Measure Of Population Density Research Articles

Electron temperature determination in LTE and non-LTE plasmas

A method is presented for calculating electron temperatures ( T e ) in dense plasmas, which does not assume equivalence with the excited level distribution temperatures ( T ex). The method involves the upper-level Saha ionization equation at the ionization limit, the limiting weighted population density ( N I / g I ) obtained from measured population densities and the experimentally obtained electron density. Electron temperatures calculated for 0.1-bar hydrogen and 1-atm helium and argon arcs are found to be up to twice as large as excited level distribution temperatures. For subatmospheric argon arcs, the calculated T e are equivalent to the excitation temperature of the middle levels, but are two to three times smaller than the quoted T ex for the highest levels. Reasons are discussed for the apparent invisibility of true electron temperatures and for differences between them and the excitation temperatures.

Open lung biopsy in children with diffuse lung disease.

<h3>Background</h3> A strict high legal age limit for alcohol purchases decreases adolescents’ access to alcohol, but little is known about long-term health effects. The aim was to estimate the effect of increased alcohol availability during adolescence on alcohol-related morbidity and mortality. <h3>Methods</h3> A nationwide register-based study using data from a natural experiment setting. In two regions of Sweden, strong beer (4.5%–5.6% alcohol by volume) became temporarily available for purchase in grocery stores for individuals 16 years or older (instead of 21) in 1967/1968. The intervention group was defined as all individuals living in the intervention area when they were 14–20 years old (n=72 110). The remaining Swedish counties excluding bordering counties, without the policy change, were used as the control group (n=456 224). The outcomes of alcohol-related morbidity and mortality were collected from the Hospital Discharge Register and Cause of Death Register, in which average follow-up times were 38 years and 41 years, respectively. HRs with 95% CIs were obtained by Cox regression analysis. <h3>Results</h3> In the fully adjusted model, no clear evidence of an association between increased alcohol availability during adolescence and alcohol-related morbidity (HR: 0.99, 95% CI 0.96 to 1.02) or mortality (HR: 1.02, 95% CI 0.95 to 1.10) was found. <h3>Conclusion</h3> The initial elevated risk of alcohol-related morbidity and mortality later in life among adolescents exposed to increased access to strong beer in Sweden vanished when a regional measure population density of locality was included in the model, which is important to consider in future research.

Cross-national comparison of population density.

The unresolved difficulties associated with defining and measuring population density strictly circumscribe the scope and nature of the conclusions that can be properly derived from differentials in man:land ratios. Any conclusions about human density will have meaning only to the extent that they are based on a recognition that this density must be viewed in both static and dynamic terms and that it cannot be isolated in analysis, from either the social and cultural setting, the demographic characteristics of the population, or the broader processes of social change within the society. In and of itself, the familiar man:land ratio says more about area than it does about either the human experience of density or the relation of population to resources. This ratio is therefore essentially meaningless as an indicator of comparative conditions of life among different countries and different geographic regions. The mere fact of having a relatively low average population density thus, does not automatically entitle a nation to complacency about its ability to adjust readily to future population change, either in terms of growth in numbers or in the geographic location of its people.

Serum and red cell folates, and serum vitamin B 12 in protein calorie malnutrition.

<h3>Background</h3> A strict high legal age limit for alcohol purchases decreases adolescents’ access to alcohol, but little is known about long-term health effects. The aim was to estimate the effect of increased alcohol availability during adolescence on alcohol-related morbidity and mortality. <h3>Methods</h3> A nationwide register-based study using data from a natural experiment setting. In two regions of Sweden, strong beer (4.5%–5.6% alcohol by volume) became temporarily available for purchase in grocery stores for individuals 16 years or older (instead of 21) in 1967/1968. The intervention group was defined as all individuals living in the intervention area when they were 14–20 years old (n=72 110). The remaining Swedish counties excluding bordering counties, without the policy change, were used as the control group (n=456 224). The outcomes of alcohol-related morbidity and mortality were collected from the Hospital Discharge Register and Cause of Death Register, in which average follow-up times were 38 years and 41 years, respectively. HRs with 95% CIs were obtained by Cox regression analysis. <h3>Results</h3> In the fully adjusted model, no clear evidence of an association between increased alcohol availability during adolescence and alcohol-related morbidity (HR: 0.99, 95% CI 0.96 to 1.02) or mortality (HR: 1.02, 95% CI 0.95 to 1.10) was found. <h3>Conclusion</h3> The initial elevated risk of alcohol-related morbidity and mortality later in life among adolescents exposed to increased access to strong beer in Sweden vanished when a regional measure population density of locality was included in the model, which is important to consider in future research.

A Tool for Measuring Population Density

The American Journal of Economics and SociologyVolume 31, Issue 4 p. 352-352 A Tool for Measuring Population Density First published: October 1972 https://doi.org/10.1111/j.1536-7150.1972.tb01141.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume31, Issue4October 1972Pages 352-352 RelatedInformation

Spectroscopic measurement of electron temperature in helium arc plasma

The intensities of the neutral helium spectral, lines emitted from helium plasma produced by the energetic arc have been measured, and the population densities of the energy levels of neutral heliumhave been calculated from them. Electron temperature could be deduced from them, since the distribution of the measured population densities above the. fifth principal quantum number was Maxwellian. Discharge conditions of helium arc were as folows; helium pressure at 10-2 torr, currents of 150, and 240 amp., and magnetic field. strength of 3540 gauss. In these cases the electron temperaturess of 0.19, 0.34, and 0, 34 ev respectively were obtained. It was considered from the radial intensity distribution of neutral helium lines that the measured electron temperatures were the values around the arc column.

Rekombination und Ionisation in einer stationären Hochfrequenzentladung

A cool hydrogen plasma in a steady state rf-discharge in a static magnetic field is investigated spectroscopically. The recombination rate of this plasma is determined. The essential three-body recombinations are taken into account for levels of medium quantum number, where the inverse process—ionizations from excited levels—is considerably lowered. Measured population densities are used for the determination of the recombination rate. The considerations include the effects of energetic electrons the presence of which—in addition to the bulk of cool electrons—has been detected by probe measurements. Within the limits of error the ionization rate calculated for the energetic electrons agrees with the recombination rate of the cool electrons.

A Simple Apparatus for Measuring Density of Insect Population1

Measuring population density is often difficult in field studies of insects. Direct counts of individuals per unit area are possible only with slow-moving species. The sweep net, in wide use for sampling the more active forms, gives only an estimate of relative numbers. A conversion factor, derived from some direct method of sampling, must be used for expressing sweep data in terms of absolute numbers (Beall 1935; Gray and Treloar 1933; and Romney 1945). For sampling the entire aboveground insect fauna the suction-type apparatus of Dietrick et al. (1959) possesses the most general applicability for different vegetational types and species. The suction apparatus, however, is expensive and an extensive laboratory setup is needed for separation of the material collected, if an investigator is interested only in one or a few species of the insect fauna, it is sometimes possible to utilize a faster and less expensive sampling procedure designed specifically for a restricted group of species, such as that described in this note.