1,353 research outputs found
Behavior Associated with Feeding in Captive African and Asian Elephants
Elephants\u27 use of their trunks during feeding in captivity is described. African and Asian elephants differ not only in trunk morphology but also in trunk behavior. African elephants pick up objects using a pinch while Asians rely mostly on a grasp. Asians normally use their feet to secure objects while Africans use their tusks. The first documented case of Africans using their feet is reported. Laterality or handedness is also reported for the first time in elephants. A survey of several zoos and circuses showed this phenomenon to be widespread in captivity. A female African elephant who was intensively studied showed lateral preferences for many different components of her feeding behavior
Sterile neutrino dark matter: A tale of weak interactions in the strong coupling epoch
We perform a detailed study of the weak interactions of standard model
neutrinos with the primordial plasma and their effect on the resonant
production of sterile neutrino dark matter. Motivated by issues in cosmological
structure formation on small scales, and reported X-ray signals that could be
due to sterile neutrino decay, we consider keV-scale sterile neutrinos.
Oscillation-driven production of such sterile neutrinos occurs at temperatures
MeV, where we study two significant effects of weakly charged
species in the primordial plasma: (1) the redistribution of an input lepton
asymmetry; (2) the opacity for active neutrinos. We calculate the
redistribution analytically above and below the quark-hadron transition, and
match with lattice QCD calculations through the transition. We estimate
opacities due to tree level processes involving leptons and quarks above the
quark-hadron transition, and the most important mesons below the transition. We
report final sterile neutrino dark matter phase space densities that are
significantly influenced by these effects, and yet relatively robust to
remaining uncertainties in the nature of the quark-hadron transition. We also
provide transfer functions for cosmological density fluctuations with cutoffs
at , that are relevant to galactic structure
formation.Comment: 28 pages, 11 figures, code repository at
https://github.com/ntveem/sterile-d
Benchmarking quantum control methods on a 12-qubit system
In this letter, we present an experimental benchmark of operational control
methods in quantum information processors extended up to 12 qubits. We
implement universal control of this large Hilbert space using two complementary
approaches and discuss their accuracy and scalability. Despite decoherence, we
were able to reach a 12-coherence state (or 12-qubits pseudo-pure cat state),
and decode it into an 11 qubit plus one qutrit labeled observable pseudo-pure
state using liquid state nuclear magnetic resonance quantum information
processors.Comment: 11 pages, 4 figures, to be published in PR
Retrospective analysis of the impact of respiratory motion in treatment margins for frameless lung SBRT based on respiratory-correlated CBCT data-sets.
To investigate the impact of respiratory motion in the treatment margins for lung SBRT frameless treatments and to validate our treatment margins using 4D CBCT data analysis.
Two hundred and twenty nine fractions with early stage NSCLC were retrospectively analyzed. All patients were treated in frameless and free breathing conditions. The treatment margins were calculated according to van Herk equation in Mid-Ventilation. For each fraction, three 4D CBCT scans, pre- and postcorrection, and posttreatment, were acquired to assess target baseline shift, target localization accuracy and intra-fraction motion errors. A bootstrap analysis was performed to assess the minimum number of patients required to define treatment margins.
The retrospectively calculated target-baseline shift, target localization accuracy and intra-fraction motion errors agreed with the literature. The best tailored margins to our cohort of patients were retrospectively computed and resulted in agreement with already published data. The bootstrap analysis showed that fifteen patients were enough to assess treatment margins.
The treatment margins applied to our patient's cohort resulted in good agreement with the retrospectively calculated margins based on 4D CBCT data. Moreover, the bootstrap analysis revealed to be a promising method to verify the reliability of the applied treatment margins for safe lung SBRT delivery
UK science press officers, professional vision and the generation of expectations
Science press officers can play an integral role in helping promote expectations and hype about biomedical research. Using this as a starting point, this article draws on interviews with 10 UK-based science press officers, which explored how they view their role as science reporters and as generators of expectations. Using Goodwin’s notion of ‘professional vision’, we argue that science press officers have a specific professional vision that shapes how they produce biomedical press releases, engage in promotion of biomedical research and make sense of hype. We discuss how these insights can contribute to the sociology of expectations, as well as inform responsible science communication.This project was funded by the Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034)
Targeted rapid amplification of cDNA ends (T-RACE)—an improved RACE reaction through degradation of non-target sequences
Amplification of the 5′ ends of cDNA, although simple in theory, can often be difficult to achieve. We describe a novel method for the specific amplification of cDNA ends. An oligo-dT adapter incorporating a dUTP-containing PCR primer primes first-strand cDNA synthesis incorporating dUTP. Using the Cap finder approach, another distinct dUTP containing adapter is added to the 3′ end of the newly synthesized cDNA. Second-strand synthesis incorporating dUTP is achieved by PCR, using dUTP-containing primers complimentary to the adapter sequences incorporated in the cDNA ends. The double-stranded cDNA-containing dUTP serves as a universal template for the specific amplification of the 3′ or 5′ end of any gene. To amplify the ends of cDNA, asymmetric PCR is performed using a single gene-specific primer and standard dNTPs. The asymmetric PCR product is purified and non-target transcripts containing dUTP degraded by Uracil DNA glycosylase, leaving only those transcripts produced during the asymmetric PCR. Subsequent PCR using a nested gene-specific primer and the 3′ or 5′ T-RACE primer results in specific amplification of cDNA ends. This method can be used to specifically amplify the 3′ and 5′ ends of numerous cDNAs from a single cDNA synthesis reaction
PFC, codages et représentations : la question du schwa
L’objectif de cet article est de faire le point sur le programme de recherche PFC (« Phonologie du français contemporain : usages, variétés et structure »), plus de quinze ans après son lancement et d’illustrer le travail mené dans ce cadre par la question du schwa, phénomène bien connu dans le domaine de la variation phonologique et central à la phonologie du français. Après avoir brièvement présenté le programme, nous abordons la question du schwa en français et expliquons son traitement dans PFC. Nous illustrons ensuite le travail effectué en nous penchant tout d’abord sur les variétés méridionales, que nous opposons aux variétés septentrionales, avant d’aborder la question du schwa dans les variétés suisses romandes.In this paper, we present the research programme “Phonology of Contemporary French : usage, varieties and structure” (PFC). After more than 15 years of existence, the PFC corpus has become a reference in the field of oral French. The methodology adopted in the programme is then illustrated through the phenomenon of schwa, which is central to the phonology of French and one of the foci of the PFC venture. First, we examine the behaviour of schwa in the Southern varieties of French (vs. Northern varieties) and then we present an experimental study on schwa in three varieties of Swiss French
The mass ratio distribution of B-type visual binaries in the Sco OB2 association
The sample of 115 B-type stars in Sco OB2 association is examined for
existence of visual companions with ADONIS near-infrared adaptive optics system
and coronograph in J and K bands. Practically all components in the separation
range 0.3"-6" (45-900 A.U.) were detected, with magnitudes down to K=16. The K
and J-K photometry of primaries and differential photometry and astrometry of
96 secondaries are presented. Ten secondaries are new physical components, as
inferred from photometric and statistical criteria, while remaining are faint
background stars. After small correction for detection incompleteness and
conversion of fluxes into masses, an unbiased distribution of the components
mass ratio q is derived. The power law f(q)\propto q^{-0.5} fits well the
observations, whereas a q^{-1.8} distribution which corresponds to random
pairing of stars is rejected. The companion star fraction is 0.20 +- 0.04 per
decade of separation, comparable to the highest measured binary fraction among
low-mass PMS stars and ~1.6 times higher than the binary fraction of low-mass
dwarfs in solar neighborhood and open clusters in the same separation range.Comment: 12 pages, submitted to Astronomy & Astrophysic
High temperature superconducting infrared imaging satellite
A low earth orbiting platform for an infrared (IR) sensor payload is examined based on the requirements of a Naval Research Laboratory statement of work. The experiment payload is a 1.5-meter square by 0.5-meter high cubic structure equipped with the imaging system, radiators, and spacecraft mounting interface. The orbit is circular at 509 km (275 nmi) altitude and 70 deg. inclination. The spacecraft is three-axis stabilized with pointing accuracy of plus or minus 0.5 deg. in each axis. The experiment payload requires two 15-minute sensing periods over two contiguous orbit periods for 30 minutes of sensing time per day. The spacecraft design is presented for launch via a Delta 2 rocket. Subsystem designs include attitude control, propulsion, electric power, telemetry, tracking and command, thermal design, structure, and cost analysis
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