Critical Field of MGB2 : Crossover from Clean to Dirty Regimes

We have studied the upper critical field, Bc2, in poly-crystalline MgB2 samples in which disorder was varied in a controlled way to carry selectively p and s bands from clean to dirty limit. We have found that the clean regime survives when p bands are dirty and s bands are midway between clean and dirty. In this framework we can explain the anomalous behaviour of Al doped samples, in which Bc2 decreases as doping increases.Comment: 11 pages, 2 figure

The cytotoxic activity of diiron bis-cyclopentadienyl complexes with bridging c3-ligands

Diiron bis-cyclopentadienyl bis-carbonyl cationic complexes with a bridging vinylim-inium ligand, [Fe2Cp2 (CO)(µ-CO){µ-η1:η3-C3 (R′)C2HC1NMe(R′′)}]CF3SO3 (R = Xyl = 2,6-C6H3Me2, R′ = Ph, R′′ = H, 2a; R = Xyl, R′ = R′′ = Me, 2b; R = R′ = Me, R′′ = H, 2c; R = Me, R′ = 2-naphthyl, R′′ = H, 2d; R = Me, R′ = R′′ = Ph, 2e), are easily available from commercial chemicals, robust in aqueous media and exert a variable in vitro cytotoxicity against cancer cell lines depending on the nature of the substituents on the vinyliminium ligand. The anticancer activity is, at least in part, associated to fragmentation reactions, leading to iron oxidation and active neutral and well-defined monoiron species. We report an innovative synthetic procedure for the preparation of 2a,c,d, and a facile method to access the monoiron derivative of 2a, i.e., [FeCp(CO){C1 (NMeXyl)C2HC3 (Ph)C(O)}] (3a). According to IC50 analyses at different times of incubation of the complexes, 3a is significantly faster in inhibiting cell viability compared to its diiron precursor 2a. The neutral complexes [Fe2Cp2 (CO)(µ-CO){µ-k1N:k1C:k1C-C3 (R′)C2 (Se)C1 (NMe2)C4 (CO2Y)C5 (CO2Y)}] (R′ = Y = Me, 4a; R′ = Pr, Y =tBu, 4b; R′ = Y = Et, 4c) are obtained via the two-step modification of the vinyliminium moiety and comprise a bridging selenophene-decorated alkylidene ligand. The antiproliferative activity exhibited by 4a-c is moderate but comparable on the ovarian cancer cell line A2780 and the corresponding cisplatin resistant cell line, A2780cisR. Complexes 4a-c in aqueous solutions undergo progressive release of the alkylidene ligand as a functionalized selenophene, this process being slower in cell culture medium. Since the released selenophenes SeC1 {C(O)R′ }C2 (NMe2)C3 (CO2Y)C4 (CO2Y) (R′ = Y = Me, 5a; R′ = Pr, Y =tBu, 5b) are substantially not cytotoxic, it is presumable that the activity of 4a-c is largely ascribable to the {Fe2Cp2 (CO)2 } scaffold

Genomic predictions for economically important traits in Brazilian Braford and Hereford beef cattle using true and imputed genotypes.

Genomic selection (GS) has played an important role in cattle breeding programs. However, genotyping prices are still a challenge for implementation of GS in beef cattle and there is still a lack of information about the use of low-density Single Nucleotide Polymorphisms (SNP) chip panels for genomic predictions in breeds such as Brazilian Braford and Hereford. Therefore, this study investigated the effect of using imputed genotypes in the accuracy of genomic predictions for twenty economically important traits in Brazilian Braford and Hereford beef cattle. Various scenarios composed by different percentages of animals with imputed genotypes and different sizes of the training population were compared.Article 2

Accuracy of genome-wide imputation in Braford and Hereford beef cattle.

Article 157

Neutron Irradiation of Mg11B2 : From the Enhancement to the Suppression of Superconducting Properties

In this letter we present the effect of neutron irradiation up to fluences of 3.9 1019 n/cm2 on the superconducting properties of MgB2. In order to obtain a disorder structure homogeneously distributed, the experiment was carried out on bulk samples prepared with the 11B isotope. Up to fluences of 1018 n/cm2 the critical temperature is slightly diminished (36 K) and the superconducting properties are significantly improved; the upper critical field is increased from 13.5 T to 20.3 T at 12 K and the irreversibility field is doubled at 5 K. For larger neutron fluences the critical temperature is suppressed down to 12 K and the superconducting properties come out strongly degraded.Comment: 13 pages, 4 figures. Submitted to Appl.Phys.Let

Parameters of scalar resonances from the combined analysis of data on processes ππ→ππ,KKˉ,ηη\pi\pi\to\pi\pi,K\bar{K},\eta\eta and J/ψJ/\psi decays

A combined analysis of data on isoscalar S-wave processes $\pi\pi\to\pi\pi,K\overline{K},\eta\eta$ and on decays $J/\psi\to\phi\pi\pi,\phi K\overline{K}$ from the DM2, Mark III and BESIII collaborations is performed to study $f_0$ mesons. The method of analysis is based on analyticity and unitarity and uses an uniformization procedure. In the analysis limited only to the multi-channel $\pi\pi$-scattering data, two possible sets of parameters of the $f_0(500)$ were found: in both cases the mass was about 700 MeV but the total width was either about 600 or 930 MeV. The extension of the analysis using only the DM2 and Mark III data on the $J/\psi$ decays does not allow to choose between these sets. However, the data from BESIII on the di-pion mass distribution in the decay $J/\psi\to\phi\pi^+\pi^-$ clearly prefers the wider $f_0(500)$ state. Spectroscopic implications from results of the analysis are also discussed.Comment: the formalism is also described (text overlap) in arXiv:1108.3725; new extended analysis of data; revised PRD versio

A beam monitor detector based on doped silica and optical fibres

A beam monitor detector prototype based on doped silica fibres coupled to optical fibres has been designed, constructed and tested, mainly for accelerators used in medical applications. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam has been measured, giving information on beam position, shape and intensity. Mostly based on commercial components, the detector is easy to install, to operate and no electronic components are located near the beam. Tests have been performed with a 2 MeV proton pulsed beam at an average current of 0.8 {\mu}A. The response characteristics of Sb doped silica fibres have been studied for the first time