Rate adaptive resource allocation with fairness control for OFDMA networks

The use of opportunistic radio resource allocation techniques in order to efficiently manage the resources generates a low fairness among the users in a cellular system due to uneven Quality of Service (QoS) distribution. Some classic rate adaptive policies tried to tackle this problem for OFDMA systems by proposing solutions to maximize capacity, maximize fairness, or find a static trade-off between these two objectives. This work generalizes these classic policies and propose a dynamic fairness/rate adaptive technique based on dynamic sub-carrier assignment and equal power allocation that considers a new fairness constraint in the optimization problem. By means of extensive system-level simulations, it is demonstrated that the proposed technique is able to provide an instantaneous (short-term) fairness control, which provides to the network operator the flexibility to operate on any desired trade-off point.Peer ReviewedPostprint (published version

Slope Processes, Mass Movement and Soil Erosion: A Review

Soil erosion and land degradation are global problems and pose major issues in many countries. Both soil erosion and mass movement are two forms of land degradation and humans play important roles in these geomorphological processes. This paper reviews slope processes associated with mass movement and soil erosion and contributory factors, including physical and human agents. Acting together, these cause diverse geomorphological features. Slope processes are illustrated by reference to case studies from Brazil and UK. The causes and impacts of erosion are discussed, along with appropriate remedial bioengineering methods and the potential of the measures to prevent these types of environmental degradation. Although there are several agents of erosion, water is the most important one. Cultivation can promote soil erosion, due to ploughing and harvesting, which moves soil down slopes. Soil erosion and mass movement data would inform the viability of soil conservation practices. Integrated management of drainage basins offers a promising way forward for effective soil conservation and soil remedial bioengineering in Brazil and UK

Combination of Kato–Katz faecal examinations and ELISA to improve accuracy of diagnosis of intestinal schistosomiasis in a low-endemic setting in Brazil

Considering the decrease of disease burden caused by intestinal schistosomiasis in many endemic settings, more sensitive diagnostic methods are needed to plan and monitor control measures. We conducted a cross-sectional survey in a rural community in northeast Brazil (317 inhabitants). A combined approach including repeated faecal examinations and ELISA testing was applied. In a first round, single stool samples were collected from 305 (96.2%) participants. Three Kato–Katz (KK) smears were prepared from each sample, and IgG ELISA was performed from serum samples. In the 85 cases of negative KK smears, but positive ELISA results, three additional faecal samples were collected in a second round, and another five KK smears prepared. In the first round of KK analysis, 11/287 (3.8%; 95% confidence interval; 1.92–6.75) were positive. After examining up to eight smears per individual (second round), prevalence of schistosomiasis increased to 8.7% (95% confidence interval: 5.9–12.5). In total, 96/287 (33.4%, 95% confidence interval: 28.0–39.2) samples were positive by ELISA testing. There were no false negative ELISA results. Specificity, positive and negative predictive values of ELISA as compared to up to eight KK smears from three stool samples (reference diagnosis) were 72.9%, 26.0% and 100%, respectively. A single KK smear detected only 12% of the 25 infections; this increased to 44% (three smears, one stool sample), 84% (five smears, three stool samples) and 96% (six smears, four stool samples). We conclude that in low-endemic areas in Brazil the use of KK continues being an important tool. The additional benefit of preparing more than six KK smears from repeated stool samples is negligible. ELISA may be useful for screening populations, with subsequent confirmation of diagnosis by KK or other more sensitive, but highly specific methods

The Learning Model Based in Piaget, Vygotsky and Freire: a proposal to overcome the reading difficulties of 5th grade students on schools on the Brazilian

It is a worrying factor the results presented in the process of reading the 5th-grade students of the Brazilian schools. Many students indicate weaknesses in reading skills. Thus, it becomes important to resort to the theories of learning presented by the authors: Jean Piaget (1896-1980), Lev Vygotsky (1896-1934) and Paulo Freire (1921-1997), in an attempt to understand mechanisms of teacher practice that make possible the construction of the student\u27s cognitive process and reading abilities. Finally, we propose the creation of a learning model based on the three theories presented

Origin and distribuition of sciatic nerves of the Galea

O preá do semiárido nordestino (Galea spixii Wagler, 1831) é um roedor pertencente à família Caviidae. Pouca literatura é encontrada sobre essa espécie em relação a sua morfologia e seu comportamento ambiental e reprodutivo. Com o objetivo de entender a morfologia geral, em foco, na inervação do membro pélvico dessa espécie, neste trabalho, foi explorado o nervo isquiático, o qual é o maior de todos os nervos do organismo. Foram utilizados 10 preás (cinco machos e cinco fêmeas) que vieram a óbito por causas naturais, oriundos do Centro de Multiplicação de Animais Silvestres da Universidade Federal Rural do Semiárido (CEMAS/UFERSA). Os animais foram fixados após o óbito em solução aquosa de formaldeído 10% e, após 48 horas de imersão nessa solução, foram dissecados para exposição do nervo isquiático. Dessa forma, os dados obtidos foram compilados em tabelas e expressos em desenhos esquemáticos e fotografias. Os pares de nervos isquiáticos originaram-se de raízes ventrais de L6L7S1 (70%) e de L7S1S2 (30%) e distribuíram-se pelos músculos glúteo profundo, bíceps femural, semitendinoso e semimembranoso.The Galea of the semi-arid northeast (Galea spixii Wagler, 1831) is a rodent belonging to the family Caviidae. Little literature is found on this species in relation to morphology, environmental and reproductive behavior. With a view to understanding the general morphology, particularly, in the innervation of the pelvic limb of this species, ponder the sciatic nerve, which is the largest of all the nerves of the body. 10 cavies were used (five males, five females) that they had died of natural causes, originating from breeders scientific, legally licensed by IBAMA, the UFRSA, Mossoró, RN. The animals were fixed after the death in an aqueous solution of formaldehyde 10% and after 48 hours of immersion in it, were dissected to expose the sciatic nerve. Thus, the data were compiled in tables and expressed in drawings and photographs. The pairs of sciatic nerves were derived from ventral roots L6L7S1 (70%) and L7S1S2 (30%) and were distributed by the deep gluteal muscles, biceps femural, semitendinosus and semimembranosus muscles

Atributos químicos de Argissolo após gessagem e cultivo de cana-de-açúcar

A gessagem pode aumentar a produtividade das culturas por reduzir os teores de alumínio tóxico e suprir nutrientes como o Ca2+, SO42- e Mg2+ às plantas. Este estudo teve como objetivo avaliar os atributos químicos de um Argissolo após aplicação de gesso em área de cultivo de cana de açúcar. O delineamento experimental foi em blocos casualizado e os tratamentos foram constituídos das doses de 0; 0,325; 0,65; 1,3 e 2,6 Mg ha-1 de gesso mineral.  Após 30 dias da aplicação do gesso no sulco de plantio da cana-de-açúcar foram abertas trincheiras e nas camadas de 0 a 0,3 m, 0,3 a 0,6 m e 0,6 a 0,9 m foram coletadas amostras para análise dos atributos químicos. A gessagem reduziu os teores e a saturação de Al3+ na camada de 0 a 0,3 m, e as doses de 0,325 e 2,5 Mg ha-1 foram efetivas em aumentar os teores de SO42- e Mg2+ em subsuperfície respectivamente. Entretanto, não houve aumento nos teores de Ca2+ em subsuperfície e alterações consideráveis do pH nas camadas avaliadas

ANÁLISE GEOMORFOLÓGICA E PROCESSOS EROSIVOS ACELERADOS NA BACIA HIDROGRÁFICA DO RIO TIBIRI, ILHA DO MARANHÃO

A Geomorfologia tem como finalidade analisar as formas de relevo e os processos ocorrentes, sendo uma ciência fundamental para auxiliar a gestão e o planejamento urbano e ambiental, já que a ocupação inadequada de ambientes urbanos tem aumentado progressivamente. Assim, o objetivo desta pesquisa é analisar os fatores geoambientais, com ênfase à geomorfologia, em relação aos processos erosivos acelerados na bacia do rio Tibiri, localizada na Ilha do Maranhão, a partir da elaboração de mapeamento geomorfológico subsidiado na classificação taxonômica de Ross (1992). As formas de relevo encontradas na bacia são equivalentes ao terceiro até o sexto táxon, sendo o último correspondente às formas erosivas, que recebem influência dos táxons antecessores e suas morfologias. Por meio do levantamento bibliográfico e cartográfico, trabalhos de campo e de gabinete, foram analisados processos erosivos em alto estágio de evolução, como as voçorocas Vila Santana, Matadouro, Cemitério e Cemitério II, além do processo de urbanização com a fixação de residências em localidades frágeis do ponto de vista ambiental. Portanto, percebe-se a necessidade de planejar a ocupação da área, considerando a intensidade dos processos morfodinâmicos e a premência de técnicas para a prevenção e sua consequente conservação.