Ensemble Learning for Blind Image Separation and Deconvolution

Introduction Previous work on Blind Source Deconvolution has focused mainly on the problem of deconvolving sound samples. It is assumed that the observed sound samples are temporally convolved versions of the true source samples. Blind Deconvolution algorithms have fallen into two types, those where the inverse of the convolution lter is learnt [1],[3] and those where the aim is to learn the lter itself [1]. When applying these ideas to the problem of deconvolving images two problems become apparent. Firstly in many real data sets (for instance the images generated by telescopes observing the sky or the power spectrum from a Nuclear Magnetic Resonance (NMR) spectrometer) the pixel values correspond to intensities. So the pixel values must be positive. The standard blind separation approaches of assuming that the sources are distributed as 1 cosh [3] or mixtures of Gaussians [2] lose this positivity of the source images. Deconvolution without a positivity co

Qualidade pós-colheita de frutos de tomate cv. Andréa tratados com etileno Postharvest quality of tomato fruits cv. Andréa treated with ethylene

O tomate é uma das principais hortaliças cultivadas no Brasil e tratamentos que propiciem o controle do amadurecimento são extremamente desejáveis. Avaliou-se a qualidade pós-colheita de tomates tipo italiano tratados com etileno. Tomates 'Andréa' foram colhidos em campos de produção comercial no estádio verde-maduro, selecionados para presença de danos externos e classificados quanto ao tamanho e cor e posteriormente foram tratados com 100 µL L-1 de etileno. Os ensaios foram planejados com delineamento inteiramente casualizado em esquema fatorial com quatro tratamentos e quinze repetições (n=10). Após a aplicação, os frutos foram divididos em dois lotes. Um lote permaneceu a 20º±1ºC e outro foi mantido a 12,5º±1ºC, ambos sob umidade relativa 90±5%. Tomates do tratamento controle foram mantidos nas mesmas condições de temperatura e umidade relativa. Os frutos foram avaliados após cada mudança de estádio de amadurecimento para as seguintes variáveis: coloração externa (L*a*b*), perda de massa, sólidos solúveis totais, acidez titulável e teor de ácido ascórbico. A aplicação de etileno não influenciou de maneira significativa as variáveis químicas e físicas estudadas. Frutos armazenados à temperatura de 20ºC demonstraram maior porcentagem de perda de massa ao longo do amadurecimento, com média de 2,60%. A relação brix/acidez apresentou pouca variação entre os tratamentos avaliados. Frutos do tratamento controle e mantidos à temperatura de 20ºC apresentaram mudança de coloração mais rápida no início dos experimentos, não sendo observada posteriormente diferença significativa no desenvolvimento da cor dos tratamentos avaliados. O tratamento com etileno não acelerou de forma significativa o amadurecimento de tomates 'Andréa' armazenado sob as duas temperaturas estudadas.<br>Tomatoes are one of the most important vegetable crops grown in Brazil and treatments that facilitate ripening control are extremely desirable. The present work was carried out aiming to evaluate postharvest quality of roma-type tomatoes treated with ethylene. 'Andréa' tomatoes were harvested in commercial fields at the mature-green stage, were graded for size and color, and treated with ethylene (100 µL L-1) for 48 hours at 20º±1ºC and relative humidity of 90±5%. The experiments were carried out using a completely randomized design with four treatments and fifteen replicates (n=10). After ethylene application, tomatoes were stored at two temperatures. One lot remained at 20º±1ºC and another one was kept at 12.5º±1ºC and relative humidity of 90±5%. Control fruits were kept in the same storage conditions of temperature and relative humidity. For each maturity color change, the following analyses were carried out: color indexes (L *, a* and the b * and its relations), water loss (%), soluble solids (ºBrix), titratable acidity (g 100g-1), and ascorbic acid (mg 100g-1). Ethylene application promoted color uniformity in treated fruits. However, there were no significant changes in the other postharvest variables evaluated. Fruits stored at 20ºC showed 2.6% of mass loss during storage. Brix/titratable ratio showed slight variation throughout the experiment. Control fruits stored at 20ºC changed external color earlier than other treatments in the beginning of the trial, showing no significant difference after that. Postharvest ethylene application was not an efficient technique to hasten ripening of 'Andréa' tomatoes

The Cooperative Roles of Two Kinetoplastid-Specific Kinesins in Cytokinesis and in Maintaining Cell Morphology in Bloodstream Trypanosomes

The cytoskeleton of Trypanosoma brucei, a unicellular eukaryote and a parasitic protozoan, is defined by the subpellicular microtubule corset that is arranged underneath the plasma membrane. We recently identified two orphan kinesins, TbKIN-C and TbKIN-D, that cooperate to regulate the organization of the subpellicular microtubule corset and thereby maintain cell morphology in the procyclic form of T. brucei. In this report, we characterize the function of TbKIN-C and TbKIN-D in the bloodstream form of T. brucei and investigate their functional cooperation in both the bloodstream and procyclic forms. TbKIN-C and TbKIN-D form a tight complex in vivo in the bloodstream form. TbKIN-C is strongly enriched at the posterior tip of the cell, whereas TbKIN-D is distributed throughout the cell body at all cell cycle stages. RNAi of TbKIN-C or TbKIN-D in the bloodstream form inhibits cell proliferation and leads to cell death, due to cytokinesis defects. RNAi of TbKIN-C and TbKIN-D also results in defects in basal body segregation, but does not affect the synthesis and segregation of the flagellum and the flagellum attachment zone (FAZ) filament. Knockdown of TbKIN-C and TbKIN-D does not disrupt the organization of the subpellicular microtubule corset, but produces multinucleated cells with an enlarged flagellar pocket and misplaced flagella. Interestingly, depletion of TbKIN-C results in rapid degradation of TbKIN-D and, similarly, knockdown of TbKIN-C destabilizes TbKIN-D, suggesting that formation of TbKIN-C/TbKIN-D complex stabilizes both kinesins and is required for the two kinesins to execute their essential cellular functions. Altogether, our results demonstrate the essential role of the two kinesins in cell morphogenesis and cytokinesis in the bloodstream form and the requirement of heteromeric complex formation for maintaining the stability of the two kinesins

Turbulent amplification of magnetic fields in laboratory laser-produced shock waves

X-ray1-3 and radio4-6 observations of the supernova remnant Cassiopeia A reveal the presence of magnetic fields about 100 times stronger than those in the surrounding interstellar medium. Field coincident with the outer shock probably arises through a nonlinear feedback process involving cosmic rays2,7,8. The origin of the large magnetic field in the interior of the remnant is less clear but it is presumably stretched and amplified by turbulent motions. Turbulence may be generated by hydrodynamic instability at the contact discontinuity between the supernova ejecta and the circumstellar gas9. However, optical observations of Cassiopeia A indicate that the ejecta are interacting with a highly inhomogeneous, dense circumstellar cloud bank formed before the supernova explosion10-12. Herewe investigate the possibility that turbulent amplification is induced when the outer shock overtakes dense clumps in the ambient medium13-15. We report laboratory experiments that indicate the magnetic field is amplified when the shock interacts with a plastic grid. We show that our experimental results can explain the observed synchrotron emission in the interior of the remnant. The experiment also provides a laboratory example of magnetic field amplification by turbulence in plasmas, a physical process thought to occur in many astrophysical phenomena. © 2014 Macmillan Publishers Limited. All rights reserved