7,319 research outputs found
Sharing the burden : on the division of parental care and vocalizations during incubation
In species with biparental care, individuals only have to pay the costs for their own parental investment, whereas the contribution of their partner comes for free. Each parent hence benefits if its partner works harder, creating an evolutionary conflict of interest. How parents resolve this conflict and how they achieve the optimal division of parental tasks often remains elusive. In this study, we investigated whether lesser black-backed gulls (Larus fuscus) divide parental care during incubation equally and whether this correlates with the extent of vocalizations between pair-members during incubation. We then investigated whether pairs showing more evenly distributed incubation behavior had a higher reproductive success. To this end, we recorded incubation behavior and vocalizations for 24-h time periods. Subsequently, we experimentally increased or decreased brood sizes in order to manipulate parental effort, and followed offspring development from hatching till fledging. Although incubation bouts were, on average, slightly longer in females, patterns varied strongly between pairs, ranging from primarily female incubation over equal sex contributions to male-biased incubation. Pairs contributing more equally to incubation vocalized more during nest relief and had a higher reproductive output when brood sizes were experimentally increased. Thus, vocalizations and a more equal division of parental care during incubation may facilitate higher levels of care during the nestling period, as suggested by a greater reproductive success when facing high brood demand, or they indicate pair quality
Status of the ILC Main Linac BPM R&D
An introduction and the status of R&D activities for a high-resolution,
"cold" beam position monitor (BPM) and the related read-out electronics are
discussed. Two different BPM detector concepts, to be attached to the SC
quadrupole and located inside the ILC cryomodule, are currently under
investigation: A resonant dipole-mode cavity-style BPM pickup, developed at
Fermilab, and a re-entrant resonant coaxial waveguide BPM, designed by
CEA-Saclay. While the 1.5 GHz dipole-mode cavity BPM is still in the R&D phase,
the re-entrant BPM has already passed first beam tests, including its read-out
system. Furthermore, the LAPP group is developing radiation tolerant digital
read-out systems, which are tested at the CLIC test facility (CTF).Comment: LCWS / ILC08 conference contribution, 6 pages, 6 figure
Diffuse interstellar bands {\lambda}5780 and {\lambda}5797 in the Antennae Galaxy as seen by MUSE
ABRIDGED: Diffuse interstellar bands (DIBs) are faint spectral absorption
features of unknown origin. Research on DIBs beyond the Local Group (LG) will
surely blossom in the era of the ELTs. A possibility that needs to be explored
is the use of integral field spectrographs. We do so by using MUSE data for the
Antennae Galaxy, the closest major galaxy merger. High S-to-N spectra were
created by co-adding the signal of many spatial elements. The emission of the
underlying stellar population was modeled using STARLIGHT. To our knowledge, we
have derived the first maps for the DIBs at l5780 and l5797 in galaxies outside
the LG. The l5780 DIB was detected in an area of ~0.6 arcmin2, corresponding to
a linear scale of ~25 kpc2. This region was sampled using >200 independent
lines of sight. The DIB l5797 was detected in >100 independent lines of sight.
Both DIBs are associated with a region with high emission in the HI 21 cm line,
implying a connection between atomic gas and DIBs, as the correlations for the
Milky Way also suggest. Conversely, there is mild spatial association between
the two DIBs and the molecular gas, in agreement with results for our Galaxy
that indicate a lack of correlation between DIBs and molecular gas. The overall
structure for the DIB strength distribution and extinction are comparable.
Within the system, the l5780 DIB clearly correlates with the extinction. Both
DIBs follow the relationship between equivalent width and reddening when data
for several galaxies are considered. Unidentified Infrared emission Bands
(UIBs, likely caused by PAHs) and the l5780 and l5797 DIBs show similar but not
identical spatial distributions. We attribute the differences to extinction
effects without necessarily implying a radically different nature of the
respective carriers. The results illustrate the enormous potential of integral
field spectrographs for extragalactic DIB research.Comment: 12 pages, 13 figures, accepted by Astronomy & Astrophysics; version
corrected by English edito
Bernard Yarnton Mills 1920-2011
Bernie Mills is remembered globally as an influential pioneer in the evolving
field of radio astronomy. His contributions with the 'Mills Cross' at the CSIRO
Division of Radiophysics and later at the University of Sydney's School of
Physics and the development of the Molonglo Observatory Synthesis Telescope
(MOST) were widely recognised as astronomy evolved in the years 1948-1985 and
radio astronomy changed the viewpoint of the astronomer as a host of new
objects were discovered
A Wire Position Monitor System for the 1.3 GHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator
The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab
building is currently under RF commissioning. Among other diagnostics systems,
the transverse position of the helium gas return pipe with the connected 1.3
GHz SRF accelerating cavities is measured along the ~15 m long module using a
stretched-wire position monitoring system. An overview of the wire position
monitor system technology is given, along with preliminary results taken at the
initial module cool down, and during further testing. As the measurement system
offers a high resolution, we also discuss options for use as a vibration
detector.Comment: 4 pp. 15th International Conference on RF Superconductivity
(SRF2011). 25-29 Jul 2011. Chicago, Illinois, US
High Resolution BPM Upgrade for the ATF Damping Ring at KEK
A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility
(ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC
collaboration under the umbrella of the global ILC R&D effort. The upgrade
consists of a high resolution, high reproducibility read-out system, based on
analog and processing, and also implements a new automatic gain error
correction schema. The technical concept and realization as well as results of
beam studies are presented.Comment: 3 pp. 10th European Workshop on Beam Diagnostics and Instrumentation
for Particle Accelerators DIPAC 2011, 16-18 May 2011. Hamburg, German
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