Experimental and theoretical evidences for the ice regime in planar artificial spin ices

In this work, we explore a kind of geometrical effect in the thermodynamics of artificial spin ices (ASI). In general, such artificial materials are athermal. Here, We demonstrate that geometrically driven dynamics in ASI can open up the panorama of exploring distinct ground states and thermally magnetic monopole excitations. It is shown that a particular ASI lattice will provide a richer thermodynamics with nanomagnet spins experiencing less restriction to flip precisely in a kind of rhombic lattice. This can be observed by analysis of only three types of rectangular artificial spin ices (RASI). Denoting the horizontal and vertical lattice spacings by a and b, respectively, then, a RASI material can be described by its aspect ratio $\gamma$=a/b. The rhombic lattice emerges when $\gamma$=$\sqrt{3}$. So, by comparing the impact of thermal effects on the spin flips in these three appropriate different RASI arrays, it is possible to find a system very close to the ice regime

Diversidade em acessos de umbuzeiro, com base na morfologia e nas correlações entre caracteres foliares.

Foram realizadas caracterizações morfológicas em 72 acessos (clone) pertencentes ao banco de germoplasma de umbuzeiro da Embrapa Semiárido. Foram utilizadas folhas dos acessos para a avaliação dos seguintes caracteres: comprimento da folha (Cf/cm), largura da folha (Lf/cm), comprimento do pecíolo (Cp/cm), comprimento do folíolo terminal (Cft/cm), largura do foliolo terminal (Lft/cm), comprimento do peciololo terminal (Cpt/cm), razão-r1 (comprimento folíolo + peciololo/largura do folíolo terminal/cm), razão-r2 (comprimento folíolo/largura do folíolo terminal/cm), área foliar (Af/cm 22) e número de folíolos (Nf). Foram realizadas análises de correlações simples e outras análises complementares de estatística descritiva e de componentes principais. Nas análises de correlações, foram observados valores positivos e significativos, para a maioria dos caracteres de folhas com exceção, de Nf, que apresentou correlação não significativa com os demais caracteres. Observaram-se percentuais intermediários de coeficientes de variação, com exceção do obtido para a Af, que foi muito elevado (51,6%), o que pode estar relacionado à presença de alguns acessos que apresentam folhas com padrões morfométricos superiores em relação à maioria. Os dois primeiros componentes principais relacionados a Cf e Lf, explicaram 77% da variabilidade existente entre os acessos e ser podem na discriminação dos acessos em geral

Oportunidades e desafios da bovinocultura de corte no Estado do Piauí.

Retrospectiva; Oportunidades; Manejo atual da pastagem e do rebanho; Potencial das pastagens nativas; Manejo da pastagem nativa de mimoso; Desafios.bitstream/item/35885/1/Doc70.pd

Umbuzeiro como porta-enxerto de outras Spondias em condições de sequeiro: avaliações aos cinco anos.

O objetivo desse trabalho é relatar os resultados parciais de um experimento conduzido com a cajazeira, a cirigueleira, a cajá-mangueira, o umbuguela e o umbu-cajazeiro tendo sempre como porta-enxerto o umbuzeiro em condições de sequeiro, após cinco anos da sua instalação

Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology

In this letter, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by $a$ and $b$ respectively). Arrays with three different ratios $\gamma =a/b = \sqrt{2}$, $\sqrt{3}$ and $\sqrt{4}$ are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough $\gamma$. Our results also insinuate that magnetic monopoles may be almost free in rectangular lattices with a critical ratio $\gamma = \gamma_{c} = \sqrt{3}$, supporting previous theoretical predictions

Competição de clones do umbuzeiro: cinco anos após.

O umbuzeiro (Spondias tuberosa Arr.) é endêmico do semi-árido brasileiro

Impact of corticosteroids on late growth of radiofrequency lesions in infant pigs: histopathological and electroanatomical findings

Aims Corticosteroids attenuate late growth of radiofrequency (RF) lesions in the thigh muscle of infant rats. We sought to assess the impact of these drugs on the late growth of RF lesions in immature swine myocardium and to determine the electroanatomical mapping (EAM) characteristics of these lesions.Methods and results Radiofrequency (60 degrees C; 60 s) lesions were created in the right atrium (n = 2) and ventricle (n = 2) of 14 piglets (age 65 days; weight 5 kg) and 3 adults. Piglets were divided into: controls (n 7) and treated (n 7), receiving hydrocortisone (10 mg/kg iv after RF) and prednisone (1 mg/kg/day) for 29 days. After 8 months, animals were sacrificed for histological analysis. in four piglets, endocardial and epicardial voltage EAM were performed.In infant groups, the dimensions of atrial (11 +/- 5 vs. 13 +/- 7 mm) and ventricular (12 +/- 3 vs. 11 +/- 3 mm) lesions were similar. in adults, atrial (6 +/- 1 mm) and ventricular (6 +/- 1 mm) lesions were smaller. in controls, ventricular lesions depicted dense fibrosis and multiple strands of fibrous tissue extending from the lesion into normal muscle. Treated piglets revealed scars exhibiting less dense fibrosis with predominance of fibroadipose tissue and less collagen proliferation. Large atrial and ventricular low-voltage areas corresponding to the macroscopic lesions were identified in all animals.Conclusion Radiofrequency lesions in infant pigs reveal late growth and invasion of normal muscle by intense collagen proliferation. Corticosteroids do not prevent late enlargement of the lesions but modulate the fibrotic proliferation. the expressive growth of the lesion may generate low-voltage areas detectable by EAM.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, BrazilWeb of Scienc