Prediction of activity related energy expenditure using accelerometer derived physical activity under free-living conditions-a systematic review

BACKGROUND: Activity related energy expenditure (AEE) might be an important factor in the etiology of chronic diseases. However, measurement of free-living AEE is usually not feasible in large scale epidemiological studies but instead has traditionally been estimated based on self-reported physical activity. Recently, accelerometry has been proposed for objective assessment of physical activity, but it is unclear to what extent this methods explains the variance in AEE. METHODS: We conducted a systematic review searching MEDLINE database (until 2014) on studies that estimated AEE based on accelerometry-assessed physical activity in adults under free-living conditions (using doubly-labeled water method). Extracted study characteristics: sample size, accelerometer (type [uniaxial, triaxial], metrics [e.g. activity counts, steps, acceleration], recording period, body position, wear time), explained variance of AEE (R2), number of additional predictors. The relation of univariate and multivariate R2 with study characteristics was analyzed using non-parametric tests. RESULTS: Nineteen articles were identified. Examination of various accelerometers or subpopulations in one article was treated separately, resulting in 28 studies. Sample sizes ranged from 10-149. In most studies the accelerometer was triaxial, worn at the trunk, during waking hours, and reported activity counts as output metric. Recording periods ranged from 5-15 days. The variance of AEE explained by accelerometer assessed physical activity ranged from 4-80% (median crude R2=26%). Sample size was inversely related to the explained variance. Inclusion of 1 to 3 other predictors in addition to accelerometer output significantly increased the explained variance to a range of 12.5-86% (median total R2=41%). The increase did not depend on the number of added predictors. CONCLUSIONS: We conclude that there is large heterogeneity across studies in the explained variance of AEE when estimated based on accelerometry. Thus, data on predicted AEE based on accelerometry assessed physical activity need to be interpreted cautiously

Association of body surface scanner-based abdominal volume with parameters of the Metabolic Syndrome and comparison with manually measured waist circumference

To investigate abdominal volume determined by a new body scanner algorithm as anthropometric marker for Metabolic Syndrome (MetS) and its parameters compared to manually measured waist circumference (WC), we performed body scans in 411 participants (38% men, 20-81 years). WC and triglyceride, HDL-cholesterol, and fasting glucose concentrations, and blood pressure were assessed as MetS parameters. We used Spearman correlations and linear regression to investigate associations and goodness-of-fit (R(2), BIC) of abdominal volume and WC with MetS parameters, and logistic regression to analyse the discriminative power of WC and abdominal volume to assess likelihoods of MetS components and MetS. Correlations with triglyceride, HDL-cholesterol, and glucose concentration were slightly stronger for abdominal volume (r; 0.32, −0.32, and 0.34, respectively) than for WC (0.28, −0.28, and 0.29, respectively). Explained variances in MetS parameters were slightly higher and goodness-of-fit slightly better for abdominal volume than for WC, but differences were small. Exemplarily, glucose levels were 0.28 mmol/L higher (R² = 0.25; BIC = 945.5) per 1-SD higher WC, and 0.35 mmol/L higher (R² = 0.28; BIC = 929.1) per 1-SD higher abdominal volume. The discriminative power to estimate MetS components was similar for WC and abdominal volume. Our data show that abdominal volume allows metabolic characterization comparable to established WC

Validity and reliability of total body volume and relative body fat mass from a 3-dimensional photonic body surface scanner

OBJECTIVE: Three-dimensional photonic body surface scanners (3DPS) feature a tool to estimate total body volume (BV) from 3D images of the human body, from which the relative body fat mass (%BF) can be calculated. However, information on validity and reliability of these measurements for application in epidemiological studies is limited. METHODS: Validity was assessed among 32 participants (men, 50%) aged 20-58 years. BV and %BF were assessed using a 3DPS (VitusSmart XXL) and air displacement plethysmography (ADP) with a BOD POD(R) device using equations by Siri and Brozek. Three scans were obtained per participant (standard, relaxed, exhaled scan). Validity was evaluated based on the agreement of 3DPS with ADP using Bland Altman plots, correlation analysis and Wilcoxon signed ranks test for paired samples. Reliability was investigated in a separate sample of 18 participants (men, 67%) aged 25-66 years using intraclass correlation coefficients (ICC) based on two repeated 3DPS measurements four weeks apart. RESULTS: Mean BV and %BF were higher using 3DPS compared to ADP, (3DPS-ADP BV difference 1.1 +/- 0.9 L, p<0.01; %BF difference 7.0 +/- 5.6, p<0.01), yet the disagreement was not associated with gender, age or body mass index (BMI). Reliability was excellent for 3DPS BV (ICC, 0.998) and good for 3DPS %BF (ICC, 0.982). Results were similar for the standard scan and the relaxed scan but somewhat weaker for the exhaled scan. CONCLUSIONS: Although BV and %BF are higher than ADP measurements, our data indicate good validity and reliability for an application of 3DPS in epidemiological studies

Dynamic Visual Abstraction of Soccer Movement

Trajectory-based visualization of coordinated movement data within a bounded area, such as player and ball movement within a soccer pitch, can easily result in visual crossings, overplotting, and clutter. Trajectory abstraction can help to cope with these issues, but it is a challenging problem to select the right level of abstraction (LoA) for a given data set and analysis task. We present a novel dynamic approach that combines trajectory simplification and clustering techniques with the goal to support interpretation and understanding of movement patterns. Our technique provides smooth transitions between different abstraction types that can be computed dynamically and on-the-fly. This enables the analyst to effectively navigate and explore the space of possible abstractions in large trajectory data sets. Additionally, we provide a proof of concept for supporting the analyst in determining the LoA semi-automatically with a recommender system. Our approach is illustrated and evaluated by case studies, quantitative measures, and expert feedback. We further demonstrate that it allows analysts to solve a variety of analysis tasks in the domain of soccer

Conserved Charge Fluctuations from Lattice QCD and the Beam Energy Scan

We discuss the next-to-leading order Taylor expansion of ratios of cumulants of net-baryon number fluctuations. We focus on the relation between the skewness ratio, $S_B\sigma_B = \chi_3^B/\chi_1^B$, and the kurtosis ratio, $\kappa_B\sigma_B^2 =\chi_4^B/\chi_2^B$. We show that differences in these two cumulant ratios are small for small values of the baryon chemical potential. The next-to-leading order correction to $\kappa_B\sigma_B^2$ however is approximately three times larger than that for $S_B\sigma_B$. The former thus drops much more rapidly with increasing beam energy, $\sqrt{s_{NN}}$. We argue that these generic patterns are consistent with current data on cumulants of net-proton number fluctuations measured by the STAR Collaboration at $\sqrt{s_{NN}}\ge 19.6$~GeV.Comment: 4 pages, 4 figures, contribution to the Quark Matter 2015 proceeding

Electronic Instrumentation

Contains research objectives and reports on four research projects.Electronic Instrumentation Group of the Research Laboratory of Electronics in research under NIH Grant 1 505 FR07047-01National Institutes of Health (Grant 1 505 FR07047-01

Mixed couples in France. Statistical facts, definitions, and social reality

Mixed couples are usually defined as combining national, cultural, racial or religious dif­ferences, but these definitions are generally elaborated only empirically. More recently, researchers have proposed the concept of "mixedness" which goes beyond those descriptive factors of difference. The French national Migration, Tradition and Citizenship Act also helps to show why it is not easy to reach a single definition.A detailed look at statistical realities illustrates how complex it is to count mixed cou­ples. The figures differ if we consider mixed marriages as flows (new marriages each year) or as stock (how many people live in a mixed family). They also vary depending on what differences —cultural belonging or nationality— are taken into account. Many French-foreign marriages bring together people who have the same cultural identities. From the sociological point of view, mixed marriage should be defined as combining perceived differences and existing social order and norms. Studies on mixedness look at how socially constructed differences in contact, e.g. in private life, influence social relations and modify social realities. Mixed couples experience specific social constraints due to the migration situation of at least one of the partners, and therefore these couples need time to learn to manage the cultural and social differences in their relationship. Differences between the partners due to their cultural and social affiliations or gender roles are not equal and also influence the transcultural hybridisation process, sometimes even hindering it considerably.Una pareja mixta se define generalmente como la combinación de las diferencias nacio­nales, culturales, raciales o religiosas. Pero estas definiciones generalmente se elaboran sólo empíricamente. Más recientemente, los investigadores han propuesto el concepto de «mestizaje», que va más allá de los factores descriptivos de la diferencia. La tradición de migración nacional francesa y la Ley de ciudadanía también ayudan a entender por qué no es fácil llegar a una definición única. Una mirada pormenorizada a la realidad estadística ilustra lo complejo que es contar el número de parejas mixtas. Las cifras difieren si se considera el matrimonio mixto como un flujo (los matrimonios nuevos cada año) o como población (número de personas que viven en una familia mixta). También varían en función de qué diferencias se tienen en cuenta —la pertenencia cultural o la nacionalidad. Muchos matrimonios entre franceses y extranjeros unen a personas que tienen la misma identidad cultural. Desde el punto de vista sociológico, el matrimonio mixto debería definirse como la combinación de las diferencias percibidas y el orden social existente y las normas. Los estu­dios sobre el mestizaje tratan de cómo las diferencias sociales en contacto -por ejemplo en la vida privada- influyen en las relaciones sociales y modifican la realidad social. Las parejas mixtas están involucradas en determinadas limitaciones sociales debido a la situación de migrante de por lo menos uno de los cónyuges. Por lo tanto, estas parejas necesitan tiempo para aprender a gestionar las diferencias culturales y sociales en su relación. Las diferencias entre los cónyuges, debidas a sus filiaciones sociales y culturales y a los roles de género, no están en pie de igualdad y también influyen en el proceso de hibridación transcultural, a veces incluso obstaculizándolo considerablemente

Solid-State Microwave Electronics

Contains reports on six research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300California Institute of Technology Contract 952568National Institutes of Health (Grant RR00317) from the Biotechnology Resources Branch, Division of Research Resource