257 research outputs found
Movement of Coconut Crabs, Birgus latro, in a Rainforest Habitat in Vanuatu
Patterns of movement in the coconut crab, Birgus latro (L.), were
studied using mark-recapture and radio-tracking techniques at a number of
sites in the rainforest regions of eastern Santo, Republic of Vanuatu (South
Pacific). Movement was assessed both for crabs caught and released in one place
(indigenous) and for crabs caught and then released at a new location
(introduced). Recapture rates in eastern Santo were very small ( < I%), whereas
on the small islet sites (area <2 ha) the rate approached 20%. There were no
significant relationships between distance moved and either time at liberty or
size of the individuals for introduced crabs. But for indigenous crabs, size of
individual was negatively correlated with distance moved. Recapture rates of
introduced and indigenous crabs were similar , but introduced crabs moved
significantly further from their point of release. Almost all radio-tagged crabs
moved from their point of release; smaller crabs tended to move further. On
eastern Santo, only two of five radio-tagged crabs were located again ; both had
moved over 250-m away from their release point. On the islet sites, all radiotagged
crabs were found again at least once; some of these returned to a number
of different sites, indicating that B. latro seems to be able to home to particular
locations. Nonetheless, dispersal of animals from an area, at least after handling,
is a common feature
Asteroseismology across the HR diagram
High precision spectroscopy provides essential information necessary to fully
exploit the opportunity of probing the internal structure of stars using
Asteroseismology. In this work we discuss how Asteroseismology combined with
High Precision Spectroscopy can establish a detailed view on stellar structure
and evolution of stars across the HR diagramme.Comment: 6 pages, 2 figures - to appear in Precision Spectroscopy in
Astrophysics, (Eds) L. Pasquini, M. Romaniello, N.C. Santos, and A. Correia,
ESO Astrophysics Symposia, 200
Prospects for asteroseismology
The observational basis for asteroseismology is being dramatically
strengthened, through more than two years of data from the CoRoT satellite, the
flood of data coming from the Kepler mission and, in the slightly longer term,
from dedicated ground-based facilities. Our ability to utilize these data
depends on further development of techniques for basic data analysis, as well
as on an improved understanding of the relation between the observed
frequencies and the underlying properties of the stars. Also, stellar modelling
must be further developed, to match the increasing diagnostic potential of the
data. Here we discuss some aspects of data interpretation and modelling,
focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar
modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space
Sci., in the press Revision: correcting abscissa labels on Figs 1 and
Theory of Stellar Oscillations
In recent years, astronomers have witnessed major progresses in the field of
stellar physics. This was made possible thanks to the combination of a solid
theoretical understanding of the phenomena of stellar pulsations and the
availability of a tremendous amount of exquisite space-based asteroseismic
data. In this context, this chapter reviews the basic theory of stellar
pulsations, considering small, adiabatic perturbations to a static, spherically
symmetric equilibrium. It starts with a brief discussion of the solar
oscillation spectrum, followed by the setting of the theoretical problem,
including the presentation of the equations of hydrodynamics, their
perturbation, and a discussion of the functional form of the solutions.
Emphasis is put on the physical properties of the different types of modes, in
particular acoustic (p-) and gravity (g-) modes and their propagation cavities.
The surface (f-) mode solutions are also discussed. While not attempting to be
comprehensive, it is hoped that the summary presented in this chapter addresses
the most important theoretical aspects that are required for a solid start in
stellar pulsations research.Comment: Lecture presented at the IVth Azores International Advanced School in
Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars
and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta,
Azores Islands, Portugal in July 201
Investigating Genres and Perspectives in HCI Research on the Home
The home and domestic experiences have been studied from multiple points of view and disciplines, with an array of methodologies in the past twenty-five years in HCI. Given the attention to the home and the volume of research, what further areas of research might there be? Based on a critical analysis of 121 works on the topic, we present seven genres of domestic technology research in HCI: social routines in the home, ongoing domestic practices, the home as a testing ground, smart homes, contested values of a home, the home as a site for interpretation, and speculative visions of the home. We articulate dominant research perspectives in HCI, and we offer two complementary perspectives about how to investigate the domestic experience in future research: the material perspective and the first person perspective
Influence of confinement on the orientational phase transitions in the lamellar phase of a block copolymer melt under shear flow
In this work we incorporate some real-system effects into the theory of
orientational phase transitions under shear flow (M. E. Cates and S. T. Milner,
Phys. Rev. Lett. v.62, p.1856 (1989) and G. H. Fredrickson, J. Rheol. v.38,
p.1045 (1994)). In particular, we study the influence of the shear-cell
boundaries on the orientation of the lamellar phase. We predict that at low
shear rates the parallel orientation appears to be stable. We show that there
is a critical value of the shear rate at which the parallel orientation loses
its stability and the perpendicular one appears immediately below the spinodal.
We associate this transition with a crossover from the fluctuation to the
mean-field behaviour. At lower temperatures the stability of the parallel
orientation is restored. We find that the region of stability of the
perpendicular orientation rapidly decreases as shear rate increases. This
behaviour might be misinterpreted as an additional perpendicular to parallel
transition recently discussed in literature.Comment: 25 pages, 4 figures, submitted to Phys. Rev.
Lattice Calculation of Heavy-Light Decay Constants with Two Flavors of Dynamical Quarks
We present results for , , , and their ratios in
the presence of two flavors of light sea quarks (). We use Wilson light
valence quarks and Wilson and static heavy valence quarks; the sea quarks are
simulated with staggered fermions. Additional quenched simulations with
nonperturbatively improved clover fermions allow us to improve our control of
the continuum extrapolation. For our central values the masses of the sea
quarks are not extrapolated to the physical , masses; that is, the
central values are "partially quenched." A calculation using "fat-link clover"
valence fermions is also discussed but is not included in our final results. We
find, for example,
MeV, , MeV, and , where in each case the first error is
statistical and the remaining three are systematic: the error within the
partially quenched approximation, the error due to the missing strange
sea quark and to partial quenching, and an estimate of the effects of chiral
logarithms at small quark mass. The last error, though quite significant in
decay constant ratios, appears to be smaller than has been recently suggested
by Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other
lattice computations to date, the lattice quark masses are not very light
and chiral log effects may not be fully under control.Comment: Revised version includes an attempt to estimate the effects of chiral
logarithms at small quark mass; central values are unchanged but one more
systematic error has been added. Sections III E and V D are completely new;
some changes for clarity have also been made elsewhere. 82 pages; 32 figure
FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium
Background:Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.
Methods:Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.
Results:Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95 confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2.
Conclusion:Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2. Ă© 2014 Cancer Research UK
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
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