5,171 research outputs found
The origin of the infrared emission in radio galaxies. III. Analysis of 3CRR objects
We present Spitzer photometric data for a complete sample of 19 low redshift
(z<0.1) 3CRR radio galaxies as part of our efforts to understand the origin of
the prodigious mid- to far-infrared (MFIR) emission from radio-loud AGN. Our
results show a correlation between AGN power (indicated by [OIII] 5007 emission
line luminosity) and 24 micron luminosity. This result is consistent with the
24 micron thermal emission originating from warm dust heated directly by AGN
illumination. Applying the same correlation test for 70 micron luminosity
against [OIII] luminosity we find this relation to suffer from increased
scatter compared to that of 24 micron. In line with our results for the
higher-radio-frequency-selected 2Jy sample, we are able to show that much of
this increased scatter is due to heating by starbursts which boost the
far-infrared emission at 70 micron in a minority of objects (17-35%). Overall
this study supports previous work indicating AGN illumination as the dominant
heating mechanism for MFIR emitting dust in the majority of low to intermediate
redshift radio galaxies (0.03<z<0.7), with the advantage of strong statistical
evidence. However, we find evidence that the low redshift broad-line objects
(z<0.1) are distinct in terms of their positions on the MFIR vs. [OIII]
correlations.Comment: 31 pages, 3 figures, accepted for publication to Ap
Single agglutinates: A comparative study of compositions of agglutinitic glass, whole-grain, bulk soil, and FMR
Previous workers on single agglutinates have variously interpreted the composition of agglutinitic glass to represent impact melts of (1) bulk soil, (2) mixed components in finer sizes, and (3) microtargets. Separately, Papike has argued in favor of fusion of the finest fraction of bulk soils. Thirty-four single agglutinates were hand-picked from the mature Apollo 16 soil 61181 (I(sub s)/FeO = 82) and the FMR and chemical composition (INAA for Fe, Sc, Sm, Co, Ni, and Cr) of each agglutinate particle were measured. Thirteen of these single agglutinates were selected for electron beam microanalysis and imaging. Less than 1 micron spots were analyzed (for Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Fe, Ni, and Ba) on pure glassy areas (approximately ten in each particle) selected on the basis of optical and BSE images (avoiding all clasts and inclusions) with an electron microprobe to obtain average glass compositions of each single agglutinate
Evaluating Performance of Web Applications in (Cloud) Virtualized Environments
Web applications usually involve a number of different software libraries and tools (usually referred to as frameworks) each carrying out specific task/s and generating the corresponding overhead. In this paper, we show how to evaluate and even find out several configuration performance characteristics by using virtualized environments which are now used in data centers and cloud environments. We use specific and simple web software architectures as proof of concept, and explain several experiments that show performance issues not always expected from a conceptual point of view. We also explain that adding software libraries and tools also generate performance analysis complexities. We also shown that as an application is shown to scale, the problems to identify performance details and bottlenecks also scale, and the performance analysis also requires deeper levels of details.Instituto de Investigación en Informátic
'Chardonel' Grape
'Chardonel' resulted from the cross, 'SeyvaT x 'Chardonnay,'
made in 1953. Fruit were first observed in 1958, and the
original vine was propagated in 1960 under the number NY
45010. In later testing, it was re-named GW 9 (Geneva White 9)
for ease of identification in cooperatively run yield trials. The
vine was initially described as vigorous and productive with
large clusters
Flux Tube Solution in 5D Kaluza-Klein Theory
Spherically symmetric, vacuum solutions in 5D and 7D Kaluza-Klein theory are
obtained. These solutions are flux tubes with constant cross-sectional size,
located between (+) and (-) Kaluza-Klein's ``electrical'' and ``magnetic''
charges disposed respectively at and filled by constant
Kaluza-Klein ``electrical'' and ``magnetic'' fields. These objects are
surprisingly similar to the flux tubes which forms between two monopoles in
Type-II superconductors and also the hypothesized color field flux tube that is
thought to form between two quarks in the QCD vacuum.Comment: 8 pages, revtex, Title changed, references added and discussion of 7D
solution given. To be published in CQ
Full polarization study of SiO masers at 86 GHz
We study the polarization of the SiO maser emission in a representative
sample of evolved stars in order to derive an estimate of the strength of the
magnetic field, and thus determine the influence of this magnetic field on
evolved stars. We made simultaneous spectroscopic measurements of the 4 Stokes
parameters, from which we derived the circular and linear polarization levels.
The observations were made with the IF polarimeter installed at the IRAM 30m
telescope. A discussion of the existing SiO maser models is developed in the
light of our observations. Under the Zeeman splitting hypothesis, we derive an
estimate of the strength of the magnetic field. The averaged magnetic field
varies between 0 and 20 Gauss, with a mean value of 3.5 Gauss, and follows a
1/r law throughout the circumstellar envelope. As a consequence, the magnetic
field may play the role of a shaping, or perhaps collimating agent of the
circumstellar envelopes in evolved objects.Comment: 22 pages, accepted in A&A (19/12/2005
Research on the Geography of Agricultural Change: Redundant or Revitalized?
Future research directions for agricultural geography were the subject of debate in Area in the late 1980s. The subsequent application of political economy ideas undoubtedly revived interest in agricultural research. This paper argues that agricultural geography contains greater diversity than the dominant political economy discourse would suggest. It reviews ‘other’ areas of agricultural research on policy, post-productivism, people, culture and animals, presenting future suggestions for research. They should ensure that agricultural research continues revitalized rather than redundant into the next millennium
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing
The ocean’s role in regulating atmospheric carbon dioxide on glacial‐interglacial timescales remains an
unresolved issue in paleoclimatology. Reduced mixing between deep water masses may have aided oceanic
storage of atmospheric CO_2 during the Last Glacial Maximum (LGM), but data supporting this idea have
remained elusive. The δ^(13)C of benthic foraminifera indicate the Atlantic Ocean was more chemically
stratified during the LGM, but the nonconservative nature of δ^(13)C complicates interpretation of the LGM
signal. Here we use benthic foraminiferal δ^(18)O as a conservative tracer to constrain the ratio of meridional
transport to vertical diffusivity in the deep Atlantic. Our calculations suggest that the ratio was at least twice
as large at the LGM. We speculate that the primary cause was reduced mixing between northern and
southern component waters, associated with movement of this water mass boundary away from the zone of
intense mixing near the seafloor. The shallower water mass boundary yields an order of magnitude increase
in the volume of southern component water, suggesting its residence time may have increased substantially.
Our analysis supports the idea that an expanded volume of Antarctic Bottom Water and limited vertical
mixing enhanced the abyssal ocean’s ability to trap carbon during glacial times
Twenty Thousand-Year-Old Huts at a Hunter-Gatherer Settlement in Eastern Jordan
Ten thousand years before Neolithic farmers settled in permanent villages, hunter-gatherer groups of the Epipalaeolithic period (c. 22–11,600 cal BP) inhabited much of southwest Asia. The latest Epipalaeolithic phase (Natufian) is well-known for the appearance of stone-built houses, complex site organization, a sedentary lifestyle and social complexity—precursors for a Neolithic way of life. In contrast, pre-Natufian sites are much less well known and generally considered as campsites for small groups of seasonally-mobile hunter-gatherers. Work at the Early and Middle Epipalaeolithic aggregation site of Kharaneh IV in eastern Jordan highlights that some of these earlier sites were large aggregation base camps not unlike those of the Natufian and contributes to ongoing debates on their duration of occupation. Here we discuss the excavation of two 20,000-year-old hut structures at Kharaneh IV that pre-date the renowned stone houses of the Natufian. Exceptionally dense and extensive occupational deposits exhibit repeated habitation over prolonged periods, and contain structural remains associated with exotic and potentially symbolic caches of objects (shell, red ochre, and burnt horn cores) that indicate substantial settlement of the site pre-dating the Natufian and outside of the Natufian homeland as currently understood
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