Triple-q octupolar ordering in NpO_2

We report the results of resonant X-ray scattering experiments performed at the Np M_4,5 edges in NpO_2. Below T_0 = 25 K, the development of long-range order of Np electric quadrupoles is revealed by the growth of superlattice Bragg peaks. The electronic transition is not accompanied by any measurable crystallographic distortion, either internal or external, so the symmetry of the system remains cubic. The polarization and azimuthal dependence of the intensity of the resonant peaks is well reproduced assuming Templeton scattering from a triple-q longitudinal antiferroquadrupolar structure. Electric quadrupole order in NpO_2 could be driven by the ordering at T_0 of magnetic octupoles of Gamma_5 symmetry, splitting the Np ground state quartet and leading to a singlet ground state with zero dipole magnetic moment.Comment: 4 Pages, 3 Figures, submitted to Phys. Rev. Lett. v2: resubmitted after referee report

Magnetic Susceptibility of Multiorbital Systems

Effects of orbital degeneracy on magnetic susceptibility in paramagnetic phases are investigated within a mean-field theory. Under certain crystalline electric fields, the magnetic moment consists of two independent moments, e.g., spin and orbital moments. In such a case, the magnetic susceptibility is given by the sum of two different Curie-Weiss relations, leading to deviation from the Curie-Weiss law. Such behavior may be observed in d- and f-electron systems with t_{2g} and Gamma_8 ground states, respectively. As a potential application of our theory, we attempt to explain the difference in the temperature dependence of magnetic susceptibilities of UO_2 and NpO_2.Comment: 4 pages, 3 figure

Lattice Distortion and Octupole Ordering Model in CexLa1-xB6

Possible order parameters of the phase IV in CexLa1-xB6 are discussed with special attention to the lattice distortion recently observed. A \Gamma_{5u}-type octupole order with finite wave number is proposed as the origin of the distortion along the [111] direction. The \Gamma_8 crystalline electric field (CEF) level splits into three levels by a mean field with the \Gamma_{5u} symmetry. The ground and highest singlets have the same quadrupole moment, while the intermediate doublet has an opposite sign. It is shown that any collinear order of \Gamma_{5u}-type octupole moment accompanies the \Gamma_{5g}-type ferro-quadrupole order, and the coupling of the quadrupole moment with the lattice induces the distortion. The cusp in the magnetization at the phase transition is reproduced, but the internal magnetic field due to the octupole moment is smaller than the observed one by an order of magnitude.Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jp

Satellite holmium M-edge spectra from the magnetic phase via resonant x-ray scattering

Developing an expression of resonant x-ray scattering (RXS) amplitude which is convenient for investigating the contributions from the higher rank tensor on the basis of a localized electron picture, we analyze the RXS spectra from the magnetic phases of Ho near the $M_{4,5}$ absorption edges. At the $M_5$ edge in the uniform helical phase, the calculated spectra of the absorption coefficient, the RXS intensities at the first and second satellite spots capture the properties the experimental data possess, such as the spectral shapes and the peak positions. This demonstrates the plausibility of the adoption of the localized picture in this material and the effectiveness of the spectral shape analysis. The latter point is markedly valuable since the azimuthal angle dependence, which is one of the most useful informations RXS can provides, is lacking in the experimental conditions. Then, by focusing on the temperature dependence of the spectral shape at the second satellite spot, we expect that the spectrum is the contribution of the pure rank two profile in the uniform helical and the conical phases while that is dominated by the rank one profile in the intermediate temperature phase, so-called spin slip phase. The change of the spectral shape as a function of temperature indicates a direct evidence of the change of magnetic structures undergoing. Furthermore, we predict that the intensity, which is the same order observed at the second satellite spot, is expected at the fourth satellite spot from the conical phase in the electric dipolar transition.Comment: 24 pages, 5 figure

Assessment of weight gain and control of parasitism by Rhipicephalus microplus in dairy cattle in the field using organosynthetic parasiticide, phytotherapics and homeopathy.

The goal of this research was to compare the effect of the following products on dairy cattle, parasitized by Rhipicephalus microplus: organosynthetics - Clorfenvinfós and Ivermectina (OG); phytotherapics - Eucalyptus oil (EG) and Neem cake (NG); Homeopathy (HG); The control group (CG) received no treatment. Infestation was by R. microplus (MIC) and weight gain (GP) were evaluated. The study included 60 animals (5 groups) from ¾ Dutch / Zebu, aged between 25-44 months and initial weight between 211-477kg. EG and NG showed MIC 84.9% and 14.0% greater than CG, respectively (P <0.05; P = 0). HG and OG had MIC less than CG 24.4% and 16.9%, respectively (P<0.05; P <0.05). EG, NG and OG obtained GP lower than CG in 7.9%, 8.9% and 8.06% (P <0.05) respectively. The HG GP was 4.9% higher (P <0.05) than CG. This was the first research to prove parasitism control by R. microplus in a field test, using homeopathy. The methodology for choosing Homeopathy for the control of enzooties, developed and tested for the first time in this study, proved to be adequate and efficient, opening the possibility for establishing a new methodology for strategic control of parasitism by R. microplus

Tolerance of sugarcane varieties to different levels of water depletion on soil.

Sugarcane is one of the most important crops for Brazilian agribusiness, despite water stress being one of the main limiting factors of growth and productivity. Thus, the objective was to verify if there is variation in the tolerance to water deficit among sugarcane varieties in the soil and climate conditions of Quirinópolis-GO (State of Goiás)

Comparison between modified Gordon & Whitlock and Centrifugal Fluctuation techniques for diagnosis of helminths in cattle.

The present study aimed to verify the degree of correlation between the modified Gordon & Whitlock (GW) and Centrifugal Fluctuation (CF) techniques in the diagnosis of gastrointestinal endoparasites in cattle, and to compile a table with the degree of helminth infection of the Strongyloidea Superfamily, measured by number of eggs per gram of feces (EPG) using the two techniques. Feces samples were collected directly from the rectal bulb of 12 females, ¾ Dutch / zebu, from six months of age, weighing between 100 and 150 kg, naturally parasitized by gastrointestinal nematodes, at Santa Mônica Dairy Station, Embrapa/Gado de Leite, in the Municipality of Valença, Rio de Janeiro, Brazil. Samples were collected every 21 days in a period of 28 months. EPG counts were performed at the Parasitology Laboratory of Embrapa, in the Municipality of Juiz de Fora, MG, Brasil. The CF technique detected 80.81% of positive samples, against 15.17% of the GW technique, demonstrating that the CF technique is more sensitive than the GW for EPG count in cattle. The GW technique showed a higher Coefficient of Variation (CV = 237%) than CF (CV = 68%). However, there was a significant agreement between them (rho = 0.12), confirming the existence of a correlation between them. This confirmation allowed the elaboration of a table of the degree of helminth infection of the Strongyloidea Superfamily based on the two techniques, which will aid in the determination of the treatment threshold. Thus, the absence of parameters in the decision making for the treatment of helminths in cattle, from the degree of infection, considered the great disadvantage of the CF technique, was eliminated

Paramagnetic rare earth oxide Nd2O3 investigated by muon spin spectroscopy

In the context of a systematic study of oxide materials with the muon spin spectroscopy amp; 956;SR technique, we report here on an investigation of paramagnetic Nd2O3. The question was whether the magnetism of Nd3 has an influence on the observed signals. In Nd2O3, as in the other oxides, a weakly paramagnetic component is observed besides the pure diamagnetic fraction. The paramagnetic part is assigned to a transient state formed between the initial atomic and the final bound muonium configuration. In addition, a fast relaxing signal amp; 955; amp; 8764; 7 amp; 956;s amp; 8722;1 with 10 to 20 fraction is seen in longitudinal field. Contrary to this general behavior of the oxide materials, in the present magnetic compound, a resonancelike structure is seen in the temperature range around 40 K.We assign it tentatively to a dynamical process related to the population of the first excited Kramers doublet of the Nd3 ion at 2.6 me

A novel procedure to measure the antioxidant capacity of Yerba maté extracts

Yerba maté extracts have in vitro antioxidant capacity attributed to the presence of polyphenolic compounds, mainly chlorogenic acids and dicaffeoylquinic acid derivatives. DPPH is one of the most used assays to measure the antioxidant capacity of pure compounds and plant extracts. It is difficult to compare the results between studies because this assay is applied in too many different conditions by the different research groups. Thus, in order to assess the antioxidant capacity of yerba maté extracts, the following procedure is proposed: 100 µL of an aqueous dilution of the extracts is mixed in duplicate with 3.0 mL of a DPPH 'work solution in absolute methanol (100 µM.L-1), with an incubation time of 120 minutes in darkness at 37 ± 1 °C, and then absorbance is read at 517 nm against absolute methanol. The results should be expressed as ascorbic acid equivalents or Trolox equivalents in mass percentage (g% dm, dry matter) in order to facilitate comparisons. The AOC of the ethanolic extracts ranged between 12.8 and 23.1 g TE % dm and from 9.1 to 16.4 g AAE % dm. The AOC determined by the DPPH assay proposed in the present study can be related to the total polyphenolic content determined by the Folin-Ciocalteu assay