105,709 research outputs found
Two-micron spectrophotometry of the galaxy NGC 253
A very strong Brackett-gamma hydrogen emission line, and the 2.3 micron CO stellar absorption feature were measured in NGC 253. The presence and strength of the CO feature indicates that late type giant stars produce most of the 2.2 micron continuum emission, while the rate of ionization implied by strength of the Brackett-gamma line indicates that much, perhaps all, of the luminosity detected at far infrared wavelengths originates from a large number of OB stars. As compared to the corresponding region of the Galaxy, the number of massive young stars in the central 200 pc of NGC 253 is thirty times greater, but the total mass of stars is roughly the same
Vortex Fluctuations in the Critical Casimir Effect of Superfluid and Superconducting Films
Vortex-loop renormalization techniques are used to calculate the magnitude of
the critical Casimir forces in superfluid films. The force is found to become
appreciable when size of the thermal vortex loops is comparable to the film
thickness, and the results for T < Tc are found to match very well with
perturbative renormalization theories that have only been carried out for T >
Tc. When applied to a high-Tc superconducting film connected to a bulk sample,
the Casimir force causes a voltage difference to appear between the film and
bulk, and estimates show that this may be readily measurable.Comment: 4 pages, 5 figures, Revtex 4, typo correctio
Ground-based 1- to 32-microns observations of ARP 220: Evidence for a dust-embedded AGN?
New observations of the 10 and 20 micron size of the emission region in Arp 220 are presented. Also given are ground based photometry from 1 to 32 micron including measurements of the strength of the silicate feature at 10 micron. The results show that the 20 micron size of Arp is smaller than 1.5 arcsec (500 pc); comparison of IRAS and ground based observations show that IRAS 12 micron flux measured with a large arcmin beam is the same as that seen from the ground with a 3 arcsec aperture. At 10 micron a deep silicate absorption feature is seen that corresponds to a visual extinction of about 50 mag. These results suggest that a very significant portion of the 10 to the 12th power L sub 0 infrared luminosity from Arp 220 comes from a region less than or of the order of 500 pc in diameter. When these results are combined with recent measurement of a broad Brackett alpha line by DePoy and an unresolved 2.2 micron source by Neugebauer, Matthews and Scoville, a very attractive possibility for the primary luminosity source Arp 220 is a dust embedded compact Seyfert type nucleus
Energy and environmental burdens of organic and non-organic agriculture and horticulture
Production of 10 major commodities in England and Wales was studied using Life Cycle Analysis (LCA). Organic and non-organic (contemporary conventional) systems were compared. Organic production was generally less energy consuming, except for poultry meat, eggs and tomatoes. Environmental burdens, such as global warming potential or eutrophication were often greater per unit of production from organic than non-organic systems
Liquid cooled brassiere and method of diagnosing malignant tumors therewith
A device for enhancing the detection of malignant tissue in the breasts of a woman was described. A brassiere-like garment which is fitted with a pair of liquid-perfused cooling panels which completely and compliantly cover the breasts and upper torso was studied. The garment is connected by plastic tubing to a liquid cooling system comprising a fluid pump, a solenoid control valve for controlling the flow of fluid to either the cooling unit or the heating unit, a fluid reservoir, a temperature sensor in the reservoir, and a restrictor valve to control the pressure in the garment inlet cooling line
The time evaluation of resistance probability of a closed community against to occupation in a Sznajd like model with synchronous updating: A numerical study
In the present paper, we have briefly reviewed Sznajd's sociophysics model
and its variants, and also we have proposed a simple Sznajd like sociophysics
model based on Ising spin system in order to explain the time evaluation of
resistance probability of a closed community against to occupation. Using a
numerical method, we have shown that time evaluation of resistance probability
of community has a non-exponential character which decays as stretched
exponential independent the number of soldiers in one dimensional model.
Furthermore, it has been astonishingly found that our simple sociophysics model
is belong to the same universality class with random walk process on the
trapping space.Comment: 12 pages, 5 figures. Added a paragraph and 1 figure. To be published
in International Journal of Modern Physics
The eleven observations of comets between 687 AD and 1114 AD recorded in the Anglo Saxon Chronicle
This research paper is an examination of the eleven cometary references (679AD, 729AD, 892AD, 950AD, 975AD, 995AD, 1066AD, 1097AD, 1106AD, 1110AD and 1114AD) found in the various manuscripts of The Anglo Saxon Chronicle between 678 AD and 1114 AD. The manuscripts contain more than 35 celestial observations. This is an examination of astronomical phenomena and other climatic or natural events, that are described in The Anglo Saxon Chronicle, which is also referred to as The Old English Annals
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