The gamma-filter-a new class of adaptive IIR filters withrestricted feedback

Generalized feedforward filters, a class of adaptive filters that combines attractive properties of finite impulse response (FIR) filters with some of the power of infinite impulse response (IIR) filters, are described. A particular case, the gamma filter, generalizes Widrow's adaptive transversal filter (adaline) to an infinite impulse response filter. Yet, the stability condition for the gamma filter is trivial, and LMS adaptation is of the same computational complexity as the conventional transversal filter structure. Preliminary results indicate that the gamma filter is more efficient than the adaptive transversal filter. The authors extend the Wiener-Kopf equation to the gamma filter and develop some analysis tools     

Functionalized Microparticles Producing Scaffolds in Combination with Cells

The development of biologically instructive biomaterials with application for tissue regeneration has become the focus of intense research over the last years. This work reports a novel approach for the production of three‐dimensional constructs for tissue engineering applications based on the assembly of chitosan microparticles exhibiting specific biological response with cells. Chitosan microparticles with a size range between 20 and 70 μm are functionalized with platelet derived growth factor (PDFG‐BB). The functionalization is achieved by previous immobilization of an anti‐PDGF‐BB antibody, using a water‐soluble carbodiimide. When incubated with a cocktail of growth factors‐platelet lysates, the previously functionalized particles are able to target PDGF‐BB from the protein mixture. In vitro studies are carried out focusing on the ability of these systems to promote the assembly into a stable 3D construct triggered by the presence of human adipose stem cells, which act as crosslinker agents and induce the formation of a hydrogel network. The presence of immobilized growth factors gives to this system a biological functionality towards control on cell function. It is also bioresponsive, as cells drive the assembly process of the microgel. These versatile biomimetic microgels may provide a powerful tool to be used as an injectable system for non‐invasive tissue engineering applications with additional control over cellular function by creating specific microenvironments for cell growth.     

Positive Quadratic Differential Forms: Topological Equivalence Through Newton Polyhedra

The purpose of this article is to establish conditions under which a positive quadratic differential form is topologically equivalent to its principal part defined by Newton polyhedra. The problem is to study the simultaneous behavior of two foliations in the plane having a common point as a singularity. 2000 Mathematics Subject Classification. Primary: 37C15; Secondary: 34C20, 34A34. The first author was partially supported by FAPESP Grant No. 03/03107-9 and by CNPq Grant No. 306992/2003-5, Brazil. The second author was supported by CNPq-Brazil Grant No. 154150/01-1 and PROCAD-Brazil No. 092/01. The third author was supported by PRONEX No. 76.97.1080/00 and Fapesp-Brazil under Grant No. 97/10735-3.     

Programmable analogue VLSI implementation for asymmetric sigmoid neural activation function and its derivative

A new CMOS VLSI implementation of an asymmetric programmable sigmoid neural activation function, as well as of its derivative, is presented. It consists of two coupled PMOS and NMOS differential pairs with different programmable bias currents that set the upper and lower limits of the sigmoid. The circuit works in the weak inversion region, for low power consumption and exponential envelope, or in strong inversion to achieve higher speeds. The results obtained from the theoretical transfer function, and from the simulations of the circuit implemented in AMI's 0.35 /spl mu/m technology, show a very good match.     

Progress in the diagnosis of hypovitaminosis A: clinical and biochemical correlations

Hypovitaminosis A is a widespread problem, especially among preschool children in many parts of the world. According to the World Health Organization (WHO) estimates, about 100,000 children become blind every year, and many are dying due to vitamin A deficiency while millions of others are suffering from other consequences of vitamin A deficiency such as growth retardation and increased susceptibility to infection. It is, therefore, very important that not only the severe cases of hypovitaminosis A be diagnosed for immediate treatment, but also the marginal cases of vitamin A deficiency in vulnerable populations be diagnosed as early as possible so that appropriate preventive measures be implemented. Available methods for the diagnosis of vitamin A deficiency can be classified into four categories: clinical, biochemical, functional, and dietary. Clinical diagnosis is based on examining ocular and extraocular signs of hypovitaminosis A, and is only useful for the detection of severe cases. Biochemical methods are based on the plasma concentrations of retinol and retinol-binding protein (RBP), and liver reserve of vitamin A whenever possible. Two other commonly used diagnostic tests are: functional testing for nightblindness using dark adaptation time, and pathological testing for ocular signs of conjunctival xerosis, with or without the use of Rose Bengal or lissamine green dye. Dietary method for the diagnosis of vitamin A deficiency is based on the estimation of dietary intake of vitamin A and carotenoids. In addition, there are newer methods such as isotope dilution and relative dose response (RDR) techniques which have been recently proposed for the diagnosis of vitamin A deficiency. RDR appears to be a reliable and sensitive indicator of marginal vitamin A. However, the most desirable approach to diagnosis may be one based on multiple indicators for the accurate assessment of vitamin A status in the community. The purpose of this paper is to draw attention to the problems of diagnosis, to recent advances and to our Brazilian experience in this important area of vitamin A research with significant global implications.     

D2D pervasive communication system with out-of-band control autonomous to 5G networks

Wireless Networks - D2D (device-to-device) communication is one of the developments of 5G networks (5th generation mobile networks) that reduce mobile traffic load, reduce energy consumption and...     

The Effect of Mismatches and Delay on the Quadrature Error of a Cross-Coupled Relaxation Oscillator

Cross-coupled relaxation oscillators can produce two highly accurate quadrature output signals (Verhoeven, 1992). We present a high-level model of these oscillators in terms of circuit parameters, from which we obtain explicit equations for duty-cycle, oscillation frequency, and quadrature error. They show the influence on the oscillator performance of component mismatches and other nonideal effects, such as delays. The results provide useful guidelines for the design of high performance oscillators. The theoretical results are confirmed by simulation and by measurements on a test chip.     

Physical Properties of Pecans Relating to Shelling Efficiency

Inshell pecans of 21 cultivars and numbered trial selections were evaluated for selected physical properties and for their adaptability to be efficiently shelled by existing commercial technology. Processing efficiency was based on yield of unbroken half kernels during shelling. There were highly significant differences among varieties in both selected physical properties and shelling efficiency. Correlations between shelling efficiency and physical properties were determined. Results showed that percent total kernel, inshell length/diameter ratio and shell thickness were the physical properties that appeared to have the greatest effect on shelling efficiency.