737 research outputs found
Multiplexing of encrypted data using fractal masks
This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.002895. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawIn this Letter, we present to the best of our knowledge a new all-optical technique for multiple-image encryption and multiplexing, based on fractal encrypting masks. The optical architecture is a joint transform correlator. The multiplexed encrypted data are stored in a photorefractive crystal. The fractal parameters of the key can be easily tuned to lead to a multiplexing operation without cross talk effects. Experimental results that support the potential of the method are presented.This research was performed under grants TWAS-UNESCO Associateship Scheme at Centres of Excellence in the South, CONICET No. 0863 (Argentina), ANCYT PICT 1167 (Argentina), and Facultad de Ingenieria, Universidad Nacional de La Plata No. 11/I125 (Argentina), Sostenibilidad 2011-2012, and CODI (Universidad de Antioquia-Colombia). W. D. Furlan and J. A. Monsoriua acknowledge financial support from Ministerio de Economia y Competitividad (grant FIS2011-23175), Generalitat Valenciana (grant PROMETEO2009-077), and Universitat Politecnica de Valencia (grants PAID-05-11 and PAID-02-11), Spain.Barrera, J.; Tebaldi, M.; Amaya, D.; Furlan, W.; Monsoriu Serra, JA.; Bolognini, NA.; Torroba, RD.... (2012). Multiplexing of encrypted data using fractal masks. Optics Letters. 37(14):2895-2897. doi:10.1364/OL.37.002895S289528973714Refregier, P., & Javidi, B. (1995). Optical image encryption based on input plane and Fourier plane random encoding. Optics Letters, 20(7), 767. doi:10.1364/ol.20.000767Matoba, O., & Javidi, B. (1999). Encrypted optical memory system using three-dimensional keys in the Fresnel domain. Optics Letters, 24(11), 762. doi:10.1364/ol.24.000762Unnikrishnan, G., Joseph, J., & Singh, K. (2000). Optical encryption by double-random phase encoding in the fractional Fourier domain. Optics Letters, 25(12), 887. doi:10.1364/ol.25.000887Nomura, T. (2000). Polarization encoding for optical security systems. Optical Engineering, 39(9), 2439. doi:10.1117/1.1288369Tebaldi, M., Furlan, W. D., Torroba, R., & Bolognini, N. (2009). Optical-data storage-readout technique based on fractal encrypting masks. Optics Letters, 34(3), 316. doi:10.1364/ol.34.000316Situ, G., & Zhang, J. (2005). Multiple-image encryption by wavelength multiplexing. Optics Letters, 30(11), 1306. doi:10.1364/ol.30.001306Liu, Z., & Liu, S. (2007). Double image encryption based on iterative fractional Fourier transform. Optics Communications, 275(2), 324-329. doi:10.1016/j.optcom.2007.03.039Hwang, H.-E., Chang, H. T., & Lie, W.-N. (2009). Multiple-image encryption and multiplexing using a modified Gerchberg-Saxton algorithm and phase modulation in Fresnel-transform domain. Optics Letters, 34(24), 3917. doi:10.1364/ol.34.003917Matoba, O., & Javidi, B. (1999). Encrypted optical storage with angular multiplexing. Applied Optics, 38(35), 7288. doi:10.1364/ao.38.007288Fredy Barrera, J., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiplexing encryption–decryption via lateral shifting of a random phase mask. Optics Communications, 259(2), 532-536. doi:10.1016/j.optcom.2005.09.027Henao, R., Rueda, E., Barrera, J. F., & Torroba, R. (2010). Noise-free recovery of optodigital encrypted and multiplexed images. Optics Letters, 35(3), 333. doi:10.1364/ol.35.000333Barrera, J. F., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiple image encryption using an aperture-modulated optical system. Optics Communications, 261(1), 29-33. doi:10.1016/j.optcom.2005.11.055Mosso, F., Barrera, J. F., Tebaldi, M., Bolognini, N., & Torroba, R. (2011). All-optical encrypted movie. Optics Express, 19(6), 5706. doi:10.1364/oe.19.005706Monsoriu, J. A., Saavedra, G., & Furlan, W. D. (2004). Fractal zone plates with variable lacunarity. Optics Express, 12(18), 4227. doi:10.1364/opex.12.00422
Hydrogen peroxide is a neuronal alarmin that triggers specific RNAs, local translation of Annexin A2, and cytoskeletal remodeling in Schwann cells
Schwann cells are key players in neuro-regeneration: They sense "alarm" signals released by degenerating nerve terminals and differentiate toward a proregenerative phenotype, with phagocytosis of nerve debris and nerve guidance. At the murine neuromuscular junction, hydrogen peroxide (H2O2) is a key signal of Schwann cells' activation in response to a variety of nerve injuries. Here we report that Schwann cells exposed to low doses of H2O2 rewire the expression of several RNAs at both transcriptional and translational levels. Among the genes positively regulated at both levels, we identified an enriched cluster involved in cytoskeleton remodeling and cell migration, with the Annexin (Anxa) proteins being the most represented family. We show that both Annexin A2 (Anxa2) transcript and protein accumulate at the tips of long pseudopods that Schwann cells extend upon H2O2 exposure. Interestingly, Schwann cells reply to this signal and to nerve injury by locally translating Anxa2 in pseudopods, and undergo an extensive cytoskeleton remodeling. Our results show that, similarly to neurons, Schwann cells take advantage of local protein synthesis to change shape and move toward damaged axonal terminals to facilitate axonal regeneration
TrkA is amplified in malignant melanoma patients and induces an anti-proliferative response in cell lines.
Background: The nerve growth factor (NGF) receptor tyrosine-kinase TrkA is a well-known determinant of the melanocytic lineage, through modulation of the MAPK and AKT cascades. While TrkA gene is frequently rearranged in cancers, its involvement in malignant melanoma (MM) development is still unclear.
Methods: We analyzed a dataset of primary cutaneous MM (n = 31) by array comparative genomic hybridization (aCGH), to identify genomic amplifications associated with tumor progression. The analysis was validated by genomic quantitative PCR (qPCR) on an extended set of cases (n = 64) and the results were correlated with the clinical outcome. To investigate TrkA molecular pathways and cellular function, we generated inducible activation of the NGF-TrkA signaling in human MM cell lines.
Results: We identified amplification of 1q23.1, where the TrkA locus resides, as a candidate hotspot implicated in the progression of MM. Across 40 amplicons detected, segmental amplification of 1q23.1 showed the strongest association with tumor thickness. By validation of the analysis, TrkA gene amplification emerged as a frequent event in primary melanomas (50 % of patients), and correlated with worse clinical outcome. However, experiments in cell lines revealed that induction of the NGF-TrkA signaling produced a phenotype of dramatic suppression of cell proliferation through inhibition of cell division and pronounced intracellular vacuolization, in a way straightly dependent on NGF activation of TrkA. These events were triggered via MAPK activity but not via AKT, and involved p21(cip1) protein increase, compatibly with a mechanism of oncogene-induced growth arrest.
Conclusions: Taken together, our findings point to TrkA as a candidate oncogene in MM and support a model in which the NGF-TrkA-MAPK pathway may mediate a trade-off between neoplastic transformation and adaptive anti-proliferative response
Metodologia Diagnóstica para as Unidades de Conservação Estaduais do Espírito Santo: Condições para sua Gestão, Prevenção e Combate aos Incêndios Florestais.
TEBALDI, André Luiz Campos. Metodologia Diagnóstica para as Unidades
de Conservação Estaduais do Espírito Santo: Condições para sua Gestão
e para Prevenção e Combate aos Incêndios Florestais. 2010. Dissertação
(Mestrado em Ciências Florestais) Universidade Federal do Espírito Santo,
Alegre ES. Orientador Prof. Dr. Nilton César Fiedler.
A pesquisa teve o objetivo principal desenvolver metodologia
diagnóstica para as Unidades de Conservação estaduais do Espírito Santo:
Condições para sua gestão, prevenção e combate aos incêndios florestais.
Buscou-se trabalhar com seis objetivos específicos sendo eles: caracterizar as
condições de gestão e infraestrutura; diagnosticar a disponibilidade quantitativa
de pessoal e equipamentos para prevenção e combate aos incêndios florestais;
identificar os principais grupos de causa das ocorrências de incêndios florestais
relacionando-as com as principais ameaças aos ecossistemas; identificar a
distribuição das classes de tamanho das áreas queimadas, identificar os
principais tipos de incêndios; diagnosticar as principais atividades de prevenção
desenvolvidas. A análise contou com a participação de todos os gestores das
dezesseis Unidades de Conservação estaduais criadas até o ano de 2009. Os
resultados indicaram que a Reserva Biológica de Duas Bocas possui melhores
condições para gestão e infraestrutura (82%) e a Reserva de Desenvolvimento
Sustentável Concha Dostra possui piores condições (5%). O Parque Estadual
de Itaúnas apresentou maior déficit de pessoal. Na disponibilidade de
equipamentos operacionais, observou-se que 75% das Unidades de proteção
integral estão com déficit. Na relação de ferramentas identificou-se que o
Parque Estadual da Cachoeira da Fumaça apresentou o maior déficit e não há
equipamentos de proteção individual nas Unidades. A infraestrutura
inadequada (14%) e a caça (12%) são as principais ameaças às Unidades
estaduais. Mais de 50% dos incêndios nas Unidades estaduais são de
superfície com predominância de área queimada variando de 0,1 à 40
hectares. Aproximadamente 40% das causas são queimas para limpeza e 20%
incendiários. As principais atividades preventivas realizadas são integração
interinstitucional e vigilância da unidade (22%). Os resultados servirão como
uma eficiente ferramenta de planejamento e gestão para o Governo do Estado
implementar ações e atividades preventivas nas Unidades de Conservação.
Palavras chave: Meio Ambiente, Área Natural Protegida, Gestão de Unidades
de Conservação, Prevenção e Combate aos Incêndios Florestais
Statistical Process Control of assembly lines in a manufacturing plant: Process Capability assessment
Among the main strategies adopted by companies for enhancing their competitive advantage as well as for improving the internal efficiency is the quality management. Several tools can be involved when dealing with this issue; one of these is the Statistical Process Control, which includes the employment of statistical methods and metrics to monitor and control a process' quality. In this paper, indeed, two statistical metrics are involved for assessing the process capability of a filler machine produced by an Italian company operating in the food context. Specifically, two processes are inspected: the slewing ring-pinion backlash and the handling clamps height check, both showing excellent performances after having carried out the control and provided appropriate adjustments. Results are also compared with those obtained from the Six Sigma theory, another tool involved for quality controls which is in line with principles of lean manufacturing. Moreover, for the second process, a software was implemented for speeding up operations and achieving benefits in terms of time. The reliability of these analysis is confirmed by the application of the ANOVA Gage R&R tool, which allowed to assess the precision of the measurement system involved
Economic evaluation of automated guided vehicles usage in a food company
Nowadays, companies are more and more attracted and interested by the possibility of automating processes which can be easily carried out by devices or machines instead of employees, allowing saving in costs, higher productivity and flexibility. Among the most spread ways of automating processes, more precisely in this specific case the flow of materials, the Automated Guided Vehicles (AGVs) stand out. But the main question that everyone asks is the following: is it convenient or not? In this paper, the answer is provided for a company operating in the food context, which intends to automate the transport of raw ingredients from the kitchens where they are produced and prepared to the filling lines; to this end, an economic feasibility study is carried out, taking into account three different levels of automation for three different lines. Results from all the three scenarios demonstrate the convenience in terms of achievable revenues, saved hours and manpower, and will support the management in their operational decisions
Crossover component in non critical dissipative sandpile models
The effect of bulk dissipation on non critical sandpile models is studied
using both multifractal and finite size scaling analyses. We show numerically
that the local limited (LL) model exhibits a crossover from multifractal to
self-similar behavior as the control parameters and turn
towards their critical values, i.e. and . The critical exponents are not universal and exhibit a continuous
variation with . On the other hand, the finite size effects for the
local unlimited (LU), non local limited (NLL), and non local unlimited (NLU)
models are well described by the multifractal analysis for all values of
dissipation rate . The space-time avalanche structure is studied in
order to give a deeper understanding of the finite size effects and the origin
of the crossover behavior. This result is confirmed by the calculation of the
susceptibility.Comment: 13 pages, 10 figures, Published in European Physical Journal
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