Magnetic, thermal and transport properties of Cd doped CeIn3_3

We have investigated the effect of Cd substitution on the archetypal heavy fermion antiferromagnet CeIn$_3$ via magnetic susceptibility, specific heat and resistivity measurements. The suppression of the Neel temperature, T$_{N}$, with Cd doping is more pronounced than with Sn. Nevertheless, a doping induced quantum critical point does not appear to be achievable in this system. The magnetic entropy at $T_N$ and the temperature of the maximum in resistivity are also systematically suppressed with Cd, while the effective moment and the Curie-Weiss temperature in the paramagnetic state are not affected. These results suggest that Cd locally disrupts the AFM order on its neighboring Ce moments, without affecting the valence of Ce. Moreover, the temperature dependence of the specific heat below $T_N$ is not consistent with 3D magnons in pure as well as in Cd-doped CeIn$_3$, a point that has been missed in previous investigations of CeIn$_3$ and that has bearing on the type of quantum criticality in this system

Association of a green tea extract with serum immunoglobulin G status and neonatal vitality in newborn dairy calves

Poor vigor at birth has been associated with reduced IgG absorption from colostrum and a reduced vitality in neonatal dairy calves. Some natural compounds, such as green tea extract, may improve vitality in compromised calves. The objective of this randomized controlled trial was to evaluate the potential of supplementing a green tea extract (15 mL) to calves to improve vigor and activity behavior for the first 72 h postnatal. Also, this study aimed to investigate the influence of green tea extract supplementation on calf serum IgG concentration and the apparent efficiency of absorption (AEA) of colostral IgG. Holstein calves (n = 24) weighing 42.49 ± 1.07 kg postnatal received a complete random assignment at 3 h of one 15-mL dose of green tea extract (Calf Perk, TechMix) or distilled water orally before tube feeding colostrum replacer (Premolac Plus IgG, Zinpro) at 4 h postnatal. Two observers assessed for calving time and dystocia by live video stream to retrieve all calves within 2 h postnatal. One veterinarian performed a baseline vigor assessment based on heart rate and response to stimuli on all calves at 2.5 h, before colostrum feeding at 3.75 h, as well as at 24, 48, and 72 h postnatal. Calf blood samples were taken to assess total IgG by radial immunodiffusion assay at 2.5, 6, 12, 24, 48, and 72 h. Calf vitality was also observed continuously by video for all calves to determine whether treatment was associated with attempts to stand, lying time, and exploration of their pen environment for the first 24 h. We used an ordinal logistic model to evaluate the odds of green tea extract improving a calf\u27s vigor category from 2.5 h postnatal to 72 h of age. Vigor score was categorized as abnormal (≤4), average (5), or alert (≥6), with hour as a fixed effect. We also ran mixed linear models to evaluate the effect of extract on total IgG and AEA, with time and dystocia as fixed effects. Five dystocia calves were enrolled (2 control, 3 extract), but assistance was minor (e.g., manual assistance and all were assisted within 1 h). Baseline vigor scores and baseline total IgG were not different between groups. Vigor score category was not associated with green tea extract supplementation (odds ratio 1.17; 95% CI: 0.43–3.15) but increased with time compared with controls. We observed no association of treatment with total IgG or AEA in the calves, suggesting green tea extract does not compromise IgG absorption. Calf vitality, lying behavior, and exploratory behavior were not associated with green tea extract treatment. Our findings suggest that green tea extract supplementation does not affect AEA and serum IgG concentration in calves. Future research should evaluate whether green tea extract improves vitality in calves experiencing severe dystocia

Composição química e digestibilidade in vitro do pedúnculo de caju.

O presente trabalho se propõe a avaliar a composição química-bromatológica e a digestibilidade in vitro do pedúnculo de caju, um subproduto fibroso, tratado ou não tratado com ureia

Training-induced inversion of spontaneous exchange bias field on La1.5Ca0.5CoMnO6

In this work we report the synthesis and structural, electronic and magnetic properties of La1.5Ca0.5CoMnO6 double-perovskite. This is a re-entrant spin cluster material which exhibits a non-negligible negative exchange bias effect when it is cooled in zero magnetic field from an unmagnetized state down to low temperature. X-ray powder diffraction, X-ray photoelectron spectroscopy and magnetometry results indicate mixed valence state at Co site, leading to competing magnetic phases and uncompensated spins at the magnetic interfaces. We compare the results for this Ca-doped material with those reported for the resemblant compound La1.5Sr0.5CoMnO6, and discuss the much smaller spontaneous exchange bias effect observed for the former in terms of its structural and magnetic particularities. For La1.5Ca0.5CoMnO6, when successive magnetization loops are carried, the spontaneous exchange bias field inverts its sign from negative to positive from the first to the second measurement. We discuss this behavior based on the disorder at the magnetic interfaces, related to the presence of a glassy phase. This compound also exhibits a large conventional exchange bias, for which there is no sign inversion of the exchange bias field for consecutive cycles

Probing the localized to itinerant behavior of the 4f electron in CeIn3-xSnx by Gd3+ electron spin resonance

The CeIn3-xSnx cubic heavy fermion system presents an antiferromagnetic transition at T_N = 10 K, for x = 0, that decreases continuously down to 0 K upon Sn substitution at a critical concentration of x_c ~ 0.65. In the vicinity of T_N -> 0 the system shows non-Fermi liquid behavior due to antiferromagnetic critical fluctuations. For a high Sn content, x > 2.2, intermediate valence effects are present. In this work we show that Gd3+-doped electron spin resonance (ESR) probes a change in the character of the Ce 4f electron, as a function of Sn substitution. The Gd3+ ESR results indicate a transition of the Ce 4f spin behavior from localized to itinerant. Near the quantum critical point, on the antiferromagnetic side of the magnetic phase diagram, both localized and itinerant behaviors coexist.Comment: 9 pages, 7 figure

Diferentes teores de proteína metabolizável em rações com cana-de-açúcar para vacas em lactação.

O presente trabalho teve como objetivo avaliar o efeito de diferentes teores de proteína metabolizável (PM) na ração de vacas lactantes alimentadas com cana-de-açúcar

Distinct high-T transitions in underdoped Ba1−x_{1-x}Kx_{x}Fe2_{2}As2_{2}

In contrast to the simultaneous structural and magnetic first order phase transition $T_{0}$ previously reported, our detailed investigation on an underdoped Ba$_{0.84}$K$_{0.16}$Fe$_{2}$As$_{2}$ single crystal unambiguously revealed that the transitions are not concomitant. The tetragonal ($\tau$: I4/mmm) - orthorhombic ($\vartheta$: Fmmm) structural transition occurs at $T_{S}\simeq$ 110 K, followed by an adjacent antiferromagnetic (AFM) transition at $T_{N}\simeq$ 102 K. Hysteresis and coexistence of the $\tau$ and $\vartheta$ phases over a finite temperature range observed in our NMR experiments confirm the first order character of the structural transition and provide evidence that both $T_{S}$ and $T_{N}$ are strongly correlated. Our data also show that superconductivity (SC) develops in the $\vartheta$ phase below $T_{c}$ = 20 K and coexists with long range AFM. This new observation, $T_{S}\neq T_{N}$, firmly establishes another similarity between the hole-doped BaFe$_{2}$As$_{2}$ via K substitution and the electron-doped iron-arsenide superconductors.Comment: 4 pages, 3 figure

Desempenho de bezerras leiteiras alimentadas com concentrado inicial contendo sais de ácidos orgânicos ou monesina.

O objetivo deste trabalho foi avaliar o efeito da inclusão de butirato de sódio, monensina sódica e propionato de cálcio no concentrado inicial sobre o desempenho de bezerras leiteiras antes e após o desaleitamento. Vinte e quatro bezerras Holandesas recém-nascidas foram alocadas em abrigos individuais até a décima semana de vida tendo livre acesso à água, alimentadas com 4L de leite/dia, em duas refeições, sendo bloqueadas em função do peso ao nascer a um dos tratamentos, de acordo com o aditivo no concentrado: 1)Butirato de sódio (0,15%); 2)Monensina sódica (30 ppm); 3)Propionato de cálcio (0,15%). Durante 10 semanas os animais receberam concentrado inicial até 2 kg/d e receberam também feno de capim-coast-cross à vontade após o desaleitamento. Semanalmente, os animais foram pesados e avaliados quanto à altura da cernelha, largura do traseiro e perímetro torácico. Não foram observados efeitos significativos entre os tratamentos para o consumo de concentrado e de feno, peso vivo e ganho de peso diário dos animais (P>0,05), entretanto foram observados efeitos de idade (P0,05). A inclusão dos aditivos resultou em desempenho satisfatório de bezerras leiteiras antes e após o desaleitamento. A monensina sódica pode ser substituída por sais de ácidos orgânicos sem prejuízo ao desempenho de bezerros

Electron spin resonance study of the LaIn3-xSnx superconducting system

The LaIn3-xSnx alloy system is composed of superconducting Pauli paramagnets. For LaIn3 the superconducting critical temperature T_c is approximately 0.7 K and it shows an oscillatory dependence as a function of Sn substitution, presenting its highest value T_c ~ 6.4 K for the LaSn3 end member. The superconducting state of these materials was characterized as being of the conventional type. We report our results for Gd3+ electron spin resonance (ESR) measurements in the LaIn3-xSnx compounds as a function of x. We show that the effective exchange interaction parameter J_fs between the Gd3+ 4f local moment and the s-like conduction electrons is almost unchanged by Sn substitution and observe microscopically that LaSn3 is a conventional superconductor.Comment: 9 pages, 4 figures. Replaced with the published version and updated the bibliographic informatio

Pressure and chemical substitution effects in the local atomic structure of BaFe2As2

The effects of K and Co substitutions and quasi-hydrostatic applied pressure (P<9 GPa) in the local atomic structure of BaFe2As2, Ba(Fe{0.937}Co{0.063})2As2 and Ba{0.85}K{0.15}Fe2As2 superconductors were investigated by extended x-ray absorption fine structure (EXAFS) measurements in the As K absorption edge. The As-Fe bond length is found to be slightly reduced (<~ 0.01 Angstroms) by both Co and K substitutions, without any observable increment in the corresponding Debye Waller factor. Also, this bond is shown to be compressible (k = 3.3(3)x10^{-3} GPa^{-1}). The observed contractions of As-Fe bond under pressure and chemical substitutions are likely related with a reduction of the local Fe magnetic moments, and should be an important tuning parameter in the phase diagrams of the Fe-based superconductors.Comment: 7 pages, 6 figure