Search results for "US POPULATION"
showing 10 items of 10 documents
Opinion Dynamics and Stubbornness via Multi-Population Mean-Field Games
2016
This paper studies opinion dynamics for a set of heterogeneous populations of individuals pursuing two conflicting goals: to seek consensus and to be coherent with their initial opinions. The multi-population game under investigation is characterized by (i) rational agents who behave strategically, (ii) heterogeneous populations, and (iii) opinions evolving in response to local interactions. The main contribution of this paper is to encompass all of these aspects under the unified framework of mean-field game theory. We show that, assuming initial Gaussian density functions and affine control policies, the Fokker---Planck---Kolmogorov equation preserves Gaussianity over time. This fact is t…
Aggregate Behavior and Microdata
2004
Abstract It is shown how one can effectively use microdata in modelling the change over time in an aggregate (e.g. mean consumption expenditure) of a large and heterogeneous population. The starting point of our aggregation analysis is a specification of explanatory variables on the micro-level. Typically, some of these explanatory variables are observable and others are unobservable. Based on certain hypotheses on the evolution over time of the joint distributions across the population of these explanatory variables we derive a decomposition of the change in the aggregate which allows a partial analysis: to isolate and to quantify the effect of a change in the observable explanatory variab…
Homing and memory patterns of human gammadelta T cells in physiopathological situations.
2004
Vgamma9Vdelta2 are a heterogeneous population of T cells and comprise distinct naive, memory and effector populations that can be distinguished on the basis of surface marker expression and effector functions. We review here these recently studied features of Vgamma9Vdelta2 T lymphocyte biology and the roles they play in infectious and autoimmune diseases.
Effects of diabetes definition on global surveillance of diabetes prevalence and diagnosis: a pooled analysis of 96 population-based studies with 331…
2015
Diabetes has been defined on the basis of different biomarkers, including fasting plasma glucose (FPG), 2-h plasma glucose in an oral glucose tolerance test (2hOGTT), and HbA1c. We assessed the effect of different diagnostic definitions on both the population prevalence of diabetes and the classification of previously undiagnosed individuals as having diabetes versus not having diabetes in a pooled analysis of data from population-based health examination surveys in different regions.
A practical approach with outcome for the prognostic assessment of non-ST-segment elevation chest pain and normal troponin.
2007
Patients with non-ST-elevation chest pain constitute a heterogeneous population. Our aim is to compare the outcome of patients with chest pain, non-ST-segment deviation, and normal troponin, categorized using a risk score, with that of patients with ST depression or troponin increase. A total of 1,449 patients with non-ST-elevation chest pain were evaluated. A validated risk score (using pain characteristics and risk factors) was applied to patients without ST depression or troponin increase. Accordingly, 4 risk categories were defined: group 1, no troponin increase, no ST depression, and risk score3 points (n = 633); group 2, no troponin increase, no ST depression, but risk scoreor = 3 poi…
Functional nicotinic acetylcholine receptors on subplate neurons in neonatal rat somatosensory cortex.
2004
The establishment of cortical synaptic circuits during early development requires the presence of subplate neurons (SPn's), a heterogeneous population of neurons capable to integrate and process synaptic information from the thalamus, cortical plate, and neighboring SPn's. An accumulation of cholinergic afferents and nicotinic acetylcholine receptors (nAChRs) has been documentated in the subplate around birth. To assess the developmental role of the cholinergic innervation onto SPn's, we used whole cell patch-clamp recordings of visually identified and biocytin-labeled SPn's in neonatal rat somatosensory cortex. Functional nAChRs were present in 92% of the investigated SPn's. Activation of…
Urinary Arsenic Species and Methylation Efficiency During Pregnancy: Concentrations and Associated Factors in Spanish Pregnant Women
2021
Background: Arsenic (As) is considered to be toxic for humans, the main routes of exposure being through drinking water and the diet. Once ingested, inorganic arsenic can be methylated sequentially to monomethyl and dimethyl arsenicals. Several factors can affect both As exposure and methylation efficiency. Objectives: To describe the urinary concentrations of the different As species and evaluate the methylation effi-ciency during pregnancy, as well as their associated factors in a birth cohort of pregnant Spanish women. Methods: Participants in this cross-sectional study were 1017 pregnant women from two areas of Spain who had taken part in the INMA (Environment and Childhood) project (20…
Nondestructive Direct Determination of Heroin in Seized Illicit Street Drugs by Diffuse Reflectance near-Infrared Spectroscopy
2008
A new method has been developed for the fast and nondestructive direct determination of heroin in seized street illicit drugs using partial least-squares regression analysis of diffuse reflectance near-infrared spectra. Data were obtained from untreated samples placed in standard glass chromatography vials. A heterogeneous population of 31 samples, previously analyzed by a reference method, was employed to build the calibration model and to have a separated validation set. Based on the use of zero-order data for a calibration set of 21 samples, after standard normal variate and quadratic linear removed baseline correction (detrending), in the wavelength range from 1111 to 1647 nm, 8 PLS fac…
Identification of Replicator Mutator models
2006
The complexity of biology literally calls for quantitative tools in order to support and validate biologists intuition and traditional qualitative descriptions. In this paper, the Replicator-Mutator models for Evolutionary Dynamics are validated/invalidated in a worst-case deterministic setting. These models analyze the DNA and RNA evolution or describe the population dynamics of viruses and bacteria. We identify the Fitness and the Replication Probability parameters of a genetic sequences, subject to a set of stringent constraints to have physical meaning and to guarantee positiveness. The conditional central estimate is determined in order to validate/invalidate the model. The effectivene…
Multilevel Latent Profile Analysis With Covariates : Identifying Job Characteristics Profiles in Hierarchical Data as an Example
2018
Latent profile analysis (LPA) is a person-centered method commonly used in organizational research to identify homogeneous subpopulations of employees within a heterogeneous population. However, in the case of nested data structures, such as employees nested in work departments, multilevel techniques are needed. Multilevel LPA (MLPA) enables adequate modeling of subpopulations in hierarchical data sets. MLPA enables investigation of variability in the proportions of Level 1 profiles across Level 2 units, and of Level 2 latent classes based on the proportions of Level 1 latent profiles and Level 1 ratings, and the extent to which covariates drawn from the different hierarchical levels of th…