Convergence properties of the likelihood of computed dynamic models

This paper studies the econometrics of computed dynamic models. Since these models generally lack a closed-form solution, economists approximate the policy functions of the agents in the model with numerical methods. But this implies that, instead of the exact likelihood function, the researcher can evaluate only an approximated likelihood associated with the approximated policy function. What are the consequences for inference of the use of approximated likelihoods? First, we show that as the approximated policy function converges to the exact policy, the approximated likelihood also converges to the exact likelihood. Second, we prove that the approximated likelihood converges at the same rate as the approximated policy function. Third, we find that the error in the approximated likelihood gets compounded with the size of the sample. Fourth, we discuss convergence of Bayesian and classical estimates. We complete the paper with three applications to document the quantitative importance of our results.

Matrix Methods for the Dynamic Range Optimization of Continuous-TimeGm-CFilters

This paper presents a synthesis procedure for the optimization of the dynamic range of continuous-time fully differential G m - C filters. Such procedure builds up on a general extended state-space system representation which provides simple matrix algebra mechanisms to evaluate the noise and distortion performances of filters, as well as, the effect of amplitude and impedance scaling operations. Using these methods, an analytical technique for the dynamic range optimization of weakly nonlinear G m - C filters under power dissipation constraints is presented. The procedure is first explained for general filter structures and then illustrated with a simple biquadratic section

The NADPH-Dependent thioredoxin reductase C-2-Cys peroxiredoxin redox system modulates the activity of thioredoxin x in arabidopsis chloroplasts

The chloroplast redox network is composed of a complex set of thioredoxins (Trxs), reduced by ferredoxin (Fdx) via a Fdx-dependent Trx reductase (FTR), and an NADPH-dependent Trx reductase with a joint Trx domain, NTRC, which efficiently reduces 2-Cys peroxiredoxins (2-Cys Prxs). Recently, it was proposed that the redox balance of 2-Cys Prxs maintains the redox state of f-type Trxs, thus allowing the proper redox regulation of Calvin-Benson cycle enzymes such as fructose 1,6-bisphosphatase (FBPase). Here, we have addressed whether the action of 2-Cys Prxs is also exerted on Trx x. To that end, an Arabidopsis thaliana quadruple mutant, ntrc-trxx-δ "2cp, which is knocked out for NTRC and Trx x, and contains severely decreased levels of 2-Cys Prxs, was generated. In contrast to ntrc-trxx, which showed a severe growth inhibition phenotype and poor photosynthetic performance, the ntrc-trxx-δ "2cp mutant showed a significant recovery of growth rate and photosynthetic efficiency, indicating that the content of 2-Cys Prxs is critical for the performance of plants lacking both NTRC and Trx x. Light-dependent reduction of FBPase was severely impaired in mutant plants lacking NTRC or NTRC plus Trx x, despite the fact that neither NTRC nor Trx x is an effective reductant of this enzyme. However, FBPase reduction was recovered in the ntrc-trxx-δ "2cp mutant. Our results show that the redox balance of 2-Cys Prxs, which is mostly dependent on NTRC, modulates the activity of Trx x in a similar way as f-type Trxs, thus suggesting that the activity of these Trxs is highly interconnected.Ministerio de Economía y Competitividad BIO2017-85195-C2-1-

A 0.18 μm CMOS low noise, highly linear continuous-time seventh-order elliptic low-pass filter

This paper presents a fast procedure for the system-level evaluation of noise and distortion in continuous-time integrated filters. The presented approach is based on Volterra's series theory and matrix algebra manipulation. This procedure has been integrated in a constrained optimization routine to improve the dynamic range of the filter while keeping the area and power consumption at a minimum. The proposed approach is demonstrated with the design, from system- to physical-level, of a seventh-order low-pass continuous-time elliptic filter for a high-performance broadband power-line communication receiver. The filter shows a nominal cut-off frequency of fc = 34MHz, less than 1dB ripple in the pass-band, and a maximum stop-band rejection of 65dB. Additionally, the filter features 12dB programmable boost in the pass-band to counteract high frequency components attenuation. Taking into account its wideband transfer characteristic, the filter has been implemented using G m-C techniques. The basic building block of its structure, the transconductor, uses a source degeneration topology with local feedback for linearity improving and shows a worst-case intermodulation distortion of -70 dB for two tones close to the passband edge, separated by 1MHz, with 70mV of amplitude. The filter combines very low noise (peak root spectral noise density below 56nV/√Hz) and high linearity (more than 64dB of MTPR for a DMT signal of 0.5Vpp amplitude) properties. The filter has been designed in a 0.18μm CMOS technology and it is compliant with industrial operation conditions (-40 to 85°C temperature variation and ±5% power supply deviation). The filter occupies 13mm2 and exhibits a typical power consumption of 450 mW from a 1.8V voltage supply.Ministerio de Ciencia y Tecnología TIC2003-0235

System-level optimization of baseband filters for communication applications

In this paper, a design approach for the high-level synthesis of programmable continuous-time baseband filters able to achieve optimum trade-off among dynamic range, distortion behavior, mismatch tolerance and power area consumptions is presented. The proposed approach relies on building programming circuit elements as arrays of switchable unit cells and defines the synthesis as a constrained optimization problem with both continuous and discrete variables, this last representing the number of enabled cells of the arrays at each configuration. The cost function under optimization is, then, defined as a weighted combination of performance indices which are estimated from macromodels of the circuit elements. The methodology has been implemented in MATLAB™ and C++, and covers all the classical approximation techniques for filters, most common circuit topologies (namely, ladder simulation and cascaded biquad realizations) and both transconductance-C (Gm-C) and active-RC implementation approaches. The proposed synthesis strategy is illustrated with a programmable equal-ripple ladder Gm-C filter for a multi-band power-line communication modem.P.R.O.F.I.T. FIT-070000-2001-84

A 0.18μm CMOS low-noise elliptic low-pass continuous-time filter

This paper presents a seventh order low-pass continuous-time elliptic filter for use in a high-performance wireline communication receiver. As an additional attribute, the filter provides programmable boost in the pass-band to counteract high frequency components attenuation. The filter shows a nominal cutoff frequency of fc=34 MHz , less than 1dB ripple in the pass-band, and a maximum stop-band rejection of 65dB. The filter also exhibits low noise feature (peak root spectral noise density below 56nV√Hz) and high linearity (more than 64dB of MTPR for a DMT signal of 0.5Vpp amplitude). It has been designed in a 0.18μm CMOS technology and it is compliant with industrial operation conditions (-40 to 85° C temperature variation and ± 5% power supply deviation). Simulations show a typical power consumption of 450 mW @ 1.8V supply.Ministerio de Ciencia y Tecnología TIC2003-0235

Un nuevo bronce hallado en La Alcudia

Presentación del bronce de la centuriación de Ilici

Bars overlapping in tensegrity structurs belonging to the Octahedron family.

When performing the form-finding process of full-forms of tensegrity structures it is observed that beyond the double-expanded octahedron, struts overlapping occurs in space, making practicably impossible to materialize the tensegrity to employ it as a real structure. As the spatial coordinates of nodes that determine the geometry of the structure are provided as a linear combination of vectors composing a base of null space of the tensegrity force density matrix, an analytical study is carried out to check the existence of any combination of those vectors that avoids the overlapping of bars.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech