Direct observation of nanoscale interface phase in the superconducting chalcogenide Kx_{x}Fe2−y_{2-y}Se2_2 with intrinsic phase separation

We have used scanning micro x-ray diffraction to characterize different phases in superconducting K$_{x}$Fe$_{2-y}$Se$_2$ as a function of temperature, unveiling the thermal evolution across the superconducting transition temperature (T$_c\sim$32 K), phase separation temperature (T$_{ps}\sim$520 K) and iron-vacancy order temperature (T$_{vo}\sim$580 K). In addition to the iron-vacancy ordered tetragonal magnetic phase and orthorhombic metallic minority filamentary phase, we have found a clear evidence of the interface phase with tetragonal symmetry. The metallic phase is surrounded by this interface phase below $\sim$300 K, and is embedded in the insulating texture. The spatial distribution of coexisting phases as a function of temperature provides a clear evidence of the formation of protected metallic percolative paths in the majority texture with large magnetic moment, required for the electronic coherence for the superconductivity. Furthermore, a clear reorganization of iron-vacancy order around the T$_{ps}$ and T$_c$ is found with the interface phase being mostly associated with a different iron-vacancy configuration, that may be important for protecting the percolative superconductivity in K$_{x}$Fe$_{2-y}$Se$_2$.Comment: 6 pages, 4 figure

On the helium content of Galactic globular clusters via the R parameter

We estimate the empirical R parameter in 26 Galactic Globular Clusters covering a wide metallicity range, imaged by WFPC2 on board the HST. The improved spatial resolution permits a large fraction of the evolved stars to be measured and permits accurate assessment of radial populaton gradients and completeness corrections. In order to evaluate both the He abundance and the He to metal enrichment ratio, we construct a large set of evolutionary models by adopting similar metallicities and different He contents. We find an absolute He abundance which is lower than that estimated from spectroscopic measurements in HII regions and from primordial nucleosynthesis models. This discrepancy could be removed by adopting a C12O16 nuclear cross section about a factor of two smaller than the canonical value, although also different assumptions for mixing processes can introduce systematical effects. The trend in the R parameter toward solar metallicity is consistent with an upper limit to the He to metal enrichment ratio of the order of 2.5.Comment: accepted for pubblication on Ap

Chemical functionalization of N-doped carbon nanotubes: A powerful approach to cast light on the electrochemical role of specific N-functionalities in the oxygen reduction reaction

© 2016 The Royal Society of Chemistry.In this paper, we describe the combination of two different synthetic approaches to carbon nanotube N-decoration/doping: the chemical functionalization with tailored N-pyridinic groups and the classical Chemical Vapor Deposition (CVD) technique. Accordingly, CVD-prepared N-doped CNMs (NMWs) and their N-decorated (chemically functionalized) counterparts (NMW@N1,2) have been prepared and used as metal-free electrocatalysts for the oxygen reduction reaction (ORR). It has been demonstrated that chemical functionalization occurs on the NMW surface sites responsible for their inherent electrochemical properties and "switches them off". As a result, the ORR promoted by NMW@N1,2 is fully controlled by the appended N-heterocycles. A comparative analysis of N-functionalized samples and N-doped (CVD prepared) materials is used to foster the hypothesis of a unique N-configuration (N-pyridinic) responsible for the overall electrochemical performance in NMWs. In addition to that, original electrochemical insights unveiled during the study are discussed and the truly metal-free action of NMW in ORR catalysis is demonstrated

Safety and efficacy of aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs. The additive, that contains at least 66% of aluminosilicate of sodium, potassium, calcium and magnesium as main component, is intended for use as a technological additive (functional groups: (i) anticaking agents) in premixtures and feedingstuffs for pigs at a maximum inclusion level of 30,000 mg/kg. In the absence of data, the FEEDAP Panel could not conclude on the safety of the additive for the target species and the users. The additive is considered safe for the consumer and the environment at the proposed conditions of use. The additive has the potential to act as an anticaking agent in complete feed of pigs at a concentration of 30,000 mg/kg feed

INFN What Next: Ultra-relativistic Heavy-Ion Collisions

This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.Comment: 99 pages, 56 figure

A Halomethane thermochemical network from iPEPICO experiments and quantum chemical calculations

Internal energy selected halomethane cations CH3Cl+, CH2Cl2+, CHCl3+, CH3F+, CH2F2+, CHClF2+ and CBrClF2+ were prepared by vacuum ultraviolet photoionization, and their lowest energy dissociation channel studied using imaging photoelectron photoion coincidence spectroscopy (iPEPICO). This channel involves hydrogen atom loss for CH3F+, CH2F2+ and CH3Cl+, chlorine atom loss for CH2Cl2+, CHCl3+ and CHClF2+, and bromine atom loss for CBrClF2+. Accurate 0 K appearance energies, in conjunction with ab initio isodesmic and halogen exchange reaction energies, establish a thermochemical network, which is optimized to update and confirm the enthalpies of formation of the sample molecules and their dissociative photoionization products. The ground electronic states of CHCl3+, CHClF2+ and CBrClF2+ do not confirm to the deep well assumption, and the experimental breakdown curve deviates from the deep well model at low energies. Breakdown curve analysis of such shallow well systems supplies a satisfactorily succinct route to the adiabatic ionization energy of the parent molecule, particularly if the threshold photoelectron spectrum is not resolved and a purely computational route is unfeasible. The ionization energies have been found to be 11.47 ± 0.01 eV, 12.30 ± 0.02 eV and 11.23 ± 0.03 eV for CHCl3, CHClF2 and CBrClF2, respectively. The updated 0 K enthalpies of formation, ∆fHo0K(g) for the ions CH2F+, CHF2+, CHCl2+, CCl3+, CCl2F+ and CClF2+ have been derived to be 844.4 ± 2.1, 601.6 ± 2.7, 890.3 ± 2.2, 849.8 ± 3.2, 701.2 ± 3.3 and 552.2 ± 3.4 kJ mol–1, respectively. The ∆fHo0K(g) values for the neutrals CCl4, CBrClF2, CClF3, CCl2F2 and CCl3F and have been determined to be –94.0 ± 3.2, –446.6 ± 2.7, –702.1 ± 3.5, –487.8 ± 3.4 and –285.2 ± 3.2 kJ mol–1, respectively

Assessment of the application for renewal of authorisation of Bactocell ® (Pediococcus acidilactici CNCM I-4622) as a feed additive for all fish and shrimps and its extension of use for all crustaceans

Bactocell \uae is the trade name for a feed additive based on viable cells of a strain of Pediococcus acidilactici. Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on Bactocell \uae  in the context of the renewal of the authorisation for shrimps, salmonids and fish other than salmonids. In addition, the applicant requested the extension of use for all crustaceans. The applicant has provided evidence that the additive currently in the market complies with the existing conditions of authorisation. The FEEDAP Panel concludes that Bactocell \uae Aqua 10 Md/100 Md is safe under the current conditions of authorisation for the target species (all fish, shrimps and all crustaceans), consumers of products from animals fed the additive and the environment. Bactocell \uae Aqua 10 Md/100 Md is non-irritant to skin and eyes and is not a dermal sensitiser, but should be considered a potential respiratory sensitiser. Exposure of users by inhalation is very likely. There is no need for assessing the efficacy of Bactocell \uae in the context of the renewal of the authorisation. The Panel concludes that the additive at the minimum inclusion level of 1  7 10 9  CFU/kg feed has the potential to be efficacious in salmonids and in the new species proposed, i.e. all crustaceans

Efficacy of Bacillus subtilis DSM 28343 as a zootechnical additive (gut flora stabiliser) for calves for rearing

Bacillus subtilis DSM 28343 is a preparation of viable spores of a single strain of B. subtilis intended to be used as a zootechnical additive (functional group: gut flora stabilizer) in feed for calves for rearing to increase growth. In 2018, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) delivered a scientific opinion on the safety and efficacy of Bacillus subtilis DSM 28343 as a feed additive for calves for rearing. This species is considered by EFSA to be suitable for the qualified presumption of safety (QPS) approach to safety assessment. In that opinion, the FEEDAP Panel was unable to conclude on the efficacy of the additive, under the condition of use as proposed by the applicant, due to insufficient data provided. In the current opinion, additional data to demonstrate the efficacy of Bacillus subtilis DSM 28343 were assessed. Based on one study of this application and two studies submitted in the previous application, the Panel concluded that Bacillus subtilis DSM 28343 has the potential to be efficacious as gut flora stabiliser used in feed for calves for rearing at the proposed use level

Safety and efficacy of Natuphos® E (6-phytase) as a feed additive for laying hens, minor poultry and other avian species for laying

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Natuphos\uae E (6-phytase) as a feed additive for laying hens, minor poultry and other avian species for laying. The additive Natuphos\uae E consists of 6-phytase (phytase; Enzyme Commission Number 3.1.3.26) and is intended to be used as a feed additive for laying hens, minor poultry and other avian species for laying as a zootechnical additive, functional group of digestibility enhancers. This additive was previously assessed by the FEEDAP Panel in 2017 for avian and porcine species. The production strain of the phytase present in the product is a genetically modified strain of Aspergillus niger. Based on the previous opinion, the FEEDAP Panel concluded that the genetic modification of the production strain does not give rise to safety concerns. The production strain and its DNA were not detected in the concentrate used to formulate the products. The FEEDAP Panel previously concluded that the additive was safe for the target species, consumers and the environment when used at 200 FTU/kg feed. The additive Natuphos\uae E is not considered to be toxic by inhalation or irritant for skin or eye; however, it should be regarded as a dermal sensitiser and a potential respiratory sensitiser. The additive has the potential to be efficacious in improving the performance and/or the phosphorus utilisation in laying hens at 200 FTU/kg feed; the conclusions drawn in laying hens can be extrapolated to all minor poultry and other avian species for laying