Strategies to valorise agrobiodiversity

The current food value chain is characterised by a highly standardised offer produced in an increasingly monotonous agricultural system. In parallel, there is a growing interest among consumers for traditional or regional crop varieties. The conservation of these crops is often done by civil society organisations like Arche Noah, Pro Specie Rara, Rete Semi Rurali, Réseau Semence Paysanne or Red Andaluza de Semillas. Some networks sell their food products in local niche markets, specialised stores and supermarkets. To increase their visibility, some producer groups in the networks are interested in developing or improving a label to valorise agrobiodiversity to the consumer. Based on a representative consumer survey in four European countries, we show that consumer awareness with respect to traditional, old varieties is low but the interest in "Diversifood", defined as more diverse, locally adapted, healthy and tasty produce, is substantial. Therefore, we state, that the availability of a label to valorise agrobiodiversity would respond to consumer needs and increase the visibility of the work done by the networks – but only if it is embedded in an appropriate communication strategy aimed at raising consumer awareness about agrobiodiversity

Editorial: Woody plants and forest ecosystems in a complex world—Ecological interactions and physiological functioning above and below ground

International audienc

In the Shadow of the Accretion Disk: Higher Resolution Imaging of the Central Parsec in NGC 4261

The physical conditions in the inner parsec of accretion disks believed to orbit the central black holes in active galactic nuclei can be probed by imaging the absorption (by ionized gas in the disk) of background emission from a radio counterjet. We report high angular resolution VLBI observations of the nearby (about 40 Mpc) radio galaxy NGC 4261 that confirm free-free absorption of radio emission from a counterjet by a geometrically thin, nearly edge-on disk at 1.6, 4.8, and 8.4 GHz. The angular width and depth of the absorption appears to increase with decreasing frequency, as expected. We derive an average electron density of ~10E4 per cc at a disk radius of about 0.2 pc, assuming that the inner disk inclination and opening angles are the same as at larger radii. Pressure balance between the thermal gas and the magnetic field in the disk implies an average field strength of 0.1 milligauss at a radius of 0.2 pc. These are the closest-in free-free absorption measurements to date of the conditions in an extragalactic accretion disk orbiting a black hole with a well-determined mass. If a standard advection-dominated accretion flow exists in the disk center, then the transition between thin and thick disk regions must occur at a radius less than 0.2 pc (4000 Schwarzschild radii).Comment: 20 pages including 12 figures. Accepted for publication in Ap

Spin relaxation of localized electrons in n-type semiconductors

The mechanisms that determine spin relaxation times of localized electrons in impurity bands of n-type semiconductors are considered theoretically and compared with available experimental data. The relaxation time of the non-equilibrium angular momentum is shown to be limited either by hyperfine interaction, or by spin-orbit interaction in course of exchange-induced spin diffusion. The energy relaxation time in the spin system is governed by phonon-assisted hops within pairs of donors with an optimal distance of about 4 Bohr radii. The spin correlation time of the donor-bound electron is determined either by exchange interaction with other localized electrons, or by spin-flip scattering of free conduction-band electrons. A possibility of optical cooling of the spin system of localized electrons is discussed.Comment: Submitted to the special issue "Optical Orientation", Semiconductor Science and Technolog

Intensity and frequency noise reduction of a Nd:YAG NPRO via pump light stabilisation

We have shown that pump light intensity stabilisation of a single-mode laser diode pumped Nd:YAG non-planar ring oscillator (NPRO) results in significant intensity noise reduction of the NPRO, as well as frequency noise suppression in the same order of magnitude. This effect does not occur in conventional laser diode array pumped NPROs due to mode beating effects originating in the multi-mode pump. As opposed to individual intensity and frequency stabilisation, pump light stabilisation contributes a simplified stabilisation scheme for single-mode laser diode pumped NPROs for high precision applications

Super-Eddington Atmospheres that Don't Blow Away

We show that magnetized, radiation dominated atmospheres can support steady state patterns of density inhomogeneity that enable them to radiate at far above the Eddington limit, without suffering mass loss. The inhomogeneities consist of periodic shock fronts bounding narrow, high-density regions, interspersed with much broader regions of low density. The radiation flux avoids the regions of high density, which are therefore weighed down by gravity, while gas in the low-density regions is slammed upward into the shock fronts by radiation force. As the wave pattern moves through the atmosphere, each parcel of matter alternately experiences upward and downward forces, which balance on average. Magnetic tension shares the competing forces between regions of different densities, preventing the atmosphere from blowing apart. We calculate the density structure and phase speed of the wave pattern, and relate these to the wavelength, the density contrast, and the factor by which the net radiation flux exceeds the Eddington limit. In principle, this factor can be as large as the ratio of magnetic pressure to mean gas pressure, or the ratio of radiation pressure to gas pressure, whichever is smaller. Although the magnetic pressure must be large compared to the mean gas pressure in order to support a large density contrast, it need not be large compared to the radiation pressure. These highly inhomogeneous flows could represent the nonlinear development of the "photon bubble" instability discovered by Gammie. We briefly discuss the applicability of these solutions to astrophysical systems.Comment: 11 pages, 1 figure, accepted for publication in The Astrophysical Journa

Existence of long-lived isotopes of a superheavy element in natural Au

Evidence for the existence of long-lived isotopes with atomic mass numbers 261 and 265 and abundance of (1-10)x10$^{-10}$ relative to Au has been found in a study of natural Au using an inductively coupled plasma - sector field mass spectrometer. The measured masses fit the predictions made for the masses of $^{261}$Rg and $^{265}$Rg (Z=111) and for some isotopes of nearby elements. The possibility that these isotopes belong to the recently discovered class of long-lived high spin super- and hyperdeformed isomeric states is discussed.Comment: 4 pages, 3 figures, 2 table

Does This Patient Have Acute Mountain Sickness?: The Rational Clinical Examination Systematic Review.

Acute mountain sickness (AMS) affects more than 25% of individuals ascending to 3500 m (11 500 ft) and more than 50% of those above 6000 m (19 700 ft). AMS may progress from nonspecific symptoms to life-threatening high-altitude cerebral edema in less than 1% of patients. It is not clear how to best diagnose AMS. To systematically review studies assessing the accuracy of AMS diagnostic instruments, including the visual analog scale (VAS) score, which quantifies the overall feeling of sickness at altitude (VAS[O]; various thresholds), Acute Mountain Sickness-Cerebral score (AMS-C; ≥0.7 indicates AMS), and the clinical functional score (CFS; ≥2 indicates AMS) compared with the Lake Louise Questionnaire Score (LLQS; score of ≥5). Searches of MEDLINE and EMBASE from inception to May 2017 identified 1245 publications of which 91 were suitable for prevalence analysis (66 944 participants) and 14 compared at least 2 instruments (1858 participants) using a score of 5 or greater on the LLQS as a reference standard. To determine the prevalence of AMS for establishing the pretest probability of AMS, a random-effects meta-regression was performed based on the reported prevalence of AMS as a function of altitude. AMS prevalence, likelihood ratios (LRs), sensitivity, and specificity of screening instruments. The final analysis included 91 articles (comprising 66 944 study participants). Altitude predicted AMS and accounted for 28% of heterogeneity between studies. For each 1000-m (3300-ft) increase in altitude above 2500 m (8200 ft), AMS prevalence increased 13% (95% CI, 9.5%-17%). Testing characteristics were similar for VAS(O), AMS-C, and CFS vs a score of 5 or greater on the LLQS (positive LRs: range, 3.2-8.2; P = .22 for comparisons; specificity range, 67%-92%; negative LRs: range, 0.30-0.36; P = .50 for comparisons; sensitivity range, 67%-82%). The CFS asks a single question: "overall if you had any symptoms, how did they affect your activity (ordinal scale 0-3)?" For CFS, moderate to severe reduction in daily activities had a positive LR of 3.2 (95% CI, 1.4-7.2) and specificity of 67% (95% CI, 37%-97%); no reduction to mild reduction in activities had a negative LR of 0.30 (95% CI, 0.22-0.39) and sensitivity of 82% (95% CI, 77%-87%). The prevalence of acute mountain sickness increases with higher altitudes. The visual analog scale for the overall feeling of sickness at altitude, Acute Mountain Sickness-Cerebral, and clinical functional score perform similarly to the Lake Louise Questionnaire Score using a score of 5 or greater as a reference standard. In clinical and travel settings, the clinical functional score is the simplest instrument to use. Clinicians evaluating high-altitude travelers who report moderate to severe limitations in activities of daily living (clinical functional score ≥2) should use the Lake Louise Questionnaire Score to assess the severity of acute mountain sickness

A Magnetically-Switched, Rotating Black Hole Model For the Production of Extragalactic Radio Jets and the Fanaroff and Riley Class Division

A model is presented in which both Fanaroff and Riley class I and II extragalactic jets are produced by magnetized accretion disk coronae in the ergospheres of rotating black holes. While the jets are produced in the accretion disk itself, the output power still is an increasing function of the black hole angular momentum. For high enough spin, the black hole triggers the magnetic switch, producing highly-relativistic, kinetic-energy-dominated jets instead of Poynting-flux-dominated ones for lower spin. The coronal mass densities needed to trigger the switch at the observed FR break power are quite small ($\sim 10^{-15} g cm^{-3}$), implying that the source of the jet material may be either a pair plasma or very tenuous electron-proton corona, not the main accretion disk itself. The model explains the differences in morphology and Mach number between FR I and II sources and the observed trend for massive galaxies to undergo the FR I/II transition at higher radio power. It also is consistent with the energy content of extended radio lobes and explains why, because of black hole spindown, the space density of FR II sources should evolve more rapidly than that of FR I sources. If the present model is correct, then the ensemble average speed of parsec-scale jets in sources distinguished by their FR I morphology (not luminosity) should be distinctly slower than that for sources with FR II morphology. The model also suggests the existence of a population of high-redshift, sub-mJy FR I and II radio sources associated with spiral or pre-spiral galaxies that flared once when their black holes were formed but were never again re-kindled by mergers.Comment: 14 pages, 2 figures, final version to appear in Sept Ap