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 1,675 records · Page 93Linked to original sources

Geographical Information Systems risk assessment models for zoonotic fascioliasis in the South American Andes region.

The WHO recognises Fasciola hepatica to be an important human health problem. The Andean countries of Peru, Bolivia and Chile are those most severely affected by this distomatosis, though areas of Ecuador, Colombia and Venezuela are also affected. As part of a multidisciplinary project, we present results of use of a Geographical Information Systems (GIS) forecast model to conduct an epidemiological analysis of human and animal fasciolosis in the central part of the Andes mountains. The GIS approach enabled us to develop a spatial and temporal epidemiological model to map the disease in the areas studied and to classify transmission risk into low, moderate and high risk areas so that areas requiring the implementation of control activities can be identified. Current results are available on a local scale for: (1) the northern Bolivian Altiplano, (2) Puno in the Peruvian Altiplano, (3) the Cajamarca and Mantaro Peruvian valleys, and (4) the Ecuadorian provinces of Azuay, Cotopaxi and Imbabura. Analysis of results demonstrated the validity of a forecast model that combines use of climatic data to calculate of forecast indices with remote sensing data, through the classification of Normalized Difference Vegetation Index (NDVI) maps.

Altitude↗

Predicting AIDS deaths and prevalence in Australia.

OBJECTIVE: To describe a method for predicting deaths from, and the prevalence of, the acquired immunodeficiency syndrome (AIDS) in Australia and to obtain ranges of projections for the next five years based on data observed to 30 September 1989 and reported by January 1990. The projections are important components of planning for future health-care needs. PATIENTS: All patients with AIDS in Australia who were known to the National Centre in HIV Epidemiology and Clinical Research. The data used in the analysis were date of diagnosis of AIDS, date of death if the patient had died, and State or Territory of diagnosis. RESULTS: For Australia as a whole, the doubling time of AIDS incidence changed from 0.83 years before mid 1987 to 4.34 years after that time. Five hundred and seventy patients were diagnosed with AIDS to 30 June 1987 of whom 487 had died by 30 September 1989 and the estimated mean survival time was 1.36 years. Of 1037 patients diagnosed with AIDS after June 1987, 352 had died and the estimated mean survival time was 2.42 years. Combining the estimated survival distribution with the projected new cases of AIDS, we forecast that there will be between 530 and 680 deaths from AIDS in Australia in the year mid 1991 to mid 1992. Estimated cumulative deaths to mid 1994 range from 3390 to 4250. We predict that there will be between 1370 and 1850 people living with AIDS during the year ending mid 1992, and that this number will increase to between 1760 and 2830 for the year ending mid 1994. We also predict that the prevalence of AIDS in New South Wales will lie between 820 and 1620 for the year ending mid 1994, and that the prevalence in Victoria will lie between 270 and 740 in the same year. CONCLUSIONS: Any value in the range of predictions for AIDS incidence we give is equally likely and there is good agreement with the data now observed from mid 1989 to mid 1990. The dramatic increase in the doubling time is the result of a number of factors predicted by epidemic theory and the availability of treatment, zidovudine in particular. Our estimates of deaths and prevalence have been influenced by the quality of the available death data. The observed number of deaths in the year mid 1989 to mid 1990 has exceeded the number forecast for that year. Substantial improvements in survival were associated with the introduction of zidovudine into clinical practice in mid 1987 but the death rate has risen rapidly again in the very recent past, possibly due to patients becoming increasingly refractory to treatment with zidovudine (before or after a diagnosis of AIDS). Our approach to forecasting can be adjusted to accommodate a transient effect of treatment as further data accumulate.

Acquired Immunodeficiency Syndrome↗

Quercus pollen season dynamics in the Iberian peninsula: response to meteorological parameters and possible consequences of climate change.

The main characteristics of the Quercus pollination season were studied in 14 different localities of the Iberian Peninsula from 1992-2004. Results show that Quercus flowering season has tended to start earlier in recent years, probably due to the increased temperatures in the pre-flowering period, detected at study sites over the second half of the 20th century. A Growing Degree Days forecasting model was used, together with future meteorological data forecast using the Regional Climate Model developed by the Hadley Meteorological Centre, in order to determine the expected advance in the start of Quercus pollination in future years. At each study site, airborne pollen curves presented a similar pattern in all study years, with different peaks over the season attributable in many cases to the presence of several species. High pollen concentrations were recorded, particularly at Mediterranean sites. This study also proposes forecasting models to predict both daily pollen values and annual pollen emission. All models were externally validated using data for 2001 and 2004, with acceptable results. Finally, the impact of the highly-likely climate change on Iberian Quercus pollen concentration values was studied by applying RCM meteorological data for different future years, 2025, 2050, 2075 and 2099. Results indicate that under a doubled CO(2) scenario at the end of the 21st century Quercus pollination season could start on average one month earlier and airborne pollen concentrations will increase by 50 % with respect to current levels, with higher values in Mediterranean inland areas.

Air Pollutants↗

The benefits of treating hyperlipidemia to prevent coronary heart disease. Estimating changes in life expectancy and morbidity.

OBJECTIVE: To evaluate the lifetime benefits of reducing total serum cholesterol levels to prevent coronary heart disease (CHD). DESIGN: We developed a CHD primary prevention computer model to estimate the benefits associated with lifelong risk factor modification. We validated the model by comparing the computer estimates with the observed results of three primary CHD prevention trials. PATIENTS: Men and women age 35 to 65 years who are free of CHD, with total serum cholesterol levels ranging from 5.2 to 7.8 mmol/L (200 to 300 mg/dL), with or without additional CHD risk factors. INTERVENTIONS: Serum cholesterol reduction through dietary modification or diet and medications. MAIN OUTCOME MEASURES: Changes in life expectancy and the delay of symptomatic CHD. RESULTS: The computer forecasts for CHD end points closely matched the observed results of the Lipid Research Clinics Trial, the Helsinki Heart Study, and MRFIT. We then applied the computer model to low-risk and high-risk men and women with total serum cholesterol levels between 5.2 and 7.8 mmol/L (200 and 300 mg/dL) and estimated that, after reducing serum cholesterol levels 5% to 33%, the average life expectancy would increase by 0.03 to 3.16 years. We also forecast that the average onset of symptomatic CHD would be delayed among these patient groups by 0.06 to 4.98 years. CONCLUSION: We conclude that this computer model accurately estimates the results of clinical trials and can be used to forecast the changes in life expectancy and morbidity (the development of CHD) associated with specific CHD risk reduction interventions. The wide variation surrounding these estimates underscores the need to better define which groups of individuals will gain the most from cholesterol reduction.

Adult↗

What evidence do we have to replace in-hospital implantable cardioverter defibrillator follow-up?

INTRODUCTION: Due to the increasing number of patients with an implantable cardioverter defibrillator (ICD), new options for ICD patient follow-up management are required. METHODS: Patients with ICD indication according to the guidelines received an ICD with Home Monitoring technology. The devices enabled the transmission of the relevant episode, therapy, and system integrity data. Patients were followed for 12 months with routine controls every 3 months. The physician analyzed the Home Monitoring data before the routine follow-up visit (FU) and gave a forecast on the necessity of the pending FU, which was compared with the evaluation after the FU. Based on the derived forecast reliability, a patient management scheme was developed and its impact on patient safety was assessed retrospectively. RESULTS: A total of 271 patients were enrolled (40 f, mean age 62+/-12 years, mean LVEF 39+/-15%, 65% ischemic heart disease, 20% cardiomyopathy) and followed for 339+/-109 days. Of 908 pairs of Home Monitoring data and FU data evaluation, 129 there were false negative results for 92 patients. Safety concerns from false negative forecasts can be minimized with a patient management scheme containing the following elements: 1) never skip the first routine FU; 2) never skip a routine FU for a patient having already shown pacing threshold problems; 3) perform FU following hospitalizations; 4) perform FU following episode detection by the ICD; and 5) perform a routine FU if the patient reports symptoms. The retrospective analysis showed, that if the patients had been managed using this scheme, 503 of 1079 routine FU could have been skipped with only one safety concern, a three month delay in the detection of silent paroxysmal atrial fibrillation in one patient. CONCLUSIONS: Home Monitoring in ICD therapy over 12 months is feasible. The data transmitted relevantly contribute to a remarkable reduction of follow-up burden and enable the individualization of routine follow-up.

Adult↗

Analysis of cedar pollen time series: no evidence of low-dimensional chaotic behavior.

Much of the current interest in pollen time series analysis is motivated by the possibility that pollen series arise from low-dimensional chaotic systems. If this is the case, short-range prediction using nonlinear modeling is justified and would produce high-quality forecasts that could be useful in providing pollen alerts to allergy sufferers. To date, contradictory reports about the characterization of the dynamics of pollen series can be found in the literature. Pollen series have been alternatively described as featuring and not featuring deterministic chaotic behavior. We showed that the choice of test for detection of deterministic chaos in pollen series is difficult because pollen series exhibit [see text] power spectra. This is a characteristic that is also produced by colored noise series, which mimic deterministic chaos in most tests. We proposed to apply the Ikeguchi-Aihara test to properly detect the presence of deterministic chaos in pollen series. We examined the dynamics of cedar (Cryptomeria japonica) hourly pollen series by means of the Ikeguchi-Aihara test and concluded that these pollen series cannot be described as low-dimensional deterministic chaos. Therefore, the application of low-dimensional chaotic deterministic models to the prediction of short-range pollen concentration will not result in high-accuracy pollen forecasts even though these models may provide useful forecasts for certain applications. We believe that our conclusion can be generalized to pollen series from other wind-pollinated plant species, as wind speed, the forcing parameter of the pollen emission and transport, is best described as a nondeterministic series that originates in the high dimensionality of the atmosphere.

Cryptomeria↗

Change in injuries associated with safety belt laws.

Statewide crash data bases from nine states were subjected to time series analyses to detect changes in injuries associated with onset of seat belt laws in the respective states. In each of 18 analyses involving drivers covered by the law observed casualties were below the number forecast on the basis of prior experience and assuming that no law had been enacted. In the case of others, not covered by the law, observed injuries were equally often above or below forecast. Relative to covered drivers not only were the numbers below forecast, but in 12 of the 18 instances there was a statistically significant indication of an abrupt decrease the month the law began.

Accidents, Traffic↗

Arcial growth with metallic implants in mandibular growth prediction.

The present investigation was undertaken to determine whether the Ricketts theory of arcial growth of the mandible can be put to practical use by the clinician to predict mandibular morphology. Eight subjects (six girls and two boys) were selected from the earliest implant samples at the Orthodontic Department of Emory University School of Dentistry. The initial cephalograms were coded and sent to Ricketts, and a 6-year manual growth forecast using the arcial method was requested. The final cephalograms were traced and compared. The three tracings (initial, prediction, and final) were superimposed over the metallic implants and presented on a case-by-case basis. The forecasts, in form, were clinically acceptable in five of the eight cases. In two of the cases (girls) (Cases 2 and 4) a hand-wrist radiograph to determine skeletal age would have improved their accuracy. The forecast in Case 2 was not acceptable. In view of our results in this small sample, the arcial method appears valid for prediction of amndibular growth; however, hand-wrist radiographs will improve the accuracy of short-range predictions of the amount of growth expected. For this reason, the orthodontist should constantly monitor his patients, watching for each individual to assert himself.

Adolescent↗

Bioprogressive therapy as an answer to orthodontic needs. Part II.

From the foregoing discussions, it may be recognized that a new, lighter, and sequential order of force applications is recommended. Accordingly, in order for the clinician to apply the new technique with the intelligence, he must realize that many biologic factors form the fundamental criteria of its application. We have attempted to examine these factors and place them in their appropriate hierarchy of significance. While edgewise was the background, sufficient departure from traditional edgewise therapy has been made to warrant a new label, ""bioprogressive therapy.'' It was so named because of the practice of progressive banding and a planned progression of events in sequential order. Eight steps usually form the frame of reference. Ironically, it can be applied in the very young and in the very old. It is difficult to appreciate these views and practices in the beginning because the method may be difficult to envision on the typodont or as simply a laboratory mechanical exercise due to the fact that cortical bone, growth, and muscle are not present in an artificial medium. In order to fully apply the recommendations of the proponents of this method, mechanical forecasting, physiologic forecasting, and growth forecasting principles are all employed. Even as a simple mechanical regime, however, it rates with or better than any other current multibanded method as a practical and efficient clinical procedure. Size 0.016 by 0.016 inch blue Elgiloy wire is commonly but not exclusively used. Loops or forms are bent in the wire for lighter and more continuous pressures on teeth to be moved. Soldering of auxiliaries has been eliminated, as well as the heat treating of wires. The 0.016 by 0.016 inch to 0.016 by 0.022 inch yellow Elgiloy is used for detailing near the end of treatment. The 0.018 by 0.022 inch is the largest wire employed, and it is used for spanning distances between teeth in the progressive debanding phases. Anchor teeth are stabilized against cortical bone; hence, cortical anchorage. In order to position and control the teeth behind or away from cortical bone or against or away from muscle or to intrude into or extrude away from the bony alveolus, three-plane control is utilized. A limited use of round wire is employed with this technique except for specific isolated conditions in which there is a place for tipping or simple alignment and rotation of teeth. We try to avoid leveling with round wires, for reasons that have been explained. Used as a triple-control technique, the bioprogressive method excels in proper overtreatment and for delivery of anchorage. A continuous arch is broken up into segments so that movements in desired planes of space are not complicated and anchorage can be shifted in favor of the desired move. The technique usually involves orthopedic correction, particularly in the maxilla, when such corrections are needed...

Biomechanical Phenomena↗

Three-year prospect of patients with common epithelial carcinoma of the ovary.

In order to forecast the survival of patients, we collected 417 cases of common epithelial carcinoma of the ovary as a population for this study, then selected 141 cases who had survived more than 3 years and 131 cases who had died within 3 years as a sample of statistical inference. The sample was computerized inputting 25 factors which were obtained mainly on the first surgery. We selected 8 factors with 46 items considering their weight to forecast the prognosis on convenience. The selection of factors was carried out by following three basic principles. First, we selected factors that retained high partial correlation coefficients. Second, we selected factors which did not overlap each other in their contents. Third, we selected factors which were not decided intentionally. Accordingly, the score for forecasting the 3-year survival of patients with ovarian carcinoma was framed. The correct discrimination rate of the score when it was judged at the 0 point was 86.8% in the sample group. However, in the sample group outside the population, it was 83.1%.

Adult↗

Solar flares: an overview.

This is a survey of solar phenomena and physical models that may be useful for improving forecasts of solar flares and proton storms in interplanetary space. Knowledge of the physical processes that accelerate protons has advanced because of gamma-ray and X-ray observations from the Solar Maximum Mission telescopes. Protons are accelerated at the onset of flares, but the duration of any subsequent proton storm at 1 AU depends on the structure of the interplanetary fields. X-ray images of the solar corona show possible fast proton escape paths. Magnetographs and high-resolution visible-band images show the magnetic field structure near the acceleration region and the heating effects of sunward-directed protons. Preflare magnetic field growth and shear may be the most important clues to the physical processes that generate high energy solar particles. Any dramatic improvement in flare forecasts will require high resolution solar telescopes in space. Several possibilities for improvements in the art of flare forecasting are presented, among them: the use of acoustic tomography to probe for subsurface magnetic fields; a satellite-borne solar magnetograph; and an X-ray telescope to monitor the corona for eruptions.

Astronomical Phenomena↗

Childhood influences on youth obesity.

We develop a model to estimate the influence of child and parental characteristics on the likelihood that a child will become an obese or overweight youth. We use this model to test whether it is possible to forecast obesity and overweight among youth. Comparing Receiver Operating Characteristic (ROC) scores from these forecasts, we find that a model using childhood covariates does as well in forecasting youth obesity and overweight as a model using the covariate values contemporaneous with the youth obesity and overweight outcomes. The datasets used in this paper, the National Longitudinal Survey of Youth (NLSY79) and the NLSY79 Children and Young Adults, provide data from 1986 to 2002, allowing for the study of a child's transition to and from obesity or overweight over a long period. Explanatory variables that significantly influence the likelihood of youth obesity or overweight outcomes include the mother's obesity status and education, the youth's mental health, and certain demographic features including race, sex, and family size. These factors provide potential targets for policies that could be implemented early in life among children most likely to become obese or overweight.

Adolescent↗

The therapeutic antibodies market to 2008.

The therapeutic biologics market is currently dominated by recombinant protein products. However, many of these products are mature, and growth of the biologics market will increasingly rely on the expansion of the therapeutic monoclonal antibody sector. Successive technology waves have driven the growth of the monoclonal antibody sector, which is currently dominated by chimeric antibodies. Chimeric products, led by Remicade and Rituxan, will continue to drive market share through to 2008. However, over the forecast period, humanized and fully human monoclonal antibodies, together with technologies such as Fabs and conjugated antibodies, will play an increasingly important role, driving monoclonal antibody market growth at a forecast compound annual growth rate of 20.9%, to reach $16.7 billion by 2008. In terms of therapeutic focus, the monoclonal antibody market is heavily focused on oncology and arthritis, immune and inflammatory disorders, and products within these therapeutic areas are set to continue to be the key growth drivers over the forecast period. Underlying the growth of the market is the evolution of the monoclonal antibody company business model, set to transition towards the highly successful innovator model.

Animals↗

A software tool to aid long-term care budget planning at local authority level.

OBJECTIVE: Local authorities face real challenges when it comes to annual budget planning for funding the system of long-term care. Uncertainty about the long-term cost of caring for current residents in the system, in addition to unknown future admissions, have made the tasks of local authority budget managers very complex and demanding. In this paper, we present a software implementation of a novel forecasting framework developed by the authors to provide useful information to local authority budget planners involved in long-term care. METHODS: The tool is built upon a forecasting framework, which combines unit costs of care with an estimated underlying survival model for publicly funded residents in long-term care, to provide forecasts of the cost of maintaining the group of elderly people who are currently in long-term care (referred to as known commitments) for a period of time. A prototype version of the software tool, which was created and tested in collaboration with an English borough, allows user interaction via a friendly graphical interface that guides through a set of screens of options in a familiar wizard fashion. RESULTS AND DISCUSSION: Feedback from care planners and managers show that the tool helps them gain better understanding of the patterns of length-of-stay of residents under their care, and provides quantitative inputs into their decision making on budget planning for long-term care. The development of the software tool brings advanced modelling techniques out of research papers into the hands of decision makers in the public sector and contributes to improving the delivery of long-term care.

Activities of Daily Living↗

Radionuclide migration in forest ecosystems--results of a model validation study.

The primary objective of the IAEA's BIOMASS Forest Working Group (FWG) was to bring together experimental radioecologists and modellers to facilitate the exchange of information which could be used to improve our ability to understand and forecast radionuclide transfers within forests. This paper describes a blind model validation exercise which was conducted by the FWG to test nine models which members of the group had developed in response to the need to predict the fate of radiocaesium in forests in Europe after the Chernobyl accident. The outcomes and conclusions of this exercise are summarised. It was concluded that, as a group, the models are capable of providing an envelope of predictions which can be expected to enclose experimental data for radiocaesium contamination in forests over the time scale tested. However, the models are subject to varying degrees of conceptual uncertainty which gives rise to a very high degree of divergence between individual model predictions, particularly when forecasting edible mushroom contamination. Furthermore, the forecasting capability of the models over future decades currently remains untested.

Ecosystem↗

Sea surface temperature 1871-2099 in 14 cells around the United Kingdom.

Monthly sea surface temperature is provided for 14 locations around the UK for a 230 year period. These series are derived from the HadISST1 data set for historical time (1871-1999) and from the HadCM3 climate model for predicted SST (1950-2099). Two adjustments of the forecast data sets are needed to produce confluent SST series: the 50 year overlap is used for a gross adjustment, and a statistical scaling on the forecast data ensures that annual variations in forecast data match those of historical data. These monthly SST series are available on request. The overall rise in SST over time is clear for all sites, commencing in the last quarter of the 20th century. Apart from expected trends of overall warmer mean SST with more southerly latitudes and overall cooler mean SST towards the East, more interesting statistically significant general trends include a greater decadal rate of rise from warmer starting conditions. Annual temperature variation is not affected by absolute temperature, but is markedly greater towards the East. There is no correlation of annual range of SST with latitude, or with present SST values.

Atlantic Ocean↗

Do the benefits of finasteride outweigh the risks in the prostate cancer prevention trial?

PURPOSE: The Prostate Cancer Prevention Trial demonstrated that finasteride could reduce the incidence of prostate cancer by 25%. However, its use was also associated with an increased risk of high grade cancer resulting in uncertainty surrounding the net benefits of therapy. MATERIALS AND METHODS: We used the Montreal Prostate Cancer Model, a validated Markov model of prostate cancer progression, to compare the forecasted survival in treated and untreated men. The conditions of the model were varied to reflect different assumptions about whether the cancer grade difference observed in the PCPT was real or a treatment associated artifact, and whether cancers detected on end of study biopsies were clinically significant. RESULTS: For a hypothetical cohort of 1,000, 62-year-old men treated with finasteride, an increased survival of 140 life-years (0.14 years per individual) is forecasted if all diagnosed cancers are considered. If tumor grade differences are held to be artifactual, the forecasted benefits increase to 200 life-years. However, if the tumor grade difference is real and only clinically detected cancers are considered, estimated increased survival is only 20 life-years (0.02 years per individual). CONCLUSIONS: The primary prevention of prostate cancer with finasteride looks promising. However, at the present time it should only be considered with caution until we have answered critical questions surrounding the difference in cancer grade observed in the PCPT and the clinical significance of cancers detected on protocol directed end of study biopsies.

Aged↗

Incidence of lip cancer in the male Norwegian agricultural population.

OBJECTIVE: To explore lip cancer (LC) associations with work environmental exposures in a record-linkage study of Norwegian farmers. We hypothesize immunosuppressive substances (e.g. mycotoxins, pesticides) to influence LC incidence. METHODS: A cohort of 131,243 male Norwegian farmers born 1925-1971 was established by cross-linkage of national registers and followed up through 1999 for incident LC, (ICD-7 site 140) in the Cancer Registry of Norway. Farm production data from agricultural censuses 1969-1979 and meteorological data on solar radiation and fungal forecasts (events of wet and temperate conditions known to favour fungal growth and mycotoxin formation) served as exposure proxies. Adjusted rate ratios (RR) and 95% confidence intervals (CI) were estimated using Poisson regression. RESULTS: We identified 108 LC cases (rate 4.4 per 100,000 person-years). We found LC to be moderately associated with horses on the farm (RR = 1.6, CI = 1.0-2.4), construction work employment (RR = 1.7, CI = 1.1-2.6), pesticide use (RR = 0.7, CI = 0.4-1.0), grain production (RR = 1.3, CI = 0.9-2.1) and increasing levels of fungal forecasts (RR = 1.6, CI = 0.9-2.8 in the highest two quartiles). CONCLUSION: Moderate associations of LC with grain production and fungal forecasts and the negative association with pesticide could possibly be explained by exposure to immunosuppressive mycotoxins. Some of the associations observed could be explained by solar exposure.

Adult↗