332 research outputs found
Generalisation of early learned tutor song preferences in female zebra finches (Taeniopygia guttata)
Animal science
Foraging zebra finches (Taeniopygia guttata) are public information users rather than conformists
Animal science
Effects of cortical FoxP1 knockdowns on learned song preference in female zebra finches
The search for molecular underpinnings of human vocal communication has focused on genes encoding forkhead-box transcription factors, as rare disruptions of FOXP1, FOXP2, and FOXP4 have been linked to disorders involving speech and language deficits. In male songbirds, an animal model for vocal learning, experimentally altered expression levels of these transcription factors impair song production learning. The relative contributions of auditory processing, motor function or auditory-motor integration to the deficits observed after different FoxP manipulations in songbirds are unknown. To examine the potential effects on auditory learning and development, we focused on female zebra finches (Taeniopygia guttata) that do not sing but develop song memories, which can be assayed in operant preference tests. We tested whether the relatively high levels of FoxP1 expression in forebrain areas implicated in female song preference learning are crucial for the development and/or maintenance of this behavior. Juvenile and adult female zebra finches received FoxP1 knockdowns targeted to HVC (proper name) or to the caudomedial mesopallium (CMM). Irrespective of target site and whether the knockdown took place before (juveniles) or after (adults) the sensitive phase for song memorization, all groups preferred their tutor’s song. However, adult females with FoxP1 knockdowns targeted at HVC showed weaker motivation to hear song and weaker song preferences than sham-treated controls, while no such differences were observed after knockdowns in CMM or in juveniles. In summary, FoxP1 knockdowns in the cortical song nucleus HVC were not associated with impaired tutor song memory but reduced motivation to actively request tutor songs.NWOAnimal science
Evidence for Pre-Existing Dust in the Bright Type IIn SN 2010jl
SN 2010jl was an extremely bright, Type IIn SNe which showed a significant IR
excess no later than 90 days after explosion. We have obtained Spitzer 3.6 and
4.5 \mum and JHK observations of SN 2010jl \sim90 days post explosion. Little
to no reddening in the host galaxy indicated that the circumstellar material
lost from the progenitor must lie in a torus inclined out of the plane of the
sky. The likely cause of the high mid-IR flux is the reprocessing of the
initial flash of the SN by pre-existing circumstellar dust. Using a 3D Monte
Carlo Radiative Transfer code, we have estimated that between 0.03-0.35 Msun of
dust exists in a circumstellar torus around the SN located 6 \times 10 ^17 cm
away from the SN and inclined between 60-80\cdot to the plane of the sky. On
day 90, we are only seeing the illumination of approximately 5% of this torus,
and expect to see an elevated IR flux from this material up until day \sim 450.
It is likely this dust was created in an LBV-like mass loss event of more than
3 Msun, which is large but consistent with other LBV progenitors such as {\eta}
Carinae.Comment: Accepted in A
Multihospital Outbreak of Clostridium difficile Infection, Cleveland, Ohio, USA
To determine whether a multihospital Clostridium difficile outbreak was associated with epidemic strains and whether use of particular fluoroquinolones was associated with increased infection rates, we cultured feces from C. difficile–infected patients. Use of fluoroquionolones with enhanced antianaerobic activity was not associated with increased infection rates
High heart rate associated early repolarization causes J‐waves in both zebra finch and mouse
Animal science
Cold Dust in Three Massive Evolved Stars in the LMC
Massive evolved stars can produce large amounts of dust, and far-infrared
(IR) data are essential for determining the contribution of cold dust to the
total dust mass. Using Herschel, we search for cold dust in three very dusty
massive evolved stars in the Large Magellanic Cloud: R71 is a Luminous Blue
Variable, HD36402 is a Wolf-Rayet triple system, and IRAS05280-6910 is a red
supergiant. We model the spectral energy distributions using radiative transfer
codes and find that these three stars have mass-loss rates up to 10^-3 solar
masses/year, suggesting that high-mass stars are important contributors to the
life-cycle of dust. We found far-IR excesses in two objects, but these excesses
appear to be associated with ISM and star-forming regions. Cold dust (T < 100
K) may thus not be an important contributor to the dust masses of evolved
stars.Comment: accepted to A&A as part of the Herschel first results special issu
The evolutionary state of Miras with changing pulsation periods
Context: Miras are long-period variables thought to be in the asymptotic
giant branch (AGB) phase of evolution. In about one percent of known Miras, the
pulsation period is changing. It has been speculated that this changing period
is the consequence of a recent thermal pulse in these stars. Aims: We aim to
clarify the evolutionary state of these stars, and to determine in particular
whether or not they are in the thermally-pulsing (TP-)AGB phase. Methods: One
important piece of information that has been neglected so far when determining
the evolutionary state is the presence of the radio-active s-process element
technetium (Tc). We obtained high-resolution, high signal-to-noise-ratio
optical spectra of a dozen prominent Mira variables with changing pulsation
period to search for this indicator of TPs and dredge-up. We also use the
spectra to measure lithium (Li) abundances. Furthermore, we establish the
evolutionary states of our sample stars by means of their present-day periods
and luminosities. Results: Among the twelve sample stars observed in this
programme, five were found to show absorption lines of Tc. BH Cru is found to
be a carbon-star, its period increase in the past decades possibly having
stopped by now. We report a possible switch in the pulsation mode of T UMi from
Mira-like to semi-regular variability in the past two years. R Nor, on the
other hand, is probably a fairly massive AGB star, which could be true for all
meandering Miras. Finally, we assign RU Vul to the metal-poor thick disk with
properties very similar to the short-period, metal-poor Miras. Conclusions: We
conclude that there is no clear correlation between period change class and Tc
presence. The stars that are most likely to have experienced a recent TP are BH
Cru and R Hya, although their rates of period change are quite different.Comment: 11 pages, 7 figures, 2 tables; accepted for publication in A&
Expanding the set of rhodococcal Baeyer–Villiger monooxygenases by high-throughput cloning, expression and substrate screening
To expand the available set of Baeyer–Villiger monooxygenases (BVMOs), we have created expression constructs for producing 22 Type I BVMOs that are present in the genome of Rhodococcus jostii RHA1. Each BVMO has been probed with a large panel of potential substrates. Except for testing their substrate acceptance, also the enantioselectivity of some selected BVMOs was studied. The results provide insight into the biocatalytic potential of this collection of BVMOs and expand the biocatalytic repertoire known for BVMOs. This study also sheds light on the catalytic capacity of this large set of BVMOs that is present in this specific actinomycete. Furthermore, a comparative sequence analysis revealed a new BVMO-typifying sequence motif. This motif represents a useful tool for effective future genome mining efforts.
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