Changes in fire regimes since the Last Glacial Maximum: an assessment based on a global synthesis and analysis of charcoal data

Fire activity has varied globally and continuously since the last glacial maximum (LGM) in response to long-term changes in global climate and shorter-term regional changes in climate, vegetation, and human land use. We have synthesized sedimentary charcoal records of biomass burning since the LGM and present global maps showing changes in fire activity for time slices during the past 21,000 years (as differences in charcoal accumulation values compared to pre-industrial). There is strong broad-scale coherence in fire activity after the LGM, but spatial heterogeneity in the signals increases thereafter. In North America, Europe and southern South America, charcoal records indicate less-than-present fire activity during the deglacial period, from 21,000 to ∼11,000 cal yr BP. In contrast, the tropical latitudes of South America and Africa show greater-than-present fire activity from ∼19,000 to ∼17,000 cal yr BP and most sites from Indochina and Australia show greater-than-present fire activity from 16,000 to ∼13,000 cal yr BP. Many sites indicate greater-than-present or near-present activity during the Holocene with the exception of eastern North America and eastern Asia from 8,000 to ∼3,000 cal yr BP, Indonesia and Australia from 11,000 to 4,000 cal yr BP, and southern South America from 6,000 to 3,000 cal yr BP where fire activity was less than present. Regional coherence in the patterns of change in fire activity was evident throughout the post-glacial period. These complex patterns can largely be explained in terms of large-scale climate controls modulated by local changes in vegetation and fuel load

Improving the fatty acid profile of winter milk from housed cows with contrasting feeding regimes by oilseed supplementation

Many studies show concentrations of nutritionally desirable fatty acids in bovine milk are lower when cows have no access to grazing, leading to seasonal fluctuations in milk quality if cows are housed for part of the year. This study investigated the potential to improve the fatty acid profiles of bovine milk by oilseed supplementation (rolled linseed and rapeseed) during a period of indoor feeding in both organic and conventional production systems. Both linseed and rapeseed increased the concentrations of total monounsaturated fatty acids, vaccenic acid, oleic acid and rumenic acid in milk, but decreased the concentration of the total and certain individual saturated fatty acids. Linseed resulted in greater changes than rapeseed, and also significantly increased the concentrations of α-linolenic acid, total polyunsaturated fatty acids and total omega-3 fatty acids. The response to oilseed supplementation, with respect to increasing concentrations of vaccenic acid and omega-3 fatty acids, appeared more efficient for organic compared with conventional diets.

The effects of maize planting density and weeding regimes on light and water use

Light and water are among essential resources required for production of photosynthates in plants. A study on the effects of weeding regimes and maize planting density on light and water use was conducted during the 2001/2 short and 2002 long rain seasons at Muguga in - the central highlands of Kenya. Weeding regimes were: weed free (W1), weedy (W2), herbicide (W3) and hand weeding twice (W4). Maize planting densities were 9 (D1) and 18 plants m-2 (D2) intercropped with Phaseolus vulgaris (beans). The experiment was laid as randomized complete block design replicated four times and repeated twice. All plots were thinned to 4 plants m-2 at tasseling stage (96 DAE) and thinnings quantified as forage. Soil moisture content (SMC), photosynthetically active radiation (PAR) interception, evapo-transpiration (ET crop), water use efficiency (WUE), and harvest index (HI), were determined. Percent PAR was higher in D2 than in D1 before thinning but higher in D1 than in D2 after thinning in both seasons. PAR interception was highest in W2 but similar in W1, W3 and W4 in both seasons. SMC was significantly lower in W2 but similar in W1, W3 and W4. D2 had lower SMC than D1 in season two. Weeding regime significantly influenced ET crop, while planting density and weeding regime significantly influenced WUE and HI. D2 maximizes water and light use for forage production but results to increased intra-specific plant competition for water and light severely before thinning (96 DAE) that reduce grain yield in dual purpose maize, relative to D1.

Characterisation of convective regimes over the British Isles

Convection-permitting modelling has led to a step change in forecasting convective events. However, convection occurs within different regimes which exhibit different forecast behaviour. A convective adjustment timescale can be used to distinguish between these regimes and examine their associated predictability. The convective adjustment timescale is calculated from radiosonde ascents and found to be consistent with that derived from convection-permitting model forecasts. The model-derived convective adjustment timescale is then examined for three summers in the British Isles to determine characteristics of the convective regimes for this maritime region. Convection in the British Isles is predominantly in convective quasi-equilibrium with 85%of convection having a timescale less than or equal to three hours. This percentage varies spatially with more non-equilibriumevents occurring in the south and southwest. The convective adjustment timescale exhibits a diurnal cycle over land. The nonequilibrium regime occurs more frequently at mid-range wind speeds and with winds from southerly to westerly sectors. Most non-equilibrium convective events in the British Isles are initiated near large coastal orographic gradients or on the European continent. Thus, the convective adjustment timescale is greatest when the location being examined is immediately downstream of large orographic gradients and decreases with distance from the convective initiation region. The dominance of convective quasiequilibrium conditions over the British Isles argues for the use of large-member ensembles in probabilistic forecasts for this region.

Quartz recrystallization regimes, c-axis texture transitions and fluid inclusion reequilibration in a prograde greenschist to amphibolite facies mylonite zone (Ribeira Shear Zone, SE Brazil)

The crystal-plastic behavior of quartz mylonites from the Ribeira Shear Zone (SE Brazil), a major strike-slip structure that was active during a prograde metamorphic phase related to the Neoproterozoic Brasiliano-Pan African Orogeny, was investigated using a multi-method approach. Geothermobarometry results indicate deformational conditions ranging from similar to 300 to similar to 630 degrees C and 500-700 MPa. A strong correlation between mapped metamorphic zones and a dominance of different dynamic recrystallization mechanisms of quartz occurs within the mylonite zone. Bulging recrystallization (BLG) dominates within the chlorite zone between 300 and 410 degrees C, subgrain rotation recrystallization (SGR) operates within the biotite zone from 410 to 520 degrees C, and grain boundary migration recrystallization (GBM) dominates in the garnet zone above 520 degrees C. The development of quartz c-axis textures is mainly governed by temperature and dynamic recrystallization mechanisms. Textures from BLG zone mylonites are characterized by maxima around Z; SGR zone mylonites display single girdles or asymmetric type I crossed girdles; and GBM zone mylonites comprise maxima around Y and intermediate between X and Z. The scarcity or absence of water-bearing fluid inclusions in quartz mylonites from the SGR and GBM zones, which are dominated by carbonic inclusions, suggests water-deficient conditions, whereas BLG zone mylonites are dominated by water-bearing inclusions. This evidence indicates that water was available in the protoliths but has been eliminated with increasing deformation and deformation temperature. No effect of the water content variation on the quartz microstructural and recrystallized grain size evolution was detected, and little influence on c-axis texture development was observed. Most of the fluid inclusion densities were reequilibrated during the shear zone exhumation history, recording a decompression in the range of 300-500 MPa, while microstructural reequilibration effects related to the prograde metamorphism are largely preserved. Fluid inclusion microstructures and densities from two SGR zone samples preserved evidence for a near isothermal compression within the interior of the Ribeira Shear Zone during the prograde metamorphism. (C) 2009 Elsevier B.V. All rights reserved.

No consensus on gestational diabetes mellitus screening regimes in Sweden : pregnancy outcomes in relation to different screening regimes 2011 to 2012, a cross-sectional study

Background: Although associated adverse pregnancy outcomes, no international or Swedish consensus exists that identifies a cut-off value or what screening method to use for definition of gestational diabetes mellitus. This study investigates the following: i) guidelines for screening of GDM; ii) background and risk factors for GDM and selection to OGTT; and iii) pregnancy outcomes in relation to GDM, screening regimes and levels of OGTT 2 hour glucose values. Methods: This cross-sectional and population-based study uses data from the Swedish Maternal Health Care Register (MHCR) (2011 and 2012) combined with guidelines for GDM screening (2011-2012) from each Maternal Health Care Area (MHCA) in Sweden. The sample consisted of 184, 183 women: 88, 140 in 2011 and 96,043 in 2012. Chi-square and two independent samples t-tests were used. Univariate and multivariate logistic regression analyses were performed. Results: Four screening regimes of oral glucose tolerance test (OGTT) (75 g of glucose) were used: A) universal screening with a 2-hour cut-off value of 10.0 mmol/L; B) selective screening with a 2-hour cut-off value of 8.9 mmol/L; C) selective screening with a 2-hour cut-off value of 10.0 mmol/L; and D) selective screening with a 2-hour cut-off value of 12.2 mmol/L. The highest prevalence of GDM (2.9%) was found with a 2-hour cut-off value of 8.9 mmol/L when selective screening was applied. Unemployment and low educational level were associated with an increased risk of GDM. The OR was 4.14 (CI 95%: 3.81-4.50) for GDM in obese women compared to women with BMI <30 kg/m(2). Women with non-Nordic origin presented a more than doubled risk for GDM compared to women with Nordic origin (OR = 2.24; CI 95%: 2.06-2.43). Increasing OGTT values were associated with increasing risks of adverse pregnancy outcomes. Conclusions: There was no consensus regarding screening regimes for GDM from 2011 through 2012 when four different regimes were applied in Sweden. Increasing levels of OGTT 2-hour glucose values were strongly associated with adverse pregnancy outcomes. Based on these findings, we suggest that Sweden adopts the recent recommendations of the International Association of Diabetes and Pregnancy Study Group (IADPSG) concerning the performance of OGTT and the diagnostic criteria for GDM.

Discursos e representações acerca da docência em história: os manuais de história para professores do ciclo II do ensino fundamental

O texto apresenta uma proposta de pesquisa sobre os manuais do professor para o ensino de história. Trata inicialmente dos objetivos e dos procedimentos da investigação para depois identificar os temas e as questões que estruturam a pesquisa. Por fim, foi intenção discutir as possibilidades do uso do conceito de “representação” para o estudo dos discursos acerca da docência em história. Manuais do professor, ensino de história, currículo

Os manuais do professor como fonte de pesquisa sobre o ensino de História.

Este artigo apresenta os resultados parciais de uma pesquisa sobre os Manuais dos Professores que acompanham as coleções didáticas de História recomendadas pelo PNLD-2008. Percebe o Manual do Professor como fonte de pesquisa a respeito das formas como se vêm tratando os paradigmas organizadores do discurso sobre as práticas do ensino da História. O estudo tem se detido na investigação do modo como são construídos os procedimentos didáticos nesses impressos e nos protocolos de leitura que operam sentido no uso do suplemento docente dos livros didáticos. Inicialmente, presta-se atenção no que se refere ao lugar de onde os autores se pronunciam. Também interessou perceber a distância entre quem escreve sobre a prática de ensino nos manuais do professor e os docentes que procuram dar sentido prático às orientações. Assim, procurei sistematizar as indicações sobre a titulação e a atuação profissional dos autores das coleções. Essas referências adiantam ao leitor o lugar social em que se posicionam os autores de livros didáticos, indicando as funções que ocupam e as instituições a partir das quais se enunciam. A sistematização disso permitiu identificar algo sobre quem está escrevendo as obras didáticas e em quais circunstâncias o tem feito. A reflexão é concluída com uma abordagem do tipo de discurso utilizado para veiculação de técnicas de aprendizagem, sugestões de trabalho, exercícios e tarefas que os alunos devem desempenhar para a apreensão dos conteúdos. A análise dos suportes materiais da produção e da circulação dos impressos e da materialidade das práticas e usos da leitura tem evidenciado que os dispositivos de imposição de saberes e normatização de práticas se referem a lugares de poder determinados. Nesse sentido, tem-se percebido que na estruturação e nas condições de ensino que o Manual do Professor visa elaborar para os professores perpassa uma relação de autoridade que diz respeito às posições e às propriedades sociais objetivas de autores, docentes e alunos.

Os manuais do professor como fonte de pesquisa acerca da história ensinada.

Relatório técnico-científico parcial do projeto de pesquisa "Discursos e representações acerca da docência em história: perspectivas sobre o ensino de história no ciclo II da educação fundamental. Pesquisa que contou com o apoio da Coordenadoria de pesquisa da Universidade de São Caetano do Sul e com financiamento do CNPq e tem como propósito compreender o discurso dos manuais do professor publicados junto aos livros didáticos de história do Ciclo II do ensino fundamental

Os modos de enunciação nos manuais de ensino para professores de História

Este artigo consiste em um estudo sobre os modos de enunciação dos Manuais de Ensino para professores de História. Tomando como fontes de pesquisa os livros recomendados pelo Programa Nacional do Livro Didático de 2008 (PNLD-2008), o texto examina a configuração discursiva desse recurso didático. Os modos de enunciação nos Manuais do Professor são analisados considerando o gênero dos textos, a intenção discursiva dos autores e o modelo de docente; eles também são analisados como práticas de representação do ensino e da aprendizagem.

Perspectivas sobre a história ensinada

Relatório Científico do Projeto de Pesquisa “Discursos e Representações acerca da docência em História: perspectivas sobre o ensino de História no Ciclo II da Educação Fundamental”

História oral e estudos de comunicação e cultura

O artigo pretende discutir questões relacionadas às possibilidades de utilização dos métodos da história oral nas pesquisas empíricas em Comunicação. Também se propõe a discutir os atributos que tais pesquisas devem apresentar para que sejam pertinentes para o uso dessa metodologia. Uma das principais questões abordadas é sobre quais objetos ou fenômenos da Comunicação podem ser estudados tendo em vista a metodologia da História Oral. A partir dessa discussão,apontam-se quais as pesquisas de Comunicação que se abrem a essa possibilidade: aquelas que tenham preocupações relacionadas aos universos multiculturais, às identidades locais, às comunidades e às relações existentes entre as pessoas e os processos de comunicação, bem como usos e consumos midiáticos.

Memória e cidadania nos acervos de história oral e mídia digital

Este texto tem como proposta discutir a importância da constituição de acervos de história oral, levando em consideração a difusão da memória e o exercício da cidadania a partir dela, bem como as relações de poder envolvidas nesse processo. As técnicas de história oral possibilitam a organização de um acervo de relatos de história de vida que, no seu conjunto, levam à recuperação da identidade coletiva e da memória da comunidade. São os sentimentos de pertencimento a um grupo, garantido por imagens ou símbolos, que permitem o reconhecimento do outro como a si mesmo. Esse reconhecimento pode ser visualizado a partir da gravação sistemática (de som e imagem) de depoimentos de personagens singulares, atribuindo importância às minorias e destaque para os direitos e liberdades individuais.

Mudanças no uso da fotografia em livros de história e geografia para o ensino fundamental

Dissertação apresentada ao Programa de Pós-graduação em Comunicação - Mestrado da Universidade Municipal de São Caetano do Sul.