An FPGA-based emulation platform for evaluation of time-interleaved ADC calibration systems

Fil: Sanchez, Raúl M. Fundación Fulgor; Argentina.Fil: Reyes, Benjamín T. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.Fil: Pola, Ariel L. Fundación Fulgor; Argentina.Fil: Hueda, Mario R. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.This work describes a 1 Gb/s digital communication system implemented on an FPGA-based platform to investigate mixed-signal calibration techniques of time-interleaved analog-to-digital converters (TI-ADCs). Design of multi-gigabit TI-ADCs is of great interest for next generation digital communication systems such as optical coherent networks. In these applications, mismatches of the sampling time, gain, offset, and frequency response among the interleaves of a TI-ADC limit the performance of the converter unless they are compensated. Typically, long computer simulation run time is required to evaluate the performance of mixed-signal calibration algorithms. We show that the FPGA-based system described in this paper drastically reduces the emulation time by more than hundreds of magnitude orders. The proposed FPGA framework includes: (i) a diagnostic and control unit built upon an embedded processor NIOSII, (ii) DSP blocks to implement the transmitter and the receiver, and (iii) a Gaussian number generator to emulate the noise channel component. Experimental results with a 2 GS/s 6-bit CMOS TI-ADC demonstrate the excellent capability of the implemented FPGA-based emulator to evaluate the performance of a mixed-signal calibration algorithm.http://dx.doi.org/10.1109/LASCAS.2016.7451041Fil: Sanchez, Raúl M. Fundación Fulgor; Argentina.Fil: Reyes, Benjamín T. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.Fil: Pola, Ariel L. Fundación Fulgor; Argentina.Fil: Hueda, Mario R. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.Telecomunicacione

A 1.6Gb/s CMOS LVDS Transmitter with a Programmable Pre-Emphasis System

A 12 parallel low voltage differential signaling (LVDS) transmitter fabricated in 0.13 μm CMOS is presented. Each LVDS channel can operate over 1.6 Gb/s and includes a programmable pre-emphasis circuit designed to reduce the data-dependent jitter (DDJ) caused by different lengths of PCB traces. Experimental results of the fabricated LVDS confirm the correct operation of the programmable pre-equalization circuit. The power consumption and area per channel is less than 20 mW and 0.084 mm2, respectively.http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6820268Fil: Reyes, Benjamín T. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.Fil: Paulina, German. Fundación Fulgor; Argentina.Fil: Tealdi, Lucas. Fundación Fulgor; Argentina.Fil: Labat, Emanuel. Fundación Fulgor; Argentina.Fil: Sanchez, Raúl. Fundación Fulgor; Argentina.Fil: Mandolesi, Pablo S. Universidad Nacional del Sur. GISEE – LMNE; Argentina.Fil: Hueda, Mario R. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Laboratorio de Comunicaciones Digitales; Argentina.Telecomunicacione

Endoscopic decompression as management of uncomplicated sigmoid volvulus: case report and literature review

Sigmoid volvulus is a cause of intestinal obstruction explained by the twist of the sigmoid over its mesentery. The colon is at risk of ischaemia due to alterations in the irrigation due to rotation of the mesentery and risk of perforation. Surgical management is suggested in complicated cases, but endoscopic management with decompression and detorsion may be suggested in the case of uncomplicated sigmoid volvulus, with risk of recurrence. We present the case of a 49-year-old male with a diagnosis of uncomplicated sigmoid volvulus resolved by decompression with rigid proctosigmoidoscopy and medical management with remission of intestinal occlusion, without surgical intervention. A case and review of the current literature are presented

Soil and leaf mineral element contents in mediterranean vineyards: bioaccumulation and potential soil pollution

The study reported here concerns the geochemical distributions of macro- and trace elements (including potentially toxic elements, PTEs) in the vineyard soils of Alcubillas, which is one of the oldest, albeit not world-renowned, wine-growing areas in La Mancha (Central Spain). Soil and leaf samples were analyzed by X-ray fluorescence spectrometry to ascertain the levels of various elements in the soil and the plant. The potential toxicity of the elements was assessed with regard to the development of the vineyard. Despite the fact that fertilizers and pesticides are employed in the vineyards in this area, the results showed that the levels of trace elements in the soil samples did not exceed the reference values according the pedogeochemical values for the region and Spain. This finding suggests that the study area is not polluted, and therefore, there are hardly any traces of anthropogenic contamination. The Biological Absorption Coefficient (BAC) was calculated to assess the assimilation of various elements from the soil to the leaves, and differences were found in the element absorption capacity of the vines. Some elements were not taken up by Vitis vinifera despite elements like Zr and Rb being present in relatively high concentrations in the soil. The production in these soils does not represent a threat to human health or the ecosystem, because the farmers in this area are extremely careful to preserve the environment and they only farm to achieve moderate yields of grapes per hectar

A lean six sigma framework for continuous and incremental improvement in the oil and gas sector

This article aims to explore synergies between Lean Production (LP) and Six Sigma principles in order to propose a Lean Six Sigma (LSS) framework for continuous and incremental improvement in the oil and gas sector. The Three-Dimensional LSS Framework seeks to provide various combinations about the integration between LP principles, DMAIC cycle and PDCA cycle to support operations management needs. Design/methodology/approach - The research method is composed of two main steps: (i) diagnostic of current problems and proposition of a conceptual framework that qualitatively integrates synergistic aspects of LP and Six Sigma; and (ii) analysis of the application of the construct through semi-structured interviews with leaders from oil and gas companies to assess and validate the proposed framework. Findings - As a result, a conceptual framework of LSS is developed contemplating the integration of LP and Six Sigma and providing a systemic and holistic approach to problemsolving through continuous and incremental improvement in the oil and gas sector. Originality/value - This research is different from previous studies because it integrates LP principles, DMAIC and PDCA cycles into a unique framework that fulfils a specific need of oil and gas sector. It presents a customized LSS framework that guides wastes and costs reduction, while enhances quality and reduces process variability to elevate efficiency in operations management of this sector. The paper type is an original research that present new and original scientific findings.N/

Cross-sectional and longitudinal relationships between cardiorespiratory fitness and health-related quality of life in primary school children in England: the mediating role of psychological correlates of physical activity

Aims: The aims were (1) to analyse the cross-sectional and longitudinal associations between children’s cardiorespiratory fitness (CRF) and health-related quality of life (HRQoL) and (2) to examine whether these associations were mediated by physical activity self-efficacy and physical activity enjoyment. Methods: This study involved 383 children (10.0 ± 0.5 years) recruited from 20 primary schools in northwest England. Data were collected on two occasions 12 weeks apart. The number of laps completed in the 20-m Shuttle Run Test was used as the CRF indicator. HRQoL was assessed using the KIDSCREEN-10 questionnaire. Physical activity self-efficacy and enjoyment were assessed with the social-cognitive and Physical Activity Enjoyment Scale questionnaires, respectively. Linear mixed models with random intercepts (schools) assessed associations between CRF and HRQoL cross-sectionally, and longitudinally. Boot-strapped mediation procedures were performed, and indirect effects (IE) with 95% confidence intervals (CI) not including zero considered as statistically significant. Analyses were adjusted for sex, time of the year, socioeconomic status, waist-to-height ratio, maturation, and physical activity. Results: CRF was cross-sectionally associated with HRQoL (β = 0.09, 95% CI = 0.02, 0.16; p = .015). In the longitudinal analysis, CRF at baseline was associated with HRQoL at 12 weeks after additionally controlling for baseline HRQoL (β = 0.08, 95% CI = 0.002; p = .15, p = .045). Cross-sectionally, physical activity self-efficacy and enjoyment acted individually as mediators in the relationship between CRF and HRQoL (IE = 0.069, 95% CI = 0.038; p = .105 and IE = 0.045, 95% CI = 0.016; p = .080, respectively). In the longitudinal analysis, physical activity self-efficacy showed a significant mediating effect (IE = 0.025, 95% CI = 0.004; p = .054). Conclusion: Our findings highlight the influence of CRF on children’s psychological correlates of physical activity and their overall HRQoL

Constraining the Magnetic Effects on HI Rotation Curves and the Need for Dark Halos

The density profiles of dark halos are usually inferred from the rotation curves of disk galaxies based on the assumption that the gas is a good tracer of the gravitational potential of the galaxies. Some authors have suggested that magnetic pinching forces could alter significantly the rotation curves of spiral galaxies. In contrast to other studies which have concentrated in the vertical structure of the disk, here we focus on the problem of magnetic confinement in the radial direction to bound the magnetic effects on the HI rotation curves. It is shown that azimuthal magnetic fields can hardly speed up the HI disk of galaxies as a whole. In fact, based on virial constraints we show that the contribution of galactic magnetic fields to the rotation curves cannot be larger than ~10 km/s at the outermost point of HI detection, if the galaxies did not contain dark matter at all, and up to 20 km/s in the conventional dark halo scenario. The procedure to estimate the maximum effect of magnetic fields is general and applicable to any particular galaxy disk. The inclusion of the surface terms, namely the intergalactic (thermal, magnetic or ram) pressure, does not change our conclusions. Other problems related with the magnetic alternative to dark halos are highlighted. The relevance of magnetic fields in the cuspy problem of dark halos is also discussed.Comment: 12 pages, 1 figure, accepted for publication in The Astrophysical Journa

The role of disulfide bond replacements in analogues of the Tarantula toxin ProTx-II and their effects on inhibition of the voltage-gated sodium ion channel Nav1.7

Spider venom toxins, such as Protoxin-II (ProTx-II), have recently received much attention as selective Nav1.7 channel blockers, with potential to be developed as leads for the treatment of chronic nocioceptive pain. ProTx-II is a 30-amino acid peptide with three disulfide bonds that has been reported to adopt a well-defined inhibitory cystine knot (ICK) scaffold structure. Potential drawbacks with such peptides include poor pharmacodynamics and potential scrambling of the disulfide bonds in vivo. In order to address these issues, in the present study we report the solid-phase synthesis of lanthionine-bridged analogues of ProTx-II, in which one of the three disulfide bridges is replaced with a thioether linkage, and evaluate the biological properties of these analogues. We have also investigated the folding and disulfide bridging patterns arising from different methods of oxidation of the linear peptide precursor. Finally, we report the X-ray crystal structure of ProTx-II to atomic resolution; to our knowledge this is the first crystal structure of an ICK spider venom peptide not bound to a substrate