A clinical follow-up study of the periodontal conditions of RPD abutment and non-abutment teeth

The purpose of this study was to evaluate the periodontal conditions of removable partial denture (RPD) wearers, comparing direct and indirect abutment teeth, and the teeth not involved in the denture design before denture placement and 1 year later. Fifty patients (32 women and 18 men), average age 45, were assessed by the same examiner at the moment of denture insertion and 3, 6, 9 and 12 months later. The following items were verified in each assessment: probing depth (PD), plaque index (PI) and gingival index (GI). PD and PI data were evaluated by ANOVA test for linear trend followed by Tukey-Kramer post-test, while GI data were analysed by Friedman's test. Results showed that the teeth not involved in the denture design were the least affected for all variables studied. It was also verified that PD and GI mean values increased from the initial assessment to 1 year of RPD wearing in every group, but that only PI showed a significant increase. This study indicated that direct and indirect retainer elements tend to undergo more damaging periodontal effects associated with RPD wearing when compared with non-abutment elements. Plaque index values were significantly higher after 1 year of denture use.

Non-agricultural rural employment in Central America

Includes bibliography

Computational studies on the structure and stabilities of magnetic inter-metallic compounds

The purpose of this thesis is to further the understanding of the structural, electronic and magnetic properties of ternary inter-metallic compounds using density functional theory (DFT). Four main problems are addressed. First, a detailed analysis on the ternary Heusler compounds is made. It has long been known that many Heusler compounds ($X_2YZ$; $X$ and $Y$ transition elements, $Z$ main group element) exhibit interesting half-metallic and ferromagnetic properties. In order to understand these, the dependence of magnetic and electronic properties on the structural parameters, the type of exchange-correlation functional and electron-electron correlation was examined. It was found that almost all Co$_2YZ$ Heusler compounds exhibit half-metallic ferromagnetism. It is also observed that $X$ and $Y$ atoms mainly contribute to the total magnetic moment. The magnitude of the total magnetic moment is determined only indirectly by the nature of $Z$ atoms, and shows a trend consistent with Slater-Pauling behaviour in several classes of these compounds. In contrast to experiments, calculations give a non-integer value of the magnetic moment in certain Co$_2$-based Heusler compounds. To explain deviations of the calculated magnetic moment, the LDA+$U$ scheme was applied and it was found that the inclusion of electron-electron correlation beyond the LSDA and GGA is necessary to obtain theoretical description of some Heusler compounds that are half-metallic ferromagnets. The electronic structure and magnetic properties of substitutional series of the quaternary Heusler compound Co$_2$Mn$_{1-x}$Fe$_x$Si were investigated under LDA+$U$. The calculated band structure suggest that the most stable compound in a half-metallic state will occur at an intermediate Fe concentration. These calculated findings are qualitatively confirmed by experimental studies. Second, the effect of antisite disordering in the Co$_2$TiSn system was investigated theoretically as well as experimentally. Preservation of half-metallicity for Co$_2$TiSn was observed with moderate antisite disordering and experimental findings suggest that the Co and Ti antisites disorder amounts to approximately 10~% in the compound. Third, a systematic examination was carried out for band gaps and the nature (covalent or ionic) of bonding in semiconducting 8- and 18-electron or half-metallic ferromagnet half-Heusler compounds. It was found that the most appropriate description of these compounds from the viewpoint of electronic structures is one of a $YZ$ zinc blende lattice stuffed by the $X$ ion. Simple valence rules are obeyed for bonding in the 8- and 18-electron compounds. Fourth, hexagonal analogues of half-Heusler compounds have been searched. Three series of compounds were investigated: GdPdSb, GdAutextit{X} (textit{X} = Mn, Cd and In) and EuNiP. GdPdSb is suggested as a possible half-metallic weak ferromagnet at low temperature. GdAutextit{X} (textit{X} = Mn, Cd and In) and EuNiP were investigated because they exhibit interesting bonding, structural and magnetic properties. The results qualitatively confirm experimental studies on magnetic and structural behaviour in GdPdSb, GdAutextit{X} (textit{X} = Mn, Cd and In) and EuNiP compounds. ~

Analyses of ferromanganese micronodules from the central Arctic Ocean

In order to determine geochemical compositions of Late Cenozoic Arctic seawater, oxide fractions were chemically separated from 15 samples of hand-picked ferromanganese micronodules (50-300 mu m). The success of the chemical separation is indicated by the fact that >97% of the Sr in the oxide fraction is seawater-derived. Rare-earth element (REE) abundances of the Arctic micronodule oxide fractions are much lower than those of bulk Fe-Mn nodules from other ocean basins of the world (e.g., 33 vs. 145 ppm Nd), but the Arctic oxides are enriched in Ce relative to Nd (Ce-N/Nd-N=2.2+/-0.5) and have convex-upward, shale-normalized REE patterns (Nd-N/Gd-N=0.61+/-0.06, Gd-N/Yb-N = 1.5+/-0.2, Nd-N/Yb-N = 0.9+/-0.2), typical of other hydrogenous and diagenetic marine Fe-Mn-oxides. Bulk sediment samples from the central Arctic Ocean have REE abundances and patterns that are characteristic of those of post-Archean shale. Non-detrital fractions (calcite + oxide coatings) of Recent Arctic foraminifera have REE abundances and patterns similar to those of Recent foraminifera from the Atlantic Ocean. Electron microprobe analyses (n=178) of transition elements in 29 Arctic Fe-Mn micronodules from five different stratigraphic intervals of Late Cenozoic sediment indicate that oxide accretion occurred as a result of hydrogenetic and diagenetic processes close to the sediment-seawater interface. Transition element ratios suggest that no oxide accretion occurred during transitions from oxic to suboxic diagenetic conditions. Only K is correlated with Si and Al, and ratios of these elements suggest that they are associated with illite or phillipsite. Ca and Mg are correlated with Mn, which indicates variable substitution of these elements from seawater into the manganate phase. The geochemical characteristics of Arctic Fe-Mn micronodules indicate that the REEs of the oxide fractions were ultimately derived from seawater. However, because of minute contributions of Sr from siliciclastic detritus during diagenesis or during the chemical leaching procedure, Sr isotope compositions of the oxide fractions cannot be used to trace temporal changes in the Sr-87/Sr-86 ratio of Arctic seawater or to improve the chronostratigraphy.

The incorporation of construction and demolition wastes as recycled mixed aggregates in non-structural concrete precast pieces

Concern for the environment has lately heightened awareness about the need for recycling in the construction industry. However, some standards, such as the Spanish standard, only accept the recycling of aggregates derived from concrete, which limits the extensive use of construction and demolition waste, which are produced in much bigger volumes. The aim of this work was to explore the possibility of using recycled mixed aggregates (RMA) in the preparation of precast non-structural concretes. To that end different percentages of natural aggregate were replaced by RMA in non-structural elements (25, 50, 75 and 100%). Contents of cement, water, and the dosages commonly used by companies were unchanged by the introduction of RMA. The characterization of the prepared elements has been done using the specific tests for each type of non-structural element (terrazzo for indoor use, hollow tiles, kerbstones and paving blocks): compression and flexural strength, water absorption, dimensional tolerances, abrasion and slipping resistance. The paving blocks, kerbstones, and hollow tiles prepared were tested for 360 days. The stability of the tested properties confirmed the possibility of using these wastes on an industrial scale satisfying the standard requirements. However, the surface of terrazzo with RMA is not as good as that prepared with natural aggregate.

Statistical mechanics of low-density parity check error-correcting codes over Galois fields

A variation of low-density parity check (LDPC) error-correcting codes defined over Galois fields (GF(q)) is investigated using statistical physics. A code of this type is characterised by a sparse random parity check matrix composed of C non-zero elements per column. We examine the dependence of the code performance on the value of q, for finite and infinite C values, both in terms of the thermodynamical transition point and the practical decoding phase characterised by the existence of a unique (ferromagnetic) solution. We find different q-dependence in the cases of C = 2 and C ≥ 3; the analytical solutions are in agreement with simulation results, providing a quantitative measure to the improvement in performance obtained using non-binary alphabets.

Mechanical properties of concrete produced with a composite of water treatment sludge and sawdust

In developing countries such as Brazil, the wastes generated in the decanters and filters of water treatment plants are discharged directly into the same rivers and streams that supply water for treatment. Another environmental problem is the unregulated discard of wood wastes. The lumber and wood products industry generates large quantities of this waste, from logging to the manufacture of the end product. Brazil has few biomass plants and therefore only a minor part of these wastes are reused. This paper presents the results of the first study involving a novel scientific and technological approach to evaluate the possibility of combining these two types of wastes in the production of a light-weight composite for concrete. The concrete produced with cement:sand:composite:water mass ratios of 1:2.5:0.67:0.6 displayed an axial compressive strength of 11.1 MPa, a compressive and diametral tensile strength of 1.2 MPa, water absorption of 8.8%, and a specific mass of 1.847 kg/m(3). The mechanical properties obtained with this concrete render it suitable for application in non-structural elements. (C) 2010 Elsevier Ltd. All rights reserved.

O mar não está para peixe : uma etnografia dos conflitos socioambientais em torno da Zona de Proteção Marinha e da comunidade pesqueira do Bugigão – RESEXMAR do Corumbau/Bahia.

A Reserva Extrativista Marinha (RESEXMAR) do Corumbau foi criada no ano de 2000, a partir de uma ação coletiva, iniciada em 1997 por meio das lideranças de pescadores locais, na busca de instrumento jurídico que garantisse o acesso exclusivo dos recursos pesqueiros contra a atividade da pesca comercial de camarão sete-barbas que se instalou na década de 1980. Durante o processo de criação da RESEXMAR do Corumbau, os pescadores obtiveram apoio de órgãos governamentais, como a Coordenação Nacional de Populações Tradicionais (CNPT) e de entidades ambientalistas do terceiro setor – Associação Pradense de Proteção Ambiental (APPA), e posteriormente a Conservation International do Brasil (CI-Brasil). Entretanto, após a criação da RESEXMAR do Corumbau – entre os anos 2000 e 2002 – foi elaborado o Plano de Manejo que orientaria a gestão da Unidade de Conservação (UC). O documento foi capitaneado pela equipe técnica e científica vinculada à CI-Brasil, tendo como ponto de destaque a criação de áreas de exclusão total da atividade da pesca, por meio da Zona de Proteção Marinha (ZPM). A ideia de uma ZPM, para a CI-Brasil, era que de forma indireta e em médio e longo prazo, os pescadores se beneficiariam com o possível aumento de produção de pescado, contanto que 30% de cobertura de recifes tivesse algum tipo de proteção dos processos ecológicos, tais como reprodução e crescimento de espécies. Durante as discussões do Plano de Manejo e atualmente uma parcela de pescadores locais contestaram os limites da ZPM, pois iria restringir o acesso aos recursos pesqueiros. No entanto, tal contestação foi suprimida pelas relações não formais que os membros da CI-Brasil possuíam com o núcleo familiar principal da Vila do Corumbau, forçando os demais em um acordo formal temporário. Tal questionamento evidenciou um conflito de conjunto de normas distintas entre pescadores artesanais em relação à CI-Brasil e IBAMA: a pesca artesanal ‒ um tipo de ação que segue normas específicas das quais elementos humanos e não humanos interagem conjuntamente, evidenciando um conhecimento prático e corporizado constituindo um modelo compreensivo de mundo e de natureza; conceitos modernos e globalizantes de uma natureza totalmente desvinculada das práticas locais artesanais, com forte articulação de uma entidade ambientalista de alcance internacional, guiada pela emergência das questões ambientais, imprimindo no local (o lugar da prática da pesca tradicional) a ideia de um espaço (Áreas Marinhas Protegidas), desencaixado de formas específicas de natureza/culturas.

Mo and W bis-MGD enzymes: nitrate reductases and formate dehydrogenases

J Biol Inorg Chem (2004) 9: 791–799 DOI 10.1007/s00775-004-0573-9

Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited usinga pure Ta target and a working atmosphere with a constant N2/O2ratio. The choice of this constant ratiolimits the study concerning the influence of each reactive gas, but allows a deeper understanding of theaspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous.This work begins by analysing the data obtained directly from the film deposition stage, followed bythe analysis of the morphology, composition and structure. For a better understanding regarding theinfluence of the deposition parameters, the analyses are presented by using the following criterion: thefilms were divided into two sets, one of them produced with grounded substrate holder and the otherwith a polarization of −50 V. Each one of these sets was produced with different partial pressure of thereactive gases P(N2+ O2). All the films exhibited a O/N ratio higher than the N/O ratio in the depositionchamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increaseof the O content is observed, associated to the strong decrease of the N content, when P(N2+ O2) is higherthan 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazingincidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-rayreflectivity studies found out that the density of the films depended on the deposition conditions: thehigher the gas pressure, the lower the density. Firstly, a dominant -Ta structure is observed, for lowP(N2+ O2); secondly a fcc-Ta(N,O) structure, for intermediate P(N2+ O2); thirdly, the films are amorphousfor the highest partial pressures. The comparison of the characteristics of both sets of produced TaNxOyfilms are explained, with detail, in the text.

Recrystallisation rims in zircon (Valle d'Arbedo, Switzerland): an integrated cathodoluminescence, LA-ICP-MS, SHRIMP, and TEM study

Recrystallization rims are a common feature of zircon crystals that underwent metamorphism. We present a microstructural and microchemical study of partially recrystallized zircon grains collected in polymetamorphic migmatites (Valle d'Arbedo, Ticino, Switzerland). The rims are bright in cathodo-luminescence (CL), with sharp and convex contacts characterized by inward-penetrating embayments transgressing igneous zircon cores. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data and transmission electron microscopy (TEM) imaging indicate that the rims are chemically and microstructurally different from the cores. The rims are strongly depleted in REE, with concentrations up to two orders of magnitude lower than in the cores, indicating a significant loss of REE during zircon recrystallization. Enrichment in non-formula elements, such as Ca, has not been observed in the rims. The microstructure of zircon cores shows a dappled intensity at and below the 100 nm scale, possibly due to radiation damage. Other defects such as pores and dislocations are absent in the core except at healed cracks. Zircon rims are mostly dapple-free, but contain nanoscale pores and strain centers, interpreted as fluid inclusions and chemical residues, respectively. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb ages show that the recrystallization of the rims took place >200 Ma ago when the parent igneous zircon was not metamict. The chemical composition and the low-Ti content of the rims indicate that they form at sub-solidus temperatures (550-650 degrees C). Recrystallization rims in Valle d'Arbedo zircon are interpreted as the result of the migration of chemical reaction fronts in which fluid triggered in situ and contemporaneous interface-coupled dissolution-reprecipitation mechanisms. This study indicates that strong lattice strain resulting from the incorporation of a large amount of impurities and structural defects is not a necessary condition for zircon to recrystallize. Our observations suggest that the early formation of recrystallization rims played a major role in preserving zircon from the more recent Alpine metamorphic overprint.

An improved trap design for decoupling multinuclear RF coils.

PURPOSE: Multinuclear magnetic resonance spectroscopy and imaging require a radiofrequency probe capable of transmitting and receiving at the proton and non-proton frequencies. To minimize coupling between probe elements tuned to different frequencies, LC (inductor-capacitor) traps blocking current at the (1) H frequency can be inserted in non-proton elements. This work compares LC traps with LCC traps, a modified design incorporating an additional capacitor, enabling control of the trap reactance at the low frequency while maintaining (1) H blocking. METHODS: Losses introduced by both types of trap were analysed using circuit models. Radiofrequency coils incorporating a series of LC and LCC traps were then built and evaluated at the bench. LCC trap performance was then confirmed using (1) H and (13) C measurements in a 7T human scanner. RESULTS: LC and LCC traps both effectively block interaction between non-proton and proton coils at the proton frequency. LCC traps were found to introduce a sensitivity reduction of 5±2%, which was less than half of that caused by LC traps. CONCLUSION: Sensitivity of non-proton coils is critical. The improved trap design, incorporating one extra capacitor, significantly reduces losses introduced by the trap in the non-proton coil. Magn Reson Med 72:584-590, 2014. © 2013 Wiley Periodicals, Inc.

EGASP: the human ENCODE Genome Annotation Assessment Project

Background: Non-long terminal repeat (non-LTR) retrotransposons have contributed to shaping the structure and function of genomes. In silico and experimental approaches have been used to identify the non-LTR elements of the urochordate Ciona intestinalis. Knowledge of the types and abundance of non-LTR elements in urochordates is a key step in understanding their contribution to the structure and function of vertebrate genomes. Results: Consensus elements phylogenetically related to the I, LINE1, LINE2, LOA and R2 elements of the 14 eukaryotic non-LTR clades are described from C. intestinalis. The ascidian elements showed conservation of both the reverse transcriptase coding sequence and the overall structural organization seen in each clade. The apurinic/apyrimidinic endonuclease and nucleic-acid-binding domains encoded upstream of the reverse transcriptase, and the RNase H and the restriction enzyme-like endonuclease motifs encoded downstream of the reverse transcriptase were identified in the corresponding Ciona families. Conclusions: The genome of C. intestinalis harbors representatives of at least five clades of non-LTR retrotransposons. The copy number per haploid genome of each element is low, less than 100, far below the values reported for vertebrate counterparts but within the range for protostomes. Genomic and sequence analysis shows that the ascidian non-LTR elements are unmethylated and flanked by genomic segments with a gene density lower than average for the genome. The analysis provides valuable data for understanding the evolution of early chordate genomes and enlarges the view on the distribution of the non-LTR retrotransposons in eukaryotes.