9,446 research outputs found
Relative annoyance and loudness judgements of various simulated sonic boom waveforms
Effects of various simulated sonic boom waveforms on human subjective respons
The APM Galaxy Survey III: An Analysis of Systematic Errors in the Angular Correlation Function and Cosmological Implications
We present measurements of the angular two-point galaxy correlation function,
, from the APM Galaxy Survey. The performance of various estimators
of is assessed using simulated galaxy catalogues and analytic arguments.
Several error analyses show that residual plate-to-plate errors do not bias our
estimates of by more than . Direct comparison between our
photometry and external CCD photometry of over 13,000 galaxies from the Las
Campanas Deep Redshift Survey shows that the rms error in the APM plate zero
points lies in the range 0.04-0.05 magnitudes, in agreement with our previous
estimates. We estimate the effects on of atmospheric extinction and
obscuration by dust in our Galaxy and conclude that these are negligible. We
use our best estimates of the systematic errors in the survey to calculate
corrected estimates of . Deep redshift surveys are used to determine the
selection function of the APM Galaxy Survey, and this is applied in Limber's
equation to compute how scales as a function of limiting magnitude. Our
estimates of are in excellent agreement with the scaling relation,
providing further evidence that systematic errors in the APM survey are small.
We explicitly remove large-scale structure by applying filters to the APM
galaxy maps and conclude that there is still strong evidence for more
clustering at large scales than predicted by the standard scale-invariant cold
dark matter (CDM) model. We compare the APM and the three dimensional power
spectrum derived by inverting , with the predictions of scale-invariant CDM
models. We show that the observations require in the range
0.2-0.3 and are incompatible with the value of the standard CDM
model.Comment: 102 pages, plain TeX plus 41 postscript figures. Submitted to MNRA
The Apm Galaxy Survey IV: Redshifts of Rich Clusters of Galaxies
We present redshifts for a sample of 229 clusters selected from the APM
Galaxy Survey, 189 of which are new redshift determinations. Non-cluster galaxy
redshifts have been rejected from this sample using a likelihood ratio test
based on the projected and apparent magnitude distributions of the cluster
fields. We test this technique using cluster fields in which redshifts have
been measured for more than 10 galaxies. Our redshift sample is nearly complete
and has been used in previous papers to study the three dimensional
distribution of rich clusters of galaxies. 157 of the clusters in our sample
are listed in the Abell catalogue or supplement, and the remainder are new
cluster identifications.Comment: 15 pages UUencoded compressed postscript. Submitted to Monthly
Notices of the R.A.
Genomic regions associated with common root rot resistance in the barley variety Delta
Common root rot (CRR) caused by Bipolaris sorokiniana is a serious disease constraint in the dry temperate cereal growing regions of the world. Currently little is known about the genetic control of resistance to CRR in cereals. In this study based on a Delta/Lindwall barley population we have undertaken a bulked segregant analysis (BSA) and whole genome mapping approach utilising Diversity Arrays Technology (DArT) to identified quantitative trait loci (QTL) associated with CRR expression. One QTL each was identified on chromosomes 4HL and 5HL explaining 12 and 11% of the phenotypic variance, respectively
Conservation laws in the continuum systems
We study the conservation laws of both the classical and the quantum
mechanical continuum type systems. For the classical case, we introduce
new integrals of motion along the recent ideas of Shastry and Sutherland (SS),
supplementing the usual integrals of motion constructed much earlier by Moser.
We show by explicit construction that one set of integrals can be related
algebraically to the other. The difference of these two sets of integrals then
gives rise to yet another complete set of integrals of motion. For the quantum
case, we first need to resum the integrals proposed by Calogero, Marchioro and
Ragnisco. We give a diagrammatic construction scheme for these new integrals,
which are the quantum analogues of the classical traces. Again we show that
there is a relationship between these new integrals and the quantum integrals
of SS by explicit construction.Comment: 19 RevTeX 3.0 pages with 2 PS-figures include
Why is timing of bird migration advancing when individuals are not?
Recent advances in spring arrival dates have been reported in many migratory species but the mechanism driving these advances is unknown. As population declines are most widely reported in species that are not advancing migration, there is an urgent need to identify the mechanisms facilitating and constraining these advances. Individual plasticity in timing of migration in response to changing climatic conditions is commonly proposed to drive these advances but plasticity in individual migratory timings is rarely observed. For a shorebird population that has significantly advanced migration in recent decades, we show that individual arrival dates are highly consistent between years, but that the arrival dates of new recruits to the population are significantly earlier now than in previous years. Several mechanisms could drive advances in recruit arrival, none of which require individual plasticity or rapid evolution of migration timings. In particular, advances in nest-laying dates could result in advanced recruit arrival, if benefits of early hatching facilitate early subsequent spring migration. This mechanism could also explain why arrival dates of short-distance migrants, which generally return to breeding sites earlier and have greater scope for advance laying, are advancing more rapidly than long-distance migrants
RBSC-NVSS Sample. I. Radio and Optical Identifications of a Complete Sample of 1500 Bright X-ray Sources
We cross-identified the ROSAT Bright Source Catalog (RBSC) and the NRAO VLA
Sky Survey (NVSS) to construct the RBSC-NVSS sample of the brightest X-ray
sources (>= 0.1 counts/s or ~1E-12 ergs/cm/cm/s in the 0.1-2.4 keV band) that
are also radio sources (S >= 2.5 mJy at 1.4 GHz) in the 7.8 sr of extragalactic
sky with |b| > 15 degrees. and delta > -40 degrees. The sky density of NVSS
sources is low enough that they can be reliably identified with RBSC sources
having average rms positional uncertainties = 10 arcsec. We used the more
accurate radio positions to make reliable X-ray/radio/optical identifications
down to the POSS plate limits. We obtained optical spectra for many of the
bright identifications lacking published redshifts. The resulting X-ray/radio
sample is unique in its size (N ~ 1500 objects), composition (a mixture of
nearly normal galaxies, Seyfert galaxies, quasars, and clusters), and low
average redshift ( ~ 0.1).Comment: 35 LaTeX pages including 6 eps figures + 40 LaTeX page table2
(landscape) w/ AASTeX 5.0; accepted to ApJ
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