PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “forecasting”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed1994

Non-linear forecasting measurements of multichannel EEG dynamics.

This work presents a new method for studying the underlying dynamics of multichannel EEG on the basis of the mathematical theory of dynamical systems. It computes the local loss of predictability and Kolmogorov entropy of the dynamics reconstructed from brain electrical activity. This reconstruction uses multichannel recordings in order to quantify an equivalent of spatio-temporal mapping. Five experimental conditions have been studied: closed eyes at rest, closed eyes and counting even numbers, staring at a spotlight, passive and active auditive odd-ball tasks. The entropy is positive for all the experimental conditions which proves that the underlying EEG dynamics are chaotic. Moreover, on the basis of the dynamical signature it is possible to differentiate 3 types of EEG activity: the rest closed eyes activity, the task closed eyes activity (counting and odd-ball tasks) and the open eyes activity (staring at a spotlight). It is inferred that this index could characterize task-related changes in brain activity.

Adult↗
PubMed1983

Forecast of cadmium impact on the environment using environmental models.

A study of the pathway of cadmium in the European Community (EC) has led to the development of a time-dependent computer model that relates past and present environmental cadmium levels to the inputs of cadmium. Information on the origin and movement of environmental cadmium through the different compartments of the biosphere has been obtained from a literature study and has been used to simulate the pathway of cadmium in the EC. The model is used to investigate the future evolution of the average cadmium concentrations in air, soil, and sediments in the EC, based on assumptions for the future evolution of consumption and for possible environmental policies to be adopted. The results are averages taken over the whole Community, which implies that no local pollution can be obtained from this model that only indicates the possible future trend.

Cadmium↗
PubMed1983

Adsorption, percolation, and decomposition methods for forecasting the behavior of organic chemicals in soils.

Sorption, movement, and decomposition of trichlorphenoxyacetic acid (2,4,5-T) in two Berlin soils were investigated in field experiments in summer and winter time. Contemporary with simple laboratory methods, it was attempted to predict the behavior under field conditions. For this purpose, adsorption and desorption experiments were carried out and isotherms were calculated using the Freundlich equation. Second, percolation studies under saturated and unsaturated conditions were considered. Finally, the decomposition of 2,4,5-T in soil samples at different temperature was determined. A sorption experiment at the beginning of a test program for prediction the behavior from chemical compounds at least with four soil samples, a Chernozem-Ah, a Cambisol-Ap, a Podsol Ah, and a Pelosol-B, completed by decomposition experiments measuring the CO2-respiration, is proposed.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1997

Spike train patterning and forecastability.

Theories of neural coding rely on a knowledge of correlations between firing events. These correlations are also useful to validate biophysical models for the neural activity. We present a methodology for validating models based on the assessment of linear and non-linear correlations between variables derived from the spike train. The firing pattern of an electroreceptor is analyzed in this framework. We show that a purely stochastic model fails to capture the essential correlations between interspike intervals, even though it reproduces the interval histogram and certain spike train spectral features. However, a biophysical model, based on the Fitzhugh-Nagumo equations with noise, does exhibit many of the correlations seen in the data, including those between successive firing phases.

Action Potentials↗
PubMed2005

Can flowcytometric DNA studies forecast the prognosis of endometrial hyperplasia?

OBJECTIVES: The study is investigating the relation of the ploidy pattern and cell cycle kinetics to different types of endometrial hyperplasia to select the high-risk women who will need strict follow up surveillance. STUDY DESIGN: An observational study of 152 patients with endometrial hyperplasia. Endometrial samples were subjected to flowcytometric study of the nuclear DNA content to determine the ploidy pattern and cell cycle kinetics. RESULTS: The mean age of women was 46.3+/-3.6 years. 15.8% of women were nulliparae, 36.8% were diabetic and 43.6% were hypertensive. 48.7% of women were obese (BMI>30). Most of endometrial samples (88.2%) were simple endometrial hyperplasia without atypia. The cell cycle kinetics in different types of endometrial hyperplasia shows that there were significant statistical differences as regards the S-phase fraction and proliferative index (PI) between typical and atypical hyperplasia. CONCLUSION: The study of cell cycle kinetics by flowcytometry might help in picking up, among all women with endometrial hyperplasia, the group of patients who need further close and strict follow up by endometrial pathologic study. This is going to minimize the cost and invasiveness of surveillance of patients with various grades of endometrial hyperplasia.

Adult↗
PubMed2006

SHP2 forecast for the immune system: fog gradually clearing.

The src homology 2 (SH2) domain containing tyrosine phosphatase SHP2 (also referred to as SHP-2) is ubiquitously expressed in mammalian tissues and has been shown to be essential for embryonic development, haematopoiesis and signalling downstream of a variety of growth factors. Dysregulation of SHP2 function or expression has recently been implicated in the pathogenesis of human diseases involving haematopoietic cell lineages. New findings also demonstrate the involvement of SHP2 in the regulation of immune responses through its effects on cytokine and inhibitory receptor signalling pathways, and novel transgenic models are providing valuable insights into the role of SHP2 in T cells.

Humans↗
PubMed2006

Behavioral trajectories as predictors in event history analysis: male calling behavior forecasts medfly longevity.

A recent study on wild male Mediterranean fruit flies [Papadopoulos, N.T., Katsoyannos, B.I., Kouloussis, N.A., Carey, J.R., Müller, H.-G., Zhang, Y., 2004. High sexual signalling rates of young individuals predict extended life span in male Mediterranean fruit flies. Oecologia 138, 127-134] provided evidence that intense sexual signalling (calling behavior) is associated with longer life span. We demonstrate here an approach based on functional data analysis methodology for predicting individual remaining longevity and the distribution of remaining lifetime from individual behavioral trajectories. A key methodological concept is the time evolution of mean functions and eigenfunctions. This methodology is applied to the event history of calling behavior of male medflies. The results demonstrate complex relationships between male calling behavior and subsequent longevity that complement previous biodemographic analyses of these data. A high level of recent calling activity is found to be associated with increased remaining lifetime for an individual male fly, while calling activity at early ages plays no role for remaining longevity.

Animals↗
PubMed2004

Protein C levels can be forecasted by global haemostatic tests in critically ill patients and predict long-term survival.

INTRODUCTION: We have shown the usefulness of global haemostatic tests International Normalized Ratio (INR) and Activated Partial Thromboplastin Time (APTT) for predicting survival in critically ill patients. Ability to analyse inhibitors protein C and antithrombin is limited to a small number of laboratories and often only during office hours. We therefore studied the usefulness of global haemostatic tests to predict levels of protein C and antithrombin and investigated value of these latter tests in predicting outcome. PATIENTS/METHODS: Blood samples were collected within 6 h of admission to intensive care unit (ICU) and tested regarding platelet count, INR, and APTT. If platelet count was <100x10(9) L(-1), INR >1.36 and/or APTT >45 s, a second sampling was done within 6 h after the first one for analysis of protein C and antithrombin. Ninety-two patients were included; length of stay at ICU and hospital, survival when leaving ICU and hospital and up to 5 years were recorded. RESULTS: Using univariate analysis of variance, INR and APTT separately predicted levels of protein C and to some extent antithrombin. Neither platelet count nor any combinations of global haemostatic tests were predictive. Utilising Cox regression, decreased protein C, but not antithrombin, predicted lower survival rate. CONCLUSIONS: Global haemostatic tests INR and APTT can predict levels of protein C and, though less so, antithrombin. A low protein C level indicated a sinister prognosis in the ICU setting, at the hospital, and after up to 5 years.

Aged↗
PubMed1998

Volatile halocarbons in a drinking water supply system: forecasting contamination values and estimating health risk.

The network, which supplies drinking water to the city of Milan, has a number of sampling points, where the concentrations of several contaminants are periodically measured. From the time series of total volatile halocarbon (VHC) concentration values (in the ppb range) autoregressive models can be obtained for each sampling point. A suitable figure of merit is minimized, which depends on the backcast error and on the model order. The best model is then applied to predicting concentration one time step e.g., one year, forward. The experimental data pertain to the years 1981 to 1992. Predicted values are compared with the measured ones. The results obtained in 1991 contributed to avert a major emergency situation in Milan. Population exposure and the related health risk, based on the proportional dosage-response model, were also estimated. The excess casualty figure for Milan was computed. The method and the procedures described herewith may be used by public authorities to manage drinking water resources, whenever detailed models of the aquifer and of the network are not applicable.

Environmental Monitoring↗