Abundances of demersal sharks and chimaera from 1994-2009 scientific surveys in the central Mediterranean sea

Bibliographic and data gathered in scientific bottom trawl surveys carried out off the Southern Coasts of Sicily (Mediterranean Sea), from 1994 to 2009 and between a depth of 10 and 800 m, were analysed in order to prepare a checklist of demersal sharks and chimaera, which are species sensitive to fisheries exploitation. Out of the 27 previously reported demersal shark and chimaera taxa in the Mediterranean, only 23 were found in literature and 20 sampled during the surveys in the investigated area. Among the species sampled in the surveys, only 2 ubiquitous (Squalus blainville and Scyliorhinus canicula) and 3 deep-water (Chimaera monstrosa, Centrophorus granulosus and Galeus melastomus) species showed a wide geographical distribution with a consistent abundance. Excluding the rare (such as Oxynotus centrina) or uncommon shark (e.g. Squalus acanthias), the estimated frequencies of occurrence and abundance indexes show a possible risk of local extinction for the almost exclusively (e.g. angelshark, Squatina spp.) or preferential (e.g. Scyliorhinus stellaris) neritic species.peer-reviewe

Targeted Metabolic Profiling Indicates Apple Rootstock Genotype-Specific Differences in Primary and Secondary Metabolite Production and Validate Quantitative Contribution From Vegetative Growth

Previous reports regarding rhizodeposits from apple roots are limited, and complicated by microbes, which readily colonize root systems and contribute to modify rhizodeposit metabolite composition. This study delineates methods for collection of apple rhizodeposits under axenic conditions, indicates rootstock genotype-specific differences and validates the contributions of vegetative activity to rhizodeposit quantity. Primary and phenolic rhizodeposit metabolites collected from two apple rootstock genotypes, G935 and M26, were delineated 2 months after root initiation by utilizing gas chromatography/liquid chromatography—mass spectrometry (GC/LC-MS), respectively. Twenty-one identified phenolic compounds and 29 sugars, organic acids, and amino acids, as well as compounds tentatively identified as triterpenoids were present in the rhizodeposits. When adjusted for whole plant mass, hexose, erythrose, galactose, phloridzin, kaempferol-3-glucoside, as well as glycerol, and glyceric acid differed between the genotypes. Phloridzin, phloretin, epicatechin, 4-hydroxybenzoic acid, and chlorogenic acid were among the phenolic compounds found in higher relative concentration in rhizodeposits, as assessed by LC-MS. Among primary metabolites assessed by GC-MS, amino acids, organic acids, and sugar alcohols found in relatively higher concentration in the rhizodeposits included L-asparagine, L-cysteine, malic acid, succinic acid, and sorbitol. In addition, putative ursane triterprenoids, identified based on accurate mass comparison to previously reported triterpenoids from apple peel, were present in rhizodeposits in high abundance relative to phenolic compounds assessed via the same extraction/instrumental method. Validation of metabolite production to tree vegetative activity was conducted using a separate set of micropropagated trees (genotype MM106) which were treated with a toxic volatile compound (butyrolactone) to inhibit activity/kill leaves and vegetative growth. This treatment resulted in a reduction of total collected rhizodeposits relative to an untreated control, indicating active vegetative growth contributes to rhizodeposit metabolites. Culture-based assays indicated an absence of bacterial or fungal endophytes in roots of micropropagated G935 and M26 plants. However, the use of fungi-specific primers in qPCR indicated the presence of fungal DNA in 30% of the samples, thus the contribution of endophytes to rhizodeposits cannot be fully eliminated. This study provides fundamental information for continued research and application of rhizosphere ecology driven by apple rootstock genotype specific rhizodeposition

Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot in wheat

The soil-borne pathogen Rhizoctonia solani AG 8 causes major yield losses in wheat (Triticum aestivum. L) production worldwide. Plant tissues of Brassicaceae species contain glucosinolates that are hydrolyzed in the presence of the enzyme myrosinase into products with pesticidal properties. Growth chamber studies were conducted to determine the effect of the Brassicaceae seed meals (SMs) from Brassica juncea, Brassica napus and Sinapis alba on the suppression of the R. solani AG 8 infection of winter wheat. Pasteurized sandy soils were amended with intact and denatured SMs of rape seed and mustard at a rate of 0.5% by soil weight. Regardless of the glucosinolate type and content, all intact and denatured Brassicaceae significantly reduced the infection of winter wheat seedlings by R. solani AG 8 compared to the un-amended control. However, soils amended with S. alba SMs had the lowest severity of Rhizoctonia root rot relative to other amended soils. Phytotoxicity arising from the use of Brassicaceae SMs was observed particularly in soils amended with high glucosinolate-containing SMs. These studies demonstrate that Brassicaceae SMs can be used to manage disease caused by R. solani AG-8. However, future studies will need to focus on strategies for diminishing the crop growth-reducing effects associated with Brassicaceae SM amendment to fully maximize these fungicidal benefits. (C) 2013 Elsevier Ltd. All rights reserved.Keywords: Rhizoctonia solani AG-8, Biopesticide, Brassica juncea, Brassica napus, Sinapis alba, Glucosinolate, Seed mealKeywords: Rhizoctonia solani AG-8, Biopesticide, Brassica juncea, Brassica napus, Sinapis alba, Glucosinolate, Seed mea

Spin-orbit coupled spin-polarised hole gas at the CrSe2-terminated surface of AgCrSe2

Funding: We gratefully acknowledge support from the European Research Council (through the QUESTDO project, 714193), the Engineering and Physical Sciences Research Council (Grant No. EP/T02108X/1), and the Leverhulme Trust (Grant No. RL-2016-006). S.-J.K., E.A.M., A.Z., and I.M. gratefully acknowledge studentship support from the International Max-Planck Research School for Chemistry and Physics of Quantum Materials. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.In half-metallic systems, electronic conduction is mediated by a single spin species, offering enormous potential for spintronic devices. Here, using microscopic-area angle-resolved photoemission, we show that a spin-polarised two-dimensional hole gas is naturally realised in the polar magnetic semiconductor AgCrSe2 by an intrinsic self-doping at its CrSe2-terminated surface. Through comparison with first-principles calculations, we unveil a striking role of spin-orbit coupling for the surface hole gas, unlocked by both bulk and surface inversion symmetry breaking, suggesting routes for stabilising complex magnetic textures in the surface layer of AgCrSe2.Publisher PDFPeer reviewe

Determining the Electronic Confinement of a Subsurface Metallic State

Dopant profiles in semiconductors are important for understanding nanoscale electronics. Highly conductive and extremely confined phosphorus doping profiles in silicon, known as Si:P δ-layers, are of particular interest for quantum computer applications, yet a quantitative measure of their electronic profile has been lacking. Using resonantly enhanced photoemission spectroscopy, we reveal the real-space breadth of the Si:P δ-layer occupied states and gain a rare view into the nature of the confined orbitals. We find that the occupied valley-split states of the δ-layer, the so-called 1Γ and 2Γ, are exceptionally confined with an electronic profile of a mere 0.40 to 0.52 nm at full width at half-maximum, a result that is in excellent agreement with density functional theory calculations. Furthermore, the bulk-like Si 3pz orbital from which the occupied states are derived is sufficiently confined to lose most of its pz-like character, explaining the strikingly large valley splitting observed for the 1Γ and 2Γ states

Weyl-like points from band inversions of spin-polarised surface states in NbGeSb

Funding: Leverhulme Trust (Grant No. PLP-2015-144), The Royal Society, and the Engineering and Physical Sciences Research Council, UK (Grant No. EP/R031924/1); CALIPSOplus project under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020; International Max Planck Research School for Chemistry and Physics of Quantum Materials (IMPRS-CPQM) (I.M.); EPSRC for studentship support through grant nos. EP/K503162/1 and EP/L505079/1, and EP/L015110/1 (O.J.C., J.M.R., and K.U.).Band inversions are key to stabilising a variety of novel electronic states in solids, from topological surface states to the formation of symmetry-protected three-dimensional Dirac and Weyl points and nodal-line semimetals. Here, we create a band inversion not of bulk states, but rather between manifolds of surface states. We realise this by aliovalent substitution of Nb for Zr and Sb for S in the ZrSiS family of nonsymmorphic semimetals. Using angle-resolved photoemission and density-functional theory, we show how two pairs of surface states, known from ZrSiS, are driven to intersect each other near the Fermi level in NbGeSb, and to develop pronounced spin splittings. We demonstrate how mirror symmetry leads to protected crossing points in the resulting spin-orbital entangled surface band structure, thereby stabilising surface state analogues of three-dimensional Weyl points. More generally, our observations suggest new opportunities for engineering topologically and symmetry-protected states via band inversions of surface states.Publisher PDFPeer reviewe

Direct observation of a uniaxial stress-driven Lifshitz transition in Sr2RuO4

Funding: We gratefully acknowledge support from the European Research Council (Grant No. ERC-714193-QUESTDO), the Royal Society, EPSRC for PhD studentship support through grant number EP/L015110/1 (VS).Pressure represents a clean tuning parameter for traversing the complex phase diagrams of interacting electron systems, and as such has proved of key importance in the study of quantum materials. Application of controlled uniaxial pressure has recently been shown to more than double the transition temperature of the unconventional superconductor Sr2RuO4, leading to a pronounced peak in Tc versus strain whose origin is still under active debate. Here we develop a simple and compact method to passively apply large uniaxial pressures in restricted sample environments, and utilise this to study the evolution of the electronic structure of Sr2RuO4 using angle-resolved photoemission. We directly visualise how uniaxial stress drives a Lifshitz transition of the γ-band Fermi surface, pointing to the key role of strain-tuning its associated van Hove singularity to the Fermi level in mediating the peak in Tc. Our measurements provide stringent constraints for theoretical models of the strain-tuned electronic structure evolution of Sr2RuO4. More generally, our experimental approach opens the door to future studies of strain-tuned phase transitions not only using photoemission but also other experimental techniques where large pressure cells or piezoelectric-based devices may be difficult to implement.Publisher PDFPeer reviewe

KATRIN: status and prospects for the neutrino mass and beyond

The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a high-precision integral spectrum of the endpoint region of T$_{2}$ β decay, with the primary goal of probing the absolute mass scale of the neutrino. After a first tritium commissioning campaign in 2018, the experiment has been regularly running since 2019, and in its first two measurement campaigns has already achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN\u27s design sensitivity is 0.2 eV at the 90% confidence level. In this white paper we describe the current status of KATRIN; explore prospects for measuring the neutrino mass and other physics observables, including sterile neutrinos and other beyond-Standard-Model hypotheses; and discuss research-and-development projects that may further improve the KATRIN sensitivity

Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants