A rheological characterization of kappa-carrageenan/galactomannan mixed gels: a comparison of locust bean gum samples

Mixed gels of kappa-carrageenan and locust bean gum (LBG) obtained from different varieties of Portuguese carob trees and commercial gums were compared. The viscoelastic properties of the gels were measured using dynamic parallel-plate geometry. Mixed gels at 1·0% of total polysaccharide concentration without addition of KCl showed, whatever the LBG sample, a synergistic maximum when the ratio of kappa-carrageenan to LBG was 80/20 The amplitude of this maximum varied with the LBG sample. The gels prepared at 0·3% total concentration with KCl added, showed a synergistic maximum at the same mixing ratio and the amplitude varied in a similar manner. Each sample was fractionated into the fraction soluble at 25°C and the fraction soluble at 90°C. Mixed gels of kappa-carrageenan with cold-water-soluble and hot-water-soluble fractions, and also with tara gum and guar gum were prepared at the 80/20 ratio. It was found that the synergistic maxima were related to the intrinsic viscosity and the M/G ratio. A linear relationship between the storage modulus G′max at the synergistic maximum and the product of the intrinsic viscosity and the square of the mannose to galactose ratio was found, suggesting that the synergistic mechanism can be ascribed to both the unsubstituted (galactose-free) regions of the galactomannan and the molecular weight

Safety of frozen vegetables: a case study on carrots

Consumers are confident in frozen foods, which is a consequence of proven safety and quality characteristics of the products. However, safety depends strongly on the quality of the raw materials, the hygienic conditions when handling both at industrial and home processing, and on the temperature conditions during the entire logistic chain. Bacteria survival depends upon a number of factors, such as type of microorganism, freezing process, rate of freezing, storage temperatures and freeze-thaw cycles. The goal of this work was to quantify the impact of the freezing operation per si and frozen storage, at two temperatures (-7º and –20 ºC), on total aerobes, yeast and moulds levels on shredded carrots (Daucus carrota L.). Results showed that, for both temperatures analyzed, the freezing operation itself had a significant effect (p<0,05) in reducing microbial counts, when compared with the initial levels. Storage temperature did not influence significantly mesophilic aerobic flora levels (p<0,05). However, yeasts counts in samples stored at –20ºC presented a gradual decline along the storage period, being significantly lower than samples at -7ºC, after 10 days of storage. Moulds were not detected in all analyzed samples

As representações da comunidade cigana sobre a escola: o estudo de caso da comunidade do Bairro Dr. Alfredo Bensaúde

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Educação Social e Intervenção ComunitáriaEste trabalho de investigação centra-se numa problemática que visa compreender as representações que a comunidade cigana tem da escola, como forma de melhor intervir no sentido de promover a inclusão social dos seus filhos, sem pôr em causa os seus valores e práticas sociais que definem a sua identidade. Este estudo procura investigar, analisar e interpretar para compreender as vivências e a relação desta comunidade face à educação escolar, devido ao facto de haver constantes mudanças e transformações ao longo dos tempos. O estudo tem como principais objetivos, Conhecer a dimensão do fenómeno do absentismo entre as crianças ciganas no 1.º Ciclo do Ensino Básico; Reconhecer o significado atribuído pelos pais/ciganos ao papel da escola na educação dos seus filhos; Identificar os atributos da escola identificados pelas crianças ciganas; Conhecer as causas que os professores identificam para explicar o fenómeno do absentismo entre as crianças ciganas e Identificar as características atribuídas pelos professores às crianças ciganas no que se refere à sua forma de viver a escola. No plano teórico realizámos uma pesquisa relativamente à história das comunidades ciganas, à sua chegada a Portugal e especificamente à comunidade residente no Bairro Dr. Alfredo Bensaúde. Foram igualmente exploradas questões sobre a exclusão e integração da população cigana, nos diversos parâmetros da sociedade atual, com maior destaque na participação escolar. No processo de investigação utilizou-se a metodologia qualitativa, sendo que o seu instrumento foi o inquérito por questionário de administração indireta, pois esta permitiu conhecer uma opinião mais pessoal dos indivíduos, relativamente às representações sobre a comunidade cigana na escola. A pesquisa foi realizada no 1º Ciclo do Ensino Básico da escola n.º 175 Santa Maria dos Olivais. A amostra da investigação tem um total de cinquenta e nove indivíduos entrevistados, entre os quais quarenta e seis são crianças, seis são famílias ciganas, seis são professores e 1 técnico do Instituto de Apoio à Criança. Ao longo do estudo concluiu-se que o nível de absentismo e insucesso escolar por parte dos alunos ciganos continua a ser elevado, contudo, tem-se verificado uma melhoria no que diz respeito à duração escolar. A escola e as instituições envolventes têm tentado estar mais próximos da comunidade cigana, com o intuito de estes se aproximarem e interagirem com a sociedade escolar. Apesar de haver melhorias observa-se que ainda existe um longo caminho a percorrer e que existem etapas por alcançar.ABSTRACT This research focuses on a problem that aims to understand the representations that the gypsy community has of the school, as a way to better intervene to promote the social inclusion of their children, without undermining their values and social practices that define their identity. This study sought to investigate analyse and interpret to understand the experiences and the relation of this community face to school education, due to the fact that there have been constant changes and transformations throughout the ages. The main objectives of the study are: To know the dimension of the phenomenon of absenteeism among Roma children in the 1st Cycle of Basic Education; Recognize the significance attributed by the parents / gypsies to the role of the school in the education of their children; Identify the attributes of the school identified by gypsies children; To know the causes that the teachers identify to explain the phenomenon of absenteeism among the gypsy children and To identify the characteristics attributed by the teachers to the gypsy children with respect to their way of living the school. At the theoretical level, we carried out a survey on the history of Gypsy communities, their arrival in Portugal and specifically the community residing in the neighbourhood Dr. Alfredo Bensaúde. It also explored questions about the exclusion and integration of the gypsies population, in the various parameters of the current society, with greater prominence on school participation. In the research process the qualitative methodology was used, and its instrument was the questionnaire interview, since this allowed to know a more personal opinion of the individuals, regarding the representations about the gypsy community in the school. The research was carried out in the 1st Cycle of Basic Education of 175 Santa Maria dos Olivais School. The research sample has a total of fifty-nine individuals interviewed, among them forty-six are children, six are gypsy families, six are teachers and one is from the Institute for Child Support. Throughout the study it was concluded that the level of absenteeism and school failure by the gypsy students continues to be high, however, there has been an improvement with regard to school duration. The school and the surrounding institutions have tried to be closer to the gypsy community, with the intention of getting closer and interacting with the school society. Although there are improvements it is noted that there is still a long way to go and that there are steps to be taken.N/

Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito Anopheles gambiae

The mosquito Anopheles gambiae is a primary vector of Plasmodium parasites in Africa. The effect of aging on reproductive output in A. gambiae females from three strains that differ in their ability to melanize Plasmodium and in their systemic levels of hydrogen peroxide (H2O2), a reactive oxygen species (ROS), was analyzed. The number of eggs oviposited after the first blood meal decreases with age in all strains; however, this decline was much more pronounced in the G3 (unselected) and R (refractory to Plasmodium infection) strains than in the S (highly susceptible to Plasmodium) strain. Reduction of ROS levels in G3 and R females by administration of antioxidants reversed this age-related decline in fecundity. The S and G3 strains were fixed for two functionally different catalase alleles that differ at the second amino acid position (Ser2Trp). Biochemical analysis of recombinant proteins revealed that the Trp isoform has lower specific activity and higher Km than the Ser isoform, indicating that the former is a less efficient enzyme. The Trp-for-Ser substitution appears to destabilize the functional tetrameric form of the enzyme. Both alleles are present in the R strain, and Ser/Ser females had significantly higher fecundity than Trp/Trp females. Finally, a systemic reduction in catalase activity by dsRNA-mediated knockdown significantly reduced the reproductive output of mosquito females, indicating that catalase plays a central role in protecting the oocyte and early embryo from ROS damage