Doubly charged Higgs from ee-γ\gamma scattering in the 3-3-1 Model

We studied the production and signatures of doubly charged Higgs bosons in the process $\gamma e^- \rightarrow H^{--}E^+$, where $E^+$ is a heavy lepton, at the $e^-e^+$ International Linear Collider (ILC) and CERN Linear Collider (CLIC). The intermediate photons are given by the Weizs$\ddot{a}$cker-Williams and laser backscattering distributions. We found that significant signatures are obtained by bremsstrahlung and backward Comptom scattering of laser. A clear signal can be obtained for doubly charged Higgs bosons, doubly charged gauge bosons and heavy leptons

Provenance, transport and composition of Dendê Coast beach sands in Bahia, central coast of Brazil

The great physiographic diversity of the Dendê Coast favors the production of different beach sediment types, including bioclastic components. In this study 74 beach samples collected at 2 km intervals were used to evaluate beach sediment composition. For each sample, 300 grains were identified for each grain size class coarser than 0.125 mm, using a binocular microscope. The beach sediments of the Dendê Coast are essentially siliciclastic (80-100%). Quartz is the major component (70-100%). Only at the Tinharé and Boipeba islands bioclasts are major components of beach sands reaching up to 80-100%. These sediments are made up essentially of fragments of Halimeda, reaching percentages up to 70%. Coralline algae and mollusks also contribute significantly to these sediments (up to 30%). The results obtained show that the spatial distribution of the bioclastic components provide important information on the environmental conditions present at the shoreline (energy levels, availability of hard substrates and protected areas, pattern of sediment dispersion) and on the sediment sources as well. The composition of the beach sediments on the Dendê Coast reflects the present day environmental conditions and show that these sediments do not experience significant lateral transport. This situation is favored by an impeded longshore transport that characterizes most of the region. Although, in general, the rivers that discharge on the Dendê Coast appear to transport few sediments to the coastal zone, the presence of heavy minerals, micas and feldspars suggests river contributions to the beach sediments. On the other hand, the coral and coralline algae reefs, besides offering a natural protection to the shoreline, also represent an important source of beach sands.A grande diversidade fisiográfica da Costa do Dendê favorece a deposição de diferentes tipos de sedimentos em suas praias, inclusive sedimentos ricos em carbonato de cálcio. Neste estudo 86 amostras de sedimento foram coletadas, em intervalos de 2 km, para avaliação da composição dos sedimentos praiais. Para cada amostra foram identificados 300 grãos por fração granulométrica maior que 0.125mm, usando uma lupa binocular. Os sedimentos das praias da Costa do Dendê são essencialmente siliciclásticos (80 -100%). O quartzo é o principal componente (70 -100%). Apenas nas ilhas de Tinharé e Boipeba, os bioclastos são os principais componentes alcançando teores entre 80 e 100%. Estes sedimentos são compostos essencialmente de fragmentos de Halimeda, com teores de até 70%. Algas coralinas e moluscos também contribuem significativamente para a composição das areias deste trecho (com teores acima de até 30%). Os resultados obtidos mostram que a análise da distribuição espacial dos componentes bioclásticos fornece informações importantes sobre as condições ambientais na linha de costa (níveis de energia, disponibilidade de substratos duros e suprimento de sedimento), assim como sobre as possíveis fontes de sedimento para a praia. A composição dos sedimentos das praias da Costa do Dendê reflete as condições ambientais atuais, e evidenciam que estes sedimentos não experimentam transporte lateral. Essa situação é favorecida pela situação de transporte litorâneo impedido que caracteriza a maior parte da região. Embora, os rios da região pareçam transportar poucos sedimentos para a zona costeira, a presença de minerais pesados, micas e feldspatos sugerem contribuições fluviais para os sedimentos das praias. Por outro lado, os recifes de coral e algas coralinas, além de oferecerem uma proteção natural para a linha de costa, também representam uma importante fonte de sedimentos para as praias

Rapid growth rates of syndepositional marine aragonite cements in steep marginal slope deposits, Bahamas and Belize

Growth rates of marine botryoidal aragonite cements from steep (35-45[degree]) marginal slope deposits in the Bahamas and Belize have been determined by accelerator mass spectrometer radiocarbon dating of samples taken at the base and top of individual botryoids. The pore-filling cements, which range from approximately 11,000-13,000 years old, grew at average rates of 8-10mm/100 yr with maximum rates > 25mm/100 yr. Radiocarbon dating of coexisting skeletal components indicates that cementation was syndepositional. Microsampling transects across individual botryoids for stable-isotope analyses show little variation in [delta][sup 31]C and [delta][sup 18]O, supporting the conclusion that cementation was extremely rapid. Although the cements show a progressive depletion in isotopic composition of approximately 1[per thousand]([delta][sup 13]C) and 2[per thousand]([delta][sup 18]O) from 13 ka to 11 ka, the average variation ([delta][sub 1]) within individual pore-filling cements, ranging in size 2 mm to 32 mm (bottom to top), was 0.11[per thousand]([delta][sup 13]C) and 0.14[per thousand]([delta][sup 18]O). Results of this study provide the first quantitative data on growth rates of marine carbonate cements in a marginal slope environment. The data indicate that marginal slope deposits may lithify within several tens of years and suggest that geologically instantaneous cementation may be critical in stabilizing steep carbonate slope deposits at or above angles of repose