An alternative order parameter for the 4-state Potts model

We have investigated the dynamic critical behavior of the two-dimensional 4-state Potts model using an alternative order parameter first used by Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of the Z(5) model. We have estimated the global persistence exponent $\theta_g$ by following the time evolution of the probability $P(t)$ that the considered order parameter does not change its sign up to time $t$. We have also obtained the critical exponents $\theta$, $z$, $\nu$, and $\beta$ using this alternative definition of the order parameter and our results are in complete agreement with available values found in literature.Comment: 6 pages, 6 figure

Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry

In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO3. It is generally accepted that the main reason of the ferroelectric distortion in BiFeO3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic beta-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity - its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO3 in the range from 945 C down to 25 C and found the couplings, which undergo the antiferromagnetic-ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table

Produção orgânica de calêndula: um estudo de caso.

Apresenta-se caracterização do processo de produção agrícola orgânica de Calendula officinalis L. no Estado de Santa Catarina, evidenciando particularidades e discrepâncias frente aos modelos já descritos na literatura especializada, a partir de visitas a campo, observação participante e entrevistas com um produtor de plantas medicinais. Identificaram-se como principais particularidades a saúde na agricultura familiar, demonstrada pela prática da cultura orgânica, além do controle de pragas e manuseio da produção. Os principais problemas ou divergências evidenciados foram: características do solo; época de plantio da calêndula e suas etapas posteriores, como transplante e floração. Aspectos da colheita foram discrepantes quanto ao período do dia indicado para o procedimento, bem como a ausência de informações do produtor quanto à existência de outros incentivos governamentais ao setor agrícola. Recomenda-se aos extensionistas rurais e/ou instituições competentes que busquem orientar os produtores orgânicos de calêndula para promover a adequação das práticas de cultivo dessa espécie medicinal

Initial in vitro evaluations of antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria

Aims: The aim of the study was to evaluate the in vitro antibacterial effects of glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas juglandis. Methods and Results: Using a disc diffusion assay, seven different doses of 10 GHP were tested against each bacteria. The results showed that the isothiocyanates were potent antibacterials, whilst the other GHP were much less efficient. Moreover, the antibacterial effects were dose-dependent, increasing with the dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest inhibitory effects. The overall results show a great potential for using the isothiocyanates as an alternative tool to control undesired bacterial growth in plants. Conclusions: Glucosinolate hydrolysis products and more specifically the isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate Mix and sulforaphane, were effective phytochemicals against the in vitro growth of the phytopathogenic bacteria. The antibacterial activity exhibited by these phytochemicals reinforces their potential as alternatives to the traditional chemical control of phytopathogenic bacteria. Significance and Impact of the Study: This current in vitro study is the first providing comparative data on GHP as potential control agents for plant pathogenic bacteria. However, more studies are needed to determine their possible allelopathic impacts e.g. inhibition of plant growth and negative effects on beneficial soil bacteria and fungi (mycorrhizae

Resíduos de Serviços de Saúde Gerados em Unidades de Saúde de Pequeno Porte no Município de Jaú- SP: Geração e Disposição Final

Considerando a quantidade expressiva de resíduos gerados pelas unidades de saúde de pequeno porte, a preocupação crescente com o gerenciamento destes resíduos e a falta de investigações sobre o tema, este trabalho caracteriza a geração e disposição final dos Resíduos de Serviços de Saúde gerados em unidades de saúde de pequeno porte, no município de Jaú-SP