1,580 research outputs found
Quand l'information échappe à ses créateurs : le cas de l'artificialisation des terres agricoles en Languedoc-Roussillon
International audienceThis article aims to describe how the quantification of a phenomenon in relation to a specific worldview spreads and is distorted. This project has been supported by a regional public authority in Languedoc-Roussillon (France), and consisted in the production of information so to quantify and qualify the farmland decrease due to urban sprawl. The paper is based on Latour's actor-network theory; it characterizes the process of enrolment, and the development of dissidences. Identifying contradictory logics and dissidences help questioning the complexity of ‘closing the black-box' regarding information production and of sensemaking between heterogeneous actants involved in a supposed-to-be public debate.Cet article vise à spécifier comment la quantification d'un phénomène fondée sur une certaine vision du monde se propage et se déforme. Ce projet a été porté par une direction déconcentrée de l'Etat soucieuse de l'emprise croissante du bâti sur les terres agricoles en Languedoc-Roussillon. Le cadre théorique mobilisé, la sociologie de la traduction, permet d'identifier les grandes étapes d'intéressement, d'enrôlement, ainsi que le développement de controverses. Les difficultés rencontrées interrogent sur la complexité de clôture de processus innovants s'agissant de production d'information et de co-construction de sens associant des actants hétérogènes impliqués dans des procédures de débat public
Distribution, functional impact, and origin mechanisms of copy number variation in the barley genome
BACKGROUND There is growing evidence for the prevalence of copy number variation (CNV) and its role in phenotypic variation in many eukaryotic species. Here we use array comparative genomic hybridization to explore the extent of this type of structural variation in domesticated barley cultivars and wild barleys. RESULTS A collection of 14 barley genotypes including eight cultivars and six wild barleys were used for comparative genomic hybridization. CNV affects 14.9% of all the sequences that were assessed. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. CNVs are enriched near the ends of all chromosomes except 4H, which exhibits the lowest frequency of CNVs. CNV affects 9.5% of the coding sequences represented on the array and the genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases. Sequence-based comparisons of CNV between cultivars Barke and Morex provided evidence that DNA repair mechanisms of double-strand breaks via single-stranded annealing and synthesis-dependent strand annealing play an important role in the origin of CNV in barley. CONCLUSIONS We present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley, and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance. We also identify potential mechanisms that can generate variation in copy number in plant genomes.This work was financially supported by the following grants:
project GABI-BARLEX, German Federal Ministry of Education and Research
(BMBF), #0314000 to MP, US, KFXM and NS; Triticeae Coordinated
Agricultural Project, USDA-NIFA #2011-68002-30029 to GJM; and Agriculture
and Food Research Initiative Plant Genome, Genetics and Breeding Program
of USDA’s Cooperative State Research and Extension Service, #2009-65300-
05645 to GJM
Former of Turn Trajectory of Sliding Valve Shaft of Gas Line
Former of turn trajectory of sliding valve shaft of gas line, that allows to provide desired motion trajectory of sliding valve and its full closing, is considered in that paper. Imitation model of that former, research results, which allow to detect influence of gain factor and time constant of position controller on value of speed error, that has impact on delay of output coordinate from setting, and that results to delay of sliding valve motion process to setting position point, are shown
Measuring tiny mass accretion rates onto young brown dwarfs
We present low-resolution Keck I/LRIS spectra spanning from 3200-9000 A of
nine young brown dwarfs and three low-mass stars in the TW Hya Association and
in Upper Sco. The optical spectral types of the brown dwarfs range from
M5.5-M8.75, though two have near-IR spectral types of early L-dwarfs. We report
new accretion rates derived from excess Balmer continuum emission for the
low-mass stars TW Hya and Hen 3-600A and the brown dwarfs 2MASS
J12073347-3932540, UScoCTIO 128, SSSPM J1102-3431, UScoJ160606.29-233513.3,
DENIS-P J160603.9-205644, and Oph J162225-240515B, and upper limits on
accretion for the low-mass star Hen 3-600B and the brown dwarfs UScoCTIO 112,
Oph J162225-240515A, and USco J160723.82-221102.0. For the six brown dwarfs in
our sample that are faintest at short wavelengths, the accretion luminosity or
upper limit is measurable only when the image is binned over large wavelength
intervals. This method extends our sensivity to accretion rate down to ~1e-13
solar masses/year for brown dwarfs. Since the ability to measure an accretion
rate from excess Balmer continuum emission depends on the contrast between
excess continuum emission and the underlying photosphere, for objects with
earlier spectral types the upper limit on accretion rate is much higher.
Absolute uncertainties in our accretion rate measurements of ~3-5 include
uncertainty in accretion models, brown dwarf masses, and distance. The
accretion rate of 2e-12 solar masses/year onto 2MASS J12073347-3932540 is
within 15% of two previous measurements, despite large changes in the H-alpha
flux.Comment: Accepted by ApJ. 23 pages, 5 figures, 3 table
Neural signals predict information sharing across cultures
Information sharing influences which messages spread and shape beliefs, behavior, and culture. In a preregistered neuroimaging study conducted in the United States and the Netherlands, we demonstrate replicability, predictive validity, and generalizability of a brain-based prediction model of information sharing. Replicating findings in Scholz et al., Proc. Natl. Acad. Sci. U.S.A. 114, 2881–2886 (2017), self-, social-, and value-related neural signals in a group of individuals tracked the population sharing of US news articles. Preregistered brain-based prediction models trained on Scholz et al. (2017) data proved generalizable to the new data, explaining more variance in population sharing than self-report ratings alone. Neural signals (versus self-reports) more reliably predicted sharing cross-culturally, suggesting that they capture more universal psychological mechanisms underlying sharing behavior. These findings highlight key neurocognitive foundations of sharing, suggest potential target mechanisms for interventions to increase message effectiveness, and advance brain-as-predictor research
Homeoviscous response of Clostridium pasteurianum to butanol toxicity during glycerol fermentation
Clostridium pasteurianum ATCC 6013 achieves high n-butanol production when glycerol is used as the sole carbon source. In this study, the homeoviscous membrane response of C. pasteurianum ATCC 6013 has been examined through n-butanol challenge experiments. Homeoviscous response is a critical aspect of n-butanol tolerance and has not been examined in detail for C. pasteurianum. Lipid membrane compositions were examined for glycerol fermentations with n-butanol production, and during cell growth in the absence of n-butanol production, using gas chromatography–mass spectrometry (GC–MS) and proton nuclear magnetic resonance (1H-NMR). Membrane stabilization due to homeoviscous response was further examined by surface pressure–area (π–A) analysis of membrane extract monolayers. C. pasteurianum was found to exert a homeoviscous response that was comprised of an increase lipid tail length and a decrease in the percentage of unsaturated fatty acids with increasing n-butanol challenge. This led to a more rigid or stable membrane that counteracted n-butanol fluidization. This is the first report on the changes in the membrane lipid composition during n-butanol production by C. pasteurianum ATCC 6013, which is a versatile microorganism that has the potential to be engineered as an industrial n-butanol producer using crude glycerol
Acoustic radiation controls friction: Evidence from a spring-block experiment
Brittle failures of materials and earthquakes generate acoustic/seismic waves
which lead to radiation damping feedbacks that should be introduced in the
dynamical equations of crack motion. We present direct experimental evidence of
the importance of this feedback on the acoustic noise spectrum of
well-controlled spring-block sliding experiments performed on a variety of
smooth surfaces. The full noise spectrum is quantitatively explained by a
simple noisy harmonic oscillator equation with a radiation damping force
proportional to the derivative of the acceleration, added to a standard viscous
term.Comment: 4 pages including 3 figures. Replaced with version accepted in PR
Deep Near-Infrared Imaging of the rho Oph Cloud Core: Clues to the Origin of the Lowest-Mass Brown Dwarfs
A search for young substellar objects in the rho Oph cloud core region has
been made using the deep-integration Combined Calibration Scan images of the
2MASS extended mission in J, H and Ks bands, and Spitzer IRAC images at 3.6,
4.5, 5.8 and 8.0 microns. The field of view of the combined observations was 1
deg x 9.3 arcmin, and the 5 sigma limiting magnitude at J was 20.5. Comparison
of the observed SEDs with the predictions of the COND and DUSTY models, for an
assumed age of 1 Myr, supports the identification of many of the sources with
brown dwarfs, and enables the estimation of effective temperature, Teff. The
cluster members are then readily distinguishable from background stars by their
locations on a plot of flux density versus Teff. The range of estimated Teff
extends down to ~ 750 K, suggesting the presence of objects of sub-Jupiter
mass. The results also suggest that the mass function for the rho Oph cloud
resembles that of the sigma Orionis cluster based on a recent study, with both
rising towards lower masses. The other main result from our study is the
apparent presence of a progressive blueward skew in the distribution of J-H and
H-Ks colors, such that the blue end of the range becomes increasingly bluer
with increasing magnitude. We suggest that this behavior might be understood in
terms of the 'ejected stellar embryo' hypothesis, whereby some of the
lowest-mass brown dwarfs could escape to locations close to the front edge of
the cloud, and thereby be seen with less extinction.Comment: 37 pages, 10 figures; to be published in Ap
A long-period massive planet around HD106515A
We have performed RV monitoring of the components of the binary system HD
106515 over about 11 years using the high resolution spectrograph SARG at TNG.
The primary shows long-period radial velocity variations that indicate the
presence of a low mass companion whose projected mass is in the planetary
regime (m sin i = 9.33 Mjup). The 9.8 years orbit results quite eccentric
(e=0.57), as typical for massive giant planets. Our results confirm the
preliminary announcement of the planet included in Mayor et al. (2011). The
secondary instead does not show significant RV variations. The two components
do not differ significantly in chemical composition, as found for other pairs
for which one component hosts giant planets. Adaptive optics images obtained
with AdOpt@TNG do not reveal additional stellar companions. From the analysis
of the relative astrometry of the components of the wide pair we put an upper
limit on the mass of the newly detected companion of about 0.25 Msun. State of
art or near future instrumentation can provide true mass determination, thanks
to the availability of the wide companion HD106515B as reference. Therefore,
HD106515Ab will allow deeper insight in the transition region between planets
and brown dwarfs.Comment: A&A, accepted, 8 pages, 10 figure
On-demand semiconductor single-photon source with near-unity indistinguishability
Single photon sources based on semiconductor quantum dots offer distinct
advantages for quantum information, including a scalable solid-state platform,
ultrabrightness, and interconnectivity with matter qubits. A key prerequisite
for their use in optical quantum computing and solid-state networks is a high
level of efficiency and indistinguishability. Pulsed resonance fluorescence
(RF) has been anticipated as the optimum condition for the deterministic
generation of high-quality photons with vanishing effects of dephasing. Here,
we generate pulsed RF single photons on demand from a single,
microcavity-embedded quantum dot under s-shell excitation with 3-ps laser
pulses. The pi-pulse excited RF photons have less than 0.3% background
contributions and a vanishing two-photon emission probability.
Non-postselective Hong-Ou-Mandel interference between two successively emitted
photons is observed with a visibility of 0.97(2), comparable to trapped atoms
and ions. Two single photons are further used to implement a high-fidelity
quantum controlled-NOT gate.Comment: 11 pages, 11 figure
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