband + SENSE) improve group statistics - An example from social neuroscience block design at 3T
Sparse classification with MRI based markers for neuromuscular disease categorization
International audienceIn this paper, we present a novel method for disease classification between two patient populations based on features extracted from Magnetic Resonance Imaging (MRI) data. Anatomically meaningful features are extracted from structural data (T1- and T2-weighted MR images) and Diffusion Tensor Imaging (DTI) data, and used to train a new machine learning algorithm, the k-support SVM (ksup-SVM). The k-support regularized SVM has an inherent feature selection property, and thus it eliminates the requirement for a separate feature selection step. Our dataset consists of patients that suffer from facioscapulohumeral muscular dystrophy (FSH) and Myotonic muscular dystrophy type 1 (DM1) and our proposed method achieves a high performance. More specifically, it achieves a mean Area Under the Curve (AUC) of 0.7141 and mean accuracy 77% ± 0.013. Moreover, we provide a sparsity visualization of the features in order to indentify their discriminative value. The results suggest the potential of the combined use of MR markers to diagnose myopathies, and the general utility of the ksup-SVM. Source code is also available at https://gitorious.org/ksup-svm
Scaling of solar wind e and the AU, AL and AE indices as seen by WIND
We apply the finite size scaling technique to quantify the statistical properties of fluctuations in AU, AL and AE indices and in the parameter that represents energy input from the solar wind into the magnetosphere. We find that the exponents needed to rescale the probability density functions (PDF) of the fluctuations are the same to within experimental error for all four quantities. This self-similarity persists for time scales up to ~4 hours for AU, AL and and up to ~2 hours for AE. Fluctuations on shorter time scales than these are found to have similar long-tailed (leptokurtic) PDF, consistent with an underlying turbulent process. These quantitative and model-independent results place important constraints on models for the coupled solar wind-magnetosphere system
A high-resolution multi-shell 3T diffusion magnetic resonance imaging dataset as part of the Amsterdam Ultra-high field adult lifespan database (AHEAD)
In order to further our understanding of brain function and the underlying networks, more advanced diffusion weighted magnetic resonance imaging (DWI MRI) data are essential. Here we present freely available high-resolution multi-shell multi-directional 3 Tesla (T) DWI MRI data as part of the 'Amsterdam Ultra-high field adult lifespan database' (AHEAD). The 3T DWI AHEAD dataset include 1.28mm isotropic whole brain DWI data of 49 healthy adult participants between 18 and 90 years old. The acquired data include DWIs at three non-zero b-values (48 directions, b-value 700 s/mm2; 56 directions, b-value 1000 s/mm2; 64 directions, b-value 1600 s/mm2) including a total of twelve volumes with a b-value of 0 s/mm2 (b0 volumes). In addition, eight b0 volumes with a reversed phase encoding direction were acquired to correct for distortions. To facilitate future use, the DWI data have been denoised, corrected for eddy currents, susceptibility-induced off-resonance field distortions, bias fields, and are skull stripped
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