984 resultados para Wavelet transformation


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Electroless nickel-phosphorus deposits with 5-8 wt% P and 3-5 wt% P were analysed for the effects of continuous heating on the crystallization kinetics and phase transformation behaviour of the deposits. The as-deposited coatings consist of a mixture of amorphous and microcrystalline nickel phases, featuring in their X-ray diffraction patterns. Continuous heating processes to 300C-800C at 20C/min were carried out on the deposits in a differential scanning calorimetric apparatus. The subsequent X-ray diffraction analyses show that the sequence of phase transformation process was: amorphous phase + microcrystalline nickel, f.c.c. nickel + Ni3P stable phases. Preferred orientation of nickel {200} plane developed in the deposits after the heating processes. Differential scanning calorimetry of the deposits indicates that the crystallization temperatures increased with decreasing phosphorus content, and increasing heating rate. Crystallization activation energies of the deposits (230 and 322 kJ/mol, respectively) were calculated using the peak temperatures of crystallization process, from the differential scanning calorimetric curves at the heating rates ranging from 5 to 50C/min. It was found that the deposit with lower phosphorus content has higher activation energy.

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A new application of wavelet analysis is presented that utilizes the inherent phase information residing within the complex Morlet transform. The technique is applied to a weak solar magnetic network region, and the temporal variation of phase difference between TRACE 1700 Angstrom and SOHO/SUMER C II 1037 Angstrom intensities is shown. We present, for the first time in an astrophysical setting, the application of wavelet phase coherence, including a comparison between two methods of testing real wavelet phase coherence against that of noise. The example highlights the advantage of wavelet analysis over more classical techniques, such as Fourier analysis, and the effectiveness of the former to identify wave packets of similar frequencies but with differing phase relations is emphasized. Using cotemporal, ground-based Advanced Stokes Polarimeter measurements, changes in the observed phase differences are shown to result from alterations in the magnetic topology.

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Osteopontin (OPN) is a predominantly secreted extracellular matrix glycophosphoprotein which binds to alpha v-containing integrins and has an important role in malignant cell attachment and invasion. High OPN expression in the primary tumor is associated with early metastasis and poor outcome in human breast and other cancers. Forced OPN overexpression in benign cells may induce neoplastic-like cell behaviour including increased attachment and invasion in vitro as well as the ability to metastasize in vivo. Conversely, OPN inhibition by antisense cDNA impedes cell growth and tumor forming capacity. OPN is not mutationally activated in cancer but its expression is regulated by Wnt/Tcf signaling, steroid receptors, growth factors, ras, Ets and AP-1 transcription factors. Presumably these factors are implicated in induction of OPN overexpression in cancer. Greater understanding of the role of OPN in neoplastic change and its transcriptional regulation may enable development of novel cancer treatment strategies

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Contribution of co-operatives has been demonstrated since the 1970s as the main development line in agricultural production in Cuba. In contrast, there has been a late recognition of urban co-operatives, even if the need of transformations based on the realization of property in different territorial scenarios had been identified. The article analyses the reform processes launched since the first decade of the 21st century focusing on the nature of the initiatives fostering formation and promotion of nonagricultural co-operatives including follow up of their performance. The potential and limitations of the recent experiences are examined in order to reflect on the organizational processes and transformations from the point of view of their members. To conclude, some questions are posed about whether these co-operatives are capable of avoiding the impact of earlier employment circumstances and of developing strategies aimed at reinforcing voluntary membership and autonomy on which they are founded.

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This research arises due to the current restructuring process in which is immersed the Spanish banking sector. The above mentioned process is carried out to try to reduce the doubts on the viability of the bank companies to average and long term and to be able to return again the confidence in the sector. Though the economic and financial crisis has concerned the whole banking sector, the subsector of the Spanish savings banks is the one that has experienced a major number of integrations (articulated by means of mergers, absorptions and across Institutional Protection Schemes -IPSs-), and the one that has met submitted to the bancarization process. Considering what has been said, the present paper analyses Spanish saving banks to try to discern whether thanks to that process the objectives pursued by the bank rearrangement have been fulfilled. To do this, the evolution of some important financial variables will be studied over a long period of time (1999-2012). The results suggest that not all the savings banks have seen improved their ratios of efficiency, solvency, financial gap and social work, which indicates that there is still much to be done in order to rectify the problems affecting the studied sector.

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A system for the identification of power quality violations is proposed. It is a two-stage system that employs the potentials of the wavelet transform and the adaptive neurofuzzy networks. For the first stage, the wavelet multiresolution signal analysis is exploited to denoise and then decompose the monitored signals of the power quality events to extract its detailed information. A new optimal feature-vector is suggested and adopted in learning the neurofuzzy classifier. Thus, the amount of needed training data is extensively reduced. A modified organisation map of the neurofuzzy classifier has significantly improved the diagnosis efficiency. Simulation results confirm the aptness and the capability of the proposed system in power quality violations detection and automatic diagnosis