610 research outputs found
Physical activity in daily life is associated with lower adiposity values than doing weekly sports in Lc65+ cohort at baseline.
BACKGROUND: Overweight and obesity prevalence is the highest at age 65-75 years in Lausanne (compared with younger classes). We aimed to describe 1) eating habits, daily physical activity (PA), and sports frequency in community-dwelling adults aged 65-70, 2) the links of these behaviors with socio-economic factors, and 3) with adiposity.
METHODS: Cross-sectional analysis of Lc65+ cohort at baseline, including 1260 adults from the general population of Lausanne aged 65-70 years. Eating habits (8 items from MNA) and PA (sports frequency and daily PA: walking and using stairs) were assessed by questionnaires. Body mass index (BMI), supra-iliac (SISF), triceps skin-folds (TSF), waist circumference (WC), and WHR were measured.
RESULTS: Prevalence of overweight (BMI 25.0-29.9 kg/m2), obesity (BMI ≥ 30.0 kg/m2), and abdominal obesity was 53%, 24%, and 45% in men; 35%, 23%, and 45% in women.Intake of fruits or vegetables (FV) ≥ twice/day was negatively associated with male sex (prevalence 81% versus 90%, chi-square P < 0.001). The proportion avoiding stairs in daily life was higher among women (25%) than among men (20%, chi-square P=0.003).In multivariate analyses among both sexes, eating FV, using stairs in daily life ("stairs"), and doing sports ≥ once/week were significantly negatively associated with financial difficulties (stairs: OR=0.54, 95% CI=0.40-0.72) and positively with educational level (stairs: OR=1.68, 95% CI=1.17-2.43 for high school).For all five log-transformed adiposity indicators in women, and for all indicators except SISF and TSF in men, a gradual decrease in adiposity was observed from category "no stairs, sports < once/week" (reference), to "no stairs, sports ≥ once/week", to "stairs, sports < once/week", and "stairs, sports ≥ once/week" (for example: WC in men, respectively: ß= -0.03, 95% CI= -0.07-0.02; ß= -0.06, 95% CI= -0.09- -0.03; ß= -0.10, 95% CI= -0.12- -0.07).
CONCLUSIONS: In this population with high overweight and obesity prevalence, eating FV and PA were strongly negatively associated with financial difficulties and positively with education. Using stairs in daily life was more strongly negatively associated with adiposity than doing sports ≥ once/week
Traction force microscopy with optimized regularization and automated Bayesian parameter selection for comparing cells
Adherent cells exert traction forces on to their environment, which allows
them to migrate, to maintain tissue integrity, and to form complex
multicellular structures. This traction can be measured in a perturbation-free
manner with traction force microscopy (TFM). In TFM, traction is usually
calculated via the solution of a linear system, which is complicated by
undersampled input data, acquisition noise, and large condition numbers for
some methods. Therefore, standard TFM algorithms either employ data filtering
or regularization. However, these approaches require a manual selection of
filter- or regularization parameters and consequently exhibit a substantial
degree of subjectiveness. This shortcoming is particularly serious when cells
in different conditions are to be compared because optimal noise suppression
needs to be adapted for every situation, which invariably results in systematic
errors. Here, we systematically test the performance of new methods from
computer vision and Bayesian inference for solving the inverse problem in TFM.
We compare two classical schemes, L1- and L2-regularization, with three
previously untested schemes, namely Elastic Net regularization, Proximal
Gradient Lasso, and Proximal Gradient Elastic Net. Overall, we find that
Elastic Net regularization, which combines L1 and L2 regularization,
outperforms all other methods with regard to accuracy of traction
reconstruction. Next, we develop two methods, Bayesian L2 regularization and
Advanced Bayesian L2 regularization, for automatic, optimal L2 regularization.
Using artificial data and experimental data, we show that these methods enable
robust reconstruction of traction without requiring a difficult selection of
regularization parameters specifically for each data set. Thus, Bayesian
methods can mitigate the considerable uncertainty inherent in comparing
cellular traction forces
Protecting identity documents by microstructure color differences
The development of plastic card printers has led to the widespread use of identity documents printed on plastic cards, such as ID cards, driving licenses, and access key cards. This paper presents a new security feature based on a technique for embedding a personalized microstructure into an image. This microstructure takes the form of a pattern embedded into the original photograph as a succession of balanced chromatic shifts. The amplitude of these shifts may be tuned so as to make the pattern fully apparent or just noticeable under normal viewing conditions. Since the chromatic shifts cancel each other out in any macroscopic portion of the image, the global appearance of the protected image remains intact. The embedded microstructure may be adapted to each instance of the protected identity document. For example, it can repeat textual information already present elsewhere on the document, or it can include a code derived from data specific to the document holder. Furthermore, this information may be made fully readable without requiring special revealing means. Such identity documents exhibit an intrinsic resistance against imitation, tampering and substitution
Association between Adiposity and disability in the Lc65+ Cohort.
To examine the longitudinal association between body mass index (BMI) and waist circumference (WC) with mortality and incident disability in Lc65+ cohort.
Population-based cohort of non-institutionalized adults with up to 8.9 years of follow-up.
City of Lausanne, Switzerland.
1,293 individuals aged 65 to 70 at baseline (58% women).
BMI, WC and covariates were measured at baseline in 2004-2005. Vital status was obtained up to the 31st December 2013 and difficulty with basic activities of daily living (BADL) was reported in a self-administered questionnaire sent to participants every year. Main outcomes were total mortality and disability, defined as difficulty with BADL for ≥2 years or institutionalization. Cox regression was used with BMI/WC quintiles 2 as the reference.
130 persons died over a median follow-up of 8.47 years (crude mortality rate, men: 16.5/1,000 person-years, women: 9.7/1,000 person-years). In Cox regression adjusted for age, sex, education, financial situation, smoking and involuntary weight loss (IWL) at baseline, mortality was significantly associated with neither BMI nor WC, but there were trends towards non-significant J-curves across both BMI and WC quintiles. Disability (231 cases) tended to increase monotonically across both BMI and WC quintiles and was significantly associated with BMI quintile 5 (HR=2.44, 95% CI [1.65-3.63]), and WC quintiles 4 (HR=1.81 [1.15-2.85]) and 5 (HR=2.58, [1.67-4.00]).
Almost half of the study population had a substantially increased HR of disability, as compared to the reference BMI/WC categories. This observation emphasizes the need for life-long strategies aimed at preventing excess weight, muscle loss and functional decline through adequate nutrition and regular physical activity, starting at early age and extending throughout life
Influence of diffraction on the spectrum and wavefunctions of an open system
In this paper, we demonstrate the existence and significance of diffractive
orbits in an open microwave billiard, both experimentally and theoretically.
Orbits that diffract off of a sharp edge of the system are found to have a
strong influence on the transmission spectrum of the system, especially in the
regime where there are no stable classical orbits. On resonance, the
wavefunctions are influenced by both classical and diffractive orbits. Off
resonance, the wavefunctions are determined by the constructive interference of
multiple transient, nonperiodic orbits. Experimental, numerical, and
semiclassical results are presented.Comment: 27 pages, 29 figures, and 3 tables. Submitted to Physical Review E. A
copy with higher resolution figures is available at
http://monsoon.harvard.edu/~hersch/papers.htm
Public opinions about overdiagnosis:A national community survey
Despite evidence about the "modern epidemic" of overdiagnosis, and expanding disease definitions that medicalize more people, data are lacking on public views about these issues. Our objective was to measure public perceptions about overdiagnosis and views about financial ties of panels setting disease definitions.We conducted a 15 minute Computer Assisted Telephone Interview with a randomly selected community sample of 500 Australians in January 2014. We iteratively developed and piloted a questionnaire, with a convenience sample (n=20), then with participants recruited by a research company (n=20). Questions included whether respondents had been informed about overdiagnosis; opinions on informing people; and views about financial ties among panels writing disease definitions.Our sample was generally representative, but included a higher proportion of females and seniors, typical of similar surveys. American Association for Public Opinion Research response rate was 20% and cooperation rate was 44%. Only 10% (95% CI 8%-13%) of people reported ever being told about overdiagnosis by a doctor. 18% (95% CI 11%-28%) of men who reported having prostate cancer screening, and 10% (95% CI 6%-15%) of women who reported having mammography said they were told about overdiagnosis. 93% (95% CI 90%-95%) agreed along with screening benefits, people should be informed about overdiagnosis. On panels setting disease definitions, 78% (95% CI 74%-82%) felt ties to pharmaceutical companies inappropriate, and 91% (95% CI 82%-100%) believed panels should have a minority or no members with ties. Limitations included questionnaire novelty and complexity.A small minority of Australians surveyed, including those reporting being screened for prostate or breast cancer, reported being informed of overdiagnosis; most believed people should be informed; and a majority felt it inappropriate that doctors with ties to pharmaceutical companies write disease definitions. Results suggest strategies to better inform people about overdiagnosis, and review disease definition processes, have significant public sympathy
Maximizing Neumann fundamental tones of triangles
We prove sharp isoperimetric inequalities for Neumann eigenvalues of the
Laplacian on triangular domains.
The first nonzero Neumann eigenvalue is shown to be maximal for the
equilateral triangle among all triangles of given perimeter, and hence among
all triangles of given area. Similar results are proved for the harmonic and
arithmetic means of the first two nonzero eigenvalues
Specifying color differences in a linear color space (LEF)
This work presents a novel way of generating color differences for synthesizing artistically screened color images. A single color is specified by interacting with the mouse alternately on a constant luminance plane and on a constant hue plane within the LEF color space (the orthogonal space formed by the RGB cube's black-white axis (L) and by its E and F chrominance axes). By interactively selecting a second color point, a color difference is specified. We present a method for extrapolating this color difference throughout all colors of the RGB cube so as to generate consistent color differences, i.e. smoothly varying similar color differences for different colors. The produced artistically screened color patches show that significant luminance differences always generate significant visually perceived differences, whereas significant hue and/or saturation differences do not always generate significant visually perceived differences
An interface for the interactive design of artistic screens
The article presents the concepts and the tools involved in the interactive design of artistic screens. The screen elements are derived from a small set of analytical contours provided by the screen designer. We present the requirements that these contours must satisfy in order to generate consistent screens. Software tools have been developed which provide automatic means for verifying and enforcing these constraints. They include a way of specifying the periodicity of the screen dot and a graphical interface offering a convenient way of specifying and tuning the growth of the screen do
Legibility of perceptually-tuned grayscale fonts
Perceptually-tuned grayscale fonts are generated from character outline descriptions by applying to them a set of modifications specifically conceived for strengthening thin character parts, obtaining well-contrasted bars and preserving important relationships between character shape parts. The present study aims at comparing the legibility of perceptually-tuned grayscale and bilevel display fonts at small and very small sizes (6, 8 and 10 pt) The study confirms the results of previous studies indicating that reading speed is to a large extent independent of the typography (bilevel or grayscale) and the font size. However, perceptually-tuned grayscale characters perform better than bilevel characters for an italic string search task in a meaningless text. Regarding the subjective preferences of the test subjects, perceptually-tuned grayscale fonts at 8 and 10 point sizes received a superior rating than bilevel fonts at the same size
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