Cascade multitemporal classification based on fuzzy Markov chains

This paper proposes a new fuzzy cascade multitemporal classification method based on Fuzzy Markov Chains. This method differs from prior fuzzy multitemporal approaches proposed thus far, as the method does not require the knowledge of the true class at an earlier date; instead it uses the attributes of the image object being classified at the earlier date. This method combines the fuzzy, non-temporal, classification of a geographical region at two points in time to provide a single unified result. A transformation law based on class transition possibilities projects the earlier classification onto the later date before combining both results. Performance analysis was conducted upon a sequence of three LANDSAT images from the central region of Brazil using a Genetic Algorithm to estimate transition possibilities. The analysis showed that the increase in performance is highly dependent on whether or not a significant correlation exists between the temporal data sets, as well as on the accuracy of the monotemporal classifier at the earlier date. While the monotemporal approach used in the experiments attained an average class accuracy of approximately 55%, the multitemporal scheme achieved between 65% and 95%. Similar results in terms of overall accuracy were also observed. Furthermore, compared to two alternative cascade multitemporal classification approaches, the proposed method consistently showed better results.     

Nanomineralogy of evaporative precipitation of efflorescent compounds from coal mine drainage

Efflorescent nanophases(NPs)are found as a transitory accumulation of potentially hazardous elements(PHEs),particularly in tropical climates.The central objective of this study was to investigate the distribution of PHEs with NPs through the evaporative formation structures(EFS)of enormously PHEs-rich coal-mine drainages(CMD).The EFS were studied in natural coal mine drainage for five months in order to determine their geochemical and ecological structures and to assess their position in the reduction of PHEs in nature.The largest coal-fired power plant in South America,located in south Brazil,is used as an example of such a problem.In this work,a novel methodology for the analysis of PHEs in CMD precipitates is proposed for this affected coal area.The analytical method,combining X-Ray Diffraction(XRD)and advanced electron microscopies,shows the importance of nanomineralogy in understanding different circumstances of coal contamination.Several ultrafine-nanoparticles(UNPs)were identified in the sampled soils and river sediments together with the PHEs.A decrease in PHEs was identified in association with UNPs.However,further investigations are required with regard to the mobility of PHEs in water,atmosphere,soils,and sediments.The EPS was thoroughly studied,acquiring suitable understanding with investigational facts for Ca and Fe-sulphates,pickeringite,and several amorphous phases.     

Heterogeneous distribution of phosphorus in olivine from otherwise well-equilibrated spinel peridotite xenoliths and its implications for the mantle geochemistry of lithium

The major- and trace-element abundances of the coexisting phases of four metasomatized spinel peridotite xenoliths from the Anakies locality (SE Australia) were determined by electron microprobe and laser-ablation ICP-MS. The compositions of all phases are remarkably homogeneous, with the exception of phosphorus (P), lithium (Li) and sodium (Na) in olivine. These three elements are enriched in large parts of most olivine crystals due to a second metasomatic episode. Apart from these elements, all phases are in mutual equilibrium with respect to both their major- and trace-element compositions. Li and Na show a strong correlation with P in olivine, although molar Li + Na are an order of magnitude less than molar P, indicating that the substitution mechanism of these elements is more complex than the simple charge-balanced coupled exchange ^IVSi⁴⁺ + ^VI(FeMg)²⁺ = ^IVP⁵⁺ + ^VI(LiNa)⁺. We suggest that Li and Na are decorating octahedral-site cation vacancies formed by the original incorporation of P. Elemental maps revealed that the P zoning patterns are concentric in a few large olivine porphyroblasts, but form irregular patches in most crystals. This distribution of P is proposed to be the result of a two-stage process, whereby the initial concentric zoning, caused by its exceptionally sluggish diffusion after metasomatic influx, is broken up by extensive sub-solidus deformation and recrystallization, attesting to large grain-scale strains even within the lithosphere. Such strains must be an efficient means of ensuring trace-element equilibrium during partial melting. The association of Li with P in olivine may help to explain the variability of Li abundances in mantle minerals and to interpret Li diffusion experiments and Li isotopic fractionation.     

Assessment of susceptibility to landslides through geographic information systems and the logistic regression model

Natural Hazards - The increase in the frequency of natural disasters in recent years and its consequent social, economic and environmental impacts make it possible to prioritize areas of risk as an...     

Tephra glass chemistry provides storage and discharge details of five magma reservoirs which fed the 75 ka Youngest Toba Tuff eruption,northern Sumatra

The Youngest Toba Tuff contains five distinct glass populations, identified from Ba, Sr and Y compositions, termed PI (lowest Ba) – PV (highest Ba), representing five compositionally distinct pre-eruptive magma batches that fed the eruption. The PI–PV compositions display systematic changes, with higher FeO, CaO, MgO, TiO₂ and lower incompatible element concentrations in the low-SiO₂ PIV/PV, than the high-SiO₂ PI–PIII compositions. Glass shard abundances indicate PIV and PV were the least voluminous magma batches, and PI and PIII the most voluminous. Pressure estimates using rhyolite-MELTS indicate PV magma equilibrated at ~6 km, and PI magma at ~3.8 km. Glass population proportions in distal tephra and proximal (caldera-wall) material describe an eruption which commenced by emptying the deepest PIV and PV reservoirs, this being preferentially deposited in a narrow band across southern India (possibly due to jet-stream and/or plinian eruption transport), and as abundant pumice clasts in the lowermost proximal ignimbrites. Later, shallower magma reservoirs erupted, with PI being the most abundant as the eruption ended, sourcing the majority of distal ash from co-ignimbrite clouds (PI- and PIII-dominant), where associated ignimbrites isolated earlier (PIV- and PV-rich) deposits. This study shows how analysis of tephra glass compositional data can yield pre-eruption magma volume estimates, and enable aspects of magma storage conditions and eruption dynamics to be described.     

Macrofauna associated to Mycale microsigmatosa (Porifera, Demospongiae) in Rio de Janeiro State, SE Brazil

The macrofauna (endo- and epi-biotic) associated to the sponge Mycale (Carmia) microsigmatosa Arndt, 1927 was studied at three sites in Rio de Janeiro State, Brazil (Arraial do Cabo, Niterói, and Rio de Janeiro). A total of 2235 individuals (over 1 mm long) of 75 invertebrate species were found associated to 19 specimens of the sponge. The most abundant and diverse taxa were the crustaceans (83%, 31 spp.), polychetes (10%, 18 spp.), and molluscs (3.7%, 15 spp.). Cnidarians, platyhelminthes, ascidians, echinoderms, pycnogonids, bryozoans, and sponges were also represented. Amphipod crustaceans were the dominant group, comprising 61% of all individuals collected. Species richness and abundance of associated fauna were highly correlated with sponge volume, but diversity and evenness were not. The site of collection influenced the species composition of the fauna associated to M. microsigmatosa but did not change significantly its diversity, abundance, richness, and dominance patterns of higher taxa. Pregnant females and juvenile stages of 29% of the species associated, including crustaceans, molluscs, echinoderms, and pycnogonids were frequently found inside M. microsigmatosa. Although many of these organisms do occur and reproduce in other habitats outside the sponge as well, M. microsigmatosa is also important for their reproduction and survivorship, thus contributing for the maintenance of biodiversity in Southwestern Atlantic sublittoral rocky shores.     

Predicting coffee yield based on agroclimatic data and machine learning

Theoretical and Applied Climatology - Climate directly and indirectly influences agriculture, being the main responsible for low and high yields. Prior knowledge on yield helps coffee farmers in...     

Juvenile contribution of the Neoproterozoic Rio Negro Magmatic Arc (Ribeira Belt,Brazil): Implications for Western Gondwana amalgamation

The ca. 790–600 Ma Rio Negro Complex (RNC) of the Ribeira belt (Brazil) consists of a plutonic portion of a magmatic arc built by the E-vergent subduction of the ESE border of the São Francisco paleoplate during the amalgamation of Western Gondwana.The plutonic series comprises low- to medium-K granitoids (ca. 790–620 Ma) and high-K granitoids and shoshonite rocks (ca. 610–605). The age span of 185 m.y. is suggestive of a long history of arc-related magmatism, continuously or not in time. The Nd isotopic signatures of the RNC consist of εNd(t) ratios from ? 3 to + 5 for the medium-K series shoshonite series and from ? 14 to ? 3 for the younger high-K group. This time-dependent trend of Nd isotopes is indicative of progressive maturity of the arc over time. The same evolution is indicated by Sr data, as the medium-K rocks have ⁸⁷Sr/⁸⁶Sr initial ratios < 0.705 while the high-K rocks yield values between 0.705 and 0.710. The predominance of intermediate rocks over mafic ones suggests an initial intra-oceanic to transitional stage, possibly developed in a distal portion of a passive margin, such as the Japanese arc, evolving to a more developed, differentiated felsic rock associations.The role of transform fault zones, such as the Luanda shear zone, is emphasized in order to explain the consumption of a wide oceanic plate in the inner portion of Western Gondwana.     

The Serra da Graciosa A-type Granites and Syenites, southern Brazil: Part 2: Petrographic and mineralogical evolution of the alkaline and aluminous associations

The Serra da Graciosa Granites and Syenites comprise five distinct plutons in the Brasiliano/Pan-African Graciosa A-type Province, southern Brazil. Six petrographic series can be identified in these plutons: (1) Alkaline series 1, composed of amphibole-bearing alkali feldspar syenites with varied mafic mineralogy and quartz contents, from alkali feldspar syenites with calcic amphibole, clinopyroxene, olivine and allanite to alkali feldspar quartz syenites with sodic–calcic amphibole and chevkinite–perrierite and to alkali feldspar granites with sodic amphibole; (2) Alkaline series 2, characterized by amphibole-bearing alkali feldspar granites, with limited modal variations but amphibole compositions also varying from calcic to sodic; (3) Alkaline series 3, of limited occurrence, which includes alkali feldspar syenites with olivine and clinopyroxene and no amphibole; (4) Aluminous series 1, of widespread occurrence, with various petrographic facies of biotite granites with amphibole; (5) Aluminous series 2, characterized by alkali feldspar granites with biotite and only minor amphibole; (6) Monzodiorites, typically with biotite, calcic amphibole and augitic clinopyroxene, partially mingled with granitic magmas. The mafic minerals present are, in general, Fe-rich with correspondingly low Mg and Al contents. In Alkaline series 1, amphiboles crystallized in progressively more oxidizing and alkaline conditions, while in Alkaline series 2, the initial conditions were somewhat more oxidizing and shifted to reducing in the final stages. In Aluminous series 1 and Aluminous series 2, amphiboles are calcic and comparatively homogeneous. The amphiboles in the monzodioritic rocks, while also homogeneous, are more Mg-rich and show compositions quite distinct from the calcic varieties in the other associations, and this is also the case for clinopyroxene. Mg# in biotite decreases from the monzodioritic rocks to Aluminous series 1 and further to Aluminous series 2. Contrasting evolution of the various associations suggests that several coeval magmatic series are present in the Serra da Graciosa granites.     

Effects of Bioirrigation and Salinity on Arsenic Distributions in Ferruginous Concretions from Salt Marsh Sediment Cores (Southern Brazil)

Arsenic (As), iron (Fe), and manganese (Mn) contents were measured in sediment nodules and associated pore waters obtained from sediment cores collected from a salt marsh on Pólvora Island (southern Brazil). Sediment cores were obtained when brackish water dominated the estuary, at two different environments: an unvegetated mudflat colonized by crabs (Neohelice granulata), and a low intertidal stand vegetated by Spartina alterniflora. We determined the percentage of nodules in each depth interval of the cores, along with redox potential, and As, Fe, and Mn contents of the nodules. The mineralogy of the nodules was investigated, and results showed they are mainly composed by quartz, phyllosilicates, and amorphous Fe–Mn oxides/oxyhydroxides. Pore water results showed that bioturbation by local crabs supports oxygen penetration to depths of ca. 25 cm below the salt marsh surface, with lower Fe contents in pore water associated with the brackish period. However, S. alterniflora growth appears to have a greater impact on sediment geochemistry of Fe, Mn, and possibly As due to sulfate reduction and the associated decrease in pore water pH. Higher Fe concentrations were observed in the pore waters during the period of brackish water dominance, which also corresponded to the S. alterniflora growth season. The study demonstrates that differences in geochemical conditions (e.g., Fe content) that can develop in salt marsh sediments owing to different types of bioirrigation processes (i.e., bioirrigation driven by crabs versus that related to the growth of S. alterniflora) play important roles in the biogeochemical cycling of As.