Magnetic ground state and multiferroicity in BiMnO3_3

We argue that the centrosymmetric $C2/c$ symmetry in BiMnO$_3$ is spontaneously broken by antiferromagnetic (AFM) interactions existing in the system. The true symmetry is expected to be $Cc$, which is compatible with the noncollinear magnetic ground state, where the ferromagnetic order along one crystallographic axis coexists with the the hidden AFM order and related to it ferroelectric polarization along two other axes. The $C2/c$ symmetry can be restored by the magnetic field $B \sim 35$ Tesla, which switches off the ferroelectric polarization. Our analysis is based on the solution of the low-energy model constructed for the 3d-bands of BiMnO$_3$, where all the parameters have been derived from the first-principles calculations. Test calculations for isostructural BiCrO$_3$ reveal an excellent agreement with experimental data.Comment: 5 pages, 5 figure

Trabalho assalariado na agricultura paulista: evolução e importância no período 2004?2014.

Em 2014, do total de 702 mil pessoas com mais de 10 anos de idade e ocupadas em atividades agrícolas no estado de São Paulo, 460 mil eram empregados (permanentes e temporários). Também vale ressaltar que, no período 2004?2014, a população economicamente ativa (PEA) agrícola paulista ocupada sofreu fortíssima redução de 328 mil pessoas (taxa de -3,7% ao ano). E deste total, 187 mil (ou 57,1%) eram empregados. Em virtude disso, o objetivo do artigo é analisar a evolução e a importância desta categoria de trabalhadores na agricultura paulista no período 2004?2014, tendo como base de informações os dados primários da Pesquisa Nacional por Amostra de Domicílios (PNAD), realizada pelo Instituto Brasileiro de Geografia e Estatística (IBGE). Especial ênfase será dada para os seguintes aspectos do mercado de trabalho agrícola no período em questão: a queda contínua das ocupações na agropecuária; a masculinização da população economicamente ativa (PEA) ocupada nas atividades agrícolas; e o predomínio das relações de trabalho assalariado.Título em inglês: Wage labor force in the State of São Paulo?s agriculture: evolution and importance in the 2004-2014 period

Food losses and waste in the context of sustainable food systems

The issue of global food losses and waste has recently received much attention and has been given high visibility. According to FAO, almost one-third of food produced for human consumption – approximately 1.3 billion tonnes per year – is either lost or wasted globally: their reduction is now presented as essential to improve food security and to reduce the environmental footprint of food systems. In this context, the Committee on World Food Security (CFS), in its Thirty-ninth Session (October 2012) requested the High Level Panel of Experts on Food Security and Nutrition (HLPE) to undertake a study on “Food losses and waste in the context of sustainable food systems” to be presented to the CFS Plenary in 2014. The very extent of food losses and waste invites to consider them not as an accident but as an integral part of food systems. Food losses and waste are consequences of the way food systems function, technically, culturally and economically. This report analyses food losses and waste in a triple perspective: a systemic perspective, a sustainability perspective, including the environmental, social and economic dimensions of sustainability, and a food security and nutrition perspective, looking at how food losses and waste relate to the various dimensions of food security and nutritio

Antiferrodistortive phase transition in EuTiO3

X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis (a0a0c- in Glazer notation). The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples electron diffraction revealed an incommensurate tetragonal structure with modulation wavevector q ~ 0.38 a*. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects like Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.Comment: PRB, in pres

Biocide Susceptibility and Antimicrobial Resistance of Escherichia coli Isolated from Swine Feces, Pork Meat and Humans in Germany

Phenotypic susceptibility testing of Escherichia (E.) coli is an essential tool to gain a better understanding of the potential impact of biocide selection pressure on antimicrobial resistance. We, therefore, determined the biocide and antimicrobial susceptibility of 216 extended-spectrum β-lactamase-producing (ESBL) and 177 non-ESBL E. coli isolated from swine feces, pork meat, voluntary donors and inpatients and evaluated associations between their susceptibilities. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of benzalkonium chloride, chlorhexidine digluconate (CHG), chlorocresol (PCMC), glutaraldehyde (GDA), isopropanol (IPA), octenidine dihydrochloride and sodium hypochlorite (NaOCl) showed unimodal distributions, indicating the absence of bacterial adaptation to biocides due to the acquisition of resistance mechanisms. Although MIC95 and MBC95 did not vary more than one doubling dilution step between isolates of porcine and human origin, significant differences in MIC and/or MBC distributions were identified for GDA, CHG, IPA, PCMC and NaOCl. Comparing non-ESBL and ESBL E. coli, significantly different MIC and/or MBC distributions were found for PCMC, CHG and GDA. Antimicrobial susceptibility testing revealed the highest frequency of resistant E. coli in the subpopulation isolated from inpatients. We observed significant but weakly positive correlations between biocide MICs and/or MBCs and antimicrobial MICs. In summary, our data indicate a rather moderate effect of biocide use on the susceptibility of E. coli to biocides and antimicrobials

Relações de coordenação na cadeia produtiva dos produtos minimamente processados.

Os produtos minimamente processados (PMP) são alimentos práticos e nutritivos e cada vez mais demandados. Sua cadeia produtiva necessita de monitoramento em todos os elos, principalmente quando à qualidade, sanidade e prazo de validade. Este trabalho analisa as relações de coordenação entre os segmentos de produção agrícola, processamento e distribuição. O texto mostra que os processadores de PMP formam cinco grupos estratégicos, cujas dimensões estratégicas principais são custos, preços, qualidade, liderança tecnológica e canais de distribuição e que compreendem basicamente duas diferentes estruturas de governança (a híbrida e a de mercado); esses processadores têm tamanhos diferentes e atendem a diversos canais de distribuição. Os canais de distribuição, que são o varejo moderno, o mercado institucional (restaurantes, caterings, fast-foods, hospitais e hotéis) e canais alternativos de distribuição de PMP (feiras-livres, "sacolões", CEASAs e lojas de conveniência), comandam a dinâmica da cadeia e estabelecem os padrões exigidos para os PMP. Há cada vez mais uma necessidade de certificação de origem, orgânica, qualidade, etc, para que os vários elos possam ter segurança do que adquirem e dar garantias aos consumidores finais. O texto termina com propostas de diretrizes de políticas que podem auxiliar o desenvolvimento dos negócios desta cadeia produtiva, como o comércio local, certificação participativa, criação de redes de fornecimento e marca própria

Delineating Geographical Regions with Networks of Human Interactions in an Extensive Set of Countries

Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions.National Science Foundation (U.S.)Singapore-MIT Alliance for Research and Technolog