Mantle wedge temperatures and their potential relation to volcanic arc location

The mechanisms underpinning the formation of a focused volcanic arc above subduction zones are debated. Suggestions include controls by: (i) where the subducting plate releases water, lowering the solidus in the overlying mantle wedge; (ii) the location where the mantle wedge melts to the highest degree; and (iii) a limit on melt formation and migration imposed by the cool shallow corner of the wedge. Here, we evaluate these three proposed mechanisms using a set of kinematically-driven 2D thermo-mechanical mantle-wedge models in which subduction velocity, slab dip and age, overriding-plate thickness and the depth of decoupling between the two plates are systematically varied. All mechanisms predict, on the basis of model geometry, that the arc-trench distance, D, decreases strongly with increasing dip, consistent with the negative D-dip correlations found in global subduction data. Model trends of sub-arc slab depth, H, with dip are positive if H is wedge-temperature controlled and overriding-plate thickness does not exceed the decoupling depth by more than 50 km, and negative if H is slab-temperature controlled. Observed global H-dip trends are overall positive. With increasing overriding plate thickness, the position of maximum melting shifts to smaller H and D, while the position of the trenchward limit of the melt zone, controlled by the wedge's cold corner, shifts to larger H and D, similar to the trend in the data for oceanic subduction zones. Thus, the limit imposed by the wedge corner on melting and melt migration seems to exert the first-order control on arc position

Continental margin subsidence from shallow mantle convection: Example from West Africa

Spatial and temporal evolution of the uppermost convecting mantle plays an important role in determining histories of magmatism, uplift, subsidence, erosion and deposition of sedimentary rock. Tomographic studies and mantle flow models suggest that changes in lithospheric thickness can focus convection and destabilize plates. Geologic observations that constrain the processes responsible for onset and evolution of shallow mantle convection are sparse. We integrate seismic, well, gravity, magmatic and tomographic information to determine the history of Neogene-Recent (+100 °C providing ∼103 m of support. Beneath the Mauritania basin average excess temperatures are <−100 °C drawing down the lithosphere by ∼102 to 103 m. Up- and downwelling mantle has generated a bathymetric gradient of ∼1/300 at a wavelength of ∼103 km during the last ∼23 Ma. Our results suggest that asthenospheric flow away from upwelling mantle can generate downwelling beneath continental margins

Seleção de linhagens de feijão-caupi para o cerrado do Amapá.

O cerrado do Amapá possui amplas características para a produção de alimentos, sendo o feijão-caupi uma grande opção. Assim, selecionar cultivares para utilização no processo mecanizado deve ser uma meta a ser seguida, sendo este o objetivo do experimento

Genótipos prostrados de feijão-caupi no Cerrado do Amapá.

O cerrado do Estado do Amapá apresenta totais condições para a produção de grãos, sendo o feijão-caupi uma das opções mais viáveis. Assim, selecionar cultivares para este ambiente deve ser uma das metas da pesquisa. No caso em estudo, o experimento objetivou avaliar linhagens de porte prostrado e semi-prostrado. Em Latossolo Amarelo, clima do tipo Ami, usou-se o delineamento experimental de blocos ao acaso e quatro repetições, adubação de 80 kg ha-1 (superfosfato triplo) e 50 kg ha-1 (cloreto de potássio). A semeadura manual ocorreu em fileiras espaçadas de 0,80 m, com área útil de 8 m2 e população de 100 mil plantas ha-1. A análise de variância mostrou diferença significativa pelo teste de Tukey (p< 0,05). O melhor desempenho produtivo de 1.216,7 kg ha-1 foi da linhagem MNC02-676F-1, que apresenta grão da subclasse mulato, seguida pela cultivar BRS-Pajeú com 1.119,0 kg ha-1, com grão da subclasse sempre verde. A linhagem BRS Juruá alcançou menor período de floração, enquanto o maior comprimento de vagem foi do genótipo MNC02-677F-2. Todas as linhagens mostraram tolerância à incidência de doenças.Disponível em: http://www.conac2012.org/resumos/pdf/133c.pdf. Acesso em: 22 jul. 2013

Determinação de características químicas, físico-químicas e propriedades funcionais de carne de caprinos do Nordeste brasileiro.

bitstream/CNPAT-2010/5604/1/Pa-034.pd

Evidence of subduction-related thermal and compositional heterogeneity below the United States from transition zone receiver functions

The subduction of the Farallon Plate has altered the temperature and composition of the mantle transition zone (MTZ) beneath the United States. We investigate MTZ structure by mapping P‐to‐S conversions at mineralogical phase changes using USArray waveform data and theoretical seismic profiles based on experimental constraints of phase transition properties as a function of temperature and composition. The width of the MTZ varies by about 35 km over the study region, corresponding to a temperature variation of more than 300 K. The MTZ is coldest and thickest beneath the eastern United States where high shear velocity anomalies are tomographically resolved. We detect intermittent P‐to‐S conversions at depths of 520 km and 730 km. The conversions at 730‐km depth are coherent beneath the southeastern United States and are consistent with basalt enrichment of about 50%, possibly due to the emplacement of a fragment of an oceanic plateau (i.e., the Hess conjugate)

Global variation of body‐wave attenuation in the upper mantle from teleseismic P wave and S wave spectra

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95463/1/grl27917.pd

Validation and assessment of variant calling pipelines for next-generation sequencing

Background: The processing and analysis of the large scale data generated by next-generation sequencing (NGS) experiments is challenging and is a burgeoning area of new methods development. Several new bioinformatics tools have been developed for calling sequence variants from NGS data. Here, we validate the variant calling of these tools and compare their relative accuracy to determine which data processing pipeline is optimal. Results: We developed a unified pipeline for processing NGS data that encompasses four modules: mapping, filtering, realignment and recalibration, and variant calling. We processed 130 subjects from an ongoing whole exome sequencing study through this pipeline. To evaluate the accuracy of each module, we conducted a series of comparisons between the single nucleotide variant (SNV) calls from the NGS data and either gold-standard Sanger sequencing on a total of 700 variants or array genotyping data on a total of 9,935 single-nucleotide polymorphisms. A head to head comparison showed that Genome Analysis Toolkit (GATK) provided more accurate calls than SAMtools (positive predictive value of 92.55% vs. 80.35%, respectively). Realignment of mapped reads and recalibration of base quality scores before SNV calling proved to be crucial to accurate variant calling. GATK HaplotypeCaller algorithm for variant calling outperformed the UnifiedGenotype algorithm. We also showed a relationship between mapping quality, read depth and allele balance, and SNV call accuracy. However, if best practices are used in data processing, then additional filtering based on these metrics provides little gains and accuracies of >99% are achievable. Conclusions: Our findings will help to determine the best approach for processing NGS data to confidently call variants for downstream analyses. To enable others to implement and replicate our results, all of our codes are freely available at http://metamoodics.org/wes

Linhagens eretas de feijão-caupi avaliadas no Amapá: safra 2010/2011.

bitstream/item/84996/1/AP-2012-Comunicado-tecnico-131-feijaocaupi-ebook-final.pd