Surface and bulk polaritons in a linear magnetoelectric multiferroic with canted spins: Transverse Electric polarisation

Some magnetoelectric multiferroics have a canted spin structure that can be described by a Dzyaloshinkii-Moriya coupling. We calculate properties and features expected for surface and bulk magnon polaritons in such media with a linear magnetoelectric interaction for the case of transverse electric polarisation. The dielectric polarisation and magnetisation of weak ferromagnetism are constrained to lie in the plane parallel to the surface. We examine a geometry with the polarisation oriented in the film plane and present numerical results for the transverse electric polarisation. Particular attention is given to non-reciprocal surface modes, which exist in frequency between two bulk bands, and show how these modes can be modified by external magnetic field. Results for attenuated total reflection are presented, and discussed in relation to nonreciprocity. Example results are calculated for the canted antiferromagnet BaMnF4.Comment: 14 pages, 6 figure

Population structure and dynamics of the cassava green mite Mononychellus tanajoa (Bondar) and the predator Euseius ho (DeLeon) (Acari: Tetranychidae, Phytoseiidae).

Population structure and dynamics of the cassava green mite Mononychellus tanajoa and the predator Euseius ho (Acari: Tetranychidae, Phytoseiidae). Cassava is attacked by several pests, among which the cassava green mite Mononychellus tanajoa.bitstream/item/123027/1/Population-structure-and-dynamics-Tabuleiros-Costeiros.pd

Degradabilidade da matéria seca e parâmetros cinéticos da disgestão de cultivares de alfafa avaliados pelo método de produção de gás.

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After-effects of thixotropic conditionings on operational chest wall and compartmental volumes of patients with Parkinson’s disease

Individuals with Parkinson’s disease (PD) present respiratory dysfunctions, mainly due to decreased chest wall expansion, which worsens with the course of the disease. These findings contribute to the restrictive respiratory pattern and the reduction in chest wall volume. According to literature, inspiratory muscle thixotropic conditioning maneuvers may improve lung volumes in these patients. The study aimed to determine the after-effects of respiratory muscle thixotropic maneuvers on breathing patterns and chest wall volumes of PD. A crossover study was performed with twelve patients with PD (8 males; mean age 63.9±8.8 years, FVC%pred 89.7±13.9, FEV1%pred 91.2±15, FEV1/FVC%pred 83.7±5.7). Chest wall volumes were assessed using OEP during thixotropic maneuvers. Increases in EIVCW (mean of 126mL, p = 0.01) and EEVCW (mean of 150mL, p = 0.005) were observed after DITLC (deep inspiration from total lung capacity) due to increases in pulmonary (RCp) and abdominal (RCa) ribcage compartments. Changes in ICoTLC (inspiratory contraction from TLC) led to significant EIVCW (mean of 224mL, p = 0.001) and EEVCW (mean of 229mL, p = 0.02) increases that were mainly observed in the RCp. No significant changes were found when performing DERV (deep expiration from residual volume) and ICoRV (Inspiratory contraction from RV). Positive correlations were also observed between the degree of inspiratory contraction during ICoTLC and EEVRCp (rho = 0.613, p = 0.03) and EIVRCp (rho = 0.697, p = 0.01) changes. Thixotropy conditioning of inspiratory muscles at an inflated chest wall volume increases EIVCW and EEVCW in the ten subsequent breaths in PD patients. These maneuvers are easy to perform, free of equipment, low-cost, and may help patients improve chest wall volumes during rehabilitation

THE USE OF N400 IN STUDIES OF STIMULUS EQUIVALENCE: A REVIEW OF METHODS AND PARAMETERS

The N400 is defined as an event-related brain potential that is sensitive to the semantic relations between stimuli. For instance, when a pair of words belong to the same semantic domain (e.g., monkey-banana), the N400 will be significantly reduced in comparison to the N400 evoked by unrelated words (e.g., monkey-carburetor). Notably, the N400 responses are also sensitive to the arbitrary stimulus-stimulus relations formed by matching-to-sample procedures (MTS), supporting the notion that stimulus equivalence is a behavioristic model of semantic relations. In this study, we presented a methodological review of studies on stimulus equivalence that used the N400 as dependent measure of “equivalent” and “non-equivalent” stimulus-stimulus relations formed by MTS procedures. First, we searched on databases for studies that used the descriptive terms “equivalence relations”, “matching-to-sample”, “MTS”, “N400”, “relational learning”, and “derived relations” on the title and the abstract. Then, we categorized the number of experiments in each study, population, nature of stimuli, the event-related brain potential used as a dependent measure and whether the critical probes comprised baseline, reflexive, symmetric or transitive relations. We found that the MTS variables differed substantially from one study to another. Considering that most of these MTS variables may be critical to the establishment of stimulus equivalence, we encourage follow-up studies that aim at verifying whether and to what extent they can be related to the N400 outcomes.Key-words: Matching-to-sample, equivalence-relatedness-based-procedure, stimulus equivalence, N400, semantic relations, methodological review

Tiller Population Density and Sward Stability of Brachiaria brizantha Continuously Stocked by Cattle

Tiller population density is one the most important parameters of sward structure and its evaluation is normally included in studies of sward dynamics. Moreover, a greater level of understanding is achieved when the survival of successive tiller generations is monitored. (Matthew et al., 2000). This would help to explain seasonal variation in tiller populations based on tiller appearance and death rates. While Brachiaria brizantha c.v. Marandu occupies up to 70 million hectares of cultivated grassland in Brazil, little is known of its ecophysiology. The objective of this work was to calculate survival probability of B. brizantha tillers and identify seasonal variation on sward stability