Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Population Statistics”

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 181 records · Page 10Linked to original sources
PubMed2002

Field statistics of two vectorially superposed wave populations.

Field statistics of observed waves and radiation constrain the physics of the emission process and source region. However, data often contain two or more superposed signals or a signal superposed on a noise background, creating difficulties for interpretation. Here, the combined probability distribution of the field formed by vector superposition of two signals, each with specified statistics, is written as a double integral with integrable singularities. The analytic result and its numerical solutions for combinations of Gaussian and lognormally distributed signals show that these predictions differ from those for field or intensity convolution and from the individual wave distributions. At high fields, the combined distribution takes the qualitative form of the dominant individual distribution (which is localized or otherwise extends to larger fields) but develops a significant tail at low fields due to vector superposition of almost antiparallel fields with similar magnitudes. It is shown that very nearly power-law distributions can develop in significant field domains, despite neither component distribution being power law. This is relevant to alternative interpretations in terms of self-organized criticality and certain modulational wave instabilities. The formalism is then applied to observations of the Vela pulsar, resulting in greatly improved fits to data and different interpretations. Specifically, the results are strong evidence that stochastic growth theory (SGT) is relevant and that the approximate power-law statistics found at some phases are not intrinsic but rather due to vector convolution of a Gaussian background with a lognormal; the latter is interpretable in terms of SGT. The field statistics are consistent with the emission mechanism being a direct linear instability or indirect generation via linear mode conversion of nonescaping waves driven by a linear instability. They are inconsistent with nonlinear self-focusing instabilities generating the observed pulsar radiation. This formalism and its results should also be widely applicable to other types of wave growth in inhomogeneous media.

Journal Article↗
PubMedDate not supplied

Metatarsus primus elevatus in hallux rigidus: fact or fiction?

Two hundred seventy-five lateral weightbearing radiographs of isolated pathology were reviewed and stratified into hallux rigidus (n = 100), hallux valgus (n = 75), plantar fasciitis (n = 50), and Morton's neuroma (n = 50) groups. The patient population consisted of healthy individuals with no history of foot trauma or surgery. The first to second metatarsal head elevation, Seiberg index, first to second sagittal intermetatarsal angle, first to fifth metatarsal head distance, and hallux equinus angle were measured in each population. Statistically significant differences were found between the hallux valgus, plantar fasciitis, and Morton's neuroma populations and the hallux rigidus population, which showed greater elevation of the first metatarsal relative to the second for each radiographic measurement technique. In the hallux rigidus population, there was a statistically significant difference between grade II and grades I and III regarding the first to fifth metatarsal head distance (greater in grade II) and the hallux equinus angle (lower in grade II). A review of the literature and comparison with historical controls reveals that metatarsus primus elevatus exists in hallux rigidus and is greater than that found in hallux valgus, plantar fasciitis, and Morton's neuroma groups.

Adult↗
PubMed1991

Heart rate, anxiety, anger, and arousal reactions to enforced time-wasting: dependence on reactive uncontrol, work involvement, and dominance factors of 'type A'.

The factor structure of 'Type A' was examined in an experiment derived from the observation of Frankenhaeuser et al. (1980) that 'Type A' people are abnormally 'aroused' when deprived of work. Questionnaire scales were used which dissected 'Type A' (based on replicated factor analyses). The sample statistics for 21 female volunteers approximated the parent population statistics on orthogonal scales of Work Involvement (WI), Reactive Uncontrol (RU) and Dominance (D). The laboratory session involved reading for 15 min: (a) self-chosen 'useful' work material and (b) material judged by subjects (Ss) to be 'useless'. Ss and trained observers used the same scales for rating anxiety, arousal and anger states during reading periods. Observers interpreted facial expressions from video-tapes. Finger pulse amplitude and tonic heart rate (HR) were recorded during reading periods. RU (but not WI or D) correlated negatively with HR level and positively with increases in both HR and observed arousal under time-wasting conditions. Combination of changes in HR and observed arousal in a multiple R gave optimum 'prediction' of RU. While much evidence supported Frankenhaeuser's (1980) hypothesis, the multifactorial nature of 'Type A' was demonstrated.

Adolescent↗
PubMed1987

Nigeria.

Explore the source record for details and available documents.

Africa↗
PubMed1994

[Moslems and Hindus in the Netherlands: revised time series].

Estimates of the numbers of Muslim, Hindu, and Buddhist residents of the Netherlands are presented and techniques for producing such estimates described. "Since 1971...estimated numbers of Moslems and Hindus/Buddhists have been...computed annually with the aid of data taken from the international migration statistics. Population growth due to births and deaths was calculated by assuming that the crude rates for Turks, Moroccans, [Tunisians], Pakistani and Indonesians living in the Netherlands apply to the Moslems, and those for the Surinamese apply to the Hindus/Buddhists. More recently other estimates have been achieved on the basis of enumerations from municipal population registers." (SUMMARY IN ENG)

Culture↗
PubMed2000

Epidemiology of ectopic pregnancy during a 28 year period and the role of pelvic inflammatory disease.

OBJECTIVES: We analysed the epidemiology of ectopic pregnancy (EP) during a 28 year period, 1970-97, using methods applicable to ecological studies in order to test the hypothesis that a reduction of pelvic inflammatory disease (PID) will be associated with a decrease of EP. METHODS: Hospital records of patients aged 15-54 admitted to our department of gynaecology were reviewed for EP and PID for the period 1 January 1970 to 31 December 1997. EP for the period 1970-4 was based on available statistics. The total number for EP was 1270 and for PID 2559. The total population for the catchment area was 100,000-120,000 during the study period. Incidences were age standardised and calculated using official population statistics to represent the average female population in the five 5 year periods 1970-4, 1975-9, 1980-4, 1985-9, 1990-4, and in each of the consecutive years 1995, 1996, and 1997. Incidences for EP were calculated per 1000 women and per 1000 pregnancies while those for PID per 1000 women. National statistical data of EP were available for 1975-94 and were used for comparison with the local study. RESULTS: The EP incidences increased from 7.7 per 1000 pregnancies in the first 5 year period to 13.4 in the second, and continued to rise for another decade reaching the peak figures of 16.6 in 1985-9--that is, more than a twofold increase. Since then and to 1997 the EP incidence has decreased by 30%. PID admissions increased during the study period from 2.7 per 1000 women in the first 5 year period to 3.2 in the second. From then on they continuously decreased and reached a low of 0.5 in 1997. The greatest changes occurred in women < or = 24 years of age. The peak incidence for this age group was 7.7 in 1975-9, and the lowest was 0.4 per 1000 women in 1996. The greatest reduction of EPs was noted for women < or = 24 years old, from a high of 10.0 in 1975-9, coinciding with the peak incidence of PID, to a low of 4.0 in 1997, a reduction of 58.4%. The incidence of EP was two to three times higher in women > or = 25 years old, most obvious in those > or = 30 years, with peak figures of 20.9 per 1000 pregnancies in 1985-9, and 13.9 in 1997, a reduction of 33.4% and the lowest figures for the past 23 years. For women aged 25-29 years the incidence peaked in the previous 5 year period 1980-4--that is, one 5 year period later than for those < or = 24 years, which we interpret as cohort effects in relation to PID. CONCLUSIONS: Reduction of PID was strongly associated with a decline of EP. The decline was greater and immediate for women < or = 24 years old, than for those > or = 25 years. The two to three times higher EP incidence in women > or = 25 years of age was most probably due to a cohort effect as the peak of PID occurred a decade earlier in women < or = 24 years old. Prevention of PID may not only reduce EP but also reduce adverse effects on tubal patency.

Adolescent↗
PubMed2007

Pleistocene isolation in the Northwestern Pacific marginal seas and limited dispersal in a marine fish, Chelon haematocheilus (Temminck & Schlegel, 1845).

The Northwestern Pacific has a unique tectonic and geographical history with several marginal seas separating Asia from the Pacific Ocean. During low sea level periods of Pleistocene glaciations, populations might have been isolated in three marginal seas: the Sea of Japan, East China Sea and South China Sea. Following postglacial sea level rise, we would expect the populations isolated in the three regions to have been homogenized by high dispersal potential. To assess these hypotheses, we explore the intraspecific phylogeographical patterns in redlip mullet, Chelon haematocheilus. Fragments of 435 bp at the 5' end of mitochondrial DNA control region were sequenced for 272 individuals from nine localities over most of the species' range. Three distinct lineages were detected, which might have diverged in the three marginal seas during Pleistocene low sea levels. Contrary to homogenization expectation, there were strong differences in the geographical distribution of the three lineages. Analyses of molecular variance and the population statistic Phi(ST) also revealed significant genetic structure among populations of the three marginal seas. These results indicate that gene flow in Chelon haematocheilus is far more restricted spatially than predicted by the potential dispersal capabilities of this species. The lack of phylogeographical structure in East China Sea may reflect a recent range expansion after the last glacial maximum and insufficient time to attain migration-drift equilibrium.

Animals↗
PubMed1991

Brazil is getting older: demographic changes and epidemiological challenges.

Population ageing is currently a phenomenon not only in developed countries but also in third world countries. In this paper the features of a population's ageing and the process of epidemiological transition are discussed along with the worldwide changes in age-structure. Population statistics in Brazil and the characteristics of the elderly population are presented and analysed in the light of recent changes. The Brazilian elderly population is also discussed, particularly the issues relating to the social cost of the aged population, its urban and rural distribution, the elderly by sex, marital status and level of schooling, and emphasis is given to the imbalance of the sexes and the consequences of it for women.

Age Factors↗
PubMed1992

Measuring stroke in the population: quality of routine statistics in comparison with a population-based stroke registry.

The validity of routine stroke data (official mortality statistics and hospital discharge registries) and a population-based MONICA stroke registry was assessed in a population of 309,806 25- to 74-year-old people in Sweden. The 'true' number of strokes in the population was estimated by screening for non-stroke diagnoses in death certificates and hospital discharge records and by a period of intensified search for otherwise unrecognized non-hospitalized stroke cases. Applying strict stroke criteria, the proportion of false-positive diagnoses was 10% and false-negative 17% in official mortality statistics. Among patients discharged alive from hospital, there were 32% false-positive and 6% false-negative stroke diagnoses. In the MONICA registry, the proportion of false-negative cases was 6% in fatal cases and 4% in non-fatal cases. Diagnostic information for subtyping stroke improved over time in non-fatal cases but remained essentially unchanged in fatal cases. We conclude that official mortality statistics give a reasonably good estimate of fatal stroke cases in Sweden, whereas hospital discharge records reflect poorly the incidence of stroke in the population. The overall quality of the population-based MONICA registry is good, although 4% of all strokes are missed. The proportion of unspecified stroke is substantial and changes over time; this makes longitudinal studies of stroke subtype difficult.

Adult↗
PubMed2002

Statistical power in stuttering research: a tutorial.

The capacity to make reliable inductive statements about populations is critical for the advancement of scientific knowledge. An important contribution to that advancement of knowledge is determining that effects are either present or not present in populations. Statistical power is an important methodological qualification for any research that presents statistical results, and particularly so for research that presents null results. In this paper we describe the statistical concept of power, outline parameters of research that influence it, and demonstrate how it is calculated. With reference to selected published research, attention is drawn to the problems associated with a body of underpowered research, one being that population effects may go undetected. One way to prevent this problem is to calculate power a priori in planning research and include confidence intervals when presenting the results of research. However, it is difficult, if not impossible in many cases, to obtain high participant numbers for communication disorders of low prevalence such as stuttering. With this in mind, the paper concludes with an attempt to open discussion about ways to redress the problems associated with statistical power.

Humans↗
PubMedDate not supplied

An indirect approach to the extensive calculation of relationship coefficients.

A method was described for calculating population statistics on relationship coefficients without using corresponding individual data. It relied on the structure of the inverse of the numerator relationship matrix between individuals under investigation and ancestors. Computation times were observed on simulated populations and were compared to those incurred with a conventional direct approach. The indirect approach turned out to be very efficient for multiplying the relationship matrix corresponding to planned matings (full design) by any vector. Efficiency was generally still good or very good for calculating statistics on these simulated populations. An extreme implementation of the method is the calculation of inbreeding coefficients themselves. Relative performances of the indirect method were good except when many full-sibs during many generations existed in the population.

Biometry↗
PubMed2005

Vision loss in Australia.

OBJECTIVE: To assess the prevalence and causes of vision loss in Australia and to project these data into the future. DESIGN: Synthesis of data from two cross-sectional population-based cohort studies--the Melbourne Visual Impairment Project and the Blue Mountains Eye Study--and extrapolation to the entire Australian population. SETTING AND PARTICIPANTS: 8376 community and 533 nursing home residents recruited between 1992 and 1996 in urban and rural Victoria and New South Wales. MAIN OUTCOME MEASURES: Age-standardised prevalence of low vision (visual acuity < 6/12) and blindness (visual acuity < 6/60) (both measured in the best eye, with spectacles if usually worn for distance vision), and their causes for the Australian population for 2000 to 2024, projected from Australian Bureau of Statistics population data. RESULTS: In 2004, 480,300 Australians were estimated to have low vision, including 50,600 with blindness. The most common causes of low vision were undercorrected refractive error (62%), cataract (14%) and age-related macular degeneration (10%). The latter was responsible for almost half of all cases of blindness. The numbers of people with low vision and blindness are projected to almost double by 2024. CONCLUSIONS: Vision loss in Australia is a much bigger problem than is usually recognised; 76% of low vision is caused by uncorrected refractive error or cataract, both readily treatable. However, the prevention and treatment of macular degeneration poses a major challenge.

Adult↗
PubMed1999

The Danish Prevention Register. A comprehensive health and socio-economic, individual based register.

The Danish Prevention Register has been created recently as a very comprehensive national individual based register, based on register linkage. The Prevention Register currently comprises eight registers, which have been linked together using the unique personal identification number. The register contains data from 1977 and onwards. From an international research perspective this register offers unique opportunities to the researchers. The eight registers can be divided into three groups: health-related registers, registers on living conditions and a Register of Population Statistics. The health-related registers are: Register of Causes of Death, National Patient Register (in-patients and out-patients) and Register of Health Insurance Statistics (primary health care, GPs). Within the next few years the register will be expanded with The Medical Birth Register. The Abortion Register and The Malformation Register. The registers on living conditions are: Longitudinal Register of Social and Employment Statistics, Employment Classification Module, Educational Classification Module and Register of Population and Housing Censuses. The Register allows for cross-sectional and follow-up studies and is used for administrative purposes as well as research purposes. An overview of the register is presented in the article. Earlier articles in the Danish Register series in DMB explain details of the registers.

Adolescent↗
PubMed1989

[392 cases of neoplasms of the salivary glands seen at the Odontostomatologic and Otorhinolaryngologic Clinic of Turin University. I].

Three-hundred-ninety-two cases of salivary gland cancer observed at Turin University Dental and Ear, Nose and Throat Clinics have been examined. Statistical analysis of the age and sex of patients shows the importance of selecting the statistical population and of its origin for the purpose of reliable statistical study, examining the whole set and its structural breakdown in the two Clinics.

Adolescent↗
PubMed1998

The Danish Fertility Database.

BACKGROUND: The Fertility Database (FTDB) in Statistics Denmark is solely based on data from other registers, which comprise data on a different number of birth cohorts and different time spans. The FTDB was established during 1989-1992 in order to provide a better tool for socio-demographic research on the developments in fertility. The variables included also make the register a valuable tool in medical research regarding reproductive outcome and characterization of parents. RESULTS: Based on the Register of Population Statistics, the FTDB comprises at present annual information on any woman and man in the fertile age in Denmark for the period 1980-1993, approximately 1.2 and 1.4 million persons, respectively. Their children are identified through various registers and for all children born 1973-1993 specific information on the birth was available from the Medical Register of Vital Statistics. The adult populations are described annually as regards education, occupation, income, social benefit and housing conditions. CONCLUSION: The FTDB has been used in a number of research projects; in some cases data from the FTDB have been linked with data from other registers. The FTDB is a valuable tool in demographic as well as medical research.

Adolescent↗