Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Area Analysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 163 records · Page 9Linked to original sources
PubMed2002

Physico-chemical characterisation of the inhalable particulate matter (PM10) in an urban area: an analysis of the seasonal trend.

Between October 1998 and February 2000, 11 particulate samplings were conducted in an urban area of Rome to evaluate the seasonal trend of PM10 characteristics: seven samplings were made at ground-level and four 30 m above ground level. The samples were analysed by scanning electron microscopy equipped with an EDS X-ray attachment and by transmission electron microscopy and an electron energy-loss spectrometer. The airborne particulate matter was characterised from a physico-chemical point of view to provide information on the particle composition and on the compounds carried on their surface. The data sets, consisting of the atomic concentrations of the constituent chemical elements of the fine (PM3.3) and of the coarse (PM10-3.3) particulate, were subjected to cluster analysis to determine the principal components of PM10. In the particulate matter, the statistical analysis methods allowed us to identify seven groups (clusters) of particles: C-rich particles; carbonates; silica; silicates; sulfates; Fe-rich particles; and metals. Carbonaceous and silicate particles with a surface coating containing S were observed. This sulfur-enriched coating turned out to be a PM3.3 feature strongly dependent upon season.

Air Pollutants↗
PubMed1988

Degree of malignancy of thymic epithelial tumors in terms of nuclear DNA content and nuclear area. An analysis of 39 cases.

For determination of the degree of malignancy among thymic epithelial tumors, the DNA content and area of nuclei in 13 cases each of noninvasive thymoma, invasive thymoma, and thymic carcinoma were investigated by cytofluorometry and morphometry. The nuclear DNA content was determined in terms of the mean nuclear DNA content, DNA histogram pattern, and the occurrence of the aneuploid stem cell line. The mean nuclear DNA content of the thymic carcinoma was significantly higher than that of both subgroups of thymoma (P less than 0.01), but there was no significant difference between noninvasive and invasive thymomas. The aneuploid stem cell line appeared in 92.3% of thymic carcinomas, one case (7.7%) of invasive thymomas, and none of noninvasive thymomas. Abnormal DNA histogram patterns were seen in 53.8% of thymic carcinomas and none of the thymomas. The mean nuclear area increased significantly in the increasing order of noninvasive thymoma, invasive thymoma, and thymic carcinoma (P less than 0.01). The cytofluorometric and morphometric results demonstrated a significant difference in degree of malignancy between thymic carcinoma and thymoma; however, there was a trend toward an increasing degree of malignancy from noninvasive to invasive thymomas, yet there was a sizeable overlap in results between the two groups. Therefore, these two methods are not satisfactory for predicting the behavior of an individual case of noninvasive or invasive thymoma.

Adult↗
PubMed2005

Childhood femur fractures, associated injuries, and sociodemographic risk factors: a population-based study.

OBJECTIVE: The objectives of this study were to determine the incidence of femur fractures in Colorado children, to assess underlying causes, to determine the prevalence and predictors of associated injuries, and to identify potentially modifiable risk factors. METHODS: The study population included all Colorado residents who were aged 0 to 17 years at the time of injury between January 1, 1998, and December 31, 2001. Cases of femur fracture were ascertained using the population-based Colorado Trauma Registry and International Classification of Diseases, Ninth Revision, Clinical Modification codes 820.0 to 821.39. Associated injuries with an Abbreviated Injury Scale of 2 or higher were classified into 5 categories. Poisson regression, small area analysis, and multivariate logistic regression were used to identify predictors of femur fractures and associated injuries, respectively. RESULTS: During the study period, 1139 Colorado children (795 boys, 344 girls) sustained femur fractures, resulting in the incidence of 26.0 per 100000 person-years. Rates were higher in boys than in girls in all age groups (overall risk ratio: 2.19; 95% confidence interval: 1.92-2.47) but did not differ by race/ethnicity. Femur fractures that were caused by nonaccidental trauma showed more distal and combined shaft + distal pattern; their incidence did not differ by gender or race but was higher in census tracts with more single mothers and less crowded households. Associated injuries were present in 28.6% of the cases, more often in older children. Fatalities occurred only among children with associated injuries. Children who were involved in nonaccidental trauma, motor vehicle crashes, or auto-pedestrian accidents were 16 to 20 times more likely to have associated injuries than those with femur fractures as a result of a fall. In small-area analysis, the incidence of femur fractures in infants and toddlers was higher in census tracts characterized by higher proportion of Hispanics, single mothers, and more crowded households. Among children 4 to 12 years of age, the incidence was higher in census tracts with fewer single-family houses and more crowded households. Finally, the incidence of femur fractures among teenagers was higher in rural tracts and those with a higher proportion of Hispanics. CONCLUSIONS: Femur fractures and associated injuries remain a major cause of morbidity in children. Predictors of femur fractures change with age; however, the risk is generally higher among children who live in the areas with lower socioeconomic indicators.

Abbreviated Injury Scale↗
PubMed1985

Possible windborne spread to western Turkey of bluetongue virus in 1977 and of Akabane virus in 1979.

An outbreak of bluetongue in sheep started in the Menderes valley, Aydin Province, Western Turkey, in October 1977. The severity of the disease indicated that it had not been there before but had been introduced into the area. Analysis showed that, while it was possible for the virus to have been brought into the area by movement of infected animals, there was also a period of south-easterly winds which could have carried infected midges from Cyprus, where bluetongue was present. During the night of 14-15 October 1977, south-easterly winds could have brought midges infected with bluetongue virus for the 15 h flight at a height possibly of 500 m and at temperatures of about 20 degrees C. A depression moving north-eastwards accompanied by rain may have affected the landing of midges in the Menderes valley on the morning of 15 October. An outbreak of arthrogryposis-hydranencephaly in newly born calves occurred in March-May 1980, also in the Menderes valley, Aydin Province. The severity of the outbreak indicated that Akabane virus had not been in the area before but had been introduced in September-November the previous year. While infected animals could have brought the virus into the area, analysis based on the probable time of infection of pregnant dams showed that easterly winds at the end of September or beginning of October 1979 could have brought insects infected with Akabane virus into the Menderes valley from eastern Turkey or northern Syria. These analyses illustrate the use of meteorological data to backtrack to possible sources and to identify the time of infection.

Air Movements↗
PubMed1994

Hurricane-related emergency department visits in an inland area: an analysis of the public health impact of Hurricane Hugo in North Carolina.

STUDY OBJECTIVE: To evaluate the public health impact of a hurricane on an inland area. DESIGN: Descriptive study. SETTING: Seven hospital emergency departments. PARTICIPANTS: Patients who were treated from September 22 to October 6, 1989, for an injury or illness related to Hurricane Hugo. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Over the two-week study period, 2,090 patients were treated for injuries or illnesses related to the hurricane. Of these, 1,833 (88%) were treated for injuries. Insect stings and wounds accounted for almost half of the total cases. A substantial proportion (26%) of the patients suffering from stings had a generalized reaction (eg, hives, wheezing, or both). Nearly one-third of the wounds were caused by chain saws. CONCLUSION: Hurricanes can lead to substantial morbidity in an inland area. Disaster plans should address risks associated with stinging insects and hazardous equipment and should address ways to improve case reporting.

Adolescent↗
PubMed2001

Relationship between socioeconomic factors and severe childhood injuries.

The objective was to examine the relationship between injury rates and socioeconomic factors for children in Hamilton County, Ohio, using small-area analysis. The subjects were county residents less than 15 years old who were hospitalized or died of injuries between January 1, 1993, and December 31, 1995; they were identified through a population-based trauma registry. The census tract was the unit of analysis; the rate of injury per 100,000 population was the dependent variable. Risk factors included median income, level of education, percentage below the poverty level, percentage unemployment, percentage non-Caucasian, and percentage families headed by females. There were 2,437 children meeting the case definition; injuries per census tract ranged from 0 to 2,020.2 per 100,000 per year. Census tracts with higher injury rates had lower median incomes, more people with less than a high school education, more unemployment, more families headed by females, more people living below the poverty level, and more non-Caucasians than those with lower rates. In a regression model, percentage of people living below the poverty level, percentage of those who did not graduate from high school, and percentage unemployment were significant risk factors for injuries, P < .001. Since small-area analysis examines associations on an ecological level rather than an individual level, these studies should always be interpreted with caution because an association found at the level of the census tract may not apply at the individual level. Interventions to reduce injuries should target socioeconomically disadvantaged children living below the poverty level and those in areas with fewer high school graduates and more unemployment.

Adolescent↗
PubMed1989

Cerebellar connections with the motor cortex and the arcuate premotor area: an analysis employing retrograde transneuronal transport of WGA-HRP.

We have employed transneuronal transport to examine the anatomical relationships between the deep cerebellar nuclei and 2 cortical motor areas: the primary motor cortex and the arcuate premotor area (APA). In the same animals, we have also examined the patterns of labeling in the thalamus and the red nucleus to provide evidence for the potential routes of transneuronal transport to the cerebellum. When the appropriate technical procedures were employed, cortical injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) resulted in transneuronal labeling within portions of the contralateral deep cerebellar nuclei. Injections into the primary motor cortex labeled neurons in the dentate and in the 2 subdivisions of the interpositus. Injections into the APA labeled neurons in the dentate and in only the posterior subdivision of the interpositus. In most instances, dentate neurons were more intensely labeled following the cortical injections than interpositus neurons. The transneuronal labeling observed in the dentate nucleus was topographically organized. The dentate region that was labeled following injections into the "arm area" of the APA was caudal and ventral to the dentate region that was labeled following injections into the "arm area" of the primary motor cortex. This observation provides evidence for two "arm areas" in the dentate: one anatomically related to the APA, and the other related to the primary motor cortex. More than one route of transport may be responsible for the labeling of cerebellar neurons. We propose that the labeling observed in the dentate nucleus reflects the pattern of connections in the cerebellothalamocortical pathways that link the dentate with the cerebral cortex. Thus, our observations support the concept proposed by Schell and Strick (J. Neurosci. 4:539-560, '84)--that the cortical targets of the dentate nucleus include both the primary motor cortex and the APA.

Animals↗
PubMed1994

Analysis of variations in mortality rates with small numbers.

OBJECTIVE: We present a Monte Carlo technique to evaluate if observed mortality rates differ from model-predicted rates for situations when the number of deaths is small. DATA SOURCES: We used Medicare hospital claims and model-predicted mortality rates from the Health Care Financing Administration (HCFA) for the 169 acute care hospitals in Georgia. The HCFA data provided model-predicted mortality rates at 30 days postadmission for 17 conditions and procedures of interest. The model-predicted rates calculated by HCFA were adjusted for patient factors, including demographic characteristics, principal diagnosis, and comorbidities. STUDY DESIGN: We test the hypothesis that model-predicted 30-day mortality rates at the 169 hospitals differ significantly from the observed 30-day mortality rates. Our approach uses a test statistic that resembles a chi-square statistic, and Monte Carlo simulations to estimate the distribution of the test statistic under the null hypothesis of no differences between the observed and predicted rates. We illustrate the method using two conceptually similar simulation models. We use results of the simulations to estimate p-values and compare these results with p-values associated with the nominal chi-square distribution. DATA EXTRACTION METHODS: We extracted 30-day observed and predicted mortality rates for Medicare beneficiaries for federal fiscal year 1990 for 17 conditions and procedures of interest. PRINCIPAL FINDINGS: If the number of deaths in some hospitals is small, p-values calculated using the nominal chi-square distribution can be misleading, thus supporting the usefulness of our simulation method. CONCLUSIONS: The Monte Carlo simulation is an appropriate approach to the analysis of hospital mortality or small area analysis for situations in which the number of deaths is small.

Analysis of Variance↗
PubMedDate not supplied

Bionomical and cytogenetic heterogeneities of Anopheles funestus in Senegal.

Malaria transmission by Anopheles funestus was investigated from May 1994 to September 1997 in different locations from western to eastern Senegal along the northern border of The Gambia. 10515 A. funestus were captured on human volunteers or by indoor pyrethrum spraying. Circumsporozoite protein rates showed that A. funestus had a high infection rate, 2-7%, in the whole of the study area. Analysis of feeding behaviour showed great variation of anthropophilic rates from western Senegal, where populations were highly anthropophilic, to eastern Senegal, where they were much more zoophilic. In eastern Senegal many females captured in bedrooms had fed outside on horses. Polytene chromosome analysis showed that the general pattern of karyotype distribution is consistent with the hypothesis of 3 chromosomally differentiated populations of A. funestus. In samples from a central part of the study area, analysis showed lack of karyotype intergradation with a deficit of heterokaryotypes, suggesting the presence of 2 genetically differentiated populations in an area of sympatric.

Animals↗
PubMed2002

Ultrasound pretreatment of elemental iron: kinetic studies of dehalogenation reaction enhancement and surface effects.

This work presents data showing the kinetic improvement afforded by ultrasound pretreatment and illustrates the physical and chemical changes that take place at the iron surface. First-order rate constants improved as much as 78% with 2h of ultrasound pretreatment. Scanning electron microscopy (SEM) and surface area analysis were used for confirmation of the physical changes that take place after ultrasound was used on iron surfaces exposed to a variety of conditions. X-ray photoelectron spectroscopy was used to determine chemical surface characteristics before and after ultrasound use. SEM and surface area analysis showed that ultrasound use clears the iron surface of debris increasing the surface area up to 169%. In addition, exposure to ultrasound alters ratios of surface species, such as adventitious carbon to carbonyl carbon and iron to oxygen, and removed hydroxides thus making the iron more reactive to reductive dehalogenation.

Halogens↗
PubMed1977

Apatite crystals in pseudoxanthoma elasticum: a combined study using electron microscopy and selected area diffraction analysis.

Calcium deposits in elastic fibers of involved skin of patients suffering from pseudoxanthoma elasticum have previously been reported. In the present work, the crystalline structure and composition were studied. Involved skin was obtained from 5 patients. Bright-field and dark-field electron microscopy and selected area electron diffraction of the calcium deposits were applied. The study demonstrates calcium apatite crystals.

Apatites↗
PubMed2001

Cause-specific stillbirth and neonatal death in Sweden: a catchment area-based analysis.

UNLABELLED: A register-based study of the impact of obstetric and neonatal care on stillbirth and neonatal death rate was performed on all births in Sweden in 1983-1995. Each birth was assigned to a primary delivery hospital where the mother with a term singleton pregnancy was most likely to have been delivered (not possible for 25% of the deliveries), and the catchment areas of each hospital were classified according to the level of care of that hospital. Only small differences in total mortality existed between the different levels of care of the primary hospital: areas served by primary hospitals with obstetric service and resources for neonatal intensive care including continuous positive airway pressure but without facilities for ventilator treatment for prolonged periods showed a 7% excess risk of stillbirth or neonatal death. CONCLUSION: In areas with the lowest level of care of the primary delivery hospitals (with no or only basic neonatal care) the total mortality was not increased, indicating that the referral system works well. When the analysis was repeated for specific causes of death, more marked differences were noted, especially for death due to obstetric complications where the death risk increased with decreasing level of care of the primary delivery hospital. Even though no marked differences in total mortality were seen, a further reduction can be obtained by increasing referral for some specific conditions.

Cause of Death↗
PubMed1994

[Analysis of electrically evoked response in relation to the central pathway of the cat (3). Current source density analysis in area 17 of cats].

We analyzed current source density and multiple unit activity of area 17 of cats in response to transcorneal electrical stimuli to clarify the localization of the transmembrane current flows contributing to the generation of the electrically evoked response. The results of the current source density analysis were as follows. 1. Current sinks within 20 ms were observed in layers 4 and 6. 2. Current sinks corresponding to N3 (latency 35 ms) were detected in layers 4 and lower 3 and current sources were in the supragranular layers. 3. Current sinks with a latency of more than 40 ms were observed in the supragranular layers. Simultaneous multiple unit activity was present in cases 1 and 2. With increased stimulus frequency or double electrical stimuli, the current sinks corresponding to N3 were decreased. These findings indicate that N1 (latency 9 ms) and N2 (latency 20 ms) reflect near-field potentials generated by geniculocortical afferents in layers 4 and 6, and that N3 is a post-and polysynaptic component. In addition, it appears that dipoles consisting of cell bodies and apical dendrites of pyramidal cells in layer 3 generated by satellite cell in layer 4, play a major role in generating N3.

Animals↗
PubMed2005

The validity of reported tensile bond strength utilizing non-standardized specimen surface areas. An analysis of in vitro studies.

PURPOSE: To assess and discuss the true value and perceived relevance of present day dental adhesive tensile bond strength studies. There are flaws and inconsistencies present in the data due to the inherent variations in testing methods, conditions, and types of samples prepared. In particular, surface areas of specimens need to be standardized. This review considers the significant impact of different surface areas of tooth specimens utilized in testing. RESULTS: On review of the data, relatively higher MPa values do not necessarily indicate improved dental adhesive products or procedures.

Dental Bonding↗
PubMedDate not supplied

Preventable hospitalizations in primary care shortage areas. An analysis of vulnerable Medicare beneficiaries.

BACKGROUND: Health care outcomes among vulnerable elderly populations (defined in this study as Medicare beneficiaries who rated their overall general health as "fair" or "poor") are a growing concern. Recent studies suggest that potentially preventable hospitalizations may be useful for identifying poor ambulatory health care outcomes among vulnerable populations. OBJECTIVES: To determine if Medicare beneficiaries in fair or poor health are at increased risk of experiencing a preventable hospitalization if they reside in primary care health professional shortage areas. DESIGN: A survey of Medicare beneficiaries from the 1991 Medicare Current Beneficiary Survey. PATIENTS: Medicare beneficiaries living in the community. RESULTS: Medicare beneficiaries in fair or poor health were 1.82 times more likely to experience a preventable hospitalization if they resided in a primary care shortage area (95% confidence interval, 1.18-2.81). After controlling for educational level, income, and supplemental insurance, Medicare beneficiaries in fair or poor health were 1.70 times more likely to experience a preventable hospitalization if they resided in a primary care shortage area (95% confidence interval, 1.09-2.65). CONCLUSIONS: Medicare beneficiaries in fair or poor health are more likely to experience a potentially preventable hospitalization if they live in a county designated as a primary care shortage area. Provision of Medicare coverage alone may not be enough to prevent poor ambulatory health care outcomes such as preventable hospitalizations. Improving health care outcomes for vulnerable elderly patients may require structural changes to the primary care ambulatory delivery system in the United States, especially in designated shortage areas.

Aged↗
PubMed2006

Quantum computing based on vibrational eigenstates: pulse area theorem analysis.

In a recent paper [D. Babikov, J. Chem. Phys. 121, 7577 (2004)], quantum optimal control theory was applied to analyze the accuracy of quantum gates in a quantum computer based on molecular vibrational eigenstates. The effects of the anharmonicity parameter of the molecule, the target time of the pulse, and the penalty function on the accuracy of the qubit transformations were investigated. We demonstrate that the effects of all the molecular and laser-pulse parameters can be explained utilizing the analytical pulse area theorem, which originates from the standard two-level model. Moreover, by analyzing the difference between the optimal control theory results and those obtained using the pulse area theorem, it is shown that extremely high quantum gate fidelity can be achieved for a qubit system based on vibrational eigenstates.

Comment↗
PubMed1992

Primary causes of medical instability of Medicare patients at discharge 1990-1991.

BACKGROUND: HCFA-sponsored Peer Review Organizations nationwide have been criticized by organized medicine, Medicare beneficiaries and interested Congressional parties for being punitive without exploiting educational opportunities garnered through their massive data collection capabilities. Until now this data has been poorly analyzed and has not been adequately utilized as a positive motivational tool. METHODS: HCFA has developed, with the cooperation of the medical community, six generic screens for Peer Review Organizations to utilize when evaluating quality care provided Medicare beneficiaries in an acute care setting. Through the sheer volume of cases seen, significant inpatient information can be obtained that cannot be duplicated in any other epidemiological endeavor. Line item discrepancies can be further studied through small-area-analysis to determine "who" as well as "what" may be the problem. RESULTS: By compiling and reviewing data in a systematic manner over two years (1990-1991), the Alabama Quality Assurance Foundation (AQAF) has singled out problems with patient medical stability at discharge as the predominant concern for care providers and reviewers alike. CONCLUSIONS: Having determined the primary problem in rendering quality care in a Prospective Payment System to Medicare beneficiaries lies in premature discharges, subsequent small-area-analysis further narrows the focus of concerned individuals. Hopefully, practitioners and providers alike will act on their own initiative in correcting this problem. Follow-up review will be utilized to assure this self-corrective action.

Alabama↗
PubMed2000

Benefits of glatiramer acetate on disability in relapsing-remitting multiple sclerosis. An analysis by area under disability/time curves. The Copolymer 1 Multiple Sclerosis Study Group.

New immunomodulatory therapies for relapsing-remitting multiple sclerosis (RRMS) have well-documented effects in reducing relapses, but it has been difficult to demonstrate their benefits on disability in relatively short treatment trials. Commonly utilised disability outcome measures are problematic both in usefulness and clinical interpretation when applied to MS subjects with fluctuating and variable disease courses. An alternative technique is to use the summary measure 'area under the disability/time curve' (AUC) to index the total in-trial morbidity experienced by patients. In this study, we applied AUC analyses to the serial Expanded Disability Status Scale (EDSS) scores from the U.S. multicentre, Phase III, two-year core study of glatiramer acetate in 251 RRMS patients. When all available EDSS evaluations were analysed with AUC(CHANGE) ('combined data', including relapse-related assessments), active treatment was significantly superior to placebo (P=0.018). The benefits of glatiramer acetate persisted when transient relapse effects were reduced by using 'scheduled visit data' only (P=0.021). With the more conservative AUC(SUM) measure, significant active treatment effects remained (P=0.029 and 0.046, for both 'combined' and 'scheduled visit' data, respectively). Subgroup calculations performed with baseline disability stratified at EDSS 3.5 also showed benefits of treatment over placebo, but statistical significance was not reached. This analysis of data from a Phase III treatment trial illustrates the AUC summary measure technique and provides further evidence of the efficacy of glatiramer acetate in RRMS.

Disability Evaluation↗