2,812 research outputs found
Monophyly of brachiopods and phoronids: reconciliation of molecular evidence with Linnaean classification (the subphylum Phoroniformea nov.)
Molecular phylogenetic analyses of aligned 18S rDNA gene sequences from articulate and inarticulate brachiopods representing all major extant lineages, an enhanced set of phoronids and several unrelated protostome taxa, confirm previous indications that in such data, brachiopod and phoronids form a well-supported clade that (on previous evidence) is unambiguously affiliated with protostomes rather than deuterostomes. Within the brachiopod-phoronid clade, an association between phoronids and inarticulate brachiopods is moderately well supported, whilst a close relationship between phoronids and craniid inarticulates is weakly indicated. Brachiopod-phoronid monophyly is reconciled with the most recent Linnaean classification of brachiopods by abolition of the phylum Phoronida and rediagnosis of the phylum Brachiopoda to include tubiculous, shell-less forms. Recognition that brachiopods and phoronids are close genealogical allies of protostome phyla such as molluscs and annelids, but are much more distantly related to deuterostome phyla such as echinoderms and chordates, implies either (or both) that the morphology and ontogeny of blastopore, mesoderm and coelom formation have been widely misreported or misinterpreted, or that these characters have been subject to extensive homoplasy. This inference, if true, undermines virtually all morphology-based reconstructions of phylogeny made during the past century or more
Assessing Medical Room Behavior During Infants’ Painful Medical Procedures: The Measure of Adult and Infant Soothing and Distress (MAISD)
This study evaluated the Measure of Adult and Infant Soothing and Distress (MAISD) for examining infant, parent, and nurse behavior during infants’ immunizations. Videotapes of 62 infants, parents, and nurses during immunizations were coded. Concurrent validity and reliability for the MAISD were demonstrated. The scale revealed that infants displayed predominately distress, and adults exhibited primarily reassurance. Parents’ and nurses’ distractions were positively related to infants’ engaging in distraction, and parents’ and nurses’ reassurance was positively associated with infant distress. There appear to be avenues in which to intervene to teach parents and nurses how to best behave to help infants during their painful medical events
Physical Results from Unphysical Simulations
We calculate various properties of pseudoscalar mesons in partially quenched
QCD using chiral perturbation theory through next-to-leading order. Our results
can be used to extrapolate to QCD from partially quenched simulations, as long
as the latter use three light dynamical quarks. In other words, one can use
unphysical simulations to extract physical quantities - in this case the quark
masses, meson decay constants, and the Gasser-Leutwyler parameters L_4-L_8. Our
proposal for determining L_7 makes explicit use of an unphysical (yet
measurable) effect of partially quenched theories, namely the double-pole that
appears in certain two-point correlation functions. Most of our calculations
are done for sea quarks having up to three different masses, except for our
result for L_7, which is derived for degenerate sea quarks.Comment: 26 pages, 12 figures (discussion on discretization errors at end of
sec. IV clarified; minor improvements in presentation; results unchanged
Topics in Chiral Perturbation Theory
I consider some selected topics in chiral perturbation theory (CHPT). For the
meson sector, emphasis is put on processes involving pions in the isospin zero
S-wave which require multi-loop calculations. The advantages and shortcomings
of heavy baryon CHPT are discussed. Some recent results on the structure of the
baryons are also presented.Comment: 30 pp, TeX, Review talk, Third Workshop on High Energy Particle
Physics (WHEPP III), Madras, India, January 1994. 7 figures available upon
request. CRN--94/0
Star formation in M33: Spitzer photometry of discrete sources
Combining the relative vicinity of the Local Group spiral galaxy M33 with the
Spitzer images, we investigate the properties of infrared (IR) emission sites
and assess the reliability of the IR emission as a star formation tracer. The
mid- and far-IR emission of M33 was obtained from IRAC and MIPS images from the
Spitzer archive. We compared the photometric results for several samples of
three known types of discrete sources (HII regions, supernovae remnants and
planetary nebulae) with theoretical diagnostic diagrams, and derived the
spectral energy distribution (from 3.6 to 24 micron) of each type of object.
Moreover, we generated a catalogue of 24 micron sources and inferred their
nature from the observed and theoretical colours of the known type sources. We
estimated the star formation rate in M33 both globally and locally, from the IR
emission and from the Halpha emission line. The colours of the typical IR
emissions of HII regions, supernovae remnants and planetary nebulae are
continuous among the different samples, with overlapping regions in the
diagnostic diagrams. The comparison between the model results and the colours
of HII regions indicates a dusty envelope at relatively high temperatures ~600
K, and moderate extinction Av < 10. The 24 micron sources IR colours follow the
regions observationally defined by the three classes of known objects but the
majority of them represent HII regions. The derived total IR luminosity
function is in fact very similar to the HII luminosity function observed in the
Milky Way and in other late type spirals. Even though our completeness limit is
5x10^37 ergs s-1, in low density regions we are able to detect sources five
times fainter than this, corresponding to the faintest possible HII region.
[abridged]Comment: 19 pages, 18 figures (low resolution), accepted for publication by
A&A; corrected typo
An assessment of the screening method to evaluate vaccine effectiveness: the case of 7-valent pneumococcal conjugate vaccine in the United States.
The screening method, which employs readily available data, is an inexpensive and quick means of estimating vaccine effectiveness (VE). We compared estimates of effectiveness of heptavalent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease (IPD) using the screening and case-control methods. Cases were children aged 19-35 months with pneumococcus isolated from normally sterile sites residing in Active Bacterial Core surveillance areas in the United States. Case-control VE was estimated for 2001-2004 by comparing the odds of vaccination among cases and community controls. Screening-method VE for 2001-2009 was estimated by comparing the proportion of cases vaccinated to National Immunization Survey-derived coverage among the general population. To evaluate the plausibility of screening-method VE findings, we estimated attack rates among vaccinated and unvaccinated persons. We identified 1,154 children with IPD. Annual population PCV7 coverage with ≥1 dose increased from 38% to 97%. Case-control VE for ≥1 dose was estimated as 75% against all-serotype IPD (annual range: 35-83%) and 91% for PCV7-type IPD (annual range: 65-100%). By the screening method, the overall VE was 86% for ≥1 dose (annual range: -240-70%) against all-serotype IPD and 94% (annual range: 62-97%) against PCV7-type IPD. As cases of PCV7-type IPD declined during 2001-2005, estimated attack rates for all-serotype IPD among vaccinated and unvaccinated individuals became less consistent than what would be expected with the estimated effectiveness of PCV7. The screening method yields estimates of VE that are highly dependent on the time period during which it is used and the choice of outcome. The method should be used cautiously to evaluate VE of PCVs
What does a change in the quark condensate say about restoration of chiral symmetry in matter?
The contribution of nucleons to the quark condensate in nuclear matter
includes a piece of first order in , arising from the contribution of
low-momentum virtual pions to the sigma commutator. Chiral symmetry
requires that no term of this order appears in the interaction. The mass
of a nucleon in matter thus cannot depend in any simple way on the quark
condensate alone. More generally, pieces of the quark condensate that arise
from low-momentum pions should not be associated with partial restoration of
chiral symmetry.Comment: 9 pages (RevTeX). Definition of effective mass changed; numerical
value of leading nonanalytic term corrected, along with various misprint
The pion photoproduction in the \Delta(1232) region
We investigate the pion photoproduction in the \Delta(1232) region in the
framework of an effective Lagrangian including pions, nulceon and \Delta(1232).
We work to third order in a small scale expansion with both and
treated as light scales. We note that in the region,
straightward power counting breaks as the amplitudes become very large, to deal
with this problem, we suggest that the appropriate way to compare theoretical
calculations with experimental data is via weighted integrals of the amplitudes
through the region.Comment: 34 pages and 5 figures,new counterterms arr adde
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