Mechanism for enhancement of electrical activation of silicon in GaAs by aluminum co-implantation

A pronounced enhancement in the electrical activation of implanted Si in GaAs is demonstrated by co-implantation of Al. The maximum enhancement ( x 2) occurs when the Si distribution is shallow, there is a separation between the Si and Al distributions with the Al being deeper, the Si and Al are implanted at doses of 91 X 1013 cme2, and subsequent annealing of the co-implanted GaAs is performed under capless or proximity cap conditions. A model considering gettering of the oxygen present in the bulk Czochralski-grown GaAs to the implanted Al is invoked to explain the observed activation enhancement

Metastable acceptor centers in boron implanted silicon

The evolution of the electrical activation with the annealing time in B1 implanted (5.0 31014 cm22, 50 keV! Si was studied as a function of the annealing temperature. Electrical activation yields of 15%–30% were observed after annealing for 2 s at temperatures above 550 °C. Prolonging the annealing time from 2 to 900 s we observed that the electrical activation evolves differently according to the temperature: ~i! at 550 °C,T,700 °C it decreases toward an equilibrium level, ~ii! at 700 °C,T,800 °C it decreases during the first minutes and subsequently increases again, and ~iii! at temperatures ,550 °C or T.800 °C it increases continuously. In order to explain the carrier removal observed during annealing at 550–800 °C we proposed that metastable acceptor centers are formed during the B1 implantation and/or the initial period of the annealing time. Interaction of Si self-interstitial atoms with these centers leads to their neutralization and/or dissociation with consequent decreasing of the carrier concentration

Enhanced damage accumulation in carbon implanted silicon

The accumulation of damage in Si implanted with 12C+ was investigated experimentally using aligned Rutherford backscattering analysis. The damage protiles in Si implanted with 12C+ or 11B+ at 50 keV to the same doses and dose rate were compared. It was found that the damage accumulates at a noticeably higher rate by 12C+ implantation than by 11B+, especially for doses >2X 1Or5 cmm2. In order to explain our results we suggest that self-interstitial Si atoms are captured by the implanted C atoms, forming complex defects which are stable at room temperature

Electrical activation of carbon in GaAs : implantation temperature effects

Carbon was implanted into GaAs at the energy of 1 MeV with doses between 131013 and 2 31015 cm22 at temperatures of 80 K, nominal room temperature (RT), and 300 °C. A markedly higher electrical activation was obtained in the samples implanted at 80 K compared to those implanted at RT or 300 °C, attaining a maximum hole concentration of 231019 cm23. The redistribution of the C profile during rapid thermal annealing at temperatures from 700 to 950 °C for 10 s was found negligible, independently of the implantation temperature. Similar improvements in the electrical properties were also verified in samples implanted at 80 K with a lower energy of 60 keV. We consider that despite the light mass of C ions, the reduced dynamic annealing at 80 K allows the accumulation of an abundance of As vacancies, which assist the C activation as a p-type dopant

PIBID/diversidade nas escolas do campo: novas experiências na formação dos futuros educadores do campo

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014O trabalho foi desenvolvido numa parceria com cinco Escolas do Campo da região sudoeste do Paraná, nos municípios de Candói, Escola Estadual de Lagoa Seca, Colégio Estadual Bom Jesus, em Marmeleiro, Colégio Estadual Padre Réus, em Pérola d’Oeste, Colégio Estadual São Francisco do Bandeira, em Dois Vizinhos, Casa Familiar Rural de São Jorge d’Oeste. As atividades desenvolvidas nas escolas do campo tiveram como objetivo a melhoria das condições de formação dos acadêmicos do curso de Licenciatura em Educação do Campo com habilitação em Matemática e Ciências da Natureza e Ciências Agrárias, a interação entre a Universidade e as escolas do campo de ensino básico, formação de professores das Escolas do Campo. Foram divididas em dois eixos; formativo e profissional e foram realizadas através do desenvolvimento de atividades formativas nas Escolas do Campo nas respectivas áreas do curso através de seminários, feiras do conhecimento, gincanas, construção de fontes e equipamentos para utilização dos recursos naturais renováveis, vídeos com discussão e reflexã

Estudo da implantação de As a baixas energias em Si e SIMOX

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Kinetic of dry matter ruminal degradation of stem, root, aerial part hay and ureatreated-cassava root silage (Manihot esculenta Crantz)

O experimento foi conduzido na UESB, com o objetivo de se determinar a cinética da degradação ruminal da matéria seca, de alimentos obtidos da mandioca. Foram utilizadas duas vacas fistuladas no rúmen, incubando-se as amostras em sacolas de náilon por 2, 4, 8, 16, 24, 48, 72 e 96 horas, por quatro rodadas seqüenciais, dentro de um delineamento em blocos inteiramente cazualizados. Os alimentos testados foram a raiz (T1), a silagem de raízes tratada com 3% de uréia (T2), o feno da parte aérea da mandioca obtido aos 5 meses (T3) ou 14 meses após o plantio (T4) e as hastes de plantas de mandioca, colhidas aos 14 meses, plantadas em espaçamento contínuo (T5) ou de 0,6 metros entre plantas (T6). Os resultados dos percentuais de degradabilidade no rúmen (P), foram ajustados ao modelo matemático "P = a + b (1 - e-ct)". Os valores médios percentuais dos resultados encontrados foram comparados pelo teste de Student-Newman-Keuls, ao nível de 5% de probabilidade, como se segue para os tratamentos de 1 a 6, respectivamente: fração solúvel (74,8b; 80,9ª; 26,3c; 23,6d; 22,4d; 22,3d), degradabilidade efetiva (90,7b; 92,0ª; 65,4c; 62,4d; 41,8e; 40,9e), degradabilidade potencial (99,1ª; 99,4ª; 74,4b; 73,4b; 49,2c; 46,8d) e tempo de colonização em horas (0,4cb; 0,1c; 1,5ba; 1,5ba; 1,6ba; 1,8ª). Os resultados indicam uma alta taxa de solubilidade ruminal da silagem de raiz de mandioca tratada com uréia e uma maior taxa de degradabilidade efetiva do feno obtido aos 5 meses em relação ao obtido aos 14 meses após o plantio.This experiment was carried out at the Southwestern State University of Bahia (UESB), Bahia, Brazil, in order to verify the kinetic of dry matter ruminal degradation of cassava byproducts. Two cows, fistulated in the rumen, were used to incubate samples in nylon bags for 2, 4, 8, 16, 24, 48, 72 and 96 hours, in a completely randomized block design, resulting in four incubation periods for each sample. Tested feedstuffs were cassava root (T1), cassava root silage treated with 3% of urea (T2), cassava aereal part hay (CLH) harvested at 5 (T3) or 14 months of age (T4) and the stems of cassava plants, harvested at 14 months, planted in continuous rows (T5) or 0,6 meters between plants (T6) along the planting line. Percentual results of feed rumen degradabilities (P), were adjusted to the mathematical model "P = a + b (1 - e-ct)". Average percent results found in the treatments were compared using Student-Newman-Keuls test, at the level of 5% of probability. Results for treatments 1 to 6, were respectively: soluble fraction (74,8b; 80,9ª; 26,3c; 23,6d; 22,4d; 22,3d), effective degradability (90,7b; 92,0ª; 65,4c; 62,4d; 41,8e ; 40,9e), potential degradability (99,1ª; 99,4ª; 74,4b; 73,4b; 49,2c; 46,8d) and lag time in hours (0,4cb; 0,1c; 1,5ba; 1,5ba; 1,6ba; 1,8ª). These results indicate a high level of ruminal solubility of cassava root silage treated with urea and a higher degradation rate of CH harvested at 5 months compared to CH harvested at 14 months of age

LEVANTAMENTO FLORÍSTICO PRELIMINAR DA CAATINGA SUBLITORÂNEA NA PARAÍBA, NORDESTE DO BRASIL

Os estudos florísticos realizados no Agreste, área de transição entre os biomas Caatinga e Mata Atlântica, vêm sendo melhor discutidos recentemente. Entretanto são necessários novos estudos que envolvam uma maior amplitude das áreas limítrofes destes biomas, especialmente no que se refere às Florestas Estacionais Deciduais de Terras Baixas. Nesta concepção, o referente trabalho apresenta um levantamento florístico preliminar realizado no Agreste Sublitorâneo, bem como aponta as similaridades e diferenças entre esta formação e a Caatinga interiorana, a Mata Atlântica litorânea e o Agreste da Borborema. Foram registradas 231 espécies de Angiospermas, sendo Fabaceae, com 46 espécies, e Bignoniaceae, com 15 espécies, as famílias mais representativas na região. A estrutura florística do Agreste Sublitorâneo se assemelha as descritas em levantamentos realizados no Agreste da Borborema. Entretanto, diversas espécies amplamente distribuídas na Caatinga, que também ocorrem no Agreste da Borborema não ocorrem nas Florestas Estacionais Deciduais de Terras Baixas da Paraíba, sugerindo que a diferença de altitude entre a Depressão Sublitorânea e o Planalto da Borborema pode atuar como barreira de isolamento, impedindo que estas espécies se dispersem pela Caatinga Sublitorâne

Estado nutricional e programa bolsa família no semiárido mineiro: um estudo longitudinal/ Nutritional status and the bolsa família program in minas gerais : a longitudinal study

Introduction: The nutritional status during child growth is the measure that best defines the child's health, and further, it is an indicator of economic inequality. To improve the food and nutritional status, social programs, such as the Bolsa Família Program (BFP), have been enforced in Brazil with the objective of increasing the income of families with a low socioeconomic status.Objective: This study aimed to verify the association between enrollment in this program and the nutritional status of adolescents living in the city of Berilo who were evaluated in the preschool phase in 2004 and reassessed in 2016.Methods: The nutritional status was evaluated based on the height and body mass index according to the age. Statistical analysis was conducted using the Chi-square test of homogeneity, and the final model was analyzed using the logistic regression method. Results: There was an association between the access of the participants to the BFP and the socioeconomic condition of the household. On comparing the nutritional status of the children between 2004 and 2016, it was verified that the incidence of malnutrition decreased from 13.0% to 1.5% and that of being overweight increased from 5.1% to 17.8%; however, these changes were not associated with enrollment in the program.Conclusion: The nutritional status of the adolescents assessed improved between 2004 and 2016, regardless of enrollment in BFP.Introduction: The nutritional status during child growth is the measure that best defines the child's health, and further, it is an indicator of economic inequality. To improve the food and nutritional status, social programs, such as the Bolsa Família Program (BFP), have been enforced in Brazil with the objective of increasing the income of families with a low socioeconomic status. Objective: This study aimed to verify the association between enrollment in this program and the nutritional status of adolescents living in the city of Berilo who were evaluated in the preschool phase in 2004 and reassessed in 2016. Methods: The nutritional status was evaluated based on the height and body mass index according to the age. Statistical analysis was conducted using the Chi-square test of homogeneity, and the final model was analyzed using the logistic regression method. Results: There was an association between the access of the participants to the BFP and the socioeconomic condition of the household. On comparing the nutritional status of the children between 2004 and 2016, it was verified that the incidence of malnutrition decreased from 13.0% to 1.5% and that of being overweight increased from 5.1% to 17.8%; however, these changes were not associated with enrollment in the program. Conclusion: The nutritional status of the adolescents assessed improved between 2004 and 2016, regardless of enrollment in BFP

Contribuições de uma Liga de Anatomia Clínica e Cirúrgica durante a Pandemia: Relato de Experiência

Durante a pandemia do novo coronavírus, diversas restrições ao contato social foram implementadas no Brasil e no mundo. Sendo assim, o cotidiano foi forçadamente adaptado às novas necessidades de distanciamento. Dentro do mundo acadêmico, a atuação das ligas acadêmicas foi também acomodada ao contexto. Esse estudo, do tipo descritivo, transversal, retrospectivo de caráter qualitativo, relata as ações da Liga Acadêmica de Anatomia Clínica e Cirúrgica da Universidade Federal do Paraná – Campus Toledo na pandemia. As aulas ministradas pela Liga a cada quinze dias começaram a ser exibidas online, com boa parte sendo aberta ao público. A criação do projeto de extensão “Anatodúvidas”, com postagens informativas baseadas no conhecimento científico e direcionadas para o público geral ocorreu em 2021. A Primeira Jornada de Anatomia Clínica e Cirúrgica do Oeste do Paraná foi realizada de modo completamente virtual, com palestrantes vindos de todo o país nesse mesmo ano. Também foram publicados resumos em Congressos de Medicina. Dessa maneira, a liga agiu na pandemia sob os princípios da democratização do conhecimento, buscando divulgar informações de confiança, despertar o interesse na disciplina e complementando a formação médica