Population density effect on radio frequencies interference (RFI) in radio astronomy

2012 ◽  
Author(s):  
Roslan Umar ◽  
Zamri Zainal Abidin ◽  
Zainol Abidin Ibrahim ◽  
Mohd Saiful Rizal Hassan ◽  
Zulfazli Rosli ◽  
...  
Keyword(s):  
Population Density ◽  
Radio Astronomy ◽  
Density Effect ◽  
Radio Frequencies

Studies of gametophytes of Matteuccia struthiopteris (ostrich fern) in nature and in culture

1983 ◽  
Vol 61 (12) ◽  
pp. 3267-3270 ◽  
Author(s):  
P. von Aderkas
Keyword(s):  
Population Density ◽  
Field Data ◽  
Sex Expression ◽  
Density Effect

The sex expression of gametophytes of Matteuccia struthiopteris (L.) Todaro was compared in nature and in culture. Plants raised from multispore cultures (100 spores/cm2) exhibited the most variety in sexual–morphological types. Individually raised plants were slower to develop and showed less variety of sexual types than was found in the multispore cultures. There appeared to be a density effect on development. Field-collected gametophytes showed the least diversity, the populations being largely composed of poorly developed male and neuter plants. The experimental and field data are considered in relation to antheridiogen and population density studies.

scholarly journals The Legal Defense of Radio Astronomy

1991 ◽  
Vol 112 ◽  
pp. 310-317
Author(s):  
James G. Ennis
Keyword(s):  
Remote Sensing ◽  
Radio Astronomy ◽  
Primary Objective ◽  
Space Research ◽  
Radio Interference ◽  
National Academy Of Sciences ◽  
Wildlife Tracking ◽  
Radio Frequencies ◽  
Legal Defense ◽  
Academy Of Sciences

The purpose of this paper is to describe one program of the National Academy of Sciences’ Committee on Radio Frequencies (“CORF”). This program uses legal means to protect radio astronomy frequencies from radio interference.CORF is composed of eminent scientists from the fields of radio astronomy, space research, remote sensing, meteorology, and wildlife tracking who use radio frequencies in conducting their research. CORF’s primary objective is to limit the level of harmful man-made interference in the bands used by these scientists as much as possible.

scholarly journals MASER (Measuring Analyzing & Simulating Emissions in Radio frequencies), a Toolbox for Low Frequency Radio Astronomy

2018 ◽  
Author(s):  
Baptiste Cecconi ◽  
Alan Loh ◽  
Pierre Le Sidaner ◽  
Renaud Savalle ◽  
Xavier Bonnin ◽  
...  
Keyword(s):  
Radio Astronomy ◽  
Low Frequency ◽  
Radio Frequencies

A critique of the «increasing population density effect»

1989 ◽  
Vol 4 (6) ◽  
pp. 515-523 ◽  
Author(s):  
K. R. Gibson ◽  
J. M. Calcagno
Keyword(s):  
Population Density ◽  
Density Effect

Density effect and optimum density of the urban population in China

Urban Studies ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 1760-1777 ◽  
Author(s):  
Hongjian Su ◽  
Houkai Wei ◽  
Jian Zhao
Keyword(s):  
Population Density ◽  
Urban Population ◽  
Urban Land Use ◽  
Density Effect ◽  
The Public ◽  
Optimum Density ◽  
Employment Density ◽  
Dependent Variables ◽  
Passenger Volume ◽  
The City

This article examines the density effect and the optimum density of the urban population using panel data from China’s 284 cities from 2006 to 2010. Considering the endogeneity problem from the employment density in the density effect, we employ the density of the public transport passenger volume instead, and we control the size effect and the structure effect to obtain more reasonable results. Our results indicate that, using the dependent variables of product per labour and wage, the density effect shows an inverted U shape. Further study shows that the optimum urban population density gauged by the total urban population divided by the built-up area is approximately 13,000 people per km2 for the prefecture-level cities in China. The results are robust. Based on the concept and value of the optimum urban population density, China has a huge potential urban land use capacity of approximately 28% of total built-up area. China’s expansion of the city built-up area and the process of population urbanisation should be coordinated by the optimum urban population density.

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