2,001 research outputs found
Dialogue between social movement activists and a Master's Program in youth and adult education
This article presents the results of a qualitative study on the relationship between social movements and a Master's Program in youth and adult education in Bahia, Brazil. It pays particular attention to the importance of antiracism in and the decolonization of the program's curriculum
WOOD BASIC DENSITY EFFECT OF Eucalyptus grandis x Eucalyptus urophylla CLONES ON BLEACHED PULP QUALITY
O estudo analisou a influ\ueancia da densidade b\ue1sica de dois
clones do h\uedbrido de Eucalyptus grandis x Eucalyptus urophylla
(440 kg/m3 e 508 kg/m3) na qualidade da polpa branqueada
(dimens\uf5es de fibras e propriedades f\uedsico-mec\ue2nicas). O
desempenho das madeiras nos resultados da polpa\ue7\ue3o,
branqueamento e refino foram analisados. As polpa\ue7\uf5es Kraft
foram realizadas em digestor de circula\ue7\ue3o for\ue7ada para
obten\ue7\ue3o de n\ufameros kappa de 17 \ub1 1. As polpas
n\ue3o-branqueadas foram submetidas a uma
pr\ue9-deslignifica\ue7\ue3o com oxig\ueanio e branqueadas pela
seq\ufc\ueancia D0EOPD1 visando \ue0 alvura de 90 \ub1 1. Os
resultados obtidos mostraram que a polpa branqueada do clone de menor
densidade b\ue1sica apresentou, significativamente, menor n\ufamero
de revolu\ue7\uf5es no moinho PFI para atingir o \uedndice de
tra\ue7\ue3o de 70 N.m/g, baixo grau. Schopper Riegler, para
atingir esse n\uedvel de tra\ue7\ue3o, gerou folhas com valores
mais elevados de volume espec\uedfico e opacidade. Essas
caracter\uedsticas e propriedades permitem concluir que a polpa do
clone de menor densidade foi mais indicada para a fabrica\ue7\ue3o
de pap\ue9is de imprimir e escrever. A polpa branqueada do clone de
maior densidade b\ue1sica apresentou valores mais elevados de volume
espec\uedfico aparente, ascens\ue3o capilar Klemm e menor
\uedndice de reten\ue7\ue3o de \ue1gua quando analisada sem
refino. A polpa branqueada do clone de maior densidade b\ue1sica
mostrou caracter\uedsticas mais favor\ue1veis para a
fabrica\ue7\ue3o de pap\ue9is para fins sanit\ue1rios.The study analyzed the wood basic density effect in two Eucalyptus
grandis x Eucalyptus urophylla hybrid clones (440 kg/m3 e 508 kg/m3
bleached pulp quality (fiber dimensions and physical-mechanical
properties). The woods performance on pulping, bleaching and beating
results were analyzed. The Kraft pulping was carried out in forced
circulation digester in order to obtain 17\ub11 kappa number targets.
The pulps were bleached to 90\ub11 using delignification oxygen and
D0EOPD1 bleaching sequence. Bleached pulp of low basic density clone
showed, significantly, lowest revolutions number in the PFI mill to
reach tensile index of 70 N.m/g, low Schopper Riegler degree and
generated sheets with higher values to bulk and opacity. These
characteristics and properties allow concluding that bleached pulp of
low basic density clone was the most indicated to produce printing and
writing sheets. The bleached pulp of high basic density clone showed
higher values of bulk and capillarity Klemm and lower water retention
value when analyzed without beating. The bleached pulp of high basic
density clone showed more favorable characteristics to the production
of tissue papers
Spillover events of rabbit haemorrhagic disease virus 2 (recombinant GI.4P-GI.2) from Lagomorpha to Eurasian badger
Rabbit haemorrhagic disease (RHD) is a major threat to domestic and wild European rabbits. Presently, in Europe, the disease is caused mainly by Rabbit haemorrhagic disease virus 2 (RHDV2/b or Lagovirus europaeus GI.2), the origin of which is still unclear, as no RHDV2 reservoir hosts were identified. After the RHDV2 emergence in 2010, viral RNA was detected in a few rodent species. Furthermore, RHDV2 was found to cause disease in some hare species resembling the disease in rabbits, evidencing the ability of the virus to cross the species barrier.
In this study, through molecular, histopathologic, antigenic and morphological evidences, we demonstrate the presence and replication of RHDV2 in Eurasian badgers (Meles meles) found dead in the district of SantarĂŠm, Portugal, between March 2017 and January 2020. In two of these seven animals, we further classify the RHDV2 as a Lagovirus europaeus recombinant GI.4PâGI.2.
Our results indicate that Meles meles is susceptible to RHDV2, developing systemic infection, and excreting the virus in the faeces. Given the high viral loads seen in several organs and matrices, we believe that transmission to the wild rabbit is likely.
Furthermore, transmission electron microscopy data shows the presence of Calicivirus compatible virions in the nucleus of hepatocytes, which has not been demonstrated before and constitutes a paradigm shift for calicivirusesâs replication cycle
Synthesis of hydrogels of cellulose acetate (AC) cross-linked with 3,3?,4,4? benzophenonetetracarboxylic dianhydride (BTDA) : characterization and adsorption physicochemical study.
Este trabalho descreve as s?nteses de hidrog?is superabsorventes a base de acetato de celulose (AC), com grau de substitui??o 2.5, reticulado com dianidrido 3, 3?, 4, 4? benzofenona tetracarbox?lico (BTDA). As caracteriza??es das mat?rias primas foram realizadas por an?lises t?rmicas (TG/DTG) e espectroscopia na regi?o do infravermelho (FTIR). O grau de substitui??o do acetato de celulose foi determinado por via ?mida. A confirma??o da rea??o de esterifica??o foi poss?vel a partir da t?cnica de FTIR, espectroscopia UV-vis e an?lises t?rmicas (TG/DTG). A presen?a de poros no novo material foi analisada por microscopia eletr?nica de varredura (MEV) e porosimetria (BET). A influ?ncia da concentra??o de dianidrido no meio reacional foi investigada, bem como a influ?ncia do aumento no grau de reticula??o no comportamento t?rmico do material. Foram obtidas isotermas de absor??o de ?gua em diferentes temperaturas para os hidrog?is com diferentes graus de reticula??o. Os coeficientes de difus?o dos g?is foram determinados, juntamente com a energia de ativa??o para o processo de inchamento usando a equa??o de Arrhenius. A entalpia de mistura do sistema gel-?gua foi determinada pela medida da quantidade m?xima de ?gua absorvida no equil?brio a diferentes temperaturas, empregando a equa??o de Gibbs/Helmholtz.This work describes the synthesis of hydrogels of cellulose acetate (AC), with a nominal degree of substitution DS = 2.5, cross-linked with 3,3?,4,4? benzophenonetetracarboxylic dianhydride (BTDA). The raw materials were characterized by thermal analysis (TG/DTG) and by Fourier transform infrared spectroscopy (FTIR). DS of cellulose acetate was determined by titration with a known amount of standard NaOH solution. Hydrogels of BTDA were synthesized with 0.5, 0.75 and 1.0 mol of BTDA/mol of AC. FTIR proved to be a suitable method to monitor the course of reactions and the progress of purification. UV-vis spectroscopy and analysis confirmed the esterification of the free hydroxyl groups. Surface modification of AC structure after the cross-linking reaction was analyzed by Scanning Electron Microscope (SEM) and density and porosity of the hydrogels were determined by BET. The influence of the concentration of dianhydride on the time necessary for formation of the gel was investigated. The influence from the increase in the degree of cross-linking on the thermal behavior of the material was also documented. Water absorption isotherms were obtained for hydrogels with different reticulating agents and reticulation degrees at different temperatures. The Arrhenius equation was used to determine the diffusion coefficient of the different hydrogels at distinct temperatures and the threshold energy for the swelling process. The enthalpy of mixture was determined through the measurement of the maximum quantity of water absorbed at equilibrium at different temperatures, with the Gibbs/Helmholtz equation
Lipidic characterization of Santa Ines lamb shoulder
The edible portion of the shoulder of 12 castrated and 12 non-castrated Santa Ines lambs slaughtered at different ages (84, 168, 210, 252 days) were used. The shoulders were chemically analyzed to determine the quantity of total lipids, cholesterol, and fatty acids composition. Castrated and non-castrated lambs gained body weight (p = 0.0393, p = 0.0017) and half carcass weight (p = 0.0240, p = 0.0017), respectively. The shoulder weight was increased in the carcasses of non-castrated lambs (p = 0.0110). The edible portion of the shoulder of castrated lambs presented higher total lipids (16.09 g.100 g(-1)). The cholesterol content was influenced by castration (p = 0.0001) reducing with age. Castrated animals presented higher content of C18:1 T11, CLA, and C18:0. The shoulder weight is only increased with increasing age in the carcasses of non-castrated lambs. Castration influences the cholesterol content of the shoulder; however, both castrated and non-castrated lambs had their cholesterol contents reduced with increasing age. Castration and age interfered in the estearic acid concentration of the edible portion of lamb shoulder.31250851
Critical teacher education : on socially responsible language teaching.
Neste trabalho, objetivamos apresentar resultados de pesquisas e propostas de atua??o de integrantes do N?cleo Parceiro de Belo Horizonte e Regi?o, filiado ao Projeto Nacional de Forma??o de Professores nas Teorias dos Novos Letramentos e Multiletramentos, coordenado pela Profa. Dra. Walkyria Monte M?r e pelo Prof. Dr. Lynn Mario Trindade Menezes de Souza. Primeiramente faremos uma r?pida retrospectiva da ?rea de forma??o de professores e discutiremos quest?es voltadas para o ensino cr?tico de l?nguas, j? que este tem sido o foco das pesquisas realizadas pelo n?cleo. Depois, ser?o discutidos trabalhos realizados por membros do n?cleo envolvendo a forma??o inicial de professores, a forma??o continuada e o ensino de l?nguas dentro da perspectiva da educa??o para as rela??es ?tnico-raciais, buscando desenvolver um senso de responsabilidade em rela??o a quest?es cr?ticas em nossa sociedade atual. Nos tr?s casos, as pesquisas e propostas foram sempre realizadas dentro da perspectiva cr?tica para o ensino de l?nguas, perspectiva essa adotada pelo Projeto Nacional. Por fim, conclu?mos o texto argumentando que os programas de forma??o de professores precisam criar espa?os para os professores repensarem suas pr?ticas e desenvolverem novas atitudes e perspectivas que lhes permitam atuar criticamente pela constru??o de sociedades menos injustas e menos desiguais.In this paper, we aim to present research results and proposals for practice put forward by members of the Partner Nucleus of Belo Horizonte and Region, affiliated to the National Project for Teacher Development in the Theories of New Literacies and Multiliteracies, coordinated by Prof. Walkyria Monte M?r and Prof. Lynn Mario Trindade Menezes de Souza. First, we will do a quick retrospective of the area of teacher education and discuss issues related to critical language teaching, since these have been the focus of the research carried out by the nucleus. Then we will discuss research and practices carried out by core members involving pre-service teacher education, inservice teacher education and language teaching from the perspective of education for ethnic-racial relations, seeking to develop a sense of responsibility for critical issues in our society. In all three cases, research and proposals were always carried out within the critical perspective for language teaching, a perspective adopted by the National Project. Finally, we conclude the text by arguing that teacher development programs need to create spaces for teachers to rethink their practices and develop new attitudes and perspectives that enable them to act critically by building less unjust and less unequal societies
KRAFT AND KRAFT/AQ PULPING FROM PREHIDROLYZED WOOD OF HYBRID Eucalyptus urophylla x grandis
A madeira do g\ueanero Eucalyptus ocupa um lugar de destaque em
rela\ue7\ue3o a outras fontes de celulose, devido a sua
composi\ue7\ue3o qu\uedmica, seu baixo custo, abund\ue2ncia e
disponibilidade. Dentre os processos de polpa\ue7\ue3o
qu\uedmica, o processo kraft \ue9 o mais extensivamente utilizado
para produ\ue7\ue3o de polpas celul\uf3sicas a partir da madeira
de eucalipto. O uso de antraquinona (AQ) na polpa\ue7\ue3o tem como
principais finalidades aumentar a taxa de deslignifica\ue7\ue3o,
bem como proteger a polpa quanto \ue0 degrada\ue7\ue3o dos
polissacar\ueddeos. O presente trabalho objetivou utilizar a
antraquinona como aditivo no cozimento visando reduzir a carga de
sulfidez aplicada no processo sem prejudicar a qualidade da polpa. Os
cozimentos kraft e kraft/AQ foram realizados em digestor rotativo
laboratorial variando-se inicialmente o \ue1lcali ativo (10, 13, 16 e
19%) e, posteriormente, a sulfidez (5, 10, 15, 20 e 25%), mantendo-se
as demais condi\ue7\uf5es constantes visando obter polpa com
n\ufamero kappa pr\uf3ximo de 9. A partir da varia\ue7\ue3o do
\ue1lcali ativo e da sulfidez foram estabelecidas curvas de
deslignifica\ue7\ue3o entre \ue1lcali ativo e n\ufamero kappa
e, sulfidez e n\ufamero kappa, de onde foi poss\uedvel estabelecer
as quantidades m\uednimas necess\ue1rias de \ue1lcali, bem como
de sulfidez. A partir dos cozimentos foi poss\uedvel estabelecer as
cargas de \ue1lcali ativo e sulfidez de 17,4% e 8,8%,
respectivamente. O cozimento em condi\ue7\uf5es determinadas
apresentou rendimento depurado de 48,63%, sendo que o rendimento com
base na massa inicial de madeira foi de 42,24%, gerando uma polpa de
elevada qualidade, ou seja, com baixo n\ufamero kappa e teor de
hemiceluloses (0,41%) e elevado teor de alfa celulose (98,49%).The wood of the gender Eucalyptus occupies a prominence place among
other cellulose sources due to its chemical composition, its low cost,
abundance and availability. Among the chemical pulping processes, kraft
process is the most extensively one used for the production of
cellulosic pulps starting from eucalyptus wood. The anthraquinone (AQ)
usage in the pulping has as main purposes to increase the
delignification rate as well as to protect the pulp from the
carbohydrate degradation. The present work has aimed to use the
anthraquinone as an addictive in the cooking seeking to reduce the load
of applied sulphidity without harming the quality of the pulp. The
kraft and kraft/AQ cooking were accomplished in rotative laboratorial
digester being varied the active alkali initially (10, 13, 16 and 19%)
and, later, the sulphidity (5, 10, 15, 20 and 25%), maintaining the
other conditions constant aiming to obtain pulp with kappa number close
to nine. Starting from the variation of the active alkali and of the
sulphidity, delignification curves were established between active
alkali and kappa number and, sulphidity and kappa number, where it was
possible to establish the minimum necessary amounts of alkali, as well
as of the sulphidity. Starting from the cooking, it was possible to
establish the active alkali and sulphidity loads of 17,4% and 8,8%,
respectively. The cooking to the certain conditions presented screened
yield of 48,63%, and the yield based on the initial mass of wood was of
42,24%, obtaining a high quality pulp, in other words, with low number
kappa and hemicelluloses tenor (0,41%) and high tenor of alpha
cellulose (98,49%)
Mitochondrial echoes of first settlement and genetic continuity in El Salvador
Background: From Paleo-Indian times to recent historical episodes, the Mesoamerican isthmus played an important role in the distribution and patterns of variability all around the double American continent. However, the amount of genetic information currently available on Central American continental populations is very scarce. In order to shed light on the role of Mesoamerica in the peopling of the New World, the present study focuses on the analysis of the mtDNA variation in a population sample from El Salvador.
Methodology/Principal Findings: We have carried out DNA sequencing of the entire control region of the mitochondrial DNA (mtDNA) genome in 90 individuals from El Salvador. We have also compiled more than 3,985 control region profiles from the public domain and the literature in order to carry out inter-population comparisons. The results reveal a predominant Native American component in this region: by far, the most prevalent mtDNA haplogroup in this country (at ~90%) is A2, in contrast with other North, Meso- and South American populations. Haplogroup A2 shows a star-like phylogeny and is very diverse with a substantial proportion of mtDNAs (45%; sequence range 16090â16365) still unobserved in other American populations. Two different Bayesian approaches used to estimate admixture proportions in El Salvador shows that the majority of the mtDNAs observed come from North America. A preliminary founder analysis indicates that the settlement of El Salvador occurred about 13,400Âą5,200 Y.B.P.. The founder age of A2 in El Salvador is close to the overall age of A2 in America, which suggests that the colonization of this region occurred within a few thousand years of the initial expansion into the Americas.
Conclusions/Significance: As a whole, the results are compatible with the hypothesis that today's A2 variability in El Salvador represents to a large extent the indigenous component of the region. Concordant with this hypothesis is also the observation of a very limited contribution from European and African women (~5%). This implies that the Atlantic slave trade had a very small demographic impact in El Salvador in contrast to its transformation of the gene pool in neighbouring populations from the Caribbean facade
A review exploring the overarching burden of Zika virus with emphasis on epidemiological case studies from Brazil
This paper explores the main factors for mosquito-borne transmission of the Zika virus by focusing on environmental, anthropogenic, and social risks. A literature review was conducted bringing together related information from this genre of research from peer-reviewed publications. It was observed that environmental conditions, especially precipitation, humidity, and temperature, played a role in the transmission. Furthermore, anthropogenic factors including sanitation, urbanization, and environmental pollution promote the transmission by affecting the mosquito density. In addition, socioeconomic factors such as poverty as well as social inequality and low-quality housing have also an impact since these are social factors that limit access to certain facilities or infrastructure which, in turn, promote transmission when absent (e.g., piped water and screened windows). Finally, the paper presents short-, mid-, and long-term preventative solutions together with future perspectives. This is the first review exploring the effects of anthropogenic aspects on Zika transmission with a special emphasis in Brazil
- âŚ