pinecone/core-2020-05-10-deduplication huggingface dataset:
New methods to constrain the radio transient rate: results from a survey of four fields with LOFAR

International audienceWe report on the results of a search for radio transients between 115 and 190 MHz with the LOw-Frequency ARray (LOFAR). Four fields have been monitored with cadences between 15 min and several months. A total of 151 images were obtained, giving a total survey area of 2275 deg 2. We analysed our data using standard LOFAR tools and searched for radio transients using the LOFAR Transients Pipeline. No credible radio transient candidate has been detected; however, we are able to set upper limits on the surface density of radio transient sources at low radio frequencies. We also show that low-frequency radio surveys are more sensitive to steep-spectrum coherent transient sources than GHz radio surveys. We used two new statistical methods to determine the upper limits on the transient surface density. One is free of assumptions on the flux distribution of the sources, while the other assumes a power-law distribution in flux and sets more stringent constraints on the transient surface density. Both of these methods provide better constraints than the approach used in previous works. The best value for the upper limit we can set for the transient surface density, using the method assuming a power-law flux distribution, is 1.3 × 10 −3 deg −2 for transients brighter than 0.3 Jy with a timescale of 15 min, at a frequency of 150 MHz. We also calculated for the first time upper limits for the transient surface density for transients of different timescales. We find that the results can differ by orders of magnitude from previously reported, simplified estimates
Feedback control of coherent spin states using weak nondestructive measurements

We consider the decoherence of a pseudo-spin ensemble under collective random rotations, and study, both theoretically and experimentally, how a nondestructive measurement combined with real-time feedback correction can protect the state against such a decoherence process. We theoretically characterize the feedback efficiency with different parameters --- coherence, entropy, fidelity --- and show that a maximum efficiency is reached in the weak measurement regime, when the projection of the state induced by the measurement is negligible. This article presents in detail the experimental results published in [Phys. Rev. Lett. \textbf{110}, 210503 (2013)], where the feedback scheme stabilizes coherent spin states of trapped ultra-cold atoms, and nondestructively probed with a dispersive optical detection. In addition, we study the influence of several parameters, such as atom number and rotation angle, on the performance of the method. We analyze the various decoherence sources limiting the feedback efficiency and propose how to mitigate their effect. The results demonstrate the potential of the method for the real-time coherent control of atom interferometers
Graphical Abstract Biocatalyzed synthesis of difuranosides and their ability to trigger production of TNF-D D Biocatalyzed synthesis of difuranosides and their ability to trigger production of TNF-D D

International audienceTransglycosylation reactions biocatalyzed by the native arabinofuranosidase Araf51 and using D-galactosyl, D-fucosyl and 6-deoxy-6-fluoro-D-galactosyl derivatives as donors and acceptors provided di-to pentahexofuranosides. The immunostimulatory potency of these compounds, and more especially their ability to induce production of TNF-α, was evaluated on the murine macrophage cell line, Raw 264.7. The results obtained showed concentration-dependent and most importantly, structure-dependent responses. Interestingly, oligoarabinofuranosides belonging to the oligopentafuranoside family displayed concentration-, chain length and aglycon-dependent bioactivities irrespective of their fine chemical variations. Thus, neo-oligofuranosides in D-Galf series, as well as their D-Fucf and 6-fluorinated counterparts are indeed potential sources of immunostimulating agents
When Clocks Fail: On Critical Paths and Clock Faults

International audienceWhilst clock fault attacks are known to be a serious security threat, an in-depth explanation of such faults still seems to be put in order. This work provides a theoretical analysis, backed by practical experiments, explaining when and how clock faults occur. Understanding and modeling the chain of events following a transient clock alteration allows to accurately predict faulty circuit behavior. A prediction fully confirmed by injecting variable-duration faults at predetermined clock cycles. We illustrate the process by successfully attacking an fpga aes implementation using a dll-based fpga platform (one-bit fault attack)
Anisotropic superconductivity in NbSe2 probed by magnetic penetration depth

International audienceNbSe2 shows coexistence of a charge density wave (TCDW similar to 32 K) with a superconducting state below T = 7.2 K. Recent ARPES measurements revealed different values of the superconducting gap on the main sheets of the Fermi surface. These results suggest a multigap superconductivity such as in MgB2. The temperature dependence of the magnetic penetration depth (;.(T)) down to T,11 6 has been measured on high quality single crystals in the Meissner state. A strong increase of the in-plane penetration depth is observed, signaling the presence of low lying excitations. Given the relative contributions of each Fermi surface sheet, these measurements indicate that a reduced gap is not necessarily only found on the small Se sheet as suggested by the ARPES measurements. These results are discussed in a framework of multigap superconductivity
Astrophysics The Earth as an extrasolar transiting planet II. HARPS and UVES detection of water vapour, biogenic O 2 , and O 3

International audienceContext. The atmospheric composition of transiting exoplanets can be characterized during transit by spectroscopy. Detections of several chemical species have previously been reported in the atmosphere of gaseous giant exoplanets. For the transit of an Earth twin, models predict that biogenic oxygen (O 2) and ozone (O 3) atmospheric gases should be detectable, as well as water vapour (H 2 O), a molecule linked to habitability as we know it on Earth. Aims. The aim is to measure the Earth radius versus wavelength λ – or the atmosphere thickness h(λ) – at the highest spectral resolution available to fully characterize the signature of Earth seen as a transiting exoplanet. Methods. We present observations of the Moon eclipse of December 21, 2010. Seen from the Moon, the Earth eclipses the Sun and opens access to the Earth atmosphere transmission spectrum. We used two different ESO spectrographs (HARPS and UVES) to take penumbra and umbra high-resolution spectra from ≈3100 to 10 400 Å. A change of the quantity of water vapour above the telescope compromised the quality of the UVES data. We corrected for this effect in the data processing. We analyzed the data by three different methods. The first method is based on the analysis of pairs of penumbra spectra. The second makes use of a single penumbra spectrum, and the third of all penumbra and umbra spectra. Results. Profiles h(λ) are obtained with the three methods for both instruments. The first method gives the best result, in agreement with a model. The second method seems to be more sensitive to the Doppler shift of solar spectral lines with respect to the telluric lines. The third method makes use of umbra spectra, which bias the result by increasing the overall negative slope of h(λ). It can be corrected for this a posteriori from results with the first method. The three methods clearly show the spectral signature of the Rayleigh scattering in the Earth atmosphere and the bands of H 2 O, O 2 , and O 3. Sodium is detected. Assuming no atmospheric perturbations, we show that the E-ELT is theoretically able to detect the O 2 A-band in 8 h of integration for an Earth twin at 10 pc. Conclusions. Biogenic O 2 , O 3 , and water vapour are detected in Earth observed as a transiting planet, and, in principle, would be within reach of the E-ELT for an Earth twin at 10 pc. Key words. Earth – Moon – atmospheric effects – planets and satellites: atmospheres – planets and satellites: terrestrial planets – astrobiolog
Modeling of Water-rock interaction in the Mackenzie Basin: competition between sulfuric and carbonic acids

International audienceThe chemical weathering of continental surfaces depends on many factors including lithology, climate, tectonics, erosion, soil or vegetation, and also on the availability of acidity in the weathering zone. In addition to atmospheric/soil CO2, sulfide oxidation may represent a significant source of protons for weathering reactions as shown previously for the rivers draining the Mackenzie Basin, Canada. Here, a numerical model describing continental weathering reactions based on laboratory kinetic laws is coupled to a dynamic global vegetation model (the B-WITCH model) in order to estimate the impact of sulfide oxidation on chemical weathering and associated atmospheric CO2 consumption fluxes throughout the Mackenzie River basin. The model is first calibrated with available field data for the various sub-basin of the Mackenzie watershed and then, a simulation is performed removing the contribution of sulfuric acid to the weathering system. The main outcomes of the present study are that 1) the dissolved silica export is controlled by secondary minerals reactivity in soils and the calcium and magnesium fluxes are driven by the dissolution of calcite and dolomite, 2) the atmospheric CO2 consumption by weathering processes in the Mackenzie river is limited, accounting for only 24% of the total bicarbonate flux to the ocean, confirming a previous study and suggesting that weathering processes in the Mackenzie watershed acts as a source of carbon to the atmosphere at the geological timescale, and 3) the presence of sulfide minerals within a river basin decreases the apparent net consumption of atmospheric CO2 through chemical weathering. We show that the actual production of sulfuric acid in the weathering zone of the Mackenzie basin reduces the net atmospheric CO2 consumption by about two, compared to what the atmospheric CO2 consumption should be in the absence of sulfide minerals. Sulfuric-acid-driven chemical weathering has thus to be considered at both short and long timescales when looking at the link between chemical weathering and the global carbon cycle
Petrogenesis of late-Variscan high-K alkali-calcic granitoids and calc-alkalic lamprophyres: The Aber-Ildut/North-Ouessant complex, Armorican massif, France

International audienceThe Aber-Ildut/North-Ouessant Variscan granitoid complex in the Armorican Massif is anexample of high-K alkali-calcic zoned pluton, c. 304 Ma in age. A first magmatic batchintruded through a northern EW-trending sinistral transcurrent shear zone, before injectingsouthwards as a huge horizontal zoned sill, with moderately peraluminous muscovite-freegranitoids in the north and strongly peraluminous muscovite-bearing leucogranites to thesouth. The second magmatic stage resulted in the intrusion of a large two-mica leucograniticbody from a root zone along the same shear zone, prior to the end of crystallization of the firstinjection. Finally, ultrapotassic dykes, including calc-alkalic lamprophyres (leucominettes),intrude the complex. The strongly peraluminous granites are interpreted as pure meltingproducts of crustal clay-rich pelitic material. All the other petrographic types, includingleucominettes, are thought to result from mixing of crustal melts and mantle-derived maficliquids. Highly silicic tourmaline-bearing leucogranites are significantly affected by a tetradeffect, in relation with REE complexing behavior. Aber-Ildut/North-Ouessant granitoidsprobably formed during the Variscan late-orogenic stage associated with exhumation andlithospheric thinning, at low pressure and by advective heating of a ≤ 50 km-thick crust fromhot metasomatized asthenosphere
Time-resolved nanosecond imaging of the propagation of a corona-like plasma discharge in water at positive applied voltage polarity

International audienceThe present paper is an experimental study of a pulsed filamentary plasma discharge inside liquid water in pin to plane electrode configuration. Time resolved electrical and imaging diagnostics have been performed. The initiation and the propagation of the discharge have been studied for several experimental parameters. The propagation is continuous and is followed by reilluminations at low water conductivity. The measured propagation velocity of the plasma discharge is 30km/s for the secondary positive mode. This velocity was found to be surprisingly constant whatever the experimental parameters and especially as a function of the water conductivity
Dynamic tracking error with shortfall control using stochastic programming

In this contribution we tackle the issue of portfolio management combining benchmarking and risk control. We propose a dynamic tracking error problem and we consider the problem of monitoring at discrete points the shortfalls of the portfolio below a set of given reference levels of wealth.We formulate and solve the
resulting dynamic optimization problem using stochastic programming. The proposed model allows for a great flexibility in the combination of the tracking goal and the downside risk protection. We provide the results of out-of-sample simulation experiments, on real data, for different portfolio configurations and different market conditions
Effects of 5-HT1B/1D receptor agonist rizatriptan on cerebral blood flow and blood volume in normal circulation.

To investigate the vasoconstrictor effect of 5-hydroxytryptamine (5-HT1B/1D) receptor agonists for migraine treatment, changes in cerebral blood flow (CBF) and blood volume induced by rizatriptan were assessed by positron emission tomography (PET). Eleven healthy volunteers underwent PET studies before and after rizatriptan administration. Dynamic PET data were acquired after bolus injection of H2(15)O to analyze CBF and arterial-to-capillary blood volume (V0) images using the three-weighted integral method. After a baseline scan, three further acquisitions were performed at 40 to 50, 60 and 70 to 80 mins after drug administration. Global and regional differences in CBF and V0 between conditions were compared using absolute values in the whole brain and cortical regions, as well as statistical parametric mapping (SPM) analysis. The global and regional values for CBF and V0 decreased significantly after rizatriptan administration compared with the baseline condition. However, both values recovered to baseline within 80 mins after treatment. The maximal reduction in global CBF and V0 was approximately 13% of baseline value. The greatest decrease in CBF was observed approximately 60 mins after drug administration, whereas the maximal reduction in V0 was observed approximately 5 mins earlier. Statistical parametric mapping did not highlight any regional differences between conditions. Thus, in brain circulation, rizatriptan caused significant CBF and V0 decreases, which are consistent with the vasoconstrictor effect of triptans on the large cerebral arteries. The gradual recovery in the late phase from the maximal CBF and V0 decrease suggests that rizatriptan does not affect the cerebral autoregulatory response in small arteries induced by CBF reduction
Shot noise in magnetic tunneling structures with two-level quantum dots

We analyze shot noise in a magnetic tunnel junction with a two-level quantum
dot attached to the magnetic electrodes. The considerations are limited to the
case when some transport channels are suppressed at low temperatures. Coupling
of the two dot's levels to the electrodes are assumed to be generally different
and also spin-dependent. To calculate the shot noise we apply the approach
based on the full counting statistics. The approach is used to account for
experimental data obtained in magnetic tunnel junctions with organic barriers.
The experimentally observed Fano factors correspond to the super-Poissonian
statistics, and also depend on relative orientation of the electrodes' magnetic
moments. We have also calculated the corresponding spin shot noise, which is
associated with fluctuations of spin current
Mesoporous hybrid materials by simultaneous pseudomorphic transformation and functionalization of silica microspheres

Non-agglomerated amino-functionalized mesoporous silica microspheres are synthesized by a one-pot synthesis from a parent silica material. Narrow pore size distributions in the range from 3 to 5 nm are obtained with alkyltrimethylammonium structure-directing agents. By following the pseudomorphic transformation pathway, the particle size distribution and spherical morphology of the parent silica are retained during the synthesis. The products contain accessible and uniformly distributed amino groups. The average pore size and the ratio of small uniform mesopores (< 5 nm) to larger mesopores and macropores can be controlled by choosing the appropriate structure-directing agent and by adjusting the concentration of the amino-functionalized alkoxysilane precursor, leading to a variety of meso-macroporous hybrid materials
Referral for Specialist Follow-up and Its Association With Post-discharge Mortality Among Patients With Systolic Heart Failure (from the National Heart Failure Audit for England and Wales)

For patients admitted with worsening heart failure (HF), early follow-up after discharge is recommended. Whether outcomes can be improved when follow-up is done by cardiologists is uncertain. We aimed to determine the association between cardiology follow-up and risk of death for patients with HF discharged from hospital. Using data from the National Heart Failure Audit (England and Wales), we investigated the effect of referral to cardiology follow-up on 30-day and 1-year mortality in 68,772 patients with HF and a reduced left ventricular ejection fraction discharged from 185 hospitals from 2007 to 2013. The primary analyses used instrumental variable analysis complemented by hierarchical logistic and propensity-matched models. At the hospital level, rates of referral to cardiologists varied from 6% to 96%. The median odds ratio (OR) for referral to cardiologist was 2.3 (95% confidence interval [CI] 2.1 to 2.5), suggesting that, on average, the odds of a patient being referred for cardiologist follow-up after discharge differed ∼2.3 times from one randomly selected hospital to another one. Based on the proportion of patients (per region) referred for cardiology follow-up, referral for cardiology follow-up was associated with lower 30-day (OR 0.70; 95% CI 0.55 to 0.89) and 1-year mortality (OR 0.81; 95% CI 0.68 to 0.95) compared with no plans for cardiology follow-up (i.e., standard follow-up done by family doctors). Results from hierarchical logistic models and propensity-matched models were consistent (30-day mortality OR 0.66; 95% CI 0.61 to 0.72 and 0.66; 95% CI 0.58 to 0.76 for hierarchical and propensity matched models, respectively). For patients with HF and a reduced left ventricular ejection fraction admitted to hospital with worsening symptoms, referral to cardiology services for follow-up after discharge is strongly associated with reduced mortality, both early and late
The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring

Antarctic krill (Euphausia superba) play a central role in the food web of the Southern Ocean, forming a link between primary production and large predators. Krill produce large, faecal pellets (FP) which can form a large component of mesopelagic particulate organic carbon (POC) fluxes. However, the patchy distribution of krill swarms, highly variable pellet composition, and variable sinking and attenuation rates means that these episodic, but potentially large, carbon fluxes are difficult to sample or model. We measured particle flux and type using Marine Snow Catchers (MSC) in the marginal ice zone near the South Orkneys, Antarctica. Krill FP were the dominant component of the POC flux in the upper 200 m (typically 60-85%).  FP sinking velocities measured onboard were highly variable (15-507 m d-1) but overall high, with mean equivalent velocities of 172, 267 and 161 m d-1 at our three stations. The high numbers of krill FP sinking through the mesopelagic suggest that krill FP can be transferred efficiently and/or that rates of krill FP production are high. We compared our direct MSC-derived estimates of krill FP POC flux (33-154 mg C m-2 d-1) and attenuation to estimates of krill FP production based on previous measurements of krill density and literature FP egestion rates, and estimated net krill FP attenuation rates in the upper mesopelagic. Calculated attenuation rates are sensitive to krill densities in the overlying water column but suggest that krill FP could be transferred efficiently through the upper mesopelagic, and, in agreement with our MSC attenuation estimates, could make large contributions to bathypelagic POC fluxes. Our study contrasts with some others which suggest rapid FP attenuation, highlighting the need for further work to constrain attenuation rates and assess how important the contribution of Antarctic krill FP could be to the Southern Ocean biological carbon pump
Determination of Dipyrone in pharmaceutical preparations based on the chemiluminescent reaction of the quinolinic hydrazide-H2O2-vanadium (IV) system and flow injection analysis

A rapid, economic and sensitive chemiluminescent method involving flow-injection analysis was developed for the determination of dipyrone in pharmaceutical preparations. The method is based on the chemiluminescent reaction between quinolinic hydrazide and hydrogen peroxide in a strongly alkaline medium, in which vanadium(IV) acts as a catalyst. Principal chemical and physical variables involved in the flow-injection system were optimized using a modified simplex method. The variations in the quantum yield observed when dipyrone was present in the reaction medium were used to determine the concentration of this compound. The proposed method requires no preconcentration steps and reliably quantifies dipyrone over the linear range 1–50 µg/mL. In addition, a sample throughput of 85 samples/h is possible. Copyright © 2011 John Wiley & Sons, Ltd
The Planteome database : an integrated resource for reference ontologies, plant genomics and phenomics

The Planteome project (http://www.planteome.org) provides a suite of reference and species-specific ontologies for plants and annotations to genes and phenotypes. Ontologies serve as common standards for semantic integration of a large and growing corpus of plant genomics, phenomics and genetics data. The reference ontologies include the Plant Ontology, Plant Trait Ontology and the Plant Experimental Conditions Ontology developed by the Planteome project, along with the Gene Ontology, Chemical Entities of Biological Interest, Phenotype and Attribute Ontology, and others. The project also provides access to species-specific Crop Ontologies developed by various plant breeding and research communities from around the world. We provide integrated data on plant traits, phenotypes, and gene function and expression from 95 plant taxa, annotated with reference ontology terms. The Planteome project is developing a plant gene annotation platform; Planteome Noctua, to facilitate community engagement. All the Planteome ontologies are publicly available and are maintained at the Planteome GitHub site (https://github.com/Planteome) for sharing, tracking revisions and new requests. The annotated data are freely accessible from the ontology browser (http://browser.planteome.org/amigo) and our data repositorypublishersversionPeer reviewe