Atomic composition profile change of SiGe islands during Si capping

The 6% Ge isocomposition profile change of individual SiGe islands during Si capping at 640 degrees C is investigated by atomic force microscopy combined with a selective etching procedure. The island shape transforms from a dome to a {103}-faceted pyramid at a Si capping thickness of 0.32 nm, followed by the decreasing of pyramid facet inclination with increasing Si capping layer thickness. The 6% Ge isocomposition profiles show that the island with more highly Si enriched at its one base corner before Si capping becomes to be more highly Si intermixed along pyramid base diagonals during Si capping. This Si enrichment evolution inside an island during Si capping can be attributed to the exchange of capped Si atoms that aggregated to the island by surface diffusion with Ge atoms from inside the island by both atomic surface segregation and interdiffusion rather than to the atomic interdiffusion at the interface between the island and the Si substrate. In addition, the observed Si enrichment along the island base diagonals is attempted to be explained on the basis of the elastic constant anisotropy of the Si and Ge materials in (001) plane. (c) 2006 American Institute of Physics.

Religião, redes sociais e capital social no Município de Rio Grande da Serra na Região do Grande ABC Paulista. Estudo das trocas materiais e simbólicas em contexto de periferia urbana

O município de Rio Grande da Serra está situado em uma região Grande ABC paulista reconhecida nacionalmente por seu desenvolvimento econômico e industrial e pelas lutas políticas e sindicais. Paradoxalmente, se configura, social e territorialmente falando, por uma região de periferia urbana. Resultado da forma como a urbanização, na sociedade moderna, conforma o espaço em regiões centrais e periféricas. Localizado no caminho que ligava Santos à Mogi das Cruzes (século XIX) povoado de Geribatiba decorrente das transformações urbanas ocorridas em toda a região, conquistaria, nos anos 1960, sua autonomia político-administrativa. Nas décadas seguintes testemunhou intenso crescimento populacional, resultado do processo migratório, principalmente de mineiros e nordestinos que tinham as cidades, e indústrias, de São Paulo e Grande ABC como destino. Esse deslocamento de pessoas, e as redes formadas em seu em torno, contribuiu para o desenvolvimento de seu campo religioso. Atualmente, com uma população, em torno, de 46 mil habitantes, possui aproximadamente 180 locais de cerimônias religiosas. Nesse contexto, a tese analisa a inserção regional socioeconômica e religiosa de Rio Grande da Serra, a partir de dados comparativos com os demais municípios, e discute como o regionalismo tem contribuído para seu desenvolvimento econômico. Realiza a caracterização das periferias urbanas, discutindo aspectos que lhes são inerentes, como segregação e vulnerabilidade social. Nesse sentido, a investigação possibilitou a identificação do perfil socioeconômico (renda e escolaridade) dos participantes dos grupos religiosos (católicos, evangélicos, kardecistas e umbandistas), permitindo, também, identificar desigualdades sociais no interior de seu território, constatando que determinados bairros são mais vulneráveis do que outros. Considerando que esse estudo examina a capacidade das redes sociais e religiosas, de aumentar o capital social de seus participantes, foi realizado o mapeamento e etnografia das diversas práticas associativas, mais ou menos formais e estruturadas, de forma a analisar os elementos materiais e simbólicos por elas produzidos. Constatou-se, apoiado na aplicação de questionários, entrevistas e observação participativa, que, a partir do habitus religioso de cada grupo, as redes possibilitam no âmbito econômico questões como emprego e renda ou auxílio em necessidades básicas de sobrevivência, através de campanhas e trabalhos sociais. No âmbito simbólico, as redes propiciam questões importantes à existência humana, como a crença na salvação ou evolução da alma, socialização, autoestima, prestígio ou ainda a expectativa de cura ou tratamento de dependência química. Pôde-se aferir que, a despeito das diferentes formas como cada grupo, e seus participantes, se apropriam do capital social, as redes sociais e religiosas, no município, funcionam como redes de proteção, especialmente à população em situação alta de vulnerabilidade social.

Por falar em ausência... : as pessoas com deficiência

Esta dissertação propõe uma interface entre duas áreas de conhecimento, a educação e a teologia, a partir de um novo paradigma educacional: a inclusão. Tomamos a perspectiva das pessoas com deficiência e perguntamos pela contribuição da educação inclusiva para os discursos teológicos, bem como dos discursos teológicos para a inclusão social e educacional das pessoas com deficiência. A antropologia dará a nuance desta interface, posto que, historicamente, este tema esteve envolto em antropologias religiosas dicotômicas e excludentes. propomos, portanto, a superação dos paradigmas exclusivamente cartesianos que marcam a sociedade contemporânea, sociedade esta acostumada a classificar as pessoas, hierarquizando as suas diferenças. Nestes termos, a sociologia das ausências nos auxilia na compreensão dos mecanismos de segregação e exclusão das pessoas com deficiência (tanto na educação quanto na teologia) e aponta para a necessária valorização das experiências sociais das pessoas com deficiência - respeitando a diversidade e valorizando a diferença. O movimento se dá, portanto, no sentido da visibilidade das pessoas com deficiência nos discursos teológicos, bem como nos espaços eclesiais (dada à dimensão dialética desta rela-ção). Entendemos que este é um movimento inadiável, já iniciado por alguns teólogos, quando os mesmos falam do necessário reconhecimento recíproco, da digna vulnerabilidade humana e do desafio ético que a inclusão nos coloca no sentido do reconhecimento da interdependência e da necessária operacionalização da solidariedade nos espaços sociais (acessibilidade). Todavia, estas categorias são como frestas entreabertas na porta teológica, pois, em sua maioria, nem os discursos teológicos e nem os espaços eclesiais ainda não dão visibilidade às pessoas com deficiência.

Isaías 24,1-6 na perspectiva da profecia apocalipsista resultante de um complexo processo sócio-teológico em transição

A dissertação objetiva estudar o papel que o apocalipsismo, desempenhou na história e no contexto da redação do oráculo isaiano em Isaías 24,1-6. A proposta é de que sua função foi de grande importância no processo de formação do judaísmo pós-exílico, fomentando uma nova reidentificação e reetnização dos israelitas-judaítas num contexto de frustração nacionalista e religiosa que gerou uma grande heterogeneidade teológica. Identificamos este contexto como sendo o ambiente em que se deu um complexo processo de transição sócio-teológica na história dos judaitas no período de dominação persa. O apocalipsismo, enquanto fenômeno religioso e sócio-histórico, se mostrou como resultado de uma realidade hostil e desumanizadora na qual a identidade teológico-cultural e os relacionamentos sócioeconômicos das pessoas foram extremamente ameaçados e violentados gerando uma contraposição aos desígnios de Yahweh expressos na aliança firmada por ele para com seu povo. Através da pesquisa e análise exegética de Isaías 24,1-6, a presente dissertação propõe que, a partir dessa realidade conflituosa, a profecia apocalipsista isaiana se manifesta contra as estruturas e suas articulações geradoras de segregação e desumanidade, lançando uma esperança no ato transformador por intermédio de Yahweh, o senhor da história, que possibilita um reverso histórico, a partir do qual será possível reconstruir relacionamentos favoráveis no âmbito social e espiritual.(AU)

Ion bombardment induced compositional changes in compound semiconductor surfaces studied by XPS combined with LEISS

Surface compositional change of GaP, GaAs, GaSb, InP, InAs, InSb, GeSi and CdSe single crystals due to low keV noble gas ion beam bombardment has been investigated by combining X-ray Photoelectron Spectroscopy (XPS) and Low Energy Ion Scattering Spectroscopy (LEISS). The purpose of using this complementary analytical method is to obtain more complete experimental evidence of ion beam modification in surfaces of compound semiconductors and GeSi alloy to improve the understanding of the mechanisms responsible for these effects. Before ion bombardment the sample surfaces were analysed nondestructively by Angular Resolved XPS (ARXPS) and LEISS to get the initial distribution of surface composition. Ion bombardment experiments were carried out using 3keV argon ions with beam current of 1μA for a period of 50 minutes, compositional changes in the surfaces of compound semiconductors and GeSi alloy were monitored with normal XPS. After ion bombardment the surfaces were re-examined with ARXPS and LEISS. Both XPS and LEISS results showed clearly that ion bombardment will change the compositional distribution in the compound semiconductor and GeSi surfaces. In order to explain the observed experimental results, two major theories in this field, Sigmund linear collision cascade theory and the thermodynamic models based on bombardment induced Gibbsian surface segregation and diffusion, were investigated. Computer simulation using TRIM code was also carried out for assistance to the theoretical analysis. Combined the results obtained from XPS and LEISS analyses, ion bombardment induced compositional changes in compound semiconductor and GeSi surfaces are explained in terms of the bombardment induced Gibbsian surface segregation and diffusion.

NOx storage-reduction characteristics of Ba-based lean NOx trap catalysts subjected to simulated road aging

In order to study the effect of washcoat composition on lean NOx trap (LNT) aging characteristics, fully formulated monolithic LNT catalysts containing varying amounts of La-stabilized CeO2 (5 wt% La2O3) or CeO2-ZrO2 (Ce:Zr = 70:30) were subjected to accelerated aging on a bench reactor. Subsequent catalyst evaluation revealed that aging resulted in deterioration of the NOx storage, NOx release and NOx reduction functions, whereas the observation of lean phase NO2 slip for all of the aged catalysts indicated that LNT performance was not limited by the kinetics of NO oxidation. After aging, all of the catalysts showed increased selectivity to NH3 in the temperature range 250–450 °C. TEM, H2 chemisorption, XPS and elemental analysis data revealed two main changes which can explain the degradation in LNT performance. First, residual sulfur in the catalysts, present as BaSO4, decreased catalyst NOx storage capacity. Second, sintering of the precious metals in the washcoat was observed, which can be expected to decrease the rate of NOx reduction. Additionally, sintering is hypothesized to result in segregation of the precious metal and Ba phases, resulting in less efficient NOx spillover from Pt to Ba during NOx adsorption, as well as decreased rates of reductant spillover from Pt to Ba and reverse NOx spillover during catalyst regeneration. Spectacular improvement in LNT durability was observed for catalysts containing CeO2 or CeO2-ZrO2 relative to their non-ceria containing analog. This was attributed to (i) the ability of ceria to participate in NOx storage/reduction as a supplement to the main Ba NOx storage component; (ii) the fact that Pt and CeO2(-ZrO2) are not subject to phase segregation; and (iii) the ability of ceria to trap sulfur, resulting in decreased sulfur accumulation on the Ba component.

Origin of the Grande Ronde Formation flows, Columbia River flood basalt group

Lavas belonging to the Grande Ronde Formation (GRB) constitute about 63% of the Columbia River Basalt Group (CRBG), a flood basalt province in the NW United States. A puzzling feature is the lack of phenocrysts (< 5%) in these chemically evolved lavas. Based mainly on this observation it has been hypothesized that GRB lavas were nearly primary melts generated by large-scale melting of eclogite. Another recent hypothesis holds that GRB magmas were extremely hydrous and rose rapidly from the mantle such that the dissolved water kept the magmas close to their liquidi. I present new textural and chemical evidence to show that GRB lavas were neither primary nor hydrous melts but were derived from other melts via efficient fractional crystallization and mixing in shallow intrusive systems. Texture and chemical features further suggest that the melt mixing process may have been exothermic, which forced variable melting of some of the existing phenocrysts. ^ Finally, reported here are the results of efforts to simulate the higher pressure histories of GRB using COMAGMAT and MELTS softwares. The intent was to evaluate (1) whether such melts could be derived from primary melts formed by partial melting of a peridotite source as an alternative to the eclogite model, or if bulk melting of eclogite is required; and (2) at what pressure such primary melts could have been in equilibrium with the mantle. I carried out both forward and inverse modeling. The best fit forward model indicates that most primitive parent melts related to GRB could have been multiply saturated at ∼1.5--2.0 GPa. I interpret this result to indicate that the parental melts last equilibrated with a peridotitic mantle at 1.5--2.0 GPa and such partial melts rose to ∼0.2 GPa where they underwent efficient mixing and fractionation before erupting. These models suggest that the source rock was not eclogitic but a fertile spinel lherzolite, and that the melts had ∼0.5% water. ^

Temporal Population Genetic Structure of Eastern Mosquitofish in a Dynamic Aquatic Landscape

We analyzed the effect of periodic drying in the Florida Everglades on spatiotemporal population genetic structure of eastern mosquitofish (Gambusia holbrooki). Severe periodic drying events force individuals from disparate sources to mix in dry season relatively deep-water refuges. In 1996 (a wet year) and 1999 (a dry year), we sampled mosquitofish at 20 dry-season refuges distributed in 3 water management regions and characterized genetic variation for 10 allozyme and 3 microsatellite loci. In 1996, most of the ecosystem did not dry, whereas in 1999, many of our sampling locations were isolated by expanses of dried marsh surface. In 1996, most spatial genetic variation was attributed to heterogeneity within regions. In 1999, spatial genetic variation within regions was not significant. In both years, a small but significant amount of variation (less than 1% of the total variation) was partitioned among regions. Variance was consistently greater than zero among long-hydroperiod sites within a region, but not among short-hydroperiod sites within a region, where hydroperiod was measured as time since last marsh surface dry-down forcing fishes into local refuges. In 1996, all sites were in Hardy–Weinberg equilibrium. In 1999, we observed fewer heterozygotes than expected for most loci and sites suggesting a Wahlund effect arising from fish leaving areas that dried and mixing in deep-water refuges.

Sedimentology of cores from the Iberian margin

Bioturbation in marine sediments has basically two aspects of interest for palaeo-environmental studies. First, the traces left by the burrowing organisms reflect the prevailing environmental conditions at the seafloor and thus can be used to reconstruct the ecologic and palaeoceanographic situation. Traces have the advantage over other proxies of practically always being preserved in situ. Secondly, for high- resolution stratigraphy, bioturbation is a nuisance due to the stirring and mixing processes that destroy the stratigraphic record. In order to evaluate the applicability of biogenic traces as palaeoenvironmental indicators, a number of gravity cores from the Portuguese continental slope, covering the period from the last glacial to the present were investigated through X-ray radiographs. In addition, physical and chemical parameters were determined to define the environmental niche in each core interval. A number of traces could be recognized, the most important being: Thalassinoides, Planolites, Zoophycos, Chondrites, Scolicia, Palaeophycus, Phycosiphon and the generally pyritized traces Trichichnus and Mycellia. The shifts between the different ichnofabrics agree strikingly well with the variations in ocean circulation caused by the changing climate. On the upper and middle slope, variations in current intensity and oxygenation of the Mediterranean Outflow Water were responsible for shifts in the ichnofabric. Larger traces such as Planolites and Thalassinoides dominated in coarse, well oxygenated intervals, while small traces such as Chondrites and Trichichnus dominated in fine grained, poorly oxygenated intervals. In contrast, on the lower slope where calm steady sedimentation conditions prevail, changes in sedimentation rate and nutrient flux have controlled variations in the distribution of larger traces such as Planolites, Thalassinoides, and Palaeophycus. Additionally, distinct layers of abundant Chondrites correspond to Heinrich events 1, 2, and 4, and are interpreted as a response to incursions of nutrient rich, oxygen depleted Antarctic waters during phases of reduced thermohaline circulation. The results clearly show that not one single factor but a combination of several factors is necessary to explain the changes in ichnofabric. Furthermore, large variations in the extent and type of bioturbation and tiering between different settings clearly show that a more detailed knowledge of the factors governing bioturbation is necessary if we shall fully comprehend how proxy records are disturbed. A first attempt to automatize a part of the recognition and quantification of the ichnofabric was performed using the DIAna image analysis program on digitized X-ray radiographs. The results show that enhanced abundance of pyritized microburrows appears to be coupled to organic rich sediments deposited under dysoxic conditions. Coarse grained sediments inhibit the formation of pyritized burrows. However, the smallest changes in program settings controlling the grey scale threshold and the sensitivity resulted in large shifts in the number of detected burrows. Therefore, this method can only be considered to be semi-quantitative. Through AMS-^C dating of sample pairs from the Zoophycos spreiten and the surrounding host sediment, age reversals of up to 3,320 years could be demonstrated for the first time. The spreiten material is always several thousands of years younger than the surrounding host sediment. Together with detailed X-ray radiograph studies this shows that the trace maker collects the material on the seafloor, and then transports it downwards up to more than one meter in to the underlying sediment where it is deposited in distinct structures termed spreiten. This clearly shows that age reversals of several thousands of years can be expected whenever Zoophycos is unknowingly sampled. These results also render the hitherto proposed ethological models proposed for Zoophycos as largely implausible. Therefore, a combination of detritus feeding, short time caching, and hibernation possibly combined also with gardening, is suggested here as an explanation for this complicated burrow.

A educação básica na região metropolitana de Natal: uma análise da qualidade educativa e sua relação com o contexto familiar dos alunos

This dissertation aimed to investigate the formal learning process of children and teenagers through elementary education and, mainly, the support of family on domestic school activities as a step in the teaching-learning process. The student's family, with its cultural capital, provides an assistance which was the bias of the essay analyzes presented on this paper, using a spatial area of public elementary schools of the municipalities of the Natal metropolitan region. Such frame of Natal metropolis has been justified by the recent review of their basic education, taken by the Brazilian Ministry of Education, diagnosed in 2011, only 1% of students were in a adequate mathematics learning stage. While 62% were considered in a critical stage in this discipline. Given this issue, this dissertation offers a theoretical analysis about inherited and acquired within the family cultural capital, mainly focusing in the distances between the cultural level of the student's family and the defendant by the school. Then, presents the fundamental aspects of the issue on the urban phenomenon, focusing on social hierarchies and structures of city spaces that express differentiation, segmentation and socio-spatial segregation, and social exclusion. The emphasis on inequalities points to the development of an urban ethos, through formal schooling, which develops from social singularities. To theoretically develop the theme of Cultural Capital Family, this study sought to operationalize the concept through the interpretation of the phenomenon studied by a logical validation work hypotheses. The operation concepts systemically transformed into statistical indicators in order to measure the impact of individual, social and cultural characteristics of students elements. Finally, this dissertation found that the components evaluated, family cultural capital and housing conditions, can influence the development of skills and competencies of students in the educational sphere

A inserção da família no processo socioeducativo de adolescentes em privação de liberdade

This master thesis has the main goal investigate how families are inserted in the socioeducational process of teenagers who are undergoing social measures of liberty deprivation. The specific objectives are: to characterize the family´s living together of adolescents deprived of their freedom and their families, from the actions and routines of the socio-educational system; to assess the professional working links in the context of socio-education, in order to care and strengthening families of the adolescents; to investigate how families evaluate the operation of socio-educational process in which adolescents are met. Method: to achieve the proposed objectives, data collection occurred in complementary steps: the first phase took place from visits to socioeducational units of liberty deprivation of RN, and dialogues with professionals working in socio-education. Subsequently, action research stage was carried out, from the insertion of the researcher in the extension project Family and the struggle for the effectiveness of the National Socio Service System, that aimed to strengthen monitoring the adolescents socio-education by their families, and had as methodology the conversation circles and thematic workshops. Lastly, were performed reading and analysis of the references to the family in the Individual Care Plans (PIAs) for adolescents. The information gathered was recorded in field diaries and subjected to thematic content analysis. This research was guided by the Marxist theoretical framework, structured on the understanding of the involvement of adolescents with illegal acts as a development and expression of the social question. From this theoretical framework, the prevailing view in the capitalist society of adolescents in conflict with the law as individuals who are treated by means of repression and segregation and the weakness of social policies is questioned, both in the execution of their own socioeducational measures as the articulation of network services for adolescent protection and strengthening your family. Results: in relation to the operation of the socioeducational system in RN in general, it was observed a state of unhealthy physical spaces and institutional practices that violate human rights, idleness and lack of access to social rights, and criminalization and institutionalization of poor young people and their families. With regard to family´s living together, it was noticed great distance between principles and guidelines recommended by the SINASE, about acquaintanceship and family strengthening, and every day practices of socio-education in RN: serious violations were observed that undermine the family´s living together, as the distance between the socio-educational units of deprivation of liberty and the cities where families live; absence, irregularity and poor conditions in carrying out the family visits; lack of conjugal visits; restricted and unarticulated actions for the care and strengthening of the families of adolescents, most of whom live in poverty or extreme poverty. Finally, it was found a number of blamefully and punishments to the family, including practices such as inward inspection (visual inspection while naked and squant), plus a series of violence and omissions care that sick family members and weaken the links between adolescents and their families.

Estudo da influência da adição de níquel em alumina pela rota da metalurgia do pó

Ceramic materials alumina basis have been widely used in structural components, mainly because owning properties such as high hardness, chemical inertness and good wear resistance, however, the low toughness is a factor that compromises its use in many other applications, featuring the addition of nickel as a possible solution to this problem, in this context, this work aims to study the addition of nickel alumina using the route of powder metallurgy processing of the material. The percentage of nickel were added 2, 4 and 6 wt%; and each composition to high energy milling in a planetary mill was performed for 2, 4, 9 and 16h. Subsequently, the samples were compacted at 300 MPa and sintered in a vacuum oven at 1400⁰C for 2h. The samples were characterized as the physical and mechanical properties, observing, in general, an improvement in sinterability of the material with increasing grinding time and nickel content, and mixing with a decrease of porosity and increase of hardness, density values above 80% of theoretical were obtained. The milling time of 4 hours and addition of 2% nickel, particularly if achieved higher hardness (HV 1068.7 +/- 32.6) and density of about 99% theoretical density.

Estudo da influência da adição de níquel em alumina pela rota da metalurgia do pó

Ceramic materials alumina basis have been widely used in structural components, mainly because owning properties such as high hardness, chemical inertness and good wear resistance, however, the low toughness is a factor that compromises its use in many other applications, featuring the addition of nickel as a possible solution to this problem, in this context, this work aims to study the addition of nickel alumina using the route of powder metallurgy processing of the material. The percentage of nickel were added 2, 4 and 6 wt%; and each composition to high energy milling in a planetary mill was performed for 2, 4, 9 and 16h. Subsequently, the samples were compacted at 300 MPa and sintered in a vacuum oven at 1400⁰C for 2h. The samples were characterized as the physical and mechanical properties, observing, in general, an improvement in sinterability of the material with increasing grinding time and nickel content, and mixing with a decrease of porosity and increase of hardness, density values above 80% of theoretical were obtained. The milling time of 4 hours and addition of 2% nickel, particularly if achieved higher hardness (HV 1068.7 +/- 32.6) and density of about 99% theoretical density.