13,983 research outputs found
Detection of abnormal recordings in Irish milk recorded data
peer-reviewedThe objective of this study was to detect abnormal recordings of milk yield, fat concentration and protein concentration in Irish milk-recorded data. The data consisted of 14,956 records from both commercial and experimental herds with 92% of the recordings recorded manually and the remainder recorded electronically. The method used in this paper was a modified version of the method employed by the Animal Improvement Programs Laboratory in Maryland, USA and conformed with the guidelines outlined by the International Committee of Animal Recording. The results illustrate the effectiveness of detecting abnormal recordings in Irish milk records. The method described in this paper, defines the upper and lower limits for each production trait and these limits along with the slope parameters were used to determine if a recording was abnormal or not. Three percent of milk yield recordings, 5% of fat concentration recordings and less than 1% of protein concentration recordings were found to be abnormal. The proportion of values declared abnormal in manually recorded and electronically recorded data were examined and found to be significantly different for fat concentration
Production of single-domain magnetite throughout life by sockeye salmon, Oncorhynchus nerka
Although single-domain particles of biogenic magnetite have been found in different species of pelagic fishes, nothing is known about when it is synthesized, or about whether the time during life when it is produced is correlated with the
development of responses to magnetic field stimuli. We have investigated production of biogenic magnetite suitable for use in magnetoreception in different life stages of the sockeye salmon, Oncorhynchus nerka (Walbaum). Sockeye
salmon were chosen because responses in orientation arenas to magnetic field stimuli have been demonstrated in both fry and smolt stages of this species.
We found significant quantities of single-domain magnetite in connective tissue from the ethmoid region of the skull of adult (4-year-old) sockeye salmon. The ontogenetic study revealed an orderly increase in the amount of magnetic material in the same region of the skull but not in other tissues of sockeye salmon fry, yearlings and smolts. The physical properties of this material closely matched
those of magnetite particles extracted from the ethmoid tissue of the adult fish. We suggest that single-domain magnetite particles suitable for use in magnetoreception
are produced throughout life in the ethmoid region of the skull in sockeye salmon. Based on theoretical calculations, we conclude that there are enough particles present in the skulls of the fry to mediate their responses to magnetic field direction. By the smolt stage, the amount of magnetite present in the front of the skull is sufficient to provide the fish with a magnetoreceptor capable of detecting small changes in the intensity of the geomagnetic field.
Other tissues of the salmon, such as the eye and skin, often contained ferromagnetic material, although the magnetizations of these tissues were usually more variable than in the ethmoid tissue. These deposits of unidentified magnetic material, some of which may be magnetite, appear almost exclusively in adults and so would not be useful in magnetoreception by young fish. We suggest that tissue from within the ethmoid region of the skull in pelagic fishes is the only site yet identified where magnetite suitable for use in magnetoreception is concentrated
Pre-school experience and Key Stage 2 performance in English and Mathematics
This report considers children\u27s educational attainment in English and mathematics at the end of primary school (age 11). Children\u27s educational attainment in English and mathematics was derived from their national Key Stage 2 assessments. The analyses have considered the child\u27s level of Key Stage 2 attainment in terms of the effects of child, family, home environment and preschool experience variables as well as the child\u27s ability at the start of primary school
Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas
Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of
galaxies. It is normally assumed that, following the merger of two massive
galaxies, a SMBH binary will form, shrink due to stellar or gas dynamical
processes and ultimately coalesce by emitting a burst of gravitational waves.
However, so far it has not been possible to show how two SMBHs bind during a
galaxy merger with gas due to the difficulty of modeling a wide range of
spatial scales. Here we report hydrodynamical simulations that track the
formation of a SMBH binary down to scales of a few light years following the
collision between two spiral galaxies. A massive, turbulent nuclear gaseous
disk arises as a result of the galaxy merger. The black holes form an eccentric
binary in the disk in less than a million years as a result of the
gravitational drag from the gas rather than from the stars.Comment: Accepted for publication in Science, 40 pages, 7 figures,
Supplementary Information include
Neutrino Fluxes from Active Galaxies: a Model-Independent Analysis
There are tantalizing hints that jets, powered by supermassive black holes at
the center of active galaxies, are true cosmic proton accelerators. They
produce photons of TeV energy, possible higher, and may be the enigmatic source
of the highest energy cosmic rays. Photoproduction of neutral pions by
accelerated protons on UV light is the source of the highest energy photons, in
which most of the bolometric luminosity of the galaxy may be emitted. The case
that proton beams power active galaxies is, however, far from conclusive.
Neutrinos from the decay of charged pions represent an uncontrovertible
signature for the proton induced cascades. We show that their flux can be
estimated by model-independent methods, based on dimensional analysis and
textbook particle physics. Our calculations also demonstrate why different
models for the proton blazar yield very similar results for the neutrino flux,
consistent with the ones obtained here.Comment: Latex 2.09 with epsf.sty. 12 pages, 2 postscript figures. Compressed
postscript version of paper with figures also available soon at
http://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-982.ps.Z or at
ftp://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-982.ps.
A PCA-Based Framework for Determining Remotely Sensed Geological Surface Orientations and Their Statistical Quality
The orientations of planar rock layers are fundamental to our understanding of structural geology and stratigraphy. Remote sensing platforms including satellites, unmanned aerial vehicles, and Light Detection and Ranging scanners are increasingly used to build three-dimensional models of structural features on Earth and other planets. Remotely gathered orientation measurements are straightforward to calculate but subject to uncertainty inherited from input data, differences in viewing geometry, and the plane-fitting process, complicating geological interpretation. Here, we improve upon the present state of the art by developing a generalized means for computing and reporting errors in strike-dip measurements from remotely sensed data. We outline a general framework for representing the error space of uncertain orientations in Cartesian and spherical coordinates and develop a principal component analysis (PCA) regression method, which captures statistical errors independent of viewing geometry and input data structure. We also introduce graphical techniques to visualize the uniqueness and quality of orientation measurements and a process to increase statistical power by jointly fitting bedding planes under the assumption of parallel stratigraphy. These new techniques are validated by comparison of field-gathered orientation measurements with those derived from minimally processed satellite imagery of the San Rafael Swell, Utah, and unmanned aerial vehicle imagery from the Naukluft Mountains, Namibia. We provide software packages supporting planar fitting and visualization of error distributions. This method increases the precision and comparability of structural measurements gathered using a new generation of remote sensing techniques
A spectropolarimetric view on the nature of the peculiar Type I SN 2005hk
We report two spectropolarimetric observations of SN 2005hk, which is a close
copy of the "very peculiar" SN 2002cx, showing low peak luminosity, slow
decline, high ionization near peak and an unusually low expansion velocity of
only about 7,000 km s^-1. Further to the data presented by Chornock et al.,
(2006), at -4 days before maximum, we present data of this object taken on 9
November 2005 (near maximum) and 23 November (+ two weeks) that show the
continuum and most of the spectral lines to be polarized at levels of about
0.2-0.3%. At both epochs the data corresponds to the Spectropolarimetric Type
D1. The general low level of line polarization suggests that the line forming
regions for most species observed in the spectrum have a similar shape to that
of the photosphere, which deviates from a spherical symmetry by <10%. In
comparison with spectropolarimetry of Type Ia and Core-collapse SNe at similar
epochs, we find that the properties of SN 2005hk are most similar to those of
Type Ia SNe. In particular, we find the low levels of continuum and line
polarization to indicate that the explosion mechanism is approximately
spherical, with homogeneous ejecta (unlike the chemically segregated ejecta of
CCSNe). We discuss the possibility that SN 2005hk was the result of the pure
deflagration of a white dwarf and note the issues concerning this
interpretation.Comment: ApJ accepted, uses emulateapj, 16 pages, 10 figures, figures 3 and 4
update
- …